Search

Summary: Background: Augmentation mammoplasty with subpectoral prosthesis implantation is a frequent performed procedure in plastic surgery for reconstructive and aesthetic purposes. Although prosthesis implantation in a pocket under the major pectoralis muscle has been related to volumetric and functional alterations, there is not much information about the associated short- and long-term histological changes. Therefore, the aim of our study was to describe the acute and chronic histological muscle alterations associated with subpectoral prosthesis implantation. Materials and Method: We collected samples from patients with breast tissue expander (1 year after implantation) and from patients without implantation as a control group. The samples were processed for assessing their histological, histochemical and immunohistochemical properties. Results: In the control group, no relevant histological findings were identified. Additionally, in the patients with expander, we observed mild augmentation of the internalised nuclei, normal morphology, significant muscle atrophy and fibrosis, whereas in the patients with prosthesis considerable augmentation of internalised nuclei, significant muscle atrophy, fibrosis and alteration of normal muscle morphology were observed. Conclusion: Prosthesis implantation induces histological changes in the periprosthetic striated muscle. Chronic fibrosis and inflammation play key roles in this process, which should be characterised in more detail from the histological and molecular biological perspective.

Zn–Mn alloy coatings with small amounts of Mn (Zn-0.19 wt.% Mn, Zn-0.21 wt.% Mn, Zn-0.26 wt.% Mn and Zn-0.34 wt.% Mn) were formed by electrodeposition, onto pre-treated Mg substrates (Mgt) covered with a Zn film (Zn/Mgt). The chemical composition in depth profiles, morphological and structural characteristics of the Zn–Mn coatings on Zn/Mgt (labeled as Zn–Mn/(Zn/Mgt)) were analyzed using Glow Discharge Optical Emission Spectroscopy (GD-OES), Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDS), and X-ray diffraction (XRD). When the manganese content was greater than 0.19 wt.%, the results reveal the formation of two Zn–Mn phases: η-ZnMn and ζ-MnZn13; while the formation of the ζ-MnZn13 phase was favored by increasing the Mn content in the alloy. On the other hand, microhardness, wear resistance, and coefficient of friction significantly increase when coating Zn/Mgt substrate with the Zn–Mn alloy. The corrosion performance of this alloy was evaluated by potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The degradation rate in Hank's solutions of the pristine Mg substrate (0.29 mm yr−1) decreases due to the Zn–Mn coating. Furthermore, the degradation rate of Zn–Mn was further decreased from 0.051 to 0.022 mm yr−1, by varying the amount of Mn in the Zn–Mn alloy from 0.19 to 0.26 wt.% Mn, respectively. However, the rate of degradation increases up to 0.064 mm yr−1 at higher Mn content, Zn-0.34 wt.% Mn. Therefore, the microhardness, wear volume, and degradation rate of Zn–Mn/(Zn/Mg) in Hank's solution can be modulated by varying the Mn composition in the alloy.

En este trabajo se realiza la optimización de la eficiencia del sistema Inversor-Máquina de Inducción (MI) del tipo jaula de ardilla, utilizando un algoritmo basado en el Método de Punto Interior (MPI), donde las variables de entrada son el par electromagnético y la velocidad del rotor en estado estacionario, y como salidas se obtienen los valores de la eficiencia óptima y del deslizamiento. Se calcula el valor del flujo óptimo del rotor que se utiliza como referencia en el lazo de control del flujo, en el control vectorial método directo de la MI. Se obtienen resultados de simulación donde se observa el incremento de la eficiencia en estados de baja carga. Se describe la instalación experimental usada en la implementación del control vectorial con máxima eficiencia del sistema, y se muestran los resultados experimentales obtenidos. Se realiza una discusión sobre los resultados y la utilización del Método de Optimización de Punto Interior.

Abstract Background Zygomatic implants have been described as a therapeutic alternative for patients with severe maxillary atrophy in order to avoid bone augmentation procedures. Taking that into account, in these treatments, the key factor is the position of the implant, the virtual surgical planning (VSP) is widespread among most clinicians before surgery on the patient. However, there are no studies which evaluate the clinical relevance of these VSP. The aim of this study is to determine whether digital planning on zygomatic implants has any influence on the implant dimensions and position, even when performing conventional surgery afterwards. Results Fourteen zygomatic implants were placed in four patients. Pre-operative and post-operative helicoidal computed tomography were performed to each patient to allow the comparison between the digital planning and the final position of implants. Tridimensional deviation (TD), mesio-distal deviation (MDD), bucco-palatine deviation (BPD), and apico-coronal deviation (ACD) were evaluated as well as angular deviation (AD). Significative differences in apical TD were observed with a mean of 6.114 ± 4.28 mm (p < 0.05). Regarding implant position, only implants placed in the area of the first right molar reported significant differences (p < 0.05) for ACD. Also, implant length larger than 45 mm showed BPD significative differences (p < 0.05). Conclusions Zygomatic implant surgery is a complex surgical procedure, and although VSP is a useful tool which helps the clinician determine the number and the length of zygomatic implants as well as its proper position, surgical experience is still mandatory.

Abstract The main aim of this study was to generate an adequate sub-phenotypic clustering model of class III skeletal malocclusion in an adult population of southern European origin. The study design was conducted in two phases, a preliminary cross-sectional study and a subsequent discriminatory evaluation by main component and cluster analysis to identify differentiated skeletal sub-groups with differentiated phenotypic characteristics. Radiometric data from 699 adult patients of southern European origin were analyzed in 212 selected subjects affected by class III skeletal malocclusion. The varimax rotation was used with Kaiser normalization, to prevent variables with more explanatory capacity from affecting the rotation. A total of 21,624 radiographic measurements were obtained as part of the cluster model generation, using a total set of 55 skeletal variables for the subsequent analysis of the major component and cluster analyses. Ten main axes were generated representing 92.7% of the total variation. Three main components represented 58.5%, with particular sagittal and vertical variables acting as major descriptors. Post hoc phenotypic clustering retrieved six clusters: C1:9.9%, C2:18.9%, C3:33%, C4:3.77%, C5:16%, and C6:16%. In conclusion, phenotypic variation was found in the southern European skeletal class III population, demonstrating the existence of phenotypic variations between identified clusters in different ethnic groups.

Abstract This investigation demonstrates the feasibility to fabricate high quality ceramic-carbonate membranes based on mixed-conducting ceramics. Specifically, it is reported the simultaneous CO2/O2 permeation and stability properties of membranes constituted by a combination of ceramic and carbonate phases, wherein the microstructure of the ceramic part is composed, in turn, of a mixture of fluorite and perovskite phases. These ceramics showed ionic and electronic conduction, and at the operation temperature, the carbonate phase of the membranes is in liquid state, which allows the transport of $$\rm{CO}_3^{2-}$$ C O 3 2 − and O2− species via different mechanisms. To fabricate the membranes, the ceramic powders were uniaxially pressed in a disk shape. Then, an incipient sintering treatment was carried out in such a way that a highly porous ceramic was obtained. Afterwards, the piece is densified by the infiltration of molten carbonate. Characterization of the membranes was accomplished by SEM, XRD, and gas permeation techniques among others. Thermal and chemical stability under an atmosphere rich in CO2 was evaluated. CO2/O2 permeation and long-term stability measurements were conducted between 850 and 940 °C. The best permeation-separation performance of membranes of about 1 mm thickness, showed a maximum permeance flux of about 4.46×10−7 mol·m−2·s−2·Pa−1 for CO2 and 2.18×10−7 mol·m−2·s−1·Pa−1 for O2 at 940 °C. Membranes exhibited separation factor values of 150–991 and 49–511 for CO2/N2 and O2/N2 respectively in the studied temperature range. Despite long-term stability test showed certain microstructural changes in the membranes, no significant detriment on the permeation properties was observed along 100 h of continuous operation.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents in some cases with hemostatic and thrombotic complications. Pheochromocytomas are unusual, though potentially lethal tumors. Herein we describe the first case of hemorrhage in a pheochromocytoma related to SARS-CoV-2 infection. A 62-year-old man consulted for syncope, fever, and palpitations. He was diagnosed with SARS-CoV-2 pneumonia and presented with a hemorrhage in a previously unknown adrenal mass, which resulted in a catecholaminergic crisis. Medical treatment and surgery were required for symptom control and stabilization. We hereby alert clinicians to watch for additional/unreported clinical manifestations in COVID-19 infection.

Resumen: En este trabajo se presenta el diseño e implementación de tres controladores: control proporcional-integral, control proporcional-integral más controlador resonante y una nueva propuesta de control configurada con un control proporcional-integral + controlador proporcional más controlador resonante. El diseño de estos controladores está orientado a la operación de inversores en modo isla dentro del contexto de las microrredes, su rendimiento ha sido validado por medio de resultados de simulaciones y por medio de pruebas experimentales. Particularmente, la configuración de control propuesta presenta como ventaja respecto a los otros dos controladores, el evitar fenómenos de saturación que se presentan en los sistemas, los cuales ocurren cuando se presentan señales de control de gran amplitud. Además de mejorar el rechazo de perturbaciones que se presentan, cuando el inversor alimenta cargas lineales y no lineales. Es decir, con la combinación de ambos controladores, se consigue una solución adecuada para reducir la distorsión armónica total en la tensión de salida de un inversor monofásico, cuando se alimentan cargas en forma aislada o bien con el inversor desconectado de la red. Palabras clave: Controlador PI-P, controlador resonante, inversor monofásico, microrred, modo isla

The Wx gene, which encodes waxy proteins, is the sole gene responsible for amylose synthesis in the wheat seed endosperm. In this study, we characterized, at the molecular level, several Wx alleles in durum wheat (Triticum turgidum L. ssp. durum Desf.) that had previously been catalogued at the protein level. Our data show a misclassification of the alleles in both Wx genes: Wx-A1 alleles from Blanqueta (Wx-A1a) and Astrodur (Wx-A1b) have been reclassified as Wx-A1a and Wx-A1h, respectively. A sequence comparison of the Wx-B1e allele shows that there were up to five different alleles under this denomination, which confirms that the protein analysis by SDS-PAGE separation needs to be combined with the PCR amplification-sequencing analysis in order to obtain a correct classification of the alleles, which will facilitate their use in wheat quality improvement.

The paper deals with the observer design problem for a flux in permanent magnet synchronous motors. It is assumed that some electrical parameters such as resistance and inductance are known numbers. But the flux, the angle and the speed of the rotor are unmeasurable. The new robust approach to design an adaptive flux observer is proposed that guarantees globally boundedness of all signals and, moreover, exponential convergence to zero of observer error between the true flux value and an estimate obtained from the adaptive observer. The problem of an adaptive flux observer design has been solved with using the trigonometrical properties and linear filtering which ensures cancellation of unknown terms arisen after mathematical calculations. The key idea is the new parameterization of the dynamical model containing unknown parameters and depending on measurable current and voltage in the motor. By applying the Pythagorean trigonometric identity the linear equation has found that does not contain any functions depending on angle or angular velocity of the rotor. Using dynamical first-order filters the standard regression model is obtained that consists of unknown constant parameters and measurable functions of time. Then the gradient-like estimator is designed to reconstruct unknown parameters, and it guarantees boundedness of all signals in the system. The proposition is proved that if the regressor satisfies the persistent excitation condition, meaning the “frequency-rich” signal, then all errors in observer exponentially converges to zero. It is shown that observer error for the flux explicitly depends on estimator errors. Exponential convergence of parameter estimation errors to zero yields exponential convergence of the flux observer error to zero. The numerical example is considered.

Abstract. A problem of output robust control for a system with power nonlinearity is considered. The considered problem can be rewritten as a stabilization problem for a system with polynomial nonlinearity by introducing the error term. The problem of temperature regulation is considered as application; the rapid thermal processes in vapor deposition processing are studied. Modern industrial equipment uses complex sensors and control systems; these devices are not available for laboratory setups. The limited amount of available sensors and other technical restrictions for laboratory setups make it an actual problem to design simple low-order output control laws. The problem is solved by the consecutive compensator approach. The paper deals with a new type of restriction which is a combination of linear and power restrictions. It is shown that the polynomial nonlinearity satisfies this restriction. Asymptotical stability of the closed-loop system is proved by the Lyapunov functions approach for the considered nonlinear function; this contribution extends previously known results. Numerical simulation of the vapor deposition processing illustrates that the proposed approach results in zero-mean tracking error with standard deviation less than 1K.

Background. Introduction of the common carp, Cyprinus carpio Linnaeus, 1758, may cause a cascade of alterations in trophic webs, among other negative effects, indirectly due to its feeding behaviour. A simplified model site, covenient for studying such interrelations is Lago de Pátzcuaro, México, a shallow lake where carp was first introduced in 1974. The aim of our study was to characterize diet composition, diet breadth and trophic position of C. carpio and local fish fauna, and to assess diet overlap between fish fauna from sites with different habitat characteristics during the wet and the dry seasons. Materials and methods. We assessed the diet of C. carpio and local fish fauna in six sites during the wet and the dry seasons. Stomach content analysis was carried out separately for each length class. The importance of each item was estimated by the index of relative importance (IRI) and the omnivory index was used to assess the feeding behaviour. The trophic guild and trophic position were determined using the TrophLab software and stable isotope analysis. Diet breadth was calculated by Levin’s Index and diet overlap by the Horn’s Index. Fish dorsal muscle and water hyacinth tissues were obtained from nitrogen isotope signature analysis. Results. We found that C. carpio is an omnivorous fish that feeds in shallow areas with water hyacinth cover and rooted macrophytes, consuming mainly detritus and plant debris (>60%). However, δ 15N values indicate that C. carpio is also a secondary consumer because it also ingests invertebrates associated with plant debris. The carp diet overlaps with native blackfin, Goodea atripinnis Jordan, 1880, at most sites. Small carp (

Graphite-coated iron nanoparticles were prepared from magnetite nanoparticles by chemical vapour deposition (CVD) under methane and hydrogen atmosphere. After being purified from carbon excess, graphite-coated iron nanoparticles were tested for morphological and magnetic properties. It was found that, during the thermal process, magnetite nanoparticles 6 nm in size coalesce and transform into graphite-coated iron 200 nm in size, as revealed by scanning electron microscopy (SEM). Raman characterization assessed that high-quality graphite coats the iron core. Magnetic measurements revealed the phase change (magnetite to iron) as an increase in the saturation magnetization from 50 to 165 emu/g after the CVD process.

En este trabajo, se describe el fenómeno de la degradación por corrosión electroquímica de los metales, sus efectos y costos, así como algunas de las técnicas empleadas para minimizar su impacto. Se hace énfasis en la descripción y mecanismo de acción de los inhibidores de corrosión y, con base en lo anterior, se plantea que el uso de estas substancias puede constituir un enfoque efectivo y relativamente barato para controlar la corrosión de algunos metales. En la última parte del artículo, se discuten brevemente algunas de las técnicas comúnmente empleadas para evaluar la actuación de los inhibidores de corrosión y algunos criterios generales para hacer una selección apropiada de los mismos.

Resumen: El bullying ha sido identificado como uno de los principales problemas que afecta a la calidad de las relaciones interpersonales que establecen los escolares. Las aportaciones científicas sobre este fenómeno se centran de forma destacada en el estudio de los factores de riesgo asociados a rasgos de la personalidad y a variables de contexto entre los iguale, principalmente en la etapa de secundaria. Sin embargo, poco se sabe de la influencia explicativa en el bullying de cada uno de estos grandes bloques. El trabajo que aquí se presenta pretende conocer si junto con ciertas variables de personalidad (sexo, edad y autoestima) existen variables del contexto escolar (ajuste normativo, indisciplina y disruptividad, ajuste entre iguales), que puedan estar explicando la implicación en bullying ya sea como agresor, víctima o agresor victimizado. El “Cuestionario para la Investigación de la Violencia Escolar en Andalucía: CIVEA” fue administrado a 1278 escolares españoles (47.7% chicas), de la región sur- Andalucía, de Educación Primaria en edades comprendidas entre los 10 a 14 años (M = 11.11; DT=0.754). Los análisis de regresión logística multinomial señalan que las variables de contexto entre iguales son las más influyentes en el bullying, concretamente el ajuste social con los iguales, la disciplina e indisciplina escolar y la autoestima positiva y negativa se destacan en casi todos los roles de implicación. Se discuten los resultados en base a las aportaciones científicas que explican la influencia de la autoestima y, principalmente de la indisciplina y disruptividad y del ajuste social, cuya mejora dentro de los centros escolares puede ser un factor de prevención.