[Bibliometric study and analysis of citation networks of visual screening in primary care]. / Estudio bibliométrico y análisis de redes de citación de los screening visuales en atención primaria.

AIM: Screenings make it possible to detect anomalies that can be treated and identify patients who require referral to a specialist. The objective is to identify the different areas of research and determine the most cited publications on screening in primary care. METHODS: An analysis of publications and visualization of citation networks has been carried out using the Citation Network Explorer software. The bibliographic search was carried out with the Web of Science (WOS) database using the search term: "screening AND (vision OR eye OR ocular OR visual)". RESULTS: We analyzed 16707 publications in all fields, 23919 citation networks have been found. The number of publications has increased, with 2021 being the year with the highest number. The majority are scientific articles and the predominant language is English. The most cited article is a global meta-analysis on the prevalence of glaucoma, showing the importance of screening for its early detection since it is essential to avoid blindness. Using the clustering function we found 8 groups with a significant number of publications where we have bibliography on certain eye diseases: glaucoma, diabetic retinopathy, pediatric amblyopia, keratoconus and dry eye. CONCLUSIONS: The main areas of study in relation to screening are the detection of diseases such as glaucoma, retinopathy of prematurity, keratoconus and dry eye. As well as the detection through visual analysis of childhood amblyopia and vision loss in elderly patients. It also gives importance to performing ocular motility tests in problems of acquired brain damage.

Comparison of different cryoprotectants for freezing donkey (Equus asinus) semen.

The aim of this study was to evaluate two cryoprotectants, dimethylformamide (DMF) and methylformamide (MF) in two concentrations (5 and 7 %) in vitro in donkey semen using a rapid freezing technique and the effect on pregnancy rates in mares. Twenty-four ejaculates from 8 jacks (n = 8; r = 3) were divided into 4 extenders: BotuSemen Gold with 5 % or 7 % MF and 5 % or 7 % DMF, all containing 11 % lactose, 20 % egg-yolk and 0.5 % Equex. Post-thaw evaluations included: sperm motility, membrane function and acrosome status. A linear mixed effect model was used to test the effect of different freezing media on semen parameters. No differences were observed between the 4 freezing media used, for any of the seminal parameters (P > 0.05). However, samples with 5 % DMF showed the highest percentages of sperm with acrosomes and functional membranes (DMF: 5 %: 53.67 ± 22.01; 7 %: 33.92 ± 23.4; MF: 5 %: 44.5 ± 20.46; 7 %: 38.75 ± 27.4) (Data: mean ± SD; P > 0.05). Hence, thirty mares were inseminated: 15 with 5 % DMF and 15 with 7 % DMF. The pregnancy rate was 46 % (7/15) and 0 % (0/15) using the extender with 5 % or 7 % DMF, respectively (P = 0.003). To conclude, the use of 5 % or 7 % of MF or DMF did not affect the in vitro parameters. Despite the lack of differences in vitro with the two DMF concentrations, in vivo results only showed pregnancies when using 5 % DMF. Thus, the results of this study demonstrate the importance of accompanying in vitro semen evaluations with studies that evaluate post-insemination pregnancy rates.

Prader-Willi syndrome in a large sample from Spain: general features, obesity and regular use of psychotropic medication.

BACKGROUND: Prader-Willi syndrome (PWS), a genetically determined disorder, the most frequent cause of early onset obesity, is associated with physical and cognitive dysfunctions and behavioural disturbances; these disturbances are frequently treated with psychotropic medication. The aim of this cross-sectional study was to describe the characteristics of the first large national sample of persons with PWS in Spain and analyse the relationships of those characteristics with key demographic and clinical factors, particularly with obesity and the regular use of psychotropic medication. METHODS: Participants were recruited among all members of the Spanish Prader-Willi Association who agreed to take part in the study and fulfilled its inclusion criteria. Family and patient demographic features, family size and birth order, intelligence quotient (IQ), anthropometric measures, lifestyle habits, behavioural disturbances (with the Aberrant Behavior Checklist) and clinical data, as well as use of psychotropic drugs and their side effects (with the UKU scale), were collected in genetically confirmed cases of PWS. Bivariate and logistic regression analyses were used for determining the associations of demographic and clinical factors with both obesity and the regular use of psychotropic medication. RESULTS: The cohort included 177 participants (aged 6-48 years), that is, 90 (50.8%) males and 87 (49.2%) females. Behavioural disturbances were present in a range of 75% to 93% of participants; psychotropic medication was prescribed to 81 (45.8%) of them. Number of siblings showed a direct correlation with IQ, especially among males, and inappropriate speech was more intense in only-child females. Obesity was, in parallel, strongly associated with ascending age and with not being currently under growth hormone (GH) treatment. Participants taking any psychotropic medication were characterised by more frequent age ≥30 years, high level of hyperactivity and a psychiatric diagnosis. CONCLUSIONS: Characterisation of persons with PWS in Spain confirms their physical and behavioural phenotype and supports the long-term application of GH therapy and the rational use of psychotropic medication.

Pregnancy and birth rate outcomes in alpacas (Vicugna pacos) inseminated with frozen semen using two commercial extenders.

The aim of this study was to evaluate alpaca pregnancy outcomes and birth rates of females inseminated with frozen semen using two commercial extenders. A total of 18 ejaculates from 8 adult alpaca males were obtained with artificial vagina, and macroscopic and microscopic semen characteristics were assessed. Afterwards, samples were divided into two aliquots, diluted with Biladyl® B or AndroMed®, and cooled for 2 h at 5°C. At that moment, sperm motility was evaluated, and samples were frozen through a gradual descent of temperature using a liquid nitrogen tank. To analyse frozen sperm quality, samples were thawed at 38°C for 30 s. Even though a significant decrease in sperm motility and viability was detected when thawed (p < .05), no superiority was found between the two commercial extenders (Biladyl® B vs. AndroMed®). A total of 36 alpaca females were artificially inseminated (AI) between 30 and 34 h post-injection of a GnRH analogue, administered when a growing dominant follicle was detected through transrectal palpation and ultrasonography. Obtained pregnancy rates were similar between Biladyl® B (33.3%, 6/18) and AndroMed® (22.2%, 4/18). No significant differences were detected in birth rates between the two tested extenders, obtaining 4 and 3 births for Biladyl® and AndroMed®, respectively. In conclusion, alpaca pregnancies and alive offspring can be obtained through AI with frozen semen at similar efficiency rates using commercial diluents, Biladyl® B or AndroMed®.

Biophysical effects of a natural peloid on normal skin.

A protocol study was designed to examine cutaneous behavior after continuous application of a peloid in the dry mineral residue of Lanjarón-Capuchina natural mineral water. This study aims to analyze the biomechanical behavior of normal skin using various non-invasive bioengineering techniques after the application of this peloid. We determine the effects of its application for 3 months on 38 healthy volunteers (41.4 ± 5.9 years, range 32-58) without a previous history of skin diseases by courtmetry, sebumetry, pH-metry, reviscometry, and tewametry. It was shown that the production of cutaneous sebum is significantly reduced by 6%, trans epidermal skin loss (TEWL) by 21%, skin fatigue by 30%, elasticity increased by 19%, firmness by 5%, and a skin redensification by 6% was obtained under these experimental conditions. Disparate and non-significant results were obtained concerning pH and viscoelasticity. Continuous skin care with the Lanjarón-Capuchina natural peloid modifies skin behavior, normalizing sebaceous secretion, favoring the biomechanical properties of the skin and the skin barrier function without modifying skin homeostasis.

The importance of cell uptake in photothermal treatments mediated by biomimetic magnetic nanoparticles.

Biomimetic magnetic nanoparticles (BMNPs) mediated by MamC have proven to be photothermal agents able to allow an optimized cytotoxicity against tumoral cells when used simultaneously as drug nanotransporters and as hyperthermia agents. However, it remains unclear whether BMNPs need to be internalized by the cells and/or if there is a threshold for internal Fe concentration for the photothermal therapy to be effective. In this study, three different situations for photothermal treatments have been simulated to disentangle the effect of BMNPs cell uptake on cell viability after photothermal treatments. Human hepatoblastoma (HepG2) cell line was treated with suspensions of BMNPs, and protocols were developed to have only intracellular BMNPs, only extracellular BMNPs or both, followed by photothermal exposure of the treated cell cultures. Our data demonstrate that: (1) Although the heating efficiency of the photothermal agent is not altered by its location (intra/extracellular), the intracellular location of BMNPs is crucial to ensure the cytotoxic effect of photothermal treatments, especially at low Fe concentration. In fact, the concentration of BMNPs needed to reach the same cytotoxic effect following upon laser irradiation of 0.2 W/cm2 is three times larger if BMNPs are located extracellularly compared to that needed if BMNPs are located intracellularly; (2) For a given location of the BMNPs, cell death increases with BMNPs (or Fe) concentration. When BMNPs are located intracellularly, there is a threshold for Fe concentration (∼ 0.5 mM at laser power intensities of 0.1 W/cm2) needed to affect cell viability following upon cell exposure to photothermia. (3) Bulk temperature rise is not the only factor accounting for cell death. Actually, temperature increases inside the cells cause more damage to cell structures and trigger cell death more efficiently than an increase in the temperature outside the cell.

Haematology and biochemistry in healthy llamas at sea level.

In the last years, there has been an increasing interest in llamas, not only as part of a productive system, but mostly as companion animals. Most reports regarding clinical biochemistry and haematology include few llamas and details about their health status are not available. The present study aims to provide haematological and biochemical parameters for llamas of known health status. Twenty-three non-pregnant females and seven males that live in Buenos Aires, Argentina (34°36'S, 58°22'W, at sea level) were studied. Llamas were clinically healthy, in good nutritional status. Animals were kept at grass and were fed hay bale or pellets and water ad libitum. Blood samples were collected by jugular venipuncture in spring. Packed cell volume, leucocyte count, differential white cell count, platelets count, urea, creatinine, total proteins, albumin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, glucose, calcium and phosphate were assessed. No significant differences were observed between males and females, except for platelet count and calcium, which was greater in males (P˂0.01). Values obtained for the different parameters were similar to those previously reported, except for monocytes, alkaline phosphatase, glucose and calcium, that were lower and lymphocytes and platelets count, that were higher in this study. In conclusion, different ambient and methodological conditions might affect some parameters. The parameters hereby presented are representative of llama's population living at sea level in South America.

Soliton approximation in continuum models of leader-follower behavior.

Complex biological processes involve collective behavior of entities (bacteria, cells, animals) over many length and time scales and can be described by discrete models that track individuals or by continuum models involving densities and fields. We consider hybrid stochastic agent-based models of branching morphogenesis and angiogenesis (new blood vessel creation from preexisting vasculature), which treat cells as individuals that are guided by underlying continuous chemical and/or mechanical fields. In these descriptions, leader (tip) cells emerge from existing branches and follower (stalk) cells build the new sprout in their wake. Vessel branching and fusion (anastomosis) occur as a result of tip and stalk cell dynamics. Coarse graining these hybrid models in appropriate limits produces continuum partial differential equations (PDEs) for endothelial cell densities that are more analytically tractable. While these models differ in nonlinearity, they produce similar equations at leading order when chemotaxis is dominant. We analyze this leading order system in a simple quasi-one-dimensional geometry and show that the numerical solution of the leading order PDE is well described by a soliton wave that evolves from vessel to source. This wave is an attractor for intermediate times until it arrives at the hypoxic region releasing the growth factor. The mathematical techniques used here thus identify common features of discrete and continuum approaches and provide insight into general biological mechanisms governing their collective dynamics.

Risk of severe COVID in solid organ transplant recipient.

Despite the fact that COVID is today not a life-threat for the general population, recipients of solid organ transplantation should be viewed as a high risk group for severe COVID. Repetitive doses of SARS-CoV-2 vaccine still fail to protect SOT recipients from infection, disease or even death caused by COVID. A more frequent need for medical care may initially place these patients at greater chances of SARS-CoV-2 infection. Immunosuppression after engrafting and underlying medical conditions that led to the practice of SOT contribute to more risk of severe infection. Immunosuppression also blunts the intensity of humoral and cellular responses after vaccination, even when several booster doses have been administered. Still, vaccination is the best strategy to prevent a fatal outcome in case of SARS-CoV-2 infection, with a particular reduction in mortality. SOT recipients should be considered a high-risk population that need yearly SARS-CoV-2 vaccination.

La habilidad lingüística en el primer ciclo de Educación Primaria en alumnado nacido prematuro extremo / Linguistic ability in the first cycle of Education Primary of students born prematurely extreme

La prematuridad tiene una alta tasa de incidencia en los países desarrollados, representando el 75% de la mortalidad perinatal. Aunque los avances prenatales y perinatales de las últimas décadas han permitido reducir su prevalencia, en consecuencia, se ha hecho evidente la presencia de morbilidades y comorbilidades en el desarrollo de estos infantes.El propósito de esta investigación, de carácter prospectivo y longitudinal, es analizar los componentes del lenguaje (morfología, sintaxis, semántica y pragmática) de 29 menores, nacidos prematuros extremos, en el Hospital Universitario La Paz de Madrid y que actualmente están en edad escolar obligatoria, para identificar la presencia de posibles dificultades en el lenguaje. Todos los participantes estaban matriculados en Educación Primaria y los componentes del lenguaje se evaluaron a través de la batería BLOC-Screening.Los resultados evidencian que existen comorbilidades en el componente morfológico en los siguientes elementos: formas irregulares de pasado, formas irregulares de futuro, reflexivos…; en el componente semántico (locativos, cuantificadores, modificadores de tiempo y sucesión…) y en sintaxis (voz pasiva, oraciones comparativas, oraciones subordinadas de causa y condición, y en las temporales [después/antes]…), obteniéndose mejores resultados en el componente pragmático, excepto en aquellas acciones que requieren expresar demandas y solicitar información específica.Por tanto, el perfil obtenido en lenguaje de los prematuros extremos sugiere la necesidad de intervención logopédica y conlleva la necesidad de hacer propuestas de intervención didáctica en la escuela que mejoren sus habilidades lingüísticas desde un enfoque comunicativo.(AU)

Prematurity has a high incidence rate in developed countries, accounting for 75% of perinatal mortality. Although pre- and perinatal advances in recent decades have reduced its prevalence, consequently, the presence of morbidities and comorbidities in the development of these infants has become evident.The purpose of this prospective and longitudinal research is to analyze the language components (morphology, syntax, semantics and pragmatics) of 29 minors, born extremely premature, at the Hospital Universitario La Paz in Madrid and who are currently of compulsory school age, in order to identify the presence of possible language difficulties. All the participants were enrolled in Primary Education and the language components were assessed using the BLOC-Screening battery.The results show that there are comorbidities in the morphological component in the following elements: irregular forms of the past, irregular forms of the future, reflexive…; in the semantic component (locatives, quantifiers, modifiers of time and succession…) and in syntax (passive voice, comparative clauses, subordinate clauses of cause and condition, and in the temporal ones [after/before]…), obtaining better results in the pragmatic component, except in those actions that require expressing demands and requesting specific information.Therefore, the profile obtained in the language of extremely premature infants suggests the need for speech therapy intervention and entails the need to make proposals for educational intervention at school that improve their language skills from a communicative approach.(AU)

Estudio sobre la prevalencia de expresión del pd-l1 en las Células Neoplásicas en nuestros pacientes sometidos a EBUS-TBNA / Study on the prevalence of pd-l1 expression in neoplastic cells in our patients undergoing EBUS-TBNA

El Cáncer de pulmón es la primera causa mundial de muertepor Cáncer. La inmunoterapia con anticuerpos monoclonales antiPD-L1 ha supuesto un avance en su tratamiento. En nuestro estudiose ha revisado la prevalencia de este receptor en las muestrasobtenidas mediante aspiración con aguja transbronquial guiada porecobroncoscopia (EBUS-TBNA). (AU)

Lung cancer is the world's leading cause of death from cancer.Immunotherapy with anti-PD-L1 monoclonal antibodies hasrepresented an advance in its treatment. In our study, we reviewedthe prevalence of this receptor in samples obtained by ultrasoundguided transbronchial needle aspiration (EBUS-TBNA). (AU)

Hallazgo casual al regresar de un viaje / Chance find when returning from a trip

Se trata de un varón de 34 años que tras regresar de un viaje transatlántico consulta por dolor pleurítico derecho, malestar general, sudoración y tos productiva. Presenta alteraciones radiológicas compatibles con tromboembolismo pulmonar (TEP) bilateral, patrón micronodular y adenopatías mediastínicas que podrían estar en relación con algún proceso infeccioso-inflamatorio por el que inicia estudio. Tras aplicar una amplia estrategia diagnóstica y excluir otras enfermedades, el resultado es compatible con TEP bilateral coincidente con sarcoidosis pulmonar estadio II. El paciente evoluciona posteriormente de forma favorable con tratamiento corticoideo. (AU)

This is a 34-year-old man who, after returning from a transatlantic trip, consulted for right pleuritic pain, general malaise, sweating, and a productive cough. He presented radiological alterations compatible with bilateral pulmonary thromboembolism (PTE), a micronodular pattern and mediastinal lymphadenopathies that could be related to some infectious-inflammatory process for which he began the study. After applying a broad diagnostic strategy and excluding other diseases, the result is compatible with bilateral PET coinciding with stage II pulmonary sarcoidosis. The patient subsequently evolves favorably with corticosteroid treatment. (AU)

Mechanistic interrogation of mutation-independent disease modulators of RDEB identifies the small leucine-rich proteoglycan PRELP as a TGF-ß antagonist and inhibitor of fibrosis.

Recessive dystrophic epidermolysis bullosa (RDEB) is a genetic extracellular matrix disease caused by deficiency in type VII collagen (Col VII). The disease manifests with devastating mucocutaneous fragility leading to progressive fibrosis and metastatic squamous cell carcinomas. Although Col VII abundance is considered the main predictor of symptom course, previous studies have revealed the existence of mutation-independent mechanisms that control disease progression. Here, to investigate and validate new molecular modifiers of wound healing and fibrosis in a natural human setting, and toward development of disease-modulating treatment of RDEB, we performed gene expression profiling of primary fibroblast from RDEB siblings with marked phenotypic variations, despite having equal COL7A1 genotype. Gene enrichment analysis suggested that severe RDEB was associated with enhanced response to TGF-ß stimulus, oxidoreductase activity, and cell contraction. Consistently, we found an increased response to TGF-ß, higher levels of basal and induced reactive oxygen species (ROS), and greater contractile ability in collagen lattices in RDEB fibroblasts (RDEBFs) from donors with severe RDEB vs mild RDEB. Treatment with antioxidants allowed a reduction of the pro-fibrotic and contractile phenotype. Importantly, our analyses revealed higher expression and deposition in skin of the relatively uncharacterized small leucine-rich extracellular proteoglycan PRELP/prolargin associated with milder RDEB manifestations. Mechanistic investigations showed that PRELP effectively attenuated fibroblasts' response to TGF-ß1 stimulus and cell contractile capacity. Moreover, PRELP overexpression in RDEBFs enhanced RDEB keratinocyte attachment to fibroblast-derived extracellular matrix in the absence of Col VII. Our results highlight the clinical relevance of pro-oxidant status and hyper-responsiveness to TGF-ß in RDEB severity and progression. Of note, our study also reveals PRELP as a novel and natural TGF-ß antagonist with a likely dermo-epidermal pro-adhesive capacity.

Seudotumor inflamatorio y tumor miofibroblástico inflamatorio. Criterios diagnósticos y diferencias pronósticas / Inflammatory pseudotumor and myofibroblastic inflammatory tumor. Diagnostic criteria and prognostic differences

Introducción El seudotumor inflamatorio (PTI) y el tumor miofibroblástico inflamatorio (TMI) son 2 entidades muy poco frecuentes que se incluían antiguamente en la misma categoría; sin embargo, en la actualidad se consideran 2 enfermedades diferentes debido al origen neoplásico del TMI. Nuestro objetivo es compartir nuestra experiencia en el manejo de estos 2 tipos de lesiones que debemos tener en cuenta en el diagnóstico diferencial de masas o nódulos pulmonares. Métodos Fueron estudiados retrospectivamente 13 pacientes con diagnóstico anatomopatológico de PTI o TMI, intervenidos entre los años 2008 y 2019. Registramos la información pre y postoperatoria de cada uno, así como el análisis de supervivencia. Resultados De los 13 pacientes, 8 eran varones y 5 mujeres. La media de edad de presentación fue de 53,5 años. En 6 pacientes se practicó una segmentectomía atípica, en 6 fue necesario realizar una lobectomía y en un caso una neumonectomía. En todos los casos se consiguió una resección completa. El diagnóstico fue posible gracias a la histología, técnicas de inmunohistoquímica (IHQ) y de hibridación fluorescente in situ (FISH) determinando la expresión de IgG4 y el reordenamiento de ALK, respectivamente. Tras una mediana de seguimiento de 49 meses no se observaron datos de recidiva locorregional ni a distancia en los pacientes estudiados. Conclusión El PTI y el TMI son tumores poco frecuentes con muy buen pronóstico. El diagnóstico de ambas entidades se basa principalmente en técnicas anatomopatológicas específicas. La cirugía tiene, en la mayor parte de las ocasiones, un papel tanto diagnóstico como terapéutico (AU)

Introduction Inflammatory pseudotumor (IPT) and inflammatory myofibroblastic tumor (IMT) are two very rare entities that were formerly included in the same category; however, today they are considered two different diseases due to the neoplastic origin of the IMT. Our objective is to share our experience in the management of these two types of tumors that we must take into account in the differential diagnosis of pulmonary masses or nodules. Methods Thirteen patients with a pathological diagnosis of IPT and IMT who underwent surgery between 2008 and 2019 were retrospectively studied. We recorded the pre and postoperative information of each one, as well as the survival analysis. Results Of the 13 patients, 8 were men and 5 women. The mean age of presentation was 53,5 years. An atypical segmentectomy was performed in 6 patients; a lobectomy was necessary in 6 and a pneumonectomy in 1 case. In all cases a complete resection was achieved. Diagnosis was possible thanks to histology, immunohistochemical (IHQ) and fluorescent in situ hybridization (FISH) techniques determining the expression of IgG4 and the rearrangement of ALK, respectively. After a median follow up of 49 months, we didńt find any loco-regional or distant recurrence in the patients studied. Conclusion IPT and IMT are rare tumors with a very good prognostic. The diagnosis of both entities is based mainly on specific anatomopathological techniques. Surgery has, in most cases, both a diagnostic and therapeutic role (AU)

Myopia progression and axial elongation in Spanish children: Efficacy of atropine 0.01% eye-drops.

PURPOSE: To assess myopia progression in Spanish children and whether treatment with low-dose atropine eye drops delays myopia progression and axial elongation. METHODS: 339 eyes of 339 Caucasian patients with myopia, aged 5 to 11 years, were examined. Participants were randomized to a treatment arm, receiving one atropine (0.01%) eye drop/day for two, and an untreated control arm. At the baseline and 2-year follow-up visits, we recorded: spherical equivalent (SE), axial length (AL), mean keratometry (Mean-K) and anterior chamber depth (ACD). We also examined the rate of children with higher myopia progression (change in SE >1 D/2 years) and identified risk factors for progression. RESULTS: In 339 eyes of the 339 children (age=7.61; SD 1.70; range 5-11 years), the mean baseline SE was-2.15 (SD 0.62) D, and AL was 24.24 (SD 0.79) mm. After 2 years, higher increases occurred in all variables except ACD in the untreated group vs. the atropine group, respectively: SE (-0.51 (SD 0.39) D vs. -0.76 (SD 0.37) D, P<0.001), AL (0.20 (SD 0.20) mm vs. 0.37 (SD 0.27) mm, P<0.001) and Mean-K (0.01 (0.28) D vs. 0.09 (0.32) D, P=0.018). Myopia progression was reduced by 32% in the treatment group. There were more progressors >1D/2y in the control group: 62/168 (36.9%) vs. 35/171 (20.5%) (P<0.001). Atropine was identified as a protective factor against myopia progression (B=1.12; 95% CI= 0.98-1.27; P=<0.001). CONCLUSION: Spanish children showed a low rate of myopia progression. Atropine 0.01% showed a significant effect in slowing the progression of both refractive error and axial elongation.

Infection and infectivity: Utility of rapid antigen tests for the diagnosis of COVID-19.

Detection of SARS-CoV-2 proteins is commercially available in the form of lateral-flow rapid antigen test for the point-of-care diagnosis of COVID-19. This platform has been validated for symptomatic and asymptomatic individuals, for diagnosis or screening, and as part of single or sequential diagnostic strategies. Although in general less sensitive than amplification techniques, antigen tests may be particularly valid during the first days of symptoms and to detect individuals with greater viral load, thereby with enhanced chances of viral transmission. The simplicity of antigen tests make them very suitable to discard infection in settings with low pretest probability, and to detect infection in case of higher chances of having COVID-19.

Approach to COVID-19 pandemic management in Madrid. Chronic of a year.

After more than a year of pandemic, the international medical community has changed the perception of fear to one of respect for SARS-COV-2. This has been the consequence of the integral study of all the dimensions of the disease, from viral recombinant capacity to transmissibility, diagnosis, care and prevention. This document summarizes the main strategic lines of study and approach to the pandemic in Madrid.

Designing Hyperchaos and Intermittency in Semiconductor Superlattices.

Weakly coupled semiconductor superlattices under dc voltage bias are excitable systems with many degrees of freedom that may exhibit spontaneous chaos at room temperature and act as fast physical random number generator devices. Superlattices with identical periods exhibit current self-oscillations due to the dynamics of charge dipole waves but chaotic oscillations exist on narrow voltage intervals. They disappear easily due to variation in structural growth parameters. Based on numerical simulations, we predict that inserting two identical sufficiently separated wider wells increases superlattice excitability by allowing wave nucleation at the modified wells and more complex dynamics. This system exhibits hyperchaos and varieties of intermittent chaos in extended dc voltage ranges. Unlike in ideal superlattices, our chaotic attractors are robust and resilient against noises and against controlled random disorder due to growth fluctuations.