Effect of crowding on the electron transfer process from plastocyanin and cytochrome c6 to photosystem I: a comparative study from cyanobacteria to green algae

Plastocyanin and cytochrome c 6, the alternate donor proteins to photosystem I, can be acidic, neutral or basic; the role of electrostatics in their interaction with photosystem I vary accordingly for cyanobacteria, algae and plants. The effect of different crowding agents on the kinetics of the reaction between plastocyanin or cytochrome c 6 and photosystem I from three different cyanobacteria, Synechocystis PCC 6803, Nostoc PCC 7119 and Arthrospira maxima, and a green alga, Monoraphidium braunii, has been investigated by laser flash photolysis, in order to elucidate how molecular crowding affects the interaction between the two donor proteins and photosystem I. The negative effect of viscosity on the interaction of the two donors with photosystem I for the three cyanobacterial systems is very similar, as studied by increasing sucrose concentration. Bovine serum albumin seems to alter the different systems in a specific way, probably by means of electrostatic interactions with the donor proteins. Ficoll and dextran behave in a parallel manner, favouring the interaction by an average factor of 2, although this effect is somewhat less pronounced in Nostoc. With regards to the eukaryotic system, a strong negative effect of viscosity is able to overcome the favourable effect of any crowding agent, maybe due to stronger donor/photosystem I electrostatic interactions or the structural nature of the eukaryotic photosystem I-enriched membrane particles.Spanish Ministry of Innovation and Science BFU2006-01361Andalusian Government PAI BIO-02

Significado patológico de la imagen ultrasónica en pequeños animales

La ecografía es una técnica de diagnóstico por imagen segura, no invasiva y que no requiere una preparación excesiva del animal. Se utiliza para estudiar tejidos blandos, permitiendo la valoración del tamaño, forma, situación y estructura de los mismos. La ecografía o ultrasonografía se basa en los ultrasonidos generados en un dispositivo llamado transductor, compuesto por cristales piezoeléctricos. La Histopatología constituye un medio diagnóstico especializado, complementario de otras técnicas diagnósticas como la ecografía y que, en la mayoría de los casos, resulta esencial en cuanto a establecer un diagnóstico definitivo en muchos procesos patológicos. La toma de biopsias para realizar un estudio histopatológico requiere una acción agresiva “in vivo” sobre el animal pudiendo servirse de la técnica ecográfica para realizar la toma de muestras de los diferentes órganos internos. El objetivo de este trabajo es el establecimiento de una correlación directa entre la imagen ultrasónica de órganos normales y patológicos procedentes de animales eutanasiados o de extirpaciones quirúrgicas de rutina, con la imagen macroscópica e histopatológica de esos mismos órganos.Ultrasound is a diagnostic imaging technique safe, non invasive and does not require excessive grooming of the animal. Is used to study soft tissue, allowing the assessment of the size, shape, location and structure of the data. Ultrasound sonography, based on the ultrasound generated in a device called a transducer, comprising crystals piezoeléctricos. La constitutes a diagnostic Histopathology specialized complementary to other diagnostic techniques such as ultrasound and that, in most cases, it is essential as for a defi nitive diagnosis in many disease processes. The biopsy for histopathological study requires aggressive action “in vivo” on the animal can use ultrasound technique for sampling of the different organs internos. The aim of this study is to establish a direct correlation between the ultrasound image of normal and pathological organs from animals euthanized or routine surgical excision with macroscopic images and histopathologyf these same organs

Análisis de los factores de riesgo asociados a reingreso en pacientes con cirrosis hepática

Introducción: La cirrosis hepática descompensada es una causa frecuente de reingreso hospitalario a 30, 60 y 90 días con una tasa que alcanza el 31,4 %, muy por encima del 11%-14% que es la media de cualquier otra causa. Se han identificado como factores predictivos de reingreso: sexo masculino, puntuación MELD elevada, sodio sérico e índice de Charlson. Objetivo: Describir los motivos de ingreso e identificar los factores de riesgo asociados a reingreso precoz (a 30 días), a 60 y 90 días en una cohorte de pacientes con cirrosis hepática descompensada en el Hospital de Manises. Material y métodos: Estudio observacional, descriptivo, longitudinal y retrospectivo de los pacientes con cirrosis hepática descompensada hospitalizados en el Hospital de Manises entre enero y diciembre de 2021. Se recogieron variables demográficas, clínicas y analíticas relativas a la hepatopatía en el ingreso y reingreso. Resultados: 82,4% varones, mediana edad: 64 años. Principal etiología de la cirrosis: alcohol (78,5%). 17 pacientes reingresaron durante el periodo de estudio: 7 en ≤30 días, 4 entre 31-60 y 2 entre 61-90. El principal motivo de reingreso fue la por descompensación hidrópica (21,6%), seguida de HDA 5,9%, la encefalopatía 3,9% y la ictericia 2%. 4 pacientes fallecieron durante el estudio (7,8%). La PBE se asoció a reingreso precoz (OR 0,18; IC 95% 0,10-0,32; p = 0,041). Conclusiones: Se observó una tasa de reingreso precoz del 19,6%. La PBE fue el único factor que se asoció a reingreso precoz.Background: Decompensated liver cirrhosis is a frequent cause of hospital readmission at 30, 60 and 90 days with a rate that reaches 31.4%, well above the 11%-14% which is the average of any other cause. Male sex, high MELD score, serum sodium and Charlson index have been identified as predictive factors for readmission. Aim: To describe the reasons for admission and to identify the risk factors associated with early readmission (at 30 days), at 60 and 90 days in a cohort of patients with decompensated liver cirrhosis at the Manises Hospital. Methods: Observational, descriptive, longitudinal and retrospective study of patients with decompensated liver cirrhosis hospitalized at the Manises Hospital between January and December 2021. Demographic, clinical and analytical variables related to liver disease were collected at admission and readmission. Results: 82.4% were male, with a median age of 64 years. The main etiology of cirrhosis was alcohol (78.5%). 17 patients were readmitted during the study period: 7 in ≤30 days, 4 between 31-60 and 2 in 61-90. The main reason for readmission was hydropic decompensation (21.6%), followed by variceal bleeding 5.9%, encephalopathy 3.9% and jaundice 2%. 4 patients died during the study (7.8%). SPB was associated with early readmission (OR 0,18; CI 95% 0,10-0,32; p = 0,041). Conclusions: A readmission rate of 19.6% was observed. SPB was the only factor associated with early readmission.Medicin

A Proposal for a Benchmark Generator of Weakly Connected Directed Graphs

[EN] The previous studies on detection of communities on complex networks were focused on nondirected graphs, such as Neural Networks, social networks, social interrelations, the contagion of diseases, and bibliographies. However, there are also other problems whose modeling entails obtaining a weakly connected directed graph such as the student access to the university, the public transport networks, or trophic chains. Those cases deserve particularized study with an analysis and the resolution adjusted to them. Additionally, this is a challenge, since the existing algorithms in most of the cases were originally designed for non-directed graphs or symmetrical and regular graphs. Our proposal is a Benchmark Generator of Weakly Connected Directed Graphs whose properties can be defined by the end-users according to their necessities. The source code of the generators described in this article is available in GitHub under the GNU license.This work has been supported by the Project "Complex Networks" from the Instituto Universitario de Matemática Multidisciplinar (IUMM) of the Universitat Politècnica de València (UPV) [under Grant number (266500194) 20170251- Complex-Networks-UPV].Montañana, JM.; Hervás, A.; Soriano Jiménez, PP. (2020). A Proposal for a Benchmark Generator of Weakly Connected Directed Graphs. Open Journal of Modelling and Simulation. 8(1):18-34. https://doi.org/10.4236/ojmsi.2020.8100218348

A procedure for detection of border communities using convolution techniques

[EN] Many complex systems can be modeled by graphs and networks, [4]. In some problems, the study of communities allows quantitative and qualitative approaches and obtaining some knowledge about the structure of the graph and what it represents [1, 3, 5]. There is extensive literature in the study of communities, mostly focused on non-directed graphs [3, 5]. In our case we focus our work on the study of communities in directed graphs, weakly connected, with weights on the edges. In MME&HB 2016, was presented an algorithm for detection of directional communities in a directed graph [1], with a special interest in the graph representing the process of access to the Spanish Public University System, (SUPE) [1, 2]. The proposed algorithm allowed to obtain communities that provided an approximation to the problem. In MME&HB 2020 we propose a new algorithm based on obtaining the centers of the graph and pruning non-significant edges [6]. Recently a method for obtain communities using convolution techniques was presented in [5]. In this paper, we propose a community detection algorithm that combines a method for calculating potential community centers and convolution techniques to prune non-significant edges.Montañana, JM.; Hervás, A.; Morillas, S.; Soriano Jiménez, PP. (2021). A procedure for detection of border communities using convolution techniques. Universitat Politècnica de València. 267-271. http://hdl.handle.net/10251/19055926727

Cyt c6-3: A new isoform of photosynthetic Cyt c6 exclusive to heterocyst-forming cyanobacteria

All known cyanobacteria contain Cyt c6, a small soluble electron carrier protein whose main function is to transfer electrons from the Cyt b6 f complex to PSI, although it is also involved in respiration. We have previously described a second isoform of this protein, the Cyt c6-like, whose function remains unknown. Here we describe a third isoform of Cyt c6 (here called Cytc6-3), which is only found in heterocyst- forming filamentous cyanobacteria. Cyt c6-3 is expressed in vegetative cells but is specifically repressed in heterocysts cells under diazotrophic growth conditions. Although there is a close structural similarity between Cyt c6-3 and Cyt c6 related to the general protein folding, Cyt c6-3 presents differential electrostatic surface features as compared with Cyt c6, its expression is not copper dependent and has a low reactivity towards PSI. According to the different expression pattern, functional reactivity and structural properties, Cyt c6-3 has to play an as yet to be defined regulatory role related to heterocyst differentiation.Fundación de Investigación de la Universidad de Sevilla FIUS05710000Ministerio de Economía y Competitividad BIO2012-35271, BIO2015-64169-PJunta de Andalucía PAIDI BIO-02

Feature selection to enhance a two-stage evolutionary algorithm in product unit neural networks for complex classification problems

This paper combines feature selection methods with a two-stage evolutionary classifier based on product unit neural networks. The enhanced methodology has been tried out with four filters using 18 data sets that report test error rates about 20 % or above with reference classifiers such as C4.5 or 1-NN. The proposal has also been evaluated in a liver-transplantation real-world problem with serious troubles in the data distribution and classifiers get low performance. The study includes an overall empirical comparison between the models obtained with and without feature selection using different kind of neural networks, like RBF, MLP and other state-of-the-art classifiers. Statistical tests show that our proposal significantly improves the test accuracy of the previous models. The reduction percentage in the number of inputs is, on average, above 55 %, thus a greater efficiency is achieved.MICYT TIN2007-68084- C02-02MICYT TIN2008-06681-C06-03MICYT TIN2011-28956-C0

Multilogistic Regression using Initial and Radial Basis Function covariates

This paper proposes a hybrid multilogistic model, named MultiLogistic Regression using Initial and Radial Basis Function covariates (MLRIRBF). The process for obtaining the coefficients is carried out in several steps. First, an Evolutionary Programming (EP) algorithm is applied, aimed to produce a RBF Neural Network (RBFNN) with a reduced number of RBF transformations and the simplest structure possible. Then, the input space is transformed by adding the nonlinear transformations of the input variables given by the RBFs of the best individual in the last generation. Finally, a maximum likelihood optimization method determines the coefficients associated with a multilogistic regression model built on this transformed input space. In this final step, two different multilogistic regression algorithms are applied, one that considers all initial and RBF covariates (MLRIRBF) and another one that incrementally constructs the model and applies cross-validation, resulting in an automatic covariate selection (MLRIRBF*). The methodology proposed is tested using six benchmark classification problems from well-known machine learning problems. The results are compared with the corresponding multilogistic regression methodologies applied over the initial input space, to the RBFNNs obtained by the EP algorithm (RBFEP) and to other competitive machine learning techniques. The MLRIRBF* models are found to be better than the corresponding multilogistic regression methodologies and the RBFEP method for almost all datasets, and obtain the highest mean accuracy rank when compared to the rest of methods in all datasets

Electron Transfer Pathways and Dynamics of Chloroplast NADPH-dependent Thioredoxin Reductase C (NTRC)

NADPH-dependent thioredoxin reductases (NTRs) contain a flavin cofactor and a disulfide as redox-active groups. The catalytic mechanism of standard NTR involves a large conformational change between two configurations. Oxygenic photosynthetic organisms possess a plastid-localized NTR, called NTRC, with a thioredoxin module fused at the C terminus. NTRC is an efficient reductant of 2-Cys peroxiredoxins (2-Cys Prxs) and thus is involved in the protection against oxidative stress, among other functions. Although the mechanism of electron transfer of canonical NTRs is well established, it is not yet known in NTRC. By employing stopped-flow spectroscopy, we have carried out a comparative kinetic study of the electron transfer reactions involving NTRC, the truncated NTR module of NTRC, and NTRB, a canonical plant NTR. Whereas the three NTRs maintain the conformational change associated with the reductive cycle of catalysis, NTRC intramolecular electron transfer to the thioredoxin module presents two kinetic components (kET of ∼2 and 0.1 s−1), indicating the occurrence of additional dynamic motions. Moreover, the dynamic features associated with the electron transfer to the thioredoxin module are altered in the presence of 2-Cys Prx. NTRC shows structural constraints that may locate the thioredoxin module in positions with different efficiencies for electron transfer, the presence of 2-Cys Prx shifting the conformational equilibrium of the thioredoxin module to a specific position, which is not the most efficien

Assessment of Spanish Food Consumption Patterns during COVID-19 Home Confinement

People’s eating habits and lifestyle can have a negative impact on health. In situations of difficulty or socioeconomic crisis, these habits tend to be modified, leading to unhealthy dietary patterns that result in an increase of chronic non-communicable diseases (NCDs). Previous studies have indicated that, due to the state of alarm imposed in Spain to combat the spread of COVID-19, an increase in the purchase of non-core products occurred, along with a decrease in the daily physical activity of the population. This could be a risk factor for COVID-19 infection. The objective of this observational study was to analyze the dietary pattern of the Spanish population during home confinement and to compare it with the pattern of habitual consumption collected in the last National Health Survey, analyzing the possible changes. More than half of the respondents in the sample increased their consumption of sweets and snacks during confinement, while the consumption of fresh products decreased. Most claimed to be emotionally hungry, leading to an increase in their daily energy intake. The stress and anxiety generated by confinement could be the cause of the increased consumption of products rich in sugars and saturated fats, which are associated with greater stress and anxiety