Simulation of the electrical stimulation of the rat brain using sleep frequencies: A finite element modeling approach.

A realistic rat brain model was used to simulate current density and electric field distributions under frequencies characteristic of sleeping states (0.8, 5, and 12 Hz). Two anode-electrode setups were simulated: plate vs. screws-anode, both with a cephalic cathode. Our simulations showed that these frequencies have limited impact on electric field and current density; however, the highest frequency evidenced higher values for both variables. The type of electrode setup had a greater effect on current distribution and induced fields. In that sense, the screws setup resulted in higher values of the modeled variables. The numeric results obtained are within the range of available data for rodent models using the finite elements method. These modeled effects should be analyzed regarding anatomical consequences (depth of penetration of the currents) and purpose of the experiment (i.e., entrainment of brain oscillations) in the context of sleep research.

Distances of transmission risk of COVID-19 inside dwellings and evaluation of the effectiveness of reciprocal proximity warning sounds.

One of the main modes of transmission and propagation of COVID-19 (SARS-CoV-2) is the direct contact with respiratory droplets transmitted among individuals at a certain distance. There are indoor spaces, such as dwellings, in which the transmission risk is high. This research aims to record and analyze risk close contacts in this scope, experimentally assessing the effectiveness of using electronic proximity warning sound devices or systems. For this purpose, the methodology is based on monitoring the location of the occupants of a dwelling. Then, the days in which a proximity warning sound system is installed and activated are compared to the days in which the system is not activated. The results stressed the significant reduction of time and number of close contacts among individuals when the warning was activated. Regarding the relation between the number and the duration of close contacts, together with the reductions mentioned, the possibility of making certain predictions based on the distributions obtained is proved. All this contributes to the progress in the prevention of COVID-19 transmission because of close contacts in dwellings.

Differential IL 10 serum production between an arm-based and a leg-based maximal resistance test.

Bench press (i.e. arm-based) and half-squat (i.e. leg-based) are exercises commonly used to increase and evaluate muscular strength. In addition to differences in the location of the muscles that participate in each exercise, the total muscle mass required for the latter is larger than that involved in the former. The aim of this study is to analyze the effects of a maximal incremental strength test when performed by bench press and by half-squat on myocellular damage, oxidative damage and the inflammatory cytokine response. Ten male athletes were subjected to half-squat and bench press incremental strength tests. Blood samples were collected at rest, 15-minutes and 24 h post-test. Hydroperoxide and malondialdehyde concentrations were determined as lipid peroxidation markers. Lactate dehydrogenase (LDH) and creatine kinase isoenzyme MB (CK-MB) activities were determined as markers of muscle damage. α-Actin concentration was determined as a marker of sarcomeric damage. Serum interleukin (IL) 6, IL10, and tumor necrosis factor alpha (TNFα) were determined to assess the inflammatory response. LDH and CK-MB values were greater at 15 min and 24 h post bench press exercise (p < 0.05). No differences were found in lipid peroxidation or α-actin. Interestingly, IL10 values were greater in response to the press bench at 24 h post-test (p < 0.05). Our results suggest that, at equivalent workloads, an arm-based exercise induced higher anti-inflammatory effects and more severe muscle damage compared with a leg-based exercise.

Psychological well-being among older adults during the COVID-19 outbreak: a comparative study of the young-old and the old-old adults.

The COVID-19 outbreak could be considered as an uncontrollable stressful life event. Lockdown measures have provoked a disruption of daily life with a great impact over older adults' health and well-being. Nevertheless, eudaimonic well-being plays a protective role in confronting adverse circumstances, such as the COVID-19 situation. This study aims to assess the association between age and psychological well-being (personal growth and purpose in life). Young-old (60-70 years) and old-old (71-80 years) community-dwelling Spaniards (N = 878) completed a survey and reported on their sociodemographic characteristics and their levels of health, COVID-19 stress-related, appraisal, and personal resources. Old-old did not evidence poorer psychological well-being than young-old. Age has only a negative impact on personal growth. The results also suggest that the nature of the COVID-19 impact (except for the loss of a loved one) may not be as relevant for the older adults' well-being as their appraisals and personal resources for managing COVID-related problems. In addition, these results suggest that some sociodemographic and health-related variables have an impact on older adults' well-being. Thus, perceived-health, family functioning, resilience, gratitude, and acceptance had significant associations with both personal growth and purpose in life. Efforts to address older adults' psychological well-being focusing on older adults' personal resources should be considered.

Comparison of the inflammatory and stress response between sprint interval swimming and running.

The aim of the study was to compare myocellular damage, metabolic stress, and inflammatory responses as well as circulating sodium (Na+ ) and potassium (K+ ) between a single sprint swimming and running training. Eighteen subjects regularly involved in swimming and running training for at least 2 years were recruited. The subjects performed 8 × 30 seconds "all out" exercise on different days either by running or by swimming in a random order. Blood was collected before each training session, after the cessation of exercise (post) and after 2 hours of rest (2 hours). We then analyzed tumor necrosis factor alpha (TNF-α), interleukin 10 (IL-10), interleukin 6 (IL-6), cortisol, creatine kinase MB isoform (CK-MB), lactate dehydrogenase (LDH), K+ , and Na+ . Neither TNF-α nor IL-10 differed between swimming and running. Most of the subjects showed a non-statistically significant increase of LDH and CK-MB after swimming. On the other hand, IL-6 (P < .05) and cortisol (P < .05) were significantly lower after 2 hours of swimming than after running. In addition, post-exercise K+ was significantly lower (P < .001) for swimming than for running. Our results provide evidence of similar inflammatory responses between exercise modes but lower metabolic stress in response to swimming than in response to running.

Human enteric viruses in a wastewater treatment plant: evaluation of activated sludge combined with UV disinfection process reveals different removal performances for viruses with different features.

This study assess the quality of wastewater through the detection and quantification of important viruses causing gastroenteritis at different stages of the wastewater treatment process in an activated-sludge wastewater treatment plant with ultraviolet disinfection. Ten sampling events were carried out in a campaign along a period of 18 months collecting wastewater samples from the influent, after the activated-sludge treatment, and after the final disinfection with UV radiation. Samples were concentrated through ultracentrifugation and analysed using retro-transcription, PCR and real time quantitative PCR protocols, for detection and quantification of Group A Rotavirus (RVA), Human Astrovirus (HAstV), Norovirus Genogroup II (NoV GII) and Human Adenovirus (HAdV). HAdV (100%), NoV GII (90%), RVA (70%) and HAstV (60%) were detected in influent samples with concentration from 1·4 (NoV GII) to 8·0 (RVA) log10  gc l-1 . Activated-sludge treatment reached well quality effluents with low organic material concentration, although nonstatistical significant differences were registered among influent and postactivated sludge treatment samples, regarding the presence and concentration for most viruses. All post-UV samples were negative for NoV GII and HAstV, although RVA and HAdV were detected in 38% and 63% of those samples respectively, with concentration ranging from 2·2 to 5·5 and 3·1 to 3·4 log10  gc l-1 . SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates that an activated-sludge wastewater treatment plant with UV disinfection reduces to levels below the detection limit those single-stranded RNA viruses as noroviruses and astroviruses and reach significant lower levels of rotaviruses and adenoviruses after the complete treatment process.

LEACHING AND DEGRADATION OF 2,4-DICHLOROPHENOXIACETIC ACID, IN COLOMBIA RICE FLOODED SOIL.

Rice is mostly cultivated on soil held under flooded conditions. Under these conditions pesticides undergo reductive transformations which are characteristic to rice fields and other anaerobic systems. The present study was undertaken to evaluate the mobility and persistence of 2,4-dichlorophenoxy acetic acid (2,4-D) under laboratory conditions for the rice crop in Espinal, Colombia. A displacement study was performed on a hand packed soil column 30 cm length. After leaching experiment, the soil from column was sliced into six successive sections (5 cm). Methanol acidified (H3PO4 0.25%) extraction was used to determine the herbicide residues in each section. 2,4-D experimental breakthrough curve was analyzed using Stanmod program (inverse problem) to obtain transport parameters. The non-equilibrium physical model fitted well the experimental breakthrough curve. The recovery percent of 2,4-D in leachates was 36.44% after 3.4 pore volumes, and retardation factor was 2.1, indicating low adsorption in that conditions. 2,4-D was rapidly degraded, with DT50 = 11.4 days. The results suggest that 2,4-D under flooded conditions have a high potential for leaching through the soil profile, although the elevated rate of degradation reduced the ground water contamination risk.

Manual scoring of periodic limb movements in children: is it still necessary?

OBJECTIVE: Although manual scoring has been classically considered the gold standard to identify periodic leg movements (PLM), it is a very time consuming and expensive process, also subject to variability in interpretation. In the last decades, different authors have observed reasonably good agreement between automated PSG scoring algorithms and manual scoring in adults, according to established criteria. We aim to compare the automatic software analysis of our polysomnogram with the manual staging in children with sleep-disordered breathing. METHODS: We performed a semiautomatic method, in which an experienced technician watched the video recording and removed from the automatic analysis those movements that did not correspond to true candidate leg movement (LM). RESULTS: A total of 131 PSGs were studied; applying the established criteria, 65 children were diagnosed of obstructive sleep apnea, and 66 presented snoring but with no sleep apnea. The mean age was 6.7 years (±1.7) and twenty-five children (19.08 %) had a PLMI >5/h. Statistical differences were found not only for PLMI (manual: 2.20 (0.7, 4.1) vs automatic (6.4 (3.85,9.5); p < 0.001), but for almost of all indexes assessed between the automatic and the manual scoring analysis. The level of concordance was only moderate for PLM index (0.63 [0.51-0.72]); showing that, unlike the articles published in the adult population, automatic analysis is not accurate in children and, manually or semi-automatically analysis as ours need to be done. CONCLUSION: It seems that PLM detection algorithm might work accurately but, the real need would be a true LM detection algorithm.

Effect of iodixanol and propylene glycol as clearing agents in extensor digitorum longus and soleus muscles: mechanical and morphological characterization using the optical coherence tomography technique.

Soft tissue engineering and regenerative medicine aim to address the intricate relationship between tissue architecture and biomechanical performance. The traditional technique used to analyze muscular architectures is histology. However, optical coherence tomography is a novel non-destructive, non-invasive imaging tool that provides real-time, high-resolution visualization of tissue microstructure, making it applicable to soft tissues. High-quality images, minimized light scattering, and different clearing agents, such as propylene glycol and iodixanol, have been employed. A stress-relaxation test was performed to characterize the effects of clearing agents on rat extensor digitorum longus and soleus muscles. Additionally, muscle fiber structure images obtained using optical correlation tomography were compared with histological images to corroborate the high precision of the optical method. The results showed that iodixanol is a promising clearing agent for characterizing muscles as it provides good quality images and a satisfactory reversibility process with no permanent damage to the extracellular matrix or muscle fiber structure of the tissue.

Duchenne and Becker muscular dystrophy: Cellular mechanisms, image analysis, and computational models: A review.

The muscle is the principal tissue that is capable to transform potential energy into kinetic energy. This process is due to the transformation of chemical energy into mechanical energy to enhance the movements and all the daily activities. However, muscular tissues can be affected by some pathologies associated with genetic alterations that affect the expression of proteins. As the muscle is a highly organized structure in which most of the signaling pathways and proteins are related to one another, pathologies may overlap. Duchenne muscular dystrophy (DMD) is one of the most severe muscle pathologies triggering degeneration and muscle necrosis. Several mathematical models have been developed to predict muscle response to different scenarios and pathologies. The aim of this review is to describe DMD and Becker muscular dystrophy in terms of cellular behavior and molecular disorders and to present an overview of the computational models implemented to understand muscle behavior with the aim of improving regenerative therapy.

Numerical approximation to the effects of the atmospheric stability conditions on the dispersion of pollutants over flat areas.

Using the Computational Fluid Dynamics technique (CFD), we explored the effects of the atmospheric stability conditions on the dispersion of solid and gas-phase pollutants emitted from an area source located on a flat region. As an application, the dispersion of pollutants emitted from roads located on flat terrains was considered. Toward that end, we set up a model that describes the dispersion of air pollutants in a small region (< 1 km long) near the ground surface (< 250 m high). It consists of a neutrally stratified model modified to account for the atmospheric stability effects by imposing the near-ground stratification through the Monin-Obukhov similarity theory and the k-ε turbulence model adjusted for each atmospheric stability condition. Using this model, we simulated the dispersion of pollutants emitted from the road and plotted the resulting downwind concentrations in terms of dimensionless numbers. Results from our CFD-based model were highly correlated (R2 > 0.95) with the SF6 concentrations measured downwind a line source of this trace gas by the U.S. National Oceanic Atmospheric Administration in 2008 under different conditions of atmospheric stability. Numerical and experimental results showed that, under any of the stability conditions explored, the near-road pollutant concentrations are highly correlated (R2 > 0.87) to the concentrations observed under neutral conditions. When the atmosphere is extremely stable, those concentrations were up to 12 times higher than those observed under neutral conditions. We report the constant of proportionality obtained for every stability condition.

Paradoxical sleep: effect of low partial pressures of atmospheric oxygen.

When cats are subjected to an atmosphere of 100 percent oxygen at a sufficiently low pressure, their sleeping patterns are changed: paradoxical sleep disappears and drowsiness increases. This change appears when the pressure decreases to a level close to that at which the hemoglobin begins to dissociate. Return of a cat to a normal atmosphere produces a rebound: the cat spends more time in paradoxical sleep than it did during the base-line period. This finding suggests that a mechanism, closely related to the metabolism of oxygen in the brain, must play an important role in the production of paradoxical sleep. Yet the increase in paradoxical sleep after decompression indicates that still other mechanisms must merge to produce paradoxical sleep.

Gastrointestinal transit scintigraphy in chronic constipation evaluation in pediatric age; an infrequent test. / Gammagrafía de tránsito gastrointestinal en el estudio del estreñimiento crónico en edad pediátrica; una exploración infrecuente.

AIM: Chronic constipation is a common pathology in children. The aim of this paper was to show the usefulness of gastrointestinal transit scintigraphy in pediatric patients with chronic constipation, and the advantages with respect to other imaging techniques, despite our limited experience. MATERIAL AND METHODS: We evaluated 5 patients sent to our service with a diagnosis of chronic constipation refractory to treatment. We performed a complete study protocol, including liquid gastric emptying scintigraphy and small and large bowel transit times, using a single dose of 111In-DTPA. Following international guidelines regions of interest were defined in stomach, terminal ileum and in 6 regions of the large intestine. RESULTS: All patients showed altered scintigraphy study, showing 4 of them normal radiological tests. Radioisotopic study changed diagnosis in 2 patients and in other 2 patients contributed to clarify it, since discordance between normal radiological tests and abnormal rectal biopsy. One of the patients showed concordance between each imaging modality. The results of the test changed the therapeutic management in 2 cases. CONCLUSIONS: Our limited experience coincides with published data in which scintigraphy study turns out to be a reproducible and accurate method. It provides physiological, quantitative and useful information in the study of constipation, being the unique exploration that allows both global and regional gastrointestinal transit time determination.

Antioxidant effect of exercise: Exploring the role of the mitochondrial complex I superassembly.

Mitochondrial respiratory complexes become assembled into supercomplexes (SC) under physiological conditions. One of the functional roles of these entities is the limitation of reactive oxygen species (ROS) produced by complex I (CI) of the respiratory chain. We sought to determine whether the systemic antioxidant effect of exercise is mediated by the assembly of mitochondrial CIs into SCs in rats. Male Wistar rats were exercise trained or remained sedentary for ten weeks; then, blood samples were collected, and the gastrocnemius muscle was isolated. The assembly of mitochondrial SCs and the lipid peroxidation of the mitochondrial and plasmatic fractions were assessed. Our results demonstrate that exercise induced the assembly of CI into SCs in the gastrocnemius and induced a systemic decrease in lipid peroxidation. We also found an inverse association between the superassembly of CIs and mitochondrial lipid peroxidation (p < 0.01) and protein carbonyls (p < 0.05). We conclude that exercise induces the chronic assembly of CIs into SCs, which provide mitochondrial protection against oxidative damage, at least in the studied muscle. Given the relevant role that mitochondria play in health and disease, these findings should help to elucidate the role of exercise as a therapeutic approach for metabolic diseases.

Coenzyme Q content depends upon oxidative stress and dietary fat unsaturation.

The presence of Coenzyme Q (CoQ) in food, its role in cellular bioenergetics and antioxidant protection and the key role played by dietary fatty acids on membrane structure support the interest for a wide research concerning the relationship between dietary fats, CoQ content and biochemical behaviour. Several models of peroxidative stress 'in vivo' have been extensively investigated in our laboratory, with particular regards to the influence of dietary fat upon mitochondrial CoQ levels. First studies showed that the unsaturation degree of dietary fat leads to different CoQ9 and CoQ10 mitochondrial contents. The highest levels were found using polyunsaturated fat. A significant CoQ9 decrease after adriamycin peroxidative induction was found when dietary fat was polyunsaturated; on the contrary, a light increase was found in the case of monounsaturated fat. Another example of oxidative stress is that produced by food frying. The results obtained were in some cases similar to those of the previous experimental design: in fact monounsaturated dietary fats increased CoQ mitochondrial contents, whereas the polyunsaturated ones decreased CoQ levels. Finally, the combined effect of physical exercise and dietary fats on tissue and plasma CoQ levels has been studied. CoQ levels did not change during aerobic performances when dietary fat was monounsaturated whereas light increases were detected in the case of polyunsaturated fats. On the contrary, in anaerobic conditions, CoQ levels clearly increased with monounsaturated fats and no alterations were found in the case of polyunsaturated ones.

An updating of the biochemical function of coenzyme Q in mitochondria.

The apparent Km for coenzyme Q10 in NADH oxidation by coenzyme Q (CoQ)-extracted beef heart mitochondria is close to their CoQ content, whereas both succinate and glycerol-3-phosphate oxidation (the latter measured in hamster brown adipose tissue mitochondria) are almost saturated at physiological CoQ concentration. Attempts to enhance NADH oxidation rate by excess CoQ incorporation in vitro were only partially successful: the reason is in the limited amount of CoQ10 that can be incorporated in monomeric form, as shown by lack of fluorescence quenching of membrane fluorescent probes; at difference with CoQ10, CoQ5 quenches probe fluorescence and likewise enhances NADH oxidation rate above normal. Attempts to enhance the CoQ content in perfused rat liver and in isolated hepatocytes failed to show uptake in the purified mitochondrial fraction. Nevertheless CoQ cellular uptake is able to protect mitochondrial activities. Incubation of hepatocytes with adriamycin induces loss of respiration and mitochondrial potential measured in whole cells by flow cytometry using rhodamine 123 as a probe: concomitant incubation with CoQ10 completely protects both respiration and potential. An experimental study of aging in the rat has shown some decrease of mitochondrial CoQ content in heart, and less in liver and skeletal muscle. In spite of the little change observed, it is reasoned that CoQ administration may be beneficial in the elderly, owing to the increased demand for antioxidants.

Peroxidative extent and coenzyme Q levels in the rat: influence of physical training and dietary fats.

Sport practice is widely recognized as capable of producing peroxidative damages, even of severe intensity. Dietary manipulations can also modify membrane susceptibility to peroxidation. In previous experiments we found that, while dietary virgin olive oil successfully protects mitochondrial and microsomal membranes from endogenous, xenobiotics-induced peroxidation, dietary polyunsaturated oils lead to increased peroxidative levels. In the latter conditions, cell machinery tries to counteract the structural and functional changes which have occurred, by modulating enzyme activities and concentrations, by increasing biosynthesis of coenzyme Q and by mobilizing cholesterol. In the present study we hypothesized that combining these two aspects could give useful information on the membrane response to peroxidation phenomena that daily occur throughout the lifespan. Rats fed different dietary oils as only fat source underwent a carefully designed training program and were killed at different times following acute or chronic exercise. Results show that peroxidation related to chronic training and to an acute bout of exercise sum up with peroxidative effects induced by dietary factors. The above mentioned phenomena occurred simultaneously with increased tissue levels of coenzyme Q, possibly triggered within a physiological reactive antioxidant strategy.

Lipid peroxidation and antioxidants in newborns.

The aim of this investigation was to elucidate a possible correlation between lipid peroxidation, antioxidant concentrations and erythrocyte membrane fluidity in plasma from newborns. Ten healthy newborns were recruited. Venous blood samples were collected at birth, and thereafter at 3 and 72 h postnatal age. The following parameters were assessed: hydroperoxides, Coenzyme Q10 and alpha-tocopherol both in plasma and in erythrocyte membranes, and fluorescence polarization (as a tool for assessing membrane fluidity). Hydroperoxides were shown to be high in erythrocyte membranes at birth and significantly decreased at 3 and 72 h after birth. In the erythrocyte membranes, coenzyme Q10 content showed an opposite behaviour with respect to the plasma compartment. Membrane fluidity appeared unchanged even in the presence of the above mentioned modifications.

Changes in mitochondrial and microsomal rat liver coenzyme Q9 and Q10 content induced by dietary fat and endogenous lipid peroxidation.

The influence of different kinds of dietary fat (8%) and of endogenous lipid peroxidation with regard to coenzyme Q9 (CoQ9) and coenzyme Q10 (CoQ10) concentrations in mitochondria and microsomes from rat liver has been investigated by means of an HPLC technique. Although the different diet fats used did not produce any effect on microsomes, it was possible to show that each experimental diet differently influenced the mitochondrial levels of CoQ9 and CoQ10. The highest mitochondrial CoQ content was found in case of a diet supplemented with corn oil. An endogenous oxidative stress induced by adriamycin was able to produce a sharp decrease in mitochondrial CoQ9 levels in the rats to which corn oil was administered. The results suggest that dietary fat ought to be considered when studies concerning CoQ mitochondrial levels are carried out.