Tunable structure of TiO2 deposited by DC magnetron sputtering to adsorb Cr (VI) and Fe (III) from water.

TiO2 thin films with mixtures of the anatase, rutile, and brookite phases were deposited on glass substrates via magnetron sputtering. Based on XRD and Raman results, the TiO2-0.47 and TiO2-3.47 films principally contained the brookite phase, while the TiO2-1.27 and TiO2-2.13 films were primarily anatase. The capacities of the TiO2 films to adsorb heavy metals were tested with Cr(VI) and Fe(III) solutions, and the maximum Cr(VI) and Fe(III) adsorption capacities were realized with the TiO2-0.47 film (334.5 mg/g) and TiO2-3.47 film (271.3 mg/g), respectively. SEM‒EDS results revealed the presence of Cr and Fe on the surfaces of the films, thus corroborating the ability of the TiO2 films to adsorb and remove heavy metals. They are strong candidates for use in wastewater treatment plants.

Incidence, prognosis, and prediction of haemorrhagic transformation after revascularisation for stroke.

INTRODUCTION: Haemorrhagic transformation is a major complication of acute ischaemic stroke (AIS). We sought to determine the predictors and clinical impact of intracranial haemorrhage (ICH) after revascularisation therapy. METHODS: We conducted a retrospective, single-centre study including 235 patients with AIS who underwent intravenous recombinant tissue plasminogen activator (IV-rtPA) therapy and/or endovascular treatment. A binary logistic regression model was used to determine the variables associated with ICH, parenchymal haematomas (PH), modified Rankin Scale (mRS) scores, and mortality. RESULTS: ICH was detected in 57 (30 with PH) of 183 patients included. Mechanical thrombectomy, either alone (OR 3.3 [1.42-7.63], P=.005) or in combination with IV-rtPA (OR 3.39 [1.52-7.56], P=.003), was associated with higher risk of ICH, while higher Alberta Stroke Program Early CT scores (OR 0.71 [0.55-0.91], P=.007) were associated with lower risk. Patients with older age (OR 1.07 [1.02-1.13], P=.006) and occlusion of the terminal branch of the internal carotid artery (OR 4.03 [1.35-11.99], P=.012) had a higher risk of PH, while the use of IV-rtPA alone (OR 0.24 [0.08-0.68], P=.008) was associated with lower risk of PH. Only PH was associated with disability as measured by the mRS (OR 3.2 [1.17-8.76], P=.02) and higher mortality (OR 5.06 [1.65-15.5], P=.005). CONCLUSIONS: Greater understanding about the predictors of ICH, mRS scores, and mortality could enable better selection of patients and treatments.

What does the freshwater clam, Corbicula largillierti, have to tell us about chlorothalonil effects?

Chlorothalonil (CLT) is a broad spectrum, and non-systemic fungicide applied in foliar structures to prevent and treat pathogens. This compound reaches to aquatic environments and affects the biota. In this context, the main goal of this study was to assess the effects of CLT at biochemical, tissular, and individual levels of biological organization using the invasive bivalve Corbicula largillierti as a bioindicator species. Clams were exposed to different sublethal concentrations (0, 10, 20 and 50 µg. L-1 CLT) for 96 h. At biochemical level, the enzymatic activity (Glutathione-s-Transferase, Catalase, Acetyl-, Butiryl- and Carboxyl-esterases) and lipid peroxidation were measured in gills and the visceral mass. Also, the digestive gland morphometry through quantitative histological indexes was registered at the tissular level. Finally, filtering activity and burial behavior at the individual level were measured. At the highest CLT concentration, the most significant changes were observed in enzymatic activity (except for butyrylcholinesterase), lipid peroxidation and in digestive gland morphometry. It was also registered increases of the filtering activity and the latency time to burial. Most of the biomarkers assessed showed significant responses under CLT exposure. Therefore, taking into account that C. largillierti was affected by CLT, it can be expected that other species could be in a potential risk if this fungicide is present in freshwater systems.

Treatment of posterior circulation strokes by mechanical thrombectomy with a stent-retriever: a retrospective observational study at a single center. / Tratamiento del ictus de circulación posterior mediante trombectomía mecánica con stent-retriever: un estudio observacional, monocéntrico y retrospectivo.

OBJECTIVES: To determine the rate of recanalization, functional outcome at three months, and independent prognostic factors in patients with posterior circulation strokes treated with stent-retrievers and to compare these results with those of patients in an earlier series treated with "classical methods". MATERIAL AND METHODS: This was a retrospective study of consecutive patients with posterior circulation strokes treated with stent-retrievers at our center between December 1, 2011 and May 1, 2018. The main outcome variables were the rate of recanalization according to the Thrombosis in Cerebral Infarction (TICI) scale and functional independence score 90 days after treatment according to the modified Rankin Scale (mRS). We analyzed demographics, cerebrovascular risk factors, clinical findings, and probable origin. Descriptive statistics and a binary logistic regression model were used to analyze the data. RESULTS: We included 75 patients: 27 treated with "classical methods" and 48 treated with stent-retrievers (10 women; mean age, 63.9 years; median National Institute of Health Stroke Score, 15.8 (IQR 9-25); median Glasgow Coma Scale (GCS), 9.1 (IQR 6-14,5). TICI 2b-3 recanalization was achieved in 46 (95.8%) patients treated with stent-retrievers and in 15 (55.6%) patients treated with "classical methods" (p<0.0001). No significant differences were observed in the rate of patients achieving mRS 0-2 at 90 days (19 (39.6%) of those treated with stent-retrievers vs. 6 (22.2%) of those treated with "classical methods"). Mortality was lower among patients treated with stent-retrievers (14 (29.2% vs. 15 (55.6%) in those treated with "classical methods", p=0.024). GCS score was independently associated with mRS at 90 days (OR:0.67; 95%CI:0.5-0.91; p=0.01). CONCLUSIONS: In patients with posterior circulation infarcts, treatment with stent-retrievers achieved high rates of recanalization and functional independence at 90 days. The rate of complications was similar to those reported in other studies. GCS is an independent predictor of functional independence at 90 days.

SHOX Duplication and Tall Stature in a Patient with Xq Deletion and Vascular Disease.

The anomalies of X chromosome are classified as numerical or structural. Concomitant structural anomalies in this chromosome that associate partial loss of its long arm with duplications in its short arm are uncommon. Only a few cases have been published and in most of them the reported patients present ovarian dysfunction, tall stature, and overdosage of the SHOX gene with locus Xp22.33. Considering these reports, we evaluated the case of a woman with a deletion in the long arm of the X chromosome, premature ovarian failure, tall stature, and multiple arterial vascular disease. With the aim to find a relationship between karyotype and phenotype, we explored associated anomalies in Xp and certified the overdosage of the SHOX gene in this case by MLPA. Also, taking into account the fact that the gene locus of the angiotensin-converting enzyme type 2 (ACE2) is located in Xp, our goal was to investigate the influence of this gene in the development of cardiovascular disease. The detection of the gene product of ACE2 by ELISA was undetectable. We have proposed that cytogenetic anomalies in X chromosome could contribute to decrease this protein synthesis in this gender.

Incidence, prognosis, and prediction of haemorrhagic transformation after revascularisation for stroke. / Incidencia, pronóstico y predicción de la transformación hemorrágica tras el tratamiento revascularizador del ictus.

INTRODUCTION: Haemorrhagic transformation is a major complication of acute ischaemic stroke (AIS). We sought to determine the predictors and clinical impact of intracranial haemorrhage (ICH) after revascularisation therapy. METHODS: We conducted a retrospective, single-centre study including 235 patients with AIS who underwent intravenous recombinant tissue plasminogen activator (IV-rtPA) therapy and/or endovascular treatment. A binary logistic regression model was used to determine the variables associated with ICH, parenchymal haematomas (PH), modified Rankin Scale (mRS) scores, and mortality. RESULTS: ICH was detected in 57 (30 with PH) of 183 patients included. Mechanical thrombectomy, either alone (OR 3.3 [1.42-7.63], P=.005) or in combination with IV-rtPA (OR 3.39 [1,52-7.56], P=.003), was associated with higher risk of ICH, while higher Alberta Stroke Program Early CT scores (OR 0.71 [0.55-0.91], P=.007) were associated with lower risk. Patients with older age (OR 1.07 [1.02-1.13], P=.006) and occlusion of the terminal branch of the internal carotid artery (OR 4.03 [1.35-11.99], P = .012) had a higher risk of PH, while the use of IV-rtPA alone (OR 0.24 [0.08-0.68], P=.008) was associated with lower risk of PH. Only PH was associated with disability as measured by the mRS (OR 3.2 [1.17-8.76], P=.02) and higher mortality (OR 5.06 [1.65-15.5], P=.005). CONCLUSIONS: Greater understanding about the predictors of ICH, mRS scores, and mortality could enable better selection of patients and treatments.

Intracranial stents in the endovascular treatment of acute ischemic stroke. / Uso del stent intracraneal en el tratamiento endovascular en agudo del ictus.

OBJECTIVE: To evaluate the efficacy and safety of intracranial stenting as a rescue therapy after failed mechanical thrombectomy in patients with acute ischemic stroke. MATERIAL AND METHODS: We retrospectively studied 42 patients treated with intracranial stenting after failed mechanical thrombectomy between December 2008 and January 2016. We compared outcomes before and after the incorporation of stentrievers. We assessed the degree of recanalization in the carotid and basilar territories (modified TIMI score), prognostic factors, and outcome (modified Rankin Score at 3 months). Safety was evaluated in function of the appearance of symptomatic intracranial hemorrhage (SICH). RESULTS: Median NIHSS was 17 in patients with carotid territory strokes and 26 in those with vertebrobasilar territory strokes. Median time from onset of symptoms to treatment was 225minutes in carotid territory strokes and 390minutes in vertebrobasilar territory strokes. A total of 10 patients underwent intravenous fibrinolytic therapy before treatment with stentrievers. Two patients developed SICH; both had undergone intravenous fibrinolytic therapy (p=0.0523). Recanalization was effective in 30 (71.4%) in the entire series: in 7 (50%) of 14 patients treated before the incorporation of stentrievers and in 23 (82.1%) of 28 treated after the incorporation of stentrievers (p=0.0666). Outcome at 3 months was good in 2 (14.3%) patients in the earlier group and in 14 (50%) patients in the later group (p=0.042). We found significant associations between recanalization and outcome (p=0.0415) and between shorter time to treatment and outcome (p=0.002). Outcome was good in 14 (48.3%) of the 29 patients with carotid territory strokes and in 2 (15.4%) of the 13 patients with vertebrobasilar territory strokes (p=0.078). CONCLUSIONS: Intracranial stenting is the rescue treatment when the usual treatment fails. Stentrievers must be used to eliminate the clot burden before stenting. In our study, antiplatelet treatment did not seem to increase the risk of SICH except in patients with prior intravenous fibrinolytic treatment.

Aerobic Fitness and Technical Efficiency at High Intensity Discriminate between Elite and Subelite Tennis Players.

The aim of this study was to determine whether selected physiological, performance and technical parameters derived from an on-court test are capable of discriminating between tennis players of national and international levels. 38 elite and subelite tennis players were divided into international level (INT, n=8) and national level players (NAT, n=30). They all performed a specific endurance field test, and selected physiological (maximum oxygen uptake [V˙O2max], and ventilatory thresholds [VT1 and VT2]), performance (test duration, final stage and hits per test) and technical (technical effectiveness [TE]) parameters were compared. INT showed greater V˙O2max, VO2 at VT2 (ml·kg(-1)·min(-1)), test duration (s), final stage (no.), hits per test (no.) and TE (% of successful hits), as compared with NAT (p<0.05). At high exercise intensity (stages 5 and 6), the INT achieved better TE than NAT (p=0.001-0.004), and the discriminant analyses showed that these technical parameters were the most discriminating factors. These results suggest that this specific endurance field test is capable of discriminating between tennis players at national and international levels, and that the better aerobic condition of the INT is associated with better technical efficiency at higher exercise intensities.

VO2 Kinetics in All-out Arm Stroke, Leg Kick and Whole Stroke Front Crawl 100-m Swimming.

The VO2 response to extreme-intensity exercise and its relationship with sports performance are largely unexplored. This study investigated the pulmonary VO2 kinetics during all-out 100-m front crawl whole stroke swimming (S), arm stroke (A) and leg kick (L). 26 male and 10 female competitive swimmers performed an all-out S trial followed by A and L of equal duration in random order. Breath-by-breath VO2 was measured using a snorkel attached to a portable gas analyzer. Mean (±SD) primary component parameters and peak blood lactate (Lapeak) during S, A, and L were, respectively: time delay (s), 14.2 ± 4.7, 14.3 ± 4.5, 15.6 ± 5.1; amplitude (ml·kg(-1)·min(-1)), 46.8 ± 6.1, 37.3 ± 6.9, 41.0 ± 4.7; time constant (τ, s): 9.2 ± 3.2, 12.4 ± 4.7, 10.1 ± 3.2; Lapeak (mmol·l(-1)), 6.8 ± 3.1, 6.3 ± 2.5, 7.9 ± 2.8. During A and L respectively, 80% and 87% of amplitude in S was reached, whereas A+L were 68% greater than in S. 100-m performance was associated to shorter cardiodynamic phase and greater VO2 amplitude and Lapeak (accounting up to 61% of performance variance), but not to τ. We conclude that (i) VO2 gain was proportional to exercise intensity and muscle mass involved, (ii) kicking is metabolically less efficient, and (iii) the main limiting factor of peak VO2 appears to be O2 delivery and not muscle extraction.

Intensity profile during an ultra-endurance triathlon in relation to testing and performance.

We examined the heart rate (HR)-based intensity profile during an ultra-endurance triathlon (UET) estimated from the individual HR-oxygen uptake (˙VO2) relationship during specific graded tests, relating it to race performance. 9 male ultra-endurance triathletes completed the study. Before racing, subjects performed graded exercise tests involving cycle (C) ergometry, treadmill running (R) and free swimming (S) for peak ˙VO2 and HR at ventilatory thresholds (VT). Exercise-specific HR-˙VO2 regression equations were developed. Mean race HR was higher during S (149.2 (10.1) bpm) than during C (137.1 (5.7) bpm) and R (136.2 (10.5) bpm). During C and R, HR was below both VT (11% and 27-28%). HR differences between S and C correlated with C, R and final times. The greatest differences between S and C were related to the worst times in the next stages. These ultra-endurance triathletes performed S at a higher relative intensity, which was inversely correlated with performance in the following stages. The best predictors of final racing time (81%) were weight-adjusted ˙VO2max and HR difference between C and S. A more adequate characterization of the time pattern during the whole race, especially during S, adds new information concerning the intensity profile and cardiovascular demands of an UET race.

Physiological demands of young women's competitive gymnastic routines.

The objective of this study was to investigate the physiological indices of competitive routines in women's artistic gymnastics by characterizing post-exercise heart rate (HR), oxygen uptake (VO2) and peak blood lactate concentration (Lmax) in a group of eight young elite-oriented female gymnasts. HR was continuously monitored with Polar RS400 monitors during the test event simulating a competition environment. Within 5 s of the end of each routine, the breath-by-breath gas analyser mask was placed on the face to record VO2. VO2max was calculated by the backward extrapolation method of the VO2 recovery curve. Lmax was obtained during recovery (min 1, 3, 5, 7 and 10) subsequent to each event. One week later, HR, VO2 and Lmax were measured during an incremental continuous treadmill test. The treadmill test was confirmed as the assessment with the highest physiological demand. The gymnasts reached their highest values of HR (183-199 beats · min(-1)), VO2/Bm (33-44 ml · kg(-1) · min(-1)) and Lmax (7-9 mmol · l(-1)) in the floor and uneven bars exercises. The vault was the event with the lowest HR (154-166 beats · min(-1)) and Lmax (2.4-2.6 mmol · l(-1)), and the balance beam had the lowest VO2 (27-35 ml · kg(-1) · min(-1)). The mean relative peak intensities attained in the different events, which ranged from 65 to 85% of the individual VO2max and HRmax recorded in the laboratory, suggest that cardiorespiratory and metabolic demands are higher than previously indicated. The high percentage of VO2 measured, particularly after the floor event, suggests that aerobic power training should not be neglected in women's artistic gymnastics.

Perceived exertion, time of immersion and physiological correlates in synchronized swimming.

This study examined the relationship between ratings of perceived exertion (RPE, CR-10), heart rate (HR), peak blood lactate (La peak), and immersion (IM) parameters in 17 elite synchronized swimmers performing 30 solo and duet routines during competition. All were video recorded (50 Hz) and an observational instrument was used to time the IM phases. Differences in the measured variables were tested using a linear mixed-effects model. RPE was 7.7 ± 1.1 and did not differ among routines, and neither did any of the HR parameters. There were differences among routines in La peak (F3,7=16.5; P=0.002), number of IM (F3,15=14.0; P<0.001), total time immersed (F3,16=26.6; P<0.001), percentage of time immersed (F3,13=6.5; P=0.007) and number of IM longer than 10 s (F3,19=3.0; P=0.04). RPE correlated positively to HR pre-activation, range of variation and recovery, IM parameters and La peak, and inversely to minimum and mean HR. A hierarchical multiple linear regression (MLR) model (number of IM >10 s, HR recovery, minimum HR, and La peak) explained 62% RPE variance (adj. Rm 2=0.62; P<0.001). A stepwise MLR model (La peak, mean IM time and pre-exercise HR) explained 46% of performance variance (adj. Rm 2=0.46; P<0.001). Findings highlight the psycho-physical stress imposed by the combination of intense dynamic exercise with repeated and prolonged apnea intervals during SS events.

Influence of sludge retention time and temperature on the sludge removal in a submerged membrane bioreactor: comparative study between pure oxygen and air to supply aerobic conditions.

Performance of a bench-scale wastewater treatment plant, which consisted of a membrane bioreactor, was monitored daily using pure oxygen and air to supply aerobic conditions with the aim of studying the increases of the aeration and sludge removal efficiencies and the effect of the temperature. The results showed the capacity of membrane bioreactor systems for removing organic matter. The alpha-factors of the aeration were determined for six different MLSS concentrations in order to understand the system working when pure oxygen and air were used to supply aerobic conditions in the system. Aeration efficiency was increased between 30.7 and 45.9% when pure oxygen was used in the operation conditions (a hydraulic retention time of 12 h and MLSS concentrations between 4,018 and 11,192 mg/L). Sludge removal efficiency increased incrementally, from 0.2 to 1.5% when pure oxygen was used at low sludge retention time and from 1.5% to 15.4% at medium sludge retention time when temperature conditions were lower than 20°C. Moreover, the difference between calculated and experimental sludge retention time was lesser when pure oxygen was used to provide aerobic conditions, so the influence of the temperature decreased when the pure oxygen was used. These results showed the convenience of using pure oxygen due to the improvement in the performance of the system.

[Anteromedialization in the treatment of high-riding and lateralized patella in adults]. / Anteromedialización en el tratamiento de la rótula alta y lateralizada en el adulto.

INTRODUCTION: A study conducted at our hospital showed that patellofemoral instability associated with a high-riding and lateralized patella occurred in 34 out of 4,954 admitted patients (6.86% rate). In order to treat these alterations we studied a series of patients in whom an anteromedialization technique was used. MATERIAL AND METHODS: This is a prospective, cross-sectional, descriptive cohort study, with probabilistic sampling, conducted between March 1st, 2009 and September 1st, 2011. Twenty patients who met the inclusion criteria were selected. The same technique was used in all patients, performed by the same surgeon, with the same postoperative and rehabilitation protocol. The modified Lyshom scale was applied and the results were assessed by two blinded observers whose concordance was assessed with the Kappa index. RESULTS: Twenty patients were treated, 12 females and 8 males; mean age was 20 years. In 14 patients the dislocating event occurred in one of the knees and in 6 patients it was bilateral; the right side predominated. Dislocation was recurrent in 7 patients and relapsing in 13; 12 of the latter had undergone soft tissue realignment and lateral retinaculum release, and one patellar advancement. The mean clinical Q angle was 18 degrees preoperatively and 7 degrees postoperatively. The preoperative and postoperative radio- graphic assessment was equivalent to a Kappa of 88%. Mean healing time of the osteotomy was 8 weeks; 2 hemarthroses occurred in the immediate postoperative period, which were resolved with puncture; no fractures and no graft collapses were reported. The mean Lysholm scale was 90.9 at 6 months (interobserver kappa of 90%). All patients had quadriceps atrophy of 1-2 cm, one patient had residual pain and by the end of the study none of the patients had had relapsing dislocation. CONCLUSIONS: This technique corrects the dislocation resulting from a high-riding and lateralized patella by modifying the Q angle. It involves minimal complications, uses a small 5 cm approach and does not require special guides. This study remains open to long-term follow-up to detect the presence or absence of patellofemoral arthrosis.

Usefulness and metabolic implications of a 60-second repeated jumps test as a predictor of acrobatic jumping performance in gymnasts.

Gymnastics floor exercises are composed of a set of four to five successive acrobatic jumps usually called a "series". The aims of the study were: 1) to relate the acrobatic gymnastics performance of these series with a repeated jumps test of similar duration (R60), 2) to study the relation between R60 and physiological parameters (heart rate and blood lactate), and the performance obtained in different kinds of jumps, 3) to confirm whether R60, executed without a damped jumping technique, can be considered an anaerobic lactic power test. Twenty male and twenty-four female gymnasts performed three repeated jumps tests for 5 s (R5), 10 s (R10) and 60 s (R60) and vertical jumps, such as drop jumps (DJ), squat jumps (SJ) and countermovement jumps (CMJ). We assessed heart rate (HR) and blood lactate during R10 and R60. The average values of the maximal blood lactate concentration (Lmax) after R10 (males = 2.5±0.6 mmol · l(-1); females = 2.1±0.8 mmol · l(-1)) confirm that anaerobic glycolysis is not activated to a high level. In R60, the Lmax (males = 7.5±1.7 mmol · l(-1) females = 5.9±2.1 mmol · l(-1)) that was recorded does not validate R60 as an anaerobic lactic power test. We confirmed the relation between the average power obtained in R60 (R60Wm) and the acrobatic performance on the floor. The inclusion in the multiple regression equation of the best power in DJ and the best flight-contact ratio (FC) in R5 confirms the influence of other non-metabolic components on the variability in R60 performance, at least in gymnasts.

Isometric knee extensor fatigue following a Wingate test: peripheral and central mechanisms.

Central and peripheral fatigue have been explored during and after running or cycling exercises. However, the fatigue mechanisms associated with a short maximal cycling exercise (30 s Wingate test) have not been investigated. In this study, 10 volunteer subjects performed several isometric voluntary contractions using the leg muscle extensors before and after two bouts of cycling at 25% of maximal power output and two bouts of Wingate tests. Transcranial magnetic stimulation (TMS) and electrical motor nerve stimulation (NM) were applied at rest and during the voluntary contractions. Maximal voluntary contraction (MVC), voluntary activation (VA), twitch amplitude evoked by electrical nerve stimulation, M wave and motor potential evoked by TMS (MEP) were recorded. MVC, VA and twitch amplitude evoked at rest by NM decreased significantly after the first and second Wingate tests, indicating central and peripheral fatigue. MVC and VA, but not the twitch amplitude evoked by NM, recovered before the second Wingate test. These results suggest that the Wingate test results in a decrease in MVC associated with peripheral and central fatigue. While the peripheral fatigue is associated with an intramuscular impairment, the central fatigue seems to be the main reason for the Wingate test-induced impairment of MVC.

VO2 kinetics in 200-m race-pace front crawl swimming.

Studies that aim to characterize oxygen uptake kinetics in efforts above maximal oxygen consumption intensity are scarce. Our aim was to analyze the oxygen kinetics in a maximal 200-m front crawl, all measurements being conducted in swimming pool conditions. 10 high-level male swimmers performed a maximal 200-m bout and oxygen uptake was directly measured through breath-by-breath gas analysis. Mean (±SD) peak oxygen uptake was 68.58 (±5.79) ml.kg(-1).min(-1), evidencing a fast component phase. As expected, peak oxygen uptake presented a direct relationship with mean swimming speed of the first 50-m lap and with the 200-m effort, and was also correlated with the amplitude of the fast component (r=0.75, r=0.72, r=0.73, p<0.05, respectively). The observed mean amplitude value was higher than those observed in the literature for other exercise intensity domains. However, the time for its onset, as well as the duration for attaining the steady state, was shorter, as the peak oxygen uptake was not correlated with these 2 components. Moreover, as previously described for swimming at high intensities, the slow component phenomenon was not observed. Aerobic metabolic pathway accounted for 78.6%, confirming the high aerobic contribution in middle distance swimming events.

New indices for quantification of the power spectrum of heart rate variability time series without the need of any frequency band definition.

This paper presents a new family of indices for the frequency domain analysis of heart rate variability time series that do not need any frequency band definition. After proper detrending of the time series, a cumulated power spectrum is obtained and frequencies that contain a certain percentage of the power below them are identified, so median frequency, bandwidth and a measure of the power spectrum asymmetry are proposed to complement or improve the classical spectral indices as the ratio of the powers of LF and HF bands (LF/HF). In normal conditions the median frequency provides similar information as the classical indices, while the bandwidth and asymmetry can be complementary measures of the physiological state of the tested subject. The proposed indices seem to be a good choice for tracking changes in the power spectrum in exercise stress, and they can guide in the determination of frequency band limits in other animal species.

Performance of bench-scale membrane bioreactor under real work conditions using pure oxygen: viscosity and oxygen transfer analysis.

Pure oxygen to supply the aerobic condition was used in the performance of a bench-scale submerged membrane bioreactor (MBR). The pilot plant was located in the wastewater treatment plant of the city of Granada (Spain) and the experimental work was divided into two stages (Unsteady state and steady state conditions). Operation parameters (MLSS, MLVSS and dissolved oxygen concentration) and physical characteristics (temperature, conductivity, pH, COD and BOD(5)) were daily monitored. The results showed the capacity of the MBR systems to remove organic material under a hydraulic retention time of 18.46 h and sludge retention time of 18.6 days. Therefore, Viscosity of the sludge and alphakLa-factor of the aeration, were determinate in the steady stage condition to understand the behavior of the system when pure oxygen has been used to supply the aerobic conditions of the MBR system showed an alpha-factor of 0.238 when the viscosity of the system was 4.04 Cp.

Validity of a swimming snorkel for metabolic testing.

Two models of a swimming snorkel connected to a portable metabolic cart (Cosmed K4 b2, Rome, Italy) were assessed using a gas exchange simulation system. Four standardized testing protocols were designed to mimic different swimming conditions and were performed similarly in three conditions so that both snorkels could be compared to measured values obtained by connecting the simulator directly with the gas analyzer. Simulated and measured values were highly correlated (R2 = 0.891 to 0.998) and in good agreement, with only a small overestimation of expiratory tidal volume (4 %, p = 0.005), not large enough to significantly affect the accuracy of ventilation or gas exchange parameters. Values measured using both swimming snorkels also highly correlated with simulated values, particularly for the ventilatory and primary gas exchange variables (R2 = 0.996 and 0.998 in both models for VO2 and VCO2, respectively). A moderate overestimation of FEO2 was observed in both models (2.65 % and 2.48 % relative, p = 0.03) and attributed to minimal mixing of inspiratory and expiratory gases, although not affecting VO2 measurements. We conclude that both snorkels are valid devices for measuring pulmonary breath-by-breath gas exchange parameters in connection with the K4 b2 across a wide physiological range.