Biotransformation of water lettuce (Pistia stratiotes) to biohydrogen by Rhodopseudomonas palustris.

AIMS: Aim of the paper was to assess the feasibility of producing hydrogen as a biofuel by photofermentation of fermented water lettuce (Pistia stratiotes L.) waste biomass, after a nitrogen-stripping treatment. METHODS AND RESULTS: A natural (42OL) and an engineered strain (CGA676, with low-ammonium sensitivity) of Rhodopseudomonas palustris were used for producing hydrogen. The stripping procedure was highly effective for ammonium removal, with an acceptable selectivity (91% of ammonium was removed; only 14% of total organic acids were lost). Both strains were able to produce hydrogen only in the nitrogen-stripped substrate. The natural strain R. palustris 42OL showed a higher Biochemical Hydrogen Potential (1224 ml l-1 vs 720 ml l-1 ; 50·0 mol m-3 vs 29·4 mol m-3 ), but at a lower rate (5·6 ml l-1  h-1 vs 7·3 ml l-1  h-1 ; 0·23 mol m-3  h-1 vs 0·29 mol m-3  h-1 ) than strain CGA676. CONCLUSIONS: Water lettuce waste biomass can be used for biofuel production, after hydrolization, fermentation and nitrogen stripping. SIGNIFICANCE AND IMPACT OF THE STUDY: The investigation on novel, low cost and sustainable biomasses as feedstocks for biofuel production is a priority. Aquatic plants do not compete for arable land. Moreover, water lettuce is a floating and invasive weed, thus its biomass must be harvested when detrimental, and can now be biotransformed in clean hydrogen.

Postoperative arterial hypotension: the unnoticed enemy.

Postoperative hypotension is a frequently underestimated health problem associated with high morbidity and mortality and increased use of health care resources. It also poses significant clinical, technological, and human challenges for healthcare. As it is a modifiable and avoidable risk factor, this document aims to increase its visibility, defining its clinical impact and the technological challenges involved in optimizing its management, taking clinical-technological, humanistic, and economic aspects into account.

Research priorities in perioperative fluid therapy and hemodynamic monitoring: A Delphi Consensus Survey from the Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section (SHTF) of the Spanish Society of Anesthesiology and Critical Care (SEDAR).

BACKGROUND: Research in fluid therapy and perioperative hemodynamic monitoring is difficult and expensive. The objectives of this study were to summarize these topics and to prioritize these topics in order of research importance. METHODS: Electronic structured Delphi questionnaire over three rounds among 30 experts in fluid therapy and hemodynamic monitoring identified through the Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section of the Spanish Society of Anesthesiology and Critical Care. RESULTS: 77 topics were identified and ranked in order of prioritization. Topics were categorized into themes of crystalloids, colloids, hemodynamic monitoring and others. 31 topics were ranked as essential research priority. To determine whether intraoperative hemodynamic optimization algorithms based on the invasive or noninvasive Hypotension Prediction Index versus other management strategies could decrease the incidence of postoperative complications. As well as whether the use of renal stress biomarkers together with a goal-directed fluid therapy protocol could reduce hospital stay and the incidence of acute kidney injury in adult patients undergoing non-cardiac surgery, reached the highest consensus. CONCLUSIONS: The Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section of the Spanish Society of Anesthesiology and Critical Care will use these results to carry out the research.

Effects of combined endurance and strength training on muscle strength, power and hypertrophy in 40-67-year-old men.

Both strength and endurance training have several positive effects on aging muscle and physical performance of middle-aged and older adults, but their combination may compromise optimal adaptation. This study examined the possible interference of combined strength and endurance training on neuromuscular performance and skeletal muscle hypertrophy in previously untrained 40-67-year-old men. Maximal strength and muscle activation in the upper and lower extremities, maximal concentric power, aerobic capacity and muscle fiber size and distribution in the vastus lateralis muscle were measured before and after a 21-week training period. Ninety-six men [mean age 56 (SD 7) years] completed high-intensity strength training (S) twice a week, endurance training (E) twice a week, combined training (SE) four times per week or served as controls (C). SE and S led to similar gains in one repetition maximum strength of the lower extremities [22 (9)% and 21 (8)%, P<0.001], whereas E and C showed minor changes. Cross-sectional area of type II muscle fibers only increased in S [26 (22)%, P=0.002], while SE showed an inconsistent, non-significant change [8 (35)%, P=0.73]. Combined training may interfere with muscle hypertrophy in aging men, despite similar gains in maximal strength between the strength and the combined training groups.

Effects of whole-body vibration on blood flow and neuromuscular activity in spinal cord injury.

STUDY DESIGN: Crossover trial. OBJECTIVES: To investigate the effects of whole-body vibration (WBV) on muscular activity and blood flow velocity after different vibration treatments in patients with spinal cord injury (SCI). SETTING: Research Center on Physical Disability (Spain). METHODS: Eight individuals with SCI received six 3-min WBV treatments depending on a combination of frequency (10, 20 or 30 Hz) and protocol (constant, that is, three consecutive minutes of WBV, or fragmented, that is, three sets of 1 min of WBV with 1 min of rest between the sets). Femoral artery blood flow velocity was registered at minutes 1, 2 and 3 of WBV, and at minutes 1 and 2 after the end of the stimulus. Electromyography activity (EMG) of vastus lateralis (VL) and vastus medialis (VM) was registered at baseline and during WBV. RESULTS: Peak blood velocity (PBV) increased after 1, 2 and 3 min of WBV. The 10 Hz frequency did not alter blood flow, whereas the 20 Hz frequency increased PBV after 2 and 3 min of WBV, and the 30 Hz frequency increased PBV after 1, 2 and 3 min of WBV and during the first minute after the end of the stimulus. No protocol effect was observed for blood parameters. EMG activity of VL and VM increased independently of the applied frequency or protocol. CONCLUSION: WBV is an effective method to increase leg blood flow and to activate muscle mass in SCI patients, and could be considered to be incorporated in their rehabilitation programs.

Effects of different vibration exercises on bench press.

This study was undertaken to analyze the effects of different vibration recovery strategies via feet or hands on the number of repetitions performed and on mean velocity, peak velocity and blood lactate concentration during consecutive bench-press sets. 9 elite judo athletes performed 3 sets of bench press at 60% of one-repetition maximum (1RM), leading to failure and allowing a 180 s rest period between sets. During the rest period, 1 of the 3 following procedures was performed: 150 s rest plus 30 s push-up vibration exercise (Push-up), 150 s rest plus 30 s squat vibration exercise (Squat) or 180 s only rest (Passive). Statistical analysis revealed that the Squat condition resulted in a significant increase in the number of repetitions achieved, in comparison with all other rest strategies. However, kinematic parameters and blood lactate concentration were not affected by vibration. These data suggest that a vibration stimulus applied to the feet, between sets, can result in positive improvements in upper body resistance exercise performance. Although the mechanisms are not fully understood, this positive effect of vibration could be due to an increased motor cortex excitability and voluntary drive.

Biological and psychological monitoring of training status during an entire season in top kayakers.

AIM: The aim of this study was to analyze changes in selected biological and psychological variables in a group of top level kayakers along a 42-week training season. METHODS: Eight top junior sprint kayakers (age=16.8±2.1) (5 men and 3 women) with international competitive experience participated in the research. During the 42-wk season the subjects were tested in three occasions: (T1) in the second week of the general training period, (T2) at the beginning of the specific training period, (T3) at the beginning of the competitive training period. Firstly, subjects were asked to complete the Recovery-Stress Questionnaire for Athletes (RESTQ-Sport) and the Profile of Mood States (POMS) questionnaires, and Borg´s rate of perceived exertion scale (RPE). Immediately after, blood samples were collected and white blood cells, creatine kinase (CK), C-reactive protein (CRP), myeloperoxidase protein levels (MPO) and glutathione status were determined. ANOVA with repeated measures was used to determine the differences between tests. RESULTS: From the hematological and biochemical measures only total leukocytes changed significantly, increasing at T3 when compared to T1. There were no differences along the entire season in both RESTQ-Sport and POMS scores or indices. Concerning performance, the group improved their maximal strength (+17.4% in bench-press 1RM) and their specific-distance time (+9.8%). The main finding of the present study was that training was well-balanced between stress and recovery because while specific performance increased, signs of overtraining were not found. CONCLUSION: Training monitoring in athletes should be performed in a multilevel approach using measurements of performance as well as biological or psychological parameters.

Whole-body vibration training increases muscle strength and mass in older women: a randomized-controlled trial.

To determine whether 10 weeks of whole-body vibration (WBV) training has a significant effect on strength, muscle mass, muscle power, and mobility in older women, 26 subjects were randomly assigned to a WBV training group (n=13; mean age 79 years) and a control (CON) group (n=13; mean age 76 years). Maximal voluntary isometric contraction (MVIC) increased 38.8% in the WBV group, without changes in the CON group. Electromyographic activity of the vastus medialis (VM), the vastus lateralis, and the biceps femoris (BF) did not change in either group. Thigh muscle cross-sectional area increased significantly after training in VM (8.7%) and BF (15.5%). Muscle power at 20%, 40%, and 60% MVIC decreased from pre-test to post-test in the CON group; however, WBV training prevented the decrease in the WBV group. Consequently, mobility, measured by the Timed Up and Go test, increased significantly after training (9.0%) only in the WBV group. Ten weeks of lower limb WBV training in older women produces a significant increase in muscle strength induced by thigh muscle hypertrophy, with no change in muscle power. The adaptations to WBV found in the present study may be of use in counteracting the loss of muscle strength and mobility associated with age-induced sarcopenia.

A novel two-phase bioprocess for the production of Arthrospira (Spirulina) maxima LJGR1 at pilot plant scale during different seasons and for phycocyanin induction under controlled conditions.

A two-phase outdoor cultivation bioprocess for Arthrospira maxima LJGR1 combined with phycocyanin induction in concentrated cultures under controlled conditions was evaluated using a modified low-cost Zarrouk medium. Growth was monitored during 4 cycles in 2018 and 4 cycles in 2019. Biomass was harvested and concentrated using membrane technology at the end of each cycle for further phycocyanin induction using blue LED light (controlled conditions, 24 h). The highest biomass productivity was observed during spring and summer cycles (13.63-18.97 gDWm-2 d-1); during mid-fall and mid-end fall, a decrease was observed (9.93-7.76 gDWm-2 d-1). Under favorable growth conditions, phycocyanin induction was successful. However, during cycles with unfavorable growth condition, phycocyanin induction was not observed. Reactive-grade phycocyanin (3.72 ± 0.14) was recovered and purified using microfiltration and ultrafiltration technologies.

Effects of resistance training in multiple sclerosis.

This study examined the effects of an eight-week progressive resistance training on different strength manifestations, muscle mass and functionality in multiple sclerosis patients. Thirteen volunteered patients (average age 43 years; range 35-51) with a confirmed diagnosis by a neurologist and mild to moderate disability participated twice a week in an eight-week progressive resistance training program after an eight-week control period without training. Intensity ranged from 40-70% of their maximal voluntary contraction. Outcome assessments included magnetic resonance image of the right and left thighs, strength manifestations (maximal voluntary contraction, muscular endurance and power), and functionality by the Up and Go test. All outcome assessments remained unaltered during the eight-week control period. After the eight-week strength training period, isometric strength (+16%, p<0.01), muscular endurance (+84%; p<0.001), maximal power (+51%, p<0.001), muscular hypertrophy from slice 6/27 to slice 11/27 of both thighs (p<0.05), and functionality (p<0.001) improved significantly. Moderate resistance training programs can improve muscle function without injuries and can be a promising therapy to delay the functional deterioration in multiple sclerosis patients.

Dynamics of dengue epidemics in urban contexts.

Dengue, similar to other arboviral diseases, exhibits complex spatiotemporal dynamics. Even at town or village level, individual-based spatially explicit models are required to correctly reproduce epidemic curves. This makes modelling at the regional level (province, country or continent) very difficult and cumbersome. We propose here a first step to build a hierarchized model by constructing a simple analytical expression which reproduces the model output from macroscopic parameters describing each 'village'. It also turns out to be a good approximation of real urban epidermic outbreaks. Subsequently, a regional model could be built by coupling these equations on a lattice.

Morphological, rheological and mechanical characterization of polypropylene nanocomposite blends.

In the present work, the effectiveness of styrene/ethylene-butylene/styrene rubbers grafted with maleic anhydride (MA) and a metallocene polyethylene (mPE) as toughening materials in binary and ternary blends with polypropylene and its nanocomposite as continuous phases was evaluated in terms of transmission electron microscopy (TEM), scanning electron microscopy (SEM), oscillatory shear flow and dynamic mechanical thermal analysis (DMA). The flexural modulus and heat distortion temperature values were determined as well. A metallocene polyethylene and a polyamide-6 were used as dispersed phases in these binary and ternary blends produced via melt blending in a corotating twin-screw extruder. Results showed that the compatibilized blends prepared without clay are tougher than those prepared with the nanocomposite of PP as the matrix phase and no significant changes in shear viscosity, melt elasticity, flexural or storage moduli and heat distortion temperature values were observed between them. However, the binary blend with a nanocomposite of PP as matrix and metallocene polyethylene phase exhibited better toughness, lower shear viscosity, flexural modulus, and heat distortion temperature values than that prepared with polyamide-6 as dispersed phase. These results are related to the degree of clay dispersion in the PP and to the type of morphology developed in the different blends.

Early explosive force reduction associated with exercise-induced muscle damage.

This study was aimed to analyze the loss of muscle explosive force in the early phase of eccentric exercise-induced damage, and its possible relationships with muscle soreness and blood creatine kinase (CK) levels. Squat jump (SJ) and countermovement jump (CMJ) heights decreased in response to an eccentric exercise (120 eccentric actions of the knee extensors), with reductions that persisted at least for 24 h. The SJ/CMJ ratio was not significantly modified. Blood CK levels changed significantly over time and CK activity was significantly higher at 6 and at 24 h when compared to values obtained immediately after the eccentric exercise. Muscle soreness perceived at 6 h was slightly higher than that experienced just after finalizing the exercise and reached a clearly upper value at 24 h. A highly significant relationship between SJ and CMJ height loss was observed. CK activity at 24 h was significantly related to the SJ height loss at 6 h and to both the SJ height loss and the CMJ height loss immediately after the exercise. In summary, eccentric exercise induced a reduction in the explosive force generating capacity that affected in a similar way the pure concentric jump (SJ) and the jump eliciting the stretch-shortening cycle (CMJ). Results obtained suggest that CK activity is a better predictor of explosive force reduction than soreness, at least when values close to the peak are used.

Changes in muscle architecture induced by low load blood flow restricted training.

In order to ascertain whether differing structural mechanisms could underlie blood flow restricted training (BFRT) and high intensity training (HIT), this study had two aims: (i) to gain an insight into the acute variations of muscle architecture following a single bout of two different volumes of BFRT, and (ii) to compare these variations with those observed after HIT. Thirty-five young men volunteered for the study and were randomly divided into three groups: BFRT low volume (BFRT LV), BFRT high volume (BFRT HV) and traditional high intensity resistance training (HIT). All subjects performed a bilateral leg extension exercise session with a load of 20% of one repetition maximum (1RM) in the BFRT groups, whereas the load of the HIT group was equivalent to an 85% of their 1RM. Before and immediately after the exercise bout, ultrasound images were taken from the rectus femoris (RF) and the vastus lateralis (VL). All groups increased their RF (p < 0.001) and VL (p < 0.001) muscle thickness, while the increases in pennation angle were larger in HIT as compared to BFRT LV (p = 0.013) and BFRT HV (p = 0.037). These results support the hypothesis that acute muscle cell swelling may be involved in the processes underlying BFRT induced muscle hypertrophy. Furthermore, our data indicate differing structural responses to exercise between BFRT and HIT.

[Positive effects of physical exercise on reducing the relationship between subcutaneous abdominal fat and morbility risk]. / Asociación entre tejido graso abdominal y riesgo de morbilidad: efectos positivos del ejercicio físico en la reducción de esta tendencia.

INTRODUCTION: The consequences related to the accumulation of abdominal fat above healthy levels create a considerable organic damage. Among the physiological consequences we can highlight heart diseases, hypertension, type-2 diabetes, obesity and metabolic syndrome, which drastically reduce life expectancy and quality. Evidence shows that health improvement is correlated to greater levels of physical activity. However, physical exercise can create oxidative damage on organs and muscular tissue, more relevant in subjects with a high percentage of abdominal fat. This piece of work determines which are the fundamental variables of the exercise program in order to optimize its advantages while minimizing oxidative stress. MAIN PURPOSE: To know the key variables in the accumulation of abdominal fat above healthy levels, and the role of exercise in prevention and improvement of such issue. SPECIFIC PURPOSES: 1) to identify the key variables in an exercise program aimed at reducing abdominal fat; 2) to understand the relationship between abdominal fat, health and exercise; 3) to review the latest research related to physical exercise and its effect on abdominal adipose tissue. METHODOLOGY: A search and identification of original and reviewed articles will be carried out in indexed impact journals within the main databases. DISCUSSION: Regular physical exercise, most notably aerobic one, reduces body adipose tissue deposits in general, and abdominal ones in particular, both in obese and overweight subjects.

The role of resting duration in the kinematic pattern of two consecutive bench press sets to failure in elite sprint kayakers.

This study aimed to investigate the role of rest period duration (RP) on the time course of the acceleration portion (AP) and mean velocity of the concentric phase across two bench press sets to failure with a submaximal load (60% of the 1RM) using different RP. Ten elite junior kayakers performed, on four different days, two consecutive bench press sets to failure, allowing randomly 1-, 2-, 3- and 4-min RP between sets. AP reached a maximal value of 66% of the concentric movement time. This maximal AP was observed in repetition number 2 or 3, and then AP declined during the set, with a significant decrease when the number of repetitions was over 80% of the total number of repetitions performed. AP and lifting velocity patterns of the concentric phase were not altered during a second set to failure, regardless of RP. However, when velocity was expressed in absolute terms, 1-min RP was insufficient to maintain the average lifting velocity during the second set, compared to the first one. These results may be of use in selecting number of repetitions and resting duration in order to ensure optimal maintenance of the accelerative portion of concentric movement time with different resting-period durations.

Effects of strength and endurance training on antioxidant enzyme gene expression and activity in middle-aged men.

This study was aimed at investigating the effects of a 21-week period of progressive strength or endurance training on peripheral blood mononuclear cells (PBMC) antioxidant enzyme gene expression and activity in healthy middle-aged untrained men. Strength (n=11) and endurance (n=12) training were performed twice a week, including resistance exercises to activate all the main muscle groups or cycle-ergometer pedaling, respectively. mRNA levels of catalase, glutathione peroxidase (GPx), mitochondrial superoxide dismutase (MnSOD) and cytosolic superoxide dismutase (CuZnSOD) were increased after 21 weeks of strength training, while endurance training induced significant changes only in MnSOD and GPx mRNA levels. CuZnSOD protein content was significantly increased only in strength-trained subjects. The program of strength or endurance exercise training had no significant effects on the activity of any of the antioxidant enzymes. In conclusion, in a middle-aged population, 21 weeks of strength or endurance training was a sufficient stimulus to up-regulate mRNA levels of PBMC antioxidant enzymes, the strength training being a more optimal stimulus. However, the discrepancies between enzyme protein and mRNA levels suggest that the present systematic strength or endurance training period had no beneficial effects on enzymatic antioxidant defense mechanisms in previously untrained middle-aged men.