Oxygen Deficit Research Articles

Energy Drinks May Not Impact Excess Postexercise Oxygen Consumption: Considerations for Pre-exercise Test Recommendations

Background: The present study aimed to determine whether energy drink (ED) formulas containing 140 and 100 mg of caffeine have the potential to alter excess postexercise oxygen consumption (EPOC) responses after an incremental exercise test in males and females. Materials and Methods: Participants were submitted to incremental tests to exhaustion after receiving EDs containing 140 and 100 mg of caffeine and a placebo in a randomized order. Results: EPOC was greater in ED containing 140 mg of caffeine (9.47 ± 0.37 L; p < 0.05), but not in 100 mg (9.20 ± 0.374.4 L; p = 0.31) in relation to placebo (8.84 ± 0.37 L). Conclusion: Ingesting an ED containing 140 mg of caffeine may affect EPOC after an incremental exercise to exhaustion. ED containing 100 mg of caffeine, ingested 2 hours before exercise, may not promote changes in EPOC following an incremental exercise to exhaustion protocol and could be acceptable before exercise testing in caffeine habituated young adults. This study was registered with clinicaltrials.gov under the identifier NCT04455009.

Genesis of Antibiotic Resistance LXXII: Turbulence Modeling (TM) of Simplified Severe Sepsis Protocol‐2 (SSSP‐2), NCT01663701: Mechanism(s) of Fluid Volume Overload/endotoxemia Induced Thrombocytopenia / Thrombotic Cascade Augment vasoplegia to elicit Leucocyte(s)‐Platelet(s)‐Erythrocyte(s) aggregates (LPE) rescind starling forces

Here we present a plausible schema for fluid resuscitation induced fluid volume overload altering net filtration pressure (NFP) and the onset of comatose. NCT01663701 (PMID: 28973227) noted that the median volume of iv fluid administered between presentation at ED (Emergency department) (Zero hours) (PMID: 20035633) and 6 hours in the sepsis cohort was 3.5 L. The mean volume administered during a similar time interval in prior sepsis ERP trials were 5.0 L (PMID: 11794169, Rivers et.al.,); 20mls/kg iv 0.9% saline with 5% HAS, FEAST, ISRCTN69856593- PMID: 21615299, Maitland et.al.,); Refer Table 1, list of randomized control EGDT, (PMID: 28460438); 5.059L, PMID: 11794169; ProCESS, NCT00510835. (PMID: 24635773); 4.479L; EGDT, ARISE NCT00975793; (PMID: 25272316); 4.2216 L; ProMISe ISRCTN36307479, (PMID: 25776532) (Table 4, Crit Care. 2016; 20: 160. (PMID: 27364620; PMID: 27756870). In essence, fluid overload induced volume expansion is implicit of a pattern of decline in blood flow velocity leading to hypoxia plausibly dysoxia ultimately to anoxia and/or oxygen debt augment platelet activation - aggregation forming LPE occluding thoroughfare capillary bed at the arterial end educe NFP < 10 mmHg impairing filtration, in turn, CCP⇨ vascular shunt. Experimental evidence suggests that the thrombocytopenia in sepsis is initiated by acute and/or chronic viral infection, Rx-immunosuppression, antibiotic therapy, vascular infusion of fluids, which in turn cause an increase in platelet activation, DIC, hemophagocytic lymphohistiocytosis, IgG associated platelets (PAIgG), in a pathogen-associated molecular pattern (PAMPs), subsequent sequestration with leucocytes in neutrophils extracellular traps (NETs) dependent of damage-associated molecular patterns (DAMPs) form a patient-specific LPE occluding the blood flow into the capillary bed (PMID: 31315248; PMID: 29053592). Based on the aforesaid, pathogenesis, we suggest that prior to the admission to the ER, bacteremia with parasitic infection may have caused an increased in LPE formation and sequestration on the damaged glycocalyx impeding the blood flow in turn perfusion (hypovolemia). Our interpretation is that the volume overload exacerbates reperfusion injury of hypoperfused tissues leading to a remote organ injury consequent multiple organ failure due to hypoxia-dysoxia-anoxia cascade fostering an anaerobic/microaerophilic G- pathogens to colonize at an increased rate in vivo. Thus, the impairment of vasomotion by endotoxemia-vasoplegia in the thoroughfare capillary bed is outflanking our TM efforts of defining the mechanisms leading to the increased mortality rate in NCT01663701 (PMID:29332515; PMID:32019600). Taken together we suggest that the mechanism for induction of comatose requires a minimal time constraint (max 30min) in the following sequence: endotoxemia ⇨ vasoplegia ≠⇨ hemostasis≠⇨ homeostasis ≠⇨ NFP <10mmHg ⇔ CCP⇔ GCS scale 3⇔Hypnotic Trans⬅ exception of Lazarus phenomenon ➡ Clinical End Point (mortality).

Glucose amendment influences restructuring of compacted soil blocks – Results of a field experiment with varying soil-site conditions

Man-induced soil compaction is a widespread problem for soil fertility and soil usability. Negative consequences may persist for a long time. However, the burrowing activity of soil fauna (pore creation) and growth of plant roots as well as swelling and shrinking can loosen compacted soil over time. This study was focused on the question if an increased energy supply can promote the soil-loosening action of soil biota in compacted soil. We conducted an experiment where compacted soil blocks of two different substrates (different pH) with and without addition of glucose (as energy supply) were exposed to sites with contrasting potentials for restructuring (mown grassland and acidic spruce plantation). Glucose addition stimulated the burrowing activity of soil fauna in compacted soil blocks. Synergism between earthworms and plant root growth had the strongest effect on soil loosening. The site conditions (notably pore-creating biological activity) and the soil acidity of the compacted soil play a key role for the structural recovery. In soil blocks without earthworm activity glucose amendment inhibited rooting by plants, most likely because microbial metabolism led to oxygen deficit in the compacted soil block.

Energy System Contribution during 1500M Running in Untrained and Endurance-Trained Asian Male College Students

OBJECTIVES To compare the aerobic and anaerobic energy system contribution during 1500m running between collegiate untrained (UT) and endurance trained (ET) subjects.METHODS Five Asian UT (age: 23.8 ± 0.4 yrs, body fat %: 15.9 ± 5.7 %, height: 174.0 ± 4.1 cm, weight: 65.5 ± 4.1 kg) and 5 Asian ET male participants (age: 24.4 ± 3.9 yrs, body fat %: 12.9 ± 6.9 %, height: 169.4 ± 5.1 cm, weight: 60.6 ± 8.1 kg) participated in this study. Participants attended 3 sessions to determine their body composition, submaximal and maximal oxygen consumption (VO2max) test, 1500m track running session (RS) and 1500m treadmill RS. The maximally accumulated oxygen deficit (MAOD) method was used to calculate energy system contribution.RESULTS The times for the 1500m track run for the UT and ET were 428.0 ± 48.7 and 331.6 ± 14.0 seconds (p=0.004) respectively. There were no significant differences in VO2 between the 1500m track and treadmill RS indicating the participants ran to their personal best times for both trials. The mean VO2max(mL•kg-1•min-1) were significantly different between UT (45.1 ± 5.0) and ET participants (58.3 ± 2.2) (p=0.002). The mean relative contributions of the aerobic and anaerobic energy system during 1500m running were significantly different for the UT, 65.4 ± 7.0%, 34.6 ± 7.0 and ET, 75.7 ± 1.5%, 24.3 ± 1.5 % (p =0.011).CONCLUSIONS The point of equal contribution of the aerobic and the anaerobic systems occurred after thirty to forty seconds of intensive exhaustive running after which the aerobic contribution continues to increase while the anaerobic contribution decreases with increasing duration. By the end of 60th second of exhaustive running, the ET mean aerobic contribution is 71.5% compared to the UT’s 58.6%. This finding suggests a greater reliance on the aerobic energy system by the ET.

Metabolic Profile of Reciprocal Supersets in Young, Recreationally Active Women and Men.

Realzola, RA, Mang, ZA, Millender, DJ, Beam, JR, Bellovary, BN, Wells, AD, Houck, JM, and Kravitz, L. Metabolic profile of reciprocal supersets in young, recreationally active females and males. J Strength Cond Res 36(10): 2709-2716, 2022-Reciprocal supersets (RSSs) are a time-efficient style of resistance exercise (RE) that consist of performing 2 consecutive exercises with opposing muscle groups while limiting rest times between them. Previous research in men indicates a RSS has an increased physiological response when compared with traditional RE (TRAD). No between-sex comparison of metabolic data for RSSs exists. The purpose of this study was to create a metabolic profile for RSSs in men and women. Eighteen resistance-trained individuals underwent 2 bouts of volume-load equated RE: RSS and TRAD. Reciprocal superset exercises were split into 3 clusters: (a) hexagonal bar deadlift superset with leg press, (b) chest press superset with seated row, and (c) overhead dumbbell press superset with latissimus dorsi pull-downs. The TRAD protocol, doing the same exercises, emulated hypertrophy emphasis training. Oxygen uptake (V̇ o2 ), heart rate (HR), blood lactate ([BLa]), rate of perceived exertion (RPE), and excess post-exercise oxygen consumption (EPOC) were measured. Aerobic and anaerobic energy expenditure were estimated using V̇ o2 and lactate, respectively. The level of significance set for this study was p ≤ 0.05. Regardless of sex, a RSS elicited significantly greater average V̇ o2 , HR, [BLa], RPE, and anaerobic and aerobic energy expenditures, and was completed in a shorter time compared with TRAD ( p ≤ 0.05). When compared with women, men had significantly greater EPOC, average [BLa], and anaerobic and aerobic energy expenditures during RSSs ( p ≤ 0.05). The average [BLa] and aerobic energy expenditure of the men were also significantly greater than the women during TRAD ( p ≤ 0.05). This study suggests that a RSS is a metabolically demanding RE session that may elicit increases in musculoskeletal, cardiorespiratory, and physiological adaptations while decreasing the duration of exercise.

Hypoxia tolerance and metabolic coping strategies in Oreochromis niloticus

The Nile tilapia (Oreochromis niloticus) is widely farmed in tropical and subtropical pond culture. O. niloticus is recognized as a species that is tolerant of hypoxic conditions, a trait that may largely be responsible for the success of this species in aquaculture. Until now, neither coping mechanisms nor a comparison of various indices of hypoxia tolerance to characterize the response to hypoxia, have been described. In the present study, Nile tilapia were subjected to hypoxia of increasing severity and duration to examine effects on metabolic rate (MO2) and post hypoxic oxygen debt. MO2 was measured during periods of severe hypoxia at 2.1 kPa O2 (10% oxygen saturation) lasting between 2 and 24 h at 27 °C. Hypoxia tolerance was assessed by determining the critical oxygen tension (Pcrit) and the pO2 at which loss of equilibrium (LOE) occurred. We show that the tolerance of Nile tilapia to severe hypoxia is largely achieved through a capacity for metabolic depression. Despite prolonged exposure to dissolved oxygen levels below Pcrit, the fish showed little excess post-hypoxic oxygen consumption (EPHOC) upon return to normoxic conditions. LOE did not occur until conditions became near-anoxic. Blood pH was not affected by severe hypoxia (2.1 kPa O2), but a significant acidosis occurred during LOE, accompanied by a significant elevation in lactate and glucose levels. The results from the present study indicate that Nile tilapia do not switch to anaerobic metabolism during hypoxia until pO2 falls below 2.1 kPa.

Two-sided effects of prolonged hypoxia and sulfide exposure on juvenile ark shells (Anadara broughtonii)

Oxygen deficit and sulfide have been restrictive factors in mariculture zones. However, the adaptive mechanism in aquatic lives is still unclear. The commercial ark shells Anadara broughtonii were selected to test the tolerance and adaptive responses to prolonged and intermittent hypoxia with or without exogenous sulfide (mild, moderate, high) by evaluating their behavior, mortality, oxidative level, antioxidant responses, and the MAPK-mediated apoptosis in gills. The results indicated that the clams were tolerant to hypoxia and sulfide exposure but vulnerable during reoxygenation from the challenges. Even so, sulfide had remarkable effect on attenuating the accumulation of reactive oxygen species (ROS) and lipid peroxides caused by reoxygenation from prolonged hypoxia. The increase of glutathione level was probably as an early and primary protective response to prevent the expected reperfusion injury from reoxygenation. The challenges suppressed the oxidative level with a dose-dependent effect of sulfide, with an exception when exposed to mild sulfide. Synchronously, biphasic effects of exogenous sulfide on apoptotic cascade, which was induced by mild sulfide while it was inhibited by higher sulfide, were also detected in gills. The induced or inhibited apoptosis by hypoxia and sulfide kept to a typical ROS-MAPK-CASPASE cascade, desiderating further investigation.

Rice growth in a combined submergence and salinity stresses

The occurrence of submergence in agricultural land is increased by the climate change. The level of tolerance in crops depends on many factors including plant stages, duration of submergence. Level of crop tolerance to submergence is likely to decrease when other adverse factors such as salinity exist. Two experiments have been conducted to study the effect of a combined submergence and salinity on rice growth. First experiment studied the salt tolerance at early seedling stage while submerged. Split plot design was used with oxygen concentrations (with and without aeration) as the main plot and salinity levels (0.2, 50, 100 dan 150 mM NaCl) as the sub plot. Second experiment evaluated the length of submergence (one and two weeks) and salinity levels (0.2 and 50 mM NaCl) at older stages rice plants. The results showed that at early stages of seedlings, almost all growth variables have been decreased by salinity. The oxygen deficit reduced salt tolerance in rice seedlings. At older stages of rice, one-week submergence did not reduce rice growth. However, for two weeks submergence, rice submerged in saline water showed better growth compared to those submerged in non-saline water.

Lake Modeling Reveals Management Opportunities for Improving Water Quality Downstream of Transboundary Tropical Dams

AbstractWater quality in tropical rivers is changing rapidly. The ongoing boom of dam construction for hydropower is one of the drivers for this change. In particular, the stratification in tropical reservoirs induces oxygen deficits in their deep waters and warmer surface water temperatures, which often translate into altered thermal and oxygen regimes of downstream river systems, with cascading consequences for the entire aquatic ecosystem. Operation rules of reservoirs, involving water intakes at different levels, could mitigate the consequences for downstream water quality. However, optimized water management of deep reservoirs relies on predictive models for water quality, but such predictive capability is often lacking for tropical dams. Here we focus on the Zambezi River Basin (southern Africa) to address this gap. Using the one‐dimensional General Lake Model, we reproduced the internal dynamics of the transboundary Lake Kariba, the world’s largest artificial lake by volume, created by damming the Zambezi River at the border between Zambia and Zimbabwe. Through this modeling approach, we assessed and quantified the thermal and oxygen alteration in the Zambezi River downstream of the reservoir. Results suggest that these alterations depend directly on Kariba’s stratification dynamics, its water level and the transboundary policies for water withdrawal from the reservoir. Scenario calculations indicate a large potential for mitigating downstream water quality alterations by implementing a hypothetical selective withdrawal technology. However, we show that a different and cooperative management of the existing infrastructure of Kariba Dam has the potential to mitigate most of the actual water quality alterations.

Interaction Between Oxygen Consumption and Carbon Dioxide Emission in a Subtropical Hypoxic Reservoir, Southeastern China

AbstractIt is well recognized that dam construction aggravates eutrophication and hypoxia in river reservoirs, but the interaction between oxygen dynamics and carbon cycling is often unclear. Here we investigated the external and internal controls on oxygen consumption and effects of hypoxia on carbon dioxide (CO2) emission in a subtropical reservoir in southeast China based on detailed field measurements during 2017 and 2018. Hypoxia lasted 4 months starting in mid‐July and expanded from the bottom to near surface water. Rainstorm hyperpycnal flow and unusual hydraulics (outflow exit 40 m from the bottom) resulted in two thermoclines and enhanced the oxygen deficit in deeper water. Microbial respiration accounted for 67.4%–96.5% of total oxygen consumption in the bottom water. The increased supply of organic matter from storm runoff and to a lesser extent primary production in summer enhanced subsequent oxygen consumption. We observed an imbalance between excess CO2 production and oxygen depletion in summer and winter which was likely associated with other processes in the hypolimnion (e.g., chemoautotrophy, anaerobic degradation of organic matter, proton buffering, and nitrification). The water‐air CO2 fluxes suggest that the surface reservoir usually served as a CO2 source, but was a sink in summer due to high primary productivity. CO2 was always oversaturated in the hypolimnion; this layer was at the depth of the dam outflow and ultimately released 68% of annual CO2 efflux to the atmosphere. This research confirmed that construction of a hydropower dam has substantially altered reservoir metabolism and regulated the CO2 emission pathway.

Estimating excess post-exercise oxygen consumption using multiple linear regression in healthy Korean adults: a pilot study.

[Purpose]This pilot study aimed to develop a regression model to estimate the excess post-exercise oxygen consumption (EPOC) of Korean adults using various easy-to-measure dependent variables.[Methods]The EPOC and dependent variables for its estimation (e.g., sex, age, height, weight, body mass index, fat-free mass [FFM], fat mass, % body fat, and heart rate_sum [HR_sum]) were measured in 75 healthy adults ( 31 males, 44 females). Statistical analysis was performed to develop an EPOC estimation regression model using the stepwise regression method.[Results]We confirmed that FFM and HR_sum were important variables in the EPOC regression models of various exercise types. The explanatory power and standard errors of estimates (SEE) for EPOC of each exercise type were as follows: the continuous exercise (CEx) regression model was 86.3% (R2) and 85.9% (adjusted R2), and the mean SEE was 11.73 kcal, interval exercise (IEx) regression model was 83.1% (R2) and 82.6% (adjusted R2), while the mean SEE was 13.68 kcal, and the accumulation of short-duration exercise (AEx) regression models was 91.3% (R2) and 91.0% (adjusted R2), while the mean SEE was 27.71 kcal. There was no significant difference between the measured EPOC using a metabolic gas analyzer and the predicted EPOC for each exercise type.[Conclusion]This pilot study developed a regression model to estimate EPOC in healthy Korean adults. The regression model was as follows: CEx = -37.128 + 1.003 × (FFM) + 0.016 × (HR_sum), IEx = -49.265 + 1.442 × (FFM) + 0.013 × (HR_sum), and AEx = -100.942 + 2.209 × (FFM) + 0.020 × (HR_sum).

A review on biochar as a potential soil fertility enhancer to agriculture

Biochar is a carbon rich material produced from the pyrolysis of biomass at high temperature under oxygen deficit condition. It is recently introduced as one of the effective soil amendments with wide range of environmental benefits. This paper summarizes and discusses the effects of biochar on different soil parameters and crop productivity by reviewing scientific studies conducted around the globe. The benefit is derived especially from the improved soil physical and chemical properties through improvement in soil moisture content, soil bulk density, nitrogen uptake and availability and retention of other soil nutrients, but its effect is highly dependent on feedstocks used, pyrolysis temperature and soil types. It has been found to be more effective on infertile and degraded land. Further research is required to completely reveal the capacity of biochar in enhancing the soil characteristics.

Sex-related differences in accumulated O2 deficit incurred by high-intensity rowing exercise during childhood and adolescence.

The aims of the present study were to determine during childhood and adolescence (i) the effect of sex on non-oxidative energy production, quantified by the accumulated oxygen deficit (AOD), and (ii) the influence of AOD on high-intensity performance. Thirty-nine boys and 35 girls aged 10-17years performed a 60s all-out test on a rowing ergometer to determine AOD and mean power output (MPO). Multiplicative allometric modelling was used to assess the concurrent effects of lean body mass (LBM) and age on AOD. AOD significantly increased with age in both sexes (p < 0.001) with boys exhibiting significantly higher AOD than girls from the age of 14years (10-11.9yr: 1.9 vs 1.9L, 12-13.9yr: 2.4 vs 2.7L, 14-15.9yr: 2.8 vs 4.6L and 16-17.9yr: 2.9 vs 5.2L, in girls and boys respectively, p < 0.001). However, a sex difference was no longer significant when AOD was analysed using an allometric model including age and LBM (p = 0.885). Finally, significant correlations were found between AOD and MPO in boys and girls but with lower evidence in girls (r2 = 0.41 vs. 0.89). Non-oxidative energy production increased more extensively in boys than girls from the age of 14years. Age and LBM accounted for the sexual differentiation of AOD during childhood and adolescence. In addition, AOD was found to be a determinant factor of high-intensity performance, more particularly in boys.

Assessing the Nutrient Dynamics in a Himalayan Warm Monomictic Lake

Thermal stratification is considered to be the most important limnological feature of deep lake ecosystems affecting a water column’s chemical characteristics thereby directly connected with lake management. The lake is also attracting the attention of management authorities, being a growing tourist destination with sustainable environmental management plan. Lake Manasbal is only true warm monomictic urban lake in Kashmir and remains thermally stratified for 8–9 months, with separate layers of epilimnion, metalimnion and hypolimnion.We noticed that in the lower part of the hypolimnion, the process of stratification is characterized by an oxygen deficit (O2 < 1 mg/L). The rate of oxygen depletion reported in the lake’s bottom layers is indicative of the water body’s more eutrophic nature. A clinograde type of pH curve with a wide range of fluctuation from top to bottom layers of water was observed. Thermal stratification of the lake allows ammonium and phosphates to pool in the hypolimnion for much of the stratification period, resulting in concentrations higher than in the epilimnion. Consequently, the lake was characterized by a nutrient-enriched hypolimnion and an epilimnion deprived of nutrients. With the advent of the lake stratification, the thermocline was formed on 15th March between 2 and 3 m and on 7th April between 4 and 6 m, which gradually moved down to 10 m on 4th July and remained at that depth until circulation. The concentration of phosphorus and nitrogen in Lake Manasbal showed an increase towards the bottom, thus revealing an inverse clinograde depth distribution. Due to stratification phenomena in this lake, the internal release and subsequent distribution of nutrients throughout water column especially phosphorus from sediment water interface after mixing is a cause of concern for management authorities as it has the potential to diminish the ecological and aesthetics of the lake.Therefore, we argue that this study will provide some valuable insights on how stratification is affecting the nutrient dynamics and will offer inputs for better management accordingly both from ecological and economic perspectives.

Rapid component of excess post-exercise oxygen consumption of children of different weight status after playing active video games

BackgroundExcess post-exercise oxygen consumption (EPOC) of children could indicate the potential of an exercise therapy to treat or prevent obesity. However, EPOC as a result of playing active video games (AVG) has been poorly investigated. Therefore, we aimed to investigate the rapid component of EPOC of children with healthy weight and overweight/obesity (according to their BMI percentile) after playing AVGs that feature predominately upper body (UB) and whole-body (WB) movement.MethodsTwenty-one children with healthy weight (BMI percentile < 85%) and with overweight/obesity (BMI percentile ≥ 85%) randomly underwent two 10-min AVG sessions (UB and WB). The heart rate (HR), minute ventilation (VE), oxygen consumption (VO2) and carbon dioxide production (VCO2) were recorded during exercise and post-exercise recovery period. For the rapid component of EPOC in each AVG session, measurements were recorded every 15 s for 5-min of post-exercise recovery. The rate of perceived exertion (RPE) was also measured immediately before and after each AVG play.ResultsChildren with overweight/obesity had a higher average of absolute VE, VO2, and VCO2 than their healthy-weight counterparts (BMI percentile < 85%; n = 21) during post-exercise recovery. RPE, HR, and HR% were not different between the game sessions and weight groups. Children with overweight/obesity showed a higher absolute VO2 during EPOC than healthy-weight children in both game sessions, but relative VO2 was higher in healthy-weight children during EPOC. No differences were observed for EPOC between UB and WB sessions.ConclusionsChildren with overweight/obesity had a greater EPOC than healthy-weight children after AVG sessions in terms of absolute oxygen values, whereas healthy-weight children have higher EPOC considering relative VO2 when controlling for body mass. UB and WB AVGs induced a similar EPOC among children with healthy weight and overweight/obesity. As UB and WB AVGs induce the rapid component of EPOC in children regardless their weight status, AVGs could be used as an exercise method to treat and prevent child obesity.

Numerical Investigation of Dissolved Oxygen Transportation through a Coupled SWE and Streeter–Phelps Model

Dissolved oxygen (DO) reflects the self-purification ability of a water body and is also an important indicator for quantifying the water quality. The morphological changes in the cross sections of river channels will affect the hydraulic conditions, and the distribution of pollutants and DO may also be affected, possibly resulting in local oxygen deficits and pollution. To effectively predict the water quality, a coupled model is introduced in this study. The shallow water equation (SWE) is adopted to calculate the hydrodynamic processes, and the modified Streeter–Phelps model is further coupled with the SWE model to evaluate the reaeration. By applying this model, mass transportation and reaeration in rivers are analyzed. The influences of the sudden cross-sectional changes in the river channel on the DO distribution and the reaeration ability are identified. The results reveal that a certain degree of expansion in the river is conducive to reaeration and can also accelerate the consumption of pollutants through the water body’s self-purification. DO transport in two real terrains, including a mountain basin and plain river, is extensively investigated, and the results indicate that the morphological characteristics in the mountain basin will cause the concentration distribution to form inside dead zones, while in the plain, the distribution will form a fan-shaped downstream zone.

Permanganometric determination of oxygen nonstoichiometry in manganites

Strontium and lanthanum manganites are nowadays the subject of extensive research because of their promising electrical and magnetic properties. Strontium manganite, SrMnO3, was successfully prepared by citrate-nitrate autocombustion (CNA) and by the coprecipitation method. These methods were then applied to synthesis of strontium doped lanthanum manganites, La1-xSrxMnO3 (x ​= ​0, 0.1, 0.2 and 0.3). The optimal phase formation conditions were determined by thermogravimetry and differential scanning calorimetry. Crystallization of precursors and calcined powders was studied by X-ray diffraction. Powders, in which pure manganite phase was obtained, were also analyzed by permanganate titration with Mohr’s salt in order to determine oxygen nonstoichiometry. Oxygen stoichiometry was achieved in SrMnO3 powders obtained by the CNA method and calcined at 1000 ​°C as well as in powders obtained by the coprecipitation method and calcined at 1200 ​°C. La1-xSrxMnO3 phase was oxygen stoichiometric for x ​= ​0.3 while decreasing of x resulted in cation deficiency, i.e. oxygen excess. Oxygen deficit was achieved for x ​= ​0.09 upon calcination at 1200 ​°C. The obtained results were confirmed by thermogravimetry and the Rietveld refinement analysis.

Order of concentric and eccentric muscle actions affects metabolic responses.

Resistance exercise provides an effective stimulus for improving the metabolic plasticity of skeletal muscle, and the type of acute muscle contraction plays an important role in determining specific responses and adaptations. The purpose of the current investigation was to examine the effect of contraction order on metabolic responses by comparing monophasic concentric and eccentric squats versus a protocol incorporating alternated concentric and eccentric repetitions. Twelve recreationally active men (21.1±1.1yr) performed three nearly identical squat protocols on separate days. Protocols varied only with contraction-type, including 4 sets × 10 reps concentric-only (CON), eccentric-only (ECC), and BOTH which alternated 5 concentric followed by 5 eccentric reps (CON-ECC; sets 1 and 3) and vice versa (ECC-CON; sets 2 and 4). The experimental trials were performed once weekly in a randomized, counter-balanced order, and expired gases were collected using a two-way non-rebreathing mask and oxygen consumption quantified with indirect calorimetry. Subjects raised (CON) and lowered (ECC) the load in 2s, and all sets (2 min) and repetitions (8 s) were separated by standardized rest intervals. From the BOTH protocol, the increase in metabolic rate was significantly greater (P≤0.05) during squats performed with CON-ECC order (0.60±0.11 L·min-1) compared to ECC-CON (0.44±0.07 L·min-1), but excess postexercise oxygen consumption (EPOC) was opposite, with significantly greater metabolic rate during the 2-minute rest intervals after ECC-CON squats (0.46±0.09 L·min-1) compared to CON-ECC (0.25±0.05 L·min-1). Metabolic rates during and after squats were significantly greater (P≤0.05) with CON (0.63±0.09; 0.49±0.10 L·min-1) compared to ECC (0.34±0.04; 0.20±0.04 L·min-1), respectively. These data present an interesting paradigm regarding the contraction-dependent metabolic responses to monophasic resistance exercise and suggest a greater EPOC following concentric versus eccentric muscle actions.

Trends, insights and effects of the Urban Wastewater Treatment Directive (91/271/EEC) implementation in the light of the Polish coastal zone eutrophication

The intensification of the Baltic Sea eutrophication is associated with the increase of anthropogenic nutrients loads, mainly nitrogen and phosphorus introduced into surface waters from a diffuse, point and natural background sources. Despite the observed decreasing trends in nutrient concentrations in some parts of the Baltic Sea, eutrophication-related indicators continue to deteriorate. This accelerates harmful algal blooms and dissolved oxygen deficits resulting in severe ecosystem disturbance. The paper presents trends, insights and effects of the Urban Wastewater Treatment Directive 91/271/EEC implementation in Poland based on the nutrient riverine loads from Polish territory with particular attention given to the development of municipal wastewater treatment plants under the National Wastewater Treatment Programme 2003–2016. Environmental effects of wastewater infrastructure modernisation are investigated by using available data on the changing nutrient concentrations in the coastal water in 3 basins (Gdansk Basin, Bornholm Basin and Eastern Gotland Basin) belonging to the Polish Exclusive Economic Zone within the Baltic Sea. The results show that the decreasing trend regarding phosphorus loads reduction from municipal effluents was achieved while a stable trend with temporary increases was achieved in terms of nitrogen loads. Moreover, the investigation provides information about the potential bioavailability of discharged effluents before and after the Directive implementation by including total and inorganic forms of nitrogen and phosphorus in the analysis.

Transformation of Battery to High Performance Pseudocapacitor by the Hybridization of W18O49 with RuO2 Nanostructures.

Defects such as oxygen vacancy in the nanostructures have paramount importance in tuning the optical and electronic properties of a metal oxide. Here we report the growth of oxygen deficit tungsten oxide (W18O49) nanorods modified with ruthenium oxide (RuO2) using a simple and economical hydrothermal approach for energy storage application. In this work, a novel approach of hybridizing the W18O49 nanostructure with RuO2 to control the electrochemical performance for energy storage applications has been proposed. The result displays that the hybridization of the nanostructures plays an important role in yielding high specific capacitance of the electrode material. Due to the augmentation of W18O49 and RuO2 nanostructures, the galvanostatic charging and discharging (GCD) mechanism exhibited the transformation from the battery type characteristics of W18O49 into the typical pseudocapacitor feature of hybrid architect nanostructure due to defect creations. The electrochemical measurement of hybrid nanomaterial shows the doubling of specific capacitance to 1126 F/g and 1050 F/g in cyclic voltammetry (CV) and GCD, respectively, in comparison with W18O49 and RuO2 and earlier reports. The enhancement in the stability performance up to 3000 cycles of hybrid is indebted to the stable nature of W18O49 and the high conductivity of RuO2.