Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training

We investigated functional, morphological and molecular adaptations to strength training exercise and cold water immersion (CWI) through two separate studies. In one study, 21 physically active men strength trained for 12 weeks (2 d⋅wk–1), with either 10 min of CWI or active recovery (ACT) after each training session. Strength and muscle mass increased more in the ACT group than in the CWI group (P<0.05). Isokinetic work (19%), type II muscle fibre cross-sectional area (17%) and the number of myonuclei per fibre (26%) increased in the ACT group (all P<0.05) but not the CWI group. In another study, nine active men performed a bout of single-leg strength exercises on separate days, followed by CWI or ACT. Muscle biopsies were collected before and 2, 24 and 48 h after exercise. The number of satellite cells expressing neural cell adhesion molecule (NCAM) (10−30%) and paired box protein (Pax7)(20−50%) increased 24–48 h after exercise with ACT. The number of NCAM+ satellitecells increased 48 h after exercise with CWI. NCAM+- and Pax7+-positivesatellite cell numbers were greater after ACT than after CWI (P<0.05). Phosphorylation of p70S6 kinaseThr421/Ser424 increased after exercise in both conditions but was greater after ACT (P<0.05). These data suggest that CWI attenuates the acute changes in satellite cell numbers and activity of kinases that regulate muscle hypertrophy, which may translate to smaller long-term training gains in muscle strength and hypertrophy. The use of CWI as a regular post-exercise recovery strategy should be reconsidered.

Effects of cold water immersion and active recovery on hemodynamics and recovery of muscle strength following resistance exercise

Cold water immersion (CWI) and active recovery (ACT) are frequently used as post-exercise recovery strategies. However, the physiological effects of CWI and ACT after resistance exercise are not well characterized. We examined the effects of CWI and ACT on cardiac output (Q), muscle oxygenation (SmO2) and blood volume (tHb), muscle temperature (Tmuscle ) and isometric strength after resistance exercise. On separate days, 10 men performed resistance exercise, followed by 10 min CWI at 10°C or 10 min ACT (low-intensity cycling). Q (7.9±2.7 l) and Tmuscle (2.2±0.8ºC) increased, whereas SmO2 (-21.5±8.8%) and tHb (-10.1±7.7 μM) decreased after exercise (p<0.05). During CWI, Q ̇(-1.1±0.7 l) and Tmuscle (-6.6±5.3ºC) decreased, while tHb (121±77 μM) increased (p<0.05). In the hour after CWI, Q ̇and Tmuscle remained low, while tHb also decreased (p<0.05). By contrast, during ACT, Q ̇(3.9±2.3 l), Tmuscle (2.2±0.5ºC), SmO2 (17.1±5.7%) and tHb (91±66 μM) all increased (p<0.05). In the hour after ACT, Tmuscle and tHb remained high (p<0.05). Peak isometric strength during 10 s maximum voluntary contractions (MVCs) did not change significantly after CWI, whereas it decreased after ACT (-30 to -45 Nm; p<0.05). Muscle deoxygenation time during MVCs increased after ACT (p<0.05), but not after CWI. Muscle reoxygenation time after MVCs tended to increase after CWI (p=0.052). These findings suggest firstly that hemodynamics and muscle temperature after resistance exercise are dependent on ambient temperature and metabolic demands with skeletal muscle, and secondly, that recovery of strength after resistance exercise is independent of changes in hemodynamics and muscle temperature.

Computer analysis of impact behavior of concrete filled steel tube columns

This paper presents a numerical study of the response of axially loaded concrete filled steel tube (CFST) columns under lateral impact loading using explicit non-linear finite element techniques. The aims of this paper are to evaluate the vulnerability of existing columns to credible impact events as well as to contribute new information towards the safe design of such vulnerable columns. The model incorporates concrete confinement, strain rate effects of steel and concrete, contact between the steel tube and concrete and dynamic relaxation for pre-loading, which is a relatively recent method for applying a pre-loading in the explicit solver. The finite element model was first verified by comparing results with existing experimental results and then employed to conduct a parametric sensitivity analysis. The effects of various structural and load parameters on the impact response of the CFST column were evaluated to identify the key controlling factors. Overall, the major parameters which influence the impact response of the column are the steel tube thickness to diameter ratio, the slenderness ratio and the impact velocity. The findings of this study will enhance the current state of knowledge in this area and can serve as a benchmark reference for future analysis and design of CFST columns under lateral impact.

Effect of hydrodynamics and surface roughness on the electrochemical behaviour of carbon steel in CSG produced water

The influence of fluid flow, surface roughness and immersion time on the electrochemical behaviour of carbon steel in coal seam gas produced water under static and hydrodynamic conditions has been studied. The disc electrode surface morphology before and after the corrosion test was characterized using scanning electron microscopy (SEM). The corrosion product was examined using X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD).The results show that the anodic current density increased with increasing surface roughness and consequently a decrease in corrosion surface resistance. Under dynamic flow conditions, the corrosion rate increased with increasing rotating speed due to the high mass transfer coefficient and formation of non-protective akaganeite β- FeO(OH) and goethite α- FeO(OH) corrosion scale at the electrode surface.The corrosion rate was lowest at 0 rpm.The corrosion rate decreased in both static and dynamic conditions with increasing immersion time. The decrease in corrosion rate is attributed to the deposition of corrosion products on the electrode surface. SEM results revealed that the rougher surface exhibited a great tendency toward pitting corrosion.

Simultaneous voltammetric determination of four triazine herbicides in water samples with the aid of chemometrics

A novel differential pulse voltammetry (DPV) method was developed for the simultaneous analysis of herbicides in water. A mixture of four herbicides, atrazine, simazine, propazine and terbuthylazine was analyzed simultaneously and the complex, overlapping DPV voltammograms were resolved by several chemometrics methods such as partial least squares (PLS), principal component regression (PCR) and principal component–artificial networks (PC–ANN). The complex profiles of the voltammograms collected from a synthetic set of samples were best resolved with the use of the PC–ANN method, and the best predictions of the concentrations of the analytes were obtained with the PC-ANN model (%RPET = 6.1 and average %Recovery = 99.0). The new method was also used for analysis of real samples, and the obtained results were compared well with those from the GC-MS technique. Such conclusions suggest that the novel method is a viable alternative to the other commonly used methods such as GC, HPLC and GC-MS.

Robust principal component analysis in water quality index development

Some statistical procedures already available in literature are employed in developing the water quality index, WQI. The nature of complexity and interdependency that occur in physical and chemical processes of water could be easier explained if statistical approaches were applied to water quality indexing. The most popular statistical method used in developing WQI is the principal component analysis (PCA). In literature, the WQI development based on the classical PCA mostly used water quality data that have been transformed and normalized. Outliers may be considered in or eliminated from the analysis. However, the classical mean and sample covariance matrix used in classical PCA methodology is not reliable if the outliers exist in the data. Since the presence of outliers may affect the computation of the principal component, robust principal component analysis, RPCA should be used. Focusing in Langat River, the RPCA-WQI was introduced for the first time in this study to re-calculate the DOE-WQI. Results show that the RPCA-WQI is capable to capture similar distribution in the existing DOE-WQI.

Analysis of effects of axial shortening of steel columns in frame structure

Steel columns in frame structure always carry heavy upcoming compressive forces. As a consequence, axial shortening becomes a common phenomenon in a multistoried steel structure. A 100 storied steel structure is analyzed in SAP2000 to study the magnitude overall effects of column shortening. It was found from the study that the maximum axial shortening occurs at the columns of top storey of the steel structure and at the columns of bottom storey, the axial deformation is negligible. The increasing rate of axial shortening is significant at the initial levels. However, at the upper levels, the amount of axial shortening in steel columns differs insignificantly. In the selected rigid frame structure, the axial shortening of adjacent steel columns is found to influence significantly the differential shortening of the structure. The consequent effect of differential shortening leads to develop excessive stress in the corner joints which ultimately hamper the normal behavior of the structural systems. The results are discussed elaborately in the paper.

Separate or simultaneous removal of radioactive cations and anions from water by layered sodium vanadate-based sorbents

Nanofibers of sodium vanadate, consisting of very thin negatively charged layers and exchangeable sodium ions between the layers, are efficient sorbents for the removal of radioactive 137Cs+ and 85Sr2+ cations from water. The exchange of 137Cs+ or 85Sr2+ ions with the interlayer Na+ ions eventually triggered structural deformation of the thin layers, trapping the 137Cs+ and 85Sr2+ ions in the nanofibers. Furthermore, when the nanofibers were dispersed in a AgNO3 solution at pH >7, well-dispersed Ag2O nanocrystals formed by firmly anchoring themselves on the fiber surfaces along planes of crystallographic similarity with those of Ag2O. These nanocrystals can efficiently capture I– anions by forming a AgI precipitate, which was firmly attached to the substrates. We also designed sorbents that can remove 137Cs+ and 125I– ions simultaneously for safe disposal by optimizing the Ag2O loading and sodium content of the vanadate. This study confirms that sorbent features such as fibril morphology, negatively charged thin layers and readily exchangeable Na+ ions between the layers, and the crystal planes for the formation of a coherent interface with Ag2O nanocrystals on the fiber surface are very important for the simultaneous uptake of cations and anions.

Predictive models for water sources with high susceptibility for bromine-containing disinfection by-product formation: Implications for water treatment

This study examines a matrix of synthetic water samples designed to include conditions that favour brominated disinfection by-product (Br-DBP) formation, in order to provide predictive models suitable for high Br-DBP forming waters such as salinity-impacted waters. Br-DBPs are known to be more toxic than their chlorinated analogues, in general, and their formation may be favoured by routine water treatment practices such as coagulation/flocculation under specific conditions; therefore, circumstances surrounding their formation must be understood. The chosen factors were bromide concentration, mineral alkalinity, bromide to dissolved organic carbon (Br/DOC) ratio and Suwannee River natural organic matter concentration. The relationships between these parameters and DBP formation were evaluated by response surface modelling of data generated using a face-centred central composite experimental design. Predictive models for ten brominated and/or chlorinated DBPs are presented, as well as models for total trihalomethanes (tTHMs) and total dihaloacetonitriles (tDHANs), and bromide substitution factors for the THMs and DHANs classes. The relationships described revealed that increasing alkalinity and increasing Br/DOC ratio were associated with increasing bromination of THMs and DHANs, suggesting that DOC lowering treatment methods that do not also remove bromide such as enhanced coagulation may create optimal conditions for Br-DBP formation in waters in which bromide is present.

The exhaustive reduction of formylporphyrins to methylporphyrins using dimethylformamide/water as reductant under microwave irradiation

The reduction of meso-formyl derivatives of 5,15-diaryl- and 5,10,15-triphenylporphyrin (and their nickel(II) complexes) to the corresponding meso-methyl porphyrins is achieved in high yield by microwave heating of the substrate in dimethylformamide (DMF) in the presence of acids such as trifluoroacetic acid, or even just with added water. The reactions are complete in less than 30 min at 250 °C. The reaction is strongly suppressed in very dry DMF in the absence of added acid. The meso-hydroxymethyl porphyrins are also reduced to the methyl derivatives, suggesting the primary alcohols may be intermediates in the exhaustive reduction. UV-visible spectra taken at intervals during reaction at 240 °C indicated that at least one other intermediate is present, but it was not identified. In d7-DMF, the methylporphyrin isolated was mainly Por-CD2H, showing that both of the added hydrogens arise from the solvent, and not from the added water or acid.

Graphene quantum dots and the resonance light scattering technique for trace analysis of phenol in different water samples

A novel, highly selective resonance light scattering (RLS) method was researched and developed for the analysis of phenol in different types of industrial water. An important aspect of the method involved the use of graphene quantum dots (GQDs), which were initially obtained from the pyrolysis of citric acid dissolved in aqueous solutions. The GQDs in the presence of horseradish peroxidase (HRP) and H2O2 were found to react quantitatively with phenol such that the RLS spectral band (310 nm) was quantitatively enhanced as a consequence of the interaction between the GQDs and the quinone formed in the above reaction. It was demonstrated that the novel analytical method had better selectivity and sensitivity for the determination of phenol in water as compared to other analytical methods found in the literature. Thus, trace amounts of phenol were detected over the linear ranges of 6.00×10−8–2.16×10−6 M and 2.40×10−6–2.88×10−5 M with a detection limit of 2.20×10−8 M. In addition, three different spiked waste water samples and two untreated lake water samples were analysed for phenol. Satisfactory results were obtained with the use of the novel, sensitive and rapid RLS method.

Multifunctional three-dimensional T-junction graphene micro-wells: Energy-efficient, plasma-enabled growth and instant water-based transfer for flexible device applications

The “third-generation” 3D graphene structures, T-junction graphene micro-wells (T-GMWs) are produced on cheap polycrystalline Cu foils in a single-step, low-temperature (270 °C), energy-efficient, and environment-friendly dry plasma-enabled process. T-GMWs comprise vertical graphene (VG) petal-like sheets that seemlessly integrate with each other and the underlying horizontal graphene sheets by forming T-junctions. The microwells have the pico-to-femto-liter storage capacity and precipitate compartmentalized PBS crystals. The T-GMW films are transferred from the Cu substrates, without damage to the both, in de-ionized or tap water, at room temperature, and without commonly used sacrificial materials or hazardous chemicals. The Cu substrates are then re-used to produce similar-quality T-GMWs after a simple plasma conditioning. The isolated T-GMW films are transferred to diverse substrates and devices and show remarkable recovery of their electrical, optical, and hazardous NO2 gas sensing properties upon repeated bending (down to 1 mm radius) and release of flexible trasparent display plastic substrates. The plasma-enabled mechanism of T-GMW isolation in water is proposed and supported by the Cu plasma surface modification analysis. Our GMWs are suitable for various optoelectronic, sesning, energy, and biomedical applications while the growth approach is potentially scalable for future pilot-scale industrial production.

Two-scale computational modelling of water flow in unsaturated soils containing irregular-shaped inclusions

The focus of this paper is two-dimensional computational modelling of water flow in unsaturated soils consisting of weakly conductive disconnected inclusions embedded in a highly conductive connected matrix. When the inclusions are small, a two-scale Richards’ equation-based model has been proposed in the literature taking the form of an equation with effective parameters governing the macroscopic flow coupled with a microscopic equation, defined at each point in the macroscopic domain, governing the flow in the inclusions. This paper is devoted to a number of advances in the numerical implementation of this model. Namely, by treating the micro-scale as a two-dimensional problem, our solution approach based on a control volume finite element method can be applied to irregular inclusion geometries, and, if necessary, modified to account for additional phenomena (e.g. imposing the macroscopic gradient on the micro-scale via a linear approximation of the macroscopic variable along the microscopic boundary). This is achieved with the help of an exponential integrator for advancing the solution in time. This time integration method completely avoids generation of the Jacobian matrix of the system and hence eases the computation when solving the two-scale model in a completely coupled manner. Numerical simulations are presented for a two-dimensional infiltration problem.

Evaluation of electrocoagulation for the pre-treatment of coal seam water

This work explored the applicability of electrocoagulation (EC) using aluminium electrodes for the removal of contaminants which can scale and foul reverse osmosis membranes from a coal seam (CS) water sample, predominantly comprising sodium chloride, and sodium bicarbonate. In general, the removal efficiency of species responsible for scaling and fouling was enhanced by increasing the applied current density/voltage and contact times (30–60 s) in the EC chamber. High removal efficiencies of species potentially responsible for scale formation in reverse osmosis units such as calcium (100%), magnesium (87.9%), strontium (99.3%), barium (100%) and silicates (98.3%) were achieved. Boron was more difficult to eliminate (13.3%) and this was postulated to be due to the elevated solution pH. Similarly, fluoride removal from solution (44%) was also inhibited by the presence of hydroxide ions in the pH range 9–10. Analysis of produced flocs suggested the dominant presence of relatively amorphous boehmite (AlOOH), albeit the formation of Al(OH)3 was not ruled out as the drying process employed may have converted aluminium hydroxide to aluminium oxyhydroxide species. Evidence for adsorption of contaminants on floc surface sites was determined from FTIR studies. The quantity of aluminium released during the electrocoagulation process was higher than the Faradaic amount which suggested that the high salt concentrations in the coal seam water had chemically reacted with the aluminium electrodes.