Electrokinetic removal of Cu, Zn, Cd, Cr, Pb and Ni from contaminated dredged material has been carried out on thirteen tests evaluating the effectiveness of different enhancing solutions of ...different nature (distilled water, citric acid, acetic acid, humic acid and EDTA). Several experimental variables were analyzed (type of enhancing solution, concentration, zeta potential, initial and final pH of the anolyte and catholyte, constants of chelation equilibriums (logβ) and precipitation (pKs), ionic mobility and charge density passed) and the main mechanisms of their action were critically analyzed. It was derived that there is not just one enhancing solution that is the best universal one for all the metals in the sediment and that modeling of the decontamination process should incorporate the particularities of the different species. However, as a generalization, it could be said that, apart from the charge density passed, the pH of the cathodic solution, quelation ability and the zeta potential seems to appear as the most relevant factors in the efficiency of the process.
The production of hydroxyl radicals (OH) by several photocatalytic cementitious materials was quantified by an adaptation of Terephthalic acid (TA) as probe method for fluorescence spectrometry ...(TA-FL method) for construction materials. Six different materials were evaluated for OH using the method developed, and the photocatalytic activity was compared with the NOx degradation rate, obtaining a positive relationship between both parameters even though the rate of NOx degradation was significantly larger than that of the OH detected. The difference could not be attributed exclusively to the contribution of O2−. Thus, it has been postulated that most of the NOx degradation takes place through the holes, trapped in the surface of the photocatalyst, in equilibrium with OH in the bulk solution, which still makes the quantification of OH as an effective indicator of the photocatalytic performance of cementitious materials.
To provide a neurophysiological tool for assessing sensorimotor pathways, which may differ for those involving distal muscles in simple tasks from those involving distal muscles in a kinetic chain ...task, or proximal muscles in both.
We compared latencies and magnitudes of motor responses in a reaction time paradigm in a proximal (biceps brachii, BB) and a distal (first dorsal interosseous, FDI) muscle following electrical stimuli used as imperative signal (IS) delivered to the index finger. These stimuli were applied during different motor tasks: simple tasks involving either one muscle, e.g. flexing the elbow for BB (FLEX), or pinching a pen for FDI (PINCH); combined tasks engaging both muscles by pinching and flexing simultaneously (PINCH-FLEX). Stimuli were of varying intensity and occasionally elicited a startle response, and a StartReact effect.
In BB, response latencies decreased gradually and response amplitudes increased progressively with increasing IS intensities for non-startling trials, while for trials containing startle responses, latencies were uniformly shortened and response amplitudes similarly augmented across all IS intensities in both FLEX and PINCH-FLEX. In FDI, response latencies decreased gradually and response amplitudes increased progressively with increasing IS intensities in both PINCH and PINCH-FLEX for non-startling trials, but, unlike in BB for the simple task, in PINCH for trials containing startle responses as well. In PINCH-FLEX, FDI latencies were uniformly shortened and amplitudes similarly increased across all stimulus intensities whenever startle signs were present.
Our results suggest the presence of different sensorimotor pathways supporting a dissociation between simple tasks that involve distal upper limb muscles (FDI in PINCH) from simple tasks involving proximal muscles (BB in FLEX), and combined tasks that engage both muscles (FDI and BB in PINCH-FLEX), all in accordance with differential importance in the control of movements by cortical and subcortical structures.
Simple assessment tools may provide useful information regarding the differential involvement of sensorimotor pathways in the control of both simple and combined tasks that engage proximal and distal muscles.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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•Nitroblue tetrazolium ink is reliable to assess the photocatalytic activity.•Emulsions coatings and cement-based materials were evaluated.•Ink progression can be monitored by ...reflectance and colour measurements.•NBT ink proposed test is comparable with oxidative NOx gas removal rate.•NBT ink proposed test is “simple-to-use”, rapid and inexpensive.
The photoactivity of TiO2-bearing construction materials was assessed with nitroblue tetrazolium (NBT) ink. The photocatalytic reaction was monitored with UV–vis diffuse reflectance spectroscopy, colorimetry and digital image processing. The results delivered by the three datasets were linearly related, even though the experimental setup was inexpensive and involved only handheld instruments. The NBT reduction and ISO 22197-1 oxidative NOx removal findings also proved to be acceptably linear, may, then, be promising alternatives to conventional NOx photocatalytic performance testing. The advantages of the procedure proposed over conventional testing include convenience of use, time savings, in-situ applicability, readily distinguishable colour change and low cost.
The purpose of this review was to identify risk factors, prognostic factors, and comorbidities associated with common spinal disorders.
A scoping review of the literature of common spinal disorders ...was performed through September 2016. To identify search terms, we developed 3 terminology groups for case definitions: 1) spinal pain of unknown origin, 2) spinal syndromes, and 3) spinal pathology. We used a comprehensive strategy to search PubMed for meta-analyses and systematic reviews of case-control studies, cohort studies, and randomized controlled trials for risk and prognostic factors and cross-sectional studies describing associations and comorbidities.
Of 3,453 candidate papers, 145 met study criteria and were included in this review. Risk factors were reported for group 1: non-specific low back pain (smoking, overweight/obesity, negative recovery expectations), non-specific neck pain (high job demands, monotonous work); group 2: degenerative spinal disease (workers' compensation claim, degenerative scoliosis), and group 3: spinal tuberculosis (age, imprisonment, previous history of tuberculosis), spinal cord injury (age, accidental injury), vertebral fracture from osteoporosis (type 1 diabetes, certain medications, smoking), and neural tube defects (folic acid deficit, anti-convulsant medications, chlorine, influenza, maternal obesity). A range of comorbidities was identified for spinal disorders.
Many associated factors for common spinal disorders identified in this study are modifiable. The most common spinal disorders are co-morbid with general health conditions, but there is a lack of clarity in the literature differentiating which conditions are merely comorbid versus ones that are risk factors. Modifiable risk factors present opportunities for policy, research, and public health prevention efforts on both the individual patient and community levels. Further research into prevention interventions for spinal disorders is needed to address this gap in the literature.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This work aims to study the effect of addition of photocatalyst on the characteristics of TiO2 modified mortars and the influence of type of binder, surface roughness and microstructure, on their ...photoactivity for self-cleaning of organic dyes (rhodamine B and methylene blue) and NOx degradation. Mortars with four different types of cements and three levels of roughness were prepared. From the results, it was found that the available active surface is a parameter more influential than surface roughness for assessing photocatalytic efficiency. Concerning the composition of the mixes, the classification according to photocatalytic efficiency was the same for both NOx and self-cleaning, being, in decreasing order: Portland cement (quite similar to calcium aluminate cement for NOx), fly ash and slag mortars. The difference has been explained on the basis of oxidation-reduction potentials and photoabsorption energy of the different constituents of cementitious matrix.
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•Combination of TiO2 with cement binders leads to inclusion of energetic disorders.•Energetic disorders in the TiO2 cement samples leads to energetic tail bands.•Ti+3 or oxygen ...vacancies energetic disorders appear in TiO2 cement samples.•Energetic disorders in TiO2 cement materials can enhance the photoactivity.
Different mortar mixes using TiO2 P25 as photocatalyst have been prepared. The samples were characterized by UV–vis spectroscopy, X-ray photoelectron spectroscopy and Photoluminiscence spectroscopy. Also, determination of hydroxyl radicals and degradation tests of NOx under visible and UV light have been performed. The results obtained have allowed determining the band edges, Urbach energies and valence band tail sizes, directly related to the energy levels present in the TiO2-cement based materials. Therefore, the schema of the electronic structures of the reference TiO2-photocatalyst and the three TiO2-cement based samples have been constructed. The photocatalytic efficiency has been evaluated according to these energy levels, being able to conclude that in some cases, as the mortar with slags, the chemical composition seems to prevail over the effect of the optical parameter and electronic band structure.
In this paper a procedure for selecting the enhancing solutions in electrokinetic remediation experiments is proposed. For this purpose, dredged marine sediment was contaminated with fuel, and a ...total of 22 different experimental conditions were tested, analysing the influence of different enhancing solutions by using three commercial non-ionic surfactants, one bio-surfactant, one chelating agent, and one weak acid. Characterisation, microelectrophoretic and electrokinetic remediation trials were carried out. The results are explained on the basis of the interactions between the fuel, the enhancing electrolytes and the matrix. For one specific system, the electrophoretic zeta potential, (ζ), of the contaminated matrix in the solution was found to be related to the electroosmotic averaged ζ in the experiment and not to the efficiency in the extraction. This later was correlated to a parameter accounting for both contributions, the contaminant and the enhancing solution, calculated on the basis of differences in the electrophoretic ζ in different conditions which has allowed to propose a methodology for selection of enhancing solutions.
•Design of electrokinetic remediation for fuel contaminated sediments is undertaken.•It has been proposed a methodology for selection of enhancing solutions.•Different interactions are evaluated by changes in zeta potential.•Efficiency in remediation is correlated with electrophoretic measurements.
Photocatalytic technology implemented in construction materials is a promising solution to contribute to alleviate air quality issues found in big cities. Photocatalysis has been proved able to ...mineralise most harmful contaminants. However, important problems associated with monitoring the efficiency of these solutions under real conditions still remain, including the lack of affordable analytical tools to measure NOx concentrations with enough accuracy. In this work, two pilot scale demonstration platforms were built at two different locations to assess the photocatalytic NOX removal efficiency of ten selected materials exposed outdoors for AQmesh low-cost sensor PODs were used to measure ground-level to measure NO and NO2 concentrations during nearly one year. The pollutant removal efficiency of the materials was then calculated based on a comparison with simultaneously concentration measurements carried-out on reference, non-active materials. It was found that the NO2 removal efficiency presented large variations across the seasons, with maxima during the warmer months, while NO efficiencies were comparatively steadier. Statistical analysis delivered evidence that the efficiencies significantly depend on different meteorological variables (irradiance and relative humidity) besides NO, NO2 ambient concentrations. Lower efficiencies were observed for higher concentration levels and vice versa. The influence of water vapour could be related to two different effects: a short-term contribution by the instantaneous air humidity and a long-term component associated with the hygroscopic state of the material. The contribution of wind to the pollutant removal efficiencies was principally related to the humidity of air masses moving above the location and to the advection of pollutants from specific emission sources.
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•10 commercial photocatalytic pavements tested at pilot scale during 1 year•Measurements from low cost sensors post-processed by means of ML algorithms•Effect on NOx removal efficiencies of environmental variables assessed through GAMs•Removal efficiencies increase significantly as pollutant concentrations decrease.•Hygroscopic state of the material is a highly influential parameter for NO2 removal.
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