4,562 research outputs found
Assessment of landfill leachate biodegradability and treatability by means of allochthonous and autochthonous biomasses
The biodegradability and treatability of a young (3 years old) municipal landfill leachate was evaluated by means of chemical oxygen demand (COD) fractionation tests, based on respirometric techniques. The tests were performed using two different biomasses: one cultivated from the raw leachate (autochthonous biomass) and the other collected from a conventional municipal wastewater treatment plant after its acclimation to leachate (allochthonous biomass). The long term performances of the two biomasses were also studied. The results demonstrated that the amount of biodegradable COD in the leachate was strictly dependent on the biomass that was used to perform the fractionation tests. Using the autochthonous biomass, the amount of biodegradable organic substrate resulted in approximately 75% of the total COD, whereas it was close to 40% in the case of the allochthonous biomass, indicating the capacity of the autochthonous biomass to degrade a higher amount of organic compounds present in the leachate. The autochthonous biomass was characterized by higher biological activity and heterotrophic active fraction (14% vs 7%), whereas the activity of the allochthonous biomass was significantly affected by inhibitory compounds in the leachate, resulting in a lower respiration rate (SOUR = 13 mg O2 gVSS-1 h-1 vs 37 mg O2 gVSS-1 h-1). The long-term performance of the autochthonous and allochthonous biomasses indicated that the former was more suitable for the treatment of raw landfill leachate, ensuring higher removal performance towards the organic pollutants
Direct measurement of DNA-mediated adhesion between lipid bilayers
Multivalent interactions between deformable mesoscopic units are ubiquitous
in biology, where membrane macromolecules mediate the interactions between
neighbouring living cells and between cells and solid substrates. Lately,
analogous artificial materials have been synthesised by functionalising the
outer surface of compliant Brownian units, for example emulsion droplets and
lipid vesicles, with selective linkers, in particular short DNA sequences. This
development extended the range of applicability of DNA as a selective glue,
originally applied to solid nano and colloidal particles. On very deformable
lipid vesicles, the coupling between statistical effects of multivalent
interactions and mechanical deformation of the membranes gives rise to complex
emergent behaviours, as we recently contributed to demonstrate [Parolini et
al., Nature Communications, 2015, 6, 5948]. Several aspects of the complex
phenomenology observed in these systems still lack a quantitative experimental
characterisation and fundamental understanding. Here we focus on the
DNA-mediated multivalent interactions of a single liposome adhering to a flat
supported bilayer. This simplified geometry enables the estimate of the
membrane tension induced by the DNA-mediated adhesive forces acting on the
liposome. Our experimental investigation is completed by morphological
measurements and the characterisation of the DNA-melting transition, probed by
in-situ F\"{o}rster Resonant Energy Transfer spectroscopy. Experimental results
are compared with the predictions of an analytical theory that couples the
deformation of the vesicle to a full description of the statistical mechanics
of mobile linkers. With at most one fitting parameter, our theory is capable of
semi-quantitatively matching experimental data, confirming the quality of the
underlying assumptions.Comment: 16 pages, 7 figure
Dermoscopy and methyl aminolevulinate: A study for detection and evaluation of field cancerization
Actinic keratosis (AK) is a keratinocyte intraepidermal neoplasia UV light
–
induced that frequently appears in
sun-exposed areas of the skin. Although historically AK was de
fi
ned as
“
precancerous
”
, actually it is considered
as the earliest stage of squamous cell carcinoma (SCC) in situ. Since AKs can progress into invasive SCC, their
treatment isrecommended. AKsrarely developasa singlelesion;usually multiplelesions commonly affect anen-
tire area of chronically actinic damaged skin. This has led to the concept of
“
fi
eld cancerization
”
, an area chroni-
cally sun-exposed that surrounds peripherally visible lesions, in which are individualized subclinical alterations.
One of the main principles endpoint in the management of AKs is the evaluation and the treatment of
fi
eld
cancerization. In this view, in order to detect and quantify
fi
eld cancerization, we employed a method based
on the topical application of methyl aminolevulinate (MAL) and the detection of the
fl
uorescence emitted by
its metabolite Protoporphyrin IX (PpIX); then, considering the extension and the intensity of measured
fl
uores-
cence, we create a score of
fi
eld cancerization. The results show that patients underwent to daylight PDT had a
reduction of total score, from T0 to T2. Whereas in the group untreated we observed a stability of total score or
a slightly worse. So, the method and the score used allows to evaluate with a good approximation the dimension
of
fi
eld cancerization and show the modi
fi
cation of it after treatment
Ultrasound-assisted synthesis of WOx-decorated ZnO photocatalysts for NOx abatement
Heterojunctions based on ZnO have numerous applications, such as water splitting, sensing and energy storage [1]. Recently, ZnO/WO3 composites have shown promising results in the sonocatalytic and photocatalytic degradation of aqueous and gas pollutants [2]. Several synthetic approaches have been reported, including chemical vapor deposition, magnetron sputtering, hydrothermal methods and high temperature annealing. Ultrasound-assisted synthesis can provide a scalable and cost-effective strategy to tailor the catalyst structural and morphological properties [3]. In the present work, pristine ZnO and ZnO/WOx composites were synthesized via a sonochemical method, studying the role of the ultrasound amplitude and mode (continuous/pulsed), metal precursor, WOx content and post-synthetic annealing. The resulting materials were extensively characterized, investigating their structural, morphological, optical, and surface properties. Samples were tested towards the photocatalytic removal of NOx under both UV and visible light irradiation in a batch reactor. A good degree of crystallinity is appreciable even before calcination and better morphological features are observed with respect to reference samples prepared without ultrasounds. The morphological properties can be further tuned by changing the metal precursor and adding a post-synthetic annealing step. Photocatalytic activity is promoted with respect to both benchmark samples (Figure 1)
Monster black holes
A combination of ground-based and spacecraft observations has uncovered two
black holes of 10 billion solar masses in the nearby Universe. The finding
sheds light on how these cosmic monsters co-evolve with galaxies.Comment: 2 pages, 1 figure, LaTeX. Published in Nature "News & Views
Seasonal Training-Load Quantification in Elite English Premier League Soccer Players
Purpose: To quantify the seasonal training load completed by professional soccer players of the English Premier League. Methods: Thirty players were sampled (using GPS, heart rate, and rating of perceived exertion [RPE]) during the daily training sessions of the 2011–12 preseason and in-season period. Preseason data were analyzed across 6 × 1-wk microcycles. In-season data were analyzed across 6 × 6-wk mesocycle blocks and 3 × 1-wk microcycles at start, midpoint, and end-time points. Data were also analyzed with respect to number of days before a match. Results: Typical daily training load (ie, total distance, high-speed distance, percent maximal heart rate [%HRmax], RPE load) did not differ during each week of the preseason phase. However, daily total distance covered was 1304 (95% CI 434–2174) m greater in the 1st mesocycle than in the 6th. %HRmax values were also greater (3.3%, 1.3–5.4%) in the 3rd mesocycle than in the first. Furthermore, training load was lower on the day before match (MD-1) than 2 (MD-2) to 5 (MD-5) d before a match, although no difference was apparent between these latter time points. Conclusions: The authors provide the 1st report of seasonal training load in elite soccer players and observed that periodization of training load was typically confined to MD-1 (regardless of mesocycle), whereas no differences were apparent during MD-2 to MD-5. Future studies should evaluate whether this loading and periodization are facilitative of optimal training adaptations and match-day performance
Sarcopenia: age-related skeletal muscle changes from determinants to physical disability.
Human aging is characterized by skeletal muscle wasting, a debilitating condition which sets the susceptibility for diseases that directly affect the quality of life and often limit life span. Sarcopenia, i.e. the reduction of muscle mass and/or function, is the consequence of a reduction of protein synthesis and an increase in muscle protein degradation. In addition, the capacity for muscle regeneration is severely impaired in aging and this can lead to disability, particularly in patients with other concomitant diseases or organ impairment. Immobility and lack of exercise, increased levels of proinflammatory cytokines, increased production of oxygen free radicals or impaired detoxification, low anabolic hormone output, malnutrition and reduced neurological drive have been advocated as being responsible for sarcopenia. It is intriguing to notice that multiple pathways converge on skeletal muscle dysfunction, but the factors involved sometimes diverge to different pathways, thus intersecting at critical points. It is reasonable to argue that the activity of these nodes results from the net balance of regulating mechanisms, as in the case of the GH/IGF-1 axis, the testosterone and Cortisol functions, the pro- and anti-inflammatory cytokines and receptors. Both genetic and epigenetic mechanisms operate in regulating the final phenotype, the extent of muscle atrophy and reduction in strength and force generation. It is widely accepted that intervention on lifestyle habits represents an affordable and practical way to modify on a large scale some detrimental outcomes of aging, and particularly sarcopenia. The identification of the molecular chain able to reverse sarcopenia is a major goal of studies on human aging
Training Load and Carbohydrate Periodization Practices of Elite Male Australian Football Players: Evidence of Fueling for the Work Required.
The authors aimed to quantify (a) the periodization of physical loading and daily carbohydrate (CHO) intake across an in-season weekly microcycle of Australian Football and (b) the quantity and source of CHO consumed during game play and training. Physical loading (via global positioning system technology) and daily CHO intake (via a combination of 24-hr recall, food diaries, and remote food photographic method) were assessed in 42 professional male players during two weekly microcycles comprising a home and away fixture. The players also reported the source and quantity of CHO consumed during all games (n = 22 games) and on the training session completed 4 days before each game (n = 22 sessions). The total distance was greater (p < .05) on game day (GD; 13 km) versus all training days. The total distance differed between training days, where GD-2 (8 km) was higher than GD-1, GD-3, and GD-4 (3.5, 0, and 7 km, respectively). The daily CHO intake was also different between training days, with reported intakes of 1.8, 1.4, 2.5, and 4.5 g/kg body mass on GD-4, GD-3, GD-2, and GD-1, respectively. The CHO intake was greater (p < .05) during games (59 ± 19 g) compared with training (1 ± 1 g), where in the former, 75% of the CHO consumed was from fluids as opposed to gels. Although the data suggest that Australian Football players practice elements of CHO periodization, the low absolute CHO intakes likely represent considerable underreporting in this population. Even when accounting for potential underreporting, the data also suggest Australian Football players underconsume CHO in relation to the physical demands of training and competition
The effect of acute caffeine ingestion on physical performance in elite European competitive soccer match-play
The present study examined the effect of acute caffeine ingestion (150 mg) on the physical performance of elite
European soccer players during official competitive match-play. The current investigation was a parallel-group design
that collated data from a cohort of 19 male outfield players from an elite European soccer team (mean ± SD, age 26 ±
4 years; weight 80.5 ± 8.1 kg; height 1.83 ± 0.07 m; body-fat 10.8 ± 0.7%). Players were classified and matched by
position and grouped accordingly: centre defender (CD) n = 5, wide defender (WD) n = 3, centre midfield (CM) n = 7,
wide forward (WF) n = 2, and centre forward (CF) n = 2. For all performance variables, the mean values were compared
in caffeine consumers vs. non consumers using independent-sample t-tests, with significance set at p < .05. Cohen’s
d was used to quantify the effect size, and was interpreted as trivial (<0.2), small (0.2-0.5), medium (0.5-0.8), and large
(>0.8). For all examined variables, there were trivial or small non-significant (p > .05) trivial or small differences between
caffeine consumers and non-consumers. The findings of the present research did not confirm the study hypothesis,
once running and accelerometry-based variables did not improve with the caffeine ingestion of 150 mg. Therefore, the
caffeine supplement used in this study is not suggested for improving performance in the variables analysed
Computational modelling of emboli travel trajectories in cerebral arteries: Influence of microembolic particle size and density
This article has been made available through the Brunel Open Access Publishing Fund.Ischaemic stroke is responsible for up to 80 % of stroke cases. Prevention of the reoccurrence of ischaemic attack or stroke for patients who survived the first symptoms is the major treatment target. Accurate diagnosis of the emboli source for a specific infarction lesion is very important for a better treatment for the patient. However, due to the complex blood flow patterns in the cerebral arterial network, little is known so far of the embolic particle flow trajectory and its behaviour in such a complex flow field. The present study aims to study the trajectories of embolic particles released from carotid arteries and basilar artery in a cerebral arterial network and the influence of particle size, mass and release location to the particle distributions, by computational modelling. The cerebral arterial network model, which includes major arteries in the circle of Willis and several generations of branches from them, was generated from MRI images. Particles with diameters of 200, 500 and 800 μ m and densities of 800, 1,030 and 1,300 kg/m 3 were released in the vessel's central and near-wall regions. A fully coupled scheme of particle and blood flow in a computational fluid dynamics software ANASYS CFX 13 was used in the simulations. The results show that heavy particles (density large than blood or a diameter larger than 500 μ m) normally have small travel speeds in arteries; larger or lighter embolic particles are more likely to travel to large branches in cerebral arteries. In certain cases, all large particles go to the middle cerebral arteries; large particles with higher travel speeds in large arteries are likely to travel at more complex and tortuous trajectories; emboli raised from the basilar artery will only exit the model from branches of basilar artery and posterior cerebral arteries. A modified Circle of Willis configuration can have significant influence on particle distributions. The local branch patterns of internal carotid artery to middle cerebral artery and anterior communicating artery can have large impact on such distributions. © 2014 The Author(s)
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