The increasing use of oxide nanoparticles (NPs) in commercial products has intensified the potential release into the aquatic environment where algae represent the basis of the trophic chain. NP ...effects upon algae population growth were indeed already reported in literature, but the concurrent effects at cellular and genomic levels are still largely unexplored.
Our work investigates the genotoxic (by COMET assay) and cytotoxic effects (by qualitative ROS production and cell viability) of ZnO nanoparticles toward marine microalgae Dunaliella tertiolecta. A comparison at defined population growth inhibition levels (i.e. 50% Effect Concentration, EC50, and No Observed Effect Concentration, NOEC) with SiO2 and TiO2 genotoxic effects and previously investigated cytotoxic effects (Manzo et al., 2015) was performed in order to elucidate the possible diverse mechanisms leading to algae growth inhibition.
After 72h exposure, ZnO particles act firstly at the level of cell division inhibition (EC50: 2mg Zn/L) while the genotoxic action is evident only starting from 5mg Zn/L. This outcome could be ascribable mainly to the release of toxic ions from the aggregate of ZnO particle in the proximity of cell membrane.
In the main, at EC50 and NOEC values for ZnO NPs showed the lowest cytotoxic and genotoxic effect with respect to TiO2 and SiO2. Based on Mutagenic Index (MI) the rank of toxicity is actually: TiO2>SiO2>ZnO with TiO2 and SiO2 that showed similar MI values at both NOEC and EC50 concentrations.
The results presented herein suggest that up to TiO2 NOEC (7.5mg/L), the algae DNA repair mechanism is efficient and the DNA damage does not result in an evident algae population growth inhibition. A similar trend for SiO2, although at lower effect level with respect to TiO2, is observable.
The comparison among all the tested nanomaterial toxicity patterns highlighted that the algae population growth inhibition occurred through pathways specific for each NP also related to their different physicochemical behaviors in seawater.
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•ZnO (nano) particles act firstly at level of cell division inhibition.•ZnO genotoxic action is evident only starting from 5mg Zn/L.•The ZnO toxicity can be due mainly but not solely to the release of toxic ions.•At algae NOEC and EC50 the rank of genotoxicity is: TiO2>SiO2>ZnO.•SiO2 and TiO2 show different pathways leading to algae population growth inhibition.
In the last years, applications for silver nanoparticles (Ag NPs) continue to increase together with the concerns about their potential input and hazards in aquatic ecosystems, where microalgae are ...key organisms. The aim of the present study was to assess the relative sensitivity of three marine microalgae species with differences in cell wall composition/structure exposed to Poly N-vinyl-2-pirrolidone/Polyethyleneimine (PVP/PEI) coated 5nm Ag NPs and uncoated 47nm Ag NP. As limited attention has been paid to the role of coating agents in NP toxicity, the effect of PVP/PEI alone was also evaluated. After 72h in artificial seawater, 47nm Ag NPs formed around 1400nm size aggregates while PVP/PEI coated 5nm Ag NPs reached around 90nm. Ag+ release in seawater was around 3% for 47nm Ag NPs and 30% for PVP/PEI coated 5nm Ag NPs. PVP/PEI coated 5nm Ag NP aggregates entrapped the algal cells in a network of heteroaggregates, while uncoated 47nm Ag NPs interacted to a lesser extent with algae. The concentration of PVP/PEI coated 5nm Ag NPs that exerted the median effect (EC50) on algae growth pointed out differences in algae sensitivity: T. suecica was about 10 times more sensitive than I. galbana and P. tricornutum. Further, the coating agent alone was as toxic to algae as PVP/PEI coated 5nm Ag NPs, suggesting that presence of the coating agent was the main driver of toxicity of coated NPs. Uncoated 47nm Ag NPs instead, showed similar toxicity towards algae although P. tricornutum was slightly less sensitive than T. suecica and I. galbana, which agrees with the presence of a resistant silicified cell wall in the diatom. The present work demonstrates differences in sensitivity of three marine microalgae, possibly related to their cell surface and size characteristics.
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•Effects of coated, uncoated Ag NPs and coating agent on microalgae were evaluated.•Coated 5 nm Ag NPs produced aggregates of smaller size and released 10 times more Ag ions than uncoated 47 nm Ag NPs.•Coated 5 nm Ag NPs were more toxic than uncoated 47 nm Ag NPs.•The coating agent alone was as toxic as coated 5 nm Ag NPs.•Tetraselmis suecica was about 10 times more sensitive than Isochrysis galbana and Phaeodactylum tricornutum.
Nanoparticles (NPs) are widely used in many industrial applications. NP fate and behavior in seawater are a very important issue for the assessment of their environmental impact and potential ...toxicity. In this study, the toxic effects of two nanomaterials, silicon dioxide (SiO
2
) and titanium dioxide (TiO
2
) NPs with similar primary size (~20 nm), on marine microalgae
Dunaliella tertiolecta
were investigated and compared. The dispersion behavior of SiO
2
and TiO
2
NPs in seawater matrix was investigated together with the relative trend of the exposed algal population growth. SiO
2
aggregates rapidly reached a constant size (600 nm) irrespective of the concentration while TiO
2
NP aggregates grew up to 4 ± 5 μm. The dose–response curve and population growth rate alteration of marine alga
D. tertiolecta
were evaluated showing that the algal population was clearly affected by the presence of TiO
2
NPs. These particles showed effects on 50 % of the population at 24.10 19.38–25.43 mg L
−1
(EC50) and a no observed effect concentration (NOEC) at 7.5 mg L
−1
. The 1 % effect concentration (EC1) value was nearly above the actual estimated environmental concentration in the aquatic environment. SiO
2
NPs were less toxic than TiO
2
for
D. tertiolecta
, with EC50 and NOEC values one order of magnitude higher. The overall toxic action seemed due to the contact between aggregates and cell surfaces, but while for SiO
2
a direct action upon membrane integrity could be observed after the third day of exposure, TiO
2
seemed to exert its toxic action in the first hours of exposure, mostly via cell entrapment and agglomeration.
Neuroplasticity and recovery after stroke can be enhanced by a rehabilitation program pertinent to upper limb motor function exercise and mental imagery (EMI) as well as hyperbaric oxygen therapy ...(HBOT). We assessed feasibility and safety of the combined approach utilizing both HBOT and EMI, and to derive preliminary estimates of its efficacy. In this randomized controlled trial, 27 patients with upper extremity hemiparesis at 3–48 months after stroke were randomized to receive either a complementary rehabilitation program of HBOT-EMI (intervention group), or EMI alone (control group). Feasibility and safety were assessed as total session attendance, duration of sessions, attrition rates, missing data, and intervention-related adverse events. Secondary clinical outcomes were assessed with both objective tools and self-reported measures at baseline, 8 weeks (end of treatment), and 12-weeks follow-up. Session attendance, duration, and attrition rate did not differ between the groups; there were no serious adverse events. Compared with baseline, there were significant sustained improvements of objective and subjective outcomes’ measures in the intervention group, and a single improvement in an objective measure in the control group. Between-group outcome comparisons were not statistically significant. This study demonstrated that the combination HBOT-EMI was a safe and feasible approach in patients recovering from chronic stroke. There were also trends for improved motor function of the affected upper limb after the treatments. ClinicalTrials.gov registration no.: NCT02666469.
Novelty
HBOT combined with an upper limb exercise and mental imagery rehabilitation program is feasible and safe in chronic stroke patients.
This combined approach showed trends for improved functional recovery.
Summary
A 5‐year‐old National Hunt Thoroughbred mare presented with sudden onset left hindlimb lameness after race training on the gallops. Clinical examination revealed a marked painful reaction ...over the proximal metatarsal region but no other obvious abnormalities were detected. Survey radiographs at the yard did not reveal any abnormalities. Nuclear scintigraphic examination 3 days after injury revealed focal marked increased radiopharmaceutical uptake in the proximal metatarsal region. Subsequent radiography revealed an incomplete, articular fracture of the proximal left third metatarsal bone. Repair of the fracture using 3 × 4.5 mm cortical screws placed in lag fashion was performed under standing sedation following perineural analgesia. Follow‐up radiographs demonstrated progressive healing of the fracture. The mare returned to race training 8 months after the fracture was repaired and raced successfully 12 months post injury.
Although the biodegradability of compostable bioplastic bags (CBBs) is well ascertained, concerns arise about the possibility of treating a massive quantity of compostable materials in composting ...facilities of all sizes and configurations. These concerns are even greater in small-scale composting where the biodegrading conditions may be milder that those in industrial composting. In this work, 7–15 lightweight CBBs were disposed of, together with organic food waste, in an electromechanical composter (EMC), every day for about 2 months. For the bulking agent, fragments and twigs of golden wattle wood were used instead of the recommended wood pellets. The composting process was carried out for 3 months in the EMC, and for further 4 months in a heap, in order to complete the maturation. During the process, critical issues in general, and any due to the presence of the CBBs, were reported: high temperatures, up to 72 °C, were constantly reached both in the ECM and in the heap, while critical anaerobic pockets were not detected. After 7 months, when the temperature and pH of the heap were equal to the ambient temperature and to 7.4, respectively, and were constant over time, the process was stopped and the compost produced underwent chemical, physical and biological analysis, in order to evaluate its quality. The CBBs did not produce any visual contamination of the final compost with bioplastic residues. Finally, all the stability, environmental and agronomic parameters were in compliance with the reference values established by law. This work shows how lightweight CBBs are perfectly managed by the EMC, at least with a CBB/organic waste mass ratio that is consistent with a normal use of CBBs as the collector of organic waste.
Graphical abstract
In this paper we adopt both a nonparametric and a semiparametric IV estimator to show that the relationship between inflation and output growth is non-linear and that there exists a threshold level ...below which inflation has no effects on growth.
The reaction of the epoxy derivatives 2-(3,4-epoxycyclohexyl)ethyl-trimethoxysilane (ECET) and (3-glycidyloxypropyl)methyldiethoxysilane (GLYMS) with the primary amine (3-aminopropyl)triethoxysilane ...(ATS) leads to solids that have been investigated by means of TG-DTA, FT-Raman and FT-IR spectroscopy. Solution
13C NMR and solid state FT-Raman spectra show that the oxirane ring of ECET is not involved in the epoxy-amine addition. The structure of the resulting materials consists of a siloxane network with pendant epoxycyclohexyl groups. On the contrary, when GLYMS is allowed to react with ATS, the polymeric network develops either on the organic as on the inorganic side so that the resulting materials may be viewed as silica-epoxy hybrids with organic polymer chains covalently linked to inorganic domains. Porosity, water absorption properties and dynamic contact angle measurements were used to preliminarily evaluate the efficacy of the above materials as conservation products.
Background/aims
: While Angiotensin II (Ang II) is a major factor in the development of cardiomyocyte hypertrophy and a pivotal role for Ang II signals via ERK1/2 has been identified, mechanism(s) ...responsible are still unclear. As Bartter’s and Gitelman’s syndrome patients (BS/GS) have increased Ang II, and yet normo/hypotension, hyporesponsiveness to pressors and blunted Ang II signaling via type 1 receptors (AT1R), this study assesses BS/GS’s left ventricular (LV) mass and structure as well as Ang II induced ERK1/2 phosphorylation compared with essential hypertensive patients (EH) and normotensive healthy subjects (C) to gain insight into Ang II mediated processes.
Methods
: Indices of cardiac hypertrophy were determined by M-mode, two-dimensional echo Doppler and ERK phosphorylation by Western blot.
Results
: None of BS/GS exhibited LV remodelling; LV mass, LV end-diastolic volume and mass/volume ratio were unchanged
vs
C (60±14 g/m
2
vs
64±12, 64±12 ml/m
2
vs
60±8 and 0.95±0.2
vs
1.0±0.2, respectively) and reduced
vs
EH (119±15, p<0.001, 78±9, p<0.05 and 1.52±0.15, p<0.01). Despite BS/GS’s higher plasma renin activity and aldosterone and unchanged level of AT1R, Ang II induced ERK1/2 phosphorylation was reduced
vs
both C and EH: 0.64 d.u.±0.08
vs
0.90±0.06 in C, p<0.006, and
vs
1.45±0.07 in EH, p<0.001.
Conclusion
: The data point to a direct cardioremodeling role for Ang II and support a role of Ang II type 2 receptor (AT2R) signaling as involved in the lack of cardiovascular remodeling in BS/GS. However, further studies using more direct approaches to demonstrate the effects of AT2R signaling must be pursued.
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