The degradation and detoxification towards the duckweed Lemna minor of 4-nitrophenol (4NP) was studied by means of bench-scale constructed wetlands (CWs), TiO2-photocatalysis and Fenton + photoFenton ...reactions. The main goal of this work was to compare the three treatment techniques to evaluate their possible combination for the efficient, low cost treatment of 4NP effluents. In CWs, adsorption on the substrate of 4NP was found to achieve 34–45%. Low concentrations (up to 100 ppm) of 4NP were successfully treated by CWs in 8–12 h. The microbial degradation of 4NP started after a lag phase which was longer with higher initial concentrations of the pollutant. The greatest degradation rate was found to occur at initial concentrations of 4NP between 60 and 90 ppm. Solar TiO2-photocatalysis was faster than the CWs. The greatest removals in terms of mass of 4NP removed after 6 h of irradiation were found to occur at 4NP concentrations of about 200 ppm. Fenton reaction provided complete 4NP degradation up to 500 ppm in only 30 min but TOC was removed by only about 40%. The resulting toxicities were below 20% for initial 4NP concentrations below 300 ppm. It was the Fenton + photoFenton combination (180 min in total) that provided TOC reductions up to 80% and negative L. minor growth inhibition for almost all the 4NP concentrations tested. The combination of solar TiO2-photocatalysis (6 h) with CWs (16 h) was able to completely treat and detoxify 4NP effluents with concentrations as high as 200 ppm of the organic.
► We studied the treatment 4NP by CWs and advanced oxidation technologies. ► In CWs biodegradation and adsorption were the main removal pathways. ► The 4NP removal order was: CWs < TiO2-photocatalysis < Fenton–photoFenton. ► The combination of CWs with photocatalysis is proposed as a convenient treatment.
► ECT-1023t showed higher photocatalytic activity than commercial P25 on both 2,4-D and bentazon. ► Production of toxic of intermediates (2,4-DCP) was reduced by using ECT-1023t. ► Sedimentation of ...ECT-1023t was slightly faster than of commercial P25 at natural pH.
A comparative study of the photocatalytic activity of two different TiO2 catalysts in solar photocatalytic oxidation, mineralization and detoxification of waters containing herbicides 2,4-dichlorophenoxyacetic acid (2,4-D), bentazon and toxic intermediates was performed in a pilot plant scale photoreactor. Commercial TiO2 (Degussa P25) and TiO2 synthesized by citrate sol–gel method (ECT-1023t) were selected as photocatalysts. The optimal basic operational parameters to eliminate these herbicides and toxic intermediates were established for both catalysts at laboratory scale. ECT-1023t showed better photocatalytic activity than the commercial Degussa P25 at solar pilot plant scale with both herbicides in real water at natural pH (6.8–7.8) without any additive. The toxicity of the treated solutions was evaluated using the Microtox test based on the inhibition of bioluminescence of the bacteria Vibrio fischeri. The toxic effect of the main intermediate of 2,4-D, the 2,4-dichlorophenol (2,4-DCP), was higher than the parental herbicide. Acute toxicity of 2,4-D and intermediates (2,4-DCP) was reduced during the photocatalytic treatment by using ECT-1023t as photocatalyst. Longer times were necessary to obtain similar results when using P25 as photocatalyst. No inhibitory growth effect of the herbicide bentazon and its photoproducts on Vibrio fischeri bacteria bioluminescence was observed for either photocatalyst in any of the irradiated samples collected at predetermined times using an initial concentration of 0.1325mM of the herbicide.
Extracellular vesicles are produced by many pathogenic microorganisms and have varied functions that include secretion and release of microbial factors, which contribute to virulence. Very little is ...known about vesicle production by Gram-positive bacteria, as well as their biogenesis and release mechanisms. In this work, we demonstrate the active production of vesicles by Streptococcus pneumoniae from the plasma membrane, rather than being a product from cell lysis. We biochemically characterized them by proteomics and fatty acid analysis, showing that these vesicles and the plasma membrane resemble in essential aspects, but have some differences: vesicles are more enriched in lipoproteins and short-chain fatty acids. We also demonstrate that these vesicles act as carriers of surface proteins and virulence factors. They are also highly immunoreactive against human sera and induce immune responses that protect against infection. Overall, this work provides insights into the biology of this important Gram-positive human pathogen and the role of extracellular vesicles in clinical applications.
Pneumococcus is one of the leading causes of bacterial pneumonia worldwide in children and the elderly, being responsible for high morbidity and mortality rates in developing countries. The augment of pneumococcal disease in developed countries has raised major public health concern, since the difficulties to treat these infections due to increasing antibiotic resistance. Vaccination is still the best way to combat pneumococcal infections. One of the mechanisms that bacterial pathogens use to combat the defense responses of invaded hosts is the production and release of extracellular vesicles derived from the outer surface. Little is known about this phenomenon in Gram-positives. We show that pneumococcus produces membrane-derived vesicles particularly enriched in lipoproteins. We also show the utility of pneumococcal vesicles as a new type of vaccine, as they induce protection in immunized mice against infection with a virulent strain. This work will contribute to understand the role of these structures in important biological processes such as host-pathogen interactions and prevention of human disease.
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•Pneumococcus produces membrane vesicles that are released to the milieu.•Proteomics show that they are more enriched in lipoproteins than the cell membrane.•Membrane vesicles induce protection against pneumococcal infection in mice.
Sperm are redox-regulated cells, and deregulation of their redox status is considered to affect male fertility and to reduce their fertilizing ability following biotechnological procedures, such as ...cryopreservation. Cystine (CysS), after incorporation in sperm via SLC7A11 antiporter, has been demonstrated to increase intracellular GSH content, the most important non enzymatic antioxidant. This study was aimed at investigating the role of SLC7A11 antiporter on frozen-thawed stallion sperm ability to respond to in vitro capacitating environment after post-thaw incubation with CysS and/or Sulfasalazine (SS), a specific inhibitor of SLC7A11 antiporter. Viability, motility, immunolocalization of tyrosine phosphorylated proteins and the ability to bind to heterologous zonae pellucidae were evaluated. Thawed sperm from seven stallions (2 ejaculates/stallion) was washed and resuspended in Tyrodes media; each thawed ejaculate was divided in Control (CTR) and 3 samples supplemented with: 0.5 mM Cystine (CysS), 500 μM Sulfasalazine (SS) and 0.5 mM CysS + 500 μM SS (CysS + SS). After 1 h of incubation at 37 °C, samples were washed twice, resuspended in capacitating BWW medium and incubated at 38 °C under 5% CO2. After 30 and 60 min, sperm motility, viability and tyrosine phosphorylated protein immunolocalization, used as capacitation status index, were evaluated. After 30 min of capacitation, 4 × 105 sperm were co-incubated with denuded pig oocytes in capacitation medium for 30 min for the heterologous binding assay. None of the sperm parameters studied (motility, viability and tyrosine phosphorylation) showed any difference respective to control. The number of sperm bound per oocyte (mean ± SEM) tended to increase in CysS group (44.0 ± 12.3) respect CTR (40.8 ± 10.8) while decreased in SS group (32.4 ± 7.8) (p < 0.01). Moreover, CysS + SS group showed a lower binding rate (32.0 ± 10.0) compared to CysS (p < 0.001). Our results suggest that CysS supplementation of thawed stallion sperm can influence their ability to bind to heterologous zona pellucidae as the inhibition of CysS incorporation by SLC7A11 reduced the number of sperm bound per oocyte. This effect does not seem to be ascribed to a modification of sperm motility, membrane integrity and tyrosine phosphorylation.
•Cystine and/or sulfasalazine did not influence sperm viability and motility in thawed stallion sperm after capacitation.•Cystine and/or sulfasalazine did not affect tyrosine phosphorylation after sperm capacitation.•The inhibition of SCL7A11 antiporter significantly decreased the number of sperm bound to heterologous zonae pellucidae.
TiO2-based photocatalyst materials were synthesized through a sol–gel method, followed either by: (1) hydrothermal treatment (150 °C/24 h), or (2) heat treatment (calcination) in a temperature range ...between 400 and 900 °C. The resulting materials were characterized through BET, XRD, TEM, FTIR, RAMAN, laser diffraction and UV–Vis Diffuse Reflectance Spectroscopy. Photoactivity of the various materials was checked against photocatalytic water-splitting for hydrogen production and a relationship between TiO2 structure and hydrogen production capacity was identified. Optimum results were obtained for anatase-rutile mixtures in a ratio of 87:13. The activity of the home-made photocatalysts was also compared (under the same conditions) with the best commercially available materials which have been widely described in the literature: Hombikat UV100, Millenium PC100, Kronos vlp7000,Degussa P25and Kemira 625.
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► TiO2 photocatalysts were synthesized through a sol–gel and hydrothermal method. ► Home-made and commercial photocatalysts were tested against hydrogen production. ► Home-made photocatalysts are more active than pure titania commercial ones. ► Low percentages of rutile phase and 100% anatase encourage photoactivity. ► Kronos vlp7000 with surface carbon doping shows the highest hydrogen yield.
An epidemic of Coronavirus Disease 2019 (COVID-19) began in December 2019 in China leading to a Public Health Emergency of International Concern (PHEIC). Clinical, laboratory, and imaging features ...have been partially characterized in some observational studies. No systematic reviews on COVID-19 have been published to date.
We performed a systematic literature review with meta-analysis, using three databases to assess clinical, laboratory, imaging features, and outcomes of COVID-19 confirmed cases. Observational studies and also case reports, were included, and analyzed separately. We performed a random-effects model meta-analysis to calculate pooled prevalences and 95% confidence intervals (95%CI).
660 articles were retrieved for the time frame (1/1/2020-2/23/2020). After screening, 27 articles were selected for full-text assessment, 19 being finally included for qualitative and quantitative analyses. Additionally, 39 case report articles were included and analyzed separately. For 656 patients, fever (88.7%, 95%CI 84.5–92.9%), cough (57.6%, 95%CI 40.8–74.4%) and dyspnea (45.6%, 95%CI 10.9–80.4%) were the most prevalent manifestations. Among the patients, 20.3% (95%CI 10.0–30.6%) required intensive care unit (ICU), 32.8% presented with acute respiratory distress syndrome (ARDS) (95%CI 13.7–51.8), 6.2% (95%CI 3.1–9.3) with shock. Some 13.9% (95%CI 6.2–21.5%) of hospitalized patients had fatal outcomes (case fatality rate, CFR).
COVID-19 brings a huge burden to healthcare facilities, especially in patients with comorbidities. ICU was required for approximately 20% of polymorbid, COVID-19 infected patients and hospitalization was associated with a CFR of >13%. As this virus spreads globally, countries need to urgently prepare human resources, infrastructure and facilities to treat severe COVID-19.
Context.
In meteor physics, the luminous efficiency
τ
is used to convert the meteor’s magnitude to the corresponding meteoroid’s mass. However, a lack of sufficiently accurate verification methods or ...adequate laboratory tests mean that discussions around this parameter are a subject of controversy.
Aims.
In this work, we aim to use meteor data obtained by the Fireball Recovery and InterPlanetary Observation to calculate the luminous efficiencies of the recorded meteors. We also show the limitations of the methods presented herein.
Methods.
Deceleration-based formulas were used to calculate the masses of the pre-atmospheric meteoroids. These can in turn be compared to the meteor brightnesses to assess the luminous efficiencies of the recorded objects. Fragmentation of the meteoroids is not considered within this model. Good measurements of the meteor deceleration are required.
Results.
We find
τ
-values, as well as the shape change coefficients, of 294 meteors and fireballs with determined masses in the range of 10
−6
–100 kg. The derived
τ
-values have a median of
τ
median
= 2.17%. Most of them are of the order of 0.1–10%. We present how our values are obtained, compare them with data reported in the literature, and discuss several methods. A dependence of
τ
on the pre-atmospheric velocity of the meteor,
v
e
, is noticeable with a relation of τ = 0.0023⋅
v
e
2.3
. Furthermore, a dependence of
τ
on the initial meteoroid mass,
M
e
, is found with negative linear behaviour in log–log space: τ = 0.48⋅
M
e
−0.47
.
Conclusions.
The higher luminous efficiency of fast meteors could be explained by the higher amount of energy released. Fast meteoroids produce additional emission lines that radiate more efficiently in specific wavelengths due to the appearance of the so-called second component of higher temperature. Furthermore, the negative dependence of
τ
on
M
e
implies that the radiation of smaller meteoroids is more efficient. The results of this study also show the limitations of the ablation-based model for the determination of the luminous efficiency.
Abstract Background Donors after brain death (DBD) older than 60 years have become 46.8% of our current activity, with higher risk of renal discard rate (RDR). Assessment of kidney suitability ...requires complementary strategies: macroscopic evaluation, kidney biopsy score (KBS), and renal hemodynamic evaluation with the Pulsatile Perfusion Machine (PPM). Methods Descriptive, cross-sectional, comparative study of kidneys procured and RDR, comparing 3 time periods: 2000 to June 2004, when only KBS were used; July 2004 to 2008 (introduction of PPM and learning period); and 2009 to 2013 (experienced use of PPM). Transplantation criteria were KBS <3 and PPM renal resistance <0.4 mm Hg/mL/min and arterial renal flow >70 mL/min. Results Between 2000 and 2013, a 59.2% reduction in DBD kidneys was observed. However, older kidneys had an increase from 33.5% to 46.8%. The RDR had increased, comparing the first to the third period from 25.4% to 38.3%. However, the RDR was lower when kidneys were evaluated with PPM than those evaluated only with KBS and preserved in cold storage (CS) (21.4% versus 43.7%). There was a significant difference in cold ischemia time, because CS kidney was grafted before PPM. During the third period, more kidneys with KBS ≥4 were assigned to PPM. Conclusions Notwithstanding the decrease in DBD-procured kidneys and the increase in older kidneys during last period, the use of PPM allowed low DR compared with CS. A bias in the results of PPM could be generated when kidneys with higher KBS were excluded from PPM. The use of KBS only to decide acceptance could preclude the use of an additional tool to evaluate suitability.
Context.
The luminous efficiency,
τ
, can be used to compute the pre-atmospheric masses of meteoroids from corresponding recorded meteor brightnesses. The derivation of the luminous efficiency is ...non-trivial and is subject to biases and model assumptions. This has led to greatly varying results in the last decades of studies.
Aims.
The present paper aims to investigate how a reduction in various observational biases can be achieved to derive (more) reliable values for the luminous efficiency.
Methods.
A total of 281 meteors observed by the Fireball Recovery and InterPlanetary Observation Network (FRIPON) are studied. The luminous efficiencies of the events are computed using an ablation-based model. The relations of
τ
as a function of the pre-atmospheric meteoroid velocity,
v
e
, and mass,
M
e
, are studied. Various aspects that could render the method less valid, cause inaccuracies, or bias the results are investigated. On this basis, the best suitable meteors were selected for luminous efficiency computations.
Results.
The presented analysis shows the limits of the used method. The most influential characteristics that are necessary for reliable results for the
τ
computation were identified. We study the dependence of
τ
on the assumed meteoroid’s density,
ρ
, and include improved
ρ
-values for objects with identified meteoroid stream association. Based on the discovered individual biases and constraints we create a pre-debiased subset of 54 well-recorded events with a relative velocity change >80%, a final height <70 km, and a Knudsen number Kn < 0.01; this last value indicates that the events were observed in the continuum-flow regime. We find
τ
-values in the range between 0.012% and 1.1% for this pre-debiased subset and relations of
τ
to
v
e
and
M
e
of:
τ
=7.33⋅
v
e
−1.10
and
τ
=0.28⋅
M
e
−0.33
.
Conclusions.
The derived luminous efficiency of meteoroids depends on the assumed material density. Our results indicate that the applied debiasing method improves the analysis of
τ
from decelerated meteoroids. The underlying method is only valid for meteors in the continuum-flow regime. These events tend to have low end heights, large masses, and high deceleration.
Background. The type III secretion system (TTSS) is a major virulence determinant of Pseudomonas aeruginosa. The objective of this study was to determine whether the TTSS genotype is a useful ...prognostic marker of P. aeruginosa bacteremia mortality. We also studied the potential association between TTSS genotypes and multidrug-resistant (MDR) profiles, and how this interaction impacts the outcome of bloodstream infections. Methods. We performed a post hoc analysis of a published prospective multicenter cohort of P. aeruginosa bloodstream infections. The impact in mortality of TTSS genotypes (exoS, exoT, exoU, and exoY genes) and resistance profiles was investigated. Cox regression analysis was used to control for confounding variables. Results. Among 590 patients, the 30-day mortality rate was 30% (175 patients), and 53% of them died in the first 5 days (early mortality). The unadjusted probabilities of survival until 5 days was 31.4% (95% confidence interval CI, 17.4%–49.4%) for the patients with exoU-positive isolates and 53.2% (95% CI, 44.6%–61.5%) for exoU-negative isolates (log rank P = .005). After adjustment for confounders, exoU genotype (adjusted hazard ratio aHR, 1.90 95% CI, 1.15–3.14; P = .01) showed association with early mortality. In contrast, late (30-day) mortality was not influenced by TTSS genotype but was independently associated with MDR profiles (aHR, 1.40 95% CI, 1.01–1.94; P = .04). Moreover, the exoU genotype (21% of all isolates) was significantly less frequent (13%) among MDR strains (particularly among extensively drug-resistant isolates, 5%), but was positively linked to moderately resistant (1–2 antipseudomonals) phenotypes (34%). Conclusions. Our results indicate that the exoU genotype, which is associated with specific susceptibility profiles, is a relevant independent marker of early mortality in P. aeruginosa bacteremia.
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