► The tetracyclines (TCs) toxicity decreased only with longer ozonation time. ► The TCs ozonation rate is increased by adding activated carbon. ► The combined system O
3-biological activated sludge ...is highly effective to mineralize TCs.
The main objective of this study was to analyze the effectiveness of ozone and of technologies based on the simultaneous use of ozone–hydrogen peroxide, ozone-activated carbon, and ozone-biological treatment in the removal of tetracyclines (TCs) from waters. The results obtained shown, regardless of the TC under study, TC degradation was complete after 10
min of ozonation. A slight decrease in total organic carbon (TOC) and medium toxicity was observed with longer TC ozonation treatment time. The presence of H
2O
2 during TC ozonation considerably increases the TC removal rate. Moreover, the O
3/H
2O
2 system had adequate oxidizing capacity to mineralize a high fraction of the total organic carbon. The presence of activated carbon during ozonation increases the TC removal rate and also produces a slight decrease in the concentration of TOC and a reduction in the medium toxicity; these effects are explained by: (i) the capacity of the carbon to adsorb TC degradation compounds, which have a smaller molecular size than the original TCs and, especially, (ii) its capacity to transform dissolved ozone into HO. The combined ozone-biological activated sludge system demonstrated a high effectiveness to degrade TCs and mineralize their degradation compounds. These are metabolized by the microorganisms in biological sludge, markedly reducing the TOC, chemical oxygen demand (COD), and biological oxygen demand (BOD); the longer the TC ozonation time before the biological treatment, the greater are these reductions.
Verification and validation are a fundamental step in the development process of computer codes, particularly when seeking to numerically evaluate physical phenomena. Multiple methodologies can be ...applied, one of which is the use of benchmark solutions. The field of inverse problems is no exception, for not only the forward problem must be verified and validated, but also the inversion technique (such as minimization methods, Bayesian inference, and level-set methods). To address the latter, this work outlines an online database of benchmark inverse problems, for the purposes of verifying computer codes for inverse problems. This online database provides test problems with suggested values for the exact parameters and regularization parameters, as well as synthetic data and their respective estimated values. Both parameter and function estimation problems are available. This database will be continuously updated over time, with new problems and/or solutions via different techniques. Users are also free to contribute with problems/solutions of their own. This data being freely and easily accessible online will be of great value for young and upcoming researchers in the field of inverse problems. The database can be accessed at
http://inversetoolkit.uff.br/
.
► The first-order kinetic fits tetracycline (TC) adsorption on sludge adsorbents. ► The rate constants vary in a linear manner with their macro-and mesopore volumes. ► The TC adsorption rate on all ...adsorbents is controlled by intraparticle diffusion. ► Pore volume diffusion represents more than 80% of the total intraparticle diffusion. ► Diffusion of TC in the pore volume increases with larger meso and macropore volume.
This study investigated the global adsorption rate of tetracycline on adsorbents obtained from treatment sludge. Experimental data on tetracycline concentration decay curves were interpreted with kinetic models (first-order, second-order, Langmuir, and intraparticle diffusion) and diffusional models (pore volume diffusion model and surface diffusion model). The first-order kinetic model provided the best interpretation of tetracycline adsorption kinetics on all adsorbents, and its rate constant varied in a linear manner the macro- and mesopore volume of the adsorbents. It was also found that the tetracycline adsorption rate is controlled by intraparticle diffusion and that diffusion in the pore volume represents >80% of total intraparticle diffusion. This indicates that surface diffusion does not play a major role in tetracycline diffusion on the different adsorbents. Furthermore, the effective tetracycline diffusion coefficient in the pore volume gradually increased with greater meso- and macropore volume and larger surface area of the adsorbent, indicating that the tetracycline adsorption rate is directly related to the accessibility of this molecule to the microporous structure of the materials.
Periodontitis is characterized by the progressive destruction of tooth-supporting alveolar bone, which is mainly caused by chronic inflammation in response to persistent bacterial insult. It has ...recently become clear that the pathogenesis of periodontitis is associated with a high ratio of proinflammatory M1 (classically activated) macrophages to anti-inflammatory M2 (alternatively activated). To decrease the inflammatory activity, we locally delivered the C-C motif chemokine ligand 2 (CCL2) using controlled-release microparticles (MPs). CCL2 is known to promote chemotaxis of M0 or M2 phenotype macrophages to the inflamed site and induce M2 phenotype polarization locally. Our in vitro data showed that CCL2 increased the number of M2 phenotype macrophages, decreased TNF-α secretion, and enhanced chemotaxis of RAW264.7 cells toward CCL2 MPs. Moreover, we induced periodontal disease in 2 animal models through inoculation of Porphyromonas gingivalis and ligature around the murine molar. Micro–computed tomography analysis showed significant reduction of alveolar bone loss in the CCL2 MP treatment group when compared with a blank MP group and a no-treatment periodontitis group in both models. Immunohistologic analysis showed a significant increase in the M2 phenotype subset and a decrease in the M1 phenotype subset in the CCL2 MP group of the P. gingivalis–induced model. Also, in both models, tartrate-resistant acidic phosphatase staining showed significantly fewer numbers of osteoclasts in the CCL2 MP group in alveolar bone area. Moreover, quantitative polymerase chain reaction results showed a significant increase in IL-1RA (interleukin 1 receptor antagonist) mRNA expression and a decrease in RANKL (receptor activator of nuclear factor kappa-Β ligand) mRNA expression in the CCL2 MP group in the ligature model. In summary, manipulation of endogenous M2 phenotype macrophages with CCL2 MPs decreased the M1 phenotype:M2 phenotype ratio and prevented alveolar bone loss in mouse periodontitis models. The delivery of CCL2 MPs provides a novel approach to treat periodontal disease.
► UV radiation is effective for the photooxidation of TCs in aqueous phase. ► The rate constants obtained indicate that the photodegradation is pH-dependent. ► The presence of H2O2 in the medium ...substantially increased the TC degradation rate. ► The TC photooxidation rate was higher in natural waters. ► The medium toxicity increased at the beginning of TC photooxidation process.
The objective of this study was to analyze the effectiveness of medium-pressure lamps in the direct and indirect photodegradation of tetracyclines (TCs). We conducted a kinetic study of the process, determining the quantum yield for three tetracyclines (tetracycline, chlorotetracycline and oxytetracycline). We also analyzed the influence of different operational variables, such as: initial concentration; solution pH; presence of natural organic matter (NOM); the chemical composition of water, using ultrapure water (UW), surface water (SW), groundwater (GW), and wastewater (WW); the behavior of total organic carbon (TOC) concentration, and the system toxicity during TCs photodegradation. The results obtained shown that medium-pressure mercury lamp radiation is effective for the photooxidation of TCs in aqueous phase, mainly when these are at low concentrations. The rate constants obtained indicate that the photodegradation is pH-dependent and favored at pH 10 regardless of the tetracycline considered. The presence of H2O2 in the medium substantially increased the TC degradation rate and considerably reduced the time required to degrade 100% of the initial TC concentration. The TC photooxidation rate was higher in natural waters than in ultrapure water, attributable to the presence of dissolved organic matter, which can act as a photosensitizer, thereby favoring indirect TC degradation through the formation of radical species such as HO•. TOC values at the end of the treatment indicated that the percentage mineralization is a function of the initial TC concentration. The medium toxicity increased at the beginning of TC photooxidation, and treatment times of around 60min are generally required for the toxicity to be lower than in the original solution.
The appropriate choice of reference genes is essential for accurate normalization of gene expression data obtained by the method of reverse transcription quantitative real-time PCR (RT-qPCR). In ...2009, a guideline called the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) highlighted the importance of the selection and validation of more than one suitable reference gene for obtaining reliable RT-qPCR results. Herein, we searched the recent literature in order to identify the bacterial reference genes that have been most commonly validated in gene expression studies by RT-qPCR (in the first 5 years following publication of the MIQE guidelines). Through a combination of different search parameters with the text mining tool MedlineRanker, we identified 145 unique bacterial genes that were recently tested as candidate reference genes. Of these, 45 genes were experimentally validated and, in most of the cases, their expression stabilities were verified using the software tools geNorm and NormFinder. It is noteworthy that only 10 of these reference genes had been validated in two or more of the studies evaluated. An enrichment analysis using Gene Ontology classifications demonstrated that genes belonging to the functional categories of DNA Replication (GO: 0006260) and Transcription (GO: 0006351) rendered a proportionally higher number of validated reference genes. Three genes in the former functional class were also among the top five most stable genes identified through an analysis of gene expression data obtained from the Pathosystems Resource Integration Center. These results may provide a guideline for the initial selection of candidate reference genes for RT-qPCR studies in several different bacterial species.
Anthracnose (ANT) and angular leaf spot (ALS) are devastating diseases of common bean (Phaseolus vulgaris L.). Ouro Negro is a highly productive common bean cultivar, which contains the Co-10 and ...Phg-ON genes for resistance to ANT and ALS, respectively. In this study, we performed a genetic co-segregation analysis of resistance to ANT and ALS using an F₂ population from the Rudá × Ouro Negro cross and the F₂:₃ families from the AND 277 × Ouro Negro cross. Ouro Negro is resistant to races 7 and 73 of the ANT and race 63-39 of the ALS pathogens. Conversely, cultivars AND 277 and Rudá are susceptible to races 7 and 73 of ANT, respectively. Both cultivars are susceptible to race 63-39 of ALS. Co-segregation analysis revealed that Co-10 and Phg-ON were inherited together, conferring resistance to races 7 and 73 of ANT and race 63-39 of ALS. The Co-10 and Phg-ON genes were co-segregated and were tightly linked at a distance of 0.0 cM on chromosome Pv04. The molecular marker g2303 was linked to Co-10 and Phg-ON at a distance of 0.0 cM. Because of their physical linkage in a cis configuration, the Co-10 and Phg-ON resistance alleles are inherited together and can be monitored with great efficiency using g2303. The close linkage between the Co-10 and Phg-ON genes and prior evidence are consistent with the existence of a resistance gene cluster at one end of chromosome Pv04, which also contains the Co-3 locus and ANT resistance quantitative trait loci. These results will be very useful for breeding programs aimed at developing bean cultivars with ANT and ALS resistance using marker-assisted selection.
In polymer membrane fuel cells (PEMFC), the pore microstructure and the effective diffusion coefficient (
) of the catalytic layer have a significant impact on the overall performance of the fuel ...cell. In this work, numerical methods to simulate PEMFC catalytic layers were used to study the effect of isotropy (
) on the
. The proposed methodology studies reconstructed systems by Simulated Annealing imaging with different surface fractions of microstructures composed by two diffusive phases: agglomerates and pores. The
is determined numerically by the Finite Volume Method solved for Fick's First Law of Diffusion. The results show that the proposed methodology can effectively quantify the effect of isotropy on the
for both diffusion phases. Two trends were obtained in the magnitude of the
concerning the change in isotropy: (1) an analytical equation is proposed in this article for
and (2) numerical solutions are determined for
In our analytical equation are both a lineal and a logarithmic sweep. When the surface fraction is
50%, the
decreases more linearly than
at the beginning of the isotropy change, which indicates that small changes in isotropy in the particulate material modify it drastically; under these conditions the diffusion coefficient in the pore is predominant. (3) When the surface fraction is less than 50%, the
decreases more exponentially at the beginning and more linearly at the end of the isotropy change, which shows that small isotropy changes in the bar-aligned material drastically alter it. In this trend, diffusion in the agglomerate is less affected by isotropy. The proposed methodology can be used as a design tool to improve the mass transport in porous PEMFC electrodes.
Current tobacco treatment guidelines have established the efficacy of available interventions, but they do not provide detailed guidance for common implementation questions frequently faced in the ...clinic. An evidence-based guideline was created that addresses several pharmacotherapy-initiation questions that routinely confront treatment teams.
Individuals with diverse expertise related to smoking cessation were empaneled to prioritize questions and outcomes important to clinicians. An evidence-synthesis team conducted systematic reviews, which informed recommendations to answer the questions. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach was used to rate the certainty in the estimated effects and the strength of recommendations.
The guideline panel formulated five strong recommendations and two conditional recommendations regarding pharmacotherapy choices. Strong recommendations include using varenicline rather than a nicotine patch, using varenicline rather than bupropion, using varenicline rather than a nicotine patch in adults with a comorbid psychiatric condition, initiating varenicline in adults even if they are unready to quit, and using controller therapy for an extended treatment duration greater than 12 weeks. Conditional recommendations include combining a nicotine patch with varenicline rather than using varenicline alone and using varenicline rather than electronic cigarettes.
Seven recommendations are provided, which represent simple practice changes that are likely to increase the effectiveness of tobacco-dependence pharmacotherapy.
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