•How temperature and KOH concentration influence on the carotenoids extraction.•How different polarity solvents influence on the recovery.•To establish a standard method for all microalgae is not ...possible.
Microalgae are an interesting source of natural pigments that have valuable applications. However, further research is necessary to develop processes that allow us to achieve high levels of carotenoid recovery while avoiding degradation. This work presents a comprehensive study on the recovery of carotenoids from several microalgae genera, optimizing carotenoid extraction using alkaline saponification at various temperatures and KOH concentrations. Results show that I. galbana requires a temperature of 60 °C and <10% KOH, N. gaditana and K. veneficum require 60 °C and no saponification, P. reticulatum requires 40 °C and 10% KOH, T. suecica and H. pluvialis require 25 °C and 40% KOH while C. sp. and S. almeriensis require 80 °C and 40% KOH. The influence of the solvent on carotenoid recovery was also studied. In general terms, an ethanol:hexane:water (77:17:6 v/v/v) mixture results in good yields.
Interbedded contourites, turbidites and pelagites are commonplace in many deep‐water slope environments. However, the distinction between these different facies remains a source of controversy. This ...detailed study of calcareous contourites and associated deep‐marine facies from an Eocene–Miocene sedimentary succession on Cyprus clearly documents the diagnostic value of microfacies in this debate. In particular, the variability of archetypical bi‐gradational contourite sequences and their internal subdivision (bedding, layering and lamination) are explored. Contourites can be distinguished from turbidites, pelagites and hemipelagites by means of carbonate microfacies in combination with bed‐scale characteristics. Particle composition provides valuable information on sediment provenance. Depositional texture, determined by the ratio between carbonate mud and bioclasts, is crucial for identifying bi‐gradational sequences in both muddy and sandy contourites, and normally‐graded sequences in turbidite beds. Equally important are the type and preservation of traction structures, as well as the temporality and impact of bioturbation. Shell fragmentation under conditions of increased hydrodynamic agitation (textural inversion) is recognized as a carbonate‐specific feature of bioclastic sandy contourites.
Summary
Background
Empiric triple therapy for Helicobacter pylori should be abandoned when clarithromycin resistance rate is >15–20%. Optimisation of triple therapy (high‐dose acid suppression and ...14‐day duration) can increase eradication rates by 10%.
Aim
To compare the efficacy and safety of optimised triple (OPT‐TRI) and nonbismuth quadruple concomitant (OPT‐CON) therapies.
Methods
Prospective multicentre study in 16 Spanish centres using triple therapy in clinical practice. In a 3‐month two‐phase fashion, the first 402 patients received an OPT‐TRI therapy esomeprazole (40 mg b.d.), amoxicillin (1 g b.d) and clarithromycin (500 mg b.d) for 14 days and the last 375 patients an OPT‐CON treatment OPT‐TRI therapy plus metronidazole (500 mg b.d).
Results
Seven‐hundred seventy‐seven consecutive patients were included (402 OPT‐TRI, 375 OPT‐CON). The OPT‐CON therapy achieved significantly higher eradication rates in the per‐protocol 82.3% (95% CI = 78–86%) vs. 93.8% (91–96%), P < 0.001 and intention‐to‐treat analysis 81.3% (78–86%) vs. 90.4% (87–93%), P < 0.001. Adverse events (97% mild/moderate) were significantly more common with OPT‐CON therapy (39% vs. 47%, P = 0.016), but full compliance with therapy was similar between groups (94% vs. 92%, P = 0.4). OPT‐CON therapy was the only significant predictor of successful eradication (odds ratio, 2.24; 95% CI: 1.48–3.51, P < 0.001). The rate of participating centres achieving cure rates ≥90% favoured OPT‐CON therapy (OPT‐TRI 25% vs. OPT‐CON 62%).
Conclusions
Empiric OPT‐CON therapy achieved significantly higher cure rates (>90%) compared to OPT‐TRI therapy. Addition of metronidazole to OPT‐TRI therapy increased eradication rates by 10%, resulting in more mild adverse effects, but without impairing compliance with therapy.
This work deals with the evolution of intermediates and ecotoxicity upon Fenton's oxidation of phenol in aqueous solution. The EC50 values of the intermediates identified in the oxidation pathway of ...phenol have been measured. Some of these compounds, mainly hydroquinone and p-benzoquinone, showed toxicity levels much higher than phenol itself. Depending on the operating conditions, these intermediates could be completely transformed into organic acids, mainly oxalic and formic. Ecotoxicity values substantially lower than those expected from the chemical composition were measured in the reaction samples. This is explained by a reduction of the concentration of aromatic intermediates when the pH was adjusted at 6−8 (according to what is required by the standard bioassay ISO 11348-3). Formation of complexes between hydroquinone and p-benzoquinone at increasing pH can remove from solution those highly toxic intermediates whose very low EC50 values give rise to a high ecotoxicity even at fairly low concentrations. This together with the enhanced decomposition of residual H2O2 at increasing pH represent important beneficial effects of the neutralization step following Fenton treatment which allow a complementary cleaning of the effluent.
This review aims to assess different technologies for the on-site treatment of hospital wastewater (HWW) to remove pharmaceutical compounds (PhCs) as sustances of emerging concern at a bench, pilot, ...and full scales from 2014 to 2020. Moreover, a rough characterisation of hospital effluents is presented. The main detected PhCs are antibiotics and psychiatric drugs, with concentrations up to 1.1 mg/L. On the one hand, regarding the presented technologies, membrane bioreactors (MBRs) are a good alternative for treating HWW with PhCs removal values higher than 80% in removing analgesics, anti-inflammatories, cardiovascular drugs, and some antibiotics. Moreover, this system has been scaled up to the pilot plant scale. However, some target compounds are still present in the treated effluent, such as psychiatric and contrast media drugs and recalcitrant antibiotics (erythromycin and sulfamethoxazole). On the other hand, ozonation effectively removes antibiotics found in the HWW (>93%), and some studies are carried out at the pilot plant scale. Even though, some families, such as the X-ray contrast media, are recalcitrant to ozone. Other advanced oxidation processes (AOPs), such as Fenton-like or UV treatments, seem very effective for removing pharmaceuticals, Antibiotic Resistance Bacteria (ARBs) and Antibiotic Resistance Genes (ARGs). However, they are not implanted at pilot plant or full scale as they usually consider extra reactants such as ozone, iron, or UV-light, making the scale-up of the processes a challenging task to treat high-loading wastewater. Thus, several examples of biological wastewater treatment methods combined with AOPs have been proposed as the better strategy to treat HWW with high removal of PhCs (generally over 98%) and ARGs/ARBs (below the detection limit) and lower spending on reactants. However, it still requires further development and optimisation of the integrated processes.
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•This review focuses on 2014 to 2020 papers related to hospital effluents treatments.•Membrane bioreactors remove pharmaceuticals (>80%) at pilot plant scale.•Advanced Oxidation processes require further development at high scales.•Combined technologies also remove antibiotic resistance bacteria and genes.•Advanced oxidation processes are promising alternatives to treat hospital effluents.
Aliment Pharmacol Ther 31, 1077–1084
Summary
Background Helicobacter pylori eradication rates with standard triple therapy have declined to unacceptable levels.
Aim To compare clarithromycin and ...levofloxacin in triple and sequential first‐line regimens.
Methods A total of 460 patients were randomized into four 10‐day therapeutic schemes (115 patients per group): (i) standard OCA, omeprazole, clarithromycin and amoxicillin; (ii) triple OLA, omeprazole, levofloxacin and amoxicillin; (iii) sequential OACM, omeprazole plus amoxicillin for 5 days, followed by omeprazole plus clarithromycin plus metronidazole for 5 days; and (iv) modified sequential OALM, using levofloxacin instead of clarithromycin. Eradication was confirmed by 13C‐urea breath test. Adverse effects and compliance were assessed by a questionnaire.
Results Per protocol cure rates were: OCA (66%; 95% CI: 57–74%), OLA (82.6%; 75–89%), OACM (80.8%; 73–88%) and OALM (85.2%; 78–91%). Intention‐to‐treat cure rates were: OCA (64%; 55–73%), OLA (80.8%; 73–88%), OACM (76.5%; 69–85%) and OALM (82.5%; 75–89%). Eradication rates were lower with OCA than with all the other regimens (P < 0.05). No differences in compliance or adverse effects were demonstrated among treatments.
Conclusions Levofloxacin‐based and sequential therapy are superior to standard triple scheme as first‐line regimens in a setting with high clarithromycin resistance. However, all of these therapies still have a 20% failure rate.
Charge parity asymmetry in charmless B meson decays is a key issue to be understood. Many theoretical calculations have been performed using short distance factorization approaches which, in general, ...do not take into account the CPT invariance constraint. For each channel with CP violation there is an equal amount of CP asymmetry in another channel or other channels, with an opposite sign. This happens if these channels are coupled through final state interactions. In the specific process B→PV, involving one pseudoscalar and one vector particle in the final state, we argue that the CP asymmetry, inherent from a short distance mechanism, could be suppressed due to the CPT constraint. In this case, we propose a sensitive and practical experimental method to identify even a small CP asymmetry, which provides the values for ACP without the need for an amplitude analysis. This method, if applied directly to data, will enable one to extract the CP asymmetry information in a model independent way and check to which extent the suggested suppression due to the CPT constraint is verified.
Interplay of deep‐water sedimentary processes is responsible for building a myriad of features and deposits across mixed turbidite–contourite systems, from <5 cm beds to >200 km long sedimentary ...drifts. Investigations of the spatial and temporal variability of their sedimentary facies and facies associations is crucial to reveal the dynamics between along‐slope bottom currents and down‐slope turbidity currents, as well as their impact on drift construction and channel erosion. This study focuses on extensive modern mixed (turbidite–contourite) systems, developed across the continental rise of the Pacific margin of the Antarctic Peninsula. Nine sediment cores were sampled and analysed, through grain size and geochemical methods, to study the sedimentary facies at high‐resolution (ca 1 to 20 cm). Three main facies associations have been identified across distinct morphological features (i.e. mounded drifts and trunk channels), comprising intercalations of hemipelagites, bottom current reworked sands (which include fine to coarse‐grained contourites) and gravitational facies (turbidites and mass‐transport deposits). These facies associations reflect fluctuations of the background sedimentation, oscillations of the bottom‐current velocity and of the frequency of gravity‐driven currents. The sedimentary record features cyclic alternations during the Late Quaternary (>99 kyr), suggesting that variations between along‐slope bottom currents and down‐slope turbidity currents are strongly linked to glacial–interglacial cycles during Marine Isotope Stages 1 to 6. Sedimentary records affected by bottom currents on polar margins, such as those of the Antarctic Peninsula, are essential to decipher the facies and facies sequences of bottom‐current deposits, as the low degree of bioturbation throughout most of the sediments allows us to observe the original sedimentary structures, which are poorly preserved in similar deposits from other continental margins.
Tyrosinase is a copper enzyme with broad substrate specifity toward a lot of phenols with different biotechnological applications. The availability of quick and reliable measurement methods of the ...enzymatic activity of tyrosinase is of outstanding interest. A series of spectrophotometric methods for determining the monophenolase and diphenolase activities of tyrosinase are discussed. The product of both reactions is the o-quinone of the corresponding monophenol/diphenol. According to the stability and properties of the o-quinone, the substrate is classified as four substrate types. For each of these substrate types, we indicate the best method for measuring diphenolase activity (among eight methods) and, when applicable, for measuring monophenolase activity (among four methods). The analytical and numerical solutions to the system of differential equations corresponding to the reaction mechanism of each case confirm the underlying validity of the different spectrophotometric methods proposed for the kinetic characterization of tyrosinase in its action on different substrates.
This paper summarizes the experimental results of a series of cyclic simple shear tests on liquefiable silty sand with and without sample improvement with colloidal silica grout. The objective of the ...paper is to evaluate the effectiveness of colloidal silica grouting in reducing the liquefaction potential of natural silty sand. Colloidal silica was selected as a stabilizing material due to its low viscosity, wide range of gel times, nontoxicity, and low cost. The soil tested in this experimental program is a poorly graded sand with 11.5% of nonplastic silt from the Port of Lázaro Cárdenas, México. Colloidal silica treated and untreated sand specimens show different pore pressure response and deformation behavior under cyclic loading in simple shear tests. The results indicate that, for a given initial relative density and initial effective vertical stress, liquefiable silty sand specimens stabilized with colloidal silica grout generally exhibit significant gain in liquefaction resistance compared with untreated specimens. It was also found that the colloidal silica grout reduces considerably the rates of pore pressure generation and shear strain of the silty sand specimens subjected to cyclic loading.
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