Explore the vast range of titles available.

This paper introduces an innovative improvement to impressed current cathodic protection (ICCP) systems by integrating a pulse-feeding technique designed to address metal protection degradation during off-potential periods, a common issue in conventional systems. The proposed system enhances the overall effectiveness and reliability of ICCP, providing consistent corrosion protection for critical metal structures. A notable advantage of this method is its simplicity, utilizing a cost-effective microcontroller for pulse feeding. This approach simplifies integration processes and enhances cost-effectiveness, making it an attractive solution for improving cathodic protection system performance without substantial additional costs. The method addresses conventional ICCP weaknesses by applying a high-frequency pulse current during off-potential periods. This reduces excessive negative charge buildup on metal surfaces during interruptions, boosting the system’s effectiveness and stability. Research laboratory experiments were conducted using pulse width modulation (PWM) on an ATmega328P microcontroller to demonstrate the method’s effectiveness. Additionally, an IoT-monitored ICCP system was developed using an ESP32 microcontroller and the Blynk application. Results highlight the superiority of a 50 kHz pulse feeding frequency in preventing corrosion compared to lower frequencies. Overall, this advancement significantly enhances ICCP systems, providing improved corrosion protection and durability in harsh environments.

This work aimed to evaluate the effects of dietary supplementation with β-glucans extracted from yeast (Saccharomyces cerevisiae) and microalga (Phaeodactylum tricornutum) on gene expression, oxidative stress biomarkers and plasma immune parameters in gilthead seabream (Sparus aurata) juveniles. A practical commercial diet was used as the control (CTRL), and three others based on CTRL were further supplemented with different β-glucan extracts. One was derived from S. cerevisiae (diet MG) and two different extracts of 21% and 37% P. tricornutum-derived β-glucans (defined as Phaeo21 and Phaeo37), to give a final 0.06% β-glucan dietary concentration. Quadruplicate groups of 95 gilthead seabream (initial body weight: 4.1 ± 0.1 g) were fed to satiation three times a day for 8 weeks in a pulse-feeding regimen, with experimental diets intercalated with the CTRL dietary treatment every 2 weeks. After 8 weeks of feeding, all groups showed equal growth performance and no changes were found in plasma innate immune status. Nonetheless, fish groups fed β-glucans supplemented diets showed an improved anti-oxidant status compared to those fed CTRL at both sampling points (i.e., 2 and 8 weeks). The intestinal gene expression analysis highlighted the immunomodulatory role of Phaeo37 diet after 8 weeks, inducing an immune tolerance effect in gilthead seabream intestine, and a general down-regulation of immune-related gene expression. In conclusion, the results suggest that the dietary pulse administration of a P. tricornutum 37% enriched-β-glucans extract might be used as a counter-measure in a context of gut inflammation, due to its immune-tolerant and anti-oxidative effects.

Recently, the use of click chemistry for localization of chemically modified cyanopeptides has been introduced, i.e., taking advantage of promiscuous adenylation (A) domains in non-ribosomal peptide synthesis (NRPS), allowing for the incorporation of clickable non-natural amino acids (non-AAs) into their peptide products. In this study, time-lapse experiments have been performed using pulsed feeding of three different non-AAs in order to observe the synthesis or decline of azide- or alkyne-modified microcystins (MCs) or anabaenopeptins (APs). The cyanobacteria Microcystis aeruginosa and Planktothrix agardhii were grown under maximum growth rate conditions (r = 0.35–0.6 and 0.2–0.4 (day−1), respectively) in the presence of non-AAs for 12–168 h. The decline of the azide- or alkyne-modified MC or AP was observed via pulse-feeding. In general, the increase in clickable MC/AP in peptide content reached a plateau after 24–48 h and was related to growth rate, i.e., faster-growing cells also produced more clickable MC/AP. Overall, the proportion of clickable MC/AP in the intracellular fraction correlated with the proportion observed in the dissolved fraction. Conversely, the overall linear decrease in clickable MC/AP points to a rather constant decline via dilution by growth instead of a regulated or induced release in the course of the synthesis process.

The growing consumer demand for natural products led to an increasing interest in vanillin production by biotechnological routes. In this work, the biotechnological vanillin production by Amycolatopsis sp. ATCC 39116 is studied using ferulic acid as precursor, aiming to achieve maximized vanillin productivities. During biotech-vanillin production, the effects of glucose, vanillin and ferulic acid concentrations in the broth proved to be relevant for vanillin productivity. Concerning glucose, its presence in the broth during the production phase avoids vanillin conversion to vanillic acid and, consequently, increases vanillin production. To avoid the accumulation of vanillin up to a toxic concentration level, a multiple-pulse-feeding strategy is implemented, with intercalated vanillin removal from the broth and biomass recovery. This strategy turned out fruitful, leading to 0.46 g L−1 h−1 volumetric productivity of vanillin of and a production yield of 0.69 gvanillin gferulicacid−1, which are among the highest values reported in the literature for non-modified bacteria.

In non-ribosomal peptide synthesis of cyanobacteria, promiscuous adenylation domains allow the incorporation of clickable non-natural amino acids into peptide products—namely into microcystins (MCs) or into anabaenopeptins (APs): 4-azidophenylalanine (Phe-Az), N-propargyloxy-carbonyl-L-lysine (Prop-Lys), or O-propargyl-L-tyrosine (Prop-Tyr). Subsequently, chemo-selective labeling is used to visualize the clickable cyanopeptides using Alexa Fluor 488 (A488). In this study, the time-lapse build up or decline of azide- or alkyne-modified MCs or APs was visualized during maximum growth, specifically MC biosynthesis in Microcystis aeruginosa and AP biosynthesis in Planktothrix agardhii. Throughout the time-lapse build up or decline, the A488 signal occurred with heterogeneous intracellular distribution. There was a fast increase or decrease in the A488 signal for either Prop-Tyr or Prop-Lys, while a delayed or unobservable A488 signal for Phe-Az was related to increased cell size as well as a reduction in growth and autofluorescence. The proportion of clickable MC/AP in peptide extracts as recorded by a chemical–analytical technique correlated positively with A488 labeling intensity quantified via laser-scanning confocal microscopy for individual cells or via flow cytometry at the population level. It is concluded that chemical modification of MC/AP can be used to track intracellular dynamics in biosynthesis using both analytical chemistry and high-resolution imaging.

Pulse feeding and growth of the Black Sea strain of dinoflagellates Oxyrrhis marina (Dujardin, 1841) (OXY–IBSS), equivalent spherical diameter (ESD) (23.5 ± 3.1 μm) have been studied under experimental conditions simulating phytoplankton blooms. Microalgae Phaeodactylum tricornutum ( P , ESD 3.4 ± 0.3 μm), Isochrysis galbana ( I, ESD 3.7 ± 0.4 μm), Tetraselmis suecica ( T, ESD 6.1 ± 0.9 μm), and Rhodomonas salina (R, 7.4 ± 0.7 µm) were used as food objects in a one-component and three-component suspensions. Microalgae concentrations (∼10 6 cells/mL for T and R ; up to ∼4 × 10 6 cells/mL for P and I ) were chosen to ensure their equal total carbon biomass ∼0.02 μg C/μL in the food mixtures at the beginning of the experiment . Under ad libitum conditions, the maximum clearance rates of the OXY–IBSS reached 0.1–0.5 μL ind./day, and the grazing rate of microalgae was 34–44 cells/(ind h) for P and I, and 2–11 cells/(ind. h) for R and T, respectively. The grazing rate of microalgae in carbon units was significantly higher when feeding on I (3.9 ng C/(ind. day)) and significantly less when fed with a mixture of microalgae TRP (1.5 ng C/(ind. day)). Maximum abundance of OXY–IBSS, achieved within 3 or 4 days (by the time the microalgae concentration decreased below threshold), varied from 19 × 10 3 ind./mL ( P ) to 43 × 10 3 ind./mL ( I ). In the absence of food, dinoflagellates O. marina turned to cannibalism, and within 4 days the oscillating fluctuations (within 50%) in their number took place. Although the specific population growth rate (μ, day -1 ) of OXY–IBSS was higher when feeding on small cells (∼2 days –1 on I ), the gross growth efficiency (GGE) of OXY–IBSS was significantly higher when fed on large ( T and R ) microalgae (26–29% vs. 14–15%). At lower daily rations (DRs) when fed with the mixture TRP, the GGE of OXY–IBSS was significantly higher (41%) when compared to other nutritional conditions. The feeding strategy of opportunistic predator O. marina on diverse (in terms of size and chemotaxonomic characteristics) mixtures of prey lay in a flexible choice between high specific population growth rate, or high gross growth efficiency, that obviously gives the populations of this species the advantages over other protists under conditions of the pulsed phytoplankton blooms.

Aging is associated with a blunted anabolic response to dietary intake, possibly related to a decrease in systemically available amino acids (AAs), which in turn may stem from increased splanchnic AA metabolism. Splanchnic sequestration can be saturated by pulse feeding (80% of daily protein intake in a single meal), enabling increased protein synthesis. The aim of this study was to explore whether protein pulse feeding increased postprandial AA concentrations, and if so whether this increase persisted after 6 wk of dietary treatment. This prospective randomized study enrolled 66 elderly malnourished or at-risk patients in an inpatient rehabilitation unit. All were given a controlled diet for 6 wk. In a spread diet (SD) group (n = 36), dietary protein was spread over the four daily meals. In a pulse diet (PD) group (n = 30), 72% of dietary protein (averaging 1.31 g/kg body weight daily) was consumed in one meal at noon. The patients were evaluated on day 1 and at 6 wk for plasma postprandial (five times from 0 to +180 min) AA concentrations (expressed as area under the curve above baseline). Protein pulse feeding was more efficient than protein spread feeding at increasing plasma postprandial AA concentrations, notably of essential AAs. This increased postprandial AA bioavailability was maintained after 6 wk. This study demonstrates that increased postprandial AA bioavailability induced by protein pulse feeding persists after 6 wk (i.e., that there is no metabolic adaptation blunting AA bioavailability).

Nowadays, much attention is being paid to environmental issues since legislation has become stricter. Membrane bioreactors (MBR) are non-conventional treatment systems that gain ground in wastewater processing. In this study, the operation of a 24 L submerged membrane bioreactor, treating municipal wastewater, was investigated under different organic loading rates and high mixed liquor suspended solids concentrations (up to 13 g/L). The system, consisting of a hollow fibre membrane for ultrafiltration (0.1 μm pore-size), was operated under intermittent aeration (30 min/30 min aeration - on & off) and periodic feeding at the beginning of the anoxic phase, while effluent was discarded at the end of the aerobic phase. The transmembrane pressure and operation processes were monitored and controlled by a programmable logic controller (PLC). Complete suspended solids removal was achieved throughout the entire operation and BOD and COD average removal values higher than 97 % and 93 % were determined. Moreover, TKN and NH 4 + -N mean removal efficiencies were estimated to be higher than 77 % and 91 %, respectively, regardless of the increase in the organic loading rate and biomass concentration. No membrane fouling was observed since the submerged membrane bioreactor was operated below the critical flux. A 2nd order equation considering fouling and sieving phenomena was found to mathematically express critical flux. It is concluded that the MBR system could effectively operate without membrane fouling for a long period of time, even at high volumetric organic loading rates and high biosolids concentrations.