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A two phase population balance is used to predict the polydispersed bubble flow and size distribution in a slab continuous casting mold and Submerged Entry Nozzle (SEN) system. Multiple Size Group (MUSIG) with a suitable breakage and coalescence model (Ansys CFX) was adopted to account for the polydispersed gas flow. Initial bubble size distribution as determined for two industrial refractories have been taken in consideration. A two way coupling model including the effect of the drag force and non-drag forces such as virtual mass force and turbulent dispersion force was considered. The results are compared with gas distribution in a 1:1 scale water — air mold model running under conditions of fluidynamic similarity to validate the model. The simulations have then been extended to describe the actual steel — argon flow, considering a thermal expansion factor for argon bubbles. The effect of gas distribution on the flow field of liquid inside the mold and other metallurgical aspects are discussed.

New leishmanicidal products are needed for the treatment to be effective, since current drugs are toxic to healthy human/animal cells and have low efficacy against the parasite. Bioactive compounds from microalgae, such as lectins, can be explored as new anti-Leishmania candidates. This study aimed to evaluate the cytotoxic and anti-Leishmania action of the cell extract (CE) and lectin (CVU) from Chlorella vulgaris biomass. CVU purified from CE was stable within alkaline pH and temperature below 50 °C. CVU showed specificity to the carbohydrate D-Galactose, which is found in the membrane of Leishmania. CE (IC 50  = 161.4 μg/mL) and CVU (IC 50  = 66.32 μg/mL) exhibited effects against the promastigotes of L. braziliensis, and scanning electron microscopy confirmed alterations the shape and size in treated parasites. CE showed a higher selectivity index than CVU on L. braziliensis promastigotes. These results demonstrate the potential of C. vulgaris as a source of active molecules that can be investigated as therapeutic candidates., Competing Interests: Declaration of competing interest The authors have no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

Peripheral serotonin has been shown to regulate important physiological functions such as energy homeostasis and immunity, particularly in rodent and humans, but its role is poorly understood in livestock species. Herein, we tested the safety and effectiveness of increasing serotonin bioavailability in preweaned dairy calves by oral supplementation of a serotonin precursor (5-hydroxytryptophan, 5-HTP) or a serotonin reuptake inhibitor (fluoxetine, FLX). Bull Holstein calves (21 ± 2 d old; N = 24) were fed milk replacer (8 L/d) supplemented with either saline as control (CON, 8 mL/d, n = 8), FLX (40 mg/d, approx. 0.8 mg/kg; n = 8), or 5-HTP (90 mg/d, approx. 1.8 mg/kg; n = 8) for 10 consecutive days in a complete randomized block design. Heart rate (HR), respiration rate, rectal temperature, and health scores were recorded daily. Hip height and body weight were measured at d 1, 5, and 10 relative to initiation of supplementation. Blood samples were collected once before the supplementation period (d 1), during the 10-d supplementation period (daily), and during a 14-d withdrawal period (d 2, 3, 4, 7, and 14 relative to initiation of withdrawal). Cerebrospinal fluid and muscle tissue were collected from a subset of calves (n = 12) that were euthanized after the 10-d supplementation or 14-d withdrawal period. Whole blood serotonin concentrations increased in 5-HTP calves and decreased in FLX calves compared with CON (P < 0.001), indicating that serotonin bioavailability was increased in both groups. Whole blood serotonin concentrations of 5-HTP and FLX calves returned to CON levels after 7 d of withdrawal. All calves grew and were considered healthy throughout the study. In fact, calves fed 5-HTP had higher average daily gain compared with CON (0.87 vs 0.66 ± 0.12 kg/d, P = 0.05). Calves fed FLX had lower HR (P = 0.02) and greater red blood cells and hemoglobin counts on d 10 of supplementation compared with CON (P < 0.01). After the 14-d withdrawal period, FLX was not detected in circulation of FLX calves, but was still present in the muscle tissue. Our results demonstrate that manipulation of the serotonin pathway by supplementing FLX or 5-HTP is a feasible and safe approach in preweaned dairy calves; however, it takes more than 14 d for FLX to be completely withdrawn from the body., (Copyright © 2019 Elsevier Inc. All rights reserved.)

A series of organotin(IV) derivatives was investigated in vitro for their antibiotic and adjuvant antibiotic properties (efflux pump inhibitors) against Staphylococcus aureus strains that overexpress efflux pump proteins for norfloxacin (SA-1199B), erythromycin (RN-4220) and tetracycline (IS-58). Most organotin(IV) compounds showed significant antibacterial activity with small Minimum Inhibitory Concentration (MIC) values, some of which were close to 1.0μg/mL (3.1μM), but this feature was also associated with substantial cytotoxicity. Nevertheless, the cytotoxicity of these organotin(IV) compounds can be overcome when they are used as antibiotic adjuvants. Their remarkable adjuvant antibiotic properties allow potentiation of the action of tetracycline (against IS-58 strain) by up to 128-fold. This likely indicates that they can act as putative inhibitors of bacterial efflux pumps. These results reinforce organotin(IV) complexes as promising antibacterial agents, and many of these complexes, if associated with antibiotics, can act as potential adjuvant antibiotic candidates., (Copyright © 2017 Elsevier Inc. All rights reserved.)

This paper describes a method development for chlorine determination through the formation of MgCl molecule, applied for the first time for Cl quantification, by high resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) in environmental samples. Pyrolysis and vaporization temperatures were optimized as well as the use of chemical modifier. Determinations were carried out at the wavelength of 377.010 and the compromise conditions of the graphite furnace temperature program were 500°C and 2500°C for pyrolysis and vaporization, respectively, using 10µg of chemical modifier Pd. The concentration of reactants for the generation of MgCl molecule was optimized through Box-Behnken experimental design, using MgCl 2 solution as source of chlorine. The optimum values according to the surface response were 5gL -1 Mg, 25mgL -1 of chlorine and 2% vv -1 of HNO 3 , condition in which the amount of Mg is at least 200 times higher than that of chloride. This excess of the forming agent ensures the complete formation of MgCl molecular species, since Cl is the limiting reactant. Certified reference materials, BCR 182 and NIST 8414, and addition and recovery tests were used to evaluate the accuracy of the method and good results were achieved at a 95% confidence level. The method was applied to direct determination of Cl in five produced water samples from offshore oil wellbore, high complex matrix, whose conventional methods require tedious treatment before the analysis., (Copyright © 2017. Published by Elsevier B.V.)

Water recycling and industrial effluents remediation are a hot topic of research to reduce the environmental impact of the human activity. Persistent organic pollutants are highly recalcitrant compounds with hazardous effects associated to their fate in water bodies. Several novel technologies have been developed during the last decades to deal with this novel contamination. However, the natural sources and idiosyncrasy of each country lead to the potential application of different technologies. In this context, we have focused on the development of phocotalytic treatment of solutions containing dyes using a novel photocatalytic material, the NbO 2 OH. The NbO 2 OH was synthesized and characterized with different techniques. Several assays demonstrated the solar photoactivity of this novel oxyhydroxide catalyst, achieving complete decolorizations after 10min of treatment under optimal conditions of 1.0gL -1 NbO 2 OH photocatalyst loading, 0.1M of H 2 O 2 as electron scavenger, pH4.0 and methyl orange concentrations up to 15mgL -1 . Also, the catalyst recuperation demonstrated the potential reuse of this photocatalyst without losing catalytic response after five cycles. This work is of significant importance because niobium is a natural resource, mainly extracted in Brazil and the annual global sunlight irradiation in the near-equatorial region of northeast Brazil is over the average solar irradiation of the planet. Thus, the solar photocatalytic treatment using NbO 2 OH in northeast Brazil appears as a highly potential environmental-friendly nanotechnology to mitigate the water pollution., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Global warming will certainly affect the abundance and distribution of disease vectors. The effect of global warming, however, depends on the complex interaction between the human host population and the causative infectious agent. In this work we review some mathematical models that were proposed to study the impact of the increase in ambient temperature on the spread and gravity of some insect-transmitted diseases., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Chitosan is a polysaccharide used in a broad range of applications. Many of its unique properties come from the presence of amino groups in its structure. A proper quantification of these amino groups is very important, in order to specify if a given chitosan sample can be used in a particular application. In this work, a comparison between the determination of chitosan degree of deacetylation by conductometry and CHN elemental analysis was carried out, using a rigorous error analysis. Accurate expressions relating CHN composition, conductometric titration, and degree of deacetylation, in conjunction with their associated errors, were developed and reported in this note. Error analysis showed conductometric analysis as an inexpensive and secure method for the determination of the degree of deacetylation of chitosan.

An analytical method based on liquid chromatography with positive ion electrospray ionization (ESI) coupled to tandem mass spectrometry detection was developed for the determination of lansoprazole in human plasma using omeprazole as the internal standard. The analyte and internal standard were extracted from the plasma samples by liquid-liquid extraction using diethyl-ether-dichloromethane (70:30; v/v) and chromatographed on a C(18) analytical column. The mobile phase consisted of acetonitrile-water (90:10; v/v)+10 mM formic acid. The method has a chromatographic total run time of 5 min and was linear within the range 2.5-2000 ng/ml. Detection was carried out on a Micromass triple quadrupole tandem mass spectrometer by Multiple Reaction Monitoring (MRM). The intra- and inter-run precision, calculated from quality control (QC) samples, was less than 3.4%. The accuracy as determined from QC samples was less than 9%. The method herein described was employed in a bioequivalence study of two capsule formulations of lansoprazole.