A review from 1996 to 2021 of tuning methodologies and controller structures applied for an unstable/stable (bio)reactor with imperfect mixing and bypass.

This paper presents a critical review of tuning methodologies and controller structures applied to the Cholette bioreactor. This (bio)reactor has been studied extensively by the automatic control community from the point of view of controller structures and tuning methodologies, from controllers with a single structure to nonlinear controllers, and from the synthesis method to the frequency response. Therefore, new trends and opportunities of study have been detected with regard to their operating points, controller structures and tuning methodologies which could be addressed for this system.

Human and ecotoxicological impacts assessment from the Mexican oil industry in the Coatzacoalcos region, as revealed by the USEtox model.

Human and ecotoxicological impacts were analyzed in the lower basin of the Coatzacoalcos River (Veracruz, State in Mexico). High pollution levels of contaminants from the oil industry have been reported in natural streams and the Coatzacoalcos River and in their sediments. USEtox model was employed to evaluate environmental fate, exposure, and effect of nine organic compounds (polycyclic aromatic hydrocarbons and one of which was in the group of polychlorinated biphenyls), a heavy metal (lead), and the effect of the industrial wastewater emitted into the river, on the Coatzacoalcos region. Most of these compounds are highly toxic; they bioaccumulate in human and animal tissue, mainly in the fatty tissues and can damage different organs and systemic targets such as the liver, kidney, hormonal system, nervous system, etc., of both humans and wildlife. The model estimates that 96% (3,247 kg/day) of organic compounds is transferred from the water into air, whereas only 4% (151 kg/day) remains in the water. In addition, it predicts that humans are mainly exposed to polychlorinated biphenyls (PCBs) congeners (28 and 153) by eating contaminated fish, due to PCBs accumulating in the fish fat tissue. The number of cases of cancer and noncancer (1 in 862 habitants per additional kilogram) is expected to have an increment due to the higher PCBs exposure of human population. Genetic damages in fishes, earthworms, and toads have been observed and related to higher exposure to organic compounds. The relationship between the field reported data and those one predicted by the USEtox model have been confirmed empirically by using the nonparametric correlation analysis (Spearman's rho). Based on the USEtox model, the environmental stress in the Coatzacoalcos industrial zone is between 2 and 6 orders of magnitude over geometric mean of acute aquatic EC50s. We think that USEtox model can be used to expand the number of substances that have the current water quality guidelines to improve the water management in Mexico.

Evaluation of the tolerance of acetic acid and 2-furaldehyde on the growth of Pichia stipitis and its respiratory deficient.

The use of lignocellulosic residues for ethanol production is limited by toxic compounds in fermenting yeasts present in diluted acid hydrolysates like acetic acid and 2-furaldehyde. The respiratory deficient phenotype gives the cell the ability to resist several toxic compounds. So the aim of this work was to evaluate the tolerance to toxic compounds present in lignocellulosic hydrolysates like acetic acid and 2-furaldehyde in Pichia stipitis and its respiratory deficient strains. The respiratory deficient phenotype was induced by exposure to chemical agents such as acriflavine, acrylamide and rhodamine; 23 strains were obtained. The selection criterion was based on increasing specific ethanol yield (g ethanol g(-1) biomass) with acetic acid and furaldehyde tolerance. The screening showed that P. stipitis NRRL Y-7124 ACL 2-1RD (lacking cytochrome c), obtained using acrylamide, presented the highest specific ethanol production rate (1.82 g g(-1 )h(-1)). Meanwhile, the ACF8-3RD strain showed the highest acetic acid tolerance (7.80 g L(-1)) and the RHO2-3RD strain was able to tolerate up to 1.5 g L(-1) 2-furaldehyde with a growth and ethanol production inhibition of 23 and 22 %, respectively. The use of respiratory deficient yeast phenotype is a strategy for ethanol production improvement in a medium with toxic compounds such as hydrolysed sugarcane bagasse amongst others.

Effect of Hibiscus sabdariffa L. dried calyx ethanol extract on fat absorption-excretion, and body weight implication in rats.

The effect of Hibiscus sabdariffa L. (Hs) calyx extract on fat absorption-excretion and body weight in rats, was investigated. Rats were fed with either a basal diet (SDC = Control diet) or the same diet supplemented with Hs extracts at 5%, 10% and 15% (SD(5), SD(10) and SD(15)). Only SD(5) did not show significant increases in weight, food consumption and efficiency compared to SD(C). The opposite occurred in SD(15) group which showed a significant decrease for these three parameters. The SD(10) responses were similar to SD(15), with the exception of food consumption. In both SD(C) and SD(5) groups, no body weight loss was observed; however, only in the latter group was there a significantly greater amount of fatty acids found in feces. A collateral effect emerging from the study is that components of Hs extract at the intermediate and greater concentrations used in this experiment could be considered possible antiobesity agents.