Irreducible complexity of iterated symmetric bimodal maps

We introduce a tree structure for the iterates of symmetric bimodal maps and identify a subset which we prove to be isomorphic to the family of unimodal maps. This subset is used as a second factor for a $\ast$-product that we define in the space of bimodal kneading sequences. Finally, we give some properties for this product and study the *-product induced on the associated Markov shifts

Trichothecenes NIV and DON modulate the maturation of murinedendritic cells

Nivalenol (NIV) and Deoxynivalenol (DON), mycotoxins of the trichothecene family are considered very common food contaminants. In this work, we investigated whether the immunotoxic effects ascribed to these trichothecenes may be mediated by perturbations in the activity of dendritic cells (DCs). Murine bone marrow-derived DCs were used to evaluate the effects of NIV and DON on the LPS-induced maturation process.We found that the expression of the class II MHC and of the accessory CD11c molecules, but not of the costimulatory CD86 marker, was down-regulated by NIV and DON exposure in LPS-treated DCs, as well as nitric oxide (NO) production. Interestingly, NIV, but not DON, induced DC necrosis. Moreover, the analysis of the cytokine pattern showed that IL-12 and IL-10 expressions induced by LPS exposure were suppressed by both trichothecenes in a dose-dependent fashion. On the other hand, the secretion of the proinflammatory cytokine TNFa was increased as a direct consequence of DON and NIV exposure. Taken together, our data indicated that the immunotoxicity of NIV and DON was related to the capacity of both trichothecenes to interfere with phenotypic and functional features of maturing DCs

Bowen–Franks groups of reducible bimodal subshifts of finite type

AbstractWe study the Bowen–Franks groups of subshifts of finite type associated with reducible bimodal periodic kneading sequences pairs

EFFECTS OF NDL-PCB ON PORCINE MACROPHAGES: PRELIMINARY RESULTS

Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) causing adverse effects on both humans and animals. Immune system is an important target organ for many environmental contaminants. Macrophages constitute an important component of the immune system of humans and animals, in fact, they are responsible for triggering innate immune responses and host defense. The aim of the current study was to assess the immunomodulatory effects of certain non dioxin like PCBs (PCB 138; PCB 153 and PCB 180) using porcine macrophage 3D4/31 cell line. We evaluated not only the effects induced by the individual congeners but also those deriving from mixtures of more contaminants, in consideration of the fact that co-contamination of the same substrate is common in natural conditions and the effects of simultaneous exposure to multiple contaminants are still little investigated. The results of the current study showed that ndl-PCBs reduced significantly cell viability only at the highest concentration (50 µM); such effect was not linked to apoptosis induction or cell cycle arrest. The contemporary presence of more than one contaminant (differently combined) did not induce any enhancement of effects on 3D4/31 cell line

In-house validation of chromatographic speciation methods for arsenic in fishery products

The relatively high concentrations of arsenic found in shellfish in recent years have contributed to raise the threshold of attention of European Union, in terms of food security. Among the various factors that influence the toxicity of arsenic, the chemical form is of particular significance, given the high toxicity of the inorganic form in respect of the organic that frequently contaminates fishery products. The Expert Committee of FAO / WHO defined a provisional tolerable weekly intake (PTWI) of 15 mg/kg b.w. only for the inorganic form and, in view of definition of residual limits for arsenic in fish, it becomes necessary to have analytical methods able to differentiate inorganic form from the organic ones (e.g. monomethyland dimethylarsenic acid, arsenobetaine, arsenocholine). The purpose of this study was to optimize and validate an analytical method for the speciation of arsenic in fishery products, that could identify and quantify the organic forms of arsenic. Screening of organic forms of arsenic was carried out using HPLC (high performance liquid chromatography) coupled to a tandem mass spectrometry detector, while determination of total arsenic was carried out using the atomic absorption spectroscopy. The validation procedure was conducted according to the requirements of the European Community to allow the use of the present method by the Official Control laboratories. The matrices considered for method optimization and validation have been fish, molluscs and crustaceans from the coasts of southern Italy. Obtained results allowed the method to enter within the routinely activities of the laboratory and require method accreditation

Students’ Modular Learning Experiences Amidst Pandemic: A Basis for Recovery Plan

The researchers of this study determined the experiences of students to modular learning, the things that they like most about the module, and the students’ priorities for the improvement of the module. The researchers employed the descriptive-survey design and the subjects of this study were 102 officially enrolled Grade 11 and Grade 12 Academic and TVL students of Juban National High School during the school year 2021-2022 and used adopted questionnaire. Findings revealed that the majority of the respondents had positive responses about the quality of the module. Moreover, there are things that the students like most about the module. Still, they have priorities to improve the module. The researchers recommended that the continuous improvement of the learning module must be done across the subject areas. Keywords: Modular Learning, COVID-19 Pandemic, Learning Experiences, Recovery Plan DOI: 10.7176/JEP/14-7-03 Publication date:March 31st 202

Method for speciation of organoarsenic in mussels by liquid chromatography coupled to electrospray ionization and QTRAP tandem mass spectrometry.

Arsenic toxicity to humans critically depends on the chemical form of the arsenic. The Expert Committee of the Food and Agriculture Organization and the World Health Organization defined a tolerable intake only for inorganic arsenic, although the toxicity of some organoarsenic compounds is known. Arsenobetaine (AsB), arsenocholine (AsC), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) are abundant in shellfish. We present a fast and reliable method for identification of the type of organic arsenic in mussels by using liquid chromatography coupled to electrospray ionization tandem mass spectrometry on triple quadrupole with parallel determination of total arsenic by atomic absorption spectrophotometry. The method was validated by evaluating mean recoveries, repeatability, specificity, limits of quantification, and limits of detection that produced satisfactory results. The method was used to carry out the first survey of the concentrations of AsB, AsC, MMA, and DMA in seafood from southern Italy. Total As concentrations ranged from 1.38 to 12.79 mg/kg. AsB and DMA were detected in all samples (AsB: 0.72 to 10.36 mg/kg; DMA: 0.28 to 1.08 mg/kg), and concentrations of AsC and MMA ranged from 0.20 to 1.53 mg/kg. This method allowed us to rapidly and inexpensively identify arsenic types in fishery products and would be suitable for routine detection of organoarsenic compounds in molluscs