Synthesis, antioxidant, and molecular docking of new fluorescent (4-alkoxyphenyl)-nitrothiophene compounds.

New fluorescent 4-alkoxyphenyl-nitrothiophene compounds 4a-d bearing diverse alkoxyl tails are described. The synthetic strategy was simply accomplished by alkali-assisted alkylation of 4-(5-nitrothiophen-2-yl)phenol (3) with propyl, hexyl, nonyl, and/or dodecyl iodide. The molecular structures were determined using infrared (IR), 1 H NMR, and mass spectroscopy. Ultraviolet-visible (UV-vis) absorption and emission spectra of the produced 4-alkoxyphenyl-nitrothiophenes revealed considerable extinction coefficients, which were shown to be controlled by the thiophene bridge in conjugation with the alkoxy donor moiety. It was found that the maximum absorbance wavelength was affected by the alkoxyl group-bonded substituents. The antioxidant efficiency obtained from the 4-alkoxyphenyl-nitrothiophene hybrids was excellent compared with that widely used drugs [butylated hydroxytoluene (BHT) and vitamin C]. Unlike 2-(4-[dodecyloxy]phenyl)-5-nitrothiophene hybrid 4d, which has made solid claims about the good effect of its reference drugs and vitamins, Docking investigations of the prepared 4-alkoxyphenyl-nitrothiophene hybrids towards the selected 5IKQ protein revealed impressive coordination and antioxidant effectiveness.

Spatial contagion between financial markets: new evidence of asymmetric measures.

The objective of this paper is to identify the presence, direction and time at which the pure contagion effect occurred between financial markets. In so doing, the aim is to prove the existence of both spatial and temporal asymmetries of pure contagion effects. Firstly, a new empirical framework is proposed in order to define a spatial contagion index using the conditional cumulative distribution function as a parameter to estimate a conditional copula. This methodology enables us to estimate a dynamic conditional copula, providing information about how the market sent pure contagion effects and when. Secondly, in addition to detecting the direction of contagion, the real-time contagion effect is determined, enabling us to calculate the delay of contagion effects (spillover) between financial markets. The present empirical results show the existence of both spatial and temporal asymmetry for bilateral contagion effects for 16 mature and emerging stock markets during the 2001-2018 period. This proves the importance of taking temporal asymmetry into account when we want to detect the contagion effect of every crisis and to estimate the period of pure contagion relating to investors' behaviors. Finally, these findings highlight the fact that contagion effects were more intensive during the subprime crisis than they were during the European debt crisis.

Chitosan hydrogel-coated cellulosic fabric for medical end-use: Antibacterial properties, basic mechanical and comfort properties.

This study explores the influence of functionalization process of cellulosic structure on its mechanical and comfort properties. Chitosan hydrogel has been synthetized and applied on cellulosic fabric to impart pH-sensitivity and antimicrobial behavior. The hydrogel bounded rate onto the surface was enhanced by a previous chemical activation of cotton fabric. Antimicrobial behavior was confirmed by investigation of the antibacterial activities against Escherichia coli, Listeria monocytogene and Staphylococcus aureus bacteria. The pH stimuli-responsiveness behavior was also confirmed and the pH-dependency swelling of the chitosan hydrogel was successfully transformed into cellulosic sites. The resulting fabric was confirmed suitable for medical, surgical and also transdermal therapy applications. Meanwhile, these modifications have unexpectedly altered basic mechanical and comfort properties. It was established that the proposed antimicrobial treatment caused slight decrease in air permeability and made the support thickener. The obtained results revealed also that tensile behavior and the ultimate comfort properties were greatly influenced by the chemical activation.

Antifouling processes and toxicity effects of antifouling paints on marine environment. A review.

The production infrastructure in aquaculture invariably is a complex assortment of submerged components with cages, nets, floats and ropes. Cages are generally made from polyamide or high density polyethylene (PEHD). All of these structures serve as surfaces for biofouling. However, cage nets and supporting infrastructure offer fouling organisms thousands of square meters of multifilament netting. That's why, before immersing them in seawater, they should be coated with an antifouling agent. It helps to prevent net occlusion and to increase its lifespan. Biofouling in marine aquaculture is a specific problem and has three main negative effects. It causes net occlusion and so restricts water and oxygen exchange. Besides, the low dissolved oxygen levels from poor water exchange increases the stress levels of fish, lowers immunity and increases vulnerability to disease. Also, the extra weight imposed by fouling causes cage deformation and structural fatigue. The maintenance and loss of equipment cause the increase of production costs for the industry. Biocides are chemical substances that can prohibit or kill microorganisms responsible for biofouling. The expansion of the aquaculture industry requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. Unfortunately, the use of biocides in the aquatic environment has proved to be harmful as it has toxic effects on the marine environment. The most commonly used biocides in antifouling paints are Tributyltin (TBT), Chlorothalonil, Dichlofluanid, Sea-Nine 211, Diuron, Irgarol 1051 and Zinc Pyrithione. Restrictions were imposed on the use of TBT, that's why organic booster biocides were recently introduced. The replacement products are generally based on copper metal oxides and organic biocides. This paper provides an overview of the effects of antifouling biocides on aquatic organisms. It will focus on the eight booster biocides in common use, despite little data are available for some of them. Toxicity values and effects of these antifoulants will also be mentioned for different species of fish, crustaceans, invertebrates and algae.