Synthesis,spectral properties,and application of 1,8‐naphthalimide fluorophores for modified polymers

The presence of the epoxy group in the structure of 1,8‐naphthalimide fluorophores opens up possibilities to prepare compounds with new valued properties through covalent bonding to both polyamide and epoxy oligomers. Two new 4‐(1‐amino‐2,3‐epoxypropyl)‐9‐substituted‐1,8‐naphthalimides were synthesized, and their absorption and fluorescence characteristics were determined. The introduction of the substituent contributes to both the yellow color and strong fluorescence of the compounds, the quantum yield being about 0.9. The possibility for structural coloration of polyamide textile materials and epoxy oligomers has been investigated. The modified polymers are with intense green fluorescence, possessing a strong resistance to various physico‐chemical treatments and light. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1863–1869, 2001     

Synthesis and application of Fluorescent Dyes on basis of 1,8-naphthalic carboximides

The naphthalimide derivatives ( 2a–g, 3a–e ) were synthesized from 1,8-naphthalic carboximides. They show green fluorescence, and are suitable for dyenig of textile materials and epoxy resins. The colour parameters of the dyed fabrics were measured. The assessment of colour was made in terms of CIE tristimulus values as well as the position of colour in CIELAB coordinates (L*, a*, b*). The correlation between colour and structure of the dyes is discussed.     

Fluorescent polyacrylonitrile with 1,8-naphthalimide side chains

The copolymerization of acrylonitrile with two polymerizable fluorescent naphthalimide dyes has been investigated. It was found that the monomeric dyes took part in the polymerization and 94–96% of initially 1 wt.-% (relative to acrylonitrile) were covalently bound in the polymer chain, and thus new fluorescent side-group copolymers were obtained. The absorption and basic photophysical characteristics of monomeric naphthalimid dyes and copolymers in dimethylformamide are reported.     

A Galantamine–Curcumin Hybrid Decreases the Cytotoxicity of Amyloid-Beta Peptide on SH-SY5Y Cells

Misfolded amyloid beta (Aβ) peptides aggregate and form neurotoxic oligomers. Membrane and mitochondrial damages, calcium dysregulation, oxidative stress, and fibril deposits are among the possible mechanisms of Aβ cytotoxicity. Galantamine (GAL) prevents apoptosis induced by Aβ mainly through the ability to stimulate allosterically the α7 nAChRs and to regulate the calcium cytosolic concentration. Here, we examined the cytoprotective effects of two GAL derivatives, namely compounds 4b and 8, against Aβ cytotoxicity on the human neuroblastoma cell line SH-SY5Y. The protective effects were tested at simultaneous administration, pre-incubation and post-incubation, with Aβ. GAL and curcumin (CU) were used in the study as reference compounds. It was found that 4b protects cells in a similar mode as GAL, while compound 8 and CU potentiate the toxic effects of Aβ. Allosteric stimulation of α7 nAChRs is suggested as a possible mechanism of the cytoprotectivity of 4b. These and previous findings characterize 4b as a prospective non-toxic multi-target agent against neurodegenerative disorders with inhibitory activity on acetylcholinesterase, antioxidant, and cytoprotective properties.     

Photoactive mussels inspired polymer coatings: Preparation and antibacterial activity

In this article we report on the facile preparation of photoactive antibacterial mussel inspired polymer coatings deposited on a stainless steel (SS) substrate from water based precursors. The coating is prepared by the sequential deposition of aqueous based solutions of an anchoring layer based on bio-inspired glue, a cationic polymer bearing pendent catechols, a nanogel decorated by ortho-quinones and a photosensitizer of the aminoacridine type. This latter is grafted to the coating by reaction of its amino group with the o-quinone of the deposited nanogel. The deposition of all layers is followed in-line by Quartz crystal microbalance coupled with dissipation (QCM-D) and AFM shows that the thin polymer film repeated the roughness of the SS substrate. The prepared coatings show good mechanical properties applying nanoindentation techniques. The established antibacterial activity of the prepared photoactive polymer coatings on SS against Gram-negative E. coli strain demonstrate their potential as a power tool for medical applications.     

Electromyographic activity of respiratory muscles under hyperbaric conditions

Two subjects were exposed to neon gas mixture and two others--to helium one. Electromyographic activity of their breathing muscles differed between the two groups depending on both the gas mixture and the steps of compression. Obvious difficulties of breathing with the neon hyperbaric mixture were accompanied by depressing of the EMG amplitude, episodic breaches or hyperactivation of the EMG. The findings suggest a predominant role of the diaphragm activity in hyperbaric conditions.     

Detection of specific RNA sequences in yeast by in situ colony hybridization

Recently a convenient method for detection of specific RNA sequences in bacteria has been developed but the original protocol was inapplicable to microorganisms with a rigid cell wall. Here we report a modification of the RNA colony hybridization for use with yeast. The modified method includes the following consecutive procedures: a) treatment of the yeast colonies on the membrane filter with 10% SDS at 65% C for 30 min; b) treatment of the same filter with 3 x SSC, 10% formaldehyde at 65 degrees C for 30 min; c) hybridization with 32P-labelled oligonucleotide (or DNA) specific for the RNA sequence of interest. The intensity of the radioactive signals thus obtained is comparable with that of the E. coli colonies.     

Cell fusion of Saccharomyces cerevisiae fragile mutants

Fragile mutants of Saccharomyces cerevisiae are defective in the structure of the cell wall and plasma membrane. The mutant cells lyse in hypotonic solutions but grow exponentially when osmotic stabilizer is included in the medium. These mutants display a general increase in the permeability of the plasma membrane. We show here that fragile yeast cells of the same mating type can fuse without protoplast formation. The frequency of cell x cell fusion is lower than that observed for protoplast x protoplast fusion and can be significantly increased if the cells of one partner are converted to protoplasts. Microscopic observations and genetic analysis demonstrate that the hybrids obtained are fusion products. The fusion between fragile cells is explained in terms of the existence of local defects on their surface where the cell wall is thinner (or even missing), thus allowing a direct contact of cells by means of their plasma membranes.     

Studies of phenolic resin-based microporous separator materials

A method is described for the preparation of phenolic resin-based microporous separator materials with improved high-temperature, acid and oxidation resistance. The effect of the degree of polycondensation of the resin, the quantity of modifying agent, the duration of modification, the ageing time of phenolic resin, the quantity of catalyst, and the pre-curing temperature of the resin upon the properties of the separator material were studied in an effort to improve the separator. The electrical resistance, pore size and volume porosity of separator samples were determined.     

Occupational role stress in the Canadian forces: Its association with individual and organizational well-being.

Studies on workplace stress have been conducted in various occupational environments. However, published reports exploring occupational stress in the military are rare. This study examines occupational stress in the Canadian Forces within the framework of social role theory and its relation to employee health, job satisfaction, and organizational commitment. Ss were 1,068 Regular Forces military members who completed a survey questionnaire. Of interest were the psychological resources (e.g., individual coping skills, workplace leadership, and perceived organizational support) that have the potential to alter the perception of work stress and/or alleviate its association with individual and organizational outcomes. Regression analyses indicated a negative association between occupational role stress and both individual (strain) and organizational (job satisfaction and organizational commitment) well-being. No moderating effects were found for coping strategies, workplace leadership, or perceived organizational support, although these factors had direct relationships with both individual and organizational well-being The results are discussed in terms of the potential of organizational resources and role stress to cascade across organizational levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)