Photocrosslinking of an Acrylated Epoxidized Linseed Oil: Kinetics and its Application for Optimized Wood Coatings

Over the past few decades, the industry developed an increasing interest in using renewable, bio-based thermosetting polymers as matrix systems for composites and coating systems. In the present paper an acrylated epoxidized linseed oil (AELO) was synthesized from epoxidized linseed oil (ELO) through ring opening of the oxirane group using acrylic acid as the ring opening agent. The synthesized AELO was mixed with three different photoinitiators and cured under monochromatic conditions (???=?365?nm) at different light intensities and at different temperatures. The concentration of the initiators was aligned that all initiators absorb at 365?nm the same amount of light. The evolution of cure was monitored by using real-time infrared spectroscopy with a heated attenuated total reflection unit. The decrease of absorption in the measured spectra at 1,406?cm^?1 was used to calculate the conversion of acrylic double bonds with increasing time of UV light exposure to get information about the cure kinetics for each AELO mixture at different light intensities and different temperatures. Wood substrates were coated in a preliminary work with the AELO mixtures and after UV-curing some technological coating properties like gloss, scratch resistance, adhesion, and solvent resistance were tested. In combination with the information about the cure kinetics in the present work the coating properties were correlated with the cure evolution and the final degree of double bond conversion. The found correlation can be used in the future to find optimized coating conditions for the AELO mixtures on wood substrates.     

Fatty acid composition of marine macroalgae from the Black Sea and Dardanelles

The fatty acid (FA) composition was determined in 14 species of marine macroalgae belonging to the Chlorophyta, Phaeophyta and Rhodophyta, which were collected from ?ile in the Black Sea and Kepez in the Dardanelles. Generally, polyunsaturated FAs and monounsaturated FAs were major components (50–77%). Total saturated FAs ranged from 22% to 50%, with 16?:?0 as the most abundant saturate (32–38%). Two samples of Cystoseira barbata collected from a different station had some differences from each other in their contents of 18?:?2n-6 and 18?:?3n-3 and in the 18?:?2n-6/20?:?4n-6 ratios. Green algal species had a significantly higher proportion of unsaturated FAs and a significantly lower proportion of saturated FAs than the red and brown algae. The amount of n-3 FAs was significantly higher in Ulva rigita, Chaetomorpha linum, Enteromorpha linza and Gracilaria verrucosa (8.88, 6.44, 5.31 and 5.24, respectively).     

Adult respiratory distress syndrome in human organophosphate poisoning cases

Adult respiratory distress syndrome (ARDS) is a clinical syndrome which occurs due to various direct or indirect noxious agents and pyhsical mechanisms. One of the etiological factors is ingested chemicals (e.g. paraquat, ethylene glycol). The organophosphorous (OP) insecticides are the most toxic and frequently encountered chemicals that produce poisoning in humans. Studies were undertaken to investigate whether OP insecticides may produce ARDS. Fifteen autopsy cases due to suicidal OP insecticide poisoning were investigated. Toxicological analyses were performed with a gas chromatography-nitrogen phosphorous detector (GC-NPD). Methamidophos, dimefox and dichlorvos were the detected OP. Lungs were examined macroscopically. Two cases showed features compatible with ARDS in which the only cause of death was OP poisoning. Due to the severity of ARDS it is important to assess insecticidal exposure in an attempt to enhance survival patterns following OP poisoning in patients in order to initiate therapy.     

The effects of pesticides on greenhouse workers and their produced products

Pesticides are chemicals used in agriculture but are known to produce adverse effects on humans. In this study, blood activities of superoxide dismutase (SOD), catalase (CAT), aspartate transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transaminase, lactate dehydrogenase (LDH), and levels of malondialdhyde (MDA) were determined in 44 greenhouse workers (24 tomato workers, 20 clove workers) and in tomato (24 samples) and clove (20 samples) products. At the end of this study, blood MDA levels and activities of ALT, AST, and LDH levels in greenhouse workers were significantly increased while SOD and CAT activity levels fell significantly. Pesticide residues were not found in agricultural worker blood. Malathion residues (average 0.8?ppm) were detected in tomatoes (8 samples) in these greenhouses. Data suggest that the health of the greenhouse workers may be adversely affected by pesticides.     

Cadmium accumulation by green algae Cladophora glomerata (L.) Kutz. (Chlorophyta) in presence of Nile tilapia Oreochromis niloticus (L.)

Accumulation of metals by aquatic organisms is mostly affected by other biological components in environments. In this study, cadmium (Cd) accumulation in green algae, Cladophora glomerata (L.) Kutz., exposed to 0.1 and 1.0 mg L^?1 of Cd for 15 and 30 days was examined in laboratory conditions in the presence of Nile tilapia Oreochromis niloticus (L.). The green algae C. glomerata accumulated Cd concentrations as 690 ± 70 and 3430 ± 470 mg kg^?1 on day 15, and 1130 ± 180 and 6830 ± 1540 mg kg^?1 on day 30. There were significant increases (p < 0.05) in metal accumulation by green algae as the exposure time and metal concentration increased. The results also indicated that the presence of Nile tilapia in the medium led to a significant Cd accumulation in the green algae compared to control (p < 0.05).     

Voltammetric studies of damages in DNA by mutagenic and carcinogenic alkylating chemicals

Voltammetry provides new insights into the effects exerted in vitro by methylation of native DNA. Applying single sweep voltammetry at a stationary mercury electrode the successive steps of the destabilization of alkylated DNA are investigated. The methylation of the nucleic acids is manifested by a specific electrochemical response, due to the 7‐methylguanine, a major product of the methylation of DNA. Short time effects of the methylation include the labilization of 4 to 5 base pairs per methylated guanine base. Furthermore, uncommon protonation properties of the base 7‐methylguanine‐cytosine have been detected. Long term effects of the methylation are ultimately spontaneous hydrolytic strand breaks induced by the prior depurination connected with the release of the 7‐methylguanine from the methylated DNA. A half time t_1/2 of 102 h for the depurination at 37°C has been determined. The depurination and the subsequent strand breaks alter the hydrodynamic properties of the damaged DNA, an effect which can be sensitively followed with voltammetry via the resulting changes in the diffusion coefficient of the damaged biopolymer.     

Analysis of insecticide “Toxaphene”; in fish products

The gaschromatographic determination of Toxaphene in the presence of other chlorinated hydrocarbons with similar retention times is often difficult. The practibility of a new method, based on photodehalogenation of the interfering substances, is shown during the analytical determination of Toxaphene residues in selected environmental samples, especially in fish and fish products. Irradiation of the extracts after clean‐up procedures with wavelengths at 254 nm lead directly to photodechlorination products of interfering substances with shorter retention times and makes it possible to determine the Toxaphene components quantitatively, which are mostly stable under the same experimental conditions.     

Indoor air pollution: A review∗

Relationships between toxicities of substituted aromatic hydrocarbons to Daphnia magna and to Fathead minnows or Photobacterium phosphoreum were studied based on structure‐activity equations we established. Good relationships between toxicities of chemicals to Daphnia magna and to Fathead minnows, Photobacterium phosphoreum were found for a wide range of chemicals. The toxicity data of fish can be predicted by the toxicity data of Daphnia magna or Photobacterium phosphoreum. It is probable that the toxicities of chemicals to the three organisms are similar.     

Databanks of data sources for environmental chemicals

There exist a vast variety of data sources, either manual sources or computerized databases in the field of environmental chemicals. To facilitate the access and to retrieve the information wanted efficiently, we built up two “databanks of data sources”, one called “Databank of Manual Sources (DMAS)” and the other named “Databank of Databases (DADB)”. The set‐up of these databanks is explained and the load status statistics are shown. DMAS has 164 and DADB 106 hits.