The objective of the work reported here was to determine the influence of UV radiation and environmental temperature on the strength and rheological characteristics of multilayer agricultural packaging foils. The transmission properties of the experimental foils were tested in 286–363.5 nm range. The analysis of transmission properties of the foils showed that the maximum transmission was 10 % and 45 % with the experimental violet foils having 20 % and 5 % UV inhibitor in them, respectively. However, the transmission was higher than 80 % with the white foils of 5 % and 20 % inhibitor.The effect of the temperature on the tensile stress of commercial foils was investigated gated in the −20 ≤
≤ 50 °C temperature range. The measured relaxation curve was found to have a close correlation both for −10°C and 45°C with the calculated results. The highest reduced strength decreased as the function of the temperature according to the σ= −0,1861
+19,107 [MPa] equation. Therefore, the probability of the break of the foils in cold weather is definitely higher than under warm weather conditions.
Authors:C. Bentivoglio Ruiz, L. Machado, J. Volponi, and E. Segura Pino
Radiation curing is an environmentally-friendly technology. Furthermore, radiation curing is a faster, energy saving and more
efficient industrial process than the heat-curable process. One of the most important requirements for the widespread application
of UV curable coatings in the coating industry is that they are stable vs. atmospheric degradation. Today's state of the art
in oxidative drying and thermosetting coatings is the use of light stabilizers to protect polymers vs. the damage of outdoor
exposure. Oxygen has a detrimental effect on the cure response of free radical systems, especially in thin-film coatings.
Differential photocalorimetry (photo-DSC) was used to investigate the oxygen effect and the use of light stabilizers on UV
curing of photocurable formulations based on acrylate materials. Coating thickness influence was also considered.
Authors:Lidija Ćurković, Davor Ljubas, and Hrvoje Juretić
The efficiency of color removal from aqueous Congo Red dye (CR) solution has been investigated in TiO2 suspensions irradiated with artificial UV light. Batch photocatalytic tests were carried out by varying the amount of TiO2 and the irradiation time using the same initial CR concentration. The experimental results indicated that the decolorization
rate follows pseudo first-order kinetics with respect to CR concentration. The doses of TiO2 were 0.25, 0.5 and 1.0 g L−1 and the wavelength of incident ultraviolet light was predominantly 254 nm. CR adsorption on the surface of TiO2 is also investigated and described.
Authors:Yonca B. Kabak, Mahmut Sozmen, Alparslan K. Devrim, Mert Sudagidan, Funda Yildirim, Tolga Guvenc, Murat Yarim, Yavuz M. Gulbahar, Ishtiaq Ahmed, Efe Karaca, and Sinem Inal
skin and oral cavity, respectively ( Miller et al., 1991 ). FSCC is a multifactorial neoplasm and its prevalence is mostly related to exposure to solar UVradiation; it may be preceded by epidermal dysplasia and actinic keratosis ( Gross et al., 2005
Authors:D. Turgut-Balik, V. Çelik, Kath Moreton, and R. L. Brady
In this study, lactate dehydrogenase gene from Plasmodium vivax has been tried to subclone into an expression vector. Some of the Plasmodium falciparum lactate dehydrogenase mutant genes have also been tried to clone and subclone into a vector, but we failed to clone or subclone either of the genes. DNA visualisation in electrophoretic gels typically requires UV radiation and the fluorecent dye ethidium bromide. A crystal violet-stained gel was run instead of an ethidium bromide gel and so avoided the use of UV radiation. This enabled us to clone or subclone both Plasmodiumvivax lactate dehydrogenase gene and Plasmodiumfalciparum lactate dehydrogenase mutant genes into any desired vector.
The determination of thallium with potassium chlorate is chosen as an example for the earlier suggested new radio-oxidimetric
titration procedure, in which phase separation is achieved by means of a strongly basic anion exchanger in the solution. Concentrations
of thallium down to 2·10−6M have been determined. Special care has to be taken for concentrations lower than 10−5M as UV radiation is a disturbing factor. Other oxidizing agents have also been tested.
In this study, thin-layer chromatography with densitometry and gas chromatography—mass spectrometry (GC—MS) were used to evaluate the chemical stability of hexyl nicotinate. Normal-phase thin-layer chromatography (NP-TLC) analysis was performed on silica gel 60 F254 plates with acetone—n-hexane in volume composition of 30:70 (v/v) as the mobile phase. The investigation of the chemical stability of hexyl nicotinate was performed in aqua—ethanolic solutions stored in ordinary and quartz flasks heated at 40°C and exposed to ultraviolet (UV) radiation (λ = 254 nm). Hexyl nicotinate was stable in aqua—ethanolic solution stored in ordinary flasks heated to 40°C and exposed to UV radiation (λ = 254 nm). Based on GC—MS analysis, the preliminary identification of the decomposition products of hexyl nicotinate in aqua—ethanolic solution, which was exposed to UV radiation (λ = 254 nm) in a quartz flask for 200 h, was achieved. Thermogravimetric analysis showed the complete disappearance of hexyl nicotinate at a temperature of 392.2°C.
Authors:Andreas Erich Zautner, Annina Hage, Katja Schneider, Karolin Schlösser, Ortrud Zimmermann, Else Hornecker, Rainer F. Mausberg, Hagen Frickmann, Uwe Groß, and Dirk Ziebolz
It is well known that dental caries and periodontitis are the consequence of bacterial colonization and biofilm formation on the enamel surface. The continuous presence of bacterial biofilms on the tooth surface results in demineralization of the tooth enamel and induces an inflammatory reaction of the surrounding gums (gingivitis). The retention and survival of microorganisms on toothbrushes pose a threat of recontamination especially for certain patients at risk for systemic infections originating from the oral cavity, e.g., after T-cell depleted bone marrow transplantation. Thus, the effects of different decolonization schemes on bacterial colonization of toothbrushes were analyzed, in order to demonstrate their applicability to reduce the likelihood of (auto-)reinfections.
Toothbrushes were intentionally contaminated with standardized suspensions of Streptococcus mutans or Staphylococcus aureus. Afterwards, the toothbrushes were exposed to rinsing under distilled water, rinsing and drying for 24 h, 0.2% chlorhexidine-based decolonization, or ultraviolet (UV) radiation. The remaining colony forming units were compared with freshly contaminated positive controls. Each experiment was nine-fold repeated. Bi-factorial variance analysis was performed; significance was accepted at P < 0.05.
All tested procedures led to a significant reduction of bacteral colonization irrespective of the toothbrush model, the brush head type, or the acitivity state. Chlorhexidine-based decolonization was shown to be superior to rinsing and slightly superior to rinsing and drying for 24 h, while UV radiation was similarly effective as chlorhexidine. UV radiation was slightly less prone to species-dependent limitations of its decolonizing effects by bristle thickness of toothbrushes than chlorhexidin.
Reduction of bacterial colonization of toothbrushes might reduce the risk of maintaining bacterial infections of the upper respiratory tract. Accordingly, respective procedures are advisable, particularly as they are cheap and easy to perform.
Using laboratory experiments, the
daily activity patterns of 16 Neuroptera species (6 Chrysopidae, 2
Coniopterygidae, 3 Hemerobiidae, 3 Myrmeleontidae, 1 Mantispidae, 1
Ascalaphidae) were studied by the authors. The results of the experiments were
described by activity diagrams and were categorized into Duelli-type flight
activity pattern. During the study, 14 species showed carnea type of nocturnal
activity. Mantispa styriaca proved to belong to hypochrysodes type which is
active at daytime. The daily activity pattern of Libelloides macaronius differs
from the hypochrysodes type due to its strong preference of UV radiation;
therefore it is described as a separate libelloides type.