Effects of environmental factors on seasonal and spatial changes in surface zooplankton in Golden Horn Estuary (Istanbul,Turkey)

The abundance and spatial distribution of zooplankton at monthly intervals were studied in polluted Golden Horn Estuary (Istanbul, Turkey), from July 2006 to December 2007. Selected water quality parameters also were measured. The zooplankton community was characterized by the presence of freshwater, estuarine and marine species, with a total of 59 taxa. Rotifers were the most important fraction of the total zooplankton, comprising 36.52% of all the samples. The zooplankton exhibited seasonal patterns, with the highest abundance occurring in the summer (979 ind. L^?1) and the lowest in the spring (856 ind. L^?1). Rotifera was the most abundant group in the upper and middle estuary, whereas Copepoda usually reaches the maximum densities in the higher salinity waters in the lower estuary. The study results indicated that both the sampling time (seasons) and sampling sites jointly had significant effects on the zooplankton densities (manova P < 0.05), and horizontal patterns were related to electrical conductivity, water temperature, dissolved oxygen, suspended particulate matter, pH and chlorophyll a measured in the estuary.     

The influence of moisture content on the polymer structure of polyvinyl alcohol in dispersion barrier coatings and its effect on the mass transport of oxygen

This paper presents a study of the effect of moisture on the gas permeability of polyvinyl alcohol (PVOH) and PVOH–kaolin dispersion barrier coatings. The oxygen permeability was measured at different humidity levels, and the material properties were characterized under the same conditions: polymer crystallinity, kaolin concentration, and kaolin orientation were all evaluated. The experimental results revealed that the water plasticizes the PVOH material of the coatings, and the presence of kaolin filler is unable to affect such behavior significantly. The PVOH crystallinity was affected drastically by the humidity, as water melts polymer crystallites, which is a reversible process under removal of water. The permeability data were analyzed using a thermodynamic-based model able to account for the water effect on both the solubility of the gas and the diffusivity coefficients in the polymer and composite. The results showed good agreement between the model’s predictions and the experimental data in terms of the overall permeability of the material.     

Extremely low frequency-magnetic fields (ELF-EMF) occupational exposure and natural killer activity in peripheral blood lymphocytes

Extremely Low Frequency-Magnetic Fields (ELF-MF) are possible carcinogens to humans and some data suggest that they can act as promoters or progressors. Since NK cells play a major role in the control of cancer development, an adverse effect on ELF-MF on NK function has been hypothesized. We examined NK activity in 52 workers exposed to different levels of ELF-MF in various activities. Individual exposure was monitored during 3 complete work-shifts using personal dosimeters. Environmental exposure was also monitored. ELF-MF levels in the workers were expressed as Time-Weighted Average (TWA) values. NK activity was measured in peripheral blood lymphocytes (PBL). In the whole group the median occupational TWA was 0.21 microT. According to the TWA levels, workers were classified as low exposed (26 subjects, TWA < or =0.2 microT) and higher exposed workers (26 subjects; TWA >0.2 microT). In higher exposed workers, we observed a trend to reduce NK activity compared to low exposed, but the difference was not significant. Then we selected a subgroup of highest exposed workers (12 subjects; TWA >1 microT); no difference was observed between low and highest exposed subjects in the main personal variables. Considering both E:T ratios from 12:1 to 50:1 and Lytic Units, a significant reduction in NK activity was observed in the highest exposed workers compared to the low exposed. Multivariate analysis showed a significant negative correlation between exposure and LU, while no correlation was evidenced with other personal characteristics. ELF-MF are considered possible carcinogens, and existing data suggest that they can act as promoters. Due to the role of NK activity in host defence against cancer, the results obtained in this study in workers exposed to ELF-MF levels exceeding 1 microT are in agreement with this hypothesis, and support the need for further investigation in this field.     

Side chain functional carbazole-fluorene electroactive polymers: Optical,electrochemical properties,antimicrobial activity and thin film morphologies

A new electroactive polymer based on fluorene and carbazole moieties with double bond side chain (MP25) was synthesized and then double bond at the side chain was functionalized with  COOH and  Si(OEt)₃ as ITO/glass compatible groups. Electrochemical and optical properties of the polymers were elucidated with cyclic voltammetry (CV), ultraviolet–visible absorption (UV–Vis), and photoluminescence (PL) spectroscopy. It was observed that all polymers absorbed only the UV region and emitted blue light. By using CV, HOMO values were found as approximately 5.45 eV. According to AFM results, when the rough MP25 polymer thin film was modified with ITO/glass compatible groups, more uniform and smoother polymer thin films were obtained. Thermogravimetry analyses (TGA) shown that the MP25-Si and MP25-COOH were stable against thermo-oxidative decomposition. The weight loss of MP-25-Si was found to be only %23 at 700°C. Additionally, antimicrobial activity of MP25 polymers was also investigated. According to test results, all polymers were found to have antimicrobial activity against C.albicans.     

A Multi-compound LC-MS/MS Method for the Screening of Mycotoxins in Grains

A method development and its validation are described for determining 31 selected Aspergillus, Fusarium, Penicillium, and Claviceps mycotoxins in small grain cereals (wheat, barley, oats). The method comprises an automated solvent extraction step followed by filtering, concentrating, and the analysis of the crude extract with liquid chromatographic-tandem mass spectrometric determination. The analytes included trichothecenes, zearalenone, fumonisins, moniliformin, enniatins, beauvericin, antibiotic Y, aflatoxins, ochratoxin A, mycophenolic acid, penicillic acid, and ergot alkaloids. These were separated in two consecutive chromatographic runs, both involving negative and positive electrospray ionization modes of mass spectrometry. The validation showed that the method performance was good for (semi-)quantitative work, limits of quantification varying between 1 and 1,250 μg kg⁻¹, recoveries mostly between 51% and 122%, and repeatability being from 2% to 26% within day and from 14% to 28% between days (as relative standard deviation). A distinctive suppressive matrix effect, which depended on the analyte and the matrix, was observed but could be compensated for by using matrix-assisted standards. The developed multi-mycotoxin method permits simultaneous, simple, and rapid determination of several co-existing toxins and is ideal for, e.g., screening-type work or at concentration levels relevant in animal welfare. An erratum to this article can be found at     

A computer readability formula designed for machine scoring.

Existing computer programs that measure readability are based largely upon subroutines which estimate number of syllables, usually by counting vowels. The shortcoming in estimating syllables is that it necessitates keypunching the prose into the computer. There is no need to estimate syllables since word length in letters is a better predictor of readability than word length in syllables. Therefore, a new readability formula was computed that has for its predictors letters per 100 words and sentences per 100 words. Both predictors can be counted by an optical scanning device, and thus the formula makes it economically feasible for an organization (e.g., the US Office of Education) to calibrate the readability of all textbooks for the public school system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stochastic modeling and simulation of photopolymerization process

In this study, the effect of photoinitiator concentration on the gelation time of different resins were studied in the absence of oxygen in the reaction volume by using passive microrheology technique. Four different monomers which are ethoxylated pentaerythritol tetraacrylate (SR494), trimethylolpropane triacrylate (SR351), triethylene glycol diacrylate (SR272), and 2(2‐ethoxyetoxy) ethyl acrylate (SR256) were used in these experiments. Resins were prepared from these four different monomers by mixing them with various amount of 2,2‐dimethoxy 1,2‐diphenylethanone photoinitiator molecule with high absorption coefficient at the frequency of UV light used in these experiment. The simulations of the results obtained from microrheology experiments were carried out with the new model based on the stochastic Monte Carlo approach in order to account for the inherently random and discrete nature of the photopolymerization reactions. The model captures the nonlinear decrease of gelation time with increasing photoinitator concentration and number of acrylate fragments on each monomer. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

In-line hologram reconstruction using Hartley transform

In reconstruction of in-line recorded holograms, zero-order and conjugate images appear on the same physical location as the object image. Here we propose a method, new to our knowledge, to separate the object image from the others by using two quadrature phase-shifted holograms. The method uses the Hartley transform and a phase retrieval type of algorithm on the difference hologram.     

Fenton and photo-Fenton treatment of a synthetic tannin used in leather tannery: a multi-approach study.

The aim of this work was to compare the behaviour of Fenton and photo-Fenton (UV-A, UV-C) processes to treat synthetic tannin (syntan) used in leather tannery which is one of the most polluting industries, releasing many xenobiotics. Both oxidation processes were performed at pH 3.0 and temperature 40-45 degrees C, which is the original temperature of the re-tanning process, in synthetic solutions containing 100 and 300 mg/L of COD equivalent of syntan. The efficiency of the applied oxidation processes was monitored by chemical oxygen demand (COD), oxidation redox potential (ORP) and aromaticity (UV280) and double bond (UV254) absorbance measurements. Acute toxicity test on Daphnia magna was performed to monitor toxicity in untreated and treated syntan solution. Gas chromatography-mass spectrometry (GC-MS) was applied to identify by-products of partial oxidation occurring in treated samples. The effective ratio of H2O2/FeSO4 for photo-Fenton processes was found to be feasible in terms of reagents used in the process.