Significant Decrease In Concentration Research Articles

Stability of Aflatoxins in Solution

The stability of aflatoxins B1, B2, G1, and G2 was studied in solutions containing different concentrations of water, acetonitrile, and/or methanol, and in autosampler vials treated with nitric acid or silanized. When stored at room temperature (20 degrees C) for 24 h, aflatoxins G1 and G2 were stable only in solutions containing 100% organic solvent, whereas aflatoxins B1 and B2 were stable in solutions of methanol-water and acetonitrile-water at greater than 60 and 40% organic content, respectively. At 5 degrees C, aflatoxins G1 and G2 showed a significant decrease in concentration only when kept in less than 20% aqueous organic solvent. Significant loss of aflatoxins was realized in standard, commercially available amber type I borosilicate autosampler vials, but chemical etching of the vials with nitric acid or with silanization prevented aflatoxin degradation. These results indicate that aflatoxins are unstable in aqueous solutions and that this instability can be counteracted by the presence of at least 20% organic solvent and keeping the solutions at 5 degrees C or by the use of treated vials.

Management of Changes in Liver Chemistry in MaleRats Acutely Exposed to Crude Petroleum Oil

This Study investigated the protective effect of Gongronema latifolium supplemented diet against acute hepatotoxicity induced by crude petroleum oil on male rats. Oral exposure of rats to crude petroleum significantly decreased (P<0.05) the activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD). Significant decrease in concentrations of glutathione and increase in malondialdehyde (MDA) was observed also, but catalase activity decreased nonsignificantly. Activities of these oxidative stress enzymes and concentrations of glutathione and MDA in rats exposed to crude petroleum and fed simultaneously with 20% G. latifolium supplemented diet were close to those obtained in control rats. Fluctuations in liver function parameters and serum lipid profile were observed. These results indicate that consumption of G. latifolium supplemented diet has protective effect against crude oil induced liver tissue damage.

Influence of drying treatment to electrochemically roughened Ag substrates on the corresponding surface-enhanced Raman scattering performances

For obtaining metal-island films on substrates with activity of surface-enhanced Raman scattering (SERS), a controllable and reproducible surface roughness can be easily generated by using electrochemical oxidation–reduction cycle (ORC) procedures. However, different preparation procedures could significantly change their corresponding SERS activities. In this study, SERS-active Ag substrates were prepared by using triangular-wave ORC procedures in 0.1 M KCl solutions. Before the adsorptions of probe molecules on these Ag substrates one substrate was further dried in a vacuum-dryer. Interestingly, the SERS activity of this dried Ag substrate is significantly reduced due to this additional treatment. Experimental results indicate that this phenomenon can be ascribed to the correspondingly significant decrease in content of Cl-containing complexes formed on the interface of the roughened Ag metal.

Chemical composition and starch digestibility in flours from Polish processed legume seeds

The study was undertaken to determine the effect of various treatments, i.e. cooking after soaking, freezing after cooking and storage at a low temperature (−18°C, 21days), and autoclaving, of Polish cultivars of bean, pea and lentil seeds on the chemical composition and starch digestibility of the resultant flours. The cooking of seeds caused a significant decrease in contents of ash (by 11–48%), polyphenols (by 10–70%) and protein (to 19%) in flours made of bean. In addition, analyses demonstrated significantly decreased contents of resistant starch, RS (by 61–71%) and slowly digestible starch, SDS (by 56–84%). Storage of frozen seeds resulted in insignificant changes in the chemical composition, and in increased contents of both RS and SDS. The flours produced upon the autoclaving process were characterized by similar changes in the contents of ash and protein as in cooked seeds, yet losses of polyphenols were lower and, simultaneously, contents of RS and SDS were higher. All the analyzed flours were shown to be characterized by a reduced content of amylose in starch, which might have affected its digestibility. This was indicated by a strict negative correlation reported between the value of the starch digestion index (SDRI) and amylose content of starch (r=0.84, p>0.05).

Volatile Generation in Bell Peppers during Frozen Storage and Thawing Using Selected Ion Flow Tube Mass Spectrometry (SIFT‐MS)

To determine volatile formation during storage and thawing, whole, pureed, blanched, and raw green and red bell peppers (Capsicum annuum) were frozen quickly or slowly then stored at -18 °C for up to 7 mo, with and without SnCl(2) addition during thawing. Headspace analysis was performed by a Selected Ion Flow Tube Mass Spectrometer (SIFT-MS). After blanching, (Z)-3-hexenal had a large significant decrease in concentration since it is a heat labile compound while most other volatiles did not change in concentration. The freezing process increased volatile levels in the puree only. Slow freeze peppers had higher levels of some LOX generated volatiles during storage than quick freeze. During frozen storage of blanched samples (E)-2-hexenal, (Z and E)-hexen-1-ol, and (E)-2-pentenal increased likely because of nonenzymatic autoxidation of fatty acids while other volatiles remained constant. In Raw Whole peppers, (Z)-3-hexenal, hexanal, and 2-pentylfuran were generated during storage likely because the LOX enzyme is still active during frozen storage. However, blanched samples had higher concentrations of (E)-2-hexenal, (Z and E)-hexen-1-ol, 1-penten-3-one, and (E)-2-heptenal because of enzymatic destruction of these volatiles in the raw samples. The levels of many of the volatiles in the raw samples, including (Z)-3-hexenal, (E)-2-hexenal, (Z and E)-hexen-1-ol, hexanal, (E)-2-pentenal, and 2-pentylfuran, appeared to peak around 34 d after freezing. Pureed samples had significantly higher levels of volatiles than the whole samples, and volatiles peaked earlier. Green bell pepper volatile levels were always higher than red bell pepper. Significantly higher volatile formation occurred during thawing than it did during frozen storage. Studying and monitoring the headspace volatiles with a SIFT-MS can give information that will help manufacturers better understand how the volatiles in bell peppers change during frozen storage. This will give valuable information to processors on how to minimize volatile changes during storage of frozen peppers.

Alteration in membrane tomato lipids (Solanum esculentum) induced by nitrite stress

Plants of tomato (Solanum esculentum Mill. cv. Ibiza F1) are exposed to 0.25, 1, 2.5, 5 and 10 mM NO3 - or NO2 - through rooting medium during 7 days with the aim to study KNO2 - induces changes in biomass production and membrane lipid composition. Cultivated on the same doses of KNO3 plants serve as indicators. The accumulation of NO2 - increases with external KNO2 concentrations, and is considerably higher in roots than in primary leaves. Biomass production of the growing leaves and roots is strongly depressed at higher KNO2 levels, which is associated with a significant decrease in content of total lipids and changes in fatty acid composition. Total lipids are more decreased in roots than in primary leaves. Also, significant decreases in content of global lipid fractions are recorded in elevated nitrite-stressed plants in comparison with controls. The contents of lipid components decline in all plant organs under NO2 - treatment. However, amounts of phospholipid molecules are more affected in roots than in old leaves. Moreover, in all lipid classes, levels polyunsaturated acids decrease, and that of saturated (C16:0) one increase.

Impact of sulfur dioxide on hydrogen sulfide/cystathionine-γ-lyase and hydrogen sulfide/mercaptopyruvate sulfurtransferase pathways in the pathogenesis of hypoxic pulmonary hypertension in rats

To explore the impact of sulfur dioxide (SO(2)) on hydrogen sulfide (H(2)S)/cystathionine-γ-lyase (CSE) and H(2)S/mercaptopyruvate sulfurtransferase (MPST) pathways in the pathogenesis of hypoxic pulmonary hypertension. Thirty-two male Wistar rats were randomly divided into four groups: control group (n = 8), hypoxic group (n = 8), hypoxic + SO(2) group (n = 8) and hypoxic + hydroxamate (HDX) group (n = 8). After 21 days of experiment, the concentration and production of H(2)S in lung tissues were measured respectively for each rat. The protein expression of CSE and MPST in intima and media of small pulmonary arteries in rats was detected with immunohistochemical method. Compared with control group, the mean pulmonary artery pressure (mPAP) in rats of hypoxic group was increased significantly [(33.38 ± 6.32) mm Hg vs. (16.74 ± 3.81) mm Hg, P < 0.01]. Compared with hypoxic group, the mPAP in rats of hypoxic + SO(2) group was decreased significantly [(29.65 ± 2.53) mm Hg vs. (33.38 ± 6.32) mm Hg, P < 0.01]. However, compared with hypoxic group, the mPAP in rats of hypoxic + HDX group was increased significantly [(39.44 ± 6.26) mm Hg vs. (33.38 ± 6.32) mm Hg, P < 0.01]. Compared with control group, the concentration [(2.02 ± 0.43) µmol/g vs. (3.11 ± 0.42) µmol/g, P < 0.01] and production [(19.64 ± 3.48) nmol/(g·min)vs. (28.20 ± 5.95) nmol/(g·min), P < 0.05] of H(2)S were decreased significantly in rats of hypoxic group, respectively. When treated with SO(2), hypoxic rats showed an increased concentration [(2.73 ± 0.20) µmol/g vs. (2.02 ± 0.43) µmol/g, P < 0.01] and production [(26.24 ± 1.92) nmol/(g·min) vs. (19.64 ± 3.48) nmol/(g·min), P < 0.01] of H(2)S in lung tissue compared with those without receiving SO(2) treatment. When treated with HDX, hypoxic rats showed a significant decrease in concentration [(1.64 ± 0.23) µmol/g vs. (2.02 ± 0.43) µmol/g, P < 0.05] and production [(13.94 ± 3.63) nmol/(g·min) vs. (19.64 ± 3.48) nmol/(g·min), P < 0.05] of H(2)S in lung tissue compared with those without receiving HDX treatment. As for the expression of CSE in small pulmonary arteries (SPAs), compared with control group, the expression of CSE in intima [(0.31 ± 0.02) vs. (0.36 ± 0.01), P < 0.01] and media [(0.27 ± 0.01) vs. (0.30 ± 0.01), P < 0.01] in rats of hypoxic group was decreased significantly. While compared with hypoxic group, the expression of CSE in intima [(0.35 ± 0.02) vs. (0.31 ± 0.02), P < 0.01] in SPAs of hypoxic + SO(2) group was increased significantly. With HDX treatment, the expression of CSE in intima [(0.26 ± 0.01) vs. (0.31 ± 0.02), P < 0.01] in SPAs of hypoxic group was lower than that without HDX treatment. As for the expression of MPST in SPAs, compared with hypoxic group, the expression of MPST in media [(0.32 ± 0.02) vs. (0.29 ± 0.01), P < 0.01] in SPAs of hypoxic + SO(2) group was increased significantly. SO(2) might upregulate H(2)S/CSE and H(2)S/MPST pathways in pulmonary arteries of hypoxic rats.

Impact of Reproductive Activities on the Tissues ofZonocerus variegatusGrasshopper Adults (Orthoptera: Pygomorphidae)

ABSTRACT The adult phase of insects' life is primarily for reproduction of young ones that makes continuity of life possible. The influence of reproductive activities like mating and oviposition were investigated in adult males and females variegated grasshopper, Zonocerus variegatus. The adult stage was divided into four phases according to activities performed following days of emergence, namely: early somatic phase, late somatic phase, copulation and oviposition. During each phase, the insects were dissected and the somatic tissues (haemolymph, fat body and femoral muscles) were removed analyzed for both organic and inorganic substances. The mean concentration of organic substances (protein, glucose and lipids) and inorganic substances (Na+, K+,ca2+, and Cl-) in both sexes' tissues increased significantly (p < 0.05) from early somatic to late somatic phase. However, there was a significant decrease in concentration of the metabolites in the three tissues during copulation in both sexes which further de...

A Comparison of Active Ingredients and Preservatives Between Brand Name and Generic Topical Glaucoma Medications Using Liquid Chromatography-Tandem Mass Spectrometry

Background: This work compares the concentration of active ingredients and preservatives in commonly used brand name versus generic glaucoma medications.Materials and Methods: Active ingredient and benzalkonium chloride (BAK) concentrations in brand name latanoprost and dorzolamide-timolol were each compared to two generic counterparts using liquid chromatography–mass spectrometry at baseline and after exposure to 25°C and 50°C for 30 days. Micro flow imaging was used to quantify particulate material greater than one micron in diameter.Results: Brand name formulations contained active ingredients and BAK in concentrations that were generally in agreement with their package inserts at baseline. The two generic formulations of latanoprost contained baseline levels of active ingredients that were 10% greater than their labeled value. Generic latanoprost formulations had significant loss of active ingredient concentration after exposure to 25°C and 50°C for 30 days. Both generic and brand name dorzolamide-timolol appeared relatively resistant to degradation. BAK concentrations remained stable at 25°C but decreased in some bottles at 50°C. Bottles of both generic medications had higher levels of particulate matter compared to brand name versions.Conclusions: Exposure to temperatures at the high end of the labeled value may lead to a significant decrease in concentration of active ingredients in generic formulations that could influence clinical efficacy. Re-evaluation of intraocular pressure lowering efficacy may be indicated in glaucoma patients switching from brand name to generic formulations.

Sea-spray aerosol particles generated in the surf zone

To assess the properties of aerosol particles generated over the surf zone, two experiments were held at the pier of Scripps Institution of Oceanography (SIO), La Jolla CA, and at the pier of the U.S. Army Corps of Engineers Field Research Facility (FRF) in Duck NC. On both sites concentrations of surf‐generated sea spray particles, wave parameters and meteorological conditions were measured. The surf‐aerosol concentrations in the diameter range 0.2–10 microns were obtained from the difference in aerosol size distributions measured upwind and downwind of the surf zone. It was found that the flux of surf‐generated particles at diameters at formation can be expressed in terms of wave energy dissipation, which itself is related to the properties of the incoming wavefield and the bathymetry of the beach. Although the flux can also be modeled in terms of wind speed, this relation is considered to be not universal and limited to low‐ to medium wind speeds. In Duck NC, two transport experiments were performed under offshore flow conditions. In this case, the surf‐aerosol concentrations were obtained from the differences in three aerosol size distributions, measured just before and just behind the surf zone and up to 16 km downwind (out to sea). No significant decrease in concentration was observed at the farthest range, which suggests that an appreciable amount of surf‐generated aerosols is advected over tens of kilometers.

Changes in biochemical and hematological parameters and metabolic hormones in Tsigai ewes blood in the first third of lactation

Abstract. The aim of this investigation is to determine changes in concentrations of biochemical and haematological parameters, as well as metabolic hormones in the blood of Tsigai ewes in the first third of lactation. The study included 10 ewes Tsigai breed monitored during three periods of lactation: 20 days, 40 and 60 days of lactation. Ewes were fed feed mixture (300 g/day) and meadow hay ad libitum. A significant decrease of concentrations of Ca and Na was recorded in the blood of sheep at the 40th day of lactation and later an increase at the 60th day of lactation. The opposite trend was determined for concentrations of P-inorganic. Also it was determined a significant decrease in Fe content and an increase in the concentrations of glucose, triglycerides and total protein in the first third of lactation. In the blood of ewes at 40th day of lactation it was found a significant decrease of the activity of AST and LDH in contrast to ewes at 20th day of lactation. Concentrations of T3 and T4 hormones were slightly increasing in the first third of lactation, but the differences were not significant. The blood insulin concentrations were significant increased in the first third of lactation. Haematological blood parameters in lactating ewes did not differ significantly and was within the reference values. Determining the concentration of biochemical and haematological parameters and concentrations of blood thyroid hormones and insulin in the first third of lactation are imposed as a precaution in order to better monitoring of Tsigai ewes during lactation.

Influence of Moderate, Daily Physical Activity On Body Composition and Blood Lipid Profile in Swedish Adults

Health organizations suggest that adults ought to engage in at least 30 minutes of moderate-intensity daily physical activity. This study investigated the effects of a 30-minute single daily bout of brisk walking upon risk factors for coronary heart disease with blood lipid profile in particular. Thirty-three (25-45 y) adults, were randomly assigned into an exercise group (EG; n=16, 9w) and a control group (CG; n=17, 6w). The EG walked briskly 30 minutes daily during the 3-week test period. Compliance/adherence was maximal throughout the 3-week intervention due to stringent daily monitoring. The EG showed a significant decrease in concentrations of low density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) during the intervention period. A significant inverse correlation between Δ energy expenditure/day and ΔLDL-C (r=-0.39, P<.05) and an improvement in weight and BMI in the EG was found. Average steps during 30 minutes brisk walking bout was 3669 steps/bout generating a mean energy expenditure of 191 kcal/ bout. The most unique findings were that daily single bouts of moderate-intensity physical activity for 30 minutes, during 3 weeks, induced favorable effects upon body weight, BMI, and blood concentration of LDL-C and TC in healthy adults.

The stability of rutin and chlorogenic acid during the processing of black elder(Sambucus nigra)inflorescence

Black elder inflorescence has been traditionally used in Central Europe both in folk and official medicine. This plant material is a rich source of two biologically active components, rutin and chlorogenic acid. Nevertheless, there is a lack of data on the changes of their content during processing.The stability of rutin and chlorogenic acid during drying and the long-term storage of black elder inflorescence were analysed in this study. The rutin content was determined by capillary electrophoresis using solid-phase extraction. HPLC was used for the determination of chlorogenic acid. The dependence of rutin and chlorogenic acid content on the temperature of drying and storage duration were monitored and statistically evaluated by a two-way ANOVA test. The contents of rutin and chlorogenic acid revealed no statistically significant changes when dried at temperatures of 22 °C and 30 °C. The significant decrease in contents of both studied compounds was found at a drying temperature of 50 °C. The decrease in...

Light effect on carotenoids production and expression of carotenogenesis genes in citrus callus of four genotypes

Due to their theoretically identical genetic background, citrus callus and other plant tissues may share some mechanisms in the regulation of carotenogenesis. Thus, in order to gain further information on light regulation of carotenoids biosynthesis in citrus, the carotenoids and expression profiles of carotenogenesis in calluses of four citrus genotypes treated with light or dark were investigated. As a response to white light, results showed that carotenoids biosynthesis in callus of Red Marsh grapefruit (Citrus paradisi Macf.) was hampered, whereas callus of Tarocco blood orange (C. sinensis (L.) Osbeck) was sensitive to light by accumulating over 55% more carotenoids on average. Among the detected carotenoids, the biosynthesis of carotenes seemed to be more sensitive than that of xanthophylls. Expression profiles of eight carotenogenesis genes encoding phytoene synthase (PSY), phytoene desaturase (PDS), ζ-carotene desaturase (ZDS), carotenoids isomerase (CRTISO) etc. were investigated. Results revealed that PSY was up regulated in calluses of two sweet oranges, and down regulated in callus of Murcott tangor (C. reticulata × C. sinensis). Biochemical data in the three genotypes emphasized the PSY as a rate-limiting gene in the carotenogenesis. However, in the callus of Red Marsh grapefruit, PDS and ZDS might be the rate-limiting genes, and their transcripts were apparently inhibited by light, led to significant decreases in contents of β-carotene and total carotenoids irrelevant to transcription levels of PSY. Expression of CRTISO was light-induced, especially in the callus of Murcott tangor, and increased by nearly 12-fold. In conclusion, light regulates the expression of several carotenogenesis genes in citrus callus, but may not necessarily result in significant changes in carotenoids production.

Spatial and Temporal Trends of Perfluorinated Compounds in Beluga Whales (Delphinapterus leucas) from Alaska

Wildlife from remote locations have been shown to bioaccumulate perfluorinated compounds (PFCs) in their tissues. Twelve PFCs, consisting of perfluorinated carboxylic (PFCA) and sulfonic (PFSA) acids as well as the perfluorooctane sulfonate (PFOS) precursor perfluorooctane sulfonamide (PFOSA), were measured in livers of 68 beluga whales (Delphinapterus leucas) collected from two subpopulations, Cook Inlet and eastern Chukchi Sea, in Alaska between 1989 and 2006. PFOS and PFOSA were the dominant compounds measured in both beluga stock populations, with overall median concentrations of 10.8 ng/g and 22.8 ng/g, respectively. Long-chain perfluorocarboxylates, PFCAs (9 to 14 carbons), were detected in more than 80% of the samples. Perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTriA) made up a large percentage of the PFCAs measured with median concentrations of 8.49 ng/g and 4.38 ng/g, respectively. To compare differences in location, year, sex, and length, backward stepwise multiple regression models of the individual and total PFC concentrations were used. Spatially, the Cook Inlet belugas had higher concentrations of most PFCAs and PFOS (p < 0.05); however, these belugas had a lower median concentration of PFOSA when compared to belugas from the eastern Chukchi Sea (p < 0.05). Temporal trends indicated most PFCAs, PFHxS, PFOS, and PFOSA concentrations increased from 1989 to 2006 (p < 0.05). Males had significantly higher concentrations of PFTriA, ΣPFCA, and PFOS (p < 0.05). Perfluorononanic acid (PFNA) and PFOS showed a significant decrease in concentration with increasing animal length (p < 0.05). These observations suggest the accumulation of PFCs in belugas is influenced by year, location, sex, and length.

Trefoil factor family peptides in human saliva and cyclical cervical mucus. Method evaluation and results on healthy individuals

Trefoil peptides are 7-12 kDa molecules, se-creted by a variety of mucin-producing epithelial cells from different tissues and believed to be essential for protection and maintenance of gastrointestinal mucosa. Data on concentrations of trefoil peptides in secretions are limited. We validated in-house ELISA assays, developed for measurement of trefoil peptide concentrations (TFF1, TFF2 and TFF3) in serum, for use with saliva and cervical mucus. Saliva from healthy individuals (n=30), and cervical mucus as well as blood collected three times during the menstrual cycle from healthy women (n=18) were analyzed. Recovery of all trefoil peptides in the initial supernatants of saliva and (cervical mucus) were 86 and (92)% or more. Recovery of exogenously added trefoil peptides was 93 and (95)% or more. Western blotting showed that antibodies used in the TFF3-ELISA assay recognised one molecule of the same size as TFF3 in both saliva and cervical mucus. Median concentrations of TFF1, TFF2 and TFF3 in saliva and (cervical mucus) were 2.7 (2.7), 0.08 (0.58) and 14 (430) nmol/g protein, with a significant decrease in concentrations in cervical mucus after ovulation. Serum concentrations resembled previously measured values in blood donors and showed no cyclic change. Previously established ELISA assays can be employed for measurement of trefoil peptides in saliva and cervical mucus. TFF3 was the predominant trefoil peptide in both saliva and cervical mucus, and TFF3 in cervical mucus represents the highest concentration measured in a biological fluid to date.

The effects of p53 inhibition using pifithrin-α on acute necrotizing pancreatitis in rats

To investigate the effects of p53 inhibition using pifithrin-\alpha (PFA) on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats. The role of p53 during acute pancreatitis is unclear. Materials and methods: Rats were divided into 4 groups, 2 of which were initially given only saline (the sham group) and 2 of which were given glycodeoxycholic acid in order to induce ANP. Each group was then identified according to treatment plan: sham+saline, sham+PFA, ANP+saline, or ANP+PFA. The study then investigated the extent of acinar cell injury, apoptosis, mortality, systemic cardiorespiratory variables, functional capillary density (FCD), renal/hepatic functions, and changes in some enzyme markers for pancreatic and lung tissue during ANP in rats. Results: The induction of ANP resulted in a significant increase in mortality rate, pancreatic necrosis, apoptosis, serum activity of amylase, alanine aminotransferase (ALT), interleukin (IL)-6, lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid, serum concentration of urea, and tissue activity of myeloperoxidase (MPO) and malondialdehyde (MDA) in the pancreas and lung. In addition, ANP induction caused a significant decrease in concentrations of calcium, blood pressure, urine output, pO2, and functional capillary density (FCD). The use of PFA did not alter these changes. Conclusion: PFA demonstrated no effect on the course of ANP in rats. Therefore, it has no value in the treatment of acute pancreatitis.

Zero-valent iron nanoparticles in treatment of acid mine water from in situ uranium leaching

Acid mine water from in situ chemical leaching of uranium (Straz pod Ralskem, Czech Republic) was treated in laboratory scale experiments by zero-valent iron nanoparticles (nZVI). For the first time, nZVI were applied for the treatment of the real acid water system containing the miscellaneous mixture of pollutants, where the various removal mechanisms occur simultaneously. Toxicity of the treated saline acid water is caused by major contaminants represented by aluminum and sulphates in a high concentration, as well as by microcontaminants like As, Be, Cd, Cr, Cu, Ni, U, V, and Zn. Laboratory batch experiments proved a significant decrease in concentrations of all the monitored pollutants due to an increase in pH and a decrease in oxidation–reduction potential related to an application of nZVI. The assumed mechanisms of contaminants removal include precipitation of cations in a lower oxidation state, precipitation caused by a simple pH increase and co-precipitation with the formed iron oxyhydroxides. The possibility to control the reaction kinetics through the nature of the surface stabilizing shell (polymer vs. FeO nanolayer) is discussed as an important practical aspect.

A New Method to Quantify the Application Thickness of Sunscreen on Skin

Proper application of sunscreen is essential as an effective public health strategy for skin cancer prevention. Insufficient application is common among sunbathers, results in decreased sun protection and may therefore lead to increased UV damage of the skin. However, no objective measure of sunscreen application thickness (SAT) is currently available for field-based use. We present a method to detect SAT on human skin for determining the amount of sunscreen applied and thus enabling comparisons to manufacturer recommendations. Using a skin swabbing method and subsequent spectrophotometric analysis, we were able to determine SAT on human skin. A swabbing method was used to derive SAT on skin (in mg sunscreen per cm(2) of skin area) through the concentration-absorption relationship of sunscreen determined in laboratory experiments. Analysis differentiated SATs between 0.25 and 4 mg cm(-2) and showed a small but significant decrease in concentration over time postapplication. A field study was performed, in which the heterogeneity of sunscreen application could be investigated. The proposed method is a low cost, noninvasive method for the determination of SAT on skin and it can be used as a valid tool in field- and population-based studies.

Contrasting time trends of organic contaminants in Antarctic pelagic and benthic food webs

We demonstrate that pelagic Antarctic seabirds show significant decreases in concentrations of some persistent organic pollutants. Trends in Adélie penguins and Southern fulmars fit in a general pattern revealed by a broad literature review. Downward trends are also visible in pelagic fish, contrasting sharply with steady or increasing concentrations in Antarctic benthic organisms. Transfer of contaminants between Antarctic pelagic and benthic food webs is associated with seasonal sea-ice dynamics which may influence the balance between the final receptors of contaminants under different climatic conditions. This complicates the predictability of future trends of emerging compounds in the Antarctic ecosystem, such as of the brominated compounds that we detected in Antarctic petrels. The discrepancy in trends between pelagic and benthic organisms shows that Antarctic biota are still final receptors of globally released organic contaminants and it remains questionable whether the total environmental burden of contaminants in the Antarctic ecosystem is declining.