Contaminants in ospreys from the Pacific Northwest: I. Trends and patterns in polychlorinated dibenzo-p-dioxins and -dibenzofurans in eggs and plasma

Osprey (Pandion haliaetus) eggs were collected from 1991 to 1997 at nests (n = 121) upstream and downstream of bleached kraft pulp mills and at reference sites in the Fraser and Columbia River drainage systems of British Columbia, Washington, and Oregon. Blood samples were collected from nestling ospreys during the 1992 breeding season on the Thompson River. Samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and -dibenzofurans (PCDFs). Mean concentrations of 2,3,7,8-TCDD were significantly higher in eggs collected in 1991 at downstream compared to upstream nests near pulp mills at Kamloops and Castlegar, British Columbia. There were no significant temporal trends in 2,3,7,8-TCDD, -TCDF or other measured compounds at a sample of nests monitored between 1991 and 1994 downstream of the Castlegar pulp mill, despite changes in bleaching technology (CIO2 substitution). However, by 1997 concentrations of 2, 3,7,8-TCDD and -TCDF were significantly lower than previous years in nests sampled downstream at both Castlegar and Kamloops. An unusual pattern of higher chlorinated PCDDs and PCDFs was found in many of the osprey eggs collected in this study, and considerable individual variation in the pattern existed among eggs from the same site. For example, eggs from four different nests at one study area (Quesnel) on the Fraser River had concentrations of 1,2,3,4,6,7,8-HpCDD ranging from <1 to 1,100 ng/kg and OCDD from <1 to 7,000 ng/kg wet weight. Higher mean concentrations of HpCDD and OCDD were found in eggs from the Thompson River, a tributary of the Fraser, compared to the Columbia River, and concentrations were generally higher at nests upstream of pulp mills. In plasma samples, 1,2,3,4,6,7,8-HpCDD and OCDD were the main compounds detected, with no significant differences measured between samples upstream versus downstream or earlier versus later in the breeding season. Use of chlorophenolic wood preservatives by lumber processors was considered the main source of higher chlorinated PCDD/Fs throughout the systems, based on patterns of trace PCDFs in eggs and significant correlations between egg concentrations of pentachlorophenol and both HpCDD (r = 0.891, p < 0.01) and OCDD (r = 0.870, p < 0.01).     

Cellular basis of biventricular hypertrophy and arrhythmogenesis in dogs with chronic complete atrioventricular block and acquired torsade de pointes

OBJECTIVE: To estimate the performance of currently available tests in detecting ovarian cancer in asymptomatic women. METHODS: Systematic review of prospective screening studies. RESULTS: Twenty-five studies were identified: sixteen studied women at average risk and nine studied women at higher risk. Most studies evaluated only one screening method, were small, detecting few cancers, and gave few follow up details. Sensitivity estimates are therefore imprecise. In a typical larger study, reported sensitivity of ultrasound screening at one year was around 100% (95% CI 54%-100%), while the sensitivity of CA125 measurement followed by ultrasound (multimodal screening) was about 80% (95% CI 49%-95%). False positive rates ranged between 1.2% and 2.5% for grey scale ultrasound, between 0.3% and 0.7% for ultrasound with colour Doppler and between 0.1% and 0.6% for multimodal screening. This implies that, in annual screening of a population with an incidence of 40 per 100,000, and if no cancers were missed, between 2.5 and 60 women would undergo surgery for every primary ovarian cancer detected. CONCLUSIONS: Ultrasound and multimodal screening can detect ovarian cancer in asymptomatic women, but there is currently no evidence on whether screening improves outcome for women in any risk group. On-going randomised controlled trials should establish the magnitude of any benefit of screening. The low prevalence of ovarian cancer in the population, and its rate of progression, may limit the potential cost-effectiveness of screening.     

Changes in self-schema structure in cognitive therapy for major depressive disorder: A randomized clinical trial.

Negative cognitive structure (particularly for interpersonal content) has been shown in some research to persist past a current episode of depression and potentially to be a stable marker of vulnerability for depression (D. J. A. Dozois, 2007; D. J. A. Dozois & K. S. Dobson, 2001a). Given that cognitive therapy (CT) is highly effective for treating the acute phase of a depressive episode and that this treatment also reduces the risk of relapse and recurrence, it is possible that CT may alter these stable cognitive structures. In the current study, patients were randomly assigned to CT+ pharmacotherapy (n = 21) or to pharmacotherapy alone (n = 21). Both groups evidenced significant and similar reductions in level of depression (as measured with the Beck Depression Inventory–II and the Hamilton Rating Scale for Depression), as well as automatic thoughts and dysfunctional attitudes. However, group differences were found on cognitive organization in favor of individuals who received the combination of CT+ pharmacotherapy. The implications of these results for understanding mechanisms of change in therapy and the prophylactic nature of CT are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determination of vitamin A in liver and liver-containing products using narrow-bore normal, phase HPLC

Vitamin A concentrations in livers of fattening animals and liver-containing products may reach much higher values than was assumed up to now. This effect may be caused by animal feed, which is usually supplemented with vitamins. To support this supposition, 57 liver samples of different species of animals, 97 liver sausages and 106 samples of liver-containing infant food were analysed. For isolation of retinol from the sample matrix the sample was saponified for 16 h under a nitrogen atmosphere at room temperature. Retinol was extracted from the saponification solution by using disposable cartridges. For Chromatographic determination a normalphase HPLC system using a narrow-bore analytical column and a photodiode array detector was used. It was possible to separate all-trans-retinol from other isomers. The identity of the peaks could be confirmed by recording the UV spectra. —The results of the retinol contents found in the analysed samples ranged from 11.6 to 160.7 mg/100 g in liver, from 1.4 to 31.1 mg/100 g in liver sausages and from 0.5 to 3.8 mg/100 g in infant food containing between 5 and 11% liver. By consuming liver-containing meals frequently a multiple amount of the recommended dietary intake ranging from 0.375 mg for infants to 0.8 mg for adults may be taken up. Also the recommended daily intakes of the Deutsche Gesellschaft für Ernährung can be exceeded. —The carry-over effect of daily vitamin A consumption of pigs and their liver vitamin A was investigated by parallel determination of the retinol content in the liver after slaughtering and the vitamin A content in the pig-feed during the fattening period. A clear correlation between their daily vitamin A intake and the resulting retinol content in the livers was found.

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Vitamin-A-Bestimmung in Leber und leberhaltigen Lebensmitteln unter Anwendung von Narrow-Bore-Normalphasen-HPLC

Zusammenfassung Die Vitamin-A-Gehalte in Lebern von Schlachttieren können höhere Werte annehmen als man bisher vermutete, u. a.,weil in der Tiermast verwendete Futtermittel mit Vitaminen supplementiert werden. Um den aktuellen Status aufzuzeigen, wurden 57 Leberproben unterschiedlicher Tierarten, 97 Leberwürste und 106 Gläschen vorgefertigter Kleinkindernahrung mit Lebergehalten zwischen 5 und 11% untersucht. Die Proben wurden kalt unter Stickstoffatmosphäre verseift und das Unverseifbare mit Hilfe von Kieselgurkartuschen extrahiert. Zur chromatographischen Bestimmung wurde ein Normalphasen-HPLC-System mit einer Narrow-Bore-Säule verwendet. Detektiert wurde mit einem Photodiodenarray-Detektor. Das all-trans-Retinol konnte von anderen Isomeren getrennt werden. Die gefundenen Retinolkonzentrationen bewegten sich in Bereichen zwischen 11,6 und 160,7 mg/100 g in Leber, zwischen 1,4 und 31,1 mg/100 g in Leberwurst und zwischen 0,5 und 3,8 mg/100 g in Kindernahrung. Bei häufigem Konsum von leberhaltigen Mahlzeiten kann ein Vielfaches des RDI (Recommended dietary intake), der zwischen 0,375 mg für Kleinkinder und 0,8 mg für Heranwachsende liegt, bzw. der von der DGE empfohlenen täglichen Zufuhr, die sich zwischen 0,5 und 1,1 mg bewegt, an Vitamin A zugeführt werden. —Der Zusammenhang zwischen dem täglich aufgenommenen Vitamin A von Mastschweinen und dem Retinol-Gehalt in ihren Lebern wurde untersucht. Hierzu wurde sowohl der Vitamin-A-Gehalt der Schweinelebern nach Schlachtung der Tiere als auch der Gehalt in den Futtermitteln, mit denen sie während der Mastperiode gefüttert wurden, untersucht. Eine deutliche Korrelation wurde festgestellt.

     

Touch‐typing for better spelling and narrative‐writing skills on the computer

This study investigated the effect of a touch‐typing course on the spelling and narrative‐writing skills on the computer of elementary school students. Data of 207 students in Grades 4, 5, and 6 were analysed using a pretest–posttest design. Students in the experimental group (n = 154) followed a touch‐typing course, and those in the control group (n = 53) did not. The experimental group showed more progress in typing, spelling, and narrative‐writing skills on the computer than the control group. It can be concluded that the touch‐typing course had a positive effect, not only on typing skills but also on spelling and narrative‐writing skills on the computer.     

Intercalating Electron Dyes for TEM Visualization of DNA at the Single-Molecule Level

Staining compounds containing heavy elements (electron dyes) can facilitate the visualization of DNA and related biomolecules by using TEM. However, research into the synthesis and utilization of alternative electron dyes has been limited. Here, we report the synthesis of a novel DNA intercalator molecule, bis-acridine uranyl (BAU). NMR spectroscopy and MS confirmed the validity of the synthetic strategy and gel electrophoresis verified the binding of BAU to DNA. For TEM imaging of DNA, two-dimensional DNA origami nanostructures were used as a robust microscopy test object. By using scanning transmission electron microscopy (STEM) imaging, which is favored over conventional wide-field TEM for improved contrast, and therefore, quantitative image analysis, it is found that the synthesized BAU intercalator can render DNA visible, even at the single-molecule scale. For comparison, other staining compounds with a purported affinity towards DNA, such as dichloroplatinum, cisplatin, osmium tetroxide, and uranyl acetate, have been evaluated. The STEM contrast is discussed in terms of the DNA–dye association constants, number of dye molecules bound per base pair, and the electron-scattering capacity of the metal-containing ligands. These findings pave the way for the future development of electron dyes with specific DNA-binding motifs for high-resolution TEM imaging.     

Removal of two waterborne pathogenic bacterial strains by activated carbon particles prior to and after charge modification

Waterborne diseases constitute a threat to public health despite costly treatment measures aimed at removing pathogenic microorganisms from potable water supplies. This paper compared the removal of Raoultella terrigena ATCC 33257 and Escherichia coli ATCC 25922 by negatively and positively charged types of activated carbon particles. Both strains display bimodal negative zeta-potential distributions in stabilized water. Carbon particles were suspended to an equivalent external geometric surface area of 700 cm2 in 250 mL of a bacterial suspension, with shaking. Samples were taken after different durations for plate counting. Initial removal rates were less elevated for the positively charged carbon particle than expected, yielding the conclusion that bacterial adhesion under shaking is mass-transport limited. After 360 min, however, the log-reduction of the more negatively charged R. terrigena in suspension was largest for the positively charged carbon particles as compared with the negatively charged ones, although conditioning in ultrapure or tap water of positively charged carbon particles for 21 days eliminated the favorable effect of the positive charge due to counterion adsorption from the water. Removal of the less negatively charged E. coli was less affected by aging of the (positively charged) carbon particles, confirming the role of electrostatic interactions in bacterial removal by activated carbon particles. The microporous, negatively charged coconut carbon performed less than the mesoporous, positively charged carbon particle prior to conditioning but did not suffer from loss of effect after conditioning in ultrapure or tap water.     

Sculpting nanoelectrodes with a transmission electron beam for electrical and geometrical characterization of nanoparticles

A method to produce metal electrodes with a gap of a few nanometers with a highly focused electron beam in a transmission electron microscope (TEM) is described. With this method the electrical and geometrical characterization of the same particle is possible. The I-V characteristics of a gold particle trapped between such electrodes showed the expected single-electron tunneling behavior, with a Coulomb gap corresponding to the geometry of the particle as observed with high-resolution TEM.     

Constructing invariants for hybrid systems

We present a new method for generating algebraic invariants of hybrid systems. The method reduces the invariant generation problem to a constraint solving problem using techniques from the theory of ideals over polynomial rings. Starting with a template invariant—a polynomial equality over the system variables with unknown coefficients—constraints are generated on the coefficients guaranteeing that the solutions are inductive invariants. To control the complexity of the constraint solving, several stronger conditions that imply inductiveness are proposed, thus allowing a trade-off between the complexity of the invariant generation process and the strength of the resulting invariants. This research was supported in part by NSF grants CCR-01-21403, CCR-02-20134 and CCR-02-09237, by ARO grant DAAD19-01-1-0723, by ARPA/AF contracts F33615-00-C-1693 and F33615-99-C-3014, and by NAVY/ONR contract N00014-03-1-0939.