261 research outputs found

    Occurrence and profiles of PCBs and PBDEs in harbour seals and harbour porpoises from the southern North Sea

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    Harbour porpoises (Phocoena phocoen) and harbour seals (Phoca vitulina), two representative top coastal pollution. Concentrations of sum PCBs were 1-2 orders of magnitude higher than concentrations of sum PBDEs (with median values of 23.1 ÎĽg.g- lw (lipid weight) and 12.4 ÎĽ.g-1 lw for sum PCBs and 0.33 ÎĽ.g- lw and 0.76 ÎĽ.g-1 lw for sum PBDEs in harbour seals and harbour porpoises respectively) and were highly dependent of age group and gender. For both species, the highest PCB concentrations were observed in adult males as the result of accumulation for years and years, while the highest PBDE concentrations were measured in juveniles probably due to better developed metabolic capacities for these congeners with age in adults. Results for PCBs were higher than observations in harbour seals and porpoises from other areas, while results for PBDEs were comparable indicating that the North Sea is a highly contaminated area. Relative PCB and PBDE profiles were constructed to compare metabolic capacities between harbour seals and porpoises. A higher contribution of lower chlorinated and nonpersistent congeners, such as CB 52, CB 95, CB 101, CB 118 and CB 149 indicated that harbour porpoises are unable to metabolize these compounds. Similar to PCBs, higher contributions of other PBDEs than BDE 47 were observed in harbour porpoises, suggesting that this species has difficulties to metabolize these congeners. In contrast, harbour seals showed a higher ability to metabolize PCBs and PBDEs

    Mission moves

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    This scholarly book is the final result of a team-research project, done by ten Practical Theologians from three denominations in the Reformed tradition in South Africa. The authors posed the following research problem and-question: What would be the relationship (if any) between preaching (and the liturgy of which it is a part) and the development of missional congregations? And secondly, what kind of preaching and preacher would best serve (even facilitate) such a process of missional congregational development in preaching and worship

    Mission moves

    Get PDF
    This scholarly book is the final result of a team-research project, done by ten Practical Theologians from three denominations in the Reformed tradition in South Africa. The authors posed the following research problem and-question: What would be the relationship (if any) between preaching (and the liturgy of which it is a part) and the development of missional congregations? And secondly, what kind of preaching and preacher would best serve (even facilitate) such a process of missional congregational development in preaching and worship

    Electromagnetic levitation containerless processing of metallic materials in microgravity: thermophysical properties

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    Transitions from the liquid to the solid state of matter are omnipresent. They form a crucial step in the industrial solidification of metallic alloy melts and are greatly influenced by the thermophysical properties of the melt. Knowledge of the thermophysical properties of liquid metallic alloys is necessary in order to gain a tight control over the solidification pathway, and over the obtained material structure of the solid. Measurements of thermophysical properties on ground are often difficult, or even impossible, since liquids are strongly influenced by earth’s gravity. Another problem is the reactivity of melts with container materials, especially at high temperature. Finally, deep undercooling, necessary to understand nucleus formation and equilibrium as well as nonequilibrium solidification, can only be achieved in a containerless environment. Containerless experiments in microgravity allow precise benchmark measurements of thermophysical properties. The electromagnetic levitator ISS-EML on the International Space Station (ISS) offers perfect conditions for such experiments. This way, data for process simulations is obtained, and a deeper understanding of nucleation, crystal growth, microstructural evolution, and other details of the transformation from liquid to solid can be gained. Here, we address the scientific questions in detail, show highlights of recent achievements, and give an outlook on future work

    New approach for time-resolved and dynamic investigations on nanoparticles agglomeration

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    Nanoparticle (NP) colloidal stability plays a crucial role in biomedical application not only for human and environmental safety but also for NP efficiency and functionality. NP agglomeration is considered as a possible process in monodispersed NP colloidal solutions, which drastically affects colloidal stability. This process is triggered by changes in the physicochemical properties of the surrounding media, such as ionic strength (IS), pH value, or presence of biomolecules. Despite different available characterization methods for nanoparticles (NPs), there is a lack of information about the underlying mechanisms at the early stage of dynamic behaviors, namely changing in NP size distribution and structure while placing them from a stable colloidal solution to a new media like biological fluids. In this study, an advanced in situ approach is presented that combines small angle X-ray scattering (SAXS) and microfluidics, allowing label-free, direct, time-resolved, and dynamic observations of the early stage of NP interaction/agglomeration initiated by environmental changes. It is shown for silica NPs that the presence of protein in the media enormously accelerates the NP agglomeration process compared to respective changes in IS and pH. High IS results in a staring agglomeration process after 40 min, though, in case of protein presence in media, this time decreased enormously to 48 s. These time scales show that this method is sensitive and precise in depicting the dynamics of fast and slow NP interactions in colloidal conditions and therefore supports understanding the colloidal stability of NPs in various media concluding in safe and efficient NP designing for various applications

    An endometrial histomorphometric study of CD56+ natural killer cells in women with unexplained infertility

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    BACKGROUND. The number of peripheral blood and endometrial natural killer cells varies greatly during implantation and the first trimester of pregnancy and is thought to play a role in the maintenance of a healthy pregnancy. However, the role of endometrial CD56+ natural killer (NK) cells as an immunological mechanism in unexplained infertility is yet unknown. OBJECTIVES. The study aimed to enumerate the concentrations of CD56+ NK cells in endometrial samples, and to statistically compare these numbers between fertile and infertile women. METHODS. A histomorphometric analysis was conducted using haematoxylin and eosin staining and an immunohistochemical approach was used for quantifying cell numbers. RESULTS. Fifty samples were collected in equal parts between a study group of infertile female subjects (mean (standard deviation) age 35 (4), range 26 - 42 years) and a control group of multiparous fertile individuals (mean (SD) age 43.4 (6.3), range 30 - 55). The mean number of CD56+ NK cells present at different depths for both the study and control groups did not differ significantly. Age and group (study or control) were not significantly related to the mean number of CD56+ NK cells. However, for the late secretory phase the mean number of CD56+ NK cells was significantly higher than for the early phase. CONCLUSION. Our findings could not identify a statistically significant correlation between the number of CD56+ NK cells and infertility.Discovery Foundation Research Awardshttp://sajog.org.za/index.php/SAJOGhttp://www.journals.co.za/content/journalam2017Anatomical PathologyAnatomyHaematologyImmunologyStatistic

    Measuring serotonin synthesis: from conventional methods to PET tracers and their (pre)clinical implications

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    The serotonergic system of the brain is complex, with an extensive innervation pattern covering all brain regions and endowed with at least 15 different receptors (each with their particular distribution patterns), specific reuptake mechanisms and synthetic processes. Many aspects of the functioning of the serotonergic system are still unclear, partially because of the difficulty of measuring physiological processes in the living brain. In this review we give an overview of the conventional methods of measuring serotonin synthesis and methods using positron emission tomography (PET) tracers, more specifically with respect to serotonergic function in affective disorders. Conventional methods are invasive and do not directly measure synthesis rates. Although they may give insight into turnover rates, a more direct measurement may be preferred. PET is a noninvasive technique which can trace metabolic processes, like serotonin synthesis. Tracers developed for this purpose are α-[11C]methyltryptophan ([11C]AMT) and 5-hydroxy-L-[β-11C]tryptophan ([11C]5-HTP). Both tracers have advantages and disadvantages. [11C]AMT can enter the kynurenine pathway under inflammatory conditions (and thus provide a false signal), but this tracer has been used in many studies leading to novel insights regarding antidepressant action. [11C]5-HTP is difficult to produce, but trapping of this compound may better represent serotonin synthesis. AMT and 5-HTP kinetics are differently affected by tryptophan depletion and changes of mood. This may indicate that both tracers are associated with different enzymatic processes. In conclusion, PET with radiolabelled substrates for the serotonergic pathway is the only direct way to detect changes of serotonin synthesis in the living brain

    Adipose Inflammation Initiates Recruitment of Leukocytes to Mouse Femoral Artery: Role of Adipo-Vascular Axis in Chronic Inflammation

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    Background: Although inflammation within adipose tissues is known to play a role in metabolic syndrome, the causative connection between inflamed adipose tissue and atherosclerosis is not fully understood. In the present study, we examined the direct effects of adipose tissue on macro-vascular inflammation using intravital microscopic analysis of the femoral artery after adipose tissue transplantation. Methods and Results: We obtained subcutaneous (SQ) and visceral (VIS) adipose tissues from C57BL/6 mice fed normal chow (NC) or a high fat diet (HF), then transplanted the tissues into the perivascular area of the femoral artery of recipient C57/BL6 mice. Quantitative intravital microscopic analysis revealed an increase in adherent leukocytes after adipose tissue transplantation, with VIS found to induce significantly more leukocyte accumulation as compared to SQ. Moreover, adipose tissues from HF fed mice showed significantly more adhesion to the femoral artery. Simultaneous flow cytometry demonstrated upregulation of CD11b on peripheral granulocyte and monocytes after adipose tissue transplantation. We also observed dominant expressions of the inflammatory cytokine IL-6, and chemokines MCP-1 and MIP-1b in the stromal vascular fraction (SVF) of these adipose tissues as well as sera of recipient mice after transplantation. Finally, massive accumulations of pro-inflammatory and dendritic cells were detected in mice with VIS transplantation as compared to SQ, as well as in HF mice as compared to those fed NC
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