THE RELATION BETWEEN BIOMARKERS AND OCCUPATIONAL EXPOSURE TO POLYCYCLIC AROMATIC COMPOUNDS

Recently a paper was published in which we reviewed a number of studies involving occupational surveys, where both the external polycyclic aromatic hydrocarbon (PAH) exposures and one or more biomarkers were quantitatively monitored. As part of that review a statistical analysis of the results of these studies was performed, which revealed that only urinary 1-hydroxypyrene (1OHPy) and possibly chromosome aberrations (CA) showed a correlation with PAH exposure, while unexpectedly, DNA adducts did not. Another observation was that although in controlled laboratory experiments good correlations have been found to occur between DNA adducts and exposure doses to polycyclic aromatic compounds (PACs), such a correlation was not found in the human occupational exposure studies reviewed. Also the analyses showed that sister chromatid exchanges (SCE) and micronuclei (MN) exhibited a very weak or an absence of a correlation, respectively, with external PAH exposure. The subject of this article is an attempt to explain: (a) why the levels of only some biomarkers correlate with PAH exposures and (b) the differences in results between controlled animal experiments and human monitoring studies.     

k-t BLAST and SENSE accelerated time-resolved three-dimensional phase contrast MRI in an intracranial aneurysm

Objective

The objective of this study was to investigate the performance of k-t BLAST (Broad-use Linear Acquisition Speed-up Technique) accelerated time-resolved 3D PC-MRI compared to SENSE (SENSitivity Encoding) acceleration in an in vitro and in vivo intracranial aneurysm.

Materials and methods

Non-accelerated, SENSE and k-t BLAST accelerated time-resolved 3D PC-MRI measurements were performed in vivo and in vitro. We analysed the consequences of various temporal resolutions in vitro.

Results

Both in vitro and in vivo measurements showed that the main effect of k-t BLAST was underestimation of velocity during systole. In the phantom, temporal blurring decreased with increasing temporal resolution. Quantification of the differences between the non-accelerated and accelerated measurements confirmed that in systole SENSE performed better than k-t BLAST in terms of mean velocity magnitude. In both in vitro and in vivo measurements, k-t BLAST had higher SNR compared to SENSE. Qualitative comparison between measurements showed good similarity.

Conclusion

Comparison with SENSE revealed temporal blurring effects in k-t BLAST accelerated measurements.     

Composite bonded systems for renovations of orthotropic steel bridge decks

The renovation solution for orthotropic steel bridge decks studied consists of bonding a second steel plate to the existing steel deck in order to reduce the stresses and increase the lifespan of the orthotropic bridge deck. A parametric study was carried out on the flexural behaviour of beams representing the renovation solution using experimental and analytical studies. The influence of different thicknesses, temperatures and spans was tested. The results obtained for the stress reduction factor show that it is independent of temperature. More efficient solutions can be achieved when minimizing the second steel plate thickness and maximizing the adhesive layer thickness reducing the weight and increasing the stiffness of the composite structure. Both elastic behaviour and yield load of the composite beams are dominated by the steel plate properties and therefore not affected significantly by temperature. However, the ultimate failure of the beams occurs by shear of the adhesive layer, the properties of which are affected by temperature.     

Habits as knowledge structures: Automaticity in goal-directed behavior.

This study tested the idea of habits as a form of goal-directed automatic behavior. Expanding on the idea that habits are mentally represented as associations between goals and actions, it was proposed that goals are capable of activating the habitual action. More specifically, when habits are established (e.g., frequent cycling to the university), the very activation of the goal to act (e.g., having to attend lectures at the university) automatically evokes the habitual response (e.g., bicycle). Indeed, it was tested and confirmed that, when behavior is habitual, behavioral responses are activated automatically. In addition, the results of 3 experiments indicated that (1) the automaticity in habits is conditional on the presence of an active goal (cf., goal-dependent automaticity; J. A. Bargh, 1989), supporting the idea that habits are mentally represented as goal—action links, and (2) the formation of implementation intentions (i.e., the creation of a strong mental link between a goal and action) may simulate goal-directed automaticity in habits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bibliometric Indicators Reflect Publication and Management Strategies

In a bibliometric study of nine research departments in the field of biotechnology and molecular biology, indicators of research capacity, output and productivity were calculated, taking into account the researchers' participation in scientific collaboration as expressed in co-publications. In a quantitative approach, rankings of departments based on a number of different research performance indicators were compared with one another. The results were discussed with members from all nine departments involved. Two publication strategies were identified, denoted as a quantity of publication and a quality of publication strategy, and two strategies with respect to scientific collaboration were outlined, one focusing on multi-lateral and a second on bi-lateral collaborations. Our findings suggest that rankings of departments may be influenced by specific publication and management strategies, which in turn may depend upon the phase of development of the departments or their personnel structure. As a consequence, differences in rankings cannot be interpreted merely in terms of quality or significance of research. It is suggested that the problem of assigning papers resulting from multi-lateral collaboration to the contributing research groups has not yet been solved properly, and that more research is needed into the influence of a department's state of development and personnel structure upon the values of bibliometric indicators. A possible implication at the science policy level is that different requirements should hold for departments of different age or personnel structure.     

水混合有机介质中木薯淀粉的羧甲基化研究

研究了水和水溶性有机物的混合物为反应介质时木薯淀粉的羧甲基化过程,探讨了影响木薯淀粉羧甲基化过程的各种因素.木薯淀粉羧甲基化反应的最佳条件为:水/异丙醇混合溶液为反应介质,水分质量分数为10%,反应温度50~55℃,淀粉质量分数为4%~8%.在这些条件下,如理论取代度DSt为2.5,木薯淀粉羧甲基化产物的取代度DS可达1.4.