Analysis of very low bacterial counts in small sample volumes using angle-resolved light scattering.

Because of its high sensitivity to even small objects and the quick measurement principle, angle-resolved scattering (ARS) measurements exhibit a promising potential as a rapid analysis tool for bacterial cells at small sample sizes and very low numbers of cells. In this study, investigations on scattered light from various bacterial cell samples revealed applicability down to single cell levels, which is a huge benefit compared to conventional methods that depend on time-consuming cellular growth over several hours or even days. With the proposed setup and data analysis method, it is possible to detect scatter differences among cell types, together with the cell concentration.

Embodied markedness of parity? Examining handedness effects on parity judgments.

Parity is important semantic information encoded by numbers. Interestingly, there are hand-based effects in parity judgment tasks: right-hand responses are faster for even and left-hand responses for odd numbers. As this effect was initially explained by the markedness of the words even vs. odd and right vs. left, it was denoted as the linguistic markedness of response codes (MARC) effect. In the present study, we investigated whether the MARC effect differs for right and left handers. We conducted a parity judgment task, in which right- and left-handed participants had to decide whether a presented single or two-digit number was odd or even by pressing a corresponding response key. We found that handedness modulated the MARC effect for unit digits. While we replicated a regular MARC effect for right handers, there was no evidence for a MARC effect for left handers. However, closer inspection revealed that the MARC effect in left handers depended on the degree of left-handedness with a reversed MARC effect for most left-handed participants. Furthermore, although parity of tens digits interfered with the processing of unit digits, the MARC effect for tens digits was not modulated by handedness. Our findings are discussed in the light of three different accounts for the MARC effect: the linguistic markedness account, the polarity correspondence principle, and the body-specificity hypothesis.

Late infiltration of post-orthodontic white spot lesions.

White spot lesion (WSL) infiltration has been recommended immediately after debonding of orthodontic brackets. It is however not clear if established inactive WSLs can also be masked through infiltration. Orthodontic treatment of a 19-year-old patient had to be terminated prematurely due to development of multiple WSLs of varying severity. Three months after debonding, the patient presented for lesion infiltration. After etching with 15% HCl gel and re-wetting of the dried surfaces it seemed that a good outcome could be expected. Lesion infiltration led to complete masking of less severe WSLs. The visual appearance of moderate and severe WSLs was improved but they were still visible after treatment. Inactive WSLs may not represent an increased caries risk, but patients are often bothered esthetically. Infiltration by repeated etching might be a viable approach even for inactive WSLs. Controlled clinical trials are needed to investigate the long-term performance of this technique.

[German version of the math anxiety questionnaire (FRA) for 6- to 9-year-old children]. / Deutschsprachige Version des Fragebogens für Rechenangst (FRA) für 6- bis 9-jährige Kinder.

OBJECTIVES: Is the FRA a reliable and valid instrument? Are there any gender differences concerning math anxiety? Are there any developmental changes in this regard in the course of the early grades? METHODS: Together with the dyscalculia test TEDI-MATH, the FRA was presented to a total of 450 children from the first to the third grade of primary school (at least 40 girls and 40 boys per semester). RESULTS: The total scale has an internal consistency (Cronbach's alpha) between 0.83 and 0.91. Correlations between arithmetic skills and the FRA scales were mostly significant. The significantly higher negative scores for girls were taken into account by providing standard scores corrected for gender. No systematic developmental changes could be observed. CONCLUSIONS: The FRA is the first German math anxiety questionnaire for primary school children. High reliability, standard scores corrected for gender, and economic handling make it an instrument well suited for use in clinical settings (e.g., dyscalculia diagnostics and intervention).