Label-free electronic probing of nucleic acids and proteins at the nanoscale using the nanoneedle biosensor

Detection of proteins and nucleic acids is dominantly performed using optical fluorescence based techniques, which are more costly and timely than electrical detection due to the need for expensive and bulky optical equipment and the process of fluorescent tagging. In this paper, we discuss our study of the electrical properties of nucleic acids and proteins at the nanoscale using a nanoelectronic probe we have developed, which we refer to as the Nanoneedle biosensor. The nanoneedle consists of four thin film layers: a conductive layer at the bottom acting as an electrode, an oxide layer on top, and another conductive layer on top of that, with a protective oxide above. The presence of proteins and nucleic acids near the tip results in a decrease in impedance across the sensing electrodes. There are three basic mechanisms behind the electrical response of DNA and protein molecules in solution under an applied alternating electrical field. The first change stems from modulation of the relative permittivity at the interface. The second mechanism is the formation and relaxation of the induced dipole moment. The third mechanism is the tunneling of electrons through the biomolecules. The results presented in this paper can be extended to develop low cost point-of-care diagnostic assays for the clinical setting.     

The effect of rowing headgear on forced convective heat loss and radiant heat gain on a thermal manikin headform

Abstract

Both radiant and forced convective heat flow were measured for a prototype rowing headgear and white and black cotton caps. The measurements were performed on a thermal manikin headform at a wind speed of 4.0 m · s^?1 (s = 0.1) in a climate chamber at 22.0°C (s = 0.05), with and without radiant heat flow from a heat lamp, coming from either directly above (90°) or from above at an angle of 55°. The effects of hair were studied by repeating selected measurements with a wig. All headgear reduced the radiant heat gain compared with the nude headform: about 80% for the caps and 95% for the prototype rowing headgear (P < 0.01). Forced convective heat loss was reduced more by the caps (36%) than by the prototype rowing headgear (9%) (P < 0.01). The radiant heat gain contributed maximally 13% to the net heat transfer, with or without headgear, showing that forced convective heat loss is the dominant heat transfer parameter under the chosen conditions. The results of the headgear – wig combinations were qualitatively similar, with lower absolute heat transfer.     

The effects of task constraints on the organization of interception movements

In the light of the intensity coupling effects reported in the literature, subjects' capacities for independently controlling the absolute velocity of their movement at the point of interception was evaluated by asking them to learn to propel orthogonally approaching balls, varying in their speed of approach, into target boxes placed at various distances from the interception point. As required for successful accomplishment of the task, movement velocity was found to be adapted to the distance to be covered, with the near target giving rise to lower velocities and the far target giving rise to higher velocities even when the conditions were presented in random order. Nevertheless, even though target distance accounted for a substantial proportion of the total variance, a small but significant effect of ball approach speed on movement velocity was found, suggesting that intensity coupling is a persistent but modulable phenomenon in interception tasks.     

Testing Social-Cognitive Theory to Explain Physical Activity Change in Adolescent Girls From Low-Income Communities

Purpose

The aim of this study was to test the hypothesized structural paths in Bandura's social-cognitive theory (SCT) model on adolescent girls' physical activity following a 12-month physical activity and dietary intervention to prevent obesity.

Method

We conducted a 12-month follow-up study of 235 adolescent girls (M _age = 13.2 years, SD = 0.4) from 12 secondary schools located in low-income communities. At baseline, participants completed SCT scales related to physical activity (i.e., self-efficacy, intention, parental support, and outcome expectations). At baseline and 12-month follow-up (postintervention), participants wore accelerometers for 7 days. Structural equation modeling was used to determine if Time 1 measures predicted physical activity at 12-month follow-up after adjusting for baseline activity.

Results

The model explained 28% and 34% of the variance in physical activity and intention, respectively. Model fit indexes indicated the data were a good fit to the model; however, only self-efficacy was associated with physical activity at 12 months. There was no support for intention or outcome expectations as proximal determinants of behavior. Self-efficacy was associated with outcome expectations and parental support; however, only outcome expectations predicted intention.

Conclusions

Current findings indicate a large proportion of the variance for physical activity and intention remains unexplained and that the proposed pathways in the SCT model were not fully supported. Future model testing may need to consider augmentation or integration of theoretical models, which may include ecological components if we are to advance our understanding of physical activity behavior in this subgroup of the adolescent population.     

Anaphylaxis and generalized urticaria from eating Chinese bayberry fruit

Chinese bayberry Myrica rubra is a very popular fruit in southeastern China. In spite of its wide consumption, no allergies to this fruit have been reported previously. Here we report on a 40-year-old woman suffering from anaphylaxis to Chinese bayberry fruit. Prick-prick skin tests revealed strong reactions to fresh Chinese bayberry fruits as well as to peach, and weaker reactions to some other fruits including apple, melon, and banana. ImmunoCAP analysis revealed identical titers of specific IgE (4.3 kU_A/L) to peach extract and its lipid transfer protein (LTP, rPru p 3), which was confirmed by detection of a 9 kD band following immunoblotting. Immunoblot analysis with Chinese bayberry extract gave bands of 22, 45, and 90 kD, but no 9 kD band was recognized. There was also no evidence of LTP recognition for loquat (36 kD) or melon (24 kD). This first report of a severe allergic reaction to Chinese bayberry fruit in a patient with LTP-mediated peach allergy indicates that other as yet unidentified non-pollen related fruit allergens are involved in this new severe fruit allergy.     

A longitudinal study of conceptual change: Preservice elementary teachers' conceptions of moon phases

This research consists of a longitudinal study of 12 female elementary preservice teachers' conceptual understanding over the course of several months. The context in which the participants received instruction was in an inquiry‐based physics course, and the targeted science content was the cause of moon phases. Qualitative research methods, including observations and interviews, were used to investigate and describe participants' conceptual understanding over time. Participants were interviewed on their understanding of the cause of moon phases before instruction, 3 weeks after instruction, and again in delayed post‐interviews several months after instruction. Patterns and themes in the participants' conceptual understanding were identified through constant‐comparative data analysis. Consistent with results reported earlier, participants who had instruction that included recording and analyzing moon observations over time and psychomotor modeling of changes in moon phases were very likely to hold a scientific conceptual understanding shortly after instruction. The present study indicates a majority of participants continued to hold a scientific understanding six months or more after instruction. However, some participants reverted to alternative conceptions they had shown during the pre‐interview. These results are interpreted utilizing contemporary conceptual change theory. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 303–326, 2007     

Measuring approaches to learning in preschoolers: validating the structure of an instrument for teachers and parents

This study examined a 13-item instrument measuring approaches to learning (AtL) as a component of school readiness in the context of early childhood socio-emotional development. Few instruments, limited to preschool teacher ratings, measure AtL among kindergarteners with short easy-to-use questionnaires. We investigated psychometric properties of the instrument designed to provide practical measures of AtL behaviours identified in the Arizona Early Learning Standards with teacher (n?=?205) and guardian (n?=?1025) samples. We found a one-factor structure via exploratory factor analysis and confirmatory factor analysis (CFA). The multi-group CFA for combined teacher and guardian models indicated a good fit, which demonstrated the structure validity of the AtL instrument. This finding, combined with evidence of reliability of the instrument, supported the educational utility of the AtL as a new tool for measuring school readiness among kindergarteners in Arizona.     

MULTINATIONAL INTEGRATION AND NATIONAL EDUCATION SYSTEMS: THE CASE OF AUSTRIA

This article examines the question of European integration from the vantage point of national education systems. Taking Austria and its education system as examples, it argues that even if Austria should join the European Community, it does not follow that its education system should be merged into a common education system. Just as the European Community is not the same thing as a united Europe, education systems are so closely linked to their individual countries that they should not be turned into supranational organizations, even if other national institutions lend themselves to this kind of integration.