Climbing Plant‐Inspired Micropatterned Devices for Reversible Attachment

Climbing plants have evolved over millions of years and have adapted to unpredictable scenarios in unique ways. These crucial features make plants an outstanding biological model for scientists and engineers. Inspired by the ratchet‐like attachment mechanism of the hook‐climber Galium aparine, a novel micropatterned flexible mechanical interlocker is fabricated using a 3D direct laser lithography technique. The artificial hooks are designed based on a morphometric analysis of natural hooks. They are characterized in terms of pull‐off and shear forces, both in an array and as individual hooks. The microprinted hooks array shows high values of pull‐off forces (up to F_⊥ ≈ 0.4 N cm^?2) and shear forces (up to F_// ≈ 13.8 N cm^?2) on several rough surfaces (i.e., abrasive materials, fabrics, and artificial skin tissues). The contact separation forces of individual artificial hooks are estimated when loads with different orientations are applied (up to F ≈ 0.26 N). In addition, a patterned tape with directional microhooks is integrated into a mobile platform to demonstrate its climbing ability on inclined surfaces of up to 45°. This research opens up new opportunities for prototyping the next generation of mechanical interlockers, particularly for soft‐ and microrobotics, the textile industry, and biomedical fields.     

Metal–polymer–metal sandwiches with local metal reinforcements: A study on formability by deep drawing and bending

The formability of metal–polymer–metal sandwich composites with embedded different solid and mesh steel inlays was investigated with the aim to gain information about their forming behaviour by shaping, especially deep drawing and bending. Therefore the geometry and the size of the local inlays have been varied. The reduction in thickness of these composites was quantified by photogrammetry. As a result the formability of sandwich composites with solid steel inlays is lower compared to non-reinforced ones. Sandwiches with mesh inlays showed a slightly increased thinning compared to sandwiches with circular solid inlays. Both variations revealed good formability. The results will be used for future tailoring of sandwich structures with particularly demanded properties.     

Short-Crack Fracture Toughness of Silicon Carbide

The fracture toughness of four different silicon carbides was measured using single-edge precracked beam (SEPB) and indentation/strength techniques. Two were development grades with similar microstructures and chemistries, and yet exhibited different fracture modes. The grade that exhibited a predominantly intergranular fracture had an SEPB fracture toughness (6.4 MPa√m) 88% higher than the one that showed primarily a transgranular fracture (3.4 MPa√m). The higher fracture toughness was associated with a modest increase in average strength (25%), although there was a significant increase in the Weibull modulus (11–32). Fracture toughness at short crack lengths was assessed by an indentation method that used fracture strengths, crack lengths at fracture, and a new method of estimating the constant δ that characterizes the residual driving force of the plastic zones based on the stable growth of the indentation cracks from the initial ( c ₀) to the instability ( c ^*) lengths. The results showed a rising crack-growth-resistance behavior for the grade exhibiting intergranular fracture, while the grade showing transgranular fracture had a flat crack-growth resistance. Tests on two commercial grades of silicon carbide showed similar behaviors associated with the respective fracture modes.     

All or none hypothesis: A global-default mode that characterizes the brain and mind.

It is proposed that the mind and brain often work at a gross level and only with fine tuning or inhibition act in a more differentiated manner, even when one might think the domains being issued the global command should be distinct. This applies to disparate findings in cognitive science and neuroscience in both children and adults. Thus, it is easier to switch everything, or nothing, than to switch one thing (the rule one is following or which button to press) but not the other. It is easier to issue the same command to both hands than to move only one hand. If one needs to respond to the opposite (or antonym) of a stimulus, one is faster if the correct response is to the side opposite the stimulus. People tend to think of the nervous system as sending out very precise commands only to the relevant recipient, but it appears that often the command goes out more globally and then parts of the system need to be inhibited from acting on the command. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Double-blind photoarray administration as a safeguard against investigator bias": Correction to Phillips et al. (1999).

Reports an error in "Double-blind photoarray administration as a safeguard against investigator bias" by Mark R. Phillips, Bradley D. McAuliff, Margaret Bull Kovera and Brian L. Cutler (Journal of Applied Psychology, 1999[Dec], Vol 84[6], 940-951). On page 947, the graphs within Figure 1 were incorrectly labeled. The corrected figure appears in this erratum. (The following abstract of the original article appeared in record 1999-15531-009.) This experiment examined whether a photoarray administrator's knowledge of a suspect's identity increased false identification rates. Fifty participant–administrators (PAs) presented 50 participant–witnesses (PWs) two perpetrator-absent photoarrays following a live staged crime involving two perpetrators. For one photoarray per trial, the experimenter revealed the suspect's identity to the PA. Each PA presented the photoarrays sequentially or simultaneously in the presence or absence of an observer. When the observer was present, PA knowledge of the suspect's identity had a biasing effect in sequential photoarrays only. This pattern did not emerge when the observer was absent. The experimental manipulations did not affect PAs' and PWs' ratings of photoarray fairness or PWs' ratings of pressure to make an identification. These data suggest that only administrators who are blind to the suspect's identity should present sequential photoarrays. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A latent curve model of parental motivational practices and developmental decline in math and science academic intrinsic motivation.

A longitudinal approach was used to examine the effects of parental task-intrinsic and task-extrinsic motivational practices on academic intrinsic motivation in the subject areas of math and science. Parental task-intrinsic practices comprise encouragement of children’s pleasure and engagement in the learning process, whereas task-extrinsic practices comprise parents’ provision of external rewards and consequences contingent on children’s task performance. A conditional latent curve model was fit to data from the Fullerton Longitudinal Study (A. W. Gottfried, A. E. Gottfried, & D. W. Guerin, 2006), with academic intrinsic motivation in math and science assessed from ages 9 to 17 and parental motivational practices measured when children were age 9. The results indicated that task-intrinsic practices were beneficial with regard to children’s initial levels of motivation at age 9 as well as with regard to motivational decline through age 17. Conversely, parents’ use of task-extrinsic practices was adverse with regard to children’s motivation both at age 9 and across the 8-year interval. Theoretical implications of the findings with regard to academic intrinsic motivation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical influence in phonetic decision making: Evidence from subcategorical mismatches.

In 5 experiments, listeners heard words and nonwords, some cross-spliced so that they contained acoustic-phonetic mismatches. Performance was worse on mismatching than on matching items. Words cross-spliced with words and words cross-spliced with nonwords produced parallel results. However, in lexical decision and 1 of 3 phonetic decision experiments, performance on nonwords cross-spliced with words was poorer than on nonwords cross-spliced with nonwords. A gating study confirmed that there were misleading coarticulatory cues in the cross-spliced items; a sixth experiment showed that the earlier results were not due to interitem differences in the strength of these cues. Three models of phonetic decision making (the Race model, the TRACE model, and a postlexical model) did not explain the data. A new bottom-up model is outlined that accounts for the findings in terms of lexical involvement at a dedicated decision-making stage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time-resolved three-dimensional molecular tracking in live cells

We report a method for tracking individual quantum dot (QD) labeled proteins inside of live cells that uses four overlapping confocal volume elements and active feedback once every 5 ms to follow three-dimensional molecular motion. This method has substantial advantages over three-dimensional molecular tracking methods based upon charge-coupled device cameras, including increased Z-tracking range (10 μm demonstrated here), substantially lower excitation powers (15 μW used here), and the ability to perform time-resolved spectroscopy (such as fluorescence lifetime measurements or fluorescence correlation spectroscopy) on the molecules being tracked. In particular, we show for the first time fluorescence photon antibunching of individual QD labeled proteins in live cells and demonstrate the ability to track individual dye-labeled nucleotides (Cy5-dUTP) at biologically relevant transport rates. To demonstrate the power of these methods for exploring the spatiotemporal dynamics of live cells, we follow individual QD-labeled IgE-FcεRI receptors both on and inside rat mast cells. Trajectories of receptors on the plasma membrane reveal three-dimensional, nanoscale features of the cell surface topology. During later stages of the signal transduction cascade, clusters of QD labeled IgE-FcεRI were captured in the act of ligand-mediated endocytosis and tracked during rapid (~950 nm/s) vesicular transit through the cell.