Bifunctional Thiourea-Catalyzed Enantioselective Aza-Friedel-Crafts Reaction of 3-Aminobenzofurans with Isatin-Derived Ketimines.

A quinine-derived thiourea-promoted enantioselective aza-Friedel-Crafts reaction of 3-aminobenzofurans with isatin-derived ketimines is developed, providing a variety of 3-benzofuran-3-amino-2-oxindoles bearing a quaternary stereocenter with good to excellent yields (72-95%) and moderate to excellent enantioselectivities (48-97%). The synthetic potential of this concise and efficient protocol is revealed by gram-scale preparation and further transformation of the adduct to an optically pure spirocyclic oxindole.

Imaging of mtHyPer7, a Ratiometric Biosensor for Mitochondrial Peroxide, in Living Yeast Cells.

Mitochondrial dysfunction, or functional alteration, is found in many diseases and conditions, including neurodegenerative and musculoskeletal disorders, cancer, and normal aging. Here, an approach is described to assess mitochondrial function in living yeast cells at cellular and subcellular resolutions using a genetically encoded, minimally invasive, ratiometric biosensor. The biosensor, mitochondria-targeted HyPer7 (mtHyPer7), detects hydrogen peroxide (H2O2) in mitochondria. It consists of a mitochondrial signal sequence fused to a circularly permuted fluorescent protein and the H2O2-responsive domain of a bacterial OxyR protein. The biosensor is generated and integrated into the yeast genome using a CRISPR-Cas9 marker-free system, for more consistent expression compared to plasmid-borne constructs. mtHyPer7 is quantitatively targeted to mitochondria, has no detectable effect on yeast growth rate or mitochondrial morphology, and provides a quantitative readout for mitochondrial H2O2 under normal growth conditions and upon exposure to oxidative stress. This protocol explains how to optimize imaging conditions using a spinning-disk confocal microscope system and perform quantitative analysis using freely available software. These tools make it possible to collect rich spatiotemporal information on mitochondria both within cells and among cells in a population. Moreover, the workflow described here can be used to validate other biosensors.

Effect of Five Driver's Behavior Characteristics on Car-Following Safety.

Driver's behavior characteristics (DBCs) influence car-following safety. Therefore, this paper aimed to analyze the effect of different DBCs on the car-following safety based on the desired safety margin (DSM) car-following model, which includes five DBC parameters. Based on the Monte Carlo simulation method, the effect of DBCs on car-following safety is investigated under a given rear-end collision (RECs) condition. We find that larger subjective risk perception levels can reduce RECs, a smaller acceleration sensitivity (or a larger deceleration sensitivity) can improve car-following safety, and a faster reaction ability of the driver can avoid RECs in the car-following process. It implies that DBCs would cause a traffic wave in the car-following process. Therefore, a reasonable value of DBCs can enhance traffic flow stability, and a traffic control strategy can improve car-following safety by using the adjustment of DBCs.

Multifocal 1064 nm Raman imaging of carbon nanotubes.

We show that multifocal 1064 nm Raman microscopy based on Hadamard-coded multifocal arrays is useful for imaging carbon nanotubes (CNTs) that would otherwise be damaged if a conventional single focus microscope design is used. The damage threshold for CNTs, dependent on laser power density and exposure time, limits the spectral detection sensitivity of single focus Raman imaging. With multifocal detection, the signal-to-noise ratio of the Raman spectra were improved by more than a factor of three, allowing for the G and D Raman bands of CNTs to be detected while avoiding specimen damage. These results lay the foundation for developing multifocal 1064 nm Raman microscopy as a tool for in situ imaging of CNTs in plant material.

Long-Range Self-Assembly via the Mutual Lorentz Force of Plasmon Radiation.

Long-range interactions often proceed as a sequence of hopping through intermediate, statistically favored events. Here, we demonstrate predictable mechanical dynamics of particles that arise from the Lorentz force between plasmons. Even if the radiation is weak, the nonconservative Lorentz force produces stable locations perpendicular to the plasmon oscillation; over time, distinct patterns emerge. Experimentally, linearly polarized light illumination leads to the formation of 80 nm diameter Au nanoparticle chains, perpendicularly aligned, with lengths that are orders of magnitude greater than their plasmon near-field interaction. There is a critical intensity threshold and optimal concentration for observing self-assembly.

Improved Anisotropic Thermoelectric Behavior of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) via Magnetophoresis.

There is strong demand for achieving morphological control of conducting polymers in its many potential applications, from energy harvesting to spintronics. Here, the static magnetic-field-induced alignment of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) particles is demonstrated. PEDOT:PSS thin films cast under modest mT-level magnetic fields exhibit a fourfold increase in the Seebeck coefficient and doubled electrical conductivity. Atomic force microscopy measurements confirm the presence of conducting islands that exhibit a 10-fold increase in the local charge carrier mobility and threshold behavior that is associated with phase separation. High-resolution scanning electron microscopy identifies a consistent structural coil-to-rod transition, and three-dimensional time-of-flight secondary-ion mass spectrometry imaging shows that the rodlike structures coincide with PEDOT domains that generally align with the magnetic field and cluster on the outer surface. Grazing-incidence small-angle X-ray scattering, Raman spectra, electron paramagnetic resonance, and circular dichroism spectroscopy point to the physical nature of the magnetophoretic alignment, which is expected to occur via magnetic coupling of PEDOT domains with polaron modes. Because casting under mT-level magnetic fields increases the electrical conductivity and Seebeck coefficient of PEDOT:PSS thin films without additional dopants that commonly limit the thermoelectric performance, our research reveals that low-field magnetophoresis significantly influences the structure and corresponding physical properties of PEDOT:PSS. Our results also point to concerns that the presence of small external magnetic fields in laboratory settings may appreciably and inadvertently influence the PEDOT:PSS morphology during settling, drying, or annealing processes.

Metacognitive control: Shifting from habitual to agenda processes on item selection during study in elementary school children.

BACKGROUND: Like adults, children need to allocate study time and endeavour optimally in order to enhance learning effectiveness. AIMS: The aim of this study was to investigate the development of shifting from habitual to agenda-based processes on study decisions. SAMPLE: The participants were 309 children in the second, fourth, and sixth grades. METHODS: We adopted the research paradigm proposed by Ariel and Dunlosky (2013, Mem. Cognit., 41, 416). In Experiment 1, the students selected items to study either with or without time constraint. In Experiment 2, the students were instructed to select all three items or one item to study per trial. RESULTS: The results of Experiment 1 showed that for sixth graders, the likelihood of selecting high-value items under the restricted-study-time condition was higher than that under the restricted-total-time condition; second and fourth graders failed to construct an agenda of prioritizing high-reward items for study in the restricted-study-time condition. In Experiment 2, when students were instructed to select one item to study per trial, high-value items were prioritized over items on the left of the array for sixth graders; on the contrary, second and fourth graders seemed to choose item for study arbitrary, although they tend to choose high-value items compared with their choice pattern in no-choice-limit condition. CONCLUSIONS: The results indicate that children can shift towards agenda-based process when habitual responding cannot maximize reward, and there is an age-related improvement in shifting between grade 4 and grade 6.

Out of Lust or Jealousy: The Effects of Mate-Related Motives on Study-Time Allocation to Faces Varying in Attractiveness.

Although a growing number of empirical studies have revealed that activating mate-related motives might exert a specific set of consequences for human cognition and behaviors, such as attention and memory, little is known about whether mate-related motives affect self-regulated learning. The present study examined the effects of mate-related motives (mate-search and mate-guarding) on study-time allocation to faces varying in attractiveness. In two experiments, participants in mate-related priming conditions (Experiment 1: mate-search; Experiment 2: mate-guarding) or control conditions studied 20 female faces (10 highly attractive, 10 less attractive) during a self-paced study task, and then were given a yes/no face recognition task. The finding of Experiment 1 showed that activating a mate-search motive led the male participants to allocate more time to highly attractive female faces (i.e., perceived potential mates) than to less attractive ones. In Experiment 2, female participants in the mate-guarding priming condition spent more time studying highly attractive female faces (i.e., perceived potential rivals) than less attractive ones, compared to participants in the control condition. These findings illustrate the highly specific consequences of mate-related motives on study-time allocation, and highlight the value of exploring human cognition and motivation within evolutionary and self-regulated learning frameworks.