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Large, distributed collections of miniaturized, wireless electronic devices.sup.1,2 may form the basis of future systems for environmental monitoring.sup.3, population surveillance.sup.4, disease management.sup.5 and other applications that demand coverage over expansive spatial scales. Aerial schemes to distribute the components for such networks are required, and--inspired by wind-dispersed seeds.sup.6--we examined passive structures designed for controlled, unpowered flight across natural environments or city settings. Techniques in mechanically guided assembly of three-dimensional (3D) mesostructures.sup.7-9 provide access to miniature, 3D fliers optimized for such purposes, in processes that align with the most sophisticated production techniques for electronic, optoelectronic, microfluidic and microelectromechanical technologies. Here we demonstrate a range of 3D macro-, meso- and microscale fliers produced in this manner, including those that incorporate active electronic and colorimetric payloads. Analytical, computational and experimental studies of the aerodynamics of high-performance structures of this type establish a set of fundamental considerations in bio-inspired design, with a focus on 3D fliers that exhibit controlled rotational kinematics and low terminal velocities. An approach that represents these complex 3D structures as discrete numbers of blades captures the essential physics in simple, analytical scaling forms, validated by computational and experimental results. Battery-free, wireless devices and colorimetric sensors for environmental measurements provide simple examples of a wide spectrum of applications of these unusual concepts. With a design inspired by wind-dispersed seeds, a series of three-dimensional passive fliers at the macro-, meso- and microscale are realized that can bear active electronic payloads., Author(s): Bong Hoon Kim [sup.1] [sup.2] , Kan Li [sup.3] [sup.4] , Jin-Tae Kim [sup.5] , Yoonseok Park [sup.5] , Hokyung Jang [sup.6] , Xueju Wang [sup.7] , Zhaoqian Xie [...]

This article addresses how we learn technology across the lifespan. After outlining findings of research into how children, adolescents, teens and adults learn technology, we address theoretical shifts from sociocultural to technocultural theories of cognition and reorientations from mediated to cyborgenic learning. The balance of the article describes effective methods for researching cognition and technology. In the process of outlining key findings from research, we emphasize the links among methods and theories employed, data produced and conclusions drawn. Our goal is to sketch a lifelong learning context for undertaking studies of cognition and technology, and to provide a methodological and theoretical analysis for researchers venturing into this dynamic and volatile field. In summary, we provide a far-ranging agenda for researching cognition and technology.

Light-scattering technology in the undergraduate curriculum is discussed. At the University of Northern Iowa, a Wyatt miniDAWN light-scattering detector was acquired and experiments using the technology to measure the molecular weight of macromolecules replaced an outdated experiment using determination of molecular weight using freezing-point depression. The technique also has great potential in biochemistry teaching and in other areas of undergraduate instruction and is valuable for undergraduate research. Practical and pedagogical problems are discussed.

In the environment, bacteria show close association, such as interspecies interaction, with other bacteria as well as host organisms. The type VI secretion system (T6SS) in gram‐negative bacteria is involved in bacterial competition or virulence. The plant pathogen Burkholderia glumae BGR1, causing bacterial panicle blight in rice, has four T6SS gene clusters. The presence of at least one T6SS gene cluster in an organism indicates its distinct role, like in the bacterial and eukaryotic cell targeting system. In this study, deletion mutants targeting four tssD genes, which encode the main component of T6SS needle formation, were constructed to functionally dissect the four T6SSs in B. glumae BGR1. We found that both T6SS group_4 and group_5, belonging to the eukaryotic targeting system, act independently as bacterial virulence factors toward host plants. In contrast, T6SS group_1 is involved in bacterial competition by exerting antibacterial effects. The ΔtssD1 mutant lost the antibacterial effect of T6SS group_1. The ΔtssD1 mutant showed similar virulence as the wild‐type BGR1 in rice because the ΔtssD1 mutant, like the wild‐type BGR1, still has key virulence factors such as toxin production towards rice. However, metagenomic analysis showed different bacterial communities in rice infected with the ΔtssD1 mutant compared to wild‐type BGR1. In particular, the T6SS group_1 controls endophytic plant‐associated bacteria such as Luteibacter and Dyella in rice plants and may have an advantage in competing with endophytic plant‐associated bacteria for settlement inside rice plants in the environment. Thus, B. glumae BGR1 causes disease using T6SSs with functionally distinct roles. [ABSTRACT FROM AUTHOR]

We fabricated a functional pentacene/CH 3 NH 3 PbI 3-x Cl x perovskite interface where optical gating and field assisted charge retention occur. Using a pentacene/perovskite field effect transistor (FET) test platform, we investigated the interfacial charge transfer associated with optical gating through threshold voltage measurements under illumination. Importantly, bistable electrical conduction in pentacene/perovskite FET devices was achieved as a result of field-induced charge retention at the interface and the origin is discussed to be associated with interfacial charging at the pentacene/perovskite interface. Interfacial contact modification associated with ion migration and other possible effects in the perovskite layer plays a crucial role in forming a functional interface involving organic semiconducting materials.