Self‐Compensation in Transparent Conducting F‐Doped SnO2

The factors limiting the conductivity of fluorine‐doped tin dioxide (FTO) produced via atmospheric pressure chemical vapor deposition are investigated. Modeling of the transport properties indicates that the measured Hall effect mobilities are far below the theoretical ionized impurity scattering limit. Significant compensation of donors by acceptors is present with a compensation ratio of 0.5, indicating that for every two donors there is approximately one acceptor. Hybrid density functional theory calculations of defect and impurity formation energies indicate the most probable acceptor‐type defects. The fluorine interstitial defect has the lowest formation energy in the degenerate regime of FTO. Fluorine interstitials act as singly charged acceptors at the high Fermi levels corresponding to degenerately n‐type films. X‐ray photoemission spectroscopy of the fluorine impurities is consistent with the presence of substitutional F_O donors and interstitial F_i in a roughly 2:1 ratio in agreement with the compensation ratio indicated by the transport modeling. Quantitative analysis through Hall effect, X‐ray photoemission spectroscopy, and calibrated secondary ion mass spectrometry further supports the presence of compensating fluorine‐related defects.     

Doping efficiency and energy-level scheme in C60F48-doped zinc–tetraphenylporphyrin films

High resolution synchrotron-based core level spectroscopy was used to examine the energy level alignment at the interface of zinc–tetraphenylporphyrin films doped by the surface acceptor C₆₀F₄₈. Two distinct fluorofullerene charge states were identified, corresponding to ionized and neutral molecules, and their relative concentration as a function of coverage was used to evaluate the probability of occupation of the acceptor lowest unoccupied molecular orbital (LUMO). From an initial acceptor energy of ?0.25 eV, the C₆₀F₄₈ LUMO shifts upwards with coverage due to a doping-induced interfacial dipole potential, and stabilization of the LUMO at an energy 0.45 eV above the Fermi energy was obtained. While the energy difference upon saturation is consistent with the results obtained for other donor–acceptor systems that have been interpreted as Fermi level pinning, the present work shows that the energy offset is a direct consequence of the interplay between Fermi–Dirac statistics in combination with the interfacial dipole potential.     

INCUBATION OF BARLEY KERNEL SECTIONS WITH PURIFIED CELL WALL DEGRADING ENZYMES

The effects of purified Trichoderma reesei endo-xylanase, XYN II and endoglucanases, EG I and EG II on the cell walls of embedded barley cross sections were studied. The cell walls were stained with Calcofluor which is specific for (1–3)(1–4)-β-D-glucans (mixed-linked β-glucans) in histochemical applications. Whereas endosperm cell walls remained highly fluorescent after incubation with buffer, the aleurone cell walls were only weakly fluorescent. Both EG I and EG II were effective in degrading the outer endosperm cell walls, but had little or no effect on the inner endosperm and aleurone cell walls. Corresponding sections incubated with XYN II showed highly intensive fluorescence of aleurone cell walls suggesting that the surface of alaurone cell walls contains a high level of xylan which is removed by xylanase treatment exposing a layer rich in mixed linked β-glucans. This indicates that arabinoxylans and β-glucans in the aleurone cell walls of barley exist as separate, macroscopic layers. Xylanase did not have any Influence on the microstructure of endosperm cell walls which are rich in mixed linked β-glucans. However, incubation with EG II after xylanase treatment caused the aleurone cell walls to become very thin.     

Associations Between Message Features and Subjective Evaluations of the Sensation Value of Antidrug Public Service Announcements

The effective targeting of high sensation-seeking adolescents, who are most at risk for drug abuse, requires the creation of high sensation value messages. Whereas previous research has focused on subjective reactions of receivers as the primary way to define message sensation value (MSV), we conceptualize message sensation value as the formal and content features (audio, visual, and format) of a message that contribute to subjective message sensation evaluations. The three objectives of this study were (a) to identify message design features that would aid in the development of effective prevention messages targeting high sensation seekers, (b) to develop an objective measure of message sensation value based on formal and content features of messages, and (c) to determine whether high message sensation value messages were associated with higher subjective evaluations of message sensation value. In the present study, 418 undergraduates each viewed 10 PSAs selected at random from a pool of 109 PSAs that had been previously coded for message sensation value. Analyses provide support for the central hypothesis of the study, indicating that perceived message sensation value is at least in part a product of the formal and content features of a PSA.     

SOME BARLEY GRAIN AND GREEN MALT PROPERTIES AND THEIR INFLUENCE ON MALT HOT-WATER EXTRACT: II. PROTEIN,PROTEINASE AND MOISTURE

This paper continues the study of variation between varieties in some properties of barley and malt and examines protein-related characters and moisture uptake. Initial rate of moisture uptake was more closely related to enzyme activities than maximum moisture content. Significant varietal variation was found in all characters and this variation was greater than environmental variation with the exception of grain nitrogen concentration. In the endosperm endopeptidase activity was the character most highly correlated with malt hot water extract (HWE). The combined influence of protein- and β-glucan-related characters was investigated and the relative influence of each group of characters on HWE varied in different sections of the grain. In the endosperm the protein- and β-glucan-related characters accounted for 30% and 60% of the variation in HWE respectively.     

Glycosidic linkages of legume,grass and cereal straw cell walls before and after extensive degradation by rumen microorganisms

The technique of methylation analysis for the location of glycosidic linkages in cell wall polysaccharides was applied directly (after dry milling in liquid nitrogen) to whole wheat and barley straws, cell wall preparations from early- and late-cut perennial ryegrass and white clover, and their extensively degraded residues recovered from the rumen. The addition of an internal standard, methyl-β-D-allo-pyranose, to milled samples enabled the recovery of partially-methylated sugars to be quantified, and the recovery of parent sugars from methylated material to be compared with values obtained by direct estimation of monosaccharides by the alditol acetate method. Recovery of sugars from methylated samples was generally higher than that predicted by the alditol acetate method, particularly from digested residues. All four samples of Gramineae showed similar proportions of glycosidic linkages in which (1 →4)-linked xylose and glucose units accounted for more than 80% of total identified partially-methylated sugars. The proportions of glycosidic linkages found in digested residues of straws were essentially the same as those found in the parent material. In residues of the more digestible ryegrass there was a two- to three-fold increase in (1→4)-linked xylose units without branch points at the O-2/O-3 positions, the proportions of these branch points being substantially reduced. A corresponding reduction in the proportion of (1→2)-, (1→3)-and terminally-linked arabinose units was also found. The proportion of both (1→4)- and (1→3)-linked glucose units were also reduced in digested residues. These changes were greater in the early-cut than in the late-cut sample. White clover differed from the Gramineae in a number of respects. Galactose units predominantly in the form of (1→4)-, (1→6)- and terminally-linked units, were the major non-cellulosic sugars present. The proportion of all forms of galactose was reduced in digested residues, but (1→6)-linked units appeared more resistant to degradation than (1→4)-linked units. Like ryegrass, the proportion of xylose units increased in digested residues from clover, while the proportion of glucose decreased. The proportion of (1→4)-linked mannose units, initially present at levels ten times as great as in the Gramineae, was also substantially reduced.     

Revisiting the Worksite in Worksite Health Campaigns: Evidence From a Multisite Organ Donation Campaign

This article advances the beginnings of a general theory of organizational features to aid in understanding why health campaigns that work well in one organization may be ineffectual in another organization. The physical, social, and information structures of organizations are theorized to create an interaction environment that is distinct to each organization and that influences health campaigns. To test this argument, an organ donation campaign was conducted in 46 organizations. Multilevel modeling yielded mixed findings. Physical structure was negatively associated with signing an organ donor card. Social structure and information structure were positively associated with communication with coworkers about donation and communicative peer influence. Industry type was positively associated with knowledge change.     

Multi‐Material Tissue Engineering Scaffold with Hierarchical Pore Architecture

Multi‐material polymer scaffolds with multiscale pore architectures are characterized and tested with vascular and heart cells as part of a platform for replacing damaged heart muscle. Vascular and muscle scaffolds are constructed from a new material, poly(limonene thioether) (PLT32i), which meets the design criteria of slow biodegradability, elastomeric mechanical properties, and facile processing. The vascular–parenchymal interface is a poly(glycerol sebacate) (PGS) porous membrane that meets different criteria of rapid biodegradability, high oxygen permeance, and high porosity. A hierarchical architecture of primary (macroscale) and secondary (microscale) pores is created by casting the PLT32i prepolymer onto sintered spheres of poly(methyl methacrylate) (PMMA) within precisely patterned molds followed by photocuring, de‐molding, and leaching out the PMMA. Prefabricated polymer templates are cellularized, assembled, and perfused in order to engineer spatially organized, contractile heart tissue. Structural and functional analyses show that the primary pores guide heart cell alignment and enable robust perfusion while the secondary pores increase heart cell retention and reduce polymer volume fraction.     

A thyristor- and thermistor-based inrush current limiter for DC-link start-up

Large inrush currents can be harmful to equipment subjected to it and can also disturb other devices through voltage dips. Traditional ways of dealing with large inrush currents include the usage of parasitic elements in the supply, negative temperature coefficient (NTC) resistances and start-up relays. These solutions have several disadvantages among which are a non-negligible standby consumption, using a relay or a compromise between inrush current and load losses using an NTC. This paper proposes a solution which solves these disadvantages. The proposed circuit uses a semi-controlled bridge rectifier requiring a very low standby power consumption and is capable of withstanding grid interruptions. Moreover, it is designed to power on only when the load is not too heavy. This is accomplished by the use of positive temperature coefficient thermistors. The presented solution can be used for DC-link start-up circuits in applications with a power range from several watts up to a few kilowatts and it is particularly suitable for on-board battery chargers designed for electrical vehicles.     

Design of Engineered Elastomeric Substrate for Stretchable Active Devices and Sensors

In the field of flexible electronics, emerging applications require biocompatible and unobtrusive devices, which can withstand different modes of mechanical deformation and achieve low complexity in the fabrication process. Here, the fabrication of a mesa‐shaped elastomeric substrate, supporting thin‐film transistors (TFTs) and logic circuits (inverters), is reported. High‐relief structures are designed to minimize the strain experienced by the electronics, which are fabricated directly on the pillars' surface. In this design configuration, devices based on amorphous indium‐gallium‐zinc‐oxide can withstand different modes of deformation. Bending, stretching, and twisting experiments up to 6 mm radius, 20% uniaxial strain, and 180° global twisting, respectively, are performed to show stable electrical performance of the TFTs. Similarly, a fully integrated digital inverter is tested while stretched up to 20% elongation. As a proof of the versatility of mesa‐shaped geometry, a biocompatible and stretchable sensor for temperature mapping is also realized. Using pectin, which is a temperature‐sensitive material present in plant cells, the response of the sensor shows current modulation from 13 to 28 °C and functionality up to 15% strain. These results demonstrate the performance of highly flexible electronics for a broad variety of applications, including smart skin and health monitoring.