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Low-bandgap semiconductor nanowires (NWs) attract considerable interest for mid-infrared (MIR) photonics and optoelectronics, where ideal candidate materials require surface-passivated core–shell systems with large tunability in band offset, lineup, and emission wavelength while maintaining close lattice-matching conditions. Here, we propose and demonstrate epitaxial InAs–AlAsSb core–shell NW arrays on silicon (Si) that offer exceptional control over both the internal strain close to lattice-matching as well as band lineups tunable between type-I and type-II, with almost no analogue in the III–V materials family. We develop direct monolithic growth of high-uniformity InAs–AlAsSb NWs with wide tunability in shell composition and employ correlated Raman scattering and micro-photoluminescence spectroscopy to elaborate the interplay among hydrostatic strain, band lineup, and emission energy of the NW core luminescence tuned from ∼0.4 to 0.55 eV. Electronic structure calculations further support the experimentally observed tunability between type-I and type-II band lineups. The Si-integrated InAs-AlAsSb NW materials system holds large prospects not only for on-chip MIR photonics but also for other applications including high-speed transistors and NW-based hot carrier solar cells.

Isolated sorghum (Sorghum bicolor) storage proteins (kafirins) have been successfully used in the production of several bio-materials including adhesives, films, micro-particles, fibers, and biological scaffold material. Comparatively little research has been conducted on the use of isolated kafirins in food products or to produce bioactive peptides via hydrolysis for nutritional uses. To support such research, the aim of this study was to compare existing methods for bulk isolation of sorghum kafirins with the goal of identifying a solvent with the least toxicity that maintained a high extraction rate from food grade sorghum flour. A secondary goal was to characterize the kafirin isolates produced from various extraction methods to provide some information on their potential use in food products to guide future research in this area. Five different extraction methods were compared including 1) aqueous ethanol containing NaOH and sodium metabisulfite, 2) glacial acetic acid, 3) aqueous ethanol with sodium metabisulfite, 4) aqueous ethanol at acidic pH, and 5) alkaline pH alone. The protein contents of the kafirin isolates obtained by the five methods ranged from 49.76% to 56.83%. Kafirin isolates were characterized using reversed phase (RP)-high performance liquid chromatography (HPLC), which revealed substantial variability in the various kafirin patterns among the extraction methods tested. However, characterization of the kafirin isolates by size exclusion chromatography (SEC) did not show a high degree of variability among the methods tested. Likewise, analysis of the samples using sodium dodecyl sulphate - polyacrylamide gel electrophoresis (SDS-PAGE) showed essentially the same band profiles but with different band intensities among kafirin extraction methods. Surface hydrophobicity of the kafirin isolates varied considerably with isolates extracted with glacial acetic acid and aqueous ethanol plus sodium metabisulfite the most hydrophobic as indicated by hydrophobic dye binding.

Until now, organic semiconductors have failed to achieve high performance in highly integrated, sub-100 nm transistors. Consequently, single-crystalline materials such as single-walled carbon nanotubes, MoS2 or inorganic semiconductors are the materials of choice at the nanoscale. Here we show, using a vertical field-effect transistor design with a channel length of only 40 nm and a footprint of 2 × 80 × 80 nm2, that high electrical performance with organic polymers can be realized when using electrolyte gating. Our organic transistors combine high on-state current densities of above 3 MA cm−2, on/off current modulation ratios of up to 108 and large transconductances of up to 5,000 S m−1. Given the high on-state currents at such large on/off ratios, our novel structures also show promise for use in artificial neural networks, where they could operate as memristive devices with sub-100 fJ energy usage. A vertical, electrolyte-gated organic transistor shows high on-state current densities, large on/off ratio and the potential for use in artificial neural networks.

Sorghum (Sorghum bicolor L.) is a gluten-free cereal with many varieties containing greater amounts of bioactive compounds than other grains. In this work, the phenolic composition and antioxidant capacity were compared in three sorghum varieties grown in the Mediterranean, consisting of different pericarp colors: white, red, and black. The qualitative and quantitative profiles of acidified aqueous methanol extracts of whole grain sorghum flours were elucidated through ultrahigh performance liquid chromatography (UHPLC) coupled to photodiode array (PDA) and ion trap time-of-flight (IT-TOF) mass spectrometry. The investigated sorghum varieties contained polyamines, such as spermidines, and polyphenolic compounds belonging to different classes: hydroxycinnamic acids, flavanols, flavones, and flavanones. Pyrano-flavanone-flavanols were detected only in the black sorghum. Precolumn and postcolumn 2,2′-diphenyl-1-picrylhydrazyl (DPPH)· radical scavenging assays to determine the main antioxidant compounds isolated from sorghum were developed. These results will further help develop sorghum varieties containing polyphenols relevant to the potential prevention of human diseases.

A white food-grade waxy sorghum Tw variety, grown in two Mediterranean sites (named Tw1M and Tw1S) was evaluated for nutrient composition and fatty acid- and mineral concentrations in order to determine the suitability of producing waxy sorghum for human uses in southern Italy. The nutritional values of the grains of the Tw inbred line grown in the two trial fields were substantially the same, except for slight differences in ash level and accordingly slight variation in mineral composition. In samples from both locations, a higher percentage of K was observed among the nutritionally essential macro-elements, and higher percentages of Zn, Fe, Mn, Cu, Al among the nutritionally essential micro-element along with a strong difference in Cd content was among trace elements. Across both sites linoleic, oleic and palmitic were the most abundant fatty acids, while very slight variations in the content of minerals were found among the two samples examined. These results demonstrate the importance of developing agronomically productive waxy sorghum varieties suitable for growth in non-traditional sorghum producing regions both as a food and feed crop (i.e. with good nutritional quality) and for utilization in new products at the industrial level.

Ionic liquids enable efficient gating of materials with nanoscale morphology due to the formation of a nanoscale double layer that can also follow strongly vaulted surfaces. On carbon nanotubes, this can lead to the formation of a cylindrical gate layer, allowing an ideal control of the drain current even at small gate voltages. In this work, we apply ionic liquid gating to chirality-sorted (9, 8) carbon nanotubes bridging metallic electrodes with gap sizes of 20 nm and 10 nm. The single-tube devices exhibit diameter-normalized current densities of up to 2.57 mA/μm, on-off ratios up to 104, and a subthreshold swing down to 100 mV/dec. Measurements after long vacuum storage indicate that the hysteresis of ionic liquid gated devices depends not only on the gate voltage sweep rate and the polarization dynamics but also on charge traps in the vicinity of the carbon nanotube, which, in turn, might act as trap states for the ionic liquid ions. The ambipolar transfer characteristics are compared with calculations based on the Landauer–Buttiker formalism. Qualitative agreement is demonstrated, and the possible reasons for quantitative deviations and possible improvements to the model are discussed. Besides being of fundamental interest, the results have potential relevance for biosensing applications employing high-density device arrays.

Until now, organic semiconductors have failed to achieve high performance in highly integrated, sub-100 nm transistors. Consequently, single-crystalline materials such as single-walled carbon nanotubes, MoS

Advanced materials 29(26), 1606283 - (2017). doi:10.1002/adma.201606283, A method has been developed to stabilize and transfer nanofilms of functional organic semiconductors. The method is based on crosslinking of their topmost layers by low energy electron irradiation. The films can then be detached from their original substrates and subsequently deposited onto new solid or holey substrates retaining their structural integrity. Grazing incidence X-ray diffraction, X-ray specular reflectivity, and UV–Vis spectroscopy measurements reveal that the electron irradiation of ≈50 nm thick pentacene films results in crosslinking of their only topmost ≈5 nm (3–4 monolayers), whereas the deeper pentacene layers preserve their pristine crystallinity. The electronic performance of the transferred pentacene nanosheets in bottom contact field-effect devices is studied and it is found that they are fully functional and demonstrate superior charge injection properties in comparison to the pentacene films directly grown on the contact structures by vapor deposition. The new approach paves the way to integration of the organic semiconductor nanofilms on substrates unfavorable for their direct growth as well as to their implementation in hybrid devices with unusual geometries, e.g., in devices incorporating free-standing sheets., Published by Wiley-VCH, Weinheim

Sorghum has been grown as a food crop for many centuries in Africa and Asia and it is a cereal option for celiac patients. Due to its properties as a wheat-free food, interest is increasing in cultivating sorghum in Mediterranean countries. To evaluate the agronomic characteristics of growth in the Mediterranean area, six hybrids of sorghum (Sorghum bicolor L. Moench), representing different maturity classes, were selected and tested in experimental trials for 2 years in San Bartolomeo in Galdo (BN) hill, South Italy. The results showed moderate variation in adaptation of these hybrids as measured by differences in grain yields (4.60 to 7.30 t ha-1) and other pheno-morphological traits. In particular, the hybrid SW6129W from Bolivia and the hybrid SASG05W from Argentina had grain yields higher than others tested in these trials. Our results demonstrated that selected food-grade hybrids from South America, have agronomic characteristics well-suited for cultivation in Mediterranean countries.

Although sorghum has been used for centuries as a food-crop in Africa and India, researchers in the United States and Europe have only relatively recently become interested in the potential of this unique cereal. Much of this interest focuses on the potential use of sorghum in food product development for individuals with allergies to foods containing wheat-based flours. Because it lacks gluten, sorghum is considered safe for people diagnosed with celiac disease, a condition marked by intolerance to gluten. Recent studies have shown that certain sorghum varieties, tan-plant sorghums, can be used to produce high-quality food and beverage products including cookies, waffles, flour, bread, noodles and beer. The intention is to promote the use and marketing of these sorghums in the Italian Campania Region for sorghum flours suitable as food for celiac patients.