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This work reports the first demonstration that a chemoresistive sensor can be used to detect the aggregation pheromone of flour beetles. To prepare the sensing element of such a sensor, a novel functionalization method was developed to amplify amine groups on the surface of carbon nanotubes (CNTs). Unlike traditional amine-amplification approaches in which amplification efficiency is significantly reduced by self-crosslinking, the current amine amplification process was self-crosslinking-free due to the use of a home-made compound in which amine groups were protected by Boc (tert-butyloxycarbonyl) protecting groups and could be deprotected as needed. The inkjet ink formulated from the functionalized CNTs, together with an amine-rich compound and a commercial silver nanoparticle-based inkjet ink, was used to fabricate (via inkjet-printing and drop-casting) lightweight, flexible, and miniature-sized chemiresistive sensors for 4,8-dimethyldecanal (DMD), a compound known to be the aggregation pheromone of several species of flour beetles. A home-built gas sensing system, including a commercial gas generator, a DMD permeation tube with its emission rate certified, a data-acquisition system, and some home-developed LabVIEW-based programs, was utilized to perform the DMD sensing trials. The sensors showed ultra-high sensitivity to synthetic aggregation pheromone DMD, as indicated by their prompt and significant responses to 100 ppb DMD vapor. A mechanism for the sensitive sensing of DMD is proposed. [ABSTRACT FROM AUTHOR]

A scalable, low-cost process for fabricating copper-based microwave components on flexible, paper-based substrates is demonstrated. An inkjet printer is used to deposit a catalyst-bearing solution (tailored for such printing) in a desired pattern on commercially-available, recyclable, non-toxic (Teslin®) paper. The catalystbearing paper is then immersed in an aqueous copper-bearing solution to allow for electroless deposition of a compact and conformal layer of copper in the inkjet-derived pattern. Meander monopole antennas comprised of such electroless-deposited copper patterns on paper exhibited comparable performance as for antennas synthesized via inkjet printing of a commercially-available silver nanoparticle ink. However, the solution-based patterning and electroless copper deposition process avoids nozzle-clogging problems and costs associated with noble metal particle-based inks. This process yields compact conductive copper layers without appreciable oxidation and without the need for an elevated temperature, post-deposition thermal treatment commonly required for noble metal particle-based ink processes. This low-cost copper patterning process is readily scalable on virtually any substrate and may be used to generate a variety of copper-based microwave devices on flexible, paper-based substrates. [ABSTRACT FROM AUTHOR]

A heat-stable growth factor has been purified to homogeneity from human placenta. Purification procedure involved extraction with acidic medium, precipitation using ethanol, DE-52 ion-exchange chromatography, and reversed-phase HPLC. The purified preparation has been named human placental growth factor-1 (HPGF-1), which simulates the proliferation of some cell lines, such as human amniotic cell, mouse marrow tumor cell, and mouse fibroblast cell. The growth factor has an approximate molecular weight of 1 900. It is a glycopeptide which contains a polypeptide chain consisting of 10 amino acid residues with molecular weight of 1 195. The N-terminal residue of the polypeptide chain part is phenylalanine. The molecular weight of non-peptide part is 682. The isolectric point of the growth factor is pI 6.8. [ABSTRACT FROM AUTHOR]

A bio-enabled, environmentally-friendly, and maximally mild layer-by-layer approach has been developed to surface modify inherently hydrophobic Kapton HN substrates to allow for great printability of both water- and organic solvent-based inks thus facilitating the full-inkjet-printing of flexible electronic devices. Different from the traditional Kapton surface modification approaches which are structure-compromising and use harsh conditions to target, and oxidize and/or remove part of, the surface polyimide of Kapton, the present Kapton surface modification approach targeted the surface electric charges borne by its additive particles, and was not only the first to utilize environmentally-friendly clinical biomolecules to build up a thin film of protamine-heparin complex on Kapton, but also the first to be conducted under minimally destructive and maximally mild conditions. Besides, for electrically charged ink particles, the present surface modification method can enhance the uniformity of the inkjet-printed films by reducing the 'coffee ring effect'. As a proof-of-concept demonstration, reduced graphene oxide-based gas sensors, which were flexible, ultra-lightweight, and miniature-sized, were fully-inkjet-printed on surface modified Kapton HN films and tested for their sensitivity to dimethyl methylphosphonate (a nerve agent simulant). Such fabricated sensors survived a Scotch-tape peel test and were found insensitive to repeated bending to a small 0.5 cm radius. [ABSTRACT FROM AUTHOR]