Biosynthetic Pathway for Sex Pheromone Components Produced in a Plusiinae Moth, Plusia festucae

While many Plusiinae species commonly secrete (Z)-7-dodecenyl acetate (Z7-12:OAc) as a key pheromone component, female moths of the rice looper (Plusia festucae) exceptionally utilize (Z)-5-dodecenyl acetate (Z5-12:OAc) to communicate with their partners. GC–MS analysis of methyl esters derived from fatty acids included in the pheromone gland of P. festucae showed a series of esters monounsaturated at the ω7-position, i.e., (Z)-5-dodecenoate, (Z)-7-tetradecenoate, (Z)-9-hexadecenoate (Z9-16:Me), and (Z)-11-octadecenoate (Z11-18:Me). By topical application of D3-labled palmitic acid (16:Acid) and stearic acid (18:Acid) to the pheromone glands, similar amounts of D3-Z5-12:OAc were detected. The glands treated with D13-labeled monoenoic acids (Z9-16:Acid and Z11-18:Acid), which were custom-made by utilizing an acetylene coupling reaction with D13-1-bromohexane, also produced similar amounts of D13-Z5-12:OAc. These results suggested that Z5-12:OAc was biosynthesized by ω7-desaturase with low substrate specificity, which could introduce a double bond at the 9-position of a 16:Acid derivative and the 11-position of an 18:Acid derivative. Additional experiments with the glands pretreated with an inhibitor of chain elongation supported this speculation. Furthermore, a comparative study with another Plusiinae species (Chrysodeixis eriosoma) secreting Z7-12:OAc indicated that the β-oxidation systems of P. festucae and C. eriosoma were different

Improving the Cycle-life of Naphthoquinone-based Active Materials by Their Polymerization for Rechargeable Organic Batteries

AbstractTo increase the cycle-stability of rechargeable batteries using an organic positive-electrode material, we synthesized a polymer from a 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) skeleton, which potentially undergoes a four-electron transfer redox reaction. The polymeric material (PDHNQ) was synthesized by the condensation reaction between DHNQ and formaldehyde under acidic media conditions. The initial capacity of the electrode using the monomer (DHNQ), 193 mAh/g, quickly decayed to 56 mAh/g after 100 cycles. On the other hand, the electrode incorporating the prepared PDHNQ showed the higher initial discharge capacity of 256 mAh/g and a longer cycle-life, retaining about 133 mAh/g after 100 cycles

A Fully Implantable Wireless ECoG 128-Channel Recording Device for Human Brain–Machine Interfaces: W-HERBS

Brain–machine interfaces (BMIs) are promising devices that can be used as neuroprostheses by severely disabled individuals. Brain surface electroencephalograms (electrocorticograms, ECoGs) can provide input signals that can then be decoded to enable communication with others and to control intelligent prostheses and home electronics. However, conventional systems use wired ECoG recordings. Therefore, the development of wireless systems for clinical ECoG BMIs is a major goal in the field. We developed a fully implantable ECoG signal recording device for human ECoG BMI, i.e., a wireless human ECoG-based real-time BMI system (W-HERBS). In this system, three-dimensional (3D) high-density subdural multiple electrodes are fitted to the brain surface and ECoG measurement units record 128-channel (ch) ECoG signals at a sampling rate of 1 kHz. The units transfer data to the data and power management unit implanted subcutaneously in the abdomen through a subcutaneous stretchable spiral cable. The data and power management unit then communicates with a workstation outside the body and wirelessly receives 400 mW of power from an external wireless transmitter. The workstation records and analyzes the received data in the frequency domain and controls external devices based on analyses. We investigated the performance of the proposed system. We were able to use W-HERBS to detect sine waves with a 4.8-μV amplitude and a 60–200-Hz bandwidth from the ECoG BMIs. W-HERBS is the first fully implantable ECoG-based BMI system with more than 100 ch. It is capable of recording 128-ch subdural ECoG signals with sufficient input-referred noise (3 μVrms) and with an acceptable time delay (250 ms). The system contributes to the clinical application of high-performance BMIs and to experimental brain research

Dialkoxybenzoquinone-type Active Materials for Rechargeable Lithium Batteries: The Effect of the Alkoxy Group Length on the Cycle-stability

AbstractThe performance of 2,5-di-n-decyloxy-1,4-benzoquinone (DDBQ) as an active material for rechargeable lithium batteries was investigated. The prepared electrode in which DDBQ was incorporated showed an initial discharge capacity of 125 mAh/g(DDBQ) with an average voltage of 2.5V vs. Li+/Li. The obtained discharge capacity corresponds to a benzoquinone-based two-electron redox behavior. In the cycle-life test, the prepared DDBQ- electrode showed a relatively good performance; it maintained about 60% of the initial capacity after 20 cycles. The observed cycle-stability was compared to those of the other dialkoxybenzoquinones bearing shorter alkoxy chains, such as the methoxy, ethoxy, and propoxy groups. The correlation between the cycle-stability and the solubility in the electrolyte solvent was discussed