Geranial: the alarm pheromone in the nymphal stage of the oribatid mite,Nothrus palustris

The presence of an alarm pheromone was demonstrated in the deutonymphal stage of the oribatid mite, Nothrus palustris (C. L. Koch). The active principle was identified as 3,7-dimethyl-(E)-2,6-octadienal, geranial, and was shown to be active at doses of 10–100 ng. This is the first such pheromone identified in oribatid mites.     

Microphase separated structure,surface composition and blood compatibility of segmented poly(urethaneureas) with various soft segment components

Properties, surface composition, and blood compatibility of segmented poly(urethaneureas) (SPUU's) with various soft segment components were investigated. The microphase separated structure between hard and soft segments improved with an increase in molecular weight ($\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$) of polyether diol in soft segment. The amount of absorbed water depended on the nature of the polyether component. X-ray photoelectron spectra of the surface of SPUU revealed that the surface composition depended on $\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$ and surface free energy of polyether component. Blood compatibility of SPUU depended on the state of microphase separated structure and surface composition.     

n- and p-Channel field-effect transistors based on diquinoxalinoTTF derivatives

Three new quinoxalinoTTF derivatives with methyl, trifluoromethyl and fluoro groups were synthesized and characterized by UV–vis absorption spectroscopy, differential scanning calorimetry, X-ray single crystal analysis, X-ray diffraction, and field-effect transistor (FET) characteristics. All of them have π-stacking structures in the single crystals. The quinoxalinoTTF derivative with trifluoromethyl groups exhibited an n-type FET, which is a rare example of n-channel FETs based on TTF derivatives. The highest electron mobility is 0.01 cm² V^?1 s. The FET polarity was converted to p-channel from n-channel by replacing the trifluoromethyl groups with methyl groups. The hole mobility is as high as 0.2 cm² V^?1 s. In contrast, the fluoro substituted derivative did not show FET properties due to the poorly ordered molecular arrangement.     

Dynamic fluorescence quenching precedent to thermally-induced phase separation of poly(ethoxyethyl vinyl ether) aqueous solution

We focused on the stage preceding the thermally-induced phase separation of aqueous solution of poly(ethoxyethyl vinyl ether) (PEVE). Previously, we observed an interesting dynamic quenching just below the phase separation temperature. The dynamic fluorescence quenching disappeared by addition of a surfactant. In systems without the phase separation of both the hexane solution of PEVE and the PEVE bulk, the fluorescence lifetime decreased monotonically with the increase of temperature. These results indicated that the marked decrease is due to the dynamic quenching by the collision between the fluorescent probe and the PEVE segment induced by the thermal fluctuation precedent to the phase separation.     

Mass Spectrometric Analysis of Sphingomyelin with N-α-Hydroxy Fatty Acyl Residue in Mouse Tissues

Sphingomyelin (SM) with N-α-hydroxy fatty acyl residues (hSM) has been shown to occur in mammalian skin and digestive epithelia. However, the metabolism and physiological relevance of this characteristic SM species have not been fully elucidated yet. Here, we show methods for mass spectrometric characterization and quantification of hSM. The hSM in mouse skin was isolated by TLC. The hydroxy hexadecanoyl residue was confirmed by electron impact ionization-induced fragmentation in gas chromatography–mass spectrometry. Mass shift analysis of acetylated hSM by time of flight mass spectrometry revealed the number of hydroxyl groups in the molecule. After correcting the difference in detection efficacy, hSM in mouse skin and intestinal mucosa were quantified by liquid chromatography–tandem mass spectrometry, and found to be 16.5 ± 2.0 and 0.8 ± 0.4 nmol/μmol phospholipid, respectively. The methods described here are applicable to biological experiments on hSM in epithelia of the body surface and digestive tract.     

Structure--activity relationships in human interleukin-1{alpha}: identification of key residues for expression of biological activities

To identify the sites important for the different biologicalactivities of human interleukin-l (hIL-1), 56 single-amino acid-substitutedmutants of hIL-l were produced in Escherichia coli using site-directedmutagenesis, and were examined for their biological activitiessuch as mouse lymphocyte activating factor activity (LAF activity),cytostatic activity against human melanoma cells A-375 (A375activity) and prostaglandin E2 (PGE2) inducing activity in humanosteosarcoma cells MG-63 (PEI activity). Two amino acid residues,Asp26 and Asp151, were found to be important for these activities.The replacement of Asp26 by Val caused a decrease in LAF andA375 activities by one or two orders of magnitude and a slightdecrease in A375 activity. The Tyr or Phe substitution for Asp151caused decreases in LAF and A375 activities by one or two ordersof magnitude and complete loss of PEI activity. The change fromAsp151 to Lys or Arg resulted in marked decrease in LAF activityand complete loss of A375 and PEI activities. Since Asp26 andAsp151 are close to each other in the three-dimensional structure,the region involving these amino acids seems to be importantfor the biological activities of hIL-1.     

Preparation of cellulose-based ionic porous material compatibilized with polymeric ionic liquid

Cellulose-based ionic porous material compatibilized with polymeric ionic liquid was prepared by means of templating technique using oil/ionic liquid emulsion in the presence of sorbitane monooleate. In situ polymerization of a mixture of polymerizable ionic liquids, 1-(3-acryloyloxypropyl)-3-methylimidazolium and 1-(3-acryloyloxypropyl)-3-vinylimidazolium bromides was first performed in a solution of cellulose in a solvent of an ionic liquid, 1-butyl-3-methylimidazolium chloride. The sonication of the mixture coexisting with corn oil and sorbitan monooleate, followed by the successive treatment with methanol, acetone, and hexane gave the porous material. The material thus obtained was characterized by the FT-IR, TGA, XRD, and SEM measurements. The SEM images of the material showed the morphology of the porosity with the pore sizes of around 0.15–1.3 μm accompanied with the smaller sizes of 30–70 nm.     

Enhancement of oxygen reduction activity of nanoshell carbons by introducing nitrogen atoms from metal phthalocyanines

Nanoshell carbon is a type of catalytically grown nanocarbon with a hollow, round, shell-like structure, with a diameter in the range of approximately 20-50 nm. It has been shown to possess the electrocatalytic activity for oxygen reduction reaction (ORR) and is also expected to be a non-Pt catalyst for polymer electrolyte fuel cells. This paper reports the synergetic enhancement of the ORR activity of nanoshell carbons caused by the coexistence of nitrogen atoms. The nanoshell carbons were prepared by the carbonization of furan resin in the presence of acetylacetonates (AAs) and of phthalocyanines (Pcs), which contained Fe, Co, and Ni. The Pc-derived nanoshells (MP-T series; M = Co or Fe, T = carbonization temperature) showed higher ORR activities than the AA-derived nanoshells (MA-T series; M = Co or Fe, T = carbonization temperature) when the same metal elements were employed. An XPS study revealed that nitrogen species were introduced to the surface of the nanoshells when Pcs were used as the nanoshell-forming catalysts, and that no metal species remained on the nanoshells. Principally, the ORR activity of the carbons was governed by the presence of the nanoshells and further enhancement could be achieved by the introduction of nitrogen atoms. 0.78 V of OCV and 0.21 W cm⁻² of the maximum power density were observed for a fuel cell whose MEA consisted of 3CoP1000 cathode and a commercial Pt/C anode, when it was operated at 80 °C under a pressurized condition of 0.35 MPa.     

Absorption Dynamics in All-Optical Switch Based on Intersubband Transition in InGaAs–AlAs–AlAsSb Coupled Quantum Wells

We developed a pigtailed fiber module including an intersubband transition all-optical switch using InGaAs-AlAs-AlAsSb coupled double quantum wells and studied the absorption saturation dynamics. An increased extinction ratio was obtained by optimizing the delay time between control and signal pulses due to the reduced effect of two-photon absorption. An extinction ratio of 10 dB was obtained for a fiber input pulse energy of 16 pJ (200-fs pulsewidth). The absorption recovery time varied from 600 fs to 2 ps depending on the control pulse energy