Chemical Vapor Detection Using a Reconstituted Insect Olfactory Receptor Complex

The sensing of vapor odorants is highly demanded in the field of life and medical sciences. Although olfactory receptors (ORs) have potentials to recognize volatile organic compounds, the interaction of ORs, chemical vapors, and peptide components in olfactory mucus has yet to be analyzed to develop OR‐based sensors. A bioinspired electrophysiology technique is shown to record the response of reconstituted insect ORs to chemical vapors. To mimic the interface between ORs and olfactory mucus, OR expressing spheroids were loaded into a hydrogel microchamber array. A negative extracellular field potential shift of spheroids was successfully observed by the stimulation of their vapor cognate ligand. Importantly, the ligand repertoire of the OR of malaria vector mosquito examined by this method differed from that of in vivo studies. Our method is useful to develop protein‐based gas sensing techniques and to examine the binding of ORs and chemical vapors.     

Increased phosphatidylcholine (16:0/16:0) in the folliculus lymphaticus of Warthin tumor

Warthin tumor (War-T), the second most common benign salivary gland tumor, consists mainly of neoplastic epithelium and lymphoid stroma. Some proteins and genes thought to be involved in War-T were evaluated by molecular biology and immunology. However, lipids as an important component of many tumor cells have not been well studied in War-T. To elucidate the molecular biology and pathogenesis of War-T, we investigated the visualized distribution of phosphatidylcholines (PCs) by imaging mass spectrometry (IMS). In our IMS analysis of a typical case, 10 signals were significantly different in intensity (p?+ (m/z 772.5), [PC (16:0/20:4)?+?K]⁺ (m/z 820.5), [PC (16:0/20:3)?+?K]⁺ (m/z 822.5), [PC (18:2/20:4)?+?K]⁺ (m/z 844.5), and [PC (18:0/20:5)?+?K]⁺ (m/z 846.5). PC (16:0/16:0) was increased specifically in the folliculus lymphaticus of War-T lymphoid stroma, suggesting a different metabolism. Localization of PC (16:0/16:0) might reflect inflammation activity participating in the pathogenesis of War-T. Thus, our IMS analysis revealed the profile of PCs specific to the War-T region. The molecules identified in our study provide important information for further studies of War-T pathogenesis.     

Pyrochemical treatment of spent nitride fuels for MA transmutation

Nitride fuels have several advantages including high thermal conductivity and high metal density(like metallic fuels) and high melting point and isotropic crystal structure(like oxide fuels). Since the late 1990 s, the partitioning and transmutation of minor actinides(MA) has been studied to decrease the long-term radio-toxicity of high-level waste and to mitigate the burden of final disposal. Japan Atomic Energy Agency(JAEA) has proposed a dedicated transmutation cycle using an accelerator-driven system(ADS) with nitride fuels containing MA. The nitride fuel cycle we have developed includes a pyrochemical process. Our focus is on the electrolysis of nitride fuels and their refabrication from the recovered actinides; other processes are similar to the technology for metal fuel treatment and have been studied elsewhere. Here, we summarize our activity on the development of the pyrochemical treatment of spent nitride fuels.     

Dicyanoketene Ethylene Acetal as a Mild and Efficient Catalyst for Tetrahydropyranylation of Alcohols

Alcohols can react with 3,4-dihydro-2H-pyran in the presence of a catalytic amount of dicyanoketene ethylene acetal under neutral conditions to afford the corresponding tetrahydropyranyl ethers in good yields.     

Stabilization of Bicontinuous Cubic Phase and Its Two-Sided Nature Produced by Use of Siloxane Tails and Introduction of Molecular Nonsymmetry

A recent intriguing finding that a helical network arrangement forms the bicontinuous cubic phase is attracting great attention for the possibility of new routes to asymmetric synthesis by achiral molecules. However, the design of the molecular structure for the cubic phase is still unrevealed. In this work, a nonsymmetric core molecule with larger naphthalene and smaller benzene moieties at each side of the central linkage and the same disiloxanyldecyloxy terminal at both terminals is shown to be the first example of molecule forming both single-layered and double-layered core assembly modes in the Ia3d phase as a single molecule system. The molecule forms the former mode at high temperatures as a thermodynamically stable phase, similarly to the symmetric naphthalene core system, whereas, on cooling below a temperature (∼350 K), a metastable Ia3d phase forms a double-layered core state down to room temperature, which is common to the benzene core system. As another effect of the nonsymmetric core, the cubic phase is maintained at room temperature for more than 100 days with slight distortion. Infrared spectral studies and quantum chemical calculations suggested the easy transformation between the two core assembly modes. The core nonsymmetry can be a versatile fine-tuning of the core assembly mode and phase stability for the cubic phase molecules.     

Determination of micro-amounts of sulphur in organic compounds by combustion and reduction

Summary A rapid sensitive method for the determination of microgram amounts of sulphur is described. Sulphur (free or combined) in organic substances is oxidised completely in an oxygen atmosphere over a platinum gauze catalyst after a preliminary incomplete combustion in air. The oxides of sulphur are collected on silver gauze at 550°. The oxygen is purged from the apparatus with a stream of nitrogen and then the silver sulphate is heated in a stream of hydrogen to yield hydrogen sulphide which is collected in an alkaline zinc acetate solution and subsequently determined spectrophotometrically by the methylene blue method.The recovery of sulphur in the range 5–40g was 100±5%. The method takes less than 25 minutes for a single determination and is reliable for the determination of as little as1 g of sulphur in all types of organic compounds. Solid, liquid, or gaseous samples may be used.

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Zusammenfassung Eine schnelle, empfindliche Methode zur Bestimmung von Mikrogrammmengen Schwefel wurde beschrieben. Freier oder gebundener Schwefel in organischem Material wird nach unvollständiger Verbrennung in Luft in Sauerstoffatmosphäre über einem Platindrahtnetz vollständig oxydiert. Die Schwefeloxide werden auf Silberdrahtnetz bei 550° gebunden. Der Sauerstoff wird mit Stickstoff aus der Apparatur gespült und dann das Silbersulfat im Wasserstoffstrom zu Schwefelwasserstoff reduziert, der in alkalischem Zinkacetat aufgefangen und dann nach der Methylenblaumethode spektrophotometrisch bestimmt wird.In der Größenordnung zwischen 5 und 10g wird der Schwefel zu 100±5% erfaßt. Eine Einzelbestimmung dauert weniger als 25 Minuten. Für alle Arten organischer Verbindungen, ob fest, flüssig oder gasförmig, eignet sich das Verfahren für die Bestimmung von 1g Schwefel und darüber.

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Résumé On décrit une méthode rapide et sensible pour le dosage de quantités de soufre de l'ordre du microgramme. Le soufre (libre ou combiné) dans les substances organiques est oxydé complètement en atmosphère d'oxygène sur une toile de platine, catalyseur, après une combustion préliminaire incomplète dans l'air. Les oxydes du soufre sont rassemblés sur une toile d'argent à 550°. On purge l'appareil de l'oxygène par un courant d'azote puis le sulfate d'argent est chauffé dans un courant d'hydrogène en donnant de l'hydrogène sulfuré qui est rassemblé dans une solution alcaline d'acétate de zinc et dosé ensuite par spectrophotométrie par la méthode au bleu de méthylène.La récupération du soufre entre 5 et 40g atteint 100±5%. La méthode demande moins de 25 minutes pour un dosage individuel et reste valable pour les teneurs descendant jusqu'à 1g de soufre dans les composés organiques de toutes natures. On peut utiliser des échantillons solides, liquides ou gazeux.

     

Facile and rapid entry to functionalized and optically active pyrans from tartaric acid by way of 6,8-dioxabicyclo[3.2.1]Octanes. Application to the synthesis of (−)-(6s,1′s)-pestalotin

Optically active 7-exo-substituted-3-p-tosyl-6,8-dioxabicyclo[3.2.1]-octanes prepared from (+)-(R,R)-diethyl tartrate in four or five steps sequence effectively utilizing the inherent C₂ symmetry of tartrate, underwent acetolysis to lead to the new type of functionalized and optically active 3,4-dihydro-2Hpyrans in high yields. An application to the unambiguous synthesis of (-)-(6S,1′S)-pestalotin is reported.     

Multivalent macrocyclic hosts: histone surface recognition, guest binding, and delivery by cyclophane-based resorcinarene oligomers

As a new class of host for both specific proteins and hydrophobic molecular guests, cyclophane-based resorcinarene oligomers were designed on the basis of a molecular design that allows the assembly of four or 12 anionic resorcinarenes on a cyclophane skeleton. We prepared a cyclophane-based resorcinarene tetramer (4), constructed with a tetraaza[6.1.6.1]-paracyclophane skeleton and four resorcinarenes bearing heptacarboxylic acid residues that connect to the macrocycle through amide linkages. In addition, we prepared an extended analogical dodecamer (12), which was constructed with a pentakis(cyclophane) skeleton and 12 resorcinarenes. The cyclophane-based resorcinarene oligomers exhibited potent recognition capabilities toward histone, a small basic protein of eukaryotic chromatins. The binding constants (K) of cyclophane-based resorcinarene tetramer 4 and dodecamer 12 with histone were determined to be 1.3x107 and 8.4x107 M-1, respectively, by means of surface plasmon resonance measurements. The K values of 4 and 12 with histone were 31- and 200-fold larger than that of an untethered reference resorcinarene, reflecting the multivalency effects in resorcinarenes. In addition to that, cyclophane-based resorcinarene tetramer 4 and dodecamer 12 captured hydrophobic guests such as 6-p-toluidinonaphthalene-2-sulfonate, with respective binding constants of 2.4x103 and 2.5x104 M-1 in an aqueous HEPES buffer as evaluated by fluorescence spectroscopy. Furthermore, the resorcinarene oligomers were also found to act as guest carriers from the bulk aqueous phase to histone surfaces, as confirmed by fluorescence spectroscopy.