Dirigibles

The smoking salons of the Hindenburg and other hydrogen-filled dirigibles of Ihe 1930s were insulated with urea-formaldehyde polymer foams. The structure of this polymer is highly cross-linked, like that of Bakelite (Section 31.5). Propose a structure. 

Langevin MP and Chilowsky MC (1918) Precedes et appareils pour la production de signaux sous-marins diriges et pour la localization a distance d obstacles sous marins, French Patent No. 502913... 

For these comments, see J. A. Deluc, Introduction a la physique terrestre. . . precede de deux memoires sur la nouvelles theories chimiques (Paris Nyon, 1803) 151152, 163 quoting Fourcroy, on p. 164, that "la physique. . . doit preceder ses recherches, sans pouvoir diriger sa marche," in Antoine F. de Fourcroy, Systeme des connoissances chimiques, et de leurs application aux phenomenes de la nature et de / art, I (Paris Baudouin, Brumaire An IX). And for last quotation, ibid., 166. 

He got a Habilitation a diriger les recherches in 2008 and he is now developing his own project that consists of the elaboration of new hybrid metalloprotein catalysts for selective oxidation reactions, by insertion of metal cofactors into xylanases. He then studies their peroxidase, catalase, and monooxygenase activities, in particular in the selective oxidation of sulfides, alkanes, and alkenes. 

GEN.262. 1. Prigogine and J. Attali, Diriger dans un monde toujours plus complexe (How to manage in a more and more complex world), BMMA, 9/02/99, ULB. 

This biocatalytic method is therefore quite promising for the synthesis of complex molecules. Very recently, it was reported 1121] that HRP catalyzes the oxidation of 2-naphthols to l,l -binaphthyl-2,2 -diols with moderate enantiomeric excess (ee 38-64%) (Eq. 5). However, in view of the analytical techniques used, these data have to be questioned [167]. As shown recently, atrop-selective biaryl coupling can only be achieved by means of dirigent protein as chiral auxiliary [122]. 

Lighter-than-air balloons Hydrogen gas that is fighter than air was used to inflate some of the early free flight balloons and was used later in some dirigibles until the danger of explosions led to the use of helium as a substitute. 

Fig. 12.4 Biosynthetic pathway for lignans with 9,9 -oxygen including yatein and fxsdophyUo-toxin. DP dirigent protein, PLR pinoresinol/laiiciresinol reductase, PrR pinoresinol reductase, and SIRD secoisolariciresinol dehydrogenase...

DIrIgent protein Free radical capture and stereoselective coupling... 

Fig. 12.6 Enantioselective formation of pinoresinol. Forsythia intermedia dirigent protein mediates selective formation of (-l-)-pinoresinol...

Davin LB, Wang H-B, Crowell AL et al (1997) Stereoselective bimolecular phenoxy radical coupling by an auxiliary (dirigent) protein without an active center. Science 275 362-366... 

Xia Z-Q, Costa MA, Proctor J et al (2000) Dirigent-mediated podophyllotoxin biosynthesis in Liman jlavum and Podophyllum peltatum. Phytochemistry 55 537-549... 

JApplPhys 19, 563-82(1948) (Explosives with lined cavities) 28a) O. Nordzell, Teknik 1946, No 12 (Sweden) French transin in MAF 22, 247-56(1948) (Explosions a Effet Dirige) Charge creuse a coupe lie m tallique) 29) W.A. Noyes, Jr, "Science in WWII, Chemistry", Little,... 

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