Lead-acid cell skeleton

The ex situ method, pioneered by Hubbard [1] and Ross [56], entails electrode preparation in UHV, clean transfer of the specimen from UHV into an electrochemical cell and transfer back to UHV for postelectrochemical reaction analysis. The methodology was developed to study the stability of Pt-skin and 3d elements in sputtered surfaces. For this purpose, we restrict our analysis to the polycrystalline PtjFe surface, which is discussed in Sect. 2.1. As summarized in Fig. 3.1b, LEIS spectra indicate that after exposing this alloy to an electrochemical environment Fe surface atoms dissolve from the near-surface layers leading to a first atomic layer composed entirely of Pt [21]. For the remaining surface, which consists of only Pt atoms after dissolution of the alloying component, we employ the term Pt-skeleton structure. The conclusions drawn from these experiments are equally valid for all sputtered PtjM alloys i.e., whenever 3d transition metal atoms are exposed to acidic environments, nonplatinum atoms dissolve leading to the formation of Pt-skeleton surfaces. 

In mammalian liver parenchyma cells, the synthesis of the steroid skeleton which was described on p. 236 is extended by acquisition of an enzyme system leading to the production of the substances known as bile acids. In man, this s3mthesis yields cholic acid, desoxycholic acid and chenodesoxycholic acid. The hepatic parenchyma in mammals also conjugates these bile acids with taurine and with glycine. 

Porco and co-workers s kibdelone C synthesis makes use of an unusual 671-electrocyclization in the key step that assembles the hexacyclic skeleton of the natural product. The kibdelones are polyketide-derived natural products that were isolated and characterized by Capon and co-workers from Kibdelosporangiton sp., an Australian soil actinomy-cete. - The interest in these compounds is a result of their potent activity against leukemia (SR) and renal cancer cells (SN12C). Selective hydrolysis of the methyl ester function in 69 (Scheme 19.19) was followed by heating of the derived carboxylic acid with cyanuric chloride and pyridine in dichloromethane, leading to 73 in 39% overall yield for... 

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