Optimal shape design for packaging containing heating elements by inverse heat transfer method

The present study is concerned with the determination of the optimal shape for a package containing multiple heating elements. The optimization tool has been developed based on the inverse heat transfer (IHT) approach, incorporating a direct problem solver, a numerical grid generator, a direct-differentiation sensitivity analyzer, and the conjugate gradient method. Shape design that leads to a specified outer surface temperature distribution is predicted by the approach. In this study, the effects of internal heat generation on optimal shapes of the packagings have also been evaluated. Several practical cases with various imbedded heating elements and thermal conditions are studied. Results show that the approach provides an efficient computer-aided design scheme for the shape profile determination.     

The Removal of S-Cysteine Protection by Means of 2-Pyridine Sulfenyl Chloride and the Subsequent Formation of Disulfide Bonds. Preliminary communication

2-Pyridine sulfenyl chloride (PS-Cl) is a useful reagent for simultaneously deprotecting and activating the mercapto-group of cysteine and of cysteine-peptides preliminary to disufide-bond formation. The S-protecting groups that are amenable to this reaction include trityl, diphenylmethyl, acetamidomethyl, t-butyl, and t-butylsulfenyl.     

Structures and Bioactivities of Steroidal Saponins Isolated from the Genera Dracaena and Sansevieria

The species Dracaena and Sansevieria, that are well-known for different uses in traditional medicines and as indoor ornamental plants with air purifying property, are rich sources of bioactive secondary metabolites. In fact, a wide variety of phytochemical constituents have been isolated so far from about seventeen species. This paper has reviewed the literature of about 180 steroidal saponins, isolated from Dracaena and Sansevieria species, as a basis for further studies. Saponins are among the most characteristic metabolites isolated from the two genera. They show a great variety in structural motifs and a wide range of biological activities, including anti-inflammatory, anti-microbial, anti-proliferative effects and, in most case, remarkable cytotoxic properties.     

Synthesis of L-Propargylglycine and Derivatives

The chemical synthesis of L -propargylglycine (L -Pra) and of various derivatives is described. The new amino acid is a starting material for carboranylalanine (Car) and for tritiated norleucine.     

L-o-Carboranylalanine,a Boron Analogue of Phenylalanine

The synthesis of a new, boron-containing analogue of phenylalanine is described. Carboranylalanine (Car) carries a 1,2-carborane cage in place of the benzene ring of phenylalanine. It is obtained by the reaction of derivatives of propargylglycine with decaborane. Possibilities of practical application derive from the facile neutron activation of boron nuclei with mass number 10.     

Melanotropin Receptors I. Synthesis and Biological Activity of Nα-(5-Bromovaleryl)-Nα-deacetyl-α-melanotropin

Chemical synthesis and biological activities of a new α-melanotropin derivative are described. N^α-(5-Bromovaleryl)-N^α-deacetyl-α-melanotropin contains the 5-bromopentanoyl group as a chemical ‘handle’ in place of the acetyl group of the natural hormone. The synthesis involved a new protected intermediate which allowed the selective deprotection of either the N^α or N^α amino group. The title compound reacted with sodium thiosulfate to give N^α-deacetyl-N^α-(5-(sulfothio)valeryl)-α-melanotropin, a key intermediate for the preparation of tobaccomosaic virus/α-melanotropin disulfide conjugates. As a basis for the study of the conjugates, biological activities of the title compound on Cloudman S-91 mouse melanoma cell cultures (tyrosinase stimulation, binding, and cyclic AMP accumulation) were determined. They proved to be quite similar to the corresponding α-melanotropin activities. Differences in bindings may be explained by stronger hydrophobic interaction of the new derivative with the lipid phase of the target cell membranes.     

Laser produced acoustic waves transverse to the direction of laser propagation in SF6

It was found by the Michelson interferometric method that an absorption of 10.6 μm laser pulse generates an acoustic wave transverse to the direction of laser propagation in SF₆.