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161.

In the quadri–dimensional space–time, the variation of Hamilton’s action is a powerful tool to study the process equations for conservative fluid media. In this framework, Hamilton’s principle allows to obtain equation of motions, equation of energy but also Rankine–Hugoniot conditions. The variational method may be a versatile key to obtain the shock-wave conditions for complex media when the equations of processes are not expressed by linear or quasi-linear differential equations.

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The thermal stability of the monodiazohydroborate NMe4[1‐N2B10H9] was studied by thermogravimetric analysis. Under two different atmospheres (air and argon), the thermal decomposition starts at a temperature between 140 and 160 °C. The decomposition residue obtained was separated on a silica gel column. 11B NMR, IR and electrospray mass spectroscopy analyses of the different fractions separated showed that the above decomposition produces (NMe4)2[B20H18] as major product (90%), along with smaller amounts of residual NMe4[1‐N2B10H9] (5%), (NMe4)2[B12H12] and boric acid. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
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A stereoselective synthesis of unknown spirobenzodihydropyrancyclohexanes is described starting from arylcyclohexenes alkylated and cyclized via a coumarin intermediate and leading to new amino derivatives which are rigid analogs of dopamine.  相似文献   
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Summary Today, more than 40 protein amino acid (AA) sequences of membrane receptors coupled to guanine nucleotide binding proteins (G-proteins) are available. For those working in the field of medicinal chemistry, these sequences present a new type of information that should be taken into consideration. To make maximal use of sequence data it is essential to be able to compare different protein sequences in a similar way to that used for small molecules. A prerequisite, however, is the availability of a processing environment that enables one to handle sequences in an easy way, both by hand and by computer. In order to meet these ends, the package CGEMA (Colour Graphics Editor for Multiple Alignment) was developed in our laboratory. The programme uses a user-definable colour coding for the different AAs. Sequences can be aligned by hand or by computer, using VGAP, and both approaches can be combined. VGAP is a novel in-house written alignment programme with a variable gap penalty that also handles consecutive alignments using one sequence as a probe. In addition, secondary structure prediction tools are available.From the 20 protein sequences, available for the muscarinic acetylcholine receptor, 13 different sequences were selected, covering the subtypes m1 to m5. By comparing the sequences, two major groups are revealed that correspond to those found by considering the transducing system coupled to the various receptor subtypes. Different parts of the protein sequences are identified as characterizing the subtype and binding the ligands, respectively.  相似文献   
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