CHLORPROMAZINE INGESTION INHIBITS UV-INDUCED SKIN CARCINOGENESIS

Abstract Chlorpromazine (0.01% in drinking water) inhibits the induction of skin cancer by sunlamp irradiation of hairless mice. This inhibition is partially reversed by a single injection of ethyl nitrosourea at birth.     

Projection-Reconstruction Spectroscopic Imaging forB0Field Plotting and Shimming without Pulsed Gradients

Shimming is important. Noniterative methods are desirable. Such methods exist for shimming a spectrometer with pulsed field gradients, generally based on field maps made by spin-warp Fourier imaging. For spectrometers with no pulsed gradients (or for cases whereT₂is too short to permit echo imaging), an alternative method is presented: projection-reconstruction spectroscopic imaging, which can be accomplished using only the shim coils of a conventional spectrometer. Images so acquired can be used to map the field, even in the presence of multiple spectral components. Noniterative optimization of the axial shims of a GN-300 spectrometer is demonstrated using 1D + 1D spectroscopic images. Prospects for extending the technique to include the radial shims using 3D + 1D spectroscopic images are discussed.     

X-PLORing extraribosomal peptide folding during synthesis

An X-PLOR scheme for imitating the action of ribosomes in aiding synthesizing peptides to find their ultimate conformations is introduced. The scheme is tested with an example from the Delta-Sleep-Inducing-Peptide mutant family. © 1994 by John Wiley & Sons, Inc.     

Nonnegative matrices with power invariant zero patterns

If A is a nonsingular M-matrix, the elements of the sequence {A^?k} all have the same zero pattern. Using the Drazin inverse, we show that a similar zero pattern invariance property holds for a class of matrices which is larger than the generalized M-matrices.     

Fluoroketenes VIII. Adducts of perfluoromethacryloyl fluoride with unsaturated molecules. N-alkyl-bis(trifluoromethyl)ketenimines

Perfluoromethacryloyl fluoride has been found to yield predominantly 1,4 cyclo-adducts with olefins, isocyanates, nitriles and ketenes. With olefins and isocyanates, 1,2 cyclo-adducts and open-chain adducts are also formed, and evidence is presented to indicate that such adducts are obtained via dipolar intermediates. A new synthesis of N-alkyl-bis(trifluoromethyl)ketenimines is also reported.     

A theoretical investigation of the rotational barriers of peroxyformic acid

The internal rotational barriers in peroxyformic acid have been studied employing ab initio MO calculations. The C-O and O-O rotational barriers were calculated to be 7.68 and 1.04 $\text{kcal}\text{mol}$, respectively. The relatively low O-O rotational barrier is attributed to a balance between electron repulsion and hydrogen bonding in the syn chelated conformer.     

Crystal and molecular structure of tricyclohexylphosphineethylidenenickel tricarbonyl: a reaction product of Ni(CO)4 and (C6H11)3P=(CH)CH3

The structure of tricyclohexylphosphineethylidenenickel tricarbonyl, (C₆H₁₁)₃P(CH)CH₃.Ni(CO)₃, has been determined by direct methods from 5858 automatic diffractometer data, and refined anisotropically to a finalR value of 0·094 (including hydrogen atoms). The crystals are monoclinic, space group P2₁/n, with a=10·670(1), b=13·879(2), c=16·222(2) Å, =91·80(1)° and z=4. The main feature of the structure determination is the confirmation of the predicted arrangement of the ligand with its bonding to nickel via the secondary carbon of ylid-ligand. This carbon and the nickel atoms show approximate tetrahedral geometry. There seems to be no direct interaction between phosphorus and nickel (closest approach distance is 3·30 Å). The nickel-carbon distance (2·10 Å) is longer than any other Ni-C(sp³) distance previously reported.No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission of Plenum Publishing Company Limited.National Lending Library Supplementary Publication No. 60056 contains 29 pages of structure factor tables on 1 microfiche.