My first five years in science.

Linus Pauling, a giant of modern chemistry, died on 19 August (see page 584 of last week's issue). What follows is an account, in his own words, of his first years as a research scientist.

Analysis of a hyperdeformed band of 152(66)Dy86 on the basis of a structure with two revolving clusters, each with a previously unrecognized two-tiered structure.

Analysis on the basis of the two-revolving-cluster model has been made of a cascade of 11 gamma-rays constituting a hyperdeformed band of 152(66)Dy86 (or possibly 153Dy) reported by Galindo-Uribarri et al. [Galindo-Uribarri, A., et al.

Analysis of the ground-state band and a closely related intercalated band of 235(92)U143 by the two-revolving-cluster model with consideration of symmetric and antisymmetric resonance of the two dissimilar clusters.

The reported ground-state band of 235(92)U143 extending from J = 7/2- to 51/2- is found to be two intercalated bands, one beginning with 7/2- and the other with 9/2-, each with DeltaJ = 2. Analysis by the two-resonating-cluster model leads to 3875 Da.fm2 for the moment of inertia for the first few levels, then increasing by centrifugal stretching.

Puzzling questions about excited superdeformed rotational bands of atomic nuclei are answered by the two-revolving-cluster model.

The two-revolving-cluster model provides explanations of several questions about excited superdeformed bands: restriction to the lanthanons and the Hg-Tl-Pb region and to the smaller values of the neutron number for each element, truncation of the gamma-ray cascades, differences in shape of the lanthanon and Hg-Tl-Pb bands, alignment of quantified spins, and the existence of pairs of bands with nearly identical gamma-ray sequences. A previously unrecognized kind of pairing (intercalation of gamma-ray values) is also reported and a discussion is given of the values of electric quadrupole moments.

Molecular structure of Ti8C12 and related complexes.

Application of valence-bond theory leads to the assignment to the molecule Ti8C12 of a cubic structure, point group Ohm3m, with 8 Ti at the cube corners, +/-(x x x, x, x x [symbol, see text]) where x = 1.78 A, and with 12 C in pairs in the cube faces, +/-(0 y z, [symbol, see text], 0, y z [symbol, see text]) where y = 1.78 A and z = 0.

Analysis of gamma-ray energies for 56 excited superdeformed rotational bands of nuclei of lanthanons La to Dy and of Hg, Tl, and Pb on the basis of the two-revolving-cluster model, with evaluation of moments of inertia and radii of revolution and assignment of nucleonic compositions to the clusters and the central sphere.

Analysis of the gamma-ray energies of 28 excited superdeformed bands of lanthanon nuclei by application of the two-revolving-cluster model yields the result that the central sphere for all 28 has the semimagic-magic composition p40n50, with the range p8n12 to p14n18 for the clusters and the radius of revolution increasing from 7.31 to 7.76 fm.

Effect of ascorbic acid on incidence of spontaneous mammary tumors and UV-light-induced skin tumors in mice.

Two large-scale studies of the effect of different amounts of L-ascorbic acid in the food on tumor-free survival have been conducted. One involved the incidence of spontaneous mammary tumors in RIII mice, with seven ascorbic acid and three control groups, 50 mice per group. With increasing ascorbic acid in the diet, there was a highly significant delay before appearance of the first tumor.

Analysis of the energy of the first four excited states of the ground-state rotational bands of the even-even nuclei from 6C8 to 56Ba90 with the model of a single cluster of nucleons revolving about a sphere.

The results of the analysis of the first four energy levels of the ground-state rotational bands of even-even nuclei from 6C8 to 56Ba90 on the basis of the revolving-cluster model are reported. Values of the nucleon number of the revolving cluster are assigned on the basis in part of the shell model and in part of the expectation that the corresponding values of the radius of revolution would change only slightly from one energy level to an adjacent level or from one nucleus to an adjacent nucleus. The values of the radius of revolution are found to change gradually from about 5 to 6 fm for the lighter nuclei to 7 to 8 fm for the heavier nuclei in the sequence studied.

The structure of K3C60 and the mechanism of superconductivity.

Analysis of the interatomic distances in the superconducting substance K3C60 indicates that each of the K atoms in tetrahedral interstices between C60 spheres accepts three electrons from C60, thus becoming quadricovalent; its four bonds resonate among the 24 adjacent carbon atoms to give a strong framework in which the negative charges are localized on these K atoms. The electric current is carried by the motion of positive charges (holes) through the network of C60 spheres and the K atoms in octahedral holes. Superconductivity is favored by the localization of the negative charges on the tetrahedral K atoms and their noninvolvement in valence-bond resonance, decreasing the rate of mutual extinction of electrons and holes.

Analysis of pulsed-neutron powder diffraction patterns of the icosahedral quasicrystals Pd3Siu and AlCuLiMg (three alloys) as twinned cubic crystals with large units.

The low-Q peaks on three pulsed-neutron powder patterns (total, U differential, and Pd differential) of the icosahedral quasicrystal Pd3SiU have been indexed on the basis of an assumed cubic structure of the crystals that by icosahedral twinning form the quasicrystal. The primitive unit cube is found to have edge length 56.20 A and to contain approximately 12,100 atoms.

Analysis of the energy of the first four excited states of the ground- state rotational bands of the even-even lanthanon nuclei (58Ce to 70Yb) with the model of a single cluster of nucleons revolving about a sphere.

Analysis of the first four excited energy levels of the ground-state rotational bands of 82 nuclei (isotopes of the seven even-even lanthanons from 58Ce to 70Yb) has provided values of the radius of revolution of a single cluster about a sphere in each nucleus. The number of nucleons m in each cluster is taken to be 2 for neutron number N = 82 in each case for the first excited state, usually increasing by 2 with change in Z or N by +/-2, but sometimes changing by 0 or by 4 or more. The radius of revolution R decreases to a minimum (about 6.

Transition from one revolving cluster to two revolving clusters in the ground-state rotational bands of nuclei in the lanthanon region.

Whereas 234(92)U142 and other actinon nuclei have ground-state bands that indicate that each nucleus consists of a sphere and a single revolving cluster with constant composition and with only a steady increase in the moment of inertia with increase in J, the angular-momentum quantum number, many of the lanthanon ground-state bands show discontinuities, usually with an initial slightly or strongly curved segment followed by one or two nearly straight segments. The transition to nearly straight segments is interpreted as a change in structure from one revolving cluster to two revolving clusters. The proton-neutron compositions of the clusters and the central sphere are assigned, leading to values of the radius of revolution.

Immunological evidence for the accumulation of lipoprotein(a) in the atherosclerotic lesion of the hypoascorbemic guinea pig.

Lipoprotein(a) [Lp(a)] is an extremely atherogenic lipoprotein. Lp(a) has been found in the plasma of humans and other primates, but until now only in a few other species. The mechanism by which it exerts its atherogenicity is still poorly understood.

Evidence from electron micrographs that icosahedral quasicrystals are icosahedral twins of cubic crystals.

An analysis of electron micrographs of Al5Mn quasicrystals obtained by rapidly cooling a molten alloy with composition Al17Mn and removing the Al matrix by electrosolution, revealing aggregates of 20 microcrystals at the corners of a pentagonal dodecahedron, supports the proposal that these microcrystals are cubic crystals twinned about an icosahedral seed, with each cubic microcrystal sharing a threefold axis and three symmetry planes with the seed.

Suppression of human immunodeficiency virus replication by ascorbate in chronically and acutely infected cells.

We have studied the action of ascorbate (vitamin C) on human immunodeficiency virus type 1 (HIV-1), the etiological agent clinically associated with AIDS. We report the suppression of virus production and cell fusion in HIV-infected T-lymphocytic cell lines grown in the presence of nontoxic concentrations of ascorbate. In chronically infected cells expressing HIV at peak levels, ascorbate reduced the levels of extracellular reverse transcriptase (RT) activity (by greater than 99%) and of p24 antigen (by 90%) in the culture supernatant.

Hypothesis: lipoprotein(a) is a surrogate for ascorbate.

The concept that lipoprotein(a) [Lp(a)] is a surrogate for ascorbate is suggested by the fact that this lipoprotein is found generally in the blood of primates and the guinea pig, which have lost the ability to synthesize ascorbate, but only rarely in the blood of other animals. Properties of Lp(a) that are shared with ascorbate, in accordance with this hypothesis, are the acceleration of wound healing and other cell-repair mechanisms, the strengthening of the extracellular matrix (e.g.

Regularities in the sequences of the number of nucleons in the revolving clusters for the ground-state energy bands of the even-even nuclei with neutron number equal to or greater than 126.

Values of m, the number of nucleons in the revolving cluster, and of R, the radius of revolution of the cluster about the center of mass of the spherical part of the nucleus, are calculated from the observed values of the energy for the ground-state bands of all nuclei with neutron number N >/= 126 on the basis of the assumptions (i) that both m and R change in a reasonable way with increase in the angular momentum quantum number J and with change in the proton number Z and the neutron number N, (ii) that m is usually an even integer, (iii) that certain clusters are especially stable, and (iv) that there is a special stability of the doubly magic sphere p82n126.

Determination of the crystal structure and composition of Li6Be4OH12 by the stochastic method.

Because of the failure to find a structure for LiBeH3 with a face-centered unit cube with edge 5.09 A, the x-ray powder pattern has been reindexed for a body-centered unit cube with edge 7.24 A.

Icosahedral and decagonal quasicrystals of intermetallic compounds are multiple twins of cubic or orthorhombic crystals composed of very large atomic complexes with icosahedral point-group symmetry in cubic close packing or body-centered packing: Structure of decagonal Al(6)Pd.

A doubly icosahedral complex involves roughly spherical clusters of atoms with icosahedral point-group symmetry, which are themselves, in parallel orientation, icosahedrally packed. These complexes may form cubic crystallites; three structures of this sort have been identified. Analysis of electron diffraction photographs of the decagonal quasicrystal Al(6)Pd has led to its description as involving pentagonal twinning of an orthorhombic crystal with a = 51.

Icosahedral quasicrystals of intermetallic compounds are icosahedral twins of cubic crystals of three kinds, consisting of large (about 5000 atoms) icosahedral complexes in either a cubic body-centered or a cubic face-centered arrangement or smaller (about 1350 atoms) icosahedral complexes in the beta-tungsten arrangement.

The twofold-axis electron-diffraction photographs of icosahedral quasicrystals are of three kinds, reflecting three different structures of the cubic crystals that by icosahedral twinning form the quasicrystals. The first kind, represented by Al(13)Cu(4)Fe(3), contains two very large icosahedral complexes, each of about 4680 atoms, in the body-centered arrangement, with six smaller icosahedral complexes (104 atoms each) in the principal interstices. The second kind, represented by Al(5)Mn, contains four of the very large complexes in the face-centered arrangement (cubic close packing), with four of the smaller clusters in the interstices.