Relationships necessary for ring stability are derived between the self-focusing forces of an electron ring and the magnetic field gradient defocusing forces present near and just subsequent to the start of ring acceleration.

Di-tertiarybutylnitroxide (DTBN), which they have tried to use as a trapping agent to identify the species giving rise to the photo-induced EPR signals in photosynthetic materials, functions as a Hill reagent with spinach chloroplasts. Evidence is presented which indicates that the reduction of DTBN is affected by photosystem II of the electron transport system of spinach chloroplasts. The reduced form of DTBN, the hydroxylamine, undergoes a photo-oxidation with spinach chloroplasts. Possible explanations of this apparent inconsistency are presented. A product which could be ascribed to a chemical coupling reaction between the nitroxide and the radical species giving rise to the photo-induced EPR signals in spinach chloroplasts was not detected, even using radioactive tracer methods.

The influence upon axial stability in an electron ring of the diffraction radiation reaction force, generated by a ring moving in an acceleration column, is calculated theoretically. A stability criterion is obtained, and numerical examples show that the criterion is not an important constraint upon the choice of parameters or the operation of an electron ring accelerator.

Static quadrupole moments of the first excited states of {sup 28}Si, {sup 32}S, and {sup 40}Ar have been measured using the reorientation effect in projectile Coulomb excitation. The results obtained are Q({sup 28}Si,2{sup +}) = +0.11 {+-} 0.05 b, Q({sup 32}S,2{sup +}) = -0.20 {+-} 0.06 b, and Q({sup 40}Ar, 2{sup +}) = +0.01 {+-} 0.04 b.

Early in 1968 a research group was set up at the Lawrence Radiation Laboratory to investigate the exciting new concept of accelerating ions by means of relativistic electron rings, which had been introduced and developed by Veksler, Sarantsev, and other workers at Dubna. The initial work of our group was reported at the first USSR National Conference on Particle Accelerators in 1968. In this report the author review the subsequent progress and the present program.

The authors have measured the asymmetry in the cross section for the reaction {gamma}p {yields} {pi}{sup +}n between the two stages of polarization of the initial proton normal to the plane of scattering. The initial laboratory photon energies, k, were 5 GeV and 16 GeV, and the regions of momentum transfer, t, covered were 0.14 {le} {radical}-t {le} 1.01 GeV/c and 0.14 {le} {radical}-t {le} 0.78 GeV/c respectively. A butanol polarized target was used with the SLAC 20 GeV/c magnetic spectrometer. The data show a sizeable asymmetry at both 5 GeV and 16 GeV. The 16 GeV data peak at {radical}-t {approx} 0.30 GeV/c with an asymmetry of about -0.70, and the 5 GeV data pak at {radical}-t {approx} 0.80 GeV/c with an asymmetry of about -0.70. The direction of our normal to the scattering plane is along (photon in) x (pion out).

An equilibrium theory of the length of intense electron bunches circulating in a storage ring is presented. The consequence of electrical interaction with various resonant structures is expressed in terms of quadratures over the impedance of the structures, and impedance functions for a variety of elements are evaluated. It is shown that elements having resonances at high frequency can, above transition, cause bunches to increase in length with increasing current. The parametric dependence of the bunch lengthening is found to be in good agreement with observations, and numerical estimates, which are in substantial agreement with experiment, are presented.

In experiments related to the development of the electron-ring accelerator, electrons were injected into a pulsed magnetic field to form rings that were then compressed radially to a small size. The injected beam had a current of about 150 A at an energy of 3.3 MeV with an energy spread of {+-} 0.1% and a pulse length duration of 20 nsec. At low intensity, an increase in the minor radius of the ring and a large loss of electrons was observed to occur during the compression cycle. At high intensity, cooperative phenomena that caused a large increase in the energy spread accompanied by particle loss were observed. Theoretical interpretation of these observations suggests that the primary source of electron loss and enlargement of the axial dimension was the crossing of single-particle resonances during compression in the presence of large magnetic field nonlinearities and perturbations. The cooperative phenomena are interpreted as resulting from a negative mass instability. Despite the large minor radius and small number of electrons, experiments on extracting the ring were performed; under acceleration the ring failed to retain its integrity because of inadequate self-focusing.

A calculation is given of the radiated energy loss from a charged rod which moves at constant speed past an infinite set of parallel semi-infinite conducting plates of infinitesimal thickness, with the rod taken parallel to and at a fixed distance from the plate edges. The problem is analyzed using the Wiener-Hopf technique, and the resulting formulas are evaluated analytically in the limits of high rod speed and low rod speed, and compared with numerical evaluation over the full range of speeds.

We discuss the possibility of using synchrotron radiation to form electron rings having a very high electric field to hold the ions inside the ring. The formulas describing bow the energy and the dimension of the ring change under the effect of synchrotron radiation are derived, and a numerical example is given.

The carcinogenic activity of the benzo[a]pyrene 1, the 7,12-dimethylbenz[a]anthracene 2 and the 3-methylcholanthrene 3 is suggested to be determine by the electrophilic attack of the active oxygen, induced by the hydroxylating enzyme systems, on the most reactive substituting carbon atom(s). The cationic intermediate(s) with the charge mainly localized on a complementary, interrelated position(s) of the hydroxyl substituted position(s) reacts further with the cellular nucleophiles. The electrophilic nature of the ultimate chemical carcinogens constitutes the common distinctive feature that correlates their different structures and allows us to understand their carcinogenicity. The formation of a covalent bond with the nucleophiles of the biological macromolecules, nucleic acids and proteins, appears to be the essential requirement in the primary process of carcinogenesis.

The production of high energy (multi-GeV) proton beams by an electron ring accelerator is considered. Both the final energy and intensity of the proton beam depend on the choice of parameters for the electron ring. Possible sets of parameters, consistent with all the known requirements of ring stability, and which optimize the energy and (or) the intensity of the proton beam, are presented.

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The possibility of using the collective field of a large number of electrons to effect the acceleration of protons to high energies in a compact accelerator--or to permit acceleration of heavier ions in a manner not critically dependent on the charge-to-mass ratio of these ions--has been noted in an earlier Comment. A most attractive conceptual form for such an accelerator is the electron ring accelerator (ERA) and in the present Comment they direct attention to the basic phenomena--insofar as they know them--that govern the design and operation of an ERA. Briefly, the ERA concept visualizes the use of a compact ring of relativistic electrons that circulate in a plane perpendicular to an external magnetic field. The ring is partially neutralized by ions held in the potential well of the electrons. The electric field of these ions and the magnetic attractive forces between the circulating electrons then together act to overcome the electrostatic repulsion of the electrons and make possible the achievement of a configuration that is self-stable in the absence of external focusing fields. Acceleration of the ring with its accompanying ions, in a direction perpendicular to the plane of the ring, can be achieved (at the expense of the …

An article fro Aerospace Historian on the origins and life of Women Airforce Service Pilots in World War II, with an introduction from aviatrix and WASP flight instructor, Jacqueline Cochran.

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A Sarcina strain (Coccus P) produces two proteolytic enzymes. One is found only extracellularly, is far more prevalent, and is actively excreted during exponential growth. It is the enzyme responsible for the known strong proteolytic activity of the cultures of this strain. A second protease is, however, produced which remains associated with the intact cells but is released by the protoplasts. The two enzymes appear unrelated in their derivation. Calcium ions play an essential role in preventing autodigestion of the excreted enzyme. Bacterial proteins are found outside the cell boundary as a consequence either of passive processes such as leakage or lysis or of active excretion. Under conditions in which leakage and lysis do not occur, as during exponential growth, the cell boundary is a barrier causing a complete separation of the bulk of the intracellular proteins from the one or very few extracellular proteins, with no trace of either type being detectable on the wrong side of the boundary. Since in bacteria there is no evidence of protein being produced other than internally, the separation into intraand extracellular proteins should occur after peptide chain formation. The question arises as to whether the structure of the cell boundary or that …

It has been known that the extracellular proteinase of Coccus P is found only in cultures grown in the presence of Ca{sup 2+}. It is now shown that this cation is required neither for synthesis, excretion, or activation of a zymogen nor as a prosthetic factor necessary for enzymatic activity. The only function of Ca{sup 2+} is to stabilize the active structure of the enzyme molecule, presumably by substituting for absence of S-S bridges. In the absence of Ca{sup 2+} , the excreted proteinase undergoes rapid autodigestion and, instead of the active protein, its hydrolytic products are accumulated in the culture fluid. In minimal medium and under conditions of enzyme stability [presence of Ca{sup 2+} and Ficoll (Pharmacia)], Coccus P accumulates the proteinase at a gradually reduced speed although the rate of cultural growth remains constant. It is shown that this decline in rate of accumulation is caused by the excreted proteinase itself, possibly acting on its own precursor emerging from the cell in a form susceptible to proteolytic attack and not amenable to Ca{sup 2+} protection. A proteinase precursor is actually demonstrable in a calciumless culture at the onset of the enzyme accumulation which follows Ca{sup 2+} addition. It …

Article discussing research on vegetative cells and cysts for Azotobacter vinelandii 12837 prepared for electron microscopy by several methods assumed to preserve structural details destroyed by techniques previously reported in literature.

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