bluuebunny/crossref_metadata_2025 huggingface dataset:
Autoionization and neutral dissociation of superexcited HI studied by two-dimensional photoelectron spectroscopy
Authors: Hikosaka Yasumasa , Mitsuke Koichiro
Published: June 2004

Two-dimensional photoelectron spectroscopy of hydrogen iodide (HI) has been performed in the photon energy region of 11.10–14.85 eV, in order to investigate dynamical properties on autoionization and neutral dissociation of Rydberg states HI*(RA) converging to HI+(Ã 2Σ1/2+). A two-dimensional photoelectron spectrum exhibits strong vibrational excitation of HI+(X̃ 2Π) over a photon energy region from ∼12 to 13.7 eV, which is attributable to the autoionizing feature of the 5dπ HI*(RA) state. A noticeable set of stripes in the photon energy region of 13.5–14.5 eV is assigned as resulting from autoionization of the atomic Rydberg states of I* converging to I+ (3P0 or P13). The formation of I* is understood in terms of predissociation of multiple HI*(RA) states by way of the repulsive Rydberg potential curves converging to HI+(4Π1/2).
Quantum dynamics of vibrationally activated OH–CO reactant complexes
Authors: He Yong , Goldfield Evelyn M. , Gray Stephen K.
Published: June 2004

A six-dimensional wave packet study of the unimolecular decay of vibrationally activated OH–CO reactant channel complexes is presented. The ab initio based Lakin–Troya–Schatz–Harding potential energy functions for the A′ and A″ states are employed. Good agreement with the experimental product distributions and lifetimes of Pond and Lester is found. We are able to confirm that complexes with two vibrational quanta of excitation in OH, vOH=2, and no vibrational excitation in CO, vCO=0, decay through two pathways. One pathway leads to products (vOH=1, vCO=0) with relatively high OH rotational energy and the other leads to products (vOH=1, vCO=1) with relatively low OH rotational energy. We also find that the lifetime of the A″ state is less than the A′ state and that there is a propensity for A″ products.
The permanent electric dipole moments of calcium monohydride, CaH
Authors: Steimle T. C. , Chen Jinhai , Gengler Jamie
Published: June 2004

Numerous branch features in the (0,0) A 2Π-X 2Σ+ band system of calcium monohydride CaH have been studied by optical Stark spectroscopy. The Stark shifts, Stark splittings, and appearance of electric-field-induced transitions in the high resolution laser-induced fluorescence spectra are analyzed to produce values for the magnitude of the permanent electric dipole moments |μ| of 2.94(16) D and 2.372(12) D for the X 2Σ+(v=0) and A 2Π(v=0) states, respectively. A comparison with values predicted from a semiempirical electrostatic model and previous ab initio calculations for |μ| (X 2Σ+) is presented. The change in |μ| upon excitation from the X 2Σ+ state to the A 2Π state is rationalized using a simple molecular orbital description.
Parallel iterative reaction path optimization in ab initio quantum mechanical/molecular mechanical modeling of enzyme reactions
Authors: Liu Haiyan , Lu Zhenyu , Cisneros G. Andrés , Yang Weitao
Published: June 2004

The determination of reaction paths for enzyme systems remains a great challenge for current computational methods. In this paper we present an efficient method for the determination of minimum energy reaction paths with the ab initio quantum mechanical/molecular mechanical approach. Our method is based on an adaptation of the path optimization procedure by Ayala and Schlegel for small molecules in gas phase, the iterative quantum mechanical/molecular mechanical (QM/MM) optimization method developed earlier in our laboratory and the introduction of a new metric defining the distance between different structures in the configuration space. In this method we represent the reaction path by a discrete set of structures. For each structure we partition the atoms into a core set that usually includes the QM subsystem and an environment set that usually includes the MM subsystem. These two sets are optimized iteratively: the core set is optimized to approximate the reaction path while the environment set is optimized to the corresponding energy minimum. In the optimization of the core set of atoms for the reaction path, we introduce a new metric to define the distances between the points on the reaction path, which excludes the soft degrees of freedom from the environment set and includes extra weights on coordinates describing chemical changes. Because the reaction path is represented by discrete structures and the optimization for each can be performed individually with very limited coupling, our method can be executed in a natural and efficient parallelization, with each processor handling one of the structures. We demonstrate the applicability and efficiency of our method by testing it on two systems previously studied by our group, triosephosphate isomerase and 4-oxalocrotonate tautomerase. In both cases the minimum energy paths for both enzymes agree with the previously reported paths.
Structural and magnetic model of self-assembled FePt nanoparticle arrays
Authors: Thomson T. , Toney M. F. , Raoux S. , Lee S. L. , Sun S. , Murray C. B. , Terris B. D.
Published: June 2004

Chemically ordered, self-assembled FePt nanoparticle arrays with high magnetic anisotropy are considered as a candidate medium for data storage beyond 1 Tbit/in2. We report comprehensive structural and magnetic studies on thin (three-layer) assemblies of polyethylenimine (PEI) and 4 nm Fe58Pt42 nanoparticles using x-ray diffraction, small angle neutron scattering, and magnetometry. We show that prior to annealing FePt nanoparticles in the PEI-FePt assembly consist of a metallic magnetic core surrounded by a weakly magnetic or nonmagnetic shell. High temperature annealing creates the desired L10 chemical ordering and results in high coercivity FePt nanoparticles. However, we find that the high temperatures necessary to establish full chemical ordering leads to particle sintering and agglomeration. Understanding the magnetic and physical properties of these assemblies allows future research directions to be clarified for nanoparticle arrays as data storage media.
Generation and transport of a low energy intense ion beam
Authors: Bystritskii Vit. , Garate E. , Rostoker N. , Song Y. , VanDrie A. , Anderson M. , Qerushi A. , Dettrick S. , Binderbauer M. , Walters J. K. , Matvienko V. , Petrov A. , Shlapakovsky A. , Polkovnikova N. , Isakov I.
Published: June 2004

The paper describes experiments on the generation and transport of a low energy (70–120 keV), high intensity (10–30 A/cm2) microsecond duration H+ ion beam (IB) in vacuum and plasma. The IB was generated in a magnetically insulated diode (MID) with an applied radial B field and an active hydrogen-puff ion source. The annular IB, with an initial density of ji∼10–20 A/cm2 at the anode surface, was ballistically focused to a current density in the focal plane of 50–80 A/cm2. The postcathode collimation and transport of the converging IB were provided by the combination of a “concave” toroidal magnetic lens followed by a straight transport solenoid section. With optimized MID parameters and magnetic fields in the lens/solenoid system, the overall efficiency of IB transport at the exit of the solenoid 1 m from the anode was ∼ 50% with an IB current density of 20 A/cm2. Two-dimensional computer simulations of post-MID IB transport supported the optimization of system parameters.
Viscosities of liquid CdTe near melting point from ab initio molecular-dynamics calculations
Authors: Ko Eunjung , Alemany M. M. G. , Chelikowsky James R.
Published: June 2004

Recent experimental results for the viscosity of liquid CdTe exhibit disparate behavior as a function of temperature. While some measurements show the expected Arrhenius-type behavior, other measurements show an anomalous temperature dependence indicating an increase in viscosity with increasing temperature. We present ab initio molecular-dynamics simulations of liquid cadmium telluride near its melting point and use the Stokes–Einstein relation to extract values of the viscosity constant. We find no anomalous behavior; the viscosity decreases monotonically with temperature and is consistent with an Arrhenius like behavior. Although calculated values are slightly smaller than those measured, the predicted activation energy agrees well with experiment.
Phase changes in selected Lennard-Jones X13−nYn clusters
Authors: Sabo Dubravko , Predescu Cristian , Doll J. D. , Freeman David L.
Published: June 2004

Detailed studies of the thermodynamic properties of selected binary Lennard-Jones clusters of the type X13−nYn (where n=1, 2, 3) are presented. The total energy, heat capacity, and first derivative of the heat capacity as a function of temperature are calculated by using the classical and path integral Monte Carlo methods combined with the parallel tempering technique. A modification in the phase change phenomena from the presence of impurity atoms and quantum effects is investigated.
Influence of AlN overgrowth on structural properties of GaN quantum wells and quantum dots grown by plasma-assisted molecular beam epitaxy
Authors: Gogneau N. , Jalabert D. , Monroy E. , Sarigiannidou E. , Rouvière J. L. , Shibata T. , Tanaka M. , Gerard J. M. , Daudin B.
Published: June 2004

The effects of AlN overgrowth on the structural properties of GaN nanostructures (quantum wells and quantum dots) grown by plasma-assisted molecular beam epitaxy have been investigated using Rutherford backscattering spectroscopy, transmission electron microscopy, and reflection high-energy electron diffraction. The capping process induces a remarkable change in the dimensions of the nanostructures. The overgrowth process implies a thinning of the GaN quantum well and an isotropic reduction of the GaN island size. We demonstrate that this thickness/size reduction affects only the top GaN/AlN interface. The phenomenon is attributed to an exchange mechanism between Al atoms from the cap layer and Ga atoms in the nanostructures. We also demonstrate that this exchange is thermally activated and depends on the strain state of the nanostructures.
Influence of design and operation parameters on Hall thruster performances
Authors: Ahedo E. , Escobar D.
Published: June 2004

A stationary, macroscopic model [E. Ahedo, J. Gallardo, and M. Martı́nez-Sánchez, Phys. Plasmas 10, 3397 (2003)] is used to carry out parametric investigations on the effects of (i) the discharge voltage, (ii) the gas flow rate, (iii) the axial gradient of the magnetic field, and (iv) the chamber length on the Hall thruster performances and the axial structure of the plasma discharge. The high-thrust and high-specific-impulse modes for dual-mode thrusters are compared too. The results of the simulations agree well with the main tendencies observed in different experiments. The interaction among the several physical phenomena is discussed and useful scaling laws are proposed. Special attention is paid to understand (i) the adjustment of the magnetic field strength with the discharge voltage for optimum operation, (ii) the effect of the magnetic field shape, (iii) the dimensions of the different regions of the discharge, and (iv) the parameter trends needed to increment the propulsive and ionization efficiencies (the product of which determines the thrust efficiency).
Stark effect in semiconductor quantum dots
Authors: Pokutnyi S. I. , Jacak L. , Misiewicz J. , Salejda W. , Zegrya G. G.
Published: June 2004

A theory of the Stark effect in semiconductor quantum dots has been developed for the case of dominating polarization interaction of an electron and a hole with the nanocrystal surface. A shift of electron and hole quantum well levels in a nanocrystal in the interband absorption range in a uniform external electric field is determined by the quantum-confinement quadratic Stark effect. An electro-optical method is proposed, making it possible to estimate the characteristic quantum dot radius at which three-dimensional excitons can exist.
The influence of polytypic structures on the M011→M101 solid–solid phase transition of n-C36H74: An application of the oblique infrared transmission method
Authors: Kubota Hideki , Kaneko Fumitoshi , Kawaguchi Tatsuya , Kawasaki Masatsugu
Published: June 2004

The molecular displacements on the M011→M101 phase transition of n-hexatriacontane (n-C36H74) have been investigated with an IR microscope designed for the oblique infrared transmission method. It has been clarified that two polytypic structures of the M011 modification, single-layered structure (Mon) and double-layered one (Orth II), both transform to the M101 modification of single-layered structure with their respective mechanisms. On the M011(Mon)→M101 transition, the inclination direction of molecular axis is changed by 90° through an intermediate state in which the molecular chain is set perpendicular to the basal plane of the single crystal. On the other hand, a polymorphic-polytypic composite structural change on the M011(Orth II)→M101 transition is accomplished through two kinds of molecular displacements occurring alternately along the stacking direction of molecular layers.
Correlation of transport and optical properties of Si-doped Al0.23G0.77N
Authors: James G. R. , Leitch A. W. R. , Omnès F. , Wagener M. C. , Leroux M.
Published: June 2004

The properties of Si-doped Al0.23Ga0.77N grown by metalorganic vapor-phase epitaxy have been investigated by photoluminescence and Hall effect measurements. Nonintentionally doped samples were found to be insulating, while the room temperature carrier concentration of the doped layers did not vary linearly with the silane flow. The Si donor activation energy decreases with the doping level and the results correlate very well with those of Si-doped GaN. The temperature dependence of the photoluminescence spectra of the samples, in particular, their quenching with increasing temperature, can be explained by considering characteristic energies deduced from the Hall effect measurements. Our study shows that Al0.23Ga0.77N is a well-behaved semiconductor alloy, in which Si is a standard hydrogeniclike donor.
Nonadiabatic alignment of asymmetric top molecules: Rotational revivals
Authors: Poulsen Mikael D. , Péronne Emmanuel , Stapelfeldt Henrik , Bisgaard Christer Z. , Viftrup Simon S. , Hamilton Edward , Seideman Tamar
Published: June 2004

The rotational revival structure of asymmetric top molecules, following irradiation by an intense picosecond laser pulse, is explored theoretically and experimentally. Numerically we solve nonperturbatively for the rotational dynamics of a general asymmetric top subject to a linearly polarized intense pulse, and analyze the dependence of the dynamical alignment on the field and system parameters. Experimentally we use time-resolved photofragment imaging to measure the alignment of two molecules with different asymmetry, iodobenzene, and iodopentafluorobenzene. Our numerical results explain the experimental observations and generalize them to other molecules. The rotational revival structure of asymmetric tops differs qualitatively from the intensively studied linear top case. Potentially it provides valuable structural information about molecules.
Subcritical wave instability in reaction-diffusion systems
Authors: Vanag Vladimir K. , Epstein Irving R.
Published: June 2004

We report an example of subcritical wave instability in a model of a reaction-diffusion system and discuss the potential implications for localized patterns found in experiments on the Belousov-Zhabotinsky reaction in a microemulsion.
Spectroscopic study of Nd-doped amorphous SiN films
Authors: Ribeiro C. T. M. , Siu Li M. , Zanatta A. R.
Published: June 2004

Neodymium-doped amorphous silicon-nitrogen (a-SiN) thin films have been prepared by cosputtering a (Si+Nd) target in a nitrogen atmosphere. After deposition the films were submitted to cumulative thermal annealing treatments and investigated in detail by Raman scattering spectroscopy, optical transmission, x-ray photoelectron spectroscopy (XPS), and photoluminescence techniques. Additional information was also obtained from ion beam analyses such as Rutherford backscattering spectrometry and nuclear reaction analysis. As a result of the deposition method and conditions, the films are amorphous and contain ≈0.8 at % of neodymium. Actually, Raman scattering measurements indicate that the present films remain amorphous even after thermal anneal at 1000 °C. The electronic states at the top of the valence band of the Nd-doped a-SiN films were investigated by XPS, which indicates that most of the neodymium present in the a-SiN host stays under the trivalent (Nd3+) form. As a consequence, relatively strong and well-defined photoluminescence signal could be observed in the infrared energy range corresponding to internal 4f transitions due to the Nd3+ ions. The achievement of this optical emission is highly susceptible both to the thermal annealing treatment and to the energy of photon excitation. Whereas the former determines the atomic environment of the Nd3+ ions, the latter indicates the most efficient route to their optical excitation. Based on various experimental techniques, and as a result of a systematic investigation, the present manuscript contains an extended and comprehensive discussion on the principal spectroscopic characteristics of the Nd-doped amorphous SiN system.
Phenomenological model of anisotropic volume hologram formation in liquid-crystal-photopolymer mixtures
Authors: Sutherland R. L. , Tondiglia V. P. , Natarajan L. V. , Bunning T. J.
Published: June 2004

The real time formation of anisotropic volume holographic reflection gratings in a liquid-crystal/photopolymer mixture is studied. We develop a phenomenological model of grating formation that incorporates the photophysics and photochemistry of the initiator dye, reaction-diffusion kinetics of the monomer-polymer system, phase separation of the liquid crystal, nematic order evolution of liquid-crystal droplets, and volume shrinkage of the polymer. We then test this model by experimentally monitoring the diffraction efficiency for s and p polarization, Bragg wavelength, and laser scattering in real time as the grating is formed. The model yields good agreement with experimental data for different recording intensities and exposure times. We discuss the physics of the system as it evolves in time and explain the major features of anisotropic grating formation in acrylate-based holographic polymer-dispersed liquid crystals.
Magnetic properties of stoichiometric and nonstoichiometric ultrathin Fe3O4(111) films on Al2O3(0001)
Authors: Schedin F. , Hill E. W. , van der Laan G. , Thornton G.
Published: June 2004

A detailed characterization of magnetic oxide films is essential to enable their use in magnetoresistive devices since their properties depend critically on stoichiometry and structural order. Here, the composition and magnetic properties of ultrathin iron oxide films grown epitaxially on Al2O3(0001) have been characterized using x-ray magnetic circular dichroism XMCD and magnetoresistance (MR) measurements. The XMCD data show by comparison with theoretical calculations that we have successfully found growth conditions for well ordered epitaxial films with Fe3O4 stoichiometry. Nonstoichiometric films exhibit, in addition to a relative reduction in Fe2+ ions, a net transfer of Fe3+ from tetrahedral to octahedral sites. The in-plane MR for both these films is found to be 1% at room temperature in a field of 1 T even though the electrical conductivity differs by a factor of 5.
Raman spectroscopy of in situ annealed InAs/GaAs quantum dots
Authors: De Luna M. J. M. , Somintac A. , Estacio E. , Salvador A.
Published: June 2004

Nonresonant Raman scattering measurements were performed on a three-layered sample of in situ annealed InAs/GaAs self-assembled quantum dots. The thermal annealing step was done during the growth of each GaAs spacer layer, where the substrate temperature was raised from 530 °C to 580 °C as measured by a pyrometer. Three Raman signals are clearly seen at 264 cm−1, 268 cm−1, and 271.5 cm−1 which can be attributed to the longitudinal optic (LO) phonons of the dots. These three different signals are attributed to different degrees of In/Ga alloying or intermixing in each dot layer as a consequence of the different thermal treatments that each layer was subjected to. The Raman signal of the wetting layer (WL) is remarkably weak and suggests erosion of the wetting layer. In contrast, Raman scattering measurements on an unannealed sample show two overlapping features at 259.5 cm−1 and 261.5 cm−1, which are attributed to the LO phonons of the dots. The WL signal is clearly observed at 251.5 cm−1. To support our Raman observations, the appearance of a strong higher-energy peak in photoluminescence measurements suggests that alloying did occur in the annealed sample.
Semiconductor to metal phase transition in the nucleation and growth of VO2 nanoparticles and thin films
Authors: Suh J. Y. , Lopez R. , Feldman L. C. , Haglund R. F.
Published: June 2004

The optical and morphological characteristics of vanadium dioxide nanoparticles and thin films during their nucleation and growth phases have been studied by correlating the temperature and sharpness of the transition with the processing parameters. Thermal annealing results in grain growth and improved crystallinity. Normally, larger crystallites show smaller hysteresis, as there is a greater probability of finding a nucleating defect in the larger volume. But at the same time, this improved crystal perfection, which accompanies the thermal annealing and grain growth, tends to a larger hysteresis, as there are fewer nucleating defects within the volume. We show that the width and shape of the hysteresis cycle are thus determined by the competing effects of crystallinity and grain size.
Influence of the buffer layers on magnetic properties of FePt (001) films sputter-deposited at reduced temperature
Authors: Seki T. , Shima T. , Takanashi K. , Takahashi Y. , Matsubara E. , Takahashi Y. K. , Hono K.
Published: June 2004

The magnetic properties of Fe38Pt62 and Fe52Pt48 films sputter deposited on MgO (001) substrates with and without a buffer layer at the substrate temperature Ts of 300 °C have been investigated. Pt, Au, and PtAu alloys with different compositions were used as the buffer layer to study the influence of the lattice mismatch between the FePt layer and the buffer layer. The L10 ordered structure with large perpendicular magnetic anisotropy has been obtained for the Fe38Pt62 films irrespective of the buffer layer. The degree of long-range order S and uniaxial magnetic anisotropy energy Ku increase with increasing the lattice mismatch, and S and Ku show maxima of 0.8±0.1 and 2.7×107 erg/cm3, respectively, for the film without a buffer layer. For Fe52Pt48 films, on the other hand, the L10 ordered structure with perpendicular magnetic anisotropy has been obtained only for the film with an Au buffer layer.
Ge composition dependence of properties of solar cells based on multicrystalline SiGe with microscopic compositional distribution
Authors: Pan Wugen , Fujiwara Kozo , Usami Noritaka , Ujihara Toru , Nakajima Kazuo , Shimokawa Ryuichi
Published: June 2004

We present device performance of solar cells based on multicrystalline SiGe (mc-SiGe) bulk crystal with microscopic compositional distribution grown by the casting method. The average Ge composition was systematically changed in the range between 0% and 10%. A small addition of Ge to multicrystalline Si (mc-Si) was found to be very effective to increase the short-circuit current density without affecting the open-circuit voltage. As a consequence, the overall efficiency of a solar cell based on mc-SiGe was improved compared with that based on mc-Si. This result demonstrates that mc-SiGe is a promising candidate to replace mc-Si since it could achieve higher conversion efficiency without drastic increase of the production cost.
Experimental and numerical investigation of turbulent flow induced pipe vibration in fully developed flow
Authors: Pittard Matthew T. , Evans Robert P. , Maynes R. Daniel , Blotter Jonathan D.
Published: June 2004

Flow-induced pipe vibration caused by fully developed pipe flow has been observed but not fully investigated when turbulent flow prevails. This article presents experimental results that indicate a strong correlation between the volume flow rate and a measure of the pipe vibration. In this work, the standard deviation of the frequency-averaged time-series signal, measured using an accelerometer attached to the pipe, is used as the measure of pipe vibration. A numerical, fluid-structure interaction (FSI) model used to investigate the relationship between pipe wall vibration and the physical characteristics of turbulent flow is also presented. This numerical FSI approach, unlike commercial FSI software packages, which are based on Reynolds averaged Navier-Stokes flow models, is based on large eddy simulation (LES) flow models that compute the instantaneous pressure fluctuations in turbulent flow. The results from the numerical LES models also indicate a strong correlation between pipe vibration and flow rate. In general, the numerical simulations show that the standard deviation of the pipe wall vibration is proportional to the pressure fluctuations at the wall induced by the flow turbulence. This research, indicates that the pressure fluctuations on the pipe wall have a near quadratic relationship with the flow rate. Furthermore, the experimental results and the numerical modeling show that there is a definite relationship between the acceleration of the pipe (pipe vibration) and the flow rate. These last two concepts open possible avenues for the development of a non-intrusive flow sensor.
Analytic, high-β solutions of the helical Grad–Shafranov equation
Authors: Smith D. R. , Reiman A. H.
Published: June 2004

Analytic, high-β [β∼O(1)], helical equilibrium solutions are presented for a class of helical axis configurations having large helical aspect ratio, with the helix assumed to be tightly wound. The solutions develop a narrow boundary layer of strongly compressed flux, similar to that previously found in high-β tokamak equilibrium solutions. The boundary layer is associated with a strong localized current which prevents the equilibrium from having zero net current.
Cross-Border Cooperation and Transformation of Regional Identities in the Ukrainian–Russian Borderlands: Towards a Euroregion “Slobozhanshchyna”? Part 2*
Authors: Zhurzhenko Tatiana
Published: June 2004

Let us now have a closer look at the Kharkiv-Belgorod (potential) cross-border region as a case study of Ukrainian-Russian cross-border cooperation. Not only is the case of Kharkiv-Belgorod special because of the historical and cultural specificity of the region, which provides additional symbolic resources for its “reinvention” as a borderland (this will be discussed in the last section of the paper); it also represents an interesting combination of (remaining) cultural closeness and (growing) social and economic differences between the two bordering territories; significantly, these two administrative units became the initiators of the cross-border cooperation between Ukraine and Russia and see themselves as pioneers whose experience can be used for the other parts of the border.
Carcinogenic Susceptibility to N-bis(2-hydroxypropyl)nitrosamine (DHPN) in rasH2 Mice
Authors: Okamura Miwa , Moto Mitsuyoshi , Kashida Yoko , Machida Noboru , Mitsumori Kunitoshi
Published: June 2004

To evaluate the susceptibility of rasH2 mice to N-bis(2-hydroxypropyl)nitrosamine (DHPN), a potent carcinogen targeting the lung, liver, thyroid, and kidney, male, 6-week old, rasH2 mice and wild-type Iittermates (non-Tg mice) were given DHPN in drinking water at 0, 20 or 200 ppm, and 0 or 200 ppm, respectively, for 26 weeks. The experiment using rasH2 mice given 200 ppm DHPN and non-Tg mice given 200 and 0 ppm DHPN was completed at 20 weeks, since mortality in these groups was remarkably increased due to hemangiosarcomas of the liver. Histologically, tumors developed in the lung and liver in both rasH2 and non-Tg mice treated with DHPN. In addition, proliferative lesions were observed in the forestomach, urethra, and excretory duct of salivary glands in rasH2 mice given 200 ppm DHPN. RT-PCR analysis showed no marked difference in expression of mRNAs for the transgene and the endogenous mouse ras gene between the whole lung tissue containing a neoplasm and normal lung tissue. Our results suggest that rasH2 mice are highly susceptible to DHPN, the target organs including the forestomach, salivary gland and urethra, which have not been found to develop tumors in previous long-term carcinogenicity studies of DHPN in rats and mice.
THE INTERACTION OF DONOR AND HOST LYMPHOID CELLS IN THE PATHOGENESIS OF RENAL CORTICAL DESTRUCTION INDUCED BY A LOCAL GRAFT VERSUS HOST REACTION
Authors: Elkins William L.
Published: June 2004

The graft versus host reaction (GVHR), which results from the injection of parental strain spleen cells beneath the kidney capsule of F1 hybrid rats, is transferable during its developmental phase into F1 hybrid hosts isogeneic with the primary host, but not into secondary hosts of the parental (donor) strain. Furthermore, the GVHR propagates but rarely in secondary hybrid hosts which are allogeneic with respect to the primary hosts, but which are also genetically tolerant of donor-type cells. These findings indicate that the donor cells not only initiate the GVHR but also maintain it by virtue of immunologically specific activity.

Whole-body irradiation of (LBf)F1 and (LBN)F1 hosts 24 hours prior to the injection of parental (L) spleen cells results in inhibition of the subsequent GVHR to a degree commensurate with the radiation damage sustained by the lymphoid system of the host. Furthermore, propagation of transferred GVHRs did not occur if susceptible secondary hybrid hosts had been previously irradiated. These findings indicate that radiosensitive host cells play a continuing and essential role in the pathogenesis of the invasive-destructive lesion. It is concluded that the development of this lesion depends upon the continuous interaction of the specifically reactive donor-type cells with an immunologically non-specific population of host mononuclears.
IN VITRO STUDIES ON RADIATION LYMPHOID RECOVERY OF MOUSE SPLEEN
Authors: Globerson Amiela
Published: June 2004

In vitro studies, utilizing an organ culture method were reported on mutual interactions between irradiated spleen, normal bone marrow, and thymus. It has been shown; (a) that singly isolated spleen explants were incapable of lymphoid regeneration, (b) thymus had no stimulatory effect on spleen regeneration, (c) bone marrow interacted synergistically with spleen leading to appearance of lymphoid cells which were not detected in singly isolated bone marrow or spleen, and (d) no stimulation of lymphopoiesis in bone marrow was conferred by thymus in the absence of spleen.

The results are discussed in terms of possible mechanisms involved in lymphoid radiation recovery in vivo.
IMMUNOLOGIC COMPETENCE OF THORACIC DUCT CELLS
Authors: Coe John E. , Feldman Joseph D. , Lee Sun
Published: June 2004

Delayed hypersensitivity was produced in donor Lewis rats by sensitization with soluble protein antigens emulsified in complete Freund's adjuvant. Cells of their thoracic duct lymph were collected for varying periods of time and transferred intravenously to isogenic Lewis recipients. With this model the following conclusions were reached:

1. Delayed hypersensitivity was transferred by thoracic duct cells.

2. The longer the drainage of the thoracic duct, the fewer cells were needed to achieve a successful transfer. With continuing drainage the proportion of small lymphocytes decreased and large cells increased. There was, therefore, a better correlation between successful transfer of delayed hypersensitivity and the number of large cells transfused than between positive skin reactions and transfer of small lymphocytes.

3. Prolonged fistula of the thoracic duct did not diminish the skin reaction of sensitized donors to specific antigen.

4. Delayed hypersensitivity was elicited in recipients 3 wk after transfer of sensitized cells. There was evidence that delayed hypersensitivity was enhanced in recipients, possibly because of prior skin testing.

5. Total body X-irradiation abolished the lesions of passively transferred delayed hypersensitivity. Recovery of positive skin tests was observed 19 to 20 days later.

6. The lesions of delayed hypersensitivity were probably mediated by cells. There was no evidence that a circulating high affinity antibody played a role in this type of immunologic reaction.
AN INHERITED X-LINKED SERUM SYSTEM IN MAN
Authors: Berg Kåre , Bearn Alexander G.
Published: June 2004

The detection of an inherited X-linked serum system in man, disclosed by a heteroantisenim made specific by absorption, is described. These studies suggest that the antigen, demonstrated by the specific antiserum, resides in the α2-macroglobulin fraction of serum. The system has been named the Xm system, where X refers to the localization of the gene on the X chromosome, and the m indicates that the antigen is part of the α2-macroglobulin fraction.

The distribution of phenotypes in unrelated individuals from 4 populations, as well as studies performed in families are consistent with an X-linked dominant mode of inheritance. One Xm(a-) daughter was found in a family where the father was Xm(a+). This finding is discussed with particular reference to the possible influence of sex and age on the development of the phenotype.

This common X-linked marker is likely to prove useful in mapping the human X chromosome.
ELECTRON MICROSCOPIC STUDIES OF HUMAN GLOMERULONEPHRITIS WITH FERRITIN-CONJUGATED ANTIBODY
Authors: Andres Giuseppe A. , Accinni Lidia , Hsu Konrad C. , Zabriskie John B. , Seegal Beatrice C.
Published: June 2004

1. Kidney biopsies from 4 cases of severe acute glomerulonephritis were obtained 11 to 25 days after the onset of clinical manifestations of the disease. These tissues were treated with ferritin-conjugated antibodies to 7S γ-globulin, ß1C, and Type 12 streptococcal products. Adjacent pieces of the biopsied material were treated with control ferritin-labeled antisera or with ferritin alone. As further controls, normal renal tissue and renal tissue from patients with other kidney diseases were treated with the same antisera.

The 3 antisera to 7S γ-globulin, ß1C and Type 12 streptococcus were specifically bound in electron-opaque foreign material in the following renal areas: (a) the lumen of glomerular capillaries; (b) medullary arteriolar walls (2 cases); (c) pinocytic vacuoles and absorption droplets of endothelial or mesangial cells; (d) canals between proliferating mesangial or endothelial cells which connect the capillary lumen with the deep mesangial region or with the endothelial side of the basement membrane; (e) basement membrane proper; (f) subendothelial and certain subepithelial deposits; and (g) Bowman's space.

2. None of the 3 ferritin-conjugated antisera listed above were bound to the nuclei of glomerular cells or to portions of the cytoplasm other than those specified.

3. Ferritin-conjugated antisera to pneumococcus Type II and vaccinia virus and ferritin alone were not bound to any structures in the glomerular tissue.

4. None of the ferritin-conjugated antisera bound to normal renal tissue or to kidney tissue from other renal disease.

5. The data obtained are compatible with the following working hypothesis: Antigen-antibody aggregates of Type 12 streptococcal products, γ-globulin, and complement are present in the circulating blood of patients with severe acute glomerulonephritis. Large amounts of the complexes are caught in the filtering system of the glomeruli. The inflammatory reactions seen in the glomerular structures result from the presence of the immune complexes and of the polymorphonuclear leukocytes which conjointly may be responsible for the disease.
STUDIES ON THE PATHOGENESIS OF FEVER
Authors: Rafter Gale W. , Cheuk S. Fai , Krause Donald W. , Wood W. Barry
Published: June 2004

Leukocytic pyrogen previously reported to contain an essential protein moiety, appears to be a lipid-protein complex having a molecular weight in the range of 10,000 to 20,000. Evidence that it contains essential lipid includes its inactivation by Cu++, its lability in alkaline solutions (pH 8.5 and above), and its loss of pyrogenicity when extracted with acid-isooctane. Its solubility in 66% methanol, and the enhancing action of ethanol in freeing it from sonicated cells, suggest the presence of exposed lipid groups at its surface. Once the complex is separated from other proteins, its biological activity is readily destroyed. Although the lipid component is presumed to contain unesterified fatty acid(s), its precise composition is unknown.

The finding of lipid in the active complex is in keeping with the hypothesis that the pyrogen is derived from leukocytic membranes.
AUTORADIOGRAPHIC ANALYSIS OF LYMPHOPOIESIS AND LYMPHOCYTE MIGRATION IN MICE BEARING MULTIPLE THYMUS GRAFTS
Authors: Matsuyama M. , Wiadrowski Margaret N. , Metcalf D.
Published: June 2004

Lymphopoiesis was studied in 3-month-old normal C57Bl mice and in 3-month-old C57Bl mice carrying from 12 to 48 C57Bl thymus grafts using tritiated thymidine labeling.

Thymus graft lymphopoiesis was found to be identical with that of normal thymus tissue and the presence of thymus grafts was found to have no influence on host thymus lymphopoiesis.

No evidence was found that the massive amounts of thymus graft tissue in the mice affected any parameter of host lymph node lymphopoiesis nor was any evidence detected for the migration of thymic lymphocytes from these massive deposits of thymus graft tissue either to host lymph nodes and blood or to other organs in the host animal.

It is concluded that the majority of small lymphocytes produced in the thymus and thymus graft tissue do not migrate from these tissues but die locally at the end of their intrathymic life span of 3 to 4 days.
AN ANTIVIRAL SUBSTANCE FROM PENICILLIUM FUNICULOSUM
Authors: Rytel Michael W. , Shope Richard E. , Kilbourne Edwin D.
Published: June 2004

Helenine, a substance obtained from broth cultures of Penicillium funiculosum and known to exert a protective effect in vivo in experimental animals against several unrelated viruses, has been shown to elicit the formation in cell cultures and in intact mice of an inhibitor of viral plaque formation.

Because the biological and chemical characteristics of the viral inhibitor induced by helenine are similar to those of interferon, it is suggested that the antiviral effect of helenine may be mediated through the formation of interferon.
SELECTIVE SUPPRESSION OF DELAYED HYPERSENSITIVITY BY THE INDUCTION OF IMMUNOLOGIC TOLERANCE
Authors: Borel Yves , Fauconnet Marthe , Miescher Peter A.
Published: June 2004

Administration of DNP-BGG to newborn guinea pigs resulted, in more than half of the animals, in the specific suppression of delayed hypersensitivity to DNP-BGG and BGG, as shown after immunization with DNP-BGG in complete Freund's adjuvant.

In contrast, all animals formed antibodies to DNP-BGG, whether or not delayed hypersensitivity to this antigen was present. No difference in antibody titers was found between pretreated and control animals. All animals had antibodies reacting specifically to the hapten DNP, and most of them to the carrier protein BGG, whether or not delayed hypersensitivity to the carrier protein was present. Furthermore, some animals with and without positive 24 hr skin test to DNP-BGG had antibodies with a combined hapten-carrier protein specificity to this antigen, i.e., a specificity which is similar to that of delayed hypersensitivity. Thus, delayed hypersensitivity and antibody formation to similar antigenic determinant were differently affected by injection of antigen in the neonatal period.

The finding that delayed hypersensitivity and antibody formation could be dissociated by the induction of immunologic tolerance supports the assumption that delayed hypersensitivity and antibody formation are different immune processes which are not necessarily linked together.
SPLEEN CELL PROLIFERATION IN RESPONSE TO HOMOLOGOUS ANTIGENS STUDIED IN CONGENIC RESISTANT STRAINS OF MICE
Authors: Dutton Richard W.
Published: June 2004

The proliferative responses obtained when spleen cell suspensions from two different inbred strains of mice were mixed were investigated further using congenic resistant strain pairs.

Strong responses were obtained in 9 cases out of 12 where the two strains differed at a single gene locus controlling an H-2 histocompatibility antigen. No responses were obtained where the difference occurred at loci controlling weak histocompatibility antigens.

These findings have been taken to provide additional circumstantial evidence that the response represents an in vitro homograft reaction to homologous tissue antigens.
IMMUNOGLOBULIN ISOANTIGENS (ALLOTYPES) IN THE MOUSE
Authors: Warner Noel L. , Herzenberg Leonard A. , Goldstein Gideon
Published: June 2004

Further analysis of the isoantigens (allotypes) of 2 classes of normal mouse immunoglobulins, γG2a and γG2b, has shown a minimum of 10 specificities for the Ig-1 locus (controlling γG2a-antigens) and 3 specificities for the Ig-3 locus (controlling γG2b-antigens).

Three γG2-myeloma proteins of plasma cell tumors induced in (NZB x BALB/c)F1 mice have been analyzed for the isoantigens they carry. NZB mice are genotypically Ig-1e Ig-3e, while BALB/c are Ig-1a Ig-3a. Two of the myeloma proteins are γG2a-globulins. One of these, GPC-7, carries all the isoantigenic specificities of the Ig-1e allele while the other, GPC-8, carries all the isoantigenic specificities of the Ig-1a allele. Thus only one of the parental alleles of the mouse in which the tumor arose is expressed in each of these myeloma proteins.

The third myeloma protein GPC-5, also carries the antigens of only one parental strain (NZB). However GPC-5, a γG2b-globulin, carries only one of the Ig-3 specificities normally associated with γG2b-globulins of NZB. Most remarkably it also carries one Ig-1 specificity normally associated with γG2a-globulins of NZB. This is the first analyzed mouse myeloma shown (a) to express some but not all the antigenic specificities normally associated with an allele and (b) to carry antigenic specificities controlled by two distinct immunoglobulin loci. The implications of these findings are discussed in relation to the genetic control of immunoglobulins.
THE ANTIGENIC DETERMINANTS OF THE PROTEIN-POLYSACCHARIDES OF CARTILAGE
Authors: Sandson John , Rosenberg Lawrence , White David
Published: June 2004

1. Protein-polysaccharides isolated from bovine, human, and porcine cartilage are antigenic in the rabbit.

2. PP-L from each of these species contains a minimum of two antigenic determinants; one is species specific, and one is common to all three species. Human PP-H also contains these two determinants.

3. Both antigenic determinants are in, or closely associated with, the protein moiety of the compound. Chondroitin sulfate and keratan sulfate were not demonstrated to be antigenic in these studies.
THE CAPSULAR POLYSACCHARIDE OF PNEUMOCOCCUS TYPE IX
Authors: Rao C. V. N. , Heidelberger Michael
Published: June 2004

The capsular polysaccharide of Type IX pneumococcus contains D-glucose, N-acetyl-D-glucosamine, and D-glucuronic acid. Complete hydrolysis is difficult. All of the N-acetylglucosamine is resistant to oxidation by periodate, but the other two sugars are degraded in part. Chemical and quantitative serological data are consistent with the linkage of two D-glucose residues 1 → 4, as in maltose; others may be linked 1 → 3. Part, at least, of the glucuronic acid and N-acetylglucosamine is linked to glucose.
RABBIT ANAPHYLACTIC ANTIBODY
Authors: Zvaifler Nathan J. , Becker Elmer L.
Published: June 2004

Antibody capable of sensitizing rabbit skin for passive cutaneous anaphylaxis is produced in the rabbit as early as 6 to 7 days following antigenic stimulation. It reaches peak activity around the 9th day and is gone by the 3rd wk. The antibody is heat labile, sensitive to treatment with mercaptoethanol, non-precipitating and does not fix complement. In order to demonstrate PCA activity a latent period is required of from 48 to 72 hr after introduction of the antibody into the rabbit's skin; the activity can persist for at least 17 days. It has a faster electrophoretic mobility than rabbit γG-globulin, and is eluted somewhat earlier than γG-globulin from Sephadex G-200, although distinctly after γM-globulin.

No relationship was demonstrated between the rabbit PCA activity and the hemagglutinating activity found in the same sera. The rabbit anaphylactic antibody differs in almost all properties studies from the rabbit 7S antibody capable of sensitizing guinea pigs for PCA which arises at the same time. This latter antibody found early in immunization had properties which were indistinguishable from those described for the rabbit 7S antibody giving PCA in the guinea pig found in late hyperimmune sera.
QUANTITATIVE STUDIES OF THE ADOPTIVE IMMUNOLOGICAL MEMORY IN MICE
Authors: Celada Franco
Published: June 2004

Antibody-forming cells suspended from a mouse spleen and transferred to intact animals of the same genotype face a barrier which severely affects their capacity to implant and/or to function.

This phenomenon was quantitatively studied in a model system which, utilizing the immunogenic properties of human serum albumin in mice, allows the secondary response of the transferred cells to be followed without interference from the host's own reactivity. The barrier to syngeneic transplantation was found (a) to be radiosensitive (500 R X-rays to the recipient abolishes it and insures optimal functional conditions to the donor cells) in the same order of magnitude of other mammalian systems involving rapidly dividing cell populations, and (b) to depend upon the age of the recipient: its linear rise is documented from birth time (when ∼50% of the maximal immune capacity of the transfer is expressed) to the age of 2 months (∼ 1 %). The significance of these findings to the immune response and to cell growth and differentiation is discussed.
RECOMBINATION OF HEAVY AND LIGHT CHAINS OF HUMAN γA-MYELOMA PROTEINS: FORMATION OF HYBRID MOLECULES AND CONFIGURATIONAL SPECIFICITY
Authors: Prendergast Robert A. , Grey Howard M. , Kunkel Henry G.
Published: June 2004

The present studies demonstrate that the conditions necessary for reductive cleavage, isolation, and recombination of L and H polypeptide chains of human γA-myeloma globulins parallel those required for similar manipulation of the component chains of γG-globulin. Specificity of recombination was shown for chains derived from the same protein. In contrast, no intradass preferential recombination was demonstrable.

Hybrid molecules, formed by reassociation of noncovalent bonds, could be synthesized from isolated chains of two immunoglobulin classes resulting in the formation of molecules of the type γA-H-γG-L and γG-H-γA-L.

Several sera containing both γA- and γG-"monoclonal" peaks were studied, one of which demonstrated the L chains associated with both peaks to be identical both by electrophoretic mobility in acid-urea gel and antigenic analysis. The possibility is considered that this case represents a naturally occurring analogue of the artificially produced hybrid molecules described in this study.

Configurational antigenic specificity of γA-myeloma proteins, imposed by the presence of kappa L chains in native and appropriately recombined molecules, provides a further indication of the importance of noncovalent bonds in the establishment of the quaternary structure of these proteins.