Clonal expansion of human T lymphocytes initiated by dendritic cells

The accessory cell requirements for cloning T cells in the presence of lectin and T cell growth factors were examined with cells from human peripheral blood. We found that dendritic cells were active and perhaps essential. Single CD4+ lymphocytes could be cloned with 80% efficiency, and CD8+ cells with 50-60% efficiency if 103 syngeneic or allogeneic dendritic cells were added. Some T cell clones developed even with one dendritic cell. Monocytes or B lymphocytes from blood were at least 100-fold weaker in supporting clonal growth. These findings suggest a specialized feeder cell requirement, namely dendritic cells, for cloning T lymphocytes from single resting precursors

Atomic spectral-product representations of molecular electronic structure: metric matrices and atomic-product composition of molecular eigenfunctions

Recent progress is reported in development of ab initio computational methods for the electronic structures of molecules employing the many-electron eigenstates of constituent atoms in spectral-product forms. The approach provides a universal atomic-product description of the electronic structure of matter as an alternative to more commonly employed valence-bond- or molecular-orbital-based representations. The Hamiltonian matrix in this representation is seen to comprise a sum over atomic energies and a pairwise sum over Coulombic interaction terms that depend only on the separations of the individual atomic pairs. Overall electron antisymmetry can be enforced by unitary transformation when appropriate, rather than as a possibly encumbering or unnecessary global constraint. The matrix representative of the antisymmetrizer in the spectral-product basis, which is equivalent to the metric matrix of the corresponding explicitly antisymmetric basis, provides the required transformation to antisymmetric or linearly independent states after Hamiltonian evaluation. Particular attention is focused in the present report on properties of the metric matrix and on the atomic-product compositions of molecular eigenstates as described in the spectral-product representations. Illustrative calculations are reported for simple but prototypically important diatomic (H_2, CH) and triatomic (H_3, CH_2) molecules employing algorithms and computer codes devised recently for this purpose. This particular implementation of the approach combines Slater-orbital-based one- and two-electron integral evaluations, valence-bond constructions of standard tableau functions and matrices, and transformations to atomic eigenstate-product representations. The calculated metric matrices and corresponding potential energy surfaces obtained in this way elucidate a number of aspects of the spectral-product development, including the nature of closure in the representation, the general redundancy or linear dependence of its explicitly antisymmetrized form, the convergence of the apparently disparate atomic-product and explicitly antisymmetrized atomic-product forms to a common invariant subspace, and the nature of a chemical bonding descriptor provided by the atomic-product compositions of molecular eigenstates. Concluding remarks indicate additional studies in progress and the prognosis for performing atomic spectral-product calculations more generally and efficiently

Comment on "Critique of the foundations of time-dependent density functional theory" [Phys. Rev.A. 75, 022513 (2007)]

A recent paper (Phys. Rev A. 75, 022513 (2007), arXiv:cond-mat/0602020) challenges exact time-dependent density functional theory (TDDFT) on several grounds. We explain why these criticisms are either irrelevant or incorrect, and that TDDFT is both formally exact and predictive.Comment: 4 pages; This is a Comment on the paper cited above, also at arXiv:cond-mat/060202

Conflicto hidrosocial atuelino: ochenta años después ¿basta con que el agua fluya?

En esta ponencia se analizan los dilemas que plantea en la actualidad el conflicto hidrosocial por el río Atuel entre las provincias de La Pampa y Mendoza, Argentina, el cual se delinea como tal a mediados de la década del 40 del siglo pasado. Es uno de los pocos casos, sino el único, en el país donde aún se continúa — después de tanto tiempo— con un conflicto de estas características irresuelto. Esta disputa se da en un espacio semiárido, donde la cuenca atuelina, alimentada por precipitaciones nivales y glaciales básicamente, irriga parte del sur mendocino e ingresa a La Pampa, donde se une al tramo final de la cuenca del Desaguadero. El objetivo general del trabajo es poner en discusión si con el restablecimiento de las condiciones físicas del último tramo del río basta para solucionar el conflicto o es necesario considerar otros elementos, como los socioculturales.Instituto de Investigaciones en Humanidades y Ciencias Sociale

Ultrafast Radial Transport In A Micron‐Scale Aluminum Plasma Excited At Relativistic Intensity

Using femtosecond microscopy, we observe a thermal/ionization front expand radially at ∼108cm/s from a λ2‐size spot of an aluminum target excited at >1018W/cm2. Numerical modeling shows transport is predominantly radiative and may be initially nonlocal. © 2004 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87543/2/609_1.pd

The increasing trend in preterm birth in public hospitals in northern Argentina

Objective: To identify factors associated with the increasing incidence of preterm birth in northern Argentina. Methods: In an observational study, data were reviewed from a prospective, population-based registry of pregnancy outcomes in six cities in 2009-2012. The primary outcome was preterm birth (at 20-37 weeks). Bivariate tests and generalized estimating equations were used within a conceptual hierarchical framework to estimate the cluster-corrected annual trend in odds of preterm birth. Results: The study reviewed data from 11 433 live births. There were 484 (4.2%) preterm births. The incidence of preterm births increased by 38% between 2009 and 2012, from 37.5 to 51.7 per 1000 live births. Unadjusted risk factors for preterm birth included young or advanced maternal age, normal body mass index, nulliparity, no prenatal care, no vitamins or supplements during pregnancy, multiple gestation, and maternal hypertension or prepartum hemorrhage. The prevalence of many risk factors increased over the study period, but variations in these factors explained less than 1% of the increasing trend in preterm birth. Conclusion: The incidence of preterm births insix small cities in northern Argentina increased greatly between 2009 and 2012. This trend was unexplained by the risk factors measured. Other factors should be assessed in future studies.Fil: Weaver, Emily H.. University of North Carolina School at Chapel Hill; Estados UnidosFil: Gibbons, Luz. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Belizan, Jose. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Althabe, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Efectividad Clínica y Sanitaria; Argentin

Centrosymmetric molecules as possible carriers of diffuse interstellar bands

In this paper, we present new data with interstellar C2 (Phillips bands A-X), from observations made with the Ultraviolet-Visual Echelle Spectrograph of the European Southern Observatory. We have determined the interstellar column densities and excitation temperatures of C2 for nine Galactic lines. For seven of these, C2 has never been observed before, so in this case the still small sample of interstellar clouds (26 lines of sight), where a detailed analysis of C2 excitation has been made, has increased significantly. This paper is a continuation of previous works where interstellar molecules (C2 and diffuse interstellar bands) have been analysed. Because the sample of interstellar clouds with C2 has increased, we can show that the width and shape of the profiles of some diffuse interstellar bands (6196 and 5797 A) apparently depend on the gas kinetic and rotational temperatures of C2; the profiles are broader because of the higher values of the gas kinetic and rotational temperatures of C2. There are also diffuse interstellar bands (4964 and 5850 A) for which this effect does not exist.Comment: 8 pages, 4 figures, accepted to MNRAS 201