The structure and phase diagram of Langmuir films of alcohols on mercury

The coverage-dependent phase behavior of molecular films of alcohols (CH3(CH2)n-2CH2OH, denoted as CnOH) on mercury was studied for chain lengths 8 < or = n < or = 28, using surface tensiometry and surface specific X-ray methods. Phases with surface-normal-oriented molecules are found at high coverage, showing the CS, S, and LS phases found also on water. Phases comprising surface parallel molecules, which do not exist on water, are found here at low coverage. For the lowest coverage a two-dimensional gas phase is found, followed, upon increasing the coverage, by an n-dependent sequence of condensed phases of up to four layers of surface-parallel molecules before converting to the surface-normal phases. In contrast with the surface-normal phases, all of the surface-parallel phases are found to lack long-range order in the surface-parallel direction. Adsorption energies are derived from the phase diagram for the alkyl chain and the alcohol headgroup.

Fatty acid Langmuir films on liquid mercury: X-ray and surface tension studies

The structure and phase behavior of liquid-mercury-supported molecular films of fatty acids (CH3(CH2)n-2COOH, denoted CnOOH) were studied for molecular lengths 7 < or = n < or = 24, by surface tensiometry and X-ray methods. Two qualitatively different film structures were found, depending on coverage. For high coverage, the film consists of a monolayer of roughly surface-normal molecules, showing a pressure-dependent sequence of structures similar, though not identical, to that of the corresponding water-supported Langmuir films. At low coverage, phases consisting of surface-parallel molecules are found, not observed on the aqueous subphases employed to date. In this range, a two-dimensional (2D) gas followed by a single and, for 14 < or = n < or = 24, also by a double layer of surface-parallel molecules is found as coverage is increased. Depending on chain length, the flat-lying phases have a crystalline 2D-ordered, a smectic-like 1D-ordered, or a disordered in-plane structure consisting of molecular dimers. The structure and thermodynamics of the films are discussed.

The autoimmune lymphoproliferative syndrome (Canale?Smith) in adulthood

The autoimmune lymphoproliferative syndrome (ALPS) or Canale-Smith syndrome is a recently described clinical entity consisting of chronic, non-malignant lymphadenopathy and hepatosplenomegaly together with hypergammaglobulinemia, positive autoantibodies and/or overt autoimmune diseases. It is caused by a genetic defect in the mechanism of programmed cell death (apoptosis) and is characterized by the presence of double-negative (TCR alpha/beta CD4- CD8-) T lymphocytes (DNT). Although well known in pediatric patients, ALPS is an unusual diagnosis in adults. The oldest reported patient was aged 54. We describe another two adult patients in whom a presenting autoimmune disease led to the diagnosis of ALPS.

Surface and bulk interchange energy in binary mixtures of chain molecules

The interchange (interaction) parameter, controlling the phase behaviour of a binary mixture, is determined for the bulk and the surface of binary mixtures of different types of chain molecules, using surface tensiometry and a mean-field theory. For all mixtures and concentrations studied an identical behaviour is observed at the surface, depending only on the square of the reduced chain length mismatch delta n/n, where delta n and dealta n are the difference in and average of the number of carbons of the two components.

X-Ray Spectrometry of Copper: New Results on an Old Subject

We review recent, and some less recent, measurements of several emission spectra of copper. The results are discussed with special emphasis on elucidating the structure of the Kα 1,2 and Kβ 1,3 diagram lines and their underlying transitions. These lines are found to contain ≈30 % contribution from 3d spectator hole transitions. Other multielectronic transitions, the 2p spectator hole (satellites) and 1s spectator hole (hypersatellites) transitions were also measured. They are discussed paying special attention to the evolution of the lineshapes and intensities from the excitation threshold to saturation. Trends in the measured quantities depending on the spectator hole's shell and subshell are also discussed.

Antineutrophil cytoplasmic autoantibodies penetrate into human polymorphonuclear leukocytes and modify their apoptosis

OBJECTIVE

The interaction of extracellular anti-neutrophil cytoplasmic autoantibodies (ANCA) with neutrophilic granules may play an important role in the pathogenesis of ANCA-related disorders. It has been confirmed that apoptosis is an essential trigger associated with translocation of the cytoplasmic granules to the cell surface, and with the expression of ANCA antigens. Since cell penetration by autoantibodies and apoptosis may be associated processes, we tested the hypothesis that penetration of ANCA-autoantibodies into polymorphonuclear leukocytes (PMNs) has an effect on apoptosis and thereby can influence surface antigen expression.

METHODS

PMNs were isolated from the blood of healthy volunteers and incubated in the presence of anti-proteinase3 (PR3) enriched IgG or normal human IgG. For each period of incubation (40 minutes or 12 hours) we evaluated: 1) PMN morphology by light microscopy (LM) and transmission electron microscopy (TEM) for general estimation of the apoptotic process, and 2) ANCA binding to the target antigen by immunogold electron microscopy (IgEM).

RESULTS

Both normal and anti-PR3 IgG penetrate PMNs. The labeled PR3-ANCA were localized on PR3 granules, regardless of the granules' location within the cell, and in the sites where the PMN destruction processes were most expressed. The destructive processes showed extensive apoptotic characteristics, in contrast to PMNs penetrated by normal IgG.

CONCLUSION

PR3 ANCA penetrate PMNs and, via the interaction between PR3-ANCA and PR3-containing granule components, initiate a modification of the apoptotic process.

Diagram X-ray emission spectra of a hollow atom: the Kh alpha1,2 and Kh beta1,3 hypersatellites of Fe

High-resolution Fe K(h) beta(1,3) and K(h) alpha(1,2) hypersatellite spectra were measured, using monochromatized synchrotron radiation photoexcitation. The lines' energies, splitting, excitation thresholds, and the K(h) alpha(1)/K(h) alpha(2) intensity ratio were derived with high accuracy. Having both spectra, not hitherto available for any atom with high resolution, allows separating out the energy shifts of the outer levels caused by a K shell spectator vacancy. Comparison with ab initio relativistic multiconfigurational Dirac-Fock calculations reveals that while the influence of relativity and QED effects is mostly accounted for, discrepancies remain in the lines' intensity ratio, which sensitively measures the intermediacy of the coupling. Similar discrepancies, of unknown origin, are found in the energy shifts of the outer levels due to the final-state K shell spectator vacancy.

Surface freezing in binary mixtures of chain molecules. I. Alkane mixtures

X-ray surface scattering and surface tension measurements are used to study surface freezing in molten mixtures of alkanes. These binary mixtures consist of protonated and deuterated alkanes, as well as of alkanes of different lengths. As for pure alkanes, a crystalline monolayer is formed at the surface a few degrees above the bulk freezing temperature. The structure of the monolayer has been determined on an angstrom scale. A simple theoretical approach is used to account for the thermodynamical observations at the surface and in the bulk. The model is based on a competition between entropic mixing and a repulsive interaction due to chain-length mismatch. The surface and bulk liquid phases are treated as ideal mixtures, while the solid phases are treated as regular mixtures. The theory is found to account well for all the mixtures studied, both hydrogenated-hydrogenated and hydrogenated-deuterated. The repulsive interaction and its dependence on the chain lengths of the components are determined from fits to the measured data.

Surface freezing in binary mixtures of chain molecules. II. Dry and hydrated alcohol mixtures

Surface freezing is studied in dry and hydrated alcohol mixtures by surface x-ray scattering and surface tension measurements. A crystalline bilayer is formed at the surface a few degrees above the bulk freezing temperature. The packing is hexagonal, with molecules aligned along the surface normal in all cases. The in-plane lattice constant reveals a qualitatively different behavior with composition for hydrated and dry mixtures. The simple theoretical approach used successfully for alkane and deuterated alkane mixtures accounts well also for the alcohol mixtures. The repulsive length-mismatch term opposing the mixing entropy term in the free energy of the mixtures is shown to have a universal behavior for all mixtures studied: protonated alkanes, deuterated alkanes, and dry and wet alcohols. This universality is somewhat counterintuitive in view of the different interactions (e.g., hydrogen bonding in alcohols) in the different mixtures.

Fulminant Mycoplasma pneumoniae infection with multi-organ involvement: a case report

A 50-year-old man with no medical history was admitted because of progressive respiratory distress, aseptic meningitis, disseminated intravascular coagulation, cholestatic hepatitis, and renal failure. Mycoplasma pneumoniae infection was confirmed serologically. The patient was treated with erythromycin and showed a favorable recovery. Although M. pneumoniae infection is usually a benign, self-limited acute respiratory disease, on rare occasions it can manifest itself with a fulminant course and multi-organ involvement, even in normal healthy individuals.

The influence of different cultivating conditions on polymorphonuclear leukocyte apoptotic processes in vitro, I: the morphological characteristics of PMN spontaneous apoptosis

Polymorphonuclear leukocyte (PMN) populations incubated in vitro with normal human serum are save-regulated systems of spontaneous apoptosis. Light microscopy (LM), transmission (TEM), and scanning (SEM) electron microscopes were used for the evalution of PMN apoptopic alteration. Twelve-hour PMN populations were represented by optimal number of normal and different apoptotic forms. Their ultrastructural analysis showed that on this background, 3 apoptotic cell lines (code named "first," "second," and "third") were predominated. The following characteristics were featured: "first"--vacuolization of same organelles, release of their content outside, increase of general cytoplasmic density, nuclear filling with condensed chromatin, and formation of PMNs mainly into small, round, dense forms; "second"--involvement of micronuclei or nuclei in apoptosis, their displacement to the cytoplasmic membrane and separation from the cells, and cytoplasm had numerous intact granules almost until the completion of apoptosis; "third"--synchronous apoptotic process of the nuclei and cytoplasm, moderate electronic density of cytoplasm, and granular translocation to the cell surface. Secondary necrosis was completed mainly in the apoptotic process of the "second" and "third" lines. SEM surfaces confirmed the results of TEM. This research showed that neutrophil spontaneous apoptosis is a complicated process. The 3 apoptotic cell lines reflect different pathways characteristic for the studied systems under certain conditions of cultivation.

Structure of a Langmuir film on a liquid metal surface

The structure of organic monolayers on liquid surfaces depends sensitively on the details of the molecular interactions. The structure of a stearic acid film on a mercury surface was measured as a function of coverage with angstrom resolution. Unlike monolayers on water, the molecules were found here to undergo a transition from surface-parallel to surface-normal orientation with increasing coverage. At high coverage, two condensed hexatic phases of standing-up molecules were found. At low coverage, a two-dimensional (2D) gas phase and condensed single- and double-layered phases of flat-lying molecular dimers were revealed, exhibiting a 1D longitudinal positional order. This system should provide a broader tunability range for nanostructure construction than solid-supported self-assembled monolayers.

Demixing transition in a quasi-two-dimensional surface-frozen layer

A thin/thick transition was observed by x-ray reflectivity in a surface-frozen crystalline bilayer on the surface of a molten binary mixture of long alcohols. This rare example of a solid-solid phase transition in a quasi-2D system is shown to result from an abrupt temperature-driven change in the layer's composition, kinetically enabled by the layer's ability to exchange molecules with the underlying 3D liquid bulk. Mean-field thermodynamics yields a Gibbs-adsorption-like expression which accounts very well for the transition.

Tetra point wetting at the free surface of liquid Ga-Bi

A continuous surface wetting transition, pinned to a solid-liquid-liquid-vapor tetra coexistence point, is studied by x-ray reflectivity in liquid Ga-Bi binary alloys. The short-range surface potential is determined from the measured temperature evolution of the wetting film. The thermal fluctuations are shown to be insufficient to induce a noticeable breakdown of mean-field behavior, expected in short-range-interacting systems due to their d(u) = 3 upper critical dimensionality.