Integrated Image and X-Ray Microanalysis of Hepatic Lysosomes in a Patient with Idiopathic Hemosiderosis Before and After Treatment by Phlebotomy

Morphometrical and X-ray elemental information was extracted from Scanning Transmission Electron Microscopy (STEM) images of hepatic lysosomes of a patient with idiopathic hemosiderosis before and after treatment by phlebotomy. The elements of interest were (i) iron, stored in pathological quantities in hepatic lysosomal structures and (ii) cerium, used as a capture ion after a cytochemical reaction to detect acid phosphatase activity in the lysosomal structures. Morphologically the lysosomal structures are heteromorph and the elements iron and cerium are heterogeneously distributed. With reduced raster (= reduced scanning area) analysis at 16 x 16 pixel points (integrating image and X-ray microanalysis), a marked difference in the area of the cross sectioned lysosomal structures before and after treatment could be demonstrated. Simultaneously the difference in the relative orientation of the elements iron and cerium before and after phlebotomy could be visualized. Chelex ion exchange beads, loaded with 11.5% w/w iron, and coembedded with the tissue blocks, were used as an internal standard. A mean iron peak to background ratio was obtained and a factor, converting ratio to absolute iron concentration, was calculated. The same calculation procedure, now per pixel point, was followed for the hepatic lysosomal structures. A marked difference in iron concentration in the individual lysosomal structures was observed before and after treatment by phlebotomy

Image Analysis and X-Ray Microanalysis in Cytochemistry

When cytochemical reaction products are homogeneously distributed within an organelle, point analyses suffice for the quantitative approach. However, quantitative analysis becomes tedious, when the elements in the reaction product are inhomogeneously distributed. Problems arise when elements from two reaction products have to be related to each other, or to endogenous cytological products (ferritin, haemosiderin, calcium, electron dense markers), either topographically or in concentration. When analyzing inhomogeneous/heteromorphical reaction product-containing organelles special attention has to be paid to measure and relate both volume and concentration. In this paper a relative simple structure (eosinophil granules) is chosen to demonstrate that the acquisition of the requested morphometrical plus chemical information and their integration is possible. The following points will be covered to acquire the morphometrical and chemical information: a). How to estimate the total cell cross-sectioned area. b). How to estimate the total cross-sectioned area of all reaction product-containing particles inside that cell. The ratio of these two areas will provide the requested information about the particle volume fraction. By using the X-ray detector in addition: c). How to acquire the chemical information at the requested resolution, within a reasonable total acquisition time d). How to integrate the morphometrical and chemical data per organelle, by matrix analysis in a reduced scan area. e). How to acquire quantitative chemical information, by the use of cross-sectioned standards. f). How to make this acquisition method independent from changes in the instrumental conditions during the acquisition

Gas Mass Fractions and the Evolution of LSB Dwarf Galaxies

The optical and HI properties for a sample of low surface brightness (LSB) dwarf galaxies, cataloged from the Second Palomar Sky Survey, is presented. Gas mass fractions for LSB dwarfs reach the highest levels of any know galaxy type (f_g=95%) confirming that their low stellar densities are due to inefficient conversion of gas mass into stellar mass. Comparison with star formation models indicates that the blue optical colors of LSB dwarfs is not due to low metallicity or recent star formation and can only be explained by a dominant stellar population that is less than 5 Gyrs in mean age. If star formation occurs in OB complexes, similar to normal galaxies, then LSB dwarfs must undergo weak bursts traveling over the extent of the galaxy to maintain their LSB nature, which contributes to their irregular morphological appearance.Comment: 23 pages AAS LaTeX, 7 figures, accepted for publication in A

Dissecting the luminosity function of the Coma cluster of galaxies using CFHT wide field images

[Abridged] We determined the luminosity function (LF) of the Coma cluster galaxies selected by luminosity, and the LF bi-variate in central brightness. The Coma cluster and control fields were imaged using the CFH12K (42x28 arcmin) and UH8K (28x28 arcmin) wide-field cameras at the CFHT. Selected HST images were used for testing. Quantities were derived from measurements in at least two colors, which have the following features: (1) Galaxies as faint as three times the luminosity of the brightest globular clusters are in the completeness region of our data. (2) We have a complete census (in the explored region) of low surface brightness galaxies with central surface brightness galaxies almost as low as the faintest so far cataloged ones. (3) The explored area is among the largest ever sampled with CCDs at comparable depth for any cluster of galaxies. (4) The error budget includes all sources of errors known to date. Using HST images we also discovered that blends of globular clusters, not resolved in individual components due to seeing, look like dwarf galaxies when observed from the ground and are numerous and bright. The derived Coma LF is relatively steep (alpha=-1.4) over the 11 magnitudes sampled, but the slope and shape depend on color. A large population of faint low surface brightness galaxies was discovered, representing the largest contributor (in number) to the LF at faint magnitudes. We found a clear progression for a faintening of the LF from high surface brightness galaxies (mu~20 mag/arcsec2) to galaxies of very faint central brightnesses (mu~24.5 mag/arcsec2), and some evidence for a steepening. Compact galaxies, usually classified as stars and therefore not included in the LF, are found to be a minor population in Coma.Comment: ApJ, in pres

Normal Globular Cluster Systems in Massive Low Surface Brightness Galaxies

We present the results of a study of the globular cluster systems of 6 massive spiral galaxies, originally cataloged as low surface brightness galaxies but here shown to span a wide range of central surface brightness values, including two intermediate to low surface brightness galaxies. We used the Advanced Camera for Surveys on board HST to obtain photometry in the F475W and F775W bands and select sources with photometric and morphological properties consistent with those of globular clusters. A total of 206 candidates were identified in our target galaxies. From a direct comparison with the Galactic globular cluster system we derive specific frequency values for each galaxy that are in the expected range for late-type galaxies. We show that the globular cluster candidates in all galaxies have properties consistent with globular cluster systems of previously studied galaxies in terms of luminosity, sizes and color. We establish the presence of globular clusters in the two intermediate to low surface brightness galaxies in our sample and show that their properties do not have any significant deviation from the behavior observed in the other sample galaxies. Our results are broadly consistent with a scenario in which low surface brightness galaxies follow roughly the same evolutionary history as normal (i.e. high surface) brightness galaxies except at a much lower rate, but require the presence of an initial period of star formation intense enough to allow the formation of massive star clusters.Comment: 14 pages, 6 figures. AJ accepte

Flavor decomposition of the sea quark helicity distributions in the nucleon from semi-inclusive deep-inelastic scattering

Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.Comment: 5 pages, 3 figure

Transverse-target-spin asymmetry in exclusive ω\omega-meson electroproduction

Hard exclusive electroproduction of $\omega$ mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive $\pi\omega$ transition form factor.Comment: DESY Report 15-14

Nuclear Polarization of Molecular Hydrogen Recombined on a Non-metallic Surface

The nuclear polarization of $\mathrm{H}_2$ molecules formed by recombination of nuclear polarized H atoms on the surface of a storage cell initially coated with a silicon-based polymer has been measured by using the longitudinal double-spin asymmetry in deep-inelastic positron-proton scattering. The molecules are found to have a substantial nuclear polarization, which is evidence that initially polarized atoms retain their nuclear polarization when absorbed on this type of surfac

First Measurement of the Tensor Structure Function b1b_1 of the Deuteron

The \Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of \Hera. The use of a tensor polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry \At and the tensor structure function \bd for average values of the Bj{\o}rken variable $0.01<0.45$ and of the squared four-momentum transfer $0.5 {\rm GeV^2} <5 {\rm GeV^2}$. The quantities \At and \bd are found to be non-zero. The rise of \bd for decreasing values of $x$ can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering

Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion ($\phi$) and the target spin axis ($\phi_S$) about the virtual photon direction and relative to the lepton scattering plane. The extracted Fourier component \cmpi is a signal of the previously unmeasured quark transversity distribution, in conjunction with the so-called Collins fragmentation function, also unknown. The Fourier component \smpi of the asymmetry arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson productio