Portable dynamic fundus instrument

A portable diagnostic image analysis instrument is disclosed for retinal funduscopy in which an eye fundus image is optically processed by a lens system to a charge coupled device (CCD) which produces recordable and viewable output data and is simultaneously viewable on an electronic view finder. The fundus image is processed to develop a representation of the vessel or vessels from the output data

The Star Clusters in the Starburst Irregular Galaxy NGC 1569

We examine star clusters in the irregular, starburst galaxy NGC 1569 from HST images. In addition to the two known super star clusters, we identify 45 other clusters that are compact but resolved. Integrated UVI colors of the clusters span a large range, and suggest that ages range from 3 Myrs to 1 Gyr. However, most of the clusters were formed at the tail end of the recent starburst. Numerous clusters in addition to the know super star clusters are similar in luminosity to a small globular cluster. We examined the radial surface brightness of four of the clusters. Their half-light radii and core radii are in the range observed in present-day globular clusters. Therefore, conditions that produced the recent starburst have also been those necessary for producing compact, bright star clusters. We examine resolved stars in the outer parts of the two super star clusters. Cluster A is dominated by bright blue stars with a small population of red supergiants. Sub-components A1 and A2 have similar colors and a two-dimensional color map does not offer evidence that one component is dominated by red supergiants and the other not. The contradiction of the presence of red super- giants with Wolf-Rayet stars may instead not be a contradiction at all since there coexistence in a coeval population is not inconsistent with the evolution of massive stars. Cluster B is dominated by red supergiants, and this is confirmed by the presence of the stellar CO absorption feature in an integrated spectrum. The various age indicators are consistent with a picture in which cluster B is of order 10--20 Myrs old, and cluster A is >4-5 Myrs old.Comment: To be published in AJ, November 200

Insecure attachment is associated with the α-EEG anomaly during sleep

Abstract Background The α-EEG anomaly during sleep, originally associated with chronic pain, is noted in several psychiatric and medical conditions and is also present in some normal subjects. The exact significance of the α-EEG anomaly is uncertain, but it has been suggested to be a nonspecific response to a variety of noxious stimuli. We propose that attachment insecurity, which is often associated with a state of hypervigilance during wakefulness, may be associated with the α-EEG anomaly during sleep. Methods Thirty one consecutive patients referred to a Sleep Disorders Clinic for clinical assessment of sleep complaints underwent standard polysomnographic recording. The degree of alpha activity in polysomnographs was scored visually according to standard criteria. Attachment insecurity was measured with the Experience in Close Relationships – Revised questionnaire. Results Attachment anxiety was significantly associated with the proportion of sleep in which α waves were present (df = 1, F = 5.01, p = 0.03). The relationship between the α-EEG anomaly and attachment anxiety was not explained by the distribution of sleep and mood diagnoses, medications, anxiety symptoms or depression symptoms. Conclusion Interpersonal style in close relationships may be related to sleep physiology. Further research to determine the nature of the relationship between attachment, sleep and other factors that are related to each of these, such as a history of personal adversity, is warranted

Schwann cell mitochondrial metabolism supports long-term axonal survival and peripheral nerve function

Mitochondrial dysfunction is a common cause of peripheral neuropathies. While the role of neuron and axonal mitochondria in peripheral nerve disease is well appreciated, whether Schwann cell (SC) mitochondrial deficits contribute to peripheral neuropathies is unclear. Here we examine how SC mitochondrial dysfunction affects axonal survival and contributes to the decline of peripheral nerve function by generating mice with SC-specific mitochondrial deficits. These mice (Tfam-SCKOs) were produced through the tissue-specific deletion of the mitochondrial transcription factor A gene (Tfam), which is essential for mitochondrial DNA (mtDNA) transcription and maintenance. Tfam-SCKOs were viable but, as they aged, they developed a progressive peripheral neuropathy characterized by nerve conduction abnormalities as well as extensive muscle denervation. Morphological examination of Tfam-SCKO nerves revealed early preferential loss of small unmyelinated fibers followed by prominent demyelination and degeneration of larger-caliber axons. Tfam-SCKOs displayed sensory and motor deficits consistent with this pathology. Remarkably, the severe mtDNA depletion and respiratory chain abnormalities in Tfam-SCKO mice did not affect SC proliferation or survival. Mitochondrial function in SCs is therefore essential for maintenance of axonal survival and normal peripheral nerve function, suggesting that SC mitochondrial dysfunction contributes to human peripheral neuropathies

Fermi-LAT Sensitivity to Dark Matter Annihilation in Via Lactea II Substructure

We present a study of the ability of the Fermi Gamma-ray Space Telescope to detect dark-matter annihilation signals from the Galactic subhalos predicted by the Via Lactea II N-body simulation. We implement an improved formalism for estimating the boost factor needed to account for the effect of dark-matter clumping on scales below the resolution of the simulation, and we incorporate a detailed Monte Carlo simulation of the response of the Fermi-LAT telescope, including a simulation of its all-sky observing mode integrated over a ten year mission. We find that for WIMP masses up to about 150 GeV in standard supersymmetric models with velocity-averaged cross section 3*10^-26 cm^3 s^-1, a few subhalos could be detectable with >5 standard deviations significance and would likely deviate significantly from the appearance of a point source.Comment: 16 pages, 6 figure

Identification of intramembrane hydrogen bonding between 131 keto group of bacteriochlorophyll and serine residue α27 in the LH2 light-harvesting complex

AbstractIntramembrane hydrogen bonding and its effect on the structural integrity of purple bacterial light-harvesting complex 2, LH2, have been assessed in the native membrane environment. A novel hydrogen bond has been identified by Raman resonance spectroscopy between a serine residue of the membrane-spanning region of LH2 α-subunit, and the C-131 keto carbonyl of bacteriochlorophyll (BChl) B850 bound to the β-subunit. Replacement of the serine by alanine disrupts this strong hydrogen bond, but this neither alters the strongly red-shifted absorption nor the structural arrangement of the BChls, as judged from circular dichroism. It also decreases only slightly the thermal stability of the mutated LH2 in the native membrane environment. The possibility is discussed that weak H-bonding between the C-131 keto carbonyl and a methyl hydrogen of the alanine replacing serine(−4) or the imidazole group of the nearby histidine maintains structural integrity in this very stable bacterial light-harvesting complex. A more widespread occurrence of H-bonding to C-131 not only in BChl, but also in chlorophyll proteins, is indicated by a theoretical analysis of chlorophyll/polypeptide contacts at <3.5 Å in the high-resolution structure of Photosystem I. Nearly half of the 96 chlorophylls have aa residues suitable as hydrogen bond donors to their keto groups

Heterogeneity in ess transcriptional organization and variable contribution of the Ess/Type VII protein secretion system to virulence across closely related <em>Staphylocccus aureus </em>strains

The Type VII protein secretion system, found in Gram-positive bacteria, secretes small proteins, containing a conserved W-x-G amino acid sequence motif, to the growth medium. Staphylococcus aureus has a conserved Type VII secretion system, termed Ess, which is dispensable for laboratory growth but required for virulence. In this study we show that there are unexpected differences in the organization of the ess gene cluster between closely related strains of S. aureus. We further show that in laboratory growth medium different strains of S. aureus secrete the EsxA and EsxC substrate proteins at different growth points, and that the Ess system in strain Newman is inactive under these conditions. Systematic deletion analysis in S. aureus RN6390 is consistent with the EsaA, EsaB, EssA, EssB, EssC and EsxA proteins comprising core components of the secretion machinery in this strain. Finally we demonstrate that the Ess secretion machinery of two S. aureus strains, RN6390 and COL, is important for nasal colonization and virulence in the murine lung pneumonia model. Surprisingly, however, the secretion system plays no role in the virulence of strain SA113 under the same conditions

Suicide inhibition of alpha-oxamine synthases:structures of the covalent adducts of 8-amino-7-oxononanoate synthase with trifluoroalanine

The suicide inhibition of the α-oxamine synthases by the substrate analog, L-trifluoroalanine was investigated. The inhibition resulted in the formation of a complex with loss of all three fluorine atoms. Decarboxylation and loss of fluoride occurred immediately after aldimine formation. The inherent flexibility could allow the difluorinated intermediate complex to adopt a suitable conformation. Decarboxylation in the normal mechanism occurs after formation of the ketoacid intermediate.link_to_subscribed_fulltex

Low Metallicity Indicates that the Hypervelocity Star HE 0437-5439 was Ejected from the LMC

We measure the metallicity of the unusual hypervelocity star HE 0437-5439 from high resolution spectroscopy to be half-solar. We determine a spectral type of B2 IV-III for the star and derive an effective temperature Teff= 21,500 +/- 1,000 K and a surface gravity log(g) = 3.7 +/- 0.2 (cgs). We also present BV time series photometry and find the star to be non-variable at the 0.02 mag level. We refine the magnitude of the hypervelocity star to V=16.36+/-0.04 mag, with a color B-V=-0.23+/-0.03 mag, confirming its early-type nature. Our metallicity result establishes the origin of HE 0437-5439 in the Large Magellanic Cloud and implies the existence of a massive black hole somewhere in this galaxy.Comment: 12 pages, 3 figures, 1 table; accepted to ApJL. Added 2 coauthors & full abundance analysis. Results are strengthene