Exploring Galaxy Evolution from Infrared Number Counts and Cosmic Infrared Background

Recently reported infrared (IR) galaxy number counts and cosmic infrared background (CIRB) all suggest that galaxies have experienced a strong evolution sometime in their lifetime. We statistically estimate the galaxy evolution history from these data. We find that an order of magnitude increase of the far-infrared (FIR) luminosity at redshift z = 0.5 - 1.0 is necessary to reproduce the very high CIRB intensity at 140 um reported by Hauser et al. (1998). z \sim 0.75 and decreases to, even at most, a factor of 10 toward z \sim 5, though many variants are allowed within these constraints. This evolution history also satisfies the constraints from the galaxy number counts obtained by IRAS, ISO and, roughly, SCUBA. The rapid evolution of the comoving IR luminosity density required from the CIRB well reproduces the very steep slope of galaxy number counts obtained by ISO. We also estimate the cosmic star formation history (SFH) from the obtained FIR luminosity density, considering the effect of the metal enrichment in galaxies. The derived SFH increases steeply with redshift in 0 0.75. This is consistent with the SFH estimated from the reported ultraviolet luminosity density. In addition, we present the performance of the Japanese ASTRO-F FIR galaxy survey. We show the expected number counts in the survey. We also evaluate how large a sky area is necessary to derive a secure information of galaxy evolution up to z \sim 1 from the survey, and find that at least 50 - 300 deg^2 is required.Comment: 18 pages LaTeX, PASJ in press. Abstract abridge

Physiological Role of Alveolar Macrophage in Acute Lower Respiratory Tract Infection: Phagocytosis and Aging

Acute lower respiratory tract infections (LRTIs) are the deadliest communicable diseases. Inhaled pathogens that reach the alveoli are eliminated by lung-resident alveolar macrophages. Bacteria and fungi are detected and phagocytosed by specific pattern recognition receptors (PRRs) that are highly expressed in alveolar macrophages. In addition, early pro-inflammatory responses assist alveolar macrophages in the efficient phagocytosis of these pathogens. Viruses are also directly or indirectly endocytosed by pinocytosis or opsonization, respectively, whereas alveolar macrophages contribute to the prevention of pneumonia by removing endogenous dead cells through an alternate type of phagocytosis, efferocytosis. Macrophage phagocytosis and efferocytosis require not only sufficient expression of the relevant PRRs but also the coordinated interplay of intracellular factors that regulate engulfment. Given the current situation in which emerging infectious diseases spread worldwide, this chapter summarizes the physiological roles of alveolar macrophages in acute LRTIs, focusing on phagocytosis, pro-inflammatory responses, efferocytosis, and their regulatory machinery. This chapter also reviews recent insights into age-associated dysfunction of alveolar macrophages and discusses their relevance to vulnerability to acute LRTIs in the elderly population

The saw-tooth sign as a clinical clue for intrathoracic central airway obstruction

BACKGROUND: The saw-tooth sign was first described by Sanders et al in patients with obstructive sleep apnea syndrome as one cause of extrathoracic central airway obstruction. The mechanism of the saw-tooth sign has not been conclusively clarified. The sign has also been described in various extrathoracic central airway diseases, such as in burn victims with thermal injury to the upper airways, Parkinson’s disease, tracheobronchomalacia, laryngeal dyskinesia, and pedunculated tumors of the upper airway. CASE PRESENTATION: A 61-year-old man was referred to our hospital with a two-month history of persistent dry cough and dyspnea. He was diagnosed with lung cancer located in an intrathoracic central airway, which was accompanied by the saw-tooth sign on flow-volume loops. This peculiar sign repeatedly improved and deteriorated, in accordance with the waxing and waning of central airway stenosis by anti-cancer treatments. CONCLUSION: This report suggests that the so-called saw-tooth sign may be found even in intrathoracic central airway obstruction due to lung cancer

Compartmentalization of gold nanoparticle clusters in hollow silica spheres and their assembly induced by an external electric field

Assembly of plasmonic nanoparticle clusters having hotspots in a specific space is an effective way to efficiently utilize their plasmonic properties. In the assembly, however, bulk-like aggregates of the nanoparticles are readily formed by strong van der Waals forces, inducing a decrease of the properties. The present work proposes an advanced method to avoid aggregation of the clusters by encapsulating into a confined space of hollow silica interior. Hollow spheres incorporating gold nanoparticle clusters were synthesized by a surface-protected etching process. The observation of inner nanoparticles with liquid cell transmission electron microscopy experimentally proved that the nanoparticles moved as a cluster instead of as dispersed nanoparticles within the water-filled hollow compartment. The hollow spheres incorporating the nanoparticle clusters were assembled in the vicinity of electrodes by application of an external AC electric field, resulting in the enhancement of Raman intensities of probe molecules. The nanoparticle-cluster-containing hollow spheres were redispersed when the electric field was turned off, showing that the hollow silica spheres can act as a physical barrier to avoid the cluster aggregation. The Raman intensities were reversibly changed by switching the electric field on and off to control the assembled or dispersed states of the hollow spheres