6,493 research outputs found

    Unexpected Test Results in a Patient with Multiple Myeloma

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    A 53-year-old male patient with an established diagnosis of IgG λ multiple myeloma was seen by a hematologist–oncologist in consultation from an outside hospital. He had previously received 1 cycle of chemotherapy treatment, but he was found to be intermittently noncompliant with his therapy. The patient reported occasional nosebleeds and fatigue. Except for a slightly cachectic appearance, the physical examination was unremarkable. Chemistry and hematology laboratory results are shown in Table 1. Serum protein electrophoresis revealed monoclonal paraproteinemia in high abundance marked by an intense band in the γ region. Immunofixation electrophoresis was not ordered at that time, but it was previously performed at another institution and was positive for IgG monoclonal protein. The attending pathologist noted the discrepancy between the presence of a monoclonal band by serum protein electrophoresis and the patient\u27s quantitative immunoglobulin measurements. Several additional suspicious test results were also noted

    Kinematic Masses of Super Star Clusters in M82 from High-Resolution Near-Infrared Spectroscopy

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    Using high-resolution (R~22,000) near-infrared (1.51 -- 1.75 microns) spectra from Keck Observatory, we measure the kinematic masses of two super star clusters in M82. Cross-correlation of the spectra with template spectra of cool evolved stars gives stellar velocity dispersions of sigma_r=15.9 +/- 0.8 km/s for MGG-9 and sigma_r=11.4 +/- 0.8 km/s for MGG-11. The cluster spectra are dominated by the light of red supergiants, and correlate most closely with template supergiants of spectral types M0 and M4.5. We fit King models to the observed profiles of the clusters in archival HST/NICMOS images to measure the half-light radii. Applying the virial theorem, we determine masses of 1.5 +/- 0.3 x 10^6 M_sun for MGG-9 and 3.5 +/- 0.7 x 10^5 M_sun for MGG-11. Population synthesis modelling suggests that MGG-9 is consistent with a standard initial mass function, whereas MGG-11 appears to be deficient in low-mass stars relative to a standard IMF. There is, however, evidence of mass segregation in the clusters, in which case the virial mass estimates would represent lower limits.Comment: 16 pages, 8 figures; ApJ, in pres

    Hot Stars and Cool Clouds: The Photodissociation Region M16

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    We present high-resolution spectroscopy and images of a photodissociation region (PDR) in M16 obtained during commissioning of NIRSPEC on the Keck II telescope. PDRs play a significant role in regulating star formation, and M16 offers the opportunity to examine the physical processes of a PDR in detail. We simultaneously observe both the molecular and ionized phases of the PDR and resolve the spatial and kinematic differences between them. The most prominent regions of the PDR are viewed edge-on. Fluorescent emission from nearby stars is the primary excitation source, although collisions also preferentially populate the lowest vibrational levels of H2. Variations in density-sensitive emission line ratios demonstrate that the molecular cloud is clumpy, with an average density n = 3x10^5 cm^(-3). We measure the kinetic temperature of the molecular region directly and find T_H2 = 930 K. The observed density, temperature, and UV flux imply a photoelectric heating efficiency of 4%. In the ionized region, n_i=5x10^3 cm^(-3) and T_HII = 9500 K. In the brightest regions of the PDR, the recombination line widths include a non-thermal component, which we attribute to viewing geometry.Comment: 5 pages including 2 Postscript figures. To appear in ApJ Letters, April 200

    Innovative design and construction methodologies for in-situ manufacturing of large sensorized structures in future human habitat on the Moon

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    Over 50 years have passed since humankind last walked on the Moon during the Apollo 17 mission, but space exploration is still among the most important challenges for our technological and scientific evolution. National space agencies identified Moon colonisation and the development of a sustainable lunar economy as top priorities for their programs. Exploiting in situ resources will be the enabling factor in this scenario for limiting Earth-dependability. Consequently, future outposts will require in situ sourced and processed materials. Furthermore, surface outpost maintenance activities will force settlers to build spare parts, day-use tooling, and safety-critical parts using local resources. Challenges and goals brought by the hostile lunar environment prompt disruptive design methods, and their novelty urges effective monitoring systems. This paper investigates how large structures of a foreseeable human lunar surface outpost can be realised, such as shells of habitation modules, landing pads, roads, and pavements. They require construction-scaled manufacturing technologies, thus moving beyond laboratory-scaled experiments but keeping robustness, low-power demand, automation, and adequacy to cope with the Moon extreme environment. The experience gained with compressed earth blocks and polymeric cement in terrestrial applications has driven the development of bricks made from regolith and scarce percentages of an organic phase. This solution has already demonstrated valuable flexural and compressive properties for construction manufacturing, also enabling the production of hollow bricks with inter lockable shapes. Interlocking bricks ease the assembly process and can be mortar-less. Hollows and cavities bring lightweight products, which further ease the assembly of large structures and reduce the amount of material to process; play a significant role in thermal insulation; pave the way towards instrumented and multifunctional parts. Indeed, the cavities can easily host Fiber Bragg Grating (FBG) sensors that evaluate strains, temperature, and humidity in real-time. This monitoring plays a significant role in safety as it allows constant tracking of the long-term effects of thermal vacuum and enables targeted maintenance. It also enables assessing the occurrence of micrometeoroid impacts on the structure, flagging whether this exceeded the designed impact strength. A reliable, fast, and automatable process for applying the fibres and the architecture monitoring solution is also discussed. The present research work aims to cast some light on disruptive designing and manufacturing methodologies for constructing smart habitat elements in permanent human lunar surface outposts

    Feedback in the Antennae Galaxies (NGC 4038/9): I. High-Resolution Infrared Spectroscopy of Winds from Super Star Clusters

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    We present high-resolution (R ~ 24,600) near-IR spectroscopy of the youngest super star clusters (SSCs) in the prototypical starburst merger, the Antennae Galaxies. These SSCs are young (3-7 Myr old) and massive (10^5 - 10^7 M_sun for a Kroupa IMF) and their spectra are characterized by broad, extended Br-gamma emission, so we refer to them as emission-line clusters (ELCs) to distinguish them from older SSCs. The Brgamma lines of most ELCs have supersonic widths (60-110 km/s FWHM) and non-Gaussian wings whose velocities exceed the clusters' escape velocities. This high-velocity unbound gas is flowing out in winds that are powered by the clusters' massive O and W-R stars over the course of at least several crossing times. The large sizes of some ELCs relative to those of older SSCs may be due to expansion caused by these outflows; many of the ELCs may not survive as bound stellar systems, but rather dissipate rapidly into the field population. The observed tendency of older ELCs to be more compact than young ones is consistent with the preferential survival of the most concentrated clusters at a given age.Comment: Accepted to Ap

    Infrared Spectroscopy of a Massive Obscured Star Cluster in the Antennae Galaxies (NGC 4038/4039) with NIRSPEC

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    We present infrared spectroscopy of the Antennae Galaxies (NGC 4038/4039) with NIRSPEC at the W. M. Keck Observatory. We imaged the star clusters in the vicinity of the southern nucleus (NGC 4039) in 0.39" seeing in K-band using NIRSPEC's slit-viewing camera. The brightest star cluster revealed in the near-IR (M_K(0) = -17.9) is insignificant optically, but coincident with the highest surface brightness peak in the mid-IR (12-18 micron) ISO image presented by Mirabel et al. (1998). We obtained high signal-to-noise 2.03 - 2.45 micron spectra of the nucleus and the obscured star cluster at R ~ 1900. The cluster is very young (4 Myr old), massive (16e6 M_sun), and compact (density ~ 115 M_sun pc^(-3) within a 32 pc half-light radius), assuming a Salpeter IMF (0.1 - 100 M_sun). Its hot stars have a radiation field characterized by T_eff ~ 39,000 K, and they ionize a compact H II region with n_e ~ 1e4 cm^(-3). The stars are deeply embedded in gas and dust (A_V ~ 9-10 mag), and their strong FUV field powers a clumpy photodissociation region with densities n_H >= 1e5 cm^(-3) on scales of up to 200 pc, radiating L[H_2 1-0 S(1)] = 9600 L_sun.Comment: 4 pages, 5 embedded figures. To appear in proceedings of 33d ESLAB Symposium: Star Formation from the Small to the Large Scale, held in Noordwijk, The Netherlands, Nov. 1999. Also available at http://astro.berkeley.edu/~agilber

    The Rest-Frame Optical Spectrum of MS 1512-cB58

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    Moderate resolution, near-IR spectroscopy of MS1512-cB58 is presented, obtained during commissioning of the the Near IR Spectrometer (NIRSPEC) on the Keck II telescope. The strong lensing of this z=2.72 galaxy by the foreground cluster MS1512+36 makes it the best candidate for detailed study of the rest-frame optical properties of Lyman Break Galaxies. A redshift of z=2.7290+/-0.0007 is inferred from the emission lines, in contrast to the z=2.7233 calculated from UV observations of interstellar absorption lines. Using the Balmer line ratios, we find an extinction of E(B-V)=0.27. Using the line strengths, we infer an SFR=620+/-18 Msun/yr (H_0=75, q_0=0.1, Lambda =0), a factor of 2 higher than that measured from narrow-band imaging observations of the galaxy, but a factor of almost 4 lower than the SFR inferred from the UV continuum luminosity. The width of the Balmer lines yields a mass of M_vir=1.2x10^10 Msun. We find that the oxygen abundance is 1/3 solar, in good agreement with other estimates of the metallicity. However, we infer a high nitrogen abundance, which may argue for the presence of an older stellar population.Comment: 14 pages, including 3 figures. Accepted for publication in ApJ Letter

    Mammary Extracellular Matrix Directs Differentiation of Testicular and Embryonic Stem Cells to Form Functional Mammary Glands In Vivo

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    Previously, we demonstrated the ability of the normal mammary microenvironment (niche) to direct non-mammary cells including testicular and embryonic stem cells (ESCs) to adopt a mammary epithelial cell (MEC) fate. These studies relied upon the interaction of transplanted normal MECs with non-mammary cells within the mammary fat-pads of recipient mice that had their endogenous epithelium removed. Here, we tested whether acellular mammary extracellular matrix (mECM) preparations are sufficient to direct differentiation of testicular-derived cells and ESCs to form functional mammary epithelial trees in vivo. We found that mECMs isolated from adult mice and rats were sufficient to redirect testicular derived cells to produce normal mammary epithelial trees within epithelial divested mouse mammary fat-pads. Conversely, ECMs isolated from omental fat and lung did not redirect testicular cells to a MEC fate, indicating the necessity of tissue specific components of the mECM. mECM preparations also completely inhibited teratoma formation from ESC inoculations. Further, a phenotypically normal ductal outgrowth resulted from a single inoculation of ESCs and mECM. To the best of our knowledge, this is the first demonstration of a tissue specific ECM driving differentiation of cells to form a functional tissue in vivo
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