Aspiration of biological viscoelastic drops

Spherical cellular aggregates are in vitro systems to study the physical and biophysical properties of tissues. We present a novel approach to characterize the mechanical properties of cellular aggregates using micropipette aspiration technique. We observe an aspiration in two distinct regimes, a fast elastic deformation followed by a viscous flow. We develop a model based on this viscoelastic behavior to deduce the surface tension, viscosity, and elastic modulus. A major result is the increase of the surface tension with the applied force, interpreted as an effect of cellular mechanosensing.Comment: 4 pages, 4 figures

The Spitzer Archival Far-InfraRed Extragalactic Survey

We present the Spitzer Archival Far-InfraRed Extragalactic Survey (SAFIRES). This program produces refined mosaics and source lists for all far-infrared extragalactic data taken during the more than six years of the cryogenic operation of the Spitzer Space Telescope. The SAFIRES products consist of far-infrared data in two wavelength bands (70 um and 160 um) across approximately 180 square degrees of sky, with source lists containing far-infrared fluxes for almost 40,000 extragalactic point sources. Thus, SAFIRES provides a large, robust archival far-infrared data set suitable for many scientific goals.Comment: 7 pages, 6 figures, published in ApJ

Measurement Reliability for Acupoint Activity Determined with the Prognos Ohmmeter

The concepts of meridians and acupoints are critical to traditional Chinese medicine but are met with skepticism in Western medicine. Empirical validation of these concepts is in its beginning stages and still hampered by problems with measurement. A promising avenue and foundation for validity testing is the demonstration that acupoint activity can be reliably measured via determination of electrical resistance at well-defined body surface points. In this article, efforts are described to maximize measurement reliability; we tested a variety of protocols to determine which method of data aggregation is associated with maximal reliability. Twenty-one healthy individuals were subjected to 5 repeated measurement cycles to test the predicted increase in reliability with increasing number of aggregated measurements. Reliability, defined as internal consistency, was indeed highest for 5 measurements (mean alpha = .88). Even the aggregate of only three measures was quite reliable (alpha = .84). Reliability for measuring acupoints on the left side of the body was roughly .05 higher than on the right side. Consistent with previous literature, we conclude that with repeated measures the reliability of electrical resistance measurements at acupoints is high and that a strong foundation for validation research is now laid

The Spitzer-IRAC/MIPS Extragalactic survey (SIMES) in the South Ecliptic Pole field

We present the Spitzer-IRAC/MIPS Extragalactic survey (SIMES) in the South Ecliptic Pole field. The large area covered (7.7 deg^2), together with one of the lowest Galactic cirrus emissions in the entire sky and a very extensive coverage by Spitzer, Herschel, Akari, and GALEX, make the SIMES field ideal for extragalactic studies. The elongated geometry of the SIMES area (≈4:1), allowing for significant cosmic variance reduction, further improves the quality of statistical studies in this field. Here we present the reduction and photometric measurements of the Spitzer/IRAC data. The survey reaches depths of 1.93 and 1.75 μJy (1σ) at 3.6 and 4.5 μm, respectively. We discuss the multiwavelength IRAC-based catalog, completed with optical, mid-, and far-IR observations. We detect 341,000 sources with F_(3.6µm) ⩾3σ. Of these, 10% have an associated 24 μm counterpart, while 2.7% have an associated SPIRE source. We release the catalog through the NASA/IPAC Infrared Science Archive. Two scientific applications of these IRAC data are presented in this paper. First, we compute integral number counts at 3.6 μm. Second, we use the [3.6]–[4.5] color index to identify galaxy clusters at z > 1.3. We select 27 clusters in the full area, a result consistent with previous studies at similar depth

The Additive Effects of Type-2 Diabetes on Cognitive Function in Older Adults with Heart Failure

Background. Medical comorbidity has been theorized to contribute to cognitive impairment in heart failure (HF) patients. Specifically, type-2 diabetes mellitus (T2DM), a common coexisting condition among HF patients, may be an independent predictor of cognitive impairment. Nonetheless, the relationships between T2DM and other risk factors for cognitive impairment among persons with HF are unclear. Methods. Persons with HF (N = 169, 34.3% women, age 68.57 ± 10.28 years) completed neuropsychological testing within a framework of an ongoing study. History of T2DM, along with other medical characteristics, was ascertained through a review of participants' medical charts and self-report. Results. Many participants (34.9%) had a comorbid T2DM diagnosis. After adjustment for demographic and medical characteristics, HF patients with T2DM evidenced significantly greater impairments across multiple cognitive domains than HF patients without T2DM: λ = .92, F(5, 156) = 2.82, P = .018. Post hoc tests revealed significant associations between T2DM and attention (P = .003), executive function (P = .032), and motor functioning (P = .008). Conclusion. The findings suggest additive contributions of T2DM and HF to impairments in attention, executive function, and motor function. Future work is needed to elucidate the mechanisms by which T2DM exacerbates cognitive impairment in HF

Ultradeep Spectroscopy with the Spitzer IRS

Mid-IR spectroscopy has detected the signatures of star-formation (PAH emission) in high redshift (z > 1) ultra- and hyper-luminous infrared galaxies. However, the study of the dominant population of IR-luminous galaxies (10^(11) - 10^(12) Lsun at 1 < z < 3), requires observation of sources a at the 0.1 mJy level. We present the deepest spectra taken to date in the Long-Low module of the the Infrared Spectrometer (IRS) on the Spitzer Space Telescope. We targeted two faint (~0.15 mJy) sources in the Southern GOODS field at z = 1.09 and z = 2.69 as likely star-forming galaxies. Spectra of the lower redshift target were taken in 8-21 micron range (short-low first order and long-low second order), while the higher redshift target was observed from 21-37 microns (longlow first order). Observing times were 3 and 9 hours on-source for SL-1 and LL-2, respectively, and 12 hours for LL-1. We also present the spectra of two serendipitous sources. We detect strong PAH emission in four targets. We compare the spectra to those of local galaxies observed by the IRS. The z = 1.09 source appears to be a typical, star-formation dominated LIRG, while the z = 2.69 source is a composite source with strong star formation and a prominent AGN. The AGN component dominates the IRAC colors of this source, obscuring the 1.6 μm “bump.” Such sources would be excluded from IRAC surveys for starbursts which might then underestimate the star formation density

Skin Impedance Measurements for Acupuncture Research: Development of a Continuous Recording System

Skin impedance at acupuncture points (APs) has been used as a diagnostic/therapeutic aid for more than 50 years. Currently, researchers are evaluating the electrophysiologic properties of APs as a possible means of understanding acupuncture's mechanism. To comprehensively assess the diagnostic, therapeutic and mechanistic implications of acupuncture point skin impedance, a device capable of reliably recording impedances from 100 kΩ to 50 MΩ at multiple APs over extended time periods is needed. This article describes design considerations, development and testing of a single channel skin impedance system (hardware, control software and customized electrodes). The system was tested for accuracy against known resistors and capacitors. Two electrodes (the AMI and the ORI) were compared for reliability of recording over 30 min. Two APs (LU 9 and PC 6) and a nearby non-AP site were measured simultaneously in four individuals for 60 min. Our measurement system performed accurately (within 5%) against known resistors (580 kΩ–10 MΩ) and capacitors (10 nF–150 nF). Both the AMI electrode and the modified ORI electrode recorded skin impedance reliably on the volar surface of the forearm (r = 0.87 and r = 0.79, respectively). In four of four volunteers tested, skin impedance at LU 9 was less than at the nearby non-AP site. In three of four volunteers skin impedance was less at PC 6 than at the nearby non-AP site. We conclude that our system is a suitable device upon which we can develop a fully automated multi-channel device capable of recording skin impedance at multiple APs simultaneously over 24 h