Introductions to the Community: Early-Career Researchers in the Time of COVID-19

COVID-19 has unfortunately halted lab work, conferences, and in-person networking, which is especially detrimental to researchers just starting their labs. Through social media and our reviewer networks, we met some early-career stem cell investigators impacted by the closures. Here, they introduce themselves and their research to our readers

Voltammetric Study for the Determination of Diclofenac in Aqueous Solutions Using Electro-Activated Carbon Electrodes

Diclofenac (DCF) is a nonsteroidal anti-inflammatory drug to treat pain and inflammatory diseases. The high consumption of the drug leads to a significant change in the ecosystem. With the aim of optimizing a fast screening analysis for DCF detection on many samples with a sensitive and cheap procedure, we considered electrochemical methods using carbon-based electrodes as sensors. The electrochemical behavior of the DCF was studied on glassy carbon electrodes (GCE) and on screen-printed carbon electrodes (SPCEs) from two different suppliers after an anodic activation. The surface of the SPCEs was analyzed by scanning electron microscope (SEM) and Energy Dispersive Spectrometry (EDS). On all the activated electrodes, the voltammetric procedure (Differential Pulse Voltammetry) for the determination of DCF was optimized by the Experimental Design method, and the linearity range of the response, as well as the calibration and limit parameters (limits of detection—LoD; limit of quantification—LoQ), were defined. Analyses on SPCEs were performed both by immersing the electrode in the solution and by deposing a drop of solution on the electrode. DCF signals are stabilized by the polishing process and enhanced by the anodic activation and acid pH. The electrochemical response of DCF is not reversible, and its by-products tend to be adsorbed on the surfaces, particularly on GCE. The lowest limit parameters were obtained using the GCE (LoD = 1.6 µg L−1) and the SPCE, having the smallest surface, immersed in solution (LoD = 7 µg L−1)

One Soul and Several Faces of Evaporative Dry Eye Disease

The ocular surface system interacts with, reacts with, and adapts to the daily continuous insults, trauma, and stimuli caused by direct exposure to the atmosphere and environment. Several tissue and para-inflammatory mechanisms interact to guarantee such an ultimate function, hence maintaining its healthy homeostatic equilibrium. Evaporation seriously affects the homeostasis of the system, thereby becoming a critical trigger in the pathogenesis of the vicious cycle of dry eye disease (DED). Tear film lipid composition, distribution, spreading, and efficiency are crucial factors in controlling water evaporation, and are involved in the onset of the hyperosmolar and inflammatory cascades of DED. The structure of tear film lipids, and subsequently the tear film, have a considerable impact on tears’ properties and main functions, leading to a peculiar clinical picture and specific management

RENAL DENERVATION RAPIDLY RESTORES CIRCULATING PROGENITOR CELLS IN PATIENTS AFFECTED BY RESISTANT HYPERTENSION

Objective: To investigate whether blood pressure (BP) lowering after renal sympathetic denervation (RSD) affects CD34+ cell number in drug-resistant hypertension (R-HTN). Design and method: We enrolled 11 patients with R-HTN, already treated with at least 6 antihypertensive drugs, including a diuretic, at full dosages; patients with offi ce BP of > 160 mmHg (>150 mmHg for type 2 diabetes) were considered eligible for the procedure. Adherence to drug treatment was accurately checked by patient’s general practitioners. Mean age was 61 ± 7.9 years; M: F 8:5. We measured clinic (sphygmomanometer) and ambulatory (Tonoport V GEHealthcare) BP, and heart rate (HR; electrocardiogram), at baseline and 30 days after RSD procedure (Symplicity; Medtronic). 24 h BP recordings and home BP protocols were consulted in addition to offi ce BP measurements at the hospital before enrollment. Results: At T0: SBP: 179.1 ± 9.3mmHg; DBP: 101.2 ± 5.5 mmHg; HR 79.9 ± 9.4; CD34+ cells: 1.66 ± 0.51. At T1 SBP values were reduced on the average of 40.2 mmHg (138.9 ± 7.3; –22.5%, p < 0.001) DBP of 18 mmHg (83.2 ± 3.2; –17.7%, p < 0.001), and HR of 10.4 bpm (67.3 ± 6.0; -17.7%, p < 0.005), and CD34+cell number increased on an average of 0.34 cells /microL (2.0 ± 0.51; +21.2%, p < 0.001). Conclusions: RSD rapidly restores CD34+cell number in patients affected by true R-HTN; if these results will be confi rmed on a larger scale, they could provide new insights about CD34+ cells and pathophysiological aspects of arterial hypertension

Multiwavelength Observations of the Runaway Binary HD 15137

HD 15137 is an intriguing runaway O-type binary system that offers a rare opportunity to explore the mechanism by which it was ejected from the open cluster of its birth. Here we present recent blue optical spectra of HD 15137 and derive a new orbital solution for the spectroscopic binary and physical parameters of the O star primary. We also present the first XMM-Newton observations of the system. Fits of the EPIC spectra indicate soft, thermal X-ray emission consistent with an isolated O star. Upper limits on the undetected hard X-ray emission place limits on the emission from a proposed compact companion in the system, and we rule out a quiescent neutron star in the propellor regime or a weakly accreting neutron star. An unevolved secondary companion is also not detected in our optical spectra of the binary, and it is difficult to conclude that a gravitational interaction could have ejected this runaway binary with a low mass optical star. HD 15137 may contain an elusive neutron star in the ejector regime or a quiescent black hole with conditions unfavorable for accretion at the time of our observations.Comment: Accepted to A

Spectroscopic Hα and Hγ survey of field Be stars: 2004-2009

Massive O- and B-type stars are cosmic engines in the Universe and can be the dominant source of luminosity in a galaxy. The class of Be stars are rapidly rotating B-type stars that lose mass in an equatorial, circumstellar disk (Porter & Rivinius 2003) and cause Balmer and other line emission. Currently, we are unsure as to why these stars rotate so quickly but three scenarios are possible: they may have been born as rapid rotators, spun up by binary mass transfer, or spun up during the main-sequence evolution of B stars. In order to investigate these scenarios for this population of massive stars, we have been spectroscopically observing a set of 115 field Be stars with the Kitt Peak Coudè Feed telescope in both the Hα and Hγ wavelength regimes since 2004. This time baseline allows for examination of variability properties of the circumstellar disks as well as determine candidates for closer examination for binarity. We find that 90% of the observed stars show some variability with 8% showing significant variability over the 5-year baseline. Such values may be compared with the significant variability seen in some clusters such as NGC 3766 (McSwain 2008). Also, while ~20% of the sample consists of known binaries, we find that another 15-30% of the sample shows indications of binarity. © International Astronomical Union 2011

Fermi LAT Observations of LS I +61 303: First detection of an orbital modulation in GeV Gamma Rays

This Letter presents the first results from the observations of LSI +61 303 using Large Area Telescope data from the Fermi Gamma-Ray Space Telescope between 2008 August and 2009 March. Our results indicate variability that is consistent with the binary period, with the emission being modulated at 26.6 +/- 0.5 days. This constitutes the first detection of orbital periodicity in high-energy gamma rays (20 MeV-100 GeV, HE). The light curve is characterized by a broad peak after periastron, as well as a smaller peak just before apastron. The spectrum is best represented by a power law with an exponential cutoff, yielding an overall flux above 100 MeV of 0.82 +/- 0.03(stat) +/- 0.07(syst) 10^{-6} ph cm^{-2} s^{-1}, with a cutoff at 6.3 +/- 1.1(stat) +/- 0.4(syst) GeV and photon index Gamma = 2.21 +/- 0.04(stat) +/- 0.06(syst). There is no significant spectral change with orbital phase. The phase of maximum emission, close to periastron, hints at inverse Compton scattering as the main radiation mechanism. However, previous very high-energy gamma ray (>100 GeV, VHE) observations by MAGIC and VERITAS show peak emission close to apastron. This and the energy cutoff seen with Fermi suggest the link between HE and VHE gamma rays is nontrivial.Comment: 7 pages, 5 figures, accepted for publication in ApJ Letters 21 July 200

Mechanisms of stretch-mediated skin expansion at single-cell resolution.

The ability of the skin to grow in response to stretching has been exploited in reconstructive surgery1. Although the response of epidermal cells to stretching has been studied in vitro2,3, it remains unclear how mechanical forces affect their behaviour in vivo. Here we develop a mouse model in which the consequences of stretching on skin epidermis can be studied at single-cell resolution. Using a multidisciplinary approach that combines clonal analysis with quantitative modelling and single-cell RNA sequencing, we show that stretching induces skin expansion by creating a transient bias in the renewal activity of epidermal stem cells, while a second subpopulation of basal progenitors remains committed to differentiation. Transcriptional and chromatin profiling identifies how cell states and gene-regulatory networks are modulated by stretching. Using pharmacological inhibitors and mouse mutants, we define the step-by-step mechanisms that control stretch-mediated tissue expansion at single-cell resolution in vivo.Wellcome Trust Royal Societ