The first CO+ image: Probing the HI/H2 layer around the ultracompact HII region Mon R2

The CO+ reactive ion is thought to be a tracer of the boundary between a HII region and the hot molecular gas. In this study, we present the spatial distribution of the CO+ rotational emission toward the Mon R2 star-forming region. The CO+ emission presents a clumpy ring-like morphology, arising from a narrow dense layer around the HII region. We compare the CO+ distribution with other species present in photon-dominated regions (PDR), such as [CII] 158 mm, H2 S(3) rotational line at 9.3 mm, polycyclic aromatic hydrocarbons (PAHs) and HCO+. We find that the CO+ emission is spatially coincident with the PAHs and [CII] emission. This confirms that the CO+ emission arises from a narrow dense layer of the HI/H2 interface. We have determined the CO+ fractional abundance, relative to C+ toward three positions. The abundances range from 0.1 to 1.9x10^(-10) and are in good agreement with previous chemical model, which predicts that the production of CO+ in PDRs only occurs in dense regions with high UV fields. The CO+ linewidth is larger than those found in molecular gas tracers, and their central velocity are blue-shifted with respect to the molecular gas velocity. We interpret this as a hint that the CO+ is probing photo-evaporating clump surfaces.Comment: The main text has 4 pages, 2 pages of Appendix, 4 figures, 1 table. Accepted for publication in Astronomy and Astrophysics letter

The Effect of Hydration Status on Sleep Quality: A Pilot Study

Sleep improves muscle recovery and cognitive health and can be impaired by physiological and mental stress. Dehydration can induce stress which leads to sleep impairment and thus could affect the readiness for and recovery from exercise. However, no study has examined the effect of hydration on sleep before and after resistance exercise (RE). PURPOSE: To examine the effect of hydration status on sleep before and after RE. METHODS: 7 resistance-trained men completed two identical RE consisting of bilateral leg press and knee extensions (5 sets of 10 repetitions at 80% of 1 repetition maximum) in a euhydrated state (EU; urine specific gravity (USG) \u3c 1.020) and in a dehydrated state (DE: USG ≥ 1.020). The two conditions were separated by 2 weeks in random order. During DE, participants underwent a 24-hr fluid restriction the day before RE and consumed only 1.5 L water following RE throughout the day. Participants wore a wearable sleep device, and sleep efficiency (SE), light sleep (LS), rapid eye movement (REM), and slow wave sleep (SWS) were measured the night before (PRE) and the night after (POST) RE. A 2X2 ANOVA and effect sizes (ES) were used to detect differences. RESULTS: No significant (p \u3e 0.05) condition x time effect was observed for any sleep parameters. At PRE, a small ES was observed for SE (1.1%; η2 = 0.05) where EU was more efficient than DE. Additionally, a medium ES was observed for LS (26.2%; η2 = 0.09) and SWS (8%; η2 = 0.08) where EU spent more time in these phases than DE, while EU spent less time in the REM phase (-16.4%; η2 = 0.07) than DE. At POST, a small ES was observed for SE (1.3%; η2 = 0.05) where EU was more efficient than DE. Additionally, a medium ES was observed for REM (-35.7%; η2 = 0.07) and SWS (-8.4%; η2 = 0.08) where EU spent less time in these phases than DE, while EU spent more time in the LS phase (18.7%; η2 = 0.09) than DE. CONCLUSION: The pilot data suggests hydration status could influence sleep. Proper fluid intake could help with sleep efficiency and increase time spent in LS and SWS, which are beneficial for muscle and tissue recovery. Intriguingly, inadequate fluid intake could increase the time spent in REM, which might be due to the mental and physical stresses from dehydration and RE. Combined, these data suggest that hydration status could affect the readiness for and recovery from physical stress

MicroRNA93 regulates proliferation and differentiation of normal and malignant breast stem cells

MicroRNAs (miRNAs) play important roles in normal cellular differentiation and oncogenesis. microRNA93 (mir-93), a member of the mir106b-25 cluster, located in intron 13 of the MCM7 gene, although frequently overexpressed in human malignancies may also function as a tumor suppressor gene. Using a series of breast cancer cell lines representing different stages of differentiation and mouse xenograft models, we demonstrate that mir-93 modulates the fate of breast cancer stem cells (BCSCs) by regulating their proliferation and differentiation states. In "claudin low" SUM159 cells, expression of mir-93 induces Mesenchymal-Epithelial Transition (MET) associated with downregulation of TGFβ signaling and downregulates multiple stem cell regulatory genes, including JAK1, STAT3, AKT3, SOX4, EZH1, and HMGA2, resulting in cancer stem cell (CSC) depletion. Enforced expression of mir-93 completely blocks tumor development in mammary fat pads and development of metastases following intracardiac injection in mouse xenografts. The effect of mir-93 on the CSC population is dependent on the cellular differentiation state, with mir-93 expression increasing the CSC population in MCF7 cells that display a more differentiated "luminal" phenotype. mir-93 also regulates the proliferation and differentiation of normal breast stem cells isolated from reduction mammoplasties. These studies demonstrate that miRNAs can regulate the states and fates of normal and malignant mammary stem cells, findings which have important biological and clinical implications. © 2012 Liu et al

A prospective comparison of three argatroban treatment regimens during hemodialysis in end-stage renal disease

A prospective comparison of three argatroban treatment regimens during hemodialysis in end-stage renal disease.BackgroundWe prospectively evaluated 3 treatment regimens of argatroban, a direct thrombin inhibitor, for providing adequate, safe anticoagulation in patients with end-stage renal disease (ESRD) during hemodialysis.MethodsIn this randomized, 3-way crossover study, ESRD patients underwent hemodialysis sessions of 3- or 4-hour duration using high-flux membranes and each of 3 argatroban treatment regimens (A: 250-μg/kg bolus, with an additional 250-μg/kg bolus allowed; B: 250-μg/kg bolus followed by 2-μg/kg/min infusion; C: steady-state, 2-μg/kg/min infusion initiated 4 hours before dialysis). Pharmacodynamic effects including activated clotting times (ACTs); hemodialysis efficacy including single-pool Kt/V, urea reduction ratio (URR), and circuit flow; and safety through a 3-day follow-up were monitored. Argatroban pharmacokinetic parameters including dialytic clearance were evaluated during regimen C.ResultsThirteen patients completed 38 hemodialysis sessions (1 patient withdrew consent after 2 sessions). Mean ± SD ACTs increased from 131 ± 14 seconds at baseline to 153 ± 24, 200 ± 30, and 197 ± 33 seconds, respectively, after 60 minutes of hemodialysis using regimens A, B, and C. Across regimens, mean Kt/Vs (1.5–1.6) and URRs (70%-73%) were comparable. No dialyzer was changed; 1 session was shortened 15 minutes because of circuit clot formation. Systemic argatroban clearance increased ∼20% during hemodialysis, without clinically significantly affecting ACTs. Upon argatroban discontinuation, ACTs and plasma argatroban decreased concurrently (elimination half-life, 35 ± 6 min). No thrombosis, bleeding, serious adverse events, or clinically significant changes in vital signs or routine laboratory measures occurred.ConclusionArgatroban, administered by each treatment regimen, provides safe, adequate anticoagulation to enable successful hemodialysis in ESRD patients. Argatroban dialytic clearance by high-flux membranes is clinically insignificant

The Effects of Hydration Status on Heart Rate Variability Following Supramaximal Intensity Exercise

Heart rate variability (HRV) is a non-invasive method used to monitor physiological stress via assessment of sympathetic and parasympathetic regulations and can indicate an individual’s recovery and readiness to exercise. Evidence suggests dehydration negatively impacts HRV; however, the influence of hydration status on HRV following supramaximal resistance exercise (RE) is unknown. PURPOSE: To investigate the effect of hydration status on HRV indices following supramaximal intensity RE. METHODS: 14 recreationally resistance-trained men (age, 21 ± 2 years; height, 176.25 ± 5.84 cm; weight, 81.31 ± 12.77 kg) participated in this study. In a randomized, counterbalanced order, participants performed a supramaximal intensity RE protocol in a euhydrated (EUH; urine specific gravity [USG] \u3c 1.020) and a dehydrated (DEH; USG \u3e 1.020) state, with conditions separated by 2 weeks. HRV indices (standard deviation of normal sinus beats [SDNN], root mean square of successive differences between normal heartbeats [RMSSD], high frequency power [HF], low frequency power [LF], LF:HF ratio, standard deviation of Poincaré plot perpendicular to [SD1] and along the line of identity [SD2]) were measured with participants lying in a supine position for 5 minutes in a dark room at baseline, immediately post-, 1hr-, 2hr-, and 3hr post-RE. Repeated measure analysis of variance was used to determine the effect of hydration status on HRV indices at each timepoint, with Bonferroni corrections for post-hoc analysis. RESULTS: RMSSD was significantly higher 1hr post-exercise in EUH (30.69 ± 7.09 ms) compared to DEH (16.31 ± 2.44 ms; p = 0.04). Similarly, HF power was significantly higher 1hr post-exercise in EUH (32.49 ± 4.12 %) compared to DEH (16.63 ± 2.71 %; p \u3c 0.01). In contrast, LF power was lower 1hr post-exercise in EUH (57.74 ± 3.62 %) compared to DEH (75.95 ± 3.42 %; p = 0.02), with LF:HF ratio significantly lower in EUH (2.36 ± 0.62) than DEH (6.21 ± 1.34; p = 0.01). SD1 was significantly greater 1hr post-exercise in EUH (21.74 ± 5.03 ms) than DEH (11.54 ± 1.73 ms; p = 0.04). No significant condition by time effects were observed for SDNN and SD2, or at remaining timepoints. CONCLUSION: These findings indicate that recovery and readiness to exercise are impaired 1hr following supramaximal intensity RE in a dehydrated state. However, impairments were ameliorated 2-3hrs proceeding the RE bout

The Effect of Dehydration and High-Volume Resistance Exercise on Intracellular and Local Muscular Fluid Shifts - A Pilot Study

Hypertonic hypovolemia (dehydration) could disrupt the balance between extracellular water (ECW) and intracellular water (ICW). Notably, high-volume resistance exercise (RE) accumulates metabolites resulting in acute muscle swelling (increased ICF). However, the impact of hypertonic hypovolemia state on ECW and ICW distribution after RE is not known. PURPOSE: To determine the effect of acute dehydration on fluid balance after RE. METHODS: 7 resistance-trained males completed two identical high-volume RE, separated by two weeks (bilateral leg press and knee extensions exercises [5 sets of 10 repetitions at 80% of 1 repetition maximum]) either in a euhydrated (EH; urine specific gravity [USG] \u3c 1.020) or dehydrated state (DH; USG ≥ 1.020; 24hr fluid fast). Total body water (TBW) and the ratio of ICW to ECW (ICW/ECW) were measured using bioelectrical impedance spectroscopy before (PRE), 1h, and 3h after RE. The rectus femoris thickness (RFT) was imaged using ultrasound at PRE, immediately (IP), 10m, 15m, and 30m after RE. Vastus lateralis samples were collected at PRE, 1h, and 3h and were immediately weighed (Wt) before and after heating at 80°C for 55 minutes. Repeated measures ANOVAs were used to identify the differences, and effect sizes were calculated if p values were trending. RESULTS: A significant (p \u3c 0.05) condition effect was observed for TBW, while a time effect was observed for ICW/ECW and RFT. For TBW, EH (1.00±0.06L) was greater than DH (0.95±0.05L). For ICW/ECW, PRE (1.00±0.00L) was lower than 1h (1.05±0.10L) and 3h (1.03±0.05L), while 1h was greater than PRE and 3h. For RFT, PRE (17.1±0.9mm) was less thick than IP (23.7±0.9mm), 10m (22.3±1.0mm), 15m (22.0±0.9mm), and 30m (21.5±1.0mm) while IP was thicker than all time points. Furthermore, EH (22.8±1.4mm) trended to have thicker RFT than DH (19.9±0.8mm; p=0.082; Cohen’s f = 0.85; large effect size). Additionally, a significant condition x time effect was observed for Wt. For Wt, EH (1.07±0.04mg) had a greater change in muscle weight than DH (1.01±0.06mg) at 1h. CONCLUSION: These results suggest that high volume RE can cause fluid shift from the extracellular to the intracellular compartment (i.e., increase ICW/ECF and RFT) regardless of the hydration status. Intriguingly, at the intramuscular level, it appears that the intramuscular water content after RE is less in dehydrated than euhydrated state (i.e., less changes in Wt)

The Ring Imaging Cherenkov detector (RICH) of the AMS experiment

The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and velocity of the charged cosmic particles. A RICH prototype consisting of 96 photomultiplier units, including a piece of the conical reflector, was built and its performance evaluated with ion beam data. Preliminary results of the in-beam tests performed with ion fragments resulting from collisions of a 158 GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported. The collected data included tests to the final front-end electronics and to different aerogel radiators. Cherenkov rings for a large range of charged nuclei and with reflected photons were observed. The data analysis confirms the design goals. Charge separation up to Fe and velocity resolution of the order of 0.1% for singly charged particles are obtained.Comment: 29th International Conference on Cosmic Rays (Pune, India

The AMS-RICH velocity and charge reconstruction

The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored. The algorithms developed to fulfill these requirements are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed.Comment: Contribution to the ICRC07, Merida, Mexico (2007); Presenter: F. Bara