Local vasodilation in response to hypoxia is a fundamental physiologic response ensuring oxygen delivery to tissues under metabolic stress. Recent studies identify a role for the red blood cell ...(RBC), with hemoglobin the hypoxic sensor. Herein, we investigate the mechanisms regulating this process and explore the relative roles of adenosine triphosphate, S-nitrosohemoglobin, and nitrite as effectors. We provide evidence that hypoxic RBCs mediate vasodilation by reducing nitrite to nitric oxide (NO) and ATP release. NO dependence for nitrite-mediated vasodilation was evidenced by NO gas formation, stimulation of cGMP production, and inhibition of mitochondrial respiration in a process sensitive to the NO scavenger C-PTIO. The nitrite reductase activity of hemoglobin is modulated by heme deoxygenation and heme redox potential, with maximal activity observed at 50% hemoglobin oxygenation (P50). Concomitantly, vasodilation is initiated at the P50, suggesting that oxygen sensing by hemoglobin is mechanistically linked to nitrite reduction and stimulation of vasodilation. Mutation of the conserved β93cys residue decreases the heme redox potential (ie, decreases E1/2), an effect that increases nitrite reductase activity and vasodilation at any given hemoglobin saturation. These data support a function for RBC hemoglobin as an allosterically and redox-regulated nitrite reductase whose “enzyme activity” couples hypoxia to increased NO-dependent blood flow.
Nitrogen dioxide (NO2) is a short-lived atmospheric pollutant that serves as an air quality indicator and is itself a health concern. The Airborne Compact Atmospheric Mapper (ACAM) was flown on board ...the NASA UC-12 aircraft during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality Maryland field campaign in July 2011. The instrument collected hyperspectral remote sensing measurements in the 304-910 nm range, allowing daytime observations of several tropospheric pollutants, including nitrogen dioxide (NO2), at an unprecedented spatial resolution of 1.5 × 1.1 sq. km. Retrievals of slant column abundance are based on the differential optical absorption spectroscopy method. For the air mass factor computations needed to convert these retrievals to vertical column abundance, we include high-resolution information for the surface reflectivity by using bidirectional reflectance distribution function data from the Moderate Resolution Imaging Spectroradiometer. We use high-resolution simulated vertical distributions of NO2 from the Community Multiscale Air Quality and Global Modeling Initiative models to account for the temporal variation in atmospheric NO2 to retrieve middle and lower tropospheric NO2 columns (NO2 below the aircraft). We compare NO2 derived from ACAM measurements with in situ observations from NASA's P-3B research aircraft, total column observations from the ground-based Pandora spectrometers, and tropospheric column observations from the space-based Ozone Monitoring Instrument. The high-resolution ACAM measurements not only give new insights into our understanding of atmospheric composition and chemistry through observation of subsampling variability in typical satellite and model resolutions, but they also provide opportunities for testing algorithm improvements for forthcoming geostationary air quality missions.
We report high-precision measurements of the longitudinal double-spin asymmetry, ALL, for midrapidity inclusive jet and dijet production in polarized p p collisions at a center-of-mass energy of √ s ...= 200 GeV . The new inclusive jet data are sensitive to the gluon helicity distribution, Δg (x, Q2), for gluon momentum fractions in the range from x ≃ 0.05 to x ≃ 0.5, while the new dijet data provide further constraints on the x dependence of Δ g (x , Q2). The results are in good agreement with previous measurements at √ s = 200 GeV and with recent theoretical evaluations of prior world data. Our new results have better precision and thus strengthen the evidence that Δg(x,Q2) is positive for x > 0.05.
This study reports measurements of size-resolved aerosol
composition at a site in Incheon along with other aerosol characteristics
for contrast between Incheon (coastal) and Seoul (inland), South ...Korea,
during a transboundary pollution event during the early part of an intensive
sampling period between 4 and 11 March 2019. Anthropogenic emissions were
dominant in the boundary layer over the study region between 4 and 6 March,
with much smaller contributions from dust, smoke, and sea salt. The
meteorology of this period (shallow boundary layer, enhanced humidity, and
low temperature) promoted local heterogeneous formation of secondary
inorganic and organic species, including high nitrate (NO3-)
relative to sulfate (SO42-). Seoul exhibited higher PM2.5
levels than Incheon, likely due to local emissions. The following findings
point to secondary aerosol formation and growth sensitivity to water vapor
during this pollution event: (i) significant concentrations of individual
inorganic and organic acids in the supermicrometer range relative to their
full size range (∼40 %) at higher humidity; (ii) high
correlation (r=0.95) between oxalate and SO42-, a marker of
secondary aqueous production of oxalate; (iii) increased sulfur and nitrogen
oxidation ratios as a function of humidity; and (iv) matching composition
apportionment (for soluble ions) between the PM1 and PM2.5−1 size
fractions. The last finding confirms that PM1 aerosol composition
measurements fully capture PM2.5 composition apportionment (for soluble
ions) during haze events and may therefore be reliably applied in modeling
studies of such events over the full PM2.5 size range. However, the
differences evident in the periods following the haze event imply that under
other atmospheric conditions PM1 composition measurements will not
fully reflect the apportionment of PM2.5 aerosols. The study period was
marked by relatively low temperatures that made NO3- the most
abundant species detected, pointing to the sensitivity of PM2.5 levels
and composition as a function of season during such transboundary events.
For instance, other such events in previous studies exhibited more
comparable levels between SO42- and NO3- coincident with
higher temperatures than the current study. This dataset can contribute to
future evaluation of model PM2.5 composition to better support
regulatory efforts to control PM2.5 precursors.
We report the first measurements of transverse single-spin asymmetries for inclusive jet and jet+π± production at midrapidity from transversely polarized proton-proton collisions at s=500 GeV. The ...data were collected in 2011 with the STAR detector sampled from 23 pb−1 integrated luminosity with an average beam polarization of 53%. Asymmetries are reported for jets with transverse momenta 6<pT<55 GeV/c and pseudorapidity |η|<1. Presented are measurements of the inclusive-jet azimuthal transverse single-spin asymmetry, sensitive to twist-3 initial-state quark-gluon correlators; the Collins asymmetry, sensitive to quark transversity coupled to the polarized Collins fragmentation function; and the first measurement of the “Collins-like” asymmetry, sensitive to linearly polarized gluons. Within the present statistical precision, inclusive-jet and Collins-like asymmetries are small, with the latter allowing the first experimental constraints on gluon linear polarization in a polarized proton. At higher values of jet transverse momenta, we observe the first nonzero Collins asymmetries in polarized-proton collisions, with a statistical significance of greater than 5σ. The results span a range of x similar to results from semi-inclusive deep-inelastic scattering but at much higher Q2. The Collins results enable tests of universality and factorization breaking in the transverse momentum-dependent formulation of perturbative quantum chromodynamics.
p32 also known as HABP1 (hyaluronan-binding protein 1), gC1qR (receptor for globular head domains complement 1q) or C1qbp (complement 1q-binding protein) has been shown previously to have both ...mitochondrial and non-mitochondrial localization and functions. In the present study, we show for the first time that endogenous p32 protein is a mitochondrial protein in HeLa cells under control and stress conditions. In defining the impact of altering p32 levels in these cells, we demonstrate that the overexpression of p32 increased mitochondrial fibrils. Conversely, siRNA-mediated p32 knockdown enhanced mitochondrial fragmentation accompanied by a loss of detectable levels of the mitochondrial fusion mediator proteins Mfn (mitofusin) 1 and Mfn2. More detailed ultrastructure analysis by transmission electron microscopy revealed aberrant mitochondrial structures with less and/or fragmented cristae and reduced mitochondrial matrix density as well as more punctate ER (endoplasmic reticulum) with noticeable dissociation of their ribosomes. The analysis of mitochondrial bioenergetics showed significantly reduced capacities in basal respiration and oxidative ATP turnover following p32 depletion. Furthermore, siRNA-mediated p32 knockdown resulted in differential stress-dependent effects on cell death, with enhanced cell death observed in the presence of hyperosmotic stress or cisplatin treatment, but decreased cell death in the presence of arsenite. Taken together, our studies highlight the critical contributions of the p32 protein to the morphology of mitochondria and ER under normal cellular conditions, as well as important roles of the p32 protein in cellular metabolism and various stress responses.
Background
Besides physical activity as a target for dementia prevention, sedentary behaviour is hypothesized to be a potential target in its own right. The rising number of persons with dementia and ...lack of any effective treatment highlight the urgency to better understand these modifiable risk factors. Therefore, we aimed to investigate whether higher levels of sedentary behaviour are associated with reduced global cognitive functioning and slower cognitive decline in older persons without dementia.
Methods
We used five population cohorts from Greece, Australia, USA, Japan, and Singapore (HELIAD, PATH, SALSA, SGS, and SLAS2) from the Cohort Studies of Memory in an International Consortium. In a coordinated analysis, we assessed the relationship between sedentary behaviour and global cognitive function with the use of linear mixed growth model analysis (mean follow-up range of 2.0–8.1 years).
Results
Baseline datasets combined 10,450 older adults without dementia with a mean age range between cohorts of 66.7–75.1 years. After adjusting for multiple covariates, no cross-sectional association between sedentary behaviour and cognition was found in four studies. One association was detected where more sedentary behaviour was cross-sectionally linked to higher cognition levels (SLAS2,
B
= 0.118 (0.075; 0.160),
P
< 0.001). Longitudinally, there were no associations between baseline sedentary behaviour and cognitive decline (
P
> 0.05).
Conclusions
Overall, these results do not suggest an association between total sedentary time and lower global cognition in older persons without dementia at baseline or over time. We hypothesize that specific types of sedentary behaviour may differentially influence cognition which should be investigated further. For now, it is, however, too early to establish undifferentiated sedentary time as a potential effective target for minimizing cognitive decline in older adults without dementia.
The NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission was conducted in February-April 2001 over the NW Pacific (1) to characterize the Asian chemical outflow and ...relate it quantitatively to its sources and (2) to determine its chemical evolution. It used two aircraft, a DC-8 and a P-3B, operating out of Hong Kong and Yokota Air Force Base (near Tokyo), with secondary sites in Hawaii, Wake Island, Guam, Okinawa, and Midway. The aircraft carried instrumentation for measurements of long-lived greenhouse gases, ozone and its precursors, aerosols and their precursors, related species, and chemical tracers. Five chemical transport models (CTMs) were used for chemical forecasting. Customized bottom-up emission inventories for East Asia were generated prior to the mission to support chemical forecasting and to serve as a priori for evaluation with the aircraft data. Validation flights were conducted for the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument and revealed little bias (6 plus or minus 2%) in the MOPITT measurements of CO columns. A major event of transpacific Asian pollution was characterized through combined analysis of TRACE-P and MOPITT data. The TRACE-P observations showed that cold fronts sweeping across East Asia and the associated warm conveyor belts (WCBs) are the dominant pathway for Asian outflow to the Pacific in spring. The WCBs lift both anthropogenic and biomass burning (SE Asia) effluents to the free troposphere, resulting in complex chemical signatures. The TRACE-P data are in general consistent with a priori emission inventories, lending confidence in our ability to quantify Asian emissions from socioeconomic data and emission factors. However, the residential combustion source in rural China was found to be much larger than the a priori, and there were also unexplained chemical enhancements (HCN, CH3Cl, OCS, alkylnitrates) in Chinese urban plumes. The Asian source of CCl4 was found to be much higher than government estimates. Measurements of HCN and CH3CN indicated a dominant biomass burning source and ocean sink for both gases. Large fractions of sulfate and nitrate were found to be present in dust aerosols. Photochemical activity in the Asian outflow was strongly reduced by aerosol attenuation of UV radiation, with major implications for the concentrations of HOx, radicals. New particle formation, apparently from ternary nucleation involving NH3, was observed in Chinese urban plumes.
Robotic versus laparoscopic colectomy RAWLINGS, A. L; WOODLAND, J. H; VEGUNTA, R. K ...
Surgical endoscopy,
10/2007, Letnik:
21, Številka:
10
Journal Article
Recenzirano
This study compared the experience and cost of the DaVinci Robotic system and laparoscopy for colon resections.
For this study, 30 consecutive robotic and 27 consecutive laparoscopic colectomies were ...divided into right and sigmoid colectomies for analysis. Comparisons included indications for surgery, gender, age, body mass index (BMI), estimated blood loss (EBL), length of operation, length of hospital stay (LOS), complications, operating room (OR) cost, OR personnel cost, OR supply cost, OR time cost, and total hospital cost.
The comparison groups were similar in indications for surgery, gender, age, BMI, EBL, and LOS. The right colectomies included 17 robotic and 15 laparoscopic procedures. An intracorporeal anastomosis was performed in the robotic cases, and an extracorporeal anastomosis was performed in the laparoscopic cases. The total case time was 218.9 min for the robotic and 169.2 min for the laparoscopic procedures (p = 0.002). The total hospital cost was $9,255 for the robotic and $8,073 for the laparoscopic procedures (p = 0.430). The total OR cost was $5,823 for the robotic and $4,339 for the laparoscopic procedures (p < 0.000). The sigmoid colectomies included 13 robotic and 12 laparoscopic procedures. The robotic and laparoscopic cases were managed in similar sequence. The total case time was 225.2 min for the robotic and 199.4 min for the laparoscopic procedures (p = 0.128). The total hospital cost was $12,335 for the robotic and $10,697 for the laparoscopic procedures (p = 0.735). The total OR cost was $6,059 for the robotic and $4,974 for the laparoscopic procedures (p = 0.068). The complications in the robotic groups were more numerous, but were not attributable to equipment.
The comparison groups were similar. The robotic cases were significantly longer for right colectomies because of the intracorporeal anastomosis instead of the extracorporeal anastomosis performed in the laparoscopy cases. Every cost category was higher for the robotic cases. The right colectomies showed significant increases in total OR cost, OR personnel cost, OR supply cost, and OR time cost. The sigmoid colectomies had significant increases in OR personnel cost and OR supply cost. The total hospital cost was higher for the robotic groups, but the difference was not statistically significant.
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