94 research outputs found
Adipocyte autophagy limits gut inflammation by controlling oxylipin and IL-10
Lipids play a major role in inflammatory diseases by altering inflammatory cell functions, either through their function as energy substrates or as lipid mediators such as oxylipins. Autophagy, a lysosomal degradation pathway that limits inflammation, is known to impact on lipid availability, however, whether this controls inflammation remains unexplored. We found that upon intestinal inflammation visceral adipocytes upregulate autophagy and that adipocyte-specific loss of the autophagy gene Atg7 exacerbates inflammation. While autophagy decreased lipolytic release of free fatty acids, loss of the major lipolytic enzyme Pnpla2/Atgl in adipocytes did not alter intestinal inflammation, ruling out free fatty acids as anti-inflammatory energy substrates. Instead, Atg7-deficient adipose tissues exhibited an oxylipin imbalance, driven through an NRF2-mediated upregulation of Ephx1. This shift reduced secretion of IL-10 from adipose tissues, which was dependent on the cytochrome P450-EPHX pathway, and lowered circulating levels of IL-10 to exacerbate intestinal inflammation. These results suggest an underappreciated fat-gut crosstalk through an autophagy-dependent regulation of anti-inflammatory oxylipins via the cytochrome P450-EPHX pathway, indicating a protective effect of adipose tissues for distant inflammation
Sensitivity of northeastern US surface ozone predictions to the representation of atmospheric chemistry in the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMMv1.0)
Chemical mechanisms describe how emissions of gases and particles evolve in
the atmosphere and are used within chemical transport models to evaluate
past, current, and future air quality. Thus, a chemical mechanism must
provide robust and accurate predictions of air pollutants if it is to be
considered for use by regulatory bodies. In this work, we provide an initial
evaluation of the Community Regional Atmospheric Chemistry Multiphase
Mechanism (CRACMMv1.0) by assessing CRACMMv1.0 predictions of surface ozone
(O3) across the northeastern US during the summer of 2018 within the
Community Multiscale Air Quality (CMAQ) modeling system. CRACMMv1.0 O3
predictions of hourly and maximum daily 8 h average (MDA8) ozone were
lower than those estimated by the Regional Atmospheric Chemistry Mechanism with aerosol module 6
(RACM2_ae6), which better matched surface network
observations in the northeastern US (RACM2_ae6 mean bias of
+4.2 ppb for all hours and +4.3 ppb for MDA8; CRACMMv1.0 mean bias of
+2.1 ppb for all hours and +2.7 ppb for MDA8). Box model calculations
combined with results from CMAQ emission reduction simulations indicated
a high sensitivity of O3 to compounds with biogenic sources. In addition,
these calculations indicated the differences between CRACMMv1.0 and
RACM2_ae6 O3 predictions were largely explained by
updates to the inorganic rate constants (reflecting the latest assessment
values) and by updates to the representation of monoterpene chemistry.
Updates to other reactive organic carbon systems between
RACM2_ae6 and CRACMMv1.0 also affected ozone predictions and
their sensitivity to emissions. Specifically, CRACMMv1.0 benzene, toluene,
and xylene chemistry led to efficient NOx cycling such that CRACMMv1.0 predicted controlling aromatics reduces ozone without rural O3
disbenefits. In contrast, semivolatile and intermediate-volatility alkanes
introduced in CRACMMv1.0 acted to suppress O3 formation across the
regional background through the sequestration of nitrogen oxides (NOx)
in organic nitrates. Overall, these analyses showed that the CRACMMv1.0 mechanism within the CMAQ model was able to reasonably simulate ozone
concentrations in the northeastern US during the summer of 2018 with similar
magnitude and diurnal variation as the current operational Carbon Bond
(CB6r3_ae7) mechanism and good model performance compared to recent
modeling studies in the literature.</p
Exploring Discipline Specific Disability Content: A Content Analysis Approach
(Book Chapter Under Review
Rapid pulse shaping with homodyne detection for measuring nonlinear optical signals
We have designed a common-mode interferometric acousto-optic pulse shaper that is capable of shaping individual pulses differently from a mode-locked laser. The design enables the measurement of weak nonlinear optical signals such as two-photon absorption and self-phase modulation at megahertz rates. The experimental apparatus incorporates homodyne detection as a means of resolving the phase of the detected signals. The fast data acquisition rate and the ability to perform measurements in scattering media make this experimental apparatus amenable to imaging applications analogous to measurements of two-photon fluorescence using a mode-locked laser
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