30 research outputs found
On the Location of the Gamma-ray Emission in the 2008 Outburst in the BL Lacertae Object AO 0235+164 through Observations across the Electromagnetic Spectrum
We present observations of a major outburst at centimeter, millimeter,
optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO
0235+164. We analyze the timing of multi-waveband variations in the flux and
linear polarization, as well as changes in Very Long Baseline Array (VLBA)
images at 7mm with 0.15 milliarcsecond resolution. The association of the
events at different wavebands is confirmed at high statistical significance by
probability arguments and Monte-Carlo simulations. A series of sharp peaks in
optical linear polarization, as well as a pronounced maximum in the 7 mm
polarization of a superluminal jet knot, indicate rapid fluctuations in the
degree of ordering of the magnetic field. These results lead us to conclude
that the outburst occurred in the jet both in the quasi-stationary "core" and
in the superluminal knot, both parsecs downstream of the supermassive black
hole. We interpret the outburst as a consequence of the propagation of a
disturbance, elongated along the line of sight by light-travel time delays,
that passes through a standing recollimation shock in the core and propagates
down the jet to create the superluminal knot. The multi-wavelength light curves
vary together on long time-scales (months/years), but the correspondence is
poorer on shorter time-scales. This, as well as the variability of the
polarization and the dual location of the outburst, agrees with the
expectations of a multi-zone emission model in which turbulence plays a major
role in modulating the synchrotron and inverse Compton fluxes.Comment: Accepted for Publication in the Astrophysical Journal Letters. 7
pages (including 5 figures). Minor corrections with regard to previous
version, as proposed by the refere
A Daphnane Diterpenoid Isolated from Wikstroemia polyantha Induces an Inflammatory Response and Modulates miRNA Activity
MicroRNAs (miRNAs) are endogenously expressed single-stranded ∼21–23 nucleotide RNAs that inhibit gene expression post-transcriptionally by binding imperfectly to elements usually within the 3′untranslated region (3′UTR) of mRNAs. Small interfering RNAs (siRNAs) mediate site-specific cleavage by binding with perfect complementarity to RNA. Here, a cell-based miRNA reporter system was developed to screen for compounds from marine and plant extracts that inhibit miRNA or siRNA activity. The daphnane diterpenoid genkwanine M (GENK) isolated from the plant Wikstroemia polyantha induces an early inflammatory response and can moderately inhibit miR-122 activity in the liver Huh-7 cell line. GENK does not alter miR-122 levels nor does it directly inhibit siRNA activity in an in vitro cleavage assay. Finally, we demonstrate that GENK can inhibit HCV infection in Huh-7 cells. In summary, the development of the cell-based miRNA sensor system should prove useful in identifying compounds that affect miRNA/siRNA activity
Biology, Ecology, and Evolving Management of Helicoverpa zea (Lepidoptera: Noctuidae) in Sweet Corn in the United States
The corn earworm, Helicoverpa zea (Boddie), is a polyphagous pest found throughout the United States, where it attacks many field and vegetable crops. Although H. zea has long been a traditional pest of sweet corn, its importance to this crop has increased dramatically over the past two decades. In this review, we summarize information critical for current and future management of H. zea in sweet corn production in the United States. First, we discuss the pest status of H. zea and its life history, including migration, infestation and larval development, diapause, overwintering, and abiotic factors that affect its biology. Next we describe monitoring methods, crop protection decision-making processes, chemical control options, and the use of genetic technologies for control of H. zea. Alternative H. zea management options including biological control, cultural controls, host plant resistance, and pheromone disruption are also reviewed. The role of climate change and its effects on H. zea and its ecology are discussed, as well as the recent invasion of its relative, Helicoverpa armigera (Hübner), which is a major pest of corn in other parts of the world. To conclude, we suggest future research opportunities for H. zea and H. armigera management in sweet corn
Comparative effectiveness of coronary artery bypass grafting versus percutaneous coronary intervention in a real-world Surgical Treatment for Ischemic Heart Failure trial population.
OBJECTIVE: There are no prospective randomized trial data to guide decisions on optimal revascularization strategies for patients with multivessel coronary artery disease and reduced ejection fraction. In this analysis, we describe the comparative effectiveness of coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) in this patient population.
METHODS: A multicenter, retrospective analysis of all CABG (n = 18,292) and PCIs (n = 55,438) performed from 2004 to 2014 among 7 medical centers reporting to the Northern New England Cardiovascular Disease Study Group. After applying inclusion and exclusion criteria from the Surgical Treatment for Ischemic Heart Failure trial, there were 955 CABG and 718 PCI patients with an ejection fraction ≤ 35% and 2- or 3-vessel disease. Inverse probability weighting was used for risk adjustment. The primary end point was all-cause mortality. Secondary end points included rates of 30-day mortality, stroke, acute kidney injury, and incidence of repeat revascularization.
RESULTS: The median duration of follow-up was 4.3 years (range, 1.59-6.71 years). CABG was associated with improved long-term survival compared with PCI after risk adjustment (hazard ratio, 0.59; 95% confidence interval, 0.50-0.71; P \u3c .01). Although CABG and PCI had similar 30-day mortality rates (P = .14), CABG was associated with a higher frequency of stroke (P \u3c .001) and acute kidney injury (P \u3c .001), whereas PCI was associated with a higher incidence of repeat revascularization (P \u3c .001).
CONCLUSIONS: Among patients with reduced ejection fraction and multivessel disease, CABG was associated with improved long-term survival compared with PCI. CABG should be strongly considered in patients with ischemic cardiomyopathy and multivessel coronary disease
Intensity of Glycemic Control Affects Long-Term Survival After Coronary Artery Bypass Graft Surgery.
BACKGROUND: A patient\u27s hemoglobin (Hb) A
METHODS: From a regional registry of consecutive cases, we identified 6,415 patients undergoing on-pump isolated CABG from 2008 to 2015 with documented preoperative HbA
RESULTS: The study included 3,740 patients (58%) not diagnosed as having diabetes and 2,674 with diabetes. Prediabetes (HbA
CONCLUSIONS: Preadmission glycemic control, as assessed by Hb
Determination of Structural Building Blocks in Heavy Petroleum Systems by Collision-Induced Dissociation Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
Collision-induced dissociation Fourier Transform ion
cyclotron
resonance mass spectrometry (CID-FTICR MS) was developed to determine
structural building blocks in heavy petroleum systems. Model compounds
with both single core and multicore configurations were synthesized
to study the fragmentation pattern and response factors in the CID
reactions. Dealkylation is found to be the most prevalent reaction
pathway in the CID. Single core molecules exhibit primarily molecular
weight reduction with no change in the total unsaturation of the molecule
(or <i>Z</i>-number as in chemical formula C<i><sub>c</sub></i>H<sub>2<i>c</i>+<i>Z</i></sub>N<sub><i>n</i></sub>S<i><sub>s</sub></i>O<sub><i>o</i></sub>VNi). On the other hand, molecules containing
more than one aromatic core will decompose into the constituting single
cores and consequently exhibit both molecular weight reduction and
change in <i>Z</i>-numbers. Biaryl linkage, C<sub>1</sub> linkage, and aromatic sulfide linkage cannot be broken down by CID
with lab collision energy up to 50 eV while C<sub>2</sub>+ alkyl linkages
can be easily broken. Naphthenic ring-openings were observed in CID,
leading to formation of olefinic structures. Heavy petroleum systems,
such as vacuum resid (VR) fractions, were characterized by the CID
technology. Both single-core and multicore structures were found in
VR. The latter is more prevalent in higher aromatic ring classes
Variability in surgeons\u27 perioperative practices may influence the incidence of low-output failure after coronary artery bypass grafting surgery.
BACKGROUND: Postoperative low-output failure (LOF) is an important contributor to morbidity and mortality after coronary artery bypass grafting surgery. We sought to understand which pre- and intra-operative factors contribute to postoperative LOF and to what degree the surgeon may influence rates of LOF.
METHODS AND RESULTS: We identified 11 838 patients undergoing nonemergent, isolated coronary artery bypass grafting surgery using cardiopulmonary bypass by 32 surgeons at 8 centers in northern New England from 2001 to 2009. Our cohort included patients with preoperative ejection fractions \u3e40%. Patients with preoperative intraaortic balloon pumps were excluded. LOF was defined as the need for ≥2 inotropes at 48 hours, an intra- or post-operative intraaortic balloon pumps, or return to cardiopulmonary bypass (for hemodynamic reasons). Case volume varied across the 32 surgeons (limits, 80-766; median, 344). The overall rate of LOF was 4.3% (return to cardiopulmonary bypass, 2.6%; intraaortic balloon pumps, 1.0%; inotrope usage, 0.8%; combination, 1.0%). The predicted risk of LOF did not differ across surgeons, P=0.79, and the observed rates varied from 1.1% to 10.2%, P
CONCLUSIONS: Rates of LOF significantly varied across surgeons and could not be explained solely by patient case mix, suggesting that variability in perioperative practices influences risk of LOF