26 research outputs found
Reconnection Outflows and Current Sheet Observed with Hinode/XRT in the 2008 April 9 "Cartwheel CME" Flare
Supra-arcade downflows (SADs) have been observed with Yohkoh/SXT (soft X-rays
(SXR)), TRACE (extreme ultra-violet (EUV)), SoHO/LASCO (white light),
SoHO/SUMER (EUV spectra), and Hinode/XRT (SXR). Characteristics such as low
emissivity and trajectories which slow as they reach the top of the arcade are
consistent with post-reconnection magnetic flux tubes retracting from a
reconnection site high in the corona until they reach a lower-energy magnetic
configuration. Viewed from a perpendicular angle, SADs should appear as
shrinking loops rather than downflowing voids. We present XRT observations of
supra-arcade downflowing loops (SADLs) following a coronal mass ejection (CME)
on 2008 April 9 and show that their speeds and decelerations are consistent
with those determined for SADs. We also present evidence for a possible current
sheet observed during this flare that extends between the flare arcade and the
CME. Additionally, we show a correlation between reconnection outflows observed
with XRT and outgoing flows observed with LASCO.Comment: 32 pages, 23 figures, Accepted for publication by the Astrophysical
Journal (Oct. 2010
Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study
Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk
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REGULATION OF SOX 4 AND SOX 11-MEDIATED GENE TRANSCRIPTION BY MIR-30-BASED RNAi
This projects goal was to use a plasmid previously cloned in our laboratory encoding miR30 to determine its effectiveness to knock down the expression of Sox4 and Sox11, two genes closely associated with tumor initiation and progress. Western blots and luciferase reporter assays showed that miR30-based shRNAs resulted in strong knock-down of Sox4 and Sox11 expression and a decrease in their induction of Sox-mediated gene transcription in 3T3 cells. Our results suggest that miR30-based shRNAs might be used as an effective cellular tool to investigate the role of Sox4/11 in tumorigenesis
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REGULATION OF SOX 4 AND SOX 11-MEDIATED GENE TRANSCRIPTION BY MIR-30-BASED RNAi
This projects goal was to use a plasmid previously cloned in our laboratory encoding miR30 to determine its effectiveness to knock down the expression of Sox4 and Sox11, two genes closely associated with tumor initiation and progress. Western blots and luciferase reporter assays showed that miR30-based shRNAs resulted in strong knock-down of Sox4 and Sox11 expression and a decrease in their induction of Sox-mediated gene transcription in 3T3 cells. Our results suggest that miR30-based shRNAs might be used as an effective cellular tool to investigate the role of Sox4/11 in tumorigenesis
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Management of the Rio Guaynabo Conservation Easement
This project, sponsored by the Conservation Trust of Puerto Rico, studied the Río Guaynabo Conservation Easement, a twenty-six acre parcel that was recently acquired by the Trust. The project group produced a separate management plan for the development of the property that includes a recommended trail map, detailed trail design strategies and techniques, and an interpretive program themed towards watershed education and conservation. The plan suggests ideas for a guided tour of the property that utilizes site specific information and interactive activities with the goal of educating the community about environmental responsibility and the importance of watershed conservation
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Modification of Pulsed Electric Field Conditions Results in Distinct Activation Profiles of Platelet-Rich Plasma
Background: Activated autologous platelet-rich plasma (PRP) used in therapeutic wound healing applications is poorly characterized and standardized. Using pulsed electric fields (PEF) to activate platelets may reduce variability and eliminate complications associated with the use of bovine thrombin. We previously reported that exposing PRP to sub-microsecond duration, high electric field (SMHEF) pulses generates a greater number of platelet-derived microparticles, increased expression of prothrombotic platelet surfaces, and differential release of growth factors compared to thrombin. Moreover, the platelet releasate produced by SMHEF pulses induced greater cell proliferation than plasma. Aims To determine whether sub-microsecond duration, low electric field (SMLEF) bipolar pulses results in differential activation of PRP compared to SMHEF, with respect to profiles of activation markers, growth factor release, and cell proliferation capacity. Methods: PRP activation by SMLEF bipolar pulses was compared to SMHEF pulses and bovine thrombin. PRP was prepared using the Harvest SmartPreP2 System from acid citrate dextrose anticoagulated healthy donor blood. PEF activation by either SMHEF or SMLEF pulses was performed using a standard electroporation cuvette preloaded with CaCl2 and a prototype instrument designed to take into account the electrical properties of PRP. Flow cytometry was used to assess platelet surface P-selectin expression, and annexin V binding. Platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), endothelial growth factor (EGF) and platelet factor 4 (PF4), and were measured by ELISA. The ability of supernatants to stimulate proliferation of human epithelial cells in culture was also evaluated. Controls included vehicle-treated, unactivated PRP and PRP with 10 mM CaCl2 activated with 1 U/mL bovine thrombin. Results: PRP activated with SMLEF bipolar pulses or thrombin had similar light scatter profiles, consistent with the presence of platelet-derived microparticles, platelets, and platelet aggregates whereas SMHEF pulses primarily resulted in platelet-derived microparticles. Microparticles and platelets in PRP activated with SMLEF bipolar pulses had significantly lower annexin V-positivity than those following SMHEF activation. In contrast, the % P-selectin positivity and surface P-selectin expression (MFI) for platelets and microparticles in SMLEF bipolar pulse activated PRP was significantly higher than that in SMHEF-activated PRP, but not significantly different from that produced by thrombin activation. Higher levels of EGF were observed following either SMLEF bipolar pulses or SMHEF pulses of PRP than after bovine thrombin activation while VEGF, PDGF, and PF4 levels were similar with all three activating conditions. Cell proliferation was significantly increased by releasates of both SMLEF bipolar pulse and SMHEF pulse activated PRP compared to plasma alone. Conclusions: PEF activation of PRP at bipolar low vs. monopolar high field strength results in differential platelet-derived microparticle production and activation of platelet surface procoagulant markers while inducing similar release of growth factors and similar capacity to induce cell proliferation. Stimulation of PRP with SMLEF bipolar pulses is gentler than SMHEF pulses, resulting in less platelet microparticle generation but with overall activation levels similar to that obtained with thrombin. These results suggest that PEF provides the means to alter, in a controlled fashion, PRP properties thereby enabling evaluation of their effects on wound healing and clinical outcomes
Flow cytometric analysis of platelets and platelet-derived microparticles (PDMP) in PRP following activation with SMLEF bipolar pulses, SMHEF monopolar pulses and thrombin.
<p>A) Representative forward- and side-light scatter profiles of (CD41/CD42b double positive) particles in activated and unactivated PRP samples. The oval indicates the location of the normal forward and side-light scatter distribution for intact platelets; CD41+/CD42b+ particles with lower forward and side light scatter are considered PDMP. B) PDMP as % of all CD41/CD42b double positive particles. Platelet count prior to stimulation was 1095.2 ± 192.9 x 10<sup>9</sup>/L (mean ± SD). C) Percentage of PDMP positive for surface phosphatidylserine as detected by annexin V binding; D) Percentage of platelets positive for surface phosphatidylserine as detected by annexin V binding; E) Percentage of all CD41/CD42b double positive particles positive for surface P-selectin. F) P-selectin mean fluorescence intensity (MFI) per particle. Upper and lower boundaries of boxes represent 25<sup>th</sup> and 75<sup>th</sup> %tile, whiskers represent 10<sup>th</sup> and 90<sup>th</sup> %tiles, line indicates median, n = 5. *p<0.05, **p<0.01, ***p<0.001.</p
Differential effects of SMLEF bipolar pulses, SMHEF pulses and thrombin on PRP activation, growth factor release, and cell proliferation.
<p>Differential effects of SMLEF bipolar pulses, SMHEF pulses and thrombin on PRP activation, growth factor release, and cell proliferation.</p