1,826 research outputs found
Elevated PAI-1 is associated with poor clinical outcomes in pediatric patients with acute lung injury.
PurposeDeposition of fibrin in the alveolar space is a hallmark of acute lung injury (ALI). Plasminogen activator inhibitor-1 (PAI-1) is an antifibrinolytic agent that is activated during inflammation. Increased plasma and pulmonary edema fluid levels of PAI-1 are associated with increased mortality in adults with ALI. This relationship has not been examined in children. The objective of this study was to test whether increased plasma PAI-1 levels are associated with worse clinical outcomes in pediatric patients with ALI.Design/methodsWe measured plasma PAI-1 levels on the first day of ALI among 94 pediatric patients enrolled in two separate prospective, multicenter investigations and followed them for clinical outcomes. All patients met American European Consensus Conference criteria for ALI.ResultsA total of 94 patients were included. The median age was 3.2 years (range 16 days-18 years), the PaO(2)/F(i)O(2) was 141 +/- 72 (mean +/- SD), and overall mortality was 14/94 (15%). PAI-1 levels were significantly higher in nonsurvivors compared to survivors (P < 0.01). The adjusted odds of mortality doubled for every log increase in the level of plasma PAI-1 after adjustment for age and severity of illness.ConclusionsHigher PAI-1 levels are associated with increased mortality and fewer ventilator-free days among pediatric patients with ALI. These findings suggest that impaired fibrinolysis may play a role in the pathogenesis of ALI in pediatric patients and suggest that PAI-1 may serve as a useful biomarker of prognosis in patients with ALI
Oxidation and protection of fiberglass-epoxy composite masts for photovoltaic arrays in the low Earth orbital environment
Fiberglass-epoxy composites are considered for use as structural members for the mast of the space station solar array panel. The low Earth orbital environment in which space station is to operate is composed mainly of atomic oxygen, which has been shown to cause erosion of many organic materials and some metals. Ground based testing in a plasma asher was performed to determine the extent of degradation of fiberglass-epoxy composites when exposed to a simulated atomic oxygen environment. During exposure, the epoxy at the surface of the composite was oxidized, exposing individual glass fibers which could easily be removed. Several methods of protecting the composite were evaluated in an atomic oxygen environment and with thermal cycling and flexing. The protection techniques evaluated to date include an aluminum braid covering, an indium-tin eutectic and a silicone based paint. The open aluminum braid offered little protection while the CV-1144 coating offered some initial protection against atomic oxygen, but appears to develop cracks which accelerate degradation when flexed. Coatings such as the In-Sn eutectic may provide adequate protection by containing the glass fibers even though mass loss still occurs
High temperature radiator materials for applications in the low Earth orbital environment
Radiators must be constructed of materials which have high emittance in order to efficiently radiate heat from high temperature space power systems. In addition, if these radiators are to be used for applications in the low Earth orbital environment, they must not be detrimentally affected by exposure to atomic oxygen. Four materials selected as candidate radiator materials (304 stainless steel, copper, titanium-6% aluminum-4% vanadium (Ti-6%Al-4%V), and niobium-1% zirconium (Nb-1%Zr)) were surface modified by acid etching, heat treating, abrading, sputter texturing, electrochemical etching, and combinations of the above in order to improve their emittance. Combination treatment techniques with heat treating as the second treatment provided about a factor of two improvement in emittance for 304 stainless steel, Ti-6%Al-4%V, and Nb-1%Zr. A factor of three improvement in emittance occurred for discharge chamber sputter textured copper. Exposure to atomic oxygen in an RF plasma asher did not significantly change the emittance of those samples that had been heat treated as part of their texturing process. An evaluation of oxygen penetration is needed to understand how oxidation affects the mechanical properties of these materials when heat treated
Implementing Bluebeam Software in Architectural Engineering Design Courses
A critical aspect of structural engineering education is helping students develop effective electronic graphical communication skills to convey their design solutions. Many undergraduate civil and architectural engineering programs address this at the document creation stage by teaching Autodesk AutoCAD or Revit to create 2-D or 3-D structural design files. However, students tend to have limited exposure to commercial software for document management and markup that allows for coordination between the engineer, architect, and contractor teams. Bluebeam Revu is one such software that has emerged as an industry standard for annotation and markup of engineering design documents.
Previous educational studies on the use of Bluebeam have been in construction management courses where students practice plan reading. The main motivation for instructors to incorporate this software in their classes is to expose students to technology they will encounter as practitioners, especially significant since contractors view these drawings as a legal description of their scope of work. Therefore, the production and interpretation of the documents requires that they exhibit a high level of accuracy, specificity, and clarity.
This paper focuses on the use of Bluebeam markup and grading in architectural engineering courses to enable communication between faculty and students during the iterative structural design process. The paper provides sample student hand calculations, sketches, and CAD structural drawings with Bluebeam markups provided by practitioner faculty. This markup describes and models how the student might implement necessary design changes.
Feedback collected via interviews of course graders, surveys of students, and faculty co-authors is included and illustrates that the use of Bluebeam markup in architectural engineering courses provides a meaningful and efficient review during the development of a structural design solution. The goal of this paper is to show instructors how to integrate Bluebeam into a course, beyond plan reading activities. Faculty will thus be equipped to educate students on a software commonly used in structural design firms for quality assurance/quality control (QA/QC) and communication between the design and construction disciplines
Nuclear Magnetic Resonance Implemented Synthetic Indole and Indazole Cannabinoid Detection, Identification, and Quantification
The present invention provides a method for detecting synthetic indole and indazole cannabinoids in a sample known or suspected to contain a synthetic indole or indazole cannabinoid. A deuterated solvent is added to the solid sample, creating a suspension. The suspension is mixed to release the cannabinoid from the solid sample. The suspension is subject to a NMR spectroscopy process to produce a sample NMR spectrum
Functional neuroimaging of post-mortem tissue: lithium-pilocarpine seized rats express reduced brain mass and proportional reductions of left ventral cerebral theta spectral power
AbstractStructural imaging tools can be used to identify neuropathology in post-mortem tissue whereas functional imaging tools including quantitative electroencephalography (QEEG) are thought to be restricted for use in living subjects. We are not aware of any study which has used electrophysiological methods decades after death to infer pathology. We therefore attempted to discriminate between chemically preserved brains which had incurred electrical seizures and those that did not using functional imaging. Our data indicate that modified QEEG technology involving needle electrodes embedded within chemically fixed neural tissue can be used to discriminate pathology. Forty (n = 40) rat brains preserved in ethanol-formalin-acetic acid (EFA) were probed by needle electrodes inserted into the dorsal and ventral components of the left and right cerebral hemispheres. Raw microvolt potentials were converted to spectral power densities within classical electroencephalographic frequency bands (1.5 Hz to 40 Hz). Brain mass differences were shown to scale with left hemispheric ventral theta-band spectral power densities in lithium-pilocarpine seized rats. This relationship was not observed in non-seized rats. A conspicuous absence of pathological indicators within dorsal regions as inferred by microvolt fluctuations was expected given the known localization of post-ictal damage in lithium-pilocarpine seized rats. Together, the data demonstrate that post-mortem neuroimaging is both possible and potentially useful as a means to identify neuropathology without structural imaging techniques or dissection
Effects of Osmotic Stress on DNA and Cell Viability in a Desiccation-Sensitive Cell Line
Kc167 is a widely used Drosophila cell line, known to be sensitive to the extreme water loss caused by desiccation. In order to characterize the effects of this desiccation-sensitivity on DNA and cell viability, a series of osmotic stressors of differing concentrations were introduced to the cell line. These cells were then imaged via the Cytation1 cell imaging machine using fluorescence microscopy. Specifically, cells were stained using the DAPI staining solution, a blue fluorescent DNA stain that binds strongly to A-T rich regions within the DNA, forming a fluorescent complex. As DAPI more readily enters the membrane and thereby stains dead cells, instances of apoptosis caused by osmotic stress on cells can be characterized by increasing intensity of fluorescence. Both sucrose and sodium chloride were used to simulate the water loss relevant to that of desiccation. This was done in concentrations of 100mM, 250mM, and 500mM for both sucrose and sodium chloride
Developing Objective Tests and Repair Guidelines for Hog Facility Trusses
• Predicting naturally ventilated hog barns life expectancy
• Increase useful life of facilities and provide options to growers
• Barn collapses and safety of personnel, livestock, facilities, and other assets
• Provide cost breakdown of complete replacement vs. truss repair option
Biological markers of lung injury before and after the institution of positive pressure ventilation in patients with acute lung injury
BACKGROUND: Several biological markers of lung injury are predictors of morbidity and mortality in patients with acute lung injury (ALI). The low tidal volume lung-protective ventilation strategy is associated with a significant decrease in plasma biomarker levels compared to the high tidal volume ventilation strategy. The primary objective of this study was to test whether the institution of lung-protective positive pressure ventilation in spontaneously ventilating patients with ALI exacerbates pre-existing lung injury by using measurements of biomarkers of lung injury before and after intubation. MATERIALS AND METHODS: A prospective observational cohort study was conducted in the intensive care unit of a tertiary care university hospital. Twenty-five intubated, mechanically ventilated patients with ALI were enrolled. Physiologic data and serum samples were collected within 6 hours before intubation and at two different time points within the first 24 hours after intubation to measure the concentration of interleukin (IL)-6, IL-8, intercellular adhesion molecule 1 (ICAM-1), and von Willebrand factor (vWF). The differences in biomarker levels before and after intubation were analysed using repeated measures analysis of variance and a paired t test with correction for multiple comparisons. RESULTS: Before endotracheal intubation, all of the biological markers (IL-8, IL-6, ICAM-1, and vWF) were elevated in the spontaneously breathing patients with ALI. After intubation and the institution of positive pressure ventilation (tidal volume 7 to 8 ml/kg per ideal body weight), none of the biological markers was significantly increased at either an early (3 ± 2 hours) or later (21 ± 5 hours) time point. However, the levels of IL-8 were significantly decreased at the later time point (21 ± 5 hours) after intubation. During the 24-hour period after intubation, the PaO(2)/FiO(2 )(partial pressure of arterial oxygen/fraction of the inspired oxygen) ratio significantly increased and the plateau airway pressure significantly decreased. CONCLUSION: Levels of IL-8, IL-6, vWF, and ICAM-1 are elevated in spontaneously ventilating patients with ALI prior to endotracheal intubation. The institution of a lung-protective ventilation strategy with positive pressure ventilation does not further increase the levels of biological markers of lung injury. The results suggest that the institution of a lung-protective positive pressure ventilation strategy does not worsen the pre-existing lung injury in most patients with ALI
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