189 research outputs found

    A Sustainable Remediation Approach for Complete Destruction of Chloroethanes in Groundwater

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    An up-flow column study was operated in a greenhouse composed of a sand/peat mixed media to investigate the effectiveness of an aerobic zone on the disappearances of chloroethane. The oxygen was supplied by mean of porous Silastic tubing under pressure with a breathing air gas cylinder. Chloroethane was generated via reductive dechlorination of 1,1,1-trichloroethane (TCA) and 1,1-dichloroethane (DCA) in anaerobic bioreactors (ABRs). The columns study was conducted with two duplicate reactors (operated in parallel) that underwent separate perturbations of breathing air introduction. Aqueous samples were collected in 160 mL microcosm bottles and analyzed on a GC equipped with a Flame Ionization Detector. A statistical analysis of the data was conducted using a 2-tailed Student’s T-test. Results showed that decreases in aqueous chloroethane were greater during periods of aeration in both reactors, with approximately 41% changes in chloroethane concentration from the influent to the final port (Port 3), during periods of aeration. An analysis of changes that ensued from implementation of a full-scale anaerobic bioreactor system (ABR) to replace a physical/chemical treatment scheme was conducted using site specific data. Carbon dioxide emissions and energy requirements associated with operation of the site with each treatment scheme were compared. Specifically, source of energy to run the site, transportation of generated sludge, and utilization of chemicals (sodium hydroxide and sulfuric acid) were studied. Production of grid-based energy for site operation was eradicated through implementation of a solar-system. Generated sludge production decreased, resulting in a 92% decrease in implied inputs to the Petroleum Refineries sector. Carbon dioxide emissions and energy inputs to commercial production of sodium hydroxide and sulfuric acid also decreased by 92%

    Abdominal Compartment Syndrome: pathophysiology and definitions

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    "Intra-abdominal hypertension", the presence of elevated intra-abdominal pressure, and "abdominal compartment syndrome", the development of pressure-induced organ-dysfunction and failure, have been increasingly recognized over the past decade as causes of significant morbidity and mortality among critically ill surgical and medical patients. Elevated intra-abdominal pressure can cause significant impairment of cardiac, pulmonary, renal, gastrointestinal, hepatic, and central nervous system function. The significant prognostic value of elevated intra-abdominal pressure has prompted many intensive care units to adopt measurement of this physiologic parameter as a routine vital sign in patients at risk. A thorough understanding of the pathophysiologic implications of elevated intra-abdominal pressure is fundamental to 1) recognizing the presence of intra-abdominal hypertension and abdominal compartment syndrome, 2) effectively resuscitating patients afflicted by these potentially life-threatening diseases, and 3) preventing the development of intra-abdominal pressure-induced end-organ dysfunction and failure. The currently accepted consensus definitions surrounding the diagnosis and treatment of intra-abdominal hypertension and abdominal compartment syndrome are presented

    Chest- and Waist-Deep Aquatic Plyometric Training and Average Force, Power, and Vertical-Jump Performance

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    Purpose: The purpose of the study was to compare effects of chest- and waist-deep water aquatic plyometrics on average force, power and vertical jump. Methods: Twenty-nine male and female participants were assigned to either a control group or 1 of 2 aquatic groups (waist deep and chest deep) and participated in a 6-wk, twice per wk plyometric training program. Average force and power were measured on a force plate using 3 jumps: squat, countermovement, and drop jump. Vertical-jump heights were also recorded. A repeated-measures ANOVA was used to determine significant differences between testing and groups on average force, power and vertical jump. Results: No significant differences were found with average force and power with the squat, countermovement, and vertical jumps. There were significant changes in drop jump average in the control group from the pretest to posttest. Conclusions: With the water depths chosen and held constant, there appears to be no increased benefit in performance variables

    Spectral and Timing Analysis of the accretion-powered pulsar 4U 1626-67 observed with Suzaku and NuSTAR

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    We present an analysis of the spectral shape and pulse profile of the accretion-powered pulsar 4U 1626-67 observed with Suzaku and NuSTAR during a spin-up state. The pulsar, which experienced a torque reversal to spin-up in 2008, has a spin period of 7.7 s. Comparing the phase-averaged spectra obtained with Suzaku in 2010 and with NuSTAR in 2015, we find that the spectral shape changed between the two observations: the 3-10 keV flux increased by 5% while the 30-60 keV flux decreased significantly by 35%. Phase-averaged and phase-resolved spectral analysis shows that the continuum spectrum observed by NuSTAR is well described by an empirical NPEX continuum with an added broad Gaussian emission component around the spectral peak at 20 keV. Taken together with the observed Pdot value obtained from Fermi/GBM, we conclude that the spectral change between the Suzaku and NuSTAR observations was likely caused by an increase of the accretion rate. We also report the possible detection of asymmetry in the profile of the fundamental cyclotron line. Furthermore, we present a study of the energy-resolved pulse profiles using a new relativistic ray tracing code, where we perform a simultaneous fit to the pulse profiles assuming a two-column geometry with a mixed pencil- and fan-beam emission pattern. The resulting pulse profile decompositions enable us to obtain geometrical parameters of accretion columns (inclination, azimuthal and polar angles) and a fiducial set of beam patterns. This information is important to validate the theoretical predictions from radiation transfer in a strong magnetic field.Comment: 19 pages, 14 figures, Accepted for publication in ApJ on May 5, 201

    Prospective Study Examining Clinical Outcomes Associated with a Negative Pressure Wound Therapy System and Barker’s Vacuum Packing Technique

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    Background The open abdomen has become a common procedure in the management of complex abdominal problems and has improved patient survival. The method of temporary abdominal closure (TAC) may play a role in patient outcome. Methods A prospective, observational, open-label study was performed to evaluate two TAC techniques in surgical and trauma patients requiring open abdomen management: Barker’s vacuum-packing technique (BVPT) and the ABTheraTM open abdomen negative pressure therapy system (NPWT). Study endpoints were days to and rate of 30-day primary fascial closure (PFC) and 30-day all-cause mortality. Results Altogether, 280 patients were enrolled from 20 study sites. Among them, 168 patients underwent at least 48 hours of consistent TAC therapy (111 NPWT, 57 BVPT). The two study groups were well matched demographically. Median days to PFC were 9 days for NPWT versus 12 days for BVPT (p = 0.12). The 30-day PFC rate was 69 % for NPWT and 51 % for BVPT (p = 0.03). The 30-day all-cause mortality was 14 % for NPWT and 30 % for BVPT (p = 0.01). Multivariate logistic regression analysis identified that patients treated with NPWT were significantly more likely to survive than the BVPT patients [odds ratio 3.17 (95 % confidence interval 1.22–8.26); p = 0.02] after controlling for age, severity of illness, and cumulative fluid administration. Conclusions Active NPWT is associated with significantly higher 30-day PFC rates and lower 30-day all-cause mortality among patients who require an open abdomen for at least 48 h during treatment for critical illness
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