999 resultados para spray volume
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OBJECTIVE: To assess the accuracy of a semiautomated 3D volume reconstruction method for organ volume measurement by postmortem MRI. METHODS: This prospective study was approved by the institutional review board and the infants' parents gave their consent. Postmortem MRI was performed in 16 infants (1 month to 1 year of age) at 1.5 T within 48 h of their sudden death. Virtual organ volumes were estimated using the Myrian software. Real volumes were recorded at autopsy by water displacement. The agreement between virtual and real volumes was quantified following the Bland and Altman's method. RESULTS: There was a good agreement between virtual and real volumes for brain (mean difference: -0.03% (-13.6 to +7.1)), liver (+8.3% (-9.6 to +26.2)) and lungs (+5.5% (-26.6 to +37.6)). For kidneys, spleen and thymus, the MRI/autopsy volume ratio was close to 1 (kidney: 0.87±0.1; spleen: 0.99±0.17; thymus: 0.94±0.25), but with a less good agreement. For heart, the MRI/real volume ratio was 1.29±0.76, possibly due to the presence of residual blood within the heart. The virtual volumes of adrenal glands were significantly underestimated (p=0.04), possibly due to their very small size during the first year of life. The percentage of interobserver and intraobserver variation was lower or equal to 10%, but for thymus (15.9% and 12.6%, respectively) and adrenal glands (69% and 25.9%). CONCLUSIONS: Virtual volumetry may provide significant information concerning the macroscopic features of the main organs and help pathologists in sampling organs that are more likely to yield histological findings.
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Iowa features an extensive surface transportation system, with more than 110,000 miles of roadway, most of which is under the jurisdiction of local agencies. Given that Iowa is a lower-population state, most of this mileage is located in rural areas that exhibit low traffic volumes of less than 400 vehicles per day. However, these low-volume rural roads also account for about half of all recorded traffic crashes in Iowa, including a high percentage of fatal and major injury crashes. This study was undertaken to examine these crashes, identify major contributing causes, and develop low-cost strategies for reducing the incidence of these crashes. Iowa’s extensive crash and roadway system databases were utilized to obtain needed data. Using descriptive statistics, a test of proportions, and crash modeling, various classes of rural secondary roads were compared to similar state of Iowa controlled roads in crash frequency, severity, density, and rate for numerous selected factors that could contribute to crashes. The results of this study allowed the drawing of conclusions as to common contributing factors for crashes on low-volume rural roads, both paved and unpaved. Due to identified higher crash statistics, particular interest was drawn to unpaved rural roads with traffic volumes greater than 100 vehicles per day. Recommendations for addressing these crashes with low-cost mitigation are also included. Because of the isolated nature of traffic crashes on low-volume roads, a systemic or mass action approach to safety mitigation was recommended for an identified subset of the entire system. In addition, future development of a reliable crash prediction model is described.
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Part 6 of the Manual on Uniform Traffic Control Devices (MUTCD) describes several types of channelizing devices that can be used to warn road users and guide them through work zones; these devices include cones, tubular markers, vertical panels, drums, barricades, and temporary raised islands. On higher speed/volume roadways, drums and/or vertical panels have been popular choices in many states, due to their formidable appearance and the enhanced visibility they provide when compared to standard cones. However, due to their larger size, drums also require more effort and storage space to transport, deploy and retrieve. Recent editions of the MUTCD have introduced new devices for channelizing; specifically of interest for this study is a taller (>36 inches) but thinner cone. While this new device does not offer a comparable target value to that of drums, the new devices are significantly larger than standard cones and they offer improved stability as well. In addition, these devices are more easily deployed and stored than drums and they cost less. Further, for applications previously using both drums and tall cones, the use of tall cones only provides the ability for delivery and setup by a single vehicle. An investigation of the effectiveness of the new channelizing devices provides a reference for states to use in selecting appropriate traffic control for high speed, high volume applications, especially for short term or limited duration exposures. This study includes a synthesis of common practices by state DOTs, as well as daytime and nighttime field observations of driver reactions using video detection equipment. The results of this study are promising for the day and night performance of the new tall cones, comparing favorably to the performance of drums when used for channelizing in tapers. The evaluation showed no statistical difference in merge distance and location, shy distance, or operating speed in either daytime or nighttime conditions. The study should provide a valuable resource for state DOTs to utilize in selecting the most effective channelizing device for use on high speed/high volume roadways where timely merging by drivers is critical to safety and mobility.
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The role of endothelin (ET) receptors was tested in volume-stimulated atrial natriuretic factor (ANF) secretion in conscious rats. Mean ANF responses to slow infusions (3 x 3.3 ml/8 min) were dose dependently reduced (P < 0.05) by bosentan (nonselective ET-receptor antagonist) from 64.1 +/- 18.1 (SE) pg/ml (control) to 52.6 +/- 16.1 (0.033 mg bosentan/rat), 16.1 +/- 7.6 (0. 33 mg/rat), and 11.6 +/- 6.5 pg/ml (3.3 mg/rat). The ET-A-receptor antagonist BQ-123 (1 mg/rat) had no effect relative to DMSO controls, whereas the putative ET-B antagonist IRL-1038 (0.1 mg/rat) abolished the response. In a second protocol, BQ-123 (>/=0.5 mg/rat) nonsignificantly reduced the peak ANF response (106.1 +/- 23.0 pg/ml) to 74.0 +/- 20.5 pg/ml for slow infusions (3.5 ml/8.5 min) but reduced the peak response (425.3 +/- 58.1 pg/ml) for fast infusions (6.6 ml/1 min) by 49.9% (P < 0.001) and for 340 pmoles ET-1 (328.8 +/- 69.5 pg/ml) by 83.5% (P < 0.0001). BQ-123 abolished the ET-1-induced increase in arterial pressure (21.8 +/- 5.2 mmHg at 1 min). Changes in central venous pressure were similar for DMSO and BQ-123 (slow: 0.91 and 1.14 mmHg; fast: 4.50 and 4.13 mmHg). The results suggest 1) ET-B receptors mainly mediate the ANF secretion to slow volume expansions of <1.6%/min; and 2) ET-A receptors mainly mediate the ANF response to acute volume overloads.
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BACKGROUND: Liver remnant volumes after major hepatic resection and graft volumes for liver transplantation correlate with surgical outcome. The relative contributions of the hepatic segments to total liver volume (TLV) are not well established. METHODS: TLV and hepatic segment volumes were measured with computed tomography (CT) in 102 patients without liver disease who underwent CT for conditions unrelated to the liver or biliary tree. RESULTS: TLV ranged from 911 to 2729 cm(3). On average, the right liver (segments V, VI, VII, and VIII) contributed approximately two thirds of TLV (997+/-279 cm(3)), and the left liver (segments II, III and IV) contributed approximately one third of TLV (493+/-127 cm(3)). Bisegment II+III (left lateral section) contributed about half the volume of the left liver (242+/-79 cm(3)), or 16% of TLV. Liver volumes varied significantly between patients--the right liver varied from 49% to 82% of TLV, the left liver, 17% to 49% of TLV, and bisegment II+III (left lateral section) 5% to 27% of TLV. Bisegment II+III contributed less than 20% of TLV in more than 75% of patients and the left liver contributed 25% or less of TLV in more than 10% of patients. DISCUSSION: There is clinically significant interpatient variation in hepatic volumes. Therefore, in the absence of appreciable hypertrophy, we recommend routine measurement of the future liver remnant before extended right hepatectomy (right trisectionectomy) and in selected patients before right hepatectomy if a small left liver is anticipated.
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BACKGROUND AND OBJECTIVE: Key factors of Fast Track (FT) programs are fluid restriction and epidural analgesia (EDA). We aimed to challenge the preconception that the combination of fluid restriction and EDA might induce hypotension and renal dysfunction. METHODS: A recent randomized trial (NCT00556790) showed reduced complications after colectomy in FT patients compared with standard care (SC). Patients with an effective EDA were compared with regard to hemodynamics and renal function. RESULTS: 61/76 FT patients and 59/75 patients in the SC group had an effective EDA. Both groups were comparable regarding demographics and surgery-related characteristics. FT patients received significantly less i.v. fluids intraoperatively (1900 mL [range 1100-4100] versus 2900 mL [1600-5900], P < 0.0001) and postoperatively (700 mL [400-1500] versus 2300 mL [1800-3800], P < 0.0001). Intraoperatively, 30 FT compared with 19 SC patients needed colloids or vasopressors, but this was statistically not significant (P = 0.066). Postoperative requirements were low in both groups (3 versus 5 patients; P = 0.487). Pre- and postoperative values for creatinine, hematocrit, sodium, and potassium were similar, and no patient developed renal dysfunction in either group. Only one of 82 patients having an EDA without a bladder catheter had urinary retention. Overall, FT patients had fewer postoperative complications (6 versus 20 patients; P = 0.002) and a shorter median hospital stay (5 [2-30] versus 9 d [6-30]; P< 0.0001) compared with the SC group. CONCLUSIONS: Fluid restriction and EDA in FT programs are not associated with clinically relevant hemodynamic instability or renal dysfunction.
Bond Contribution to Whitetopping Performance on Low Volume Roads, Construction Report, HR-341, 1993
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This research was initiated in 1991 as a part of a whitetopping project to study the effectiveness of various techniques to enhance bond strength between a new Portland cement concrete (PCC) overlay and an existing asphalt cement concrete (ACC) pavement surface. A 1,676 m (5,500 ft) section of county road R16 in Dallas County, Iowa was divided into 12 test sections. The various techniques used to enhance bond were power brooming, power brooming with air blast, milling, cement and water grout, and emulsion tack coat. As a part of these bonding techniques, two pavement thicknesses were placed; two different concrete proportions were used; and two sections were planed to a uniform cross-slope.
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Comprend : Essai sur les romans historiques et du moyen âge...
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The primary objective of this project is to develop a design manual that would aid the county or municipal engineer in making structurally sound bridge strengthening or replacement decisions. The contents of this progress report are related only to Phase I of the study and deal primarily with defining the extent of the bridge problem in Iowa. In addition, the types of bridges to which the manual should be directed have been defined.
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OBJECTIVES:: For certain major operations, inpatient mortality risk is lower in high-volume hospitals than those in low-volume hospitals. Extending the analysis to a broader range of interventions and outcomes is necessary before adopting policies based on minimum volume thresholds. METHODS:: Using the United States 2004 Nationwide Inpatient Sample, we assessed the effect of intervention-specific and overall hospital volume on surgical complications, potentially avoidable reoperations, and deaths across 1.4 million interventions in 353 hospitals. Outcome variations across hospitals were analyzed through a 3-level hierarchical logistic regression model (patients, surgical interventions, and hospitals), which took into account interventions on multiple organs, 144 intervention categories, and structural hospital characteristics. Discriminative performance and calibration were good. RESULTS:: Hospitals with more experience in a given intervention had similar reoperation rates but lower mortality and complication rates: odds ratio per volume deciles 0.93 and 0.97. However, the benefit was limited to heart surgery and a small number of other operations. Risks were higher for hospitals that performed more interventions overall: odds ratio per 1000 for each event was approximately 1.02. Even after adjustment for specific volume, mortality varied substantially across both high- and low-volume hospitals. CONCLUSION:: Although the link between specific volume and certain inpatient outcomes suggests that specialization might help improve surgical safety, the variable magnitude of this link and the heterogeneity of hospital effect do not support the systematic use of volume-based referrals. It may be more efficient to monitor risk-adjusted postoperative outcomes and to investigate facilities with worse than expected outcomes.