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Sample records for ventilation perfusion imbalance

  1. EFFECT OF VENTILATION AND PERFUSION IMBALANCE ON INERT GAS REBREATHING VARIABLES

    EPA Science Inventory

    The effects of ventilation-to-perfusion (Va/Qc) maldistribution within the lungs on measured multiple gas rebreathing variables were studied in 14 dogs. The rebreathing method (using He, C18C, and C2H2) allows for measurements of pulmonary capillary blood flow (Qc), diffusing cap...

  2. Pulmonary ventilation/perfusion scan

    MedlinePLUS

    V/Q scan; Ventilation/perfusion scan; Lung ventilation/perfusion scan ... A pulmonary ventilation/perfusion scan is actually two tests. They may be done separately or together. During the perfusion scan, a ...

  3. Lung Ventilation/Perfusion Scan

    MedlinePLUS

    ... the NHLBI on Twitter. What Is a Lung Ventilation/Perfusion Scan? A lung ventilation/perfusion scan, or VQ scan, is a test ... A VQ scan involves two types of scans: ventilation and perfusion. The ventilation scan shows where air ...

  4. Measurement of continuous distributions of ventilation-perfusion ratios - Theory

    NASA Technical Reports Server (NTRS)

    Wagner, P. D.; Saltzman, H. A.; West, J. B.

    1974-01-01

    The resolution of the technique considered is sufficient to describe smooth distributions containing blood flow to unventilated regions (shunt), ventilation to unperfused regions (dead space), and up to three additional modes over the range of finite ventilation-perfusion ratios. In particular, areas whose ventilation-perfusion ratios are low can be separated from unventilated regions and those whose ventilation-perfusion ratios are high can similarly be distinguished from unperfused areas.

  5. Automated quantitative analysis of ventilation-perfusion lung scintigrams

    SciTech Connect

    Burton, G.H.; Vernon, P.; Seed, W.A.

    1984-05-01

    An automated computer analysis of ventilation (Kr-81m) and perfusion (Tc-99m) lung images has been devised that produces a graphical image of the distribution of ventilation and perfusion, and of ventilation-perfusion ratios. The analysis has overcome the following problems: the identification of the midline between two lungs and the lung boundaries, the exclusion of extrapulmonary radioactivity, the superimposition of lung images of different sizes, and the format for presentation of the data. Therefore, lung images of different sizes and shapes may be compared with each other. The analysis has been used to develop normal ranges from 55 volunteers. Comparison of younger and older age groups of men and women show small but significant differences in the distribution of ventilation and perfusion, but no differences in ventilation-perfusion ratios.

  6. Ventilation-perfusion matching during exercise

    NASA Technical Reports Server (NTRS)

    Wagner, P. D.

    1992-01-01

    In normal subjects, exercise widens the alveolar-arterial PO2 difference (P[A-a]O2) despite a more uniform topographic distribution of ventilation-perfusion (VA/Q) ratios. While part of the increase in P(A-a)O2 (especially during heavy exercise) is due to diffusion limitation, a considerable amount is caused by an increase in VA/Q mismatch as detected by the multiple inert gas elimination technique. Why this occurs is unknown, but circumstantial evidence suggests it may be related to interstitial pulmonary edema rather than to factors dependent on ventilation, airway gas mixing, airway muscle tone, or pulmonary vascular tone. In patients with lung disease, the gas exchange consequences of exercise are variable. Thus, arterial PO2 may increase, remain the same, or fall. In general, patients with advanced chronic obstructive pulmonary disease (COPD) or interstitial fibrosis who exercise show a fall in PO2. This is usually not due to worsening VA/Q relationships but mostly to the well-known fall in mixed venous PO2, which itself results from a relatively smaller increase in cardiac output than VO2. However, in interstitial fibrosis (but not COPD), there is good evidence that a part of the fall in PO2 on exercise is caused by alveolar-capillary diffusion limitation of O2 transport; in COPD (but not interstitial fibrosis), a frequent additional contributing factor to the hypoxemia of exercise is an inadequate ventilatory response, such that minute ventilation does not rise as much as does CO2 production or O2 uptake, causing arterial PCO2 to increase and PO2 to fall.

  7. Teaching Ventilation/Perfusion Relationships in the Lung

    ERIC Educational Resources Information Center

    Glenny, Robb W.

    2008-01-01

    This brief review is meant to serve as a refresher for faculty teaching respiratory physiology to medical students. The concepts of ventilation and perfusion matching are some of the most challenging ideas to learn and teach. Some strategies to consider in teaching these concepts are, first, to build from simple to more complex by starting with a…

  8. Topographic distribution of pulmonary ventilation and perfusion in the horse

    SciTech Connect

    Amis, T.C.; Pascoe, J.R.; Hornof, W.

    1984-08-01

    The regional distribution of ventilation to perfusion ratios (VA/Q) in the lungs of 8 healthy standing Thoroughbred geldings (4.4 +/- 1.5 years, 465.7 +/- 46.6 kg) was studied, using steady-state inhalation and IV infusion of the radioactive gas krypton-81m. The VA/Q was uniformly distributed within a vertical lung strip centered over the 9th rib on the right side. Ventilation per unit of alveolar volume (V/VA) assessed from the clearance of inhaled radioactive gas in 5 horses increased from 0.49 +/- 0.13 (arbitrary units) in nondependent lung zones to 1.45 +/- 0.16 in dependent lung zones. Seemingly, a vertical gradient of pulmonary ventilation exists in the horse that is matched by a similar gradient of perfusion.

  9. Heterogeneity and Matching of Ventilation and Perfusion within Anatomical Lung Units in Rats

    PubMed Central

    Glenny, Robb W.; Bauer, Christian; Hofmanninger, Johannes; Lamm, Wayne J.; Krueger, Melissa A.; Beichel, Reinhard R.

    2013-01-01

    Prior studies exploring the spatial distributions of ventilation and perfusion have partitioned the lung into discrete regions not constrained by anatomical boundaries and may blur regional differences in perfusion and ventilation. To characterize the anatomical heterogeneity of regional ventilation and perfusion, we administered fluorescent microspheres to mark regional ventilation and perfusion in 5 Sprague-Dawley rats and then using highly automated computer algorithms, partitioned the lungs into regions defined by anatomical structures identified in the images. The anatomical regions ranged in size from the nearacinar to the lobar level. Ventilation and perfusion were well correlated at the smallest anatomical level. Perfusion and ventilation heterogeneity were relatively less in rats compared to data previously published in larger animals. The more uniform distributions may be due to a smaller gravitational gradient and/or the fewer number of generations in the distribution trees before reaching the level of gas exchange, making regional matching of ventilation and perfusion less extensive in small animals. PMID:23942308

  10. Ventilation-perfusion matching in long-term microgravity

    NASA Technical Reports Server (NTRS)

    Verbandt, Y.; Wantier, M.; Prisk, G. K.; Paiva, M.; West, J. B. (Principal Investigator)

    2000-01-01

    We studied the ventilation-perfusion matching pattern in normal gravity (1 G) and short- and long-duration microgravity (microG) using the cardiogenic oscillations in the sulfur hexaflouride (SF(6)) and CO(2) concentration signals during the phase III portion of vital capacity single-breath washout experiments. The signal power of the cardiogenic concentration variations was assessed by spectral analysis, and the phase angle between the oscillations of the two simultaneously expired gases was obtained through cross-correlation. For CO(2), a significant reduction of cardiogenic power was observed in microG, with respect to 1 G, but the reduction was smaller and more variable in the case of SF(6). A shift from an in-phase condition in 1 G to an out-of-phase condition was found for both short- and long-duration microG. We conclude that, although the distribution of ventilation and perfusion becomes more homogeneous in microG, significant inhomogeneities persist and that areas of high perfusion become associated with areas of relatively lower ventilation. In addition, these modifications seem to remain constant during long-term exposure to microG.

  11. Effect of Endobronchial Valve Therapy on Pulmonary Perfusion and Ventilation Distribution

    PubMed Central

    Pizarro, Carmen; Ahmadzadehfar, Hojjat; Essler, Markus; Tuleta, Izabela; Fimmers, Rolf; Nickenig, Georg; Skowasch, Dirk

    2015-01-01

    Introduction Endoscopic lung volume reduction (ELVR) is an emerging therapy for emphysematous COPD. However, any resulting changes in lung perfusion and ventilation remain undetermined. Here, we report ELVR-mediated adaptations in lung perfusion and ventilation, as investigated by means of pulmonary scintigraphy. Methods In this observational study, we enrolled 26 patients (64.9±9.4 yrs, 57.7% male) with COPD heterogeneous emphysema undergoing ELVR with endobronchial valves (Zephyr, Pulmonx, Inc.). Mean baseline FEV1 and RV were 32.9% and 253.8% predicted, respectively. Lung scintigraphy was conducted prior to ELVR and eight weeks thereafter. Analyses of perfusion and ventilation shifts were performed and complemented by correlation analyses between paired zones. Results After ELVR, target zone perfusion showed a mean relative reduction of 43.32% (p<0.001), which was associated with a significant decrease in target zone ventilation (p<0.001). Perfusion of the contralateral untreated zone and of the contralateral total lung exhibited significant increases post-ELVR (p = 0.002 and p = 0.005, respectively); both correlated significantly with the corresponding target zone perfusion adaptations. Likewise, changes in target zone ventilation correlated significantly with ventilatory changes in the contralateral untreated zone and the total contralateral lung (Pearson’s r: ?0.42, p = 0.04 and Pearson’s r: ?0.42, p = 0.03, respectively). These effects were observed in case of clinical responsiveness to ELVR, as assessed by changes in the six-minute walk test distance. Discussion ELVR induces a relevant decrease in perfusion and ventilation of the treated zone with compensatory perfusional and ventilatory redistribution to the contralateral lung, primarily to the non-concordant, contralateral zone. PMID:25822624

  12. Comparison of 4-Dimensional Computed Tomography Ventilation With Nuclear Medicine Ventilation-Perfusion Imaging: A Clinical Validation Study

    SciTech Connect

    Vinogradskiy, Yevgeniy; Koo, Phillip J.; Castillo, Richard; Castillo, Edward; Guerrero, Thomas; Gaspar, Laurie E.; Miften, Moyed; Kavanagh, Brian D.

    2014-05-01

    Purpose: Four-dimensional computed tomography (4DCT) ventilation imaging provides lung function information for lung cancer patients undergoing radiation therapy. Before 4DCT-ventilation can be implemented clinically it needs to be validated against an established imaging modality. The purpose of this work was to compare 4DCT-ventilation to nuclear medicine ventilation, using clinically relevant global metrics and radiologist observations. Methods and Materials: Fifteen lung cancer patients with 16 sets of 4DCT and nuclear medicine ventilation-perfusion (VQ) images were used for the study. The VQ-ventilation images were acquired in planar mode using Tc-99m-labeled diethylenetriamine-pentaacetic acid aerosol inhalation. 4DCT data, spatial registration, and a density-change-based model were used to compute a 4DCT-based ventilation map for each patient. The percent ventilation was calculated in each lung and each lung third for both the 4DCT and VQ-ventilation scans. A nuclear medicine radiologist assessed the VQ and 4DCT scans for the presence of ventilation defects. The VQ and 4DCT-based images were compared using regional percent ventilation and radiologist clinical observations. Results: Individual patient examples demonstrate good qualitative agreement between the 4DCT and VQ-ventilation scans. The correlation coefficients were 0.68 and 0.45, using the percent ventilation in each individual lung and lung third, respectively. Using radiologist-noted presence of ventilation defects and receiver operating characteristic analysis, the sensitivity, specificity, and accuracy of the 4DCT-ventilation were 90%, 64%, and 81%, respectively. Conclusions: The current work compared 4DCT with VQ-based ventilation using clinically relevant global metrics and radiologist observations. We found good agreement between the radiologist's assessment of the 4DCT and VQ-ventilation images as well as the percent ventilation in each lung. The agreement lessened when the data were analyzed on a regional level. Our study presents an important step for the integration of 4DCT-ventilation into thoracic clinical practice.

  13. Bronchogenic cyst causing a unilateral ventilation-perfusion defect on lung scan

    SciTech Connect

    Berkowitz, K.A.; Fleischman, J.K.; Smith, R.L.

    1988-06-01

    A 37-year-old woman had pleuritic chest pain, dyspnea, and normal findings on chest roentgenogram. Lung scan showed markedly diminished perfusion to the right lung with a matched ventilatory defect. Further evaluation revealed a bronchogenic cyst. After resection, the lung scan was normal. To our knowledge, this is the first report of a bronchogenic cyst causing a reversible, unilateral ventilation-perfusion defect on lung scan.

  14. Unusual ventilation perfusion scintigram in a case of immunologic pulmonary edema clinically simulating pulmonary embolism

    SciTech Connect

    Campeau, R.J.; Faust, J.M.; Ahmad, S.

    1987-11-01

    A case of immunologic pulmonary edema secondary to hydrochlorothiazide allergy developed in a 55-year-old woman that clinically simulated pulmonary embolism. The patient had abnormal washin images with normal washout images on an Xe-133 ventilation study. On the perfusion study, large bilateral central and posterior perfusion defects were present that showed an unusual mirror image pattern on the lateral and posterior oblique views. Resolution of radiographic and scintigraphic abnormalities occurred over a 3-day period in conjunction with corticosteroid therapy.

  15. Distribution of pulmonary ventilation and perfusion during short periods of weightlessness

    NASA Technical Reports Server (NTRS)

    Michels, D. B.; West, J. B.

    1978-01-01

    Airborne experiments were conducted on four trained normal male subjects (28-40 yr) to study pulmonary function during short periods (22-27 sec) of zero gravity obtained by flying a jet aircraft through appropriate parabolic trajectories. The cabin was always pressurized to a sea-level altitude. The discussion is limited to pulmonary ventilation and perfusion. The results clearly demonstrate that gravity is the major factor causing nonuniformity in the topographical distribution of pulmonary ventilation. More importantly, the results suggest that virtually all the topographical nonuniformity of ventilation, blood flow, and lung volume observed under 1-G conditions are eliminated during short periods of zero gravity.

  16. A General Approach to the Evaluation of Ventilation-Perfusion Ratios in Normal and Abnormal Lungs

    ERIC Educational Resources Information Center

    Wagner, Peter D.

    1977-01-01

    Outlines methods for manipulating multiple gas data so as to gain the greatest amount of insight into the properties of ventilation-perfusion distributions. Refers to data corresponding to normal and abnormal lungs. Uses a two-dimensional framework with the respiratory gases of oxygen and carbon dioxide. (CS)

  17. Lobe-based Estimating Ventilation and Perfusion from 3D CT scans of the Lungs

    E-print Network

    Warren, Joe

    scanners are capable of computing approximately 10 3D scans, each with millimeter resolution, during a 3Lobe-based Estimating Ventilation and Perfusion from 3D CT scans of the Lungs Travis McPhail Joe for lung cancer includes surgical removal or radiation therapy. 3D imaging technologies such CT, MRI

  18. Computation of ventilation-perfusion ratio with Kr-81m in pulmonary embolism

    SciTech Connect

    Meignan, M.; Simonneau, G.; Oliveira, L.; Harf, A.; Cinotti, L.; Cavellier, J.F.; Duroux, P.; Ansquer, J.C.; Galle, P.

    1984-02-01

    Diagnostic difficulties occur in pulmonary embolism (PE) during visual analysis of ventilation-perfusion images in matched defects or in chronic obstructive lung disease (COPD). In 44 patients with angiographically confirmed PE and in 40 patients with COPD, the regional ventilation-perfusion ratios (V/Q) were therefore computed using krypton-81m for each perfusion defect, and were displayed in a functional image. In patients with PE and mismatched defects, a high V/Q (1.96) was observed. A V/Q > 1.25 was also found in nine of 11 patients having PE and indeterminate studies (studies with perfusion abnormalities matched by radiographic abnormalities). COPD was characterized by matched defects and low V/Q. The percentage of patients correctly classified as having PE or COPD increased from 56% when considering the match or mismatched character to 88% when based on a V/Q of 1.25 in the region of the perfusion defect. This quantitative analysis, therefore, seems useful in classifying patients with scintigraphic suspicion of PE.

  19. Ventilation-perfusion scintigraphy in an adult with congenital unilateral hyperlucent lung

    SciTech Connect

    Wegener, W.A.; Velchik, M.G. )

    1990-10-01

    A variety of congenital and acquired etiologies can give rise to the radiographic finding of a unilateral hyperlucent lung. An unusual case of congenital lobar emphysema diagnosed in a young adult following the initial discovery of a hyperexpanded, hyperlucent lung is reported. Although subsequent bronchoscopy and radiologic studies detailed extensive anatomic abnormalities, functional imaging also played an important role in arriving at this rare diagnosis. In particular, ventilation-perfusion scintigraphy identified the small contralateral lung as the functional lung and helped narrow the differential diagnosis to etiologies involving obstructive airway disorders.

  20. Ventilation-perfusion relationships in the lung during head-out water immersion

    NASA Technical Reports Server (NTRS)

    Derion, Toniann; Guy, Harold J. B.; Tsukimoto, Koichi; Schaffartzik, Walter; Prediletto, Renato; Poole, David C.; Knight, Douglas R.; Wagner, Peter D.

    1992-01-01

    Mechanisms of altered pulmonary gas exchange during water immersion were studied in 12 normal males: 6 young (aged 20-29) and 6 older (aged 40-45). It is concluded that, in young subjects with closing volume (CV) less than expiratory reserve volume (ERV), gas exchange was enhanced during immersion, because normal ventilation-perfusion relations were preserved, and by mass balance, the ventilation/O2 uptake changes elevated arterial P(O2). In older males with CV greater than ERV and 52 percent of tidal volume below CV, immersion-induced airways closure during tidal breathing was associated with minimally increased shunt that did not significantly impair gas exchange. It is suggested that airways closure of this degree is of little importance to gas exchange.

  1. Anoxic ventilation improves systemic perfusion during extracorporeal circulation with uncontrolled systemic-to-pulmonary shunt.

    PubMed

    Hammel, James M; Deptula, Joseph; Hunt, Peter W; Lang, Haili; Duncan, Kim F

    2007-01-01

    Uncontrolled systemic-to-pulmonary shunt results in decreased systemic flow during extracorporeal life support (ECLS). Ligation of systemic-to-pulmonary shunts during ECLS is associated with poor outcome and is not always readily achieved. In ex vivo preparations, alveolar hypoxia results in pulmonary vasoconstriction despite normoxic pulmonary perfusate. We hypothesized that anoxic ventilation would result in reduced pulmonary shunting and increased systemic flow during ECLS in piglets with systemic-to-pulmonary shunt. Four piglets were placed on ECLS with right and left atrial drainage. A shunt was created between the bicarotid trunk and pulmonary artery, using 5-mm ePTFE tubing. Inspired oxygen was reduced to <1% for 10 minutes, then returned to room air; pH, hematocrit, temperature, ventilatory pressures, and total pump flow were maintained constant. Systemic arterial pressure and right atrial return volume and hemoglobin saturation were measured: All decreased significantly upon shunt unclamping. Anoxic ventilation caused increased systemic pressure (34 vs. 28 mm Hg, p < 0.05), flow (335 vs. 278 mL/min, p < 0.05), and systemic venous saturation (53% vs. 48%, p = 0.13) compared with room air ventilation. In conclusion, anoxic ventilation during normoxic ECLS in subjects with systemic-to-pulmonary shunts results in a significant and potentially clinically useful reduction in pulmonary shunting. PMID:17413566

  2. Regional ventilation-perfusion distribution is more uniform in the prone position

    NASA Technical Reports Server (NTRS)

    Mure, M.; Domino, K. B.; Lindahl, S. G.; Hlastala, M. P.; Altemeier, W. A.; Glenny, R. W.

    2000-01-01

    The arterial blood PO(2) is increased in the prone position in animals and humans because of an improvement in ventilation (VA) and perfusion (Q) matching. However, the mechanism of improved VA/Q is unknown. This experiment measured regional VA/Q heterogeneity and the correlation between VA and Q in supine and prone positions in pigs. Eight ketamine-diazepam-anesthetized, mechanically ventilated pigs were studied in supine and prone positions in random order. Regional VA and Q were measured using fluorescent-labeled aerosols and radioactive-labeled microspheres, respectively. The lungs were dried at total lung capacity and cubed into 603-967 small ( approximately 1.7-cm(3)) pieces. In the prone position the homogeneity of the ventilation distribution increased (P = 0.030) and the correlation between VA and Q increased (correlation coefficient = 0.72 +/- 0.08 and 0.82 +/- 0.06 in supine and prone positions, respectively, P = 0.03). The homogeneity of the VA/Q distribution increased in the prone position (P = 0.028). We conclude that the improvement in VA/Q matching in the prone position is secondary to increased homogeneity of the VA distribution and increased correlation of regional VA and Q.

  3. Validation of measurements of ventilation-to-perfusion ratio inequality in the lung from expired gas

    NASA Technical Reports Server (NTRS)

    Prisk, G. Kim; Guy, Harold J B.; West, John B.; Reed, James W.

    2003-01-01

    The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (Va/Q) inequality in the lung. To further validate this estimate, we examined three measures of Va/Q inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions and after exposure to aerosolized methacholine. These measurements were then compared with arterial blood gases and with measurements of Va/Q inhomogeneity obtained using the multiple inert gas elimination technique. The slope of the instantaneous respiratory exchange ratio (R slope) vs. expired volume was poorly correlated with independent measures, probably because of the curvilinear nature of the relationship due to continuing gas exchange. When R was converted to the intrabreath Va/Q (iV/Q), the best index was the slope of iV/Q vs. volume over phase III (iV/Q slope). This was strongly correlated with independent measures, especially those relating to inhomogeneity of perfusion. The correlations for iV/Q slope and R slope considerably improved when only the first half of phase III was considered. We conclude that a useful noninvasive measurement of Va/Q inhomogeneity can be derived from the intrabreath respiratory exchange ratio.

  4. Lung [18F]fluorodeoxyglucose uptake and ventilation-perfusion mismatch in the early stage of experimental acute smoke inhalation

    PubMed Central

    Musch, Guido; Winkler, Tilo; Harris, R. Scott; Vidal Melo, Marcos F.; Wellman, Tyler J.; de Prost, Nicolas; Kradin, Richard L.; Venegas, Jose G.

    2014-01-01

    Background Acute lung injury (ALI) occurs in a third of patients with smoke inhalation injury. Its clinical manifestations usually do not appear until 48 to 72 h after inhalation. Identifying inflammatory changes that occur in pulmonary parenchyma earlier than that could provide insight into the pathogenesis of smoke-induced ALI. Furthermore, noninvasive measurement of such changes might lead to earlier diagnosis and treatment. Because glucose is the main source of energy for pulmonary inflammatory cells, we hypothesized that its pulmonary metabolism is increased shortly after smoke inhalation, when classic manifestations of ALI are not yet expected. Methods In five sheep we induced unilateral injury with 48 breaths of cotton smoke while the contralateral lung served as control. We used positron emission tomography with: 1) [18F]fluorodeoxyglucose to measure pulmonary inflammatory cell metabolic activity; and 2) [13N]nitrogen in saline to measure shunt and ventilation-perfusion distributions separately in the smoke-exposed and control lungs. Results The pulmonary [18F]fluorodeoxyglucose uptake rate was increased at 4 h after smoke inhalation (mean ± SD: 0.0031 ± 0.0013 vs. 0.0026 ± 0.0010 min?1, P < 0.05) mainly as a result of increased glucose phosphorylation. At this stage there was no worsening in lung aeration or shunt. However, there was a shift of perfusion toward units with lower ventilation-to-perfusion ratio (mean ratio ± SD: 0.82 ± 0.10 vs. 1.12 ± 0.02, P < 0.05) and increased heterogeneity of the ventilation-perfusion distribution (mean ± SD: 0.21 ± 0.07 vs. 0.13 ± 0.01, P < 0.05). Conclusion Using noninvasive imaging we demonstrated that increased pulmonary [18F]fluorodeoxyglucose uptake and ventilation-perfusion mismatch occur early after smoke inhalation. PMID:24051392

  5. Alveolar ventilation to perfusion heterogeneity and diffusion impairment in a mathematical model of gas exchange

    NASA Technical Reports Server (NTRS)

    Vidal Melo, M. F.; Loeppky, J. A.; Caprihan, A.; Luft, U. C.

    1993-01-01

    This study describes a two-compartment model of pulmonary gas exchange in which alveolar ventilation to perfusion (VA/Q) heterogeneity and impairment of pulmonary diffusing capacity (D) are simultaneously taken into account. The mathematical model uses as input data measurements usually obtained in the lung function laboratory. It consists of two compartments and an anatomical shunt. Each compartment receives fractions of alveolar ventilation and blood flow. Mass balance equations and integration of Fick's law of diffusion are used to compute alveolar and blood O2 and CO2 values compatible with input O2 uptake and CO2 elimination. Two applications are presented. The first is a method to partition O2 and CO2 alveolar-arterial gradients into VA/Q and D components. The technique is evaluated in data of patients with chronic obstructive pulmonary disease (COPD). The second is a theoretical analysis of the effects of blood flow variation in alveolar and blood O2 partial pressures. The results show the importance of simultaneous consideration of D to estimate VA/Q heterogeneity in patients with diffusion impairment. This factor plays an increasing role in gas alveolar-arterial gradients as severity of COPD increases. Association of VA/Q heterogeneity and D may produce an increase of O2 arterial pressure with decreasing QT which would not be observed if only D were considered. We conclude that the presented computer model is a useful tool for description and interpretation of data from COPD patients and for performing theoretical analysis of variables involved in the gas exchange process.

  6. Krypton 81m ventilation/perfusion ratios (V/Q) measured in lateral decubitus in pulmonary embolism (P. E. )

    SciTech Connect

    Meignan, M.; Cinotti, L.; Harf, A.; Oliveira, L.; Simonneau, G.

    1984-01-01

    In normal subjects lateral decubitis induces in both independent (lower) and nondependent lung (upper), major changes in perfusion, ventilation and V/Q ratios which can be studied with the short life radioisotope Krypton 81m. Regional V/Q are computed from ventilation and perfusion scans, successively obtained with a gamma camera linked to a computer by continuous inhalation or infusion of this gas during tidal breathing. They were displayed as a color coded functional image. To assess the effect of posture on V/Q in P.E. and other diseases which decrease the regional perfusion, 32 patients with unilateral lung diseases were studied in supine posture and both lateral decubitis: 8 with proved P.E., (3 out of them having radiological opacity matching the perfusion defect), 9 with bullous emphysema, 6 with bronchogenic carcinoma, 9 with acute bacterial pneumonia. V/Q were computed in the region of the perfusion defect. In P.E. the mean V/Q was high (1.92 +- 0.6 SD), and did not change whatever the posture. Conversely major changes of V/Q were induced with postural changes in bullous emphysema and lung carcinoma whatever the V/Q in patient supine. In pneumonia low V/Q were observed in supine posture (.73 +- .2). They decreased significantly when the pneumonia was dependent (.53 +- .2 p < 0.02) and increased in the controlateral decubitis (1.07 +- .3, p < 0.001). Since posture has no or little effect on regional V/Q in P.E., it can be used to discriminate P.E., even in the case of radiological opacity, from other unilateral disease inducing perfusion defect.

  7. Impact of ventilation/perfusion single-photon emission computed tomography on treatment duration of pulmonary embolism

    PubMed Central

    Begic, Amela; Opankovi?, Emina; ?uki?, Vesna; Rustempaši?, Medzida; Baši?, Amila; Miniati, Massimo; Jögi, Jonas

    2015-01-01

    Purpose The aim of the study was to establish whether the duration of anticoagulant (AC) therapy can be tailored, on an objective basis, by using ventilation/perfusion single-photon emission computed tomography (V/P SPECT) and to assess the extent of residual perfusion defects over time. In particular, we addressed the following: (a) is the extent of perfusion recovery at 3 months of initial pulmonary embolism (PE) diagnosis a satisfactory criterion for deciding the duration of oral AC? (b) Is it safe to withdraw AC at 3 months if perfusion recovery is complete? Patients and methods Of 269 consecutive patients with suspected PE, 100 patients were diagnosed with PE using V/P SPECT. Sixty-seven patients with acute PE were followed up clinically and with V/P SPECT at 3 months. Sixty-four patients were subject to review and examination using V/P SPECT for a period of 6 months and 33 were followed up only clinically. Therapy was terminated after 3 months if perfusion was normalized, and patients were free of symptoms and the risk of hypercoagulability. Initial extension of PE did not have an impact on decision making. Results PE extension varied from 10 to 70% in the acute stage. After 3 months, complete resolution of PE was found in 48 patients. The treating pulmonologist decided to terminate therapy in 35 (73%) patients and to continue AC in 13 patients because of persistent risk factors. Six months later, at the second control stage, 53 patients had complete recovery of pulmonary perfusion. Eleven patients still had perfusion defects at 6 months. No recurrence was identified at 6 months in the 35 patients whose therapy was terminated after 3 months. No bleeding effects were observed in any of the patients during the 6-month follow-up. Conclusion This study shows that AC therapy can be tailored, on an objective basis, by using V/P SPECT. Normalization of perfusion at 3 months of initial PE diagnosis was a reliable indicator that AC could be safely withdrawn in patients who were without hypercoagulability risk. PMID:25321156

  8. Distribution of regional lung aeration and perfusion during conventional and noisy pressure support ventilation in experimental lung injury.

    PubMed

    Carvalho, Alysson R; Spieth, Peter M; Güldner, Andreas; Cuevas, Maximilano; Carvalho, Nadja C; Beda, Alessandro; Spieth, Stephanie; Stroczynski, Christian; Wiedemann, Bärbel; Koch, Thea; Pelosi, Paolo; de Abreu, Marcelo Gama

    2011-04-01

    In acute lung injury (ALI), pressure support ventilation (PSV) may improve oxygenation compared with pressure-controlled ventilation (PCV), and benefit from random variation of pressure support (noisy PSV). We investigated the effects of PCV, PSV, and noisy PSV on gas exchange as well as the distribution of lung aeration and perfusion in 12 pigs with ALI induced by saline lung lavage in supine position. After injury, animals were mechanically ventilated with PCV, PSV, and noisy PSV for 1 h/mode in random sequence. The driving pressure was set to a mean tidal volume of 6 ml/kg and positive end-expiratory pressure to 8 cmH?O in all modes. Functional variables were measured, and the distribution of lung aeration was determined by static and dynamic computed tomography (CT), whereas the distribution of pulmonary blood flow (PBF) was determined by intravenously administered fluorescent microspheres. PSV and noisy PSV improved oxygenation and reduced venous admixture compared with PCV. Mechanical ventilation with PSV and noisy PSV did not decrease nonaerated areas but led to a redistribution of PBF from dorsal to ventral lung regions and reduced tidal reaeration and hyperinflation compared with PCV. Noisy PSV further improved oxygenation and redistributed PBF from caudal to cranial lung regions compared with conventional PSV. We conclude that assisted ventilation with PSV and noisy PSV improves oxygenation compared with PCV through redistribution of PBF from dependent to nondependent zones without lung recruitment. Random variation of pressure support further redistributes PBF and improves oxygenation compared with conventional PSV. PMID:21270348

  9. [The ventilation-perfusion ratio, with special reference to muscular exercise].

    PubMed

    Morpurgo, M; Panuccio, P; Anzalone, M; Beulcke, G; Cresci, F; Marconi, G; Rampulla, C; Viroli, L

    1975-01-01

    The values of VA/Q obtained at rest in 12 normal subjects undergoing cardiac catheterization in a supine position were between 0.63 and 1.695, with a mean of 1.142 +/- 0.295. The VA/Q values obtained in another 10 healthy subjects tested in a sitting position with a rebreathing method for calculating Q. were somewhat less scattered (between 0.77 and 1.50), and also lower (mean 0.975 +/- 0.210). A highly significant correlation was demonstrated during muscular exercise on the bicycle ergometer (sitting position), both between oxygen consumption and alveolar ventilation and between oxygen consumption and cardiac output. However, since at various submaximal work loads cardiac output increased much less than alveolar ventilation, the overall VA/Q ratio showed a progressive increment with increasing oxygen consumption. PMID:1205046

  10. Artificial perfusion of the ponto-medullary region of cats. A method for separation of central and peripheral effects of chemical stimulation of ventilation.

    PubMed

    Berkenbosch, A; Heeringa, J; Olievier, C N; Kruyt, E W

    1979-08-01

    A technique is described by which the ponto-medullary region of anaesthetized cats is artificially perfused with their own blood in which the blood gas tensions are varied independently from gas exchange in the lung. Blood from a femoral artery is fed into a foamer and defoamer. After alteration of the blood gas tensions in this equilibrator it is pumped via a cannulated vertebral artery into the medulla oblongata, pons and cerebellum. In this way two separately perfused areas are obtained in which the blood gas tensions can be changed independently. The peripheral chemoreceptors are supplied with blood of the systemic circulation while the central chemoreceptors and respiratory integrating centres are artificially perfused. With this technique the contribution of the peripheral and central chemoreceptors to the total ventilation and their interaction can be assessed. In addition the method is also suitable for studying the effects of drugs on the central regulation of respiration and circulation. PMID:493755

  11. Low-probability ventilation-perfusion scintigrams: clinical outcomes in 99 patients

    SciTech Connect

    Lee, M.E.; Biello, D.R.; Kumar, B.; Siegel, B.A.

    1985-08-01

    To evaluate the reliability of low probability ventilation-perfursion (V-P) scintigrams in excluding pulmonary embolism (PE), the authors reviewed the clinical records of 99 consecutive patients whose V-P studies had been interpreted as indicative of a low probability of PE. None of the 99 patients were referred for pulmonary angiography. Seven of the hospitalized patients died during the index admission and seven additional hospitalized patients died 1-5 months after discharge from the hospital. None were thought clinically to have died as a result of PE, and autopsy disclosed no PE in two. Follow-up information was obtained for 69 surviving patients not treated with anticoagulants. None of these patients were thought clinically to have had PE during follow-up of a least 2 weeks duration (greater than 2 months in 93% and greater than 6 months in 75%). The results suggest that major short-term morbidity or death attributable to PE are quite infrequent in patients with low-probability V-P scintigrams.

  12. Ventilation.

    PubMed

    Turner, W A; Bearg, D W; Brennan, T

    1995-01-01

    This chapter begins with an overview of the history of ventilation guidelines, which has led to the guidelines that are in effect today. Of particular interest is the most recent return in the past 5 years to ventilation rates that more closely reflect a mean or average of the range of guidelines that have existed over the past century. OSHA's and the EPA's recognition of the need to operate ventilation systems in buildings in an accountable manner is also of note. Of even more interest is the resurgence of the concept of minimum mixing and once-through ventilation air that has been pursued in parts of Northern Europe for the past 10 years, and in a school that is being designed with this concept in New Hampshire. In addition, the design concept of equipping office buildings with low pressure drop high efficiency particle filtration to remove fine particles from all of the air that is supplied to the occupants is being used increasingly in the U.S. This chapter also presents an overview of the various types of ventilation systems found in homes and commercial office buildings and the common indoor air quality problems that may be associated with them. It also offers an overview of common HVAC evaluation techniques that can be used to determine if a ventilation system is performing in a manner that makes sense for the use of the space and the needs of the occupants. Are the occupants receiving a reasonable supply of outdoor air? Is the air that they receive of reasonable quality? Are obvious pollutants being exhausted? Ventilation systems have become extremely complex and more difficult to run and maintain over the past 40 years. This trend will continue to drive the need for professionally maintained HVAC equipment that is serviced and run by individuals who are accountable for the quality of the air that the system delivers. PMID:7792680

  13. CHARGE IMBALANCE

    SciTech Connect

    Clarke, John

    1980-09-01

    The purpose of this article is to review the theory of charge imbalance, and to discuss its relevance to a number of experimental situations. We introduce the concepts of quasiparticle charge and charge imbalance, and discuss the generation and detection of charge imbalance by tunneling. We describe the relaxation of the injected charge imbalance by inelastic scattering processes, and show how the Boltzmann equation can be solved to obtain the steady state quasiparticle distribution and the charge relaxation rate. Details are given of experiments to measure charge imbalance and the charge relaxation rate when inelastic scattering is the predominant relaxation mechanism. Experiments on and theories of other charge relaxation mechanisms are discussed, namely relaxation via elastic scattering in the presence of energy gap anisotropy, or in the presence of a pair breaking mechanism such as magnetic impurities or an applied supercurrent or magnetic field. We describe three other situations in which charge imbalance occurs, namely the resistance of the NS interface, phase slip centers, and the flow of a supercurrent in the presence of a temperature gradient.

  14. Changes in Global Function and Regional Ventilation and Perfusion on SPECT During the Course of Radiotherapy in Patients With Non-Small-Cell Lung Cancer

    SciTech Connect

    Yuan Shuanghu; Frey, Kirk A.; Gross, Milton D.; Hayman, James A.; Arenberg, Doug; Cai Xuwei; Ramnath, Nithya; Hassan, Khaled; Moran, Jean; Eisbruch, Avraham; Ten Haken, Randall K.; Kong Fengming

    2012-03-15

    Purpose: This study aimed to (1) examine changes in dyspnea, global pulmonary function test (PFT) results, and functional activity on ventilation (V)/perfusion (Q) single-photon emission computerized tomography (SPECT) scans during the course of radiation (RT), and (2) factors associated with the changes in patients with non-small-cell lung cancer (NSCLC). Methods and Materials: Fifty-six stage I to III NSCLC patients treated with definitive RT with or without chemotherapy were enrolled prospectively. Dyspnea was graded according to Common Terminology Criteria for Adverse Events version 3.0 prior to and weekly during RT. V/Q SPECT-computed tomography (CT) and PFTs were performed prior to and during RT at approximately 45 Gy. Functions of V and Q activities were assessed using a semiquantitative scoring of SPECT images. Results: Breathing improved significantly at the third week (mean dyspnea grade, 0.8 vs. 0.6; paired t-test p = 0.011) and worsened during the later course of RT (p > 0.05). Global PFT results did not change significantly, while regional lung function on V/Q SPECT improved significantly after {approx}45 Gy. The V defect score (DS) was 4.9 pre-RT versus 4.3 during RT (p = 0.01); Q DS was 4.3 pre-RT versus 4.0 during RT (p < 0.01). Improvements in V and Q functions were seen primarily in the ipsilateral lung (V DS, 1.9 pre-RT versus 1.4 during RT, p < 0.01; Q DS, 1.7 pre-RT versus 1.5 during RT, p < 0.01). Baseline primary tumor volume was significantly correlated with pre-RT V/Q DS (p < 0.01). Patients with central lung tumors had greater interval changes in V and Q than those with more peripheral tumors (p <0.05 for both V and Q DS). Conclusions: Regional ventilation and perfusion improved during RT at 45 Gy. This suggests that adaptive planning based on V/Q SPECT during RT may allow sparing of functionally recoverable lung tissue.

  15. An evaluation of preoperative and postoperative ventilation and perfusion lung scintigraphy in the screening for pulmonary embolism after elective orthopedic surgery

    SciTech Connect

    Keenan, A.M.; Palevsky, H.I.; Steinberg, M.E.; Hartman, K.M.; Alavi, A.; Lotke, P.A. )

    1991-01-01

    One hundred two patients undergoing elective knee or hip arthroplasty were studied with radionuclide ventilation scans (V) and perfusion scans (Q) preoperatively (preop) and postoperatively (postop) to assess their relative value in the diagnosis of asymptomatic pulmonary embolism (PE) after orthopedic surgery. Postop Q were read in combination with preop V and Q and postop V using prospective investigation of pulmonary embolism diagnosis (PIOPED) criteria. Of 25 postop Q interpreted as either high or intermediate probability for PE, preop Q were judged useful in 96%; the postop V were useful in 78%; and the preop V were not helpful in any of the cases. Of 63 postop Q interpreted as low probability, preop Q were useful in 74%; the postop V were useful in only 33%; and the preop V were useful in only one case. When postop Q were read as normal (14 cases), none of the three auxiliary studies were found to be useful. Overall, postop V were more helpful than preop Q in only 2%, and preop V contributed significantly in only 1%. This experience suggests that preop Q alone is the most useful adjunct to the postop Q in the postoperative evaluation for PE. The authors conclude that to screen for asymptomatic PE after elective orthopedic surgery, preop Q should be performed in all cases, preop V are not necessary, and postop V need be performed only if a baseline preop Q is not available.

  16. The isolated perfused lung.

    PubMed Central

    Niemeier, R W

    1984-01-01

    The unique nonrespiratory functions of the lungs have become more apparent in recent years. The isolated perfused lung model offers many advantages over other methods for the study of pulmonary metabolism, xenobiotic disposition and the influence of interactions among agents of different physical forms. Detailed descriptions of the experimental preparation are elements in evaluating and comparing data from various sources but these are frequently neglected. A discussion and critique of the following elements are provided in this review in order to elucidate the typical problems one might encounter in evaluating data: perfusate type, perfusion method, construction materials, ventilation method, temperature control, surgical procedure, microbiological contamination and evaluation criteria of the preparation. Examples are given where the IPL method has been applied and suggestions are made for future research efforts. PMID:6383800

  17. The added value of hybrid ventilation/perfusion SPECT/CT in patients with stable COPD or apparently healthy smokers. Cancer-suspected CT findings in the lungs are common when hybrid imaging is used

    PubMed Central

    Jögi, Jonas; Markstad, Hanna; Tufvesson, Ellen; Bjermer, Leif; Bajc, Marika

    2015-01-01

    Ventilation/perfusion (V/P) single-photon emission computed tomography (SPECT) is recognized as a diagnostic method with potential beyond the diagnosis of pulmonary embolism. V/P SPECT identifies functional impairment in diseases such as heart failure (HF), pneumonia, and chronic obstructive pulmonary disease (COPD). The development of hybrid SPECT/computed tomography (CT) systems, combining functional with morphological imaging through the addition of low-dose CT (LDCT), may be useful in COPD, as these patients are prone to lung cancer and other comorbidities. The aim of this study was to investigate the added value of LDCT among healthy smokers and patients with stable COPD, when examined with V/P SPECT/CT hybrid imaging. Sixty-nine subjects, 55 with COPD (GOLD I–IV) and 14 apparently healthy smokers, were examined with V/P SPECT and LDCT hybrid imaging. Spirometry was used to verify COPD grade. Only one apparently healthy smoker and three COPD patients had a normal or nearly normal V/P SPECT. All other patients showed various degrees of airway obstruction, even when spirometry was normal. The same interpretation was reached on both modalities in 39% of the patients. LDCT made V/P SPECT interpretation more certain in 9% of the patients and, in 52%, LDCT provided additional diagnoses. LDCT better characterized the type of emphysema in 12 patients. In 19 cases, tumor-suspected changes were reported. Three of these 19 patients (ie, 4.3% of all subjects) were in the end confirmed to have lung cancer. The majority of LDCT findings were not regarded as clinically significant. V/P SPECT identified perfusion patterns consistent with decompensated left ventricular HF in 14 COPD patients. In 16 patients (23%), perfusion defects were observed. HF and perfusion defects were not recognized with LDCT. In COPD patients and long-time smokers, hybrid imaging had added value compared to V/P SPECT alone, by identifying patients with lung malignancy and more clearly identifying emphysema. V/P SPECT visualizes comorbidities to COPD not seen with LDCT, such as pulmonary embolism and left ventricular HF. PMID:25565797

  18. Ventilation and ventilators.

    PubMed

    Hayes, B

    1982-01-01

    The history of ventilation is reviewed briefly and recent developments in techniques of ventilation are discussed. Operating features of ventilators have changed in the past few years, partly as the result of clinical progress; yet, technology appears to have outstripped the clinician's ability to harness it most effectively. Clinical discipline and training of medical staff in the use of ventilators could be improved. The future is promising if clinician and designer can work together closely. Ergonomics of ventilators and their controls and the provision of alarms need special attention. Microprocessors are likely to feature prominently in the next generation of designs. PMID:6754938

  19. An improved setup for the isolated perfused rat lung.

    PubMed

    Uhlig, S; Wollin, L

    1994-04-01

    This article will describe a method for perfusing and ventilating rat lungs which allows assessment of lung mechanics, segmental vascular resistance, gas exchange, and vascular permeability. Isolated perfused rat lungs (IPL) were ventilated by negative pressure ventilation and were perfused at constant pressure with recirculating, albumin-containing Krebs-Henseleit buffer. A newly constructed respirator pump facilitated well-defined ventilation of the lungs and permitted switching between negative and positive pressure ventilation. Using this setup lungs were ventilated with positive pressure during both surgery and measurement of lung weight. Once the lungs were prepared, electronic control circuits ensured stability of the perfusate pH and perfusate pressure. Such preparations were stable for at least 3 hr. Breathing mechanics, for example, tidal volume, pulmonary compliance, and pulmonary resistance, perfusate characteristics, such as pulmonary vascular resistance, pulmonary pre- and postcapillary resistance, perfusate pH, PO2, and PCO2, and the capillary filtration coefficient were determined. All measured parameters were within normal physiological range, and the lungs were biochemically active, and responded to various stimuli. PMID:8032099

  20. Earth's Energy Imbalance

    NASA Astrophysics Data System (ADS)

    Trenberth, K. E.; Fasullo, J.

    2013-12-01

    'Global warming' from increased greenhouse gases really refers to a global energy imbalance at the top-of-atmosphere (TOA). TOA measurements of radiation from space can track changes over time but lack absolute accuracy. An inventory of energy shows that over 90% of the imbalance is manifested as ocean heat content (OHC). Here we use ORAS4 ocean reanalysis data and other OHC estimates to compare the OHC rates of change with model-based estimates of TOA energy imbalance (from CCSM4), and with TOA satellite measurements for the year 2000 onwards. Most of the ocean-only OHC analyses extend to only 700 m depth, have large discrepancies among the rates of change of OHC, and do not resolve interannual variability adequately to capture ENSO and volcanic eruption effects. For the first time we show that ORAS4 OHC quantitatively agrees with the radiative forcing estimates of impacts of the 3 major volcanic eruptions since 1960 (Mt. Agung 1963, El Chichón 1982, and Mt. Pinatubo 1991). The natural variability of the energy imbalance is substantial from month-to-month associated with cloud and weather variations, and interannually mainly associated with ENSO, while the sun affects 15% of the climate change signal on decadal timescales. All estimates (OHC and TOA) show that over the past decade the energy imbalance ranges between about 0.5 and 1 W m-2. By using the full-depth ocean, there is a better overall accounting for energy, but discrepancies remain at interannual timescales between OHC and TOA radiation measurements, notably in 2008-09.

  1. Ex vivo lung perfusion

    PubMed Central

    Machuca, Tiago N.

    2014-01-01

    Lung transplantation (LTx) is an established treatment option for eligible patients with end-stage lung disease. Nevertheless, the imbalance between suitable donor lungs available and the increasing number of patients considered for LTx reflects in considerable waitlist mortality. Among potential alternatives to address this issue, ex vivo lung perfusion (EVLP) has emerged as a modern preservation technique that allows for more accurate lung assessment and also improvement of lung function. Its application in high-risk donor lungs has been successful and resulted in safe expansion of the donor pool. This article will: (I) review the technical details of EVLP; (II) the rationale behind the method; (III) report the worldwide clinical experience with the EVLP, including the Toronto technique and others; (IV) finally, discuss the growing literature on EVLP application for donation after cardiac death (DCD) lungs. PMID:25132972

  2. Krypton-81m ventilation scanning: acute respiratory disease

    SciTech Connect

    Lavender, J.P.; Irving, H.; Armstrong, J.D. II

    1981-02-01

    From experience with 700 patients undergoing ventilation and perfusion lung scanning with krypton-81m/technetium-99m technique, 34 patients suffering from nonembolic acute respiratory disease were selected for review. In 16 patients with pneumonia, all had defects of ventilation corresponding to, or larger than, the radiologic consolidation. In 13 patients there was some preservation of perfusion in the consolidated region. In two of the three patients with matched defects, the pneumonia was of long standing. In seven patients with collapse or atelectasis and in 11 patients with acute reversible bronchial obstruction and normal volume lungs, a similar pattern or ventillation and perfusion was observed.

  3. Ventilative cooling

    E-print Network

    Graça, Guilherme Carrilho da, 1972-

    1999-01-01

    This thesis evaluates the performance of daytime and nighttime passive ventilation cooling strategies for Beijing, Shanghai and Tokyo. A new simulation method for cross-ventilated wind driven airflow is presented . This ...

  4. Functional Lung MRI in Chronic Obstructive Pulmonary Disease: Comparison of T1 Mapping, Oxygen-Enhanced T1 Mapping and Dynamic Contrast Enhanced Perfusion

    PubMed Central

    Jobst, Bertram J.; Triphan, Simon M. F.; Sedlaczek, Oliver; Anjorin, Angela; Kauczor, Hans Ulrich; Biederer, Jürgen; Ley-Zaporozhan, Julia; Ley, Sebastian; Wielpütz, Mark O.

    2015-01-01

    Purpose Monitoring of regional lung function in interventional COPD trials requires alternative endpoints beyond global parameters such as FEV1. T1 relaxation times of the lung might allow to draw conclusions on tissue composition, blood volume and oxygen fraction. The aim of this study was to evaluate the potential value of lung Magnetic resonance imaging (MRI) with native and oxygen-enhanced T1 mapping for the assessment of COPD patients in comparison with contrast enhanced perfusion MRI. Materials and Methods 20 COPD patients (GOLD I-IV) underwent a coronal 2-dimensional inversion recovery snapshot flash sequence (8 slices/lung) at room air and during inhalation of pure oxygen, as well as dynamic contrast-enhanced first-pass perfusion imaging. Regional distribution of T1 at room air (T1), oxygen-induced T1 shortening (?T1) and peak enhancement were rated by 2 chest radiologists in consensus using a semi-quantitative 3-point scale in a zone-based approach. Results Abnormal T1 and ?T1 were highly prevalent in the patient cohort. T1 and ?T1 correlated positively with perfusion abnormalities (r = 0.81 and r = 0.80; p&0.001), and with each other (r = 0.80; p<0.001). In GOLD stages I and II ?T1 was normal in 16/29 lung zones with mildly abnormal perfusion (15/16 with abnormal T1). The extent of T1 (r = 0.45; p<0.05), ?T1 (r = 0.52; p<0.05) and perfusion abnormalities (r = 0.52; p<0.05) showed a moderate correlation with GOLD stage. Conclusion Native and oxygen-enhanced T1 mapping correlated with lung perfusion deficits and severity of COPD. Under the assumption that T1 at room air correlates with the regional pulmonary blood pool and that oxygen-enhanced T1 reflects lung ventilation, both techniques in combination are principally suitable to characterize ventilation-perfusion imbalance. This appears valuable for the assessment of regional lung characteristics in COPD trials without administration of i.v. contrast. PMID:25822195

  5. Industrial ventilation

    NASA Astrophysics Data System (ADS)

    Goodfellow, H. D.

    Industrial ventilation design methodology, using computers and using fluid dynamic models, is considered. It is noted that the design of a ventilation system must be incorporated into the plant design and layout at the earliest conceptual stage of the project. A checklist of activities concerning the methodology for the design of a ventilation system for a new facility is given. A flow diagram of the computer ventilation model shows a typical input, the initialization and iteration loop, and the output. The application of the fluid dynamic modeling techniques include external and internal flow fields, and individual sources of heat and contaminants. Major activities for a ventilation field test program are also addressed.

  6. Ventilation Model

    SciTech Connect

    H. Yang

    1999-11-04

    The purpose of this analysis and model report (AMR) for the Ventilation Model is to analyze the effects of pre-closure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts and provide heat removal data to support EBS design. It will also provide input data (initial conditions, and time varying boundary conditions) for the EBS post-closure performance assessment and the EBS Water Distribution and Removal Process Model. The objective of the analysis is to develop, describe, and apply calculation methods and models that can be used to predict thermal conditions within emplacement drifts under forced ventilation during the pre-closure period. The scope of this analysis includes: (1) Provide a general description of effects and heat transfer process of emplacement drift ventilation. (2) Develop a modeling approach to simulate the impacts of pre-closure ventilation on the thermal conditions in emplacement drifts. (3) Identify and document inputs to be used for modeling emplacement ventilation. (4) Perform calculations of temperatures and heat removal in the emplacement drift. (5) Address general considerations of the effect of water/moisture removal by ventilation on the repository thermal conditions. The numerical modeling in this document will be limited to heat-only modeling and calculations. Only a preliminary assessment of the heat/moisture ventilation effects and modeling method will be performed in this revision. Modeling of moisture effects on heat removal and emplacement drift temperature may be performed in the future.

  7. Perfusion lung scan: an aid in detection of lymphangitic carcinomatosis

    SciTech Connect

    Bates, S.E.; Tranum, B.L.

    1982-07-15

    Lymphangitic carcinomatosis is usually a late manifestation of metastatic disease. The patient usually presents with cough or dyspnea, and the chest radiograph is often nondiagnostic. Two patients are presented who developed symptoms while on adjuvant chemotherapy. Both had abnormal perfusion lung scans. One had matching ventilation defects; the other a normal ventilation study. Biopsy revealed metastatic carcinoma; in one case tumor was seen in both the pulmonary lymphatics and arterioles; in technique which can speed diagnosis and institution of therapy in lymphangitic carcinomatosis.

  8. Ventilation Model

    SciTech Connect

    V. Chipman

    2002-10-05

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. The purposes of Revision 01 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to initialize post-closure thermal models (Section 6.6). (3) To satisfy the remainder of KTI agreement TEF 2.07 (Reamer and Williams 2001b). Specifically to provide the results of post-test ANSYS modeling of the Atlas Facility forced convection tests (Section 7.1.2). This portion of the model report also serves as a validation exercise per AP-SIII.10Q, Models, for the ANSYS ventilation model. (4) To further satisfy KTI agreements RDTME 3.01 and 3.14 (Reamer and Williams 2001a) by providing the source documentation referred to in the KTI Letter Report, ''Effect of Forced Ventilation on Thermal-Hydrologic Conditions in the Engineered Barrier System and Near Field Environment'' (Williams 2002). Specifically to provide the results of the MULTIFLUX model which simulates the coupled processes of heat and mass transfer in and around waste emplacement drifts during periods of forced ventilation. This portion of the model report is presented as an Alternative Conceptual Model with a numerical application, and also provides corroborative results used for model validation purposes (Section 6.3 and 6.4).

  9. Liquid ventilation.

    PubMed

    Sarkar, Suman; Paswan, Anil; Prakas, S

    2014-01-01

    Human have lungs to breathe air and they have no gills to breath liquids like fish. When the surface tension at the air-liquid interface of the lung increases as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV) is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen as the inert carrier of oxygen and carbon dioxide offers a number of advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. It is well-known that respiratory diseases are one of the most common causes of morbidity and mortality in intensive care unit. During the past few years several new modalities of treatment have been introduced. One of them and probably the most fascinating, is of LV. Partial LV, on which much of the existing research has concentrated, requires partial filling of lungs with perfluorocarbons (PFC's) and ventilation with gas tidal volumes using conventional mechanical ventilators. Various physico-chemical properties of PFC's make them the ideal media. It results in a dramatic improvement in lung compliance and oxygenation and decline in mean airway pressure and oxygen requirements. No long-term side-effect reported. PMID:25886321

  10. Pulmonary blood flow distribution in sheep: effects of anesthesia, mechanical ventilation, and change in posture

    NASA Technical Reports Server (NTRS)

    Walther, S. M.; Domino, K. B.; Glenny, R. W.; Hlastala, M. P.

    1997-01-01

    BACKGROUND: Recent studies providing high-resolution images of pulmonary perfusion have questioned the classical zone model of pulmonary perfusion. Hence the present work was undertaken to provide detailed maps of regional pulmonary perfusion to examine the influence of anesthesia, mechanical ventilation, and posture. METHODS: Pulmonary perfusion was analyzed with intravenous fluorescent microspheres (15 microm) in six sheep studied in four conditions: prone and awake, prone with pentobarbital-anesthesia and breathing spontaneously, prone with anesthesia and mechanical ventilation, and supine with anesthesia and mechanical ventilation. Lungs were air dried at total lung capacity and sectioned into approximately 1,100 pieces (about 2 cm3) per animal. The pieces were weighed and assigned spatial coordinates. Fluorescence was read on a spectrophotometer, and signals were corrected for piece weight and normalized to mean flow. Pulmonary blood flow heterogeneity was assessed using the coefficient of variation of flow data. RESULTS: Pentobarbital anesthesia and mechanical ventilation did not influence perfusion heterogeneity, but heterogeneity increased when the animals were in the supine posture (P < 0.01). Gravitational flow gradients were absent in the prone position but present in the supine (P < 0.001 compared with zero). Pulmonary perfusion was distributed with a hilar-to-peripheral gradient in animals breathing spontaneously (P < 0.05). CONCLUSIONS: The influence of pentobarbital anesthesia and mechanical ventilation on pulmonary perfusion heterogeneity is small compared with the effect of changes in posture. Analysis of flow gradients indicate that gravity plays a small role in determining pulmonary blood flow distribution.

  11. Ventilator waveforms.

    PubMed

    Mellema, Matthew S

    2013-08-01

    Ventilator waveforms are graphic representations of changes in pressure, flow, and volume within a ventilator circuit. The changes in these parameters over time may be displayed individually (scalars) or plotted one against another (pressure-volume and flow-volume loops). There are 6 basic shapes of scalar waveforms, but only 3 are functionally distinct (square, ramp, and sine). The pressure scalar is a particularly valuable tool when constant flow (e.g., volume control) modes are employed and an inspiratory pause is added. In this setting, inspection of the pressure waveform can allow determination of static, quasistatic, and dynamic compliance, as well as relative changes in airway resistance. Inspection of the pressure waveform can also help to identify many important aspects of patient drug responses, dyssynchrony, and air trapping (auto positive end-expiratory pressure [auto-PEEP]). Depending on the ventilation mode employed, the shape of the flow waveform may be set by the ventilator operator or may be dependent on patient effort and lung mechanics. Decelerating flow patterns have several important advantages when this option is available. Inspection of flow waveforms is crucial in the recognition of dyssynchrony, setting optimal inspiratory times, evaluating responses to bronchodilators, and the recognition of auto-PEEP. The volume waveform often contains somewhat less useful information than the other 2 scalars, but plays a crucial role in the identification of leaks in the circuit. Pressure-volume loops are particularly useful in setting PEEP and peak inspiratory pressure ranges. Inspection of these loops also often helps in the evaluation of lung mechanics, in the identification of circuit leaks, and in the assessment of patient triggering effort. Flow-volume loops are extremely useful in the identification of leaks and excessive airway secretions as well as alterations in airway resistance. Lastly, serial waveform inspection is crucial to the identification and resolution of patient-ventilator dyssynchrony in many cases. PMID:24183000

  12. Single perfusion defect and pulmonary embolism: Angiographic correlation

    SciTech Connect

    Catania, T.A.; Caride, V.J. )

    1990-03-01

    One hundred and thirty-three ventilation-perfusion scans (V-P) with angiographic correlation were retrospectively reviewed to evaluate the frequency of pulmonary emboli (PE) in single perfusion defects (SPD), regardless of ventilation or radiographic findings. By angiography, 15 of 30 SPD cases had PE. Demographic data and clinical presentation were similar for PE and non-PE patients. However, 9 out of 15 patients with PE had recent surgery compared to none of the non-PE patients. SPD were seen in areas of ventilation and chest x-ray abnormalities in 12 of 15 PE and 11 of 19 non-PE cases. Size of the actual lesion was underestimated by scintigraphy in most cases. In 7 of 15 PE cases, the perfusion defect was larger than the corresponding ventilation abnormality. Most SPD were located at the bases. Twelve of 15 SPD in the PE group were at the posterior basilar segment. In the appropriate clinical setting, SPD carries at least a moderate probability for PE. When the clinical suspicion is high, a pulmonary angiography will be needed to confirm the diagnosis.

  13. Oxidative Imbalance and Anxiety Disorders

    PubMed Central

    R, Krolow; D. M, Arcego; C, Noschang; S. N, Weis; C, Dalmaz

    2014-01-01

    The oxidative imbalance appears to have an important role in anxiety development. Studies in both humans and animals have shown a strong correlation between anxiety and oxidative stress. In humans, for example, the increased malondialdehyde levels and discrepancies in antioxidant enzymes in erythrocytes have been observed. In animals, several studies also show that anxiety-like behavior is related to the oxidative imbalance. Moreover, anxiety-like behavior can be caused by pharmacological-induced oxidative stress. Studies using knockout or overexpression of antioxidant enzymes have shown a relationship between anxiety-like behavior and oxidative stress. Related factors of oxidative stress that could influence anxious behavior are revised, including impaired function of different mitochondrial proteins, inflammatory cytokines, and neurotrophic factors. It has been suggested that a therapy specifically focus in reducing reactive species production may have a beneficial effect in reducing anxiety. However, the neurobiological pathways underlying the effect of oxidative stress on anxiety symptoms are not fully comprehended. The challenge now is to identify the oxidative stress mechanisms likely to be involved in the induction of anxiety symptoms. Understanding these pathways could help to clarify the neurobiology of the anxiety disorder and provide tools for new discovery in therapies and preventive strategies. PMID:24669212

  14. Gas exchange and intrapulmonary distribution of ventilation during continuous-flow ventilation

    SciTech Connect

    Vettermann, J.; Brusasco, V.; Rehder, K.

    1988-05-01

    In 12 anesthetized paralyzed dogs, pulmonary gas exchange and intrapulmonary inspired gas distribution were compared between continuous-flow ventilation (CFV) and conventional mechanical ventilation (CMV). Nine dogs were studied while they were lying supine, and three dogs were studied while they were lying prone. A single-lumen catheter for tracheal insufflation and a double-lumen catheter for bilateral endobronchial insufflation (inspired O2 fraction = 0.4; inspired minute ventilation = 1.7 +/- 0.3 (SD) 1.kg-1.min-1) were evaluated. Intrapulmonary gas distribution was assessed from regional 133Xe clearances. In dogs lying supine, CO2 elimination was more efficient with endobronchial insufflation than with tracheal insufflation, but the alveolar-arterial O2 partial pressure difference was larger during CFV than during CMV, regardless of the type of insufflation. By contrast, endobronchial insufflation maintained both arterial PCO2 and alveolar-arterial O2 partial pressure difference at significantly lower levels in dogs lying prone than in dogs lying supine. In dogs lying supine, the dependent lung was preferentially ventilated during CMV but not during CFV. In dogs lying prone, gas distribution was uniform with both modes of ventilation. The alveolar-arterial O2 partial pressure difference during CFV in dogs lying supine was negatively correlated with the reduced ventilation of the dependent lung, which suggests that increased ventilation-perfusion mismatching was responsible for the increase in alveolar-arterial O2 partial pressure difference. The more efficient oxygenation during CFV in dogs lying prone suggests a more efficient matching of ventilation to perfusion, presumably because the distribution of blood flow is also nearly uniform.

  15. Estimation of Lung Ventilation

    NASA Astrophysics Data System (ADS)

    Ding, Kai; Cao, Kunlin; Du, Kaifang; Amelon, Ryan; Christensen, Gary E.; Raghavan, Madhavan; Reinhardt, Joseph M.

    Since the primary function of the lung is gas exchange, ventilation can be interpreted as an index of lung function in addition to perfusion. Injury and disease processes can alter lung function on a global and/or a local level. MDCT can be used to acquire multiple static breath-hold CT images of the lung taken at different lung volumes, or with proper respiratory control, 4DCT images of the lung reconstructed at different respiratory phases. Image registration can be applied to this data to estimate a deformation field that transforms the lung from one volume configuration to the other. This deformation field can be analyzed to estimate local lung tissue expansion, calculate voxel-by-voxel intensity change, and make biomechanical measurements. The physiologic significance of the registration-based measures of respiratory function can be established by comparing to more conventional measurements, such as nuclear medicine or contrast wash-in/wash-out studies with CT or MR. An important emerging application of these methods is the detection of pulmonary function change in subjects undergoing radiation therapy (RT) for lung cancer. During RT, treatment is commonly limited to sub-therapeutic doses due to unintended toxicity to normal lung tissue. Measurement of pulmonary function may be useful as a planning tool during RT planning, may be useful for tracking the progression of toxicity to nearby normal tissue during RT, and can be used to evaluate the effectiveness of a treatment post-therapy. This chapter reviews the basic measures to estimate regional ventilation from image registration of CT images, the comparison of them to the existing golden standard and the application in radiation therapy.

  16. What is Imbalance of Nature?

    NASA Astrophysics Data System (ADS)

    Kontar, V. A.

    2012-12-01

    The Mother Nature is imbalanced at all. The Mother Nature is every moment new, never returns to previous condition. The gravity and magnetosphere are changeable and imbalanced. The Sun is changeable and imbalanced. The climate is changeable and imbalanced. The atmosphere is changeable and imbalanced. The ocean is changeable and imbalanced. The crust and deep interior are changeable and imbalanced. The cryosphere is changeable and imbalanced. The life is simultaneously as the creator and the result of the imbalance of Nature. The people society is changeable and imbalanced. All chemical, physical, social, and other phenomenons are changeable and imbalanced. It's just that each phenomenon of the Mother Nature has some personal time-scale: one change in a nanosecond, and looks like for us as instable, i.e. imbalanced; while others change over millions years and, therefore, to us looks like not changeable, i.e. balanced. The scientists who are studying the Nature have convinced that the real balance never exist in Nature. Sometimes we can see something that is stable, i.e. balanced. But on closer study it appears that we are witnessing is not eternal rest and balance, it is not eternal STOP, but it is the perpetual motion, changing, there are a lot of imbalances. The balance it can be some result of the temporary mutual compensation the imbalanced processes in opposite directions. The balance it can be also some result of the inaccurate measurement, misunderstanding of conception or even request from bosses. But if we start use more accurate measurements, improve the models and not fear the bosses, than usually we got some new details. These new details show thet under the balanced visibility in really is hiding the interaction of many imbalanced processes of different directions. The balanced logic usually answers to question: What is it? The balanced answers are approximate and it will be updated many times during the development of science and practice. The imbalanced logic usually answers to question: How and why it is happened in details? The imbalanced answers are approximate also, and they will also be updated many times during the development of science and practice. But the imbalanced logic allows us to overcome of the inertia of the balanced logic and much closer come up to understanding the essence of Nature. We try to answer the central question of humanity: How to get calm, i.e. balanced life if the everything around us is imbalanced, the people themselves are restless and not eternal? The study of the Imbalance of Nature is multi-disciplinary because Nature is one. It is our main advantage.

  17. Energy Imbalance Markets (Fact Sheet)

    SciTech Connect

    Not Available

    2012-09-01

    The anticipated increase in variable renewable generation, such as wind and solar power, over the next several years has raised concerns about how system operators will maintain balance between electricity production and demand in the Western Interconnection, especially in its smaller balancing authority areas (BAAs). Given renewable portfolio standards in the West, it is possible that more than 50 gigawatts of wind capacity will be installed by 2020. Significant quantities of solar generation are likely to be added as well. Meanwhile, uncertainties about future load growth and challenges siting new transmission and generation resources may add additional stresses on the Western Interconnection of the future. One proposed method of addressing these challenges is an energy imbalance market (EIM). An EIM is a means of supplying and dispatching electricity to balance fluctuations in generation and load. It aggregates the variability of generation and load over multiple balancing areas (BAs).

  18. Perfusion lung scan: an aid in detection of lymphangitic carcinomatosis

    SciTech Connect

    Bates, S.E.; Tranum, B.L.

    1982-07-15

    Lymphangitic carcinomatosis is usually a late manifestation of metastatic disease. The patient usually presents with cough or dyspnea, and the chest radiograph is often nondiagnostic. Two patients are presented who developed symptoms while on adjuvant chemotherapy. Both had abnormal perfusion lung scans. One had matching ventilation defects; the other a normal ventilation study. Biopsy revealed metastatic carcinoma; in one case tumor was seen in both the pulmonary lymphatics and arterioles; in the other, tumor was identified but the site could not be specified. The radionuclide lung scan is a technique which can speed diagnosis and institution of therapy in lymphangitic carcinomatosis.

  19. Abdominal perfusion computed tomography.

    PubMed

    Ogul, Hayri; Bayraktutan, Ummugulsum; Kizrak, Yesim; Pirimoglu, Berhan; Yuceler, Zeynep; Sagsoz, M Erdem; Yilmaz, Omer; Aydinli, Bulent; Ozturk, Gurkan; Kantarci, Mecit

    2013-02-01

    The purpose of this article is to provide an up to date review on the spectrum of applications of perfusion computed tomography (CT) in the abdomen. New imaging techniques have been developed with the objective of obtaining a structural and functional analysis of different organs. Recently, perfusion CT has aroused the interest of many researchers who are studying the applicability of imaging modalities in the evaluation of abdominal organs and diseases. Per-fusion CT enables fast, non-invasive imaging of the tumor vascular physiology. Moreover, it can act as an in vivo biomarker of tumor-related angiogenesis. PMID:25610249

  20. Abdominal Perfusion Computed Tomography

    PubMed Central

    Ogul, Hayri; Bayraktutan, Ummugulsum; Kizrak, Yesim; Pirimoglu, Berhan; Yuceler, Zeynep; Sagsoz, M. Erdem; Yilmaz, Omer; Aydinli, Bulent; Ozturk, Gurkan; Kantarci, Mecit

    2013-01-01

    The purpose of this article is to provide an up to date review on the spectrum of applications of perfusion computed tomography (CT) in the abdomen. New imaging techniques have been developed with the objective of obtaining a structural and functional analysis of different organs. Recently, perfusion CT has aroused the interest of many researchers who are studying the applicability of imaging modalities in the evaluation of abdominal organs and diseases. Per-fusion CT enables fast, non-invasive imaging of the tumor vascular physiology. Moreover, it can act as an in vivo biomarker of tumor-related angiogenesis. PMID:25610249

  1. Identifying acid-base and electrolyte imbalances.

    PubMed

    Gooch, Michael D

    2015-08-15

    Acid-base and electrolyte imbalances often complicate patient management in acute care settings. Correctly identifying the imbalance and its cause is vital. This article will review the physiology of acid-base and electrolyte balance, their common disturbances, associated causes, clinical manifestations, and management implications for nurse practitioners. PMID:26180912

  2. The surface energy imbalance problem

    NASA Astrophysics Data System (ADS)

    Leuning, R.; van Gorsel, E.; Massman, W.

    2012-04-01

    The 'energy imbalance problem' in micrometeorology arises because at most flux measurement sites the sum of eddy fluxes of sensible latent heat (H + ?E) is 50 - 200 W m-2 less than the available energy (A) at half-hourly time scales. Thus either eddy fluxes of H and ?Eare underestimated or A is overestimated. Lack of energy closure is caused by: 1) a failure to satisfy the fundamental assumption of one-dimensional transport needed for measurements on a single tower to represent spatially-averaged fluxes to/from the underlying surface; 2) measurement errors in: i) eddy fluxes, ii) net radiation, iii) changes in energy storage in soils, air, and biomass below the measurement height. Review of the literature shows that radiometric errors are unlikely to cause significant overestimates of A at all flux measurement sites, but phase lags between H + ?E and A caused by incorrect estimates of the energy storage terms that contribute to A can explain why H + ?E systematically underestimates A at half-hourly time scales. Energy closure is observed at only 8% of flux sites in the La Thuile dataset (http://www.fluxdata.org/DataInfo/default.aspx), with a median slope of 0.75 for H + ?E versus A for half-hourly averages. Using 24h averages leads to energy closure at 45% of the La Thuile sites, and the median slope of H + ?E versus A increases to 0.90. Increasing the averaging time reduces the bias in A because energy entering the soil, air and biomass in the morning is returned in the afternoon and evening. Unrealistically large positive horizontal temperature gradients of 4 - 10 °K km-1 are needed for horizontal advective flux divergences to explain the 50 - 200 W m-2 underestimate of H + ?E compared to A often observed at half-hourly time scales. Similarly, unrealistically large mean vertical velocities and temperature gradients are needed for vertical advective flux divergences to account for the 'missing' energy. Imbalances between H + ?E and A still occur in daily averages but the small residual energy imbalances are explicable by positive and negative horizontal and vertical advective flux divergences. Systematic underestimates of the vertical heat flux also occur if horizontal u'T'covariances contaminate the vertical w'T' signal due to incorrect coordinate rotations. An incorrect tilt angle of 2° will cause a 5% underestimate of H. Closure of the energy balance is possible at half-hourly time scales by careful selection of horizontally homogeneous sites to satisfy the assumptions of one-dimensional transport underpinning eddy covariance measurements on single towers , attention to all sources of measurement and data processing errors in the eddy covariance system, and by accurate measurement of net radiation and every energy storage term needed to calculate available energy.

  3. Earth's Energy Imbalance and Implications

    E-print Network

    Hansen, James; Kharecha, Pushker; von Schuckmann, Karina

    2011-01-01

    Improving observations of ocean temperature confirm that Earth is absorbing more energy from the sun than it is radiating to space as heat, even during the recent solar minimum. The inferred planetary energy imbalance, 0.59 \\pm 0.15 W/m2 during the 6-year period 2005-2010, provides fundamental verification of the dominant role of the human-made greenhouse effect in driving global climate change. Observed surface temperature change and ocean heat gain constrain the net climate forcing and ocean mixing rates. We conclude that most climate models mix heat too efficiently into the deep ocean and as a result underestimate the negative forcing by human-made aerosols. Aerosol climate forcing today is inferred to be -1.6 \\pm 0.3 W/m2, implying substantial aerosol indirect climate forcing via cloud changes. Continued failure to quantify the specific origins of this large forcing is untenable, as knowledge of changing aerosol effects is needed to understand future climate change. A recent decrease in ocean heat uptake ...

  4. VENTILATION NEEDS DURING CONSTRUCTION

    SciTech Connect

    C.R. Gorrell

    1998-07-23

    The purpose of this analysis is to determine ventilation needs during construction and development of the subsurface repository and develop systems to satisfy those needs. For this analysis, construction is defined as pre-emplacement excavation and development is excavation that takes place simultaneously with emplacement. The three options presented in the ''Overall Development and Emplacement Ventilation Systems'' analysis (Reference 5.5) for development ventilation will be applied to construction ventilation in this analysis as well as adding new and updated ventilation factors to each option for both construction and development. The objective of this analysis is to develop a preferred ventilation system to support License Application Design. The scope of this analysis includes: (1) Description of ventilation conditions; (2) Ventilation factors (fire hazards, dust control, construction logistics, and monitoring and control systems); (3) Local ventilation alternatives; (4) Global ventilation options; and (5) Evaluation of options.

  5. Nonperipheral chemoreceptor stimulation of ventilation by cyanide.

    PubMed

    Levine, S

    1975-08-01

    To assess the ventilatory responses elicited by changes of tissue hypoxia, sodium cyanide (0.12 mg/kg-min for 10 min) was infused into the upper abdominal aorta of anesthetized dogs. These infusions produced decreases in oxygen consumption, increases in arterial lactate concentration, and increases in arterial lactate/pyruvate ratio. Coincident with these metabolic changes of hypoxia, minute ventilation (VE) increased 228 +/- SE 36% and arterial PCO2 decreased 21 +/- SE 2 mmHg; therefore, pH increased both in arterial blood in and cisternal cerebrospinal fluid. Following infusion of cyanide into the abdominal aorta, small quantities of cyanide (48 +/- SE 14 mumol/liter) appeared in carotid arterial blood. To evaluate the possibility that the observed increases in VE were due to stimulation of peripheral arterial chemoreceptors by the recirculating cyanide, the carotid and aortic chemoreceptors were denervated in four dogs. Nonetheless, after intra-aortic infusion of sodium cyanide (1.2 mg/kg), ventilation in these chemodenervated animals again increased considerably (154 +/- SE 36%). In order to explore the possibility that cyanide infusion can stimulate ventilation by an extracranial mechanism, heads of vagotomized dogs (including the carotid bodies) were perfused entirely by donor dogs. The intra-aortic infusion of sodium cyanide (0.9 mg/kg) into these head-perfused animals still caused large increases in VE (163 +/- SE 19%). It is concluded that intra-aortic cyanide infusions stimulate VE by an extracranial mechanism other than the carotid and aortic chemoreceptors. PMID:240795

  6. A rational framework for selecting modes of ventilation.

    PubMed

    Mireles-Cabodevila, Eduardo; Hatipo?lu, Umur; Chatburn, Robert L

    2013-02-01

    Mechanical ventilation is a life-saving intervention for respiratory failure and thus has become the cornerstone of the practice of critical care medicine. A mechanical ventilation mode describes the predetermined pattern of patient-ventilator interaction. In recent years there has been a dizzying proliferation of mechanical ventilation modes, driven by technological advances and market pressures, rather than clinical data. The comparison of these modes is hampered by the sheer number of combinations that need to be tested against one another, as well as the lack of a coherent, logical nomenclature that accurately describes a mode. In this paper we propose a logical nomenclature for mechanical ventilation modes, akin to biological taxonomy. Accordingly, the control variable, breath sequence, and targeting schemes for the primary and secondary breaths represent the order, family, genus, and species, respectively, for the described mode. To distinguish unique operational algorithms, a fifth level of distinction, termed variety, is utilized. We posit that such coherent ordering would facilitate comparison and understanding of modes. Next we suggest that the clinical goals of mechanical ventilation may be simplified into 3 broad categories: provision of safe gas exchange; provision of comfort; and promotion of liberation from mechanical ventilation. Safety is achieved via optimization of ventilation-perfusion matching and pressure-volume relationship of the lungs. Comfort is provided by fostering patient-ventilator synchrony. Liberation is promoted by optimization of the weaning experience. Then we follow a paradigm that matches the technological capacity of a particular mode to achieving a specific clinical goal. Finally, we provide the reader with a comparison of existing modes based on these principles. The status quo in mechanical ventilation mode nomenclature impedes communication and comparison of existing mechanical ventilation modes. The proposed model, utilizing a systematic nomenclature, provides a useful framework to address this unmet need. PMID:22710796

  7. VENTILATION MODEL REPORT

    SciTech Connect

    V. Chipman

    2002-10-31

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses.

  8. VENTILATION TECHNOLOGY SYSTEMS ANALYSIS

    EPA Science Inventory

    The report gives results of a project to develop a systems analysis of ventilation technology and provide a state-of-the-art assessment of ventilation and indoor air quality (IAQ) research needs. (NOTE: Ventilation technology is defined as the hardware necessary to bring outdoor ...

  9. Contaminants in Naturally Ventilated

    E-print Network

    Politècnica de Catalunya, Universitat

    a natural ventilation/flushing Volcanic Magma Chambers Deep Ocean Recirculation Basins Lakes Buildings (My;Displacement Ventilation An air distribution system in which incoming air originates at floor level and risesContaminants in Naturally Ventilated Closed Spaces Diogo Bolster #12;Outline Motivation Modelling

  10. DEMAND CONTROLLED VENTILATION AND CLASSROOM VENTILATION

    SciTech Connect

    Fisk, William J.; Mendell, Mark J.; Davies, Molly; Eliseeva, Ekaterina; Faulkner, David; Hong, Tienzen; Sullivan, Douglas P.

    2014-01-06

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling. Major findings included: ? The single-location carbon dioxide sensors widely used for demand controlled ventilation frequently have large errors and will fail to effectively control ventilation rates (VRs).? Multi-location carbon dioxide measurement systems with more expensive sensors connected to multi-location sampling systems may measure carbon dioxide more accurately.? Currently-available optical people counting systems work well much of the time but have large counting errors in some situations. ? In meeting rooms, measurements of carbon dioxide at return-air grilles appear to be a better choice than wall-mounted sensors.? In California, demand controlled ventilation in general office spaces is projected to save significant energy and be cost effective only if typical VRs without demand controlled ventilation are very high relative to VRs in codes. Based on the research, several recommendations were developed for demand controlled ventilation specifications in the California Title 24 Building Energy Efficiency Standards.The research on classroom ventilation collected data over two years on California elementary school classrooms to investigate associations between VRs and student illness absence (IA). Major findings included: ? Median classroom VRs in all studied climate zones were below the California guideline, and 40percent lower in portable than permanent buildings.? Overall, one additional L/s per person of VR was associated with 1.6percent less IA. ? Increasing average VRs in California K-12 classrooms from the current average to the required level is estimated to decrease IA by 3.4percent, increasing State attendance-based funding to school districts by $33M, with $6.2 M in increased energy costs. Further VR increases would provide additional benefits.? Confirming these findings in intervention studies is recommended. ? Energy costs of heating/cooling unoccupied classrooms statewide are modest, but a large portion occurs in relatively few classrooms.

  11. Subsynchronous resonance countermeasure using phase imbalance

    SciTech Connect

    Edris, A. )

    1993-11-01

    Subsynchronous Resonance (SSR) in series compensated power systems is a phenomenon implying an undesirable energy exchange between the electrical and mechanical sides of turbine-generator sets, at a frequency below the power frequency (60 Hz in the USA). Since the discovery in 1970 that SSR was the main cause of the shaft failures at the Mohave plant in Southern Nevada, extensive research and development efforts have been devoted to the development of effective SSR mitigation measures. This paper presents a contribution to these efforts by providing a rather new concept for simple and reliable SSR mitigation. The basic idea is to reduce the energy exchange between the two sides of turbine-generator sets at subsynchronous oscillations by weakening the electromechanical coupling. This is attained by creating phase imbalance at subsynchronous oscillations. The imbalance diminishes the capability of the three phase currents to develop interacting electromagnetic torques and, therefore, suppresses energy exchange between the electrical and mechanical sides of turbine-generator sets. The basis of this idea have been presented by the author in a previous IEEE paper, where the phase imbalance was associated with the series capacitor banks. The objective of this paper is to study the influence of having the phase imbalance associated with the generator to be protected from potential torsional interaction problems.

  12. Ventilation Model Report

    SciTech Connect

    V. Chipman; J. Case

    2002-12-20

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. Revision 01 ICN 01 included the results of the unqualified software code MULTIFLUX to assess the influence of moisture on the ventilation efficiency. The purposes of Revision 02 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to initialize post-closure thermal models (Section 6.6). (3) To satisfy the remainder of KTI agreement TEF 2.07 (Reamer and Williams 2001b). Specifically to provide the results of post-test ANSYS modeling of the Atlas Facility forced convection tests (Section 7.1.2). This portion of the model report also serves as a validation exercise per AP-SIII.10Q, Models, for the ANSYS ventilation model. (4) To asses the impacts of moisture on the ventilation efficiency.

  13. Education in the imbalance of Nature

    NASA Astrophysics Data System (ADS)

    Shlafman, L. M.; Kontar, V. A.

    2013-12-01

    There are two concepts understanding of the real Nature: balanced and imbalanced. The traditional balanced concept understanding of Nature was originated in prehistoric times to calm the frightened souls of prehistoric man and manage groups of people. The balanced concept presupposes that Nature is isotropic, balanced, etc. The balanced concept of understanding of Nature gradually has moved to science and technology. The balanced concept of understanding of Nature is dominating from the prehistoric time up to today. But always parallel and opposite was exists the concept imbalanced understanding of Nature, which presupposes that Nature is anisotropy, imbalanced, etc. The balanced concept is much simpler than Imbalanced. The balanced concept has given mankind a lot of rough description of Nature which helped to solve a lot of practical problems but with sufficient accuracy, i.e. approximately, but not with an absolute precision. While people were few, and a lot of resources, person could take from Nature only what Nature gave willingly. During this period, people feared and respected Nature and Nature was able easily compensate the activity of people. The high accuracy of the description of Nature was not needed when resources were plentiful and people were few. But now the situation is completely different. The population has become a very large and growing. Traditional resources are almost run out and the lack of resources escalates. People are not afraid of Nature and bravely try to take by force what Nature does not give voluntarily. People invaded into imbalance Nature, and Nature can no longer compensate activity of people. The era of global change is started, including those that man provokes. In the conditions of global changes is insufficiently of the approximate solutions of the traditional balanced concept. The balanced concept is exhausted, and increasingly misleads people. The balanced concept cannot solve the problems that arise in the global change. The Concept imbalance of Nature is more suitable to solve problems of global change. Many thousands of scientists and practical from around the world are working already in the field of imbalance of Nature. Now is a time when the concept imbalance of Nature should be included into the training programs at universities, colleges and schools. We have experts who can teach students in imbalance of Nature. We have a list of topics for Ph.D. dissertations in field of imbalance of Nature. Now we are preparing the fundamental scientific book on all major issues imbalance of Nature. On the basis of this fundamental scientific work will be prepared the textbooks for students of different levels, non-fiction books, will organized promotion of the imbalance of Nature in the media, social networks, etc. People need to understand the real Nature as it is. This new knowledge will help humanity make the right and safer decisions in the era of global change. We invite the universities, colleges, schools, community organizations, sponsors and just responsible people of any country in the world to take part in this noble and vital issue. Humanity has no choice. Or mankind will have time to learn how to live in the era of global change or perish. The concept imbalance of Nature gives humanity the chance to survive.

  14. Prevention of Ventilator-Induced Lung Edema by Inhalation of Nanoparticles Releasing Ruthenium Red

    PubMed Central

    Jurek, Samuel C.; Hirano-Kobayashi, Mariko; Chiang, Homer; Kohane, Daniel S.

    2014-01-01

    The acute respiratory distress syndrome (ARDS), a devastating lung disease that has no cure, is exacerbated by life-supportive mechanical ventilation that worsens lung edema and inflammation through the syndrome of ventilator-induced lung injury. Recently, the membrane ion channel transient receptor potential vanilloid 4 (TRPV4) on alveolar macrophages was shown to mediate murine lung vascular permeability induced by high-pressure mechanical ventilation. The objective of this study was to determine whether inhalation of nanoparticles (NPs) containing the TRPV4 inhibitor ruthenium red (RR) prevents ventilator-induced lung edema in mice. Poly-lactic-co-glycolic acid NPs containing RR were evaluated in vitro for their ability to block TRPV4-mediated calcium signaling in alveolar macrophages and capillary endothelial cells. Lungs from adult C57BL6 mice treated with nebulized NPs were then used in ex vivo ventilation perfusion experiments to assess the ability of the NPs to prevent high-pressure mechanical ventilation–induced lung edema. Poly-lactic-co-glycolic acid NPs (300 nm) released RR for 150 hours in vitro, and blocked TRPV4-mediated calcium signaling in cells up to 7 days after phagocytosis. Inhaled NPs deposited in alveoli of spontaneously breathing mice were rapidly phagocytosed by alveolar macrophages, and blocked increased vascular permeability from high-pressure mechanical ventilation for 72 hours in ex vivo ventilation perfusion experiments. These data offer proof of principle that inhalation of NPs containing a TRPV4 inhibitor prevents ventilator damage for several days, and imply that this novel drug delivery strategy could be used to target alveolar macrophages in patients at risk of ventilator-induced lung injury before initiating mechanical ventilation. PMID:24405281

  15. Protective garment ventilation system

    NASA Technical Reports Server (NTRS)

    Lang, R. (inventor)

    1970-01-01

    A method and apparatus for ventilating a protective garment, space suit system, and/or pressure suits to maintain a comfortable and nontoxic atmosphere within is described. The direction of flow of a ventilating and purging gas in portions of the garment may be reversed in order to compensate for changes in environment and activity of the wearer. The entire flow of the ventilating gas can also be directed first to the helmet associated with the garment.

  16. Intratumoral patterns of genomic imbalance in glioblastomas.

    PubMed

    Nobusawa, Sumihito; Lachuer, Joel; Wierinckx, Anne; Kim, Young Ho; Huang, Jian; Legras, Catherine; Kleihues, Paul; Ohgaki, Hiroko

    2010-09-01

    Glioblastomas are morphologically and genetically heterogeneous, but little is known about the regional patterns of genomic imbalance within glioblastomas. We recently established a reliable whole genome amplification (WGA) method to randomly amplify DNA from paraffin-embedded histological sections with minimum amplification bias [Huang et al (J Mol Diagn 11: 109-116, 2009)]. In this study, chromosomal imbalance was assessed by array comparative genomic hybridization (CGH; Agilent 105K, Agilent Technologies, Santa Clara, CA, USA), using WGA-DNA from two to five separate tumor areas of 14 primary glioblastomas (total, 41 tumor areas). Chromosomal imbalances significantly differed among glioblastomas; the only alterations that were observed in > or =6 cases were loss of chromosome 10q, gain at 7p and loss of 10p. Genetic alterations common to all areas analyzed within a single tumor included gains at 1q32.1 (PIK3C2B, MDM4), 4q11-q12 (KIT, PDGFRA), 7p12.1-11.2 (EGFR), 12q13.3-12q14.1 (GLI1, CDK4) and 12q15 (MDM2), and loss at 9p21.1-24.3 (p16(INK4a)/p14(ARF)), 10p15.3-q26.3 (PTEN, etc.) and 13q12.11-q34 (SPRY2, RB1). These are likely to be causative in the pathogenesis of glioblastomas (driver mutations). In addition, there were numerous tumor area-specific genomic imbalances, which may be either nonfunctional (passenger mutations) or functional, but constitute secondary events reflecting progressive genomic instability, a hallmark of glioblastomas. PMID:20406234

  17. Review of Residential Ventilation Technologies

    SciTech Connect

    Armin Rudd

    2005-08-30

    This paper reviews current and potential ventilation technologies for residential buildings, including a variety of mechanical systems, natural ventilation, and passive ventilation. with particular emphasis on North American climates and construction.

  18. Multifamily Ventilation Retrofit Strategies

    SciTech Connect

    Ueno, K.; Lstiburek, J.; Bergey, D.

    2012-12-01

    In multifamily buildings, central ventilation systems often have poor performance, overventilating some portions of the building (causing excess energy use), while simultaneously underventilating other portions (causing diminished indoor air quality). BSC and Innova Services Corporation performed a series of field tests at a mid-rise test building undergoing a major energy audit and retrofit, which included ventilation system upgrades.

  19. Guide to Home Ventilation

    SciTech Connect

    2010-10-01

    A fact sheet from the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy: Ventilation refers to the exchange of indoor and outdoor air. Without proper ventilation, an otherwise insulated and airtight house will seal in harmful pollutants, such as carbon monoxide, and moisture that can damage a house.

  20. Home Ventilator Guide

    MedlinePLUS

    ... High FiO 2 , Ventilation not started/stopped, Circuit fault, Low/High PEEP, Pressure line disconnected H, O ... High FiO 2 , Ventilation not started/stopped, Circuit fault, Low/High PEEP, Pressure line disconnected H, O ...

  1. Lung-derived soluble mediators are pathogenic in ventilator-induced lung injury.

    PubMed

    Jaecklin, Thomas; Engelberts, Doreen; Otulakowski, Gail; O'Brodovich, Hugh; Post, Martin; Kavanagh, Brian P

    2011-04-01

    Ventilator-induced lung injury (VILI) due to high tidal volume (V(T)) is associated with increased levels of circulating factors that may contribute to, or be markers of, injury. This study investigated if exclusively lung-derived circulating factors produced during high V(T) ventilation can cause or worsen VILI. In isolated perfused mouse lungs, recirculation of perfusate worsened injury (compliance impairment, microvascular permeability, edema) induced by high V(T). Perfusate collected from lungs ventilated with high V(T) and used to perfuse lungs ventilated with low V(T) caused similar compliance impairment and permeability and caused a dose-dependent decrease in transepithelial electrical resistance (TER) across rat distal lung epithelial monolayers. Circulating soluble factors derived from the isolated lung thus contributed to VILI and had deleterious effects on the lung epithelial barrier. These data demonstrate transferability of an injury initially caused exclusively by mechanical ventilation and provides novel evidence for the biotrauma hypothesis in VILI. Mediators of the TER decrease were heat-sensitive, transferable via Folch extraction, and (following ultrafiltration, 3 kDa) comprised both smaller and larger molecules. Although several classes of candidate mediators, including protein cytokines (e.g., tumor necrosis factor-?, interleukin-6, macrophage inflammation protein-1?) and lipids (e.g., eicosanoids, ceramides, sphingolipids), have been implicated in VILI, only prostanoids accumulated in the perfusate in a pattern consistent with a pathogenic role, yet cyclooxygenase inhibition did not protect against injury. Although no single class of factor appears solely responsible for the decrease in barrier function, the current data implicate lipid-soluble protein-bound molecules as not just markers but pathogenic mediators in VILI. PMID:21239530

  2. Distributed Perfusion Educational Model: A Shift in Perfusion Economic Realities

    PubMed Central

    Austin, Jon W.; Evans, Edward L.; Hoerr, Harry R.

    2005-01-01

    Abstract: In recent years, a steady decline in the number of perfusion education programs in the United States has been noted. At the same time, there has been a parallel decline in the number of students graduated from perfusion educational programs in the United States. Also, as noted by several authors, there has been an increase in demand for perfusion graduates. The decline in programs and graduates has also been noted in anesthesia and surgical residency programs. The shift is caused by a combination of economic and clinical factors. First, decreased reimbursement has led to reallocation of hospital resources. Second, the original enthusiasm for beating heart coronary artery bypass surgery was grossly overestimated and has led to further reallocation of hospital resources and denigration of cardiopulmonary bypass. This paper describes two models of perfusion education programs: serial perfusion education model (SPEM) and the distributed perfusion education model (DPEM). Arguments are presented that the SPEM has some serious limitations and challenges for long-term economic survival. The authors feel the DPEM along with dependence on tuition funding can survive the current clinical and economic conditions and allow the profession to adapt to changes in scope of practice. PMID:16524152

  3. Adaptive lung ventilation.

    PubMed

    Linton, D M

    2001-09-01

    Adaptive lung ventilation (ALV) is a method of closed-loop mechanical ventilation analogous to modern closed-loop technology in aviation such as the autopilot and automatic landing system. The algorithm of the controller of ALV is designed to automatically provide pressure-controlled synchronized intermittent mandatory ventilation (P-SIMV) and weaning as individually required in any clinical situation. The synchronized pressure limited breaths constantly adapt to the patient requirements to encourage optimal alveolar ventilation with minimal adverse physiological disturbance and timely weaning. The ease of application, efficiency, and safety of the first ALV controllers have been demonstrated in lung models, in patients with normal lungs undergoing general anesthesia, in patients requiring unusual positioning, in transition to and from one-lung anesthesia, and in long-term ventilation of patients with various lung pathologies and in weaning patients who have restrictive or obstructive pulmonary disease. Prospective comparative studies of ALV versus other currently used manually selected modes of mechanical ventilation, such as the one reported in this article, should confirm the safety and identify the benefits of this form of advanced closed-loop mechanical ventilation technology. PMID:11517031

  4. Ventilating Air-Conditioner

    NASA Technical Reports Server (NTRS)

    Dinh, Khanh

    1994-01-01

    Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

  5. Adaptive Support Ventilation (ASV).

    PubMed

    Brunner, J X; Iotti, G A

    2002-05-01

    Adaptive Support Ventilation is a novel ventilation mode, a closed-loop control mode that may switch automatically from a PCV-like behaviour to an SIMV-like or PSV-like behaviour, according to the patient status. The operating principles are based on pressure-controlled SIMV with pressure levels and SIMV rate automatically adjusted according to measured lung mechanics at each breath. ASV provided a safe and effective ventilation in patients with normal lungs, restrective or obstructive diseases. In cardiac surgery tracheal extrubation was faster in ASV patients then in controls. In the early weaning phase of acute ventilatory insufficiency the need of resetting ventilator parameters was decreased, suggesting potential benefit for patient care. PMID:12029247

  6. Why We Ventilate

    SciTech Connect

    Logue, Jennifer M.; Sherman, Max H.; Price, Phil N.; Singer, Brett C.

    2011-09-01

    It is widely accepted that ventilation is critical for providing good indoor air quality (IAQ) in homes. However, the definition of"good" IAQ, and the most effective, energy efficient methods for delivering it are still matters of research and debate. This paper presents the results of work done at the Lawrence Berkeley National Lab to identify the air pollutants that drive the need for ventilation as part of a larger effort to develop a health-based ventilation standard. First, we present results of a hazard analysis that identified the pollutants that most commonly reach concentrations in homes that exceed health-based standards or guidelines for chronic or acute exposures. Second, we present results of an impact assessment that identified the air pollutants that cause the most harm to the U.S. population from chronic inhalation in residences. Lastly, we describe the implications of our findings for developing effective ventilation standards.

  7. A Resonant Synchronous Vibration Based Approach for Rotor Imbalance Detection

    NASA Technical Reports Server (NTRS)

    Luo, Huangeng; Rodriquez, Hector; Hallman, Darren; Lewicki, David G.

    2006-01-01

    This paper presents a methodology of detecting rotor imbalances, such as mass imbalance and crack-induced imbalance, using shaft synchronous vibrations. An iterative scheme is developed to identify parameters from measured synchronous vibration data. A detection system is integrated by using state-of-the-art commercial analysis equipment. A laboratory rotor test rig is used to verify the system integration and algorithm validation. A real engine test has been carried out and the results are reported.

  8. Conventional mechanical ventilation

    PubMed Central

    Tobias, Joseph D.

    2010-01-01

    The provision of mechanical ventilation for the support of infants and children with respiratory failure or insufficiency is one of the most common techniques that are performed in the Pediatric Intensive Care Unit (PICU). Despite its widespread application in the PICUs of the 21st century, before the 1930s, respiratory failure was uniformly fatal due to the lack of equipment and techniques for airway management and ventilatory support. The operating rooms of the 1950s and 1960s provided the arena for the development of the manual skills and the refinement of the equipment needed for airway management, which subsequently led to the more widespread use of endotracheal intubation thereby ushering in the era of positive pressure ventilation. Although there seems to be an ever increasing complexity in the techniques of mechanical ventilation, its successful use in the PICU should be guided by the basic principles of gas exchange and the physiology of respiratory function. With an understanding of these key concepts and the use of basic concepts of mechanical ventilation, this technique can be successfully applied in both the PICU and the operating room. This article reviews the basic physiology of gas exchange, principles of pulmonary physiology, and the concepts of mechanical ventilation to provide an overview of the knowledge required for the provision of conventional mechanical ventilation in various clinical arenas. PMID:20927268

  9. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  10. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  11. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  12. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  13. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  14. Autonomic Imbalance and Borderline States of Thyrotoxicosis

    PubMed Central

    Martin, Laurence

    1939-01-01

    Primary thyrotoxicosis may be regarded as having two main components—thyroid overactivity or dysfunction, and instability of the autonomic nervous system. Clinical observation suggests that the proportion of each component varies in individual cases. Results of treatment show that the larger the thyroid element the greater is the benefit of thyroidectomy or X-ray therapy, and the fewer the subsequent residual signs. When nervous instability predominates less relief is obtained by surgery or X-rays, and symptoms may be little changed or even made worse by the addition of hypothyroidism. Cases in which nervous instability predominates, with minimal thyroid dysfunction, have been termed “autonomic imbalance”, “neurocirculatory asthenia”, or “Basedow's disease with no thyrotoxicosis”. Thirteen such cases are described, all of which were females, with average age of 32 years. 9 had enlarged thyroids, 11 complained of palpitations, and 8 of excessive sweating. The basal metabolic rate, estimated in 8 cases, did not exceed +10%. There was some loss of weight in 6 cases, but in none was the appetite increased. The average diurnal pulse-rate did not exceed 95 and sleeping pulse was significantly lower. X-rays of heart, taken in 6 cases, were normal. Psychological troubles in 6 cases. Three cases treated by X-ray therapy and I surgically with no benefit. Remaining 10 cases treated medically with improvement. The group is ill-defined and requires further investigation of cause and treatment. The recognition of autonomic imbalance is important in order to avoid useless thyroidectomy or X-ray therapy, and encourage more extended use of psychotherapy. Investigation of its cause may yield information of value in the ætiological problem of thyrotoxicosis. PMID:19992127

  15. Imbalance of Water as an Example of Fundamental Imbalance of Nature.

    NASA Astrophysics Data System (ADS)

    Nechayev, A.

    2012-12-01

    Water is one of the main attributes of the world around us. Turning into ice or water vapor it controls a wide range of natural phenomena. It is one of the most moving substances of Earth and in it as in a mirror all imbalance of the Nature reflects. The laws that govern the water are above all the laws of classical physics, laws of motion and conservation. They determine an equilibrium state and out of it when the balance of forces, flows and energy is disturbed. Volcanic eruption, earthquake, tsunami, hurricane or tornado formation are the extreme form of imbalance of Nature. Unfortunately they are involved in it as a genetic feature. Mass and energy flows pervade the natural world. The structure of the space makes them come into conflict. Internal stress increase, there is an imbalance resulting in the fast, catastrophic events. Whether it is possible to understand the reasons of similar imbalance and to find its critical conditions? The water in their states shows the most striking examples of imbalance of Nature. If the equilibrium of forces and flows is disturbed the nature of movement can fundamentally change. The dependence of the total flux I flowing through the structure of the pressure drop ?p causing this flow can serve as an important informative characteristic for the imbalance phenomena connected with water. This «flow - forcing» characteristic I(?p) qualitatively changes its form with changes of so-called bifurcation parameter. From monotonous it can become S- or N-shaped. The approach to the analysis of Nature imbalance phenomenon can be illustrated by geyser eruption mechanism which is theoretically described in (Nechayev, 2012). One-dimensional motion of water flow in the geyser conduit obeys the Navier-Stokes equation. The influx of masses of water vapor due to water boiling in an underground chamber creates increasing overpressure. Bifurcation parameter is the volume of this chamber. There is a critical value of this volume (as compared with the volume of conduit) when the acceleration of the flow becomes positive and the eruption starts. The steady-state characteristic I (?p) can become S-shaped. The process of the volcanic eruption development is probably similar. In our opinion the main driving power of volcanic eruption is a contact of deep water-bearing layers to the magmatic chamber. Thermal energy of magma is transferred to the overpressure of superheated water vapor in some porous zone which is isolated from the surface. Bifurcation parameter is the volume of this vapor area. The magnitude of this volume determines the power of eruption, the velocities of lava and pyroclastic material. For the hurricanes too it is possible to find the analogous characteristic I (?p) (Nechayev, Solovyev, 2011). It can be the dependence of a full vertical air flow of horizontal pressure drop. Bifurcation parameter is the saturation mixing ratio of the moist air in the lower troposphere. Thus, despite all complexity of natural phenomena, it is possible to propose a generalized approach to the analysis of imbalance states of Nature taking into account the integral characteristics and corresponding bifurcation parameters.

  16. Increased Natural Ventilation Flow Rates through Ventilation Shafts

    E-print Network

    Ray, Stephen D.

    Buoyancy-driven natural ventilation in ventilation shafts is investigated with a small scale physical experiment within a duct and CFD simulations of an office building. For a fixed exhaust opening, smaller shafts lead to ...

  17. Catheter based magnetic resonance compatible perfusion probe

    E-print Network

    Toretta, Cara Lynne

    2007-01-01

    Neurosurgeons are using a thermal based technique to quantify brain perfusion. The thermal diffusion probe (TDP) technology measures perfusion in a relatively small volume of brain tissue. The neurosurgeon chooses the ...

  18. A WORKING PAPER ON PROBLEMS OF RACIAL IMBALANCE IN SCHOOLS.

    ERIC Educational Resources Information Center

    BUCHMILLER, A.A.; TEITEL, MARTIN

    THIS ANALYSIS OF NORTHERN DE FACTO SCHOOL SEGREGATION AND RACIAL IMBALANCE REVIEWS THE LEGAL ISSUES AND COURT DECISIONS GERMANE TO VARIOUS DESEGREGATION EFFORTS. IT IS NOTED THAT ALTHOUGH HOUSING PATTERNS MAY ACCOUNT FOR A LARGE PART OF THE RACIAL IMBALANCE IN SCHOOLS, GERRYMANDERING OF DISTRICT BOUNDARIES PLAYS A VERY SIGNIFICANT ROLE. SCHOOL…

  19. The Dilemma of Racial Imbalance in the Schools

    ERIC Educational Resources Information Center

    Kindsvatter, Richard; Wilen, William

    1974-01-01

    Outlines aims and program strategies for school districts to consider in attempting to cope with four problem areas associated with racial imbalance: imbalance in the black minority school population across a school district; segregation resulting from current school attendance boundaries; segregation or resegregation resulting from…

  20. Covariate Imbalance and Precision in Measuring Treatment Effects

    ERIC Educational Resources Information Center

    Liu, Xiaofeng Steven

    2011-01-01

    Covariate adjustment can increase the precision of estimates by removing unexplained variance from the error in randomized experiments, although chance covariate imbalance tends to counteract the improvement in precision. The author develops an easy measure to examine chance covariate imbalance in randomization by standardizing the average…

  1. Kinetics of reversible-sequestration of leukocytes by the isolated perfused rat lung

    SciTech Connect

    Goliaei, B.

    1980-08-01

    The kinetics and morphology of sequestration and margination of rat leukocytes were studied using an isolated perfused and ventilated rat lung preparation. Whole rat blood, bone marrow suspension, or leukocyte suspensions, were used to perfuse the isolated rat lung. The lung was also perfused with latex particle suspensions and the passage of particles through the lung capillaries was studied. When a leukocyte suspension was perfused through the lung in the single-pass mode, the rate of sequestration decreased as more cells were perfused. In contrast, latex particles of a size comparable to that of leukocytes were totally stopped by the lung. When the leukocyte suspension was recirculated through the lung, cells were rapidly removed from circulation until a steady state was reached, after which no net removal of cells by the lung occurred. These results indicate that leukocytes are reversibly sequestered from circulation. The sequestered cells marginated and attached to the luminal surface of the endothelium of post-capillary venules and veins. A mathematical model was developed based on the assumption that the attachment and detachment of leukocytes to blood vessel walls follows first-order kinetics. The model correctly predicts the following characteristics of the system: (a) the kinetics of the sequestration of leukocytes by the lung; (b) the existence of a steady state when a suspension of leukocytes is recirculated through the lung; and (c) the independence of the fraction of cells remaining in circulation from the starting concentration for all values of starting concentration. (ERB)

  2. Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems

    SciTech Connect

    Sherman, Max H.; Walker, Iain S.

    2011-04-01

    Existing ventilation standards, including American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) Standard 62.2, specify continuous operation of a defined mechanical ventilation system to provide minimum ventilation, with time-based intermittent operation as an option. This requirement ignores several factors and concerns including: other equipment such as household exhaust fans that might incidentally provide ventilation, negative impacts of ventilation when outdoor pollutant levels are high, the importance of minimizing energy use particularly during times of peak electricity demand, and how the energy used to condition air as part of ventilation system operation changes with outdoor conditions. Dynamic control of ventilation systems can provide ventilation equivalent to or better than what is required by standards while minimizing energy costs and can also add value by shifting load during peak times and reducing intake of outdoor air contaminants. This article describes the logic that enables dynamic control of whole-house ventilation systems to meet the intent of ventilation standards and demonstrates the dynamic ventilation system control concept through simulations and field tests of the Residential Integrated Ventilation-Energy Controller (RIVEC).

  3. Ventilation technologies scoping study

    SciTech Connect

    Walker, Iain S.; Sherman, Max H.

    2003-09-30

    This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the needs of California, determining residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and level of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  4. Non invasive ventilation.

    PubMed

    Sidhu, U S; Simonds, A K

    2000-04-01

    Non-invasive ventilation refers to the technique of providing ventilatory support to a patient without an endo/orotracheal airway. It is a promising and rapidly upcoming new technique and is being used as first line therapy in a wide variety of conditions causing respiratory failure. The major indications for its use include respiratory failure due to a variety of causes (chest wall abnormalities, neuromuscular disease, COPD), weaning and stabilization of cardio-respiratory status before and after surgery. Patients who are candidates for this modality usually have a hypercapnic respiratory failure but are able to protect the airway and cooperate with treatment. The biggest advantage of the technique is its simplicity and avoidance of complications of intubation like trauma, infection and delayed complications like tracheal stenosis. Patient comfort is significantly improved and important functions like speech, swallowing and cough are preserved. Several purpose built ventilators are available for use including pressure preset and volume present machines, each of which have their own advantages and disadvantages in clinical practice. A range of patient interfaces is available. The initiation of non-invasive ventilation is much easier as compared to invasive ventilation and can be done for most patients in an intermediary care unit thereby cutting down treatment costs and saving precious intensive care beds. Titration of ventilatory parameters can usually be done using simple tests like oxymetry and blood gases. Several technique related problems like skin pressure sores, nasal symptoms and abdominal distension can be managed with simple measures. Non invasive ventilation has got a special and evolving role in management of COPD, both in acute exacerbations and chronic respiratory failure. In short, the advantages of this form of ventilation are numerous and physicians must familiarize themselves with this new technique, facilities for which should be available in all hospitals admitting patients with respiratory failure. PMID:11273177

  5. Natural ventilation generates building form

    E-print Network

    Chen, Shaw-Bing

    1996-01-01

    Natural ventilation is an efficient design strategy for thermal comfort in hot and humid climates. The building forms can generate different pressures and temperatures to induce natural ventilation. This thesis develops a ...

  6. Innovative Energy Efficient Industrial Ventilation 

    E-print Network

    Litomisky, A.

    2005-01-01

    This paper was written to describe an innovative “on-demand” industrial ventilation system for woodworking, metalworking, food processing, pharmaceutical, chemical, and other industries. Having analyzed existing industrial ventilation in 130...

  7. Central Fan Integrated Ventilation Systems

    SciTech Connect

    2009-05-12

    This information sheet describes one example of a ventilation system design, a central fan integrated supply (CFIS) system, a mechanical ventilation and pollutant source control to ensure that there is reasonable indoor air quality inside the house.

  8. Ventilation flow: Submerged

    NASA Technical Reports Server (NTRS)

    Hutchinson, D.

    1985-01-01

    The ventilation system on a submarine is discussed. When the submarine is submerged. The ventilation system provides a conditioned atmosphere in the ship with complete isolation from the outside. A conditioned atmosphere includes not only filtration and temperature and humidity control, but also air purification (removal of potentially harmful quantities of impurities and comtaminants) and revitalization (addition of vital life support oxygen). Carbon dioxide removal, the oxygen system, air conditioning, carbon monoxide removal, hydrogen removal, and atmosphere monitoring systems are among the topics discussed.

  9. Noninvasive ventilation in withdrawal from mechanical ventilation.

    PubMed

    Ferrer, Miquel; Sellares, Jacobo; Torres, Antoni

    2014-08-01

    Patients with chronic airflow obstruction and difficult or prolonged weaning are at increased risk for prolonged invasive mechanical ventilation (IMV). Several randomized controlled trials mainly conducted in patients who had pre-existing lung disease have shown that the use of noninvasive ventilation (NIV) to advance extubation in patients with difficult and prolonged weaning can result in reduced periods of endotracheal intubation, complication rates, and improved survival. Patients in these studies were hemodynamically stable, with a normal level of consciousness, no fever, and a preserved cough reflex. The use of NIV in the management of mixed populations with respiratory failure after extubation, including small proportions of chronic respiratory patients did not show clinical benefits included. By contrast, NIV immediately after extubation is effective in avoiding respiratory failure after extubation and improving survival in patients at risk for this complication, particularly those with chronic respiratory disorders, cardiac comorbidity, and hypercapnic respiratory failure. Finally, both continuous positive airway pressure and NIV can improve clinical outcomes in patients with postoperative acute respiratory failure, particularly abdominal and thoracic surgery. PMID:25111647

  10. [Optimising speech during artificial ventilation].

    PubMed

    Gonzalez-Bermejo, J; Prigent, H

    2005-09-01

    Speech is an essential component of quality of life for patients treated with long term mechanical ventilation. Therefore trying to improve phonation should always sought by physicians treating these patients. We review the different tools and techniques available in order to restore speech for patients with home mechanical ventilation whether ventilation is done continuously or not. PMID:16294188

  11. RESIDENTIAL VENTILATION AND ENERGY CHARACTERISTICS*

    E-print Network

    RESIDENTIAL VENTILATION AND ENERGY CHARACTERISTICS* Max Sherman Nance Matson Energy Performance Berkeley, California The role of ventilation in the housing stock is to provide fresh air and to dilute to provide this ventilation service, either directly for moving the air or indirectly for conditioning

  12. How to Plan Ventilation Systems.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1963-01-01

    Ventilation systems for factory safety demand careful planning. The increased heat loads and new processes of industry have introduced complex ventilation problems in--(1) ventilation supply, (2) duct work design, (3) space requirements, (4) hood face velocities, (5) discharge stacks, and (6) building eddies. This article describes and diagrams…

  13. Immunological hazards from nutritional imbalance in athletes.

    PubMed

    Shephard, R J; Shek, P N

    1998-01-01

    This review examines the influences of nutritional imbalance on immune function of competitive athletes, who may adopt an unusual diet in an attempt to enhance performance. A major increase in body fat can have adverse effects on immune response. In contrast, a negative energy balance and reduction of body mass are likely to impair immune function in an already thin athlete. A moderate increase in polyunsaturated fat enhances immune function, but excessive consumption can be detrimental. Since endurance exercise leads to protein catabolism, an athlete may need 2.0 g/kg protein rather than the 0.7-1.0 g/kg recommended for a sedentary individual. Both sustained exercise and overtraining reduce plasma glutamine levels, which may contribute to suppressed immune function postexercise. A large intake of carbohydrate counters glutamine depletion but may also modify immune responses by altering the secretion of glucose-regulating hormones. Vitamins are important to immune function because of their antioxidant role. However, the clinical benefits of vitamin C supplementation are not enhanced by the use of more complex vitamin mixtures, and excessive vitamin E can have negative effects. Iron, selenium, zinc, calcium, and magnesium ion all influence immune function. Supplements may be required after heavy sweating, but an excessive intake of iron facilitates bacterial growth. In making dietary recommendations to athletes, it is important to recognize that immune response can be jeopardized not only by deficiencies but also by excessive intake of certain nutrients. The goal should be a well-balanced diet. PMID:9644093

  14. Spatial-frequency dependent binocular imbalance in amblyopia

    PubMed Central

    Kwon, MiYoung; Wiecek, Emily; Dakin, Steven C.; Bex, Peter J.

    2015-01-01

    While amblyopia involves both binocular imbalance and deficits in processing high spatial frequency information, little is known about the spatial-frequency dependence of binocular imbalance. Here we examined binocular imbalance as a function of spatial frequency in amblyopia using a novel computer-based method. Binocular imbalance at four spatial frequencies was measured with a novel dichoptic letter chart in individuals with amblyopia, or normal vision. Our dichoptic letter chart was composed of band-pass filtered letters arranged in a layout similar to the ETDRS acuity chart. A different chart was presented to each eye of the observer via stereo-shutter glasses. The relative contrast of the corresponding letter in each eye was adjusted by a computer staircase to determine a binocular Balance Point at which the observer reports the letter presented to either eye with equal probability. Amblyopes showed pronounced binocular imbalance across all spatial frequencies, with greater imbalance at high compared to low spatial frequencies (an average increase of 19%, p?imbalance may be useful for diagnosing amblyopia and as an outcome measure for recovery of binocular vision following therapy. PMID:26603125

  15. Spatial-frequency dependent binocular imbalance in amblyopia.

    PubMed

    Kwon, MiYoung; Wiecek, Emily; Dakin, Steven C; Bex, Peter J

    2015-01-01

    While amblyopia involves both binocular imbalance and deficits in processing high spatial frequency information, little is known about the spatial-frequency dependence of binocular imbalance. Here we examined binocular imbalance as a function of spatial frequency in amblyopia using a novel computer-based method. Binocular imbalance at four spatial frequencies was measured with a novel dichoptic letter chart in individuals with amblyopia, or normal vision. Our dichoptic letter chart was composed of band-pass filtered letters arranged in a layout similar to the ETDRS acuity chart. A different chart was presented to each eye of the observer via stereo-shutter glasses. The relative contrast of the corresponding letter in each eye was adjusted by a computer staircase to determine a binocular Balance Point at which the observer reports the letter presented to either eye with equal probability. Amblyopes showed pronounced binocular imbalance across all spatial frequencies, with greater imbalance at high compared to low spatial frequencies (an average increase of 19%, p?imbalance may be useful for diagnosing amblyopia and as an outcome measure for recovery of binocular vision following therapy. PMID:26603125

  16. RESIDENTIAL VENTILATION STUDY

    EPA Science Inventory

    This project evaluated the effectiveness, first costs and operational costs of various types of residential ventilation systems in three different climates in the U.S. The Agency, through its Energy Star Program, recommends that builders construct homes that are energy efficient ...

  17. Measure Guideline: Ventilation Cooling

    SciTech Connect

    Springer, D.; Dakin, B.; German, A.

    2012-04-01

    The purpose of this measure guideline on ventilation cooling is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

  18. Space station ventilation study

    NASA Technical Reports Server (NTRS)

    Colombo, G. V.; Allen, G. E.

    1972-01-01

    A ventilation system design and selection method which is applicable to any manned vehicle were developed. The method was used to generate design options for the NASA 33-foot diameter space station, all of which meet the ventilation system design requirements. System characteristics such as weight, volume, and power were normalized to dollar costs for each option. Total system costs for the various options ranged from a worst case $8 million to a group of four which were all approximately $2 million. A system design was then chosen from the $2 million group and is presented in detail. A ventilation system layout was designed for the MSFC space station mockup which provided comfortable, efficient ventilation of the mockup. A conditioned air distribution system design for the 14-foot diameter modular space station, using the same techniques, is also presented. The tradeoff study resulted in the selection of a system which costs $1.9 million, as compared to the alternate configuration which would have cost $2.6 million.

  19. Influence of perfusate on liver viability during hypothermic machine perfusion

    PubMed Central

    Jia, Jun-Jun; Zhang, Jing; Li, Jian-Hui; Chen, Xu-Dong; Jiang, Li; Zhou, Yan-Fei; He, Ning; Xie, Hai-Yang; Zhou, Lin; Zheng, Shu-Sen

    2015-01-01

    AIM: To optimize the perfusates used for hypothermic machine perfusion (HMP). METHODS: Sprague-Dawley rats were assigned randomly to three groups (n = 12 per group) that received either saline, University of Wisconsin cold-storage solution (UW) or histidine-tryptophan-ketoglutarate solution (HTK) as the perfusate. Each group was divided into two subgroups: static cold storage (SCS) and HMP (n = 6 per subgroup). The liver graft was retrieved according to the method described by Kamada. For the SCS group, the graft was directly placed into cold perfusate (0-4?°C) for 6 h after liver isolation while the portal vein of the graft was connected to the perfusion machine for the HMP group. Then the perfusates were collected at different time points for analysis of aspartate aminotransferase (AST), alanine transaminase (ALT) and lactate dehydrogenase (LDH) levels. Liver tissues were obtained for evaluation of histology, dry/wet weight (D/W) ratio, and malondialdehyde (MDA) and adenosine-triphosphate (ATP) levels. The portal vein pressure and velocity were monitored in real time in all HMP subgroups. RESULTS: Comparison of HMP and SCS: Regardless of the perfusate, HMP improved the architecture of donor graft in reducing the congestion around sinusoids and central vein and maintaining sinusoid lining in morphology; HMP improved liver function in terms of ALT, AST and LDH, especially during the 3-6 h period (SCS vs HMP using saline: ALT3, 225.00 ± 105.62 vs 49.50 ± 18.50, P = 0.047; LDH3, 1362.17 ± 563.30 vs 325.75 ± 147.43, P = 0.041; UW: LDH6, 2880.14 ± 948.46 vs 2135.00 ± 174.27, P = 0.049; HTK, AST6, 307.50 ± 52.95 vs 185.20 ± 20.46, P = 0.041); HMP decreased MDA level (saline, 2.79 ± 0.30 vs 1.09 ± 0.09, P = 0.008; UW, 3.01 ± 0.77 vs 1.23 ± 0.68, P = 0.005; HTK, 3.30 ± 0.52 vs 1.56 ± 0.22, P = 0.006). Comparison among HMP subgroups: HTK showed less portal vein resistance than UW and saline (vs saline, 3.41 ± 0.49 vs 5.00 ± 0.38, P < 0.001; vs UW, 3.41 ± 0.49 vs 4.52 ± 0.63, P = 0.007); UW reduced edema most efficiently (vs saline, 0.68 ± 0.02 vs 0.79 ± 0.05, P = 0.013), while HTK maintained ATP levels best (vs saline, 622.60 ± 29.11 vs 327.43 ± 44.66, P < 0.001; vs UW, 622.60 ± 29.11 vs 301.80 ± 37.68, P < 0.001). CONCLUSION: HMP is superior to SCS in maintaining both architecture and function of liver grafts. Further, HTK was found to be the optimal perfusate for HMP. PMID:26269674

  20. ASHRAE and residential ventilation

    SciTech Connect

    Sherman, Max H.

    2003-10-01

    In the last quarter of a century, the western world has become increasingly aware of environmental threats to health and safety. During this period, people psychologically retreated away from outdoors hazards such as pesticides, smog, lead, oil spills, and dioxin to the seeming security of their homes. However, the indoor environment may not be healthier than the outdoor environment, as has become more apparent over the past few years with issues such as mold, formaldehyde, and sick-building syndrome. While the built human environment has changed substantially over the past 10,000 years, human biology has not; poor indoor air quality creates health risks and can be uncomfortable. The human race has found, over time, that it is essential to manage the indoor environments of their homes. ASHRAE has long been in the business of ventilation, but most of the focus of that effort has been in the area of commercial and institutional buildings. Residential ventilation was traditionally not a major concern because it was felt that, between operable windows and envelope leakage, people were getting enough outside air in their homes. In the quarter of a century since the first oil shock, houses have gotten much more energy efficient. At the same time, the kinds of materials and functions in houses changed in character in response to people's needs. People became more environmentally conscious and aware not only about the resources they were consuming but about the environment in which they lived. All of these factors contributed to an increasing level of public concern about residential indoor air quality and ventilation. Where once there was an easy feeling about the residential indoor environment, there is now a desire to define levels of acceptability and performance. Many institutions--both public and private--have interests in Indoor Air Quality (IAQ), but ASHRAE, as the professional society that has had ventilation as part of its mission for over 100 years, is the logical place to provide leadership. This leadership has been demonstrated most recently by the publication of the first nationally recognized standard on ventilation in homes, ASHRAE Standard 62.2-2003, which builds on work that has been part of ASHRAE for many years and will presumably continue. Homeowners and occupants, which includes virtually all of us, will benefit from the application of Standard 62.2 and use of the top ten list. This activity is exactly the kind of benefit to society that the founders of ASHRAE envisioned and is consistent with ASHRAE's mission and vision. ASHRAE members should be proud of their Society for taking leadership in residential ventilation.

  1. Impact of Energy Imbalance Tariff on Wind Energy

    SciTech Connect

    Wan, Y.; Milligan, M.; Kirby, B.

    2007-07-01

    This paper summarizes the results of a study that uses actual wind power data and actual energy prices to analyze the impact of an energy imbalance tariff imposed by the Federal Energy Regulatory Commission on wind power.

  2. Abnormalities of cerebral perfusion in multiple sclerosis

    PubMed Central

    Rashid, W; Parkes, L; Ingle, G; Chard, D; Toosy, A; Altmann, D; Symms, M; Tofts, P; Thompson, A; Miller, D

    2004-01-01

    Background: Measuring perfusion provides a potential indication of metabolic activity in brain tissue. Studies in multiple sclerosis (MS) have identified areas of decreased perfusion in grey matter (GM) and white matter (WM), but the pattern in clinical subgroups is unclear. Objectives: This study investigated perfusion changes in differing MS clinical subgroups on or off ß-interferon therapy using a non-invasive MRI technique (continuous arterial spin labelling) to investigate whether different clinical MS subtypes displayed perfusion changes and whether this could give a further insight into the pathological mechanisms involved. Methods: Sixty patients (21 relapsing remitting, 14 secondary progressive, 12 primary progressive, 13 benign) and 34 healthy controls were compared. Statistical parametric mapping (SPM '99) was used to investigate regional variations in perfusion in both GM and WM. Global WM perfusion was derived by segmenting WM from images using T1 relaxation times. Results: Regions of lower perfusion in predominantly GM were observed in the primary and secondary progressive cohorts, particularly in the thalamus. Increased WM perfusion was seen in relapsing remitting and secondary progressive cohorts. Conclusions: Low GM perfusion could reflect decreased metabolism secondary to neuronal and axonal loss or dysfunction with a predilection for progressive forms of MS. Increased WM perfusion may indicate increased metabolic activity possibly due to increased cellularity and inflammation. Improved methodology and longitudinal studies may enable further investigation of regional and temporal changes, and their relationship with physical and cognitive impairment. PMID:15314117

  3. Harnessing natural ventilation benefits.

    PubMed

    O'Leary, John

    2013-04-01

    Making sure that a healthcare establishment has a good supply of clean fresh air is an important factor in keeping patients, staff, and visitors, free from the negative effects of CO2 and other contaminants. John O'Leary of Trend Controls, a major international supplier of building energy management solutions (BEMS), examines the growing use of natural ventilation, and the health, energy-saving, and financial benefits, that it offers. PMID:23678661

  4. Improved Performance With Ventilation

    NASA Astrophysics Data System (ADS)

    Kawakami, Ellison; Lee, Seung Jae; Karn, Ashish; Hong, Jiarong; Arndt, Roger

    2013-11-01

    Drag reduction and/or speed augmentation of marine vehicles by means of supercavitation is a topic of great interest. During the initial launch of a supercavitating vehicle, ventilation is required to supply an artificial cavity until conditions at which a natural supercavity can be sustained are reached. Various aspects of the flow physics of a supercavitating vehicle have been under investigation for several years at Saint Anthony Falls Laboratory. Both steady flow and simulated flow below a wave train have been studied. Using a high speed camera and the proper software, it is possible to synchronize cavity dimensions with pressure measurements taken inside the cavity to permit an in-depth study of unsteadiness. It was found that flow unsteadiness caused a decrease in the overall length of the supercavity while having only a minimal effect on the maximum diameter. Results regarding supercavity shape, ventilation demand, cavitation parameters and closure methods are reviewed in light of new studies that focused on various closure mechanisms. Drag reduction and/or speed augmentation of marine vehicles by means of supercavitation is a topic of great interest. During the initial launch of a supercavitating vehicle, ventilation is required to supply an artificial cavity until conditions at which a natural supercavity can be sustained are reached. Various aspects of the flow physics of a supercavitating vehicle have been under investigation for several years at Saint Anthony Falls Laboratory. Both steady flow and simulated flow below a wave train have been studied. Using a high speed camera and the proper software, it is possible to synchronize cavity dimensions with pressure measurements taken inside the cavity to permit an in-depth study of unsteadiness. It was found that flow unsteadiness caused a decrease in the overall length of the supercavity while having only a minimal effect on the maximum diameter. Results regarding supercavity shape, ventilation demand, cavitation parameters and closure methods are reviewed in light of new studies that focused on various closure mechanisms. Sponsored by ONR.

  5. Ventilation Air Preconditioning Systems 

    E-print Network

    Khattar, M.; Brandemuehl, M. J.

    1996-01-01

    , maintaining excellent control of temperature and humidity within each zone. Filter racks are 4" deep to accommodate a wide range of highefficiency filters. Tempering Outside Air in Winter In winter, the recirculation air can be heated rather than cooled...-cooled refrigeration racks. Simulation of the WalMart superstore application of these units showed a potential cost savings of 22.6% over conventional WAC&R systems. Zero-ODP Refrigerant The ventilation chiller uses R-407C, an environmentally acceptable...

  6. Intestinal perfusion monitoring using photoplethysmography

    NASA Astrophysics Data System (ADS)

    Akl, Tony J.; Wilson, Mark A.; Ericson, M. Nance; Coté, Gerard L.

    2013-08-01

    In abdominal trauma patients, monitoring intestinal perfusion and oxygen consumption is essential during the resuscitation period. Photoplethysmography is an optical technique potentially capable of monitoring these changes in real time to provide the medical staff with a timely and quantitative measure of the adequacy of resuscitation. The challenges for using optical techniques in monitoring hemodynamics in intestinal tissue are discussed, and the solutions to these challenges are presented using a combination of Monte Carlo modeling and theoretical analysis of light propagation in tissue. In particular, it is shown that by using visible wavelengths (i.e., 470 and 525 nm), the perfusion signal is enhanced and the background contribution is decreased compared with using traditional near-infrared wavelengths leading to an order of magnitude enhancement in the signal-to-background ratio. It was further shown that, using the visible wavelengths, similar sensitivity to oxygenation changes could be obtained (over 50% compared with that of near-infrared wavelengths). This is mainly due to the increased contrast between tissue and blood in that spectral region and the confinement of the photons to the thickness of the small intestine. Moreover, the modeling results show that the source to detector separation should be limited to roughly 6 mm while using traditional near-infrared light, with a few centimeters source to detector separation leads to poor signal-to-background ratio. Finally, a visible wavelength system is tested in an in vivo porcine study, and the possibility of monitoring intestinal perfusion changes is showed.

  7. Intestinal perfusion monitoring using photoplethysmography

    PubMed Central

    Akl, Tony J.; Wilson, Mark A.; Ericson, M. Nance; Coté, Gerard L.

    2013-01-01

    Abstract. In abdominal trauma patients, monitoring intestinal perfusion and oxygen consumption is essential during the resuscitation period. Photoplethysmography is an optical technique potentially capable of monitoring these changes in real time to provide the medical staff with a timely and quantitative measure of the adequacy of resuscitation. The challenges for using optical techniques in monitoring hemodynamics in intestinal tissue are discussed, and the solutions to these challenges are presented using a combination of Monte Carlo modeling and theoretical analysis of light propagation in tissue. In particular, it is shown that by using visible wavelengths (i.e., 470 and 525 nm), the perfusion signal is enhanced and the background contribution is decreased compared with using traditional near-infrared wavelengths leading to an order of magnitude enhancement in the signal-to-background ratio. It was further shown that, using the visible wavelengths, similar sensitivity to oxygenation changes could be obtained (over 50% compared with that of near-infrared wavelengths). This is mainly due to the increased contrast between tissue and blood in that spectral region and the confinement of the photons to the thickness of the small intestine. Moreover, the modeling results show that the source to detector separation should be limited to roughly 6 mm while using traditional near-infrared light, with a few centimeters source to detector separation leads to poor signal-to-background ratio. Finally, a visible wavelength system is tested in an in vivo porcine study, and the possibility of monitoring intestinal perfusion changes is showed. PMID:23942635

  8. Pretest Predictions for Ventilation Tests

    SciTech Connect

    Y. Sun; H. Yang; H.N. Kalia

    2007-01-17

    The objective of this calculation is to predict the temperatures of the ventilating air, waste package surface, concrete pipe walls, and insulation that will be developed during the ventilation tests involving various test conditions. The results will be used as input to the following three areas: (1) Decisions regarding testing set-up and performance. (2) Assessing how best to scale the test phenomena measured. (3) Validating numerical approach for modeling continuous ventilation. The scope of the calculation is to identify the physical mechanisms and parameters related to thermal response in the ventilation tests, and develop and describe numerical methods that can be used to calculate the effects of continuous ventilation. Sensitivity studies to assess the impact of variation of linear power densities (linear heat loads) and ventilation air flow rates are included. The calculation is limited to thermal effect only.

  9. Comparison of CT-derived Ventilation Maps with Deposition Patterns of Inhaled Microspheres in Rats

    SciTech Connect

    Jacob, Rick E.; Lamm, W. J.; Einstein, Daniel R.; Krueger, Melissa; Glenny, Robb W.; Corley, Richard A.

    2015-04-01

    Purpose: Computer models for inhalation toxicology and drug-aerosol delivery studies rely on ventilation pattern inputs for predictions of particle deposition and vapor uptake. However, changes in lung mechanics due to disease can impact airflow dynamics and model results. It has been demonstrated that non-invasive, in vivo, 4DCT imaging (3D imaging at multiple time points in the breathing cycle) can be used to map heterogeneities in ventilation patterns under healthy and disease conditions. The purpose of this study was to validate ventilation patterns measured from CT imaging by exposing the same rats to an aerosol of fluorescent microspheres (FMS) and examining particle deposition patterns using cryomicrotome imaging. Materials and Methods: Six male Sprague-Dawley rats were intratracheally instilled with elastase to a single lobe to induce a heterogeneous disease. After four weeks, rats were imaged over the breathing cycle by CT then immediately exposed to an aerosol of ~1µm FMS for ~5 minutes. After the exposure, the lungs were excised and prepared for cryomicrotome imaging, where a 3D image of FMS deposition was acquired using serial sectioning. Cryomicrotome images were spatially registered to match the live CT images to facilitate direct quantitative comparisons of FMS signal intensity with the CT-based ventilation maps. Results: Comparisons of fractional ventilation in contiguous, non-overlapping, 3D regions between CT-based ventilation maps and FMS images showed strong correlations in fractional ventilation (r=0.888, p<0.0001). Conclusion: We conclude that ventilation maps derived from CT imaging are predictive of the 1µm aerosol deposition used in ventilation-perfusion heterogeneity inhalation studies.

  10. Vasomotor tone does not affect perfusion heterogeneity and gas exchange in normal primate lungs during normoxia

    NASA Technical Reports Server (NTRS)

    Glenny, R. W.; Robertson, H. T.; Hlastala, M. P.

    2000-01-01

    To determine whether vasoregulation is an important cause of pulmonary perfusion heterogeneity, we measured regional blood flow and gas exchange before and after giving prostacyclin (PGI(2)) to baboons. Four animals were anesthetized with ketamine and mechanically ventilated. Fluorescent microspheres were used to mark regional perfusion before and after PGI(2) infusion. The lungs were subsequently excised, dried inflated, and diced into approximately 2-cm(3) pieces (n = 1,208-1,629 per animal) with the spatial coordinates recorded for each piece. Blood flow to each piece was determined for each condition from the fluorescent signals. Blood flow heterogeneity did not change with PGI(2) infusion. Two other measures of spatial blood flow distribution, the fractal dimension and the spatial correlation, did not change with PGI(2) infusion. Alveolar-arterial O(2) differences did not change with PGI(2) infusion. We conclude that, in normal primate lungs during normoxia, vasomotor tone is not a significant cause of perfusion heterogeneity. Despite the heterogeneous distribution of blood flow, active regulation of regional perfusion is not required for efficient gas exchange.

  11. Mechanical Ventilation and Bronchopulmonary Dysplasia.

    PubMed

    Keszler, Martin; Sant'Anna, Guilherme

    2015-12-01

    Mechanical ventilation is an important potentially modifiable risk factor for the development of bronchopulmonary dysplasia. Effective use of noninvasive respiratory support reduces the risk of lung injury. Lung volume recruitment and avoidance of excessive tidal volume are key elements of lung-protective ventilation strategies. Avoidance of oxidative stress, less invasive methods of surfactant administration, and high-frequency ventilation are also important factors in lung injury prevention. PMID:26593078

  12. Myocardial perfusion imaging using contrast echocardiography.

    PubMed

    Pathan, Faraz; Marwick, Thomas H

    2015-01-01

    Microbubbles are an excellent intravascular tracer, and both the rate of myocardial opacification (analogous to coronary microvascular perfusion) and contrast intensity (analogous to myocardial blood volume) provide unique insights into myocardial perfusion. A strong evidence base has been accumulated to show comparability with nuclear perfusion imaging and incremental diagnostic and prognostic value relative to wall motion analysis. This technique also provides the possibility to measure myocardial perfusion at the bedside. Despite all of these advantages, the technique is complicated, technically challenging, and has failed to scale legislative and financial hurdles. The development of targeted imaging and therapeutic interventions will hopefully rekindle interest in this interesting modality. PMID:25817740

  13. Towards robust deconvolution of low-dose perfusion CT: Sparse perfusion deconvolution using online dictionary learning

    E-print Network

    Chen, Tsuhan

    Towards robust deconvolution of low-dose perfusion CT: Sparse perfusion deconvolution using online. In this paper, we propose a robust sparse perfusion deconvolution method (SPD) to estimate cerebral blood flow online dictionary learning and then perform deconvolution-based hemodynamic parameters estimation

  14. Loss-imbalance equalization of AWG-based OADM

    NASA Astrophysics Data System (ADS)

    Deng, Henghua; Wu, Deming; Xu, Anshi

    2000-10-01

    Integrated-Optic Arrayed Waveguide Grating (AWG) N X N multiplexers are a new focus in All Optical Networks (AON) for their unique N input and N output geometry and have been used in a variety of applications. All AWGs fabricated so far have shown loss-imbalance among FDM channels due to non-uniform diffraction efficiency. It is fatal in AON because it will accumulate after each AWG. Uniform diffraction efficiency obtained in ideal design limit is one ideal solution, but it is nearly impossible to achieve the ideal limit with present fabrication technology. This paper applies a new method -- shifted connection -- on equalizing loss-imbalance of AWG- based OADM. The basic idea is simple and the result is of great significance. We theoretically analyze the effect of 8 various shifted configurations and predict each effectiveness. We find the relationship between the loss-imbalance and shift (delta) is a quadratic equation. We extend the method to cascaded AWGs. Also we deduce the limit of the equalization, which is independent of m and AWG's loss-imbalance parameter (alpha) , (beta) . Experiment results accord with theory very well and show that we successfully reduce a worst case loss- imbalance (9.5 dB) to a best case loss-imbalance (3 dB) in a single AWG-based OADM. We find that equalization configuration with foldback path is superior to loopback path configurations, when no more than N/2 wavelengths are used. The method is very simple and effective in equalizing AWG's loss-imbalance and the idea can be applied to other equalizations in AON.

  15. [Possibilities and limitations of ventilation monitoring during anesthesia of the newborn and infants].

    PubMed

    Fösel, T; Altemeyer, K H; Heinrich, H; Lotz, P

    1984-01-01

    The following methods for monitoring the ventilation in general anaesthesia can theoretically be applied for neonates and small infants: The use of a precordial stethoscope, measurements and observation of the ventilation pressure, analysis of the inspiratory oxygen concentration, measurement of the expiratory volume, analysis of end-tidal CO2, transcutaneous O2 and CO2 measurement and blood gas analysis. These methods are evaluated and their limitations discussed. Special attention is paid to the application of these methods used in the different paediatric anaesthetic systems. A three graded plan which classifies the risks for the patients and/or the operations is presented in order to rationalize the use of these methods, some of which require expensive equipment. The basic ventilation monitoring includes, even for short operations in healthy patients (Grade I), the precordial stethoscope, the measurement of the inspiratory oxygen concentration, the measurement of the ventilation pressure and, for school age children also measurement of the expiratory volume. For operations lasting longer than one hour (Grade II) end-tidal CO2 analysis should be used when the ventilation-perfusion ratio is undisturbed. Transcutaneous O2 is desirable, but at the present time not accurate for conditions of general anaesthesia. For all high risk patients and/or operations (Grade III), particularly in the neonates, arterial blood gases are indispensable as well as the other methods for monitoring ventilation. PMID:6424495

  16. Potential Role of Lung Ventilation Scintigraphy in the Assessment of COPD

    PubMed Central

    Cukic, Vesna; Begic, Amela

    2014-01-01

    Objective: To highlight the importance of the lung ventilation scintigraphy (LVS) to study the regional distribution of lung ventilation and to describe most frequent abnormal patterns of lung ventilation distribution obtained by this technique in COPD and to compare the information obtained by LVS with the that obtained by traditional lung function tests. Material and methods: The research was done in 20 patients with previously diagnosed COPD who were treated in Intensive care unit of Clinic for pulmonary diseases and TB “Podhrastovi” Clinical Center, University of Sarajevo in exacerbation of COPD during first three months of 2014. Each patient was undergone to testing of pulmonary function by body plethysmography and ventilation/perfusion lung scintigraphy with radio pharmaceutics Technegas, 111 MBq Tc -99m-MAA. We compared the results obtained by these two methods. Results: All patients with COPD have a damaged lung function tests examined by body plethysmography implying airflow obstruction, but LVS indicates not only airflow obstruction and reduced ventilation, but also indicates the disorders in distribution in lung ventilation. Conclusion: LVS may add further information to the functional evaluation of COPD to that provided by traditional lung function tests and may contribute to characterizing the different phenotypes of COPD. PMID:25132709

  17. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Ventilation systems. 252.9 Section 252...SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever the ventilation system is not fully...

  18. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Crawlspace ventilation. 3285.505 Section 3285.505...Features § 3285.505 Crawlspace ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area...

  19. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation. 194.10-25 Section 194.10-25...MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. ...be provided with natural or mechanical ventilation. Design calculations shall be...

  20. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation. 194.20-5 Section 194...or Storerooms § 194.20-5 Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The...

  1. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Ventilation plan. 57.8520 Section 57.8520...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8520 Ventilation plan. A plan of the mine...

  2. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Ventilation plan. 57.8520 Section 57.8520...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8520 Ventilation plan. A plan of the mine...

  3. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation. 194.10-25 Section 194.10-25...MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. ...be provided with natural or mechanical ventilation. Design calculations shall be...

  4. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation. 194.20-5 Section 194...or Storerooms § 194.20-5 Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The...

  5. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Ventilation plan. 57.8520 Section 57.8520...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8520 Ventilation plan. A plan of the mine...

  6. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Ventilation systems. 252.9 Section 252...SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever the ventilation system is not fully...

  7. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Ventilation systems. 252.9 Section 252...SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever the ventilation system is not fully...

  8. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation. 194.10-25 Section 194.10-25...MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. ...be provided with natural or mechanical ventilation. Design calculations shall be...

  9. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Ventilation plan. 57.8520 Section 57.8520...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8520 Ventilation plan. A plan of the mine...

  10. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Crawlspace ventilation. 3285.505 Section 3285.505...Features § 3285.505 Crawlspace ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area...

  11. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation. 194.20-5 Section 194...or Storerooms § 194.20-5 Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The...

  12. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Crawlspace ventilation. 3285.505 Section 3285.505...Features § 3285.505 Crawlspace ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area...

  13. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Ventilation systems. 252.9 Section 252...SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever the ventilation system is not fully...

  14. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Crawlspace ventilation. 3285.505 Section 3285.505...Features § 3285.505 Crawlspace ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area...

  15. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation. 194.10-25 Section 194.10-25...MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. ...be provided with natural or mechanical ventilation. Design calculations shall be...

  16. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Ventilation plan. 57.8520 Section 57.8520...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8520 Ventilation plan. A plan of the mine...

  17. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation. 194.20-5 Section 194...or Storerooms § 194.20-5 Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The...

  18. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation. 194.20-5 Section 194...or Storerooms § 194.20-5 Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The...

  19. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation. 194.10-25 Section 194.10-25...MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. ...be provided with natural or mechanical ventilation. Design calculations shall be...

  20. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Ventilation systems. 252.9 Section 252...SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever the ventilation system is not fully...

  1. The impact of sample imbalance on identifying differentially expressed genes

    PubMed Central

    Yang, Kun; Li, Jianzhong; Gao, Hong

    2006-01-01

    Background Recently several statistical methods have been proposed to identify genes with differential expression between two conditions. However, very few studies consider the problem of sample imbalance and there is no study to investigate the impact of sample imbalance on identifying differential expression genes. In addition, it is not clear which method is more suitable for the unbalanced data. Results Based on random sampling, two evaluation models are proposed to investigate the impact of sample imbalance on identifying differential expression genes. Using the proposed evaluation models, the performances of six famous methods are compared on the unbalanced data. The experimental results indicate that the sample imbalance has a great influence on selecting differential expression genes. Furthermore, different methods have very different performances on the unbalanced data. Among the six methods, the welch t-test appears to perform best when the size of samples in the large variance group is larger than that in the small one, while the Regularized t-test and SAM outperform others on the unbalanced data in other cases. Conclusion Two proposed evaluation models are effective and sample imbalance should be taken into account in microarray experiment design and gene expression data analysis. The results and two proposed evaluation models can provide some help in selecting suitable method to process the unbalanced data. PMID:17217526

  2. Laboratory and Industrial Ventilation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This handbook supplements the Facilities Engineering Handbook (NHB 7320.1) and provides additional policies and criteria for uniform application to ventilation systems. It expands basic requirements, provides additional design and construction guidance, and places emphasis on those design considerations which will provide for greater effectiveness in the use of these systems. The provisions of this handbook are applicable to all NASA field installations and the Jet Propulsion Laboratory. Since supply of this handbook is limited, abstracts of the portion or portions applicable to a given requirement will be made for the individual specific needs encountered rather than supplying copies of the handbook as has been past practice.

  3. Lung-lung interaction in isolated perfused unilateral hyperventilated rat lungs.

    PubMed

    Bilali, Aishan; Kurata, Shunichi; Ikeda, Satoshi; Georgieva, Gabriela S; Zhu, Chenting; Tomita, Makoto; Katoh, Iyoko; Mitaka, Chieko; Eishi, Yoshinobu; Imai, Takasuke

    2010-05-01

    The technique of conducting high tidal volume (TV) ventilation-induced lung inflammation including remote organs is still open to discussion, and our aim is to investigate this issue in isolated ventilated rat lungs perfused with salt solution. Selective right lung (RL) hyperventilation (TV of 15 mL/kg with air containing 5% CO(2) on zero or 2.5 cm H(2)0 end expiratory pressure [ZEEP or PEEP] in addition to left lung (LL) on 2.5 cm H(2)0 continuous positive airway pressure (CPAP) for 60 min, was realized after 30 min both lungs ventilation by occluding the left main bronchus, and it was allocated to the following 5 groups: groups 1 and 2 underwent hyperventilation under ZEEP, groups 3 and 4 underwent hyper ventilation under PEEP with recirculation or nonrecirculation (R-ZEEP or NR-ZEEP and R-PEEP or NR-PEEP), and group 5 served as the control group. Recirculation means the same perfusate recirculates the system throughout the procedure. The wet/dry ratio and protein content of bronchoalveolar lavage fluid (Prot-BALF), cytokine messenger RNAs (mRNAs), localization of tumor necrosis factor-alpha (TNF-alpha) by immunofluorescence double staining, and TNF-alpha concentration in the perfusate and BALF in each lung were measured and compared between groups by Kruskal-Wallis test. Lung injury (increased wet/dry ratio, Prot-BALF, and TNF-alpha on endothelial and epithelial cells) was shown in the hyperventilated RLs with ZEEP compared with their corresponding CPAP LLs. PEEP prevented these injuries. Lung injury was also demonstrated in the recirculated LL compared with the nonrecirculated LL (Prot-BALF, TNF-alpha and interleukin-1beta [IL-1beta] mRNAs: the LL of the R-ZEEP is greater than the LL of NR-ZEEP by P < 0.01). Unilateral hyperventilated lungs with ZEEP induced TNF-alpha, increased permeability, and injured the control lung via perfusion. PMID:20403578

  4. Using ventilator graphics to identify patient-ventilator asynchrony.

    PubMed

    Nilsestuen, Jon O; Hargett, Kenneth D

    2005-02-01

    Patient-ventilator interaction can be described as the relationship between 2 respiratory pumps: (1) the patient's pulmonary system, which is controlled by the neuromuscular system and influenced by the mechanical characteristics of the lungs and thorax, and (2) the ventilator, which is controlled by the ventilator settings and the function of the flow valve. When the 2 pumps function in synchrony, every phase of the breath is perfectly matched. Anything that upsets the harmony between the 2 pumps results in asynchrony and causes patient discomfort and unnecessarily increases work of breathing. This article discusses asynchrony relative to the 4 phases of a breath and illustrates how asynchrony can be identified with the 3 standard ventilator waveforms: pressure, flow, and volume. The 4 phases of a breath are: (1) The trigger mechanism (ie, initiation of the inspiration), which is influenced by the trigger-sensitivity setting, patient effort, and valve responsiveness. (2) The inspiratory-flow phase. During both volume-controlled and pressure-controlled ventilation the patient's flow demand should be carefully evaluated, using the pressure and flow waveforms. (3) Breath termination (ie, the end of the inspiration). Ideally, the ventilator terminates inspiratory flow in synchrony with the patient's neural timing, but frequently the ventilator terminates inspiration either early or late, relative to the patient's neural timing. During volume-controlled ventilation we can adjust variables that affect inspiratory time (eg, peak flow, tidal volume). During pressure-controlled or pressure-support ventilation we can adjust variables that affect when the inspiration terminates (eg, inspiratory time, expiratory sensitivity). (4) Expiratory phase. Patients with obstructive lung disease are particularly prone to developing intrinsic positive end-expiratory pressure (auto-PEEP) and therefore have difficulty triggering the ventilator. Bedside evaluation for the presence of auto-PEEP should be routinely performed and corrective adjustments made when appropriate. PMID:15691392

  5. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. (1) All integral magazines shall be provided with natural or mechanical ventilation....

  6. Myocardial perfusion with rubidium-82. III. Theory relating severity of coronary stenosis to perfusion deficit

    SciTech Connect

    Mullani, N.A.

    1984-11-01

    The relation between the quantitative perfusion deficit, as measured by emission computerized tomography, and the severity of coronary artery stenosis is important for the noninvasive clinical evaluation of coronary artery disease in man. Positron emission tomography allows direct noninvasive measurement of myocardial perfusion and quantification of the size of the perfusion defect. Given this important imformation, a mathematical model has been derived to gauge the severity of a coronary stenosis from quantitative perfusion measurements in the normal and poststenotic regions of the heart. The theoretical basis is presented for relating regional myocardial perfusion and regional perfusion resistance to total, coronary blood flow and resistance at normal resting flow and during maximal coronary vasodilation. The concept of perfusion reserve is presented as a clinical measure of the severity of a stenosis.

  7. Autonomic imbalance: prophet of doom or scope for hope?

    PubMed Central

    Vinik, A I; Maser, R E; Ziegler, D

    2011-01-01

    It has long been recognized that cardiac autonomic neuropathy increases morbidity and mortality in diabetes and may have greater predictive power than traditional risk factors for cardiovascular events. Significant morbidity and mortality can now be attributable to autonomic imbalance between the sympathetic and parasympathetic nervous system regulation of cardiovascular function. New and emerging syndromes include orthostatic tachycardia, orthostatic bradycardia and an inability to use heart rate as a guide to exercise intensity because of the resting tachycardia. Recent studies have shown that autonomic imbalance may be a predictor of risk of sudden death with intensification of glycaemic control. This review examines an association of autonomic dysregulation and the role of inflammatory cytokines and adipocytokines that promote cardiovascular risk. In addition, conditions of autonomic imbalance associated with cardiovascular risk are discussed. Potential treatment for restoration of autonomic balance is outlined. PMID:21569084

  8. Transpired Air Collectors - Ventilation Preheating

    SciTech Connect

    Christensen, C.

    2006-06-22

    Many commercial and industrial buildings have high ventilation rates. Although all that fresh air is great for indoor air quality, heating it can be very expensive. This short (2-page) fact sheet describes a technology available to use solar energy to preheat ventilation air and dramatically reduce utility bills.

  9. Simultaneous Multiagent Hyperpolarized 13C Perfusion Imaging

    PubMed Central

    von Morze, Cornelius; Bok, Robert A.; Reed, Galen D.; Ardenkjaer-Larsen, Jan Henrik; Kurhanewicz, John; Vigneron, Daniel B.

    2014-01-01

    Purpose To demonstrate simultaneous hyperpolarization and imaging of three 13C-labeled perfusion MRI contrast agents with dissimilar molecular structures ([13C]urea, [13C]hydroxymethyl cyclopropane, and [13C]t-butanol) and correspondingly variable chemical shifts and physiological characteristics, and to exploit their varying diffusibility for simultaneous measurement of vascular permeability and perfusion in initial preclinical studies. Methods Rapid and efficient dynamic multislice imaging was enabled by a novel pulse sequence incorporating balanced steady state free precession excitation and spectral-spatial readout by multiband frequency encoding, designed for the wide, regular spectral separation of these compounds. We exploited the varying bilayer permeability of these tracers to quantify vascular permeability and perfusion parameters simultaneously, using perfusion modeling methods that were investigated in simulations. “Tripolarized” perfusion MRI methods were applied to initial preclinical studies with differential conditions of vascular permeability, in normal mouse tissues and advanced transgenic mouse prostate tumors. Results Dynamic imaging revealed clear differences among the individual tracer distributions. Computed permeability maps demonstrated differential permeability of brain tissue among the tracers, and tumor perfusion and permeability were both elevated over values expected for normal tissues. Conclusion Tripolarized perfusion MRI provides new molecular imaging measures for specifically monitoring permeability, perfusion, and transport simultaneously in vivo. PMID:24382698

  10. Ventilation of an hydrofoil wake

    NASA Astrophysics Data System (ADS)

    Arndt, Roger; Lee, Seung Jae; Monson, Garrett

    2013-11-01

    Ventilation physics plays a role in a variety of important engineering applications. For example, hydroturbine ventilation is used for control of vibration and cavitation erosion and more recently for improving the dissolved oxygen content of the flow through the turbine. The latter technology has been the focus of an ongoing study involving the ventilation of an hydrofoil wake to determine the velocity and size distribution of bubbles in a bubbly wake. This was carried out by utilizing particle shadow velocimetry (PSV). This technique is a non-scattering approach that relies on direct in-line volume illumination by a pulsed source such as a light-emitting diode (LED). The data are compared with previous studies of ventilated flow. The theoretical results of Hinze suggest that a scaling relationship is possible that can lead to developing appropriate design parameters for a ventilation system. Sponsored by ONR and DOE.

  11. Inhalation therapy in mechanical ventilation

    PubMed Central

    Maccari, Juçara Gasparetto; Teixeira, Cassiano; Gazzana, Marcelo Basso; Savi, Augusto; Dexheimer-Neto, Felippe Leopoldo; Knorst, Marli Maria

    2015-01-01

    Patients with obstructive lung disease often require ventilatory support via invasive or noninvasive mechanical ventilation, depending on the severity of the exacerbation. The use of inhaled bronchodilators can significantly reduce airway resistance, contributing to the improvement of respiratory mechanics and patient-ventilator synchrony. Although various studies have been published on this topic, little is known about the effectiveness of the bronchodilators routinely prescribed for patients on mechanical ventilation or about the deposition of those drugs throughout the lungs. The inhaled bronchodilators most commonly used in ICUs are beta adrenergic agonists and anticholinergics. Various factors might influence the effect of bronchodilators, including ventilation mode, position of the spacer in the circuit, tube size, formulation, drug dose, severity of the disease, and patient-ventilator synchrony. Knowledge of the pharmacological properties of bronchodilators and the appropriate techniques for their administration is fundamental to optimizing the treatment of these patients. PMID:26578139

  12. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

  13. Cardiac gated ventilation

    NASA Astrophysics Data System (ADS)

    Hanson, C. William, III; Hoffman, Eric A.

    1995-05-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. We evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50msec scan aperture. Multislice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. We observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a nonfailing model of the heart.

  14. Solar ventilation and tempering

    NASA Astrophysics Data System (ADS)

    Adámek, Karel; Pavlů, Miloš; Bandouch, Milan

    2014-08-01

    The paper presents basic information about solar panels, designed, realized and used for solar ventilation of rooms. Used method of numerical flow simulation gives good overview about warming and flowing of the air in several kinds of realized panels (window, facade, chimney). Yearlong measurements give a good base for calculations of economic return of invested capital. The operation of the system in transient period (spring, autumn) prolongs the period without classical heating of the room or building, in winter the classical heating is supported. In the summer period the system, furnished with chimney, can exhaust inner warm air together with necessary cooling of the system by gravity circulation, only. System needs not any invoiced energy source; it is supplied entirely by solar energy. Large building systems are supported by classical electric fan respectively.

  15. Addressing Gender Imbalance in Nigeria's Higher Education through Institutional Framework

    ERIC Educational Resources Information Center

    Okeke, Emeka Paul

    2013-01-01

    This paper examined the gender imbalance among students in Nigeria's higher education and the possible ways to addressing them. The poor access of female gender to higher education in Nigeria has become a thing of great concern to all stakeholders such as School authorities, Government, International agencies and employers of labor. The paper…

  16. Labor Markets in Imbalance: Review of Qualitative Evidence.

    ERIC Educational Resources Information Center

    Medoff, James L.; Wiener, Jonathan B.

    Recent statistical investigations indicate that labor market imbalance has increased during the past decade and has had important deleterious effects on the nation's inflation and productivity growth records. A growing difficulty in filling skilled jobs at a given unemployment rate is reflected. Business community analysts attribute the growing…

  17. THE ROLE OF INORGANIC ION IMBALANCE IN AQUATIC TOXICITY TESTING

    EPA Science Inventory

    Effluent toxicity testing methods have been well defined, but to a large part have not attempted to segregate the effects of active ionic concentrations and ion imbalances upon test and species performances. The role that various total dissolved solids in effluents have on regula...

  18. Building Decision Trees for the Multi-class Imbalance Problem

    E-print Network

    Chawla, Nitesh V.

    . In imbalanced datasets, the class of interest is generally a small fraction of the total instances attention. This is partially due to the fact that the multi-class imbal- ance problem is often much harder with decomposition techniques, outperform C4.4. 1 Introduction One of the fundamental problems in data mining

  19. Earth's Energy Imbalance KEVIN E. TRENBERTH AND JOHN T. FASULLO

    E-print Network

    Trenberth, Kevin Edward

    as a rise in ocean heat content (OHC). Data from the Ocean Reanalysis System, version 4 (ORAS4), and other among the rates of change of OHC, and do not resolve interannual variability adequately to capture ENSO). The natural variability of the energy imbalance is substantial from month to month, associated with cloud

  20. High frequency jet ventilation and intermittent positive pressure ventilation. Effect of cerebral blood flow in patients after open heart surgery

    SciTech Connect

    Pittet, J.F.; Forster, A.; Suter, P.M. )

    1990-02-01

    Attenuation of ventilator-synchronous pressure fluctuations of intracranial pressure has been demonstrated during high frequency ventilation in animal and human studies, but the consequences of this effect on cerebral blood flow have not been investigated in man. We compared the effects of high frequency jet ventilation and intermittent positive pressure ventilation on CBF in 24 patients investigated three hours after completion of open-heart surgery. The patients were investigated during three consecutive periods with standard sedation (morphine, pancuronium): a. IPPV; b. HFJV; c. IPPV. Partial pressure of arterial CO{sub 2} (PaCO{sub 2}: 4.5-5.5 kPa) and rectal temperature (35.5 to 37.5{degree}C) were maintained constant during the study. The CBF was measured by intravenous {sup 133}Xe washout technique. The following variables were derived from the cerebral clearance of {sup 133}Xe: the rapid compartment flow, the initial slope index, ie, a combination of the rapid and the slow compartment flows, and the ratio of fast compartment flow over total CBF (FF). Compared to IPPV, HFJV applied to result in the same mean airway pressure did not produce any change in pulmonary gas exchange, mean systemic arterial pressure, and cardiac index. Similarly, CBF was not significantly altered by HFJV. However, important variations of CBF values were observed in three patients, although the classic main determinants of CBF (PaCO{sub 2}, cerebral perfusion pressure, Paw, temperature) remained unchanged. Our results suggest that in patients with normal systemic hemodynamics, the effects of HFJV and IPPV on CBF are comparable at identical levels of mean airway pressure.

  1. Subsurface Ventilation System Description Document

    SciTech Connect

    2000-10-12

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  2. Subsurface Ventilation System Description Document

    SciTech Connect

    Eric Loros

    2001-07-25

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  3. Genomic imbalances in pediatric patients with chronic kidney disease

    PubMed Central

    Verbitsky, Miguel; Sanna-Cherchi, Simone; Fasel, David A.; Levy, Brynn; Kiryluk, Krzysztof; Wuttke, Matthias; Abraham, Alison G.; Kaskel, Frederick; Köttgen, Anna; Warady, Bradley A.; Furth, Susan L.; Wong, Craig S.; Gharavi, Ali G.

    2015-01-01

    BACKGROUND. There is frequent uncertainty in the identification of specific etiologies of chronic kidney disease (CKD) in children. Recent studies indicate that chromosomal microarrays can identify rare genomic imbalances that can clarify the etiology of neurodevelopmental and cardiac disorders in children; however, the contribution of unsuspected genomic imbalance to the incidence of pediatric CKD is unknown. METHODS. We performed chromosomal microarrays to detect genomic imbalances in children enrolled in the Chronic Kidney Disease in Children (CKiD) prospective cohort study, a longitudinal prospective multiethnic observational study of North American children with mild to moderate CKD. Patients with clinically detectable syndromic disease were excluded from evaluation. We compared 419 unrelated children enrolled in CKiD to multiethnic cohorts of 21,575 children and adults that had undergone microarray genotyping for studies unrelated to CKD. RESULTS. We identified diagnostic copy number disorders in 31 children with CKD (7.4% of the cohort). We detected 10 known pathogenic genomic disorders, including the 17q12 deletion HNF1 homeobox B (HNF1B) and triple X syndromes in 19 of 419 unrelated CKiD cases as compared with 98 of 21,575 control individuals (OR 10.8, P = 6.1 × 10–20). In an additional 12 CKiD cases, we identified 12 likely pathogenic genomic imbalances that would be considered reportable in a clinical setting. These genomic imbalances were evenly distributed among patients diagnosed with congenital and noncongenital forms of CKD. In the vast majority of these cases, the genomic lesion was unsuspected based on the clinical assessment and either reclassified the disease or provided information that might have triggered additional clinical care, such as evaluation for metabolic or neuropsychiatric disease. CONCLUSION. A substantial proportion of children with CKD have an unsuspected genomic imbalance, suggesting genomic disorders as a risk factor for common forms of pediatric nephropathy. Detection of pathogenic imbalances has practical implications for personalized diagnosis and health monitoring in this population. TRIAL REGISTRATION. ClinicalTrials.gov NCT00327860. FUNDING. This work was supported by the NIH, the National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK), the National Institute of Child Health and Human Development, and the National Heart, Lung, and Blood Institute. PMID:25893603

  4. 14 CFR 23.831 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Ventilation. 23.831 Section 23.831 Aeronautics...Cargo Accommodations § 23.831 Ventilation. (a) Each passenger and crew...adversely affect the ventilating air, the ventilation system must provide reasonable...

  5. 14 CFR 23.831 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Ventilation. 23.831 Section 23.831 Aeronautics...Cargo Accommodations § 23.831 Ventilation. (a) Each passenger and crew...adversely affect the ventilating air, the ventilation system must provide reasonable...

  6. Use of Adaptive Support Ventilation (ASV) in Ventilator Associated Pneumonia (VAP) - A Case Report

    PubMed Central

    Kath, Bipphy; Hemanth, N; Marella, Prashanti; Rao, M H

    2009-01-01

    Summary Prolonged ventilation leads to a higher incidence of ventilator associated pneumonia(VAP) resulting in ventilator dependency, increased costs and subsequent weaning failures. Prevention and aggressive treatment of VAP along with patient friendly newer modes of ventilation like adaptive support ventilation go a long way in successful management of these cases. PMID:20640145

  7. 6. VIEW LOOKING SOUTHEAST AT VENTILATION EQUIPMENT IN SOUTH VENTILATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW LOOKING SOUTHEAST AT VENTILATION EQUIPMENT IN SOUTH VENTILATION HOUSE. THIS AIR CONDITIONING SYSTEM WAS INSTALLED BY PARKS-CRAMER COMPANY OF FITCHBURG, MASSACHUSETTS WHEN THE MILL WAS CONSTRUCTED IN 1923-24. ONE AIR WASHER AND FAN ROOM EXTERIOR IS VISIBLE ON THE RIGHT. THE DUCTS FROM BOTH FAN ROOMS (CURVED METAL STRUCTURES AT CENTER AND LEFT OF PHOTO) ARE CONNECTED TO A COMMON AIR SHAFT. - Stark Mill, 117 Corinth Road, Hogansville, Troup County, GA

  8. Equivalence in Ventilation and Indoor Air Quality

    SciTech Connect

    Sherman, Max; Walker, Iain; Logue, Jennifer

    2011-08-01

    We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.

  9. Nozzle for discharging ventilation air from a ventilation system

    SciTech Connect

    Elfverson, S.E.

    1986-09-30

    This patent describes a nozzle for discharging ventilation air from a ventilation system, preferably arranged in a vehicle, including at least one outlet housing with a through-flow duct for ventilation air, a fixed plate transverse to the flow duct and rigidly attached to the outlet housing, and a plurality of plates parallel to the fixed plate. These plates are mutually displaceable in a direction transverse to the flow duct under the action of a control lever passing through the plates, the plates being formed with perforation patterns, which in coaction form ventilation ducts through which the ventilation air can flow and in response to the setting of the control lever cause deviation of the flow direction of the ventilation air. Each displaceable plate is formed with a grid cross comprising at least two intersecting bars, of which one bar has a substantially circular cross section, while the other bar has a substantially elliptical cross section and wherein the control lever is adapted to grip round a grid cross, the control lever having two pairs of longitudinal slots. One pair of the slots is adapted to grip without play one of the intersecting bars in each respective grid cross. The other pair of slots comprises a first slot adapted to grip without play the other of the intersecting bars, and a second slot formed with a width disabling engagement with the other of the intersecting bars.

  10. Literature Review of Displacement Ventilation 

    E-print Network

    Cho, S.; Im, P.; Haberl, J. S.

    2005-01-01

    Performance Evaluation and Design Guidelines for Displacement Ventilation” by Chen and Clicksman (2003), were used to begin the literature search. Their references include papers, articles, and web sites presenting major contributions to the understanding...

  11. Modeling of Tracer Transport Delays for Improved Quantification of Regional Pulmonary (18)F-FDG Kinetics, Vascular Transit Times, and Perfusion.

    PubMed

    Wellman, Tyler J; Winkler, Tilo; Vidal Melo, Marcos F

    2015-11-01

    (18)F-FDG-PET is increasingly used to assess pulmonary inflammatory cell activity. However, current models of pulmonary (18)F-FDG kinetics do not account for delays in (18)F-FDG transport between the plasma sampling site and the lungs. We developed a three-compartment model of (18)F-FDG kinetics that includes a delay between the right heart and the local capillary blood pool, and used this model to estimate regional pulmonary perfusion. We acquired dynamic (18)F-FDG scans in 12 mechanically ventilated sheep divided into control and lung injury groups (n = 6 each). The model was fit to tracer kinetics in three isogravitational regions-of-interest to estimate regional lung transport delays and regional perfusion. (13)NN bolus infusion scans were acquired during a period of apnea to measure regional perfusion using an established reference method. The delayed input function model improved description of (18)F-FDG kinetics (lower Akaike Information Criterion) in 98% of studied regions. Local transport delays ranged from 2.0 to 13.6 s, averaging 6.4 ± 2.9 s, and were highest in non-dependent regions. Estimates of regional perfusion derived from model parameters were highly correlated with perfusion measurements based on (13)NN-PET (R (2) = 0.92, p < 0.001). By incorporating local vascular transports delays, this model of pulmonary (18)F-FDG kinetics allows for simultaneous assessment of regional lung perfusion, transit times, and inflammation. PMID:25940652

  12. Water and Carbon as Creators of Imbalances in Nature

    NASA Astrophysics Data System (ADS)

    Shlafman, L. M.; Kontar, V. A.

    2012-12-01

    Our studies are showing that the carbon and water are closely intertwined. There are many reasons to study the imbalance of water and carbon together. For example, in photosynthesis six molecules of water and six molecules of carbon dioxide have created one molecule of sugar and six molecules of oxygen. 6H2O + 6CO2 go C6H12O6 + 6O2 For water and carbon dioxide, regarding the point of view of the imbalance, this process is the creator of imbalance of the decreasing type. The concentration of water and carbon dioxide in the atmosphere will decrease. For oxygen this process is the creator of imbalance of the increasing type. The concentration of oxygen in the atmosphere will increase. Water and carbon dioxide can be created independently of each other. For example, water is obtained from combining two hydrogen atoms and one oxygen atom: 2 H2 + O2 go 2 H2O Carbon dioxide also is possible to create without water: Na2CO3 go Na2O + CO2 or CaCO3 go CaO + CO2 But it is very often the water and carbon dioxide made up simultaneously in one reaction. For example combustion of methane gives carbon dioxide and water: CH4 + 2 O2 go CO2 + 2 H2O Carbon dioxide can come up more complicated way. Initially created carbon monoxide and water 2 CH4 + 3 O2 go 2 CO + 4 H2O After then the carbon monoxide rapidly oxidized to carbon dioxide. The gasification of solid fuels is the reaction: C + H20 go CO + H2 In the next step carbon monoxide is oxidized to carbon dioxide, and hydrogen is oxidized to water. C3H8 + 5 O2 go 3 CO2 + 4 H2O By the incomplete combustion of propane will be produced some very interesting components: 2 C3H8 + 7 O2 go 8 H2O + 2 CO2 + 2 CO + 2 C It will be water, carbon dioxide, carbon monoxide and pure carbon. Carbon monoxide will oxidize to carbon dioxide. But the pure carbon will have a very serious going on. By the incomplete combustion of not only propane, but other hydrocarbons, will be produced and the pure carbon also. This "pure carbon" or "black carbon" plays a very important role as the accelerator of the glaciers melting. The "black carbon" is one of the most important creators of the imbalance of water in Nature. More than a billion people of the world population are seriously dependent from the imbalances which create a "black carbon". There are many other processes of interaction between water and carbon, which creates imbalances of various types. We see that the imbalance of water and the imbalance of carbon sometimes can be controlled or at least, we would be prepared for unintended consequences.

  13. The effect of imbalance distribution and measurement locations on critical speeds in a turboprop engine rotor 

    E-print Network

    Marin, Manuel

    1996-01-01

    . This study examines the influence of imbalance distribution and vibration measurement location on critical speeds for a model turboprop engine rotor. Imbalance response measurements are presented for a full scale model mounted in rolling bearings with squeeze...

  14. Transtracheal ventilation in oral surgery.

    PubMed Central

    Layman, P. R.

    1983-01-01

    The use of transtracheal ventilation as a routine method of ventilation during anaesthesia for 60 patients with gross pathology requiring oral surgery is reported. Theoretical hazards of the technique and protection of the airway are discussed. There were no serious complications in this series. The technique is recommended as a simple and safe alternative to blind nasal intubation. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:6614769

  15. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Stopping Systems § 111.103-1 Power ventilation systems except machinery space...

  16. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Stopping Systems § 111.103-1 Power ventilation systems except machinery space...

  17. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Stopping Systems § 111.103-1 Power ventilation systems except machinery space...

  18. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Stopping Systems § 111.103-1 Power ventilation systems except machinery space...

  19. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Stopping Systems § 111.103-1 Power ventilation systems except machinery space...

  20. Brain perfusion imaging : performance and accuracy 

    E-print Network

    Zhu, Fan

    2013-07-02

    Brain perfusion weighted images acquired using dynamic contrast studies have an important clinical role in acute stroke diagnosis and treatment decisions. The purpose of my PhD research is to develop novel methodologies ...

  1. [New modifications in isolated extremity perfusion ].

    PubMed

    Aigner, K; Hild, P; Hundeiker, M

    1982-07-15

    Hyperthermic isolated extremity perfusion has been undertaken in 117 patients with advanced melanoma of the extremities from october 1979 to may 1981. Perfusion is indicated in cases above level III and tumor thickness above 1,5 mm. Among the cytostatic agents used were melphalane, melphalane and dactinomycin, nitrogen mustard/dactinomycin, as well as DTIC, cis-platinum and the combination of cis-platinum and dactinomycin. All cytostatics lead to tumor regression, as observed on tumors left in situ. Longterm results have yet to be awaited. While melphalane may be perfused at 42 degrees C, the cisplatinum perfused extremity should not be heated to above 40 degrees C because permanent neurological damage may be induced. For this reason maximal hyperthermia is reached before the cytostatic agent is introduced and has to be lowered when the drug is added. PMID:6889794

  2. Mechanical ventilation for severe asthma.

    PubMed

    Leatherman, James

    2015-06-01

    Acute exacerbations of asthma can lead to respiratory failure requiring ventilatory assistance. Noninvasive ventilation may prevent the need for endotracheal intubation in selected patients. For patients who are intubated and undergo mechanical ventilation, a strategy that prioritizes avoidance of ventilator-related complications over correction of hypercapnia was first proposed 30 years ago and has become the preferred approach. Excessive pulmonary hyperinflation is a major cause of hypotension and barotrauma. An appreciation of the key determinants of hyperinflation is essential to rational ventilator management. Standard therapy for patients with asthma undergoing mechanical ventilation consists of inhaled bronchodilators, corticosteroids, and drugs used to facilitate controlled hypoventilation. Nonconventional interventions such as heliox, general anesthesia, bronchoscopy, and extracorporeal life support have also been advocated for patients with fulminant asthma but are rarely necessary. Immediate mortality for patients who are mechanically ventilated for acute severe asthma is very low and is often associated with out-of-hospital cardiorespiratory arrest before intubation. However, patients who have been intubated for severe asthma are at increased risk for death from subsequent exacerbations and must be managed accordingly in the outpatient setting. PMID:26033128

  3. Ventilation Model and Analysis Report

    SciTech Connect

    V. Chipman

    2003-07-18

    This model and analysis report develops, validates, and implements a conceptual model for heat transfer in and around a ventilated emplacement drift. This conceptual model includes thermal radiation between the waste package and the drift wall, convection from the waste package and drift wall surfaces into the flowing air, and conduction in the surrounding host rock. These heat transfer processes are coupled and vary both temporally and spatially, so numerical and analytical methods are used to implement the mathematical equations which describe the conceptual model. These numerical and analytical methods predict the transient response of the system, at the drift scale, in terms of spatially varying temperatures and ventilation efficiencies. The ventilation efficiency describes the effectiveness of the ventilation process in removing radionuclide decay heat from the drift environment. An alternative conceptual model is also developed which evaluates the influence of water and water vapor mass transport on the ventilation efficiency. These effects are described using analytical methods which bound the contribution of latent heat to the system, quantify the effects of varying degrees of host rock saturation (and hence host rock thermal conductivity) on the ventilation efficiency, and evaluate the effects of vapor and enhanced vapor diffusion on the host rock thermal conductivity.

  4. Delimiting Allelic Imbalance of TYMS by Allele-Specific Analysis

    PubMed Central

    Balboa-Beltrán, Emilia; Cruz, Raquel; Carracedo, Angel; Barros, Francisco

    2015-01-01

    Abstract Allelic imbalance of thymidylate synthase (TYMS) is attributed to polymorphisms in the 5?- and 3?-untranslated region (UTR). These polymorphisms have been related to the risk of suffering different cancers, for example leukemia, breast or gastric cancer, and response to different drugs, among which are methotrexate glutamates, stavudine, and specifically 5-fluorouracil (5-FU), as TYMS is its direct target. A vast literature has been published in relation to 5-FU, even suggesting the sole use of these polymorphisms to effectively manage 5-FU dosage. Estimates of the extent to which these polymorphisms influence in TYMS expression have in the past been based on functional analysis by luciferase assays and quantification of TYMS mRNA, but both these studies, as the association studies with cancer risk or with toxicity or response to 5-FU, are very contradictory. Regarding functional assays, the artificial genetic environment created in luciferase assay and the problems derived from quantitative polymerase chain reactions (qPCRs), for example the use of a reference gene, may have distorted the results. To avoid these sources of interference, we have analyzed the allelic imbalance of TYMS by allelic-specific analysis in peripheral blood mononuclear cells (PBMCs) from patients. Allelic imbalance in PBMCs, taken from 40 patients with suspected myeloproliferative haematological diseases, was determined by fluorescent fragment analysis (for the 3?-UTR polymorphism), Sanger sequencing and allelic-specific qPCR in multiplex (for the 5?-UTR polymorphisms). For neither the 3?- nor the 5?-UTR polymorphisms did the observed allelic imbalance exceed 1.5 fold. None of the TYMS polymorphisms is statistically associated with allelic imbalance. The results acquired allow us to deny the previously established assertion of an influence of 2 to 4 fold of the rs45445694 and rs2853542 polymorphisms in the expression of TYMS and narrow its allelic imbalance to 1.5 fold, in our population. These data circumscribe the influence of these polymorphisms in the clinical outcome of 5-FU and question their use for establishing 5-FU dosage, above all when additional genetic factors are not considered. PMID:26166093

  5. Vicarious Audiovisual Learning in Perfusion Education

    PubMed Central

    Rath, Thomas E.; Holt, David W.

    2010-01-01

    Abstract: Perfusion technology is a mechanical and visual science traditionally taught with didactic instruction combined with clinical experience. It is difficult to provide perfusion students the opportunity to experience difficult clinical situations, set up complex perfusion equipment, or observe corrective measures taken during catastrophic events because of patient safety concerns. Although high fidelity simulators offer exciting opportunities for future perfusion training, we explore the use of a less costly low fidelity form of simulation instruction, vicarious audiovisual learning. Two low fidelity modes of instruction; description with text and a vicarious, first person audiovisual production depicting the same content were compared. Students (n = 37) sampled from five North American perfusion schools were prospectively randomized to one of two online learning modules, text or video. These modules described the setup and operation of the MAQUET ROTAFLOW standalone centrifugal console and pump. Using a 10 question multiple-choice test, students were assessed immediately after viewing the module (test #1) and then again 2 weeks later (test #2) to determine cognition and recall of the module content. In addition, students completed a questionnaire assessing the learning preferences of today’s perfusion student. Mean test scores from test #1 for video learners (n = 18) were significantly higher (88.89%) than for text learners (n = 19) (74.74%), (p < .05). The same was true for test #2 where video learners (n = 10) had an average score of 77% while text learners (n = 9) scored 60% (p < .05). Survey results indicated video learners were more satisfied with their learning module than text learners. Vicarious audiovisual learning modules may be an efficacious, low cost means of delivering perfusion training on subjects such as equipment setup and operation. Video learning appears to improve cognition and retention of learned content and may play an important role in how we teach perfusion in the future, as simulation technology becomes more prevalent. PMID:21313929

  6. Improved exercise myocardial perfusion during lidoflazine therapy

    SciTech Connect

    Shapiro, W.; Narahara, K.A.; Park, J.

    1983-11-01

    Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a study of 6 patients with severe classic angina pectoris, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise.

  7. Pancreas transplants: Evaluation using perfusion scintigraphy

    SciTech Connect

    Kuni, C.C.; du Cret, R.P.; Boudreau, R.J.

    1989-07-01

    To determine the value of scintigraphic perfusion studies in evaluating pancreas transplant patients, we reviewed 56 of these studies in 22 patients who had 27 transplants. Seventeen patients underwent two or more studies. The perfusion studies were performed with 20 mCi (740 MBq) of 99mTc-DTPA injected as a bolus followed by eight to 16 serial 2-sec images and a 500,000-count immediate static image. Images were evaluated for (1) the time and intensity of pancreatic peak radioactivity relative to the time and intensity of the iliac arterial peak; (2) relative pancreatic to iliac arterial intensity on the static image; and (3) size, homogeneity, and definition of the pancreas. Clinical diagnoses at the time of scintigraphy of normal function (n = 36), rejection (n = 13), pancreatitis (n = 6), or arterial thrombosis (n = 1) were based on insulin requirement, urine amylase, serum glucose, serum amylase, response to therapy, cultures, CT, MR, sonography, scintigraphy with 67Ga or 111In-WBCs, percutaneous drainage results, angiography, surgery, and pathologic examination of resected transplants. Three 99mTc-DTPA perfusion studies showed no pancreatic perfusion, four showed decreasing perfusion on serial studies, and five showed progressive loss of definition of the pancreas on serial studies. Of the three patients with no detectable perfusion, one had a normally functioning transplant, one had arterial thrombosis with transplant infarction, and one had severe rejection with minimal function. Decreasing perfusion was associated with rejection in three patients and pancreatitis in one. Decreasing definition was seen in four patients with rejection and one with pancreatitis. We conclude that perfusion scintigraphy is useful, primarily when performed serially, although nonspecific for evaluating pancreas transplants.

  8. Cyclooxygenase blockade (COB) attenuates ethanol-induced pulmonary vasoconstriction in perfused rat lungs

    SciTech Connect

    Drummond, W.H.; Lyles, D. )

    1990-02-26

    Ethanol causes pulmonary vasoconstriction and vascular leak by obscure mechanisms. In lambs, COB with indomethacin (Indo) or meclofenamate (Meclo) block ethanol's circulatory effects. To test for these effects in rats, in-situ, ventilated, Krebs-Henselheit perfused (constant flow) lungs were studied in 6 groups: ethanol (ETOH) and perfusate controls; ETOH/Meclo, 0.5 and 1 mg/kg, IV; ETOH/Indo, 0.5 and 1 mg/kg, IV, given 30 minutes before study. They measured mean pulmonary arterial pressure (PAP), peak inspiratory pressure (PIP) and edema, indexed by reservoir weight change (RW), then by tracheal froth ( death'). ETOH doses (0.5, 1.3 and 2.2gm) were infused into the perfusate (60 ml). Data were analyzed by ANOVA and X{sup 2}; n = 9 in each group. PAP differed by treatment, by drug/dose, and by dose/treatment interactions; PIP, RW change, and death' were attenuated. Data show that COB lessens the vascular and edema effects of moderate dose ETOH, which larger ETOH doses override.

  9. Site of pulmonary vasodilation by inhaled nitric oxide in the perfused lung

    SciTech Connect

    Rimar, S.; Gillis, C.N.

    1995-05-01

    Site of pulmonary vasodilation by inhaled nitric oxide in the perfused lung. To determine the site of inhaled nitric oxide (NO)-induced pulmonary vasodilation, a double vascular occlusion technique was used with rabbit lungs ventilated and perfused at 20 ml/min with Krebs solution containing 3% dextran and 30 {mu}M indomethacin. Inhaled NO (120 ppm for 3% min) reduced pulmonary vasoconstriction produced by U-46619 infusion (0.5 -1.2 nmol/min), significantly decreasing total resistance (RT) [1,080 {plus_minus} 51 (SE) vs. 1,545 {plus_minus} 109 mmHg-min/l; P < 0.01]. Acetylcholine infusion (ACh; 2-5 nmol/min) and nitroglycerin (NTG; 0.35 {mu}mol) likewise decreased RT. Arterial resistance (Ra) was also significantly less with inhaled NO, ACh, and NTG compared with U-46619 alone. Venous resistance (Rv), however, was unchanged. When the direction of perfusion was reversed in the lung, inhaled NO, ACh, and NTG significantly decreased RT compared with U-46619 alone, and Rv was also reduced by all three agents. After electrolysis-induced acute lung injury, inhaled NO significantly reduced both RT and Ra compared with U-46619 alone, whereas Rv was unaffected. Our results demonstrate that inhaled NO gas affects primarily the arterial (precapillary) component of the pulmonary circulation but, under conditions of extreme venous constriction, may dilate the postcapillary component as well. 25 refs., 4 figs.

  10. 21 CFR 868.5955 - Intermittent mandatory ventilation attachment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... false Intermittent mandatory ventilation attachment. 868.5955 Section...5955 Intermittent mandatory ventilation attachment. (a) Identification. An intermittent mandatory ventilation (IMV) attachment is a...

  11. 21 CFR 868.5955 - Intermittent mandatory ventilation attachment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... false Intermittent mandatory ventilation attachment. 868.5955 Section...5955 Intermittent mandatory ventilation attachment. (a) Identification. An intermittent mandatory ventilation (IMV) attachment is a...

  12. 21 CFR 868.5955 - Intermittent mandatory ventilation attachment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... false Intermittent mandatory ventilation attachment. 868.5955 Section...5955 Intermittent mandatory ventilation attachment. (a) Identification. An intermittent mandatory ventilation (IMV) attachment is a...

  13. 21 CFR 868.5955 - Intermittent mandatory ventilation attachment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... false Intermittent mandatory ventilation attachment. 868.5955 Section...5955 Intermittent mandatory ventilation attachment. (a) Identification. An intermittent mandatory ventilation (IMV) attachment is a...

  14. 21 CFR 868.5955 - Intermittent mandatory ventilation attachment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... false Intermittent mandatory ventilation attachment. 868.5955 Section...5955 Intermittent mandatory ventilation attachment. (a) Identification. An intermittent mandatory ventilation (IMV) attachment is a...

  15. Perfusion visualization and analysis for pulmonary embolism

    NASA Astrophysics Data System (ADS)

    Vaz, Michael S.; Kiraly, Atilla P.; Naidich, David P.; Novak, Carol L.

    2005-04-01

    Given the nature of pulmonary embolism (PE), timely and accurate diagnosis is critical. Contrast enhanced high-resolution CT images allow physicians to accurately identify segmental and sub-segmental emboli. However, it is also important to assess the effect of such emboli on the blood flow in the lungs. Expanding upon previous research, we propose a method for 3D visualization of lung perfusion. The proposed method allows users to examine perfusion throughout the entire lung volume at a single glance, with areas of diminished perfusion highlighted so that they are visible independent of the viewing location. This may be particularly valuable for better accuracy in assessing the extent of hemodynamic alterations resulting from pulmonary emboli. The method also facilitates user interaction and may help identify small peripheral sub-segmental emboli otherwise overlooked. 19 patients referred for possible PE were evaluated by CT following the administration of IV contrast media. An experienced thoracic radiologist assessed the 19 datasets with 17 diagnosed as being positive for PE with multiple emboli. Since anomalies in lung perfusion due to PE can alter the distribution of parenchymal densities, we analyzed features collected from histograms of the computed perfusion maps and demonstrate their potential usefulness as a preliminary test to suggest the presence of PE. These histogram features also offer the possibility of distinguishing distinct patterns associated with chronic PE and may even be useful for further characterization of changes in perfusion or overall density resulting from associated conditions such as pneumonia or diffuse lung disease.

  16. Species Distribution Modeling and Prediction: A Class Imbalance Problem Reid A. Johnson

    E-print Network

    Chawla, Nitesh V.

    Species Distribution Modeling and Prediction: A Class Imbalance Problem Reid A. Johnson Dept-occurrences, we approach the modeling of species' distributions with a focus on the problem of class imbalance to address the problems of class imbalance, but which have rarely or never been applied to the domain

  17. ADAPTIVE COMPENSATION OF FREQUENCY SELECTIVE IQ IMBALANCE AND CARRIER FREQUENCY OFFSET FOR OFDM BASED RECEIVERS

    E-print Network

    . Along with IQ imbalance, OFDM systems are also very sensitive to car- rier frequency offset (CFO). The performance degradation due to receiver IQ imbalance and CFO in OFDM systems has been inves- tigated in [6]-[8]. Joint compensation algorithm for frequency inde- pendent IQ imbalance and CFO has been developed in [9

  18. JOINT COMPENSATION OF CARRIER FREQUENCY OFFSET AND FREQUENCY SELECTIVE IQ IMBALANCE FOR OFDM BASED RECEIVERS

    E-print Network

    to Carrier Frequency Offset (CFO). The performance degra- dation due to receiver IQ imbalance and CFO in OFDM independent IQ imbalance and CFO has been developed in [7]. In [8], a time domain compensation for frequency selective IQ imbalance and CFO is proposed. This time domain solution equalizes all tones in a combined

  19. JOINT COMPENSATION OF OFDM TRANSMITTER AND RECEIVER IQ IMBALANCE IN THE PRESENCE OF CARRIER FREQUENCY OFFSET

    E-print Network

    Offset (CFO). The performance degradation due to receiver IQ imbalance and CFO on OFDM systems have been with CFO estimation and compensation. While the combination of CFO with receiver IQ imbalance has been for the complete problem combining CFO with both transmitter and receiver IQ imbal- ance. This report is organized

  20. Different nutritional states and autonomic imbalance in childhood.

    PubMed

    Dippacher, S; Willaschek, C; Buchhorn, R

    2014-11-01

    Autonomic imbalance, measured as heart rate variability (HRV), and an increased cardiovascular risk are described for overweight children, as well as for patients with anorexia nervosa. We investigate whether body mass index or actual caloric intake influences HRV. In our cross-sectional study, we compared HRV parameters for a healthy control group (n=52), anorexia nervosa patients (n=17), thin (n=18) and overweight children (n=19). Anorexia nervosa patients showed significantly lower heart rates at night (P<0.001) and significantly higher SDNN (standard deviation of all RR-intervals) (P<0.001 ), whereas overweight children showed an opposing pattern. SDNN and heart rate at night are highly correlated (r=0.89, R(2)=0.79, P<0.001). We conclude that not current body mass index but caloric intake determines HRV. Obesity and anorexia nervosa are characterized by a specific pattern of autonomic imbalance. PMID:25248356

  1. Vorticity imbalance and stability in relation to convection

    NASA Technical Reports Server (NTRS)

    Read, W. L.; Scoggins, J. R.

    1977-01-01

    A complete synoptic-scale vorticity budget was related to convection storm development in the eastern two-thirds of the United States. The 3-h sounding interval permitted a study of time changes of the vorticity budget in areas of convective storms. Results of analyses revealed significant changes in values of terms in the vorticity equation at different stages of squall line development. Average budgets for all areas of convection indicate systematic imbalance in the terms in the vorticity equation. This imbalance resulted primarily from sub-grid scale processes. Potential instability in the lower troposphere was analyzed in relation to the development of convective activity. Instability was related to areas of convection; however, instability alone was inadequate for forecast purposes. Combinations of stability and terms in the vorticity equation in the form of indices succeeded in depicting areas of convection better than any one item separately.

  2. Order imbalance and stock returns: Evidence from China

    E-print Network

    Shenoy, Catherine

    2007-01-01

    became available to selected foreign investors in 2005. In this paper, we study A shares only. There is some evidence to suggest that the primary market participants in the A share markets are individuals. The Shanghai Stock Exchange reports 37.9 million..., institution vs. retail. These authors find support for both herding and order splitting explanations of serially correlated order imbalances. Theoretical models developed by Ho and Stoll (1981) and Spiegel and Subrahmanyam (1995) predict prolonged pricing...

  3. Money and age in schools: Bullying and power imbalances.

    PubMed

    Chaux, Enrique; Castellanos, Melisa

    2014-09-12

    School bullying continues to be a serious problem around the world. Thus, it seems crucial to clearly identify the risk factors associated with being a victim or a bully. The current study focused in particular on the role that age and socio-economic differences between classmates could play on bullying. Logistic and multilevel analyses were conducted using data from 53,316 5th and 9th grade students from a representative sample of public and private Colombian schools. Higher age and better family socio-economic conditions than classmates were risk factors associated with being a bully, while younger age and poorer socio-economic conditions than classmates were associated with being a victim of bullying. Coming from authoritarian families or violent neighborhoods, and supporting beliefs legitimizing aggression, were also associated with bullying and victimization. Empathy was negatively associated with being a bully, and in some cases positively associated with being a victim. The results highlight the need to take into account possible sources of power imbalances, such as age and socio-economic differences among classmates, when seeking to prevent bullying. In particular, interventions focused on peer group dynamics might contribute to avoid power imbalances or to prevent power imbalances from becoming power abuse. Aggr. Behav. 9999:XX-XX, 2014. © 2014 Wiley Periodicals, Inc. PMID:25219327

  4. Effects of Steroid Hormones on Sex Differences in Cerebral Perfusion

    PubMed Central

    Ghisleni, Carmen; Bollmann, Steffen; Biason-Lauber, Anna; Poil, Simon-Shlomo; Brandeis, Daniel; Martin, Ernst; Michels, Lars; Hersberger, Martin; Suckling, John

    2015-01-01

    Sex differences in the brain appear to play an important role in the prevalence and progression of various neuropsychiatric disorders, but to date little is known about the cerebral mechanisms underlying these differences. One widely reported finding is that women demonstrate higher cerebral perfusion than men, but the underlying cause of this difference in perfusion is not known. This study investigated the putative role of steroid hormones such as oestradiol, testosterone, and dehydroepiandrosterone sulphate (DHEAS) as underlying factors influencing cerebral perfusion. We acquired arterial spin labelling perfusion images of 36 healthy adult subjects (16 men, 20 women). Analyses on average whole brain perfusion levels included a multiple regression analysis to test for the relative impact of each hormone on the global perfusion. Additionally, voxel-based analyses were performed to investigate the sex difference in regional perfusion as well as the correlations between local perfusion and serum oestradiol, testosterone, and DHEAS concentrations. Our results replicated the known sex difference in perfusion, with women showing significantly higher global and regional perfusion. For the global perfusion, DHEAS was the only significant predictor amongst the steroid hormones, showing a strong negative correlation with cerebral perfusion. The voxel-based analyses revealed modest sex-dependent correlations between local perfusion and testosterone, in addition to a strong modulatory effect of DHEAS in cortical, subcortical, and cerebellar regions. We conclude that DHEAS in particular may play an important role as an underlying factor driving the difference in cerebral perfusion between men and women. PMID:26356576

  5. The effect of CO sub 2 on pulmonary artery pressure (P sub pa ) over time in the isolated perfused rabbit lung

    SciTech Connect

    Reynolds, P.; Shayevitz, J. )

    1991-03-11

    The isolated perfused rabbit lung model is used in studies of pulmonary hemodynamics, structure, and function under conditions closely resembling those which occur in living animals. The purpose of this study is to observe changes in P{sub pa} in response to differing concentrations of CO{sub 2} over time. After rapid exsanguination a tracheostomy was performed. Cannulas were secured in the main pulmonary artery and the left atrium. The lungs were perfused with Krebs-Henseleit buffer mixed with blood at a rate of 120 ml/min with recirculation. The temperature of the perfusate was maintained between 35 and 38C. The lungs were then ventilated with 5% CO{sub 2} in air with a tidal volume of 10 ml/kg at 20 breaths/min. CO{sub 2} was altered randomly by ventilating the lungs 2, 5 or 10% CO{sub 2} in air. Metabolic acidosis was corrected with NaHCO{sub 3}. In the first two hour period after lung perfusion was begun, the model was allowed to stabilize at each CO{sub 2} concentration, and pH, pCO{sub 2}, pO{sub 2}, and base excess were determined at each P{sub pa}. All measurements were repeated in the second period beginning two hours after lung perfusion was started. P{sub pa} was plotted against pH for each animal in both early and late phases, and simple regression analysis was performed. The slopes and the y intercepts for the data sets in both groups were compared using one factor ANOVA, and were found to be significantly different, implying a statistical difference between regression lines. In the early phase this model behaves like the in vivo lung, i.e. hypercarbia appears to increase, while hypocarbia decreases, P{sub pa}. During the late phase of lung perfusion the opposite occurs.

  6. Musculoskeletal pain and effort-reward imbalance- a systematic review

    PubMed Central

    2014-01-01

    Background Musculoskeletal pain may be triggered by physical strains and psychosocial risk factors. The effort-reward imbalance model (ERI model) is a stress model which measures psychosocial factors in the working world. The question is whether workers with an effort-reward imbalance report musculoskeletal pain more frequently than those with no effort-reward imbalance. A systematic review using a best evidence synthesis approach was conducted to answer this question. Methods A literature search was conducted for the period from 1996 to 2012, using three databases (Pubmed, Embase and PsycINFO). The research criteria related to psychosocial, work-related stress as per the ERI model and to musculoskeletal pain. A quality score was developed using various quality criteria to assess the standard of the studies. The level of evidence was graded as in (Am J Ind Med 39:180–193, 2001). Results After applying the inclusion criteria, a total of 19 studies were included in the review: 15 cross-sectional studies, three prospective studies and one case–control study. 74% of all studies exhibited good methodological quality, 53% collected data using the original ERI questionnaire, and in 42% of the studies, there was adequate control for physical working conditions. Furthermore, different cut-off points were used to classify exposed and non-exposed individuals. On the basis of 13 studies with a positive, statistically significant association, a moderate level of evidence was inferred for the association between effort-reward imbalance and musculoskeletal pain. The evidence for a role of over-commitment and for its interaction with effort-reward imbalance was rated as inconclusive - on the basis of eight and five studies, respectively. Conclusions On the basis of the available evidence, no reliable conclusion may be drawn about any association between the psychosocial factors ascertained using the ERI model and musculoskeletal pain. Before a reliable statement can be made on the association between ERI and musculoskeletal pain, additional longitudinal studies must be performed - with a standardised method for recording and classifying exposure, as well as control of physical confounders. Appropriate preventive measures can then be specified. PMID:24428955

  7. Residential ventilation standards scoping study

    SciTech Connect

    McKone, Thomas E.; Sherman, Max H.

    2003-10-01

    The goals of this scoping study are to identify research needed to develop improved ventilation standards for California's Title 24 Building Energy Efficiency Standards. The 2008 Title 24 Standards are the primary target for the outcome of this research, but this scoping study is not limited to that timeframe. We prepared this scoping study to provide the California Energy Commission with broad and flexible options for developing a research plan to advance the standards. This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the ventilation needs of California residences, determining the bases for setting residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and corresponding levels of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  8. 33 CFR 183.620 - Natural ventilation system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Natural ventilation system. 183.620 Section...Ventilation § 183.620 Natural ventilation system. (a) Except for...open to the atmosphere, a natural ventilation system that meets the...

  9. 30 CFR 57.8532 - Opening and closing ventilation doors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Opening and closing ventilation doors. 57.8532 Section 57...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8532 Opening and closing ventilation doors. When ventilation...

  10. 30 CFR 57.8532 - Opening and closing ventilation doors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Opening and closing ventilation doors. 57.8532 Section 57...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8532 Opening and closing ventilation doors. When ventilation...

  11. 30 CFR 57.8532 - Opening and closing ventilation doors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Opening and closing ventilation doors. 57.8532 Section 57...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8532 Opening and closing ventilation doors. When ventilation...

  12. 30 CFR 57.8532 - Opening and closing ventilation doors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Opening and closing ventilation doors. 57.8532 Section 57...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8532 Opening and closing ventilation doors. When ventilation...

  13. 30 CFR 57.8532 - Opening and closing ventilation doors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Opening and closing ventilation doors. 57.8532 Section 57...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8532 Opening and closing ventilation doors. When ventilation...

  14. A microprocessor-controlled tracheal insufflation-assisted total liquid ventilation system.

    PubMed

    Parker, James Courtney; Sakla, Adel; Donovan, Francis M; Beam, David; Chekuri, Annu; Al-Khatib, Mohammad; Hamm, Charles R; Eyal, Fabien G

    2009-09-01

    A prototype time cycled, constant volume, closed circuit perfluorocarbon (PFC) total liquid ventilator system is described. The system utilizes microcontroller-driven display and master control boards, gear motor pumps, and three-way solenoid valves to direct flow. A constant tidal volume and functional residual capacity (FRC) are maintained with feedback control using end-expiratory and end-inspiratory stop-flow pressures. The system can also provide a unique continuous perfusion (bias flow, tracheal insufflation) through one lumen of a double-lumen endotracheal catheter to increase washout of dead space liquid. FRC and arterial blood gases were maintained during ventilation with Rimar 101 PFC over 2-3 h in normal piglets and piglets with simulated pulmonary edema induced by instillation of albumin solution. Addition of tracheal insufflation flow significantly improved the blood gases and enhanced clearance of instilled albumin solution during simulated edema. PMID:19629555

  15. Pulmonary Perfusion and Xenon Gas Exchange in Rats: MR Imaging with Intravenous Injection of Hyperpolarized 129Xe1

    PubMed Central

    Driehuys, Bastiaan; Möller, Harald E.; Cleveland, Zackary I.; Pollaro, James; Hedlund, Laurence W.

    2009-01-01

    Purpose: To develop and demonstrate a method for regional evaluation of pulmonary perfusion and gas exchange based on intravenous injection of hyperpolarized xenon 129 (129Xe) and subsequent magnetic resonance (MR) imaging of the gas-phase 129Xe emerging in the alveolar airspaces. Materials and Methods: Five Fischer 344 rats that weighed 200—425 g were prepared for imaging according to an institutional animal care and use committee—approved protocol. Rats were ventilated, and a 3-F catheter was placed in the jugular (n = 1) or a 24-gauge catheter in the tail (n = 4) vein. Imaging and spectroscopy of gas-phase 129Xe were performed after injecting 5 mL of half-normal saline saturated with 129Xe hyperpolarized to 12%. Corresponding ventilation images were obtained during conventional inhalation delivery of hyperpolarized 129Xe. Results: Injections of 129Xe-saturated saline were well tolerated and produced a strong gas-phase 129Xe signal in the airspaces that resulted from 129Xe transport through the pulmonary circulation and diffusion across the blood-gas barrier. After a single injection, the emerging 129Xe gas could be detected separately from 129Xe remaining in the blood and was imaged with an in-plane resolution of 1 × 1 mm and a signal-to-noise ratio of 25. Images in one rat revealed a matched ventilation-perfusion deficit, while images in another rat showed that xenon gas exchange was temporarily impaired after saline overload, with recovery of function 1 hour later. Conclusion: MR imaging of gas-phase 129Xe emerging in the pulmonary airspaces after intravenous injection has the potential to become a sensitive and minimally invasive new tool for regional evaluation of pulmonary perfusion and gas exchange. Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/2513081550/DC1 PMID:19703880

  16. Human versus Computer Controlled Selection of Ventilator Settings: An Evaluation of Adaptive Support Ventilation and Mid-Frequency Ventilation

    PubMed Central

    Mireles-Cabodevila, Eduardo; Diaz-Guzman, Enrique; Arroliga, Alejandro C.; Chatburn, Robert L.

    2012-01-01

    Background. There are modes of mechanical ventilation that can select ventilator settings with computer controlled algorithms (targeting schemes). Two examples are adaptive support ventilation (ASV) and mid-frequency ventilation (MFV). We studied how different clinician-chosen ventilator settings are from these computer algorithms under different scenarios. Methods. A survey of critical care clinicians provided reference ventilator settings for a 70?kg paralyzed patient in five clinical/physiological scenarios. The survey-derived values for minute ventilation and minute alveolar ventilation were used as goals for ASV and MFV, respectively. A lung simulator programmed with each scenario's respiratory system characteristics was ventilated using the clinician, ASV, and MFV settings. Results. Tidal volumes ranged from 6.1 to 8.3?mL/kg for the clinician, 6.7 to 11.9?mL/kg for ASV, and 3.5 to 9.9?mL/kg for MFV. Inspiratory pressures were lower for ASV and MFV. Clinician-selected tidal volumes were similar to the ASV settings for all scenarios except for asthma, in which the tidal volumes were larger for ASV and MFV. MFV delivered the same alveolar minute ventilation with higher end expiratory and lower end inspiratory volumes. Conclusions. There are differences and similarities among initial ventilator settings selected by humans and computers for various clinical scenarios. The ventilation outcomes are the result of the lung physiological characteristics and their interaction with the targeting scheme. PMID:23119152

  17. Radionuclide cerebral perfusion imaging: Normal pattern

    SciTech Connect

    Goldsmith, S.J.; Stritzke, P.; Losonczy, M.; Vallabhajosula, S.; Holan, V.; DaCosta, M.; Muzinic, M.

    1991-12-31

    Regional cerebral perfusion imaging using a new class of {sup 99m}Tc and {sup 123}I labeled compounds which traverse the blood brain barrier and SPECT imaging technology provides an opportunity to assess this physiologic phenomenon during normal cerebral function and as a manifestation of disease in the central nervous system disease. These applications pose a challenge to the nuclear medicine physician for several reasons: (a) the complex and somewhat unfamiliar functional anatomy, (b) the marked regional differences in regional cerebral perfusion at rest, (c) the lack of understanding of the effect of variations in ambient conditions on regional cerebral perfusion. The difficulties in interpretation are augmented by the display itself. There is frequently no difficulty in differentiating between gray and white matter. However, the frequently used {open_quotes}hot body{close_quotes} color maps, introduce a good deal of contrast, producing displays with apparent interruption in regional cortical perfusion whereas black and white displays provide minimal contrast in the regional cortical activity. The authors sought to define how much variation in regional cerebral perfusion is {open_quotes}allowed{close_quotes} under controlled conditions, to establish a basis to interpret if changes in the environment, psychological interventions, or disease states are accompanied by a measurable change. 2 figs., 1 tab.

  18. Heating, Ventilation, and Air Conditioning Design

    E-print Network

    .................................................................................................5 3 HVAC Design and Implementation ...............Heating, Ventilation, and Air Conditioning Design Strategy for a Hot-Humid Production Builder P% postconsumer waste #12;iii Heating, Ventilation, and Air Conditioning Design Strategy for a Hot

  19. Energy Recovery Ventilator Membrane Efficiency Testing 

    E-print Network

    Rees, Jennifer Anne

    2013-05-07

    A test setup was designed and built to test energy recovery ventilator membranes. The purpose of this test setup was to measure the heat transfer and water vapor transfer rates through energy recover ventilator membranes and find their effectiveness...

  20. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... with the controls for every power ventilation system to which this section is applicable; and (b)...

  1. We compared the efficacy of positive pressure ventilation (PPV) vs negative pressure ventilation (NPV) in providing

    E-print Network

    Shadmehr, Reza

    We compared the efficacy of positive pressure ventilation (PPV) vs negative pressure ventilationEMG), minute ventilation (VE),tidal volume (VT), and end-tidal CO (etCOÃ during 15 minutes of PPV and NPV. For each subject, ventilator adjustments were made to obtain VE similar to levels measured during quiet

  2. Fracture ventilation by surface winds

    NASA Astrophysics Data System (ADS)

    Nachshon, U.; Dragila, M. I.; Weisbrod, N.

    2011-12-01

    Gas exchange between the Earth subsurface and the atmosphere is an important mechanism, affecting hydrological, agricultural and environmental processes. From a hydrological aspect, water vapor transport is the most important process related to Earth-atmosphere gas exchange. In respect to agriculture, gas transport in the upper soil profile is important for soil aeration. From an environmental aspect, emission of volatile radionuclides, such as 3H, 14C and Rd from radioactive waste disposal facilities; volatile organic components from industrial sources and Rn from natural sources, all found in the upper vadose zone, can greatly affect public health when emissions occur in populated areas. Thus, it is vital to better understand gas exchange processes between the Earth's upper crust and atmosphere. Four major mechanisms are known to transfer gases between ground surface and atmosphere: (1) Diffusion; (2) Pressure gradients between ground pores and atmosphere due to changes in barometric pressure; (3) Density-driven gas flow in respond to thermal gradients in the ground; and (4) Winds above the ground surface. Herein, the wind ventilation mechanism is studied. Whereas the wind's impact on ground ventilation was explored in several studies, the physical mechanisms governing this process were hardly quantified or characterized. In this work the physical properties of fracture ventilation due to wind blowing along land surface were explored and quantified. Both field measurements and Hele-Shaw experiments under controlled conditions in the laboratory were used to study this process. It was found that winds in the range of 0.3 m/s result in fracture ventilation down to a depth of 0.2 m. As wind velocity increases, the depth of the ventilation inside the fracture increases respectively, in a linear manner. In addition, the fracture aperture also affects the depth of ventilation, which grows as fracture aperture increases. For the maximal examined aperture of 2 cm and wind velocity of 1.25 m/s, fracture ventilation was deeper than 0.45 m. This study sheds new light on fracture ventilation, showing that moderate winds may increase evaporation and gas exchange between fractured media and the atmosphere. Even though wind impact is limited to the top 0.5 m below the ground surface, it is an important process as most of the biological activities, as well as important hydrological processes occur in this region. Wind effect should be considered when modeling mass and energy balances between the Earth upper crust and atmosphere.

  3. Interrupted aortic arch with retrograde subclavian perfusion.

    PubMed

    Kang, Sok-Leng; Forsey, Jonathan; Walsh, Mark A

    2014-06-01

    Type B interrupted aortic arch results in the left subclavian artery being perfused by a patent ductus arteriosus and antegrade flow is usually seen in the left subclavian artery. We describe a case of retrograde perfusion of the left subclavian artery through the circle of Willis in the presence of interrupted aortic arch type B and a restrictive patent ductus arteriosus. This is similar to subclavian steal syndrome when the perfusion pressure from the cerebral circuit is greater than that from the left subclavian artery. Early recognition of this phenomenon may alter management by indicating restriction at ductal level. This case highlights the need for a comprehensive review of both ventricular systolic function and ductal haemodynamics when retrograde flow is seen in the subclavian artery. PMID:25029884

  4. Cardiac tissue engineering using perfusion bioreactor systems

    PubMed Central

    Radisic, Milica; Marsano, Anna; Maidhof, Robert; Wang, Yadong; Vunjak-Novakovic, Gordana

    2009-01-01

    This protocol describes tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cell populations on porous scaffolds (in some cases with an array of channels) and bioreactors with perfusion of culture medium (in some cases supplemented with an oxygen carrier). The overall approach is ‘biomimetic’ in nature as it tends to provide in vivo-like oxygen supply to cultured cells and thereby overcome inherent limitations of diffusional transport in conventional culture systems. In order to mimic the capillary network, cells are cultured on channeled elastomer scaffolds that are perfused with culture medium that can contain oxygen carriers. The overall protocol takes 2–4 weeks, including assembly of the perfusion systems, preparation of scaffolds, cell seeding and cultivation, and on-line and end-point assessment methods. This model is well suited for a wide range of cardiac tissue engineering applications, including the use of human stem cells, and high-fidelity models for biological research. PMID:18388955

  5. The Imbalance of Water in Nature as System

    NASA Astrophysics Data System (ADS)

    Kontar, V. A.; Imbalance of Water in Nature

    2011-12-01

    Consider some of the water-containing area. Choose some the factors which we consider important to the system. The system contains a system factors, and the external environment these factors doesn't contain. Between the system and the external environment must be some flows into the system, out of the system and along the border. If the flows into and out of the system are not equal, that means within the system exactly something is happening. But the equality of the flows into and out of the system does not mean that within the system nothing happens. It is extremely important to determine the time factor. Everything has a beginning and an end. Each factor has its own life from 0 to 1, as well as their watches. Thus that within the system and the environment at the same time are going a lot of the watches and each watch is going by their own pace. System-wide time is needed to describe the system as a whole and to be able to re-measure the individual time of each factor. It is also very important to identify each factor of the system, environment and border. Definition of each particular factor depends on the level of our knowledge. There are many examples where one factor was divided into several, and vice versa, several factors have combined in one or even disappear as a non-existent. Each factor is determined by specific people for reasons of convenience, the specific of tasks, the possible accuracy of measurement, available resources, etc. The development of the science and applications are going to the direction of the clearer separation of factors and the precision of their measurements. Now is extremely important to more clearly define the boundaries of systems, factors and the allowed accuracy of their measurements. With such a revision, many previously balanced situations become to the imbalance. There are many specific details for each case, but they do not change the basic approach described above. If not clearly resolved the questions listed above so will not be obtained any reliable results. For example, the real water arrival occurs in the modes of imbalances such as increasing or decreasing. Water departure also is some set of the several imbalance increase and decrease types. The processes with various orientations interact between each other and reinforce or depress the conjoint effect. This creates some unstable situation, which are not visible by the balanced approach. Therefore some natural disasters actually are coming as unexpected. But in really there are some consequences of the methodological blindness. The Nature is unstable. The imbalance is the main state of the Nature. But mankind does not yet have adequate tools to describing imbalance as it is. In generally now is used more or less successful extrapolation and interpolation of the balance logic. But this is not enough now. So we tried to sharpen here the importance of the works with the imbalance directly.

  6. 30 CFR 75.333 - Ventilation controls.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Ventilation controls. 75.333 Section 75.333 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.333 Ventilation controls. (a) For purposes of this section, “doors” include...

  7. Speech for People with Tracheostomies or Ventilators

    MedlinePLUS

    ... the Public / Speech, Language and Swallowing / Disorders and Diseases Speech for People With Tracheostomies or Ventilators [ en Español ] ... What impact does having a ventilator have on speech? For some people, a ... may need to be connected to a breathing machine (ventilator) that provides a ...

  8. 46 CFR 42.15-45 - Ventilators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Ventilators. 42.15-45 Section 42.15-45 Shipping COAST... Conditions of Assignment of Freeboard § 42.15-45 Ventilators. (a) Ventilators in position 1 or 2 to spaces... extend to more than 7.5 feet above the deck, need not be fitted with closing arrangements...

  9. 46 CFR 42.15-45 - Ventilators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Ventilators. 42.15-45 Section 42.15-45 Shipping COAST... Conditions of Assignment of Freeboard § 42.15-45 Ventilators. (a) Ventilators in position 1 or 2 to spaces... extend to more than 7.5 feet above the deck, need not be fitted with closing arrangements...

  10. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large...

  11. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large...

  12. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large...

  13. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large...

  14. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large...

  15. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation. 168.15-50 Section 168.15-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS CIVILIAN NAUTICAL SCHOOL VESSELS Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately ventilated in a manner suitable...

  16. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation. 168.15-50 Section 168.15-50... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately...the vessel. (b) When mechanical ventilation is provided for sleeping rooms,...

  17. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation. 194.15-5 Section 194.15-5...Scientific Laboratory § 194.15-5 Ventilation. (a) Operations, reactions...equipped with an independent power exhaust ventilation system which terminates so as to...

  18. 46 CFR 72.05-50 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation. 72.05-50 Section 72.05-50...Structural Fire Protection § 72.05-50 Ventilation. (a) Where the term duct is...trunks, plenums, and any other type of ventilation piping, chambers, or...

  19. 9 CFR 91.21 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Ventilation. 91.21 Section 91.21 Animals...Vessels and Accommodations § 91.21 Ventilation. Each underdeck compartment on...equipped with a system of mechanical ventilation that will furnish a complete...

  20. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation. 194.15-5 Section 194.15-5...Scientific Laboratory § 194.15-5 Ventilation. (a) Operations, reactions...equipped with an independent power exhaust ventilation system which terminates so as to...

  1. 46 CFR 72.05-50 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation. 72.05-50 Section 72.05-50...Structural Fire Protection § 72.05-50 Ventilation. (a) Where the term duct is...trunks, plenums, and any other type of ventilation piping, chambers, or...

  2. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation. 168.15-50 Section 168.15-50... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately...the vessel. (b) When mechanical ventilation is provided for sleeping rooms,...

  3. 9 CFR 91.21 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Ventilation. 91.21 Section 91.21 Animals...Vessels and Accommodations § 91.21 Ventilation. Each underdeck compartment on...equipped with a system of mechanical ventilation that will furnish a complete...

  4. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation. 168.15-50 Section 168.15-50... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately...the vessel. (b) When mechanical ventilation is provided for sleeping rooms,...

  5. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation. 194.15-5 Section 194.15-5...Scientific Laboratory § 194.15-5 Ventilation. (a) Operations, reactions...equipped with an independent power exhaust ventilation system which terminates so as to...

  6. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation. 168.15-50 Section 168.15-50... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately...the vessel. (b) When mechanical ventilation is provided for sleeping rooms,...

  7. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation. 194.15-5 Section 194.15-5...Scientific Laboratory § 194.15-5 Ventilation. (a) Operations, reactions...equipped with an independent power exhaust ventilation system which terminates so as to...

  8. 9 CFR 91.21 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Ventilation. 91.21 Section 91.21 Animals...Vessels and Accommodations § 91.21 Ventilation. Each underdeck compartment on...equipped with a system of mechanical ventilation that will furnish a complete...

  9. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation. 194.15-5 Section 194.15-5...Scientific Laboratory § 194.15-5 Ventilation. (a) Operations, reactions...equipped with an independent power exhaust ventilation system which terminates so as to...

  10. 9 CFR 91.21 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Ventilation. 91.21 Section 91.21 Animals...Vessels and Accommodations § 91.21 Ventilation. Each underdeck compartment on...equipped with a system of mechanical ventilation that will furnish a complete...

  11. 14 CFR 23.831 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Ventilation. 23.831 Section 23.831 Aeronautics...Cargo Accommodations § 23.831 Ventilation. Link to an amendment published...set forth as follows: § 23.831 Ventilation. (c) For jet pressurized...

  12. 46 CFR 72.05-50 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation. 72.05-50 Section 72.05-50...Structural Fire Protection § 72.05-50 Ventilation. (a) Where the term duct is...trunks, plenums, and any other type of ventilation piping, chambers, or...

  13. May 1999 LBNL -42975 ASHRAE'S RESIDENTIAL VENTILATION

    E-print Network

    May 1999 LBNL - 42975 ASHRAE'S RESIDENTIAL VENTILATION STANDARD: EXEGESIS OF PROPOSED STANDARD 62 Committee on "Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings", SPC 62.2P, approved ASHRAE's first complete standard on residential ventilation for public review

  14. 46 CFR 72.05-50 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation. 72.05-50 Section 72.05-50...Structural Fire Protection § 72.05-50 Ventilation. (a) Where the term duct is...trunks, plenums, and any other type of ventilation piping, chambers, or...

  15. 46 CFR 72.05-50 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation. 72.05-50 Section 72.05-50...Structural Fire Protection § 72.05-50 Ventilation. (a) Where the term duct is...trunks, plenums, and any other type of ventilation piping, chambers, or...

  16. 9 CFR 91.21 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Ventilation. 91.21 Section 91.21 Animals...Vessels and Accommodations § 91.21 Ventilation. Each underdeck compartment on...equipped with a system of mechanical ventilation that will furnish a complete...

  17. Bilateral arm power imbalance in swim bench exercise to exhaustion.

    PubMed

    Potts, A D; Charlton, J E; Smith, H M

    2002-12-01

    We examined the supposition that swimmers may exhibit an imbalance in bilateral arm power output during simulated swimming exercise. Ten competitive front crawl swimmers (5 males, 5 females; age 20.5+/-2.3 years; height 1.74+/-0.09 m; body mass 72.0+/-16.7 kg; 400 m freestyle swim time 278+/-20.5 s; mean +/- s) performed four incremental (10 W x min(-1)) swim ramp tests on a computer-interfaced biokinetic swim bench ergometer. External power output from each arm was measured continuously to exhaustion. The results showed that, throughout the course of the simulated swim, external power output clearly favoured the left arm (F1,9 = 12.5, P= 0.006). This was especially evident in the final 30 s to exhaustion, when 54.0+/-3.87% of external power output was derived from the left arm versus 46.0+/-3.87% from the right arm. The disparity in external power output was further highlighted when the participants were grouped into unilateral and bilateral breathers. Unilateral breathers (n = 5) produced 57.1+/-2.62% of external power output from the left armversus 42.9+/-2.62% from the right arm (P= 0.001). Bilateral breathers (n = 5) exhibited a more balanced external power output of 51.0+/-1.82% from the left arm and 49.0+/-1.82% from the right arm (P = 0.177). Evidence of power imbalance in the simulated swimming stroke may have important implications for optimizing swim performance. The observed power imbalance may be reduced when a bilateral breathing technique is adopted. PMID:12477007

  18. Mass imbalance error of waterhammer equations and leak detection

    SciTech Connect

    Liou, C.P. . Dept. of Civil Engineering)

    1994-03-01

    The waterhammer equations can be used to compute mass inventory changes for pipeline leak detection. In such applications the pipeline is monitored continuously in time and there is no clear demarcation between steady-state and transients. This paper addresses a mass imbalance error of the waterhammer equations. The authors establish that the net mass influx error for the waterhammer equations at the steady-state with maximum flow-rate bounds the same error during transients. A method to evaluate this bound is presented. Using petroleum products pipelines as an example, they show that the waterhammer equations are not accurate enough for leak detection in some systems.

  19. Western Interconnection Energy Imbalance Market Status and Prospects (Presentation)

    SciTech Connect

    Milligan, M.; Kirby, B.; King, J.; Beuning, S.

    2011-10-01

    This presentation describes how a new wholesale electricity market for energy imbalance ancillary services could be implemented and operated. Some conclusions of this presentation are: (1) Method for calculating additional reserve requirements due to wind and solar production; (2) EIM results in substantial reduction in reserves requirements and ramping demand; (3) Reduced participation reduces benefits for all but reduces the benefits to non-participants the most; (4) Full participation leads to maximum benefit across the Western Interconnection, up to 42% of total reserve requirement; and (5) Regional EIM implementations have smaller but substantial benefits.

  20. Hypoxic treatment of human dual placental perfusion induces a preeclampsia-like inflammatory response.

    PubMed

    Jain, Arjun; Schneider, Henning; Aliyev, Eldar; Soydemir, Fatimah; Baumann, Marc; Surbek, Daniel; Hediger, Matthias; Brownbill, Paul; Albrecht, Christiane

    2014-08-01

    Preeclampsia is a human pregnancy-specific disorder characterized by a placental pro-inflammatory response in combination with an imbalance of angiogenic factors and clinical symptoms, including hypertension and proteinuria. Insufficient uteroplacental oxygenation in preeclampsia due to impaired trophoblast invasion during placentation is believed to be responsible for many of the molecular events leading to the clinical manifestations of this disease. We investigated the use of hypoxic treatment of the dual placental perfusion system as a model for preeclampsia. A modified perfusion technique allowed us to achieve a mean soluble oxygen tension within the intervillous space (IVS) of 5-7% for normoxia and <3% for hypoxia (as a model for preeclampsia). We assayed for the levels of different inflammatory cytokines, oxidative stress markers, as well as other factors, such as endothelin (ET)-1 that are known to be implicated as part of the inflammatory response in preeclampsia. Our results show a significant increase under hypoxia in the levels of different inflammatory cytokines, including IL-6 (P=0.002), IL-8 (P<0.0001), TNF-? (P=0.032) and IFN-? (P=0.009) at 360?min in maternal venous samples (n=6). There was also a significant increase in ET-1 levels under hypoxia both on the maternal side at 30?min (P=0.003) and fetal side at 360?min (P=0.036) (n=6). Other markers of oxidative stress, including malondialdehyde and 8-iso-protaglandin F2? (P=0.009) also show increased levels. Overall, these findings indicate that exposure of ex vivo dually perfused placental tissue to hypoxia provides a useful model for mimicking the inflammatory response characteristic of preeclampsia. This would therefore provide a powerful tool for studying and further delineating the molecular mechanisms involved in the underlying pathophysiology of preeclampsia. PMID:24933425

  1. Effects of laser acupuncture on blood perfusion rate

    NASA Astrophysics Data System (ADS)

    Wang, Xian-ju; Zeng, Chang-chun; Liu, Han-ping; Liu, Song-hao; Liu, Liang-gang

    2006-09-01

    Based on Pennes equation, the influences of the intensity and the impulse frequency of laser acupuncture on the point tissues' blood flow perfusion rate are discussed. We find that the blood perfusion rate of point tissue increases with the intensity of laser acupuncture increasing. After impulse laser acupuncture the point tissue blood perfusion rate increase little, but after continuum laser acupuncture the point tissues blood perfusion rate increase much.

  2. Stress-first Myocardial Perfusion Imaging.

    PubMed

    Hussain, Nasir; Parker, Matthew W; Henzlova, Milena J; Duvall, William Lane

    2016-02-01

    Stress-first approaches to myocardial perfusion imaging provide diagnostically and prognostically accurate perfusion data equivalent to a full rest-stress study, save time in the imaging laboratory, and reduce the radiation exposure to patients and laboratory staff. Converting a nuclear cardiology laboratory from a conventional rest-stress strategy to a stress-first approach involves challenges such as the need for attenuation correction, triage of patients to an appropriate protocol, real-time review of stress images, and consideration of differential reimbursement. PMID:26590780

  3. Preventing Ventilation On Sailboard Skegs

    NASA Technical Reports Server (NTRS)

    Caldwell, Richard A.

    1990-01-01

    Design effort undertaken to solve spinout problem plaguing high-performance sailboards. Proposed skeg section designed by use of computer model of pressure field and boundary layer. Prevents ventilation by maintaining attached boundary-layer flow throughout operating environment. Cavitation also avoided by preventing valleys in pressure distribution while skeg operated throughout its range.

  4. Review of Residential Ventilation Technologies

    SciTech Connect

    Russell, Marion L.; Sherman, Max H.; Rudd, Armin

    2005-03-01

    This paper reviews current and potential ventilation technologies for residential buildings in North America and a few in Europe. The major technologies reviewed include a variety of mechanical systems, natural ventilation, and passive ventilation. Key parameters that are related to each system include operating costs, installation costs, ventilation rates, heat recovery potential. It also examines related issues such as infiltration, duct systems, filtration options, noise, and construction issues. This report describes a wide variety of systems currently on the market that can be used to meet ASHRAE standard 62.2. While these systems generally fall into the categories of supply, exhaust or balanced, the specifics of each system are driven by concerns that extend beyond those in the standard and are discussed. Some of these systems go beyond the current standard by providing additional features (such as air distribution or pressurization control). The market will decide the immediate value of such features, but ASHRAE may wish to consider modifications to the standard in the future.

  5. The basis and basics of mechanical ventilation.

    PubMed

    Bone, R C; Eubanks, D H

    1991-06-01

    The development of mechanical ventilators and the procedures for their application began with the simple foot pump developed by Fell O'Dwyer in 1888. Ventilators have progressed through three generations, beginning with intermittent positive pressure breathing units such as the Bird and Bennett device in the 1960s. These were followed by second-generation units--represented by the Bennett MA-2 ventilator--in the 1970s, and the third-generation microprocessor-controlled units of today. During this evolutionary process clinicians recognized Types I and II respiratory failure as being indicators for mechanical ventilatory support. More recently investigators have expanded, clarified, and clinically applied the physiology of the work of breathing (described by Julius Comroe and other pioneers) to muscle fatigue, requiring ventilatory support. A ventilator classification system can help the clinician understand how ventilators function and under what conditions they may fail to operate as desired. Pressure-support ventilation is an example of how industry has responded to a clinical need--that is, to unload the work of breathing. All positive pressure ventilators generate tidal volumes by using power sources such as medical gas cylinders, air compressors, electrically driven turbines, or piston driven motors. Positive end-expiratory pressures, synchronized intermittent mandatory ventilation, pressure support ventilation, pressure release ventilation, and mandatory minute ventilation, are examples of the special functions available on modern ventilators. Modern third-generation ventilators use microprocessors to control operational functions and monitors. Because these units have incorporated the experience learned from earlier ventilators, it is imperative that clinicians understand basic ventilator operation and application in order to most effectively prescribe and assess their use. PMID:2036934

  6. Assessment of regional lung ventilation by electrical impedance tomography in a patient with unilateral bronchial stenosis and a history of tuberculosis.

    PubMed

    Marinho, Liégina Silveira; Sousa, Nathalia Parente de; Barros, Carlos Augusto Barbosa da Silveira; Matias, Marcelo Silveira; Monteiro, Luana Torres; Beraldo, Marcelo do Amaral; Costa, Eduardo Leite Vieira; Amato, Marcelo Britto Passos; Holanda, Marcelo Alcantara

    2013-01-01

    Bronchial stenosis can impair regional lung ventilation by causing abnormal, asymmetric airflow limitation. Electrical impedance tomography (EIT) is an imaging technique that allows the assessment of regional lung ventilation and therefore complements the functional assessment of the lungs. We report the case of a patient with left unilateral bronchial stenosis and a history of tuberculosis, in whom regional lung ventilation was assessed by EIT. The EIT results were compared with those obtained by ventilation/perfusion radionuclide imaging. The patient was using nasal continuous positive airway pressure (CPAP) for the treatment of obstructive sleep apnea syndrome. Therefore, we studied the effects of postural changes and of the use of nasal CPAP. The EIT revealed heterogeneous distribution of regional lung ventilation, the ventilation being higher in the right lung, and this distribution was influenced by postural changes and CPAP use. The EIT assessment of regional lung ventilation produced results similar to those obtained with the radionuclide imaging technique and had the advantage of providing a dynamic evaluation without radiation exposure. PMID:24473768

  7. High-volume hemofiltration and prone ventilation in subarachnoid hemorrhage complicated by severe acute respiratory distress syndrome and refractory septic shock

    PubMed Central

    Cornejo, Rodrigo; Romero, Carlos; Ugalde, Diego; Bustos, Patricio; Diaz, Gonzalo; Galvez, Ricardo; Llanos, Osvaldo; Tobar, Eduardo

    2014-01-01

    We report the successful treatment of two patients with aneurismal subarachnoid hemorrhage complicated by severe respiratory failure and refractory septic shock using simultaneous prone position ventilation and high-volume hemofiltration. These rescue therapies allowed the patients to overcome the critical situation without associated complications and with no detrimental effects on the intracranial and cerebral perfusion pressures. Prone position ventilation is now an accepted therapy for severe acute respiratory distress syndrome, and high-volume hemofiltration is a non-conventional hemodynamic support that has several potential mechanisms for improving septic shock. In this manuscript, we briefly review these therapies and the related evidence. When other conventional treatments are insufficient for providing safe limits of oxygenation and perfusion as part of basic neuroprotective care in subarachnoid hemorrhage patients, these rescue therapies should be considered on a case-by-case basis by an experienced critical care team. PMID:25028955

  8. Numerical study of variable lung ventilation strategies

    E-print Network

    Yadav, Reena; Hiremath, Kirankumar; Bagler, Ganesh

    2015-01-01

    Mechanical ventilation is used for patients with a variety of lung diseases. Traditionally, ventilators have been designed to monotonously deliver equal sized breaths. While it may seem intuitive that lungs may benefit from unvarying and stable ventilation pressure strategy, recently it has been reported that variable lung ventilation is advantageous. In this study, we analyze the mean tidal volume in response to different `variable ventilation pressure' strategies. We found that uniformly distributed variability in pressure gives the best tidal volume as compared to that of normal, scale- free, log normal and linear distributions.

  9. Hypobaric Hypoxia Imbalances Mitochondrial Dynamics in Rat Brain Hippocampus.

    PubMed

    Jain, Khushbu; Prasad, Dipti; Singh, Shashi Bala; Kohli, Ekta

    2015-01-01

    Brain is predominantly susceptible to oxidative stress and mitochondrial dysfunction during hypobaric hypoxia, and therefore undergoes neurodegeneration due to energy crisis. Evidences illustrate a high degree of association for mitochondrial fusion/fission imbalance and mitochondrial dysfunction. Mitochondrial fusion/fission is a recently reported dynamic mechanism which frequently occurs among cellular mitochondrial network. Hence, the study investigated the temporal alteration and involvement of abnormal mitochondrial dynamics (fusion/fission) along with disturbed mitochondrial functionality during chronic exposure to hypobaric hypoxia (HH). The Sprague-Dawley rats were exposed to simulated high altitude equivalent to 25000?ft for 3, 7, 14, 21, and 28 days. Mitochondrial morphology, distribution within neurons, enzyme activity of respiratory complexes, ?? m , ADP: ATP, and expression of fission/fusion key proteins were determined. Results demonstrated HH induced alteration in mitochondrial morphology by damaged, small mitochondria observed in neurons with disturbance of mitochondrial functionality and reduced mitochondrial density in neuronal processes manifested by excessive mitochondrial fragmentation (fission) and decreased mitochondrial fusion as compared to unexposed rat brain hippocampus. The study suggested that imbalance in mitochondrial dynamics is one of the noteworthy mechanisms occurring in hippocampal neurons during HH insult. PMID:26236504

  10. Quantification of the effect of energy imbalance on bodyweight

    PubMed Central

    Hall, Kevin D; Sacks, Gary; Chandramohan, Dhruva; Chow, Carson C; Wang, Y Claire; Gortmaker, Steven L; Swinburn, Boyd A

    2013-01-01

    Obesity interventions can result in weight loss, but accurate prediction of the bodyweight time course requires properly accounting for dynamic energy imbalances. In this report, we describe a mathematical modelling approach to adult human metabolism that simulates energy expenditure adaptations during weight loss. We also present a web-based simulator for prediction of weight change dynamics. We show that the bodyweight response to a change of energy intake is slow, with half times of about 1 year. Furthermore, adults with greater adiposity have a larger expected weight loss for the same change of energy intake, and to reach their steady-state weight will take longer than it would for those with less initial body fat. Using a population-averaged model, we calculated the energy-balance dynamics corresponding to the development of the US adult obesity epidemic. A small persistent average daily energy imbalance gap between intake and expenditure of about 30 kJ per day underlies the observed average weight gain. However, energy intake must have risen to keep pace with increased expenditure associated with increased weight. The average increase of energy intake needed to sustain the increased weight (the maintenance energy gap) has amounted to about 0·9 MJ per day and quantifies the public health challenge to reverse the obesity epidemic. PMID:21872751

  11. Hypobaric Hypoxia Imbalances Mitochondrial Dynamics in Rat Brain Hippocampus

    PubMed Central

    Jain, Khushbu; Prasad, Dipti; Singh, Shashi Bala; Kohli, Ekta

    2015-01-01

    Brain is predominantly susceptible to oxidative stress and mitochondrial dysfunction during hypobaric hypoxia, and therefore undergoes neurodegeneration due to energy crisis. Evidences illustrate a high degree of association for mitochondrial fusion/fission imbalance and mitochondrial dysfunction. Mitochondrial fusion/fission is a recently reported dynamic mechanism which frequently occurs among cellular mitochondrial network. Hence, the study investigated the temporal alteration and involvement of abnormal mitochondrial dynamics (fusion/fission) along with disturbed mitochondrial functionality during chronic exposure to hypobaric hypoxia (HH). The Sprague-Dawley rats were exposed to simulated high altitude equivalent to 25000?ft for 3, 7, 14, 21, and 28 days. Mitochondrial morphology, distribution within neurons, enzyme activity of respiratory complexes, ??m, ADP: ATP, and expression of fission/fusion key proteins were determined. Results demonstrated HH induced alteration in mitochondrial morphology by damaged, small mitochondria observed in neurons with disturbance of mitochondrial functionality and reduced mitochondrial density in neuronal processes manifested by excessive mitochondrial fragmentation (fission) and decreased mitochondrial fusion as compared to unexposed rat brain hippocampus. The study suggested that imbalance in mitochondrial dynamics is one of the noteworthy mechanisms occurring in hippocampal neurons during HH insult. PMID:26236504

  12. Effects of imbalance and geometric error on precision grinding machines

    SciTech Connect

    Bibler, J.E.

    1997-06-01

    To study balancing in grinding, a simple mechanical system was examined. It was essential to study such a well-defined system, as opposed to a large, complex system such as a machining center. The use of a compact, well-defined system enabled easy quantification of the imbalance force input, its phase angle to any geometric decentering, and good understanding of the machine mode shapes. It is important to understand a simple system such as the one I examined given that imbalance is so intimately coupled to machine dynamics. It is possible to extend the results presented here to industrial machines, although that is not part of this work. In addition to the empirical testing, a simple mechanical system to look at how mode shapes, balance, and geometric error interplay to yield spindle error motion was modelled. The results of this model will be presented along with the results from a more global grinding model. The global model, presented at ASPE in November 1996, allows one to examine the effects of changing global machine parameters like stiffness and damping. This geometrically abstract, one-dimensional model will be presented to demonstrate the usefulness of an abstract approach for first-order understanding but it will not be the main focus of this thesis. 19 refs., 36 figs., 10 tables.

  13. Night ventilation control strategies in office buildings

    SciTech Connect

    Wang, Zhaojun; Yi, Lingli; Gao, Fusheng

    2009-10-15

    In moderate climates night ventilation is an effective and energy-efficient approach to improve the indoor thermal environment for office buildings during the summer months, especially for heavyweight construction. However, is night ventilation a suitable strategy for office buildings with lightweight construction located in cold climates? In order to answer this question, the whole energy-consumption analysis software EnergyPlus was used to simulate the indoor thermal environment and energy consumption in typical office buildings with night mechanical ventilation in three cities in northern China. The summer outdoor climate data was analyzed, and three typical design days were chosen. The most important factors influencing night ventilation performance such as ventilation rates, ventilation duration, building mass and climatic conditions were evaluated. When night ventilation operation time is closer to active cooling time, the efficiency of night ventilation is higher. With night ventilation rate of 10 ach, the mean radiant temperature of the indoor surface decreased by up to 3.9 C. The longer the duration of operation, the more efficient the night ventilation strategy becomes. The control strategies for three locations are given in the paper. Based on the optimized strategies, the operation consumption and fees are calculated. The results show that more energy is saved in office buildings cooled by a night ventilation system in northern China than ones that do not employ this strategy. (author)

  14. Liquid ventilation: it's not science fiction anymore.

    PubMed

    Norris, M K; Fuhrman, B P; Leach, C L

    1994-08-01

    Liquid ventilation is, by all initial considerations, an unconventional concept. Decades of research, however, have found that by using perfluorocarbons, which are capable of holding high concentrations of critical gases such as oxygen and carbon dioxide, gas exchange optimal enough to support life is possible with no known toxic effects. The earliest method of liquid ventilation, tidal liquid breathing, involved infusion and active removal of tidal volumes of perfluorocarbons by a liquid ventilator for gas exchange. Recently, a new method of partial liquid breathing, called perfluorocarbon-associated gas exchange, makes the process of liquid ventilation simpler by using conventional gas ventilators. Current research is showing great promise in the use of liquid ventilation for patients with pulmonary pathology. Critical care nurses should become knowledgeable of this new mode of ventilation and be prepared to meet the special needs of this unique population. PMID:7780839

  15. Perfusion Quantification Using Gaussian Process Deconvolution

    E-print Network

    Edinburgh, University of

    Perfusion Quantification Using Gaussian Process Deconvolution I.K. Andersen,1,2* A. Szymkowiak,1 C using dynamic susceptibility contrast MRI (DSC-MRI) requires deconvolution to obtain the residual impulse response function (IRF). In this work, a method using the Gaussian process for deconvolution (GPD

  16. Summary of human responses to ventilation

    SciTech Connect

    Seppanen, Olli A.; Fisk, William J.

    2004-06-01

    The effects of ventilation on indoor air quality and health is a complex issue. It is known that ventilation is necessary to remove indoor generated pollutants from indoor air or dilute their concentration to acceptable levels. But, as the limit values of all pollutants are not known, the exact determination of required ventilation rates based on pollutant concentrations and associated risks is seldom possible. The selection of ventilation rates has to be based also on epidemiological research (e.g. Seppanen et al., 1999), laboratory and field experiments (e.g. CEN 1996, Wargocki et al., 2002a) and experience (e.g. ECA 2003). Ventilation may also have harmful effects on indoor air quality and climate if not properly designed, installed, maintained and operated as summarized by Seppdnen (2003). Ventilation may bring indoors harmful substances that deteriorate the indoor environment. Ventilation also affects air and moisture flow through the building envelope and may lead to moisture problems that deteriorate the structures of the building. Ventilation changes the pressure differences over the structures of building and may cause or prevent the infiltration of pollutants from structures or adjacent spaces. Ventilation is also in many cases used to control the thermal environment or humidity in buildings. Ventilation can be implemented with various methods which may also affect health (e.g. Seppdnen and Fisk, 2002, Wargocki et al., 2002a). In non residential buildings and hot climates, ventilation is often integrated with air-conditioning which makes the operation of ventilation system more complex. As ventilation is used for many purposes its health effects are also various and complex. This paper summarizes the current knowledge on positive and negative effects of ventilation on health and other human responses. The focus of the paper is on office-type working environment and residential buildings. In the industrial premises the problems of air quality are usually more complex and case specific. They are subject to occupational safety legislation and not discussed here.

  17. The Perfusion Downunder Collaborative Database Project

    PubMed Central

    Newland, Richard; Baker, Robert A.; Stanley, Rebecca; Place, Katherine; Willcox, Timothy W.

    2008-01-01

    Abstract: The Perfusion Downunder Collaboration provides research infrastructure and support to the Australian and New Zealand perfusion community, with the objective of determining best practices and producing relevant research publications. The Perfusion Downunder Collaborative Database (PDUCD) has been created for the purpose of collecting a dataset for cardiopulmonary bypass (CPB) procedures that includes integration with commercially available CPB data collection software. Initial testing of the PDUCD involved collection of data from four Australian and New Zealand hospitals from March to July 2007. Data from 513 procedures were compared with the concurrent Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) database report to assess the validity of the collected data. Demographic, preoperative, and procedural variables were comparable between databases. Perfusion variables showed a median nasopharyngeal temperature of 36.7°C at separation from CPB (range, 35.3–37.5°C), which was similar to maximum nasopharyngeal temperature (median, 36.8°C). Median arterial flow and mean arterial pressure were 4.2 L/min and 57.2 mmHg, respectively. Control charts indicate a central tendency of 12.5 minutes for mean arterial pressure <50 mmHg and 3.5 minutes for arterial flow <1.6 L/min/m2 (cumulative time). There was no difference in median minimum and maximum blood glucose between diabetic and nondiabetic patients during CPB with 40% of patients receiving insulin. Median minimum and maximum activated clotting time (ACT) during CPB was 581 and 692 seconds, respectively. Outcome data for isolated coronary artery bypass grafting were similar for mortality (only) (both 1.8%). Initial data collection showed concurrent validity compared with the ASCTS database. The inclusion of a large quantity of calculated CPB variables in the dataset highlights the benefits of electronic data collection as a research tool within a collaborative research network and the potential for the evaluation of the relationships between patient risk factors, perfusion practice, and patient outcomes. PMID:18853827

  18. Effects of chiral imbalance and magnetic field on pion superfluidity and color superconductivity

    NASA Astrophysics Data System (ADS)

    Cao, Gaoqing; Zhuang, Pengfei

    2015-11-01

    The effects of chiral imbalance and external magnetic field on pion superfluidity and color superconductivity are investigated in extended Nambu-Jona-Lasinio models. We take the Schwinger approach to treat the interaction between the charged pion condensate and magnetic field at finite isospin density and include simultaneously the chiral imbalance and magnetic field at finite baryon density. For the superfluidity, the chiral imbalance and magnetic field lead to catalysis and inverse catalysis effects, respectively. For the superconductivity, the chiral imbalance enhances the critical baryon density, and the magnetic field results in a de Haas-van Alphan oscillation on the phase transition line.

  19. Regional comparison of technetium-99m DTPA aerosol and radioactive gas ventilation (xenon and krypton) studies in patients with suspected pulmonary embolism.

    PubMed

    Ramanna, L; Alderson, P O; Waxman, A D; Berman, D S; Brachman, M B; Kroop, S A; Goldsmith, M; Tanasescu, D E

    1986-09-01

    The regional distribution of [99mTc]DTPA aerosol was compared with that of 133Xe (n = 30) and krypton (n = 24) in a group of patients with suspected pulmonary embolism. All patients had an aerosol study using a recently available commercial generator system, a ventilation study with one of the gases, and perfusion imaging. Regional information was assessed visually on xenon, krypton, and aerosol studies independently by considering each lung as three equal-sized zones. In addition, gas ventilation findings peripheral to regions of aerosol turbulence ("hot spots") were evaluated. Only 64% of the zones were in complete agreement on xenon and aerosol. Most of the discordance between xenon and aerosol was accounted for by minor degrees of 133Xe washout retention in zones that appeared normal in the aerosol study. An agreement rate of 85% was noted between 81mKr and aerosol regionally. The regions of discordance between aerosol and gas studies, however, usually were associated with unimpressive perfusion defects that did not change the scintigraphic probability for pulmonary embolism in any patient. Regarding zones of aerosol hyperdeposition, 76% had associated washout abnormalities on xenon; however, there was no correlation between the presence of these abnormalities or perfusion abnormalities. The results confirm the high sensitivity of 133Xe washout imaging, but suggest that radioaerosol imaging will detect most parenchymal abnormalities associated with perfusion defects of significance. PMID:3528412

  20. Basic Surgical Techniques in the Göttingen Minipig: Intubation, Bladder Catheterization, Femoral Vessel Catheterization, and Transcardial Perfusion

    PubMed Central

    Ettrup, Kaare S.; Glud, Andreas N.; Orlowski, Dariusz; Fitting, Lise M.; Meier, Kaare; Soerensen, Jens Christian; Bjarkam, Carsten R.; Alstrup, Aage K. Olsen

    2011-01-01

    The emergence of the Göttingen minipig in research of topics such as neuroscience, toxicology, diabetes, obesity, and experimental surgery reflects the close resemblance of these animals to human anatomy and physiology 1-6.The size of the Göttingen minipig permits the use of surgical equipment and advanced imaging modalities similar to those used in humans 6-8. The aim of this instructional video is to increase the awareness on the value of minipigs in biomedical research, by demonstrating how to perform tracheal intubation, transurethral bladder catheterization, femoral artery and vein catheterization, as well as transcardial perfusion. Endotracheal Intubation should be performed whenever a minipig undergoes general anesthesia, because it maintains a patent airway, permits assisted ventilation and protects the airways from aspirates. Transurethral bladder catheterization can provide useful information about about hydration state as well as renal and cardiovascular function during long surgical procedures. Furthermore, urinary catheterization can prevent contamination of delicate medico-technical equipment and painful bladder extension which may harm the animal and unnecessarily influence the experiment due to increased vagal tone and altered physiological parameters. Arterial and venous catheterization is useful for obtaining repeated blood samples and monitoring various physiological parameters. Catheterization of femoral vessels is preferable to catheterization of the neck vessels for ease of access, when performing experiments involving frame-based stereotaxic neurosurgery and brain imaging. When performing vessel catheterization in survival studies, strict aseptic technique must be employed to avoid infections6. Transcardial perfusion is the most effective fixation method, and yields preeminent results when preparing minipig organs for histology and histochemistry2,9. For more information about anesthesia, surgery and experimental techniques in swine in general we refer to Swindle 2007. Supplementary information about premedication and induction of anesthesia, assisted ventilation, analgesia, pre- and postoperative care of Göttingen minipigs are available via the internet at http://www.minipigs.com10. For extensive information about porcine anatomy we refer to Nickel et al. Vol. 1-511. PMID:21730947

  1. Development of a Residential Integrated Ventilation Controller

    SciTech Connect

    Staff Scientist; Walker, Iain; Sherman, Max; Dickerhoff, Darryl

    2011-12-01

    The goal of this study was to develop a Residential Integrated Ventilation Controller (RIVEC) to reduce the energy impact of required mechanical ventilation by 20percent, maintain or improve indoor air quality and provide demand response benefits. This represents potential energy savings of about 140 GWh of electricity and 83 million therms of natural gas as well as proportional peak savings in California. The RIVEC controller is intended to meet the 2008 Title 24 requirements for residential ventilation as well as taking into account the issues of outdoor conditions, other ventilation devices (including economizers), peak demand concerns and occupant preferences. The controller is designed to manage all the residential ventilation systems that are currently available. A key innovation in this controller is the ability to implement the concept of efficacy and intermittent ventilation which allows time shifting of ventilation. Using this approach ventilation can be shifted away from times of high cost or high outdoor pollution towards times when it is cheaper and more effective. Simulations, based on the ones used to develop the new residential ventilation requirements for the California Buildings Energy code, were used to further define the specific criteria and strategies needed for the controller. These simulations provide estimates of the energy, peak power and contaminant improvement possible for different California climates for the various ventilation systems. Results from a field test of the prototype controller corroborate the predicted performance.

  2. Changes in global net radiative imbalance 1985–2012

    PubMed Central

    Allan, Richard P; Liu, Chunlei; Loeb, Norman G; Palmer, Matthew D; Roberts, Malcolm; Smith, Doug; Vidale, Pier-Luigi

    2014-01-01

    Combining satellite data, atmospheric reanalyses, and climate model simulations, variability in the net downward radiative flux imbalance at the top of Earth's atmosphere (N) is reconstructed and linked to recent climate change. Over the 1985–1999 period mean N (0.34 ± 0.67?Wm?2) is lower than for the 2000–2012 period (0.62 ± 0.43?Wm?2, uncertainties at 90% confidence level) despite the slower rate of surface temperature rise since 2000. While the precise magnitude of N remains uncertain, the reconstruction captures interannual variability which is dominated by the eruption of Mount Pinatubo in 1991 and the El Niño Southern Oscillation. Monthly deseasonalized interannual variability in N generated by an ensemble of nine climate model simulations using prescribed sea surface temperature and radiative forcings and from the satellite-based reconstruction is significantly correlated (r?0.6) over the 1985–2012 period. PMID:25821270

  3. Colombian late cretaceous tropical planktonic foraminifera: Redressing the imbalance

    SciTech Connect

    McCarthy, L.D.

    1993-02-01

    Recent work involving Late Cretaceous planktonic foraminifera has concentrated on European and other areas in the Northern Hemisphere. Many of the biostratigraphical and evolutionary models reflect this geographical restriction and ignore earlier studies from tropical areas. In 1955 Rolando Gandolfi described many new species and subspecies from Colombia and provided a different view of the evolutionary development of planktonic foraminifera. A re-examination of the Gandolfi type collection using Scanning Electron Micrography (Environmental Chamber technique) integrated with Colombian well samples from onshore Guajira area, Middle and Upper Magdalena Valley and Putumayo Basin has given a new view into the evolutionary development of Late Cretaceous planktonic foraminifera. This has enabled a modified globigerine Late Cretaceous biostratigraphy to be constructed for Colombia. This work redresses the imbalance between studies of tropical and northern high latitude Late Cretaceous planktonic foraminifera and provides an insight into the paleoenvironmental and paleoclimatological factors influencing the Colombian region at the time.

  4. Depersonalization disorder may be related to glutamate receptor activation imbalance.

    PubMed

    Pikwer, Andreas

    2011-10-01

    Low-dose ketamine administration mimics, both clinically and on gross neuroimaging, depersonalization disorder. The perceptual effects of ketamine may be due to secondary stimulation of glutamate release and lamotrigine, possibly by inhibited glutamate release, may reduce some of ketamine's so-called dissociative effects. However, lamotrigine does not seem to be useful in the treatment of depersonalization disorder. Glutamate release in prefrontal cortex is increased by subanaesthetic doses of ketamine, resulting in increased inhibition, possibly via intercalated GABAerg cells, of projections from amygdala, affecting structures critically involved in depersonalization. I speculate that, in depersonalization disorder, the increased glutamate activity in prefrontal cortex is due to intrinsic imbalance, resulting in long-term potentiation, at the postsynaptic glutamate receptors on the GABAerg interneurons while the same receptor abnormality at the synapses on the intercalated GABAerg cells of the amygdala result in long-term depression in the case of either normal or high glutamate release. PMID:21742442

  5. Microbial imbalance and intestinal pathologies: connections and contributions

    PubMed Central

    Yang, Ye; Jobin, Christian

    2014-01-01

    Microbiome analysis has identified a state of microbial imbalance (dysbiosis) in patients with chronic intestinal inflammation and colorectal cancer. The bacterial phylum Proteobacteria is often overrepresented in these individuals, with Escherichia coli being the most prevalent species. It is clear that a complex interplay between the host, bacteria and bacterial genes is implicated in the development of these intestinal diseases. Understanding the basic elements of these interactions could have important implications for disease detection and management. Recent studies have revealed that E. coli utilizes a complex arsenal of virulence factors to colonize and persist in the intestine. Some of these virulence factors, such as the genotoxin colibactin, were found to promote colorectal cancer in experimental models. In this Review, we summarize key features of the dysbiotic states associated with chronic intestinal inflammation and colorectal cancer, and discuss how the dysregulated interplay between host and bacteria could favor the emergence of E. coli with pathological traits implicated in these pathologies. PMID:25256712

  6. Optimal weight based on energy imbalance and utility maximization

    NASA Astrophysics Data System (ADS)

    Sun, Ruoyan

    2016-01-01

    This paper investigates the optimal weight for both male and female using energy imbalance and utility maximization. Based on the difference of energy intake and expenditure, we develop a state equation that reveals the weight gain from this energy gap. We ?construct an objective function considering food consumption, eating habits and survival rate to measure utility. Through applying mathematical tools from optimal control methods and qualitative theory of differential equations, we obtain some results. For both male and female, the optimal weight is larger than the physiologically optimal weight calculated by the Body Mass Index (BMI). We also study the corresponding trajectories to steady state weight respectively. Depending on the value of a few parameters, the steady state can either be a saddle point with a monotonic trajectory or a focus with dampened oscillations.

  7. Spin-Imbalance in a One-Dimensional Fermi Gas

    E-print Network

    Liao, Yean-an; Paprotta, Tobias; Li, Wenhui; Partridge, Guthrie B; Hulet, Randall G; Baur, Stefan K; Mueller, Erich J

    2009-01-01

    Superconductivity and magnetism generally do not coexist. Changing the relative number of up and down spin electrons disrupts the basic mechanism of superconductivity, where atoms of opposite momentum and spin form Cooper pairs. Nearly forty years ago Fulde and Ferrell and Larkin and Ovchinnikov proposed an exotic pairing mechanism (FFLO) where magnetism is accommodated by formation of pairs with finite momentum. Despite intense theoretical and experimental efforts, however, polarized superconductivity remains largely elusive. Here we report experimental measurements of density profiles of a two spin mixture of ultracold 6Li atoms trapped in an array of one dimensional (1D) tubes, a system analogous to electrons in 1D wires. At finite spin imbalance, the system phase separates with an inverted phase profile in comparison to the three-dimensional case. In 1D we find a partially polarized core surrounded by wings composed of either a completely paired BCS superfluid or a fully polarized Fermi gas, depending on ...

  8. Propensity to Obesity Impacts the Neuronal Response to Energy Imbalance

    PubMed Central

    Cornier, Marc-Andre; McFadden, Kristina L.; Thomas, Elizabeth A.; Bechtell, Jamie L.; Bessesen, Daniel H.; Tregellas, Jason R.

    2015-01-01

    The mechanisms responsible for the propensity to gain weight or remain normal weight are poorly understood. The objective of this study was to study the neuronal response to visual food cues during short-term energy imbalance in healthy adults recruited as obesity-resistant (OR) or obesity-prone (OP) based on self-identification, body mass index, and personal/family weight history. Twenty-five OR and 28 OP subjects were studied in underfed (UF) and overfed (OF) as compared to eucaloric (EU) conditions in a randomized crossover design. Each study phase included a 3-day run-in diet, 1?day of controlled feeding (basal energy needs for EU, 40% above/below basal energy needs for OF/UF), and a test day. On the test day, fMRI was performed in the acute fed stated (30?min after a test meal) while subjects viewed images of foods of high hedonic value and neutral non-food objects. Measures of appetite and hormones were also performed before and every 30?min after the test meal. UF was associated with significantly increased activation of insula, somatosensory cortex, inferior and medial prefrontal cortex (PFC), parahippocampus, precuneus, cingulate, and visual cortex in OR. However, UF had no impact in OP. As a result, UF was associated with significantly greater activation, specifically in the insula, inferior PFC, and somatosensory cortex in OR as compared to OP. While OF was overall associated with reduced activation of inferior visual cortex, no group interaction was observed with OF. In summary, these findings suggest that individuals resistant to weight gain and obesity are more sensitive to short-term energy imbalance, particularly with UF, than those prone to weight gain. The inability to sense or adapt to changes in energy balance may represent an important mechanism contributing to excess energy intake and risk for obesity. PMID:25767441

  9. Na+ and K+ ion imbalances in Alzheimer’s disease

    PubMed Central

    Vitvitsky, Victor M.; Garg, Sanjay K.; Keep, Richard F.; Albin, Roger L.; Banerjee, Ruma

    2012-01-01

    Alzheimer’s disease (AD) is associated with impaired glutamate clearance and depressed Na+/K+ ATPase levels in AD brain that might lead to a cellular ion imbalance. To test this hypothesis, [Na+] and [K+] were analyzed in postmortem brain samples of 12 normal and 16 AD individuals, and in cerebrospinal fluid (CSF) from AD patients and matched controls. Statistically significant increases in [Na+] in frontal (25%) and parietal cortex (20%) and in cerebellar [K+] (15%) were observed in AD samples compared to controls. CSF from AD patients and matched controls exhibited no differences, suggesting that tissue ion imbalances reflected changes in the intracellular compartment. Differences in cation concentrations between normal and AD brain samples were modeled by a 2-fold increase in intracellular [Na+] and an 8–15% increase in intracellular [K+]. Since amyloid beta peptide (A?) is an important contributor to AD brain pathology, we assessed how A? affects ion homeostasis in primary murine astrocytes, the most abundant cells in brain tissue. We demonstrate that treatment of astrocytes with the A? 25–35 peptide increases intracellular levels of Na+ (~2–3-fold) and K+ (~1.5-fold), which were associated with reduced levels of Na+/K+ ATPase and the Na+-dependent glutamate transporters, GLAST and GLT-1. Similar increases in astrocytic Na+ and K+ levels were also caused by A? 1–40, but not by A? 1–42 treatment. Our study suggests a previously unrecognized impairment in AD brain cell ion homeostasis that might be triggered by A? and could significantly affect electrophysiological activity of brain cells, contributing to the pathophysiology of AD. PMID:22820549

  10. Propensity to obesity impacts the neuronal response to energy imbalance.

    PubMed

    Cornier, Marc-Andre; McFadden, Kristina L; Thomas, Elizabeth A; Bechtell, Jamie L; Bessesen, Daniel H; Tregellas, Jason R

    2015-01-01

    The mechanisms responsible for the propensity to gain weight or remain normal weight are poorly understood. The objective of this study was to study the neuronal response to visual food cues during short-term energy imbalance in healthy adults recruited as obesity-resistant (OR) or obesity-prone (OP) based on self-identification, body mass index, and personal/family weight history. Twenty-five OR and 28 OP subjects were studied in underfed (UF) and overfed (OF) as compared to eucaloric (EU) conditions in a randomized crossover design. Each study phase included a 3-day run-in diet, 1?day of controlled feeding (basal energy needs for EU, 40% above/below basal energy needs for OF/UF), and a test day. On the test day, fMRI was performed in the acute fed stated (30?min after a test meal) while subjects viewed images of foods of high hedonic value and neutral non-food objects. Measures of appetite and hormones were also performed before and every 30?min after the test meal. UF was associated with significantly increased activation of insula, somatosensory cortex, inferior and medial prefrontal cortex (PFC), parahippocampus, precuneus, cingulate, and visual cortex in OR. However, UF had no impact in OP. As a result, UF was associated with significantly greater activation, specifically in the insula, inferior PFC, and somatosensory cortex in OR as compared to OP. While OF was overall associated with reduced activation of inferior visual cortex, no group interaction was observed with OF. In summary, these findings suggest that individuals resistant to weight gain and obesity are more sensitive to short-term energy imbalance, particularly with UF, than those prone to weight gain. The inability to sense or adapt to changes in energy balance may represent an important mechanism contributing to excess energy intake and risk for obesity. PMID:25767441

  11. 46 CFR 38.20-10 - Ventilation-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Ventilation-T/ALL. 38.20-10 Section 38.20-10 Shipping... Ventilation § 38.20-10 Ventilation—T/ALL. (a) A power ventilation system shall be provided for compartments... equipped with power ventilation of the exhaust type having capacity sufficient to effect a complete...

  12. 46 CFR 38.20-10 - Ventilation-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Ventilation-T/ALL. 38.20-10 Section 38.20-10 Shipping... Ventilation § 38.20-10 Ventilation—T/ALL. (a) A power ventilation system shall be provided for compartments... equipped with power ventilation of the exhaust type having capacity sufficient to effect a complete...

  13. 46 CFR 38.20-10 - Ventilation-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Ventilation-T/ALL. 38.20-10 Section 38.20-10 Shipping... Ventilation § 38.20-10 Ventilation—T/ALL. (a) A power ventilation system shall be provided for compartments... equipped with power ventilation of the exhaust type having capacity sufficient to effect a complete...

  14. Temporal and concentration effects of isoflurane anaesthesia on intestinal tissue oxygenation and perfusion in horses.

    PubMed

    Hopster, K; Hopster-Iversen, C; Geburek, F; Rohn, K; Kästner, S B R

    2015-07-01

    The aim of this study was to assess the effect of duration of anaesthesia and concentration of isoflurane on global perfusion as well as intestinal microperfusion and oxygenation. Nine Warmblood horses were premedicated with xylazine; anaesthesia was induced with midazolam and ketamine, and maintained with isoflurane. Horses were ventilated to normocapnia. During 7?h of anaesthesia, mean arterial blood pressures (MAP), heart rate, central venous pressure, pulmonary artery pressure, expiratory isoflurane concentration (ETIso) and cardiac output using lithium dilution were measured; cardiac index (CI) was calculated. Intestinal microperfusion and oxygenation were measured using laser Doppler flowmetry and white-light spectrophotometry. Surface probes were placed via median laparotomy on the serosal and mucosal site of the jejunum and the pelvic flexion of the colon. After 3?h of constant ETIso (1.4%), ETIso was increased in 0.2% increments up to 2.4%, followed by a decrease to 1.2% and an increase to 1.4%. The CI and MAP decreased continuously with increasing ETIso to 40?±?5?mL/kg/min and 52?±?8?mmHg, respectively. Microperfusion and oxygenation remained unchanged until an ETIso of 2.0% resulted in CI and MAP of 48?±?5?mL/kg/min and 62?±?6?mmHg, respectively, and then decreased rapidly. When ETIso decreased back to baseline, CI, MAP, microperfusion and oxygenation recovered to baseline. Isoflurane concentration but not duration of isoflurane anaesthesia influenced central and intestinal oxygenation and perfusion in healthy horses. Under isoflurane, intestinal perfusion appeared to be preserved until a threshold MAP or blood flow was reached. PMID:25986133

  15. Racial differences in withdrawal of mechanical ventilation do not alter mortality in neurologically injured patients?

    PubMed Central

    Rubin, Michael A.; Dhar, Rajat; Diringer, Michael N.

    2013-01-01

    Purpose Racial differences in withdrawal of mechanical ventilation (WMV) have been demonstrated among patients with severe neurologic injuries. We ascertained whether such differences might be accounted for by imbalances in socioeconomic status or disease severity, and whether such racial differences impact hospital mortality or result in greater discharge to long-term care facilities. Materials and methods We evaluated WMV among 1885 mechanically ventilated patients with severe neurologic injury (defined as Glasgow Coma Scale <9), excluding those progressing to brain death within the first 48 hours. Results Withdrawal of mechanical ventilation was less likely in nonwhite patients (22% vs 31%, P < .001). Nonwhites were younger and were more likely to have Medicaid or no insurance, live in ZIP codes with low median household incomes, be unmarried, and have greater illness severity; but after adjustment for these variables, racial difference in WMV persisted (odds ratio, 0.56; 95% confidence interval, 0.42–0.76). Nonwhite patients were more likely to die instead with full support or progress to brain death, resulting in equivalent overall hospital mortality (40% vs 42%, P = .44). Among survivors, nonwhites were more likely to be discharged to long-term care facilities (27% vs 17%, P < .001). Conclusions Surrogates of nonwhite neurologically injured patients chose WMV less often even after correcting for socioeconomic status and other confounders. This difference in end-of-life decision making does not appear to alter hospital mortality but may result in more survivors left in a disabled state. PMID:24120091

  16. Particle deposition in ventilation ducts

    SciTech Connect

    Sippola, Mark R.

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 {micro}m were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on the experimental measurements was applied to evaluate particle losses in supply and return duct runs. Model results suggest that duct losses are negligible for particle sizes less than 1 {micro}m and complete for particle sizes greater than 50 {micro}m. Deposition to insulated ducts, horizontal duct floors and bends are predicted to control losses in duct systems. When combined with models for HVAC filtration and deposition to indoor surfaces to predict the ultimate fates of particles within buildings, these results suggest that ventilation ducts play only a small role in determining indoor particle concentrations, especially when HVAC filtration is present. However, the measured and modeled particle deposition rates are expected to be important for ventilation system contamination.

  17. Ventilation above closing volume reduces pulmonary vascular resistance hysteresis.

    PubMed

    Creamer, K M; McCloud, L L; Fisher, L E; Ehrhart, I C

    1998-10-01

    The aim of this study was to determine the relationship of pulmonary vascular resistance (PVR) hysteresis and lung volume, with special attention to the effects of ventilation around closing volume (CV). Isolated, blood-perfused canine left lower lung lobes (LLL) were incrementally inflated and deflated. Airway and pulmonary artery pressures (PAP) were recorded after each stepwise volume change. Constant blood flow was provided (600 ml/min) and the pulmonary vein pressure (PVP) was held constant at 5 cm H2O. PAP changes, therefore, were a direct index of PVR changes. Group 1 lobes underwent a full inflation from complete collapse to total lobe capacity (TLC) followed by a full deflation. Group 2 lobes underwent two deflation/inflation cycles, after an initial full inflation. These cycles, both beginning at TLC, had deflation end above and below CV, respectively. Significant PVR hysteresis was noted when the first inflation and deflation were compared. The maximum difference in PAP on deflation was 3.3 cm H2O or 11%. The mean decrease was 2.7 cm H2O for 18 lobes (p < 0.0001). The PAPs on all subsequent inflations or deflations that began above CV remained 9% lower than the initial inflation (n = 9, p < 0.0001), but were not different from each other. However, the final inflation which began from below CV resulted in a 30% return of PVR hysteresis (mean increase in PAP of 0.8 cm H2O, n = 7, p < 0.004). We conclude that there is hysteresis in the PVR response during ventilation, with decreased PVR during deflation relative to the initial inflation, that this hysteresis is absent when lung volume is maintained greater than CV, and that hysteresis returns when inflation occurs after deflation below CV. PMID:9769269

  18. Wife Beating in South Africa: An Imbalance Theory of Resources and Power

    ERIC Educational Resources Information Center

    Choi, Susanne Y. P.; Ting, Kwok-Fai

    2008-01-01

    This article develops an imbalance theory to explain physical violence against women in intimate relationships in South Africa. The theory proposes four typologies: dependence, compensation, submission, and transgression, through which imbalances in resource contribution and power distribution between spouses are hypothesized to contribute to…

  19. Extended use of hemofiltration and high perfusion flow rate in cardiopulmonary bypass improves perioperative fluid balance in neonates and infants.

    PubMed

    Sakurai, H; Maeda, M; Sai, N; Miyahara, K; Nakayama, M; Hasegawa, H; Hayakawa, M

    1999-04-01

    We evaluated the efficacy of the extended use of hemofiltration (EHF) and high perfusion flow rate in cardiopulmonary bypass (CPB) in pediatric open-heart surgery retrospectively. In the EHF method, hemofiltration was used for hemic prime before initiation of the bypass and ultrafiltration was used throughout the bypass. Thirty-four children, with transposition of great arteries who were undergoing arterial switch operation with the use of hemic prime, were subjects of this study. They were divided into 2 groups, a control group (n = 16) and a group (n = 18) that underwent EHF. There were no significant differences between groups in demographics, but the maximum perfusion index and lowest rectal temperature were higher in the EHF group. This study compared urination during bypass, arterial oxygen pressure at the end of bypass and operation, the duration of the ventilation, and postoperative soft tissue index (STI) expressing the severity of edema. In the EHF group, urination during bypass was significantly higher, and there was a tendency to higher arterial oxygen pressure. The patients in the EHF group were weaned from the ventilator significantly earlier. Postoperative STI was significantly higher, so edema was more severe in the control group. We consider that the use of EHF and a high perfusion flow rate in CPB are an ideal method to improve the perioperative fluid balance in pediatric open-heart surgery. We suspect that these good clinical effects result from maintaining the inflammatory mediators at a low level throughout the bypass, reducing the following release of the mediators and attenuating the interaction of the mediators. PMID:10332112

  20. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except...

  1. Perfusion computed tomography in renal cell carcinoma

    PubMed Central

    Das, Chandan J; Thingujam, Usha; Panda, Ananya; Sharma, Sanjay; Gupta, Arun Kumar

    2015-01-01

    Various imaging modalities are available for the diagnosis, staging and response evaluation of patients with renal cell carcinoma (RCC). While contrast enhanced computed tomography (CT) is used as the standard of imaging for size, morphological evaluation and response assessment in RCC, a new functional imaging technique like perfusion CT (pCT), goes down to the molecular level and provides new perspectives in imaging of RCC. pCT depicts regional tumor perfusion and vascular permeability which are indirect parameters of tumor angiogenesis and thereby provides vital information regarding tumor microenvironment. Also response evaluation using pCT may predate the size criteria used in Response Evaluation Criteria in Solid Tumors, as changes in the perfusion occurs earlier following tissue kinase inhibitors before any actual change in size. This may potentially help in predicting prognosis, better selection of therapy and more accurate and better response evaluation in patients with RCC. This article describes the techniques and role of pCT in staging and response assessment in patients with RCCs. PMID:26217456

  2. Regulation of skeletal muscle perfusion during exercise

    NASA Technical Reports Server (NTRS)

    Delp, M. D.; Laughlin, M. H.

    1998-01-01

    For exercise to be sustained, it is essential that adequate blood flow be provided to skeletal muscle. The local vascular control mechanisms involved in regulating muscle perfusion during exercise include metabolic control, endothelium-mediated control, propagated responses, myogenic control, and the muscle pump. The primary determinant of muscle perfusion during sustained exercise is the metabolic rate of the muscle. Metabolites from contracting muscle diffuse to resistance arterioles and act directly to induce vasodilation, or indirectly to inhibit noradrenaline release from sympathetic nerve endings and oppose alpha-adrenoreceptor-mediated vasoconstriction. The vascular endothelium also releases vasodilator substances (e.g., prostacyclin and nitric oxide) that are prominent in establishing basal vascular tone, but these substances do not appear to contribute to the exercise hyperemia in muscle. Endothelial and smooth muscle cells may also be involved in propagating vasodilator signals along arterioles to parent and daughter vessels. Myogenic autoregulation does not appear to be involved in the exercise hyperemia in muscle, but the rhythmic propulsion of blood from skeletal muscle veins facilitates venous return to the heart and muscle perfusion. It appears that the primary determinants of sustained exercise hyperemia in skeletal muscle are metabolic vasodilation and increased vascular conductance via the muscle pump. Additionally, sympathetic neural control is important in regulating muscle blood flow during exercise.

  3. Lung perfusion imaging with monosized biodegradable microspheres.

    PubMed

    Häfeli, Urs O; Saatchi, Katayoun; Elischer, Philipp; Misri, Ripen; Bokharaei, Mehrdad; Labiris, N Renée; Stoeber, Boris

    2010-03-01

    After intravenous injection, particles larger than red blood cells will be trapped in the first capillary bed that they encounter. This is the principle of lung perfusion imaging in nuclear medicine, where macroaggregated albumin (MAA) is radiolabeled with (99m)Tc, infused into a patient's arm vein, and then imaged with gamma scintigraphy. Our aim was to evaluate if monosized microspheres could replace (99m)Tc-MAA. Biodegradable poly(L-lactide) microspheres containing chelating bis(picolylamine) end groups were prepared by a flow focusing method on a microfluidic glass chip and were of highly homogeneous size (9.0 +/- 0.4 microm). The microspheres were radiolabeled with [(99m)Tc(H(2)O)(3)(CO)(3)](+) and then evaluated in mice for lung perfusion imaging. Fifteen minutes after injection, 79.6 +/- 3.8% of the injected activity was trapped in the lungs of mice. Monosized biodegradable radioactive microspheres are, thus, appropriate lung perfusion imaging agents. Other sizes of these highly uniform microspheres have the potential to improve diagnostic and therapeutic approaches in diverse areas of medicine. PMID:20143805

  4. Modeling perfusion in the cerebral vasculature.

    PubMed

    David, T; Moore, S

    2008-12-01

    The constant perfusion of a human organ with nutrients and oxygen demands a robust regulatory mechanisms in the face of normal day-to-day pressure variations in the vasculature. The brain, in a similar manner to the heart requires this mechanism to be extremely quick acting, relative to other ways of altering perfusion such as varying systemic blood pressure, since oxygen depravation in the tissues of the brain can be tolerated for only of the order of tens of seconds before significant damage can be done. In recent years computational models, and it must be noted computer architecture have evolved to an extent where mathematicians and engineers can play a large part in discovering how the brain functions physiologically as well as investigating pathological conditions. This review will look at a number of increasingly complex computational models of blood flow to the brain and how variations in arterial geometry can influence the perfusion in the cerebral vasculature. Although these models have provided an insight into complex mechanisms the research area is densely populated with important questions that perhaps only computer models can answer. The review will indicate possible areas of investigation. PMID:18980854

  5. Phosphorus NMR of isolated perfused morris hepatomas

    SciTech Connect

    Graham, R.A.; Meyer, R.A.; Brown, T.R.; Sauer, L.A.

    1986-03-05

    The authors are developing techniques for the study of perfused solid tumors by NMR. Tissue-isolated solid hepatomas were grown to 1-2 cm diameter as described previously. The arterial supply was isolated and the tumors perfused (0.5 - 1.0 ml/min) in vitro at 25 C with a 15% suspension of red blood cells in Krebs-Henseliet solution. /sup 31/P-NMR spectra were acquired at 162 MHz in a specially-designed NMR probe using a solenoidal coil. Intracellular pH (monitored from the chemical shift of inorganic phosphate) and ATP levels were stable for up to 6 hrs during perfusion. During 30 min of global ischemia, ATP decreased by 75% and pH fell from 7.0 to 6.7. These changes were reversed by 1 hr reperfusion. In addition to ATP and phosphate, the spectra included a large resonance due to phosphomonoesters, as well as peaks consistent with glycerylphosphocholine, glyceryl-phosphoethanolamine, phosphocreatine, NAD, and UDPG. However, the most novel feature of the spectra was the presence of an unidentified peak in the phosphonate region (+ 16.9 ppm). The peak was not present in spectra of muscle, liver, brain, kidney, or fat tissues excised from the same animals. They are presently attempting to identify the compound that gives rise to this peak and to establish its metabolic origin.

  6. Whole Animal Perfusion Fixation for Rodents

    PubMed Central

    Gage, Gregory J.; Kipke, Daryl R.; Shain, William

    2012-01-01

    The goal of fixation is to rapidly and uniformly preserve tissue in a life-like state. While placing tissue directly in fixative works well for small pieces of tissue, larger specimens like the intact brain pose a problem for immersion fixation because the fixative does not reach all regions of the tissue at the same rate 5,7. Often, changes in response to hypoxia begin before the tissue can be preserved 12. The advantage of directly perfusing fixative through the circulatory system is that the chemical can quickly reach every corner of the organism using the natural vascular network. In order to utilize the circulatory system most effectively, care must be taken to match physiological pressures 3. It is important to note that physiological pressures are dependent on the species used. Techniques for perfusion fixation vary depending on the tissue to be fixed and how the tissue will be processed following fixation. In this video, we describe a low-cost, rapid, controlled and uniform fixation procedure using 4% paraformaldehyde perfused via the vascular system: through the heart of the rat to obtain the best possible preservation of the brain for immunohistochemistry. The main advantage of this technique (vs. gravity-fed systems) is that the circulatory system is utilized most effectively. PMID:22871843

  7. Perfusion Phantom: An Efficient and Reproducible Method to Simulate Myocardial First-Pass Perfusion Measurements with Cardiovascular Magnetic Resonance

    PubMed Central

    Chiribiri, Amedeo; Schuster, Andreas; Ishida, Masaki; Hautvast, Gilion; Zarinabad, Niloufar; Morton, Geraint; Otton, James; Plein, Sven; Breeuwer, Marcel; Batchelor, Philip; Schaeffter, Tobias; Nagel, Eike

    2013-01-01

    The aim of this article is to describe a novel hardware perfusion phantom that simulates myocardial first-pass perfusion allowing comparisons between different MR techniques and validation of the results against a true gold standard. MR perfusion images were acquired at different myocardial perfusion rates and variable doses of gadolinium and cardiac output. The system proved to be sensitive to controlled variations of myocardial perfusion rate, contrast agent dose, and cardiac output. It produced distinct signal intensity curves for perfusion rates ranging from 1 to 10 mL/mL/min. Quantification of myocardial blood flow by signal deconvolution techniques provided accurate measurements of perfusion. The phantom also proved to be very reproducible between different sessions and different operators. This novel hardware perfusion phantom system allows reliable, reproducible, and efficient simulation of myocardial first-pass MR perfusion. Direct comparison between the results of image-based quantification and reference values of flow and myocardial perfusion will allow development and validation of accurate quantification methods. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc. PMID:22532435

  8. Maintenance Guide for Greenhouse Ventilation, Evaporative Cooling Heating Systems1

    E-print Network

    Hill, Jeffrey E.

    AE26 Maintenance Guide for Greenhouse Ventilation, Evaporative Cooling Heating Systems1 D. E and preventive maintenance procedures for ventilation, evaporative cooling and heating systems. Ventilation from evaporative cooling pads, high heating expenses, heavy condensation in winter, reduced life

  9. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Special cargo pumproom ventilation rate. 153.316 Section 153.316...Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table 1 refers to...

  10. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop...

  11. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation of gasoline machinery spaces...Operating Requirements § 185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space,...

  12. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Special cargo pumproom ventilation rate. 153.316 Section 153.316...Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table 1 refers to...

  13. 46 CFR 127.260 - Ventilation for accommodations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation for accommodations. 127.260 ...Construction and Arrangements § 127.260 Ventilation for accommodations. (a) Each...tons must be provided with a mechanical ventilation system unless the cognizant OCMI...

  14. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation of gasoline machinery spaces...Operating Requirements § 185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space,...

  15. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Venting, ventilation and combustion air. 3280.710 ...Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting...instructions. Gravity or mechanical ventilation shall be installed within a...

  16. 21 CFR 888.4230 - Cement ventilation tube.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Cement ventilation tube. 888.4230 Section 888.4230...Surgical Devices § 888.4230 Cement ventilation tube. (a) Identification. A cement ventilation tube is a tube-like device...

  17. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Special cargo pumproom ventilation rate. 153.316 Section 153.316...Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table 1 refers to...

  18. 21 CFR 888.4230 - Cement ventilation tube.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Cement ventilation tube. 888.4230 Section 888.4230...Surgical Devices § 888.4230 Cement ventilation tube. (a) Identification. A cement ventilation tube is a tube-like device...

  19. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Venting, ventilation and combustion air. 3280.710 ...Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting...instructions. Gravity or mechanical ventilation shall be installed within a...

  20. 33 CFR 183.630 - Standards for natural ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Standards for natural ventilation. 183.630 Section 183.630 Navigation...SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.630 Standards for natural ventilation. (a) For the purpose of §...

  1. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...false Vaults: Sealing, venting, and ventilation. 192.187 Section 192.187 ...187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed...millimeters) in diameter; (2) The ventilation must be enough to minimize the...

  2. 46 CFR 154.1200 - Mechanical ventilation system: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Mechanical ventilation system: General. 154.1200 Section...and Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a) Each...

  3. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Special cargo pumproom ventilation rate. 153.316 Section 153.316...Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table 1 refers to...

  4. 24 CFR 3280.103 - Light and ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Light and ventilation. 3280.103 Section 3280.103...Considerations § 3280.103 Light and ventilation. (a) Lighting. Each habitable...whichever is greater. (b) Whole-house ventilation. Each manufactured home must be...

  5. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...false Vaults: Sealing, venting, and ventilation. 192.187 Section 192.187 ...187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed...millimeters) in diameter; (2) The ventilation must be enough to minimize the...

  6. 33 CFR 183.630 - Standards for natural ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Standards for natural ventilation. 183.630 Section 183.630 Navigation...SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.630 Standards for natural ventilation. (a) For the purpose of §...

  7. 46 CFR 169.315 - Ventilation (other than machinery spaces).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation (other than machinery spaces). ...Arrangement Hull Structure § 169.315 Ventilation (other than machinery spaces). ...natural system will provide adequate ventilation in all ordinary weather...

  8. 46 CFR 127.260 - Ventilation for accommodations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation for accommodations. 127.260 ...Construction and Arrangements § 127.260 Ventilation for accommodations. (a) Each...tons must be provided with a mechanical ventilation system unless the cognizant OCMI...

  9. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop...

  10. 14 CFR 27.1187 - Ventilation and drainage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Ventilation and drainage. 27.1187 Section...Powerplant Fire Protection § 27.1187 Ventilation and drainage. Each compartment...installation must have provision for ventilation and drainage of flammable fluids....

  11. 24 CFR 3280.103 - Light and ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Light and ventilation. 3280.103 Section 3280.103...Considerations § 3280.103 Light and ventilation. (a) Lighting. Each habitable...whichever is greater. (b) Whole-house ventilation. Each manufactured home must be...

  12. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Venting, ventilation and combustion air. 3280.710 ...Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting...instructions. Gravity or mechanical ventilation shall be installed within a...

  13. 33 CFR 183.630 - Standards for natural ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Standards for natural ventilation. 183.630 Section 183.630 Navigation...SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.630 Standards for natural ventilation. (a) For the purpose of §...

  14. 46 CFR 127.260 - Ventilation for accommodations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation for accommodations. 127.260 ...Construction and Arrangements § 127.260 Ventilation for accommodations. (a) Each...tons must be provided with a mechanical ventilation system unless the cognizant OCMI...

  15. 21 CFR 888.4230 - Cement ventilation tube.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Cement ventilation tube. 888.4230 Section 888.4230...Surgical Devices § 888.4230 Cement ventilation tube. (a) Identification. A cement ventilation tube is a tube-like device...

  16. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop...

  17. 46 CFR 154.1200 - Mechanical ventilation system: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Mechanical ventilation system: General. 154.1200 Section...and Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a) Each...

  18. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...false Vaults: Sealing, venting, and ventilation. 192.187 Section 192.187 ...187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed...millimeters) in diameter; (2) The ventilation must be enough to minimize the...

  19. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation of gasoline machinery spaces...Operating Requirements § 185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space,...

  20. 14 CFR 27.1187 - Ventilation and drainage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Ventilation and drainage. 27.1187 Section...Powerplant Fire Protection § 27.1187 Ventilation and drainage. Each compartment...installation must have provision for ventilation and drainage of flammable fluids....

  1. 33 CFR 183.630 - Standards for natural ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Standards for natural ventilation. 183.630 Section 183.630 Navigation...SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.630 Standards for natural ventilation. (a) For the purpose of §...

  2. 33 CFR 183.630 - Standards for natural ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Standards for natural ventilation. 183.630 Section 183.630 Navigation...SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.630 Standards for natural ventilation. (a) For the purpose of §...

  3. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation of gasoline machinery spaces...Operating Requirements § 185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space,...

  4. 46 CFR 154.1200 - Mechanical ventilation system: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Mechanical ventilation system: General. 154.1200 Section...and Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a) Each...

  5. 14 CFR 27.1187 - Ventilation and drainage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Ventilation and drainage. 27.1187 Section...Powerplant Fire Protection § 27.1187 Ventilation and drainage. Each compartment...installation must have provision for ventilation and drainage of flammable fluids....

  6. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Vaults: Sealing, venting, and ventilation. 192.187 Section 192.187 ...187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed...millimeters) in diameter; (2) The ventilation must be enough to minimize the...

  7. 46 CFR 111.106-15 - Ventilation of hazardous locations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation of hazardous locations. 111.106-15...Locations on OSVs § 111.106-15 Ventilation of hazardous locations. (a) The ventilation design principles must comply with...

  8. 24 CFR 3280.103 - Light and ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Light and ventilation. 3280.103 Section 3280.103...Considerations § 3280.103 Light and ventilation. (a) Lighting. Each habitable...whichever is greater. (b) Whole-house ventilation. Each manufactured home must be...

  9. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Venting, ventilation and combustion air. 3280.710 ...Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting...instructions. Gravity or mechanical ventilation shall be installed within a...

  10. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop...

  11. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Venting, ventilation and combustion air. 3280.710 ...Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting...instructions. Gravity or mechanical ventilation shall be installed within a...

  12. 46 CFR 127.260 - Ventilation for accommodations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation for accommodations. 127.260 ...Construction and Arrangements § 127.260 Ventilation for accommodations. (a) Each...tons must be provided with a mechanical ventilation system unless the cognizant OCMI...

  13. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...false Vaults: Sealing, venting, and ventilation. 192.187 Section 192.187 ...187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed...millimeters) in diameter; (2) The ventilation must be enough to minimize the...

  14. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Special cargo pumproom ventilation rate. 153.316 Section 153.316...Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table 1 refers to...

  15. 46 CFR 169.315 - Ventilation (other than machinery spaces).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation (other than machinery spaces). ...Arrangement Hull Structure § 169.315 Ventilation (other than machinery spaces). ...natural system will provide adequate ventilation in all ordinary weather...

  16. 46 CFR 154.1200 - Mechanical ventilation system: General.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Mechanical ventilation system: General. 154.1200 Section...and Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a) Each...

  17. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation of gasoline machinery spaces...Operating Requirements § 185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space,...

  18. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop...

  19. 24 CFR 3280.103 - Light and ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Light and ventilation. 3280.103 Section 3280.103...Considerations § 3280.103 Light and ventilation. (a) Lighting. Each habitable...whichever is greater. (b) Whole-house ventilation. Each manufactured home must be...

  20. 46 CFR 127.260 - Ventilation for accommodations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation for accommodations. 127.260 ...Construction and Arrangements § 127.260 Ventilation for accommodations. (a) Each...tons must be provided with a mechanical ventilation system unless the cognizant OCMI...

  1. 24 CFR 3280.103 - Light and ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Light and ventilation. 3280.103 Section 3280.103...Considerations § 3280.103 Light and ventilation. (a) Lighting. Each habitable...whichever is greater. (b) Whole-house ventilation. Each manufactured home must be...

  2. 21 CFR 888.4230 - Cement ventilation tube.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Cement ventilation tube. 888.4230 Section 888.4230...Surgical Devices § 888.4230 Cement ventilation tube. (a) Identification. A cement ventilation tube is a tube-like device...

  3. 21 CFR 888.4230 - Cement ventilation tube.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Cement ventilation tube. 888.4230 Section 888.4230...Surgical Devices § 888.4230 Cement ventilation tube. (a) Identification. A cement ventilation tube is a tube-like device...

  4. Regional perfusion with cis-platinum and dacarbazine.

    PubMed

    Aigner, K; Hild, P; Henneking, K; Paul, E; Hundeiker, M

    1983-01-01

    In 22 patients isolated extremity perfusion with cis-platinum for treatment of malignant melanoma was performed; 18 had local metastastic disease (M. D. Anderson stages II and III A, B, AB) and four were stage I. A further five patients were submitted to isolated DTIC perfusion. DTIC-perfused tumors showed regression rates of 30%-80%, followed by recurrences within 4 months. After cis-platinum perfusion stage-III AB cases tended to show tumor recurrence within 4 months, while to date stage-III A and stage-II cases have reached disease-free survival times of 17 and 20 months respectively. While in DTIC perfusion the tissue temperature may range between 40 degrees and 41 degrees C, in cis-platinum perfusions 40 degrees C should not be exceeded; otherwise neural damage will occur. PMID:6685902

  5. CT Perfusion Dynamics of Intracranial Tuberculomas

    PubMed Central

    N., Jayakumar Peruvumba; Shivashankar, Ravishankar

    2015-01-01

    Aims To study perfusion characteristics of intracranial tuberculomas and analyze changes with anti tubercular treatment. Materials and Methods Nineteen patients of histologically proven intracranial tuberculomas were included in the study of which 9 were not on antitubercular treatment and ten were on antitubercular treatment (6 patients on treatment for less than 2 months and 4 were more than 6 months). All patients underwent CT perfusion (CTP) and CTP parameters like rCBV and rCBF were obtained from entire lesion, center and capsule of lesions and compared. Results CTP parameters like rCBF and rCBV were significantly low in all the three ROIs in the group not on treatment compared to that of on treatment ; rCBF and rCBV of entire lesion (p=0.018 and p=0.005 respectively), capsule (p=0.045 and p=0.010 respectively) and center of the lesion (p=0.020 and p=0.009) respectively). Tuberculomas on antitubercular treatment of more than six months showed reduced rCBF and rCBV in entire lesion (p=0.01 & p=0.01 respectively), capsule (p=0.04 & p=0.03 respectively) and center (p=0.08 & p=0.05 respectively) compared to those on treatment for less than two months. Similarly tuberculomas on treatment for six months did not show significant difference in rCBF and rCBV compared to tuberculomas who were not on treatment. Tuberculomas on treatment for less than two months showed statistically increased rCBF and rCBV in entire lesion (p=0.01 & p=0.04 respectively), capsule (p=0.03 & p=0.01 respectively) and center (p= 0.03 &=0.01) compared to those not on treatment. Conclusion Intracranial tuberculomas not on treatment and those on treatment for around six months show low perfusion and tuberculomas on treatment for less than two months show high perfusion. These findings suggest that serial perfusion profiles of tuberculomas on treatment could possibly be seen as surrogate markers of response to treatment. PMID:26155528

  6. HOW THE LEED VENTILATION CREDIT IMPACTS ENERGY CONSUMPTION OF GSHP SYSTEMS A CASE STUDY FOR PRIMARY SCHOOLS

    SciTech Connect

    Liu, Xiaobing

    2011-01-01

    This paper presents a study on the impacts of increased outdoor air (OA) ventilation on the performance of ground-source heat pump (GSHP) systems that heat and cool typical primary schools. Four locations Phoenix, Miami, Seattle, and Chicago are selected in this study to represent different climate zones in the United States. eQUEST, an integrated building and HVAC system energy analysis program, is used to simulate a typical primary school and the GSHP system at the four locations with minimum and 30% more than minimum OA ventilation. The simulation results show that, without an energy recovery ventilator, the 30% more OA ventilation results in an 8.0 13.3% increase in total GSHP system energy consumption at the four locations. The peak heating and cooling loads increase by 20.2 30% and 14.9 18.4%, respectively, at the four locations. The load imbalance of the ground heat exchanger is increased in hot climates but reduced in mild and cold climates.

  7. A Report of Perfusion Staffing Survey: Decision Factors That Influence Staffing of Perfusion Teams

    PubMed Central

    Conliffe, Jacqueline A.; Riley, Jeffrey B.; Clutter, Jill; Wolf, Kay; Murtha, Sean

    2007-01-01

    Abstract: Health care organizations are becoming increasingly aware of the issues surrounding safe staffing because it affects all of us: the patient, public, profession, policy makers, and employers. The conduct of perfusion has been researched, but environmental factors surrounding perfusion have not. The intent of this study was to identify the current perfusion staff to case ratio, the decision factors used to make staffing decisions, and the relative importance of the factors to staff requirements. A survey instrument was constructed. The questionnaire contained four sections: Hospital Information, Perfusionist Information, Staffing Information, and Additional Feedback. Questionnaires were electronically mailed to American Society of Extracorporeal Society (AmSECT) members who were registered on Perflist. Response rate was monitored, and a follow-up survey was sent. Unfortunately, respondents were not compared statistically with the population on like characteristics, because AmSECT does not currently have information regarding the characteristics of their PerfList members. The staff to perfusion case ratio for 2006 was 120 ± 46 (SD) cases. The top three factors used by perfusionists to determine the number of staff to hire were the number of heart cases, on-call requirements, and the number of operating rooms. The reported use and importance of the decision factors did not differ significantly when reported by chief perfusionists, clinical perfusionists, or those who reported being involved in staffing. On-call requirements were reported to be used significantly more by chief perfusionists and by high activity perfusion teams when determining the number of staff to hire. Small hospitals tended to use staff experience, medium-sized hospitals reported using the number of operating rooms more often, and larger hospitals used the number of hospitals covered to determine staff requirements. Staffing a perfusion team is a difficult task, and many factors need to be considered. This survey provided a description of the current managerial staffing environment and practice. Further research surrounding the application of these factors to staff scheduling is needed. PMID:18293811

  8. The man-made creators of the imbalance of water in Nature

    NASA Astrophysics Data System (ADS)

    Shlafman, L. M.; Kontar, V. A.

    2013-12-01

    At 2011 we have described the imbalance of water in Nature as the system [1]. At 2012 we have described water and carbon and the glaciers [2], [3] as creators of the imbalance of Nature. Now we are describing some man-made creators of the imbalance of Nature. The photosynthesis is a powerful creator of the imbalance of Nature. The photosynthesis significantly increases the complexity of the structures and reduces the entropy. Earth's hydrosphere contains water less than it was flowed via photosynthesis. This is an example of the imbalance of involving when the return of water has delayed because water is involved into the processes of life and other processes. People widely use photosynthesis and create not only an additional man-made imbalance of water in Nature, but also the man-made changing the albedo, and a lot of other important parameters of the planet of Earth. All of these processes are significantly imbalanced. The fossil hydrocarbons have accumulated during millions of years, but now are burned. This is an example of the imbalance delay by time. The man-made burning of the hydrocarbons is creating the imbalances of impact or explosive type, because of the burning processes is in millions of times faster than the accumulation processes. Please pay attention to the imbalance of redeployment by places. For example, oil and gas are extracted in one places, and burned in others. During combustion is standing out not only water, but energy, and other components. The temperature in the centers of big cities is always higher and there is dominating the rising air. It pollutes the environment, changes circulations, create greenhouse effect, etc. Other examples of the imbalance of relocation are shown in the production and consumption of food. The irrigation systems transfer water from one place to another. This transfer of water creates a lot of imbalances in change climate, ecosystems, etc in places where water was took and where the water was brought. Usually these are different places where the water taken, where the water used to grow crops, where the crop had eaten and where waste throw out. It creates a lot of the man-made imbalances of redeployment, which generate the new chains of different types of the man-made imbalances of water, other components and processes. The waste is one of the most important man-made creators of the imbalance of Nature. Some of water from the waste comes back into circulation in the clean or dirty conditions. Another part of water from waste will join into numerous water-based or water-use components of Nature, and fall out of the hydrological cycle for a long time. The quantity and diversity of waste are rising much faster than the recycles industries and it is creating a lot of dangerous imbalances of Nature. The wastes are is the time bombs, which man made, and which will soon explode. The traditional balanced science and practice are not prepared to deal with the waste problem. The concept of the imbalance of Nature can help prevent this catastrophic explosion. People are creating a lot of the man-made imbalances of Nature which bring the dangerous 'unexpected surprises'. The concept of the imbalance of Nature give possibilities to create the man-made imbalances of Nature with the predictable parameters and it can help do Mother Nature to be friendlier to humanity.

  9. Healthcare Technology Management (HTM) of mechanical ventilators by clinical engineers.

    PubMed

    Yoshioka, Jun; Nakane, Masaki; Kawamae, Kaneyuki

    2014-01-01

    Mechanical ventilator failures expose patients to unacceptable risks, and maintaining mechanical ventilator safety is an important issue. We examined the usefulness of maintaining mechanical ventilators by clinical engineers (CEs) using a specialized calibrator. These evaluations and the ability to make in-house repairs proved useful for obviating the need to rent ventilators which, in turn, might prove faulty themselves. The CEs' involvement in maintaining mechanical ventilators is desirable, ensures prompt service, and, most importantly, enhances safe management of mechanical ventilators. PMID:25520839

  10. Whole-brain dynamic CT angiography and perfusion imaging.

    PubMed

    Orrison, W W; Snyder, K V; Hopkins, L N; Roach, C J; Ringdahl, E N; Nazir, R; Hanson, E H

    2011-06-01

    The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain. PMID:21371698

  11. Perfusion Scintigraphy and Patient Selection for Lung Volume Reduction Surgery

    PubMed Central

    Chandra, Divay; Lipson, David A.; Hoffman, Eric A.; Hansen-Flaschen, John; Sciurba, Frank C.; DeCamp, Malcolm M.; Reilly, John J.; Washko, George R.

    2010-01-01

    Rationale: It is unclear if lung perfusion can predict response to lung volume reduction surgery (LVRS). Objectives: To study the role of perfusion scintigraphy in patient selection for LVRS. Methods: We performed an intention-to-treat analysis of 1,045 of 1,218 patients enrolled in the National Emphysema Treatment Trial who were non–high risk for LVRS and had complete perfusion scintigraphy results at baseline. The median follow-up was 6.0 years. Patients were classified as having upper or non–upper lobe–predominant emphysema on visual examination of the chest computed tomography and high or low exercise capacity on cardiopulmonary exercise testing at baseline. Low upper zone perfusion was defined as less than 20% of total lung perfusion distributed to the upper third of both lungs as measured on perfusion scintigraphy. Measurements and Main Results: Among 284 of 1,045 patients with upper lobe–predominant emphysema and low exercise capacity at baseline, the 202 with low upper zone perfusion had lower mortality with LVRS versus medical management (risk ratio [RR], 0.56; P = 0.008) unlike the remaining 82 with high perfusion where mortality was unchanged (RR, 0.97; P = 0.62). Similarly, among 404 of 1,045 patients with upper lobe–predominant emphysema and high exercise capacity, the 278 with low upper zone perfusion had lower mortality with LVRS (RR, 0.70; P = 0.02) unlike the remaining 126 with high perfusion (RR, 1.05; P = 1.00). Among the 357 patients with non–upper lobe–predominant emphysema (75 with low and 282 with high exercise capacity) there was no improvement in survival with LVRS and measurement of upper zone perfusion did not contribute new prognostic information. Conclusions: Compared with optimal medical management, LVRS reduces mortality in patients with upper lobe–predominant emphysema when there is low rather than high perfusion to the upper lung. PMID:20538961

  12. History of Mechanical Ventilation. From Vesalius to Ventilator-induced Lung Injury.

    PubMed

    Slutsky, Arthur S

    2015-05-15

    Mechanical ventilation is a life-saving therapy that catalyzed the development of modern intensive care units. The origins of modern mechanical ventilation can be traced back about five centuries to the seminal work of Andreas Vesalius. This article is a short history of mechanical ventilation, tracing its origins over the centuries to the present day. One of the great advances in ventilatory support over the past few decades has been the development of lung-protective ventilatory strategies, based on our understanding of the iatrogenic consequences of mechanical ventilation such as ventilator-induced lung injury. These strategies have markedly improved clinical outcomes in patients with respiratory failure. PMID:25844759

  13. A pilot study on the refinement of acute inhalation toxicity studies: the isolated perfused rat lung as a screening tool for surface-active substances.

    PubMed

    Fischer, Monika; Koch, Wolfgang; Windt, Horst; Dasenbrock, Clemens

    2012-09-01

    New surface-active agents in waterproofing sprays are frequently tested for acute inhalation toxicity in vivo according to OECD Test Guideline 403. In order to refine and reduce the number of acute inhalation tests performed, we propose a screening test that uses isolated lungs. The test consists of the exposure of isolated, ventilated and perfused rat lungs, to aerosolised formulations of waterproofing agents (mass median aerodynamic diameter = 1?m), and on-line monitoring of respiratory parameters and gross pathology analysis. A pilot evaluation of the isolated perfused rat lung model for use in a screening test was carried out by blind testing 12 surface-active substances. The results obtained compared well with data available from in vivo acute inhalation studies. Substances that triggered harmful effects, such as impaired lung compliance and atelectasis of the isolated perfused lung, were also found to cause changes in respiratory parameters, some of which would be severe enough to lead to death in in vivo tests with rats. The changes in respiratory parameters suggest that the mode-of-action is associated with impairment of the surfactant layer. Therefore, pre-testing in the isolated perfused rat lung allows the identification of surface-active substances with the potential for causing acute inhalation toxicity. PMID:23067301

  14. Meeting the oxygen requirements of an isolated perfused rat liver

    E-print Network

    Izamis, Maria-Louisa, 1979-

    2006-01-01

    Liver perfusion systems can be used as organ culture platforms for metabolic, genetic and systems engineering, tissue regeneration, pharmacokinetics, organ storage and marginal donor reconditioning for transplantation. The ...

  15. New imaging technology: measurement of myocardial perfusion by contrast echocardiography

    NASA Technical Reports Server (NTRS)

    Rubin, D. N.; Thomas, J. D.

    2000-01-01

    Myocardial perfusion imaging has long been a goal for the non-invasive echocardiographic assessment of the heart. However, many factors at play in perfusion imaging have made this goal elusive. Harmonic imaging and triggered imaging with newer contrast agents have made myocardial perfusion imaging potentially practical in the very near future. The application of indicator dilution theory to the coronary circulation and bubble contrast agents is fraught with complexities and sources of error. Therefore, quantification of myocardial perfusion by non-invasive echocardiographic imaging requires further investigation in order to make this technique clinically viable.

  16. Radionuclide Tracers for Myocardial Perfusion Imaging and Blood Flow Quantification.

    PubMed

    deKemp, Robert A; Renaud, Jennifer M; Klein, Ran; Beanlands, Rob S B

    2016-02-01

    Myocardial perfusion imaging is performed most commonly using Tc-99m-sestamibi or tetrofosmin SPECT as well as Rb-82-rubidium or N-13-ammonia PET. Diseased-to-normal tissue contrast is determined by the tracer retention fraction, which decreases nonlinearly with flow. Reduced tissue perfusion results in reduced tracer retention, but the severity of perfusion defects is typically underestimated by 20% to 40%. Compared to SPECT, retention of the PET tracers is more linearly related to flow, and therefore, the perfusion defects are measured more accurately using N-13-ammonia or Rb-82. PMID:26590778

  17. Spontaneous breathing with airway pressure release ventilation favors ventilation in dependent lung regions and counters cyclic alveolar collapse in oleic-acid-induced lung injury: a randomized controlled computed tomography trial

    PubMed Central

    Wrigge, Hermann; Zinserling, Jörg; Neumann, Peter; Muders, Thomas; Magnusson, Anders; Putensen, Christian; Hedenstierna, Göran

    2005-01-01

    Introduction Experimental and clinical studies have shown a reduction in intrapulmonary shunt with spontaneous breathing during airway pressure release ventilation (APRV) in acute lung injury. This reduction was related to reduced atelectasis and increased aeration. We hypothesized that spontaneous breathing will result in better ventilation and aeration of dependent lung areas and in less cyclic collapse during the tidal breath. Methods In this randomized controlled experimental trial, 22 pigs with oleic-acid-induced lung injury were randomly assigned to receive APRV with or without spontaneous breathing at comparable airway pressures. Four hours after randomization, dynamic computed tomography scans of the lung were obtained in an apical slice and in a juxtadiaphragmatic transverse slice. Analyses of regional attenuation were performed separately in nondependent and dependent halves of the lungs on end-expiratory scans and end-inspiratory scans. Tidal changes were assessed as differences between inspiration and expiration of the mechanical breaths. Results Whereas no differences were observed in the apical slices, spontaneous breathing resulted in improved tidal ventilation of dependent lung regions (P < 0.05) and less cyclic collapse (P < 0.05) in the juxtadiaphragmatic slices. In addition, with spontaneous breathing, the end-expiratory aeration increased and nonaerated tissue decreased in dependent lung regions close to the diaphragm (P < 0.05 for the interaction ventilator mode and lung region). Conclusion Spontaneous breathing during APRV redistributes ventilation and aeration to dependent, usually well-perfused, lung regions close to the diaphragm, and may thereby contribute to improved arterial oxygenation. Spontaneous breathing also counters cyclic collapse, which is a risk factor for ventilation-associated lung injury. PMID:16356227

  18. Mechanical ventilation: introduction for the pharmacy practitioner.

    PubMed

    Cawley, Michael J

    2011-02-01

    Mechanical ventilation is a common therapeutic modality required for the management of patients unable to maintain adequate intrinsic ventilation and oxygenation. Mechanical ventilators can be found within various hospital and nonhospital environments (ie, nursing homes, skilled nursing facilities, and patient's home residence), but these devices generally require the skill of a multidisciplinary health care team to optimize therapeutic outcomes. Unfortunately, pharmacists have been excluded in the discussion of mechanical ventilation since this therapeutic modality may be perceived as irrelevant to drug utilization and the usual scope of practice of a hospital pharmacist. However, the pharmacist provides a crucial role as a member of the multidisciplinary team in the management of the mechanically ventilated patient by verifying accuracy of prescribed medications, providing recommendations of alternative drug selections, monitoring for drug and disease interactions, assisting in the development of institutional weaning protocols, and providing quality assessment of drug utilization. Pharmacists may be intimidated by the introduction of advanced ventilator microprocessor technology, but understanding and integrating ventilator management with the pharmacotherapeutic needs of the patient will ultimately help the pharmacist be a better qualified and respected practitioner. The goal of this article is to assist the pharmacy practitioner with a better understanding of mechanical ventilation and to apply this information to improve delivery of pharmaceutical care. PMID:21507870

  19. 29 CFR 1910.94 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Ventilation. 1910.94 Section 1910.94 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Occupational Health and Environmental Control § 1910.94 Ventilation. (a) Abrasive blasting—(1)...

  20. 46 CFR 72.05-50 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Ventilation. 72.05-50 Section 72.05-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 72.05-50 Ventilation. (a) Where the term duct is used in this section, it shall include trunks, plenums, and any other...

  1. Commissioning Ventilated Containment Systems in the Laboratory

    SciTech Connect

    Not Available

    2008-08-01

    This Best Practices Guide focuses on the specialized approaches required for ventilated containment systems, understood to be all components that drive and control ventilated enclosures and local exhaust systems within the laboratory. Geared toward architects, engineers, and facility managers, this guide provides information about technologies and practices to use in designing, constructing, and operating operating safe, sustainable, high-performance laboratories.

  2. Infiltration in ASHRAE's Residential Ventilation Standards

    SciTech Connect

    Sherman, Max

    2008-10-01

    The purpose of ventilation is to dilute or remove indoor contaminants that an occupant could be exposed to. It can be provided by mechanical or natural means. ASHRAE Standards including standards 62, 119, and 136 have all considered the contribution of infiltration in various ways, using methods and data from 20 years ago. The vast majority of homes in the United States and indeed the world are ventilated through natural means such as infiltration caused by air leakage. Newer homes in the western world are tight and require mechanical ventilation. As we seek to provide acceptable indoor air quality at minimum energy cost, it is important to neither over-ventilate norunder-ventilate. Thus, it becomes critically important to correctly evaluate the contribution infiltration makes to both energy consumption and equivalent ventilation. ASHRAE Standard 62.2 specifies how much mechanical ventilation is considered necessary to provide acceptable indoor air quality, but that standard is weak on how infiltration can contribute towards meeting the total requirement. In the past ASHRAE Standard 136 was used to do this, but new theoretical approaches and expanded weather data have made that standard out of date. This article will describe how to properly treat infiltration as an equivalent ventilation approach and then use new data and these new approaches to demonstrate how these calculations might be done both in general and to update Standard 136.

  3. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  4. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  5. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  6. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  7. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  8. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory § 194.15-5 Ventilation. (a) Operations, reactions...

  9. Preoperational test report, primary ventilation system

    SciTech Connect

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Primary Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space filtered venting of tanks AY101, AY102, AZ101, AZ102. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  10. Mnesic imbalance: a cognitive theory about autism spectrum disorders

    PubMed Central

    Romero-Munguía, Miguel Ángel

    2008-01-01

    Autism is characterized by impairments in social interaction, communicative capacity and behavioral flexibility. Some cognitive theories can be useful for finding a relationship between these irregularities and the biological mechanisms that may give rise to this disorder. Among such theories are mentalizing deficit, weak central coherence and executive dysfunction, but none of them has been able to explain all three diagnostic symptoms of autism. These cognitive disorders may be related among themselves by faulty learning, since several research studies have shown that the brains of autistic individuals have abnormalities in the cerebellum, which plays a role in procedural learning. In keeping with this view, one may postulate the possibility that declarative memory replaces faulty procedural memory in some of its functions, which implies making conscious efforts in order to perform actions that are normally automatic. This may disturb cognitive development, resulting in autism symptoms. Furthermore, this mnesic imbalance is probably involved in all autism spectrum disorders. In the present work, this theory is expounded, including preliminary supporting evidence. PMID:18925971

  11. Biomedical Implications of Heavy Metals Induced Imbalances in Redox Systems

    PubMed Central

    Singh, Shweta; Siddiqi, Nikhat J.

    2014-01-01

    Several workers have extensively worked out the metal induced toxicity and have reported the toxic and carcinogenic effects of metals in human and animals. It is well known that these metals play a crucial role in facilitating normal biological functions of cells as well. One of the major mechanisms associated with heavy metal toxicity has been attributed to generation of reactive oxygen and nitrogen species, which develops imbalance between the prooxidant elements and the antioxidants (reducing elements) in the body. In this process, a shift to the former is termed as oxidative stress. The oxidative stress mediated toxicity of heavy metals involves damage primarily to liver (hepatotoxicity), central nervous system (neurotoxicity), DNA (genotoxicity), and kidney (nephrotoxicity) in animals and humans. Heavy metals are reported to impact signaling cascade and associated factors leading to apoptosis. The present review illustrates an account of the current knowledge about the effects of heavy metals (mainly arsenic, lead, mercury, and cadmium) induced oxidative stress as well as the possible remedies of metal(s) toxicity through natural/synthetic antioxidants, which may render their effects by reducing the concentration of toxic metal(s). This paper primarily concerns the clinicopathological and biomedical implications of heavy metals induced oxidative stress and their toxicity management in mammals. PMID:25184144

  12. Dynamic Behaviour of Ventilated Hydrofoils.

    NASA Astrophysics Data System (ADS)

    Kjeldsen, Morten; Arndt, Roger; Wosnik, Martin

    2006-11-01

    In certain types of pumping applications oscillations are induced by operation with liquids containing a free gas load. In order to understand the physics of this process, a series of tests with a ventilated A 2D NACA 0015 hydrofoil were performed in the water tunnel at the St. Anthony Falls Laboratory of the University of Minnesota. The special bubble removal feature of the water tunnel allowed continuous ventilation without experiencing visible bubbles upstream the hydrofoil. These studies build on previous work on cavitation-induced oscillations. Gas injection studies were made over a range of gas flow rates and test section pressure. The results clearly show that lift oscillations increase in intensity when the gas load is increased. The point of maximum unsteadiness is also associated the rapid decline of the foil performance as measured as average lift. Further increase of the gas injection load gives a steady behaviour with almost no lift. These experiments are compared with traditional cavitation experiments. The similarities between gas injection- and cavitation induced unsteadiness on the hydrofoil are many, but the amplitude of lift oscillations found on the foil with gas injection corresponds to about 50% of that found for cavitating hydrofoils. The fact that the oscillations are periodic leads to the consideration of both passive and active control.

  13. Protocol: Whole Brain Mouse Perfusion, PCASL-EPI, Page 1 of 2 Author: R.Bussell 3/16/2012 Protocol: Whole Brain Mouse Perfusion,

    E-print Network

    California at San Diego, University of

    Protocol: Whole Brain Mouse Perfusion, PCASL-EPI, Page 1 of 2 Author: R.Bussell 3/16/2012 Protocol: Whole Brain Mouse Perfusion, PCASL-EPI Purpose Measurement of whole brain perfusion in a mouse. Protocol Directory: "C_ MouseWholeBrainPerfusion" Type Protocol Name In-plane resolution, slice thickness Slices Scan

  14. Computational Study of Effects of Tension Imbalance on Phonation in a Three Dimensional Tubular Larynx Model

    PubMed Central

    Xue, Qian; Zheng, Xudong; Mittal, Rajat; Bielamowicz, Steve

    2014-01-01

    Summary Objective The current study explores the use of a continuum based computational model to investigate the effect of left right tension imbalance on vocal fold vibrations and glottal aerodynamics, as well as its implication on phonation. The study allows us to gain new insights into the underlying physical mechanism of irregularities induced by vocal fold tension imbalance associated with unilateral cricothyroid muscle paralysis. Method A three dimensional simulation of glottal flow and vocal fold dynamics in a tubular laryngeal model with tension imbalance was conducted by using a coupled flow-structure interaction computational model. Tension imbalance was modeled by reducing by 20% the Young’s modulus of one of the vocal folds, while holding vocal fold length constant. Effects of tension imbalance on vibratory characteristic of the vocal folds and on the time-varying properties of glottal airflow as well as the aerodynamic energy transfer are comprehensively analyzed. Results and Conclusions The analysis demonstrates that the continuum based biomechanical model can provide a good description of phonatory dynamics in tension imbalance conditions. It is found that while 20% tension imbalance does not have noticeable effects on the fundamental frequency, it does lead to a larger glottal flow leakage and asymmetric vibrations of the two vocal folds. A detailed analysis of the energy transfer suggests that the majority of the energy is consumed by the lateral motion of the vocal folds and the net energy transferred to the softer fold is less than the one transferred to the normal fold. PMID:24725589

  15. An intelligent control system for ventilators.

    PubMed

    Wang, C S; Shaw, D; Jih, K S

    1998-10-01

    This study reports on a ventilator system that consists of several intelligent modules for controlling ventilator operation. These modules are software programs in two controllers. One controller is a personal computer used for diagnoses, determining settings and checking the effects of settings. The other controller is a single-chip microprocessor in a ventilator that controls the ventilator's settings in accordance with the computer settings. After setting up the system, an artificial lung model simulating a patient's lung is used to test the system. The result of test run indicated that it always responds to a patient's lung condition in a stable manner. Thus, the proposed system with its intelligent modules may assist clinicians in caring for patients and managing ventilator operation. PMID:9832029

  16. Mine ventilation and air conditioning. 3. edition

    SciTech Connect

    Hartman, H.L.; Mutmansky, J.M.; Ramani, R.V.; Wang, Y.J.

    1998-12-31

    This revised edition presents an engineering design approach to ventilation and air conditioning as part of the comprehensive environmental control of the mine atmosphere. It provides an in-depth look, for practitioners who design and operate mines, into the health and safety aspects of environmental conditions in the underground workplace. The contents include: Environmental control of the mine atmosphere; Properties and behavior of air; Mine air-quality control; Mine gases; Dusts and other mine aerosols; Mine ventilation; Airflow through mine openings and ducts; Mine ventilation circuits and networks; Natural ventilation; Fan application to mines; Auxiliary ventilation and controlled recirculation; Economics of airflow; Control of mine fires and explosions; Mine air conditioning; Heat sources and effect in mines; Mine air conditioning systems; Appendices; References; Answers to selected problems; and Index.

  17. Neonatal mechanical ventilation: Indications and outcome

    PubMed Central

    Iqbal, Qazi; Younus, Mir M.; Ahmed, Asif; Ahmad, Ikhlas; Iqbal, Javed; Charoo, Bashir A.; Ali, S Wajid

    2015-01-01

    Background and Aims: Decreasing mortality in sick and ventilated neonates is an endeavor of all neonatologists. To reduce the high mortality in this group of neonates, identification of risk factors is important. This study was undertaken to find out the indications of ventilation and complications in ventilated neonates and also study possible predictors of outcome. Subjects: Age <1-month; mechanically ventilated; not having suspected metabolic disorders or congenital anomalies; excluding postoperative patients. Methods: Neonates consecutively put on mechanical ventilation during the study period (October 2011 to November 2013) enrolled. Primary disease of the neonates along with complications present listed. Clinical and laboratory parameters analyzed to find the predictors of mortality. Results: Total 300 neonates were ventilated. 52% were male. Mean age, weight, and gestational age were 21 ± 62 h, 2320 ± 846.2 g, and 35.2 ± 4.9 weeks, respectively. 130 (43%) neonates died. Respiratory distress syndrome (RDS) (31.1%), sepsis (22.7%), and birth asphyxia (18%) were the most common indications for ventilation. Mortality in ventilated patients with sepsis, pneumonia, RDS or birth asphyxia was 64.7%, 60%, 44.6%, and 33.3%, respectively. Weight <2500 g, gestation <34 weeks, initial pH <7.1, presence of sepsis, apnea, shock, pulmonary hemorrhage, hypoglycemia, neutropenia, and thrombocytopenia were significantly associated with mortality (P < 0.05). Resuscitation at birth, seizures, intra ventricular hemorrhage, pneumothorax, ventilator-associated pneumonia, PO2, or PCO2 did not have a significant association with mortality. On logistic regression, gestation <34 weeks, initial pH <7.1, pulmonary hemorrhage, or shock were independently significant predictors of mortality. Conclusions: Weight <2500 g, gestation <34 weeks, initial arterial pH <7.1, shock, pulmonary hemorrhage, apnea, hypoglycemia, neutropenia, and thrombocytopenia were significant predictors of mortality in ventilated neonates. PMID:26430338

  18. A new system for understanding modes of mechanical ventilation.

    PubMed

    Chatburn, R L; Primiano, F P

    2001-06-01

    Numerous ventilation modes and ventilation options have become available as new mechanical ventilators have reached the market. Ventilator manufacturers have no standardized terminology for ventilator modes and ventilation options, and ventilator operator's manuals do not help the clinician compare the modes of ventilators from different manufacturers. This article proposes a standardized system for classifying ventilation modes, based on general engineering principles and a small set of explicit definitions. Though there may be resistance by ventilator manufacturers to a standardized system of ventilation terminology, clinicians and health care equipment purchasers should adopt such a system in the interest of clear communication--the lack of which prevents clinicians from fully understanding the therapies they administer and could compromise the quality of patient care. PMID:11353550

  19. [Myocardial perfusion imaging by digital subtraction angiography].

    PubMed

    Kadowaki, H; Ishikawa, K; Ogai, T; Katori, R

    1986-03-01

    Several methods of digital subtraction angiography (DSA) were compared to determine which could better visualize regional myocardial perfusion using coronary angiography in seven patients with myocardial infarction, two with angina pectoris and five with normal coronary arteries. Satisfactory DSA was judged to be achieved if the shape of the heart on the mask film was identical to that on the live film and if both films were exactly superimposed. To obtain an identical mask film in the shape of each live film, both films were selected from the following three phases of the cardiac cycle; at the R wave of the electrocardiogram, 100 msec before the R wave, and 200 msec before the R wave. The last two were superior for obtaining mask and live films which were similar in shape, because the cardiac motion in these phases was relatively small. Using these mask and live films, DSA was performed either with the continuous image mode (CI mode) or the time interval difference mode (TID mode). The overall perfusion of contrast medium through the artery to the vein was adequately visualized using the CI mode. Passage of contrast medium through the artery, capillary and vein was visualized at each phase using TID mode. Subtracted images were displayed and photographed, and the density of the contrast medium was adequate to display contour lines as in a relief map. Using this DSA, it was found that regional perfusion of the contrast medium was not always uniform in normal subjects, depending on the typography of the coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3537156

  20. Pseudoketogenesis in the perfused rat heart

    SciTech Connect

    Fink, G.; Desrochers, S.; Des Rosiers, C.; Garneau, M.; David, F.; Daloze, T.; Landau, B.R.; Brunengraber, H.

    1988-12-05

    Ketogenesis is usually measured in vivo by dilution of tracers of (3R)-hydroxybutyrate or acetoacetate. We show that, in perfused working rat hearts, the specific activities of (3R)-hydroxybutyrate and acetoacetate are diluted by isotopic exchanges in the absence of net ketogenesis. We call this process pseudoketogenesis. When hearts are perfused with buffer containing 2.3 mM of (4-3H)- plus (3-14C)acetoacetate, the specific activities of (4-3H) and (3-14C)acetoacetate decrease while C-1 of acetoacetate becomes progressively labeled with 14C. This is explained by the reversibility of reactions catalyzed by mitochondrial 3-oxoacid-CoA transferase and acetoacetyl-CoA thiolase. After activation of labeled acetoacetate, the specific activity of acetoacetyl-CoA is diluted by unlabeled acetoacetyl-CoA derived from endogenous fatty acids or glucose. Acetoacetyl-CoA thiolase partially exchanges 14C between C-1 and C-3 of acetoacetyl-CoA. Finally, 3-oxoacid-CoA transferase liberates weakly labeled acetoacetate which dilutes the specific activity of extracellular acetoacetate. An isotopic exchange in the reverse direction is observed when hearts are perfused with unlabeled acetoacetate plus (1-14C)-, (13-14C)-, or (15-14C)palmitate; here also, acetoacetate becomes labeled on C-1 and C-3. Computations of specific activities of (3R)-hydroxybutyrate, acetoacetate, and acetyl-CoA yield minimal rates of pseudoketogenesis ranging from 19 to 32% of the net uptake of (3R)-hydroxybutyrate plus acetoacetate by the heart.

  1. Preserving low perfusion during surgical liver blood inflow control prevents hepatic microcirculatory dysfunction and irreversible hepatocyte injury in rats

    PubMed Central

    Li, Chong-Hui; Chen, Yong-Wei; Chen, Yong-Liang; Yao, Li-Bin; Ge, Xin-Lan; Pan, Ke; Zhang, Ai-Qun; Dong, Jia-Hong

    2015-01-01

    Hepatic ischaemia/reperfusion (I/R) injury is of primary concern during liver surgery. We propose a new approach for preserving low liver blood perfusion during hepatectomy either by occlusion of the portal vein (OPV) while preserving hepatic artery flow or occlusion of the hepatic artery while limiting portal vein (LPV) flow to reduce I/R injury. The effects of this approach on liver I/R injury were investigated. Rats were randomly assigned into 4 groups: sham operation, occlusion of the portal triad (OPT), OPV and LPV. The 7-day survival rate was significantly improved in the OPV and LPV groups compared with the OPT group. Microcirculatory liver blood flow recovered rapidly after reperfusion in the OPV and LPV groups but decreased further in the OPT group. The OPV and LPV groups also showed much lower ALT and AST levels, Suzuki scores, inflammatory gene expression levels, and parenchymal necrosis compared with the OPT group. An imbalance between the expression of vasoconstriction and vasodilation genes was observed in the OPT group but not in the OPV or LPV group. Therefore, preserving low liver blood perfusion by either the OPV or LPV methods during liver surgery is very effective for preventing hepatic microcirculatory dysfunction and hepatocyte injury. PMID:26400669

  2. HVAC (heating, ventilation, air conditioning) literature in Japan: A critical review

    SciTech Connect

    Hane, G.J.

    1988-02-01

    Japanese businessmen in the heating, ventilation, air conditioning, and refrigeration (HVACandR) industry consider the monitoring of technical and market developments in the United States to be a normal part of their business. In contrast, efforts by US businessmen to monitor Japanese HVAC and R developments are poorly developed. To begin to redress this imbalance, this report establishes the groundwork for a more effective system for use in monitoring Japanese HVAC and R literature. Discussions of a review of the principal HVAC and R publications in Japan and descriptions of the type of information contained in each of those publications are included in this report. Since the Japanese HVAC and R literature is abundant, this report also provides practical suggestions on how a researcher or research manager can limit the monitoring effort to the publications and type of information that would most likely be of greatest value.

  3. Isolated Lung Perfusion for Pulmonary Metastases.

    PubMed

    Ward, Alison; Prokrym, Kirill; Pass, Harvey

    2016-02-01

    Isolated lung perfusion (ILP) is a surgical technique developed to treat pulmonary metastases. During ILP, high-dose chemotherapy is delivered into the pulmonary vasculature, minimizing systemic exposure and delivering the chemotherapeutic agent directly to the lung. ILP has been studied extensively in a variety of animal models and in humans in phase I trials. The most frequently studied chemotherapeutic agents used in ILP are doxorubicin, 5-flurodeoxyuridine, tumor necrosis factor-?, paclitaxel, melphalan, gemcitabine, and cisplatin. Phase I clinical trials with ILP have shown that ILP can be safely performed in humans but with mixed clinical results and poor long-term survival. PMID:26611511

  4. Analysis of the method for ventilation heterogeneity assessment using the Otis model and forced oscillations.

    PubMed

    Glapi?ski, Jaros?aw; Mroczka, Janusz; Polak, Adam G

    2015-12-01

    Increased heterogeneity of the lung disturbs pulmonary gas exchange. During bronchoconstriction, inflammation of lung parenchyma or acute respiratory distress syndrome, inhomogeneous lung ventilation can become bimodal and increase the risk of ventilator-induced lung injury during mechanical ventilation. A simple index sensitive to ventilation heterogeneity would be very useful in clinical practice. In the case of bimodal ventilation, the index (H) can be defined as the ratio between the longer and shorter time constant characterising regions of contrary mechanical properties. These time constants can be derived from the Otis model fitted to input impedance (Zin) measured using forced oscillations. In this paper we systematically investigated properties of the aforementioned approach. The research included both numerical simulations and real experiments with a dual-lung simulator. Firstly, a computational model mimicking the physical simulator was derived and then used as a forward model to generate synthetic flow and pressure signals. These data were used to calculate the input impedance and then the Otis inverse model was fitted to Zin by means of the Levenberg-Marquardt (LM) algorithm. Finally, the obtained estimates of model parameters were used to compute H. The analysis of the above procedure was performed in the frame of Monte Carlo simulations. For each selected value of H, forward simulations with randomly chosen lung parameters were repeated 1000 times. Resulting signals were superimposed by additive Gaussian noise. The estimated values of H properly indicated the increasing level of simulated inhomogeneity, however with underestimation and variation increasing with H. The main factor responsible for the growing estimation bias was the fixed starting vector required by the LM algorithm. Introduction of a correction formula perfectly reduced this systematic error. The experimental results with the dual-lung simulator confirmed potential of the proposed procedure to properly deduce the lung heterogeneity level. We conclude that the heterogeneity index H can be used to assess bimodal ventilation imbalances in cases when this phenomenon dominates lung properties, however future analyses, including the impact of lung tissue viscoelasticity and distributed airway or tissue inhomogeneity on H estimates, as well as studies in the time domain, are advisable. PMID:26363677

  5. Chromosomal imbalances of primary and metastatic lung adenocarcinomas.

    PubMed

    Goeze, Almut; Schlüns, Karsten; Wolf, Guenter; Thäsler, Zsuzsanna; Petersen, Simone; Petersen, Iver

    2002-01-01

    Comparative genomic hybridization (CGH) was used to screen 83 lung adenocarcinomas of 60 patients for chromosomal imbalances. The most common alteration was DNA overrepresentation on chromosome 1q, with a peak incidence at 1q22-q23 in 73% of the primary tumours, followed by DNA overrepresentation on chromosomes 8q and 20q, and deletions on chromosomes 3p, 4q, 6q, 9p, 9q, and 13q, in at least 60%. The generation of a difference histogram of metastasizing versus non-metastasizing tumours and a case-by-case histogram for the comparison of 23 paired samples of primary tumours and corresponding metastases suggested that deletions on chromosomes 3p12-p14, 3p22-p24, 4p13-15.1, 4q21-qter, 6q21-qter, 8p, 10q, 14q21, 17p12-p13, 20p12, and 21q, and overrepresentations on chromosomes 1q21-q25, 7q11.2, 9q34, 11q12-q13, 14q11-q13, and 17q25 are associated with the metastatic phenotype. In contrast, losses on chromosome 19 and gains on 3p, 4q, 5p, and 6q were preferentially found in non-metastasizing tumours. The analysis of the paired samples revealed considerable chromosomal instability, but indicated a clonal relationship in each case. The primary tumours often showed additional deletions, suggesting that loss of function mutations are critical in the initial phase of tumour dissemination, whereas the metastases preferentially acquired DNA gains, probably modulating the metastatic phenotype. The primary data from this study (ratio profiles, clinicopathological parameters, histograms) are also available at http://amba.charite.de/cgh. PMID:11748636

  6. Influence of lipid imbalance on butyrylcholinesterase activity and biotransformation efficiency.

    PubMed

    Sisková, K; Bilka, F; Adameová, A; Balazová, A; Mydla, M; Pauliková, I

    2012-04-01

    Butyrylcholinesterase (EC 3.1.1.8, BChE) is highly active in plasma, skin and lung, the tissues that first contact xenobiotics, supporting a role for BChE in detoxication of xenobiotics including medicaments. A possible involvement of BChE in lipid metabolism has been suggested. Elevated BChE activity in obese individuals correlates with some parameters of lipid metabolism including increased levels of triacylglycerols (TAG) and cholesterol. The aim of this study was to estimate the BChE activity in rats on subcellular and inter-organ levels under the conditions of untreated and treated primary hypertriacylglycerolemia with the TAG lowering agent fenofibrate. No changes in BChE activity were observed in obese animals. However fenofibrate administration led to significant increase of BChE activity in all examined tissues (plasma, liver, white adipose tissue). The impact of lipid metabolic imbalance on BChE biotransformation ability was tested by measuring the rate of hydrolysis of 0,1 to 8 mM concentrations of the antimicrobial agent N-(2-benzoyloxyethyl)-ethyldimethylammonium bromide (BCH2). The results revealed a complete shift in the BChE kinetics in all studied models. In animals with hypertriacylglycerolemia the Km value of liver BChE rised 4,6-fold, but the total enzyme efficiency expressed as Vmax/Km dropped 40% comparing to control. In contrast, in animals treated with fenofibrate the BChE efficiency increased in liver 1,6-fold. We conclude here that BChE detoxification capacity is essentially altered under conditions of disturbed lipid metabolism. Clinically, this knowledge could be important in a view of xenobiotic elimination, especially when routinely prescribed medicaments are concerned. PMID:22570941

  7. Magnetic Resonance Perfusion Imaging in the Study of Language

    ERIC Educational Resources Information Center

    Hillis, Argye E.

    2007-01-01

    This paper provides a brief review of various uses of magnetic resonance perfusion imaging in the investigation of brain/language relationships. The reviewed studies illustrate how perfusion imaging can reveal areas of brain where dysfunction due to low blood flow is associated with specific language deficits, and where restoration of blood flow…

  8. Microfluidic Perfusion for Regulating Diffusible Signaling in Stem Cells

    E-print Network

    Voldman, Joel

    Microfluidic Perfusion for Regulating Diffusible Signaling in Stem Cells Katarina Blagovic1 , Lily and in vitro, and are particularly important in embryonic stem cell (ESC) pluripotency and lineage commitment, Voldman J (2011) Microfluidic Perfusion for Regulating Diffusible Signaling in Stem Cells. PLoS ONE 6

  9. Registration and Analysis of Myocardial Perfusion Magnetic Resonance Images

    E-print Network

    on the presented methods. Data from 10 patients with acute myocardial infarction is provided for this pur- poseRegistration and Analysis of Myocardial Perfusion Magnetic Resonance Images Hildur ´Olafsd This thesis presents the registration and analysis of myocardial perfusion mag- netic resonance images

  10. [Recommendations for invasive home mechanical ventilation].

    PubMed

    Randerath, W J; Kamps, N; Brambring, J; Gerhard, F; Lorenz, J; Rudolf, F; Rosseau, S; Scheumann, A; Vollmer, V; Windisch, W

    2011-02-01

    Due to chronic respiratory failure, a proportion of patients require long-term home ventilation therapy. The treating doctors, nurses and therapists, as well as employees of the health insurance provider, all require specialized knowledge in order to establish and monitor home ventilation. The following document represents a consensus formed by the participating specialist societies, the health insurers and their medical advisory services. The recommendations for accomplishing home mechanical ventilation are based on the "S2 Guidelines for Non-Invasive and Invasive Mechanical Ventilation for Treatment of Chronic Respiratory Failure", and provide advice about the necessary qualifications of medical and nursing practitioners working in specialised ventilation centres or in the home setting. Management of transfer, which comprises the medical, technical and organisational requirements for releasing the patient from hospital care, is of paramount importance. In outpatient care, the requirements for the recruitment of resources, monitoring of procedures, adjustment of ventilation, and frequency of check-ups are each addressed. The recommendations are supplemented by appendices which include patient transfer forms, checklists for the supply of basic resources for home ventilation, as well as a template for the letter of discharge from hospital. PMID:21294061

  11. Evidence-based ventilator weaning and discontinuation.

    PubMed

    MacIntyre, Neil R

    2004-07-01

    Ventilator management of a patient who is recovering from acute respiratory failure must balance competing objectives. Discontinuing mechanical ventilation and removing the artificial airway as soon as possible reduces the risk of ventilator-induced lung injury, nosocomial pneumonia, airway trauma from the endotracheal tube, and unnecessary sedation, but premature ventilator-discontinuation or extubation can cause ventilatory muscle fatigue, gas exchange failure, and loss of airway protection. In 1999 the McMaster University Outcomes Research Unit conducted a comprehensive evidence-based review of the literature on ventilator-discontinuation. Using that literature review, the American College of Chest Physicians, the Society of Critical Care Medicine, and the American Association for Respiratory Care created evidence-based guidelines, which include the following principles: 1. Frequent assessment is required to determine whether ventilatory support and the artificial airway are still needed. 2. Patients who continue to require support should be continually re-evaluated to assure that all factors contributing to ventilator dependence are addressed. 3. With patients who continue to require support, the support strategy should maximize patient comfort and provide muscle unloading. 4. Patients who require prolonged ventilatory support beyond the intensive care unit should go to specialized facilities that can provide more gradual support reduction strategies. 5. Ventilator-discontinuation and weaning protocols can be effectively carried out by nonphysician clinicians. PMID:15222913

  12. Optimization on Emergency Longitudinal Ventilation Design

    NASA Astrophysics Data System (ADS)

    Se, Camby M. K.; Yuen, Richard K. K.; Cheung, Sherman C. P.; Tu, Jiyuan

    2010-05-01

    Emergency ventilation design in longitudinally ventilated vehicular tunnels is vital to provide safe egress route for tunnel user under fire situations. In this study, the influences of the location of active fan groups on the upstream velocity are investigated using Computational Fluid Dynamics (CFD) techniques. The numeric model was firstly validated again the experimental data from Memorial Tunnel Fire Ventilation Test Program (MTFVTP). Based on the validated model, parametric studies were then preformed attempting to establish a semi-empirical correlation between the location of fan groups and the upstream velocity. In the presence of solid fire, it was found that the buoyant force by the fire source and inertial force by the fans interact with each other and resulted in a "leveling-off" characteristic when the inertial force is no longer dominating. Such interaction re-distributed the ventilation flow direction and sequentially reduces the magnitude of the upstream velocity. In other word, the industrial practice of activating furthest fan group may not be able to prevent the backlayering as a consequence of solid fires. Fans closer to the fire source are recommended to be activated for preventing the hazard of backlayering. Furthermore, through the parametric study, location of ventilation fans is found to have significant effect on the upstream velocity. Such finding suggests that other geometrical parameters could also impose adverse effects to the ventilation system. Existing empirical equation could be insufficient to cover all possible ventilation design scenarios.

  13. Quantification of ventilation characteristics of a helmet.

    PubMed

    Van Brecht, A; Nuyttens, D; Aerts, J M; Quanten, S; De Bruyne, G; Berckmans, D

    2008-05-01

    Despite the augmented safety offered by wearing a cyclist crash helmet, many cyclists still refuse to wear one because of the thermal discomfort that comes along with wearing it. In this paper, a method is described that quantifies the ventilation characteristics of a helmet using tracer gas experiments. A Data-Based Mechanistic model was applied to provide a physically meaningful description of the dominant internal dynamics of mass transfer in the imperfectly mixed fluid under the helmet. By using a physical mass balance, the local ventilation efficiency could be described by using a single input-single output system. Using this approach, ventilation efficiency ranging from 0.06 volume refreshments per second (s(-1)) at the side of the helmet to 0.22s(-1) at the rear ventilation opening were found on the investigated helmet. The zones at the side were poorly ventilated. The influence of the angle of inclination on ventilation efficiency was dependent on the position between head and helmet. General comfort of the helmet can be improved by increasing the ventilation efficiency of fresh air at the problem zones. PMID:17959135

  14. Weaning from prolonged mechanical ventilation.

    PubMed

    Nevins, M L; Epstein, S K

    2001-03-01

    The development of weaning failure and need for PMV is multifactorial in origin, involving disorders of pulmonary mechanics and complications associated with critical illness. The underlying disease process is clearly important when discussing mechanisms of ventilator dependence; interventions therefore must be tailored to individual patients. Unfortunately, the main conclusion that can be drawn from the sum of the studies investigating patients on PMV to date is that an evidence-based approach to weaning is not possible and more research needs to be done. New studies need to incorporate severity-of-illness scores and an assessment of principal and comorbid conditions to allow for comparison of the findings from different centers. The best approach to a patient requiring PMV after exclusion of easily treatable conditions is not known. The literature regarding both acute and chronic cases suggests that a systematic approach to weaning involving the participation of multiple caregivers, including nurses, physicians, and respiratory, physical, and speech therapists facilitates liberation from MV. Although a gradual decrement in ventilator support would seem prudent, Scheinhorn et al have begun to identify a subpopulation of patients who can tolerate an acceleration of the weaning process. Given the known complications associated with MV, it is crucial that further research be performed to identify patients as soon as they are capable of breathing spontaneously. The literature demonstrates through multiple studies that satisfactory patient outcomes are attainable and can be achieved at LTAC facilities in a more cost-effective manner than in an ICU setting. The trend toward the concentration of patients into specialized regional weaning centers should facilitate the research process and continue to improve outcomes in this population. PMID:11315451

  15. The Role of Anion Exchanger on Pulmonary Vascular Response to Sustained Alveolar Hypoxia in the Isolated Perfused Rabbit Lung

    PubMed Central

    Ketabchi, Farzaneh; Mansoori, Somayeh; Moosavi, Seyed Mostafa Shid

    2015-01-01

    Background Some respiratory diseases may induce alveolar hypoxia thereby hypoxic pulmonary vasoconstriction (HPV). However, the mechanisms of this physiologic phenomenon are not fully understood. This study was the first to investigate the role of anion exchanger in sustained HPV. Methods Experiments were performed in the isolated perfused rabbit lung. After preparation, the lungs were divided into six groups: two DIDS (4,4-diisothiocyanostilbene 2,2-disulfonic acid, anion exchanger inhibitor)-treated [200 µM (n=5) or 400 µM (n=3)] hypoxic groups, two HCO3- free hypoxic groups, one control hypoxic group (n=7) and one control normoxic group (n=4). DIDS were added to the perfusate at 10 minutes before starting the experiments. In the HCO3- free groups, HEPES (4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid) were added to the perfusate instead of bicarbonate. Furthermore, in the HEPES1 (n=4) and HEPES2 (n=4) groups, the lungs were ventilated with hypoxic gas with or without CO2, respectively. Results Ventilation of the lungs with hypoxic gas resulted in biphasic HPV, the acute (0-20 minutes) and sustained (20-60 minutes) phases. No alteration in both phases of HPV was detected by DIDS (200 µM). However, DIDS (400 µM), extended the ascending part of acute HPV until min 24. Both phases of HPV were decreased in the HEPES1 group. However, in the HEPES 2 group, HPV tended to increase during the rising part of the acute phase of HPV. Conclusions Since DIDS (400 µM) extended acute phase of HPV, and HCO3- free perfusate buffer enhanced rising phase of it, therefore it can be suggested that anion exchanger may modulate HPV especially during the acute phase. The abstract of this article was presented as a poster in the congress of European Respiratory Society (ERS) on Monday, 08 September 2014, Munich, Germany and was published in the ERJ September 1, 2014 vol. 44 no. Suppl 58 P2343. PMID:25999626

  16. A Study of Load Imbalance for Parallel Reservoir Simulation with Multiple Partitioning Strategies 

    E-print Network

    Guo, Xuyang

    2015-07-27

    High performance computing is an option to increase reservoir simulation efficiency. However, highly scalable and efficient parallel application is not always easy to obtain from case to case. Load imbalance caused by mesh ...

  17. On the consequences of the energy imbalance for calculating surface conductance to water vapour

    PubMed Central

    Wohlfahrt, Georg; Haslwanter, Alois; Hörtnagl, Lukas; Jasoni, Richard L.; Fenstermaker, Lynn F.; Arnone, John A.; Hammerle, Albin

    2014-01-01

    The Penman-Monteith combination equation, which is most frequently used to derive the surface conductance to water vapour (Gs), implicitly assumes the energy balance to be closed. Any energy imbalance (positive or negative) will thus affect the calculated Gs. Using eddy covariance energy flux data from a temperate grassland and a desert shrub ecosystem we explored five possible approaches of closing the energy imbalance and show that calculated Gs may differ considerably between these five approaches depending on the relative magnitudes of sensible and latent heat fluxes, and the magnitude and sign of the energy imbalance. Based on our limited understanding of the nature of the energy imbalance, we tend to favour an approach which preserves the Bowen-ratio and closes the energy balance on a larger time scale. PMID:24465070

  18. Flux Imbalance Analysis and the Sensitivity of Cellular Growth to Changes in Metabolite Pools

    E-print Network

    Mehta, Pankaj

    intracellular metabolites in the cell. Citation: Reznik E, Mehta P, Segre` D (2013) Flux Imbalance Analysis Reznik1¤ , Pankaj Mehta2,3 , Daniel Segre`1,3,4 * 1 Department of Biomedical Engineering, Boston

  19. SYSTEMIC IMBALANCE OF ESSENTIAL METALS AND CARDIAC GENE EXPRESSION IN RATS FOLLOWING ACUTE PULMONARY ZINC EXPOSURE

    EPA Science Inventory

    We have recently demonstrated that PM containing water-soluble zinc may cause cardiac injury following pulmonary exposure. To investigate if pulmonary zinc exposure causes systemic metal imbalance and direct cardiac effects, we intratracheally (IT) instilled male Wistar Kyoto (WK...

  20. Hepatic perfusion abnormalities during CT angiography: Detection and interpretation

    SciTech Connect

    Freeny, P.C.; Marks, W.M.

    1986-06-01

    Twenty-seven perfusion abnormalities were detected in 17 of 50 patients who underwent computed tomographic angiography (CTA) of the liver. All but one of the perfusion abnormalities occurred in patients with primary or metastatic liver tumors. Perfusion abnormalities were lobar in nine cases, segmental in 11, and subsegmental in seven; 14 were hypoperfusion and 13 were hyperperfusion abnormalities. The causes for the abnormalities included nonperfusion of a replaced hepatic artery (n = 11), cirrhosis and nodular regeneration (n = 3), altered hepatic hemodynamics (e.g., siphoning, laminar flow) caused by tumor (n = 7), contrast media washout from a nonperfused vessel (n = 1), compression of adjacent hepatic parenchyma (n = 1), and unknown (n = 4). Differentiation of perfusion abnormalities from tumor usually can be made by comparing the morphology of the known tumor with the suspected perfusion abnormality, changes of each on delayed CTA scans, and review of initial angiograms and other imaging studies.

  1. The pediatric template of brain perfusion

    PubMed Central

    Avants, Brian B; Duda, Jeffrey T; Kilroy, Emily; Krasileva, Kate; Jann, Kay; Kandel, Benjamin T; Tustison, Nicholas J; Yan, Lirong; Jog, Mayank; Smith, Robert; Wang, Yi; Dapretto, Mirella; Wang, Danny J J

    2015-01-01

    Magnetic resonance imaging (MRI) captures the dynamics of brain development with multiple modalities that quantify both structure and function. These measurements may yield valuable insights into the neural patterns that mark healthy maturation or that identify early risk for psychiatric disorder. The Pediatric Template of Brain Perfusion (PTBP) is a free and public neuroimaging resource that will help accelerate the understanding of childhood brain development as seen through the lens of multiple modality neuroimaging and in relation to cognitive and environmental factors. The PTBP uses cross-sectional and longitudinal MRI to quantify cortex, white matter, resting state functional connectivity and brain perfusion, as measured by Arterial Spin Labeling (ASL), in 120 children 7–18 years of age. We describe the PTBP and show, as a demonstration of validity, that global summary measurements capture the trajectories that demarcate critical turning points in brain maturation. This novel resource will allow a more detailed understanding of the network-level, structural and functional landmarks that are obtained during normal adolescent brain development. PMID:25977810

  2. 46 CFR 38.20-10 - Ventilation-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Ventilation-T/ALL. 38.20-10 Section 38.20-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Venting and Ventilation § 38.20-10 Ventilation—T/ALL. (a) A power ventilation system shall be provided for...

  3. 46 CFR 154.1200 - Mechanical ventilation system: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Mechanical ventilation system: General. 154.1200 Section... Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a... cargo handling equipment must have a fixed, exhaust-type mechanical ventilation system. (b)...

  4. 46 CFR 154.1200 - Mechanical ventilation system: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: General. 154.1200 Section... Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a... cargo handling equipment must have a fixed, exhaust-type mechanical ventilation system. (b)...

  5. 46 CFR 154.1205 - Mechanical ventilation system: Standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: Standards. 154.1205... Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each exhaust type mechanical ventilation system required under § 154.1200 (a) must have ducts...

  6. 46 CFR 154.1205 - Mechanical ventilation system: Standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Mechanical ventilation system: Standards. 154.1205... Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each exhaust type mechanical ventilation system required under § 154.1200 (a) must have ducts...

  7. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent...

  8. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the...

  9. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent...

  10. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the...

  11. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings...

  12. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings...

  13. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the...

  14. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings...

  15. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent...

  16. THE MECHANICS OF LUNG TISSUE UNDER HIGH-FREQUENCY VENTILATION

    E-print Network

    THE MECHANICS OF LUNG TISSUE UNDER HIGH-FREQUENCY VENTILATION MARKUS R. OWEN AND MARK A. LEWIS Abstract. High frequency ventilation is a radical departure from conventional lung ventilation question concerns ventilator induced damage to the lung tissue, and a clear protocol for the most effective

  17. 30 CFR 77.1911 - Ventilation of slopes and shafts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Ventilation of slopes and shafts. 77.1911...Slope and Shaft Sinking § 77.1911 Ventilation of slopes and shafts. (a) All...shafts shall be ventilated by mechanical ventilation equipment during development....

  18. 30 CFR 77.1911 - Ventilation of slopes and shafts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Ventilation of slopes and shafts. 77.1911...Slope and Shaft Sinking § 77.1911 Ventilation of slopes and shafts. (a) All...shafts shall be ventilated by mechanical ventilation equipment during development....

  19. 46 CFR 38.20-10 - Ventilation-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Ventilation-T/ALL. 38.20-10 Section 38.20-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Venting and Ventilation § 38.20-10 Ventilation—T/ALL. (a) A power ventilation system shall be provided for compartments containing pumps, compressors, pipes,...

  20. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings...

  1. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the...

  2. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent...

  3. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings...

  4. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent...

  5. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the...

  6. Gastric rupture after bag-mask-ventilation

    PubMed Central

    Bednarz, Stephan; Filipovic, Miodrag; Schoch, Otto; Mauermann, Eckhard

    2015-01-01

    A 42 year old woman underwent bronchoscopy with procedural propofol sedation. During the procedure, the patient suffered respiratory arrest, and bag-mask ventilation was initiated. During forced mask ventilation, abdominal distention occurred. Even after correct placement of an endotracheal and a nasogastric tube, high inspiratory pressures persisted. The abdominal CT scan revealed a high amount of intraperitoneal free air. An emergent laparotomy confirmed a stomach rupture. Immediately after opening of the peritoneal cavity, peak ventilatory pressures decreased. In this case forceful bag-mask ventilation led to air insufflation into the stomach, increasing gastric pressure, and consecutive stomach rupture.

  7. Examination of Potential Benefits of an Energy Imbalance Market in the Western Interconnection

    SciTech Connect

    Milligan, M.; Clark, K.; King, J.; Kirby, B.; Guo, T.; Liu, G.

    2013-03-01

    In the Western Interconnection, there is significant interest in improving approaches to wide-area coordinated operations of the bulk electric power system, in part because of the increasing penetration of variable generation. One proposed solution is an energy imbalance market. This study focused on that approach alone, with the goal of identifying the potential benefits of an energy imbalance market in the year 2020.

  8. Social Management of Gender Imbalance in China: A Holistic Governance Framework

    PubMed Central

    Shuzhuo, Li; Zijuan, Shang; Feldman, Marcus W.

    2015-01-01

    Since the 1980s, the sex ratio at birth (abbreviated as SRB) in China has been rising and has remained extremely high. With rapid social transition, gender imbalance has become one of the most significant issues of China's social management and has raised many problems and challenges. Innovation in the management principles and public policies of social management urgently needs a new perspective of holistic governance framework. Based on the latest trends in gender imbalance, using data from China's 2010 Population Census, this paper firstly reviews China's strategic policy responses and actions concerning the governance of the male-skewed SRB. With holistic governance theory, we focus on China's “Care for Girls” campaign to analyze the current public policy system. This paper then reveals fragmentation in the current management of China's gender imbalance. Finally we propose a social management framework for addressing China's gender imbalance. The public system needs to be strengthened, and the Chinese government should focus more on vulnerable groups such as forced bachelors in rural areas, and try to bring those groups into the policy framework for governance of gender imbalance. The proposed theoretical framework may help Chinese governments at various levels to design and implement improved social management of gender imbalance issues.

  9. Line-of-sight magnetic flux imbalances caused by electric currents

    NASA Technical Reports Server (NTRS)

    Gary, G. Allen; Rabin, Douglas

    1995-01-01

    Several physical and observational effects contribute to the significant imbalances of magnetic flux that are often observed in active regions. We consider an effect not previously treated: the influence of electric currents in the photosphere. Electric currents can cause a line-of-sight flux imbalance because of the directionality of the magnetic field they produce. Currents associated with magnetic flux tubes produce larger imbalances than do smoothly-varying distributions of flux and current. We estimate the magnitude of this effect for current densities, total currents, and magnetic geometry consistent with observations. The expected imbalances lie approximately in the range 0-15%, depending on the character of the current-carying fields and the angle from which they are viewed. Observationally, current-induced flux imbalances could be indicated by a statistical dependence of the imbalance on angular distance from disk center. A general study of magnetic flux balance in active regions is needed to determine the relative importance of other- probably larger- effects such as dilute flux (too weak to measure or rendered invisible by radiative transfer effects), merging with weak background fields, and long-range connections between active regions.

  10. Using a Ventilation Controller to Optimize Residential Passive Ventilation For Energy and Indoor Air Quality

    SciTech Connect

    Turner, William; Walker, Iain

    2014-08-01

    One way to reduce the energy impact of providing residential ventilation is to use passive and hybrid systems. However, these passive and hybrid (sometimes called mixed-mode) systems must still meet chronic and acute health standards for ventilation. This study uses a computer simulation approach to examine the energy and indoor air quality (IAQ) implications of passive and hybrid ventilation systems, in 16 California climate zones. Both uncontrolled and flow controlled passive stacks are assessed. A new hybrid ventilation system is outlined that uses an intelligent ventilation controller to minimise energy use, while ensuring chronic and acute IAQ standards are met. ASHRAE Standard 62.2-2010 – the United States standard for residential ventilation - is used as the chronic standard, and exposure limits for PM2.5, formaldehyde and NO2 are used as the acute standards.The results show that controlled passive ventilation and hybrid ventilation can be used in homes to provide equivalent IAQ to continuous mechanical ventilation, for less use of energy.

  11. Can preoperative myocardial perfusion scintigraphy predict changes in left ventricular perfusion and function after coronary artery bypass graft surgery?

    PubMed Central

    Eckardt, Rozy; Kjeldsen, Bo Juel; Johansen, Allan; Grupe, Peter; Haghfelt, Torben; Thayssen, Per; Andersen, Lars Ib; Hesse, Birger

    2012-01-01

    OBJECTIVES We wanted to evaluate whether preoperative myocardial perfusion scintigraphy (MPS) could predict changes in cardiac symptoms and postoperative myocardial perfusion and left ventricular function after coronary artery bypass grafting (CABG). METHODS Ninety-two patients with stable angina pectoris (and at least one occluded coronary artery) underwent MPS before, and 6 months after, undergoing CABG. The result of the MPS was kept secret from the surgeons. RESULTS Before CABG, 90% of the patients had angina. After CABG, 97% of the patients were without symptoms. Overall graft patency was 84%. Before CABG, one patient had normal perfusion; in the rest of them the defects were classified as follows: reversible (60%), partly reversible (27%) and irreversible (12%). Following CABG, 33% had normal perfusion; in the rest the defects were reversible in 29%, partly reversible in 12% and irreversible in 26%. Left ventricular ejection fraction (LVEF), which was normal before operation in 45%, improved in 40% of all patients. The increase in LVEF was not related to the preoperative pattern of perfusion defects. Of 30 patients with normalized perfusion after CABG, 29 (97%) had reversible defects and one patient had partly reversible defects. Of 83 perfusion defects, which were normalized after CABG, 67 were reversible (81%) or partly reversible (12%). Seventy-five percent of all reversible coronary artery territories before CABG were normalized after operation. CONCLUSIONS Our results indicate that reversible or partly reversible perfusion defects at a preoperative MPS have a high chance of normalized myocardial perfusion assessed by MPS 6 months after operation. Normal perfusion is obtained almost exclusively in territories with reversible ischaemia. Symptoms improved in nearly all patients and LVEF in a significant fraction of the patients, not related to preoperative MPS. PMID:22473665

  12. Tunnel ventilation effectiveness in fire scenarios 

    E-print Network

    Colella, Francesco; Rein, Guillermo; Carvel, Ricky O; Torero, Jose L

    2010-01-01

    Throughout most of a tunnel network the ventilation behaviour may be approximated with a simple 1D flow model. However, there are some important - but relatively small - regions of the tunnel that require CFD analysis. The ...

  13. Innovative ventilation system for animal anatomy laboratory

    SciTech Connect

    Lacey, D.R.; Smith, D.C.

    1997-04-01

    A unique ventilation system was designed and built to reduce formaldehyde fumes in the large animal anatomy lab at the Vet Medical Center at Cornell University. The laboratory includes four rooms totaling 5,500 ft{sup 2}. The main room has 2,300 ft{sup 2} and houses the laboratory where up to 60 students dissect as many as 12 horses at a time. Other rooms are a cold storage locker, an animal preparation room and a smaller lab for specialized instruction. The large animal anatomy laboratory has a history of air quality complaints despite a fairly high ventilation rate of over 10 air changes/hour. The horses are embalmed, creating a voluminous source of formaldehyde and phenol vapors. Budget constraints and increasingly stringent exposure limits for formaldehyde presented a great challenge to design a ventilation system that yields acceptable air quality. The design solution included two innovative elements: air-to-air heat recovery, and focused ventilation.

  14. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111...General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent...

  15. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111...General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent...

  16. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111...General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent...

  17. EVALUATION OF VENTILATION PERFORMANCE FOR INDOOR SPACE

    EPA Science Inventory

    The paper discusses a personal-computer-based application of computational fluid dynamics that can be used to determine the turbulent flow field and time-dependent/steady-state contaminant concentration distributions within isothermal indoor space. (NOTE: Ventilation performance ...

  18. Eustachian tube function after transmyringeal ventilation.

    PubMed

    Gupta, S C; Malhotra, M; Singh, M

    2005-01-01

    This study anus at determining the effect of transmyringeal ventilation on Eustachian tube functions. Seventy ears clinically diagnosed as having otitis media with effusion or grade I and II retraction of pars-tensa of tympanic membrane were treated with antiallergics, decongestants, mucolytics, and antibiotics as required for maximum upto three months. In forty-five ears that showed neither symptomatic nor audiometric improvement, transmyringeal ventilation was restored by myringotomy and ventilation tube insertion. There after, Eustachian tube functions were assessed by using pressure equilibration test. The post-operative audiograms showed mean hearing gain of 16. 6 dB (S D±7.9) in majority (96%) of the ears. At first week 93% ears could not either totally or partially equilibrate positive or negative pressure. The percentage in the poor function group remained 91% even at the end of 6 months showing no significant effect of ventilation tube insertion on active ET functions. PMID:23120122

  19. 30 CFR 75.333 - Ventilation controls.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...for the construction of overcasts, undercasts, shaft partitions, permanent stoppings, and regulators include concrete, concrete block, brick, cinder block, tile, or steel. No ventilation controls installed after November 15, 1992,...

  20. 30 CFR 75.333 - Ventilation controls.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...for the construction of overcasts, undercasts, shaft partitions, permanent stoppings, and regulators include concrete, concrete block, brick, cinder block, tile, or steel. No ventilation controls installed after November 15, 1992,...

  1. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing cargo tanks fitted with bottom...

  2. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing cargo tanks fitted with bottom...

  3. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing cargo tanks fitted with bottom...

  4. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing cargo tanks fitted with bottom...

  5. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing cargo tanks fitted with bottom...

  6. Midlevel ventilation's constraint on tropical cyclone intensity

    E-print Network

    Tang, Brian Hong-An

    2010-01-01

    Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a TC's intensity. An idealized ...

  7. Midlevel Ventilation's Constraint on Tropical Cyclone Intensity

    E-print Network

    Tang, Brian Hong-An

    Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a tropical cyclone’s intensity. An ...

  8. A Ventilation Index for Tropical Cyclones

    E-print Network

    Tang, Brian

    An important environmental control of both tropical cyclone intensity and genesis is vertical wind shear. One hypothesized pathway by which vertical shear affects tropical cyclones is midlevel ventilation—or the flux of ...

  9. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... not less than 1/8-inch mesh. Metal watertight closures shall be provided for use when the ventilation.... Louvers or weather cowls with a double layer of wire screen of not less than 1/8-inch mesh shall...

  10. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111...General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent...

  11. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111...General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent...

  12. Floor-supply displacement ventilation system

    E-print Network

    Kobayashi, Nobukazu, 1967-

    2001-01-01

    Research on indoor environments has received more attention recently because reports of symptoms and other health complaints related to indoor environments have been increasing. Heating, ventilating, and air-conditioning ...

  13. Process control migration towards LHC ventilation functionality

    E-print Network

    Blanc, D

    2003-01-01

    The adaptation of the ventilation systems as well as the integration of equipment to fit with the new LHC ventilation requirements lead us to consider a global re-engineering of the existing control system. This, decade old process control structure is composed of elements which are mixed between industrial and home made devices. The proposed modifications are made in order to upgrade the present control system and to provide efficient and well adapted control architecture to integrate the LHC ventilation equipment of the injection tunnels. Moreover, we need a plan for the next fifteen years of the LHC life cycle. The document is to present the situation of the present control system of the LEP ventilation process and to propose a plan for the migration of the control architecture. This is done considering the fact that elements of the present control infrastructure could no longer be supported from 2003 and major components must be removed from the CERN communication infrastructure.

  14. Scale model studies of displacement ventilation

    E-print Network

    Okutan, Galip Mehmet

    1995-01-01

    Displacement ventilation is an air conditioning method that provides conditioned air to indoor environments with the goal to improve air quality while reducing energy consumption. This study investigates the performance ...

  15. Perioperative lung protective ventilation in obese patients.

    PubMed

    Fernandez-Bustamante, Ana; Hashimoto, Soshi; Serpa Neto, Ary; Moine, Pierre; Vidal Melo, Marcos F; Repine, John E

    2015-01-01

    The perioperative use and relevance of protective ventilation in surgical patients is being increasingly recognized. Obesity poses particular challenges to adequate mechanical ventilation in addition to surgical constraints, primarily by restricted lung mechanics due to excessive adiposity, frequent respiratory comorbidities (i.e. sleep apnea, asthma), and concerns of postoperative respiratory depression and other pulmonary complications. The number of surgical patients with obesity is increasing, and facing these challenges is common in the operating rooms and critical care units worldwide. In this review we summarize the existing literature which supports the following recommendations for the perioperative ventilation in obese patients: (1) the use of protective ventilation with low tidal volumes (approximately 8 mL/kg, calculated based on predicted -not actual- body weight) to avoid volutrauma; (2) a focus on lung recruitment by utilizing PEEP (8-15 cmH2O) in addition to recruitment maneuvers during the intraoperative period, as well as incentivized deep breathing and noninvasive ventilation early in the postoperative period, to avoid atelectasis, hypoxemia and atelectrauma; and (3) a judicious oxygen use (ideally less than 0.8) to avoid hypoxemia but also possible reabsorption atelectasis. Obesity poses an additional challenge for achieving adequate protective ventilation during one-lung ventilation, but different lung isolation techniques have been adequately performed in obese patients by experienced providers. Postoperative efforts should be directed to avoid hypoventilation, atelectasis and hypoxemia. Further studies are needed to better define optimum protective ventilation strategies and analyze their impact on the perioperative outcomes of surgical patients with obesity. PMID:25907273

  16. Recovering Energy From Ventilation and Process Airstreams 

    E-print Network

    Cheney, W. A.

    1986-01-01

    cleaners for exhaust ventilation systems to permit recirculation. 2. Placing heat exchangers in process stacks and general ventilation air streams, and 3. Collecting hydrocarbon contaminants from process stacks and reusing or selling them.... In this paper I will touch on condensa tion and electrostatic precipitation as methods that can be used to collect and reuse in some form, hydrocarbons from process stacks. HEAT EXCHANGERS Plate-~ype, air-to-air heat exchangers move hot, dirty exhaust...

  17. Sensor-based demand controlled ventilation

    SciTech Connect

    De Almeida, A.T.; Fisk, W.J.

    1997-07-01

    In most buildings, occupancy and indoor pollutant emission rates vary with time. With sensor-based demand-controlled ventilation (SBDCV), the rate of ventilation (i.e., rate of outside air supply) also varies with time to compensate for the changes in pollutant generation. In other words, SBDCV involves the application of sensing, feedback and control to modulate ventilation. Compared to ventilation without feedback, SBDCV offers two potential advantages: (1) better control of indoor pollutant concentrations; and (2) lower energy use and peak energy demand. SBDCV has the potential to improve indoor air quality by increasing the rate of ventilation when indoor pollutant generation rates are high and occupants are present. SBDCV can also save energy by decreasing the rate of ventilation when indoor pollutant generation rates are low or occupants are absent. After providing background information on indoor air quality and ventilation, this report provides a relatively comprehensive discussion of SBDCV. Topics covered in the report include basic principles of SBDCV, sensor technologies, technologies for controlling air flow rates, case studies of SBDCV, application of SBDCV to laboratory buildings, and research needs. SBDCV appears to be an increasingly attractive technology option. Based on the review of literature and theoretical considerations, the application of SBDCV has the potential to be cost-effective in applications with the following characteristics: (a) a single or small number of dominant pollutants, so that ventilation sufficient to control the concentration of the dominant pollutants provides effective control of all other pollutants; (b) large buildings or rooms with unpredictable temporally variable occupancy or pollutant emission; and (c) climates with high heating or cooling loads or locations with expensive energy.

  18. Evaluating Ventilation Systems for Existing Homes

    SciTech Connect

    Aldrich, Robb; Arena, Lois

    2013-02-01

    In an effort to improve housing options near Las Vegas, Nevada, the Clark County Community Resources Division (CCCRD) performs substantial renovations to foreclosed homes. After dramatic energy, aesthetic, and health and safety improvements are made, homes are rented or sold to qualified residents. This report describes the evaluation and selection of ventilation systems for these homes, including key considerations when selecting an ideal system. The report then describes CCCRD’s decision process with respect to ventilation.

  19. Demand Controlled Ventilation for Improved Humidity Control 

    E-print Network

    Rogers, J. K.

    1996-01-01

    Ventilation for Improved Humidity Control James K. Rogers, P.E. One Blacksmith Road Chelmsford, Massachusetts ABSTRACT Recently introduced technology makes it possible to continuously monitor for humidity in numerous buildmg areas using a multi..., outside air can be minimized without exceeding recommended IAQ guidelines. INTRODUCTION The greatest single contributor to building energy loads in humid climates is the cooling and dehumidifying of outside air which is brought in for ventilation...

  20. Clinical review: Long-term noninvasive ventilation

    PubMed Central

    Robert, Dominique; Argaud, Laurent

    2007-01-01

    Noninvasive positive ventilation has undergone a remarkable evolution over the past decades and is assuming an important role in the management of both acute and chronic respiratory failure. Long-term ventilatory support should be considered a standard of care to treat selected patients following an intensive care unit (ICU) stay. In this setting, appropriate use of noninvasive ventilation can be expected to improve patient outcomes, reduce ICU admission, enhance patient comfort, and increase the efficiency of health care resource utilization. Current literature indicates that noninvasive ventilation improves and stabilizes the clinical course of many patients with chronic ventilatory failure. Noninvasive ventilation also permits long-term mechanical ventilation to be an acceptable option for patients who otherwise would not have been treated if tracheostomy were the only alternative. Nevertheless, these results appear to be better in patients with neuromuscular/-parietal disorders than in chronic obstructive pulmonary disease. This clinical review will address the use of noninvasive ventilation (not including continuous positive airway pressure) mainly in diseases responsible for chronic hypoventilation (that is, restrictive disorders, including neuromuscular disease and lung disease) and incidentally in others such as obstructive sleep apnea or problems of central drive. PMID:17419882