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. Reverse ventilation--perfusion mismatch

    SciTech Connect

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients.

  5. 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.

  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. Combined MR Proton Lung Perfusion/Angiography and Helium Ventilation

    PubMed Central

    Zheng, Jie; Leawoods, Jason C.; Nolte, Mark; Yablonskiy, Dmitriy A.; Woodard, Pamela K.; Laub, Gerhardt; Gropler, Robert J.; Conradi, Mark S.

    2007-01-01

    Three-dimensional (3D) perfusion imaging allows the assessment of pulmonary blood flow in parenchyma and main pulmonary arteries simultaneously. MRI using laser-polarized 3He gas clearly shows the ventilation distribution with high signal-to-noise ratio (SNR). In this report, the feasibility of combined lung MR angiography, perfusion, and ventilation imaging is demonstrated in a porcine model. Ultrafast gradient-echo sequences have been used for 3D perfusion and angiographic imaging, in conjunction with the use of contrast agent injections. 2D multiple-section 3He imaging was performed subsequently by inhalation of 450 ml of hyperpolarized 3He gas. The MR techniques were examined in a series of porcine models with externally delivered pulmonary emboli and/or airway occlusions. With emboli, perfusion deficits without ventilation defects were observed; airway occlusion resulted in matched deficits in perfusion and ventilation. High-resolution MR angiography can unambiguously reveal the location and size of the blood emboli. The combination of the three imaging methods may provide complementary information on abnormal lung anatomy and function. PMID:11870828

  8. 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…

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

    E-print Network

    Warren, Joe

    Lobe-based Estimating Ventilation and Perfusion from 3D CT scans of the Lungs Travis McPhail Joe are the ventilation (air flow) and perfusion (blood flow) in the patient's lungs. Given the flow of air and blood as possible. The current state of the art technology for assessing the ventilation in a patient's lungs

  11. 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.

  12. Ventilation and perfusion magnetic resonance imaging of the lung

    PubMed Central

    Bauman, Grzegorz; Eichinger, Monika

    2012-01-01

    Summary A close interaction between the respiratory pump, pulmonary parenchyma and blood circulation is essential for a normal lung function. Many pulmonary diseases present, especially in their initial phase, a variable regional impairment of ventilation and perfusion. In the last decades various techniques have been established to measure the lung function. Besides the global pulmonary function tests (PFTs) imaging techniques gained increasing importance to detect local variations in lung function, especially for ventilation and perfusion assessment. Imaging modalities allow for a deeper regional insight into pathophysiological processes and enable improved planning of invasive procedures. In contrast to computed tomography (CT) and the nuclear medicine techniques, magnetic resonance imaging (MRI), as a radiation free imaging modality gained increasing importance since the early 1990 for the assessment of pulmonary function. The major inherent problems of lung tissue, namely the low proton density and the pulmonary and cardiac motion, were overcome in the last years by a constant progress in MR technology. Some MR techniques are still under development, a process which is driven by scientific questions regarding the physiology and pathophysiology of pulmonary diseases, as well as by the need for fast and robust clinically applicable imaging techniques as safe therapy monitoring tools. MRI can be considered a promising ionizing-free alternative to techniques like CT or nuclear medicine techniques for the evaluation of lung function. The goal of this article is to provide an overview on selected MRI techniques for the assessment of pulmonary ventilation and perfusion. PMID:22802864

  13. Gas exchange and ventilation-perfusion relationships in the lung.

    PubMed

    Petersson, Johan; Glenny, Robb W

    2014-10-01

    This review provides an overview of the relationship between ventilation/perfusion ratios and gas exchange in the lung, emphasising basic concepts and relating them to clinical scenarios. For each gas exchanging unit, the alveolar and effluent blood partial pressures of oxygen and carbon dioxide (PO2 and PCO2) are determined by the ratio of alveolar ventilation to blood flow (V'A/Q') for each unit. Shunt and low V'A/Q' regions are two examples of V'A/Q' mismatch and are the most frequent causes of hypoxaemia. Diffusion limitation, hypoventilation and low inspired PO2 cause hypoxaemia, even in the absence of V'A/Q' mismatch. In contrast to other causes, hypoxaemia due to shunt responds poorly to supplemental oxygen. Gas exchanging units with little or no blood flow (high V'A/Q' regions) result in alveolar dead space and increased wasted ventilation, i.e. less efficient carbon dioxide removal. Because of the respiratory drive to maintain a normal arterial PCO2, the most frequent result of wasted ventilation is increased minute ventilation and work of breathing, not hypercapnia. Calculations of alveolar-arterial oxygen tension difference, venous admixture and wasted ventilation provide quantitative estimates of the effect of V'A/Q' mismatch on gas exchange. The types of V'A/Q' mismatch causing impaired gas exchange vary characteristically with different lung diseases. PMID:25063240

  14. Changes in distribution of lung perfusion and ventilation at rest and during maximal exercise.

    PubMed

    Mohsenifar, Z; Ross, M D; Waxman, A; Goldbach, P; Koerner, S K

    1985-03-01

    A new method for evaluation of changes in the distribution of pulmonary perfusion and ventilation during exercise was applied to normal male volunteers. Ventilation and perfusion scans were done with the subjects seated on a bicycle ergometer. The resting studies utilized krypton 81 (81mKr) for ventilation and technetium 99m (99mTc) macroaggregate albumin intravenously for perfusion. Exercise studies were done when 80 percent of maximum predicted heart rate was maintained for five minutes and utilized 81mKr for ventilation and a tenfold dose of 99mTc for perfusion. Higher dose of 99mTc would minimize the effect of radioactivity left over from the resting study. This method allowed us to assess changes in ventilation and perfusion in normal subjects induced by exercise, but may also be applicable in a variety of cardiopulmonary conditions that affect pulmonary ventilation and perfusion or both. PMID:3971762

  15. Regional ventilation/perfusion mismatch pattern in patient with Swyer James (MacLeod's) syndrome.

    PubMed

    Sager, Sait; Asa, Sertac; Akyel, Re?it; Atahan, Ersan; Kanmaz, Bedii

    2014-09-01

    Swyer James (McLeod's) syndrome (SJMS) is an uncommon disease, which occurs as a result of childhood bronchiolitis obliterans. Patients may not be diagnosed until later in their life. A 46-year-old man underwent ventilation/perfusion scintigraphy for acute onset of dyspnea. The scan showed markedly diminished ventilation and perfusion unilaterally on the right middle and inferior lobes. However, mismatched ventilation-perfusion pattern was shown on the upper right lobe, which was consistent with pulmonary embolism. Unilaterally matched ventilation/perfusion defect can see in SJMS in lung scintigraphy; however, when pulmoner embolism may accompany, scintigraphy should be carefully examined. PMID:25535507

  16. Regional ventilation/perfusion mismatch pattern in patient with Swyer James (MacLeod's) syndrome

    PubMed Central

    Sager, Sait; Asa, Sertac; Akyel, Re?it; Atahan, Ersan; Kanmaz, Bedii

    2014-01-01

    Swyer James (McLeod's) syndrome (SJMS) is an uncommon disease, which occurs as a result of childhood bronchiolitis obliterans. Patients may not be diagnosed until later in their life. A 46-year-old man underwent ventilation/perfusion scintigraphy for acute onset of dyspnea. The scan showed markedly diminished ventilation and perfusion unilaterally on the right middle and inferior lobes. However, mismatched ventilation-perfusion pattern was shown on the upper right lobe, which was consistent with pulmonary embolism. Unilaterally matched ventilation/perfusion defect can see in SJMS in lung scintigraphy; however, when pulmoner embolism may accompany, scintigraphy should be carefully examined. PMID:25535507

  17. Reporting ventilation-perfusion lung scintigraphy: impact on subsequent use of anticoagulation therapy

    Microsoft Academic Search

    P. Kaboli; J. R. Buscombe; P. J. Ell

    1993-01-01

    Ventilation and perfusion lung scintigraphy is an established and safe noninvasive technique which has been used for nearly 30 years to establish the diagnosis of pulmonary embolism. Recently, in common with other diagnostic tests, there has arisen the need to reassess the effectiveness of this test in the clinical setting. A retrospective analysis of 244 patients undergoing ventilation-perfusion lung scintigraphy

  18. Idiopathic pulmonary fibrosis. A rare cause of scintigraphic ventilation-perfusion mismatch

    SciTech Connect

    Pochis, W.T.; Krasnow, A.Z.; Collier, B.D.; Mewissen, M.W.; Almagro, U.A.; Hellman, R.S.; Isitman, A.T. (Medical College of Wisconsin, Milwaukee (USA))

    1990-05-01

    A case of idiopathic pulmonary fibrosis with multiple areas of mismatch on ventilation-perfusion lung imaging in the absence of pulmonary embolism is presented. Idiopathic pulmonary fibrosis is one of the few nonembolic diseases producing a pulmonary ventilation-perfusion mismatch. In this condition, chest radiographs may not detect the full extent of disease, and xenon-133 ventilation imaging may be relatively insensitive to morbid changes in small airways. Thus, when examining patients with idiopathic pulmonary fibrosis, one should be aware that abnormal perfusion imaging patterns without matching ventilation abnormalities are not always due to embolism. In this setting, contrast pulmonary angiography is often needed for accurate differential diagnosis.

  19. Teaching ventilation/perfusion relationships in the lung

    NSDL National Science Digital Library

    Robb W Glenny (University of Washington Medicine and Physiology and Biophysics)

    2008-07-09

    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 single lung unit and then adding additional units representing shunting, mismatch, and deadspace. Second, use simplified analogies, such as a bathtub, to help students conceptualize new ideas. Third, introduce the concept of alveolar to arterial O2 differences and the mechanisms for increasing differences as additional lung units are added. Fourth, use the consistent thread of causes of hypoxemia through the lecture to maintain continuity and provide clinical relevance. Finally, use clinically relevant examples at each step and solidify new concepts by discussing differential diagnoses at the end of the lecture(s).

  20. Apocynin attenuates ventilator-induced lung injury in an isolated and perfused rat lung model

    Microsoft Academic Search

    Chi-Huei Chiang; Chiao-Hui Chuang; Shiou-Ling Liu; Tzong-Shyuan Lee; Yu Ru Kou; Haibo Zhang

    Rationale  Apocynin suppresses the generation of reactive oxygen species (ROS) that are implicated in ventilator-induced lung injury\\u000a (VILI). We thus hypothesized that apocynin attenuates VILI.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  VILI was induced by mechanical ventilation with tidal volume (V\\u000a t) of 15 ml\\/kg in isolated and perfused rat lung. Apocynin was administered in the perfusate at onset of mechanical ventilation.\\u000a A group ventilated with low V

  1. The effect of omalizumab on ventilation and perfusion in adults with allergic asthma

    PubMed Central

    Kelmenson, Daniel A; Kelly, Vanessa J; Winkler, Tilo; Kone, Mamary T; Musch, Guido; Melo, Marcos F Vidal; Venegas, Jose G; Harris, R Scott

    2013-01-01

    Omalizumab promotes clinical improvement in patients with allergic asthma, but its effect on pulmonary function is unclear. One possibility is that omalizumab improves asthma symptoms through effects on the regional distributions of ventilation, perfusion, and ventilation/perfusion matching, metrics which can be assessed with Nitrogen-13-saline Position Emission Tomography (PET). Four adults with moderate to severe uncontrolled allergic asthma underwent symptom assessment, spirometry and functional pulmonary imaging with Nitrogen-13-saline PET before and after 4-5 months of treatment with omalizumab. PET imaging was used to determine ventilation/perfusion ratios, the heterogeneity (coefficient of variation, COV) of ventilation and perfusion, and lung regions with ventilation defects. There were no significant changes in spirometry values after omalizumab treatment, but there was a trend towards an improvement in symptom scores. There was little change in the matching of ventilation and perfusion. The COV of perfusion was similar before and after omalizumab treatment. The COV of ventilation was also similar before (0.57 (0.28)) and after (0.66 (0.13)) treatment, and it was similar to previously published values for healthy subjects. There was a non-significant trend towards an increase in the extent of ventilation defects after omalizumab treatment, from 5 (15)% to 12.8 (14.7)%. Treatment of moderate to severe uncontrolled allergic asthma with omalizumab did not result in a significant improvement in ventilation and perfusion metrics assessed with functional PET imaging. The normal COV of ventilation which was unaffected by treatment supports the hypothesis that omalizumab exerts its clinical effect on lung function during allergen exposure rather than in between exacerbations. PMID:23901360

  2. Ventilation-perfusion scan in the acutely ill patient with unilateral hyperlucent lung

    SciTech Connect

    Miller, M.B.; Caride, V.J.

    1988-01-01

    A patient with a unilateral hyperlucent lung with acute respiratory complaints is presented. A ventilation-perfusion scan was performed to rule out pulmonary embolism. The perfusion scan ( (/sup 99m/TC)MAA) showed peripheral perfusion defects in the hyperlucent lung. The ventilation study (/sup 133/Xe) demonstrated peripheral ventilatory defects on the single breath image in the hyperlucent lung, the filling in of these on the equilibrium view, and diffusely delayed washout in the affected lung. These findings were suggestive of the Swyer-James syndrome and critical in excluding the numerous other causes of unilateral hyperlucent lung, which are discussed. The importance of the ventilation-perfusion study (and particularly the ventilation scan) in the patient with unilateral hyperlucent lung and acute respiratory symptoms is stressed. In addition, a discussion of the Swyer-James syndrome is included.

  3. Ventilation and perfusion scans in the preoperative assessment of bronchial carcinoma.

    PubMed Central

    Lipscomb, D J; Pride, N B

    1977-01-01

    Ventilation (krypton -81m) and perfusion (technetium -99m) lung scans were obtained in a consecutive series of 21 patients shortly before thoracotomy for proven or suspected carcinoma of the bronchus. In most patients ventilation and perfusion were impaired equally and the scan abnormality corresponded to the bronchoscopic and radiological findings. Unexpectedly large defects in the perfusion scan were seen in three patients, all of whom had extensive neoplastic involvement of the mediastinum at thoracotomy, but 11 other patients had mediastinal involvement which was not suspected from the scan. Ventilation scanning was useful in the prediction of postoperative ventilatory capacity in two patients who underwent pneumonectomy. We conclude that ventilation and perfusion scans are not sensitive indicators of neoplastic involvement of the mediastinum but they are valuable for the prediction of postoperative lung function. PMID:601734

  4. Effect of PEEP on regional ventilation and perfusion in the mechanically ventilated preterm lamb

    SciTech Connect

    Schlessel, J.S.; Susskind, H.; Joel, D.D.; Bossuyt, A.; Harrold, W.H.; Zanzi, I.; Chanana, A.D. (Cornell Univ. Medical College, Manhasset, NY (USA))

    1989-08-01

    Improvement of gas exchange through closer matching of regional ventilation (V) and lung perfusion (Q) with the application of positive end-expiratory pressure (PEEP) was evaluated in vivo in six mechanically ventilated preterm lambs (107-126 days/145 days gestation). Changes in V and Q were determined from in vivo scintigraphic measurements in four lung regions with inhaled radioactive 81mKr, and infused {sup 81m}Kr/dextrose and/or ({sup 99m}Tc)MAA as PEEP was applied at 2, 4, and 6 cm H{sub 2}O in each animal. Dynamic compliance varied between 0.02 and 0.40 ml/cm H{sub 2}O, which was consistent with surfactant deficiency. As PEEP was increased, the regional distribution of Q shifted from the rostral to the caudal lung regions (p less than 0.02 to less than 0.05), while that of V remained unchanged. Regional V/Q matching improved together with a trend towards improvement of arterial blood gases as PEEP was increased from 2 to 4 cm H{sub 2}O. Pulmonary scintigraphy offers a noninvasive methodology for the quantitative assessment of regional V and Q matching in preterm lambs and may be clinically applicable to ventilated neonates.

  5. Ventilation-perfusion SPECT\\/CT in Diagnosing Swyer-James (MacLeod) Syndrome

    Microsoft Academic Search

    Tzyy-Ling Chuang; Yuh-Feng Wang; Chun-Liang Lai

    2010-01-01

    We present the characteristics of a ventilation-perfusion scan correlating to both planar and single photon emission computed tomography and computed tomography (SPECT\\/CT) images of the lungs in a patient with Swyer-James (MacLeod) syndrome. A Tc-99m MAA lung perfusion scan was recorded with multiple projections and SPECT\\/CT. In the ventilation scan, initially dynamic acquisition of aerosol Tc-99m DTPA was obtained with

  6. Tomography of regional ventilation and perfusion using krypton 81m in normal subjects and asthmatic patients

    Microsoft Academic Search

    D Orphanidou; J M Hughes; M J Myers; A R Al-Suhali; B Henderson

    1986-01-01

    Single photon emission computed tomography, a rotating gamma camera, and continuous inhalation or infusion of krypton 81m (half life 13 seconds) were used to measure regional ventilation (V), perfusion (Q), and ventilation-perfusion (V\\/Q) ratios in five normal subjects in supine, prone, and lateral decubitus postures and in three asthmatic patients (supine posture only) before and after inhalation of 2.5 mg

  7. 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

  8. Dynamic chest radiography with a flat-panel detector (FPD): ventilation-perfusion study

    NASA Astrophysics Data System (ADS)

    Tanaka, R.; Sanada, S.; Fujimura, M.; Yasui, M.; Tsuji, S.; Hayashi, N.; Okamoto, H.; Nanbu, Y.; Matsui, O.

    2011-03-01

    Pulmonary ventilation and blood flow are reflected in dynamic chest radiographs as changes in X-ray translucency, i.e., pixel values. This study was performed to investigate the feasibility of ventilation-perfusion (V/Q) study based on the changes in pixel value. Sequential chest radiographs of a patient with ventilation-perfusion mismatch were obtained during respiration using a dynamic flat-panel detector (FPD) system. The lung area was recognized and average pixel value was measured in each area, tracking and deforming the region of interest. Inter-frame differences were then calculated, and the absolute values were summed in each respiratory phase. The results were visualized as ventilation, blood flow, V/Q ratio distribution map and compared to distribution of radioactive counts on ventilation and perfusion scintigrams. In the results, abnormalities were appeared as a reduction of changes in pixel values, and a correlation was observed between the distribution of changes in pixel value and those of radioactivity counts (Ventilation; r=0.78, Perfusion; r=0.77). V/Q mismatch was also indicated as mismatch of changes in pixel value, and a correlation with V/Q calculated by radioactivity counts (r=0.78). These results indicated that the present method is potentially useful for V/Q study as an additional examination in conventional chest radiography.

  9. Perfusion and ventilation filters for Fourier-decomposition MR lung imaging.

    PubMed

    Wujcicki, Artur; Corteville, Dominique; Materka, Andrzej; Schad, Lothar R

    2015-03-01

    MR imaging without the use of contrast agents has recently been used for creating perfusion and ventilation functional lung images. The technique incorporates frequency- or wavelet-domain filters to separate the MR signal components. This paper presents a new, subject-adaptive algorithm for perfusion and ventilation filters design. The proposed algorithm uses a lung signal model for separation of the signal components in the frequency domain. Non-stationary lung signals are handled by a short time Fourier transform. This method was applied to sets of 192 and 90 co-registered non-contrast MR lung images measured for five healthy subjects at the rate of 3,33 images per second, using different slice thicknesses. In each case, the resulted perfusion and ventilation images showed a smaller amount of mutual information, when compared to those obtained using the known lowpass/highpass filter approach. PMID:25466452

  10. Bilateral basal Xe-133 retention and ventilation/perfusion patterns in mild and subclinical congestive heart failure

    SciTech Connect

    Lee, H.K.; Skarzynski, J.J.; Spadaro, A. (Mount Sinai Services-City Hospital Center, Elmhurst, NY (USA))

    1989-12-01

    The Xe-133 ventilation pattern in congestive heart failure (CHF) was assessed using 24 inpatient ventilation/perfusion studies performed to rule out pulmonary embolism. Patients with histories of CHF, myocardial infarction (MI), and cardiomyopathy were included in the study. Frank pulmonary edema, pulmonary embolism, and other known lung diseases such as chronic obstructive lung disease, tumor, and pneumonia were excluded. Fifteen of the 24 patients had abnormal ventilation scans. Twelve of the 15 showed bilateral basal Xe-133 retention on washout; the remaining 3 showed diffuse, posterior regional retention. On perfusion scans, 14 of the 15 abnormal ventilation patients showed evidence of CHF such as inverted perfusion gradient, enlarged cardiac silhouette, or patchy perfusion, and all of them had a history of CHF or cardiac disease. Nine of the 24 patients had normal ventilation scans, including normal washout patterns. Seven of the nine had normal perfusion (p less than 0.01). Four of the nine normal ventilation patients had a history of cardiac disease or CHF but no recent acute MI. Bilateral basal regional Xe-133 retention, coupled with perfusion scan evidence of CHF such as inverted perfusion gradient, enlarged cardiac silhouette, and patchy perfusion pattern, appears to be a sensitive and characteristic ventilation/perfusion finding in mild or subclinical CHF.

  11. 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.

  12. [Calculation of the ventilation-perfusion ratio in the scintigraphic diagnosis of pulmonary embolism].

    PubMed

    Meignan, M; Rosso, J; Petitprez, P; Cinotti, L; Harf, A; Simonneau, G; Duroux, P; Galle, P

    1987-09-12

    Ventilation perfusion scanning fails to diagnose pulmonary embolism in matched defects. In 61 patients (19 with pulmonary embolism proved by angiography, 32 with chronic obstructive lung disease and 10 with acute bacterial pneumonia) we computed the ventilation perfusion ratio (V/Q) in these matched defects, using Krypton 81 m. This analysis demonstrated that the diagnosis of pulmonary embolism could be made with a specificity of 100% when the V/Q ratio was greater than 1.2 in the matched defects. Pulmonary embolism was characterized by a perfusion defect with a high V/Q ratio, even in Laennec infarction. In contrast, the analysis excluded the diagnosis of pulmonary embolism and suggested another disease when the V/Q was less than 0.95 with a specificity of 95%. Perfusion defects in acute pneumonia always had a V/Q less than 1. The diagnosis remained difficult in chronic obstructive lung disease when pulmonary embolism was suspected on subsegmental defects. Nevertheless this could be solved in about 50% of the cases by quantitative analysis. We feel, therefore, that ventilation perfusion scanning should be quantified by V/Q analysis to improve the diagnosis of pulmonary embolism. PMID:2958794

  13. Ventilation/perfusion lung scan in pulmonary veno-occlusive disease.

    PubMed

    Seferian, Andrei; Helal, Badia; Jaïs, Xavier; Girerd, Barbara; Price, Laura C; Günther, Sven; Savale, Laurent; Dorfmüller, Peter; Parent, Florence; Sitbon, Olivier; Humbert, Marc; Simonneau, Gérald; Montani, David

    2012-07-01

    Pulmonary veno-occlusive disease (PVOD), a rare form of pulmonary arterial hypertension (PAH), requires histological proof for definitive diagnosis; however, lung biopsy is not recommended in PAH. Recent conjoint European Respiratory Society/European Society of Cardiology guidelines suggest that nonmatched perfusion defects on ventilation/perfusion (V'/Q') lung scanning in PAH patients may suggest PVOD. The aim of our study was to evaluate V'/Q' lung scans in a large cohort of PVOD and idiopathic or heritable PAH patients. V'/Q' lung scans from 70 patients with idiopathic or heritable PAH and 56 patients with confirmed or highly probable PVOD were reviewed in a double-blind manner. The vast majority of V'/Q' lung scans were normal or without significant abnormalities in both groups. No differences in ventilation or perfusion lung scans were observed between PAH and PVOD patients (all p>0.05). Furthermore, no differences were observed between confirmed (n=31) or highly probable PVOD (n=25). Nonmatched perfusion defects were found in seven (10%) idiopathic PAH patients and four (7.1%) PVOD patients (p>0.05). Nonmatched perfusion defects were rarely seen in a large cohort of idiopathic or heritable PAH and PVOD patients. Future recommendations should be amended according to these results suggesting that V'/Q' lung scanning is not useful in discriminating PVOD from idiopathic PAH. PMID:22088969

  14. Regional distribution of lung perfusion and ventilation at rest and during steady-state exercise after unilateral lung transplantation.

    PubMed

    Ross, D J; Waters, P F; Waxman, A D; Koerner, S K; Mohsenifar, Z

    1993-07-01

    Cardiopulmonary exercise testing has previously demonstrated a reduced maximum oxygen uptake and anaerobic threshold, as well as abnormal wasted ventilation fraction and gas exchange after unilateral lung transplantation. To further explain the mechanisms of these abnormalities, we assessed the regional distribution of pulmonary blood flow and ventilation at rest and during steady-state exercise in nine recipients of unilateral lung transplants. Krypton-81 (81mKr) aerosol and technetium-99m (99mTc) were utilized to assess lung ventilation (V) and perfusion (Q), respectively. The digitalized images were trisected to analyze apical, mid-, and basilar lung perfusion and ventilation in both the transplanted and native lung, both at rest and steady-state upright exercise. Results were compared with previously reported data obtained in normal subjects in our laboratory using the identical technique. At rest, 75 +/- 13 percent of perfusion was directed to the transplanted lung; however, the corresponding fractional ventilation was only 67 +/- 14 percent. During exercise, there was no significant change in fractional perfusion or ventilation. Resting apical perfusion in the transplanted lung was higher than normal in four patients and comparable to normal in five patients. In contrast to the augmentation of apical perfusion observed in normal subjects during upright exercise, none of our patients increased the regional perfusion to the apices during exercise in either transplanted or native lungs. These unexpected responses suggest either more maximal allograft apical recruitment at rest due to the increased allograft perfusion or an abnormality in the apical pulmonary vasculature after transplantation. Furthermore, the relative mismatch in ventilation and perfusion in transplanted and native lungs suggests regions of high V/Q in the native, and low V/Q in the transplanted lung. This mismatch is most pronounced in recipients of single lung transplants for pulmonary vascular disease. PMID:8325055

  15. Perfusion and ventilation isotope lung scans in constrictive bronchiolitis obliterans. A series of three cases.

    PubMed

    Hasegawa, Yoshinori; Imaizumi, Kazuyoshi; Sekido, Yoshitaka; Iinuma, Yoshitsugu; Kawabe, Tsutomu; Hashimoto, Naozumi; Shimokata, Kaoru

    2002-01-01

    Constrictive bronchiolitis obliterans (BO) has been defined as a syndrome of airflow limitation due to bronchiolar and peribronchiolar inflammation and fibrosis. However, chest roentgenograms are frequently normal, and alternative radiographic evaluation or other manifestations of the disease would be required. Here we report three patients with BO. We performed a technetium-99(m)-labeled macroaggregate human albumin lung perfusion scan and a ventilation scan using krypton-81(m). We observed multiple matched defects in the perfusion and ventilation scans in these patients, which represent narrowing or obliteration of the bronchiolar lumen and its adjacent pulmonary arteriole. We propose that this is a useful diagnostic approach for an imaging study of BO. PMID:12457011

  16. A novel quantitative dual-isotope method for simultaneous ventilation and perfusion lung SPET

    Microsoft Academic Search

    Alejandro Sánchez-Crespo; Johan Petersson; Sven Nyren; Margareta Mure; Robb W. Glenny; Jan-Olov Thorell; Hans Jacobsson; Sten G. Lindahl; Stig A. Larsson

    2002-01-01

    A quantitative dual-isotope single-photon emission tomography (SPET) technique for the assessment of lung ventilation (V) and perfusion (Q) using, respectively, technetium-99m labelled Technegas (140 keV) and indium-113m labelled macro-aggregated albumin (392 keV), is presented, validated and clinically tested in a healthy volunteer. In order to assess V, Q and V\\/Q distributions in quantitative terms, algorithms which correct for down scattering,

  17. Ventilation/Perfusion Imaging in a Rat Model of Airway Obstruction

    PubMed Central

    Mistry, Nilesh N.; Qi, Yi; Hedlund, Laurence W.; Johnson, G. Allan

    2009-01-01

    The global increase in asthma, chronic obstructive pulmonary disease, and other pulmonary diseases has stimulated interest in rat models of pulmonary disease. Imaging methods for study of these models is particularly appealing, since the results can be translated to the clinical setting. Comprehensive understanding of lung function can be achieved by performing registered pulmonary ventilation and perfusion imaging studies in the same animal. While ventilation imaging has been addressed for small animals, quantitative pulmonary perfusion imaging has not been feasible until recently with our proposed technique for quantitative perfusion imaging using multiple contrast agent injections and a view-sharing radial imaging technique. Here, we combine the method with registered ventilation imaging using hyperpolarized 3He in an airway obstruction rodent model. To our knowledge, this is the first comprehensive quantitative assessment of lung function in small animals at high spatial resolution. Standard deviation of the Log (V/Q) is used as a quantitative biomarker to differentiate heterogeneity between the control and treatment group. The estimated value of the biomarker lies with the normal range of values reported in the literature. The biomarker that was extracted using the imaging technique described in this work showed statistically significant differences between the control rats and those with airway obstruction. PMID:20146375

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

    SciTech Connect

    Wegener, W.A.; Velchik, M.G. (Hospital of the University of Pennsylvania, Philadelphia (USA))

    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.

  19. 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.

  20. 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.

  1. Tomography of regional ventilation and perfusion using krypton 81m in normal subjects and asthmatic patients.

    PubMed Central

    Orphanidou, D; Hughes, J M; Myers, M J; Al-Suhali, A R; Henderson, B

    1986-01-01

    Single photon emission computed tomography, a rotating gamma camera, and continuous inhalation or infusion of krypton 81m (half life 13 seconds) were used to measure regional ventilation (V), perfusion (Q), and ventilation-perfusion (V/Q) ratios in five normal subjects in supine, prone, and lateral decubitus postures and in three asthmatic patients (supine posture only) before and after inhalation of 2.5 mg nebulised salbutamol. Vertical and horizontal gradients of V, Q, and V/Q were examined at three levels in each lung in regions of 1.9 cm3 size. In normal subjects V and Q increased along the axis of gravity in all postures and at all levels in the lung except for V in the prone position. Smaller horizontal gradients were found with an increase in V and Q from caudal to cranial--again except in the prone posture, where the gradient was slightly reversed. Constraint to outward motion of the ventral chest and abdominal wall is the most likely explanation for the different behaviour in the prone posture. In chronic asthma the vertical gradients of V and V/Q were the reverse of normal, but the Q gradient was normal. Bronchodilator treatment did not affect the vertical or horizontal gradients significantly, but analysis of individual regions showed that, relatively, V/Q worsened in 42% of them; this was associated in two thirds with an increase in fractional Q. After inhalation of beta agonist local vasodilatation may influence V/Q ratios in some units more than bronchodilatation. Images PMID:3491441

  2. 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.

  3. Spatial correspondence of 4D CT ventilation and SPECT pulmonary perfusion defects in patients with malignant airway stenosis

    NASA Astrophysics Data System (ADS)

    Castillo, Richard; Castillo, Edward; McCurdy, Matthew; Gomez, Daniel R.; Block, Alec M.; Bergsma, Derek; Joy, Sarah; Guerrero, Thomas

    2012-04-01

    To determine the spatial overlap agreement between four-dimensional computed tomography (4D CT) ventilation and single photon emission computed tomography (SPECT) perfusion hypo-functioning pulmonary defect regions in a patient population with malignant airway stenosis. Treatment planning 4D CT images were obtained retrospectively for ten lung cancer patients with radiographically demonstrated airway obstruction due to gross tumor volume. Each patient also received a SPECT perfusion study within one week of the planning 4D CT, and prior to the initiation of treatment. Deformable image registration was used to map corresponding lung tissue elements between the extreme component phase images, from which quantitative three-dimensional (3D) images representing the local pulmonary specific ventilation were constructed. Semi-automated segmentation of the percentile perfusion distribution was performed to identify regional defects distal to the known obstructing lesion. Semi-automated segmentation was similarly performed by multiple observers to delineate corresponding defect regions depicted on 4D CT ventilation. Normalized Dice similarity coefficient (NDSC) indices were determined for each observer between SPECT perfusion and 4D CT ventilation defect regions to assess spatial overlap agreement. Tidal volumes determined from 4D CT ventilation were evaluated versus measurements obtained from lung parenchyma segmentation. Linear regression resulted in a linear fit with slope = 1.01 (R2 = 0.99). Respective values for the average DSC, NDSC1 mm and NDSC2 mm for all cases and multiple observers were 0.78, 0.88 and 0.99, indicating that, on average, spatial overlap agreement between ventilation and perfusion defect regions was comparable to the threshold for agreement within 1-2 mm uncertainty. Corresponding coefficients of variation for all metrics were similarly in the range: 0.10%-19%. This study is the first to quantitatively assess 3D spatial overlap agreement between clinically acquired SPECT perfusion and specific ventilation from 4D CT. Results suggest high correlation between methods within the sub-population of lung cancer patients with malignant airway stenosis.

  4. Characterization of the Isolated, Ventilated, and Instrumented Mouse Lung Perfused with Pulsatile Flow

    PubMed Central

    Vanderpool, Rebecca R.; Chesler, Naomi C.

    2011-01-01

    The isolated, ventilated and instrumented mouse lung preparation allows steady and pulsatile pulmonary vascular pressure-flow relationships to be measured with independent control over pulmonary arterial flow rate, flow rate waveform, airway pressure and left atrial pressure. Pulmonary vascular resistance is calculated based on multi-point, steady pressure-flow curves; pulmonary vascular impedance is calculated from pulsatile pressure-flow curves obtained at a range of frequencies. As now recognized clinically, impedance is a superior measure of right ventricular afterload than resistance because it includes the effects of vascular compliance, which are not negligible, especially in the pulmonary circulation. Three important metrics of impedance - the zero hertz impedance Z0, the characteristic impedance ZC, and the index of wave reflection RW - provide insight into distal arterial cross-sectional area available for flow, proximal arterial stiffness and the upstream-downstream impedance mismatch, respectively. All results obtained in isolated, ventilated and perfused lungs are independent of sympathetic nervous system tone, volume status and the effects of anesthesia. We have used this technique to quantify the impact of pulmonary emboli and chronic hypoxia on resistance and impedance, and to differentiate between sites of action (i.e., proximal vs. distal) of vasoactive agents and disease using the pressure dependency of ZC. Furthermore, when these techniques are used with the lungs of genetically engineered strains of mice, the effects of molecular-level defects on pulmonary vascular structure and function can be determined. PMID:21559007

  5. 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

  6. 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.

  7. 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.

  8. Regional measurement of ventilation and perfusion to detect subtle lung abnormalities in coal miners

    SciTech Connect

    Susskind, H.; Liu, J.; Brill, A.B.

    1986-03-01

    The relationship between regional pulmonary ventilation (V) and perfusion (Q) uniquely determines the amount of gas exchange that occurs in the lungs. Therefore, the pixel-by-pixel distributions of V and Q were measured with continuously inhaled Kr-81m and i.v. injected Tc-99m MAA, respectively, in a group of 71 subjects exposed to coal dust and then compared with those from a control group of 9 healthy volunteers. Each subject sat upright with his back against a large-field-of-view scintillation camera; 500,000 count images were obtained, analyzed by computer, and then displayed in a 64 x 64 matrix. Individual pixel values of V and Q were correlated by a best-fit regression line, whose slope was proportional to the overall V/Q ratio. The slopes of individual groups of nonsmokers, ex-smokers, and smokers (0.83-0.85) were significantly greater (p < 0.02) than the slope of the controls (0.70 +/- 0.07). In addition, the authors found that the skewness of plots of frequency distribution of V/Q and of V and Q vs V/Q for the individual patient groups was statistically different from that of the normals (p < 0.01). Statistical analysis of local and Q values therefore appears to be a potentially useful, non-invasive method to evaluate subtle regional lung impairment.

  9. A Short Period of Ventilation without Perfusion Seems to Reduce Atelectasis without Harming the Lungs during Ex Vivo Lung Perfusion

    PubMed Central

    Pierre, Leif

    2013-01-01

    To evaluate the lung function of donors after circulatory deaths (DCDs), ex vivo lung perfusion (EVLP) has been shown to be a valuable method. We present modified EVLP where lung atelectasis is removed, while the lung perfusion is temporarily shut down. Twelve pigs were randomized into two groups: modified EVLP and conventional EVLP. When the lungs had reached 37°C in the EVLP circuit, lung perfusion was temporarily shut down in the modified EVLP group, and positive end-expiratory pressure (PEEP) was increased to 10?cm H2O for 10 minutes. In the conventional EVLP group, PEEP was increased to 10?cm H2O for 10 minutes with unchanged lung perfusion. In the modified EVLP group, the arterial oxygen partial pressure (PaO2) was 18.5 ± 7.0?kPa before and 64.5 ± 6.0?kPa after the maneuver (P < 0.001). In the conventional EVLP group, the PaO2 was 16.8 ± 3.1?kPa and 46.8 ± 2.7?kPa after the maneuver (P < 0.01; P < 0.01). In the modified EVLP group, the pulmonary graft weight was unchanged, while in the conventional EVLP group, the pulmonary graft weight was significantly increased. Modified EVLP with normoventilation of the lungs without ongoing lung perfusion for 10 minutes may eliminate atelectasis almost completely without harming the lungs. PMID:24102021

  10. 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

  11. Assessment of regional lung functional impairment with co-registered respiratory-gated ventilation\\/perfusion SPET-CT images: initial experiences

    Microsoft Academic Search

    Kazuyoshi Suga; Kawakami Yasuhiko; Mohammed Zaki; Tomio Yamashita; Aska Seto; Tsuneo Matsumoto; Naofumi Matsunaga

    2004-01-01

    In this study, respiratory-gated ventilation and perfusion single-photon emission tomography (SPET) were used to define regional functional impairment and to obtain reliable co-registration with computed tomography (CT) images in various lung diseases. Using a triple-headed SPET unit and a physiological synchroniser, gated perfusion SPET was performed in a total of 78 patients with different pulmonary diseases, including metastatic nodules (

  12. Ventilation-Perfusion Scintigraphy Is More Sensitive than Multidetector CTPA in Detecting Chronic Thromboembolic Pulmonary Disease as a Treatable Cause of Pulmonary Hypertension

    Microsoft Academic Search

    Nina Tunariu; Simon J. R. Gibbs; Zarni Win; Wendy Gin-Sing; Alison Graham; Philip Gishen; Adil AL-Nahhas

    2007-01-01

    Pulmonary hypertension (PH) is a progressive disease with a poor prognosis. Identifying chronic thromboembolic pulmonary disease as a cause of PH has major clinical implications as these patients could be potentially offered a surgical cure. Ventilation- perfusion (V\\/Q) scintigraphy has a high sensitivity to detect embolic disease but its value has been challenged with the emer- gence of multidetector CT

  13. Fluid imbalance

    MedlinePLUS

    Water imbalance ... the skin). Many medical problems can cause fluid imbalance: It is common to retain large amounts of ... results in extreme thirst and dehydration. A fluid imbalance is often associated with imbalances of sodium ( hyponatremia , ...

  14. Role of spiral volumetric computed tomographic scanning in the assessment of patients with clinical suspicion of pulmonary embolism and an abnormal ventilation\\/perfusion lung scan

    Microsoft Academic Search

    A. B. van Rossum; F. E. Treurniet; G. J. Kieft; S. J. Smith; R. Schepers-Bok

    1996-01-01

    BACKGROUND: A study was carried out to evaluate the potential place of spiral volumetric computed tomography (SVCT) in the diagnostic strategy for pulmonary embolism. METHODS: In a prospective study 249 patients with clinical suspicion of pulmonary embolism were evaluated with various imaging techniques. In all patients a ventilation\\/perfusion (V\\/Q) scan was performed. Seventy seven patients with an abnormal V\\/Q scan

  15. Mixed Acid-Base Disorders, Hydroelectrolyte Imbalance and Lactate Production in Hypercapnic Respiratory Failure: The Role of Noninvasive Ventilation

    PubMed Central

    Terzano, Claudio; Di Stefano, Fabio; Conti, Vittoria; Di Nicola, Marta; Paone, Gregorino; Petroianni, Angelo; Ricci, Alberto

    2012-01-01

    Background Hypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure. Methods Sixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO2 and PaCO2 and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV. Results Nine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7%) mixed respiratory acidosis–metabolic alkalosis, 10/36 (27.8%) respiratory acidosis and 3/5 (60%) mixed respiratory-metabolic acidosis patients (p?=?0.026), with durations of 45.1±9.8, 36.2±8.9 and 53.3±4.1 hours, respectively (p?=?0.016). The duration of ventilation was associated with higher blood lactate (p<0.001), lower pH (p?=?0.016), lower serum sodium (p?=?0.014) and lower chloride (p?=?0.038). Hyponatremia without hypervolemic hypochloremia occurred in 11 respiratory acidosis patients. Hypovolemic hyponatremia with hypochloremia and hypokalemia occurred in 10 mixed respiratory acidosis–metabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder. Conclusions Mixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated. PMID:22539963

  16. Relationships among ventilation-perfusion distribution, multiple inert gas methodology and metabolic blood-gas tensions.

    PubMed

    Lee, A S; Patterson, R W; Kaufman, R D

    1987-12-01

    The retention equations upon which the Multiple Inert Gas Method is based are derived from basic principles using elementary algebra. It is shown that widely disparate distributions produce indistinguishable sets of retentions. The limits of resolution of perfused compartments in the VA/Q distribution obtainable by the use of the multiple inert gas method are explored mathematically, and determined to be at most shunt and two alveolar compartments ("tripartite" distribution). Every continuous distribution studied produced retentions indistinguishable from those of its unique "matching" tripartite distribution. When a distribution is minimally specified, it is unique. Any additional specification (increased resolution--more compartments) of the distribution results in the existence of an infinitude of possible distributions characterized by indistinguishable sets of retention values. No further increase in resolution results from the use of more tracers. When sets of retention values were extracted from published multiple inert gas method continuous distributions, and compared with the published "measured" retention sets, substantial differences were found. This illustrates the potential errors incurred in the practical, in vivo application of the multiple inert gas method. In preliminary studies, the tripartite distribution could be determined with at least comparable accuracy by blood-gas (oxygen, carbon dioxide) measurements. PMID:2827715

  17. Ventilation-perfusion inequality in the human lung is not increased following no-decompression-stop hyperbaric exposure.

    PubMed

    Moore, Gaea Schwaebe; Wong, Stewart C; Darquenne, Chantal; Neuman, Tom S; West, John B; Kim Prisk, G

    2009-11-01

    Venous gas bubbles occur in recreational SCUBA divers in the absence of decompression sickness, forming venous gas emboli (VGE) which are trapped within pulmonary circulation and cleared by the lung without overt pathology. We hypothesized that asymptomatic VGE would transiently increase ventilation-perfusion mismatch due to their occlusive effects within the pulmonary circulation. Two sets of healthy volunteers (n = 11, n = 12) were recruited to test this hypothesis with a single recreational ocean dive or a baro-equivalent dry hyperbaric dive. Pulmonary studies (intrabreath V (A)/Q (iV/Q), alveolar dead space, and FVC) were conducted at baseline and repeat 1- and 24-h after the exposure. Contrary to our hypothesis V (A)/Q mismatch was decreased 1-h post-SCUBA dive (iV/Q slope 0.023 +/- 0.008 ml(-1) at baseline vs. 0.010 +/- 0.005 NS), and was significantly reduced 24-h post-SCUBA dive (0.000 +/- 0.005, p < 0.05), with improved V (A)/Q homogeneity inversely correlated to dive severity. No changes in V (A)/Q mismatch were observed after the chamber dive. Alveolar dead space decreased 24-h post-SCUBA dive (78 +/- 10 ml at baseline vs. 56 +/- 5, p < 0.05), but not 1-h post dive. FVC rose 1-h post-SCUBA dive (5.01 +/- 0.18 l vs. 5.21 +/- 0.26, p < 0.05), remained elevated 24-h post SCUBA dive (5.06 +/- 0.2, p < 0.05), but was decreased 1-hr after the chamber dive (4.96 +/- 0.31 L to 4.87 +/- 0.32, p < 0.05). The degree of V (A)/Q mismatch in the lung was decreased following recreational ocean dives, and was unchanged following an equivalent air chamber dive, arguing against an impact of VGE on the pulmonary circulation. PMID:19690884

  18. Ventilation\\/perfusion ratios and simultaneous dual-radionuclide single-photon emission tomography with krypton-81m and technetium-99m macroaggregated albumin

    Microsoft Academic Search

    Y. Sando; T. Inoue; R. Nagai; K. Endo

    1997-01-01

    .   To date, there has been neither a good method to clarify the three-dimensional distribution of pulmonary ventilation\\/perfusion\\u000a (V.A\\/Q.) ratios, nor a convenient way to assess V.A\\/Q. inequality. The purpose of this study was to develop a functional image of pulmonary V.A\\/Q. ratios based on data acquired with simultaneous dual-radionuclide single-photon emission tomography (SPET) and to assess\\u000a V.A\\/Q. unevenness through

  19. 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.

  20. 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 [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiation Oncology, Shaexamndong Cancer Hospital and Institute, Jinan (China); Frey, Kirk A.; Gross, Milton D. [Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Hayman, James A. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Arenberg, Doug [Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (United States); Cai Xuwei [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Ramnath, Nithya; Hassan, Khaled [Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (United States); Moran, Jean; Eisbruch, Avraham; Ten Haken, Randall K. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Kong Fengming, E-mail: fengkong@med.umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Radiation Oncology, Veterans' Affairs Health Center, Ann Arbor, Michigan (United States)

    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.

  1. A compartment model of alveolar-capillary oxygen diffusion with ventilation-perfusion gradient and dynamics of air transport through the respiratory tract.

    PubMed

    Jaworski, Jacek; Redlarski, Grzegorz

    2014-08-01

    This paper presents a model of alveolar-capillary oxygen diffusion with dynamics of air transport through the respiratory tract. For this purpose electrical model representing the respiratory tract mechanics and differential equations representing oxygen membrane diffusion are combined. Relevant thermodynamic relations describing the mass of oxygen transported into the human body are proposed as the connection between these models, as well as the influence of ventilation-perfusion mismatch on the oxygen diffusion. The model is verified based on simulation results of varying exercise intensities and statistical calculations of the results obtained during various clinical trials. The benefit of the approach proposed is its application in simulation-based research aimed to generate quantitative data of normal and pathological conditions. Based on the model presented, taking into account many essential physiological processes and air transport dynamics, comprehensive and combined studies of the respiratory efficiency can be performed. The impact of physical exercise, precise changes in respiratory tract mechanics and alterations in breathing pattern can be analyzed together with the impact of various changes in alveolar-capillary oxygen diffusion. This may be useful in simulation of effects of many severe medical conditions and increased activity level. PMID:24950449

  2. Noninvasive ventilation in trauma

    PubMed Central

    Karcz, Marcin K; Papadakos, Peter J

    2015-01-01

    Trauma patients are a diverse population with heterogeneous needs for ventilatory support. This requirement depends mainly on the severity of their ventilatory dysfunction, degree of deterioration in gaseous exchange, any associated injuries, and the individual feasibility of potentially using a noninvasive ventilation approach. Noninvasive ventilation may reduce the need to intubate patients with trauma-related hypoxemia. It is well-known that these patients are at increased risk to develop hypoxemic respiratory failure which may or may not be associated with hypercapnia. Hypoxemia in these patients is due to ventilation perfusion mismatching and right to left shunt because of lung contusion, atelectasis, an inability to clear secretions as well as pneumothorax and/or hemothorax, all of which are common in trauma patients. Noninvasive ventilation has been tried in these patients in order to avoid the complications related to endotracheal intubation, mainly ventilator-associated pneumonia. The potential usefulness of noninvasive ventilation in the ventilatory management of trauma patients, though reported in various studies, has not been sufficiently investigated on a large scale. According to the British Thoracic Society guidelines, the indications and efficacy of noninvasive ventilation treatment in respiratory distress induced by trauma have thus far been inconsistent and merely received a low grade recommendation. In this review paper, we analyse and compare the results of various studies in which noninvasive ventilation was applied and discuss the role and efficacy of this ventilator modality in trauma. PMID:25685722

  3. 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

  4. 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

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

    SciTech Connect

    Lavender, J.P. (Royal Postgraduate Medical School, London, England); 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.

  6. Where Is the Imbalance?

    ERIC Educational Resources Information Center

    Chan, John H. F.

    2009-01-01

    For many researchers, the concept of a power imbalance is central to the understanding of bullying, and its presence in the bully-victim relationship is a prerequisite condition that needs to be fulfilled before bullying is deemed to have taken place. Despite the concept's central importance in many definitions of bullying, the nature of the power…

  7. 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.

  8. 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 ...

  9. 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

  10. 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.

  11. Fixed Sagittal Plane Imbalance

    PubMed Central

    Savage, Jason W.; Patel, Alpesh A.

    2014-01-01

    Study Design?Literature review. Objective?To discuss the evaluation and management of fixed sagittal plane imbalance. Methods?A comprehensive literature review was performed on the preoperative evaluation of patients with sagittal plane malalignment, as well as the surgical strategies to address sagittal plane deformity. Results?Sagittal plane imbalance is often caused by de novo scoliosis or iatrogenic flat back deformity. Understanding the etiology and magnitude of sagittal malalignment is crucial in realignment planning. Objective parameters have been developed to guide surgeons in determining how much correction is needed to achieve favorable outcomes. Currently, the goals of surgery are to restore a sagittal vertical axis?imbalance varies according to the etiology, location, and severity of the deformity. Fixed sagittal malalignment often requires complex reconstructive procedures that include osteotomy correction. Reestablishing harmonious spinopelvic alignment is associated with significant improvement in health-related quality-of-life outcome measures and patient satisfaction. PMID:25396111

  12. Lung scan perfusion defects limited to matching pleural effusions: low probability of pulmonary embolism

    Microsoft Academic Search

    Richard A. Bedont; F. L. Datz

    1985-01-01

    Patients with a new pleural effusion are often sent for a ventilation-perfusion scan to exclude a pulmonary embolism. This retrospective study assessed the probability of pulmonary embolism when a pleural effusion and a perfusion defect of similar size are the only significant imaging abnormalities. In 451 reports of patients who were scanned for suspected pulmonary embolism, 53 had perfusion defects

  13. [Diet imbalances and aflatoxicosis].

    PubMed

    Ferrando, R; Henry, N

    1977-01-01

    Generally we know influences of diet's balances or imbalances upon toxicants. Some actions appear with aflatoxins as shown by studies on rat, pig, calf, poultry, turkey and duckling. According to species considered, oral administration of aflatoxins reduces food consummation, Nitrogen balance, respiratory coefficient. Therefore those modifications may be induced by a decrease of foodstuffs ingestion. It has been underlined that hypoproteic diet increases intoxication and diet rich in lipotropic factors decreases it. The greatest number of experiments carried out are concerning vitamins A and D. Authors are recounting their own experimentations upon relationships between Ducklings, aflatoxicosis, retinol consumption and cholecalciferol deficiency. In Duckling, diet deficient in vitamin D increases aflatoxins toxicity. Some relations exist with cytochrome P 450. PMID:350118

  14. 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

  15. 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).

  16. Noninvasive ventilation after intubation and mechanical ventilation

    Microsoft Academic Search

    M. Ferrer; O. Bernadich; S. Nava; A. Torres

    2002-01-01

    Noninvasive ventilation after intubation and mechanical ventilation. M. Ferrer, O. Bernadich, S. Nava, A. Torres. #ERS Journals Ltd 2002. ABSTRACT: Patients with chronic airflow obstruction who are difficult to wean from mechanical ventilation are at increased risk of intubation-associated complications and mortality because of prolonged invasive mechanical ventilation. Noninvasive positive pressure ventilation may revert most of the pathophysiological mechanisms associated

  17. Liquid ventilation

    PubMed Central

    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.

  18. Space Shuttle booster thrust imbalance analysis

    NASA Technical Reports Server (NTRS)

    Bailey, W. R.; Blackwell, D. L.

    1985-01-01

    An analysis of the Shuttle SRM thrust imbalance during the steady-state and tailoff portions of the boost phase of flight are presented. Results from flights STS-1 through STS-13 are included. A statistical analysis of the observed thrust imbalance data is presented. A 3 sigma thrust imbalance history versus time was generated from the observed data and is compared to the vehicle design requirements. The effect on Shuttle thrust imbalance from the use of replacement SRM segments is predicted. Comparisons of observed thrust imbalances with respect to predicted imbalances are presented for the two space shuttle flights which used replacement aft segments (STS-9 and STS-13).

  19. Satellites reveal Antarctic mass imbalance

    Microsoft Academic Search

    A. Shepherd

    2004-01-01

    Satellite radar observations have revealed a widespread mass imbalance in western Antarctica and rapid thinning of ice shelves at the Antarctic Peninsula. The former shows grounded ice retreat in a region previously considered unstable to such events, and the latter illuminates an ongoing debate as to the mechanism through which ice shelves have disintegrated over the past decade. Both measurements

  20. On the Class Imbalance Problem

    Microsoft Academic Search

    Xinjian Guo; Yilong Yin; Cailing Dong; Gongping Yang; Guangtong Zhou

    2008-01-01

    The class imbalance problem has been recognized in many practical domains and a hot topic of machine learning in recent years. In such a problem, almost all the examples are labeled as one class, while far fewer examples are labeled as the other class, usually the more important class. In this case, standard machine learning algorithms tend to be overwhelmed

  1. 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.

  2. FATE OF INHALED NITROGEN DIOXIDE IN ISOLATED PERFUSED RAT LUNG

    EPA Science Inventory

    The fate of inhaled NO2 was studied with isolated perfused rat lungs. The isolated lungs were exposed to 5 ppm NO2 for 90 min at a ventilation rate of 45 ml/min. The NO2 exposure had no adverse effects on the lungs as judged from their weights, glucose uptake, or lactate producti...

  3. Age-Related Dizziness and Imbalance

    MedlinePLUS

    ... receive a 15% discount. Age-related dizziness and imbalance Balance and fall prevention for seniors One of ... to reduce this significant health hazard. Causes of imbalance in older people Balance in walking and standing ...

  4. Simulation investigation of wind turbine imbalance faults

    Microsoft Academic Search

    Xiang Gong; Wei Qiao

    2010-01-01

    This paper investigates the use of simulations to study wind turbine imbalance faults. The dynamics of a model wind turbine generator (WTG) are simulated in a combined environment of TurbSim, FAST (Fatigue, Aerodynamics, Structures, Turbulence), and Simulink in three different scenarios, i.e., normal operating conditions, blade imbalance, and aerodynamic asymmetry. The blade imbalance is simulated by scaling the mass density

  5. 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.

  6. 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.

  7. Earth's energy imbalance and implications

    Microsoft Academic Search

    J. Hansen; M. Sato; P. Kharecha; K. von Schuckmann

    2011-01-01

    Improving observations of ocean heat content show 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 ± 0.15 W m-2 during the 6-year period 2005-2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change. Observed

  8. [Electrolyte imbalance in the elderly].

    PubMed

    Yamada, K; Yoshida, S

    1989-05-01

    Imbalance of water and electrolytes in the elderly was investigated. In the elderly, hyponatremia is the most common electrolyte imbalance disorder and half of the cases with hyponatremia are accompanied by malignancy. It is well known that renal function decreases with ageing, and hyporeninemic hypoaldosteronism, relative AVP unresponsiveness and high level of plasma ANP are observed in the elderly. Therefore, renin-aldosterone system, AVP and ANP as well as renal function of the elderly were studied. AVP response to osmotic stimulus in the elderly increased, indicating that osmostat hypersensitivity existed in the elderly. The response of ANP to hypertonic saline infusion was well preserved. Increase in FENa with decrease in GFR and decreased salt-retaining renal capacity, with low response of the renin-aldosterone system, under low salt intake were observed in the elderly. Therefore, the low response of renin-aldosterone system may be, in part, involved in the pathophysiology. Plasma ANP positively correlated with FENa and the rate of the response of FENa to endogenous ANP was lower in the elderly than in young adults. In addition, the ANP disappearance rate from plasma in the elderly decreased. It was, therefore, suggested that those factors might be, in part, responsible for the increase in plasma ANP level. Accordingly, a high plasma ANP level might be relatively non-contributory to hyponatremia in the elderly. In summary, hyponatremia is the most common disorder of electrolyte imbalance in the elderly.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2529384

  9. [Mechanical ventilation in children

    PubMed

    Carvalho, W B

    1998-07-01

    OBJECTIVE: To make a brief review about mechanical ventilation in Pediatrics.METHODS: Review of the classification of types of mechanical ventilation, characteristics of pression and flow waves and indications for its installation. In a sequential way we discuss the various modes of ventilation (control ventilation, assisted-control ventilation, assisted ventilation, intermittent mandatory ventilation, synchronized intermittent mandatory ventilation, pressure-support ventilation) showing some advantages and disadvantages of using these modes. RESULTS: General rules for mechanical ventilation are presented, considering some specific pathologies in Pediatrics (acute respiratory distress syndrome, bronchopleural fistulae, cranial trauma, cardiac failure, neuromuscular pathology, acute asthma and in patients with acute descompensation of a cronic respiratory failure). CONCLUSIONS: Some limitations of mechanical ventilation and the possible advances in a short period are presented. PMID:14685580

  10. [Patient-ventilator interaction].

    PubMed

    Gürsel, Gül; Aydo?du, Müge

    2009-01-01

    Mechanically ventilated patients interact with ventilator functions at different levels such as triggering of the ventilator, pressurization and cycling from inspiration to expiration. Patient ventilator asynchrony in any one of these phase results in fighting with ventilator, increase in work of breathing and respiratory muscle fatigue. Patient ventilator dyssynchrony occurs when gas delivery from the ventilator does not match with the neural output of the respiratory center. The clinical findings of patient-ventilator asynchrony are; use of accessory respiratory muscle, tachypnea, tachycardia, active expiration, diaphoresis and observation of asynchrony between patient respiratory effort and the ventilator waveforms. Among the patients with dynamic hyperinflation such as chronic obstructive pulmonary disease the most frequent causes of patient-ventilator asynchrony are trigger and expiratory asynchronies. In acute respiratory distress syndrome patient-ventilator asynchrony may develop due to problems in triggering or asynchrony in flow and inspiration-expiration cycle. Patient-ventilator interaction during noninvasive mechanical ventilation may be affected by the type of masks used, ventilator types, ventilation modes and parameters, humidification and sedation. Among the different patient groups it is important to know causes and solutions of patient-ventilator asynchrony problems. By this way patient will adapt ventilator and then dyspnea, ineffective respiratory effort and work of breathing may decrease subsequently. PMID:20037864

  11. Meeting Residential Ventilation Standards

    E-print Network

    LBNL 4591E Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems 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

  12. Energy recovery ventilator

    Microsoft Academic Search

    S. L. Schneider; K. Dravnieks

    1985-01-01

    An energy recovery ventilator adapted to be mounted on a roof and adapted to be connected to the outlet of an exhaust air duct of a building ventilation system and the inlet of an air supply duct of a building ventilation system. The energy recovery ventilator includes a housing having an exhaust air chamber and a supply air chamber separated

  13. CT Myocardial Perfusion Imaging.

    PubMed

    Varga-Szemes, Akos; Meinel, Felix G; De Cecco, Carlo N; Fuller, Stephen R; Bayer, Richard R; Schoepf, U Joseph

    2015-03-01

    OBJECTIVE. CT myocardial perfusion imaging is rapidly becoming an important adjunct to coronary CT angiography for the anatomic and functional assessment of coronary artery disease with a single modality. Existing techniques for CT myocardial perfusion imaging include static techniques, which provide a snapshot of the myocardial blood pool, and dynamic techniques. CONCLUSION. This review provides a systematic overview of the presently available approaches for the assessment of myocardial perfusion at CT, including diagnostic accuracy and limitations. PMID:25714277

  14. 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

  15. 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.

  16. 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).

  17. Computing Thermal Imbalance Forces On Satellites

    NASA Technical Reports Server (NTRS)

    Vigue, Yvonne; Schutz, Robert E.; Sewell, Granville; Abusali, Pothai A. M.

    1994-01-01

    HEAT.PRO computer program calculates imbalance force caused by heating of surfaces of satellite. Calculates thermal imbalance force and determines its effect on orbit of satellite, especially where shadow cast by Earth Causes periodic changes in thermal environment around satellite. Written in FORTRAN 77.

  18. 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.

  19. 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 ...

  20. Good ventilation is important

    E-print Network

    #12;Good ventilation is important Whether you're buying a new home or taking care of the one you're in now, good ventilation is important because it helps pro- tect your health and your home. Good ventilation is as critical to your comfort and safety as a reliable heating system, a smoke alarm, or a dry

  1. 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.

  2. Dynamic Imbalance Would Counter Offcenter Thrust

    NASA Technical Reports Server (NTRS)

    Mccanna, Jason

    1994-01-01

    Dynamic imbalance generated by offcenter thrust on rotating body eliminated by shifting some of mass of body to generate opposing dynamic imbalance. Technique proposed originally for spacecraft including massive crew module connected via long, lightweight intermediate structure to massive engine module, such that artificial gravitation in crew module generated by rotating spacecraft around axis parallel to thrust generated by engine. Also applicable to dynamic balancing of rotating terrestrial equipment to which offcenter forces applied.

  3. Performance of ventilators for noninvasive positive pressure ventilation in children

    E-print Network

    Boyer, Edmond

    1 Performance of ventilators for noninvasive positive pressure ventilation in children Brigitte title: ventilators for noninvasive ventilation Supports and grants: The research of Brigitte Fauroux;2 Abstract The aim of the study was to evaluate the performance characteristics of all the ventilators

  4. 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.

  5. Ventilating the English Channel Tunnel

    SciTech Connect

    Dodge, T.M. (Raxcrest Project Management Ltd., Birmingham (United Kingdom))

    1993-10-01

    This article describes a unique ventilation system design which ensures a supply of fresh air to 95 miles of tunnels under the English Channel. The topics of the article include a description of the tunnel, a description of the equipment cooling and ventilation systems including provisions for heating of the tunnel ventilation air, ventilation system operation, and ventilation control system.

  6. 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.

  7. Effect of Ventilation Strategies on

    E-print Network

    1 Effect of Ventilation Strategies on Residential Ozone Levels Iain S. Walker ventilation used to reduce concentrations of indoor-generated pollutants. When assessing the effect of deliberate ventilation on occupant health one should consider not only

  8. Redox Imbalance and Biochemical Changes in Cancer

    PubMed Central

    Jorgenson, Tonia C.; Zhong, Weixiong; Oberley, Terry D.

    2013-01-01

    For this Perspectives article, we explore a hypothesis involving the possible role of reduction/oxidation (redox) state in cancer. We hypothesize many modifications in cellular macromolecules observed in cancer progression may be caused by redox imbalance. Recent biochemical data suggest human prostate cancer cell lines demonstrate a redox imbalance (oxidizing) compared to benign primary prostate epithelial cells; the degree of oxidation varied with aggressive behavior of each cell line. Our recent data suggest human breast cancer tissues demonstrate a redox imbalance (reducing) compared to benign adjacent breast tissues. Accumulating data summarized in this article suggest redox imbalance may regulate gene expression and alter protein stability by posttranslational modifications, in turn modulating existing cellular programs. Despite significant improvements in cancer therapeutics, resistance occurs, and redox imbalance may play a role in this process. Studies demonstrate some cancer therapeutic agents increase generation of reactive oxygen/nitrogen species and antioxidant enzymes, which may alter total antioxidant capacity, cause cellular adaptation, and result in reduced effectiveness of treatment modalities. Approaches involving modulations of intra- and extracellular redox states in combination with other therapies may lead to new treatment options, especially for patients resistant to standard treatments. PMID:23878188

  9. Ventilator Associated Pneumonia (VAP)

    E-print Network

    Connor, Ed

    Ventilator Associated Pneumonia (VAP) Prevention in a CVSICU ­ A CUSP based framework Ventilator Associated Pneumonia (VAP) is a serious hospital acquired condition that develops within 72 hours- associated pneumonia in intensive care: Impact of implementing a care bundle*. Critical Care Medicine, 39

  10. 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.

  11. Ventilation for humidity control: Measurements in a ventilation test house

    Microsoft Academic Search

    S. L. Palin; D. A. McIntyre; R. E. Edwards

    1996-01-01

    Three ventilation systems were installed in a recently refurbished test house: full house mechanical ventilation with heat recovery (MHVR), passive stack ventilation (PSV) and extract fans in kitchen and bathroom. Humidifiers were installed to simulate normal occupancy and behaviour of the ventilation was monitored over the winter of 1993\\/94. The test house has a low leakage rate of 3 ac

  12. Earth's Energy Imbalance: Confirmation and Implications

    E-print Network

    an indirect but precise quantification of Earth_s energy im- balance. We compare observed ocean heat storageEarth's Energy Imbalance: Confirmation and Implications James Hansen,1,2 * Larissa Nazarenko,1 Tausnev3 Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among

  13. Flywheels Would Compensate for Rotor Imbalance

    NASA Technical Reports Server (NTRS)

    Hrastar, J. A. S.

    1982-01-01

    Spinning flywheels within rotor can null imbalance forces in rotor. Flywheels axes are perpendicular to each other and to rotor axis. Feedback signals from accelerometers or strain gages in platform control flywheel speeds and rotation directions. Concept should be useful for compensating rotating bodies on Earth. For example, may be applied to large industrial centrifuge, particularly if balance changes during operation.

  14. Cryptic telomere imbalance: A 15-year update

    Microsoft Academic Search

    David H. Ledbetter; Christa Lese Martin

    2007-01-01

    It has been 15 years since we proposed that assays of telomere integrity might reveal cryptic translocations and deletions as a significant cause of mental retardation (MR) in patients with normal G-banded karyotypes. Development of unique genomic probes adjacent to the subtelomeric repeats of each chromosome arm allowed multiplex FISH analyses that confirmed such cryptic telomeric imbalances in 3-6% of

  15. Mechanical ventilation after injury.

    PubMed

    Maung, Adrian A; Kaplan, Lewis J

    2014-01-01

    Injury is a major cause of critical illness worldwide. Severely injured patients often require mechanical ventilation not only to manage primary respiratory failure but also as adjunct to manage other conditions. Injury induces fundamental changes in multiple organ systems which directly impact ventilator management; these changes are not shared by patients without concomitant tissue injury. In this article, we review the physiologic changes after injury and discuss the impact of injury on ventilator strategies and management. We also explore the special considerations in patients with traumatic brain injury, thermal injury, blast injury or bronchopleural fistula. PMID:22956744

  16. 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.

  17. 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.

  18. [Ventilator-associated pneumonia].

    PubMed

    Rosseau, S; Schütte, H; Suttorp, N

    2013-08-01

    Ventilator-associated pneumonia (VAP) is a severe, not entirely preventable complication of invasive ventilation. Timely and adequate antibiotic treatment is important; therefore, intensivists often initiate broad spectrum antibiotic regimens upon clinical suspicion of VAP. Criteria for the diagnosis of VAP are not perfect and a clear distinction of VAP from ventilator-associated tracheobronchitis is not always possible due to the limitations of chest x-rays in ventilated patients. The attributable mortality of VAP is likely overestimated. All these aspects increase the need to reevaluate the diagnosis of VAP on a daily basis. Microbiology data are helpful in the decision to de-escalate or stop antibiotics. The prudent use of antibiotics and implementation of a number of preventive measures are key for management of VAP in ICUs. These steps will help to minimize the development of multidrug-resistant pathogens and, in turn, may help guarantee more antibiotic options for future patients. PMID:23836252

  19. 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.

  20. A Century of Vertical Fiscal Imbalance in Australian Federalism

    Microsoft Academic Search

    Brian Dollery

    2002-01-01

    After a century of Australian fiscal federalism, while the problems posed by horizontal fiscal imbalance have largely been resolved, the thorny issue of vertical fiscal imbalance remains. After reviewing the evolution of economic doctrine on fiscal federalism, this paper examines the historical evolution of vertical fiscal imbalance in the light of the views expressed by Australian economists over the past

  1. Earth's Energy Imbalance and Ocean Heat Storage

    NASA Astrophysics Data System (ADS)

    Hansen, J.; Willis, J.; Leuliette, E.; Bleck, R.; Lo, K.; Ruedy, R.; Sato, M.; Sun, S.

    2006-12-01

    The Earth's energy imbalance, i.e., the difference between solar energy absorbed and thermal energy emitted by the planet, is fundamental to global climate change, as it measures the net forcing acting on the climate system. The imbalance is now positive on decadal time scales, due to dominance of increasing greenhouse gas (GHG) forcing, and, with canonical climate sensitivity, it yields an estimate of the amount of global warming that remains "in the pipeline" due to GHGs already in the atmosphere. The ocean is the largest sink for excess incoming energy. Inference of information from the energy imbalance is affected by a trade-off between decreasing accuracy of earlier data and the added information from longer time scales. We use two atmosphere-ocean models, with ocean heat and sea level measurements, to study the roles of different climate forcings, unforced climate variability including ocean- cloud interactions, and limitations of data sampling. We find that observed decrease in ocean heat content in the upper 750m in 2004-2005 does not significantly alter the estimate of ~0.5C global warming still "in the pipeline". Continuation and refinement of measurements of ocean heat, sea level, and ice sheet mass balance have the potential to greatly refine understanding of global warming, its practical implications, and important climate processes, but to be most useful they need to be supplemented by better measurements of deep ocean heat content changes and precise measurements of changing climate forcings such as tropospheric aerosols.

  2. 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 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation...

  3. 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 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation...

  4. 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 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation...

  5. 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 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation...

  6. 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 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111...Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation...

  7. The Global Imbalance of the Inanimate Nature

    NASA Astrophysics Data System (ADS)

    Vargashkin, V. Y.

    2013-12-01

    The preservation laws serve is the general expression of balancing properties and stability in nature. The preservation laws, according to Noether's theorem, are displays of properties of uniformity and isotropy of space and time. So, in the most global representation, the imbalance of the Universe assumes presence of some large-scale non-uniformity in it. The scale of such non-uniformity may form the basis for balance and imbalance correlation in the nature as a whole. This heterogeneity may lead to global infringement of laws of preservation, such as laws of preservation of an impulse, the impulse and the moment of energy. So, the most global imbalance of the inanimate nature may be connected with existence of large-scale fluctuations of properties of the Universe matter. It is possible to think about existence of such imbalance with presence of the allocated areas and directions on celestial sphere. Now most of interest in a science is represented by some types of global anisotropy. First, it is spatial anisotropy of cosmic microwave background. It depends of direction on celestial sphere, including formation of the allocated directions, and also "hot" and "cold" spots. Secondly, it is anisotropy of substance's density, concerning clusters and super clusters of galaxies. It is known as a large-scale structure of the Universe. This kind of anisotropy is connected with imbalance between distributions of radiated substance and observable emptiness. The geometry of this kind of imbalance is that the shining matter forms "cellular", "sheet" or "filaments" structure, forming the cells, filled with visible "voids". Thirdly, it is the hypothetical anisotropy connected with prospective dependence of speed of expansion of the Universe with direction on celestial sphere, and also with time. The relative size for this speed is known as Hubble's parameter. The told testifies about actuality of systematization, and also revelation of an interconnection and mutual conditionality of various kinds of global anisotropy of the Universe. So, astro- and photometric characteristics of various types of remote quasi-stellar objects may be used. Modern catalogues contain more than one million quasars. If the property of quasars on the average is invariable in various directions and during the various moments of time, anisotropy of average luminosity received with the calculations is a consequence of anisotropy of properties of expansion of the Universe. For example, if in any direction average settlement luminosity of quasars is underestimated, it is necessary to considering as consequence of the raised speed of expansion of the Universe in this direction. Thus it is possible to establish both speed, and acceleration of expansion of the Universe in these directions during the various moments of time on the basis of difference in average luminosity of the quasars observed in various directions of the Universe and on various removals from the ground observer. Comparison of the allocated places and directions in the Universe which are found out by means of the analysis of luminosity of quasars, and also distributions of temperature of a cosmic microwave background and distributions of density of system of voids and filaments in large-scale structure of the Universe will allow to think about global correlation of balance and imbalance in the scale of all inanimate nature as a whole.

  8. 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).

  9. 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).

  10. 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 ...

  11. 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...

  12. 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.

  13. Increased chromosomal imbalances in recurrent pituitary adenomas.

    PubMed

    Rickert, C H; Dockhorn-Dworniczak, B; Busch, G; Moskopp, D; Albert, F K; Rama, B; Paulus, W

    2001-12-01

    Eight pituitary adenomas (four gonadotroph cell adenomas, three prolactin cell adenomas, one null cell adenoma) and their respective recurrences in the same patients were studied by comparative genomic hybridization. Chromosomal imbalances were found in seven of eight patients affecting two of eight primary and seven of eight recurrent tumors. Overall, pituitary adenomas showed an average of 1.6 chromosomal imbalances per primary and 3.4 per recurrent tumor (P < 0.01). Prolactin cell adenomas showed an average of 4.3 chromosomal changes per primary and 6.3 per recurrent tumor, which were significantly more common than in gonadotroph cell adenomas (0 vs 1.7 changes; P < 0.05) and the null cell adenoma (0 vs 1.0 changes; P < 0.05). The most common changes were gains of 4q (in three of eight recurrences), 5q, and 13q (in two of eight recurrences each) as well as losses of chromosome 2 (in both primary and recurring tumors of two patients), 1p, 8q, 10, and 12q (in two of eight recurrences). Minimal common regions associated with recurrent adenomas were gains of 4q31.2-34 (three recurrences), 5q14-23 and 13q21-31 and losses of 12q24.3-qter (two recurrences each). The average MIB-1 proliferation indices were 1.2% for primary and 1.9% for recurrent adenomas (P < 0.005). Our findings suggest that acquisition of certain chromosomal imbalances is related to and may underlie adenoma recurrence. PMID:11761722

  14. 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

  15. 3, 805826, 2006 Ventilation under

    E-print Network

    Paris-Sud XI, Université de

    OSD 3, 805­826, 2006 Ventilation under global warming A. Gnanadesikan et al. Title Page Abstract ocean ventilation change under global warming? A. Gnanadesikan 1 , J. L. Russell 2 , and F. Zeng 3 1­826, 2006 Ventilation under global warming A. Gnanadesikan et al. Title Page Abstract Introduction

  16. The International Journal of Ventilation

    E-print Network

    California at Davis, University of

    The International Journal of Ventilation Volume 12 Number 4 ISSN 1473 - 3315 March 2014 Contents A and Mróz T 391 #12;International Journal of Ventilation ISSN 1473-3315 Volume 12 No 4 March 2014 air quality and reducing energy required for heating, cooling, and ventilation. One application

  17. Alterations in expression of elastogenic and angiogenic genes by different conditions of mechanical ventilation in newborn rat lung.

    PubMed

    Kroon, Andreas A; Wang, Jinxia; Post, Martin

    2015-04-01

    Mechanical ventilation is an important risk factor for development of bronchopulmonary dysplasia. Here we investigated the effects of different tidal volumes (VT) and duration of ventilation on expression of genes involved in alveolarization [tropoelastin (Eln), lysyloxidase-like 1 (Loxl1), fibulin5 (Fbln5), and tenascin-C (Tnc)] and angiogenesis [platelet derived growth factors (Pdgf) and vascular endothelial growth factors (Vegf) and their receptors] in 8-day-old rats. First, pups were ventilated for 8 h with low (LVT: 3.5 ml/kg), moderate (MVT: 8.5 ml/kg), or high (HVT: 25 ml/kg) tidal volumes. LVT and MVT decreased Tnc expression, whereas HVT increased expression of all three elastogenic genes and Tnc. PDGF ?-receptor mRNA was increased in all ventilation groups, while Pdgfb expression was decreased after MVT and HVT ventilation. Only HVT ventilation upregulated Vegf expression. Independent of VT, ventilation upregulated Vegfr1 expression, while MVT and HVT downregulated Vegfr2 expression. Next, we evaluated duration (0-24 h) of MVT ventilation on gene expression. Although expression of all elastogenic genes peaked at 12 h of ventilation, only Fbln5 was negatively affected at 24 h. Tnc expression decreased with duration of ventilation. Changes in expression of Pdgfr and Vegfr were maximal at 8 h of ventilation. Disturbed elastin fiber deposition and decrease in small vessel density was only observed after 24 h. Thus, an imbalance between Fbln5 and Eln expression may trigger dysregulated elastin fiber deposition during the first 24 h of mechanical ventilation. Furthermore, ventilation-induced alterations in Pdgf and Vegf receptor expression are tidal volume dependent and may affect pulmonary vessel formation. PMID:25617376

  18. 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.

  19. 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.

  20. 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 ...

  1. L. Slimani / Quantification of liver perfusion with PET 1 Quantification of liver perfusion with [15

    E-print Network

    Paris-Sud XI, Université de

    L. Slimani / Quantification of liver perfusion with PET 1 Quantification of liver perfusion. Running Title : Quantification of liver perfusion with PET Corresponding authors: Patricia Iozzo, MD, Ph of liver perfusion with PET 2 Abstract (204 words) Background/Aims: Hepatic perfusion plays an important

  2. Agronomic phosphorus imbalances across the world's croplands

    PubMed Central

    MacDonald, Graham K.; Bennett, Elena M.; Potter, Philip A.; Ramankutty, Navin

    2011-01-01

    Increased phosphorus (P) fertilizer use and livestock production has fundamentally altered the global P cycle. We calculated spatially explicit P balances for cropland soils at 0.5° resolution based on the principal agronomic P inputs and outputs associated with production of 123 crops globally for the year 2000. Although agronomic inputs of P fertilizer (14.2 Tg of P·y?1) and manure (9.6 Tg of P·y?1) collectively exceeded P removal by harvested crops (12.3 Tg of P·y?1) at the global scale, P deficits covered almost 30% of the global cropland area. There was massive variation in the magnitudes of these P imbalances across most regions, particularly Europe and South America. High P fertilizer application relative to crop P use resulted in a greater proportion of the intense P surpluses (>13 kg of P·ha?1·y?1) globally than manure P application. High P fertilizer application was also typically associated with areas of relatively low P-use efficiency. Although manure was an important driver of P surpluses in some locations with high livestock densities, P deficits were common in areas producing forage crops used as livestock feed. Resolving agronomic P imbalances may be possible with more efficient use of P fertilizers and more effective recycling of manure P. Such reforms are needed to increase global agricultural productivity while maintaining or improving freshwater quality. PMID:21282605

  3. Perfusion Measurement in Acute Pancreatitis Using Dynamic Perfusion MDCT

    Microsoft Academic Search

    Pierre E. Bize; Alexandra Platon; Christoph D. Becker; Pierre-Alexandre Poletti

    OBJECTIVE. Our objective was to determine whether MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis in the initial phase of the disease. One hundred six patients with abdominal pain were prospectively enrolled in this study. CONCLUSION. Patients were separated into two groups: P1 (severe) and P2 (mild) acute pancreatitis. Mean perfusion value was 24.8 mL\\/100

  4. 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.

  5. Vascular release of nonheme iron in perfused rabbit lungs.

    PubMed

    Huang, Y T; Ghio, A J; Nozik-Grayck, E; Piantadosi, C A

    2001-03-01

    In this study, we hypothesized that the lung actively releases excess iron into the circulation to regulate iron homeostasis. We measured nonheme iron (NHFe) in the perfusate of control isolated perfused rabbit lungs and lungs with ischemia-reperfusion (I/R) ventilated with normoxic (21% O(2)) or hypoxic (95% N(2)) gas mixtures. Some were perfused with bicarbonate-free (HEPES) buffer or treated with the anion exchange inhibitor DIDS. The control lungs released approximately 0.25 microg/ml of NHFe or 20% of the total lung NHFe into the vascular space that was not complexed with ferritin, transferrin, or lactoferrin or bleomycin reactive. The I/R lungs released a similar amount of NHFe during ischemia and some bleomycin-detectable iron during reperfusion. NHFe release was attenuated by approximately 50% in both control and ischemic lungs by hypoxia and by >90% in control lungs and approximately 60% in ischemic lungs by DIDS and HEPES. Reperfusion injury was not affected by DIDS or HEPES but was attenuated by hypoxia. These results indicate that biologically nonreactive nonheme iron is released rapidly by the lung into the vascular space via mechanisms that are linked to bicarbonate exchange. During prolonged ischemia, redox-active iron is also released into the vascular compartment by other mechanisms and may contribute to lung injury. PMID:11159031

  6. Ocular perfusion pressure in glaucoma.

    PubMed

    Costa, Vital P; Harris, Alon; Anderson, Douglas; Stodtmeister, Richard; Cremasco, Fernanda; Kergoat, Helene; Lovasik, John; Stalmans, Ingborg; Zeitz, Oliver; Lanzl, Ines; Gugleta, Konstantin; Schmetterer, Leopold

    2014-06-01

    This review article discusses the relationship between ocular perfusion pressure and glaucoma, including its definition, factors that influence its calculation and epidemiological studies investigating the influence of ocular perfusion pressure on the prevalence, incidence and progression of glaucoma. We also list the possible mechanisms behind this association, and discuss whether it is secondary to changes in intraocular pressure, blood pressure or both. Finally, we describe the circadian variation of ocular perfusion pressure and the effects of systemic and topical medications on it. We believe that the balance between IOP and BP, influenced by the autoregulatory capacity of the eye, is part of what determines whether an individual will develop optic nerve damage. However, prospective, longitudinal studies are needed to better define the role of ocular perfusion pressure in the development and progression of glaucoma. PMID:24238296

  7. 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.

  8. Electric Fields in Perfused Nerves

    Microsoft Academic Search

    L. Bass; W. J. Moore

    1967-01-01

    IN perfusion experiments with squid giant axons, the internal potassium concentration Ki can be reduced either by substitution of other univalent ions, so that both ionic strength si and osmolality are kept constant, or by dilution with non-electrolytes at constant osmolality. The importance of non-electrolyte perfusion in testing various models of resting potential difference (p.d.) and action potential is emphasized

  9. 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

  10. Clinical Impact of Proximal Autosomal Imbalances

    PubMed Central

    Hamid, AB; Weise, A; Voigt, M; Bucksch, M; Kosyakova, N; Liehr, T; Klein, E

    2012-01-01

    Centromere-near gain of copy number can be induced by intra- or inter-chromosomal rearrangements or by the presence of a small supernumerary marker chromosome (sSMC). Interestingly, partial trisomy to hexasomy of euchromatic material may be present in clinically healthy or affected individuals, depending on origin and size of chromosomal material involved. Here we report the known minimal sizes of all centromere-near, i.e., proximal auto-somal regions in humans, which are tolerated; over 100 Mb of coding DNA are comprised in these regions. Additionally, we have summarized the typical symptoms for nine proximal autosomal regions including genes obviously sensitive to copy numbers. Overall, studying the carriers of specific chromosomal imbalances using genomics-based medicine, combined with single cell analysis can provide the genotype-phenotype correlations and can also give hints where copy-number-sensitive genes are located in the human genome. PMID:24052727

  11. CAD of myocardial perfusion

    NASA Astrophysics Data System (ADS)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2007-03-01

    Our purpose is in the automated evaluation of the physiological relevance of lesions in coronary angiograms. We aim to extract as much as possible quantitative information about the physiological condition of the heart from standard angiographic image sequences. Coronary angiography is still the gold standard for evaluating and diagnosing coronary abnormalities as it is able to locate precisely the coronary artery lesions. The dimensions of the stenosis can be assessed nowadays successfully with image processing based Quantitative Coronary Angiography (QCA) techniques. Our purpose is to assess the clinical relevance of the pertinent stenosis. We therefore analyze the myocardial perfusion as revealed in standard angiographic image sequences. In a Region-of-Interest (ROI) on the angiogram (without an overlaying major blood vessel) the contrast is measured as a function of time (the so-called time-density curve). The required hyperemic state of exercise is induced artificially by the injection of a vasodilator drug e.g. papaverine. In order to minimize motion artifacts we select based on the recorded ECG signal end-diastolic images in both a basal and a hyperemic run in the same projection to position the ROI. We present the development of the algorithms together with results of a small study of 20 patients which have been catheterized following the standard protocol.

  12. MR Perfusion Imaging in Acute Ischemic Stroke

    PubMed Central

    Copen, William A.; Schaefer, Pamela W.; Wu, Ona

    2011-01-01

    MR perfusion imaging offers the potential for measuring brain perfusion in acute stroke patients, at a time when treatment decisions based upon these measurements may affect outcomes dramatically. Rapid advancements in both acute stroke therapy and perfusion imaging techniques have resulted in continuing redefinition of the role that perfusion imaging should play in patient management. This review first discusses the basic pathophysiology of acute stroke, with specific attention to alterations in the various perfusion-related parameters that can be studied by MR perfusion imaging. Although these parameters are sometimes treated as somewhat interchangeable, they reveal greatly different information about brain perfusion. Therefore, subsequent discussion of the utility of different kinds of perfusion images focuses on the differences between them, as well as important artifacts that can complicate their interpretation. Finally, research on the continually evolving role of MR perfusion imaging in acute stroke care is summarized. PMID:21640299

  13. 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.

  14. Lightweight ventilated facade prototype: acoustic performance evaluation when the ventilation surface of

    E-print Network

    Boyer, Edmond

    Lightweight ventilated facade prototype: acoustic performance evaluation when the ventilation Conference 23-27 April 2012, Nantes, France 3801 #12;1. INTRODUCTION Lightweight ventilated facades cavity is almost totally open, fully ventilated and not very wide. Therefore, its contribution

  15. A Central Dilemma in the Mental Health Sector: Structural Imbalance

    ERIC Educational Resources Information Center

    Doessel, Darrel P.; Williams, Ruth F. G.; Nolan, Patricia

    2008-01-01

    Mental health services provision is persistently criticised regarding resource inadequacy. Services are also subject to another dilemma, "structural imbalance". This study demonstrates the dimensions of structural imbalance in Australia's mental health sector by recourse to the 1997 Australian Bureau of Statistics national survey of mental health…

  16. THE ROLE OF IONORGANIC ION IMBALANCE IN AQUATIC TOXICITY TESTING

    EPA Science Inventory

    This paper assessess the issue of ion imbalance, provides summary of applicable data, presents several successful technical tools to address toxicity resulting from salinity and ion imbalances, and discusses regulatory/compliance options to manage discharges with salinity/ion imb...

  17. Where Are the Boys? Gender Imbalance in Higher Education

    ERIC Educational Resources Information Center

    Evers, Fred; Livernois, John; Mancuso, Maureen

    2006-01-01

    The gender breakdown in higher education in Canada and other western countries has switched from an imbalance in favour of men to an imbalance in favour of women over the last two decades. Programs to attract women into higher education have worked very well. At the University of Guelph for example, 70% of the students are women. Should educators…

  18. 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…

  19. 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.

  20. Pulmonary perfusion heterogeneity is increased by sustained, heavy exercise in humans.

    PubMed

    Burnham, K J; Arai, T J; Dubowitz, D J; Henderson, A C; Holverda, S; Buxton, R B; Prisk, G K; Hopkins, S R

    2009-11-01

    Exercise presents a considerable stress to the pulmonary system and ventilation-perfusion (Va/Q) heterogeneity increases with exercise, affecting the efficiency of gas exchange. In particular, prolonged heavy exercise and maximal exercise are known to increase Va/Q heterogeneity and these changes persist into recovery. We hypothesized that the spatial heterogeneity of pulmonary perfusion would be similarly elevated after prolonged exercise. To test this, athletic subjects (n = 6, Vo(2max) = 61 ml. kg(-1).min(-1)) with exercising Va/Q heterogeneity previously characterized by the multiple inert gas elimination technique (MIGET), performed 45 min of cycle exercise at approximately 70% Vo(2max). MRI arterial spin labeling measures of pulmonary perfusion were acquired pre- and postexercise (at 20, 40, 60 min post) to quantify the spatial distribution in isogravitational (coronal) and gravitationally dependent (sagittal) planes. Regional proton density measurements allowed perfusion to be normalized for density and quantified in milliliters per minute per gram. Mean lung density did not change significantly in either plane after exercise (P = 0.19). Density-normalized perfusion increased in the sagittal plane postexercise (P =or <0.01) but heterogeneity did not (all P >or= 0.18), likely because of perfusion redistribution and vascular recruitment. Density-normalized perfusion was unchanged in the coronal plane postexercise (P = 0.66), however, perfusion heterogeneity was significantly increased as measured by the relative dispersion [RD, pre 0.62(0.07), post 0.82(0.21), P < 0.0001] and geometric standard deviation [GSD, pre 1.74(0.14), post 2.30(0.56), P < 0.005]. These changes in heterogeneity were related to the exercise-induced changes of the log standard deviation of the ventilation distribution, an MIGET index of Va/Q heterogeneity (RD R(2) = 0.68, P < 0.05, GSD, R(2) = 0.55, P = 0.09). These data are consistent with but not proof of interstitial pulmonary edema as the mechanism underlying exercise-induced increases in both spatial perfusion heterogeneity and Va/Q heterogeneity. PMID:19745192

  1. Pulmonary complications of mechanical ventilation.

    PubMed

    Sandur, S; Stoller, J K

    1999-06-01

    Although life-saving, mechanical ventilation may be associated with many complications, including consequences of positive intrathoracic pressure, the many aspects of volutrauma, and adverse effects of intubation and tracheostomy. Optimal ventilatory care requires implementing mechanical ventilation with attention to minimizing adverse hemodynamic effects, averting volutrauma, and effecting freedom from mechanical ventilation as quickly as possible so as to minimize the risk of airway complications. PMID:10386254

  2. Assessment of regional ventilation by continuous inhalation of radioactive krypton-81m

    Microsoft Academic Search

    F Fazio; T Jones

    1975-01-01

    A simple technique is described for producing high-quality functional images of regional ventilation during physiological tidal breathing of the inert gas 81mKr. These images are quickly obtained on a gamma-camera without the need of computerized systems for data acquisition and display and are directly comparable with those of perfusion obtained with 99mTc-labelled macroaggregates. The short time required for the procedure,

  3. ATP-independent Membrane Depolarization with Ischemia in the Oxygen-ventilated Isolated Rat Lung

    Microsoft Academic Search

    Abu B. Al-Mehdi; Guochang Zhao; Aron B. Fisher

    1998-01-01

    We hypothesize that lung ischemic injury is related to cessation of flow leading to endothelial cell mem- brane depolarization and activation of oxidant-generating systems. Cell membrane potential was assessed in isolated, oxygen ventilated, Krebs-Ringer bicarbonate buffer-dextran-perfused rat lungs by lung surface fluorescence after infusion of bis-oxonol or 5,5 9 ,6,6 9 -tetrachloro-1,1 9 ,3,3 9 -tetraethylbenzimidazolyl-car- bocyanine iodide (JC-1), voltage-sensitive

  4. Laboratory Ventilation SafetyLaboratory Ventilation Safety J. Scott WardJ. Scott Ward

    E-print Network

    Farritor, Shane

    Laboratory Ventilation SafetyLaboratory Ventilation Safety J. Scott WardJ. Scott Ward #12;In 1925. Labconco CorporationLabconco Corporation #12;Laboratory VentilationLaboratory Ventilation #12;Laboratory Ventilation ProductsLaboratory Ventilation Products #12;History of Fume HoodsHistory of Fume Hoods Thomas

  5. Ventilated oscillatory boundary layers

    NASA Astrophysics Data System (ADS)

    Conley, Daniel C.; Inman, Douglas L.

    1993-02-01

    A combination of field and laboratory experiments are made in order to expand our knowledge of naturally occurring oscillatory boundary layers. Chapter 1 describes field observations of the development of wave driven boundary layers at the fluid sediment interface. Under the crest of the wave, this development can be idealized as an identifiable sequence of three parts. The latter parts of this development are never observed to occur under the trough of the wave despite similarities in wave orbital velocity and acceleration. It is proposed that wave induced boundary ventilation, the oscillatory flow through the surface of a permeable bed, may be responsible for this apparent developmental asymmetry. In chapter 2, a laboratory study is presented of ventilated oscillatory boundary layers. These are boundary layers arising from a flow which oscillates parallel to a permeable bed which is subject to oscillating percolation of the same frequency as the bed parallel flow. Measurements of boundary layer velocities, bed stress and turbulent flow properties are presented. It is observed that suction (flow into the bed) enhances the near bed velocities and bed stress while injection (flow out of the bed) leads to a reduction in these quantities. As the ventilated oscillatory boundary layer experiences both these phenomena in one full cycle, the result is a net stress and a net boundary layer velocity in an otherwise symmetric flow. While production of turbulence attributable to injection is enhanced, the finite time required for this to occur leads to greater vertically averaged turbulence in the suction half cycle. Turbulence generated in the suction half cycle is maintained in a compact layer much closer to the bed. These effects appear to hold for Re ranging from 10(exp 5) to 10(exp 6) and for oscillations other than sinusoidal.

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. JAMA Patient Page: Ventilator-Associated Pneumonia

    MedlinePLUS

    ... a person who is being assisted by mechanical ventilation (a breathing machine), is a serious and life- ... associated pneumonia are already critically ill (requiring mechanical ventilation), the death rate from ventilator-associated pneumonia is ...

  16. 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...

  17. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 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...

  18. Air Distribution Effectiveness for Different Mechanical Ventilation

    E-print Network

    LBNL-62700 Air Distribution Effectiveness for Different Mechanical Ventilation Systems Max H Effectiveness for Different Mechanical Ventilation Systems Max H. Sherman and Iain S. Walker Lawrence Berkeley National Laboratory, USA ABSTRACT The purpose of ventilation is to dilute indoor contaminants

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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.

  14. 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)

  15. 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 ...

  16. Proximate Sources of Population Sex Imbalance in India

    PubMed Central

    OSTER, EMILY

    2009-01-01

    There is a population sex imbalance in India. Despite a consensus that this imbalance is due to excess female mortality, the specific source of this excess mortality remains poorly understood. I use microdata on child survival in India to analyze the proximate sources of the sex imbalance. I address two questions: when in life does the sex imbalance arise, and what health or nutritional investments are specifically responsible for its appearance? I present a new methodology that uses microdata on child survival. This methodology explicitly takes into account both the possibility of naturally occurring sex differences in survival and possible differences between investments in their importance for survival. Consistent with existing literature, I find significant excess female mortality in childhood, particularly between the ages of 1 and 5, and argue that the sex imbalance that exists by age 5 is large enough to explain virtually the entire imbalance in the population. Within this age group, sex differences in vaccinations explain between 20% and 30% of excess female mortality, malnutrition explains an additional 20%, and differences in treatment for illness play a smaller role. Together, these investments account for approximately 50% of the sex imbalance in mortality in India. PMID:21305396

  17. Hamstrings strength imbalance in professional football (soccer) players in australia.

    PubMed

    Ardern, Clare L; Pizzari, Tania; Wollin, Martin R; Webster, Kate E

    2015-04-01

    Ardern, CL, Pizzari, T, Wollin, MR, and Webster, KE. Hamstrings strength imbalance in professional football (soccer) players in Australia. J Strength Cond Res 29(4): 997-1002, 2015-The aim of this study was to describe the isokinetic thigh muscle strength profile of professional male football players in Australia. Concentric (60° and 240°·s) and eccentric (30° and 120°·s) hamstrings and quadriceps isokinetic strength was measured with a HUMAC NORM dynamometer. The primary variables were bilateral concentric and eccentric hamstring and quadriceps peak torque ratios, concentric hamstring-quadriceps peak torque ratios, and mixed ratios (eccentric hamstring 30°·s ÷ concentric quadriceps 240°·s). Hamstring strength imbalance was defined as deficits in any 2 of: bilateral concentric hamstring peak torque ratio <0.86, bilateral eccentric hamstring peak torque ratio <0.86, concentric hamstring-quadriceps ratio <0.47, and mixed ratio <0.80. Fifty-five strength tests involving 42 players were conducted. Ten players (24%) were identified as having hamstring strength imbalance. Athletes with strength imbalance had significantly reduced concentric and eccentric bilateral hamstring peak torque ratios at all angular velocities tested; and reduced eccentric quadriceps peak torque (30°·s) in their stance leg, compared with those without strength imbalance. Approximately, 1 in 4 players had preseason hamstring strength imbalance; and all strength deficits were observed in the stance leg. Concentric and eccentric hamstrings strength imbalance may impact in-season football performance and could have implications for the future risk of injury. PMID:25426513

  18. Nutritional imbalance endorsed by televised food advertisements.

    PubMed

    Mink, Michael; Evans, Alexandra; Moore, Charity G; Calderon, Kristine S; Deger, Shannon

    2010-06-01

    The ubiquity of television in American culture makes it a potential contributor to the obesogenic (obesity-causing) environment. Televised food advertisements, which encourage viewers to eat the foods promoted for sale, constitute a de facto set of dietary endorsements. The purpose of this study was to compare the nutritional content of food choices endorsed on television to nutritional guidelines. Using a cross-sectional design, food advertisements were observed during 84 hours of primetime and 12 hours of Saturday-morning televised broadcast during the fall of 2004. One-sample t tests were used to compare the food group servings of observed food items to the recommended daily servings and to compare the nutrient content of observed food items to the Daily Values. Results suggest that a diet consisting of observed food items would provide 2,560% of the recommended daily servings for sugars, 2,080% of the recommended daily servings for fat, 40% of the recommended daily servings for vegetables, 32% of the recommended daily servings for dairy, and 27% of the recommended daily servings for fruits. The same diet would substantially oversupply protein, total fat, saturated fat, cholesterol, and sodium, while substantially undersupplying carbohydrates, fiber, vitamins A, E, and D, pantothenic acid, iron, phosphorous, calcium, magnesium, copper, and potassium. Overall, the food choices endorsed on television fail to meet nutrition guidelines and encourage nutritional imbalance. PMID:20497780

  19. Redox Imbalance in Parkinson’s Disease

    PubMed Central

    Chinta, Shankar J.; Andersen, Julie K.

    2008-01-01

    Parkinson’s disease (PD) is an adult-onset neurodegenerative disorder characterized by preferential loss of dopaminergic neurons in an area of the midbrain called the substantia nigra (SN) along with occurrence of intraneuronal inclusions called Lewy bodies. The majority of cases of PD are sporadic in nature with late onset (95% of patients); however a few PD cases (5%) are seen in familial clusters with generally earlier onset. Although PD has been heavily researched, so far the exact cause of the rather selective cell death is unknown. Multiple lines of evidence suggest an important role for oxidative stress. Dopaminergic neurons (DA) are particularly prone to oxidative stress due to DA metabolism and auto-oxidation combined with increased iron, decreased total glutathione levels and mitochondrial complex I inhibition-induced ROS production in the SN which can lead to cell death by exceeding the oxidative capacity of DA-containing cells in the region. Enhancing antioxidant capabilities and chelating labile iron pools in this region therefore constitutes a rational approach to prevent or slow ongoing damage of DA neurons. In this review, we summarize the various sources of reactive oxygen species that may cause redox imbalance in PD as well as potential therapeutic targets for attenuation of oxidative stress associated with PD. PMID:18358848

  20. 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.

  1. Nocturnal noninvasive ventilation.

    PubMed

    Ozsancak, Aylin; D'Ambrosio, Carolyn; Hill, Nicholas S

    2008-05-01

    Nocturnal noninvasive ventilation (NNV), the provision of ventilatory assistance via a noninvasive interface mainly during sleep, has assumed an important role in the management of chronic hypoventilatory syndromes. This review focuses on recent developments related to the use of NNV to treat various forms of chronic respiratory failure or insufficiency. In the past, NNV has been used mainly to treat respiratory insufficiency in patients with neuromuscular disease (NMD) or chest wall deformity; it should be instituted when these patients have orthopnea or daytime symptoms associated with nocturnal hypoventilation. An emerging application is to treat obesity-hypoventilation syndrome, particularly in continuous positive airway pressure (CPAP) failures. Additionally, it has a role in managing some patients with obstructive sleep apnea who are hypoventilating or find the lower expiratory pressure with bilevel positive pressure ventilators more tolerable than with CPAP alone. NNV to treat severe, stable COPD remains controversial, although a subgroup of patients with hypercapnea and sleep-disordered breathing (SDB) seems most likely to respond favorably. NNV to treat central SDB in patients with congestive heart failure continues to be investigated. Recent findings from a Canadian CPAP trial were disappointing, but preliminary results on a novel adaptive NNV mode are promising. PMID:18460530

  2. 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

  3. Intracellular Perfusion of Chilean Giant Squid Axons

    Microsoft Academic Search

    Ichiji Tasaki; Mario Luxoro

    1964-01-01

    Axons of the Chilean giant squid were subjected to continuous intracellular perfusion with either potassium- or sodium-rich salt solutions. In axons immersed in natural sea water and internally perfused with potassium glutamate solution, action potentials which exceeded 160 millivolts were often observed. The resting potential did not vary appreciably with the internal concentration of potassium glutamate. With perfusing solutions containing

  4. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A ventilation system must not recycle vapors from ventilation discharges. (c) Except for the space served by the ventilation duct, a ventilation duct...

  5. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Face ventilation control devices. 75.330...COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall be...

  6. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Face ventilation control devices. 75.330...COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall be...

  7. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Face ventilation control devices. 75.330...COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall be...

  8. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Face ventilation control devices. 75.330...COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall be...

  9. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Face ventilation control devices. 75.330...COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall be...

  10. Myocardial perfusion scintigraphy: the evidence

    Microsoft Academic Search

    S. R. Underwood; C. Anagnostopoulos; M. Cerqueira; P. J. Ell; E. J. Flint; M. Harbinson; A. D. Kelion; A. Al-Mohammad; E. M. Prvulovich; L. J. Shaw; A. C. Tweddel

    2004-01-01

    This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the

  11. Imbalance on a Baroclinically Unstable Interior Front

    NASA Astrophysics Data System (ADS)

    Nadiga, B. T.

    2013-12-01

    In rotating stratified flows of atmospheric and oceanic relevance, the balanced nature of turbulence at scales comparable to the Rossby deformation radius leads to a confinement of energy at the large scales---scales at which eddy and turbulent dissipative processes are ineffective. In the oceanic context, given that ocean circulation is forced mostly at the large scales, a fundamental question regarding the energetics of ocean circulation is as to how the ocean equilibrates. The forward energy cascade of small-scale, three dimensional turbulence is in contrast to the inverse cascade of energy that is characteristic of the above quasi-two-dimensional balanced turbulence. Consequently, the scales and phenomena that span these two asymptotic regimes of turbulence and the interactions of the flow with boundaries are expected to hold the answer to the ocean-equilibration question. In this context, a great amount of research effort in the recent past has focussed on surface and bottom boundary related processes. However, the bulk of the balanced energy resides in the vertical interior and there is the alternative (spatially) more local route to dissipation directly through the interior turbulent cascade (e.g., as pointed out in Molemaker et al., 2005). We study processes and phenomenology associated with such interior turbulent cascades by considering setups that span the range of scales from the deformation radius to scales where imbalance is possible. However, the nature of the turbulent cascades themselves determine as to whether the smaller of the resolved scales can effectively break balance and provide a route that dissipates balanced energy. Are any of the small scales imbalanced---i.e., are they effective in cascading energy down to small scales?

  12. Lateral imbalance detection on a UAV based on multiple models

    Microsoft Academic Search

    Sajjad Fekri; Da-Wei Gu; Ian Postlethwaite

    2009-01-01

    This paper addresses a multiple-model based lateral imbalance detection methodology for an uninhabited air vehicle (UAV). Two critical imbalance failures are considered that are the failure-induced left aileron stuck and the centre-of-gravity shift along the y-axis. A bank of LTI Kalman filters are designed to detect the above lateral failures and a flight control law based on the model predictive

  13. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III [Hospital of the Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. Anesthesia; Hoffman, E.A. [Univ. of Iowa College of Medicine, Iowa City, IA (United States). Div. of Physiologic Imaging

    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.

  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. Regional coronary perfusion and bioenergetics in experimental atherosclerosis.

    PubMed Central

    Zwolak, R. M.; Malik, A. B.; Morrison, E. S.; Scott, R. F.

    1980-01-01

    The effects of experimental coronary atherosclerosis on myocardial high energy phosphates and regional coronary perfusion and oxygen delivery were studied. Hypercholesterolemic (HC) New Zealand white rabbits developed mild to moderate coronary vascular disease in 4 months when serum cholesterol levels were maintained at 1500--2000 mg/dl. Resting left ventricular levels of creatine phosphate, adenosine triphosphate (ATP), and the cellular energy charge were unaltered after 2 months of diet but were decreased after 4 and 6 months. Tissue lactate and the lactate/pyruvate ratio were increased after 4 months, suggesting mild tissue ischemia. The regional blood flow rate was measured in rabbits given pentobarbital after 6 months of diet using labeled microspheres, and the response to stress was tested after 5 minutes of hypoxic ventilation (5% O2/N2). The percentage of cardiac output to subendocardium (endo) and subepicardium (epi) in HC rabbits and that in control animals were similar at rest, but unlike that of control animals, the endo perfusion did not increase significantly in HC animals during hypoxic stress. Baseline regional left ventricular oxygen deliveries were similar between groups, but the baseline endo/epi oxygen delivery ratio was reduced in HC rabbits. In control rabbits hypoxia did not alter total O2 delivery, and the endo/epi oxygen delivery ratio was constant, whereas hypoxia in HC animals produced a decrease in total oxygen delivery and a further decrease in the endo/epi oxygen delivery ratio. Thus, moderate long-term coronary occlusive disease produced alterations in the distribution of coronary perfusion that are similar to those after acute partial occlusion, ie, selective reductions in blood flow and oxygen delivery to subendocardium. These results may relate to the pathogenesis of subendocardial infarction in man, which often occurs in the absence of complete coronary occlusion. Images Figure 1 PMID:7361855

  16. 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...

  17. 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...

  18. Laboratory Ventilation Management Ralph Stuart, CHO

    E-print Network

    Pawlowski, Wojtek

    Laboratory Ventilation Management Program Ralph Stuart, CHO Ellen Sweet, Laboratory Ventilation Specialist Cornell Department of Environmental Health and Safety 3/29/2013 #12;Laboratory Ventilation.1.2 Design and Construction Standards 10 7.1.3 Carbon Dioxide Ventilation Effectiveness Protocol 10 7.2 Job

  19. Ventilation Based on ASHRAE 62.2

    E-print Network

    Indoor Ventilation Based on ASHRAE 62.2 Arnold Schwarzenegger Governor California Energy Commission Ventilation (ASHRAE 62.2) Minimum Best Practices Guide - Exhaust-Only Ventilation Introduction: The California/ASHRAE Standard 62.2-2007, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings (ASHRAE

  20. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation. 111.15-10 Section 111.15-10...and Installation § 111.15-10 Ventilation. (a) General. Each room...accumulation of flammable gas. (b) Power ventilation. If power ventilation is...

  1. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation. 111.15-10 Section 111.15-10...and Installation § 111.15-10 Ventilation. (a) General. Each room...accumulation of flammable gas. (b) Power ventilation. If power ventilation is...

  2. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation. 111.15-10 Section 111.15-10...and Installation § 111.15-10 Ventilation. (a) General. Each room...accumulation of flammable gas. (b) Power ventilation. If power ventilation is...

  3. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation. 111.15-10 Section 111.15-10...and Installation § 111.15-10 Ventilation. (a) General. Each room...accumulation of flammable gas. (b) Power ventilation. If power ventilation is...

  4. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation. 111.15-10 Section 111.15-10...and Installation § 111.15-10 Ventilation. (a) General. Each room...accumulation of flammable gas. (b) Power ventilation. If power ventilation is...

  5. Humidity as a Control Parameter for Ventilation

    Microsoft Academic Search

    Alireza Afshari; Niels C. Bergsøe

    2003-01-01

    The objective of this study was to develop energy efficient ventilation strategies that will provide both a healthy and comfortable indoor climate and reduce energy consumption compared to present ventilation standards. Humidity was used as a control parameter for the ventilation. Four different ventilation strategies were tested in a test apartment. The results of the experiments indicated that humidity can

  6. 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

  7. 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.

  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. JAMA Patient Page: Mechanical Ventilation

    MedlinePLUS

    ... ventilators , is used routinely when persons have general anesthesia (unconsciousness) for operations, for critically ill individuals who ... sedative medications, or, in the case of general anesthesia, after medications are given to produce unconsciousness to ...

  10. Literature Review of Displacement Ventilation

    E-print Network

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

    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. 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.

  12. 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.

  13. Animal models of ex vivo lung perfusion as a platform for transplantation research

    PubMed Central

    Nelson, Kevin; Bobba, Christopher; Ghadiali, Samir; Jr, Don Hayes; Black, Sylvester M; Whitson, Bryan A

    2014-01-01

    Ex vivo lung perfusion (EVLP) is a powerful experimental model for isolated lung research. EVLP allows for the lungs to be manipulated and characterized in an external environment so that the effect of specific ventilation/perfusion variables can be studied independent of other confounding physiologic contributions. At the same time, EVLP allows for normal organ level function and real-time monitoring of pulmonary physiology and mechanics. As a result, this technique provides unique advantages over in vivo and in vitro models. Small and large animal models of EVLP have been developed and each of these models has their strengths and weaknesses. In this manuscript, we provide insight into the relative strengths of each model and describe how the development of advanced EVLP protocols is leading to a novel experimental platform that can be used to answer critical questions in pulmonary physiology and transplant medicine. PMID:24977117

  14. Animal models of ex vivo lung perfusion as a platform for transplantation research.

    PubMed

    Nelson, Kevin; Bobba, Christopher; Ghadiali, Samir; Hayes, Don; Black, Sylvester M; Whitson, Bryan A

    2014-05-20

    Ex vivo lung perfusion (EVLP) is a powerful experimental model for isolated lung research. EVLP allows for the lungs to be manipulated and characterized in an external environment so that the effect of specific ventilation/perfusion variables can be studied independent of other confounding physiologic contributions. At the same time, EVLP allows for normal organ level function and real-time monitoring of pulmonary physiology and mechanics. As a result, this technique provides unique advantages over in vivo and in vitro models. Small and large animal models of EVLP have been developed and each of these models has their strengths and weaknesses. In this manuscript, we provide insight into the relative strengths of each model and describe how the development of advanced EVLP protocols is leading to a novel experimental platform that can be used to answer critical questions in pulmonary physiology and transplant medicine. PMID:24977117

  15. Myocardial performance and perfusion during exercise in patients with coronary artery disease caused by Kawasaki disease

    SciTech Connect

    Paridon, S.M.; Ross, R.D.; Kuhns, L.R.; Pinsky, W.W. (Wayne State Univ. School of Medicine, Detroit (USA))

    1990-01-01

    For a study of the natural history of coronary artery lesions after Kawasaki disease and their effect on myocardial blood flow reserve with exercise, five such patients underwent exercise testing on a bicycle. Oxygen consumption, carbon dioxide production, minute ventilation, and electrocardiograms were monitored continuously. Thallium-201 scintigraphy was performed for all patients. One patient stopped exercise before exhaustion of cardiovascular reserve but had no evidence of myocardial perfusion abnormalities. Four patients terminated exercise because of exhaustion of cardiovascular reserve; one had normal cardiovascular reserve and thallium scintiscans, but the remaining patients had diminished cardiovascular reserve. Thallium scintigrams showed myocardial ischemia in two and infarction in one. No patient had exercise-induced electrocardiographic changes. These results indicate that patients with residual coronary artery lesions after Kawasaki disease frequently have reduced cardiovascular reserve during exercise. The addition of thallium scintigraphy and metabolic measurements to exercise testing improved the detection of exercise-induced abnormalities of myocardial perfusion.

  16. 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.

  17. Cigarette smoke ventilation decreases prostaglandin inactivation in rat and hamster lungs

    SciTech Connect

    Maennistoe, J.; Uotila, P.

    1982-06-01

    The effects of cigarette smoke on the metabolism of exogenous PGE2 and PGF2 alpha were investigated in isolated rat and hamster lungs. When isolated lungs from animals were ventilated with cigarette smoke during pulmonary infusion of 100 nmol of PGE2 or PGF2 alpha, the amounts of the 15-keto-metabolites in the perfusion effluent were decreased. Pre-exposure of animals to cigarette smoke daily for 3 weeks did not change the metabolism of PGE2 when the lungs were ventilated with air. Cigarette smoke ventilation of lungs from pre-exposed animals caused, however, a similar decrease in the metabolism of PGE2 as in animals not previously exposed to smoke. After pulmonary injection of 10 nmol of /sup 14/C-PGE2 the radioactivity appeared more rapidly in the effluent during cigarette smoke ventilation suggesting inhibition of the PGE2 uptake mechanism. In rat lungs pulmonary vascular pressor responses to PGE2 and PGF2 alpha were inhibited by smoke ventilation.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. Advanced Controls and Sustainable Systems for Residential Ventilation

    E-print Network

    1 Advanced Controls and Sustainable Systems for Residential Ventilation William J.N. Turner & Iain..................................................................................................................... 8 Residential Ventilation Standards..........................................................................................9 Passive and Hybrid Ventilation

  4. Mechanical Ventilation in Children - Problems and Issues.

    PubMed

    Zieli?ska, Marzena; Zieli?ski, Stanis?aw; Sniatkowska-Bartkowska, Alicja

    2014-01-01

    Respiratory failure is the leading reason for the admission of children to intensive care units, and the ventilator is the main therapeutic tool used during the treatment of these patients. A competently used ventilator and adequate knowledge of the anatomy, histology and physiology of the respiratory system in particular age groups of children (especially among neonates and infants) are crucial for successful treatment. Both non-invasive and invasive ventilation modes can be used for respiratory treatment in children. Invasive ventilation modes can be divided into two groups: conventional ones such as pressure-controlled or volume-controlled ventilation, or non-conventional modes such as oscillatory ventilation. Mechanical ventilation can involve a high risk of serious complications, such as pressure injury (barotrauma), volume injury (volutrauma) and biotrauma. Adhering to the principles of lung-protective ventilation can reduce the risk of side effects of mechanical ventilation. PMID:25491702

  5. [Ventilation in special situations. Mechanical ventilation in status asthmaticus].

    PubMed

    Molini Menchón, N; Ibiza Palacios, E; Modesto i Alapont, V

    2003-10-01

    The indications for mechanical ventilation in status asthmaticus are cardiopulmonary arrest, significant alteration of consciousness, respiratory exhaustion, and progressive respiratory insufficiency despite aggressive bronchodilator treatment. In mechanical ventilation for status asthmaticus, a specific strategy directed at reducing dynamic hyperinflation must be used, with low tidal volumes and long expiratory times, achieved by diminishing respiratory frequency. This ventilatory pattern produces permissive hypercapnia, which is generally well tolerated with suitable sedation. The best methods for detecting and/or controlling dynamic hyperinflation in ventilated patients with status asthmaticus are the flow/time and flow/volume respiratory curves, pulmonary volume at the end of inspiration, and the pressure plateau. In addition to mechanical ventilation the child must receive sedation with or without a muscle relaxant to prevent barotrauma and accidental extubation. Bronchodilator treatment with beta-adrenergic agonists, methyl-prednisolone, and intravenous aminophylline are also required. A combination of inhaled salbutamol and nebulized ipratropium in the inspiratory branch of the ventilator should be used in patients in whom this treatment is effective. Currently there is insufficient evidence on the efficiency of other treatments in status asthmaticus and these should be used as rescue treatments. PMID:14519306

  6. Parental genome dosage imbalance deregulates imprinting in Arabidopsis.

    PubMed

    Jullien, Pauline E; Berger, Frédéric

    2010-03-01

    In mammals and in plants, parental genome dosage imbalance deregulates embryo growth and might be involved in reproductive isolation between emerging new species. Increased dosage of maternal genomes represses growth while an increased dosage of paternal genomes has the opposite effect. These observations led to the discovery of imprinted genes, which are expressed by a single parental allele. It was further proposed in the frame of the parental conflict theory that parental genome imbalances are directly mirrored by antagonistic regulations of imprinted genes encoding maternal growth inhibitors and paternal growth enhancers. However these hypotheses were never tested directly. Here, we investigated the effect of parental genome imbalance on the expression of Arabidopsis imprinted genes FERTILIZATION INDEPENDENT SEED2 (FIS2) and FLOWERING WAGENINGEN (FWA) controlled by DNA methylation, and MEDEA (MEA) and PHERES1 (PHE1) controlled by histone methylation. Genome dosage imbalance deregulated the expression of FIS2 and PHE1 in an antagonistic manner. In addition increased dosage of inactive alleles caused a loss of imprinting of FIS2 and MEA. Although FIS2 controls histone methylation, which represses MEA and PHE1 expression, the changes of PHE1 and MEA expression could not be fully accounted for by the corresponding fluctuations of FIS2 expression. Our results show that parental genome dosage imbalance deregulates imprinting using mechanisms, which are independent from known regulators of imprinting. The complexity of the network of regulations between expressed and silenced alleles of imprinted genes activated in response to parental dosage imbalance does not support simple models derived from the parental conflict hypothesis. PMID:20333248

  7. Interplay between nuclear factor erythroid 2-related factor 2 and amphiregulin during mechanical ventilation.

    PubMed

    Reiss, Lucy Kathleen; Fragoulis, Athanassios; Siegl, Stephanie; Platen, Christopher; Kan, Yuet Wai; Nautiyal, Jaya; Parker, Malcom; Pufe, Thomas; Uhlig, Ulrike; Martin, Christian; Uhlig, Stefan; Wruck, Christoph Jan

    2014-11-01

    Mechanical ventilation (MV) elicits complex and clinically relevant cellular responses in the lungs. The current study was designed to define the role of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), a major regulator of the cellular antioxidant defense system, in the pulmonary response to MV. Nrf2 activity was quantified in ventilated isolated perfused mouse lungs (IPL). Regulation of amphiregulin (AREG) was investigated in BEAS-2B cells with inactivated Nrf2 or Keap1, the inhibitor of Nrf2, using a luciferase vector with AREG promoter. AREG-dependent Nrf2 activity was examined in BEAS-2B cells, murine precision-cut lung slices (PCLS), and IPL. Finally, Nrf2 knockout and wild-type mice were ventilated to investigate the interplay between Nrf2 and AREG during MV in vivo. Lung functions and inflammatory parameters were measured. Nrf2 was activated in a ventilation-dependent manner. The knockdown of Nrf2 and Keap1 via short hairpin RNA in BEAS-2B cells and an EMSA with lung tissue revealed that AREG is regulated by Nrf2. Conversely, AREG application induced a significant Nrf2 activation in BEAS-2B cells, PCLS, and IPL. The signal transduction of ventilation-induced Nrf2 activation was shown to be p38 MAP kinase-dependent. In vivo ventilation experiments indicated that AREG is regulated by Nrf2 during MV. We conclude that Areg expression is regulated by Nrf2. During high-pressure ventilation, Nrf2 becomes activated and induces AREG, leading to a positive feedback loop between Nrf2 and AREG, which involves the p38 MAPK and results in the expression of cytoprotective genes. PMID:24921206

  8. Shoulder muscle imbalance and subacromial impingement syndrome in overhead athletes.

    PubMed

    Page, Phil

    2011-03-01

    Subacromial impingement is a frequent and painful condition among athletes, particularly those involved in overhead sports such as baseball and swimming. There are generally two types of subacromial impingement: structural and functional. While structural impingement is caused by a physical loss of area in the subacromial space due to bony growth or inflammation, functional impingement is a relative loss of subacromial space secondary to altered scapulohumeral mechanics resulting from glenohumeral instability and muscle imbalance. The purpose of this review is to describe the role of muscle imbalance in subacromial impingement in order to guide sports physical therapy evaluation and interventions. PMID:21655457

  9. 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).

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. Energy Impact of Residential Ventilation Standards in California

    E-print Network

    ...................................................................................................................................... 6 Non-compliant systems .............................................................................................................................. 7 Source Control Ventilation...................................................................................................

  16. 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...

  17. 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.

  18. 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.

  19. Dilation based modeling of perfusion datasets.

    PubMed

    Rosiene, J; Imielinska, C; Liu, X; Keating, S

    2005-01-01

    A new approach to the modeling of the marker in Perfusion CT and Perfusion MR datasets is outlined and initial results given. The technique is based on estimation of the dilation and delay of an estimated bolus shape and a template fit to an new solution of the heat equation. Initial results are provided. PMID:16779385

  20. Oral alprazolam acutely increases nucleus accumbens perfusion

    PubMed Central

    Wolf, Daniel H.; Pinkham, Amy E.; Satterthwaite, Theodore D.; Ruparel, Kosha; Elliott, Mark A.; Valdez, Jeffrey; Smith, Mark A.; Detre, John A.; Gur, Ruben C.; Gur, Raquel E.

    2014-01-01

    Benzodiazepines treat anxiety, but can also produce euphoric effects, contributing to abuse. Using perfusion magnetic resonance imaging, we provide the first direct evidence in humans that alprazolam (Xanax) acutely increases perfusion in the nucleus accumbens, a key reward-processing region linked to addiction. PMID:23070072

  1. POLICY IMPLICATIONS OF THE GENDER IMBALANCE AMONG AMERICA'S JEWS

    Microsoft Academic Search

    Sylvia Barack Fishman; Daniel Parmer

    2008-01-01

    Within the liberal wings of American Judaism, women are increasingly prominent both as leaders and participants, and men are increasingly marginal. This gender imbalance differs from most Jewish communities historically and from many other Jewish communities around the world today, in which men characteristically played the most prominent roles in Jewish affairs as well as public religious settings and rituals.

  2. Forecasting system imbalance volumes in competitive electricity markets

    Microsoft Academic Search

    M. P. Garcia; D. S. Kirschen

    2004-01-01

    Forecasting in power systems has been made considerably more complex by the introduction of competitive electricity markets. Furthermore, new variables need to be predicted by various market participants. This paper shows how a new methodology that combines classical and data mining techniques can be used to forecast the system imbalance volume, a key variable for the system operator in the

  3. Forecasting system imbalance volumes in competitive electricity markets

    Microsoft Academic Search

    Maria P. Garcia; Daniel S. Kirschen

    2006-01-01

    Forecasting in power systems has been made considerably more complex by the introduction of competitive electricity markets. Furthermore, new variables need to be predicted by various market participants. This paper shows how a new methodology that combines classical and data mining techniques can be used to forecast the system imbalance volume, a key variable for the system operator in the

  4. Fear and Market Failure: Global Imbalances and “Self-Insurance”

    Microsoft Academic Search

    Marcus Miller; Lei Zhang

    2007-01-01

    This paper proposes an integrated framework to analyze jointly two key issues: the emergence of global imbalances and the precautionary motive for accumulating reserves. Standard models of general equilibrium would predict modest current account surpluses in the emerging markets if they face higher risk than the US itself. But, with pronounced Loss Aversion in emerging markets, their precautionary savings can

  5. Fracture of sea ice sheets due to isostatic imbalance

    Microsoft Academic Search

    Richard T. Schwaegler

    1974-01-01

    The non uniform thickness of sea ice sheets creates regions of isostatic shear imbalance. For assumed ice thickness variation, the resulting bening stresses are determined sufficient to cause cracking. The ice sheet is modeled as a floating elastic plate with constant flexural rigidity. Variable thickness is obtained by representing the bottom surface as a sine wave. Upper and lower bound

  6. Improving Academic Performance Prediction by Dealing with Class Imbalance

    Microsoft Academic Search

    Nguyen Thai-Nghe; Andre Busche; Lars Schmidt-Thieme

    2009-01-01

    This paper introduces and compares some techniques used to predict the student performance at the university. Recently, researchers have focused on applying machine learning in higher education to support both the students and the instructors getting better in their performances. Some previous papers have introduced this problem but the prediction results were unsatisfactory because of the class imbalance problem, which

  7. 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...

  8. THEME ARTICLE On the imbalance of the security

    E-print Network

    the results. Practical implications ­ As the arms race in computer security progresses, social factors may in the computer security community and for considering computer security problem space through the lens of socialTHEME ARTICLE On the imbalance of the security problem space and its expected consequences

  9. Global Imbalances and the U.S. Trade Deficit

    E-print Network

    Lansky, Joshua

    . Nonetheless, this chapter argues that the U.S. trade deficit and foreign trade surpluses were at leastGlobal Imbalances and the U.S. Trade Deficit By Robert A. Blecker* Revised May 2011 * Professor.S. and foreign economies slowly recover from the financial crisis and Great Recession of 2008-9, attention

  10. Bayes Vector Quantizer for Class-Imbalance Problem

    Microsoft Academic Search

    Claudia Diamantini; Domenico Potena

    2009-01-01

    The class-imbalance problem is the problem of learning a classification rule from data that are skewed in favor of one class. On these datasets traditional learning techniques tend to overlook the less numerous class, at the advantage of the majority class. However, the minority class is often the most interesting one for the task at hand. For this reason, the

  11. Global Imbalances: Should We Use Fundamental Equilibrium Exchange Rates?

    E-print Network

    Paris-Sud XI, Université de

    % of world GDP in absolute value. As pointed out by Blanchard and Milesi-Ferretti (2012), the persistence of large current account imbalances and large net foreign assets positions is a threat for the world growth in advanced countries, the perpetuation of export-led growth strategies in some emerging countries

  12. Ventilation-Synchronous Magnetic Resonance Microscopy of Pulmonary Structure and Ventilation in

    E-print Network

    Ventilation-Synchronous Magnetic Resonance Microscopy of Pulmonary Structure and Ventilation helium (3 He) gas to acquire images that dem- onstrate pulmonary vasculature and ventilated airways of these structures relative to the less vascular surrounding tissues. A constant- flow ventilator was developed

  13. 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

  14. STATE OF CALIFORNIA MECHANICAL VENTILATION AND REHEAT

    E-print Network

    STATE OF CALIFORNIA MECHANICAL VENTILATION AND REHEAT CEC-MECH-3C (Revised 08/09) CALIFORNIA ENERGY COMMISSION MECHANICAL VENTILATION AND REHEAT MECH-3C PROJECT NAME DATE MECHANICAL VENTILATION §121(b)2 REHEAT'D V.A. Max of D or G Design Ventilation Air cfm 50% of Design Zone Supply cfm B x 0.4 cfm/ft² Max

  15. Equipment needs for noninvasive mechanical ventilation

    Microsoft Academic Search

    B. Schonhofer; S. Sortor-Leger

    2002-01-01

    ABSTRACT: Noninvasive mechanical,ventilation (NIV) has a long tradition for the treatment of chronic respiratory failure and more recently has also been applied in acute respiratory failure. Based on this experience both critical care ventilators and portable ventilators are used to perform,NIV. The individual choice of ventilator type should depend on the patient9s condition and also on the expertise of attending

  16. Cardiac MR perfusion imaging: where we are.

    PubMed

    Marano, Riccardo; Natale, Luigi; Chiribiri, Amedeo; Pirro, Federica; Silvestri, Valentina; Coppola, Giuseppe; Bonomo, Lorenzo

    2015-02-01

    To date, several clinical and multicentre studies have demonstrated the accuracy of perfusion cardiac magnetic resonance to detect ischaemia in comparison with quantitative coronary angiography, other noninvasive diagnostic techniques (single photon emission computed tomography; positron-emission tomography), and invasive haemodynamic measurements (fractional flow reserve). Moreover, the favourable safety profile and increasing availability contribute to make perfusion cardiac magnetic resonance one of the modalities of choice for the detection of myocardial ischaemia. Recently, the first evidence of the prognostic value of perfusion cardiac magnetic resonance results has also become available. This review summarises the technical and interpretation key points of perfusion cardiac magnetic resonance scan, the clinical indications, the most recent available literature about its diagnostic performance and prognostic value, and how perfusion cardiac magnetic resonance compares with other noninvasive techniques. PMID:25030969

  17. Mouse isolated perfused heart: characteristics and cautions.

    PubMed

    Sutherland, Fiona J; Shattock, Michael J; Baker, Kathryn E; Hearse, David J

    2003-11-01

    1. Owing to the considerable potential for manipulating the murine genome and, as a consequence, the increasing availability of genetically modified models of cardiovascular diseases, the mouse is fast becoming a cornerstone of animal research. However, progress in the use of various murine preparations is hampered by the lack of facilities and skills for the adequate physiological assessment of genetically modified mice. 2. We have attempted to address this problem by refining and characterizing a mouse isolated heart preparation that was originally developed for use with larger hearts. 3. We used the isolated buffer-perfused Langendorff preparation (perfused at constant flow or constant pressure) to characterize: (i) the frequency-response characteristics; (ii) heart isolation conditions; (iii) perfusion chamber conditions; (iv) temperature-function relationships; (v) stability over extended periods of perfusion; (vi) perfusate calcium-function relationships; (vii) pressure-volume relationships; (viii) pressure-rate relationships; and (ix) flow-function relationships. PMID:14678252

  18. 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...

  19. 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,...

  20. Procedures and Standards for Residential Ventilation System

    E-print Network

    1 Procedures and Standards for Residential Ventilation System Commissioning: An Annotated and by the California Energy Commission under Pier Contract 500-08-061. Key terms: residential, ventilation.C. and C.P. Wray. 2013. Procedures and Standards for Residential Ventilation System Commissioning

  1. 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...

  2. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Ventilation. 98.25-75 Section 98.25-75...Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing...connections shall be provided with mechanical ventilation of sufficient capacity to...

  3. 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...

  4. 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...

  5. 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...

  6. Reduceret energiforbrug til ventilation af bygninger

    E-print Network

    Reduceret energiforbrug til ventilation af bygninger hvori der systematisk er valgt lav. 23. November 2007 #12;#12;Reduced energy use for ventilation of buildings through selection of low ventilation rate on perceived quality of air polluted by different materials, small ­ scale and full ­ scale

  7. 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...

  8. 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...

  9. 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...

  10. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Ventilation. 98.25-75 Section 98.25-75...Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing...connections shall be provided with mechanical ventilation of sufficient capacity to...

  11. 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...

  12. 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...

  13. 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...

  14. The fluid mechanics of natural ventilation

    Microsoft Academic Search

    Paul Linden

    1999-01-01

    Natural ventilation of buildings is the flow generated by temperature differences and by the wind. Modern buildings have extreme designs with large, tall open plan spaces and large cooling requirements. Natural ventilation offers a means of cooling these buildings and providing good indoor air quality. The essential feature of ventilation is an exchange between an interior space and the external

  15. 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...

  16. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Ventilation. 98.25-75 Section 98.25-75...Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing...connections shall be provided with mechanical ventilation of sufficient capacity to...

  17. 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...

  18. 46 CFR 98.25-75 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Ventilation. 98.25-75 Section 98.25-75...Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing...connections shall be provided with mechanical ventilation of sufficient capacity to...

  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. 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...

  1. 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,...

  2. Humidity Implications for Meeting Residential Ventilation Requirements

    E-print Network

    1 LBNL-62182 Humidity Implications for Meeting Residential Ventilation Requirements Iain S. Walker for Meeting Residential Ventilation Requirements ABSTRACT In 2003 ASHRAE approved the nation's first residential ventilation standard, ASHRAE Standard 62.2. Because meeting this standard can significantly change

  3. 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

  4. 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...

  5. 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,...

  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 98.25-75 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Ventilation. 98.25-75 Section 98.25-75...Anhydrous Ammonia in Bulk § 98.25-75 Ventilation. (a) All enclosed spaces containing...connections shall be provided with mechanical ventilation of sufficient capacity to...

  8. Formaldehyde Transfer in Residential Energy Recovery Ventilators

    E-print Network

    Formaldehyde Transfer in Residential Energy Recovery Ventilators Erin L. Hult, Henry Willem and Max and Sherman MH, 2014, Formaldehyde transfer in residential energy recovery ventilators, Building design used in many energy recovery ventilators (ERVs) is designed to transfer heat and moisture between

  9. 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.

  10. Ventilator for internal combustion engine

    Microsoft Academic Search

    Aoki

    1986-01-01

    A ventilator is described for an internal combustion engine, consisting of: a housing; a diaphragm that divides the inside of the housing into a pressure chamber communicating with a crankcase and an atmospheric chamber communicating with the atmosphere; an outlet tube extending vertically in the pressure chamber and communicating with an intake manifold; a valve fixed to the diaphragm and

  11. 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.

  12. TISSUE ENGINEERING PERFUSABLE CANCER MODELS

    PubMed Central

    Fong, E.L.; Santoro, M.; Farach-Carson, M.C.; Kasper, F.K.; Mikos, A.G.

    2014-01-01

    The effect of fluid flow on cancer progression is currently not well understood, highlighting the need for perfused tumor models to close this gap in knowledge. Enabling biological processes at the cellular level to be modeled with high spatiotemporal control, microfluidic tumor models have demonstrated applicability as platforms to study cell-cell interactions, effect of interstitial flow on tumor migration and the role of vascular barrier function. To account for the multi-scale nature of cancer growth and invasion, macroscale models are also necessary. The consideration of fluid dynamics within tumor models at both the micro- and macroscopic levels may greatly improve our ability to more fully mimic the tumor microenvironment. PMID:24634812

  13. Pulmonary Perfused Blood Volume with Dual-Energy CT as Surrogate for Pulmonary Perfusion Assessed with Dynamic Multidetector CT

    PubMed Central

    Fuld, Matthew K.; Halaweish, Ahmed F.; Haynes, Susan E.; Divekar, Abhay A.; Guo, Junfeng

    2013-01-01

    Purpose: To compare measurements of regional pulmonary perfused blood volume (PBV) and pulmonary blood flow (PBF) obtained with computed tomography (CT) in two pig models. Materials and Methods: The institutional animal care and use committee approved all animal studies. CT-derived PBF and PBV were determined in four anesthetized, mechanically ventilated, supine swine by using two methods for creating pulmonary parenchymal perfusion heterogeneity. Two animals were examined after sequentially moving a pulmonary arterial balloon catheter from a distal to a central location, and two others were examined over a range of static airway pressures, which varied the extents of regional PBF. Lung sections were divided into blocks and Pearson correlation coefficients calculated to compare matching regions between the two methods. Results: CT-derived PBF, CT-derived PBV, and their associated coefficients of variation (CV) were closely correlated on a region-by-region basis in both the balloon occlusion (Pearson R = 0.91 and 0.73 for animals 1 and 2, respectively; Pearson R = 0.98 and 0.87 for comparison of normalized mean and CV for animals 1 and 2, respectively) and lung inflation studies (Pearson R = 0.94 and 0.74 for animals 3 and 4, respectively; Pearson R = 0.94 and 0.69 for normalized mean and CV for animals 3 and 4, respectively). When accounting for region-based effects, correlations remained highly significant at the P < .001 level. Conclusion: CT-derived PBV heterogeneity is a suitable surrogate for CT-derived PBF heterogeneity. ©RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112789/-/DC1 PMID:23192773

  14. Night ventilation control strategies in office buildings

    SciTech Connect

    Wang, Zhaojun; Yi, Lingli; Gao, Fusheng [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    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)

  15. Temperature controlled machine perfusion system for liver.

    PubMed

    Obara, H; Matsuno, N; Shigeta, T; Hirano, T; Enosawa, S; Mizunuma, H

    2013-06-01

    Organ preservation using machine perfusion is an effective method compared with conventional preservation techniques using static cold storage. A newly developed MP preservation system to control perfusate temperatures from hypothermic to subnormothermic conditions is introduced. This system is useful not only for liver preservation, but also for evaluation of graft viability for recovery. This novel method has been proposed for preservation of porcine liver grafts. An innovative preservation system is especially important to obtain viable organs from extended criteria or donation after cardiac death donors. In this study, we introduce a new machine perfusion preservation system (NES-01) to evaluate graft viability for recovery of liver functions, using porcine grafts. PMID:23769025

  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. Comparative evaluation of the effects of indomethacin and ibuprofen on cerebral perfusion and oxygenation in preterm infants with patent ductus arteriosus

    Microsoft Academic Search

    Fabio Mosca; Milena Bray; Maria Lattanzio; Monica Fumagalli; Camillo Tosetto

    1997-01-01

    Objective: To compare the effects on cerebral perfusion and oxygenation of intravenous ibuprofen and indomethacin as treatment for patent ductus arteriosus in preterm infants.Study design: Sixteen infants receiving mechanical ventilation (< 31 weeks gestation) with patent ductus arteriosus received either 0.2 mg\\/kg indomethacin ( n = 8) or 10 mg\\/kg ibuprofen ( n = 8) infused over 1 minute. Near-infrared

  18. 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

  19. 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.

  20. Thrust imbalance of the Space Shuttle solid rocket motors

    NASA Technical Reports Server (NTRS)

    Foster, W. A., Jr.; Sforzini, R. H.; Shackelford, B. W., Jr.

    1981-01-01

    The Monte Carlo statistical analysis of thrust imbalance is applied to both the Titan IIIC and the Space Shuttle solid rocket motors (SRMs) firing in parallel, and results are compared with those obtained from the Space Shuttle program. The test results are examined in three phases: (1) pairs of SRMs selected from static tests of the four developmental motors (DMs 1 through 4); (2) pairs of SRMs selected from static tests of the three quality assurance motors (QMs 1 through 3); (3) SRMs on the first flight test vehicle (STS-1A and STS-1B). The simplified internal ballistic model utilized for computing thrust from head-end pressure measurements on flight tests is shown to agree closely with measured thrust data. Inaccuracies in thrust imbalance evaluation are explained by possible flight test instrumentation errors.

  1. Preliminary Report of a Mathematical Model of Ventilation and Intrathoracic Pressure Applied to Prehospital Patients with Severe Traumatic Brain Injury.

    PubMed

    Davis, Daniel P; Aguilar, Steve A; Smith, Kimberly; Husa, Ruchika D; Minokadeh, Anushirvan; Vilke, Gary; Sell, Rebecca; Fisher, Roger; Brainard, Criss; Dunford, James V

    2014-10-01

    Abstract Background: Inadvertent hyperventilation is associated with poor outcomes from traumatic brain injury (TBI). Hypocapnic cerebral vasoconstriction is well described and causes an immediate and profound decrease in cerebral perfusion. The hemodynamic effects of positive-pressure ventilation (PPV) remain incompletely understood but may be equally important, particularly in the hypovolemic patient with TBI. Objective: Preliminary report on the application of a previously described mathematical model of perfusion and ventilation to prehospital data to predict intrathoracic pressure. Methods: Ventilation data from 108 TBI patients (76 ground transported, 32 helicopter transported) were used for this analysis. Ventilation rate (VR) and end-tidal carbon dioxide (PetCO2) values were used to estimate tidal volume (VT). The values for VR and estimated VT were then applied to a previously described mathematical model of perfusion and ventilation. This model allows input of various lung parameters to define a pressure-volume relationship, then derives mean intrathoracic pressure (MITP) for various VT and VR values. For this analysis, normal lung parameters were utilized. Separate analyses were performed assuming either fixed or variable PaCO2-PetCO2 differences. Ground and air medical patients were compared with regard to VR, PetCO2, estimated VT, and predicted MITP. Results: A total of 10,647 measurements were included from the 108 TBI patients, representing about 13 minutes of ventilation per patient. Mean VR values were higher for ground patients versus air patients (21.6 vs. 19.7 breaths/min; p < 0.01). Estimated VT values were similar for ground and air patients (399 mL vs. 392 mL; p = NS) in the fixed model but not the variable (636 vs. 688 mL, respectively; p < 0.01). Mean PetCO2 values were lower for ground versus air patients (30.6 vs. 33.8 mmHg; p < 0.01). Predicted MITP values were higher for ground versus air patients, assuming either fixed (9.0 vs. 8.1 mmHg; p < 0.01) or variable (10.9 vs. 9.7 mmHg; p < 0.01) PaCO2-PetCO2 differences. Conclusions: Predicted MITP values increased with ventilation rates. Future studies to externally validate this model are warranted. PMID:25291381

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

    SciTech Connect

    Drummond, W.H.; Lyles, D. (Univ. of Florida, Gainesville (United States))

    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.

  3. Effect of carbon monoxide on xenobiotic metabolism in the isolated perfused rabbit lung

    SciTech Connect

    Trela, B.A.

    1988-01-01

    It was the aim of this study to determine the level and duration of CO exposure necessary to alter mixed function oxidase-mediated activity in the intact lung and to determine the magnitude of this effect. The effect of CO on the mixed function oxidase-mediated activities of aminopyrine, aniline, 4-ipomeanol and p-nitroanisole in isolated perfused rabbit lungs (IPRL) was investigated. Several concentrations of CO were evaluated for their effect on cytochrome P-450-mediated activity in the lung. Both artificial medium and whole blood were utilized as recirculating perfusates. Monomethyl-4-aminoantipyrine was the major metabolite of aminopyrine produced by in vitro hepatic and pulmonary preparations and by the intact lung. Ventilation of isolated rabbit lungs with 7.5% CO for 2.5 hours caused a 40% decrease in the rates of metabolism of both aminopyrine and p-nitroanisole. This level of CO exposure did not alter the cytochrome P-450-mediated metabolism of aniline nor 4-ipomeanol in the intact lung. Aminopyrine metabolism in isolated rabbit lungs perfused with whole blood was also decreased following the administration of 7.5% CO suggesting that the hemoglobin in whole blood affords no protection against CO-induced inhibition of mixed function oxidase activity in the intact lung. The isozyme of cytochrome P-450 which preferentially metabolizes aminopyrine and p-nitroanisole may be more sensitive to CO-induced inhibition than the form(s) which metabolize aniline and 4-ipomeanol.

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

    SciTech Connect

    Rimar, S.; Gillis, C.N. [Yale Univ. School of Medicine, New Haven, CT (United States)

    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.

  5. 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

  6. TRANSCARDIAL PERFUSION FIXATION (SOP-29) INTRODUCTION

    E-print Network

    Kleinfeld, David

    tissue should be performed in a fume hood. TRANSCARDIAL PERFUSION 1. The animal is injected with 2x. Make a third #12;2 incision across the ventral aspect of the trunk at the level of the xiphisternum. 4

  7. 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.

  8. Normothermic blood perfusion of isolated rabbit kidneys

    Microsoft Academic Search

    Françoise G. Arnaud; Bijan S. Khirabadi; Gregory M. Fahy

    2002-01-01

    Cryopreservation of solid organs might be possible using a mixture of cell-permeable agents, cryoprotectants (CPA), which are designed to completely preclude ice crystal formation during cooling to cryogenic temperatures. The effects of a specific prototype solution (VS4) were evaluated by normothermic blood perfusion in vitro. Rabbit kidneys were divided into three groups: untreated controls (n=7), Euro-Collins (EC)-perfused controls (n=6) and

  9. 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

  10. 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.

  11. 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.

  12. CONFIDENTIAL: DO NOT QUOTE 1 Equivalence in Ventilation and

    E-print Network

    CONFIDENTIAL: DO NOT QUOTE 1 Equivalence in Ventilation and Indoor Air Quality M. H. Sherman, I ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation

  13. Architectural design of an advanced naturally ventilated building form

    Microsoft Academic Search

    Kevin J. Lomas

    2007-01-01

    Advanced stack-ventilated buildings have the potential to consume much less energy for space conditioning than typical mechanically ventilated or air-conditioned buildings. This paper describes how environmental design considerations in general, and ventilation considerations in particular, shape the architecture of advanced naturally ventilated (ANV) buildings. The attributes of simple and advanced naturally ventilated buildings are described and a taxonomy of ANV

  14. Ventilation Requirements in Hot Humid Climates

    E-print Network

    Walker, I. S.; Sherman, M. H.

    2006-01-01

    VENTILATION REQUIREMENTS IN HOT, HUMID CLIMATES I.S. Walker M. H. Sherman Staff Scientist Senior Scientist Lawrence Berkeley National Laboratory Berkeley CA ABSTRACT In 2003 ASHRAE approved the nation’s first residential... ventilation standard, ASHRAE Standard 62.2. Meeting this standard in new construction requires the use of mechanical ventilation, which in turn can often significantly increase the latent load faced in new homes. As the thermal performance of houses...

  15. High-frequency ventilation and conventional mechanical ventilation in newborn babies with respiratory distress syndrome: A prospective, randomized trial

    Microsoft Academic Search

    A. Pardou; D. Vermeylen; M. F. Muller; D. Detemmerman

    1993-01-01

    Objective. Morbidity and mortality remain high amongst babies ventilated for a respiratory distress syndrome (RDS). Whether newly developed ventilators allowing high frequency ventilation such as high frequen- cy flow interrupted ventilation (HFFIV) could decrease the morbidity and the mortality was investigated in a ran- domized study. Design: Preterm babies weighing < 1800 g suffering from RDS and ventilated by conventional

  16. What is the Imbalance of Water in Nature?

    NASA Astrophysics Data System (ADS)

    Kontar, V. A.

    2011-12-01

    Look at any lake. Water comes into the lake from the atmosphere, from surface and groundwater sources. Water leaves the lake to the atmosphere, surface and underground drains, as well as for consumption by human society, wild plants and animals if they are within the boundaries of the lake's system. If quantity of water coming into the lake is equally of the quantity of water which flow from the lake, so the lake level has not changed and we have a state of equilibration or balance. The bookkeeper's book also has name "balance". But this is just a play on words. If the water is coming into the lake more than the water is coming away from lake, therefore the lake level will increase and we have a state of the imbalance of the increase type. If the water is coming into the lake less than the water is coming away from lake, therefore the lake level will decrease and we have a state of the imbalance of the decrease type. Everyone knows that the lake level rises or falls, for example during the year. Sometimes it is happened some balance. But the state of balance is rare and in of the short duration. The lake is of most the time in the conditions of the imbalance increases or the imbalance decreases type. The balance as a state of equilibrium, in the language of mathematics, is the point of the extremum between the periods of rise and fall. The balance is a special condition, which is existing very rare and a very short period of time. The people sometimes to do the great efforts for maintain the constant level of the lakes. But these facts don't change the situation. On the contrary, the human's struggle for maintain the lake in constant level just shows how difficult and expensive to go against the natural laws of Nature. When water was plentiful, these facts could be ignored. But now when the global water shortage is quickly growing, many previously ignored details are becoming crucial. There are very important to do the correct definitions of the borders and parameters of the system. The precise of the measurement of the parameters system have the decisive role. The systemic approach to addressing the imbalance, we will describe in another separate paper. Now in our case, the lake and its effective environment is one system. It is possible so roughly determine the system of lakes that will be always to do the report exact which wants the boss. It is happened quite often. For example, it was the time when the human's leaders have used the hypothesis that the Earth is flat and the Sky is hard. This dominant interpretation of the Nature was used by force a lot of centuries. Who were disagreed with these statements those were burned at the stake, etc. This situation was change only when the domestic recourses were exhausted. The new recourses were possible to get as expansion to other countries, continents, space etc. The flat Earth and the hard Sky not help more. Now the balance idea is in some similar situation. The balance is a convenient, relaxing hypothesis or model. This model gave a lot of opportunities for the development of science and practice in the past. But the humanity is in other conditions now. Rest we have only on the dream. The era of the balance is going to end. The era of the imbalance is coming now for future. The humanity must to learn to live in an era of great change or disappear.

  17. Regional Lung Derecruitment and Inflammation during 16 Hours of Mechanical Ventilation in Supine Healthy Sheep

    PubMed Central

    Tucci, Mauro R.; Costa, Eduardo L.V.; Wellman, Tyler J.; Musch, Guido; Winkler, Tilo; Harris, R. Scott; Venegas, Jose G.; Amato, Marcelo B. P.; Vidal Melo, Marcos F.

    2014-01-01

    Background Lung derecruitment is common during general anesthesia. Mechanical ventilation with physiological tidal volumes could magnify derecruitment, and produce lung dysfunction and inflammation. We used Positron Emission Tomography to study the process of derecruitment in normal lungs ventilated for 16 h, and the corresponding changes in regional lung perfusion and inflammation. Methods Six anesthetized supine sheep were ventilated with VT = 8mL/kg and positive end-expiratory pressure = 0. Transmission scans were obtained at 2-h intervals to assess regional aeration. Emission scans were acquired at baseline and after 16 h for the tracers: (a) 18F-fluorodeoxyglucose to evaluate lung inflammation, and (b) 13NN to calculate regional perfusion and shunt fraction. Results Gas fraction decreased from baseline to 16 h in dorsal (0.31 ± 0.13 to 0.14 ± 0.12, P < 0.01) but not ventral regions (0.61 ± 0.03 to 0.63 ± 0.07, P = NS), with time constants of 1.5-44.6 h. Whereas the vertical distribution of relative perfusion did not change from baseline to 16 h, shunt increased in dorsal regions (0.34 ± 0.23 to 0.63 ± 0.35, P < 0.01). The average pulmonary net 18F-fluorodeoxyglucose uptake rate in six regions of interest along the ventral-dorsal direction increased from 3.4 ± 1.4·10-3min-1 at baseline to 4.1 ± 1.5·10-3min-1 after 16 h (P < 0.01), and the corresponding average regions of interest 18F-fluorodeoxyglucose phosphorylation rate increased from 2.0 ± 0.2·10-2min-1 to 2.5 ± 0.2·10-2min-1 (P < 0.01). Conclusions In normal lungs mechanically ventilated without positive end-expiratory pressure, loss of aeration occurs continuously for several hours and is preferentially localized to dorsal regions. Progressive lung derecruitment was associated with increased regional shunt, implying an insufficient hypoxic pulmonary vasoconstriction. The increased pulmonary net uptake and phosphorylation rates of 18F-fluorodeoxyglucose suggest incipient inflammation in these initially normal lungs. PMID:23535501

  18. Glutamate and GABA Imbalance Following Traumatic Brain Injury.

    PubMed

    Guerriero, Réjean M; Giza, Christopher C; Rotenberg, Alexander

    2015-05-01

    Traumatic brain injury (TBI) leads to multiple short- and long-term changes in neuronal circuits that ultimately conclude with an imbalance of cortical excitation and inhibition. Changes in neurotransmitter concentrations, receptor populations, and specific cell survival are important contributing factors. Many of these changes occur gradually, which may explain the vulnerability of the brain to multiple mild impacts, alterations in neuroplasticity, and delays in the presentation of posttraumatic epilepsy. In this review, we provide an overview of normal glutamate and GABA homeostasis and describe acute, subacute, and chronic changes that follow injury. We conclude by highlighting opportunities for therapeutic interventions in this paradigm. PMID:25796572

  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. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 2010-10-01 false Ventilation for closed spaces. 92.15-10 Section...MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 46 CFR 154.1205 - Mechanical ventilation system: Standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Mechanical ventilation system: Standards. 154.1205 Section...and Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each...

  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. Commissioning Residential Ventilation Systems: A Combined Assessment of

    E-print Network

    Commissioning Residential Ventilation Systems: A Combined Assessment of Energy and Air Quality ventilation systems are being installed in new California homes. Few measurements are available of commissioning residential whole- house ventilation systems that are intended to comply

  13. 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...

  14. 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...

  15. 14 CFR 27.1187 - Ventilation and drainage.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 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....

  16. 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...

  17. 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...

  18. 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...

  19. 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....

  20. 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...

  1. 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 §...

  2. HVAC EFFICIENCY BUSINESS CASE DEMAND CONTROL KITCHEN VENTILATION

    E-print Network

    California at Davis, University of

    HVAC EFFICIENCY BUSINESS CASE DEMAND CONTROL KITCHEN VENTILATION Selecting, financing ventilation (DCKV) for kitchen exhaust hoods. Implementation can be relatively simple in either new of demand control kitchen ventilation (DCKV) in many small, medium, and large kitchen exhaust hood

  3. RESEARCH ARTICLE Open Access Noninvasive ventilation reduces energy

    E-print Network

    Paris-Sud XI, Université de

    RESEARCH ARTICLE Open Access Noninvasive ventilation reduces energy expenditure in amyotrophic with a shift of the burden of ventilation to extradiaphragmatic inspiratory muscles, including neck muscles prognostic value. We hypothesized that noninvasive ventilation (NIV) would relieve inspiratory neck muscles

  4. Evaluation of Existing Technologies for Meeting Residential Ventilation

    E-print Network

    LBNL-59998 Evaluation of Existing Technologies for Meeting Residential Ventilation Requirements Ventilation Requirements and Distribution System Research for 2008 Building Efficiency Standards Task 3.2 Evaluation of Existing Technologies for Meeting Residential Ventilation Requirements Prepared in Support

  5. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 2012-10-01 false Ventilation for closed spaces. 92.15-10 Section...MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Mechanical ventilation system: Standards. 154.1205 Section...and Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each...

  7. 46 CFR 154.1205 - Mechanical ventilation system: Standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Mechanical ventilation system: Standards. 154.1205 Section...and Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each...

  8. 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...

  9. 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...

  10. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 2011-10-01 false Ventilation for closed spaces. 92.15-10 Section...MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except...

  11. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 2014-10-01 false Ventilation for closed spaces. 92.15-10 Section...MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except...

  12. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 2013-10-01 false Ventilation for closed spaces. 92.15-10 Section...MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  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, 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...

  19. 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...

  20. 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....

  1. 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 §...

  2. 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...

  3. 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...

  4. 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...

  5. 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....

  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. 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 §...

  8. 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...

  9. 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...

  10. 46 CFR 154.1205 - Mechanical ventilation system: Standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Mechanical ventilation system: Standards. 154.1205 Section...and Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each...

  11. 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 §...

  12. 21 CFR 868.5935 - External negative pressure ventilator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false External negative pressure ventilator. 868...Therapeutic Devices § 868.5935 External negative pressure ventilator. (a) Identification. An external negative pressure ventilator...

  13. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... false Ventilation of gasoline machinery spaces. 185.352 Section 185...185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space, required by §...

  14. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Machinery space ventilation. 111.103-3 Section...Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have...

  15. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Machinery space ventilation. 111.103-3 Section...Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Machinery space ventilation. 111.103-3 Section...Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have...

  17. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Machinery space ventilation. 111.103-3 Section...Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have...

  18. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... false Ventilation of gasoline machinery spaces. 185.352 Section 185...185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space, required by §...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... false Ventilation of gasoline machinery spaces. 185.352 Section 185...185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space, required by §...

  20. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... false Ventilation of gasoline machinery spaces. 185.352 Section 185...185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space, required by §...

  1. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Machinery space ventilation. 111.103-3 Section...Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have...

  2. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... false Ventilation of gasoline machinery spaces. 185.352 Section 185...185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space, required by §...

  3. 49 CFR 192.173 - Compressor stations: Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Compressor stations: Ventilation. 192.173 Section...of Pipeline Components § 192.173 Compressor stations: Ventilation. Each compressor station building must be ventilated to...

  4. Effects of ventilation strategy on distribution of lung inflammatory cell activity

    PubMed Central

    2013-01-01

    Introduction Leukocyte infiltration is central to the development of acute lung injury, but it is not known how mechanical ventilation strategy alters the distribution or activation of inflammatory cells. We explored how protective (vs. injurious) ventilation alters the magnitude and distribution of lung leukocyte activation following systemic endotoxin administration. Methods Anesthetized sheep received intravenous endotoxin (10 ng/kg/min) followed by 2 h of either injurious or protective mechanical ventilation (n = 6 per group). We used positron emission tomography to obtain images of regional perfusion and shunting with infused 13N[nitrogen]-saline and images of neutrophilic inflammation with 18F-fluorodeoxyglucose (18F-FDG). The Sokoloff model was used to quantify 18F-FDG uptake (Ki), as well as its components: the phosphorylation rate (k3, a surrogate of hexokinase activity) and the distribution volume of 18F-FDG (Fe) as a fraction of lung volume (Ki = Fe × k3). Regional gas fractions (fgas) were assessed by examining transmission scans. Results Before endotoxin administration, protective (vs. injurious) ventilation was associated with a higher ratio of partial pressure of oxygen in arterial blood to fraction of inspired oxygen (PaO2/FiO2) (351 ± 117 vs. 255 ± 74 mmHg; P < 0.01) and higher whole-lung fgas (0.71 ± 0.12 vs. 0.48 ± 0.08; P = 0.004), as well as, in dependent regions, lower shunt fractions. Following 2 h of endotoxemia, PaO2/FiO2 ratios decreased in both groups, but more so with injurious ventilation, which also increased the shunt fraction in dependent lung. Protective ventilation resulted in less nonaerated lung (20-fold; P < 0.01) and more normally aerated lung (14-fold; P < 0.01). Ki was lower during protective (vs. injurious) ventilation, especially in dependent lung regions (0.0075 ± 0.0043/min vs. 0.0157 ± 0.0072/min; P < 0.01). 18F-FDG phosphorylation rate (k3) was twofold higher with injurious ventilation and accounted for most of the between-group difference in Ki. Dependent regions of the protective ventilation group exhibited lower k3 values per neutrophil than those in the injurious ventilation group (P = 0.01). In contrast, Fe was not affected by ventilation strategy (P = 0.52). Lung neutrophil counts were not different between groups, even when regional inflation was accounted for. Conclusions During systemic endotoxemia, protective ventilation may reduce the magnitude and heterogeneity of pulmonary inflammatory cell metabolic activity in early lung injury and may improve gas exchange through its effects predominantly in dependent lung regions. Such effects are likely related to a reduction in the metabolic activity, but not in the number, of lung-infiltrating neutrophils. PMID:23947920

  5. 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.

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

    SciTech Connect

    Liu, Xiaobing [ORNL] [ORNL

    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. Guidelines for choosing face ventilation systems

    SciTech Connect

    Divers, E.F.; Volkwein, J.C.

    1987-10-01

    The authors discuss two machine-mounted face ventilation systems, a fan-powered dust scrubber and a sprayfan, for controlling dust and methane and increasing production by extending the cutting time of continuous miners. The systems are compared for a variety of considerations: installation and maintenance costs, ventilation, seam conditions, and dust control. Guidelines are given for the best use of each system.

  8. Demand Controlled Ventilation for Improved Humidity Control

    E-print Network

    Rogers, J. K.

    1996-01-01

    " the buildmg ventilation. The AIRxpert system does this by sending a signal to the building's energy management system (EMS) telling it when a zone is not adequately ventilated and needs more outside air. The EMS then takes the necessary action to get more...

  9. 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.

  10. New modes of assisted mechanical ventilation.

    PubMed

    Suarez-Sipmann, F

    2014-05-01

    Recent major advances in mechanical ventilation have resulted in new exciting modes of assisted ventilation. Compared to traditional ventilation modes such as assisted-controlled ventilation or pressure support ventilation, these new modes offer a number of physiological advantages derived from the improved patient control over the ventilator. By implementing advanced closed-loop control systems and using information on lung mechanics, respiratory muscle function and respiratory drive, these modes are specifically designed to improve patient-ventilator synchrony and reduce the work of breathing. Depending on their specific operational characteristics, these modes can assist spontaneous breathing efforts synchronically in time and magnitude, adapt to changing patient demands, implement automated weaning protocols, and introduce a more physiological variability in the breathing pattern. Clinicians have now the possibility to individualize and optimize ventilatory assistance during the complex transition from fully controlled to spontaneous assisted ventilation. The growing evidence of the physiological and clinical benefits of these new modes is favoring their progressive introduction into clinical practice. Future clinical trials should improve our understanding of these modes and help determine whether the claimed benefits result in better outcomes. PMID:24507472

  11. Clinical review: Liberation from mechanical ventilation

    Microsoft Academic Search

    Mohamad F El-Khatib; Pierre Bou-Khalil

    2008-01-01

    Mechanical ventilation is the defining event of intensive care unit (ICU) management. Although it is a life saving intervention in patients with acute respiratory failure and other disease entities, a major goal of critical care clinicians should be to liberate patients from mechanical ventilation as early as possible to avoid the multitude of complications and risks associated with prolonged unnecessary

  12. 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.

  13. 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.

  14. Clinical review: Long-term noninvasive ventilation

    Microsoft Academic Search

    Dominique Robert; Laurent Argaud

    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

  15. Mechanical Ventilation and the Kidney

    PubMed Central

    Koyner, Jay L.; Murray, Patrick T.

    2010-01-01

    Acute lung injury (ALI) and acute kidney injury (AKI) are complications often encountered in the setting of critical illness. Both forms of end-organ injury commonly occur in similar settings of systemic inflammatory response syndrome, shock, and evolving multiple organ dysfunction. Recent elucidation of the pathobiology of critical illness has led to a more basic mechanistic understanding of the complex interplay between injured organs in patients with multiple organ dysfunction syndrome; this has been aptly called ‘the slippery slope of critical illness’ [Kidney Int Suppl 1998;66:S25–S33]. Distant organ effects of apparently isolated injuries to the lungs, gut, and kidneys have all been discovered in recent years. In this article, we will review the harmful bidirectional interaction between ALI and AKI, which appears to be a common clinical syndrome with routine clinical implications. We will review the current understanding of lung-kidney interactions from both perspectives, including the renal effects of ALI and mechanical ventilation, and the pulmonary sequelae of AKI. In this review of the emerging evidence of deleterious bidirectional organ cross talk between lung and kidney, we will focus on the role of ventilator-induced kidney injury in the pathogenesis of AKI in patients with ALI. PMID:19923815

  16. Unusual applications of noninvasive ventilation.

    PubMed

    Ambrosino, N; Guarracino, F

    2011-08-01

    The use of noninvasive ventilation (NIV) in acute hypercapnic respiratory failure, cardiogenic pulmonary oedema, acute lung injury/acute respiratory distress syndrome (ARDS), community-acquired pneumonia and weaning/post-extubation failure is considered common in clinical practice. Herein, we review the use of NIV in unusual conditions. Evidence supports the use of NIV during fibreoptic bronchoscopy, especially with high risks of endotracheal intubation (ETI), such as in immunocompromised patients. During transoesophageal echocardiography as well as in interventional cardiology and pulmonology, NIV can reduce the need for deep sedation or general anaesthesia and prevent respiratory depression induced by deep sedation. NIV may be useful after surgery, including cardiac surgery, and, with a lower level of evidence, in patients with pulmonary contusion. NIV should not be considered as an alternative to ETI in severe communicable airborne infections likely to progress to ARDS. NIV is being used increasingly as an alternative to ETI in end-stage symptomatic patients, especially to relieve dyspnoea. The role of assisted ventilation during exercise training in chronic obstructive pulmonary disease patients is still controversial. NIV should be applied under close monitoring and ETI should be promptly available in the case of failure. A trained team, careful patient selection and optimal choice of devices, can optimise outcome of NIV. PMID:21349915

  17. 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

  18. Perfused phantom models of microwave irradiated tissue.

    PubMed

    Baish, J W; Foster, K R; Ayyaswamy, P S

    1986-08-01

    The theoretical basis, practical design considerations, and prototype testing of a perfused model suitable for simulation studies of microwave heated tissue are presented. A parallel tube heat exchanger configuration is used to simulate the internal convection effects of blood flow. The global thermal response of the phantom, on a scale of several tube spacings, is shown theoretically to be nearly identical to that predicted by Pennes' bioheat equation, which is known to give a reasonable representation of tissue under many conditions. A parametric study is provided for the relationships between the tube size, spacing and material properties and the simulated perfusion rate. A prototype with a physiologically reasonable perfusion rate was tested using a typical hyperthermia applicator. The measured thermal response of the phantom compares favorably with the numerical solution of the bioheat equation under the same irradiation conditions. This similarity sheds light on the unexpected success of the bioheat equation for modeling the thermal response of real tissue. PMID:3747467

  19. Imbalance Fault Detection of Direct-Drive Wind Turbines Using Generator Current Signals

    Microsoft Academic Search

    Xiang Gong; Wei Qiao

    2012-01-01

    Imbalance faults constitute a significant portion of all faults in wind turbine generators (WTGs). WTG imbalance fault detection using generator current measurements has advantages over traditional vibration-based methods in terms of cost, implementation, and system reliability. However, there are challenges in using current signals for imbalance fault detection due to low signal-to-noise ratio of the useful information in current signals

  20. Myocardial perfusion scintigraphy: the evidence

    PubMed Central

    Anagnostopoulos, C.; Cerqueira, M.; Ell, P. J.; Flint, E. J.; Harbinson, M.; Kelion, A. D.; Al-Mohammad, A.; Prvulovich, E. M.; Shaw, L. J.; Tweddel, A. C.

    2003-01-01

    This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by comparison with the numbers of revascularisations and coronary angiograms performed. Furthermore, MPS activity levels in this country fall far short of those in comparable European countries, with about half as many scans being undertaken per year. Currently, the number of MPS studies performed annually in the UK is 1,200/million population/year. We estimate the real need to be 4,000/million/year. The current average waiting time is 20 weeks and we recommend that clinically appropriate upper limits of waiting time are 6 weeks for routine studies and 1 week for urgent studies. PMID:15129710

  1. Improved spray fans provide ventilation solutions

    SciTech Connect

    Ruggieri, S.K.; Doyle, D.M.; Volkwein, J.C.

    1984-04-01

    The Sprayfan System is an auxiliary ventilation system. It consists of several spray manifolds strategically placed on continuous miners to effectively ventilate the immediate face area. A series of water sprays redirect the main ventilation flow to the face and sweep contaminated air (methane and dust) across the face toward the return. This improved system provides increased sweeping power across the face with a new front spray bar configuration and concentrated side power for effective face ventilation. Additional water sprays have been incorporated into the design for improved dust suppression. As with the original system, a dual-sided system is required on sections with ventilation returns on either side. To ensure proper operation, the Improved Sprayfan System requires a minimum operating pressure of 80 psi (measured at the nozzle) for most applications. Different pressure levels may be necessary to balance system power with the primary air-flow.

  2. 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.

  3. Original article Perfusion of trout liver in situ.

    E-print Network

    Paris-Sud XI, Université de

    the intermediate metabolism of fish. rainbow trout / method / liver perfusion / fish / perfusion medium Résumé it possible to study hepatic metabolism in the whole organ. Rainbow trout (Oncorhynchus mykiss Walbaum, 1986). The first studies using liver perfusion in fish date from the end of the 1960s. Pequin

  4. Optimized retrograde cerebral perfusion reduces ischemic energy depletion

    Microsoft Academic Search

    Teiji Oda; Tetsuhiro Kimura; Yoshitaka Ogata; Yutaka Fujise

    2004-01-01

    It has been reported that retrograde cerebral perfusion (RCP) provides minimal capillary flow; however, the extent to which RCP can provide aerobic metabolic support is unknown. We evaluated whether perfusate composition optimization for RCP would preserve brain energy metabolism during hypothermic circulatory arrest (HCA) at 20°C in rats. Three types of perfusates were prepared: hemoglobin-free saline, rat red blood cells,

  5. Common-path Fourier domain optical coherence tomography of irradiated human skin and ventilated isolated rabbit lungs

    NASA Astrophysics Data System (ADS)

    Popp, A.; Wendel, M.; Knels, L.; Knuschke, P.; Mehner, M.; Koch, T.; Boller, D.; Koch, P.; Koch, E.

    2005-08-01

    A compact common path Fourier domain optical coherence tomography (FD-OCT) system based on a broadband superluminescence diode is used for biomedical imaging. The epidermal thickening of human skin after exposure to ultraviolet radiation is measured to proof the feasibility of FD-OCT for future substitution of invasive biopsies in a long term study on natural UV skin protection. The FD-OCT system is also used for imaging lung parenchyma. FD-OCT images of a formalin fixated lung show the same alveolar structure as scanning electron microscopy images. In the ventilated and blood-free perfused isolated rabbit lung FD-OCT is used for real-time cross-sectional image capture of alveolar mechanics throughout tidal ventilation. The alveolar mechanics changing from alternating recruitment-derecruitment at zero positive end-expiratory pressure (PEEP) to persistent recruitment after applying a PEEP of 5 cm H2O is observed in the OCT images.

  6. Asynchronicity of facial blood perfusion in migraine.

    PubMed

    Zaproudina, Nina; Teplov, Victor; Nippolainen, Ervin; Lipponen, Jukka A; Kamshilin, Alexei A; Närhi, Matti; Karjalainen, Pasi A; Giniatullin, Rashid

    2013-01-01

    Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI) technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology. PMID:24324592

  7. Nuclear cardiology: Myocardial perfusion and function

    SciTech Connect

    Seldin, D.W. (Lahey Clinic Medical Center, Burlington, MA (United States))

    1991-08-01

    Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical; two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references.

  8. A case of myotonic dystrophy with electrolyte imbalance.

    PubMed

    Ko, Weon-Jin; Kim, Kwang-Yeol; Kim, So-Mi; Hong, Seung-Jae; Lee, Sang-Hoon; Song, Ran; Yang, Hyung-In; Lee, Yeon-Ah

    2013-07-01

    Type 1 myotonic dystrophy (DM1) is an autosomal-dominant inherited disorder with a multisystem involvement, caused by an abnormal expansion of the CTG sequence of the dystrophic myotonia protein kinase (DMPK) gene. DM1 is a variable multisystem disorder with muscular and nonmuscular abnormalities. Increasingly, endocrine abnormalities, such as gonadal, pancreatic, and adrenal dysfunction are being reported. But, Electrolytes imbalance is a very rare condition in patients with DM1 yet. Herein we present a 42-yr-old Korean male of DM1 with abnormally elevated serum sodium and potassium. The patient had minimum volume of maximally concentrated urine without water loss. It was only cured by normal saline hydration. The cause of hypernatremia was considered by primary hypodipsia. Hyperkalemic conditions such as renal failure, pseudohyperkalemia, cortisol deficiency and hyperkalemic periodic paralysis were excluded. Further endocrine evaluation suggested selective hyperreninemic hypoaldosteronism as a cause of hyperkalemia. PMID:23853500

  9. A Case of Myotonic Dystrophy with Electrolyte Imbalance

    PubMed Central

    Ko, Weon-Jin; Kim, Kwang-Yeol; Kim, So-Mi; Hong, Seung-Jae; Lee, Sang-Hoon; Song, Ran; Yang, Hyung-In

    2013-01-01

    Type 1 myotonic dystrophy (DM1) is an autosomal-dominant inherited disorder with a multisystem involvement, caused by an abnormal expansion of the CTG sequence of the dystrophic myotonia protein kinase (DMPK) gene. DM1 is a variable multisystem disorder with muscular and nonmuscular abnormalities. Increasingly, endocrine abnormalities, such as gonadal, pancreatic, and adrenal dysfunction are being reported. But, Electrolytes imbalance is a very rare condition in patients with DM1 yet. Herein we present a 42-yr-old Korean male of DM1 with abnormally elevated serum sodium and potassium. The patient had minimum volume of maximally concentrated urine without water loss. It was only cured by normal saline hydration. The cause of hypernatremia was considered by primary hypodipsia. Hyperkalemic conditions such as renal failure, pseudohyperkalemia, cortisol deficiency and hyperkalemic periodic paralysis were excluded. Further endocrine evaluation suggested selective hyperreninemic hypoaldosteronism as a cause of hyperkalemia. PMID:23853500

  10. 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

  11. Is copper imbalance an environmental factor influencing keratoconus development?

    PubMed

    Dudakova, L; Liskova, P; Jirsova, K

    2015-05-01

    Keratoconus is a bilateral disease characterized by progressive corneal thinning leading to irregular astigmatism that results in significant visual impairment. Despite extensive research, the exact etiopathogenesis of keratoconus remains unknown. Many copper-dependent enzymes such as superoxide dismutases, cytochrome c oxidase and lysyl oxidase have been shown to be altered in keratoconic corneas, and a decrease of copper levels in the diseased tissue has been reported as well. We propose a hypothesis linking all the putative pathways of keratoconus development and suggest that copper imbalance in corneal tissue may be an independent risk factor for the disease. The assessment of copper levels and its distribution in keratoconic corneas warrants further investigation. PMID:25758858

  12. Order imbalance and stock returns: Evidence from China

    E-print Network

    Shenoy, Catherine

    2007-01-01

    of the Chinese stock markets that may affect the order imbalance-return relation. Section 3 describes the data. Section 4 presents the results of the analyses. Section 5 concludes. Since this paper is the first to 1 Regulations on price limits vary across time..., YJ. Zhang / The Quarterly Review of Economics and Finance 47 (2007) 637-650 0 CD en O 'IT C , CD r- 0 -C C \\ r-ý 't 01 S0 N C0ON 0c 0cen'0 M Ln 0 0 W) 0Ci( N N Mc CM W r 0 M~ Z DW )-tý Uc n M M0N I tC >0 r 01 m r Cr-o 4ý ~ inCl0 Cq cc > i' M .6 - >l...

  13. 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.

  14. 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.

  15. Heterogeneity of Myocardial Perfusion Provides the Physiological Basis of Perfusable Tissue Index

    Microsoft Academic Search

    Pilar Herrero; Anton Staudenherz; John F. Walsh; Robert J. Gropler; Steven R. Bergmann

    1995-01-01

    Assessment of viable from nonviable myocardium is critical for the care of patients being considered for revascularization pro cedures. Recently, the perfusable tissue index (PTI) has been proposed as an index of myocardial viability. Methods: Com puter simulations were performed for homogeneously and het- erogeneously perfused tissue over a wide range of flows (0.04- 6.4 ml\\/g\\/min) using both bolus and

  16. Basic surgical techniques in the Göttingen minipig: intubation, bladder catheterization, femoral vessel catheterization, and transcardial perfusion.

    PubMed

    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 infections(6). Transcardial perfusion is the most effective fixation method, and yields preeminent results when preparing minipig organs for histology and histochemistry(2,9). 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.com(10). For extensive information about porcine anatomy we refer to Nickel et al. Vol. 1-5(11). PMID:21730947

  17. "Molecular rulers" for calibrating phenotypic effects of telomere imbalance

    PubMed Central

    Martin, C; Waggoner, D; Wong, A; Uhrig, S; Roseberry, J; Hedrick, J; Pack, S; Russell, K; Zackai, E; Dobyns, W; Ledbetter, D

    2002-01-01

    As a result of the increasing use of genome wide telomere screening, it has become evident that a significant proportion of people with idiopathic mental retardation have subtle abnormalities involving the telomeres of human chromosomes. However, during the course of these studies, there have also been telomeric imbalances identified in normal people that are not associated with any apparent phenotype. We have begun to scrutinise cases from both of these groups by determining the extent of the duplication or deletion associated with the imbalance. Five cases were examined where the telomere rearrangement resulted in trisomy for the 16p telomere. The size of the trisomic segment ranged from ?4-7 Mb and the phenotype included mental and growth retardation, brain malformations, heart defects, cleft palate, pancreatic insufficiency, genitourinary abnormalities, and dysmorphic features. Three cases with telomeric deletions without apparent phenotypic effects were also examined, one from 10q and two from 17p. All three deletions were inherited from a phenotypically normal parent carrying the same deletion, thus without apparent phenotypic effect. The largest deletion among these cases was ?600 kb on 17p. Similar studies are necessary for all telomeric regions to differentiate between those telomeric rearrangements that are pathogenic and those that are benign variants. Towards this goal, we are developing "molecular rulers" that incorporate multiple clones at each telomere that span the most distal 5 Mb region. While telomere screening has enabled the identification of telomere rearrangements, the use of molecular rulers will allow better phenotype prediction and prognosis related to these findings. PMID:12362030

  18. 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.

  19. Characteristics of coal mine ventilation air flows.

    PubMed

    Su, Shi; Chen, Hongwei; Teakle, Philip; Xue, Sheng

    2008-01-01

    Coal mine methane (CMM) is not only a greenhouse gas but also a wasted energy resource if not utilised. Underground coal mining is by far the most important source of fugitive methane emissions, and approximately 70% of all coal mining related methane is emitted to the atmosphere through mine ventilation air. Therefore, research and development on mine methane mitigation and utilisation now focuses on methane emitted from underground coal mines, in particular ventilation air methane (VAM) capture and utilisation. To date, most work has focused on the oxidation of very low concentration methane. These processes may be classified based on their combustion kinetic mechanisms into thermal oxidation and catalytic oxidation. VAM mitigation/utilisation technologies are generally divided into two basic categories: ancillary uses and principal uses. However, it is possible that the characteristics of ventilation air flows, for example the variations in methane concentration and the presence of certain compounds, which have not been reported so far, could make some potential VAM mitigation and utilisation technologies unfeasible if they cannot cope with the characteristics of mine site ventilation air flows. Therefore, it is important to understand the characteristics of mine ventilation air flows. Moreover, dust, hydrogen sulphide, sulphur dioxide, and other possible compounds emitted through mine ventilation air into the atmosphere are also pollutants. Therefore, this paper presents mine-site experimental results on the characteristics of mine ventilation air flows, including methane concentration and its variations, dust loadings, particle size, mineral matter of the dust, and other compounds in the ventilation air flows. The paper also discusses possible correlations between ventilation air characteristics and underground mining activities. PMID:17239518

  20. 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.

  1. An evaluation of Technegas as a ventilation agent compared with krypton-81 m in the scintigraphic diagnosis of pulmonary embolism.

    PubMed

    Cook, G; Clarke, S E

    1992-01-01

    A ventilation agent that provides good quality lung images, which is cheap, easy to use and non-toxic, with a low radiation dose, has long been sought. Technegas, an ultrafine aerosol of technetium-99m-labelled carbon, was developed with these qualities in mind. We have studied Technegas in a clinical setting to evaluate some of these qualities. Twenty-five patients referred with a diagnosis of suspected pulmonary embolism were investigated during the same study using both krypton-81 m and Technegas as ventilation agents in conjunction with 99mTc-macroaggregated albumin as a perfusion agent. Technegas provided images which were of satisfactory quality. Images were obtained relatively easily and without discomfort to the patient, and Technegas has the advantage of always being available. A semi-quantitative regional assessment was employed which showed a good correlation (r = 0.499, P less than 0.001) between Technegas and krypton-81 m ventilation. We report on an effect not previously found to be significant, that is lung regions were better ventilated with Technegas than with krypton-81 m. This altered the diagnostic probability rating of pulmonary embolism in a number of patients (n = 3, 12%) compared with krypton-81 m. This effect was also noted in a further 8 patients (32%) without a change in the diagnostic probability. We offer possible explanations for this phenomenon. PMID:1327796

  2. The Albany Medical College Ventilator Walker.

    PubMed

    Smith, T; Forrest, G; Evans, G; Johnson, R K; Chandler, N

    1996-12-01

    This report describes the design and use of a wheeled walker that can accommodate a ventilator and oxygen tanks. It is constructed of aluminum tubing. The front of the walker has receptacles to support a Mark 7 Bird Ventilator and oxygen tanks. The back end of the walker has a bench seat that is lifted to allow entry into the walker. The seat provides rigidity and stability to the frame of the walker. The walker has been used in the Medical Intensive Care Unit of the Albany Medical Center to facilitate early ambulation of patients who are ventilator dependent or who require a portable source of oxygen to begin ambulation training. PMID:8976320

  3. Position paper - primary ventilation system configuration

    SciTech Connect

    Dalpiaz, E.L.

    1994-06-01

    The purpose of this paper is to develop and document a position on the configuration of the primary ventilation system. This configuration will be used on the waste storage tanks currently being designed for the Multi-Function Waste Tank Facility. The primary ventilation system provides a single treatment train and exhaust fan for each waste storage tank. The ventilation systems from each of two tanks are grouped with an additional treatment train and exhaust fan that function as backup to either of the two systems.

  4. How to choose an anesthesia ventilator?

    PubMed

    Coisel, Y; Millot, A; Carr, J; Castagnoli, A; Pouzeratte, Y; Verzilli, D; Futier, E; Jaber, S

    2014-01-01

    During the past few years, many manufacturers have developed a new generation anesthesia ventilators or anesthesia workstations with innovative technology and introduced so-called new ventilatory modes in the operating room. The aim of this article is to briefly explain how an anesthesia ventilator works, to describe the main differences between the technologies used, to describe the main criteria for evaluating technical and pneumatic performances and to list key elements not to be forgotten during the process of acquiring an anesthesia ventilator. PMID:25138358

  5. Secretion management in the mechanically ventilated patient.

    PubMed

    Branson, Richard D

    2007-10-01

    Secretion management in the mechanically ventilated patient includes routine methods for maintaining mucociliary function, as well as techniques for secretion removal. Humidification, mobilization of the patient, and airway suctioning are all routine procedures for managing secretions in the ventilated patient. Early ambulation of the post-surgical patient and routine turning of the ventilated patient are common secretion-management techniques that have little supporting evidence of efficacy. Humidification is a standard of care and a requisite for secretion management. Both active and passive humidification can be used. The humidifier selected and the level of humidification required depend on the patient's condition and the expected duration of intubation. In patients with thick, copious secretions, heated humidification is superior to a heat and moisture exchanger. Airway suctioning is the most important secretion removal technique. Open-circuit and closed-circuit suctioning have similar efficacy. Instilling saline prior to suctioning, to thin the secretions or stimulate a cough, is not supported by the literature. Adequate humidification and as-needed suctioning are the foundation of secretion management in the mechanically ventilated patient. Intermittent therapy for secretion removal includes techniques either to simulate a cough, to mechanically loosen secretions, or both. Patient positioning for secretion drainage is also widely used. Percussion and postural drainage have been widely employed for mechanically ventilated patients but have not been shown to reduce ventilator-associated pneumonia or atelectasis. Manual hyperinflation and insufflation-exsufflation, which attempt to improve secretion removal by simulating a cough, have been described in mechanically ventilated patients, but neither has been studied sufficiently to support routine use. Continuous lateral rotation with a specialized bed reduces atelectasis in some patients, but has not been shown to improve secretion removal. Intrapulmonary percussive ventilation combines percussion with hyperinflation and a simulated cough, but the evidence for intrapulmonary percussive ventilation in mechanically ventilated patients is insufficient to support routine use. Secretion management in the mechanically ventilated patient consists of appropriate humidification and as-needed airway suctioning. Intermittent techniques may play a role when secretion retention persists despite adequate humidification and suctioning. The technique selected should remedy the suspected etiology of the secretion retention (eg, insufflation-exsufflation for impaired cough). Further research into secretion management in the mechanically ventilated patient is needed. PMID:17894902

  6. Measuring Residential Ventilation System Airflows: Part 1 Laboratory

    E-print Network

    1 Measuring Residential Ventilation System Airflows: Part 1 ­ Laboratory Evaluation of Airflow: residential, mechanical ventilation, measurement, ASHRAE 62.2, flow hood ABSTRACT Building codes increasingly require tighter homes and mechanical ventilation per ASHRAE Standard 62.2. These ventilation flows must

  7. 30 CFR 77.1911 - Ventilation of slopes and shafts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 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....

  8. 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....

  9. 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

  10. 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....

  11. 30 CFR 77.1911 - Ventilation of slopes and shafts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 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....

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

    E-print Network

    Lewis, Mark

    THE MECHANICS OF LUNG TISSUE UNDER HIGH-FREQUENCY VENTILATION MARKUS R. OWEN AND MARK A. LEWIS SIAM­1761 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

  13. Assessing Data Quality in Manual Entry of Ventilator Settings

    Microsoft Academic Search

    DAVID K. VAWDREY; REED M. GARDNER; R. SCOTT EVANS; JAMES F. ORME; TERRY P. CLEMMER; LOREN GREENWAY; FRANK A. DREWS

    2010-01-01

    Objective: To evaluate the data quality of ventilator settings recorded by respiratory therapists using a computer charting application and assess the impact of incorrect data on computerized ventilator management protocols. Design: An analysis of 29,054 charting events gathered over 12 months from 678 ventilated patients (1,736 ventilator days) in four intensive care units at a tertiary care hospital. Measurements: Ten

  14. 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…

  15. Global Imbalances and the U.S. Trade Deficit Robert A. Blecker

    E-print Network

    Carlini, David

    Global Imbalances and the U.S. Trade Deficit Robert A. Blecker1 As the U.S. and foreign economies slowly, this chapter argues that the U.S. trade deficit and foreign trade surpluses were at least a contributing factorGlobal Imbalances and the U.S. Trade Deficit Robert A. Blecker Department of Economics American

  16. Lung perfusion imaging in small animals using 4D micro-CT at heartbeat temporal resolution

    PubMed Central

    Badea, Cristian T.; Johnston, Samuel M.; Subashi, Ergys; Qi, Yi; Hedlund, Laurence W.; Johnson, G. Allan

    2010-01-01

    Purpose: Quantitative in vivo imaging of lung perfusion in rodents can provide critical information for preclinical studies. However, the combined challenges of high temporal and spatial resolution have made routine quantitative perfusion imaging difficult in small animals. The purpose of this work is to demonstrate 4D micro-CT for perfusion imaging in rodents at heartbeat temporal resolution and isotropic spatial resolution. Methods: We have recently developed a dual tube?detector micro-CT scanner that is well suited to capture first pass kinetics of a bolus of contrast agent used to compute perfusion information. Our approach is based on the paradigm that similar time density curves can be reproduced in a number of consecutive, small volume injections of iodinated contrast agent at a series of different angles. This reproducibility is ensured by the high-level integration of the imaging components of our system with a microinjector, a mechanical ventilator, and monitoring applications. Sampling is controlled through a biological pulse sequence implemented in LABVIEW. Image reconstruction is based on a simultaneous algebraic reconstruction technique implemented on a graphic processor unit. The capabilities of 4D micro-CT imaging are demonstrated in studies on lung perfusion in rats. Results: We report 4D micro-CT imaging in the rat lung with a heartbeat temporal resolution (approximately 150 ms) and isotropic 3D reconstruction with a voxel size of 88 ?m based on sampling using 16 injections of 50 ?L each. The total volume of contrast agent injected during the experiments (0.8 mL) was less than 10% of the total blood volume in a rat. This volume was not injected in a single bolus, but in multiple injections separated by at least 2 min interval to allow for clearance and adaptation. We assessed the reproducibility of the time density curves with multiple injections and found that these are very similar. The average time density curves for the first eight and last eight injections are slightly different, i.e., for the last eight injections, both the maximum of the average time density curves and its area under the curve are decreased by 3.8% and 7.2%, respectively, relative to the average time density curves based on the first eight injections. The radiation dose associated with our 4D micro-CT imaging is 0.16 Gy and is therefore in the range of a typical micro-CT dose. Conclusions: 4D micro-CT-based perfusion imaging demonstrated here has immediate application in a wide range of preclinical studies such as tumor perfusion, angiogenesis, and renal function. Although our imaging system is in many ways unique, we believe that our approach based on the multiple injection paradigm can be used with the newly developed flat-panel slip-ring-based micro-CT to increase their temporal resolution in dynamic perfusion studies. PMID:20175466

  17. Carbon Dioxide and Oxygen Levels in Disposable Individually Ventilated Cages after Removal from Mechanical Ventilation

    PubMed Central

    Nagamine, Claude M; Long, C Tyler; McKeon, Gabriel P; Felt, Stephen A

    2012-01-01

    Disposable individually ventilated cages have lids that restrict air exchange when the cage is not mechanically ventilated. This design feature may cause intracage CO2 to increase and O2 to decrease (hypercapnic and hypoxic conditions, respectively) when the electrical supply to the ventilated rack fails, the ventilated rack malfunctions, cages are docked in the rack incorrectly, or cages are removed from the ventilated rack for extended periods of time. We investigated how quickly hypercapnic and hypoxic conditions developed within disposable individually ventilated cages after removal from mechanical ventilation and compared the data with nondisposable static cages, disposable static cages, and unventilated nondisposable individually ventilated cages. When disposable individually ventilated cages with 5 adult mice per cage were removed from mechanical ventilation, CO2 concentrations increased from less than 1% at 0 h to approximately 5% at 3 h and O2 levels dropped from more than 20% at 0 h to 11.7% at 6 h. The breathing pattern of the mice showed a prominent abdominal component (hyperventilation). Changes were similar for 4 adult mice per cage, reaching at least 5% CO2 at 4 h and 13.0% O2 at 6 h. For 3 or 2 mice per cage, values were 4.6% CO2 and 14.7% O2 and 3.04% CO2 and 17.1% O2, respectively, at 6 h. These results document that within disposable individually ventilated cages, a hypercapnic and hypoxic microenvironment develops within hours in the absence of mechanical ventilation. PMID:22776114

  18. Effects of a chemical imbalance causal explanation on individuals' perceptions of their depressive symptoms.

    PubMed

    Kemp, Joshua J; Lickel, James J; Deacon, Brett J

    2014-05-01

    Although the chemical imbalance theory is the dominant causal explanation of depression in the United States, little is known about the effects of this explanation on depressed individuals. This experiment examined the impact of chemical imbalance test feedback on perceptions of stigma, prognosis, negative mood regulation expectancies, and treatment credibility and expectancy. Participants endorsing a past or current depressive episode received results of a bogus but credible biological test demonstrating their depressive symptoms to be caused, or not caused, by a chemical imbalance in the brain. Results showed that chemical imbalance test feedback failed to reduce self-blame, elicited worse prognostic pessimism and negative mood regulation expectancies, and led participants to view pharmacotherapy as more credible and effective than psychotherapy. The present findings add to a growing literature highlighting the unhelpful and potentially iatrogenic effects of attributing depressive symptoms to a chemical imbalance. Clinical and societal implications of these findings are discussed. PMID:24657311

  19. 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 ...

  20. 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 multi-scale model...

  1. 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 ...

  2. 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 ...

  3. 21 CFR 868.5895 - Continuous ventilator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    21 Food and Drugs 8 2014-04-01 2014-04-01...5895 Section 868.5895 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH...neonatal ventilators are included in this generic type of device. (b)...

  4. 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 ...

  5. 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 ...

  6. Ventilation of the Baltic Sea deep water

    E-print Network

    Mohrholz, Volker

    Sea Salt water inflows Deep water ventilation Entrainment Turbulent mixing H. E. Markus Meier1, Rainer Volker Mohrholz2 Christian Nohr4 Vadim T. Paka6 J¨urgen Sellschopp5 Adolf Stips8 Victor Zhurbas7 1

  7. Machine-mounted scrubber helps ventilate face

    SciTech Connect

    Volkwein, J.C.

    1985-02-01

    The authors describe work carried out under contract for US Bureau of Mines on a machine-mounted scrubber system for ventilating the face during an extended advance. Underground tests showed that a suitable scrubber system can adequately ventilate the face at brattice setbacks up to 15m. Face methane levels were effectively controlled at large setbacks, but respirable dust levels increased by as much as 33% at the operator's cab at setbacks greater than 7.5m.

  8. Diaphragmatic Activity and Ventilation in Preterm Infants

    Microsoft Academic Search

    Francisco J. C. Reis; Donald B. Cates; Leanne V. Landriault; Henrique Rigatto

    1994-01-01

    To determine the effects of inhaled CO2 and abdominal loading on diaphragmatic electromyography (EMGdi) and ventilation during sleep, we studied 10 preterm infants (birth weight 1,840 ± 50 g; gestational age 32 ± 0.6 weeks and postnatal age 10.4 ± 1.4 days). We measured surface and esophageal diaphragmatic activity. Ventilation was measured using a nasal flowmeter and a flow-through system.

  9. Gas flow rates through transtracheal ventilation catheters

    Microsoft Academic Search

    Jonathan K Marr; Loren G Yamamoto

    2004-01-01

    The purpose of the study was to measure gas flow rates using different methods of transtracheal ventilation. Wall oxygen flow (WOF) at 10 and 15L\\/min, and a self-inflating ventilation bag (SIVB) were used to deliver gas flow through three transtracheal catheters: 13, 14, and 16 gauge (5 trials each). WOF mean gas flow rates (L\\/min) through the 16G, 14G, 13G

  10. Night ventilation control strategies in office buildings

    Microsoft Academic Search

    Zhaojun Wang; Lingli Yi; Fusheng Gao

    2009-01-01

    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

  11. Sensor-based demand controlled ventilation

    SciTech Connect

    De Almeida, A.T. [Universidade de Coimbra (Portugal). Dep. Eng. Electrotecnica; Fisk, W.J. [Lawrence Berkeley National Lab., CA (United States)

    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.

  12. Humidification of inspired gases during mechanical ventilation.

    PubMed

    Gross, J L; Park, G R

    2012-04-01

    Humidification of inspired gas is mandatory for all mechanically ventilated patients to prevent secretion retention, tracheal tube blockage and adverse changes occurring to the respiratory tract epithelium. However, the debate over "ideal" humidification continues. Several devices are available that include active and passive heat and moisture exchangers and hot water humidifiers Each have their advantages and disadvantages in mechanically ventilated patients. This review explores each device in turn and defines their role in clinical practice. PMID:22269929

  13. Recovering Energy From Ventilation and Process Airstreams

    E-print Network

    Cheney, W. A.

    RECOVERING ENERGY FROM VENTILATION AND PROCESS AIRSTREAMS Heat Exchangers and contaminant Recovery William A. Cheney united Air Specialists, Inc. Cincinnati, Ohio The high cost of energy has prompted industry to look for new ways to reduce... operating expenses. Often ignored are the large amounts of recoverable energy present in the ventilation and process airstreams discharged from the plant. The recovery methods available range from fairly simple, well-known devices that have been around...

  14. 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.

  15. Pretest Predictions for Phase II Ventilation Tests

    SciTech Connect

    Yiming Sun

    2001-09-19

    The objective of this calculation is to predict the temperatures of the ventilating air, waste package surface, and concrete pipe walls that will be developed during the Phase II ventilation tests involving various test conditions. The results will be used as inputs to validating numerical approach for modeling continuous ventilation, and be used to support the repository subsurface design. The scope of the calculation is to identify the physical mechanisms and parameters related to thermal response in the Phase II ventilation tests, and describe numerical methods that are used to calculate the effects of continuous ventilation. The calculation is limited to thermal effect only. This engineering work activity is conducted in accordance with the ''Technical Work Plan for: Subsurface Performance Testing for License Application (LA) for Fiscal Year 2001'' (CRWMS M&O 2000d). This technical work plan (TWP) includes an AP-2.21Q, ''Quality Determinations and Planning for Scientific, Engineering, and Regulatory Compliance Activities'', activity evaluation (CRWMS M&O 2000d, Addendum A) that has determined this activity is subject to the YMP quality assurance (QA) program. The calculation is developed in accordance with the AP-3.12Q procedure, ''Calculations''. Additional background information regarding this activity is contained in the ''Development Plan for Ventilation Pretest Predictive Calculation'' (DP) (CRWMS M&O 2000a).

  16. 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

  17. Body mass index contributes to sympathovagal imbalance in prehypertensives

    PubMed Central

    2012-01-01

    Background The present study was conducted to assess the nature of sympathovagal imbalance (SVI) in prehypertensives by short-term analysis of heart rate variability (HRV) to understand the alteration in autonomic modulation and the contribution of BMI to SVI in the genesis of prehypertension. Methods Body mass index (BMI), basal heart rate (BHR), blood pressure (BP), rate pressure product (RPP) and HRV indices such as total power (TP), low-frequency power (LF), normalized LF (LFnu), high-frequency power (HF), normalized HF (HFnu), LF-HF ratio, mean heart rate (mean RR), square root of the mean squared differences of successive normal to normal intervals (RMSSD), standard deviation of normal to normal RR interval (SDNN), the number of interval differences of successive NN intervals greater than 50?ms (NN50) and the proportion derived by dividing NN50 by the total number of NN intervals (pNN50) were assessed in three groups of subjects: normotensives having normal BMI (Group 1), prehypertensives having normal BMI (Group 2) and prehypertensives having higher BMI (Group 3). SVI was assessed from LF-HF ratio and correlated with BMI, BHR, BP and RPP in all the groups by Pearson correlation. The contribution of BMI to SVI was assessed by multiple regression analysis. Results LF and LFnu were significantly increased and HF and HFnu were significantly decreased in prehypertensive subjects in comparison to normotensive subjects and the magnitude of these changes was more prominent in subjects with higher BMI compared to that of normal BMI. LF-HF ratio, the sensitive indicator of sympathovagal balance had significant correlation with BMI (P?=?0.000) and diastolic blood pressure (DBP) (P?=?0.002) in prehypertensives. BMI was found to be an independent contributing factor to SVI (P?=?0.001) in prehypertensives. Conclusions It was concluded that autonomic imbalance in prehypertensives manifested in the form of increased sympathetic activity and vagal inhibition. In prehypertensives with higher BMI, vagal withdrawal was predominant than sympathetic overactivity. Magnitude of SVI (alteration in LF-HF ratio) was linked to changes in BMI and DBP. BMI had an independent influence on LF-HF ratio. It was advised that life-style modifications such as yoga and exercise would enable achieve the sympathovagal balance and blood pressure homeostasis in prehypertensives. PMID:22812583

  18. Seismic qualification of ventilation stack

    SciTech Connect

    Chen, W.W.; Huang, S.N.; Lindquist, M.R.

    1993-10-01

    This paper describes the method to be used to qualify the 105 K ventilation stack at the U.S. Department of Energy`s Hanford Site, near Richland, Washington, under seismic and wind loadings. The stack stands at 175 ft (53.34 m), with a diameter tapering from 22 ft (6.71 m) at the foundation to 12.83 ft (3.91 m) at the top. Although the stack is classified as Safety Class 3 (low hazard), it is treated as a Safety Class 1 (high hazard) component, as failure could damage a Safety Class 1 facility (the irradiated fuel storage basin). The evaluation used U.S. Department of Energy criteria specified in UCRL 15910 (1990). The seismic responses of the stack under earthquake loading were obtained from modal analyses with response spectrum input that used the ANSYS (1989) finite-element computer code. The moments and shear forces from the results of seismic analysis were used to qualify the reinforcement capacity of the stack structure by the ultimate-strength method. The wind forces acting on the stack in both along-wind and crosswind directions were also calculated. Presented are evaluations of the soil bearing pressure, the moment, and the shear capacity of the stack foundation.

  19. Injurious mechanical ventilation affects neuronal activation in ventilated rats

    PubMed Central

    2011-01-01

    Introduction Survivors of critical illness often have significant long-term brain dysfunction, and routine clinical procedures like mechanical ventilation (MV) may affect long-term brain outcome. We aimed to investigate the effect of the increase of tidal volume (Vt) on brain activation in a rat model. Methods Male Sprague Dawley rats were randomized to three groups: 1) Basal: anesthetized unventilated animals, 2) low Vt (LVt): MV for three hours with Vt 8 ml/kg and zero positive end-expiratory pressure (ZEEP), and 3) high Vt (HVt) MV for three hours with Vt 30 ml/kg and ZEEP. We measured lung mechanics, mean arterial pressure (MAP), arterial blood gases, and plasma and lung levels of cytokines. We used immunohistochemistry to examine c-fos as a marker of neuronal activation. An additional group of spontaneously breathing rats was added to discriminate the effect of surgical procedure and anesthesia in the brain. Results After three hours on LVt, PaO2 decreased and PaCO2 increased significantly. MAP and compliance remained stable in MV groups. Systemic and pulmonary inflammation was higher in MV rats than in unventilated rats. Plasma TNF? was significantly higher in HVt than in LVt. Immunopositive cells to c-fos in the retrosplenial cortex and thalamus increased significantly in HVt rats but not in LVt or unventilated rats. Conclusions MV promoted brain activation. The intensity of the response was higher in HVt animals, suggesting an iatrogenic effect of MV on the brain. These findings suggest that this novel cross-talking mechanism between the lung and the brain should be explored in patients undergoing MV. PMID:21569477

  20. Regional cerebral perfusion in cardiovascular reflex syncope

    Microsoft Academic Search

    Jari P. Töyry; Jyrki T. Kuikka; Esko A. Länsimies

    1997-01-01

    Little is known about the regional cerebral perfusion in subjects with presyncope or syncope, and the impact that autonomic\\u000a nervous dysfunction has on it. Seven subjects with cardiovascular vasodepressor reflex syncope were studied. A baseline test\\u000a was performed with the patients standing in the 70° upright position, while the passive head-up tilt table test with and without\\u000a isoprenaline infusion was

  1. Speckles in laser Doppler perfusion imaging

    NASA Astrophysics Data System (ADS)

    Rajan, V.; Varghese, B.; van Leeuwen, T. G.; Steenbergen, W.

    2006-02-01

    We report on the quantitative influence of speckles in laser Doppler perfusion imaging. The influence of speckles on the signal amplitude and on the Doppler spectrum is demonstrated experimentally for particle suspensions with different scattering levels and various beam widths. It is shown that the type of tissue affects the instrumental response through the effect of lateral light diffusion on the number of speckles involved in the detection process. These effects are largest for narrow beams.

  2. Glomerular filtration in the isolated perfused kidney

    Microsoft Academic Search

    H. M. Brink; W. M. Moons; J. F. G. Slegers

    1983-01-01

    The permeability of the glomerular capillary wall to neutral macromolecules was studied in isolated perfused rat kidneys. Pluronic F108 (BASF, Wyandotte, MI, USA), a polyoxyethylene-polyoxypropylene block copolymer of mol weight ~14,000, was used as plasma expander. Pore theory was applied to the fractional clearances of Pluronic F108 and dextran (mol weight 19,400) molecules measured both as a function of glomerular

  3. 10 CFR 429.43 - Commercial heating, ventilating, air conditioning (HVAC) equipment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Commercial heating, ventilating, air conditioning (HVAC) equipment. 429...Commercial heating, ventilating, air conditioning (HVAC) equipment. Link...commercial heating, ventilating, air conditioning (HVAC) equipment,...

  4. 10 CFR 429.43 - Commercial heating, ventilating, air conditioning (HVAC) equipment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Commercial heating, ventilating, air conditioning (HVAC) equipment. 429...Commercial heating, ventilating, air conditioning (HVAC) equipment. (a...commercial heating, ventilating, air conditioning (HVAC) equipment,...

  5. 10 CFR 429.43 - Commercial heating, ventilating, air conditioning (HVAC) equipment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Commercial heating, ventilating, air conditioning (HVAC) equipment. 429...Commercial heating, ventilating, air conditioning (HVAC) equipment. (a...commercial heating, ventilating, air conditioning (HVAC) equipment,...

  6. 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.

  7. Parallel perfusion imaging processing using GPGPU

    PubMed Central

    Zhu, Fan; Gonzalez, David Rodriguez; Carpenter, Trevor; Atkinson, Malcolm; Wardlaw, Joanna

    2012-01-01

    Background and purpose The objective of brain perfusion quantification is to generate parametric maps of relevant hemodynamic quantities such as cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) that can be used in diagnosis of acute stroke. These calculations involve deconvolution operations that can be very computationally expensive when using local Arterial Input Functions (AIF). As time is vitally important in the case of acute stroke, reducing the analysis time will reduce the number of brain cells damaged and increase the potential for recovery. Methods GPUs originated as graphics generation dedicated co-processors, but modern GPUs have evolved to become a more general processor capable of executing scientific computations. It provides a highly parallel computing environment due to its large number of computing cores and constitutes an affordable high performance computing method. In this paper, we will present the implementation of a deconvolution algorithm for brain perfusion quantification on GPGPU (General Purpose Graphics Processor Units) using the CUDA programming model. We present the serial and parallel implementations of such algorithms and the evaluation of the performance gains using GPUs. Results Our method has gained a 5.56 and 3.75 speedup for CT and MR images respectively. Conclusions It seems that using GPGPU is a desirable approach in perfusion imaging analysis, which does not harm the quality of cerebral hemodynamic maps but delivers results faster than the traditional computation. PMID:22824549

  8. Does Observation of Postural Imbalance Induce a Postural Reaction?

    PubMed Central

    Tia, Banty; Saimpont, Arnaud; Paizis, Christos; Mourey, France; Fadiga, Luciano; Pozzo, Thierry

    2011-01-01

    Background Several studies bring evidence that action observation elicits contagious responses during social interactions. However automatic imitative tendencies are generally inhibited and it remains unclear in which conditions mere action observation triggers motor behaviours. In this study, we addressed the question of contagious postural responses when observing human imbalance. Methodology/Principal Findings We recorded participants' body sway while they observed a fixation cross (control condition), an upright point-light display of a gymnast balancing on a rope, and the same point-light display presented upside down. Our results showed that, when the upright stimulus was displayed prior to the inverted one, centre of pressure area and antero-posterior path length were significantly greater in the upright condition compared to the control and upside down conditions. Conclusions/Significance These results demonstrate a contagious postural reaction suggesting a partial inefficiency of inhibitory processes. Further, kinematic information was sufficient to trigger this reaction. The difference recorded between the upright and upside down conditions indicates that the contagion effect was dependent on the integration of gravity constraints by body kinematics. Interestingly, the postural response was sensitive to habituation, and seemed to disappear when the observer was previously shown an inverted display. The motor contagion recorded here is consistent with previous work showing vegetative output during observation of an effortful movement and could indicate that lower level control facilitates contagion effects. PMID:21423622

  9. A clinical approach to common electrolyte problems: 2. Potassium imbalances.

    PubMed Central

    Bear, R. A.; Neil, G. A.

    1983-01-01

    A clinical approach to potassium imbalances is presented. Hypokalemia is rarely due solely to a reduced intake of potassium; instead, it usually results from a potassium flux into the cells or increased loss of the element, at times combined with a decreased intake. The clinician must seek the cause of the intracellular flux or the source of the gastrointestinal or renal loss. The causes of gastrointestinal losses are generally self evident. Renal potassium wasting, though, generally results from increased mineralocorticoid activity, an increased rate of urinary flow or of sodium delivery to the distal nephron, or both, hypomagnesemia or a combination of these factors. Hyperkalemia may be factitious, but usually it is caused by a flux of potassium from the cells or a decrease in the renal loss of potassium, the latter being mediated by a reduction in renal function, mineralocorticoid activity, or the rate of urinary flow or sodium delivery, or both. In both hypokalemia and hyperkalemia, treatment must be guided by the specific clinical circumstances. PMID:6344969

  10. Cardiac Angiogenic Imbalance Leads to Peri-partum Cardiomyopathy

    PubMed Central

    Patten, Ian S.; Rana, Sarosh; Shahul, Sajid; Rowe, Glenn C; Jang, Cholsoon; Liu, Laura; Hacker, Michele R.; Rhee, Julie S.; Mitchell, John; Mahmood, Feroze; Hess, Phil; Farrell, Caitlin; Koulisis, Nicole; Khankin, Eliyahu V; Burke, Suzanne D.; Tudorache, Igor; Bauersachs, Johann; del Monte, Federica; Hilfiker-Kleiner, Denise; Karumanchi, S. Ananth; Arany, Zoltan

    2012-01-01

    Peri-partum cardiomyopathy (PPCM) is a frequently fatal disease that affects women near delivery, and occurs more frequently in women with pre-eclampsia and/or multiple gestation. The etiology of PPCM, or why it associates with pre-eclampsia, remains unknown. We show here that PPCM is associated with a systemic angiogenic imbalance, accentuated by pre-eclampsia. Mice that lack cardiac PGC-1?, a powerful regulator of angiogenesis, develop profound PPCM. Importantly, the PPCM is entirely rescued by pro-angiogenic therapies. In humans, the placenta in late gestation secretes VEGF inhibitors like soluble Flt1 (sFlt1), and this is accentuated by multiple gestation and pre-eclampsia. This anti-angiogenic environment is accompanied by sub-clinical cardiac dysfunction, the extent of which correlates with circulating levels of sFlt1. Exogenous sFlt1 alone caused diastolic dysfunction in wildtype mice, and profound systolic dysfunction in mice lacking cardiac PGC-1?. Finally, plasma samples from women with PPCM contained abnormally high levels of sFlt1. These data strongly suggest that PPCM is in large part a vascular disease, caused by excess anti-angiogenic signaling in the peri-partum period. The data also explain how late pregnancy poses a threat to cardiac homeostasis, and why pre-eclampsia and multiple gestation are important risk factors for the development of PPCM. PMID:22596155

  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. 22 year cycle in the imbalance of the photospheric magnetic fluxes

    NASA Astrophysics Data System (ADS)

    Vernova, Elena; Baranov, Dmitrii; Tyasto, Marta

    The manifestation of the 22 year solar magnetic cycle in the imbalance of positive and negative photospheric magnetic fluxes is studied. For the analysis we use synoptic maps of the photospheric magnetic field of Kitt Peak Observatory (1976 - 2003) and John Wilcox Observatory in Stanford (1976 - 2012). We consider strong magnetic fields for the heliolatitudes in the interval from +40° to -40°. It is shown that the sign of the imbalance between positive and negative fluxes remains constant during 11 years from one inversion of the Sun’s global magnetic field to the next one and always coincides with the sign of the polar field in the Northern hemisphere. Thus, the imbalance between the magnetic fluxes of different polarities changes according to the 22 year cycle. The sign of the imbalance is determined both by the phase of the solar cycle (before or after the inversion) and by the parity of the solar cycle. The imbalance of positive and negative magnetic fluxes can be observed not only for the strong fields in the sunspot zone. The mean magnetic field of the Sun (Sun as a star), which is determined by the net flux of the background fields, changes according to the same pattern as the imbalance of the strong fields. The regular changes of the imbalance of the photospheric magnetic fields are reflected also in the parameters of heliosphere. We show the connection of the imbalance with the quadrupole component of the photospheric magnetic field and with the imbalance of the interplanetary magnetic field (the difference between the numbers of the days with positive and negative polarities of the interplanetary magnetic field near Earth).

  13. Episodic ventilation lowers the efficiency of pulmonary CO2 excretion.

    PubMed

    Malte, Christian Lind; Malte, Hans; Wang, Tobias

    2013-11-01

    The ventilation pattern of many ectothermic vertebrates, as well as hibernating and diving endotherms, is episodic where breaths are clustered in bouts interspersed among apneas of varying duration. Using mechanically ventilated, anesthetized freshwater turtles (Trachemys scripta), a species that normally exhibits this episodic ventilation pattern, we investigated whether episodic ventilation affects pulmonary gas exchange compared with evenly spaced breaths. In two separate series of experiments (a noninvasive and an invasive), ventilation pattern was switched from a steady state, with evenly spaced breaths, to episodic ventilation while maintaining overall minute ventilation (30 ml·min(-1)·kg(-1)). On switching to an episodic ventilation pattern of 10 clustered breaths, mean CO2 excretion rate was reduced by 6 ± 5% (noninvasive protocol) or 20 ± 8% (invasive protocol) in the first ventilation pattern cycle, along with a reduction in the respiratory exchange ratio. O2 uptake was either not affected or increased in the first ventilation pattern cycle, while neither heart rate nor overall pulmonary blood flow was significantly affected by the ventilation patterns. The results confirm that, for a given minute ventilation, episodic ventilation is intrinsically less efficient for CO2 excretion, thereby indicating an increase in the total bodily CO2 store in the protocol. Despite the apparent CO2 retention, mean arterial Pco2 only increased 1 Torr during the episodic ventilation pattern, which was concomitant with a possible reduction of respiratory quotient. This would indicate a shift in metabolism such that less CO2 is produced when the efficiency of excretion is reduced. PMID:23970538

  14. Incremental value of combined perfusion and function over perfusion alone by gated SPECT myocardial perfusion imaging for detection of severe three-vessel coronary artery disease

    Microsoft Academic Search

    Ronaldo S. L. Lima; Denny D. Watson; Allen R. Goode; Mir S. Siadaty; Michael Ragosta; George A. Beller; Habib Samady

    2003-01-01

    ObjectivesWe hypothesized that combining functional assessment to perfusion enhances the ability of electrocardiographic gating Tc-99m sestamibi single photon emission computed tomography (gated SPECT) myocardial perfusion imaging (MPI) to detect defects in multiple vascular territories in patients with severe three-vessel coronary artery disease (3VD).

  15. Regenerative Blower for EVA Suit Ventilation Fan

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Paul, Heather L.

    2010-01-01

    Portable life support systems in future space suits will include a ventilation subsystem driven by a dedicated fan. This ventilation fan must meet challenging requirements for pressure rise, flow rate, efficiency, size, safety, and reliability. This paper describes research and development that showed the feasibility of a regenerative blower that is uniquely suited to meet these requirements. We proved feasibility through component tests, blower tests, and design analysis. Based on the requirements for the Constellation Space Suit Element (CSSE) Portable Life Support System (PLSS) ventilation fan, we designed the critical elements of the blower. We measured the effects of key design parameters on blower performance using separate effects tests, and used the results of these tests to design a regenerative blower that will meet the ventilation fan requirements. We assembled a proof-of-concept blower and measured its performance at sub-atmospheric pressures that simulate a PLSS ventilation loop environment. Head/flow performance and maximum efficiency point data were used to specify the design and operating conditions for the ventilation fan. We identified materials for the blower that will enhance safety for operation in a lunar environment, and produced a solid model that illustrates the final design. The proof-of-concept blower produced the flow rate and pressure rise needed for the CSSE ventilation subsystem while running at 5400 rpm, consuming only 9 W of electric power using a non-optimized, commercial motor and controller and inefficient bearings. Scaling the test results to a complete design shows that a lightweight, compact, reliable, and low power regenerative blower can meet the performance requirements for future space suit life support systems.

  16. Ventilation efficiencies of a desk-edge-mounted task ventilation system

    SciTech Connect

    Faulkner, David; Fisk, William J.; Sullivan, Douglas P.; Lee, Seung Min

    2002-03-01

    In chamber experiments, we investigated the effectiveness of a task ventilation system with an air supply nozzle located underneath the front edge of a desk and directing air toward a heated mannequin seated at the desk. The task ventilation system provided outside air, while another ventilation system provided additional space cooling but no outside air. Test variables included the vertical angle of air supply (-15{sup o} to 45{sup o} from horizontal), and the supply flow rate of (3.5 to 6.5 L s{sup -1}). Using the tracer gas step-up and step-down procedures, the measured air change effectiveness (i.e., exhaust air age divided by age of air at the mannequin's face) ranged from 1.4 to 2.7, which is higher than typically reported for commercially available task ventilation or displacement ventilation systems.

  17. Towards robust deconvolution of low-dose perfusion CT: sparse perfusion deconvolution using online dictionary learning.

    PubMed

    Fang, Ruogu; Chen, Tsuhan; Sanelli, Pina C

    2013-05-01

    Computed tomography perfusion (CTP) is an important functional imaging modality in the evaluation of cerebrovascular diseases, particularly in acute stroke and vasospasm. However, the post-processed parametric maps of blood flow tend to be noisy, especially in low-dose CTP, due to the noisy contrast enhancement profile and the oscillatory nature of the results generated by the current computational methods. In this paper, we propose a robust sparse perfusion deconvolution method (SPD) to estimate cerebral blood flow in CTP performed at low radiation dose. We first build a dictionary from high-dose perfusion maps using online dictionary learning and then perform deconvolution-based hemodynamic parameters estimation on the low-dose CTP data. Our method is validated on clinical data of patients with normal and pathological CBF maps. The results show that we achieve superior performance than existing methods, and potentially improve the differentiation between normal and ischemic tissue in the brain. PMID:23542422

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

    PubMed Central

    Fang, Ruogu; Chen, Tsuhan; Sanelli, Pina C.

    2014-01-01

    Computed tomography perfusion (CTP) is an important functional imaging modality in the evaluation of cerebrovascular diseases, particularly in acute stroke and vasospasm. However, the post-processed parametric maps of blood flow tend to be noisy, especially in low-dose CTP, due to the noisy contrast enhancement profile and the oscillatory nature of the results generated by the current computational methods. In this paper, we propose a robust sparse perfusion deconvolution method (SPD) to estimate cerebral blood flow in CTP performed at low radiation dose. We first build a dictionary from high-dose perfusion maps using online dictionary learning and then perform deconvolution-based hemodynamic parameters estimation on the low-dose CTP data. Our method is validated on clinical data of patients with normal and pathological CBF maps. The results show that we achieve superior performance than existing methods, and potentially improve the differentiation between normal and ischemic tissue in the brain. PMID:23542422

  19. A Phantom Tissue System for the Calibration of Perfusion Measurements

    PubMed Central

    Mudaliar, Ashvinikumar V.; Ellis, Brent E.; Ricketts, Patricia L.; Lanz, Otto I.; Scott, Elaine P.; Diller, Thomas E.

    2008-01-01

    A convenient method for testing and calibrating surface perfusion sensors has been developed. A phantom tissue model is used to simulate the nondirectional blood flow of tissue perfusion. A computational fluid dynamics (CFD) model was constructed in Fluent® to design the phantom tissue and validate the experimental results. The phantom perfusion system was used with a perfusion sensor based on clearance of thermal energy. A heat flux gage measures the heat flux response of tissue when a thermal event (convective cooling) is applied. The blood perfusion and contact resistance are estimated by a parameter estimation code. From the experimental and analytical results, it was concluded that the probe displayed good measurement repeatability and sensitivity. The experimental perfusion measurements in the tissue were in good agreement with those of the CFD models and demonstrated the value of the phantom tissue system. PMID:19045509

  20. Hydrostatic Hyperbaric Chamber Ventilation System

    NASA Technical Reports Server (NTRS)

    Sargusingh, Miriam M.

    2011-01-01

    The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications, including the treatment of medical conditions. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy available in the developing world for the treatment of a variety of medical conditions. Specifically, hyperbaric oxygen therapy is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. Hyperbaric oxygen therapy is simply too expensive and too dangerous to implement in the developing world using standard equipment. The hydrostatic hyperbaric chamber technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system that will provide controlled pressurization of the system, and provide adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware, supports sustainability.