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. Perfusion and ventilation of isolated canine lungs

    PubMed Central

    Otto, T. J.; Trenkner, M.; Stopczyk, A.; Gawdzi?ski, M.; Che?stowska, B.

    1968-01-01

    In order to evaluate methods of preserving lungs for use in transplantation, experiments on 28 mongrel dogs were carried out. Two methods were tried—first, mechanical respiration of isolated lungs under deep hypothermia, with the vascular bed filled with blood; and, secondly, the perfusion of isolated lungs with the aid of a modified DeWall's apparatus. Allogenic transplantations of lungs preserved in both ways were carried out. Gasometric and histological examinations of preserved lungs, before and after transplantation, were performed. The best results were obtained with perfusion under hypothermic conditions; ventilation without perfusion resulted in failure. Lung transplantation was successful when, after being preserved, the lung remained unchanged. Major discrepancies between the macroscopic and microscopic findings in preserved lungs were observed. An original classification of the changes occurring in preserved lungs is proposed. PMID:4886091

  3. Pulmonary ventilation and perfusion studies in lung cancer

    SciTech Connect

    Narabayashi, I.; Otsuka, N.

    1984-02-01

    In 46 patients with bronchogenic carcinoma, the diagnostic significance of pulmonary ventilation images by the continuous inhalation of Kr-81m gas, which has an extremely short half life, was studied in comparison with pulmonary perfusion images with Tc-99m MAA. The data were processed using digital analysis techniques. There were 15 cases with discrepancies between ventilation and perfusion. The V/Q ratios of the affected lung among the 43 patients showed values above 1.2 in nine cases and below 0.8 in six cases. The Kr-81m ventilation and Tc-99m perfusion images were compared before and after radiation therapy in eight patients. It was possible to assess the therapeutic effect on regional ventilation and regional perfusion, which could not be evaluated by chest x-ray alone, under the same conditions of normal breathing.

  4. Quantification of Regional Ventilation-Perfusion Ratios with PET

    Microsoft Academic Search

    Marcos F. Vidal Melo; Dominick Layfield; R. Scott Harris; Kevin O'Neill; Guido Musch; Torsten Richter; Tilo Winkler; Alan J. Fischman; Jose G. Venegas

    2003-01-01

    The topographic matching of alveolar ventilation (VA) and per- fusion (Q ? ) is the main determinant of gas exchange efficiency of the lung. However, no pulmonary functional imaging technique has been shown to predict whole-lung gas exchange in health and disease. This study aims to present a PET-based method to estimate regional alveolar ventilation-to-perfusion ratios (VA\\/Q ? ) predictive

  5. 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

  6. 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

  7. The incidence and etiology of the ventilation/perfusion reverse mismatch defect

    SciTech Connect

    Carvalho, P.; Lavender, J.P. (Hammersmith Hospital, London (England))

    1989-08-01

    Kr-81m ventilation and Tc-99m perfusion images of 392 patients were examined retrospectively for the incidence and etiology of the reverse mismatch defect, which is characterized by a region of lung where the perfusion defect exceeds the ventilation defect. Forty-six patients (11.7%) showed such defects. The most frequent causes were pneumonia (15%), atelactasis (15%), pleural effusions (15%), chronic obstructive airway disease (24%), and bronchial obstruction (31%). The significance of the reverse mismatch defect is discussed.

  8. 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.

  9. Standing prone positioning in establishing causality between matched ventilation-perfusion defects and pleural effusion.

    PubMed

    Fotos, Joseph S; Tulchinsky, Mark

    2015-01-01

    Ventilation-perfusion scintigraphy is routinely performed in patients with suspected pulmonary thromboembolism. Pleural effusions in such patients are common and can cause matched ventilation-perfusion defects. This is especially true of the posterior projections in the supine patient. Prone positioning has been described as a useful technique to redistribute pleural fluid anteriorly, exposing perfusion in posterior lung fields; however, some patients have a concurrent condition that renders prone positioning difficult. This report discusses a modified technique that allows patients to be imaged in a standing prone position with excellent results. PMID:25247271

  10. Ventilation-perfusion scans in neonatal regional pulmonary emphysema complicating ventilatory assistance.

    PubMed

    Leonidas, J C; Moylan, F M; Kahn, P C; Ramenofsky, M L

    1978-08-01

    Two cases of ventilator-related neonatal lobar overexpansion with similar radiographic appearance, but probably different pathogenesis, are presented. In one infant, persistent interstitial lobar emphysema was confirmed by markedly decreased perfusion shown on scintigraphy; this information was of great value in predicting the beneficial effect of lobectomy. In the other case, ventilation and perfusion scans indicated functional value of the emphysematous lobe and correctly suggested conservative management. Radioisotope lung scans may provide valuable information regarding lung function in regional pulmonary emphysema associated with assisted ventilation in neonatal respiratory distress syndrome, and thus determine patient management. PMID:98002

  11. Static and dynamic lung volumes and ventilation-perfusion abnormality in adult asthma

    PubMed Central

    Mayfield, J. D.; Paez, P. N.; Nicholson, D. P.

    1971-01-01

    Dynamic lung volumes (forced vital capacity, forced expiratory volume in 0·5 second and in 1·0 second), static lung volumes (total lung capacity, functional residual capacity, residual volume), and ventilation-perfusion relationships (alveolar-arterial oxygen tension difference, alveolar dead space ventilation to tidal volume ratio, arterial oxygen and carbon dioxide tension, and the fractional ventilation and perfusion relationship by the three-compartment lung model) were measured in adult asthmatics during the acute, recovery, and stable or asymptomatic phases of an asthmatic attack. Eighteen patients were studied during 20 separate asthmatic attacks. The patients behaved in one of three ways with regard to total lung capacity (TLC): group I had an elevated TLC during the acute asthmatic attack which returned to normal, group II had a normal TLC throughout the attack, and group III had an elevated TLC that did not return to normal on recovery from the asthmatic attack. With the patients separated into the three groups, the other pulmonary function measurements, especially the measurements of ventilation-perfusion abnormality, were compared. There were no statistically significant differences of ventilation-perfusion abnormality between groups I, II, or III. There was a tendency for perfusion abnormality to be less during the acute phase of the asthmatic attack in patients with an elevated TLC (group I). The three-compartment lung model revealed the major abnormality in all groups to be an increased fraction of unventilated but perfused lung. PMID:5134060

  12. 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

  13. 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

  14. 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.

  15. Interaction of formaldehyde with glutathione in the isolated/ventilated perfused lung and the isolated perfused liver

    SciTech Connect

    Ayres, P.H.; Marshall, T.C.; Sun, J.D.; Bond, J.A.; Hobbs, C.H.

    1985-01-01

    The interaction of formaldehyde (CH/sub 2/O) with reduced glutathione (GSH) was evaluated in aqueous solution and in isolated perfused lungs and livers. Addition of CH/sub 2/O (0-4.9 mM) to a solution of 0.17 mM GSH in 2 mM EDTA, pH 7.4, resulted in a time- and concentration-dependent depletion of GSH. Perfusion of livers with fortified Krebs-Ringer bicarbonate buffer containing 0.3-4.9 mM CH/sub 2/O resulted in a dose-dependent depletion of GSH. Perfusion of isolated ventilated lungs with perfusate containing 4.9 mM CH/sub 2/O resulted in a depletion of GSH to 75% of controls. However, lower concentrations of CH/sub 2/O in the lung perfusate did not result in depletion of GSH. These results demonstrate that exposure ito CH/sub 2/O in aqueous solution or in the perfused lung and liver is capable of depleting endogenous GSH. However, the concentrations of CH/sub 2/O required to yield a significant depletion of endogenous GSH exceed those encountered in vivo. Thus it is unlikely that depletion of GSH by CH/sub 2/O is a causal factor in formaldehyde-induced toxicity.

  16. Prediction of postoperative pulmonary function following thoracic operations. Value of ventilation-perfusion scanning

    SciTech Connect

    Bria, W.F.; Kanarek, D.J.; Kazemi, H.

    1983-08-01

    Surgical resection of lung cancer is frequently required in patients with severely impaired lung function resulting from chronic obstructive pulmonary disease. Twenty patients with obstructive lung disease and cancer (mean preoperative forced expiratory volume in 1 second (FEV1) . 1.73 L) were studied preoperatively and postoperatively by spirometry and radionuclide perfusion, single-breath ventilation, and washout techniques to test the ability of these methods to predict preoperatively the partial loss of lung function by the resection. Postoperative FEV1 and forced vital capacity (FVC) were accurately predicted by the formula: postoperative FEV1 (or FVC) . preoperative FEV1 X percent function of regions of lung not to be resected (r . 0.88 and 0.95, respectively). Ventilation and perfusion scans are equally effective in prediction. Washout data add to the sophistication of the method by permitting the qualitative evaluation of ventilation during tidal breathing. Criteria for patients requiring the study are suggested.

  17. Evaluation of pulmonary perfusion in lung regions showing isolated xenon-133 ventilation washout defects

    SciTech Connect

    Bushnell, D.L.; Sood, K.B.; Shirazi, P.; Pal, I. (VA Hines Hospital, IL (USA))

    1990-08-01

    Xenon-133 washout phase imaging is often used to help determine whether the etiology of a perfusion defect is embolic or due to pulmonary parenchymal pathology, such as chronic obstructive pulmonary disease. This study was designed to evaluate the pulmonary blood flow patterns associated with isolated defects on xenon washout images. Scintigraphic lung studies were reviewed until 100 cases with abnormal ventilation results were obtained. Ventilation abnormalities were compared with the corresponding perfusion scan results at the same anatomic site. Of the 208 individual lung regions with xenon abnormalities, 111 showed isolated washout defects (that is, with normal washin). Ninety-four of these 111 sites showed either normal perfusion or a small, nonsegmental corresponding perfusion defect. Three segmental perfusion defects were noted in association with isolated xenon retention. In each of these cases, however, the patient was felt actually to have pulmonary embolism. Thus, it is recommended that, for interpretation of scintigraphic images in the assessment of pulmonary embolism, lung pathology associated with isolated xenon retention not be considered a potential cause for large or segmental perfusion defects.

  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. Assessment of the intrapulmonary ventilation-perfusion distribution after the Fontan procedure for complex cardiac anomalies: Relation to pulmonary hemodynamics

    SciTech Connect

    Matsushita, T.; Matsuda, H.; Ogawa, M.; Ohno, K.; Sano, T.; Nakano, S.; Shimazaki, Y.; Nakahara, K.; Arisawa, J.; Kozuka, T. (Osaka Univ. Medical School (Japan))

    1990-03-15

    In 12 patients who underwent the Fontan procedure for complex cardiac anomalies, lung scanning with xenon-133 was performed to assess the intrapulmonary ventilation-perfusion distribution, and comparison was made with a control group. All data were then analyzed in relation to either pre- or postoperative pulmonary hemodynamic data. In ventilation scans, the intrapulmonary distribution in the right lung was almost normal. In perfusion scans, an abnormal increased upper to lower lobe perfusion ratio greater than the normal value found in the control group was noted in seven patients (58.3%). There was a significant correlation (p less than 0.02) between the upper to lower lobe perfusion ratio and postoperative pulmonary vascular resistance. Furthermore, this perfusion ratio correlated inversely with the preoperative (p less than 0.005) and postoperative (p less than 0.02) right pulmonary artery area index, defined as the ratio of cross-sectional area to the normal value. Of five patients with less than 90% arterial oxygen saturation, four showed an abnormal distribution of pulmonary blood flow greater than the normal perfusion ratio. No patient had evidence of a pulmonary arteriovenous fistula by the echocardiographic contrast study. These results suggest that abnormal distribution of pulmonary blood flow to the upper lung segment may develop in patients after the Fontan procedure, and that insufficient size of the pulmonary artery before operation and the consequent postoperative elevation of pulmonary vascular resistance may be responsible for this perfusion abnormality.

  20. Effects of carbonic anhydrase inhibition on ventilation-perfusion matching in the dog lung.

    PubMed Central

    Swenson, E R; Robertson, H T; Hlastala, M P

    1993-01-01

    Lung carbonic anhydrase (CA) permits rapid pH responses when changes in regional ventilation or perfusion alter airway and alveolar PCO2. These pH changes affect airway and vascular resistances and lung compliance to optimize the balance of regional ventilation (VA) and perfusion (Q) in the lung. To test the hypothesis that these or other CA-dependent mechanisms contribute to VA/Q matching, we administered acetazolamide (25 mg/kg intravenously) to six anesthetized and paralyzed dogs and measured VA/Q relationships before and after CA inhibition by the multiple inert gas elimination technique. Four other groups of dogs were studied to control for possible confounding effects of time under anesthesia and nonselective CA inhibition by acetazolamide: (a) saline placebo as a control for duration of anesthesia, (b) 4% CO2 inhalation to mimic systemic CO2 retention, (c) 1 mg/kg benzolamide (a selective renal CA inhibitor) or 0.5 meq/kg HCl to mimic systemic metabolic acidosis, and (d) 500 mg/kg 4,4'-dinitrostilbene-2,2'-disulfonate (an inhibitor of red cell band 3 protein) to mimic the respiratory acidosis arising from an intracapillary block to rapid mobilization of plasma HCO3- in CO2 exchange. Acetazolamide increased VA/Q mismatch and reduced arterial PO2 measured at equilibrium but these did not occur in the control group. There was no deterioration in VA/Q matching when systemic respiratory acidosis produced either by CO2 inhalation or 4,4'-dinitrostilbene-2,2'-disulfonate or metabolic acidosis (benzolamide or HCl) were imposed to mimic the effects of acetazolamide apart from its inhibition of lung CA. These results support the concept that lung CA subserves VA/Q matching in the normal lung. Images PMID:8349809

  1. Real-time 3D electrical impedance imaging for ventilation and perfusion of the lung in lateral decubitus position.

    PubMed

    Kao, Tzu-Jen; Amm, Bruce; Xin Wang; Boverman, Gregory; Shoudy, David; Sabatini, James; Ashe, Jeffrey; Newell, Jonathan; Saulnier, Gary; Isaacson, David; Davenport, David

    2014-08-01

    We report a prototype Electrical Impedance Imaging System. It is able to detect the gravity-induced changes in the distributions of perfusion and ventilation in the lung between supine and lateral decubitus positions. Impedance data were collected on healthy volunteer subjects and 3D reconstructed images were produced in real-time, 20 frames per second on site, without using averaging or a contrast agent. Imaging data also can be reconstructed offline for further analysis. PMID:25570163

  2. 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.

  3. Planar ventilation-perfusion imaging for pulmonary embolism: the case for "outcomes" medicine.

    PubMed

    Freeman, Leonard M; Glaser, Joseph E; Haramati, Linda B

    2012-01-01

    Single-photon emission computed tomography (SPECT) has been a significant advancement in scintigraphy, impacting many areas of diagnosis. It has begun to find use in ventilation-perfusion (V/Q) scintigraphy. However, its utility has been limited in the United States because of a lack of an optimal and Food and Drug Administration-approved SPECT ventilatory agent. Although SPECT V/Q can show more and smaller mismatches than planar studies, there is persistent debate regarding the clinical significance of these smaller pulmonary emboli (PE); they may be neither clinically significant nor require treatment. Available data suggest that planar V/Q, SPECT V/Q, and computed tomographic pulmonary angiography (CTPA) have similar false-negative rates and thus have a similar impact on outcomes. In most cases, emergency department physicians are the first to encounter patients who may have PE, and they frequently use an imaging study as part of the evaluation. We discuss the rational for triaging patients to different imaging modalities with the use of chest radiography and the strengths and weaknesses of each modality. Detailed anatomy is an advantage of CTPA, breast radiation dose is reduced with scintigraphy, and imaging is quicker and more detailed with SPECT. We also review planar and SPECT V/Q and CTPA from the differing vantage points of diagnostic accuracy vs patient outcomes. Whatever modality their patients require, physicians can be confident that they are all similarly efficacious at diagnosing clinically relevant emboli. PMID:22117808

  4. 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

  5. The gravitational distribution of ventilation-perfusion ratio is more uniform in prone than supine posture in the normal human lung

    PubMed Central

    Sá, Rui Carlos; Theilmann, Rebecca J.; Buxton, Richard B.; Prisk, G. Kim; Hopkins, Susan R.

    2013-01-01

    The gravitational gradient of intrapleural pressure is suggested to be less in prone posture than supine. Thus the gravitational distribution of ventilation is expected to be more uniform prone, potentially affecting regional ventilation-perfusion (V?a/Q?) ratio. Using a novel functional lung magnetic resonance imaging technique to measure regional V?a/Q? ratio, the gravitational gradients in proton density, ventilation, perfusion, and V?a/Q? ratio were measured in prone and supine posture. Data were acquired in seven healthy subjects in a single sagittal slice of the right lung at functional residual capacity. Regional specific ventilation images quantified using specific ventilation imaging and proton density images obtained using a fast gradient-echo sequence were registered and smoothed to calculate regional alveolar ventilation. Perfusion was measured using arterial spin labeling. Ventilation (ml·min?1·ml?1) images were combined on a voxel-by-voxel basis with smoothed perfusion (ml·min?1·ml?1) images to obtain regional V?a/Q? ratio. Data were averaged for voxels within 1-cm gravitational planes, starting from the most gravitationally dependent lung. The slope of the relationship between alveolar ventilation and vertical height was less prone than supine (?0.17 ± 0.10 ml·min?1·ml?1·cm?1 supine, ?0.040 ± 0.03 prone ml·min?1·ml?1·cm?1, P = 0.02) as was the slope of the perfusion-height relationship (?0.14 ± 0.05 ml·min?1·ml?1·cm?1 supine, ?0.08 ± 0.09 prone ml·min?1·ml?1·cm?1, P = 0.02). There was a significant gravitational gradient in V?a/Q? ratio in both postures (P < 0.05) that was less in prone (0.09 ± 0.08 cm?1 supine, 0.04 ± 0.03 cm?1 prone, P = 0.04). The gravitational gradients in ventilation, perfusion, and regional V?a/Q? ratio were greater supine than prone, suggesting an interplay between thoracic cavity configuration, airway and vascular tree anatomy, and the effects of gravity on V?a/Q? matching. PMID:23620488

  6. 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

  7. Laser-polarized (3)He as a probe for dynamic regional measurements of lung perfusion and ventilation using magnetic resonance imaging.

    PubMed

    Viallon, M; Berthezène, Y; Décorps, M; Wiart, M; Callot, V; Bourgeois, M; Humblot, H; Briguet, A; Crémillieux, Y

    2000-07-01

    Magnetic resonance imaging (MRI) using laser-polarized noble gases, such as (129)Xe and (3)He, allows unparalleled noninvasive information on gas distribution in lung airways and distal spaces. In addition to pulmonary ventilation, lung perfusion assessment is crucial for proper diagnosis of pathological conditions, such as pulmonary embolism. Magnetic resonance perfusion imaging usually can be performed using techniques based on the detection of water protons in tissues. However, lung proton imaging is extremely difficult due to the low proton density and the magnetically inhomogeneous structure of the lung parenchyma. Here we show that laser-polarized (3)He can be used as a noninvasive probe to image, in a single MRI experiment, not only the ventilation but also the perfusion state of the lungs. Blood volume maps of the lungs were generated based on the (3)He signal depletion during the first pass of a superparamagnetic contrast agent bolus. The combined and simultaneous lung ventilation and perfusion assessments are demonstrated in normal rat lungs and are applied to an experimental animal model of pulmonary embolism. Magn Reson Med 44:1-4, 2000. PMID:10893513

  8. Ventilation

    Microsoft Academic Search

    W. Wilkinson

    1885-01-01

    A VERY common source of trouble with respect to ventilation is the absence of any arrangement for the supply of air to fires. So long as a fire draws on the general atmosphere of the room it is supposed to warm for its supply of oxygen, there must be the ``draughts'' so often complained of, and people are warm on

  9. Imaging of the three-dimensional alveolar structure and the alveolar mechanics of a ventilated and perfused isolated rabbit lung with Fourier domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Popp, Alexander; Wendel, Martina; Knels, Lilla; Koch, T.; Koch, Edmund

    2006-01-01

    In this feasibility study, Fourier domain optical coherence tomography (FDOCT) is used for visualizing the 3-D structure of fixated lung parenchyma and to capture real-time cross sectional images of the subpleural alveolar mechanics in a ventilated and perfused isolated rabbit lung. The compact and modular setup of the FDOCT system allows us to image the first 500 µm of subpleural lung parenchyma with a 3-D resolution of 16×16×8 µm (in air). During mechanical ventilation, real-time cross sectional FDOCT images visualize the inflation and deflation of alveoli and alveolar sacks (acini) in successive images of end-inspiratory and end-expiratory phase. The FDOCT imaging shows the relation of local alveolar mechanics to the setting of tidal volume (VT), peak airway pressure, and positive end-expiratory pressure (PEEP). Application of PEEP leads to persistent recruitment of alveoli and acini in the end-expiratory phase, compared to ventilation without PEEP where alveolar collapse and reinflation are observed. The imaging of alveolar mechanics by FDOCT will help to determine the amount of mechanical stress put on the alveolar walls during tidal ventilation, which is a key factor in understanding the development of ventilator induced lung injury (VILI).

  10. Liver Trapping of 99mTc Macroaggregated Albumin During Ventilation/Perfusion Scintigraphy in a Patient With Superior Vena Cava Stenosis as Demonstrated by SPECT/CT.

    PubMed

    Rousseau, Etienne; Leclerc, Yves; Prévost, Sylvain; Keu, Khun Visith

    2015-07-01

    A 50-year-old woman presented to our institution with a 1-day history of right posterior thoracic pain and dyspnea. She had a previous history of conservative resection of a high-grade basal-like infiltrating ductal carcinoma of the right breast 2 years before, subsequently treated by chemotherapy and radiotherapy. A ventilation and perfusion (VQ) scintigraphy performed for suspected pulmonary embolism showed an abnormal deposition of Tc macroaggregated albumin (Tc-MAA) in the left lobe of the liver. This unusual finding prompted additional imaging that demonstrated a superior vena cava stenosis. PMID:26018706

  11. Metabolism and macromolecular covalent binding of (/sup 14/C)-1-nitropyrene in isolated perfused and ventilated rat lungs

    SciTech Connect

    Bond, J.A.; Mauderly, J.L.

    1984-09-01

    The purpose of this study was to quantitate l-nitropyrene (1-NP) metabolism and macromolecular covalent binding in the isolated perfused rat lung. Rat lungs were perfused with 2, 5, or 24 microM (/sup 14/C)-1-NP for 90 min. Tidal volume and dynamic lung compliance were monitored throughout the perfusion to document the ventilatory pattern and the decay of tissue elasticity. Perfusate was sampled periodically throughout the experiment and analyzed for 1-NP metabolites with high-performance liquid chromatography. In all experiments, both dynamic lung compliance and tidal volume declined in a nearly linear manner and were approximately 60% of the initial value at the end of 90 min of perfusion. At all concentrations of (/sup 14/C)-1-NP tested, less than 5 to 6% of the total amount of (/sup 14/C)-1-NP added was metabolized in lungs from control and phenobarbital (PB)-treated rats. Lungs from control and PB- and 3-methylcholanthrene (3-MC)-treated rats metabolized (/sup 14/C)-1-NP to oxidized, reduced, and conjugated metabolites. The major metabolites were 3-, 6-, and 8-hydroxynitropyrene. Treatment of rats with PB resulted in a 60% increase in the total metabolism of (/sup 14/C)-1-NP, whereas treatment of rats with 3-MC resulted in a 10-fold increase in the rate of metabolism of (/sup 14/C)-1-NP when compared to controls. Conjugate hydrolysis studies indicated that the water-soluble metabolites from lungs of control and PB- and 3-MC-treated rats consisted of hydroxynitropyrene glucuronides and hydroxynitropyrene sulfate conjugates. Quantities of /sup 14/C covalently bound to lung macromolecules after 90 min of perfusion from lungs of control and PB-treated rats were 0.06 to 0.21 nmol equivalents/g lung. However, in lungs from 3-MC-treated rats, there was a 20-fold increase in quantities of 14C covalently bound when compared to lungs from either control or PB-treated rats.

  12. 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.

  13. 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

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

    SciTech Connect

    Keenan, A.M.; Palevsky, H.I.; Steinberg, M.E.; Hartman, K.M.; Alavi, A.; Lotke, P.A. (Univ. of Pennsylvania, Philadelphia (USA))

    1991-01-01

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

  15. 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

  16. Anaesthesia ventilators

    PubMed Central

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-01-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits. PMID:24249886

  17. Generation of parametric images during routine Tc-99m PYP inhalation/Tc-99m MAA perfusion lung scintigraphy. Technical note.

    PubMed

    Miron, S D; Wiesen, E J; Feiglin, D H; Cohen, A M; Bellon, E M

    1991-07-01

    A simple technique is described for generating ventilation/perfusion ratio and perfusion/ventilation ratio images from the posterior Tc-99m PYP aerosol inhalation and Tc-99m MAA perfusion images obtained during routine lung scintigraphy. These images highlight areas of ventilation/perfusion incongruence--mismatch or reverse mismatch--that may sometimes be difficult to detect on conventional images. PMID:1834387

  18. 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 ...

  19. [Noninvasive ventilation].

    PubMed

    Heindl, W

    1999-10-15

    Non invasive ventilation is defined as mechanical ventilation without the use of endotracheal intubation and has been increasingly established within intensive care units during the last decades. Negative pressure ventilation and non invasive positive pressure ventilation have been successfully applied, first in chronic respiratory failure (CRF) due to various causes and later in acute respiratory failure (ARF). In this review ventilation modes, indications, contraindications and side effects of non invasive ventilation are analysed and the impact of non invasive ventilation on the physiology, pathophysiology and outcome of CRF and ARF, and possible applications in CRF (restrictive chest and pulmonary diseases, neuromuscular diseases and COPD) and ARF are discussed. It is concluded that non invasive ventilation should be included in the routine management of respiratory failure at all intensive care units. PMID:10568010

  20. Metabolism of 5Hydroxytryptophan in the Isolated Perfused Rat Lung

    Microsoft Academic Search

    Ruben R. Ben-Harari; A. Parent Ermini; J. Kleinerman

    1990-01-01

    The metabolism of 5-hydroxytryptophan (5-HTP) and tryptophan (TRP) in a single pass across the pulmonary circulation was studied in the isolated ventilated perfused rat lung and by high pressure liquid chromatography. The metabolism of 5-HTP was dependent on the rate of lung perfusion and the duration of infusion of 5-HTP, and was a saturable process with an apparent Km of

  1. 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

  2. Home ventilation.

    PubMed

    Simonds, A K

    2003-11-01

    Home ventilation is a growth area. Rapid expansion during the 1990s was stimulated by the development of noninvasive ventilation (NIV) via a mask and the recognition that an increased number of patient groups can benefit. Although patients receiving NIV in the home outnumber those receiving invasive ventilation via tracheostomy, there is substantial variation in practice between European countries. Evidence that individuals who develop ventilatory failure as a consequence of chest wall disease or stable neuromuscular disease such as old poliomyelitis benefit from nocturnal NIV is overwhelming. Patients with progressive neuromuscular disease such as Duchenne muscular dystrophy and amyotrophic lateral sclerosis can also derive prolongation of life, palliation of symptoms and an improvement in quality of life. Home ventilation in chronic obstructive pulmonary disease (COPD) patients remains controversial. Multicentric randomised controlled trials of long-term oxygen therapy (LTOT) versus NIV plus LTOT in COPD have produced mixed results, although certain subgroups, e.g. those with recurrent infective exacerbations requiring short-term NIV, patients aged >65 yrs, and those with uncontrolled hypercapnia on LTOT or symptomatic nocturnal hypoventilation, may benefit. At the other end of the age spectrum, children as young as a few months can be successfully treated with noninvasive ventilation. Most work on paediatric home ventilation centres on children with congenital neuromuscular disease. Pressure preset bilevel ventilators are now the dominant form of ventilator in adults and children. Discharge planning is vital for the home ventilator patient and a sensible risk management strategy should be in place. PMID:14621116

  3. Ventilation Model

    SciTech Connect

    H. Yang

    1999-11-04

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

  4. 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).

  5. Liquid ventilation.

    PubMed

    Sarkar, Suman; Paswan, Anil; Prakas, S

    2014-01-01

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

  6. Ventilation systems

    NASA Astrophysics Data System (ADS)

    Olander, L.

    Two different types of ventilation systems and their components are addressed: general ventilation and local or process ventilation. Calculation of the flow rates used in the different systems is addressed. The many different types of flow calculations, how they are used, and some of the computer programs that could be used for these calculations are described. Some calculations start with assumptions regarding air flow rates in rooms and locals. The flow rates can be chosen from rule of thumb or regulations or standards. Thereafter the designer calculates necessary heat and cooling loads, pressure drops, fan effect, etc. The other type of calculation is not very common. By using demands on concentrations, temperatures or air velocities the flow rates are calculated. These calculations include contaminant source generation rates, use of models (physical and theoretical), and computational fluid dynamics. The latter are focused upon.

  7. Nasal ventilation.

    PubMed Central

    Simonds, A. K.

    1998-01-01

    Nasal intermittent positive pressure ventilation is likely to have an increasing role in the management of acute ventilatory failure, weaning, and chronic ventilatory problems. Further improvements in ventilator and mask design will be seen. Appropriate application is likely to reduce both mortality and admissions to intensive care, while domiciliary use can improve life expectancy and/or quality of life in chronic ventilatory disorders. As with any new technique, enthusiasm should not outweigh clear outcome information, and possible new indications should always be subject to careful assessment. Images Figure 2 PMID:9799887

  8. Ventilator-driven xenon ventilation studies

    SciTech Connect

    Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

    1984-07-01

    A modification of a common commerical Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilator rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration.

  9. Dead space: the physiology of wasted ventilation.

    PubMed

    Robertson, H Thomas

    2015-06-01

    An elevated physiological dead space, calculated from measurements of arterial CO2 and mixed expired CO2, has proven to be a useful clinical marker of prognosis both for patients with acute respiratory distress syndrome and for patients with severe heart failure. Although a frequently cited explanation for an elevated dead space measurement has been the development of alveolar regions receiving no perfusion, evidence for this mechanism is lacking in both of these disease settings. For the range of physiological abnormalities associated with an increased physiological dead space measurement, increased alveolar ventilation/perfusion ratio (V'A/Q') heterogeneity has been the most important pathophysiological mechanism. Depending on the disease condition, additional mechanisms that can contribute to an elevated physiological dead space measurement include shunt, a substantial increase in overall V'A/Q' ratio, diffusion impairment, and ventilation delivered to unperfused alveolar spaces. PMID:25395032

  10. 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...

  11. 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

  12. Regional pulmonary perfusion following human heart-lung transplantation

    SciTech Connect

    Lisbona, R.; Hakim, T.S.; Dean, G.W.; Langleben, D.; Guerraty, A.; Levy, R.D. (Royal Victoria Hospital, Montreal, Quebec (Canada))

    1989-08-01

    Ventilation and perfusion scans were obtained in six subjects who had undergone heart-lung transplantation with consequent denervation of the cardiopulmonary axis. Two of the subjects had developed obliterative bronchiolitis, which is believed to be a form of chronic rejection. Their pulmonary function tests demonstrated airflow obstruction and their scintigraphic studies were abnormal. In the remaining four subjects without obstructive airways disease, ventilation and planar perfusion scans were normal. Single photon emission computed tomography imaging of pulmonary perfusion in these patients revealed a layered distribution of blood flow indistinguishable from that of normal individuals. It is concluded that neurogenic mechanisms have little influence on the pattern of local pulmonary blood flow at rest.

  13. 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.

  14. Ventilator-driven xenon ventilation studies

    SciTech Connect

    Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

    1984-07-01

    A modification of a common commercial Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilatory rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration.

  15. Pulmonary inactivation of 5-hydroxytryptamine is decreased during cigarette smoke ventilation of rat isolated lungs.

    PubMed Central

    Karhi, T.; Rantala, A.; Toivonen, H.

    1982-01-01

    1 The effect of cigarette smoke ventilation on the inactivation of [14C]-5-hydroxytryptamine (5-HT) was studied in isolated perfused lungs of the rat. 2 [14C]-5-HT 9.6 nmol was infused into the pulmonary circulation of rat lungs in 3 min. The nonrecirculating perfusion effluent was collected during the 5-HT infusion in three consecutive 1 min fractions. The amount of metabolites of 5-HT was determined from the perfusion effluent and from the perfused lungs. 3 The amount of metabolites of 5-HT in the perfused lungs was also decreased by cigarette smoke ventilation, although the total amount of radioactivity in the lung tissue was not significantly changed. 5 The decreased pulmonary inactivation of 5-HT may cause increased circulating levels of 5-HT, which would explain some cardiovascular changes during smoking. PMID:7139186

  16. Earth's Energy Imbalance and Implications

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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. We update our analysis of Earth's observed energy imbalance through 2011 and compare this with climate simulations. Observed global surface temperature change and ocean heat gain together constrain the net climate forcing, implying existence of a large negative forcing by human-made aerosols. Continued failure to quantify the specific origins of this large forcing is untenable, as knowledge of changing aerosol effects is needed to understand future climate change. We discuss implications of the trend of observed sea level rise in recent years, and its consistency with reported ice melt rates and ocean thermal expansion.

  17. Identifying acid-base and electrolyte imbalances.

    PubMed

    Gooch, Michael D

    2015-08-15

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

  18. Earth's Energy Imbalance and Ocean Heat Storage

    Microsoft Academic Search

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

    2006-01-01

    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

  19. Metformin attenuates ventilator-induced lung injury

    PubMed Central

    2012-01-01

    Introduction Diabetic patients may develop acute lung injury less often than non-diabetics; a fact that could be partially ascribed to the usage of antidiabetic drugs, including metformin. Metformin exhibits pleiotropic properties which make it potentially beneficial against lung injury. We hypothesized that pretreatment with metformin preserves alveolar capillary permeability and, thus, prevents ventilator-induced lung injury. Methods Twenty-four rabbits were randomly assigned to pretreatment with metformin (250 mg/Kg body weight/day per os) or no medication for two days. Explanted lungs were perfused at constant flow rate (300 mL/min) and ventilated with injurious (peak airway pressure 23 cmH2O, tidal volume ?17 mL/Kg) or protective (peak airway pressure 11 cmH2O, tidal volume ?7 mL/Kg) settings for 1 hour. Alveolar capillary permeability was assessed by ultrafiltration coefficient, total protein concentration in bronchoalveolar lavage fluid (BALF) and angiotensin-converting enzyme (ACE) activity in BALF. Results High-pressure ventilation of the ex-vivo lung preparation resulted in increased microvascular permeability, edema formation and microhemorrhage compared to protective ventilation. Compared to no medication, pretreatment with metformin was associated with a 2.9-fold reduction in ultrafiltration coefficient, a 2.5-fold reduction in pulmonary edema formation, lower protein concentration in BALF, lower ACE activity in BALF, and fewer histological lesions upon challenge of the lung preparation with injurious ventilation. In contrast, no differences regarding pulmonary artery pressure and BALF total cell number were noted. Administration of metformin did not impact on outcomes of lungs subjected to protective ventilation. Conclusions Pretreatment with metformin preserves alveolar capillary permeability and, thus, decreases the severity of ventilator-induced lung injury in this model. PMID:22827994

  20. Earth's energy imbalance and implications

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

    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 surface temperature change and ocean heat gain together constrain the net climate forcing and ocean mixing rates. We conclude that most climate models mix heat too efficiently into the deep ocean and as a result underestimate the negative forcing by human-made aerosols. Aerosol climate forcing today is inferred to be -1.6 ± 0.3 W m-2, implying substantial aerosol indirect climate forcing via cloud changes. Continued failure to quantify the specific origins of this large forcing is untenable, as knowledge of changing aerosol effects is needed to understand future climate change. We conclude that recent slowdown of ocean heat uptake was caused by a delayed rebound effect from Mount Pinatubo aerosols and a deep prolonged solar minimum. Observed sea level rise during the Argo float era is readily accounted for by ice melt and ocean thermal expansion, but the ascendency of ice melt leads us to anticipate acceleration of the rate of sea level rise this decade. Humanity is potentially vulnerable to global temperature change, as discussed in the Intergovernmental Panel on Climate Change (IPCC, 2001, 2007) reports and by innumerable authors. Although climate change is driven by many climate forcing agents and the climate system also exhibits unforced (chaotic) variability, it is now widely agreed that the strong global warming trend of recent decades is caused predominantly by human-made changes of atmospheric composition (IPCC, 2007). The basic physics underlying this global warming, the greenhouse effect, is simple. An increase of gases such as CO2 makes the atmosphere more opaque at infrared wavelengths. This added opacity causes the planet's heat radiation to space to arise from higher, colder levels in the atmosphere, thus reducing emission of heat energy to space. The temporary imbalance between the energy absorbed from the sun and heat emission to space, causes the planet to warm until planetary energy balance is restored. The planetary energy imbalance caused by a change of atmospheric composition defines a climate forcing. Climate sensitivity, the eventual global temperature change per unit forcing, is known with good accuracy from Earth's paleoclimate history. However, two fundamental uncertainties limit our ability to predict global temperature change on decadal time scales. First, although climate forcing by human-made greenhouse gases (GHGs) is known accurately, climate forcing caused by changing human-made aerosols is practically unmeasured. Aerosols are fine particles suspended in the air, such as dust, sulfates, and black soot (Ramanathan et al., 2001). Aerosol climate forcing is complex, because aerosols both reflect solar radiation to space (a cooling effect) and absorb solar radiation (a warming effect). In addition, atmospheric aerosols can alter cloud cover and cloud properties. Therefore, precise composition-specific measurements of aerosols and their effects on clouds are needed to assess the aerosol role in climate change. Second, the rate at which Earth's surface temperature approaches a new equilibrium in response to a climate forcing depends on how efficiently heat perturbations are mixed into the deeper ocean. Ocean mixing is complex and not necessarily simulated well by climate models. Empirical data on ocean heat uptake are improving rapidly, but still suffer limitations. We summarize current understanding of this basic physics of global warming and note observations needed to narrow uncertainties. Appropriate measurements can quantify the major factors driving climate change, reveal how much additional global warming is already in the pipeline, and help define the reduction of climate forcing needed to stabilize climate.

  1. Learning about ventilators

    MedlinePLUS

    ... also called a breathing machine or respirator. The ventilator: Is attached to a computer with knobs and buttons that ... Kollef MH. Ventilator-associated complications, including ... al., eds. Murray and Nadel's Textbook of Respiratory Medicine . ...

  2. 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.

  3. Earth's Energy Imbalance and Implications

    E-print Network

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

    2011-01-01

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

  4. 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.

  5. [Independent lung ventilation for asymmetric injury: case report as a demonstration of common challenge].

    PubMed

    Lebedinski?, K M; Artiukov, D A; Borisov, M V; Gromova, T A; Slivin, O A

    2014-01-01

    The article deals with a case of conventional mechanical ventilation in 75 y.o. woman with the background of uncompensated diabetes mellitus, suffering from bilateral pneumonia with predominantly left-sided lesion and severe sepsis. The conventional mechanical ventilation with high pressure levels led to arterial hypoxemia with P/F ratio 52. Independent lung ventilation immediately increased oxygenation up to P/F ratio 225 and evidently improved left lung aeration. The case demonstrates that while applying high pressures to open alveoli, we could not only provoke ventilator-induced lung injury and low cardiac output, but also "squeeze out" pulmonary perfusion from ventilated areas to non-ventilated ones with less intraalveolar pressure levels. PMID:25549491

  6. Ventilator-associated Lung Injury Decreases Lung Ability to Clear Edema in Rats

    Microsoft Academic Search

    E. LECUONA; F. SALDÍAS; A. COMELLAS; K. RIDGE; C. GUERRERO; J. I. SZNAJDER

    1999-01-01

    Ventilator-associated lung injury (VALI) is caused by high tidal volume (V T ) excursions producing mi- crovascular leakage and pulmonary edema. However, the effects of VALI on lung edema clearance and alveolar epithelial cells' Na,K-ATPase function have not been elucidated. We studied lung edema clearance in the isolated-perfused rat lung model after ventilation for 25, 40, and 60 min with

  7. 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.

  8. Clinical ventilation imaging with In-113m aerosol: a comparison with Kr-81m

    SciTech Connect

    Fazio, F. (Instituto S. Raffaele, Milan, Italy); Wollmer, P.; Lavender, J.P.; Barr, M.M.

    1982-04-01

    Following routine ventilation (Kr-81m)/perfusion (Tc-99m) scanning, we obtained aerosol ventilation scans using a solution of In-113m albumin and a settling-bag system. The large-volume settling bag reduces deposition of particles in the large airway by removing large droplets. The patient inhales the aerosol with 5-10 min of tidal breathing, then lung scans are obtained on a gamma camera. The energy of In-113m allows the ventilation scanning to be performed after Tc-99m perfusion scanning. Semiquantitative scoring of regional ventilation showed a close correlation (r = 0.97) between Kr-81m and In-113m aerosol ventilation scans. The aerosol technique gave a slight underestimation of ventilation compared with Kr-81m. This is explained by a slightly reduced penetration of particles to the periphery of the lung in patients with severe obstructive airways disease. In all cases, however, the aerosol did visualize all ventilated regions. The results indicate that this readily available aerosol technique can be useful for clinical ventilation imaging in multiple views.

  9. Ventilatory failure, ventilator support, and ventilator weaning.

    PubMed

    Tobin, Martin J; Laghi, Franco; Jubran, Amal

    2012-10-01

    The development of acute ventilatory failure represents an inability of the respiratory control system to maintain a level of respiratory motor output to cope with the metabolic demands of the body. The level of respiratory motor output is also the main determinant of the degree of respiratory distress experienced by such patients. As ventilatory failure progresses and patient distress increases, mechanical ventilation is instituted to help the respiratory muscles cope with the heightened workload. While a patient is connected to a ventilator, a physician's ability to align the rhythm of the machine with the rhythm of the patient's respiratory centers becomes the primary determinant of the level of rest accorded to the respiratory muscles. Problems of alignment are manifested as failure to trigger, double triggering, an inflationary gas-flow that fails to match inspiratory demands, and an inflation phase that persists after a patient's respiratory centers have switched to expiration. With recovery from disorders that precipitated the initial bout of acute ventilatory failure, attempts are made to discontinue the ventilator (weaning). About 20% of weaning attempts fail, ultimately, because the respiratory controller is unable to sustain ventilation and this failure is signaled by development of rapid shallow breathing. Substantial advances in the medical management of acute ventilatory failure that requires ventilator assistance are most likely to result from research yielding novel insights into the operation of the respiratory control system. PMID:23720268

  10. Local laboratory ventilation devices

    Microsoft Academic Search

    Koenigsberg

    1995-01-01

    This article is a discussion of the ``other`` laboratory ventilation devices described in OSHA`s laboratory standard that could be used in lieu of traditional chemical fume hoods. The reference ``local`` or ``other`` ventilation device is used with little or no information provided as to the type, design, or performance criteria appropriate for specific applications, as was done in excruciating detail

  11. Partial liquid ventilation ventilates better than gas ventilation.

    PubMed

    Fujino, Y; Goddon, S; Chiche, J D; Hromi, J; Kacmarek, R M

    2000-08-01

    Partial liquid ventilation (PLV) improves oxygenation in several models of lung injury. However, PLV has only been compared with conventional gas ventilation (GV) with low PEEP. Both PLV and GV can markedly improve oxygenation when PEEP is set above the lower corner pressure (Plc) on the inspiratory pressure-volume (P-V) curve of the total respiratory system. We questioned if the use of PEEP set above the Plc during PLV and GV would result in similar gas exchange. Lung injury was induced in 12 sheep by saline lavage before randomization to PLV (n = 6) or GV (n = 6). Animals in the PLV group were filled with perflubron (22 ml/kg) until a meniscus at the teeth was observed. Both groups were then ventilated with pressure control (FI(O(2)), 1.0; rate, 20/min; I:E, 1:1) and PEEP (1 cm H(2)O above the Plc on the inspiratory P-V curve). Peak inspiratory pressure (PIP) was limited to 35 cm H(2)O. Animals were ventilated for 5 h and then killed for histologic examinations. All 12 animals survived the 5-h ventilation period. After increasing PEEP above Plc, Pa(O(2)) increased significantly (p < 0.01) in both the GV and the PLV groups, but it did not differ significantly between groups (p = 0.86) at any time during the experiment. Pa(CO(2)) and VD/VT in GV increased markedly throughout the experiment after increasing PEEP (p < 0.001), but there was no significant change in Pa(CO(2)) in PLV (p = 0.13). Mean arterial blood pressure, mean pulmonary artery pressure, pulmonary artery occlusion pressure, and central venous pressure, increased and SVR decreased in GV (p < 0.05). The extent and the severity of lung injury in the dependent regions was greater in the GV group (p < 0.05). Both PLV and GV improved oxygenation, but PLV resulted in better ventilation than GV while preserving lung structure when PEEP was set 1 cm H(2)O above the Plc and PIP limited to 35 cm H(2)O. PMID:10934101

  12. Global imbalances, saving glut and investment strike

    Microsoft Academic Search

    G. Moëc; L. Frey

    2006-01-01

    The present state of the global economy is characterised by persistent and increasingly polarised current account imbalances, in a context of historically low long-term interest rates, which stand below the equilibrium levels proxied by potential growth and trend inflation. A comprehensive analysis by Ben Bernanke1 attributes those two phenomena to one common cause: a global saving glut outside the United

  13. Diabetic Autonomic Imbalance and Glycemic Variability

    PubMed Central

    Fleischer, Jesper

    2012-01-01

    Diabetic autonomic neural imbalance is a severe complication of long-term diabetes patients and may progress to diabetic autonomic neuropathy (DAN). The prevalence of DAN is reported to be between 20 and 70%, depending on the studies. The pathogenesis of DAN remains unresolved. However, emerging evidence suggests that glycemic variability (GV) may be associated with autonomic imbalance in patients with both type 1 and type 2 diabetes. As symptoms are initially weak and uncharacteristic, the condition often remains undiagnosed until late manifestations present themselves. Predominant symptoms may include nausea, vomiting, gastroparesis, involuntary diarrhea, postural hypotension, voiding difficulties, and sexual dysfunction. Analyzing the patterns of heart rate variability carries the potential for detection of autonomic imbalance in the subclinical and asymptomatic stages. In this context, GV may affect the sympathovagal balance by increasing oxidative stress and proinflammatory cytokines. Establishing a GV risk profile could therefore be important in determining risk factors in diabetes patients. This review addresses the issues above and in particular the possible association between diabetic autonomic imbalance and GV. PMID:23063048

  14. 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.

  15. Closed loop mechanical ventilation.

    PubMed

    Wysocki, Marc; Jouvet, Philippe; Jaber, Samir

    2014-02-01

    Mechanical ventilation is a sophisticated technique with very narrow therapeutic ranges i.e. highly efficient and able to keep alive the most severe patients, but with considerable side effects and unwanted complications if not properly and timely used. Computerized protocols, closed loop systems, decision support, all terms which need to be defined, may help making mechanical ventilation safer and more efficient. The present paper will provide a short overview on technical and engineering considerations regarding closed loop controlled ventilation as well as tangible clinical evidences supporting the previous statement. PMID:23564277

  16. 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.

  17. Drillstring Component Mass Imbalance: A Major Source of Downhole Vibrations

    Microsoft Academic Search

    M. W. Dykstra; D. C. K. Chen; T. M. Warren; J. J. Azar

    1996-01-01

    A study consisting of surface and downhole field experiments, theoretical analysis, and numerical modeling has shown that mass imbalance of drillstring components is a major source of downhole lateral vibrations. Factors that contribute to imbalance include bore misalignment, initial curvature, and gradual wear during service. Field experiments were conducted on the surface to quantify drillstring component mass imbalance for modeling

  18. Home Ventilator Guide

    MedlinePLUS

    ... lightweight and portable; they can be mounted on wheelchairs or carts or put on a bedside stand. ... position so I can’t recline in my wheelchair.” – TS, Arizona What is positive pressure ventilation? Positive ...

  19. Perfusion Based Cell Culture Chips

    Microsoft Academic Search

    A. Heiskanen; J. Emnéus; M. Dufva

    2010-01-01

    \\u000a Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium\\u000a composition, long term unattended cultures and tissue like structuring of the cultures. However, as this chapter illustrates,\\u000a many issues remain to be identified regarding perfusion cell culture

  20. Optimising ventilation system performance.

    PubMed

    2008-11-01

    Aquacair believes proper ventilation hygiene is a key tool in ensuring that healthcare premises provide a healthy, safe and comfortable environment, while also making certain, as far as is practicable, that all energy used by ventilation and air conditioning plant is put to good use. Here the company sets out the key priorities for estates and facilities managers seeking to make sure that such plant and equipment performs at optimum efficiency. PMID:19044150

  1. Advances in mechanical ventilation

    Microsoft Academic Search

    Jon Hooper

    1998-01-01

    Conclusion  Although a considerable amount of experimental data exists, preliminary clinical studies of pressure and volume limited ventilation\\u000a have not established its role and benefit in patients with acute lung injury. Indeed, there are no controlled studies that\\u000a prove any form of mechanical ventilation is superior to another in ARDS. Prone positioning should be considered early in the\\u000a course of ARDS,

  2. Earth's Energy Imbalance: Confirmation and Implications

    Microsoft Academic Search

    James Hansen; Larissa Nazarenko; Reto Ruedy; Makiko Sato; Josh Willis; Anthony Del Genio; Dorothy Koch; Andrew Lacis; Ken Lo; Surabi Menon; Tica Novakov; Judith Perlwitz; Gary Russell; Gavin A. Schmidt; Nicholas Tausnev

    2005-01-01

    Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among other forcings, calculates that Earth is now absorbing 0.85 +\\/- 0.15 watts per square meter more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years. Implications include (i) the

  3. 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.

  4. Chronic cholinergic imbalances promote brain diffusion and transport abnormalities.

    PubMed

    Meshorer, Eran; Biton, Inbal E; Ben-Shaul, Yoram; Ben-Ari, Shani; Assaf, Yaniv; Soreq, Hermona; Cohen, Yoram

    2005-06-01

    Cholinergic imbalances occur after traumatic effects and in the initial stages of neurodegenerative diseases, but their long-lasting effects remained largely unexplained. To address this, we used TgS transgenic mice constitutively overexpressing synaptic acetylcholinesterase (AChE-S) and presenting a complex phenotype of progressive neurodeterioration. T1- and T2-weighted magnetic resonance (MR) brain images appeared similar. However, diffusion-weighted MRI showed decreased baseline water apparent diffusion coefficient in the brains of TgS animals. Furthermore, contrast-enhanced MRI after gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) injection demonstrated slower recovery of normal signals in the TgS brains than with controls. Perfusion MR imaging and difference T1 maps calculated from pre- postcontrast T1-weighted MR images indicated accumulation of more Gd-DTPA molecules in the TgS brains than in the parent strain, reflecting impaired blood-brain barrier (BBB) functioning in these transgenic mice. To explore the molecular mechanism(s) underlying these global phenotypes, we performed microarray analysis in the stress-controlling prefrontal cortex of TgS vs. strain-matched wild-type animals. Profound overexpression of numerous ion channels, transporters, and adhesion genes was confirmed by real time RT-PCR tests. Immunohistochemical and immunoblot analyses revealed corresponding increases in the level and cellular distributions of the chloride channel CLCN3 and the water channel AQP4, both of which contribute to BBB maintenance. Our study attributes to balanced cholinergic neurotransmission, a central role in the brain's maintenance of water diffusion and ion transport, and indicates that chronic impairments in this maintenance facilitate neurodeterioration through interference with BBB function. PMID:15923401

  5. Clinical ventilation imaging with /sup 113m/In aerosol: a comparison with /sup 81m/Kr

    SciTech Connect

    Fazio, F.; Wollmer, P.; Lavender, J.P.; Barr, M.M.

    1982-04-01

    Following routine ventilation (/sup 81m/Kr)/perfusion (/sup 99m/Tc) scanning, we obtained aerosol ventilation scans using a solution of /sup 113m/In albumin and a settling-bag system. The large-volume settling bag reduces deposition of particles in the large airway by removing large droplets. The patient inhales the aerosol with 5-10 min of tidal breathing, then lung scans are obtained on a gamma camera. The energy of /sup 113m/In allows the ventilation scanning to be performed after /sup 99m/Tc perfusion scanning. Semiquantitative scoring of regional ventilation showed a close correlation (r . 0.97) between /sup 81m/Kr and /sup 113m/In aerosol ventilation scans. The aerosol technique gave a slight underestimation of ventilation compared with /sup 81m/Kr. This is explained by a slightly reduced penetration of particles to the periphery of the lung in patients with severe obstructive airways disease. In all cases, however, the aerosol did visualize all ventilated regions. The results indicate that this readily available aerosol technique can be useful for clinical ventilation imaging in multiple views.

  6. 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.

  7. Accuracy of pulse oximetry readings in an animal model of low perfusion caused by emerging pneumonia and sepsis

    Microsoft Academic Search

    Helmut D. Hummler; Anja Engelmann; Frank Pohlandt; Josef Högel; Axel R. Franz

    2004-01-01

    Objective To test the effects of low perfusion caused by emerging sepsis on the performance of two new pulse oximetry techniques: Masimo SET in comparison with Nellcor Oxismart XL. Design Cohort study with random allocation of two pulse oximetry devices to two sensor sites. Setting University animal research facility. Subjects Twenty-five adult, anesthetized, ventilated rabbits. Interventions Pneumonia\\/sepsis was induced by

  8. Increased Natural Ventilation Flow Rates through Ventilation Shafts

    E-print Network

    Ray, Stephen D.

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

  9. 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).

  10. Non invasive ventilation.

    PubMed

    Sidhu, U S; Simonds, A K

    2000-04-01

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

  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. Earth's Energy Imbalance: Confirmation and Implications

    NASA Astrophysics Data System (ADS)

    Hansen, James; Nazarenko, Larissa; Ruedy, Reto; Sato, Makiko; Willis, Josh; Del Genio, Anthony; Koch, Dorothy; Lacis, Andrew; Lo, Ken; Menon, Surabi; Novakov, Tica; Perlwitz, Judith; Russell, Gary; Schmidt, Gavin A.; Tausnev, Nicholas

    2005-06-01

    Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among other forcings, calculates that Earth is now absorbing 0.85 +/- 0.15 watts per square meter more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years. Implications include (i) the expectation of additional global warming of about 0.6°C without further change of atmospheric composition; (ii) the confirmation of the climate system's lag in responding to forcings, implying the need for anticipatory actions to avoid any specified level of climate change; and (iii) the likelihood of acceleration of ice sheet disintegration and sea level rise.

  13. Earth's energy imbalance: confirmation and implications.

    PubMed

    Hansen, James; Nazarenko, Larissa; Ruedy, Reto; Sato, Makiko; Willis, Josh; Del Genio, Anthony; Koch, Dorothy; Lacis, Andrew; Lo, Ken; Menon, Surabi; Novakov, Tica; Perlwitz, Judith; Russell, Gary; Schmidt, Gavin A; Tausnev, Nicholas

    2005-06-01

    Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among other forcings, calculates that Earth is now absorbing 0.85 +/- 0.15 watts per square meter more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years. Implications include (i) the expectation of additional global warming of about 0.6 degrees C without further change of atmospheric composition; (ii) the confirmation of the climate system's lag in responding to forcings, implying the need for anticipatory actions to avoid any specified level of climate change; and (iii) the likelihood of acceleration of ice sheet disintegration and sea level rise. PMID:15860591

  14. 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.

  15. Perfusion effects and hydrodynamics.

    PubMed

    Peattie, Robert A; Fisher, Robert J

    2007-01-01

    Biological processes within living systems are significantly influenced by the motion of the liquids and gases to which those tissues are exposed. Accordingly, tissue engineers must not only understand hydrodynamic phenomena, but also appreciate the vital role of those phenomena in cellular and physiologic processes both in vitro and in vivo. In particular, understanding the fundamental principles of fluid flow underlying perfusion effects in the organ-level internal environment and their relation to the cellular microenvironment is essential to successfully mimicking tissue behavior. In this work, the major principles of hemodynamic flow and transport are summarized, to provide readers with a physical understanding of these important issues. In particular, since quantifying hemodynamic events through experiments can require expensive and invasive techniques, the benefits that can be derived from the use of computational fluid dynamics (CFD) packages and neural networking (NN) models are stressed. A capstone illustration based on analysis of the hemodynamics of aortic aneurysms is presented as a representative example of this approach, to stress the importance of tissue responses to flow-induced events. PMID:17195462

  16. 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

  17. Local laboratory ventilation devices

    SciTech Connect

    Koenigsberg, J. [GPR Planners Collaborative, White Plains, NY (United States)

    1995-10-01

    This article is a discussion of the ``other`` laboratory ventilation devices described in OSHA`s laboratory standard that could be used in lieu of traditional chemical fume hoods. The reference ``local`` or ``other`` ventilation device is used with little or no information provided as to the type, design, or performance criteria appropriate for specific applications, as was done in excruciating detail for their fume hood cousins. Equally curious is the fact that no performance test criteria were established for this category of equipment. Therefore, great care must be taken by the designer to determine the specific application intended for each unit specified and confirm that its use is appropriate for the task. In light of these standards, manufacturers have responded with many new and innovative products.

  18. Mass and aerodynamic imbalance of a horizontal axis wind turbine

    SciTech Connect

    Borg, J.P.; Kirchhoff, R.H. [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Mechanical Engineering

    1998-02-01

    It is very common among wind turbines of all designs that a spectral analysis of operating variables, such as yaw motion, torque, or electrical power output has a large concentration of variance at the rotational frequency of the low speed shaft. This spike in the spectrum of the operating variables has come to be known as the once per revolution response or 1P. In addition to this 1P spike, three-bladed wind turbine spectral signatures usually include the harmonic integers 2P and 3P. The two main sources of 1P are mass imbalance in the rotor plane and various aerodynamic performance imbalances of the rotor blades. This paper is dedicated to determining the specific contribution of each of these sources to 1P as well as their effects on the 2P and 3P harmonics. Mass imbalance and aerodynamic imbalance issues are addressed separately so that the relative contribution of each can be quantified. The nonlinear differential equations describing the coupled azimuth and yaw motion with mass imbalance were analytically solved using a perturbation technique. A blade strip element technique was used to determine the effects of aerodynamic imbalance on 1P, 2P, and 3P fluctuations. It was found that 60% of the 1P low-speed shaft torque (LSST) fluctuation is due to mass imbalance and 40% due to aerodynamic imbalance. These results compare quite favorably with the NREL 15 kW Combined Experiment wind turbine data.

  19. 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…

  20. Socially explosive minds: the triple imbalance hypothesis of reactive aggression.

    PubMed

    van Honk, Jack; Harmon-Jones, Eddie; Morgan, Barak E; Schutter, Dennis J L G

    2010-02-01

    The psychobiological basis of reactive aggression, a condition characterized by uncontrolled outbursts of socially violent behavior, is unclear. Nonetheless, several theoretical models have been proposed that may have complementary views about the psychobiological mechanisms involved. In this review, we attempt to unite these models and theorize further on the basis of recent data from psychological and neuroscientific research to propose a comprehensive neuro-evolutionary framework: The Triple Imbalance Hypothesis (TIH) of reactive aggression. According to this model, reactive aggression is essentially subcortically motivated by an imbalance in the levels of the steroid hormones cortisol and testosterone (Subcortical Imbalance Hypothesis). This imbalance not only sets a primal predisposition for social aggression, but also down-regulates cortical-subcortical communication (Cortical-Subcortical Imbalance Hypothesis), hence diminishing control by cortical regions that regulate socially aggressive inclinations. However, these bottom-up hormonally mediated imbalances can drive both instrumental and reactive social aggression. The TIH suggests that reactive aggression is differentiated from proactive aggression by low brain serotonergic function and that reactive aggression is associated with left-sided frontal brain asymmetry (Cortical Imbalance Hypothesis), especially observed when the individual is socially threatened or provoked. This triple biobehavioral imbalance mirrors an evolutionary relapse into violently aggressive motivational drives that are adaptive among many reptilian and mammalian species, but may have become socially maladaptive in modern humans. PMID:20433613

  1. Combating the Small Sample Class Imbalance Problem Using Feature Selection

    Microsoft Academic Search

    Michael Wasikowski; Xue-wen Chen

    2010-01-01

    The class imbalance problem is encountered in real-world applications of machine learning and results in a classifier's suboptimal performance. Researchers have rigorously studied the resampling, algorithms, and feature selection approaches to this problem. No systematic studies have been conducted to understand how well these methods combat the class imbalance problem and which of these methods best manage the different challenges

  2. Improved Performance With Ventilation

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  3. Helmet noninvasive ventilation for weaning from mechanical ventilation.

    PubMed

    Klein, Moti; Weksler, Natan; Bartal, Carmi; Gurman, Gabriel M

    2004-09-01

    We saw a patient who presented with carbon dioxide narcosis and acute respiratory failure due to an exacerbation of chronic obstructive pulmonary disease. We intubated and 12 hours later he had recovered consciousness and could cooperate with noninvasive ventilation, at which point we extubated and used a helmet to provide noninvasive positive-pressure ventilation in assist/control mode, and then during the ventilator-weaning process, pressure support, and finally continuous positive airway pressure. The patient had no complications from the helmet, and he was discharged from intensive care 48 hours after helmet ventilation was initiated. Helmet noninvasive ventilation is a potentially valuable ventilator-weaning method for certain patients. PMID:15329175

  4. A mathematical model of alveolar gas exchange in partial liquid ventilation.

    PubMed

    Suresh, Vinod; Anderson, Joseph C; Grotberg, James B; Hirschl, Ronald B

    2005-02-01

    In partial liquid ventilation (PLV), perfluorocarbon (PFC) acts as a diffusion barrier to gas transport in the alveolar space since the diffusivities of oxygen and carbon dioxide in this medium are four orders of magnitude lower than in air. Therefore convection in the PFC layer resulting from the oscillatory motions of the alveolar sac during ventilation can significantly affect gas transport. For example, a typical value of the Péclet number in air ventilation is Pe approximately 0.01, whereas in PLV it is Pe approximately 20. To study the importance of convection, a single terminal alveolar sac is modeled as an oscillating spherical shell with gas, PFC, tissue and capillary blood compartments. Differential equations describing mass conservation within each compartment are derived and solved to obtain time periodic partial pressures. Significant partial pressure gradients in the PFC layer and partial pressure differences between the capillary and gas compartments (P(C)-Pg) are found to exist. Because Pe> 1, temporal phase differences are found to exist between P(C)-Pg and the ventilatory cycle that cannot be adequately described by existing non-convective models of gas exchange in PLV The mass transfer rate is nearly constant throughout the breath when Pe>1, but when Pe<1 nearly 100% of the transport occurs during inspiration. A range of respiratory rates (RR), including those relevant to high frequency oscillation (HFO) +PLV, tidal volumes (V(T)) and perfusion rates are studied to determine the effect of heterogeneous distributions of ventilation and perfusion on gas exchange. The largest changes in P(C)O2 and P(C)CO2 occur at normal and low perfusion rates respectively as RR and V(T) are varied. At a given ventilation rate, a low RR-high V(T) combination results in higher P(C)O2, lower P(C)CO2 and lower (P(C)-Pg) than a high RR-low V(T) one. PMID:15868788

  5. Proximate sources of population sex imbalance in india.

    PubMed

    Osters, Emily

    2009-05-01

    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

  6. 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 ...

  7. 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

  8. Ventilation heterogeneity in obesity.

    PubMed

    Pellegrino, Riccardo; Gobbi, Alessandro; Antonelli, Andrea; Torchio, Roberto; Gulotta, Carlo; Pellegrino, Giulia Michela; Dellacà, Raffaele; Hyatt, Robert E; Brusasco, Vito

    2014-05-01

    Obesity is associated with important decrements in lung volumes. Despite this, ventilation remains normally or near normally distributed at least for moderate decrements in functional residual capacity (FRC). We tested the hypothesis that this is because maximum flow increases presumably as a result of an increased lung elastic recoil. Forced expiratory flows corrected for thoracic gas compression volume, lung volumes, and forced oscillation technique at 5-11-19 Hz were measured in 133 healthy subjects with a body mass index (BMI) ranging from 18 to 50 kg/m(2). Short-term temporal variability of ventilation heterogeneity was estimated from the interquartile range of the frequency distribution of the difference in inspiratory resistance between 5 and 19 Hz (R5-19_IQR). FRC % predicted negatively correlated with BMI (r = -0.72, P < 0.001) and with an increase in slope of either maximal (r = -0.34, P < 0.01) or partial flow-volume curves (r = -0.30, P < 0.01). Together with a slight decrease in residual volume, this suggests an increased lung elastic recoil. Regression analysis of R5-19_IQR against FRC % predicted and expiratory reserve volume (ERV) yielded significantly higher correlation coefficients by nonlinear than linear fitting models (r(2) = 0.40 vs. 0.30 for FRC % predicted and r(2) = 0.28 vs. 0.19 for ERV). In conclusion, temporal variability of ventilation heterogeneities increases in obesity only when FRC falls approximately below 65% of predicted or ERV below 0.6 liters. Above these thresholds distribution is quite well preserved presumably as a result of an increase in lung recoil. PMID:24651986

  9. 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.

  10. Chromosomal imbalances are uncommon in chagasic megaesophagus

    PubMed Central

    2010-01-01

    Background Chagas' disease is a human tropical parasitic illness and a subset of the chronic patients develop megaesophagus or megacolon. The esophagus dilation is known as chagasic megaesophagus (CM) and one of the severe late consequences of CM is the increased risk for esophageal carcinoma (ESCC). Based on the association between CM and ESCC, we investigated whether genes frequently showing unbalanced copy numbers in ESCC were altered in CM by fluorescence in situ (FISH) technology. Methods A total of 50 formalin-fixed, paraffin-embedded esophageal mucosa specimens (40 from Chagas megaesophagus-CM, and 10 normal esophageal mucosa-NM) were analyzed. DNA FISH probes were tested for FHIT, TP63, PIK3CA, EGFR, FGFR1, MYC, CDKN2A, YES1 and NCOA3 genes, and centromeric sequences from chromosomes 3, 7 and 9. Results No differences between superficial and basal layers of the epithelial mucosa were found, except for loss of copy number of EGFR in the esophageal basal layer of CM group. Mean copy number of CDKN2A and CEP9 and frequency of nuclei with loss of PIK3CA were significantly different in the CM group compared with normal mucosa and marginal levels of deletions in TP63, FHIT, PIK3CA, EGFR, CDKN2A, YES and gains at PIK3CA, TP63, FGFR1, MYC, CDNK2A and NCOA3 were detected in few CM cases, mainly with dilation grades III and IV. All changes occurred at very low levels. Conclusions Genomic imbalances common in esophageal carcinomas are not present in chagasic megaesophagus suggesting that these features will not be effective markers for risk assessment of ESCC in patients with chagasic megaesophagus. PMID:20163722

  11. Evaluation of building ventilation systems.

    PubMed

    Hughes, R T; O'Brien, D M

    1986-04-01

    Over the past several years, NIOSH has responded to health hazard evaluation requests from workers in dozens of office environments. Typically, the employees have complained of headache, eye and upper respiratory tract irritation, dizziness, lethargy and the inability to concentrate. Most often "inadequate ventilation" has been blamed for these complaints. Of paramount importance in the evaluation and correction of these problems is an effective evaluation of the building's ventilation system. Heating, ventilating and air-conditioning conditions that can cause worker stresses include: migration of odors or chemical hazards between building areas; reentrainment of exhaust from building fume hoods or through heat wheels; buildup of microorganisms in the HVAC system components; and poor odor or environmental control due to insufficient "fresh" outdoor air or system heating or cooling malfunction. The purpose of this paper is to provide an overview of building ventilation systems, the ventilation problems associated with poorly designed or operating systems, and the methodology for effectively evaluating system performance. PMID:3706150

  12. Evaluation of building ventilation systems

    SciTech Connect

    Hughes, R.T.; O'Brien, D.M.

    1986-04-01

    Over the past several years, NIOSH has responded to health hazard evaluation requests from workers in dozens of office environments. Typically, the employees have complained of headache, eye and upper respiratory tract irritation, dizziness, lethargy and the inability to concentrate. Most often inadequate ventilation has been blamed for these complaints. Of paramount importance in the evaluation and correction of these problems is an effective evaluation of the building's ventilation system. Heating, ventilating and air-conditioning conditions that can cause worker stresses include: migration of odors or chemical hazards between building areas; reentrainment of exhaust from building fume hoods or through heat wheels; buildup of microorganisms in the HVAC system components; and poor odor or environmental control due to insufficient fresh outdoor air or system heating or cooling malfunction. The purpose of this paper is to provide an overview of building ventilation systems, the ventilation problems associated with poorly designed or operating systems, and the methodology for effectively evaluating system performance.

  13. Recent advances in mechanical ventilation.

    PubMed

    Calfee, Carolyn S; Matthay, Michael A

    2005-06-01

    Important advances have been made over the past decade towards understanding the optimal approach to ventilating patients with acute respiratory failure. Evidence now supports the use of noninvasive positive pressure ventilation in selected patients with hypercapnic respiratory failure and chronic obstructive pulmonary disease, cardiogenic pulmonary edema, and for facilitating the discontinuation of ventilatory support in patients with chronic pulmonary disease. The concept of a lung protective ventilatory strategy has revolutionized the management of the acute respiratory distress syndrome. The process of liberation from mechanical ventilation is becoming more standardized, with evidence supporting daily trials of spontaneous breathing in all suitable mechanically ventilated patients. This article critically reviews the most important recent advances in mechanical ventilation and suggests future directions for further research in the field. PMID:15922687

  14. Impact of Energy Imbalance Tariff on Wind Energy

    SciTech Connect

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

    2007-07-01

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

  15. 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

  16. Ventilation of an hydrofoil wake

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  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

    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(-1)) and eccentric (30° and 120°·s(-1)) 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(-1) ÷ concentric quadriceps 240°·s(-1)). 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(-1)) 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. [Oesophagitis during mechanical ventilation].

    PubMed

    Gastinne, H; Canard, J M; Pillegand, B; Voultoury, J C; Catanzano, A; Claude, R; Gay, R

    1982-10-16

    Twenty-one patients whose condition required mechanical ventilation with nasogastric intubation were investigated for oesophagitis before the 3rd day and on the 15th day of treatment, including endoscopy and biopsy. Lesions of oesophagitis were detected in 14 cases during the initial examination and in 19 cases on the second endoscopy. The course of the lesions varied from one patient to another and appeared to be unrelated to the course of the primary disease. Oesophagitis in these patients is probably due to frequent episodes of gastro-oesophageal reflux encouraged by cough, impaired consciousness and the presence of a tube. Reflux may also be the cause of inapparent and recurrent lung aspiration. PMID:6815616

  19. Mechanical ventilation: invasive versus noninvasive.

    PubMed

    Brochard, L

    2003-11-01

    Mechanical ventilation is the most widely used supportive technique in intensive care units. Several forms of external support for respiration have long been described to assist the failing ventilatory pump, and access to lower airways through tracheostomy or endotracheal tubes had constituted a major advance in the management of patients with respiratory distress. More recently, however, new "noninvasive" ventilation (NIV) techniques, using patient/ventilator interfaces in the form of facial masks, have been designed. The reasons for promoting NIV include a better understanding of the role of ventilatory pump failure in the indications for mechanical ventilation, the development of ventilatory modalities able to work in synchrony with the patient, and the extensive recognition of complications associated with endotracheal intubation and standard mechanical ventilation. NIV has been used primarily for patients with acute hypercapnic ventilatory failure, and especially for acute exacerbation of chronic obstructive pulmonary disease. In this population, the use of NIV is associated with a marked reduction in the need for endotracheal intubation, a decrease in complication rate, a reduced duration of hospital stay and a substantial reduction in hospital mortality. Similar benefits have also been demonstrated in patients with asphyxic forms of acute cardiogenic pulmonary oedema. In patients with primarily hypoxemic forms of respiratory failure, the level of success of NIV is more variable, but major benefits have also been demonstrated in selected populations with no contraindications such as multiple organ failure, loss of consciousness or haemodynamic instability. One important factor in success seems to be the early delivery of noninvasive ventilation during the course of respiratory failure. Noninvasive ventilation allows many of the complications associated with mechanical ventilation to be avoided, especially the occurrence of nosocomial infections. The current use of noninvasive ventilation is growing up, and is becoming a major therapeutic tool in the intensive care unit. PMID:14621115

  20. Ventilator-delivered mask ventilation compared with three standard methods of mask ventilation in a manikin model

    Microsoft Academic Search

    M. B. Tracy; J. Klimek; H. Coughtrey; V. Shingde; G. Ponnampalam; M. Hinder; R. Maheshwari; S. K. Tracy

    2011-01-01

    BackgroundLittle is known regarding the variations in effective ventilation during bag and mask resuscitation with standard methods compared with that delivered by ventilator-delivered mask ventilation (VDMV).AimTo measure the variations in delivered airway pressure, tidal volume (TV), minute ventilation (MV) and inspiratory time during a 3-min period of mask ventilation comparing VDMV with three commonly used hand-delivered methods of bag and

  1. 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.

  2. Right axillary and femoral artery perfusion with mild hypothermia for aortic arch replacement

    PubMed Central

    2014-01-01

    Objectives Aortic arch replacement is associated with increased mortality and morbidity especially in acute type-A aortic dissection. Although hypothermic circulatory arrest with selective antegrade cerebral perfusion has been widely used because of its excellent cerebral protection, its optimal perfusion characteristics are unknown. The present study investigates clinical results obtained after perfusion method modification and temperature management during cardiopulmonary bypass (CPB). Methods Between July 2010 and August 2012, 16 consecutive adult patients (mean age 50.0 yr?±?14.1 yr, range 25 yr to 73 yr, 12 males, 4 females) who presented with acute Stanford type-A aortic dissection underwent aortic arch replacement (total arch, n?=?11; hemiarch, n?=?5) under mild hypothermia (31.1°C?±?1.5°C) with right axillary and femoral artery perfusion. Results The mean CPB time was 201 min?±?53 min, and the mean myocardial ischemic time was 140 min?±?42 min. The mean selective cerebral perfusion time was 80 min?±?16 min, and the mean lower-body circulatory arrest time was 20 min?±?13 min. No patient death occurred within 30 post-operative days. The following details were observed: new post-operative permanent neurologic deficit in 1 patient (6.3%), temporary neurologic deficit in 2 patients (12.5%), acute renal dysfunction (creatinine level?>?230 umol/L) in 3 patients (18.8%) and mechanical ventilation?>?72 h in 5 patients (31.2%). Conclusions Aortic arch replacement for acute type-A aortic dissection under mild hypothermia with right axillary and femoral artery perfusion could be safely performed in the patient cohort. PMID:24885031

  3. Intestinal perfusion monitoring using photoplethysmography

    PubMed Central

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

    2013-01-01

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

  4. 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.

  5. Effect of oxygen-derived free radicals on arachidonic acid turnover in isolated perfused rat lung

    SciTech Connect

    Jones, R.; Otani, H.; Das, D.K.

    1986-05-01

    Turnover of arachidonic acid in lung was studied by perfusing an isolated and ventilated rat lung in the presence of (/sup 14/C)-arachidonic acid for 30 min. Oxygen-derived free radicals were generated within the pulmonary circulation by the action of xanthine oxidase (XO) (0.1 ..mu../ml) on hypoxanthine (0.1 ..mu..mol/ml). Lung was also preperfused in the presence or absence of superoxide dismutase (SOD) (5 ..mu..g/ml) and catalase (5 ..mu..g/ml) prior to the addition of radiolabeled arachidonic acid and free radical generating system. After the perfusion was over, several biopsies were obtained and phospholipids were extracted and separated from one of the biopsies. Individual phospholipids were compared with known standards and counted for radioactivity. An appreciable amount of radioactivity was found in total phospholipids and in phosphatidyl choline and phosphatidyl inositol fractions in control lungs. Some radioactivity was also noticed in phosphatidyl ethanolamine fraction. The isotopic incorporation was significantly inhibited when lung was perfused in the presence of hypoxanthine and XO. The incorporation of (/sup 14/C)-radioactivity was restored to the control levels when lung was preperfused with SOD and catalase. These results suggest that oxygen radicals inhibit the arachidonic acid turnover in isolated and perfused rat lung.

  6. 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

  7. A new infant oscillatory ventilator.

    PubMed

    Chakrabarti, M K; Holdcroft, A; Sapsed-Byrne, S; Whitwam, J G

    1990-03-01

    A new, simple and inexpensive oscillatory ventilator is described in which a rotating jet mounted in the breathing duct generates cyclically positive and negative pressures in the airway with a sinusoidal flow waveform. Unlike conventional oscillatory ventilators it is free from restrictions to inspiratory or expiratory gas flows and open to atmosphere at all times, making it intrinsically a safe system for ventilation. A prototype rotating jet oscillatory ventilator designed for application in infants was evaluated in rabbits (mean weight 3.8 kg). The positive peak and mean airway pressures were significantly less during oscillatory ventilation at 300 and 420 b.p.m. compared with normal and high frequency positive pressure ventilation at 30 and 300 b.p.m., respectively, while maintaining blood-gas tensions within the normal range. An increase in the oscillatory frequency from 300 to 420 b.p.m. provided no further benefit in terms of airway pressure, tidal volume or blood-gas tensions. PMID:2109628

  8. Mechanical ventilation for severe asthma.

    PubMed

    Leatherman, James

    2015-06-01

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

  9. Effect on ventilation of papaverine administered to the brain stem of the anaesthetized cat.

    PubMed Central

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

    1991-01-01

    1. To investigate whether cerebral vasodilatation by itself contributes to the decrease in ventilation as found during brain stem hypoxia the role of cerebral vasodilatation on minute ventilation was investigated in twelve cats anaesthetized with alpha-chloralose-urethane. 2. Cerebral vasodilatation in the medulla oblongata was produced by adding papaverine to the blood perfusing the brain stem. 3. Papaverine at concentrations of 10-35 micrograms per millilitre of blood had an appreciable depressant effect on ventilation. At a concentration of 14.3 micrograms ml-1 the depression in ventilation averaged 0.7 +/- 0.1 l min-1. 4. The ventilatory response to stepwise changes in papaverine concentration could be adequately described with a single exponential function with a time delay. 5. The time constant of the ventilatory response following a step increase in papaverine concentration (134 +/- 15 s) was longer than that of the step decrease (105 +/- 10 s) in concentration (P = 0.034). The time delays of the ventilatory response (88 +/- 21 s and 53 +/- 8 s respectively) were not significantly different (P = 0.126). 6. The ventilatory response to stimulation of the peripheral chemoreceptors by hypoxia and of the central chemoreceptors by hypercapnia was not impaired by papaverine. 7. The results support the hypothesis that cerebral vasodilatation by itself contributes to the decrease in ventilation by brain stem hypoxia. PMID:1822533

  10. Effect of angiotensin II-induced changes in perfusion flow rate on chlorothiazide transport in the isolated perfused rat kidney

    Microsoft Academic Search

    David E. Smith; Stephanie Guillard; Carlos A. Rodriguez

    1992-01-01

    Angiotensin II was used as a probe to study the effect of changes in perfusate flow rate on the renal clearance parameters of chlorothiazide in the isolated perfused rat kidney. Perfusion studies were performed in five rats with no angiotensin II present in the perfusate and in five rats with a 1–4 ng\\/min infusion of angiotensin II into the perfusate.

  11. Myocardial perfusion imaging using contrast echocardiography.

    PubMed

    Pathan, Faraz; Marwick, Thomas H

    2015-01-01

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

  12. Effect of positive end-expiratory pressure on splanchnic perfusion in acute lung injury

    Microsoft Academic Search

    P. Kiefer; S. Nunes; P. Kosonen; J. Takala

    2000-01-01

    Objective: To evaluate the acute effects of an increased positive end-expiratory pressure (PEEP) on splanchnic tissue perfusion.?Design: Clinical prospective study.?Setting: Intensive care unit in a university clinic.?Patients: Six patients with severe acute lung injury (ALI) requiring mechanical ventilation. All patients had bilateral infiltrates\\u000a in chest X-ray, PaO2\\/FiO2 Interventions: PEEP was increased by 5 cmH2O from a clinically selected PEEP level

  13. A randomized comparison of total extracorporeal CO 2 removal with conventional mechanical ventilation in experimental hyaline membrane disease

    Microsoft Academic Search

    K. L. Dorrington; K. M. McRae; J.-P. Gardaz; M. S. Dunnill; M. K. Sykes; A. R. Wilkinson

    1989-01-01

    Apnoeic oxygenation (AO) combined with extracorporeal CO2 removal (ECCO2R), using venovenous perfusion across a membrane area of 0.1m2 has been shown to be feasible in six healthy anaesthetized rabbits. In a further twelve rabbits, ECCO2R has been randomly compared with conventional mechanical ventilation (CMV) following saline lavage to induce respiratory failure. Blood gases were maintained for up to 6h within

  14. Adaptive Grid Refinement Using Cell-Level and Global Imbalances

    NASA Astrophysics Data System (ADS)

    Chang, S.; Haworth, D. C.

    1997-02-01

    A methodology for local solution-adaptive mesh refinement in computational fluid dynamics (CFD) using cell-level and global kinetic energy balances is formulated and tested. Results are presented for two two-dimensional steady incompressible laminar benchmark problems: a lid-driven cavity (Reynolds number Re=1000) and a backward-facing step (Re=400). It is demonstrated that local kinetic energy imbalance correlates with local solution accuracy, that normalized global imbalance is an appropriate criterion for halting mesh refinement and that a specified level of accuracy is realized at lower computational effort using local refinement compared with a uniform finer mesh.

  15. 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).

  16. Ageing and Fiscal Imbalances Across Generations: Concepts of Measurement

    Microsoft Academic Search

    Robert Fenge; Martin Werding

    2003-01-01

    In the literature, several approaches have been taken to measure the impact of demographic ageing on public pension schemes, with particular attention being paid to potential fiscal imbalances across the generations involved in demographic transition. In this paper, we review three of these measures - viz., “net pension liabilities” and “general government fiscal balances” as suggested by the OECD, as

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

    Microsoft Academic Search

    Bibler

    1997-01-01

    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

  18. The Euro’s Effect on Trade Imbalances

    Microsoft Academic Search

    Helge Berger; Volker Nitsch

    2010-01-01

    When does trade become a one-way relationship? We study bilateral trade balances for a sample of 18 European countries over the period from 1948 through 2008. We find that, with the introduction of the euro, trade imbalances among euro area members widened considerably, even after allowing for permanent asymmetries in trade competitiveness within pairs of countries or in the overall

  19. IQ Gain Imbalance Measurement for OFDM Based Wireless Communication Systems

    Microsoft Academic Search

    H. Arslan

    2006-01-01

    In this paper, IQ gain imbalance for OFDM based multi-carrier modulation techniques is studied. The effect of gain mismatch in IQ modulator will be investigated on the system and receiver performance. Estimation and measurement of IQ gain mismatch at the receiver using baseband digital signal processing techniques will be discussed

  20. Automated PLAT Trading Agent Using Order Imbalance in Volume

    Microsoft Academic Search

    Harish K Subramanian

    Volume of trades and order book volume imbalances have long been established as important criteria in evaluating portfolios and long term investment strategies. The hypothesis being evaluated in this project is that it is an essential component of intraday trading strategies - important enough to be effectively used exclusively as an indicator of the market behavior. The design of a

  1. October 7, 2002 Order Imbalance and Individual Stock Returns

    E-print Network

    Kearns, Michael

    there is generally a large amount of trading interest on a given day, which is about evenly distributed across buyers evidence consistent with these implications. We also find that imbalance-based trading strategies yield sta has been devoted to exploring the relation between stock price movements and trading activity, where

  2. 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...

  3. Global stabilization of the spinning top with mass imbalance

    Microsoft Academic Search

    Kai-Yew Lum; Dennis S. Bernstein; Vincent T. Coppola

    1995-01-01

    We consider the stabilization of a top with known imbalance to the sleeping motion. We first define the sleeping motion and show that it is a solution of the equations of motion of a balanced top. In the general case where the top is unbalanced, we derive two families of control laws that globally asymptotically stabilize a top with known

  4. Modeling perfusion in the cerebral vasculature

    Microsoft Academic Search

    T. David; S. Moore

    2008-01-01

    The constant perfusion of a human organ with nutrients and oxygen demands a robust regulatory mechanisms in the face of normal day-to-day pressure variations in the vasculature. The brain, in a similar manner to the heart requires this mechanism to be extremely quick acting, relative to other ways of altering perfusion such as varying systemic blood pressure, since oxygen depravation

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

    PubMed Central

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

    2012-01-01

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

  6. 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.

  7. Perfusion induced hyperthermia for oncologic therapy with cardiac and cerebral protection.

    PubMed

    Hemmila, Mark R; Foley, David S; Casetti, Alfredo V; Soldes, Oliver S; Hirschl, Ronald B; Bartlett, Robert H

    2002-01-01

    Cancer can be preferentially damaged and killed at temperatures above 41.0 degrees C. However, the heart and brain malfunction at this temperature, limiting the application of systemic hyperthermia in the treatment of metastatic cancer. We created a hyperthermic perfusion system that maximizes the temperature differential produced and extends the safe hyperthermic time. Mongrel dogs were anesthetized and mechanically ventilated. Temperature probes were placed in the rectum, bladder, peritoneal cavity, proximal aorta, pulmonary artery, and right tympanic canal. Venoarterial perfusion was instituted and the perfusate was warmed to 44 to 45 degrees C. The dogs' rectal temperature was elevated to > or = 42 degrees C for 4 hours. A small amount of venous blood was cooled to 28 to 30 degrees C and reperfused into the right atrium to maintain the pulmonary artery temperature < or = 38 degrees C. At the end of the perfusion, the dogs were decannulated, recovered, and returned to their cages for observation. Ten of 11 dogs survived the operative procedure, and no neurologic deficits were observed. The rectal temperature was successfully elevated to > or = 42 degrees C for 4 hours while maintaining the heart and brain at < or = 38 degrees C. Moderate serum biochemical changes were observed postprocedure. However, only the aspartate transaminase and alkaline phosphatase levels remained elevated above both the baseline and canine reference values by day 7. Lower abdominal and pelvic hyperthermia at 42 degrees C can be safely produced and maintained for 4 hours using an extracorporeal perfusion circuit, while protecting the heart and brain from temperature elevation. PMID:12141462

  8. Inhaled prostacyclin and high-frequency oscillatory ventilation in a premature infant with respiratory syncytial virus-associated respiratory failure.

    PubMed

    Gupta, Manoj; Guertin, Stephen; Martin, Steve; Omar, Said

    2012-08-01

    In a 29-day-old premature infant with respiratory syncytial virus (RSV) pneumonia, we have shown an additive effect of high-frequency oscillatory ventilation (HFOV) and continuous inhalation of prostacyclin (iPGI(2)) with improvement of ventilation and oxygenation. The addition of continuous inhaled iPGI(2) to HFOV was beneficial in the treatment of hypoxemic respiratory failure owing to RSV-associated pneumonia. The improvement in alveolar recruitment by increasing lung expansion by HFOV along with less ventilation-perfusion mismatch by iPGI(2) appears to be responsible for the synergistic effect and favorable clinical outcome. We conclude that the combined therapy of HFOV and continuous inhaled iPGI(2) may be considered in RSV-associated hypoxemic respiratory failure in pediatric patients. PMID:22753555

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

    E-print Network

    Marin, Manuel

    1996-01-01

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

  10. Bi-level home ventilators for non invasive positive pressure ventilation

    Microsoft Academic Search

    R. Scala

    Bi-level home ventilators for non invasive positive pressure ventilation. R. Scala. With the widespread use of non-invasive positive pressure mechanical ventilation, great efforts have been made to produce machines, the bi-level home ventilators, which are less sophisticated, cheaper and able to better compensate air leaks with respect to the domiciliary vol- ume-target machines and the traditional ventilators used in intensive

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

    PubMed

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

    2015-07-01

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

  12. Measurement of respiratory function: ventilation

    Microsoft Academic Search

    Iain Campbell; James Waterhouse

    2005-01-01

    Ventilation is traditionally assessed by measuring static lung volumes (e.g. total lung capacity, vital capacity). Measurement of functional residual capacity requires the use of a tracer gas such as helium or nitrogen. The results are compared with standards for age, weight and height. For clinical purposes, by the bedside, forced expiratory volume in 1 second (FEV1) and forced vital capacity

  13. Ventilation survey manual: Revision 1

    SciTech Connect

    Miller, G.

    1989-05-01

    This manual is written for Health and Safety Technicians at the Lawrence Livermore National Laboratory (LLNL). The objective of this manual is to assure that ventilation systems are thoroughly evaluated in a consistent manner throughout the life spans of the systems. Through lecture and practical experience, Industrial Hygienists train Technicians to evaluate ventilation systems. This manual should be used as a reference by trained Technicians in their independent surveys of ventilation systems. There is a surprising amount of turmoil in the field of industrial ventilation. The criteria for defining the acceptable velocities of air entering through the pass-out doors of glove boxes, for example, are under review at this time. In addition, the microchip revolution has led to a number of instruments with digital read-out displays and one instrument with a data logger. Future instruments may have both analog and digital displays and the ability to make real-time calibrations. Thus, this manual will need to be revised periodically to keep up with changes in theory and technology. 10 refs., 16 figs., 2 tabs.

  14. The basis and basics of mechanical ventilation.

    PubMed

    Bone, R C; Eubanks, D H

    1991-06-01

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

  15. Analytic one dimensional transient conduction into a living perfuse/non-perfuse two layer composite system

    NASA Astrophysics Data System (ADS)

    Becker, Sid

    2012-02-01

    This study considers a two layer composite system in which transport within one layer is governed by pure diffusion and transport within the second layer is governed by both perfusion and diffusion. Previous solutions to this situation have approximated the layer without perfusion by using a small non-zero value of the perfusion coefficient. This study provides an exact one dimensional solution to a two layer composite system in which one layer has a high perfusion rate and the adjacent layer has a zero perfusion value. During the solution development, which uses the separation of variables method, the parametric constants and the perfusion term are coupled directly to the transient component of the governing equation. This is done to isolate the spatially diffusive term. The non-dimensional solution is developed symbolically and an example test case is provided to show the transient behavior of the solution using the first 20 terms of the series.

  16. 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.

  17. Constrained Quadratic Programming, Active Control of Rotating Mass Imbalance

    NASA Astrophysics Data System (ADS)

    Manchala, D. W.; Palazzolo, A. B.; Kascak, A. F.; Montague, G. T.; Brown, G. V.

    1997-09-01

    Jet engines may experience severe vibration due to the sudden imbalance caused by blade failure. The current research investigates employment of piezoelectric actuators to suppress this using active vibration control. This requires identification of the source of the vibrations via an expert system, determination of the required phase angles and amplitudes for the correction forces, and application of the desired control signals to the piezoelectric actuators. Correction forces may exceed the physical limitations of the actuators; hence results of “constrained force” quadratic programming, least squares and multi-point correction algorithms will be compared. It is demonstrated that simply scaling down the least squares predicted correction forces to satisfy the actuator saturation constraints does not necessarily yield optimal reductions in vibration. In this paper test results are shown for sudden imbalance, and the computational time requirements and balancing effectiveness for the various approaches are compared.

  18. Global Imbalances and the Financial Crisis: Products of Common Causes

    Microsoft Academic Search

    Maurice Obstfeld; Kenneth Rogoff

    2009-01-01

    This paper makes a case that the global imbalances of the 2000s and the recent global financial crisis are intimately connected. Both have their origins in economic policies followed in a number of countries in the 2000s and in distortions that influenced the transmission of these policies through U.S. and ultimately through global financial markets. In the U.S., the interaction

  19. Enzymic imbalance in serine metabolism in rat hepatomas.

    PubMed Central

    Snell, K; Weber, G

    1986-01-01

    The activity of 3-phosphoglycerate dehydrogenase was high in tissues of high cell-renewal capacity, and was increased in neonatal and regenerating liver and, more markedly, in hepatomas. Serine hydroxymethyltransferase activity was present in hepatomas, whereas other enzymes of serine utilization (serine dehydratase and serine aminotransferase) were absent. This enzymic imbalance couples serine biosynthesis preferentially to nucleotide precursor formation in cancer cells. PMID:3082329

  20. Chronic cholinergic imbalances promote brain diffusion and transport abnormalities

    Microsoft Academic Search

    Eran Meshorer; Inbal E. Biton; Yoram Ben-Shaul; Shani Ben-Ari; Yaniv Assaf; Hermona Soreq; Yoram Cohen

    2005-01-01

    Cholinergic imbalances occur after traumatic effects and in the initial stages of neuro- degenerative diseases, but their long-lasting effects remained largely unexplained. To address this, we used TgS transgenic mice constitutively overexpress- ing synaptic acetylcholinesterase (AChE-S) and pre- senting a complex phenotype of progressive neuro- deterioration. T1- and T2-weighted magnetic resonance (MR) brain images appeared similar. How- ever, diffusion-weighted MRI

  1. The mechanical ventilator: past, present, and future.

    PubMed

    Kacmarek, Robert M

    2011-08-01

    The use of ventilatory assistance can be traced back to biblical times. However, mechanical ventilators, in the form of negative-pressure ventilation, first appeared in the early 1800s. Positive-pressure devices started to become available around 1900 and today's typical intensive care unit (ICU) ventilator did not begin to be developed until the 1940s. From the original 1940s ventilators until today, 4 distinct generations of ICU ventilators have existed, each with features different from that of the previous generation. All of the advancements in ICU ventilator design over these generations provide the basis for speculation on the future. ICU ventilators of the future will be able to integrate electronically with other bedside technology; they will be able to effectively ventilate all patients in all settings, invasively and noninvasively; ventilator management protocols will be incorporated into the basic operation of the ventilator; organized information will be presented instead of rows of unrelated data; alarm systems will be smart; closed-loop control will be present on most aspects of ventilatory support; and decision support will be available. The key term that will be used to identify these future ventilators will be smart! PMID:21801579

  2. Optimization and control of perfusion cultures using a viable cell probe and cell specific perfusion rates

    Microsoft Academic Search

    Jason E. Dowd; Anthea Jubb; K. Ezra Kwok; James M. Piret

    2003-01-01

    Consistent perfusion culture production requires reliable cell retention and control of feed rates. An on-line cell probe\\u000a based on capacitance was used to assay viable biomass concentrations. A constant cell specific perfusion rate controlled medium\\u000a feed rates with a bioreactor cell concentration of ?5 106 cells mL-1. Perfusion feeding was automatically adjusted based on the cell concentration signal from the

  3. Prism adaptation improves postural imbalance in neglect patients.

    PubMed

    Nijboer, Tanja C W; Olthoff, Liselot; Van der Stigchel, Stefan; Visser-Meily, Johanna M A

    2014-03-26

    Several studies have found a negative relation between neglect and postural imbalance. The aim of the current study was to investigate the influence of a single session of prism adaptation on balance [i.e. mediolateral and anteroposterior center of pressure (CoP)] and postural sway (i.e. mean variance of displacement in horizontal and vertical planes) in neglect patients. CoP and postural sway were measured in a single session while sitting unaided on a Wii Balance Board. With respect to mediolateral as well as anteroposterior CoP, there was an improvement in postural imbalance after prism adaptation when measurements were performed with the eyes open, but not with the eyes closed. With respect to postural sway, only horizontal sway was significantly reduced after prism adaptation, but no changes were found for vertical sway. Prism adaptation may produce the recalibration of disturbed representation of space as well as higher-level representations of extrapersonal and internal body space (i.e. internal body midline). Given the important role of postural control in daily life functioning in stroke patients, this study might open possibilities for a successful rehabilitation procedure to alleviate deficits in postural imbalance. PMID:24488029

  4. 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

  5. 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.

  6. Calculation of the Respiratory Modulation of the Photoplethysmogram (DPOP) Incorporating a Correction for Low Perfusion

    PubMed Central

    Addison, Paul S.; Wang, Rui; McGonigle, Scott J.; Bergese, Sergio D.

    2014-01-01

    DPOP quantifies respiratory modulations in the photoplethysmogram. It has been proposed as a noninvasive surrogate for pulse pressure variation (PPV) used in the prediction of the response to volume expansion in hypovolemic patients. The correlation between DPOP and PPV may degrade due to low perfusion effects. We implemented an automated DPOP algorithm with an optional correction for low perfusion. These two algorithm variants (DPOPa and DPOPb) were tested on data from 20 mechanically ventilated OR patients split into a benign “stable region” subset and a whole record “global set.” Strong correlation was found between DPOP and PPV for both algorithms when applied to the stable data set: R = 0.83/0.85 for DPOPa/DPOPb. However, a marked improvement was found when applying the low perfusion correction to the global data set: R = 0.47/0.73 for DPOPa/DPOPb. Sensitivities, Specificities, and AUCs were 0.86, 0.70, and 0.88 for DPOPa/stable region; 0.89, 0.82, and 0.92 for DPOPb/stable region; 0.81, 0.61, and 0.73 for DPOPa/global region; 0.83, 0.76, and 0.86 for DPOPb/global region. An improvement was found in all results across both data sets when using the DPOPb algorithm. Further, DPOPb showed marked improvements, both in terms of its values, and correlation with PPV, for signals exhibiting low percent modulations. PMID:25177348

  7. Microcirculation Perfusion Monitor on the Back of the Health Volunteers

    PubMed Central

    Li, Yanqi; Li, Xiaomei; Zhou, Dan; Wang, Kang; Liu, Yangyang; Guo, Yi; Qiu, Shuang; Zhai, Tianchen; Liu, Shuang; Liu, Jingjing; Ming, Dong

    2013-01-01

    Objective. To observe the dermal microcirculation blood perfusion characterization of meridians channels (acupoints). Methods. 20 healthy human subjects were monitored using Pericam Perfusion Speckle Imager (PSI) for the changes in dermal microcirculation blood perfusion on governor meridian and other respective dermal regions as a control. Result. The microcirculation blood perfusion on Governor Meridian is higher than its control area. Conclusion. The dermal microcirculation blood perfusion on certain parts of Governor Meridian of healthy human subjects showed specifics. PMID:24371463

  8. Multi-delay Arterial Spin Labeling Perfusion MRI in Moyamoya Disease – Comparison with CT Perfusion Imaging

    PubMed Central

    Wang, Rui; Yu, Songlin; Alger, Jeffry R.; Zuo, Zhentao; Chen, Juan; Wang, Rong; An, Jing; Wang, Bo; Zhao, Jizong; Xue, Rong; Wang, Danny JJ

    2014-01-01

    Purpose To present a multi-delay multi-parametric pseudo-continuous ASL (pCASL) protocol that offers simultaneous measurements of cerebral blood flow (CBF), arterial transit time (ATT) and arterial cerebral blood volume (aCBV) and to evaluate its accuracy by comparison with CT perfusion in moyamoya disease. Materials and Methods A 4 post-labeling delay (PLD) pCASL protocol was applied on 17 patients with moyamoya disease who also underwent CT perfusion imaging. ATT was estimated using the multi-delay protocol and included in the calculation of CBF. ASL and CT perfusion images were rated for lesion severity/conspicuity. Pearson correlation coefficients were calculated across voxels between the two modalities in grey and white matter of each subject respectively and between normalized mean values of ASL and CT perfusion measures in major vascular territories. Results Significant associations between ASL and CT perfusion were detected using subjective ratings, voxel-wise analysis in grey and white matter and region of interest (ROI) based analysis of normalized mean perfusion. The correlation between ASL CBF and CT perfusion was improved using the multi-delay pCASL protocol compared to CBF acquired at a single PLD of 2 s (p<0.05). Conclusion There is a correlation between perfusion data from ASL and CT perfusion imaging in patients with moyamoya disease. Multi-delay ASL can improve CBF quantification, which could be a prognostic imaging biomarker in patients with moyamoya disease. PMID:24557051

  9. 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.

  10. Brain perfusion imaging : performance and accuracy 

    E-print Network

    Zhu, Fan

    2013-07-02

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

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

    PubMed Central

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

    2013-01-01

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

  12. Improved exercise myocardial perfusion during lidoflazine therapy

    SciTech Connect

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

    1983-11-01

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

  13. Hepatic perfusion imaging: concepts and application.

    PubMed

    Haider, Masoom A; Farhadi, Farzin A; Milot, Laurent

    2010-08-01

    Hepatic perfusion imaging with magnetic resonance (MR) imaging is an emerging technique for quantitative assessment of diffuse hepatic disease and hepatic lesion blood flow. The principal method that has been used is based on T1 dynamic contrast-enhanced MR imaging. Perfusion imaging shows promise in the assessment of tumor therapy response, staging of liver fibrosis, and evaluation of hepatocellular carcinoma. The future standardization of imaging protocols and MR imaging pulse sequences will allow for broader clinical applications. PMID:21094450

  14. Interactive Visual Analysis of Perfusion Data

    Microsoft Academic Search

    Steffen Oeltze; Helmut Doleisch; Helwig Hauser; Philipp Muigg; Bernhard Preim

    2007-01-01

    Abstract—Perfusion data are dynamic,medical image data which characterize the regional blood flow in human,tissue. These data have a great potential in medical diagnosis, since diseases can be better discriminated and detected at an earlier stage compared to static image data. The wide-spread use of perfusion data is hampered by the lack of efficient evaluation methods. For each voxel, a time-intensity

  15. Quantitative Assessment of Pulmonary Shunt and Ventilation-Perfusion Mismatch without a Blood Sample

    Microsoft Academic Search

    Bram W. Smith; Stephen E. Rees; Dan S. Karbing; S. Kjaergaard; Steen Andreassen

    2007-01-01

    The automated lung parameter estimator (ALPE) system for quantitatively assessing pulmonary gas exchange in clinical practice has been shown to be useful for diagnosing lung dysfunction and monitoring treatment. However, the method requires at least one blood sample, which is routine in intensive care, but not readily available in many other hospital departments. This study investigates the feasibility of using

  16. 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.

  17. In Vivo MR Imaging of Pulmonary Perfusion and Gas Exchange in Rats via Continuous Extracorporeal Infusion of Hyperpolarized 129Xe

    PubMed Central

    Cleveland, Zackary I.; Möller, Harald E.; Hedlund, Laurence W.; Nouls, John C.; Freeman, Matthew S.; Qi, Yi; Driehuys, Bastiaan

    2012-01-01

    Background Hyperpolarized (HP) 129Xe magnetic resonance imaging (MRI) permits high resolution, regional visualization of pulmonary ventilation. Additionally, its reasonably high solubility (>10%) and large chemical shift range (>200 ppm) in tissues allow HP 129Xe to serve as a regional probe of pulmonary perfusion and gas transport, when introduced directly into the vasculature. In earlier work, vascular delivery was accomplished in rats by first dissolving HP 129Xe in a biologically compatible carrier solution, injecting the solution into the vasculature, and then detecting HP 129Xe as it emerged into the alveolar airspaces. Although easily implemented, this approach was constrained by the tolerable injection volume and the duration of the HP 129Xe signal. Methods and Principal Findings Here, we overcome the volume and temporal constraints imposed by injection, by using hydrophobic, microporous, gas-exchange membranes to directly and continuously infuse 129Xe into the arterial blood of live rats with an extracorporeal (EC) circuit. The resulting gas-phase 129Xe signal is sufficient to generate diffusive gas exchange- and pulmonary perfusion-dependent, 3D MR images with a nominal resolution of 2×2×2 mm3. We also show that the 129Xe signal dynamics during EC infusion are well described by an analytical model that incorporates both mass transport into the blood and longitudinal relaxation. Conclusions Extracorporeal infusion of HP 129Xe enables rapid, 3D MR imaging of rat lungs and, when combined with ventilation imaging, will permit spatially resolved studies of the ventilation-perfusion ratio in small animals. Moreover, EC infusion should allow 129Xe to be delivered elsewhere in the body and make possible functional and molecular imaging approaches that are currently not feasible using inhaled HP 129Xe. PMID:22363613

  18. 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.

  19. Measurement of human pancreatic perfusion using dynamic computed tomography with perfusion imaging.

    PubMed

    Miles, K A; Hayball, M P; Dixon, A K

    1995-05-01

    Absolute quantification of pancreatic perfusion in man has been extremely difficult to date. This paper describes a relatively simple application of dynamic computed tomography to provide perfusion imaging of the human pancreas. Values for perfusion in eight normal pancreases ranged between 1.25 and 1.66 ml min-1 ml-1 (mean: 1.52 ml min-1 ml-1). Increased perfusion values were present in a patient with an islet cell tumour (overall perfusion 2.11 ml min-1 ml-1) and a patient with Wilson's disease (3.43 ml min-1 ml-1). Pancreatic perfusion was reduced in a patient with diabetes (0.60 ml min-1 ml-1) and in a failing pancreatic transplant (0.97 ml min-1 ml-1). The combination of functional information and good spatial detail afforded by computed tomography (CT) perfusion imaging means the technique is well suited for the evaluation of the human pancreas. It is currently the only technique which allows non-invasive absolute quantification of pancreatic perfusion. PMID:7788231

  20. High-frequency perfusion fluorometry: a new technique to assess bronchial mucosa blood perfusion

    NASA Astrophysics Data System (ADS)

    Bottiroli, Giovanni F.; Ramponi, Roberta; Croce, Anna C.; Rescigno, Giuseppe; Nazari, Stefano; Zonta, Aris

    1992-05-01

    A new method to estimate airway mucosa blood perfusion is proposed based on the fluorescein perfusion fluorometry principles, which allows both high temporal resolution and high sensitivity measurements to be performed. Preliminary results were obtained on different conditions of rat trachea vascularization, which provide interesting perspectives for an application to the bronchial ischemia problems in lung transplantation.

  1. CFD applications in tunnel ventilation analysis

    SciTech Connect

    Ray, R.E. Jr.; Zigh, A.

    1999-07-01

    Longitudinal ventilation systems in transit and rail tunnels are typically analyzed by one dimensional ventilation network simulation models, such as the Subway Environment Simulation (SES) program. However, in recent years computational fluid dynamics (CFD) modeling has been utilized in conjunction with one-dimensional ventilation network programs to study ventilation systems for large volume spaces such as transit stations and rail overbuilds, as well as for vehicular tunnels. CFD uses numerical methods to simulate complex fluid flow phenomena in three dimensions to predict the distribution of velocity, pressure, temperature, concentration, and other relevant variables throughout the volume. This paper presents an overview of CFD study results from emergency ventilation analysis for a transit station and both emergency ventilation and diesel emissions analysis for a rail overbuild.

  2. The Imbalance of Water in Nature as System

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  3. [Home mechanical ventilation : Invasive and noninvasive ventilation therapy for chronic respiratory failure].

    PubMed

    Huttmann, S E; Storre, J H; Windisch, W

    2015-06-01

    Home mechanical ventilation represents a valuable therapeutic option to improve alveolar ventilation in patients with chronic respiratory failure. For this purpose both invasive ventilation via tracheostomy and noninvasive ventilation via facemasks are available. The primary goal of home mechanical ventilation is a reduction of symptoms, improvement of quality of life and in many cases reduction of mortality. Elective establishment of home mechanical ventilation is typically provided for noninvasive ventilation in respect to clinical symptoms and partial pressure of carbon dioxide depending on the underlying disease. However, invasive mechanical ventilation is increasingly being used to continue ventilatory support in polymorbid patients following unsuccessful weaning. Recommendations and guidelines have been published by the German Respiratory Society (DGP). PMID:26065554

  4. GPU-Accelerated Voxelwise Hepatic Perfusion Quantification

    PubMed Central

    Wang, H; Cao, Y

    2012-01-01

    Voxelwise quantification of hepatic perfusion parameters from dynamic contrast enhanced (DCE) imaging greatly contributes to assessment of liver function in response to radiation therapy. However, the efficiency of the estimation of hepatic perfusion parameters voxel-by-voxel in the whole liver using a dual-input single-compartment model requires substantial improvement for routine clinical applications. In this paper, we utilize the parallel computation power of a graphics processing unit (GPU) to accelerate the computation, while maintaining the same accuracy as the conventional method. Using CUDA-GPU, the hepatic perfusion computations over multiple voxels are run across the GPU blocks concurrently but independently. At each voxel, non-linear least squares fitting the time series of the liver DCE data to the compartmental model is distributed to multiple threads in a block, and the computations of different time points are performed simultaneously and synchronically. An efficient fast Fourier transform in a block is also developed for the convolution computation in the model. The GPU computations of the voxel-by-voxel hepatic perfusion images are compared with ones by the CPU using the simulated DCE data and the experimental DCE MR images from patients. The computation speed is improved by 30 times using a NVIDIA Tesla C2050 GPU compared to a 2.67 GHz Intel Xeon CPU processor. To obtain liver perfusion maps with 626400 voxels in a patient’s liver, it takes 0.9 min with the GPU-accelerated voxelwise computation, compared to 110 min with the CPU, while both methods result in perfusion parameters differences less than 10?6. The method will be useful for generating liver perfusion images in clinical settings. PMID:22892645

  5. GPU-accelerated voxelwise hepatic perfusion quantification

    NASA Astrophysics Data System (ADS)

    Wang, H.; Cao, Y.

    2012-09-01

    Voxelwise quantification of hepatic perfusion parameters from dynamic contrast enhanced (DCE) imaging greatly contributes to assessment of liver function in response to radiation therapy. However, the efficiency of the estimation of hepatic perfusion parameters voxel-by-voxel in the whole liver using a dual-input single-compartment model requires substantial improvement for routine clinical applications. In this paper, we utilize the parallel computation power of a graphics processing unit (GPU) to accelerate the computation, while maintaining the same accuracy as the conventional method. Using compute unified device architecture-GPU, the hepatic perfusion computations over multiple voxels are run across the GPU blocks concurrently but independently. At each voxel, nonlinear least-squares fitting the time series of the liver DCE data to the compartmental model is distributed to multiple threads in a block, and the computations of different time points are performed simultaneously and synchronically. An efficient fast Fourier transform in a block is also developed for the convolution computation in the model. The GPU computations of the voxel-by-voxel hepatic perfusion images are compared with ones by the CPU using the simulated DCE data and the experimental DCE MR images from patients. The computation speed is improved by 30 times using a NVIDIA Tesla C2050 GPU compared to a 2.67 GHz Intel Xeon CPU processor. To obtain liver perfusion maps with 626 400 voxels in a patient's liver, it takes 0.9 min with the GPU-accelerated voxelwise computation, compared to 110 min with the CPU, while both methods result in perfusion parameters differences less than 10-6. The method will be useful for generating liver perfusion images in clinical settings.

  6. A tuning fork gyroscope with compensated imbalance signal

    NASA Astrophysics Data System (ADS)

    Arnold, E.; Nuscheler, F.

    2007-05-01

    This paper is presenting a robust gyroscope sensor with an electrical and mechanical self-test option and the ability to suppress the quadrature error. The presented sensor is based on a tuning-fork working principle. The mechanical part is assembled in bulk-technology produced with a wet etching process. The two detection elements are manufactured with a standard CMOS-process and the material of the two thin-film actuators is AlN (aluminium-nitrid). The two actuators can be controlled independently from each other. Two electronic PCB's were developed for actuating and measurement. One is including the analogue signal path; the second PCB is the digital electronics consisting of a FPGA and other peripherals. The tuning fork is actuated in a primary oscillation mode also called drive mode. For keeping the oscillation in resonance, a digital PLL is used in a forced feedback loop. To have a constant energy in the drive mode an Amplitude-Gain-Control (AGC) is implemented. An appearing angular rate causes the corriolis-force which is actuating secondary oscillation, also called detection mode. The amplitude of this oscillation is proportional to the angular rate. The signal has a component resulting from the mechanical imbalance. To separate these two signal parts from each other a synchronous demodulator followed by a digital filter chain has been developed. To achieve the maximum suppression of the imbalance signal a control-loop is used to shift the phases of the two actuation signals. This creates an additional force that compensates the movement as a result of the mechanical imbalance. With the implementation of this control loop the performance of the sensor was increased. An enhanced temperature stability over operation was achieved with the means of this compensation.

  7. Injurious mechanical ventilation affects neuronal activation in ventilated rats

    Microsoft Academic Search

    Elisa María Quilez; Gemma Fuster; Jesús Villar; Carlos Flores; Octavi Martí-Sistac; Lluís Blanch; Josefina López-Aguilar

    2011-01-01

    Introduction  Survivors of critical illness often have significant long-term brain dysfunction, and routine clinical procedures like mechanical\\u000a ventilation (MV) may affect long-term brain outcome. We aimed to investigate the effect of the increase of tidal volume (Vt)\\u000a on brain activation in a rat model.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Male Sprague Dawley rats were randomized to three groups: 1) Basal: anesthetized unventilated animals, 2) low Vt

  8. Neurally adjusted ventilatory assist: a ventilation tool or a ventilation toy?

    PubMed

    Verbrugghe, Walter; Jorens, Philippe G

    2011-03-01

    Mechanical ventilation has, since its introduction into clinical practice, undergone a major evolution from controlled ventilation to various modes of assisted ventilation. Neurally adjusted ventilatory assist (NAVA) is the newest development. The implementation of NAVA requires the introduction of a catheter to measure the electrical activity of the diaphragm (EA(di)). NAVA relies, opposite to conventional assisted ventilation modes, on the EA(di) to trigger the ventilator breath and to adjust the ventilatory assist to the neural drive. The amplitude of the ventilator assist is determined by the instantaneous EA(di) and the NAVA level set by the clinician. The NAVA level amplifies the EA(di) signal and determines instantaneous ventilator assist on a breath-to-breath basis. Experimental and clinical data suggest superior patient-ventilator synchrony with NAVA. Patient-ventilator asynchrony is present in 25% of mechanically ventilated patients in the intensive care unit and may contribute to patient discomfort, sleep fragmentation, higher use of sedation, development of delirium, ventilator-induced lung injury, prolonged mechanical ventilation, and ultimately mortality. With NAVA, the reliance on the EA(di) signal, together with an intact ventilatory drive and intact breathing reflexes, allows integration of the ventilator in the neuro-ventilatory coupling on a higher level than conventional ventilation modes. The simple monitoring of the EA(di) signal alone may provide the clinician with important information to guide ventilator management, especially during the weaning process. Although, until now, little evidence proves the superiority of NAVA on clinically relevant end points, it seems evident that patient populations (eg, COPD and small children) with major patient-ventilator asynchrony may benefit from this new ventilatory tool. PMID:21255496

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

    PubMed Central

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

    2013-01-01

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

  10. Ventilator-induced respiratory muscle weakness

    PubMed Central

    Tobin, Martin J.; Laghi, Franco; Jubran, Amal

    2010-01-01

    Clinicians have long been aware that substantial lung injury results when mechanical ventilation imposes too much stress on the pulmonary parenchyma. Evidence is accruing that substantial injury may also result when the ventilator imposes too little stress on the respiratory muscles. Through adjustment of ventilator settings and administration of pharmacotherapy it is possible to render the respiratory muscles almost (or completely) inactive. Research in animals has shown that diaphragmatic inactivity produces severe injury and atrophy of muscle fibers. Human data have recently revealed that 18 to 69 hours of complete diaphragmatic inactivity associated with mechanical ventilation decreased the cross-sectional areas of diaphragmatic fibers by half or more. The atrophic injury appears to result from increased oxidative stress leading to activation of protein-degradation pathways. Scientific understanding of ventilator-induced respiratory muscle injury has not reached the stage where it is possible to undertake meaningful controlled trials and thus it is not possible to render concrete recommendations for patient management. In the meantime, clinicians are advised to select ventilator settings that avoid both excessive patient effort and also excessive respiratory muscle rest. The contour of the airway pressure waveform on a ventilator screen provides the most practical indication of patient effort, and clinicians are advised to pay close attention to the waveform as they titrate ventilator settings. Research on ventilator-induced respiratory muscle injury is in its infancy and portends to be an exciting area to follow. PMID:20713792

  11. Quantitative assessment of acute kidney injury by noninvasive arterial spin labeling perfusion MRI: a pilot study.

    PubMed

    Dong, Jian; Yang, Li; Su, Tao; Yang, XueDong; Chen, Bin; Zhang, Jue; Wang, XiaoYing; Jiang, XueXiang

    2013-08-01

    The kidneys are essential for maintaining homeostasis, are responsible for the reabsorption of water, glucose and amino acids, and filter the blood by removing waste. Acute kidney injury (AKI) is a syndrome characterized by the rapid loss of renal excretory function and the accumulation of end metabolic products of urea and creatinine. AKI is associated with the later development of chronic kidney disease and end-stage kidney disease, and may eventually be fatal. Early diagnosis of AKI and assessments of the effects of treatment, however, are challenging. The pathophysiological mechanism of AKI is thought to be the imbalance between oxygen supply and demand in the kidneys. We have assessed the ability of arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI), without the administration of contrast media, to quantify renal blood flow (RBF) non-invasively. We found that RBF was significantly lower in AKI patients than in healthy volunteers. These results suggest that ASL perfusion MRI, a noninvasive measurement of RBF, may be useful in the early diagnosis of AKI. PMID:23740361

  12. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED...and Equipment Cargo Handling Space Ventilation § 153.312 ...standards. A cargo handling space ventilation system must meet...for, accommodation or service spaces. (b) A ventilation...

  13. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED...and Equipment Cargo Handling Space Ventilation § 153.312 ...standards. A cargo handling space ventilation system must meet...for, accommodation or service spaces. (b) A ventilation...

  14. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED...and Equipment Cargo Handling Space Ventilation § 153.312 ...standards. A cargo handling space ventilation system must meet...for, accommodation or service spaces. (b) A ventilation...

  15. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED...and Equipment Cargo Handling Space Ventilation § 153.312 ...standards. A cargo handling space ventilation system must meet...for, accommodation or service spaces. (b) A ventilation...

  16. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED...and Equipment Cargo Handling Space Ventilation § 153.312 ...standards. A cargo handling space ventilation system must meet...for, accommodation or service spaces. (b) A ventilation...

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

    PubMed

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

    2014-08-01

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

  18. The measurement of effort–reward imbalance at work: European comparisons

    Microsoft Academic Search

    Johannes Siegrist; Dagmar Starke; Tarani Chandola; Isabelle Godin; Michael Marmot; Isabelle Niedhammer; Richard Peter

    2004-01-01

    Using comparative data from five countries, this study investigates the psychometric properties of the effort–reward imbalance (ERI) at work model. In this model, chronic work-related stress is identified as non-reciprocity or imbalance between high efforts spent and low rewards received. Health-adverse effects of this imbalance were documented in several prospective and cross-sectional investigations. The internal consistency, discriminant validity and factorial

  19. 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

  20. Optical Perfusion and Oxygenation Characterization in a Liver Phantom

    E-print Network

    King, Travis J.

    2012-02-14

    Continuous monitoring of blood perfusion and oxygenation is essential in assessing the health of a transplanted organ. Particularly, monitoring the perfusion and oxygenation of the organ during the two-week period after the transplant procedure...

  1. Perfusion lung imaging in the adult respiratory distress syndrome

    SciTech Connect

    Pistolesi, M.; Miniati, M.; Di Ricco, G.; Marini, C.; Giuntini, C.

    1986-07-01

    In 29 perfusion lung scans (PLS) of 19 patients with ARDS, 20 of which were obtained within six days from the onset of respiratory symptoms, perfusion abnormalities were the rule. These included focal, nonsegmental defects, mostly peripheral and dorsal, and perfusion redistribution away from the dependent lung zones. PLS were scored for the presence and intensity of perfusion abnormalities and the scores of perfusion redistribution were validated against numerical indices of blood flow distribution per unit lung volume. PLS scores were correlated with arterial blood gas values, hemodynamic parameters, and chest radiographic scores of ARDS. Arterial oxygen tension correlated with the scores of both perfusion defects and redistribution. Perfusion defects correlated better with the radiographic score of ARDS, and perfusion redistribution with PAP and vascular resistance. ARDS patients exhibit peculiar patterns of PLS abnormalities not observed in other disorders. Thus, PLS may help considerably in the detection and evaluation of pulmonary vascular injury in ARDS.

  2. A novel microthermal probe for the measurement of perfusion

    NASA Astrophysics Data System (ADS)

    Yi, Ming; Kausik, Aditya; Podhajsky, Ronald J.; Mahajan, Roop L.

    2009-02-01

    Using micro-fabrication techniques a micro thermal probe has been developed in our laboratory to measure the thermal conductivity of biological tissues. This paper presents our latest experimental results which demonstrate the usefulness of the micro thermal probe in mapping the complicated perfusion field inside biological tissues. A perfused pig liver model has been constructed to simulate in vivo conditions. The portal vein and hepatic artery of a porcine liver were intubated and connected to a perfusion circuit. Saline water was perfused through the liver driven by a peristaltic pump. By varying the pumping rate of the perfused model, we measured the effective thermal conductivity at different perfusion rates in different locations. The results show that the effective thermal conductivity varies with the square root of the perfusion rate. Also, by rotating the micro probes, we observed a strong directional dependence of the effective thermal conductivity, revealing that perfusion is not a scalar but a vector field.

  3. Detecting changes in serial myocardial perfusion SPECT: A simulation study

    E-print Network

    Modersitzki, Jan

    photon emission computed tomography (SPECT). Methods and Results. We generated 72 simulations: Single photon emission computed tomography · t values · myocardial perfusion Comparisons of visual perfusion images improves not only over- all diagnostic accuracy but also enhances reliability, confidence

  4. 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

  5. Penumbral imaging by using perfusion computed tomography and perfusion-weighted magnetic resonance imaging: current concepts.

    PubMed

    Sasaki, Makoto; Kudo, Kohsuke; Christensen, Soren; Yamashita, Fumio; Goodwin, Jonathan; Higuchi, Satomi; Ogawa, Akira

    2013-11-01

    Perfusion computed tomography and perfusion-weighted magnetic resonance imaging are used to evaluate the extent of the area with ischemic penumbra; however, different parameters, algorithms, and software packages show significant discrepancies in the size of perfusion abnormalities, which should be minimized. Recently, cross-validation studies were performed using digital phantoms and have elucidated the precision and reliability of various penumbral imaging techniques. These research initiatives can promote further multicenter trials on recanalization therapies by providing accurate inclusion/exclusion criteria for appropriate patient selection. PMID:23153549

  6. Insufficient unilateral cerebral perfusion during emergent aortic arch surgery

    PubMed Central

    Urbanski, Paul P.; Babin-Ebell, Jörg; Fröhner, Steffen; Diegeler, Anno

    2012-01-01

    A rare case of insufficient right-sided unilateral cerebral perfusion during emergent aortic arch replacement in a patient with an acute aortic dissection is reported. On the basis of intraoperative monitoring using near-infrared spectroscopy, the insufficient perfusion of the contralateral hemisphere was detected and the bilateral perfusion was performed, which led to normalization of cerebral perfusion and an uncomplicated neurological outcome. PMID:22108941

  7. YMP Engineered Barrier Systems Scaled Ventilation Testing

    SciTech Connect

    S.D. Dunn; B. Lowry; B. Walsh; J.D. Mar; C. Howard; R. Johnston; T. Williams

    2002-11-22

    Yucca Mountain, approximately 100 miles northwest of Las Vegas, Nevada, has been selected as the site for the nation's first geologic repository for high level nuclear waste. The Yucca Mountain Project (YMP) is currently developing the design for the underground facilities. Ventilation is a key component of the design as a way to maintain the desired thermal conditions in the emplacement drifts prior to closure. As a means of determining the effects of continuous ventilation on heat removal from the emplacement drifts two series of scaled ventilation tests have been performed. Both test series were performed in the DOE/North Las Vegas Atlas facility. The tests provided scaled (nominally 25% of the full scale emplacement drift design) thermal and flow process data that will be used to validate YMP heat and mass transport codes. The Phase I Ventilation Test series evaluated the ability of ambient ventilation air to remove energy under varying flow and input power conditions. The Phase II Ventilation Test series evaluated the ability of pre-conditioned ventilation air to remove energy under varying flow, input temperature and moisture content, and simulated waste package input power conditions. Twenty-two distinct ventilation tests were run.

  8. 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.

  9. Microprocessor control of broiler house ventilation

    SciTech Connect

    Kay, F.W.; Allison, J.M.

    1983-06-01

    An M6800 microprocessor control system for ventilation fans, supplemental heaters, and air inlet slots is presented. The control system uses inputs from temperature sensors, both inside and outside the house, along with the desired environmental conditions inside to calculate the required ventilation for heat and moisture control.

  10. Transpleural ventilation of explanted human lungs

    Microsoft Academic Search

    Cliff K Choong; Peter T Macklem; John A Pierce; Stephen S Lefrak; Jason C Woods; Mark S Conradi; Dimitry A Yablonskiy; James C Hogg; Kimiaki Chino; Joel D Cooper

    2007-01-01

    Background: The hypothesis that ventilation of emphysematous lungs would be enhanced by communication with the parenchyma through holes in the pleural surface was tested.Methods: Fresh human lungs were obtained from patients with emphysema undergoing lung transplantation. Control human lungs were obtained from organ donors whose lungs, for technical reasons, were not considered suitable for implantation. Lungs were ventilated through the

  11. Face ventilation for oil shale mining

    Microsoft Academic Search

    E. D. Thimons; C. E. Brechtel; M. E. Adam; J. F. T. Agapito

    1986-01-01

    This Bureau of Mines report presents expected levels of air pollutants in the face ares of oil shale mines, based upon data collected by the authors and previous investigators. Ventilation requirements to maintain these pollutant levels below their threshold limit values and Federal and local mine air quality standards are discussed. Two practical face ventilation systems are discussed in terms

  12. The interface: crucial for successful noninvasive ventilation

    Microsoft Academic Search

    M. W. Elliott

    2004-01-01

    Noninvasive ventilation (NIV) is a real advance in the management of both chronic and acute respiratory failure. It is the absence of an endotracheal or tracheostomy tube which defines NIV. The development of various interfaces have made the delivery of effective ventilation to patients without intubation possible and a good interface is crucial to success. These can be factory manufactured

  13. 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

  14. Long-term mechanical ventilation: management strategies.

    PubMed

    White, Alexander C

    2012-06-01

    This paper reviews management strategies for patients undergoing prolonged mechanical ventilation (PMV). Topics covered include how to identify and correct barriers to weaning, the systematic approach to weaning trials, when to cease weaning trials and proceed with life-long support, managing the tracheostomy tube during PMV, and, finally, how to select a suitable mechanical ventilator for PMV. PMID:22663965

  15. Noninvasive Ventilation for Acute Respiratory Failure

    Microsoft Academic Search

    L. Brochard; J. Mancebo; M. W. Elliott

    2002-01-01

    Noninvasive ventilation for acute respiratory failure. L. Brochard, J. Mancebo, M.W. Elliott. #ERS Journals Ltd 2002. ABSTRACT: Noninvasive ventilation (NIV) has emerged as a significant advance in the management of respiratory failure. There is now a wide body of prospective randomized-controlled trial data to support its use, particularly in the management of patients with acute or respiratory failure due to

  16. 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.

  17. 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

  18. Increased sinusoidal volume and solute extraction during retrograde liver perfusion

    SciTech Connect

    Bass, N.M.; Manning, J.A.; Weisiger, R.A.

    1989-06-01

    Retrograde isolated liver perfusion has been used to probe acinar functional heterogeneity, but the hemodynamic effects of backward flow have not been characterized. In this study, extraction of a long-chain fatty acid derivative, 12-N-methyl-7-nitrobenzo-2-oxa-1,3-diazol-amino stearate (12-NBDS), was greater during retrograde than during anterograde perfusion of isolated rat liver. To determine whether hemodynamic differences between anterograde and retrograde perfused livers could account for this finding, the hepatic extracellular space was measured for both directions of flow by means of (/sup 14/C)sucrose washout during perfusion as well as by direct measurement of (/sup 14/C)sucrose entrapped during perfusion. A three- to fourfold enlargement of the total hepatic extracellular space was found during retrograde perfusion by both approaches. Examination of perfusion-fixed livers by light microscopy and morphometry revealed that marked distension of the sinusoids occurred during retrograde perfusion and that this accounts for the observed increase in the (/sup 14/C)sucrose space. These findings support the hypothesis that maximum resistance to perfusate flow in the isolated perfused rat liver is located at the presinusoidal level. In addition, increased transit time of perfusate through the liver and greater sinusoidal surface area resulting from sinusoidal distension may account for the higher extraction of 12-NBDS and possibly other compounds by retrograde perfused liver.

  19. A laser speckle imaging technique for measuring tissue perfusion

    Microsoft Academic Search

    Kevin R. Forrester; J. Tulip; C. Leonard; C. Stewart; Robert C. Bray

    2004-01-01

    Laser Doppler imaging (LDI) has become a standard method for optical measurement of tissue perfusion, but is limited by low resolution and long measurement times. We have developed an analysis technique based on a laser speckle imaging method that generates rapid, high-resolution perfusion images. We have called it laser speckle perfusion imaging (LSPI). This paper investigates LSPI output and compares

  20. 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.

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

    PubMed

    Pikwer, Andreas

    2011-10-01

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

  2. 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.

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

    PubMed Central

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

    2015-01-01

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

  4. Simplified prototyping of perfusable polystyrene microfluidics.

    PubMed

    Tran, Reginald; Ahn, Byungwook; R Myers, David; Qiu, Yongzhi; Sakurai, Yumiko; Moot, Robert; Mihevc, Emma; Trent Spencer, H; Doering, Christopher; A Lam, Wilbur

    2014-07-01

    Cell culture in microfluidic systems has primarily been conducted in devices comprised of polydimethylsiloxane (PDMS) or other elastomers. As polystyrene (PS) is the most characterized and commonly used substrate material for cell culture, microfluidic cell culture would ideally be conducted in PS-based microsystems that also enable tight control of perfusion and hydrodynamic conditions, which are especially important for culture of vascular cell types. Here, we report a simple method to prototype perfusable PS microfluidics for endothelial cell culture under flow that can be fabricated using standard lithography and wet laboratory equipment to enable stable perfusion at shear stresses up to 300?dyn/cm(2) and pumping pressures up to 26?kPa for at least 100 h. This technique can also be extended to fabricate perfusable hybrid PS-PDMS microfluidics of which one application is for increased efficiency of viral transduction in non-adherent suspension cells by leveraging the high surface area to volume ratio of microfluidics and adhesion molecules that are optimized for PS substrates. These biologically compatible microfluidic devices can be made more accessible to biological-based laboratories through the outsourcing of lithography to various available microfluidic foundries. PMID:25379106

  5. Infrared facial recognition using modified blood perfusion

    Microsoft Academic Search

    Shiqian Wu; Zhenghui Gu; Kia Ai Chia; Sim Heng Ong

    2007-01-01

    An infrared (IR) facial image represents a measurement of thermal distribution of a face which is independent of illumination. However, it has been found that facial thermograms vary with ambient temperature, physiological as well as psychological conditions, which result in severe decline in recognition rate. In this paper, we present a modified blood perfusion model which is much simpler than

  6. 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.

  7. A reappraisal of retrograde cerebral perfusion

    PubMed Central

    2013-01-01

    Brain protection during aortic arch surgery by perfusing cold oxygenated blood into the superior vena cava was first reported by Lemole et al. In 1990 Ueda and associates first described the routine use of continuous retrograde cerebral perfusion (RCP) in thoracic aortic surgery for the purpose of cerebral protection during the interval of obligatory interruption of anterograde cerebral flow. The beneficial effects of RCP may be its ability to sustain brain hypothermia during hypothermic circulatory arrest (HCA) and removal of embolic material from the arterial circulation of the brain. RCP can offer effective brain protection during HCA for about 40 to 60 minutes. Animal experiments revealed that RCP provided inadequate cerebral perfusion and that neurological recovery was improved with selective antegrade cerebral perfusion (ACP), however, both RCP and ACP provide comparable clinical outcomes regarding both the mortality and stroke rates by risk-adjusted and case-matched comparative study. RCP still remains a valuable adjunct for brain protection during aortic arch repair in particular pathologies and patients. PMID:23977600

  8. Reduced frontotemporal perfusion in psychopathic personality

    Microsoft Academic Search

    Henrik Soderstrom; Leif Hultin; Mats Tullberg; Carsten Wikkelso; Sven Ekholm; Anders Forsman

    2002-01-01

    Several brain-imaging studies have found associations between aberrant functioning in the frontal and temporal lobes and violent offending. We have previously reported decreased frontotemporal perfusion unrelated to psychosis, substance abuse, or current medication in 21 violent offenders. In the present study, we compared the regional cerebral blood flow (rCBF) in a new group of 32 violent offenders to scores on

  9. Ventilator for internal combustion engine

    SciTech Connect

    Aoki, K.

    1986-04-08

    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 acting to open or close an opening at an upper end of the outlet tube for controlling the quantity of blowby gas introduced into the outlet tube from the pressure chamber; an oil sump located at a lower end of the outlet tube and having a given capacity; a check valve mounted at the bottom of the oil sump to allow fluid to flow from the sump toward the pressure chamber; and an outlet port formed through the side wall of the outlet tube and protruding radially outwardly, the outlet tube being in communication with the intake manifold via the outlet port.

  10. Class Imbalances versus Class Overlapping: An Analysis of a Learning System Behavior

    Microsoft Academic Search

    Ronaldo C. Prati; Gustavo E. A. P. A. Batista; Maria Carolina Monard

    2004-01-01

    Several works point out class imbalance as an obstacle on applying machine learning algorithms to real world domains. However, in some cases, learning algorithms perform well on several imbalanced domains. Thus, it does not seem fair to directly correlate class imbalance to the loss of performance of learning algorithms. In this work, we develop a systematic study aiming to question

  11. Detection of mechanical imbalances of induction machines without spectral analysis of time-domain signals

    Microsoft Academic Search

    Christian Kral; Thomas G. Habetler; Ronald G. Harley

    2004-01-01

    Mechanical rotor imbalances and rotor eccentricities are reflected in electric, electromagnetic, and mechanical quantities. Therefore, many surveillance schemes determine the Fourier spectrum of a single line current in order to monitor the motor condition. Mechanical imbalances give rise to two first-order current harmonics. Due to the interaction of the currents and voltages, both these current harmonics are also reflected by

  12. A dynamical investigation of the heat and helium imbalance Peter E. van Keken aY

    E-print Network

    van Keken, Peter

    and helium released from the whole mantle convection models is smaller than the production ratioA dynamical investigation of the heat and helium imbalance Peter E. van Keken aY *, Chris J; accepted 6 April 2001 Abstract The terrestrial heat^helium imbalance [O'Nions and Oxburgh, Nature 306 (1983

  13. A comparison between the effort-reward imbalance and demand control models

    PubMed Central

    Ostry, Aleck S; Kelly, Shona; Demers, Paul A; Mustard, Cameron; Hertzman, Clyde

    2003-01-01

    Background To compare the predictive validity of the demand/control and reward/imbalance models, alone and in combination with each other, for self-reported health status and the self-reported presence of any chronic disease condition. Methods Self-reports for psychosocial work conditions were obtained in a sample of sawmill workers using the demand/control and effort/reward imbalance models. The relative predictive validity of task-level control was compared with effort/reward imbalance. As well, the predictive validity of a model developed by combining task-level control with effort/reward imbalance was determined. Logistic regression was utilized for all models. Results The demand/control and effort/reward imbalance models independently predicted poor self-reported health status. The effort-reward imbalance model predicted the presence of a chronic disease while the demand/control model did not. A model combining effort-reward imbalance and task-level control was a better predictor of self-reported health status and any chronic condition than either model alone. Effort reward imbalance modeled with intrinsic effort had marginally better predictive validity than when modeled with extrinsic effort only. Conclusions Future work should explore the combined effects of these two models of psychosocial stress at work on health more thoroughly. PMID:12636876

  14. Home mechanical ventilation. Demographics and user perspectives.

    PubMed

    Goldstein, R S; Psek, J A; Gort, E H

    1995-12-01

    Although the number of users of home mechanical ventilation (HMV) is increasing, information regarding the users' perceptions of the impact of HMV on their lives is incomplete. We administered an open-ended questionnaire to 98 (48 male, 50 female) HMV users aged (mean +/- SD) 47.4 +/- 19.5 years with COPD (9%), thoracic restrictive disease (43%), and neuromuscular disease (48%). At the time of survey, subjects had received HMV for 59.5 +/- 58.3 months. Fifty-three percent were ventilated electively. Ventilator use was continuous (18%), at night only (37%), or at night with occasional daytime use (45%). Twenty-seven (28%) individuals identified themselves as being totally independent while 32 (33%) rated themselves as partially dependent on caregiver assistance for daily activities. Only 37 (38%) considered that they had made an informed choice when first starting HMV whereas 54 (55%) did not. The impact of using a mechanical ventilator was believed to be overwhelmingly positive (87%). Positive comments regarding the impact of the ventilator on lifestyle were grouped in the following categories: life sustaining, facilitating mobility, and improving physical symptoms. Negative comments were grouped in the following categories: limiting mobility, equipment issues, and social implications. HMV users with a tracheostomy volunteered significantly fewer positive statements than those ventilated noninvasively (p < 0.05). Whereas 52 (53%) of users indicated that they had experienced initial difficulties in coping with the ventilator, only 11 (11%) identified difficulties at the time of the survey. PMID:7497765

  15. 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.

  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. 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

  18. Cardiopulmonary resuscitation among mechanically ventilated patients

    PubMed Central

    Al-Alwan, Ali; Ehlenbach, William J.; Menon, Prema R.; Young, Michael P.; Stapleton, Renee D.

    2014-01-01

    Purpose To evaluate the outcomes, including long term survival, after CPR in mechanically ventilated patients. Methods We analyzed Medicare data from 1994-2005 to identify beneficiaries who underwent in-hospital CPR. We then identified a subgroup receiving CPR one or more days after mechanical ventilation was initiated (defined by ICD-9 procedure code for intubation [96.04] or mechanical ventilation [96.7x] one or more days prior to procedure code for CPR [99.60 or 99.63]). Results We identified 471,962 patients who received in-hospital CPR with an overall survival to hospital discharge of 18.4% (95% confidence interval [CI] 18.3-18.5%). Of those, 42,163 received CPR one or more days after mechanical ventilation initiation. Survival to hospital discharge after CPR in ventilated patients was 10.1% (95% CI 9.8%-10.4%), compared to 19.2% (95% CI 19.1%-19.3%) in non-ventilated patients (p<0.001). Among this group, older age, race other than white, higher burden of chronic illness, and admission from a nursing facility were associated with decreased survival in multivariable analyses. Among all CPR recipients, those who were ventilated had 52% lower odds of survival (OR 0.48, 95% CI 0.46-0.49, p<0.001). Median long term survival in ventilated patients receiving CPR who survived to hospital discharge was 6.0 months (95% CI 5.3-6.8 months), compared to 19.0 months (95% CI 18.6-19.5 months) among the non-ventilated survivors (p=<0.001 by logrank test). Of all patients receiving CPR while ventilated, only 4.1% were alive at one year. Conclusions Survival after in-hospital CPR is decreased among ventilated patients compared to those who are not ventilated. This information is important for clinicians, patients, and family members when discussing CPR in critically ill patients. PMID:24570267

  19. 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

  20. 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.

  1. Noninvasive Ventilation in Critically Ill Patients.

    PubMed

    Gregoretti, Cesare; Pisani, Lara; Cortegiani, Andrea; Ranieri, Vito Marco

    2015-07-01

    Since its first application in the late 1980s, noninvasive ventilation (NIV) has been the first-line intervention for certain forms of acute respiratory failure. NIV may be delivered through the patient's mouth, nose, or both using noninvasive intermittent positive pressure ventilation or continuous positive airway pressure. When applied appropriately, NIV may reduce morbidity and mortality and may avert iatrogenic complications and infections associated with invasive mechanical ventilation. This article provides physicians and respiratory therapists with a comprehensive, practical guideline for using NIV in critical care. PMID:26118914

  2. Application of Information Technology: Enhanced Notification of Critical Ventilator Events

    Microsoft Academic Search

    R. Scott Evans; Kyle V. Johnson; Vrena B. Flint; Tupper Kinder; Charles R. Lyon; William L. Hawley; David K. Vawdrey; George E. Thomsen

    2005-01-01

    Mechanical ventilators are designed to generate alarms when patients become disconnected or experience other critical ventilator events. However, these alarms can blend in with other accustomed sounds of the intensive care unit. Ventilator alarms that go unnoticed for extended periods of time often result in permanent patient harm or death. We developed a system to monitor critical ventilator events through

  3. Comparison of two ventilation modes in post-cardiac surgical patients

    PubMed Central

    Samantaray, Aloka; Hemanth, Nathan

    2011-01-01

    Background: The cardiopulmonary bypass (CPB)-associated atelectasis accounted for most of the marked post-CPB increase in shunt and hypoxemia. We hypothesized that pressure-regulated volume-control (PRVC) modes having a distinct theoretical advantage over pressure-controlled ventilation (PCV) by providing the target tidal volume at the minimum available pressure may prove advantageous while ventilating these atelactic lungs. Methods: In this prospective study, 36 post-cardiac surgical patients with a PaO2/FiO2 (arterial oxygen tension/Fractional inspired oxygen) < 300 after arrival to intensive care unit (ICU), (n = 34) were randomized to receive either PRVC or PCV. Air way pressure (Paw) and arterial blood gases (ABG) were measured at four time points [T1: After induction of anesthesia, T2: after CPB (in the ICU), T3: 1 h after intervention mode, T4: 1 h after T3]. Oxygenation index (OI) = [PaO2/ {FiO2 × mean airway pressure (Pmean)}] was calculated for each set of data and used as an indirect estimation for intrapulmonary shunt. Results: There is a steady and significant improvement in OI in both the groups at first hour [PCV, 27.5(3.6) to 43.0(7.5); PRVC, 26.7(2.8) to 47.6(8.2) (P = 0.001)] and second hour [PCV, 53.8(6.4); PRVC, 65.8(7.4) (P = 0.001)] of ventilation. However, the improvement in OI was more marked in PRVC at second hour of ventilation owing to significant low mean air way pressure compared to the PCV group [PCV, 8.6(0.8); PRVC, 7.7(0.5), P = 0.001]. Conclusions: PRVC may be useful in a certain group of patients to reduce intrapulmonary shunt and improve oxygenation after cardiopulmonary bypass-induced perfusion mismatch. PMID:21804799

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

    PubMed

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

    2015-07-01

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

  5. 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

  6. MR-compatible ventilator for small animals: computer-controlled ventilation for proton and noble gas imaging

    E-print Network

    For magnetic resonance imaging (MRI) of small animals, mechanical ventilation is often necessary to maintain valves. These breathing valves attach directly to the animal's en- trotracheal tube to minimize ventilMR-compatible ventilator for small animals: computer-controlled ventilation for proton and noble

  7. Performance Assessment of Photovoltaic Attic Ventilator Fans 

    E-print Network

    Parker, D. S.; Sherwin, J. R.

    2000-01-01

    has long been identified as a method to abate such heat gains. We present test results from using the photovoltaic (PV) attic ventilator fans in a test home to assess impact on attic and cooling energy performance....

  8. 21 CFR 868.5895 - Continuous ventilator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...mechanically control or assist patient breathing by delivering a predetermined percentage of oxygen in the breathing gas. Adult, pediatric, and neonatal ventilators are included in this generic type of device. (b) Classification. Class II...

  9. 21 CFR 868.5895 - Continuous ventilator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...mechanically control or assist patient breathing by delivering a predetermined percentage of oxygen in the breathing gas. Adult, pediatric, and neonatal ventilators are included in this generic type of device. (b) Classification. Class II...

  10. 21 CFR 868.5895 - Continuous ventilator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...mechanically control or assist patient breathing by delivering a predetermined percentage of oxygen in the breathing gas. Adult, pediatric, and neonatal ventilators are included in this generic type of device. (b) Classification. Class II...

  11. 21 CFR 868.5895 - Continuous ventilator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...mechanically control or assist patient breathing by delivering a predetermined percentage of oxygen in the breathing gas. Adult, pediatric, and neonatal ventilators are included in this generic type of device. (b) Classification. Class II...

  12. 21 CFR 868.5895 - Continuous ventilator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...mechanically control or assist patient breathing by delivering a predetermined percentage of oxygen in the breathing gas. Adult, pediatric, and neonatal ventilators are included in this generic type of device. (b) Classification. Class II...

  13. Waste tank ventilation system waste material accumulations

    SciTech Connect

    Van Vleet, R.J., Westinghouse Hanford

    1996-08-06

    This paper calculates the amount of material that accumulates in the ventilation systems of various Tank Waste Remediation System facilities and estimates the amount of material that could be released due to a rapid pressurization.

  14. Scale model studies of displacement ventilation

    E-print Network

    Okutan, Galip Mehmet

    1995-01-01

    Displacement ventilation is an air conditioning method that provides conditioned air to indoor environments with the goal to improve air quality while reducing energy consumption. This study investigates the performance ...

  15. Speech for People with Tracheostomies or Ventilators

    MedlinePLUS

    Speech for People With Tracheostomies or Ventilators [ en Español ] What is a tracheostomy ? What happens when a ... choking. What impact does a tracheostomy have on speech? People who have a tracheostomy cannot speak in ...

  16. Analysis to ventilation effectiveness in subway fire environment

    Microsoft Academic Search

    Wen-Zhong Wu; Shi-Jun You

    2009-01-01

    When longitudinal ventilation is activated in subway station platform fire, smoke-control effectiveness depends on ventilation effectiveness. With the ventilation motion analyzed, its time at staircase is decreased and ventilation effectiveness gets better all along platform. In case of 30 MW fire with 80 m3\\/s smoke volume flow rate, longitudinal ventilation of bigger than 1.5 m\\/s freshens platform all around for

  17. 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.

  18. Long-term mechanical ventilation and nutrition

    Microsoft Academic Search

    Nicolino Ambrosino; Enrico Clini

    2004-01-01

    Mechanical ventilation (MV) in chronic situations is commonly used, either delivered invasively or by means of non-invasive interfaces, to control hypoventilation in patients with chest wall, neuromuscular or obstructive lung diseases (either in adulthood or childhood). The global prevalence of ventilator-assisted individuals (VAI) in Europe ranges from 2 to 30 per 100000 population according to different countries.Nutrition is a common

  19. Invasive Ventilation and Acute Heart Failure Syndrome

    Microsoft Academic Search

    Jean-Damien Ricard; Damien Roux

    Because utilization of noninvasive ventilatory techniques considerably reduces the need for endotracheal intubation and invasive\\u000a mechanical ventilation during acute heart failure syndrome (AHFS) (1, 2), the recent guidelines issued by the European Society of Cardiology (3) recommend that invasive mechanical ventilation in the setting of acute heart failure (AHF) should be considered only after\\u000a failure of noninvasive methods, such as

  20. Ventilation measurements in large office buildings

    Microsoft Academic Search

    A. K. Persily; R. A. Grot

    1985-01-01

    Ventilation rates were measured in nine office buildings using an automated tracer gas measuring system. The buildings range in size from a two-story federal building with a floor area of about 20,000 ft² (1900 m²) to a 26-story office building with a floor area of 700,000 ft² (65,000 m²). The ventilation rates were measured for about 100 hours in each

  1. Perioperative lung protective ventilation in obese patients.

    PubMed

    Fernandez-Bustamante, Ana; Hashimoto, Soshi; Serpa Neto, Ary; Moine, Pierre; Vidal Melo, Marcos F; Repine, John E

    2015-01-01

    The perioperative use and relevance of protective ventilation in surgical patients is being increasingly recognized. Obesity poses particular challenges to adequate mechanical ventilation in addition to surgical constraints, primarily by restricted lung mechanics due to excessive adiposity, frequent respiratory comorbidities (i.e. sleep apnea, asthma), and concerns of postoperative respiratory depression and other pulmonary complications. The number of surgical patients with obesity is increasing, and facing these challenges is common in the operating rooms and critical care units worldwide. In this review we summarize the existing literature which supports the following recommendations for the perioperative ventilation in obese patients: (1) the use of protective ventilation with low tidal volumes (approximately 8 mL/kg, calculated based on predicted -not actual- body weight) to avoid volutrauma; (2) a focus on lung recruitment by utilizing PEEP (8-15 cmH2O) in addition to recruitment maneuvers during the intraoperative period, as well as incentivized deep breathing and noninvasive ventilation early in the postoperative period, to avoid atelectasis, hypoxemia and atelectrauma; and (3) a judicious oxygen use (ideally less than 0.8) to avoid hypoxemia but also possible reabsorption atelectasis. Obesity poses an additional challenge for achieving adequate protective ventilation during one-lung ventilation, but different lung isolation techniques have been adequately performed in obese patients by experienced providers. Postoperative efforts should be directed to avoid hypoventilation, atelectasis and hypoxemia. Further studies are needed to better define optimum protective ventilation strategies and analyze their impact on the perioperative outcomes of surgical patients with obesity. PMID:25907273

  2. Transpleural ventilation of explanted human lungs

    PubMed Central

    Choong, Cliff K; Macklem, Peter T; Pierce, John A; Lefrak, Stephen S; Woods, Jason C; Conradi, Mark S; Yablonskiy, Dimitry A; Hogg, James C; Chino, Kimiaki; Cooper, Joel D

    2007-01-01

    Background The hypothesis that ventilation of emphysematous lungs would be enhanced by communication with the parenchyma through holes in the pleural surface was tested. Methods Fresh human lungs were obtained from patients with emphysema undergoing lung transplantation. Control human lungs were obtained from organ donors whose lungs, for technical reasons, were not considered suitable for implantation. Lungs were ventilated through the bronchial tree or transpleurally via a small hole communicating with the underlying parenchyma over which a flanged silicone tube had been cemented to the surface of the lung (spiracle). Measurements included flow?volume?time curves during passive deflation via each pathway; volume of trapped gas recovered from lungs via spiracles when no additional gas was obtainable passively from the airways; and magnetic resonance imaging assessment of spatial distribution of hyperpolarised helium (3He) administered through either the airways or spiracles. Results In emphysematous lungs, passively expelled volumes at 20?s were 94% greater through spiracles than via the airways. Following passive deflation from the airways, an average of 1.07?litres of trapped gas volume was recoverable via spiracles. Regions were ventilated by spiracles that were less well ventilated via bronchi. Conclusions Because of the extensive collateral ventilation present in emphysematous lungs, direct communication with the lung parenchyma through non?anatomical pathways has the potential to improve the mechanics of breathing and hence ventilation. PMID:17412776

  3. [Invasive mechanical ventilation in COPD and asthma].

    PubMed

    García Vicente, E; Sandoval Almengor, J C; Díaz Caballero, L A; Salgado Campo, J C

    2011-01-01

    COPD and asthmatic patients use a substantial proportion of mechanical ventilation in the ICU, and their overall mortality with ventilatory support can be significant. From the pathophysiological standpoint, they have increased airway resistance, pulmonary hyperinflation, and high pulmonary dead space, leading to increased work of breathing. If ventilatory demand exceeds work output of the respiratory muscles, acute respiratory failure follows. The main goal of mechanical ventilation in this kind of patients is to improve pulmonary gas exchange and to allow for sufficient rest of compromised respiratory muscles to recover from the fatigued state. The current evidence supports the use of noninvasive positive-pressure ventilation for these patients (especially in COPD), but invasive ventilation also is required frequently in patients who have more severe disease. The physician must be cautious to avoid complications related to mechanical ventilation during ventilatory support. One major cause of the morbidity and mortality arising during mechanical ventilation in these patients is excessive dynamic pulmonary hyperinflation (DH) with intrinsic positive end-expiratory pressure (intrinsic PEEP or auto-PEEP). The purpose of this article is to provide a concise update of the most relevant aspects for the optimal ventilatory management in these patients. PMID:21216495

  4. 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

  5. Gender imbalance in living kidney donation in Switzerland.

    PubMed

    Thiel, G T; Nolte, C; Tsinalis, D

    2005-03-01

    Gender characteristics were analyzed in 631 living kidney donors followed by the Swiss Organ Living Donor Health Registry (SOL-DHR) from 1993 to 2003; 65% of kidney donors were women and 64% of recipients were men. The proportion remained stable over the years and in different donor age classes from 25 to 74 years. The observed rate of female life partners giving their kidneys to male life partners was significantly higher than expected (P < .005). After exclusion of spousal pairs, the observed rate of gender pairing in all 4 possible directions differed significantly from the expected rate (P < .0001). Men were always behind the expected rate for kidney donation and women ahead. The main 3 reasons for gender imbalance in living kidney donors in Switzerland are the higher risk of men to acquire end-stage renal failure, financial risks for main breadwinners and the traditional female role in family life. Measures are proposed to narrow the gap between expected and observed gender balance in living organ donation. PMID:15848467

  6. Digital single-nucleotide polymorphism analysis for allelic imbalance.

    PubMed

    Chang, Hsueh-Wei; Shih, Ie-Ming

    2005-01-01

    Digital single-nucleotide polymorphism (SNP) analysis is developed to amplify a single template from a pool of DNA samples, thereby generating the amplicons that are homogeneous in sequence. Different fluorophores are then applied as probes to detect and discriminate different alleles (paternal vs maternal alleles or wild-type vs mutant), which can be readily counted. In this way, digital SNP analysis transforms the exponential and analog signals from conventional polymerase chain reaction (PCR) to linear and digital ones. Digital SNP analysis has the following advantages. First, statistical analysis of the PCR products becomes available as the alleles can be directly counted. Second, this technology is designed to generate PCR products of the same size; therefore, DNA degradation would not be a problem as it commonly occurs when microsatellite markers are used to assess allelic status in clinical samples. Last, digital SNP analysis is designed to amplify a relatively small amount of DNA samples, which is available in some clinical samples. Digital SNP analysis has been applied in quantification of mutant alleles and detection of allelic imbalance in clinical specimens and it represents another example of the power of PCR and provides unprecedented opportunities for molecular genetic analysis. PMID:15542903

  7. 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

  8. 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.

  9. Whole Animal Perfusion Fixation for Rodents

    PubMed Central

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

    2012-01-01

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

  10. 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

  11. 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.

  12. Clinical myocardial perfusion PET/CT.

    PubMed

    Di Carli, Marcelo F; Dorbala, Sharmila; Meserve, Jolene; El Fakhri, Georges; Sitek, Arkadiusz; Moore, Stephen C

    2007-05-01

    The field of nuclear cardiology is witnessing growing interest in the use of cardiac PET for the evaluation of patients with coronary artery disease (CAD). The available evidence suggests that myocardial perfusion PET provides an accurate means for diagnosing obstructive CAD, which appears superior to SPECT especially in the obese and in those undergoing pharmacologic stress. The ability to record changes in left ventricular function from rest to peak stress and to quantify myocardial perfusion (in mL/min/g of tissue) provides an added advantage over SPECT for evaluating multivessel CAD. There is growing and consistent evidence that gated myocardial perfusion PET also provides clinically useful risk stratification. Although the introduction of hybrid PET/CT technology offers the exciting possibility of assessing the extent of anatomic CAD (CT coronary angiography) and its functional consequences (ischemic burden) in the same setting, there are technical challenges in the implementation of CT-based transmission imaging for attenuation correction. Nonetheless, this integrated platform for assessing anatomy and biology offers a great potential for translating advances in molecularly targeted imaging into humans. PMID:17475968

  13. [Effect of guided ventilation on gas exchange in kypho-scoliotic patients in post-intensive care].

    PubMed

    Breant, J; Fleury, M F; Delque, G; Vascaut, L

    1989-01-01

    Post-intensive care stabilized kyphoscoliotic patients are characterized by a limited circulation which reduces VCO in relation to VCO2 (specific VCO, Sp VCO) by diminution of the "contact time". This might help in explaining the hypoxaemia observed in these patients concurrently with alveolar hypoventilation and altered ventilation/perfusion ratio. Bradypnoea (Bp) may reduce the last two factors but not the vascular field amputation. In 10 kyphoscoliotic patients examined in spontaneous ventilation (SV), then in Bp, gas exchanges were evaluated under their 2 aspects: gas flow rates and ventilatory efficiency (ERCO2, VA/V). The results obtained in 16 examinations concerning 10 patients were analysed. There were great differences in the amplitude of ventilatory response, a significant increase of VA improving PaCO2 more constantly than PaO2, a slight increase of Sp VCO and a decrease of VCO/VA. In the discussion, ERCO2 and VA/V are compared, the high VA/V and VD/VT values are justified, the uncertain effect of Bp on PaO2 is confirmed, and the relationship of Sp VCO with DuCO and PaO2 is determined. The evaluation of exchanges in SV and Bp provides information on the degree of deterioration of blood perfusion, the physiopathology of each individual subject and the advisability of kinesitherapy with Bp. PMID:2626636

  14. 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

  15. 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

  16. CT Perfusion Dynamics of Intracranial Tuberculomas

    PubMed Central

    N., Jayakumar Peruvumba; Shivashankar, Ravishankar

    2015-01-01

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

  17. Computational fluid dynamics in ventilation. 5: New developments in CFD with relevance to ventilation

    Microsoft Academic Search

    Peter V. Nielsen

    1993-01-01

    Overhead graphics illustrating new developments in computational fluid dynamics (CFD) which are relevant to ventilation are presented. They cover: normalized variables in a room with mixing ventilation; penetration of a wall jet into a room; CFD and cooling load calculation; areas with analytical description of flow elements; local grid refinement; and large eddy simulation.

  18. Ventilation Effectiveness in a Partitioned Office with Displacement Ventilation Determined by Computer Simulation

    Microsoft Academic Search

    Z. Jiang; F. Haghighat

    1993-01-01

    Unlike conventional ventilation systems, the displacement ventilation system supplies air in the low region of a room, while the exhaust opening is usually placed near the ceiling. When partitions are used in the occupied zone, the diffusion of supply air may be obstructed; thus, the existence of the partition may present important effects on air diffusion, retarding the removal of

  19. Percutaneous transtracheal jet ventilation for cardiopulmonary resuscitation: evaluation of a new jet ventilator.

    PubMed

    Swartzman, S; Wilson, M A; Hoff, B H; Bunegin, L; Smith, R B; Sjostrand, U

    1984-01-01

    This study compared percutaneous transtracheal jet ventilation (PTJV) at a frequency (f) of 20/min, with high-frequency positive-pressure ventilation (HFPPV) at f of 60/min, and endotracheal intubation and intermittent positive-pressure ventilation (ET IPPV) at f of 10/min in apneic dogs. Fifty-four emergency medicine trainees (EMTs) attempted PTJV via a 14-gauge Angiocath attached to a hand-held jet ventilator, f of 20/min, and ET IPPV using an Ambu bag, f of 10/min. Twenty-nine other EMTs attempted cricothyrotomy using a prototype nonkinkable catheter (Arrow) and a new jet ventilator, Bronchovent, f of 60/min, equipped with a pressure sensor which stops ventilation at pressures greater than 20 cm H2O. Adequate oxygenation was achieved by all 3 groups, but only the HFPPV group avoided respiratory alkalosis. There was a higher equipment failure rate (catheter kinking and dislodgment) in the PTJV group. In the HFPPV group, the Bronchovent's pressure-limiting sensor stopped ventilation when the catheter was kinked or out of position, reducing the extent of subcutaneous emphysema and barotrauma. With further catheter improvements, HFPPV Bronchovent may offer a safe and reliable method of ventilating patients during CPR in the field. PMID:6360535

  20. Characteristics of rain penetration through a gravity ventilator used for natural ventilation.

    PubMed

    Kim, Taehyeung; Lee, Dong Ho; Ahn, Kwangseog; Ha, Hyunchul; Park, Heechang; Piao, Cheng Xu; Li, Xiaoyu; Seo, Jeoungyoon

    2008-01-01

    Gravity ventilators rely simply on air buoyancy to extract air and are widely used to exhaust air contaminants and heat from workplaces using minimal energy. They are designed to maximize the exhaust flow rate, but the rain penetration sometimes causes malfunctioning. In this study, the characteristics of rain penetration through a ventilator were examined as a preliminary study to develop a ventilator with the maximum exhaust capacity while minimizing rain penetration. A model ventilator was built and exposed to artificial rain and wind. The paths, intensities and amounts of penetration through the ventilator were observed and measured in qualitative and quantitative fashions. In the first phase, the pathways and intensities of rain penetration were visually observed. In the second phase, the amounts of rain penetration were quantitatively measured under the different configurations of ventilator components that were installed based on the information obtained in the first-phase experiment. The effects of wind speed, grill direction, rain drainage width, outer wall height, neck height and leaning angle of the outer wall from the vertical position were analyzed. Wind speed significantly affected rain penetration. Under the low crosswind conditions, the rain penetration intensities were under the limit of detection. Under the high crosswind conditions, grill direction and neck height were the most significant factors in reducing rain penetration. The installation of rain drainage was also important in reducing rain penetration. The experimental results suggest that, with proper configurations of its components, a gravity ventilator can be used for natural ventilation without significant rain penetration problems. PMID:18065399

  1. Mechanical ventilation in the newborn; a simplified approach. Part 2: High-frequency ventilation.

    PubMed

    Muhlethaler, Vincent; Malcolm, Girvan

    2014-10-01

    High frequency oscillatory ventilation (HFOV) is becoming an increasingly popular intervention in the neonatal intensive care unit. This article will attempt to explain the principles of HFOV. It is inherently more difficult to become skilled in this technique than in other forms of mechanical ventilation, so caution is warranted. PMID:20977521

  2. Non-invasive ventilation and continuous positive pressure ventilation in emergency departments: where are we now?

    Microsoft Academic Search

    R Bolton; A Bleetman

    2008-01-01

    A number of emergency departments have introduced non-invasive positive pressure ventilation (NIV) and continuous positive airway pressure (CPAP) for patients presenting with acute respiratory failure. It is thought that early non-invasive respiratory support will avoid the need for invasive ventilation in many cases. This literature review studied current knowledge of NIV and CPAP in the acute setting with the aim

  3. Modeling study of ventilation, IAQ and energy impacts of residential mechanical ventilation

    Microsoft Academic Search

    Persily

    1998-01-01

    This paper reports on a simulation study of indoor air quality, ventilation and energy impacts of several mechanical ventilation approaches in a single-family residential building. The study focused on a fictitious two-story house in Spokane, Washington and employed the multizone airflow and contaminant dispersal model CONTAM. The model of the house included a number of factors related to airflow including

  4. Effect of vasodilators on pulmonary perfusion defects in asthma using sequential Kr-81m perfusion imaging

    SciTech Connect

    Ertle, A.R.; Tashkin, D.P.; Webber, M.M.; Soffer, M.J.; Frank, G.W.

    1984-01-01

    The investigation was undertaken to determine if vasodilator agents may enhance the diagnostic utility of perfusion lung imaging (Q) by normalizing regional perfusion abnormalities in bronchospastic patients. The effect of oxygen (02), nitroglycerine (NTG), hydralazine (H), and nifedipine (N) on regional lung perfusion defects was studied in 6 mild to severe asthmatics (ages defects was studied in 6 mild to severe asthmatics (ages 31-72yrs) using sequential Kr-81m imaging which permits repetitive imaging due to very low radiation dose and 13 sec T-1/2. Each patient was studied once weekly for 3 wks. Baseline Q scans were obtained using 10mCi of I.V. Kr-81m. the best view showing perfusion defects was used for subsequent images. At each visits, 30% 02 by ventimask was given for 20 min followed by a repeat Q scan. Subsequently, on separate visits, subjects were given either 1 dose of sublingual (sl)N 20 mg or 2 doses (1 hr between) of s1 NTG 1/150gr or po H 25mg according to a random-order crossover design. Q scans were obtained 2 min after NTG, 60 min after H, and 30 and 60 min after N. 30% 02 was given again for 20 min, and a final scan was obtained. Scan were reviewed by 2 observers and showed relatively fixed defects in 4 pts improvement in defects in 3 pts with NTG, 1 with N, 1 with H, and 2 with 02 alone. Additive effects of 02 and N or NTG were seen in 2 pts. These preliminary results suggest that vasodilators and 02 may improve regional perfusion in patients with bronchospastic disease and that this effect may be additive. These medications may thus improve the specificity of perfusion lung scanning in the diagnostic evaluation of pulmonary embolism.

  5. 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

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

    PubMed Central

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

    2010-01-01

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

  7. Carbon-dioxide-controlled ventilation study

    SciTech Connect

    McMordie, K.L.; Carroll, D.M.

    1994-05-01

    The In-House Energy Management (IHEM) Program has been established by the U.S. Department of Energy to provide funds to federal laboratories to conduct research on energy-efficient technology. The Energy Sciences Department of Pacific Northwest Laboratory (PNL) was tasked by IHEM to research the energy savings potential associated with reducing outdoor-air ventilation of buildings. By monitoring carbon dioxide (CO{sub 2}) levels in a building, outdoor air provided by the heating, ventilating, and air-conditioning (HVAC) system can be reduced to the percentage required to maintain satisfactory CO{sub 2} levels rather than ventilating with a higher outdoor-air percentage based on an arbitrary minimum outdoor-air setting. During summer months, warm outdoor air brought into a building for ventilation must be cooled to meet the appropriate cooling supply-air temperature, and during winter months, cold outdoor air must be heated. By minimizing the amount of hot or cold outdoor air brought into the HVAC system, the supply air requires less cooling or heating, saving energy and money. Additionally, the CO{sub 2} levels in a building can be monitored to ensure that adequate outdoor air is supplied to a building to maintain air quality levels. The two main considerations prior to implementing CO{sub 2}-based ventilation control are its impact on energy consumption and the adequacy of indoor air quality (IAQ) and occupant comfort. To address these considerations, six portable CO{sub 2} monitors were placed in several Hanford Site buildings to estimate the adequacy of office/workspace ventilation. The monitors assessed the potential for reducing the flow of outdoor-air to the buildings. A candidate building was also identified to monitor various ventilation control strategies for use in developing a plan for implementing and assessing energy savings.

  8. 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.

  9. Perfusion CT imaging of the liver: review of clinical applications

    PubMed Central

    O?ul, Hayri; Kantarc?, Mecit; Genç, Berhan; Pirimo?lu, Berhan; Çullu, Ne?at; K?zrak, Ye?im; Y?lmaz, Ömer; Karabulut, Nevzat

    2014-01-01

    Perfusion computed tomography (CT) has a great potential for determining hepatic and portal blood flow; it offers the advantages of quantitative determination of lesion hemodynamics, distinguishing malignant and benign processes, as well as providing morphological data. Many studies have reported the use of this method in the assessment of hepatic tumors, hepatic fibrosis associated with chronic liver disease, treatment response following radiotherapy and chemotherapy, and hepatic perfusion changes after radiological or surgical interventions. The main goal of liver perfusion imaging is to improve the accuracy in the characterization of liver disorders. In this study, we reviewed the clinical application of perfusion CT in various hepatic diseases. PMID:24834487

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

    E-print Network

    Izamis, Maria-Louisa, 1979-

    2006-01-01

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

  11. Detection of reactive oxygen species in isolated, perfused lungs by electron spin resonance spectroscopy

    PubMed Central

    Weissmann, Norbert; Kuzkaya, Nermin; Fuchs, Beate; Tiyerili, Vedat; Schäfer, Rolf U; Schütte, Hartwig; Ghofrani, Hossein A; Schermuly, Ralph T; Schudt, Christian; Sydykov, Akylbek; Egemnazarow, Bakytbek; Seeger, Werner; Grimminger, Friedrich

    2005-01-01

    Background The sources and measurement of reactive oxygen species (ROS) in intact organs are largely unresolved. This may be related to methodological problems associated with the techniques currently employed for ROS detection. Electron spin resonance (ESR) with spin trapping is a specific method for ROS detection, and may address some these technical problems. Methods We have established a protocol for the measurement of intravascular ROS release from isolated buffer-perfused and ventilated rabbit and mouse lungs, combining lung perfusion with the spin probe l-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CPH) and ESR spectroscopy. We then employed this technique to characterize hypoxia-dependent ROS release, with specific attention paid to NADPH oxidase-dependent superoxide formation as a possible vasoconstrictor pathway. Results While perfusing lungs with CPH over a range of inspired oxygen concentrations (1–21 %), the rate of CP• formation exhibited an oxygen-dependence, with a minimum at 2.5 % O2. Addition of superoxide dismutase (SOD) to the buffer fluid illustrated that a minor proportion of this intravascular ROS leak was attributable to superoxide. Stimulation of the lungs by injection of phorbol-12-myristate-13-acetate (PMA) into the pulmonary artery caused a rapid increase in CP• formation, concomitant with pulmonary vasoconstriction. Both the PMA-induced CPH oxidation and the vasoconstrictor response were largely suppressed by SOD. When the PMA challenge was performed at different oxygen concentrations, maximum superoxide liberation and pulmonary vasoconstriction occurred at 5 % O2. Using a NADPH oxidase inhibitor and NADPH-oxidase deficient mice, we illustrated that the PMA-induced superoxide release was attributable to the stimulation of NADPH oxidases. Conclusion The perfusion of isolated lungs with CPH is suitable for detection of intravascular ROS release by ESR spectroscopy. We employed this technique to demonstrate that 1) PMA-induced vasoconstriction is caused "directly" by superoxide generated from NADPH oxidases and 2) this pathway is pronounced in hypoxia. NADPH oxidases thus may contribute to the hypoxia-dependent regulation of pulmonary vascular tone. PMID:16053530

  12. Copper Imbalances in Ruminants and Humans: Unexpected Common Ground1

    PubMed Central

    Suttle, Neville F.

    2012-01-01

    Ruminants are more vulnerable to copper deficiency than humans because rumen sulfide generation lowers copper availability from forage, increasing the risk of conditions such as swayback in lambs. Molybdenum-rich pastures promote thiomolybdate (TM) synthesis and formation of unabsorbable Cu-TM complexes, turning risk to clinical reality (hypocuprosis). Selection pressures created ruminant species with tolerance of deficiency but vulnerability to copper toxicity in alien environments, such as specific pathogen–free units. By contrast, cases of copper imbalance in humans seemed confined to rare genetic aberrations of copper metabolism. Recent descriptions of human swayback and the exploratory use of TM for the treatment of Wilson’s disease, tumor growth, inflammatory diseases, and Alzheimer’s disease have created unexpected common ground. The incidence of pre–hemolytic copper poisoning in specific pathogen–free lambs was reduced by an infection with Mycobacterium avium that left them more responsive to treatment with TM but vulnerable to long-term copper depletion. Copper requirements in ruminants and humans may need an extra allowance for the “copper cost” of immunity to infection. Residual cuproenzyme inhibition in TM-treated lambs and anomalies in plasma copper composition that appeared to depend on liver copper status raise this question “can chelating capacity be harnessed without inducing copper-deficiency in ruminants or humans?” A model of equilibria between exogenous (TM) and endogenous chelators (e.g., albumin, metallothionein) is used to predict risk of exposure and hypocuprosis; although risk of natural exposure in humans is remote, vulnerability to TM-induced copper deficiency may be high. Biomarkers of TM impact are needed, and copper chaperones for inhibited cuproenzymes are prime candidates. PMID:22983845

  13. Metal-insulator transition induced by mass imbalance in a three-component Hubbard model

    NASA Astrophysics Data System (ADS)

    Nguyen, Duong-Bo; Phung, Duy-Khuong; Phan, Van-Nham; Tran, Minh-Tien

    2015-03-01

    The effects of mass imbalance in a three-component Hubbard model are studied by the dynamical mean-field theory combined with exact diagonalization. The model describes a fermion-fermion mixture of two different particle species with a mass imbalance. One species is two-component fermion particles, and the other is single-component ones. The local interaction between particle species is considered isotropically. It is found that the mass imbalance can drive the mixture from insulator to metal. The insulator-metal transition is a species-selective-like transition of lighter mass particles and occurs only at commensurate particle densities and moderate local interactions. For weak and strong local interactions the mass imbalance does not change the ground state of the mixture.

  14. An Incremental Learning Algorithm for Non-Stationary Environments and Class Imbalance

    E-print Network

    Polikar, Robi

    drifting data streams. Several existing approaches for learning concept drift use a sliding time window, class imbalance I. INTRODUCTION Learning in non-stationary environments (NSE), also called concept drift

  15. Are foreign investments in land leading to an imbalance in the hydrological cycle?

    NASA Astrophysics Data System (ADS)

    Steenhuis, T. S.; Theodore, C.; Makki, F. M.

    2012-12-01

    Over the past few years, large-scale acquisitions of farmland have taken place across the world. Although the land acquisitions are generally portrayed as a land grab in Africa, in almost all cases it is the extra water that is consumed by the crops that brings a new imbalance in the hydrological science. Understanding the imbalance is central to livelihoods and food security of the people downstream because almost all rivers in Africa with the exception of the Congo are being fully consumed before they enter the ocean. In this talk we will show what the effects on the water imbalance caused by foreign and national investments in the Blue Nile basin in the Ethiopian highlands has on the water availability in the downstream countries and whether the imbalance can be made up by increasing irrigation efficiency.

  16. Decreased accuracy of pulse oximetry measurements during low perfusion caused by sepsis: is the perfusion index of any value?

    Microsoft Academic Search

    Helmut D. Hummler; Anja Engelmann; Frank Pohlandt; Josef Högel; Axel R. Franz

    2006-01-01

    Objective  To evaluate the effects of deteriorating perfusion caused by sepsis on the accuracy of pulse oximetry measurements using two more recently available techniques (Nellcor N-395 and Masimo Radical) and to evaluate the perfusion index as a marker of impaired peripheral perfusion to indicate that accuracy of pulse oximetry readings may be affected.Design and setting  Interventional cohort study in a university animal research facility.Subjects  Thirty-seven

  17. Prism adaptation to rightward optical deviation improves postural imbalance in left-hemiparetic patients

    Microsoft Academic Search

    Caroline Tilikete; Gilles Rode; Yves Rossetti; Jacques Pichon; Ling Li; Dominique Boisson

    2001-01-01

    Left-hemiparetic patients show predominant postural imbalance as compared to right-hemiparetic patients. The right hemisphere is crucial for generating internal maps used for perceptual and premotor processing of spatial information. Predominant postural imbalance with right-brain damage could thus result from a distortion of an internal postural map. Well-known manifestations of distorted internal maps due to right-hemisphere lesions, such as hemineglect, may

  18. The effect of teeth-on-stator labyrinth seals on rotor imbalance response 

    E-print Network

    Conway, Eileen Marie

    1991-01-01

    . The test rig is modeled as an overhung rotor-bearing system with the seal section located at the overhung mtor section. RIGIDROTOR simulates the test rig's response to imbalance. Coastdowns are performed with the test rig to obtain the experimental... vector with magnitude and phase. Balancing at selected speeds reduces vibration amplitude. 2. 2. 6 Rotor Balancing The objective of mtor balancing is to nnnimize the effects of mtor residual imbalance on the system during normal openuion. The main...

  19. Blind I\\/Q imbalance compensation using independent component analysis in MIMO OFDM systems

    Microsoft Academic Search

    Jingbo Gao; Xu Zhu; Hai Lin; Asoke K. Nandi

    2009-01-01

    I\\/Q imbalance, which is one of the radio frequency (RF) circuit impairments in direct conversion transmitter and receiver, introduces severe performance degradation in wireless communication systems. In this paper, we propose a novel blind compensation algorithm for both frequency-dependent and frequency-independent I\\/Q imbalance based on independent component analysis (ICA) in multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM)

  20. An empirical study on ensemble selection for class-imbalance data sets

    Microsoft Academic Search

    Che Junfei; Wu Qingfeng; Dong Huailin

    2010-01-01

    The algorithm of GASEN (Genetic Algorithm based Selective Ensemble Network) has been proven to be a very effective way to select a subset of neural networks to form an ensemble classifier or a regressor of enhanced generation ability. And yet performance of GASEN on class-imbalance data sets hasn't been discussed widely, while class-imbalance learning itself is an increasingly important issue.

  1. Evaluation of pulmonary dysfunctions and acid–base imbalances induced by Chlamydia psittaci in a bovine model of respiratory infection

    PubMed Central

    2014-01-01

    Background Chlamydia psittaci (Cp) is a respiratory pathogen capable of inducing acute pulmonary zoonotic disease (psittacosis) or persistent infection. To elucidate the pathogenesis of this infection, a translational large animal model was recently introduced by our group. This study aims at quantifying and differentiating pulmonary dysfunction and acid–base imbalances induced by Cp. Methods Forty-two calves were grouped in (i) animals inoculated with Cp (n?=?21) and (ii) controls sham-inoculated with uninfected cell culture (n?=?21). For pulmonary function testing, impulse oscillometry, capnography, and FRC (functional residual capacity) measurement were applied to spontaneously breathing animals. Variables of acid–base status were assessed in venous blood using both (i) traditional Henderson-Hasselbalch and (ii) strong ion approach. Results Both obstructive and restrictive pulmonary disorders were induced in calves experimentally inoculated with Cp. Although disorders in respiratory mechanics lasted for 8–11 days, the pattern of spontaneous breathing was mainly altered in the period of acute illness (until 4 days post inoculation, dpi). Expiration was more impaired than inspiration, resulting in elevated FRC. Ventilation was characterised by a reduction in tidal volume (?25%) combined with an increased percentage of dead space volume and a significant reduction of alveolar volume by 10%. Minute ventilation increased significantly (+50%) due to a compensatory doubling of respiratory rate. Hyperventilatory hypocapnia at 2–3 dpi resulted in slightly increased blood pH at 2 dpi. However, the acid–base equilibrium was additionally influenced by metabolic components, i.e. the systemic inflammatory response, all of which were detected with help of the strong ion theory. Decreased concentrations of albumin (2–10 dpi), a negative acute-phase marker, resulted in a decrease in the sum of non-volatile weak acids (Atot), revealing an alkalotic effect. This was counterbalanced by acidic effects of decreased strong ion difference (SID), mediated by the interplay between hypochloraemia (alkalotic effect) and hyponatraemia (acidic effect). Conclusions This bovine model was found to be suitable for studying pathophysiology of respiratory Cp infection and may help elucidating functional host-pathogen interactions in the mammalian lung. PMID:24517577

  2. Effects of specific muscle imbalance improvement training on the balance ability in elite fencers

    PubMed Central

    Kim, Taewhan; Kil, Sekee; Chung, Jinwook; Moon, Jeheon; Oh, Eunyoung

    2015-01-01

    [Purpose] The lunge Motion that occurs frequently in fencing training and matches results in imbalance of the upper and lower limbs muscles. This research focuses on the improvement of the imbalance that occurs in the national team fencers of the Republic of Korea through specific muscle imbalance improvement training. [Subjects] The subjects of this research were limited to right-handed male fencers. Nine male, right-handed national fencing athletes were selected for this study (4 epee, 5 sabre; age 28.2 ± 2.2?years; height 182.3 ± 4.0?cm; weight 76.5 ± 8.2?kg; experience 12.4 ± 3.0?years). [Methods] The specific muscle imbalance improvement training program was performed for 12 weeks and Pre-Post tests were to evaluate its effect on the experimental group. Measurements comprised anthropometry, test of balance, and movement analysis. [Results] After the training program, mediolateral sway of the nondominant lower limb and the balance scale showed statistically significant improvement. [Conclusion] The specific muscle imbalance improvement training program used in this research was proven to be effective for improving the muscle imbalance of elite fencers.

  3. Tree imbalance causes a bias in phylogenetic estimation of evolutionary timescales using heterochronous sequences.

    PubMed

    Duchêne, David; Duchêne, Sebastian; Ho, Simon Y W

    2015-07-01

    Phylogenetic estimation of evolutionary timescales has become routine in biology, forming the basis of a wide range of evolutionary and ecological studies. However, there are various sources of bias that can affect these estimates. We investigated whether tree imbalance, a property that is commonly observed in phylogenetic trees, can lead to reduced accuracy or precision of phylogenetic timescale estimates. We analysed simulated data sets with calibrations at internal nodes and at the tips, taking into consideration different calibration schemes and levels of tree imbalance. We also investigated the effect of tree imbalance on two empirical data sets: mitogenomes from primates and serial samples of the African swine fever virus. In analyses calibrated using dated, heterochronous tips, we found that tree imbalance had a detrimental impact on precision and produced a bias in which the overall timescale was underestimated. A pronounced effect was observed in analyses with shallow calibrations. The greatest decreases in accuracy usually occurred in the age estimates for medium and deep nodes of the tree. In contrast, analyses calibrated at internal nodes did not display a reduction in estimation accuracy or precision due to tree imbalance. Our results suggest that molecular-clock analyses can be improved by increasing taxon sampling, with the specific aims of including deeper calibrations, breaking up long branches and reducing tree imbalance. PMID:25431227

  4. Ethical and Legal Implications of Elective Ventilation and Organ Transplantation: “Medicalization” of Dying versus Medical Mission

    PubMed Central

    Frati, Paola; Montanari Vergallo, Gianluca; Di Luca, Natale Mario; Turillazzi, Emanuela

    2014-01-01

    A critical controversy surrounds the type of allowable interventions to be carried out in patients who are potential organ donors, in an attempt to improve organ perfusion and successful transplantation. The main goal is to transplant an organ in conditions as close as possible to its physiological live state. “Elective ventilation” (EV), that is, the use of ventilation for the sole purpose of retrieving the organs of patients close to death, is an option which offsets the shortage of organ donation. We have analyzed the legal context of the dying process of the organ donor and the feasibility of EV in the Italian context. There is no legal framework regulating the practice of EV, neither is any real information given to the general public. A public debate has yet to be initiated. In the Italian cultural and legislative scenario, we believe that, under some circumstances (i.e., the expressed wishes of the patient, even in the form of advance directives), the use of EV does not violate the principle of beneficence. We believe that the crux of the matter lies in the need to explore the real determination and will of the patient and his/her orientation towards the specific aim of organ donation. PMID:25126582

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

    PubMed

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

    1986-03-01

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

  6. AutoCAD based mine ventilation analysis

    SciTech Connect

    Sartain, T.; Scheck, D.

    1999-07-01

    MineVent is a mine ventilation analysis system which runs inside AutoCAD and uses the Penn State and other ventilation simulators. Working from AutoCAD as-mined and projected mine maps, the user picks the node locations and connects them with branches that correspond to the airway paths. Where survey data are not available, the system uses formulas to compute resistances. The system prompts the user for necessary parameters but the branch lengths are automatically computed. Powerful editing features reduce the time to modify existing schematics and try alternative ventilation options. The system also includes a survey data reduction module which outputs pressure drops and quantities values to feed the branch resistance calculator. Output includes color coded schematics with pressures and quantities shown. If the fan curve data have been digitized, the fan operating points are shown on the curves. Tabular output is also available.

  7. Elective ventilation of potential organ donors.

    PubMed Central

    Riad, H.; Nicholls, A.; Neuberger, J.; Willatts, S. M.; Sells, R. A.; Jones, M. A.; Francis, R.

    1995-01-01

    Elective ventilation describes the procedure of transferring selected patients dying from rapidly progressive intracranial haemorrhage from general medical wards to intensive care units for a brief period of ventilation before confirmation of brain stem death and harvesting of organs. This approach in Exeter has led to a rate of kidney retrieval and transplant higher than has been achieved elsewhere in the United Kingdom, with a stabilisation of numbers on patients on dialysis. Recently doubt has been cast on the legality of our practice of elective ventilation on the grounds that relatives are not permitted to consent to treatment of an incompetent person when that treatment is not in the patient's best interests. We are thus faced with the dilemma of a protocol that is ethical, practical, and operates for the greater good but which may be illegal. This article explores various objections to the protocol and calls for public, medical, and legal debate on the issues. PMID:7711541

  8. Home Mechanical Ventilation in South Korea

    PubMed Central

    Kim, Dong Hyun; Choi, Won Ah

    2014-01-01

    Purpose To survey the use of invasive and noninvasive home mechanical ventilation (HMV) methods in South Korea from the perspective of physical medicine and rehabilitation (PM&R). Materials and Methods For 413 users of HMV, retrospective reviews of PM&R interventions and survey of HMV methods employed from Mar 2000 to Dec 2009. Results Of the 413 users, the majority of whom with progressive neuromuscular disorders (NMDs) (n=358), 284 patients initially used noninvasive mechanical ventilation (NIV), while 63 others who were using tracheostomy mechanical ventilation switched to NIV as part of their rehabilitation. The NMD patients began HMV at an earlier age (34.9±20.3 yrs), and used for longer (14.7±7.5) hours than patients with non-neuromuscular causes of respiratory impairment. Conclusion Noninvasive management was preferred over invasive ones, and transition to the former was a result of PM&R interventions. PMID:25323913

  9. Fire smoke ventilation through shafts: Experiments

    NASA Astrophysics Data System (ADS)

    Nireus, K.; Werling, P. O.; Hansson, S. G.; Onnermark, B.

    1994-06-01

    An experimental investigation studied the fire smoke filling of a large compartment (6 x 6 x 6 m) ventilated through shafts of various heights (0, 2, 4, 6 m). The fuel was kerosene. The experiments measured the optical smoke density (OD) and the gas temperature (T) at various heights. By visual observation the height of the smoke layer (h) was measured. The result of the investigation was primarily the large collection of data (OD, T, h) to be used in future tests of calculation models. Directly observed was only a weak correlation between the smoke filling and the heights of the ventilation shafts.

  10. Preoperational test report, recirculation ventilation systems

    SciTech Connect

    Clifton, F.T.

    1997-11-11

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  11. Ways of improving economy and reliability of mine ventilation

    SciTech Connect

    N.N. Petrov; N.A. Popov [Russian Academy of Sciences, Novosibirsk (Russian Federation). Institute of Mining

    2004-09-01

    It is established that mine ventilation by main fans operating at maximum capacity results in higher power consumption. The ways are proposed for reduction in the effective power consumption by ventilation and improvement of mining operation safety.

  12. Elective ventilation for organ donation: law, policy and public ethics

    PubMed Central

    Coggon, John

    2013-01-01

    This paper examines questions concerning elective ventilation, contextualised within English law and policy. It presents the general debate with reference both to the Exeter Protocol on elective ventilation, and the considerable developments in legal principle since the time that that protocol was declared to be unlawful. I distinguish different aspects of what might be labelled elective ventilation policies under the following four headings: ‘basic elective ventilation’; ‘epistemically complex elective ventilation’; ‘practically complex elective ventilation’; and ‘epistemically and practically complex elective ventilation’. I give a legal analysis of each. In concluding remarks on their potential practical viability, I emphasise the importance not just of ascertaining the legal and ethical acceptability of these and other forms of elective ventilation, but also of assessing their professional and political acceptability. This importance relates both to the successful implementation of the individual practices, and to guarding against possible harmful effects in the wider efforts to increase the rates of posthumous organ donation. PMID:23222143

  13. Natural ventilation : design for suburban houses in Thailand

    E-print Network

    Tantasavasdi, Chalermwat, 1971-

    1998-01-01

    Natural Ventilation is the most effective passive cooling design strategy for architecture in hot and humid climates. In Thailand, natural ventilation has been the most essential element in the vernacular architecture such ...

  14. Review: Artifical ventilation with positive end-expiratory pressure (PEEP)

    Microsoft Academic Search

    Dag Berger Stokke

    1976-01-01

    CPPV (continuous positive pressure ventilation) is obviously superior to IPPV (intermittent positive pressure ventilation) for the treatment of patients with acute respiratory insufficiency (ARI) and results within a few minutes in a considerable increase in the oxygen transport.

  15. Adaptive support ventilation: State of the art review

    PubMed Central

    Fernández, Jaime; Miguelena, Dayra; Mulett, Hernando; Godoy, Javier; Martinón-Torres, Federico

    2013-01-01

    Mechanical ventilation is one of the most commonly applied interventions in intensive care units. Despite its life-saving role, it can be a risky procedure for the patient if not applied appropriately. To decrease risks, new ventilator modes continue to be developed in an attempt to improve patient outcomes. Advances in ventilator modes include closed-loop systems that facilitate ventilator manipulation of variables based on measured respiratory parameters. Adaptive support ventilation (ASV) is a positive pressure mode of mechanical ventilation that is closed-loop controlled, and automatically adjust based on the patient's requirements. In order to deliver safe and appropriate patient care, clinicians need to achieve a thorough understanding of this mode, including its effects on underlying respiratory mechanics. This article will discuss ASV while emphasizing appropriate ventilator settings, their advantages and disadvantages, their particular effects on oxygenation and ventilation, and the monitoring priorities for clinicians. PMID:23833471

  16. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS...Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent forced...

  17. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS...Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent forced...

  18. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS...Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent forced...

  19. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS...Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent forced...

  20. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS...Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent forced...

  1. VENTILATION RESEARCH: A REVIEW OF RECENT INDOOR AIR QUALITY LITERATURE

    EPA Science Inventory

    The report gives results of a literature review, conducted to survey and summarize recent and ongoing engineering research into building ventilation, air exchange rate, pollutant distribution and dispersion, and other effects of heating, ventilation, and air-conditioning (HVAC) s...

  2. 30 CFR 77.1106 - Battery-charging stations; ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 2012-07-01 false Battery-charging stations; ventilation. 77...COAL MINES Fire Protection § 77.1106 Battery-charging stations; ventilation. Battery-charging stations shall be located in...

  3. 30 CFR 77.1106 - Battery-charging stations; ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 2013-07-01 false Battery-charging stations; ventilation. 77...COAL MINES Fire Protection § 77.1106 Battery-charging stations; ventilation. Battery-charging stations shall be located in...

  4. 30 CFR 77.1106 - Battery-charging stations; ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 2014-07-01 false Battery-charging stations; ventilation. 77...COAL MINES Fire Protection § 77.1106 Battery-charging stations; ventilation. Battery-charging stations shall be located in...

  5. Variability in quantitative cardiac magnetic resonance perfusion analysis

    PubMed Central

    Bratis, K.

    2013-01-01

    By taking advantage of its high spatial resolution, noninvasive and nontoxic nature first-pass perfusion cardiovascular magnetic resonance (CMR) has rendered an indispensable tool for the noninvasive detection of reversible myocardial ischemia. A potential advantage of perfusion CMR is its ability to quantitatively assess perfusion reserve within a myocardial segment, as expressed semi- quantitatively by myocardial perfusion reserve index (MPRI) and fully- quantitatively by absolute myocardial blood flow (MBF). In contrast to the high accuracy and reliability of CMR in evaluating cardiac function and volumes, perfusion CMR is adversely affected by multiple potential reasons during data acquisition as well as post-processing. Various image acquisition techniques, various contrast agents and doses as well as variable blood flow at rest as well as variable reactions to stress all influence the acquired data. Mechanisms underlying the variability in perfusion CMR post processing, as well as their clinical significance, are yet to be fully elucidated. The development of a universal, reproducible, accurate and easily applicable tool in CMR perfusion analysis remains a challenge and will substantially enforce the role of perfusion CMR in improving clinical care. PMID:23825774

  6. Effect of different antiglaucomatous drugs on ocular perfusion pressures.

    PubMed

    Pillunat, L; Stodtmeister, R

    1988-01-01

    In an attempt to elucidate whether antiglaucomatous drugs, especially beta-blockers, affect systemic and/or ocular blood flow, we measured ocular perfusion pressures (PP), systemic blood pressure (BP) and heart rate in 50 healthy subjects before and after topical instillation of the following eye drops: timolol 0.5% (n = 10), betaxolol 0.5% (n = 10), carteolol 2% (n = 10), pilocarpine 2% (n = 10) and acetazolamide 750 mg per os (n = 10). The ocular perfusion pressures were measured by OODG as described by Ulrich. By means of this method--retinal and ciliary perfusion pressure can be recorded separately and simultaneously. Our results indicated that, in spite of a statistically significant decrease in IOP in all 5 groups, there was no change in retinal or ciliary perfusion pressure, heart rate or blood pressure in any of the groups except the carteolol subjects. The ocular perfusion pressures should be increased with reduction of the IOP when the systemic parameters remain unchanged. This was not the case in our experiments and therefore it can be suggested that a relative reduction in ocular perfusion pressure occurs with all agents and, in this respect, timolol and betaxolol did not affect ocular perfusion pressure more than pilocarpine and acetazolamide. Carteolol, however, produced a slight decrease (alpha less than 0.02) in ocular perfusion pressure, in spite of lowering of the IOP. PMID:2904474

  7. Microfluidic Perfusion for Regulating Diffusible Signaling in Stem Cells

    E-print Network

    Voldman, Joel

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

  8. Metabolic Response of Perfused Livers to Various Oxygenation Conditions

    E-print Network

    Androulakis, Ioannis (Yannis)

    in a membrane oxygenator with room air (21% O2) before entering the liver. In the second group, the perfusate. Oxygen and CO2 gradients across the liver were measured periodically with a blood gas analyzer. The rateARTICLE Metabolic Response of Perfused Livers to Various Oxygenation Conditions Mehmet A. Orman,1

  9. Airway Strain during Mechanical Ventilation in an Intact Animal Model

    Microsoft Academic Search

    Scott E. Sinclair; Robert C. Molthen; Steve T. Haworth; Christopher A. Dawson; Christopher M. Waters

    2007-01-01

    Rationale: Mechanical ventilation with large tidal volumes causes ventilator-induced lung injury in animal models. Little direct evi- dence exists regarding the deformation of airways in vivo during mechanical ventilation, or in the presence of positive end-expiratory pressure (PEEP). Objectives: To measure airway strain and to estimate airway wall tension during mechanical ventilation in an intact animal model. Methods: Sprague-Dawley rats

  10. Gram-positive ventilator-associated pneumonia: impact on mortality

    Microsoft Academic Search

    A. R. DE GAUDIO; S. Rinaldi

    Ventilator-associated pneumonia (VAP) is defined as an infection of the lung parenchyma developing during mechanical ventilation,\\u000a usually after at least 2 days of positive-pressure ventilation delivered via an endotracheal tube [1, 2]. This time criterion aims to exclude pneumonias caused by infectious agents already present or incubating before mechanical\\u000a ventilation is started [1]. The diagnosis of VAP is usually based

  11. Analysis of Night Ventilation Potential for Residen tial Buildings in Hot-Humid Climate of Malaysia

    Microsoft Academic Search

    DORIS TOE HOOI CHYEE; TETSU KUBOTA

    This paper discusses the potential of app lying night ventilation as a passive cooling techni que for Malaysian terraced houses based on the results of a full-scal e field experiment. The results revealed that night ventilation provides better diurnal and nocturnal air temperature reduct ions than daytime ventilation, full-day ventilation and no ventilation. Night ventilation improves thermal comfort more tha

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

    SciTech Connect

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

    1986-06-01

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

  13. Hepatic perfusion abnormalities during CT angiography: detection and interpretation.

    PubMed

    Freeny, P C; Marks, W M

    1986-06-01

    Twenty-seven perfusion abnormalities were detected in 17 of 50 patients who underwent computed tomographic angiography (CTA) of the liver. All but one of the perfusion abnormalities occurred in patients with primary or metastatic liver tumors. Perfusion abnormalities were lobar in nine cases, segmental in 11, and subsegmental in seven; 14 were hypoperfusion and 13 were hyperperfusion abnormalities. The causes for the abnormalities included nonperfusion of a replaced hepatic artery (n = 11), cirrhosis and nodular regeneration (n = 3), altered hepatic hemodynamics (e.g., siphoning, laminar flow) caused by tumor (n = 7), contrast media washout from a nonperfused vessel (n = 1), compression of adjacent hepatic parenchyma (n = 1), and unknown (n = 4). Differentiation of perfusion abnormalities from tumor usually can be made by comparing the morphology of the known tumor with the suspected perfusion abnormality, changes of each on delayed CTA scans, and review of initial angiograms and other imaging studies. PMID:3010374

  14. The effect of fabric air permeability on clothing ventilation

    Microsoft Academic Search

    Hiroyuki Ueda; George Havenith

    2005-01-01

    Dry and evaporative heat losses of clothed people are highly affected by the air exchange between the clothing microclimate and the environment. This air exchange, or clothing ventilation, is highly affected by the air permeability of the fabric materials as well as the clothing design. To examine the effect of the air permeability of fabric on clothing ventilation, the ventilation

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

    Microsoft Academic Search

    MARKUS R. OWEN; MARK A. LEWIS; SIAM J. APPL

    1999-01-01

    High frequency ventilation isa radical departure from conventional lung ventilation, with frequenciesgreater than 2 Hz, and volumesper breath much smaller than the anatomical dead- space. Its use has been shown to benefit premature infants and patients with severe respiratory distress, but a vital question concerns ventilator induced damage to the lung tissue, and a clear protocol for the most effective

  16. Proceedings of the 8th US mine ventilation symposium

    Microsoft Academic Search

    Tien

    1999-01-01

    Papers are arranged under the following topical sections: Ventilation system; Longwall safety; Methane and methane control; Methane drainage; Face ventilation; Dust and dust control; Diesel and diesel control; Heat and humidity; Climatic control; Mine explosion; Mine fire and fire detection; Mine fans; Mine monitoring and control; Ventilation modeling; System optimization; Health and safety; and Miscellaneous topics. Papers have been processed

  17. Anxiety sensitivity and ventilator weaning: A preliminary analysis

    Microsoft Academic Search

    Susan Heffelfinger; John E. Calamari; Don E. Workman; Gerry Lawm; Joanne Kelly

    2006-01-01

    Ventilator weaning, the restoration of independent breathing in an individual dependent on mechanically assisted ventilation, involves gradually exposing the individual to longer periods of partially supported or independent breathing. Although ventilator weaning success is importantly related to disease or injury severity, psychological factors have been implicated in weaning outcome but remain significantly understudied. We evaluated the relationship between anxiety sensitivity

  18. Breathing pattern and cost of ventilation in the american alligator

    Microsoft Academic Search

    Tobias Wang; Stephen J. Warburton

    1995-01-01

    The energetic cost of pulmonary ventilation is termed the “cost of breathing” and is commonly determined from the change in oxygen uptake with altered ventilation. Previous analyses of lung mechanics predicts increased tidal volume would be more expensive than increased breathing frequency. Existing studies on the oxidative cost of breathing have, however, not addressed breathing pattern. We stimulated ventilation in

  19. Experimental simulation of wind driven cross-ventilation in a naturally ventilated building

    E-print Network

    Hult, Erin L. (Erin Luelle), 1982-

    2004-01-01

    A device was designed and constructed to simulate cross-ventilation through a building due to natural wind. The wind driver device was designed for use with a one tenth scale model of an open floor plan office building in ...

  20. Management of mechanical ventilation during laparoscopic surgery.

    PubMed

    Valenza, Franco; Chevallard, Giorgio; Fossali, Tommaso; Salice, Valentina; Pizzocri, Marta; Gattinoni, Luciano

    2010-06-01

    Laparoscopy is widely used in the surgical treatment of a number of diseases. Its advantages are generally believed to lie on its minimal invasiveness, better cosmetic outcome and shorter length of hospital stay based on surgical expertise and state-of-the-art equipment. Thousands of laparoscopic surgical procedures performed safely prove that mechanical ventilation during anaesthesia for laparoscopy is well tolerated by a vast majority of patients. However, the effects of pneumoperitoneum are particularly relevant to patients with underlying lung disease as well as to the increasing number of patients with higher-than-normal body mass index. Moreover, many surgical procedures are significantly longer in duration when performed with laparoscopic techniques. Taken together, these factors impose special care for the management of mechanical ventilation during laparoscopic surgery. The purpose of the review is to summarise the consequences of pneumoperitoneum on the standard monitoring of mechanical ventilation during anaesthesia and to discuss the rationale of using a protective ventilation strategy during laparoscopic surgery. The consequences of chest wall derangement occurring during pneumoperitoneum on airway pressure and central venous pressure, together with the role of end-tidal-CO2 monitoring are emphasised. Ventilatory and non-ventilatory strategies to protect the lung are discussed. PMID:20608559

  1. Compartment fire phenomena under limited ventilation

    Microsoft Academic Search

    Yunyong Utiskul; James G. Quintiere; Ali S. Rangwala; Brian A. Ringwelski; Kaoru Wakatsuki; Tomohiro Naruse

    2005-01-01

    Fire behavior of heptane pool fires were investigated in a small-scale 40cm cubic compartment with wall vents at the ceiling (top vent) and the floor (bottom vent). The measurements included pressure, mass loss, temperature, heat flux, and gas mole fraction. Flame oscillations, ghosting, and burning at the air inlet were seen. The regime of limited ventilation was examined to study

  2. Inefficiency of upward displacement operating theatre ventilation.

    PubMed

    Friberg, B; Friberg, S; Burman, L G; Lundholm, R; Ostensson, R

    1996-08-01

    A new thermally based ventilation system ('Floormaster') with inlet of cool clean air at floor level, and evacuation at the ceiling of the air warmed by activity in the room (upward displacement ventilation, 17 air changes/h) was compared with a standard positive pressure (plenum) ventilation system with air supply through an inclined perforated screen along one wall at the ceiling and evacuation at floor level (conventional turbulent or mixing system, 16 air changes/h). The study was made during rigidly standardized sham operations (N = 20) performed in the same operating room by a six-member team wearing non-woven disposable or cotton clothing. In general the upward displacement system removed dust particles too small to carry bacteria (0.16-<0.3 microm, 0.001ventilation systems. PMID:8999051

  3. Measurement of ventilation during cardiopulmonary resuscitation.

    PubMed

    Ornato, J P; Bryson, B L; Donovan, P J; Farquharson, R R; Jaeger, C

    1983-02-01

    Determining adequacy of mechanical ventilation is as important during CPR as in a more stable situation (such as, a patient on a ventilator in an ICU). Yet, such assessment during CPR usually only means listening for breath sounds, checking chest excursion, and blood gases. Exhaled tidal volume (VT) was measured on 45 intubated adult patients during resuscitation using a Wright's spirometer attached to a T-valve above the endotracheal tube. Ten patients had aspiration prior to intubation; 15 received advanced cardiac life support in the field, including esophageal airway insertion. CPR was performed in all cases with a mechanical compression device (Thumper). The pressure ventilator on this device was calibrated (peak inspiratory pressure, VT vs compliance) using a Dixie Test Lung, allowing indirect assessment of pulmonary compliance during CPR. Our findings suggest that lung compliance is markedly reduced within a short time after cardiac arrest. Fifty-five % of patients in this series could not be adequately oxygenated (PaO2 less than 50 torr) despite an FIO2 of 0.8 and adequate ventilation. Due to the reduced cardiac output during CPR causing venoarterial shunting, it is speculated that pulmonary edema is the most plausible explanation for this observation. PMID:6822084

  4. Mine ventilation and air conditioning. 3. edition

    Microsoft Academic Search

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

    1998-01-01

    This revised edition presents an engineering design approach to ventilation and air conditioning as part of the comprehensive environmental control of the mine atmosphere. It provides an in-depth look, for practitioners who design and operate mines, into the health and safety aspects of environmental conditions in the underground workplace. The contents include: Environmental control of the mine atmosphere; Properties and

  5. A sustainable technical system for ventilated façades

    Microsoft Academic Search

    J. Avellaneda; J. M. Gonzalez; A. Carbonnel; D. López

    1. CONSTRUCTION TECHNIQUES FOR THE FAÇADES OF RESIDENTIAL BUILDINGS Façades of residential buildings in Spain have been built usually out of brick. The most com- monly used construction technique (from inner to outer) has consisted of: plaster siding, a 7.5 cm partition wall, an air chamber with neither ventilation nor drainage, thermal insulation of variable thickness and an exterior wall

  6. Noninvasive Home Mechanical Ventilation in Elderly Patients

    Microsoft Academic Search

    Astrid Crespo; Xavier Muñoz; Ferran Torres; Sergi Martí; Jaume Ferrer; Ferran Morell

    2010-01-01

    Study Objective: To determine the short- and long-term benefits of noninvasive home mechanical ventilation (NIHMV) in patients aged 65 and older who were eligible for this treatment. Design and Setting: This retrospective, comparative, longitudinal study was carried out in a tertiary care hospital in Barcelona (Spain). Patients and Methods: The study included all patients in whom NIHMV with a nasal

  7. VENTILATING HORNETS DISPLAY DIFFERENTIAL BODY TEMPERATURE

    Microsoft Academic Search

    Jacob S. Ishay; Marian Plotkin; Natalya Ermakov; Alon Goren; David J. Bergman

    2006-01-01

    abdomen bent downward at a 90? angle to the thorax, their antennae vibrating, and their wings beating rapidly for minutes at a time. Eventually these hornets leave their position, either to retreat into the nest or else to fly off to the field, and are replaced by new hornets that assume the ventilation task. Infra-red (IR) photography reveals that in

  8. Formaldehyde Transfer in Residential Energy Recovery Ventilators

    E-print Network

    supply and exhaust air streams. The wheel, however, can also transfer formaldehyde and other indoor experiments. Key words: energy recovery ventilator, formaldehyde, indoor air quality Highlights: 28 contaminants from the exhaust stream to the supply stream through air leakage, entrainment in the porous wheel

  9. Climate sensitivity of the Antarctic ventilation

    NASA Astrophysics Data System (ADS)

    Ito, T.; Lynch-Stieglitz, J.

    2014-12-01

    Simple box models of ocean-atmosphere carbon cycle predict that Antarctic ventilation can regulate the steady-state atmospheric CO2 through its control over the biological carbon storage in the deep ocean. A weakened upwelling would lead to a more complete nutrient utilization at the surface and an increased retention of biogenic carbon in the deep ocean. We perform a suite of numerical sensitivity experiments using a coupled seaice and global ocean circulation model to better understand what regulates the Antarctic ventilation and its link to glacial climate. The model is first spun up with a modern climatological surface forcing, which exhibits a multi-decadal oscillation, where the Southern Ocean is heated from below through the influx of warm and salty North Atlantic Deep Water, and the accumulation of heat induces intermittent convective overturning. Through the sensitivity experiments, we explore and illustrate the rich and complex behavior of the Antarctic ventilation and its response to the northern sinking, the surface wind stress, and the global mean temperature. When the northern sinking is weakened by a freshwater perturbation, the intermittent convection events are suppressed as the heat source is reduced. When the atmospheric temperature is lowered uniformly, the Antarctic seaice extent increases and the southern overturning weakens on centennial timescales. However, the convective overturning rebounds on the millennial timescale if the northern sinking is active. We will discuss implications of our results to the deep ventilation of the Southern Ocean and its impact on the ocean carbon storage.

  10. Noninvasive ventilation and obstructive lung diseases

    Microsoft Academic Search

    A. Cuvelier; J. F. Muir

    2001-01-01

    The key role of noninvasive positive pressure ventilation (NPPV) is well documented in chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF) since it may avoid endotrachal intubation in w50% of cases when used as the initial treatment. However, currently only minimal data is available to assess usefulness of NPPV in COPD patients on a long-term basis. Even

  11. Noninvasive ventilation: a decade of progress

    Microsoft Academic Search

    M. Elliott; N. Ambrosino

    2002-01-01

    During the 1990s, noninvasive ventilation moved from being almost unknown outside a few specialist centres to becoming a cornerstone in the management of patients with respiratory failure. As with many advances in medicine, the basic idea is not new. Indeed, the technique is almost as old as mankind itself. In Genesis, Chapter 2, verse 7 it is stated that \\

  12. Noninvasive ventilation in acute exacerbations of COPD

    Microsoft Academic Search

    M. W. Elliott

    2005-01-01

    Noninvasive ventilation has been a major advance in the management of acute exacerbations of chronic obstructive pulmonary disease, reducing the need for endotracheal intubation, thereby reducing complications and hospital costs, as well as improving survival. It has been used in a variety of different clinical environments including the emergency room, on general wards, in intermediate respiratory care units and in

  13. Endotracheal DNase for atelectasis in ventilated neonates

    Microsoft Academic Search

    R MacKinnon; K I Wheeler; J Sokol

    2011-01-01

    Management of atelectasis and lung collapse in ventilated neonates remains a common challenge in the neonatal intensive care unit. Recombinant human DNase (rhDNase) is an established treatment of atelectasis in cystic fibrosis and its use is also reported in the management of asthma, respiratory syncitial virus bronchiolitis and bronchiectasis to liquefy sputum and aid its clearance from the lungs. We

  14. Studies of imbalance difference theory in modeling conversion between differential mode and common mode signals

    NASA Astrophysics Data System (ADS)

    Niu, Li

    This dissertation describes three related studies regarding the imbalance difference theory in modeling the conversion between differential mode and common mode/antenna mode signals. The topics covered are: rigorous derivation of imbalance difference theory for modeling radiated emission problems, modeling the conversion between differential mode and common mode propagation in transmission lines, and modeling the loading impedance on differential mode signals due to radiated emissions. The imbalance difference theory describes a method for calculating the coupling between differential mode signals and common mode signals due to changes in electrical balance on a transmission line. It provides both physical insight and a simple technique for modeling the conversions between the two modes. The first chapter presents a rigorous derivation of imbalance difference theory for modeling radiated emission problems. Although the theory has been successfully used to model a wide variety of important EMC problems over the past, it has not been rigorously derived. The derivation carefully defines the important quantities and demonstrates that imbalance difference calculations are exact provided that the differential-mode propagation is TEM and the current division factor, h, represents the actual ratio of currents on the two transmission line conductors excited by a common-mode source. This chapter also discusses the acquisition of the current division factor from 2D calculations of the cross-section of the transmission line. The second chapter provides a rigorous development of the imbalance difference theory for three-conductor transmission lines where both the differential mode and common mode exhibit TEM propagation. It also derives expressions for the mode conversion impedances, which account for the energy converted from one mode to the other. They are essential for modeling the conversion between the two modes when they are strongly coupled. The third chapter introduces conversion impedance to the existing imbalance difference theory model for modeling radiated emission problems, so that when the coupling between differential mode and antenna mode are strong, the imbalance difference theory can more accurately estimate the antenna mode current. All three papers are about confirming, enriching and expanding the imbalance difference theory. The first chapter focuses on the rigorous derivation of theory for its most common application, radiated emission problems. The second chapter expands the theory to multi-conductor transmission line structure when the two modes are strongly coupled. The last chapter introduces conversion impedance to the theory in modeling radiated emission problems and improves the accuracy of the model at resonant frequencies.

  15. Perfusion redistribution after a pulmonary-embolism-like event with contrast enhanced EIT.

    PubMed

    Nguyen, D T; Bhaskaran, A; Chik, W; Barry, M A; Pouliopoulos, J; Kosobrodov, R; Jin, C; Oh, T I; Thiagalingam, A; McEwan, A L

    2015-06-01

    Recent studies showed that regional pulmonary perfusion can be reliably estimated using electrical impedance tomography (EIT) with the aid of hypertonic saline based contrast enhancement. Building on these successful studies, we studied contrast EIT for pulmonary perfusion defect caused by an artificially induced pulmonary embolism (PE) in a large ovine model (N = 8, 78 ± 7.8 kg). Furthermore, the efficacy of a less invasive contrast bolus of 0.77 ml kg(-1) of NaCl 3% was compared with a more concentrated bolus of 0.13 ml kg(-1) of NaCl 20%. Prior to the injection of each contrast bolus injection, ventilation was turned off to provide a total of 40 to 45 s of apnoea. Each bolus of impedance contrast was injected through a catheter into the right atrium. Pulmonary embolisation was performed by balloon occlusion of part of the right branch of the pulmonary trunk. Four parameters representing the kinetics of the contrast dilution in the lung were evaluated for statistical differences between baseline and PE, including peak value, maximum uptake, maximum washout and area under the curve of the averaged contrast dilution curve in each lung. Furthermore, the right lung to left lung (R2L) ratio of each the aforementioned parameters were assessed. While all of the R2L ratios yielded significantly different means between baseline and PE, it can be concluded that the R2L ratios of area under the curve and peak value of the averaged contrast dilution curve are the most promising and reliable in assessing PE. It was also found that the efficacy of the two types of impedance contrasts were not significantly different in distinguishing PE from baseline in our model. PMID:26006739

  16. Another brick in the wall of needs for invasive ventilation?

    PubMed Central

    2014-01-01

    Ventilator-induced lung injury and ventilator-induced diaphragmatic dysfunction are major complications in mechanically ventilated patients with acute respiratory failure. Invasive ventilation adds a further burden by increasing the risk of infections. An approach that protects both lung and diaphragm is pivotal. Mirabella and colleagues compared conventional controlled ventilation with a mode that combines several potentially lung-protective properties - non-invasively applied neurally adjusted ventilatory assist - in an animal experiment. This approach seemed to be as effective but potentially more lung-protective. Although the experimental setup and results cannot be translated directly to the clinical setting, they should motivate us to further study this innovative approach. PMID:25029382

  17. SY Tank Farm ventilation isolation option risk assessment report

    SciTech Connect

    Powers, T.B.; Morales, S.D.

    1994-03-01

    The safety of the 241-SY Tank Farm ventilation system has been under extensive scrutiny due to safety concerns associated with tank 101-SY. Hydrogen and other gases are generated and trapped in the waste below the liquid surface. Periodically, these gases are released into the dome space and vented through the exhaust system. This attention to the ventilation system has resulted in the development of several alternative ventilation system designs. The ventilation system provides the primary means of mitigation of accidents associated with flammable gases. This report provides an assessment of various alternatives ventilation system designs.

  18. Exercise-induced pulmonary perfusion redistribution in heaves.

    PubMed

    Harmegnies, N F; Duvivier, D H; Vandenput, S N; Art, T; Lekeux, P M; Votion, D M

    2002-09-01

    This study aimed to compare exercise-induced pulmonary perfusion redistribution in healthy vs. 'heavey' horses using scintigraphy, a minimally invasive technique. Six healthy (A) and 5 'heavey' horses in remission (B(I)) and during clinical signs of disease (B(II)) were investigated. Dimensions of the exercising pulmonary perfusion (QE) images were expressed in percent of the resting perfusion (QR) images. Computed QE to QR ratios (QE/QR) images enabled the definition of the region more perfused at exercise than at rest (R1). In all groups, exercise induced a major enlargement of the Q image but a larger increase of the lung height was found in 'heavey' horses. Compared to A, 'heavey' horses showed a larger R1 region with a significantly higher QE/QR. Location of R1 pointed out the dorsal lung region as a major site of pulmonary perfusion redistribution for all groups. This work demonstrated (1) the feasibility of using scintigraphy for studying exercise-induced pulmonary perfusion redistribution; (2) perfusion redistribution to the dorsal lung with exercise and (3) an intensified redistribution in 'heavey' horses, either clinically affected or not. PMID:12405737

  19. Hydrogels for Engineering of Perfusable Vascular Networks.

    PubMed

    Liu, Juan; Zheng, Huaiyuan; Poh, Patrina S P; Machens, Hans-Günther; Schilling, Arndt F

    2015-01-01

    Hydrogels are commonly used biomaterials for tissue engineering. With their high-water content, good biocompatibility and biodegradability they resemble the natural extracellular environment and have been widely used as scaffolds for 3D cell culture and studies of cell biology. The possible size of such hydrogel constructs with embedded cells is limited by the cellular demand for oxygen and nutrients. For the fabrication of large and complex tissue constructs, vascular structures become necessary within the hydrogels to supply the encapsulated cells. In this review, we discuss the types of hydrogels that are currently used for the fabrication of constructs with embedded vascular networks, the key properties of hydrogels needed for this purpose and current techniques to engineer perfusable vascular structures into these hydrogels. We then discuss directions for future research aimed at engineering of vascularized tissue for implantation. PMID:26184185

  20. Cerebral Perfusion Affects the Risk of Ischemia during Carotid Artery Stenting

    Microsoft Academic Search

    Lisa M. Jongen; Jeroen Hendrikse; Frans L. Moll; Willem P. T. M. Mali; H. Bart van der Worp

    2010-01-01

    Background: Patients with impaired perfusion in the hemisphere ipsilateral to a stenotic internal carotid artery may have a higher risk of cerebral ischemic complications than those with normal perfusion. We therefore studied whether the occurrence of new ischemic lesions after carotid artery stenting is related to cerebral perfusion. Methods: In 45 patients with symptomatic carotid artery stenosis, CT perfusion and

  1. Effort-reward imbalance, overcommitment, and psychological distress in Canadian police officers.

    PubMed

    Janzen, B L; Muhajarine, Nazeem; Zhu, Tong; Kelly, I W

    2007-04-01

    The purpose of the present study was to examine the relationship among Effort, Reward, and Overcommitment dimensions of Siegrist's Effort-Reward Imbalance Model and Psychological Distress in a sample of 78 Canadian police officers. Ages of respondents ranged between 24 and 56 years (M=36.1, SD=8.0). 30% of respondents had been in policing for 16 years or more, 24% between 6 and 15 years, and 44% for 5 years or less. Ordinary least-squares regression was used to evaluate the relationship between the independent and dependent variables. After adjusting for age, sex, education, and marital status, higher levels of Effort-Reward Imbalance and Overcommitment were associated with greater Psychological Distress. Present findings support the utility of the model in this particular occupational group and add to the increasing literature suggesting association of Effort-Reward Imbalance, Overcommitment, and reduced mental health. PMID:17564229

  2. New Fuzzy Support Vector Machine for the Class Imbalance Problem in Medical Datasets Classification

    PubMed Central

    Ni, Tongguang; Wang, Hongyuan

    2014-01-01

    In medical datasets classification, support vector machine (SVM) is considered to be one of the most successful methods. However, most of the real-world medical datasets usually contain some outliers/noise and data often have class imbalance problems. In this paper, a fuzzy support machine (FSVM) for the class imbalance problem (called FSVM-CIP) is presented, which can be seen as a modified class of FSVM by extending manifold regularization and assigning two misclassification costs for two classes. The proposed FSVM-CIP can be used to handle the class imbalance problem in the presence of outliers/noise, and enhance the locality maximum margin. Five real-world medical datasets, breast, heart, hepatitis, BUPA liver, and pima diabetes, from the UCI medical database are employed to illustrate the method presented in this paper. Experimental results on these datasets show the outperformed or comparable effectiveness of FSVM-CIP. PMID:24790571

  3. Investigation on Residual Swirl and Flue Gas Imbalance in Large Tangentially Fired Boiler

    NASA Astrophysics Data System (ADS)

    Lee, Yan-Peng; Xu, Jin-Yuan; Zhang, Qiang; Gu, Fan; Xu, Yi-Qian

    There exists the serious problem of flue gas imbalance at the entry of horizontal gas-pass in many large tangentially fired utility boilers used presently in China. In this paper, the experimental and computational investigations on residual swirl and flue gas imbalance are carried out based on an isothermal model of 600 MW tangentially fired boiler. The Porosity method and the improved non-uniform QUICK scheme are presented in 3-D numerical simulation in order to simulate the platen superheater correctly and reduce the pseudo-diffusion effectively. The numerical results agree well with the experiment. The calculated results of flow field in furnace, diameter of actual tangential circle, the distribution of swirling intensity along height of furnace and the effects of the structures of nose and the platen superheater on residual swirl and velocity deviation are presented. The forming cause and influencing factors of flue gas imbalance are discussed. Meanwhile, the means to diminish the deviation are introduced.

  4. Distinct evolutionary mechanisms for genomic imbalances in high-risk and low-risk neuroblastomas

    PubMed Central

    Gisselsson, David; Lundberg, Gisela; Øra, Ingrid; Höglund, Mattias

    2007-01-01

    Background Neuroblastoma (NB) is the most common extracranial solid tumour of childhood. Several genomic imbalances correlate to prognosis in NB, with structural rearrangements, including gene amplification, in a near-diploid setting typically signifying high-risk tumours and numerical changes in a near-triploid setting signifying low-risk tumours. Little is known about the temporal sequence in which these imbalances occur during the carcinogenic process. Methods We have reconstructed the appearance of cytogenetic imbalances in 270 NBs by first grouping tumours and imbalances through principal component analysis and then using the number of imbalances in each tumour as an indicator of evolutionary progression. Results Tumours clustered in four sub-groups, dominated respectively by (1) gene amplification in double minute chromosomes and few other aberrations, (2) gene amplification and loss of 1p sequences, (3) loss of 1p and other structural aberrations including gain of 17q, and (4) whole-chromosome gains and losses. Temporal analysis showed that the structural changes in groups 1–3 were acquired in a step-wise fashion, with loss of 1p sequences and the emergence of double minute chromosomes as the earliest cytogenetic events. In contrast, the gains and losses of whole chromosomes in group 4 occurred through multiple simultaneous events leading to a near-triploid chromosome number. Conclusion The finding of different temporal patterns for the acquisition of genomic imbalances in high-risk and low-risk NBs lends strong support to the hypothesis that these tumours are biologically diverse entities, evolving through distinct genetic mechanisms. PMID:17897457

  5. Model experimental studies of eliminating gas imbalance by biasing superheater division panels

    SciTech Connect

    Zhenjin, Z.; Yongguang, L.; Song, L.; Delong, Z.

    1999-07-01

    Tangential firing system is widely used on utility boilers since it can burn various coals with a complete combustion. However, inherent gas imbalance on horizontal gas pass often brings about overheating and bursting of convection heating surface tubes, which affects boilers' safe and economic operation directly. Cold flow modeling experimental results of a 300 MW utility boiler show that biasing superheater division panels not only can eliminate gas imbalance effectively but also has no effect on furnace aerodynamics, which is salient to overcome heat deviation and convenient to retrofit for tangentially fired utility boilers.

  6. Magnetic fields of photosphere and interplanetary space: Imbalance between positive and negative polarities

    NASA Astrophysics Data System (ADS)

    Vernova, E. S.; Tyasto, M. I.; Baranov, D. G.

    2014-12-01

    Photospheric magnetic fields are studied in this work on the basis of synoptic maps from the Kitt Peak Observatory (1976-2003) and WSO (1976-2012). The imbalance between positive and negative fluxes is considered for strong magnetic fields in the sunspot zone. The imbalance sign coincides with the polar field sign in the Northern hemisphere; it depends on both the phase of the 11-year cycle and the solar cycle parity. These features of variation in the magnetic field can be explained by a strong quadrupole moment of the photospheric magnetic field, which is also seen in a change of the polarity of the interplanetary magnetic field.

  7. Experimental Investigation of Ventilation of a Surface Piercing Hydrofoil

    NASA Astrophysics Data System (ADS)

    Harwood, Casey; Miguel Montero, Francisco; Young, Yin Lu; Ceccio, Steven

    2013-11-01

    Bodies that pierce a liquid free-surface are prone to entrainment of atmospheric and/or vaporous gases. This process, called ventilation, can occur suddenly and violently, drastically altering hydrodynamic response. Experiments have been conducted at the free-surface towing-tank in the University of Michigan Marine Hydrodynamics Laboratory to investigate fully attached, partially ventilated, and fully ventilated flows around a canonical surface-piercing hydrofoil. The objectives of the work are: (i) to gain a broad and improved understanding of the physics of ventilation, (ii) to classify the physical mechanisms by which ventilation inception and washout may occur and quantify the conditions required for each mechanism and (iii) to quantify the effects of ventilation on global hydrodynamic responses, including the six force and moment components. Experimental data and high-speed video will be used to illustrate the impact of ventilation on hydrodynamic loads, pressures, and flow structures. The completion of this study is expected to contribute significantly toward a comprehensive understanding of ventilation physics, and toward an improved ability to design safe and controllable ventilated lifting surfaces for use in propulsion, energy harvesting, and turbomachinery. Bodies that pierce a liquid free-surface are prone to entrainment of atmospheric and/or vaporous gases. This process, called ventilation, can occur suddenly and violently, drastically altering hydrodynamic response. Experiments have been conducted at the free-surface towing-tank in the University of Michigan Marine Hydrodynamics Laboratory to investigate fully attached, partially ventilated, and fully ventilated flows around a canonical surface-piercing hydrofoil. The objectives of the work are: (i) to gain a broad and improved understanding of the physics of ventilation, (ii) to classify the physical mechanisms by which ventilation inception and washout may occur and quantify the conditions required for each mechanism and (iii) to quantify the effects of ventilation on global hydrodynamic responses, including the six force and moment components. Experimental data and high-speed video will be used to illustrate the impact of ventilation on hydrodynamic loads, pressures, and flow structures. The completion of this study is expected to contribute significantly toward a comprehensive understanding of ventilation physics, and toward an improved ability to design safe and controllable ventilated lifting surfaces for use in propulsion, energy harvesting, and turbomachinery. Supported by: The Office of Naval Research (ONR) (Grant No. N00014-09-1-1204); the National Research Foundation of Korea (NRF) (GCRC-SOP Grant No. 2012-0004783); the National Science Foundation Graduate Student Research Fellowship (Grant No. DGE 1256260).

  8. Noninvasive ventilation in acute respiratory failure.

    PubMed

    Mas, Arantxa; Masip, Josep

    2014-01-01

    After the institution of positive-pressure ventilation, the use of noninvasive ventilation (NIV) through an interface substantially increased. The first technique was continuous positive airway pressure; but, after the introduction of pressure support ventilation at the end of the 20th century, this became the main modality. Both techniques, and some others that have been recently introduced and which integrate some technological innovations, have extensively demonstrated a faster improvement of acute respiratory failure in different patient populations, avoiding endotracheal intubation and facilitating the release of conventional invasive mechanical ventilation. In acute settings, NIV is currently the first-line treatment for moderate-to-severe chronic obstructive pulmonary disease exacerbation as well as for acute cardiogenic pulmonary edema and should be considered in immunocompromised patients with acute respiratory insufficiency, in difficult weaning, and in the prevention of postextubation failure. Alternatively, it can also be used in the postoperative period and in cases of pneumonia and asthma or as a palliative treatment. NIV is currently used in a wide range of acute settings, such as critical care and emergency departments, hospital wards, palliative or pediatric units, and in pre-hospital care. It is also used as a home care therapy in patients with chronic pulmonary or sleep disorders. The appropriate selection of patients and the adaptation to the technique are the keys to success. This review essentially analyzes the evidence of benefits of NIV in different populations with acute respiratory failure and describes the main modalities, new devices, and some practical aspects of the use of this technique. PMID:25143721

  9. Noninvasive ventilation in acute respiratory failure

    PubMed Central

    Mas, Arantxa; Masip, Josep

    2014-01-01

    After the institution of positive-pressure ventilation, the use of noninvasive ventilation (NIV) through an interface substantially increased. The first technique was continuous positive airway pressure; but, after the introduction of pressure support ventilation at the end of the 20th century, this became the main modality. Both techniques, and some others that have been recently introduced and which integrate some technological innovations, have extensively demonstrated a faster improvement of acute respiratory failure in different patient populations, avoiding endotracheal intubation and facilitating the release of conventional invasive mechanical ventilation. In acute settings, NIV is currently the first-line treatment for moderate-to-severe chronic obstructive pulmonary disease exacerbation as well as for acute cardiogenic pulmonary edema and should be considered in immunocompromised patients with acute respiratory insufficiency, in difficult weaning, and in the prevention of postextubation failure. Alternatively, it can also be used in the postoperative period and in cases of pneumonia and asthma or as a palliative treatment. NIV is currently used in a wide range of acute settings, such as critical care and emergency departments, hospital wards, palliative or pediatric units, and in pre-hospital care. It is also used as a home care therapy in patients with chronic pulmonary or sleep disorders. The appropriate selection of patients and the adaptation to the technique are the keys to success. This review essentially analyzes the evidence of benefits of NIV in different populations with acute respiratory failure and describes the main modalities, new devices, and some practical aspects of the use of this technique. PMID:25143721

  10. The techniques used to sedate ventilated patients

    Microsoft Academic Search

    H. M. Merriman; Princess MargaretHospital

    1981-01-01

    A survey of sedation techniques for ventilated patients was performed by visiting 34 Intensive Care Units in Great Britain and Northern Ireland. The opiates in frequent use were phenoperidine (21 units-62% of units), papaveretum (11–32%) and morphine (9–26%). Many units used more than one opiate. Levorphanol, buprenorphine, pethidine, fentanyl and codeine were little used. Frequent use of diazepam was found

  11. Analysis of home support and ventilator malfunction in 1,211 ventilator-dependent patients.

    PubMed

    Chatwin, M; Heather, S; Hanak, A; Polkey, M I; Simonds, A K

    2010-02-01

    Risk management is an important aspect of home ventilation (HV). We examined the nature of calls to a home support helpline to identify patient/equipment problems and strategies to minimise risk for patients, healthcare teams and manufacturers. From 1,211 adult and paediatric patients with neuromuscular disease, chronic obstructive pulmonary disease or chest wall disease receiving HV, all calls to a dedicated respiratory support telephone hotline between January 1, 2006 and June 30, 2006 were analysed. 1,199 patients received noninvasive ventilation, 12 tracheostomy ventilation; 149 had two ventilators for 24-h ventilator dependency. There was a mean of 528 daytime calls per month and 14 calls a month at night. Following 188 calls, a home visit was performed; these identified a technical problem that could either be solved in the patient's home in 64% or required replacement or new parts in 22% of cases. In 25 calls in which no mechanical fault was identified, 13 patients were either found to be unwell or required hospital admission. Patients using HV have a substantial requirement for assistance, with most technical problems being resolved simply. Where no fault can be found during an equipment check, the patient themselves may be unwell and should receive early clinical evaluation. The patient may have mistaken clinical deterioration for an equipment problem. PMID:19643945

  12. Confined space ventilation by shipyard welders: observed use and effectiveness.

    PubMed

    Pouzou, Jane G; Warner, Chris; Neitzel, Richard L; Croteau, Gerry A; Yost, Michael G; Seixas, Noah S

    2015-01-01

    Shipbuilding involves intensive welding activities within enclosed and confined spaces, and although ventilation is commonly used in the industry, its use and effectiveness has not been adequately documented. Workers engaged in welding in enclosed or confined spaces in two shipyards were observed for their use of ventilation and monitored for their exposure to particulate matter. The type of ventilation in use, its placement and face velocity, the movement of air within the space, and other ventilation-related parameters were recorded, along with task characteristics such as the type of welding, the welder's position, and the configuration of the space. Mechanical ventilation was present in about two-thirds of the 65 welding scenarios observed, with exhaust ventilation used predominantly in one shipyard and supply blowers predominantly in the other. Welders were observed working in apparent dead-spaces within the room in 53% of the cases, even where ventilation was in use. Respiratory protection was common in the two shipyards, observed in use in 77 and 100% of the cases. Welding method, the proximity of the welder's head to the fume, and air mixing were found to be significantly associated with the welder's exposure, while other characteristics of dilution ventilation did not produce appreciable differences in exposure level. These parameters associated with exposure reduction can be assessed subjectively and are thus good candidates for training on effective ventilation use during hot work in confined spaces. Ventilation used in confined space welding is often inadequate for controlling exposure to welding fume. PMID:25245587

  13. The performance of Dräger Oxylog ventilators at simulated altitude.

    PubMed

    Flynn, J G; Singh, B

    2008-07-01

    Ventilated patients frequently require transport by air in a hypobaric environment. Previous studies have demonstrated significant changes in the performance of ventilators with changes in cabin pressure (altitude) but no studies have been published on the function of modem ventilators at altitude. This experiment set out to evaluate ventilatory parameters (tidal volume and respiratory rate) of three commonly used transport ventilators (the Dräger Oxylog 1000, 2000 and 3000) in a simulated hypobaric environment. Ventilators were assessed using either air-mix (60% oxygen) or 100% oxygen and tested against models simulating a normal lung, a low compliance (Acute Respiratory Distress Syndrome) lung and a high-resistance (asthma) lung. Ventilators were tested at a range of simulated altitudes between sea level and 3048 m. Over this range, tidal volume delivered by the Oxylog 1000 increased by 68% and respiratory rate decreased by 28%. Tidal volume delivered by the Oxylog 2000 ventilator increased by 29% over the same range of altitudes but there was no significant change in respiratory rate. Tidal volume and respiratory rate remained constant with the Oxylog 3000 over the same range of altitudes. Changes were consistent with each ventilator regardless of oxygen content or lung model. It is important that clinicians involved in critical care transport in a hypobaric environment are aware that individual ventilators perform differently at altitude and that they are aware of the characteristics of the particular ventilator that they are using. PMID:18714624

  14. Automated Determination of Arterial Input Function Areas in Perfusion Analysis 

    E-print Network

    Liu, Qun

    2013-04-04

    of perfusion studies requires the accurate determination of the arterial input function (AIF), which describes the delivery of intravascular tracers to tissues. Automating the process of finding the AIF can save operating time, remove the inter...

  15. Perfusion computed tomography to assist decision making for stroke thrombolysis.

    PubMed

    Bivard, Andrew; Levi, Christopher; Krishnamurthy, Venkatesh; McElduff, Patrick; Miteff, Ferdi; Spratt, Neil J; Bateman, Grant; Donnan, Geoffrey; Davis, Stephen; Parsons, Mark

    2015-07-01

    The use of perfusion imaging to guide selection of patients for stroke thrombolysis remains controversial because of lack of supportive phase three clinical trial evidence. We aimed to measure the outcomes for patients treated with intravenous recombinant tissue plasminogen activator (rtPA) at a comprehensive stroke care facility where perfusion computed tomography was routinely used for thrombolysis eligibility decision assistance. Our overall hypothesis was that patients with 'target' mismatch on perfusion computed tomography would have improved outcomes with rtPA. This was a prospective cohort study of consecutive ischaemic stroke patients who fulfilled standard clinical/non-contrast computed tomography eligibility criteria for treatment with intravenous rtPA, but for whom perfusion computed tomography was used to guide the final treatment decision. The 'real-time' perfusion computed tomography assessments were qualitative; a large perfusion computed tomography ischaemic core, or lack of significant perfusion lesion-core mismatch were considered relative exclusion criteria for thrombolysis. Specific volumetric perfusion computed tomography criteria were not used for the treatment decision. The primary analysis compared 3-month modified Rankin Scale in treated versus untreated patients after 'off-line' (post-treatment) quantitative volumetric perfusion computed tomography eligibility assessment based on presence or absence of 'target' perfusion lesion-core mismatch (mismatch ratio >1.8 and volume >15 ml, core <70 ml). In a second analysis, we compared outcomes of the perfusion computed tomography-selected rtPA-treated patients to an Australian historical cohort of non-contrast computed tomography-selected rtPA-treated patients. Of 635 patients with acute ischaemic stroke eligible for rtPA by standard criteria, thrombolysis was given to 366 patients, with 269 excluded based on visual real-time perfusion computed tomography assessment. After off-line quantitative perfusion computed tomography classification: 253 treated patients and 83 untreated patients had 'target' mismatch, 56 treated and 31 untreated patients had a large ischaemic core, and 57 treated and 155 untreated patients had no target mismatch. In the primary analysis, only in the target mismatch subgroup did rtPA-treated patients have significantly better outcomes (odds ratio for 3-month, modified Rankin Scale 0-2 = 13.8, P < 0.001). With respect to the perfusion computed tomography selected rtPA-treated patients (n = 366) versus the clinical/non-contrast computed tomography selected rtPA-treated patients (n = 396), the perfusion computed tomography selected group had higher adjusted odds of excellent outcome (modified Rankin Scale 0-1 odds ratio 1.59, P = 0.009) and lower mortality (odds ratio 0.56, P = 0.021). Although based on observational data sets, our analyses provide support for the hypothesis that perfusion computed tomography improves the identification of patients likely to respond to thrombolysis, and also those in whom natural history may be difficult to modify with treatment. PMID:25808369

  16. Myocardial Perfusion Spect Imaging in Dextrocardia: A Case Report

    PubMed Central

    Özdemir, Semra; Gazi, Emine

    2013-01-01

    The myocardial perfusion scintigraphy acquisition and analysis present some technical differences in the rare dextrocardia cases. Here we report a case of a 38 year-old woman with dextrocardia who had been applied myocardial perfusion scintigraphy. Presented case showed that the thoracic and abdominal organs had a mirror image with situs inversus totalis type dextrocardia. The incidence of coronary heart disease and life span of people with situs inversus totalis are the same as the normal population. So we may apply myocardial perfusion scintigraphy to this patient group. The current case is presented in order to remind the special applications of myocardial perfusion SPECT imaging in patients with dextrocardia. Conflict of interest:None declared. PMID:24003402

  17. Displaying perfusion MRI images as color intensity projections

    E-print Network

    Friso Hoefnagels; Keith S Cover; Ester Sanchez; Frank J. Lagerwaard

    2007-11-19

    Dynamic susceptibility-weighted contrast-enhanced (DSC) MRI or perfusion-MRI plays an important role in the non-invasive assessment of tumor vascularity. However, the large number of images provided by the method makes display and interpretation of the results challenging. Current practice is to display the perfusion information as relative cerebral blood volume maps (rCBV). Color intensity projections (CIPs) provides a simple, intuitive display of the perfusion-MRI data so that regional perfusion characteristics are intrinsically integrated into the anatomy structure the T2 images. The ease of use and quick calculation time of CIPs should allow it to be easily integrated into current analysis and interpretation pipelines.

  18. Development of a Perfusion Fed Bioreactor for Embryonic Stem

    E-print Network

    Zandstra, Peter W.

    Development of a Perfusion Fed Bioreactor for Embryonic Stem Cell-Derived Cardiomyocyte Generation. Embryonic stem (ES) cells may be a promising source for therapeutic applications, potentially providing design; stem cells; cardiomyocytes; oxygen; tissue engineering INTRODUCTION Adult cardiomyocytes

  19. Human males and females body thermoregulation: perfusion effect analysis.

    PubMed

    Acharya, Saraswati; Gurung, D B; Saxena, V P

    2014-10-01

    Skin temperature is a common physiological parameter that reflects thermal responses. Blood perfusion is an important part of the physiological processes that the human body undergoes in order to maintain homeostasis. This study focuses on the effect of perfusion on the temperature distribution in human males and females body in different thermal environment. The study has been carried out for one dimensional steady cases using finite element method. The input parameter of the model is the blood perfusion or volumetric flow rate within the tissue. The appropriate physical and physiological parameters together with suitable boundary conditions that affect the heat regulations have been incorporated in the model. The study is to have a better understanding that how does thermoregulation change in human males and females skin layered due to perfusion. PMID:25436948

  20. Artificial ventilation of the lungs for emergencies.

    PubMed

    Darowski, M; Englisz, M

    2000-01-01

    The necessity for extraordinary ventilatory support may appear in different places all over the world in cases of a massive disaster (industrial or natural), connected with gas poisoning on a huge scale. Hospitals equipped with limited number of respirators, adequate for peacetime activity, are not able to meet suddenly multiplied requirements for ventilatory support. This paper describes a preliminary study to develop a convenient, reliable method of performing artificial ventilation of at least two patient by means of only one ventilator. We developed a unique, new control system (patent pending) which, when placed between a respirator and endotracheal tubes of the patients, divides the total tidal volume between the patients' lungs and controls pressures at their airways. A special arrangement of valves in the control system enables us to separate inspiratory and expiratory paths for each patient and to avoid cross-infection. The model study performed, according to ISO standards, on mechanical test lungs has shown that the proposed control system enables us to adjust ventilatory parameters at desired values, when lung compliance or respiratory airway resistance differ. The proposed one-source artificial ventilation is a simple solution to provide ventilatory support when the number of patients is greater than the number of respirators that are available. PMID:11014679

  1. Long-term mechanical ventilation and nutrition.

    PubMed

    Ambrosino, Nicolino; Clini, Enrico

    2004-05-01

    Mechanical ventilation (MV) in chronic situations is commonly used, either delivered invasively or by means of non-invasive interfaces, to control hypoventilation in patients with chest wall, neuromuscular or obstructive lung diseases (either in adulthood or childhood). The global prevalence of ventilator-assisted individuals (VAI) in Europe ranges from 2 to 30 per 100000 population according to different countries. Nutrition is a common problem to face with in patients with chronic respiratory diseases: nonetheless, it is a key component in the long-term management of underweight COPD patients whose muscular disfunction may rapidly turn to peripheral muscle waste. Since long-term mechanical ventilation (LTMV) is usually prescribed in end-stage respiratory diseases with poor nutritional status, nutrition and dietary intake related problems need to be carefully assessed and corrected in these patients. This paper aims to review the most recent innovations in the field of nutritional status and food intake-related problems of VAI (both in adulthood and in childhood). PMID:15139570

  2. Acute applications of noninvasive positive pressure ventilation.

    PubMed

    Liesching, Timothy; Kwok, Henry; Hill, Nicholas S

    2003-08-01

    Noninvasive positive-pressure ventilation (NPPV) has been used increasingly to treat acute respiratory failure (ARF). The best indications for its use are ARF in patients with COPD exacerbations, acute pulmonary edema, and immunocompromised states. For these indications, multiple controlled trials have demonstrated that therapy with NPPV avoids intubation and, in the case of COPD and immunocompromised patients, reduces mortality as well. NPPV is used to treat patients with numerous other forms of ARF, but the evidence is not as strong for its use in those cases, and patients must be selected carefully. The best candidates for NPPV are able to protect their airway, are cooperative, and are otherwise medically stable. Success is optimized when a skilled team applies a well-fitted, comfortable interface. Ventilator settings should be adjusted to reduce respiratory distress while avoiding excessive discomfort, patient-ventilator synchrony should be optimized, and adequate oxygenation should be assured. The appropriate application of NPPV in the acute care setting should lead to improved patient outcomes and more efficient resource utilization. PMID:12907562

  3. Pulmonary ventilation (V) and perfusion (Q) scintigraphy in the evaluation of endobronchial neoplasm following laser photoradiation therapy

    SciTech Connect

    Yamauchi, D.; Colletti, P.; Beck, S.; Hoffman, S.; Balchum, O.J.; Siegel, M.E.

    1985-05-01

    Laser photoradiation therapy (PRT) following tissue sensitization by hematoporphyrin has become increasingly important as a nonsurgical treatment of endobronchial (EB) cancer. The authors utilized V and Q scans to evaluate the physiologic response of these neoplasms to PRT. Twenty-three sets of V (Kr-81m and Xe-133) and Q (Tc-99m MAA) scans were performed in 22 patients (pts) (15M, 7F, ages 34-78) with bronchoscopically proven EB neoplasms immediately prior to and immediately post PRT. These studies were correlated with pre- and post-PRT bronchoscopies. Pre-PRT, 21/23 (91%) V (Kr-81m) scans, 21/23 (91%) Q (Tc-99m MAA) scans, and 19/21 (90%) V (Xe-133) scans revealed abnormalities distal to 29 EB lesions. Post-PRT bronchoscopy revealed 16/29 (55%) lesions with significant improvement in degree of obstruction, 12/29 (41%) with essentially no change, and 1/29 (3%) with significant worsening. Good correlation between change on V-Q scan and change on bronchoscopy existed in 19/29 (66%) EB lesions. Evaluated as a separate criterion, Xe-133 V identified 4 additional lesions which improved bronchoscopically. This increased correlation between scan and bronchoscopy to 23/29 (79%). Of the 9 EB lesions in which both V and Q improved, 8/9 also had significant bronchoscopic improvement. In only 1 case did a patient's EB lesion improve bronchoscopically while her V-Q studies worsened. V and Q scans are sensitive indicators of EB neoplasm (90%+), provide a physiologic monitor of EB lesion response to PRT and may supplement the anatomic findings of bronchoscopy in the evaluation of pts with EB cancer.

  4. Synthesis of Fibronectin by the Isolated Perfused Rat Liver

    Microsoft Academic Search

    Catherine D. Cimino

    2010-01-01

    The major site(s) of synthesis of plasma fibronectin is unknown. Using the isolated perfused rat liver and anti-rat fibronectin antiserum. we have measured net hepatic syn- thesis of fibronectin during 1 0-hr perfusion periods. We calculated the circulating plasma fibronectin pool of a 1 95-g rat with body surface area of300 sq cm to be 3.3 mg; net hepatic synthesis

  5. Echo-Planar Perfusion MR of Moyamoya Disease

    Microsoft Academic Search

    Kazuhiro Tsuchiya; Sayuki Inaoka; Yoshiyuki Mizutani; Junichi Hachiya

    1998-01-01

    PURPOSE: Our goal was to assess the value of perfusion MR imaging by using a single-shot echo-planar technique to evaluate the hemodynamics of moyamoya disease. METHODS: We performed echo-planar perfusion studies in 19 patients with a 1.5-T unit, using a free-induction-decay echo-planar sequence for 14 examinations and a turbo-gradient- spin-echo echo-planar sequence for five examinations. After a bolus injection of

  6. Perfusion of nonventilated lung: failure of hypoxic vasoconstriction

    SciTech Connect

    Sostman, H.D.; Neumann, R.D.; Gottschalk, A.; Greenspan, R.H.

    1983-07-01

    Alveolar hypoxia is a well established cause of regional vasoconstriction such that nonventilated segments are not perfused. The paradoxical situation of retained perfusion of nonventilated lung has seldom been discussed. Three clinical examples are illustrated. In each case coexistent chronic obstructive lung disease may have contributed to this unexpected finding by reducing pulmonary vascular capacity such that blood flow diversion from hypoxic segments was not possible.

  7. Basic study on hepatic resection under partial perfusion cooling

    Microsoft Academic Search

    Isao Hamamoto; Mohammad Akram Hossain; Setsuo Okada; Hisao Wakabayashi; Takashi Maeba; Satoshi Tanaka

    1994-01-01

    To improve liver quality after reperfusion following partial hepatectomy under total or partial cooling of the liver (HPC), a new perfusion solution containing 100 mM l-histidine (KM solution) was developed. The livers of Lewis rats were removed and perfused for 2 hours at 20°C with lactated Ringer's (LR) solution (group A) or the KM solution (group B). They were reperfused

  8. Value of multidetector computed tomography evaluation of myocardial perfusion in the assessment of ischemic heart disease: comparison with nuclear perfusion imaging

    Microsoft Academic Search

    Nadjia Kachenoura; Joseph A. Lodato; Tamar Gaspar; Dianna M. E. Bardo; Barbara Newby; Sarah Gips; Nathan Peled; Roberto M. Lang; Victor Mor-Avi

    2009-01-01

    MDCT-derived myocardial perfusion has not yet been validated against accepted standards. We developed a technique for quantification\\u000a of myocardial perfusion from MDCT images and studied its diagnostic value against SPECT myocardial perfusion imaging (MPI).\\u000a Ninety-eight patients were studied. Abnormal perfusion was detected by comparing normalized segmental x-ray attenuation against\\u000a values obtained in 20 control subjects. Disagreement with resting MPI was

  9. Nifedipine improves blood flow and oxygen supply, but not steady-state oxygenation of tumours in perfusion pressure-controlled isolated limb perfusion

    Microsoft Academic Search

    O Thews; M Hummel; D K Kelleher; B Lecher; P Vaupel

    2002-01-01

    Isolated limb perfusion allows the direct application of therapeutic agents to a tumour-bearing extremity. The present study investigated whether the dihydropyridine-type Ca2+-channel blocker nifedipine could improve blood flow and oxygenation status of experimental tumours during isolated limb perfusion. Perfusion was performed by cannulation of the femoral artery and vein in rats bearing DS-sarcoma on the hind foot dorsum. Perfusion rate

  10. Analysis of the effect of charge imbalance on the static and dynamic characteristics of the super junction MOSFET

    Microsoft Academic Search

    P. M. Shenoy; A. Bhalla; G. M. Dolny

    1999-01-01

    In this paper, a novel device called the super junction MOSFET is analyzed using analytical modeling and numerical simulations. The effect of charge imbalance between the N and P pillars on the static and dynamic characteristics of the device is studied in detail. Simulations predict that this device is highly sensitive to charge imbalance if designed for optimum on-resistance. The

  11. Different Probe Combinations for Assessment of Postzygotic Chromosomal Imbalances in Human Embryos

    Microsoft Academic Search

    Magdalena Bielanska; Seang Lin Tan; Asangla Ao

    2002-01-01

    Purpose: We compared three different probe combinations for detection of postzygotic mosaic imbalances in human preimplantation embryos. Methods: Two hundred and two spare cleavage stage embryos were hybridized with fluorescently labelled DNA probe mixtures specific to chromosomes X, Y, 18 (N = 67), chromosomes 2, 7, 18 (N = 71), or chromosomes 13, 16, 18, 21, 22 (N = 64).

  12. Spontaneous chiral symmetry breaking and the chiral magnetic effect for interacting Dirac fermions with chiral imbalance

    NASA Astrophysics Data System (ADS)

    Buividovich, P. V.

    2014-12-01

    We report on a mean-field study of spontaneous breaking of chiral symmetry for Dirac fermions with contact interactions in the presence of chiral imbalance, which is modeled by nonzero chiral chemical potential. We point out that chiral imbalance lowers the vacuum energy of Dirac fermions, which leads to the increase of the renormalized chiral chemical potential upon chiral symmetry breaking. The critical coupling strength for the transition to the broken phase is slightly lowered as the chiral chemical potential is increased, and the transition itself becomes milder. Furthermore, we study the chiral magnetic conductivity in different phases and find that it grows both in the perturbative weak-coupling regime and in the strongly coupled phase with broken chiral symmetry. In the strong coupling regime the chiral magnetic effect is saturated by vectorlike bound states (vector mesons) with mixed transverse polarizations. General pattern of meson mixing in the presence of chiral imbalance is also considered. We discuss the relevance of our study for Weyl semimetals and strongly interacting QCD matter. Finally, we comment on the ambiguity of the regularization of the vacuum energy of Dirac fermions in the presence of chirality imbalance.

  13. Autonomic imbalance is associated with reduced facial recognition in somatoform disorders

    Microsoft Academic Search

    Olga Pollatos; Beate M. Herbert; Sarah Wankner; Anja Dietel; Cornelia Wachsmuth; Peter Henningsen; Martin Sack

    2011-01-01

    ObjectivesSomatoform disorders are characterized by the presence of multiple somatic symptoms. While the accuracy of perceiving bodily signal (interoceptive awareness) is only sparely investigated in somatoform disorders, recent research has associated autonomic imbalance with cognitive and emotional difficulties in stress-related diseases. This study aimed to investigate how sympathovagal reactivity interacts with performance in recognizing emotions in faces (facial recognition task).

  14. Evidence for metabolic imbalance of vitamin A2 in wild fish chronically exposed to metals

    E-print Network

    Bernatchez, Louis

    Evidence for metabolic imbalance of vitamin A2 in wild fish chronically exposed to metals Michel A was observed. These results suggest that the enzymes and the binding proteins involved in vitamin A homeostasis are inhibited by the presence of Cd. Alternatively, the increase in tissue vitamin A (antioxidant) levels could

  15. Force-velocity profile: imbalance determination and effect on lower limb ballistic performance.

    PubMed

    Samozino, P; Edouard, P; Sangnier, S; Brughelli, M; Gimenez, P; Morin, J-B

    2014-06-01

    This study sought to lend experimental support to the theoretical influence of force-velocity (F-v) mechanical profile on jumping performance independently from the effect of maximal power output (P max ). 48 high-level athletes (soccer players, sprinters, rugby players) performed maximal squat jumps with additional loads from 0 to 100% of body mass. During each jump, mean force, velocity and power output were obtained using a simple computation method based on flight time, and then used to determine individual linear F-v relationships and P max values. Actual and optimal F-v profiles were computed for each subject to quantify mechanical F-v imbalance. A multiple regression analysis showed, with a high-adjustment quality (r²=0.931, P<0.001, SEE=0.015?m), significant contributions of P max , F-v imbalance and lower limb extension range (h PO ) to explain interindividual differences in jumping performance (P<0.001) with positive regression coefficients for P max and h PO and a negative one for F-v imbalance. This experimentally supports that ballistic performance depends, in addition to P max , on the F-v profile of lower limbs. This adds support to the actual existence of an individual optimal F-v profile that maximizes jumping performance, a F-v imbalance being associated to a lower performance. These results have potential strong applications in the field of strength and conditioning. PMID:24227123

  16. Microarray comparative genomic hybridization detection of chromosomal imbalances in uterine cervix carcinoma

    Microsoft Academic Search

    Alfredo Hidalgo; Michael Baudis; Iver Petersen; Hugo Arreola; Patricia Piña; Guelaguetza Vázquez-Ortiz; Dulce Hernández; José González; Minerva Lazos; Ricardo López; Carlos Pérez; José García; Karla Vázquez; Brenda Alatorre; Mauricio Salcedo

    2005-01-01

    BACKGROUND: Chromosomal Comparative Genomic Hybridization (CGH) has been applied to all stages of cervical carcinoma progression, defining a specific pattern of chromosomal imbalances in this tumor. However, given its limited spatial resolution, chromosomal CGH has offered only general information regarding the possible genetic targets of DNA copy number changes. METHODS: In order to further define specific DNA copy number changes

  17. A weighted rough set based method developed for class imbalance learning

    Microsoft Academic Search

    Jinfu Liu; Qinghua Hu; Daren Yu

    2008-01-01

    In this paper, we introduce weights into Pawlak rough set model to balance the class distribution of a data set and develop a weighted rough set based method to deal with the class imbalance problem. In order to develop the weighted rough set based method, we design first a weighted attribute reduction algorithm by introducing and extending Guiasu weighted entropy

  18. New Algorithms for Address Decoder Delay Faults and Bit Line Imbalance Faults

    Microsoft Academic Search

    A. J. Van De Goor; Said Hamdioui; Georgi Nedeltchev Gaydadjiev; Zaid Al-ars

    2009-01-01

    Due to the rapid decrease of technology feature size speed related faults, such as Address Decoder Delay Faults (ADDFs), are becoming very important. In addition, increased leakage currents demand for improved tests for Bit Line Imbalance Faults (BLIFs)(caused by memory cell pass transistor leakage). This paper contributes to new and improved algorithms for detecting these faults. First it provides an

  19. Earth's Energy Imbalance and Implications James Hansen, Makiko Sato, Pushker Kharecha

    E-print Network

    Hansen, James E.

    1 Earth's Energy Imbalance and Implications James Hansen, Makiko Sato, Pushker Kharecha NASA Goddard Institute for Space Studies, New York, NY 10025, USA Columbia University Earth Institute, New York, hosted by Ifremer, Brest, France Abstract. Improving observations of ocean heat content show that Earth

  20. Earth's Energy Imbalance and Implications James Hansen, Makiko Sato, Pushker Kharecha

    E-print Network

    Hansen, James E.

    1 Earth's Energy Imbalance and Implications James Hansen, Makiko Sato, Pushker Kharecha NASA Goddard Institute for Space Studies, New York, NY 10025, USA Columbia University Earth Institute, New York that Earth is absorbing more energy from the sun than it is radiating to space as heat, even during

  1. Imbalance Identification of an OverHung Rotor Based on the Accelerating Response Data

    Microsoft Academic Search

    J. P. Huang; X. M. Ren

    2009-01-01

    Based on the transfer matrix method, the transient equations of motion for an over-hung rotor are established. Then, the Newmark integral method is employed to solve the model equations numerically. An imbalance identification method of the over-hung rotor based on the accelerating response data has been presented after investigating the operating characteristics of the rotor. In this new method, only

  2. Can spatial heterogeneity explain the perceived imbalance in Lake Superior's carbon budget? A model study

    E-print Network

    Wisconsin at Madison, University of

    is the largest lake in the world by surface area, containing 10% of the world's surface freshwater. Yet, little couple a hydrodynamic model of Lake Superior to an ecosystem model to understand the seasonal cycleCan spatial heterogeneity explain the perceived imbalance in Lake Superior's carbon budget? A model

  3. Combating Imbalance in Network Intrusion Datasets David A Cieslak, Nitesh V Chawla, Aaron Striegel

    E-print Network

    Chawla, Nitesh V.

    1 Combating Imbalance in Network Intrusion Datasets David A Cieslak, Nitesh V Chawla, Aaron Striegel Abstract-- An approach to combating network intrusion is the development of systems applying machine learning and data min- ing techniques. Many IDS (Intrusion Detection Systems) suffer from a high

  4. Insight into human sex ratio imbalance: the more boys born, the more infertile men

    Microsoft Academic Search

    Hanhua Cheng; Xuan Shang; Yan He; Tao Zhang; Ya-Ping Zhang; Rongjia Zhou

    2007-01-01

    This study investigated, through large-scale statistical analysis of the global population, whether the human sex ratio is skewing worldwide, and if so, why and how it shifts, and the impact of any shift on human reproduction. A significant imbalance of the sex ratio was observed in the whole human population, resulting in a vicious circle where the more boys born,

  5. Profound imbalance of pro-fibrinolytic and anti-fibrinolytic factors (tissue plasminogen activator and plasminogen

    E-print Network

    Mosher, Deane F.

    Profound imbalance of pro-fibrinolytic and anti-fibrinolytic factors (tissue plasminogen activator) activity and high t-PA antigen. Treatment with oral anti- fibrinolytic agents prevented further bleeding-operatively, the patient did not require oral anti-fibrinolytic agents, and there were no significant bleeding events

  6. Lipid-Induced Peroxidation in the Intestine Is Involved in Glucose Homeostasis Imbalance in Mice

    E-print Network

    Paris-Sud XI, Université de

    Lipid-Induced Peroxidation in the Intestine Is Involved in Glucose Homeostasis Imbalance in Mice in the dysfunction of glucose homeostasis. The study aimed at comparing the effect of Medialipid (ML) overload and normalized glucose homeostasis and vagus nerve activity. Conclusions/Significance: Lipid overload within

  7. A Monte Carlo investigation of thrust imbalance of solid rocket motor pairs

    NASA Technical Reports Server (NTRS)

    Sforzini, R. H.; Foster, W. A., Jr.; Johnson, J. S., Jr.

    1974-01-01

    A technique is described for theoretical, statistical evaluation of the thrust imbalance of pairs of solid-propellant rocket motors (SRMs) firing in parallel. Sets of the significant variables, determined as a part of the research, are selected using a random sampling technique and the imbalance calculated for a large number of motor pairs. The performance model is upgraded to include the effects of statistical variations in the ovality and alignment of the motor case and mandrel. Effects of cross-correlations of variables are minimized by selecting for the most part completely independent input variables, over forty in number. The imbalance is evaluated in terms of six time - varying parameters as well as eleven single valued ones which themselves are subject to statistical analysis. A sample study of the thrust imbalance of 50 pairs of 146 in. dia. SRMs of the type to be used on the space shuttle is presented. The FORTRAN IV computer program of the analysis and complete instructions for its use are included. Performance computation time for one pair of SRMs is approximately 35 seconds on the IBM 370/155 using the FORTRAN H compiler.

  8. Socio-Cultural Imbalances in AIED Research: Investigations, Implications and Opportunities

    ERIC Educational Resources Information Center

    Blanchard, Emmanuel G.

    2015-01-01

    This paper investigates international representations in the Artificial Intelligence in Education (AIED) research field. Its methodological and theoretical groundings are inspired by Arnett (2008) and Henrich et al. (2010a) who addressed the same issue in psychology, and respectively a) discovered massive imbalances in representation in top-tier…

  9. Allelic Imbalance Is a Prevalent and Tissue-Specific Feature of the Mouse Transcriptome.

    PubMed

    Pinter, Stefan F; Colognori, David; Beliveau, Brian J; Sadreyev, Ruslan I; Payer, Bernhard; Yildirim, Eda; Wu, Chao-Ting; Lee, Jeannie T

    2015-06-01

    In mammals, several classes of monoallelic genes have been identified, including those subject to X-chromosome inactivation (XCI), genomic imprinting, and random monoallelic expression (RMAE). However, the extent to which these epigenetic phenomena are influenced by underlying genetic variation is unknown. Here we perform a systematic classification of allelic imbalance in mouse hybrids derived from reciprocal crosses of divergent strains. We observe that deviation from balanced biallelic expression is common, occurring in ?20% of the mouse transcriptome in a given tissue. Allelic imbalance attributed to genotypic variation is by far the most prevalent class and typically is tissue-specific. However, some genotype-based imbalance is maintained across tissues and is associated with greater genetic variation, especially in 5' and 3' termini of transcripts. We further identify novel random monoallelic and imprinted genes and find that genotype can modify penetrance of parental origin even in the setting of large imprinted regions. Examination of nascent transcripts in single cells from inbred parental strains reveals that genes showing genotype-based imbalance in hybrids can also exhibit monoallelic expression in isogenic backgrounds. This surprising observation may suggest a competition between alleles and/or reflect the combined impact of cis- and trans-acting variation on expression of a given gene. Our findings provide novel insights into gene regulation and may be relevant to human genetic variation and disease. PMID:25858912

  10. Studies of generalized elemental imbalances in neurological disease patients using INAA (instrumental neutron activation analysis)

    SciTech Connect

    Ehmann, W.D.; Vance, D.E.; Khare, S.S.; Kasarskis, E.J.; Markesbery, W.R.

    1988-01-01

    Evidence has been presented in the literature to implicate trace elements in the etiology of several age-related neurological diseases. Most of these studies are based on brain analyses. Using instrumental neutron activation analysis (INAA), we have observed trace element imbalances in brains of patients with Alzheimer's disease, amyotrophic lateral sclerosis (ALS), and Picks's disease. The most prevalent elemental imbalances found in the brain were for bromine, mercury, and the alkali metals. In this study the authors report INAA studies of trace elements in nonneural tissues from Alzheimer's disease and ALS patients. Samples from household relatives were collected for use as controls wherever possible. Hair samples were washed according to the International Atomic Energy Agency recommended procedure. Fingernail samples were scraped with a quartz knife prior to washing by the same procedure. For ALS patients, blood samples were also collected. These data indicate that elemental imbalances in Alzheimer's disease and ALS are not restricted to the brain. Many elements perturbed in the brain are also altered in the several nonneural tissues examined to date. The imbalances in different tissues, however, are not always in the same direction. The changes observed may represent causes, effects, or simply epiphenomena. Longitudinal studies of nonneural tissues and blood, as well as tissue microprobe analyses at the cellular and subcellular level, will be required in order to better assess the role of trace elements in the etiology of these diseases.

  11. Fatigue-Related Loading Imbalance on the Shank in Running: A Possible Factor in Stress Fractures

    Microsoft Academic Search

    J. Mizrahi; O. Verbitsky; E. Isakov

    2000-01-01

    In previous reports we have shown that in long distance running the impact acceleration on the shank increases with progressing fatigue. The aim of the present study was to test whether, in parallel to this increase, an imbalance in the activities between the ankle plantar and dorsi flexor muscles develops. The tests were made on fourteen subjects during 30 min

  12. Can ankle imbalance be a risk factor for tensor fascia lata muscle weakness?

    Microsoft Academic Search

    Maria L. Zampagni; I. Corazza; A. Paladini Molgora; M. Marcacci

    2009-01-01

    Risk factors that can determine knee and ankle injuries have been investigated and causes are probably multifactorial. A possible explanation could be related by the temporary inhibition of muscular control following an alteration of proprioceptive regulation due to the ankle imbalance pathology. The purpose of our study was to validate a new experimental set up to quantify two kinesiologic procedures

  13. Studies of trace element imbalances in Alzheimer's disease using sequential NAA

    SciTech Connect

    Ehmann, W.D.; Markesbery, W.R.; Thompson, C.M.; Vance, D.E.; Mao, Y.

    1986-01-01

    Evidence has accumulated in the literature that trace elements may be implicated in the etiology of Alzheimer's disease (AD) and other age-related neurological diseases. Even if elemental imbalances do not prove to be causative factors, observed perturbations may be markers that could aid in diagnosis, or help elucidate pathological processes. In this paper the authors present new data for trace element levels in three areas of the human brain most severely affected by AD (hippocampus, amygdala, and nucleus basalis) and in AD hair and nail samples. In some cases the specific imbalances seen previously in the bulk brain analyses are amplified in these regions. Elevated bromine levels seen in AD brain are also observed in AD hair and nail. Significant alkali metal and mercury imbalances with respect to controls occur in AD nail samples. The role of these trace element alterations in the etiology of AD has still not been determined. However, some possible physiological effects include: membrane dysfunction (alkali metals), enzyme inhibition (mercury and bromine), and interference with neurotransmitter functions (mercury, bromine, and alkali metals). The simultaneous multielement capability of this sequential NAA procedure also permits interelement correlation studies. Elemental associations may help identify potential environmental factors that could contribute to the observed trace element imbalances.

  14. On the Imbalance Between the Real Estate Market and the Stock Markets in China

    Microsoft Academic Search

    GAIYAN ZHANG; HUNG-GAY FUNG

    2006-01-01

    This article explores the imbalance between China's real estate market, which is booming, and the stock market, which has plunged over four years. Our empirical analysis shows that the two markets are systematically negatively related due to fund flows. The plummeting stock indexes are partly caused by the surge in the property market. In the meantime, the stock composite index

  15. Comparison of 2 techniques for regional antibiotic delivery to the equine forelimb: intraosseous perfusion vs. intravenous perfusion.

    PubMed Central

    Butt, T D; Bailey, J V; Dowling, P M; Fretz, P B

    2001-01-01

    The purpose of this study was to compare the synovial fluid concentrations and pharmacokinetics of amikacin in the equine limb distal to the carpus following intraosseous and intravenous regional perfusion. The front limbs of 6 horses were randomly assigned to either intraosseous or intravenous perfusion. A tourniquet was placed distal to each carpus and the limb perfused with 500 mg of amikacin. Systemic blood samples and synovial fluid samples were collected over 70 min from the distal interphalangeal (DIP) joint, metacarpophalangeal joint, and digital flexor sheath. The tourniquet was removed following the 30 min sample collection. The mean peak amikacin concentration for the DIP joint was significantly higher with intravenous perfusion. There were no significant differences in time to peak concentration or elimination half-life between methods at each synovial structure. Each technique produced mean peak concentrations ranging from 5 to 50 times that of recommended peak serum concentrations for therapeutic efficacy. PMID:11519271

  16. A pilot prospective study on closed loop controlled ventilation and oxygenation in ventilated children during the weaning phase

    PubMed Central

    2012-01-01

    Introduction The present study is a pilot prospective safety evaluation of a new closed loop computerised protocol on ventilation and oxygenation in stable, spontaneously breathing children weighing more than 7 kg, during the weaning phase of mechanical ventilation. Methods Mechanically ventilated children ready to start the weaning process were ventilated for five periods of 60 minutes in the following order: pressure support ventilation, adaptive support ventilation (ASV), ASV plus a ventilation controller (ASV-CO2), ASV-CO2 plus an oxygenation controller (ASV-CO2-O2) and pressure support ventilation again. Based on breath-by-breath analysis, the percentage of time with normal ventilation as defined by a respiratory rate between 10 and 40 breaths/minute, tidal volume > 5 ml/kg predicted body weight and end-tidal CO2 between 25 and 55 mmHg was determined. The number of manipulations and changes on the ventilator were also recorded. Results Fifteen children, median aged 45 months, were investigated. No adverse event and no premature protocol termination were reported. ASV-CO2 and ASV-CO2-O2 kept the patients within normal ventilation for, respectively, 94% (91 to 96%) and 94% (87 to 96%) of the time. The tidal volume, respiratory rate, peak inspiratory airway pressure and minute ventilation were equivalent for all modalities, although there were more automatic setting changes in ASV-CO2 and ASV-CO2-O2. Positive end-expiratory pressure modifications by ASV-CO2-O2 require further investigation. Conclusion Over the short study period and in this specific population, ASV-CO2 and ASV-CO2-O2 were safe and kept the patient under normal ventilation most of the time. Further research is needed, especially for positive end-expiratory pressure modifications by ASV-CO2-O2. Trial registration ClinicalTrials.gov: NCT01095406 PMID:22591622

  17. Effects of passive limb movement on pulmonary ventilation.

    PubMed Central

    Waisbren, S. J.; Whiting, C. S.; Nadel, E. R.

    1990-01-01

    This study was undertaken to determine if the observed increase in ventilation during passive limb movement was a reflex hyperventilation or a response to an increased metabolic need for oxygen. Experiments on human volunteers were designed to test the hypothesis that the rapid increase of ventilation at the onset of exercise was due to stimulation of the joints. Results of these studies showed significant increases in ventilation, oxygen consumption, carbon dioxide production, ventilation/oxygen consumption ratio, and heart rate compared to rest and recovery values. The data lead to the conclusion that the rapid increase of ventilation at the onset of exercise is a true hyperventilation and that stimulation of the joints can be a significant contributor to increased pulmonary ventilation. PMID:2092413

  18. Ethical challenges in home mechanical ventilation: A secondary analysis

    PubMed Central

    Dybwik, Knut; Nielsen, Erik Waage; Brinchmann, Berit Støre

    2012-01-01

    The aim of this study was to explore the ethical challenges in home mechanical ventilation based on a secondary analysis of qualitative empirical data. The data included perceptions of healthcare professionals in hospitals and community health services and family members of children and adults using home mechanical ventilation. The findings show that a number of ethical challenges, or dilemmas, arise at all levels in the course of treatment: deciding who should be offered home mechanical ventilation, respect for patient and family wishes, quality of life, dignity and equal access to home mechanical ventilation. Other challenges were the impacts home mechanical ventilation had on the patient, the family, the healthcare services and the allocation of resources. A better and broader understanding of these issues is crucial in order to improve the quality of care for both patient and family and assist healthcare professionals involved in home mechanical ventilation to make decisions for the good of the patient and his or her family. PMID:22183963

  19. Changed Skin Blood Perfusion in the Fingertip Following Acupuncture Needle Introduction as Evaluated by Laser Doppler Perfusion Imaging

    Microsoft Academic Search

    G. Litscher; L. Wang; E. Huber; G. Nilsson

    2002-01-01

    .   Rapidly repeated imaging of the left middle fingertip skin blood perfusion was performed in 51 healthy volunteers (mean age±SD:\\u000a 25.3±7.6 years) prior to, immediately after and in the early reperfusion phase following introduction of an acupuncture needle\\u000a at the Neiguan point (Pe. 6) and at a placebo point respectively, using a Laser Doppler Perfusion Imager (LDPI). The average\\u000a skin

  20. Surgical pneumothorax under spontaneous ventilation—effect on oxygenation and ventilation

    PubMed Central

    Pompeo, Eugenio; Fabbi, Eleonora; Dauri, Mario

    2015-01-01

    Surgical pneumothorax allows obtaining comfortable surgical space for minimally invasive thoracic surgery, under spontaneous ventilation and thoracic epidural anesthesia, without need to provide general anesthesia and neuromuscular blockade. One lung ventilation (OLV) by iatrogenic lung collapse, associated with spontaneous breathing and lateral position required for the surgery, involves pathophysiological consequences for the patient, giving rise to hypoxia, hypercapnia, and hypoxic pulmonary vasoconstriction (HPV). Knowledge of these changes is critical to safely conduct this type of surgery. Surgical pneumothorax can be now considered a safe technique that allows the realization of minimally invasive thoracic surgery in awake patients with spontaneous breathing, avoiding the risks of general anesthesia and ensuring a more physiological surgical course.

  1. Chest Compression Synchronized Ventilation versus Intermitted Positive Pressure Ventilation during Cardiopulmonary Resuscitation in a Pig Model

    PubMed Central

    Kill, Clemens; Galbas, Monika; Neuhaus, Christian; Hahn, Oliver; Wallot, Pascal; Kesper, Karl; Wulf, Hinnerk; Dersch, Wolfgang

    2015-01-01

    Background Guidelines recommend mechanical ventilation with Intermitted Positive Pressure Ventilation (IPPV) during resuscitation. The influence of the novel ventilator mode Chest Compression Synchronized Ventilation (CCSV) on gas exchange and arterial blood pressure compared with IPPV was investigated in a pig model. Methods In 12 pigs (general anaesthesia/intubation) ventricular fibrillation was induced and continuous chest compressions were started after 3min. Pigs were mechanically ventilated in a cross-over setting with 5 ventilation periods of 4min each: Ventilation modes were during the first and last period IPPV (100% O2, tidalvolumes = 7ml/kgKG, respiratoryrate = 10/min), during the 2nd, 3rd and 4th period CCSV (100% O2), a pressure-controlled and with each chest compression synchronized breathing pattern with three different presets in randomized order. Presets: CCSVA: Pinsp = 60mbar, inspiratorytime = 205ms; CCSVB: Pinsp = 60mbar, inspiratorytime = 265ms; CCSVC: Pinsp = 45mbar, inspiratorytime = 265ms. Blood gas samples were drawn for each period, mean arterial (MAP) and centralvenous (CVP) blood pressures were continuously recorded. Results as median (25%/75%percentiles). Results Ventilation with each CCSV mode resulted in higher PaO2 than IPPV: PaO2: IPPVfirst: 19.6(13.9/36.2)kPa, IPPVlast: 22.7(5.4/36.9)kPa (p = 0.77 vs IPPVfirst), CCSVA: 48.9(29.0/58.2)kPa (p = 0.028 vs IPPVfirst, p = 0.0001 vs IPPVlast), CCSVB: 54.0 (43.8/64.1) (p = 0.001 vs IPPVfirst, p = 0.0001 vs IPPVlast), CCSVC: 46.0 (20.2/58.4) (p = 0.006 vs IPPVfirst, p = 0.0001 vs IPPVlast). Both the MAP and the difference MAP-CVP did not decrease during twelve minutes CPR with all three presets of CCSV and were higher than the pressures of the last IPPV period. Conclusions All patterns of CCSV lead to a higher PaO2 and avoid an arterial blood pressure drop during resuscitation compared to IPPV in this pig model of cardiac arrest. PMID:26011525

  2. Imbalances of gamma globulin subgroups and gene defects in patients with primary hypogammaglobulinemia

    PubMed Central

    Yount, W. J.; Hong, R.; Seligmann, M.; Good, R.; Kunkel, H. G.

    1970-01-01

    Analysis of immunoglobulin classes, ?G subgroups, and Gm genetic markers from 59 patients with various types of immune deficiencies was undertaken to assess the function of the several cistrons concerned with synthesis of gamma globulins. 13 patients including two sibling pairs were found to have ?G subgroup imbalances. All of these patients had non sex-linked disease. 11 of the 13 had preponderance of the ?G3 subgroup. In most instances of ?G3 preponderance it was the Gm(b) type of ?G3 that was selectively retained; the Gm(g) type, controlled by the allelic gene was markedly depressed but not absent in the cases where it could be studied. Other imbalances, either seen concomitantly with ?G3 preponderance or independently, included predominance of the ?G2 subgroup and selective absence of single ?G subgroups. One family was encountered with probable structural gene abnormalities in the autosomal Gm loci. Both parents had different abnormal gene complexes detectable by absence of specific Gm markers and the propositus received both types from the parents. Similar gene complexes have been seen previously in rare instances through population screening but only in the heterozygous state and were not associated with clinically evident hypogammaglobulinemia. Of several other families of patients with subgroup imbalance, two were informative in that structural gene defects could be excluded. Studies on 22 first degree relatives of patients with subgroup imbalances indicated that the most common abnormality detected was in ?A which was absent in 3 and markedly decreased in 2 others; other abnormalities included decreased levels of specific genetic types of ?G globulin. It is concluded that ?G subgroup imbalances are frequently found in non sex-linked immunoglobulin deficiency disorders and in some instances may be associated with family abnormalities suggesting either regulator or structural gene defects. PMID:4097659

  3. Photospheric Magnetic Field: Relationship Between North-South Asymmetry and Flux Imbalance

    NASA Astrophysics Data System (ADS)

    Vernova, E. S.; Tyasto, M. I.; Baranov, D. G.

    2014-08-01

    Photospheric magnetic fields were studied using the Kitt Peak synoptic maps for 1976 - 2003. Only strong magnetic fields ( B>100 G) of the equatorial region were taken into account. The north-south asymmetry of the magnetic fluxes was considered as well as the imbalance between positive and negative fluxes. The north-south asymmetry displays a regular alternation of the dominant hemisphere during the solar cycle: the northern hemisphere dominated in the ascending phase, the southern one in the descending phase during Solar Cycles 21 - 23. The sign of the imbalance did not change during the 11 years from one polar-field reversal to the next and always coincided with the sign of the Sun's polar magnetic field in the northern hemisphere. The dominant sign of leading sunspots in one of the hemispheres determines the sign of the magnetic-flux imbalance. The sign of the north-south asymmetry of the magnetic fluxes and the sign of the imbalance of the positive and the negative fluxes are related to the quarter of the 22-year magnetic cycle where the magnetic configuration of the Sun remains constant (from the minimum where the sunspot sign changes according to Hale's law to the magnetic-field reversal and from the reversal to the minimum). The sign of the north-south asymmetry for the time interval considered was determined by the phase of the 11-year cycle (before or after the reversal); the sign of the imbalance of the positive and the negative fluxes depends on both the phase of the 11-year cycle and on the parity of the solar cycle. The results obtained demonstrate the connection of the magnetic fields in active regions with the Sun's polar magnetic field in the northern hemisphere.

  4. Suppression of spontaneous breathing during high-frequency jet ventilation

    Microsoft Academic Search

    A. J. van Vught; A. Versprille; J. R. C. Jansen

    1986-01-01

    Conditions which suppress spontaneous breathing activity during high-frequency jet ventilation (HFJV) were analysed in Yorkshire piglets under pentobarbital anesthesia. The highest PaCO2 at which the animals did not breathe against the ventilator (apnea point) was established during different patterns of ventilation, either by changing the minute volume or by adding CO2 to the inspiratory gas. Arterial oxygen tension was maintained

  5. Ammonia emissions from two mechanically ventilated UK livestock buildings

    NASA Astrophysics Data System (ADS)

    Demmers, T. G. M.; Burgess, L. R.; Short, J. L.; Phillips, V. R.; Clark, J. A.; Wathes, C. M.

    Ammonia emission rates from livestock buildings are required to construct an accurate emission inventory for the UK. Ventilation and ammonia emission rates from a fattening pig unit and a broiler house, both mechanically ventilated, were estimated using fan wheel anemometers and thermal converters with a chemiluminescence NO x-analyser to measure the ventilation rate and the ammonia concentration, respectively. The estimated ammonia emission factors were 46.9 and 16.6 kg lu -1 a -1 for the fattening pig unit and the broiler house, respectively. Both emission factors were within the range reported in the literature. A tracer gas (CO) method, based on a constant tracer release rate, was validated for measuring ventilation rates from naturally ventilated livestock buildings. Air inlets and outlets were identified using the air temperature or tracer concentration in the opening. Tracer concentration was found to be a more suitable criterion than temperature. In both houses, a significant correlation between the estimated ventilation rate using the tracer method and the measured ventilation rate using fan wheel anemometers was found. The ventilation rate was underestimated by 12 and 6% for the piggery and broiler house, respectively. The instantaneous ammonia emission derived from the tracer gas method was lower than the ammonia emission derived from the fan wheel anemometer method by 14 and 16% for the piggery and broiler house, respectively. The ventilation and ammonia emission estimates using the tracer method were within acceptable range from the ventilation and emission rates measured using measuring fans, but because of its accuracy and simplicity the fan wheel anemometer method is preferred for long-term measurements of ventilation rate in mechanically ventilated buildings.

  6. Humidification method that decreases condensate contamination in ventilator tubing

    Microsoft Academic Search

    Frank Austan; Masayuki Suzukawa

    2000-01-01

    OBJECTIVE: To demonstrate combining unheated bubble-through humidifier with a heart-moisture exchanger filter for the purpose of decreasing condensate contamination in mechanical ventilator tubing.DESIGN: Single-case, pretest and posttest.SETTING: University-affiliated and nonprofit hospital.PATIENT: A 32-year-old man with Pickwickian syndrome and pneumonia caused by Pseudomonas aeruginosa received mechanical ventilation for 14 days.METHODS: Ventilator tubing was cultured in two 24-hour trials, using a pretest

  7. Recommended Ventilation Strategies for Energy-Efficient Production Homes

    SciTech Connect

    Roberson, J.; Brown, R.; Koomey, J.; Warner, J.; Greenberg, S.

    1998-12-01

    This report evaluates residential ventilation systems for the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR{reg_sign} Homes program and recommends mechanical ventilation strategies for new, low-infiltration, energy-efficient, single-family, ENERGY STAR production (site-built tract) homes in four climates: cold, mixed (cold and hot), hot humid, and hot arid. Our group in the Energy Analysis Department at Lawrence Berkeley National Lab compared residential ventilation strategies in four climates according to three criteria: total annualized costs (the sum of annualized capital cost and annual operating cost), predominant indoor pressure induced by the ventilation system, and distribution of ventilation air within the home. The mechanical ventilation systems modeled deliver 0.35 air changes per hour continuously, regardless of actual infiltration or occupant window-opening behavior. Based on the assumptions and analysis described in this report, we recommend independently ducted multi-port supply ventilation in all climates except cold because this strategy provides the safety and health benefits of positive indoor pressure as well as the ability to dehumidify and filter ventilation air. In cold climates, we recommend that multi-port supply ventilation be balanced by a single-port exhaust ventilation fan, and that builders offer balanced heat-recovery ventilation to buyers as an optional upgrade. For builders who continue to install forced-air integrated supply ventilation, we recommend ensuring ducts are airtight or in conditioned space, installing a control that automatically operates the forced-air fan 15-20 minutes during each hour that the fan does not operate for heating or cooling, and offering ICM forced-air fans to home buyers as an upgrade.

  8. Myocardial perfusion scintigraphy: past, present and future

    PubMed Central

    Notghi, A; Low, C S

    2011-01-01

    During the last two decades, radionuclide myocardial perfusion scintigraphy (MPS) has become established as the main functional cardiac imaging technique for the assessment of ischaemic heart disease (IHD). Despite a growing number of alternative functional imaging techniques, MPS still remains the most widely used technique, with a wealth of literature supporting its usefulness in assessing IHD and predicting prognosis. The technique itself has evolved, making it more reliable and robust, with additional ventricular functional information that further defines the prognosis in these patients. With the advent of hybrid single photon emission with CT and positron emission tomography with CT cameras together with the development of new camera technology that enables faster images with less radiation and better resolution, MPS will remain an essential part of IHD investigation. There are new promising radiopharmacological developments and applications such as radiolabelled fatty acids and meta-iodobenzylguanidine. These will widen the scope of nuclear medicine imaging to include patients with cardiac failure and acute chest pain presenting to accident and emergency departments. Nuclear medicine cardiac investigations will continue to have an essential role in the diagnosis, stratification and prognosis of patients with cardiac disease, complementing the new developing cardiac modalities such as CT coronary angiography and MRI. PMID:22723530

  9. In Vitro Perfused Human Capillary Networks

    PubMed Central

    Moya, Monica L.; Hsu, Yu-Hsiang; Lee, Abraham P.; Hughes, Christopher C.W.

    2013-01-01

    Replicating in vitro the complex in vivo tissue microenvironment has the potential to transform our approach to medicine and also our understanding of biology. In order to accurately model the 3D arrangement and interaction of cells and extracellular matrix, new microphysiological systems must include a vascular supply. The vasculature not only provides the necessary convective transport of oxygen, nutrients, and waste in 3D culture, but also couples and integrates the responses of organ systems. Here we combine tissue engineering and microfluidic technology to create an in vitro 3D metabolically active stroma (?1?mm3) that, for the first time, contains a perfused, living, dynamic, interconnected human capillary network. The range of flow rate (?m/s) and shear rate (s?1) within the network was 0–4000 and 0–1000, respectively, and thus included the normal physiological range. Infusion of FITC dextran demonstrated microvessels (15–50??m) to be largely impermeable to 70?kDa. Our high-throughput biology-directed platform has the potential to impact a broad range of fields that intersect with the microcirculation, including tumor metastasis, drug discovery, vascular disease, and environmental chemical toxicity. PMID:23320912

  10. ENERGY IMPACTS OF VARIOUS RESIDENTIAL MECHANICAL VENTILATION STRATEGIES 

    E-print Network

    Vieira, R.; Parker, D.; Lixing, G.; Wichers, M.

    2008-01-01

    ENERGY IMPACTS OF VARIOUS RESIDENTIAL MECHANICAL VENTILATION STRATEGIES Robin K. Vieira, Buildings. Research Division Director Danny S. Parker Principal Research Scientist Lixing Gu Principal Research Engineer Michael Wichers...

  11. Temperature profiles in forced-ventilation enclosure fires

    SciTech Connect

    Backovsky, J.; Foote, K.L.; Alvares, N.J.

    1988-02-01

    We investigated the effect of ventilation rate, ventilation configuration, fire elevation, and the presence of a plenum (suspended ceiling) on the fire compartment temperatures during forced ventilated methane gas fires (100-400 kW). We found that with low air-inlet positions, fires with ventilation rates greater than 2 to 3 times the stoichiometrically required air (referred to here as well-ventilated fires) produce two-layer temperature profiles; fires with a lower ventilation rate (under-ventilated fires) produce single-layer profiles with a temperature gradient. Higher temperatures throughout the enclosure are seen in underventilated fires as compared to well-ventilated fires. We observed that high air-inlet locations perturb the two-layer temperature profile of the well-ventilated fire, cooling the upper layer and heating the lower layer. For underventilated fires, high air-inlet locations lower temperatures in the enclosure but do not perturb the profile shape. Elevated fires and fires in a compartment with a plenum were seen to behave similarly for the same distance from fire base to ceiling, producing hotter layers the shorter the distance. 9 refs., 13 figs.

  12. Effects of infant ventilator design on spontaneous breathing.

    PubMed

    Kopotic, R J; Mannino, F L

    1987-01-01

    Study of the mechanical work of spontaneous breaths taken by eight infants attached to infant ventilators. Work was estimated from the volume displacement and pressure fluctuations of breathing during steady state mechanical ventilator conditions (i.e., stable peak or PEEP pressures). A broad difference existed between manufacturers of infant ventilators; a dramatic reduction was seen in work when attached to a demand as compared to a continuous flow device. Additionally, some change in work occurred, depending on the phase of the IMV cycle in which spontaneous breath was taken. Dynamic testing of ventilators can reveal differences in function. PMID:3505266

  13. Field evaluation of ventilation system performance in enclosed parking garages

    SciTech Connect

    Ayari, A.M.; Grot, D.A.; Krarti, M.

    2000-07-01

    This paper summarizes the results of a field study to determine the ventilation requirements and the contaminant levels in existing enclosed parking garages. The testing was conducted in seven parking garages with different sizes, traffic flow patterns, vehicle types, and locations. In particular, the study compares the actual ventilation rates measured using the tracer gas technique with the ventilation requirements of ANSI/ASHRAE Standard 62-1989. In addition, the field test evaluated the effectiveness of the existing ventilation systems in maintaining acceptable contaminant levels within enclosed parking garages.

  14. Evaluation of design ventilation requirements for enclosed parking facilities

    SciTech Connect

    Ayari, A.; Krarti, M.

    2000-07-01

    This paper proposes a new design approach to determine the ventilation requirements for enclosed parking garages. The design approach accounts for various factors that affect the indoor air quality within a parking facility, including the average CO emission rate, the average travel time, the number of cars, and the acceptable CO level within the parking garage. This paper first describes the results of a parametric analysis based on the design method that was developed. Then the design method is presented to explain how the ventilation flow rate can be determined for any enclosed parking facility. Finally, some suggestions are proposed to save fan energy for ventilating parking garages using demand ventilation control strategies.

  15. Intermittent daytime mouthpiece ventilation successfully augments nocturnal non-invasive ventilation, controlling ventilatory failure and maintaining patient independence.

    PubMed

    Ward, Karen; Ford, Verity; Ashcroft, Helen; Parker, Robert

    2015-01-01

    A 53-year-old woman with spinal muscular atrophy and a 7-year history of nocturnal non-invasive ventilation (NIV) use via nasal mask and chinstrap was admitted electively. Outpatient review suggested symptomatic hypercapnia and hypoxaemia. Use of her usual NIV resulted in early morning respiratory acidosis due to excess mouth leak, and continuous face mask NIV was instigated while in hospital. Once stabilised, she elected to return to nasal ventilation. At outpatient review, respiratory acidosis reoccurred despite diurnal use of NIV. Using the patient's routine ventilator and a novel mouthpiece and trigger algorithm, intermittent daytime mouthpiece ventilation (MPV) was introduced alongside overnight NIV. Control of respiratory failure was achieved and, vitally, independent living maintained. Intermittent MPV was practicable and effective where the limits of ventilator tolerance had otherwise been reached. MPV may reduce the need for tracheostomy ventilation and this case serves as a reminder of the increasing options routinely available to NIV clinicians. PMID:26160549

  16. Noninvasive ventilation in acute hypercapnic respiratory failure.

    PubMed

    Pisani, Lara; Nava, Stefano

    2014-08-01

    Noninvasive mechanical ventilation (NIV) improves gas exchange and clinical outcome in various types of acute respiratory failure. Acute exacerbation of chronic obstructive pulmonary disease is a frequent cause of acute hypercapnic respiratory failure (AHRF). According to several randomized controlled trials, the addition of NIV to standard medical therapy reduces mortality, intubation rate, and hospital length of stay in these patients. Indications for the use of NIV have expanded over the past decade. In this article, we discuss the clinical indications and goals of NIV in the management of AHRF. PMID:25111646

  17. Noninvasive ventilation in acute respiratory failure.

    PubMed

    Mehta, S; Hill, N S

    1996-06-01

    Noninvasive PPV has been employed for decades in patients with chronic respiratory failure. Increasing use in patients with acute respiratory failure is a more recent phenomenon, mainly because of advances in noninvasive interfaces and ventilator modes. Noninvasive PPV delivered by nasal or oronasal mask has been demonstrated to reduce the need for endotracheal intubation, decrease lengths of stay in the ICU and hospital, and possibly reduce mortality. In the acute care setting, evidence now demonstrates the efficacy of noninvasive PPV for acute exacerbations of COPD, pulmonary edema, pulmonary contusions, and acute respiratory failure in patients who decline or who are not believed to be candidates for intubation. No firm conclusions can yet be made regarding patients with respiratory failure due to other causes, but studies suggest that noninvasive PPV may also be of benefit in patients with postoperative respiratory insufficiency, chest wall disease, and cystic fibrosis. Several factors are vital to the success of this therapy, including careful patient selection, properly timed intervention, a comfortable, well-fitting interface, patient coaching and encouragement, and careful monitoring. Noninvasive ventilation should be used as a way to avoid endotracheal intubation rather than as an alternative. Accordingly, a trial of noninvasive ventilation should be instituted in the course of acute respiratory failure before respiratory arrest is imminent, to provide ventilatory assistance while the factors responsible for the respiratory failure are aggressively treated. Moreover, the authors favor conservative management with expeditious intubation in patients who have other conditions that place them at risk during use of noninvasive ventilation or in patients failing to respond to noninvasive PPV. Noninvasive PPV clearly represents an important addition to the techniques available to manage patients with acute respiratory failure; however, because most studies have been retrospective and uncontrolled, many issues remain unresolved. Further controlled studies are needed to confirm the safety and efficacy of noninvasive PPV, evaluate the most appropriate selection of patients and timing of intervention, define the best type of interface, and assess the costs of noninvasive PPV in comparison with conventional therapy. PMID:9390883

  18. C-106 tank process ventilation test

    SciTech Connect

    Bailey, J.W.

    1998-07-20

    Project W-320 Acceptance Test Report for tank 241-C-106, 296-C-006 Ventilation System Acceptance Test Procedure (ATP) HNF-SD-W320-012, C-106 Tank Process Ventilation Test, was an in depth test of the 296-C-006 ventilation system and ventilation support systems required to perform the sluicing of tank C-106. Systems involved included electrical, instrumentation, chiller and HVAC. Tests began at component level, moved to loop level, up to system level and finally to an integrated systems level test. One criteria was to perform the test with the least amount of risk from a radioactive contamination potential stand point. To accomplish this a temporary configuration was designed that would simulate operation of the systems, without being connected directly to the waste tank air space. This was done by blanking off ducting to the tank and connecting temporary ducting and an inlet air filter and housing to the recirculation system. This configuration would eventually become the possible cause of exceptions. During the performance of the test, there were points where the equipment did not function per the directions listed in the ATP. These events fell into several different categories. The first and easiest problems were field configurations that did not match the design documentation. This was corrected by modifying the field configuration to meet design documentation and reperforming the applicable sections of the ATP. A second type of problem encountered was associated with equipment which did not operate correctly, at which point an exception was written against the ATP, to be resolved later. A third type of problem was with equipment that actually operated correctly but the directions in the ATP were in error. These were corrected by generating an Engineering Change Notice (ECN) against the ATP. The ATP with corrected directions was then re-performed. A fourth type of problem was where the directions in the ATP were as the equipment should operate, but the design of the equipment was not correct for that type of operation. To correct this problem an ECN was generated against the design documents, the equipment modified accordingly, and the ATP re-performed. The last type of problem was where the equipment operated per the direct ions in the ATP, agreed with the design documents, yet violated requirements of the Basis of Interim Operation (BIO). In this instance a Non Conformance Report (NCR) was generated. To correct problems documented on an NCR, an ECN was generated to modify the design and field work performed, followed by retesting to verify modifications corrected noted deficiencies. To expedite the completion of testing and maintain project schedules, testing was performed concurrent with construct on, calibrations and the performance of other ATP`s.

  19. Guide to Closing and Conditioning Ventilated Crawlspaces

    SciTech Connect

    Dickson, B.

    2013-01-01

    This how-to guide explains the issues and concerns with conventional ventilated crawlspaces and provides prescriptive measures for improvements that will create healthier and more durable spaces. The methods described in this guide are not the only acceptable ways to treat a crawlspace but represent a proven strategy that works in many areas of the United States. The designs discussed in this guide may or may not meet the local building codes and as such will need to be researched before beginning the project.

  20. 30 CFR 77.212 - Draw-off tunnel ventilation fans; installation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false Draw-off tunnel ventilation fans; installation. 77...Installations § 77.212 Draw-off tunnel ventilation fans; installation. When fans are used to ventilate draw-off tunnels the fans shall be: (a)...

  1. 30 CFR 77.212 - Draw-off tunnel ventilation fans; installation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Draw-off tunnel ventilation fans; installation. 77...Installations § 77.212 Draw-off tunnel ventilation fans; installation. When fans are used to ventilate draw-off tunnels the fans shall be: (a)...

  2. 30 CFR 77.212 - Draw-off tunnel ventilation fans; installation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Draw-off tunnel ventilation fans; installation. 77...Installations § 77.212 Draw-off tunnel ventilation fans; installation. When fans are used to ventilate draw-off tunnels the fans shall be: (a)...

  3. 30 CFR 77.212 - Draw-off tunnel ventilation fans; installation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Draw-off tunnel ventilation fans; installation. 77...Installations § 77.212 Draw-off tunnel ventilation fans; installation. When fans are used to ventilate draw-off tunnels the fans shall be: (a)...

  4. 30 CFR 77.212 - Draw-off tunnel ventilation fans; installation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Draw-off tunnel ventilation fans; installation. 77...Installations § 77.212 Draw-off tunnel ventilation fans; installation. When fans are used to ventilate draw-off tunnels the fans shall be: (a)...

  5. Waste tank ventilation rates measured with a tracer gas method

    SciTech Connect

    Huckaby, J.L.; Evans, J.C.; Sklarew, D.S.; Mitroshkov, A.V.

    1998-08-01

    Passive ventilation with the atmosphere is used to prevent accumulation of waste gases and vapors in the headspaces of 132 of the 177 high-level radioactive waste Tanks at the Hanford Site in Southeastern Washington State. Measurements of the passive ventilation rates are needed for the resolution of two key safety issues associated with the rates of flammable gas production and accumulation and the rates at which organic salt-nitrate salt mixtures dry out. Direct measurement of passive ventilation rates using mass flow meters is not feasible because ventilation occurs va multiple pathways to the atmosphere (i.e., via the filtered breather riser and unsealed tank risers and pits), as well as via underground connections to other tanks, junction boxes, and inactive ventilation systems. The tracer gas method discussed in this report provides a direct measurement of the rate at which gases are removed by ventilation and an indirect measurement of the ventilation rate. The tracer gas behaves as a surrogate of the waste-generated gases, but it is only diminished via ventilation, whereas the waste gases are continuously released by the waste and may be subject to depletion mechanisms other than ventilation. The fiscal year 1998 tracer studies provide new evidence that significant exchange of air occurs between tanks via the underground cascade pipes. Most of the single-shell waste tanks are connected via 7.6-cm diameter cascade pipes to one or two adjacent tanks. Tracer gas studies of the Tank U-102/U-103 system indicated that the ventilation occurring via the cascade line could be a significant fraction of the total ventilation. In this two-tank cascade, air evidently flowed from Tank U-103 to Tank U-102 for a time and then was observed to flow from Tank U-102 to Tank U-103.

  6. Fluid absorption in isolated perfused colonic crypts.

    PubMed Central

    Singh, S K; Binder, H J; Boron, W F; Geibel, J P

    1995-01-01

    A spatial segregation of ion transport processes between crypt and surface epithelial cells is well-accepted and integrated into physiological and pathophysiological paradigms of small and large intestinal function: Absorptive processes are believed to be located in surface (and villous) cells, whereas secretory processes are believed to be present in crypt cells. Validation of this model requires direct determination of fluid movement in intestinal crypts. This study describes the adaptation of techniques from renal tubule microperfusion to hand-dissect and perfuse single, isolated crypts from rat distal colon to measure directly fluid movement. Morphologic analyses of the isolated crypt preparation revealed no extraepithelial cellular elements derived from the lamina propria, including myofibroblasts. In the basal state, crypts exhibited net fluid absorption (mean net fluid movement = 0.34 +/- 0.01 nl.mm-1.min-1), which was Na+ and partially HCO3- dependent. Addition of 1 mM dibutyryl-cyclic AMP, 60 nM vasoactive intestinal peptide, or 0.1 mM acetylcholine to the bath (serosal) solution reversibly induced net fluid secretion (net fluid movement approximately -0.35 +/- 0.01 nl.mm-1.min-1). These observations permit speculation that absorption is a constitutive transport function in crypt cells and that secretion by crypt cells is regulated by one or more neurohumoral agonists that are released in situ from lamina propria cells. The functional, intact polarized crypt described here that both absorbs and secretes will permit future studies that dissect the mechanisms that govern fluid and electrolyte movement in the colonic crypt. Images PMID:7593625

  7. Tomographic Digital Subtraction Angiography for Lung Perfusion Estimation in Rodents

    PubMed Central

    Badea, Cristian T.; Hedlund, Laurence W.; De Lin, Ming; Boslego Mackel, Julie S.; Samei, Ehsan; Johnson, G. Allan

    2009-01-01

    In vivo measurements of perfusion present a challenge to existing small animal imaging techniques such as magnetic resonance microscopy (MRM), microCT, microPET, and microSPECT, due to combined requirements for high spatial and temporal resolution. We demonstrate the use of Tomographic Digital Subtraction Angiography (TDSA) for estimation of perfusion in small animals. TDSA augments conventional digital subtraction angiography (DSA) by providing three-dimensional spatial information using tomosynthesis algorithms. TDSA is based on the novel paradigm that the same time density curves can be reproduced in a number of consecutive injections of ?L volumes of contrast at a series of different angles of rotation. The capabilities of TDSA are established in studies on lung perfusion in rats. Using an imaging system developed in-house, we acquired data for 4D imaging with temporal resolution of 140 ms, in-plane spatial resolution of 100 microns, and slice thickness on the order of millimeters. Based on a structured experimental approach, we optimized TDSA imaging providing a good tradeoff between slice thickness, the number of injections, contrast-to-noise, and immunity to artifacts. Both DSA and TDSA images were used to create parametric maps of perfusion. TDSA imaging has potential application in a number of areas where functional perfusion measurements in 4D can provide valuable insight into animal models of disease and response to therapeutics. PMID:17555236

  8. Perfused Multiwell Plate for 3D Liver Tissue Engineering

    PubMed Central

    Domansky, Karel; Inman, Walker; Serdy, James; Dash, Ajit; Lim, Matthew H. M.

    2014-01-01

    In vitro models that capture the complexity of in vivo tissue and organ behaviors in a scalable and easy-to-use format are desirable for drug discovery. To address this, we have developed a bioreactor that fosters maintenance of 3D tissue cultures under constant perfusion and we have integrated multiple bioreactors into an array in a multiwell plate format. All bioreactors are fluidically isolated from each other. Each bioreactor in the array contains a scaffold that supports formation of hundreds of 3D microscale tissue units. The tissue units are perfused with cell culture medium circulated within the bioreactor by integrated pneumatic diaphragm micropumps. Electronic controls for the pumps are kept outside the incubator and connected to the perfused multiwell by pneumatic lines. The docking design and open-well bioreactor layout make handling perfused multiwell plates similar to using standard multiwell tissue culture plates. A model of oxygen consumption and transport in the circulating culture medium was used to predict appropriate operating parameters for primary liver cultures. Oxygen concentrations at key locations in the system were then measured as a function of flow rate and time after initiation of culture to determine oxygen consumption rates. After seven days in culture, tissue formed from cells seeded in the perfused multiwell reactor remained functionally viable as assessed by immunostaining for hepatocyte and liver sinusoidal endothelial cell (LSEC) phenotypic markers. PMID:20024050

  9. Axisymmetric, Ventilated Supercavitation in Unsteady, Horizontal Flow

    NASA Astrophysics Data System (ADS)

    Kawakami, Ellison; Lee, Seung-Jae; Arndt, Roger

    2012-11-01

    Drag reduction and/or speed augmentation of marine vehicles by means of supercavitation is a topic of great interest. During the initial launch of a supercavitating vehicle, an artificial supercavity is required until the vehicle can reach conditions at which a natural supercavity can be sustained. Previous studies at Saint Anthony Falls Laboratory (SAFL) focused on the behavior of ventilated supercavities in steady horizontal flows. In open waters, vehicles can encounter unsteady flows, especially when traveling under waves. A study has been carried out at SAFL to investigate the effects of unsteady flow on axisymmetric supercavities. An attempt is made to duplicate sea states seen in open waters. In an effort to track cavity dimensions throughout a wave cycle, an automated cavity tracking script has been developed. Using a high speed camera and the proper software, it is possible to synchronize cavity dimensions with pressure measurements taken inside the cavity. Results regarding supercavity shape, ventilation demand, cavitation parameters and closure methods are presented. It was found that flow unsteadiness caused a decrease in the overall length of the supercavity while having only a minimal effect on the maximum diameter. The supercavity volume varied with cavitation number and a possible relationship between the two is being explored. (Supported by ONR)

  10. Biomass solid fuel and acute respiratory infections: The ventilation factor

    Microsoft Academic Search

    Anayo Fidelis Akunne; Valérie R. Louis; Mamadou Sanon; Rainer Sauerborn

    2006-01-01

    Biomass solid fuel smoke is linked to acute respiratory infections (ARI). In future, its use will likely increase among poor households, and better ventilation is one important measure that can reduce this health impact. The authors aimed to study the extent to which improvement in ventilation-related factors reduces the fraction of ARI attributable to exposure to biomass smoke in children

  11. Hydrogen inhalation ameliorates ventilator-induced lung injury

    Microsoft Academic Search

    Chien-Sheng Huang; Tomohiro Kawamura; Sungsoo Lee; Naobumi Tochigi; Norihisa Shigemura; Bettina M Buchholz; John D Kloke; Timothy R Billiar; Yoshiya Toyoda; Atsunori Nakao

    2010-01-01

    INTRODUCTION: Mechanical ventilation (MV) can provoke oxidative stress and an inflammatory response, and subsequently cause ventilator-induced lung injury (VILI), a major cause of mortality and morbidity of patients in the intensive care unit. Inhaled hydrogen can act as an antioxidant and may be useful as a novel therapeutic gas. We hypothesized that, owing to its antioxidant and anti-inflammatory properties, inhaled

  12. Ventilation and circulation during exercise in Octopus vulgaris

    Microsoft Academic Search

    D. F. Houlihan; G. Duthie; P. J. Smith; M. J. Wells; J. Wells

    1986-01-01

    Ventilation frequency, volume, oxygen uptake, and oxygen transport by the blood have been studied in unrestrained octopus,Octopus vulgaris before, during and after recovery from 20 min of enforced activity. Exercise increased oxygen consumption 2.8 fold. The percentage utilisation of oxygen from the branchial water is maintained or increased at around 35% during activity and the calculated ventilation volume increases by

  13. A COMPARATIVE STUDY ON EVALUATION METHODS OF EMERGENCY VENTILATION STRATEGIES

    Microsoft Academic Search

    Lina Zhao; Xianting Li

    With the occurrence of indoor terrorism attacks and the accidental release of toxic chemicals, people have paid more attentions on such emergency events in recent years. The effective evaluation method of emergency ventilation strategies could help people find out the accurate way to control the ventilation system, and reduce the total loss during the event. In this article, two methods

  14. A simple alarm device for the Bennet PR2 ventilator

    Microsoft Academic Search

    Stephan Stoyanov; Søren Jørgensen

    1978-01-01

    A simple alarm device for use with the Bennet PR-2 ventilator is described. It is based on the operation of a photo-electric cell, is simple in construction, and can be used on other types of ventilators if the pressure gauge is compatible.

  15. The Ventilator-Assisted Child: A Practical Resource Guide.

    ERIC Educational Resources Information Center

    Driver, Lynn E.; Nelson, Virginia Simson; Warschausky, Seth A.

    The 16 chapters comprising this manual are intended to provide a practical guide for meeting the needs of ventilator-assisted children. Chapters have the following titles and authors: (1)"Spectrum of Care" (Virginia Simson Nelson and Lynn E. Driver); (2) "Long-Term Airway Management for the Ventilator-Assisted Child" (Ann Marie Ramsey and…

  16. Thermal comfort evaluation of naturally ventilated public housing in Singapore

    Microsoft Academic Search

    N. H Wong; H Feriadi; P. Y Lim; K. W Tham; C Sekhar; K. W Cheong

    2002-01-01

    Field survey was conducted to evaluate thermal comfort perception of the occupants in naturally ventilated public housing in Singapore. Thermal acceptability assessment was performed to find out whether the naturally ventilated indoor environment meets the ASHRAE Standard-55's 80% acceptability criteria. The study investigated whether thermal perception was influenced by different sessions of the day, building height, and flat types. Comparative

  17. Model Predictive Control of the Hybrid Ventilation for Livestock

    Microsoft Academic Search

    Zhuang Wu; Jakob Stoustrup; Klaus Trangbaek; Per Heiselberg; Martin Riisgaard Jensen

    2006-01-01

    In this paper, design and simulation results of model predictive control (MPC) strategy for livestock hybrid ventilation systems and associated indoor climate through variable valve openings and exhaust fans, are presented. The design is based on thermal comfort parameters for poultry in barns and a dynamic model describing the nonlinear behavior of ventilation and associated climate, by applying a so-called

  18. Ventilated Wall Claddings: Review, Field Performance, and Hygrothermal Modeling

    Microsoft Academic Search

    John Straube; Graham Finch

    The use of ventilated air spaces behind claddings has been shown to influence the performance of some wall assemblies. Recently completed field and laboratory research has shown that cladding ventilation has the potential to increase drying and reduce wetting from absorptive claddings and sun-driven moisture. The use of one-dimensional hygrothermal simulation software has been well established for a wide range

  19. Mechatronics in medical engineering: advanced control of a ventilation device

    Microsoft Academic Search

    F. Simon; I. Jenayeh; H. Rake

    2000-01-01

    A typical mechatronics system consists of a mechanical process, electromechanical actuators, electronic sensors and a controller unit with the corresponding software. In this paper a microcontroller-based digital feedback control of a positioning device for a ventilation machine is presented. This kind of machine should allow either a volume- or a pressure-based controlled ventilation. The interdependence between the two important physiological

  20. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    (b)(1) Ventilation control devices shall be used to provide ventilation to dilute, render harmless, and to carry away flammable, explosive, noxious, and harmful gases, dusts, smoke, and fumes— (i) To each working face from which coal is being cut, mined, drilled for blasting, or loaded;...

  1. A Dynamic Bayesian Network for Diagnosing Ventilator-Associated

    E-print Network

    Utrecht, Universiteit

    A Dynamic Bayesian Network for Diagnosing Ventilator-Associated Pneumonia in ICU Patients Theodore-3275 #12;A Dynamic Bayesian Network for Diagnosing Ventilator-Associated Pneumonia in ICU Patients Theodore Bayesian network that explicitly captures the development of the disease over time. We discuss how

  2. [The establishment and research of ventilator quality control information system].

    PubMed

    Li, Tao; Zhang, Nan; Pu, Wei

    2013-05-01

    Ventilator quality control is an important task for the management of hospital medical equipment. Analysis the problems of hospital medical device quality control and introducing ventilator quality control information system design and technical characteristics. The application of the system can improve the efficiency of quality control, and enhance hospital medical equipment management level. PMID:24015622

  3. Nicotine withdrawal and agitation in ventilated critically ill patients

    Microsoft Academic Search

    Olivier Lucidarme; Amélie Seguin; Cédric Daubin; Michel Ramakers; Nicolas Terzi; Patrice Beck; Pierre Charbonneau; Damien du Cheyron

    2010-01-01

    ABSTRACT: INTRODUCTION: Smoking is highly addictive, and nicotine abstinence is associated with withdrawal syndrome in hospitalized patients. In this study, we aimed to evaluate the impact of sudden nicotine abstinence on the development of agitation and delirium, and on morbidities and outcomes in critically ill patients who required respiratory support, either noninvasive ventilation or intubation, and mechanical ventilation. METHODS: We

  4. Face ventilation for oil-shale mining. Information Circular\\/1986

    Microsoft Academic Search

    E. D. Thimons; C. E. Brechtel; M. E. Adam; J. F. T. Agapito

    1986-01-01

    The Bureau of Mines report presents expected levels of air pollutants in the face areas of oil shale mines, based upon data collected by the authors and previous investigators. Ventilation requirements to maintain these pollutant levels below their threshold limit values and Federal and local mine air quality standards are discussed. Two practical face-ventilation systems are discussed in terms of

  5. Ventilation of patients with asthma and chronic obstructive pulmonary disease

    Microsoft Academic Search

    Yin Peigang; John J. Marini

    2002-01-01

    Ventilatory intervention is often life-saving when patients with asthma or chronic obstructive pulmonary disease (COPD) experience acute respiratory compromise. Although both noninvasive and invasive ventilation methods may be viable initial choices, which is better depends upon the severity of illness, the rapidity of response, coexisting disease, and capacity of the medical environment. In addition, noninvasive ventilation often relieves dyspnea and

  6. Protective ventilation of patients with acute respiratory distress syndrome

    Microsoft Academic Search

    E. D. Moloney; M. J. D. Griffiths

    2004-01-01

    The majority of patients with acute respiratory distress syndrome (ARDS) require mechanical ventilation. This support provides time for the lungs to heal, but the adverse effects of mechanical ventilation significantly influence patient outcome. Traditionally, these were ascribed to mechanical effects, such as haemodynamic compromise from decreased venous return or gross air leaks induced by large transpulmonary pressures. More recently, however,

  7. Large eddy simulations for studying tunnel smoke ventilation

    Microsoft Academic Search

    P. Z. Gao; S. L. Liu; W. K. Chow; N. K. Fong

    2004-01-01

    Computational fluid dynamics are applied to simulate the smoke movement in a ventilated tunnel fire through large eddy simulation (LES). Several scenarios with different ventilation rates are considered by taking the fire as a volumetric heat source. Results predicted by LES are compared with those from a k–? model. These include temperature fields, flame shape and the smoke movement pattern.

  8. Derivation of cardiac output and alveolar ventilation rate based on energy expenditure measurements in healthy males and females.

    PubMed

    Brochu, Pierre; Brodeur, Jules; Krishnan, Kannan

    2012-08-01

    Physiologically based pharmacokinetic modeling and occupational exposure assessment studies often use minute ventilation rates (VE), alveolar ventilation rates (VA) and cardiac outputs (Q) that are not reflective of the physiological variations encountered during the aggregate daytime activities of individuals from childhood to adulthood. These variations of VE, VA and Q values were determined for healthy normal-weight individuals aged 5-96?years by using two types of published individual data that were measured in the same subjects (n?=?902), namely indirect calorimetry measurements and the disappearance rates of oral doses of deuterium (²H) and heavy-oxygen (¹?O) in urine monitored by gas-isotope-ratio mass spectrometry. Arteriovenous oxygen content differences (0.051-0.082?ml of O? consumed ml?¹ of blood) and ratios of the physiological dead space to the tidal volume (0.232-0.419) were determined for oxygen consumption rates (0.157-0.806?l min?¹) required by minute energy expenditures ranging from 0.76 to 3.91?kcal min?¹. Generally higher values for the 2.5th up to the 99th percentile for VE (0.132-0.774?l kg?¹ min?¹, 4.42-21.69?l m?² min?¹), VA (0.093-0.553?l kg?¹ min?¹, 3.09-15.53?l m?² min?¹), Q (0.065-0.330?l kg?¹ min?¹, 2.17 to 9.46?l m?² min?¹) and ventilation-perfusion ratios (1.12-2.16) were found in children and teenagers aged 5-<16.5?years compared with older individuals. The distributions of cardiopulmonary parameters developed in this study should be useful in facilitating a scientifically sound characterization of the inter-individual differences in the uptake and health risks of lipophilic air pollutants, particularly as they relate to younger children. PMID:21365669

  9. Effects of gear box vibration and mass imbalance on the dynamics of multistage gear transmission

    NASA Technical Reports Server (NTRS)

    Choy, F. K.; Tu, Y. K.; Zakrajsek, J. J.; Townsend, D. P.

    1991-01-01

    The dynamic behavior of multistage gear transmission system, with the effects of gear-box-induced vibrations and rotor mass-imbalances is analyzed. The model method, using undamped frequencies and planar mode shapes, is used to reduce the degree-of-freedom of the system. The various rotor-bearing stages as well as lateral and torsional vibrations of each individual stage are coupled through localized gear-mesh-tooth interactions. Gear-box vibrations are coupled to the gear stage dynamics through bearing support forces. Transient and steady state dynamics of lateral and torsional vibrations of the geared system are examined in both time and frequency domain. A typical three-staged geared system is used as an example. Effects of mass-imbalance and gear box vibrations on the system dynamic behavior are presented in terms of modal excitation functions for both lateral and torsional vibrations. Operational characteristics and conclusions are drawn from the results presented.

  10. Pairing and crystallization of one-dimensional atomic mixtures with mass imbalance

    NASA Astrophysics Data System (ADS)

    Roscilde, Tommaso; Dalmonte, Marcello; Degli Esposti Boschi, Cristian

    2011-03-01

    We numerically investigate mass-imbalanced binary mixtures of hardcore bosons (or equivalently of fermions) loaded in one-dimensional optical lattices, with special focus on their instabilities towards the loss of first-order (one-body) coherence. We find a fundamental asymmetry between attractive and repulsive interactions. Attraction is found to always lead to pairing, and to pair crystallization for very strong mass imbalance and commensurate fillings. In the repulsive case away from half filling the two atomic components remain instead decoupled (and first-order coherent) over a large parameter range, and undergo crystallization or phase separation only for large mass-imbalance and/or strong interactions. This fundamental asymmetry is at odds with recent theoretical predictions, and can be tested directly via time-of-flight experiments on trapped cold atoms.

  11. SIRT1 deacetylase in SF1 neurons protects against metabolic imbalance

    PubMed Central

    Ramadori, Giorgio; Fujikawa, Teppei; Anderson, Jason; Berglund, Eric D.; Frazao, Renata; Michan, Shaday; Vianna, Claudia R.; Sinclair, David A.; Elias, Carol F.; Coppari, Roberto

    2011-01-01

    Summary Chronic feeding on high-calorie diets causes obesity and type 2 diabetes mellitus (T2DM), illnesses that affect hundreds of millions. Thus, understanding the pathways protecting against diet-induced metabolic imbalance is of paramount medical importance. Here we show that mice lacking SIRT1 in steroidogenic factor 1 (SF1) neurons are hypersensitive to dietary obesity owing to maladaptive energy expenditure. Also, mutant mice have increased susceptibility to develop dietary T2DM due to insulin resistance in skeletal muscle. Mechanistically, these aberrations arise, in part, from impaired metabolic actions of the neuropeptide orexin-A and the hormone leptin. Conversely, mice overexpressing SIRT1 in SF1 neurons are more resistant to diet-induced obesity and insulin resistance due to increased energy expenditure and enhanced skeletal muscle insulin sensitivity. Our results unveil important protective roles of SIRT1 in SF1 neurons against dietary metabolic imbalance. PMID:21907137

  12. Not enough there, too many here: understanding geographical imbalances in the distribution of the health workforce

    PubMed Central

    Dussault, Gilles; Franceschini, Maria Cristina

    2006-01-01

    Access to good-quality health services is crucial for the improvement of many health outcomes, such as those targeted by the Millennium Development Goals (MDGs) adopted by the international community in 2000. The health-related MDGs cannot be achieved if vulnerable populations do not have access to skilled personnel and to other necessary inputs. This paper focuses on the geographical dimension of access and on one of its critical determinants: the availability of qualified personnel. The objective of this paper is to offer a better understanding of the determinants of geographical imbalances in the distribution of health personnel, and to identify and assess the strategies developed to correct them. It reviews the recent literature on determinants, barriers and the effects of strategies that attempted to correct geographical imbalances, with a focus on empirical studies from developing and developed countries. An analysis of determinants of success and failures of strategies implemented, and a summary of lessons learnt, is included. PMID:16729892

  13. A Novel Algorithm for Imbalance Data Classification Based on Neighborhood Hypergraph

    PubMed Central

    Yu, Hong

    2014-01-01

    The classification problem for imbalance data is paid more attention to. So far, many significant methods are proposed and applied to many fields. But more efficient methods are needed still. Hypergraph may not be powerful enough to deal with the data in boundary region, although it is an efficient tool to knowledge discovery. In this paper, the neighborhood hypergraph is presented, combining rough set theory and hypergraph. After that, a novel classification algorithm for imbalance data based on neighborhood hypergraph is developed, which is composed of three steps: initialization of hyperedge, classification of training data set, and substitution of hyperedge. After conducting an experiment of 10-fold cross validation on 18 data sets, the proposed algorithm has higher average accuracy than others. PMID:25180211

  14. Scanogram for sagittal imbalance of the spine: low dose alternative for a safer diagnosis.

    PubMed

    Weisz, George M; Albury, W R; Houang, M D; Matucci-Cerinic, Marco

    2014-01-01

    The diagnosis of Fixed Sagittal Imbalance (FSI), previously known as Flat Back Syndrome, requires the measurement of spinal curvatures on a lateral radiograph in the standing position (C7-S1). It can be difficult to position a spastic patient, sometimes repeated exposure are required, at separate thoracic and lumbar levels, increasing the radiation dosage. CT Scanography is suggested as an alternative radiological diagnostic method since it is rapid to perform. The patient is comfortably positioned (horizontal) and it combines both prone and supine positions, therefore acting as a functional examination. This test was performed on 34 consecutive patients with fractured vertebrae (lumbar, dorsal) and with back pain persisting beyond the bone healing period. The functional scanogram was found to be accurate in diagnosing sagittal imbalances, but more importantly it offered reduction in radiation: in Entrance dose; in Effective dose and Absorption dose. Scanogram is therefore proposed as an alternative method for the diagnosis of FSI. PMID:25229500

  15. Quasiparticle trapping, Andreev level population dynamics, and charge imbalance in superconducting weak links

    NASA Astrophysics Data System (ADS)

    Zazunov, A.; Brunetti, A.; Yeyati, A. Levy; Egger, R.

    2014-09-01

    We present a comprehensive theoretical framework for the Andreev bound-state population dynamics in superconducting weak links. Contrary to previous works, our approach takes into account the generated nonequilibrium distribution of the continuum quasiparticle states in a self-consistent way. As application of our theory, we show that the coupling of the superconducting contact to environmental phase fluctuations induces a charge imbalance of the continuum quasiparticle population. This imbalance is due to the breaking of the left-right symmetry in the rates connecting continuum quasiparticles and the Andreev bound-state system, and causes a quasiparticle current on top of the Josephson current in a ring geometry. We evaluate the phase dependence of the quasiparticle current for realistic choices of the model parameters. Our theory also allows one to analyze the quantum coherent evolution of the system from an arbitrary initial state.

  16. A randomised crossover comparison of mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation by surf lifeguards in a manikin.

    PubMed

    Adelborg, K; Bjørnshave, K; Mortensen, M B; Espeseth, E; Wolff, A; Løfgren, B

    2014-07-01

    Thirty surf lifeguards (mean (SD) age: 25.1 (4.8) years; 21 male, 9 female) were randomly assigned to perform 2 × 3 min of cardiopulmonary resuscitation on a manikin using mouth-to-face-shield ventilation (AMBU LifeKey) and mouth-to-pocket-mask ventilation (Laerdal Pocket Mask). Interruptions in chest compressions, effective ventilation (visible chest rise) ratio, tidal volume and inspiratory time were recorded. Interruptions in chest compressions per cycle were increased with mouth-to-face-shield ventilation (mean (SD) 8.6 (1.7) s) compared with mouth-to-pocket-mask ventilation (6.9 (1.2) s, p < 0.0001). The proportion of effective ventilations was less using mouth-to-face-shield ventilation (199/242 (82%)) compared with mouth-to-pocket-mask ventilation (239/240 (100%), p = 0.0002). Tidal volume was lower using mouth-to-face-shield ventilation (mean (SD) 0.36 (0.20) l) compared with mouth-to-pocket-mask ventilation (0.45 (0.20) l, p = 0.006). No differences in inspiratory times were observed between mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation. In conclusion, mouth-to-face-shield ventilation increases interruptions in chest compressions, reduces the proportion of effective ventilations and decreases delivered tidal volumes compared with mouth-to-pocket-mask ventilation. PMID:24773395

  17. Patient-ventilator interactions. Implications for clinical management.

    PubMed

    Gilstrap, Daniel; MacIntyre, Neil

    2013-11-01

    Assisted/supported modes of mechanical ventilation offer significant advantages over controlled modes in terms of ventilator muscle function/recovery and patient comfort (and sedation needs). However, assisted/supported breaths must interact with patient demands during all three phases of breath delivery: trigger, target, and cycle. Synchronous interactions match ventilator support with patient demands; dyssynchronous interactions do not. Dyssynchrony imposes high pressure loads on ventilator muscles, promoting muscle overload/fatigue and increasing sedation needs. On current modes of ventilation there are a number of features that can monitor and enhance synchrony. These include adjustments of the trigger variable, the use of pressure versus fixed flow targeted breaths, and a number of manipulations of the cycle variable. Clinicians need to know how to use these modalities and monitor them properly, especially understanding airway pressure and flow graphics. Future strategies are emerging that have theoretical appeal but they await good clinical outcome studies before they become commonplace. PMID:24070493

  18. Ventilation Systems Operating Experience Review for Fusion Applications

    SciTech Connect

    Cadwallader, Lee Charles

    1999-12-01

    This report is a collection and review of system operation and failure experiences for air ventilation systems in nuclear facilities. These experiences are applicable for magnetic and inertial fusion facilities since air ventilation systems are support systems that can be considered generic to nuclear facilities. The report contains descriptions of ventilation system components, operating experiences with these systems, component failure rates, and component repair times. Since ventilation systems have a role in mitigating accident releases in nuclear facilities, these data are useful in safety analysis and risk assessment of public safety. An effort has also been given to identifying any safety issues with personnel operating or maintaining ventilation systems. Finally, the recommended failure data were compared to an independent data set to determine the accuracy of individual values. This comparison is useful for the International Energy Agency task on fusion component failure rate data collection.

  19. Distribution of ventilation in American alligator Alligator mississippiensis

    SciTech Connect

    Bickler, P.E.; Spragg, R.G.; Hartman, M.T.; White, F.N.

    1985-10-01

    The regional distribution of ventilation in the multicameral lung of spontaneously ventilating alligators (Alligator mississippiensis) was studied with TTXe scintigraphy. Frequent gamma camera images of TTXe washin and washout were obtained and processed to allow evaluation of regional ventilation. Washin of TTXe to equilibrium occurred in three to four breaths in anterior, central, and posterior compartments. Washin was most rapid in the posterior compartment and slowest in the anterior. The structure of the lungs and distribution of ventilation of inspired gas is consistent with the rapid radial spread of gas through a parallel arrangement of lung units surrounding the central intrapulmonary bronchus. Washout to equilibrium of TTXe from all compartments occurred within three to four breaths. This rapid washin and washout of gas to all parts of the lung stands in contrast to the lungs of turtles and snakes, in which the caudal air sacs are relatively poorly ventilated.

  20. [Myocardial perfusion scintigraphy - methods and fundamentals (author's transl)].

    PubMed

    Felix, R; Simon, H; Hedde, J P; Winkler, C

    1978-09-01

    Myocardial perfusion studies with labelled particles make a detailed analysis of the distribution of myocardial perfusion possible. Methodical and physiological fundamentals are described and the reliability of the method is shown by double radionuclide imaging. LAD-stenoses (greater than 70%) show a decreased activity in the distal areas of the LAD (on the average 36,5 +/- 10,3% in contrast to 59 +/- in normals). Mean local activity is 14,9 +/- 1,8% within scars. Scars and hemodynamically effective stenoses can be imaged with high sensitivity. Total defects (smaller than 15% of the activity maximum) correspond to a scar. A moderate reduction of uptake (15--50% of the activity maximum) does not allow any differentiation between scar and reversible diminution of perfusion. PMID:724528

  1. Testosterone biotransformation by the isolated perfused canine pancreas

    SciTech Connect

    Fernandez-del Castillo, C.; Diaz-Sanchez, V.; Varela-Fascinetto, G.; Altamirano, A.; Odor-Morales, A.; Lopez-Medrano, R.M.; Robles-Diaz, G. (Instituto Nacional de la Nutricion Salvador Zubiran, Mexico City (Mexico))

    1991-01-01

    There is strong evidence indicating that the pancreas is under the influence of sex steroid hormones, and that it may even participate in their biosynthesis and metabolism. In the present study, (3H)testosterone was perfused into the isolated canine pancreas, and measured in the effluent with several of its metabolites (5 alpha-dihydrotestosterone, androstenedione, and estradiol). Results show that testosterone is readily transformed by the canine pancreas. The main product found in the effluent is androstenedione. The testis and spleen were also perfused with (3H)testosterone and used as controls. In both cases, this hormone appeared mostly unchanged in the effluent as compared to the pancreatic perfusion (p less than 0.0001). From our data, we conclude that the canine pancreas has the capacity to transform sex steroid hormones, and could be considered an extragonadal site of sex steroid biosynthesis.

  2. Complete inhibition of creatine kinase in isolated perfused rat hearts

    SciTech Connect

    Fossel, E.T.; Hoefeler, H.

    1987-01-01

    Transient exposure of an isolated isovolumic perfused rat heart to low concentrations (0.5 mM) of perfusate-born iodoacetamide resulted in complete inhibition of creatine kinase and partial inhibition of glyceraldehyde-3-phosphate dehydrogenase in the heart. At low levels of developed pressure, hearts maintained mechanical function, ATP, and creatine phosphate levels at control values. However, iodoacetamide-inhibited hearts were unable to maintain control values of end diastolic pressure or peak systolic pressure as work load increased. Global ischemia resulted in loss of all ATP without loss of creatine phosphate, indicating lack of active creatine kinase. These results indicate that isovolumic perfused rat hearts are able to maintain normal function and normal levels of high-energy phosphates without active creatine kinase at low levels of developed pressure. /sup 31/P-NMR of the heart was carried out.

  3. Self-Consistent T-Matrix Approach to an Interacting Ultracold Fermi Gas with Mass Imbalance

    NASA Astrophysics Data System (ADS)

    Hanai, R.; Ohashi, Y.

    2014-04-01

    We investigate the superfluid phase transition in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover regime of an ultracold Fermi gas with mass imbalance. In the presence of mass imbalance, it is known that the strong-coupling Gaussian fluctuation theory, as well as the ordinary non-self-consistent T-matrix theory, that have been extensively used to clarify various BCS-BEC crossover physics in the mass-balanced case, unphysically give double valued superfluid phase transition temperature T c in the crossover region. In our previous paper (R. Hanai et al., J. Low Temp. Phys. 171:389, 2013), this difficulty was shown to be eliminated by an extended T-matrix approximation (ETMA). However, it was also found that this improved theory still gives vanishing T c in the BCS regime, when the mass imbalance ratio remarkably deviates from unity. In this paper, further extending ETMA to include higher order pairing fluctuations to the fully self-consistent T-matrix level, we clarify whether the vanishing T c obtained in ETMA is an intrinsic phenomenon or an artifact of this approximation. We show that the self-consistent T-matrix theory always gives a finite T c, even in the region where ETMA predicts the absence of superfluid instability. The key to the recovery of T c is found to be a consistent treatment with respect to the Fermi surface sizes of the light mass and heavy mass components, which ETMA lacks in. Since Fermi condensates with mass imbalance have been recently discussed in various systems, such as a 40K-6Li Fermi gas, exciton-polariton condensate, as well as color superconductivity, our results would be useful in constructing a reliable strong-coupling theory to examine physical properties of these novel Fermi superfluids.

  4. The effect of aerodynamic imbalance on a horizontal axis wind turbine

    SciTech Connect

    Borg, J.P.; Kirchhoff, R.H.

    1996-10-01

    In order to quantify aerodynamic imbalance effects on the measured loads of a horizontal axis wind turbine, HAWT, an algorithm was developed which is based on work done by de Vries and Manwell. Previous work was expanded to produce a Fortran code, Aero5, that can generate a time series of predicted aerodynamic forces acting on wind turbine blades. The National Renewable Energy Laboratory, NREL, 15 kW combined experiment test turbine was used as the baseline model for all of the tests. The configuration of the machine can be input such that each blade has a different pitch angle or relative azimuthal location and in so doing aerodynamic imbalance effects can be studied. Once the loads on the blades are determined for a specific configuration, the forces can be resolved into any reference frame so that time series data of quantities such as low speed shaft torque, bending moment, generator power, etc. can be predicted and compared to measured field data. During the simulation, input wind conditions were varied such that wind shear and cross wind were included. It was desired to know the effect of small pitch imbalance on machine loads specifically low speed shaft torque, LSST. It was found that a pitch imbalance as small as 2{degree} can result in a once per revolution (1P) oscillation in LSST with an amplitude as large as 60 N-m. It was also found that variations in relative blade azimuthal location had little effect on 1P oscillations in LSST. The results compare favorably to actual wind turbine field data and predictions made in previously papers by Kirchhoff.

  5. Tunneling Generation, Relaxation, and Tunneling Detection of Hole-Electron Imbalance in Superconductors

    Microsoft Academic Search

    M. Tinkham

    1972-01-01

    The theory of electron tunneling is extended to treat the generation and detection of an imbalance Q between electronlike and holelike quasiparticle populations in superconductors. The equilibration of injected high-energy quasiparticles owing to inelastic phonon processes is discussed, and it is shown that in tin, Q relaxes in tauQ~[Delta(0)Delta(T)](2×10-10) sec. It is also shown that even a small (~1%) anisotropy

  6. Secretion imbalance between tumour necrosis factor and its inhibitor in inflammatory bowel disease

    Microsoft Academic Search

    M Noguchi; N Hiwatashi; Z Liu; T Toyota

    1998-01-01

    Background—Tumour necrosis factor (TNF) ? and TNF-? are soluble ligands binding to TNF receptors with similar activities; soluble TNF receptors neutralise TNF activity by acting as inhibitors. Little is known about the cytokine\\/soluble receptor role in inflammatory bowel disease (IBD).Aims—To test the hypothesis that an imbalance in secretion between TNF and TNF inhibitors plays a role in gut inflammation in

  7. Patterns of Chromosomal Imbalances in Adenocarcinoma and Squamous Cell Carcinoma of the Lung

    Microsoft Academic Search

    Klaus Gellert; Martin Reichel; Thomas Cremer; Manfred Dietel; Thomas Ried; M. DI

    Comparative genomic hybridization was used to screen 25 adenocarci nomas and 25 squamous cell carcinomas of the lung for chromosomal imbalances. DNA copy number decreases common to both entities were observed on chromosomes ip, 3p, 4q, 5q, 6q, Sp, 9p, 13q, lSq, and 21q. Similarly, DNAgains were observed for chromosomes 5p, Sq, 11q13, l6p, 17q, and 19q. Adenocarcinomasshowed more frequently

  8. Drinking deep-sea water restores mineral imbalance in atopic eczema\\/dermatitis syndrome

    Microsoft Academic Search

    Y Hataguchi; H Tai; H Nakajima; H Kimata

    2005-01-01

    Objective:The effect of drinking deep-sea water on hair minerals was studied in patients with atopic eczema\\/dermatitis syndrome (AEDS). Study of hair minerals revealed an imbalance of essential minerals and an increase in toxic minerals in AEDS patients.Design:After drinking deep-sea water (Amami no Mizu) for 6 months in AEDS patients, hair minerals (essential minerals and toxic minerals), clinical evaluation of the

  9. SMAD signaling and redox imbalance cooperate to induce prostate cancer cell dormancy.

    PubMed

    Bui, Anh Thu; Laurent, Fanny; Havard, Maryline; Dautry, François; Tchénio, Thierry

    2015-04-18

    Metastasis involves the dissemination of single or small clumps of cancer cells through blood or lymphatic vessels and their extravasation into distant organs. Despite the strong regulation of metastases development by a cell dormancy phenomenon, the dormant state of cancer cells remains poorly characterized due to the difficulty of in vivo studies. We have recently shown in vitro that clonogenicity of prostate cancer cells is regulated by a dormancy phenomenon that is strongly induced when cells are cultured both at low cell density and in a slightly hypertonic medium. Here, we characterized by RT-qPCR a genetic expression signature of this dormant state which combines the presence of both stemness and differentiation markers. We showed that both TFG?/BMP signaling and redox imbalance are required for the full induction of this dormancy signature and cell quiescence. Moreover, reconstruction experiments showed that TFG?/BMP signaling and redox imbalance are sufficient to generate a pattern of genetic expression displaying all characteristic features of the dormancy signature. Finally, we observed that low cell density was sufficient to activate TGF?/BMP signaling and to generate a slight redox imbalance thus priming cells for dormancy that can be attained with a co-stimulus like hypertonicity, most likely through an increased redox imbalance. The identification of a dual regulation of dormancy provides a framework for the interpretation of previous reports showing a restricted ability of BMP signaling to regulate cancer cell dormancy in vivo and draws attention on the role of oxidative stress in the metastatic process. PMID:25706341

  10. The important role of temperature in BCS--Bose-Einstein condensation crossover phenomena with population imbalance

    NASA Astrophysics Data System (ADS)

    Chen, Qijin

    2007-03-01

    Any comparison between theory and experiment in the cold Fermi gases requires that one include the effects of non-zero temperature T. In this talk we show how to include finite T in a way which is compatible with the generalized BCS-like ground state, assumed in essentially all T=0 calculations of gases with population imbalance. We use a pairing fluctuation theory of BCS--Bose-Einstein condensation (BEC) based on a T-matrix formalism. Distinguishing this theory from strict mean-field theories is our self-consistent treatment of incoherent, finite-momentum pairs along with single fermions. This leads to a pseudogap in the fermion excitation spectrum at finite T which is necessary in order to arrive at physically meaningful transition temperatures Tc(p), where p is the polarization. We present phase diagrams in the p-T plane with variable scattering length, 1/kFa, and identify the regions where bulk superfluidity, normal phases and phase separation appears. For the trapped Fermi gases, we present particle density profiles for general 1/kFa as well as a detailed comparison with recent measurements at both MIT and Rice University. We find reasonably good agreement with these experimental data. 1. C.-C. Chien, Q.J. Chen, Y. He, and K. Levin, Intermediate temperature superfluidity in an atomic Fermi gas with population imbalance, Phys. Rev. Lett. 97, 090402 (2006). 2. Q.J. Chen, Y. He, C.-C. Chien, and K. Levin, Stability conditions and phase diagrams for two component Fermi gases with population imbalance, cond-mat/0608454; Phys. Rev. A 74, 06xxxx (2006). 3. C.-C. Chien, Q.J. Chen, Y. He, and K. Levin, Finite temperature effects in trapped Fermi gases with population imbalance, Phys. Rev. A 74, 021602(R) 2006.

  11. Steering neuronal growth cones by shifting the imbalance between exocytosis and endocytosis.

    PubMed

    Tojima, Takuro; Itofusa, Rurika; Kamiguchi, Hiroyuki

    2014-05-21

    Extracellular molecular cues guide migrating growth cones along specific routes during development of axon tracts. Such processes rely on asymmetric elevation of cytosolic Ca(2+) concentrations across the growth cone that mediates its attractive or repulsive turning toward or away from the side with Ca(2+) elevation, respectively. Downstream of these Ca(2+) signals, localized activation of membrane trafficking steers the growth cone bidirectionally, with endocytosis driving repulsion and exocytosis causing attraction. However, it remains unclear how Ca(2+) can differentially regulate these opposite membrane-trafficking events. Here, we show that growth cone turning depends on localized imbalance between exocytosis and endocytosis and identify Ca(2+)-dependent signaling pathways mediating such imbalance. In embryonic chicken dorsal root ganglion neurons, repulsive Ca(2+) signals promote clathrin-mediated endocytosis through a 90 kDa splice variant of phosphatidylinositol-4-phosphate 5-kinase type-1? (PIPKI?90). In contrast, attractive Ca(2+) signals facilitate exocytosis but suppress endocytosis via Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and cyclin-dependent kinase 5 (Cdk5) that can inactivate PIPKI?90. Blocking CaMKII or Cdk5 leads to balanced activation of both exocytosis and endocytosis that causes straight growth cone migration even in the presence of guidance signals, whereas experimentally perturbing the balance restores the growth cone's turning response. Remarkably, the direction of this resumed turning depends on relative activities of exocytosis and endocytosis, but not on the type of guidance signals. Our results suggest that navigating growth cones can be redirected by shifting the imbalance between exocytosis and endocytosis, highlighting the importance of membrane-trafficking imbalance for axon guidance and, possibly, for polarized cell migration in general. PMID:24849351

  12. Thoracolumbar imbalance analysis for osteotomy planification using a new method: FBI technique

    Microsoft Academic Search

    J. C. Le Huec; P. Leijssen; M. Duarte; S. Aunoble

    Introduction  Treatment of spine imbalance by posterior osteotomy is a valuable technique. Several surgical techniques have been developed\\u000a and proposed to redress the vertebral column in harmonious kyphosis in order to recreate correct sagittal alignment. Although\\u000a surgical techniques proved to be adequate, preoperative planning still is mediocre. Multiple suggestions have been proposed,\\u000a from cutting tracing paper to ingenious mathematical formulas and

  13. Personality and the effort-reward imbalance model of stress: Individual differences in reward sensitivity

    Microsoft Academic Search

    Amanda Allisey; John Rodwell; Andrew Noblet

    2012-01-01

    The Effort-Reward Imbalance (ERI) model comprises both situational components (i.e. effort and reward) and a person-specific component (overcommitment). The aims of this study were to investigate the role of theoretically and historically linked personality variables (i.e. overcommitment and Type A personality) within the ERI model and to expand and extend the ERI model by investigating the contribution of individual reward

  14. Real time perfusion and oxygenation monitoring in an implantable optical sensor

    E-print Network

    Subramanian, Hariharan

    2006-04-12

    Simultaneous blood perfusion and oxygenation monitoring is crucial for patients undergoing a transplant procedure. This becomes of great importance during the surgical recovery period of a transplant procedure when uncorrected loss of perfusion...

  15. Perfusion strategy for rosmarinic acid production by Anchusa officinalis.

    PubMed

    Su, W W; Lei, F; Su, L Y

    1993-09-20

    The production of an intracellular secondary metabolite rosmarinic acid (RA) by plant cell suspensions of Anchusa officinalis cultivated with intermittent medium exchange is investigated. Initially, a two-stage perfusion culture method was employed. After being cultured in the batch mode for ca. 6 days in B5 medium plus 3% sucrose, 1 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D), and 0.1 mg/L kinetin (2,4-D B5 medium), Anchusa culture was cultivated to high cell density by perfusion during the growth stage using a hormone-free Gamborg B5 medium supplemented with 6% sucrose. This was followed by a production stage, in which a complete medium exchange into B5 medium plus 3% sucrose and 0.25 mg/L naphthleneacetic acid (NAA) was conducted. The two-stage perfusion culture had a higher maximum culture RA concentration but a lower RA content per cell than the batch stock culture maintained in the 2,4-D B5 medium. Higher culture RA concentration was due primarily to high cell density. The high packed cell volume, however, seemed to reduce the synergistic effect of NAA on RA synthesis. Subsequently, a single-stage perfusion culture method was investigated. The best result was obtained by growing the culture in the batch mode for ca. 10 days using B5 medium supplemented with 3% sucrose and 0.25 mg/L NAA, followed by perfusing the culture with B5 medium plus 6% sucrose and 0.25 mg/L NAA at a constant perfusion rate of 0.1/day. A maximum cell dry weight of 35 g/L and a RA concentration of almost 4 g/L were achieved. This is the highest RA concentration ever reported in the Anchusa culture. PMID:18613136

  16. Can an energy balance model provide additional constraints on how to close the energy imbalance?

    PubMed Central

    Wohlfahrt, Georg; Widmoser, Peter

    2013-01-01

    Elucidating the causes for the energy imbalance, i.e. the phenomenon that eddy covariance latent and sensible heat fluxes fall short of available energy, is an outstanding problem in micrometeorology. This paper tests the hypothesis that the full energy balance, through incorporation of additional independent measurements which determine the driving forces of and resistances to energy transfer, provides further insights into the causes of the energy imbalance and additional constraints on energy balance closure options. Eddy covariance and auxiliary data from three different biomes were used to test five contrasting closure scenarios. The main result of our study is that except for nighttime, when fluxes were low and noisy, the full energy balance generally did not contain enough information to allow further insights into the causes of the imbalance and to constrain energy balance closure options. Up to four out of the five tested closure scenarios performed similarly and in up to 53% of all cases all of the tested closure scenarios resulted in plausible energy balance values. Our approach may though provide a sensible consistency check for eddy covariance energy flux measurements. PMID:24465072

  17. Strongly interacting atomic Fermi gases in a trap with mass and population imbalances at finite temperature

    NASA Astrophysics Data System (ADS)

    Wang, Jibiao; Guo, Hao; Chen, Qijin

    2012-02-01

    A great advantage of studying atomic Fermi gases is the easy tunability of multiple physical parameters, including interaction strength, mass and population imbalances, as well as species dependent trapping potential. Indeed, the mixture of ^6Li and ^40K gases has been of great interest, with and without population imbalance. In this talk, we will address the finite temperature phase diagrams of two component atomic Fermi gases with both mass and population imbalances in a trap, using a pairing fluctuation theory. We show that in certain parameter ranges, there exist intermediate temperature superfluids as well as phase separation with exotic sandwich-like shell structure with superfluid or pseudogapped normal state in the middle. We consider pairing strength over the entire range of BCS-BEC crossover. Our result is relevant to future experiment on mixtures of ^6Li and ^40K and possibly other Fermi atoms. References: H. Guo, C.-C. Chien, Q.J. Chen, Y. He, and K. Levin, Phys. Rev. A 80, 011601(R) (2009); C.-C. Chien, Q.J. Chen, Y. He, and K. Levin, Phys. Rev. Lett. 98, 110404 (2007); C.-C. Chien, Q.J. Chen, Y. He, and K. Levin, Phys. Rev. Lett. 97, 090402 (2006); Q.J. Chen, I. Kosztin, B. Janko, and K. Levin, Phys. Rev. Lett. 81, 4708 (1998).

  18. Finite Temperature Effects in Trapped Unitary Fermi Gases with Population Imbalance

    NASA Astrophysics Data System (ADS)

    Chien, Chih-Chun; Chen, Qijin; He, Yan; Levin, Katheryn

    2007-03-01

    We study the finite temperature T behavior of trapped Fermi gases in the unitary regime and in the presence of a population imbalance with polarization p. We obtain a phase diagram in the p - T plane, which establishes various superfluid and normal phases. Our theory, which is consistent with the standard T=0 calculations in the literature, incorporates the important effect of non-condensed pairs. These are essential in order to arrive at physically meaningful transition temperatures Tc(p). Moreover, as a result of these non-condensed pairs our T <=Tc profiles evolve from the well documented featureless behavior at p=0 to behavior which shows clear indications of the presence of a condensate at p !=0. We also show profiles and central densities in different regimes of the phase diagram, and detailed comparisons with recent experiments are presented, 1. C.-C. Chien, Q.J. Chen, Y. He, and K. Levin, Intermediate temperature superfluidity in an atomic Fermi gas with population imbalance, Phys. Rev. Lett. 97, 090402 (2006) 2. C.-C. Chien, Q.J. Chen, Y. He, and K. Levin, Finite temperature effects in trapped Fermi gases with population imbalance, Phys. Rev. A 74, 021602(R) 2006.

  19. Thermal imbalance in hot box apparatus and in-situ measurements

    SciTech Connect

    Bisiol, B.; Campanale, M.; Ponte, F. de; Moro, L. [Univ. degli Studi di Padova (Italy)

    1997-11-01

    Starting from the measurement principle for the determination of thermal resistance of a building element in the laboratory (guarded hot box method) and in-situ, possible testing errors are considered, in particular those due to temperature non-uniformity and imbalance between the metering and guard section. Almost all in-situ measurements are carried out in non-steady-state conditions, nevertheless imbalance problems are similar to those of such steady-state test methods as the guarded hot box. Temperature non-uniformity on the surfaces of the specimen generates an uncertainty in the definition of the surface temperature itself, but, as a consequence, there is an associated potential temperature imbalance. The scope of this work is to verify the semi-empirical expressions introduced in two documents of the European Committee for Standardization (CEN, Comite Europeen de Normalisation) with those for guarded hot plate apparatus, analytically obtained and experimentally verified by Woodside and those analytically obtained for guarded hot box apparatus. Next, the application of the CEN expression to assess the effect of temperature non-uniformities was checked: for this purpose some homogeneous and layered structures have been analyzed by the finite difference method.

  20. Alleviating Redox Imbalance Enhances 7-Dehydrocholesterol Production in Engineered Saccharomyces cerevisiae

    PubMed Central

    Liu, Duo; Zhou, Xiao; Yuan, Ying-Jin

    2015-01-01

    Maintaining redox balance is critical for the production of heterologous secondary metabolites, whereas on various occasions the native cofactor balance does not match the needs in engineered microorganisms. In this study, 7-dehydrocholesterol (7-DHC, a crucial precursor of vitamin D3) biosynthesis pathway was constructed in Saccharomyces cerevisiae BY4742 with endogenous ergosterol synthesis pathway blocked by knocking out the erg5 gene (encoding C-22 desaturase). The deletion of erg5 led to redox imbalance with higher ratio of cytosolic free NADH/NAD+ and more glycerol and ethanol accumulation. To alleviate the redox imbalance, a water-forming NADH oxidase (NOX) and an alternative oxidase (AOX1) were employed in our system based on cofactor regeneration strategy. Consequently, the production of 7-dehydrocholesterol was increased by 74.4% in shake flask culture. In the meanwhile, the ratio of free NADH/NAD+ and the concentration of glycerol and ethanol were reduced by 78.0%, 50.7% and 7.9% respectively. In a 5-L bioreactor, the optimal production of 7-DHC reached 44.49(±9.63) mg/L. This study provides a reference to increase the production of some desired compounds that are restricted by redox imbalance. PMID:26098102