oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 11 )

2019 ( 85 )

2018 ( 66 )

2017 ( 90 )

Custom range...

Search Results: 1 - 10 of 32312 matches for " Peter Frykholm "
All listed articles are free for downloading (OA Articles)
Page 1 /32312
Display every page Item
Optimizing positive end-expiratory pressure by oscillatory mechanics minimizes tidal recruitment and distension: an experimental study in a lavage model of lung injury
Emanuela Zannin, Raffaele L Dellaca, Peter Kostic, Pasquale P Pompilio, Anders Larsson, Antonio Pedotti, Goran Hedenstierna, Peter Frykholm
Critical Care , 2012, DOI: 10.1186/cc11858
Abstract: We studied six pigs in which lung injury was induced by bronchoalveolar lavage. The animals were ventilated with a tidal volume of 6 ml/kg. Forced oscillations at 5 Hz were superimposed on the ventilation waveform. Pressure and flow were measured at the tip and at the inlet of the endotracheal tube respectively. Respiratory system reactance (Xrs) was computed from the pressure and flow signals and expressed in terms of oscillatory elastance (EX5). Positive end-expiratory pressure (PEEP) was increased from 0 to 24 cm H2O in steps of 4 cm H2O and subsequently decreased from 24 to 0 in steps of 2 cm H2O. At each PEEP step CT scans and EX5 were assessed at end-expiration and end-inspiration.During deflation the relationship between both end-expiratory and end-inspiratory EX5 and PEEP was a U-shaped curve with minimum values at PEEP = 13.4 ± 1.0 cm H2O (mean ± SD) and 13.0 ± 1.0 cm H2O respectively. EX5 was always higher at end-inspiration than at end-expiration, the difference between the average curves being minimal at 12 cm H2O. At this PEEP level, CT did not show any substantial sign of intra-tidal recruitment/derecruitment or expiratory lung collapse.Using FOT it was possible to measure EX5 both at end-expiration and at end-inspiration. The optimal PEEP strategy based on end-expiratory EX5 minimized intra-tidal recruitment/derecruitment as assessed by CT, and the concurrent attenuation of intra-tidal variations of EX5 suggests that it may also minimize tidal mechanical stress.Current strategies for mechanical ventilation of patients with acute respiratory distress syndrome (ARDS) include low tidal volumes and increased positive end-expiratory pressure (PEEP) [1]. The physiological basis for these strategies is still under debate, but may involve the reduction of forces of stress and strain on the parenchyma [2]. The ARDSNet protocol is a table-based approach of setting PEEP and the fraction of inspired oxygen (FIO2) levels to achieve an oxygenation target [3]. The a
Positive end-expiratory pressure optimization with forced oscillation technique reduces ventilator induced lung injury: a controlled experimental study in pigs with saline lavage lung injury
Peter Kostic, Emanuela Zannin, Marie Andersson Olerud, Pasquale P Pompilio, G?ran Hedenstierna, Antonio Pedotti, Anders Larsson, Peter Frykholm, Raffaele L Dellaca
Critical Care , 2011, DOI: 10.1186/cc10236
Abstract: 17 pigs, in which acute lung injury (ALI) was induced by saline lavage, were studied. Animals were randomized into two groups: in the first PEEP was titrated according to Xrs (FOT group), in the control group PEEP was set according to the ARDSNet protocol (ARDSNet group). The duration of the trial was 12 hours. In both groups recruitment maneuvers (RM) were performed every 2 hours, increasing PEEP to 20 cmH2O. In the FOT group PEEP was titrated by monitoring Xrs while PEEP was reduced from 20 cmH2O in steps of 2 cmH2O. PEEP was considered optimal at the step before which Xrs started to decrease. Ventilatory parameters, lung mechanics, blood gases and hemodynamic parameters were recorded hourly. Lung injury was evaluated by histopathological analysis.The PEEP levels set in the FOT group were significantly higher compared to those set in the ARDSNet group during the whole trial. These higher values of PEEP resulted in improved lung mechanics, reduced driving pressure, improved oxygenation, with a trend for higher PaCO2 and lower systemic and pulmonary pressure. After 12 hours of ventilation, histopathological analysis showed a significantly lower score of lung injury in the FOT group compared to the ARDSNet group.In a lavage model of lung injury a PEEP optimization strategy based on maximizing Xrs attenuated the signs of ventilator induced lung injury. The respiratory system reactance measured by FOT could thus be an important component in a strategy for delivering protective ventilation to patients with ARDS/acute lung injury.Mechanical ventilation is a mainstay of intensive care for patients with acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). A ventilation strategy based on tidal volumes of 6 ml.kg-1 and pre-defined positive end-expiratory pressure (PEEP) settings has been shown to reduce morbidity and mortality probably due to less ventilation-induced lung injury (VILI) [1-3]. Various protocols using higher levels of PEEP in combination
Natural Rights, Morality, and the Law  [PDF]
Drum Peter
Beijing Law Review (BLR) , 2011, DOI: 10.4236/blr.2011.21004
Abstract: It is argued that despite attempts to discount the importance of natural rights for morality, they are fundamental to it; therefore, so too are natural rights to the legitimacy of the law.
Price Stability and the Growth Maximizing Rate of Inflation for Ghana  [PDF]
Peter Quartey
Modern Economy (ME) , 2010, DOI: 10.4236/me.2010.13021
Abstract: Monetary policy in Ghana, which is typical of many central banks, over the years, has focused on ensuring price stability or low inflation. The aim of the policy of price stability is to provide a stable environment for real sector activities to flourish. However, the outcome of the policy on real sector activities has not been subjected to any empirical investigation and this forms the focus of the study. For instance, the Central Bank has focused on single digit inflation and whether such a low rate is growth maximizing is yet to be ascertained. The study therefore investigates the revenue maximizing and the ‘growth maximizing’ rate of inflation for Ghana using data from Bank of Ghana and WDI. The study finds that economic performance is higher under low inflation era than when inflation is high. It also established the revenue maximizing rate of inflation using the Laffer curve approach is lower than the growth maximizing rate of inflation. Also, from the results, it can be deduced that the single digit inflation target set by the Central bank is not growth maximizing.
Aristotle’s Definition of Place and of Matter  [PDF]
Peter Drum
Open Journal of Philosophy (OJPP) , 2011, DOI: 10.4236/ojpp.2011.11006
Abstract: The accuracy of Aristotle’s definition of place is defended in terms of his form-matter theory. This theory is in turn defended against the objectionable notion that it entails matter is ultimately characterless.
Adapted Caussinus-Mestre Algorithm for Networks of Temperature series (ACMANT)  [PDF]
Peter Domonkos
International Journal of Geosciences (IJG) , 2011, DOI: 10.4236/ijg.2011.23032
Abstract: Any change in technical or environmental conditions of observations may result in bias from the precise values of observed climatic variables. The common name of these biases is inhomogeneity (IH). IHs usually appear in a form of sudden shift or gradual trends in the time series of any variable, and the timing of the shift indicates the date of change in the conditions of observation. The seasonal cycle of radiation intensity often causes marked seasonal cycle in the IHs of observed temperature time series, since a substantial portion of them has direct or indirect connection to radiation changes in the micro-environment of the thermometer. Therefore the magnitudes of temperature IHs tend to be larger in summer than in winter. A new homogenisation method (ACMANT) has recently been developed which treats in a special way the seasonal changes of IH-sizes in temperature time series. The ACMANT is a further development of the Caussinus-Mestre method, that is one of the most effective tool among the known homogenising methods. The ACMANT applies a bivariate test for searching the timings of IHs, the two variables are the annual mean temperature and the amplitude of seasonal temperature-cycle. The ACMANT contains several further innovations whose efficiencies are tested with the benchmark of the COST ES0601 project. The paper describes the properties and the operation of ACMANT and presents some verification results. The results show that the ACMANT has outstandingly high performance. The ACMANT is a recommended method for homogenising networks of monthly temperature time series that observed in mid- or high geographical latitudes, because the harmonic seasonal cycle of IH-size is valid for these time series only.
Random but System-Wide Unique Unlinkable Parameters  [PDF]
Peter Schartner
Journal of Information Security (JIS) , 2012, DOI: 10.4236/jis.2012.31001
Abstract: When initializing cryptographic systems or running cryptographic protocols, the randomness of critical parameters, like keys or key components, is one of the most crucial aspects. But, randomly chosen parameters come with the intrinsic chance of duplicates, which finally may cause cryptographic systems including RSA, ElGamal and Zero-Knowledge proofs to become insecure. When concerning digital identifiers, we need uniqueness in order to correctly identify a specific action or object. Unfortunately we also need randomness here. Without randomness, actions become linkable to each other or to their initiator’s digital identity. So ideally the employed (cryptographic) parameters should fulfill two potentially conflicting requirements simultaneously: randomness and uniqueness. This article proposes an efficient mechanism to provide both attributes at the same time without highly constraining the first one and never violating the second one. After defining five requirements on random number generators and discussing related work, we will describe the core concept of the generation mechanism. Subsequently we will prove the postulated properties (security, randomness, uniqueness, efficiency and privacy protection) and present some application scenarios including system-wide unique parameters, cryptographic keys and components, identifiers and digital pseudonyms.
Enlarged cauda equina nerve roots in Cerebrotendinous Xanthomatosis  [PDF]
Peter Kalina
Open Journal of Clinical Diagnostics (OJCD) , 2011, DOI: 10.4236/ojcd.2011.13006
Abstract: CXT is a rare inherited autosomal recessive lipid storage disease due to the impaired metabolic pathway of cholesterol secondary to a deficiency in 27- sterol hydroxylase, an enzyme in the synthesis of chenodeoxycholic acid (CDCA), a primary bile acid. Abnormal bile acid synthesis leads to elevated plasma Cholestanol (a derivative of cholesterol) accumulation, especially in the lens, central nervous system (CNS) and tendons.
Spinal Cord Compression by Thoracic Vertebral Hemangioma—A Case Report  [PDF]
Peter Kalina
Open Journal of Medical Imaging (OJMI) , 2012, DOI: 10.4236/ojmi.2012.21005
Abstract: A 68 year old with lower extremity numbness, vibratory sensation loss, coldness and burning of his feet, unsteady gait, frequent falls and a sensory level had an MRI demonstrating aT7 and T8 vertebral body/posterior element lesion with epidural extension, cord compression and foraminal extension (Figures 1-5). Decompressive laminectomy/resection confirmed vertebral hemangioma, a common benign neoplasm that typically remains asymptomatic, found incidentally in 10% of the population. Progressive vertebral body hemangiomas may cause cord or nerve root compression due to epidural tumor extension, expanded bone, hematoma or fracture. Radiographs demonstrate course vertical striations caused by thick trabeculae. CT in indolent lesions demonstrates fat density while compressive lesions demonstrate soft tissue density. Indolent lesions follow fat signal on MRI; symptomatic lesions are T1 isointense/T2 hyperintense. Work-up for aggressive hemangiomas includes angiography to determine vascularity, identify feeding/draining vessels and identify blood supply to the cord. Biopsy helps differentiate hemangioma, lymphoma, myeloma or metastasis. Management of symptomatic hemangiomas includes vertebroplasty for pain, radiation for pain, compression or pre-op and decompressive laminectomy for epidural disease. Embolization of feeding vessels may be performed pre-op or may be curative. Hemangioma causing cord compression and neurologic symptoms by extraosseous extension is much less common than benign hemangioma. Imaging features may suggest potential for progression.
Tay-Sachs and French Canadians: A Case of Gene-Culture Co-evolution?  [PDF]
Peter Frost
Advances in Anthropology (AA) , 2012, DOI: 10.4236/aa.2012.23016
Abstract: Tay-Sachs, an inherited neurological disorder, is unusually common among French Canadians from eastern Quebec. Two alleles are responsible, one being specific to the north shore of the St. Lawrence and the other to the south shore. This pattern of convergent evolution suggests the presence of a selection pressure limited to eastern Quebec. Both alleles probably arose after the British conquest of Quebec in 1759 or at least were uncommon previously. To explain the high incidence of Tay-Sachs among Ashkenazi Jews, some authors have invoked heterozygote advantage, i.e., heterozygous individuals enjoy a higher rate of neuronal growth, and thus greater learning capacity, without the neurological deterioration of homozygous individuals. Such an advantage would have helped Ashkenazim perform the mental effort required for work in trade and crafts. A similar situation may have developed in eastern Quebec, where the relative scarcity of British and American merchants made it easier for French Canadians to enter occupations that required literacy, numeracy, and future time orientation.
Page 1 /32312
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.