Impulse Correlation for Partially Filled Detonation Tubes

The effect of nozzles on the impulse obtained from a detonation tube of circular cross section has been the focus of many experimental and numerical studies. In these cases, the simplified detonation tube is closed at one end (forming the thrust surface) and open at the other end, enabling the attachment of an extension. A flowfield analysis of a detonation tube with an extension requires considering unsteady wave interactions making analytical and accurate numerical predictions difficult (especially in complicated extension geometries). To predict the impulse obtained from a detonation tube with an extension (considered a partially filled detonation tube), we utilize data from other researchers to generate a partial-fill correlation

The Characterization of Epstein-Barr Virus Infected B Cells in the Peripheral Blood of Pediatric Solid Organ Transplant Recipients with Elevated Viral Loads

Epstein-Barr virus (EBV) has infected 95% of the adult population. Yet, EBV stays as a harmless passenger in infected B-cells of nearly every host. EBV depends on a careful balance between the immune system and the virus that becomes evident when the host is immunocompromised. In such individuals, EBV can manifest as one of many associated malignancies. In children who have undergone solid organ transplantation, EBV-driven post-transplant lymphoproliferative disease (PTLD) can cause significant morbidity and mortality. We examined EBV-infected cells in non-diseased pediatric transplant recipients with elevated viral loads in their peripheral blood. Examination of high EBV genome copy cells in high load patients with a combined fluorescent in situ hybridization and immunofluorescence procedure demonstrated that the majority of high copy cells had no discernible expression of immunoglobulin on the surface (Ig-null cells). Such cells are lacking the crucial survival signal provided by an intact BCR and should not survive in the circulation. By flow cytometry, high load patients were shown to have the highest percentage of Ig-null cells in their peripheral blood; those with low viral loads and non-detectable viral loads had lower percentages. The phenotype of Ig-null cells was shown to differ from the resting memory B2 phenotype of normal latently infected B cells, with variable expression of CD20, CD40, and HLA Class I and II. Sorting Ig-null cells from the peripheral blood of high load carriers further demonstrated that in all patients examined, a large portion of the viral load was carried in the Ig-null compartment. Virus was also detected in the Ig-null, CD20- and HLA Class I- compartment, with a variable enrichment of the viral load in these compartments from patient to patient. Ig-null cells have been reported in the tumors of other EBV-associated malignancies, including PTLD, but never in the peripheral blood or in a non-disease state. This study has public health relevance because PTLD carries significant morbidity and mortality to transplant recipients; the presence in the blood of aberrant Ig-null cells which should have followed a program of apoptosis might be a risk factor for the development of PTLD or another EBV-associated disease

New multiplexing scheme for monitoring fiber optic Bragg grating sensors in the coherence domain

A new multiplexing scheme for monitoring fiber optic Bragg gratings in the coherence domain has been developed. Grating pairs with different grating distances are distributed along a fiber line, and interference between their reflections is monitored with a scanning Michelson interferometer. The Bragg wavelength of the individual sensor elements is determined from the interference signal frequency

Glutathione treatment protects the rat liver against injury after warm ischemia and Kupffer cell activation

Background/Aim: The generation of reactive oxygen species by activated Kupffer cells (KC) may contribute to reperfusion injury of the liver during liver transplantation or resection. The aim of our present studies was to investigate (1) prevention of hepatic reperfusion injury after warm ischemia by administration of the antioxidant glutathione (GSH) and (2) whether GSH confers protection through influences on KC toxicity. Methods: Isolated perfused rat livers were subjected to 1 h of warm ischemia followed by 90 min of reperfusion without (n = 5) or with GSH or catalase (n = 4-5 each). Selective KC activation by zymosan (150 mug/ml) in continuously perfused rat livers was used to investigate KC-related liver injury. Results: Postischemic infusion of 0.1, 0.5, 1.0 and 2.0 mM GSH, but not 0.05 mM GSH prevented reperfusion injury after warm ischemia as indicated by a marked reduction of sinusoidal LDH efflux by up to 83 +/- 13% (mean +/- SD; p < 0.05) and a concomitant significant improvement of postischemic bile flow by 58 +/- 27% (p < 0.05). A similar protection was conveyed by KC blockade with gadolinium chloride indicating prevention of KC-related reperfusion injury by postischemic GSH treatment. Postischemic treatment with catalase (150 U/ml) resulted in a reduction of LDH efflux by 40 +/- 9% (p < 0.05). Accordingly, catalase as well as GSH (0.1-2.0 mM) nearly completely prevented the increase in LDH efflux following selective :KC activation by zymosan in continously perfused rat livers. Conclusion: Postischemic administration of GSH protects the liver against reperfusion injury after warm ischemia. Detoxification of KC-derived hydrogen peroxide seem to be an important feature of the protective mechanisms. Copyright (C) 2002 S. Karger AG, Basel

GSH Attenuates Organ Injury and Improves Function after Transplantation of Fatty Livers

Ischemia-reperfusion injury (IRI) is increased after transplantation of steatotic livers. Since those livers are increasingly used for transplantation, protective strategies must be developed. Reactive oxygen species (ROS) play a key role in hepatic IRI. In lean organs, glutathione (GSH) is an efficient scavenger of ROS, diminishing IRI. The aim of this study was to evaluate whether GSH also protects steatotic allografts from IRI following transplantation. Fatty or lean livers were explanted from 10-week-old obese or lean Zucker rats and preserved (obese 4 h, lean 24 h) in hypothermic University of Wisconsin solution. Arterialized liver transplantation was then performed in lean syngeneic Zucker rats. Recipients of fatty livers were treated with GSH (200 mu mol/h/kg) or saline during reperfusion (2 h, n = 5). Parameters of hepatocellular damage and bile flow were measured. Transplantation of steatotic livers enhanced early reperfusion injury compared to lean organs as measured by increased aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase plasma levels. Bile flow was also reduced in steatotic grafts. Intravenous administration of GSH effectively decreased liver damage in fatty allografts and resulted in improved bile flow. Intravenous application of GSH effectively reduces early IRI in steatotic allografts and improves recovery of these marginal donor organs following transplantation. Copyright (C) 2010 S. Karger AG, Base

Edaq530: a transparent, open-end and open-source measurement solution in natural science education

We present Edaq530, a low-cost, compact and easy-to-use digital measurement solution consisting of a thumb-sized USB-to-sensor interface and a measurement software. The solution is fully open-source, our aim being to provide a viable alternative to professional solutions. Our main focus in designing Edaq530 has been versatility and transparency. In this paper, we shall introduce the capabilities of Edaq530, complement it by showing a few sample experiments, and discuss the feedback we have received in the course of a teacher training workshop in which the participants received personal copies of Edaq530 and later made reports on how they could utilise Edaq530 in their teaching