We are investigating several alternate gas-switch designs for use in linear transformer drivers. To meet linear-transformer-driver (LTD) requirements, these air-insulated switches must be DC charged to 200 kV, be triggerable with a jitter of 5 ns or less, have very low prefire and no-fire rates ( $ 1 in 10 4 shots), and have a lifetime of at least several thousand shots. Since the switch inductance plays a significant role in limiting the rise time and peak current of the LTD circuit, the inductance needs to be as low as possible. The switches are required to conduct current pulses with $100-ns rise times and 20-80 kA peak currents, depending on the application. Our baseline switch, designed by the High Current Electronics Institute in Tomsk, Russia, is a six-stage switch with an inductance on the order of 115 nH that is insulated with 47-67 psia of air. We are also testing three smaller two-stage switches that have inductances on the order of 66-100 nH. The smaller switches are insulated with 92-252 psia of air.

SUMMARY BackgroundOesophageal lichen planus is an idiopathic inflammatory disorder characterized by significant oesophageal stricturing. Oesophageal lichen planus is a rare, difficult to diagnose, and likely an under recognized disease. As a result, there is no standardized approach to therapy and treatment strategies vary.

Several studies performed in alcoholics with advanced liver disease have demonstrated a positive correlation between the serum-ascites albumin gradient (SAAG) and measured portal venous pressure. A single study performed in 15 patients with exudative malignant ascites and 29 patients with alcoholic liver disease demonstrated that a SAAG of less than 1.1 was essentially diagnostic of a malignant origin of the ascites. In an effort to confirm and extend these observations to individuals with nonalcoholic liver disease, 24 patients with nonalcoholic liver disease and 11 with alcoholic liver disease undergoing orthotopic liver transplantation (OTLx) were studied. At the time of liver transplantation, each had their serum and ascitic fluid albumin levels determined, the gradient calculated, and their portal venous pressure (PVP) as well as the corrected portal venous pressure (PPc) measured directly. A significant correlation (r = 0.624) between the PPc and the SAAG was found in the 11 alcoholics (P less than 0.05). No such correlation existed for those with nonalcoholic liver disease (r = 0.398). Moreover, a SAAG less than 1.1 was found in three of nonalcoholics with cirrhosis in the absence of an abdominal malignancy. We conclude that (1) the SAAG and PPc are statistically related to each other in individuals with alcoholic liver disease but not in those with a nonalcoholic cause for cirrhosis, and (2) SAAG less than 1.1 is not diagnostic of abdominal malignancy but can occur in those with advanced nonmalignant hepatic disease.

Summary BACKGROUND Proton pump inhibitors (PPI) are inconsistently associated with osteoporotic fractures. Barrett’s oesophagus patients are treated with high PPI doses for prolonged periods, but there is limited data on the incidence of osteoporosis and fractures in them. AIM In this study, we aimed to estimate the incidence of (and risk factors for) low bone mass (osteoporosis and/or osteopenia) related fractures in a population-based Barrett’s oesophagus cohort. METHODS All subjects with Barrett’s oesophagus and a diagnosis of osteoporosis and fractures were identified using Rochester Epidemiology Project (REP) resources. The incidence rates of all and osteoporotic fractures in these subjects were compared to an age- and gender similar population in Olmsted County to determine standardized incidence ratios (SIR). Predictors were assessed using Cox proportional hazards models. RESULTS Five hundred and twenty-one patients were included [median (IQR) age 61(52, 72) years; three hundred ninety-eight (76%) men] of whom one hundred thirteen (21.7%) had fractures, and forty-six (8.8%) had osteoporotic fractures. The incidence of all fractures and osteoporotic fractures was comparable to that of an age- and gender- matched population (SIR 1.09; 95% CI 0.92–1.29: SIR 1.05; 95% CI 0.85–1.29). PPI use, dose or duration of use was not associated with osteoporotic fracture risk (HR 0.87; 95% CI 0.12–6.39). Independent risk factors for osteoporotic fractures included older age, female gender and higher co-morbidity index. CONCLUSIONS The incidence of osteoporotic fractures was not increased in Barrett’s oesophagus patients compared to the general population. Additionally, PPI use was not associated with increased fracture risk regardless of the duration of therapy or dose.

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