Research and development of liquid hydrogen (LH2) temperature monitoring system for marine applications

Monitoring the temperature in liquid hydrogen (LH₂) storage tanks on ships is important for the safety of maritime navigation. In addition, accurate temperature measurement is also required for commercial transactions. Temperature and pressure define the density of liquid hydrogen, which is directly linked to trading interests. In this study, we developed and tested a liquid hydrogen temperature monitoring system that uses platinum resistance sensors with a nominal electrical resistance of approximately 1000 Ω at room temperature, PT-1000, for marine applications. The temperature measurements were carried out using a newly developed temperature monitoring system under different pressure conditions. The measured values are compared with a calibrated reference PT-1000 resistance thermometer. We confirm a measurement accuracy of ±50 mK in a pressure range of 0.1 MPa–0.5 MPa.     

Breakdown of oil films and formation of residual films

The breakdown processes of oil films under quasi-static loading have been investigated by using a newly developed steel-oil-mercury system. The relationship between the thickness and breakdown ratio of a hexadecane film is represented by a single master curve independently of the indentation speed, indentation load, and temperature. The master curve shows that the breakdown process of hexadecane includes two stages; one is the decrement of the thickness without breakdown and the other is the decrement of the thickness with a drastic progress of breakdown. By solving a small amount of fatty acid in hexadecane, the thickness increases and the breakdown ratio decreases noticeably; a multilayer residual film supporting normal load is formed between two metal surfaces. Experiments at different temperatures reveal a negative relationship between the temperature and thickness of residual film, which indicates that the residual film is organized by physical interaction rather than chemical interaction. At least under a lower concentration, the residual film appears to consist of not only fatty acid molecules but also hexadecane molecules.     

Efficacy of interferons in treating children with chronic hepatitis C

Twenty-two children with chronic hepatitis serologically positive for hepatitis C virus (HCV) were treated with interferon-alpha (IFN-alpha). Liver biopsy showed chronic active hepatitis in 13 and chronic persistent hepatitis in 9 patients. A sustained clearance of HCV was observed in 8/22 children 12 months after the administration of IFN-alpha for 26 weeks, associated with normalization of HCV core antibody. Of these eight patients six had HCV genotype III and two HCV genotype II or IV. Hepatitis relapsed in seven other patients after completion of IFN-alpha with an increase in HCV core antibody titre, five with HCV genotype II, and two with HCV genotype III or IV. A second course of IFN-alpha suppressed the reactivation of HCV in all seven patients. Three of seven responders who relapsed after the first course remained negative for HCV RNA 12 months after their second course of IFN-alpha. However, the remaining four patients with HCV genotype II again relapsed after completing their second course of IFN-alpha. Seven children with the HCV genotype II resistant to IFN, including 8 weeks of IFN-beta administration, and showed no significant reduction in HCV core antibody titre. CONCLUSION: The genotype of HCV (III) and a reduction in the core antibody titre appear to be useful parameters for predicting the response to IFN-alpha therapy.     

A novel brain-derived member of the epidermal growth factor family that interacts with ErbB3 and ErbB4

The availability of an analgesic compound devoid of the side effects associated with the commonly used opioid and nonsteroidal antiinflammatory drugs would be useful during the perioperative period. Although adenosine has analgesic and anesthetic-sparing properties, it also produces dose-dependent cardiovascular depression. Inhibitors of adenosine kinase may be able to provide analgesia without producing acute cardiovascular or respiratory depression. This preliminary study investigated the effects of a novel adenosine kinase-inhibiting drug, GP683, on the minimum alveolar anesthetic concentration (MAC) of desflurane in dogs. Seven mongrel dogs were administered one of three different GP683 dose regimens (or the solvent) by intravenous infusion on separate occasions according to a cross-over study design. After determining the baseline desflurane MAC value, GP683 was infused at 75, 150, or 300 microg x kg(-1) x min(-1) for 5 min as a loading dose, followed by 15, 30, or 60 microg x kg(-1) x min(-1) for an additional 85 min to maintain a stable plasma drug level. The desflurane MAC was redetermined 30-90 min after starting the study drug or vehicle infusion, and 30-90 min and 120-180 min after termination of the infusion. Cardiovascular variables and plasma concentrations of GP683 were determined at specific intervals before, during, and after the MAC determinations. The three GP683 dose regimens produced 22%, 31%, and 50% decreases in the desflurane MAC, respectively. In addition, there was good correlation between the decrease in desflurane MAC and the plasma GP683 concentration (r = -0.78). Although the mean arterial pressure (MAP) was decreased up to 25% by the highest infusion rate of GP683, adjustments in the desflurane concentration to an equi-MAC value resulted in normalization of the MAP values. Furthermore, GP683 produced no changes in heart rate. In conclusion, the adenosine kinase-inhibiting drug, GP683, produced dose-dependent decreases in the desflurane MAC of dogs without producing untoward hemodynamic changes. IMPLICATIONS: An investigational drug (GP683) that can increase the levels of an important endogenous substance in the body (adenosine) has been found to decrease the anesthetic requirement in dogs without producing adverse effects on the cardiovascular system.     

Acetazolamide challenge and technetium-99m-ECD versus iodine-123-IMP SPECT in chronic occlusive cerebrovascular disease

We compared the acetazolamide challenge test using 99mTc-ECD SPECT and 123I-IMP SPECT images in patients with chronic occlusive cerebrovascular disease. We also evaluated the usefulness of linearization correction for acetazolamide challenge test of 99mTc-ECD SPECT. METHODS: Twenty patients with unilateral chronic occlusive cerebrovascular disease (10 patients had middle cerebral arterial lesion and 10 had internal carotid lesion) were included in the study. Split-dose (a dose fractioning was 1:2), and sequential SPECT technique was used for 99mTc-ECD SPECT studies while only acetazolamide challenge test studies for 123I-IMP SPECT were performed. Permeability surface area product model (PS model) and back-diffusion model (Lassen's correction) were used for linearization correction of acetazolamide challenge with 99mTc-ECD SPECT. RESULTS: Six of 16 patients with reduced vasodilatory capacity in 123I-IMP SPECT were underestimated by 99mTc-ECD SPECT acetazolamide challenge test. Relative ECD uptake normalized by cerebellar uptake compared with IMP uptake showed a nonlinear relationship, indicating relatively less uptake in high flow range. The underestimations of limited vasodilatory capacity observed in 99mTc-ECD SPECT without linearization correction was modified by linearization algorithm. However, the effect of correction based on PS model was superior than that of Lassen's correction. The corrected 99mTc-ECD uptake ratio, based on PS model, and IMP uptake ratio demonstrated a better linear relationship than that of Lassen's correction. CONCLUSION: Technetium-99m ECD SPECT corrected based on the PS model is a better method of linearization for evaluating cerebrovascular reserve using acetazolamide challenge.     

Preparation of polyimide-epoxy composites

The formation of a three dimensional network of crosslinked epoxy leads all unmodified epoxies to have inherent brittleness and relatively low degradation temperatures. Polyimides, on the other hand, are widely used for applications that require high degrees of flexibility and thermal resistance. Here, we have focused on the preparation of epoxy systems cured with polyamic acids instead of traditional amino-group-containing hardening agents. The cure behavior and potential reaction mechanisms of EPON 828 resin and polyamic acid mixtures were evaluated by DSC and TGA. Thermal analysis showed a complex reaction sequence taking place in the mixture and also determined the extent of reaction of the polyamic acid with itself and the competitive reaction of the polyamic acid with the epoxy. The compositions of the mixtures were varied to see the dependence of the cure behavior on component concentrations. Solutions of the two components did not phase separate and also phase separation was not apparent either optically or microscopically in the cured samples. This phase behavior was attributed to a unique in situ reaction. A novel solvent system for the polyamic acid precursor was also used.     

Hepatitis GB virus C genome in the serum of aplastic anaemia patients receiving frequent blood transfusions

GB virus C (GBV-C) RNA was detected in five of 18 patients with aplastic anaemia who had received blood transfusions, whereas it was not detected in eight patients who had not received any transfusions. Antibody against hepatitis C virus (anti-HCV) was detected in nine patients in the transfusion group, compared with one of eight who had not received any transfusions. Therefore, the route of transmission of both GBV-C and HCV in these patients appeared to have been multiple blood transfusion. Since all of the GBV-C RNA-positive patients harboured anti-HCV, GBV-C seems to frequently superinfect with HCV. Neither GBV-C nor HCV is likely to have been a causative agent of the anaemia in the cases examined.     

Question hard, answer simply: A comment on Storms et al. (2003).

It seems clear that, for whatever reasons, the dementia of the Alzheimer type patient group (as well as other patient groups) exhibits behavior that is different from the normal control group. G. Storms, T. Dirikx, J. Saerens, S. Verstraeten, and P. P. De Deyn (2003) rightfully argue that the observed behavior (similarity judgments) does not tell us the source (cause) of the differences between the 2 groups. Rather, the focus of the study should be placed more on finding the ways the 2 groups are different. They also point out various methodological problems in some of the previous attempts to characterize the nature of the differences. Further methodological issues in G. Storms et al.'s study are examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intramolecular triplet energy migration in poly(2-vinylnaphthalene) and poly(naphthylalkyl methacrylate)s in solid solution: Effects of side chain length

Summary The effect of side chain length on intramolecular triplet energy migration of naphthalene containing polymers was investigated by a delayed fluorescence (DF) spectroscopy for the solid solution of the polymers. The degree of triplet energy migration depends strongly on whether the chromophores are directly attached to the main chain or not.