On Inheritance of Quadratic First Integral of Linear System via Runge-Kutta Methods

This paper deals with a condition for any quadratic homogeneous first integral of an arbitrary linear system with constant coefficients to be conserved by a discrete system obtained by applying Runge-Kutta methods

Symplectic Runge-Kutta Methods from the Viewpoint of Symmetry

The Weinstein generating function is introduced in order to represent a symplectic mapping, and it is shown that the representation is closely related to a certain symplectic Runge-Kutta method. Furthermore, the symmetry property is characterized by means of the generating function, and in relation to the symmetry, several stabilities intrinsic to linearly symplectic Runge-Kutta methods are studied. 2000 Mathematics Subject Classification. Primary 65L06; Secondary 70H0

A Topic of Quadratic First Integral of Linear Symplectic System

It is shown that every quadratic first integral of a linear symplectic system is expressed as a linear combination of quadratic forms constructed from generalized eigenvectors corresponding to four coupled eigenvalues

Occurrence of thiamin pyrophosphate-dependent 2-oxoglutarate decarboxylase in mitochondria of Euglena gracilis

Abstract2-Oxoglutarate decarboxylase which catalyzes the conversion of 2-oxoglutarate into succinate semialdehyde occurs in mitochondria of Euglena gracilis which lacks a 2-oxoglutarate dehydrogenase complex. The enzyme reaction required thiamin pyrophosphate, MgCl2, 2-mercaptoethanol and NADP+ for the maximum activity, and was not affected by pyruvate and oxalacetate. In the reaction, the enzyme consumed 2-oxoglutarate, evolved CO2 and formed succinate semialdehyde in stoichiometric relationship. The maximum enzyme activity was found at pH 7.0 and 40° C, and Km values for 2-oxoglutarate and thiamin pyrophosphate were 0.33 and 0.056 mM, respectively. These results indicate that the thiamin pyrophosphate-dependent Euglena decarboxylase belongs to a new type of decarboxylase to be designated as 2-oxoglutarate decarboxylase. The probable role of the new decarboxylase in Euglena mitochondria is discussed with regard to the tricarboxylic acid cycle

Heme oxygenase-1 induction in the brain during lipopolysaccharide-induced acute inflammation

Delirium occurs in 23% of sepsis patients, in which pro-inflammatory cytokines and nitric oxide are suggested to be involved. However, in animal experiments, even a subseptic dose of lipopolysaccharide (LPS) injection induces both pro-inflammatory cytokines and inducible nitric oxide synthase in the brain, suggesting that the brain oxidative reaction can be induced in the subseptic condition. Then, we evaluated the changes of heme oxygenase-1 (HO-1), a sensitive oxidative marker, as well as interleukin (IL)-1β, IL-6, and inductible nitric oxide synthase (iNOS) mRNA in the hypothalamus and hippocampus of rats using real-time PCR after peripheral injection of LPS (2.0 mg/kg). As a result, these four kinds of mRNAs were induced significantly in both areas after LPS injection. These results suggest that peripheral inflammation induces an oxidative reaction in the brain, even if the inflammation is not lethal. It is also considered that several pathways are involved in brain HO-1 induction

Supernova Nucleosynthesis and Extremely Metal-Poor Stars

We investigate hydrodynamical and nucleosynthetic properties of the jet-induced explosion of a population III $40M_\odot$ star and compare the abundance patterns of the yields with those of the metal-poor stars. We conclude that (1) the ejection of Fe-peak products and the fallback of unprocessed materials can account for the abundance patterns of the extremely metal-poor (EMP) stars and that (2) the jet-induced explosion with different energy deposition rates can explain the diversity of the abundance patterns of the metal-poor stars. Furthermore, the abundance distribution after the explosion and the angular dependence of the yield are shown for the models with high and low energy deposition rates $\dot{E}_{\rm dep}=120\times10^{51} {\rm ergs s^{-1}}$ and $1.5\times10^{51} {\rm ergs s^{-1}}$. We also find that the peculiar abundance pattern of a Si-deficient metal-poor star HE 1424--0241 can be reproduced by the angle-delimited yield for $\theta=30^\circ-35^\circ$ of the model with $\dot{E}_{\rm dep}=120\times10^{51} {\rm ergs s^{-1}}$.Comment: 6 pages, 3 figures. To appear in "ORIGIN OF MATTER AND EVOLUTION OF GALAXIES: From the Dawn of Universe to the Formation of Solar System", AIP Conf. Proc. 1016 (December 2007, Sapporo), eds. T. Suda, T. Nozawa, et al. (Melville: AIP

Behavioral Alterations in Response to Fear-Provoking Stimuli and Tranylcypromine Induced by Perinatal Exposure to Bisphenol A and Nonylphenol in Male Rats

The purpose of this study was to examine whether perinatal exposure to two major environmental endocrine-disrupting chemicals, bisphenol A (BPA; 0.1 mg/kg/day orally) and nonylphenol [NP; 0.1 mg/kg/day (low dose) and 10 mg/kg/day (high dose) orally] daily from gestational day 3 to postnatal day 20 (transplacental and lactational exposures) would lead to behavioral alterations in the male offspring of F344 rats. Neither BPA nor NP exposure affected behavioral characteristics in an open-field test (8 weeks of age), in a measurement of spontaneous motor activity (12 weeks of age), or in an elevated plus-maze test (14 weeks of age). A passive avoidance test (13 weeks of age) showed that both BPA- and NP-treated offspring tended to delay entry into a dark compartment. An active avoidance test at 15 weeks of age revealed that BPA-treated offspring showed significantly fewer avoidance responses and low-dose NP-treated offspring exhibited slightly fewer avoidance responses. Furthermore, BPA-treated offspring significantly increased the number of failures to avoid electrical unconditioned stimuli within 5-sec electrical shock presentation compared with the control offspring. In a monoamine-disruption test using 5 mg/kg (intraperitoneal) tranylcypromine (Tcy), a monoamine oxidase inhibitor, both BPA-treated and low-dose NP-treated offspring at 22–24 weeks of age failed to show a significant increment in locomotion in response to Tcy, whereas control and high-dose NP-treated offspring significantly increased locomotion behavior after Tcy injection. In addition, when only saline was injected during a monoamine-disruption test, low-dose NP-treated offspring showed frequent rearing compared with the control offspring. The present results indicate that perinatal low-dose BPA or NP exposure irreversibly influenced the reception of fear-provoking stimuli (e.g., electrical shock), as well as monoaminergic neural pathways

Capsaicin May Improve Swallowing Impairment in Patients with Amyotrophic Lateral Sclerosis: A Randomized Controlled Trial

Patients with neurodegenerative diseases are at an increased risk of dysphagia and aspiration pneumonia. In this study, we examined whether ingestion of capsaicin prior to swallowing changes the temporal dynamics of swallowing in such patients. In a crossover, randomized controlled trial, 29 patients with neurodegenerative diseases were given a soluble wafer containing 1.5 μg capsaicin or an identical placebo 20 min prior to testing. For evaluation with video fluoroscopy (VF), patients consumed a barium-containing liquid plus thickening material. The durations of the latency, elevating and recovery periods of the hyoid were assessed from VF. Overall, no significant differences were observed in the duration of each period between capsaicin and placebo treatments. However, reductions in the latency and elevating periods were positively correlated with baseline durations. In subgroup analyses, that correlation was observed in patents with amyotrophic lateral sclerosis (ALS) but not in patients with Parkinson’s disease. The consumption of wafer paper containing capsaicin before the intake of food may be effective in patients with dysphagia related with certain neurodegenerative diseases, particularly ALS patients. Further studies will be needed to validate this finding

Multi-drug therapy for epilepsy influenced bispectral index after a bolus propofol administration without affecting propofol's pharmacokinetics: a prospective cohort study

Some previous studies have indicated that valproate (VPA) might change the pharmacokinetics and enhance the effects of propofol. We evaluated whether clinical VPA therapy affected the propofol blood level, the protein-unbound free propofol level, and/or the anesthetic effects of propofol in the clinical setting. The subjects were divided into the control group (not medicated with antiepileptics), the mono-VPA group (medicated with VPA alone), and the poly-VPA group (medicated with VPA, other antiepileptics, and/or psychoactive drugs). General anesthesia was induced via the administration of a single bolus of propofol and a remifentanil infusion, and when the bispectral index (BIS) exceeded 60 sevoflurane was started. There were no significant differences in the total blood propofol level at 5, 10, 15, and 20 min or the protein-unbound free propofol level at 5 min after the intravenous administration of propofol between the 3 groups. However, the minimum BIS was significantly lower and the time until the BIS exceeded 60 was significantly longer in the poly-VPA group. In the multivariate regression analysis, belonging to the poly-VPA group was found to be independently associated with the minimum BIS value and the time until the BIS exceeded 60. Clinical VPA therapy did not influence the pharmacokinetics of propofol. However, multi-drug therapy involving VPA might enhance the anesthetic effects of propofol