Yuichi Kitagawa

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Synaptic plasticity, neuronal activity-dependent sustained alteration of the efficacy of synaptic transmission, underlies learning and memory. Activation of positive-feedback signaling pathways by an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) has been implicated in synaptic plasticity. However, the mechanism that determines the [Ca(2+)](i)(More)
Although internal organ injury in car crashes occurs at a relatively lower frequency compared to bone fracture, it tends to be ranked higher in terms of injury severity. A generalized injury risk can be assessed in car crash tests by evaluating abdominal force and viscous criterion (VC) using a crash test dummy, but the injury risk to each organ cannot be(More)
Thoracic deformation under an applied load is an established indicator of injury risk, but the force required to achieve an injurious level of deformation currently is not understood adequately. This article evaluates how two potentially important factors, loading condition and muscle tensing, affect the structural response of the dynamically loaded thorax.(More)
BACKGROUND The incidences of surgery-field disorders such as femur neck fracture and colorectal cancer in elderly persons have increased with the rapid aging of society. In such patients, postoperative delirium is also frequent. Patients should be generally assessed from the aspect of both physical and mental conditions in order to predict a high-delirium(More)
Nucleic acids are useful for biomedical targeting and sensing applications in which the molecular environment is different from that of a dilute aqueous solution. In this study, the influence of various types of mixed solutions of water and water-soluble organic compounds on RNA was investigated by measuring the catalytic activity of the hammerhead ribozyme(More)
Cellular ribozymes exhibit catalytic activity in media containing large numbers of anionic compounds and macromolecules. In this study, the RNA cleavage activity of the hammerhead ribozyme induced by Mg2+ was investigated using the solutions containing background nucleic acids, small phosphate and carboxylic acid compounds, and neutral polymers. Analysis of(More)
OBJECTIVES The objective of this study is to examine the effectiveness of the active head restraint system in reducing neck injury risk of car occupants in low-speed rear impacts. METHODS A human body FE model "THUMS" was used to simulate head and neck kinematics of the occupant and to evaluate loading to the neck. Joint capsule strain was calculated to(More)
Posterior translation of the tibia with respect to the femur can stretch the posterior cruciate ligament (PCL). Fifteen millimeters of relative displacement between the femur and tibia is known as the Injury Assessment Reference Value (IARV) for the PCL injury. Since the anterior protuberance of the tibial plateau can be the first site of contact when the(More)
Lanthanide (Ln(III)) complexes form an important class of highly efficient luminescent materials showing characteristic line emission after efficient light absorption by the surrounding ligands. The efficiency is however lowered by back energy transfer from Ln(III) ion to the ligands, especially at higher temperatures. Here we report a new strategy to(More)
Novel organo-Eu(III) luminophores, Eu(hfa)x(CPO)y and Eu(hfa)x(TCPO)y (hfa: hexafluoroacetylacetonate, CPO: 4-carboxyphenyl diphenyl phosphine oxide, TCPO: 4,4',4″-tricarboxyphenyl phosphine oxide), were synthesized by the complexation of Eu(III) ions with hfa moieties and CPO or TCPO ligands. The thermal and luminescent stabilities of the luminophores are(More)