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Search Results: 1 - 10 of 139017 matches for " Kitagawa K "
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High-temperature spin relaxation process in Dy$_2$Ti$_2$O$_7$ probed by $^{47}$Ti-NQR
K. Kitagawa,R. Higashinaka,K. Ishida,Y. Maeno,M. Takigawa
Physics , 2008, DOI: 10.1103/PhysRevB.77.214403
Abstract: We have performed nuclear quadrupole resonance (NQR) experiments on $^{47}$Ti nuclei in Dy$_2$Ti$_2$O$_7$ in the temperature range 70 -- 300 K in order to investigate the dynamics of $4f$ electrons with strong Ising anisotropy. A significant change of the NQR frequency with temperature was attributed to the variation of the quadrupole moment of Dy $4f$ electrons. A quantitative account was given by the mean field analysis of the quadrupole-quadrupole (Q-Q) interaction in the presence of the crystalline-electric-field splitting. The magnitude and the temperature dependence of the nuclear spin-lattice relaxation rate was analyzed, including both the spin-spin and the Q-Q interactions. The results indicate that these two types of interaction contribute almost equally to the fluctuation of Dy magnetic moments.
S wave superconductivity in newly discovered superconductor BaTi$_2$Sb$_2$O revealed by $^{121/123}$Sb-NMR/Nuclear Quadrupole Resonance measurements
S. Kitagawa,K. Ishida,K. Nakano,T. Yajima,H. Kageyama
Physics , 2013, DOI: 10.1103/PhysRevB.87.060510
Abstract: We report the $^{121/123}$Sb-NMR/nuclear quadrupole resonance (NQR) measurements on the newly-discovered superconductor BaTi$_2$Sb$_2$O with a two-dimensional Ti$_2$O square-net layer formed with Ti$^{3+}$ (3$d^1$). NQR measurements revealed that the in-plane four-fold symmetry is broken at the Sb site below $T_{\rm A} \sim$ 40 K, without an internal field appearing at the Sb site. These exclude a spin-density wave (SDW)/ charge density wave (CDW) ordering with incommensurate correlations, but can be understood with the commensurate CDW ordering at $T_{\rm A}$. The spin-lattice relaxation rate $1/T_1$, measured at the four-fold symmetry breaking site, decreases below superconducting (SC) transition temperature $T_{\rm c}$, indicative of the microscopic coexistence of superconductivity and the CDW/SDW phase below $T_{\rm A}$. Furthermore, $1/T_1$ of $^{121}$Sb-NQR shows a coherence peak just below $T_{\rm c}$ and decreases exponentially at low temperatures. These results are in sharp contrast with those in cuprate and iron-based superconductors, and strongly suggest that its SC symmetry is classified to an ordinary s-wave state.
Evaluation of Oxidative Stress, Antioxidant Power, and Antioxidant Potential of Breastmilk of Breast-Feeding Mothers  [PDF]
Naoko Kuramoto, Mariko Kitagawa
Health (Health) , 2017, DOI: 10.4236/health.2017.98083
Abstract: Purpose: The purpose of this study was to evaluate oxidative stress, antioxidant power, and antioxidant potential of breastmilk of breast-feeding mothers from the early postpartum period to the first 3 months postpartum, and to examine the dynamics and the relationships among them. Method: For 47 pu-erperant women who gave vaginal birth without any pregnancy complications, the oxidative stress levels (d-ROMs levels) and antioxidant power (BAP levels) in the maternal plasma as well as antioxidant potential of breastmilk (BAP levels in breastmilk) were measured 3 times, i.e., in the early puerperium (4 or 5 days after giving birth), one month after giving birth, and 3 months after giving birth. Results: The d-ROMs levels in the maternal plasma were significantly high in the early puerperium (p < 0.001), and decreased gradually in the post-partum period (p < 0.001). On the other hand, BAP levels were significantly low in the early puerperium (p < 0.001), and increased to the almost normal level during one month after giving birth. BAP levels in breastmilk were significantly high in the early puerperium compared with the other periods (p < 0.001), and decreased gradually until 3 months after giving birth (p < 0.001). BAP levels in breastmilk in the early puerperium were higher compared with the maternal BAP levels, and there was a positive correlation between BAP levels in breast-milk and those in the maternal plasma (p < 0.05). Discussion: Regarding the oxidative stress and the antioxidant defense system of breast-feeding mothers, the d-ROMs level was highest and the BAP level was lowest in the early puerperium. The BAP level then showed a clear tendency to recover in the first 3 months after giving birth. Conclusion: When the maternal antioxidant potential remains at a low level after giving birth, careful consideration should be given to the mother’s health and wellbeing because there is a possibility that it might affect the antioxidant potential of breastmilk.
Negative MRI findings in a case of degenerative myelopathy in a dog : clinical communication
M. Okada,M. Kitagawa,K. Kanayama,H. Yamamura
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v80i4.222
Abstract: An 11-year-old male Rough collie was submitted with paraparesis, but did not respond to medical treatment. Clinical signs worsened and the dog displayed paralysis, inability to stand and loss of voluntary bladder control, whereupon magnetic resonance imaging (MRI) was performed. No significant abnormalities were identified from MRI, blood tests, cerebrospinal fluid tests or radiography. After MRI, the dog developed dyspnoea and died. Autopsy and subsequent histopathological examination led to a diagnosis of degenerative myelopathy.
Application of 2-octyl-cyanoacrylate for corneal perforation and glaucoma filtering bleb leak
Okabe M,Kitagawa K,Yoshida T,Koike C
Clinical Ophthalmology , 2013,
Abstract: Motonori Okabe,1 Kiyotaka Kitagawa,2 Toshiko Yoshida,1 Chika Koike,1 Takeshi Katsumoto,2 Etsuko Fujihara,2 Toshio Nikaido1 1Department of Regenerative Medicine, University of Toyama, Graduate School of Medicine and Pharmaceutical Sciences, Toyama, 2Division of Ophthalmology, Matsue Red Cross Hospital, Japanese Red Cross Society, Shimane, Japan Background: This paper reports on the efficacy of a tissue adhesive, 2-octyl-cyanoacrylate, in the treatment of corneal perforation and glaucoma filtering bleb leak. Methods: Two eyes from two patients with corneal perforation or laceration and two eyes from two patients with bleb leak were included. The patients underwent application of 2-octyl-cyanoacrylate onto the perforated or leaking site, and a hydrogel contact lens was applied as a bandage. We also evaluated the in vitro cell toxicity of 2-octyl-cyanoacrylate in HeLa cells. Results: The two cases of corneal perforation were repaired within 22 days with one application of the tissue adhesive. The two cases of bleb leak were repaired with 2–4 applications of the tissue adhesive over 134 (range 17–134) days). There were no recurrences or adverse effects during a mean follow-up period of 12.7 months. In vitro testing revealed that 2-octyl-cyanoacrylate was markedly toxic to HeLa cells. Conclusion: Four patients with corneal perforation or bleb leak were successfully managed using 2-octyl-cyanoacrylate tissue adhesive. This simple and easy surgical technique may become an alternative therapeutic option for corneal perforation or bleb leak, although several applications of this tissue adhesive may be required. Although 2-octyl-cyanoacrylate was toxic to HeLa cells, no adverse clinical effects were noted using this adhesive. Keywords: corneal perforation, bleb leak, tissue adhesive, 2-octyl-cyanoacrylate
Magnetic Excitation in Artificially Designed Oxygen Molecule Magnet
T. Masuda,S. Takamizawa,K. Hirota,M. Ohba,S. Kitagawa
Physics , 2008, DOI: 10.1143/JPSJ.77.083703
Abstract: We performed inelastic neutron scattering experiment to study magnetic excitation of O$_2$ molecules adsorbed in microporous compound. The dispersionless excitation with characteristic intensity modulation is observed at $\hbar \omega = 7.8$ meV at low temperature. The neutron cross section is explained by spin dimer model with intradimer distance of 3.1 \AA . Anomalous behaviour in the temperature dependence is discussed in the context of enhanced magnetoelasticity in the soft framework of O$_2$ molecule.
Orbital Properties of Sr3Ru2O7 and Related Ruthenates Probed by 17O-NMR
K. Kitagawa,K. Ishida,R. S. Perry,H. Murakawa,K. Yoshimura,Y. Maeno
Physics , 2006, DOI: 10.1103/PhysRevB.75.024421
Abstract: We report a site-separated $^{17}$O-NMR study of the layered perovskite ruthenate Sr$_3$Ru$_2$O$_7$, which exhibits nearly two-dimensional transport properties and itinerant metamagnetism at low temperatures. The local hole occupancies and the spin densities in the oxygen $2p$ orbitals are obtained by means of tight-binding analyses of electric field gradients and anisotropic Knight shifts. These quantities are compared with two other layered perovskite ruthenates: the two-dimensional paramagnet Sr$_2$RuO$_4$ and the three-dimensional ferromagnet SrRuO$_3$. The hole occupancies at the oxygen sites are very large, about one hole per ruthenium atom. This is due to the strong covalent character of the Ru-O bonding in this compound. The magnitude of the hole occupancy might be related to the rotation or tilt of the RuO$_6$ octahedra. The spin densities at the oxygen sites are also large, 20-40% of the bulk susceptibilities, but in contrast to the hole occupancies, the spin densities strongly depend on the dimensionality. This result suggests that the density-of-states at the oxygen sites plays an essential role for the understanding of the complex magnetism found in the layered perovskite ruthenates.
Design and Characterization of Nano-Displacement Sensor with High-Frequency Oscillators
Akio Kitagawa
Journal of Sensors , 2011, DOI: 10.1155/2011/360173
Abstract: The circuitry of a capacitive nanometer displacement sensor using the ring oscillator has been analyzed and characterized. We focus on the sensitivity of the sensor to detect the nanometer displacement or strain. The displaced target object must be conductive and the medium around the target object must be an insulator or a vacuum. The sensitivity in the range of L < 1 μm is enhanced with decreases in the size of the sensor electrode, and using a higher free-running oscillation frequency can increase sensitivity. The proposed sensor, which converts the displacement of the target object to the oscillation frequency, was fabricated with CMOS 350 nm technology, and the sensitivity was estimated at 8.16 kHz/nm. The results of our study indicated that the presented sensor has enough sensitivity to detect the nanometer displacement of the target object at a distance within 1 μm from the surface of the sensor electrode.
Electron Spin Resonance Measurement with Microinductor on Chip
Akio Kitagawa
Journal of Sensors , 2011, DOI: 10.1155/2011/813636
Abstract: The detection of radicals on a chip is demonstrated. The proposed method is based on electron spin resonance (ESR) spectroscopy and the measurement of high-frequency impedance of the microinductor fabricated on the chip. The measurement was by using a frequency sweep of approximately 100 MHz. The ESR spectra of di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) dropped on the microinductor which is fabricated with CMOS 350-nm technology were observed at room temperature. The volume of the DPPH ethanol solution was 2 μL, and the number of spins on the micro-inductor was estimated at about 1014. The sensitivity is not higher than that of the standard ESR spectrometers. However, the result indicates the feasibility of a near field radical sensor in which the microinductor as a probe head and ESR signal processing circuit are integrated.
Duplicate publication cases in the field of Kampo (Japanese herbal medicine) in Japan
Masamichi Kitagawa
Zhong Xi Yi Jie He Xue Bao , 2011,
Abstract: Objective:Duplicate publication has a negative influence on science and publishing communities. We found duplicate publication cases in the field of Kampo (traditional Japanese herbal medicine) while compiling the Evidence Reports of Kampo Treatment (EKAT) 2009 published by the Special Committee for Evidence-based Medicine (EBM), the Japan Society for Oriental Medicine (JSOM). Therefore, we checked the articles that appeared in the EKAT 2009 and analyzed how duplicate publication occurred. Methods: The EKAT 2009 contains structured abstracts of 320 randomized controlled trial studies. We checked 384 articles referred to by the structured abstracts to identify duplicate publications according to the following criteria: hypothesis and results are the same; the authors are in common; no description as to a secondary publication is offered; no cross-references to related papers. Results: Eleven articles that appeared in the EKAT 2009 were identified as duplicate publications. These articles showed four duplicate patterns: reproducing an already published article with the same sample data and results (n=3); adding new sample data with the same results (n=1); reporting part of the preliminary sample with the same results (n=1); translating an original article into another language (n=6). Conclusion:Among the 11 duplicate publications in the EKAT 2009, we discovered 4 duplicate patterns. These patterns reflect Japanese researchers’ behavior that leads to the production of duplicate publications: the authors complete a previous article and submit it to a more prestigious journal; translate an original English article for Japanese physicians without referring to the original paper. To raise the awareness of duplicate publication among researchers, the understanding of publication ethics is essential.
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