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Search Results: 1 - 10 of 4821 matches for " Hiroshi Okawa "
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Magnetic analyses of isosceles tricobalt(II) complexes containing two types of octahedral high-spin cobalt(II) ions  [PDF]
Hiroshi Sakiyama, Harry Adams, David E. Fenton, Laura R. Cummings, Paul E. McHugh, Hisashi Okawa
Open Journal of Inorganic Chemistry (OJIC) , 2011, DOI: 10.4236/ojic.2011.13005
Abstract: The observed magnetic data for two isosceles tricobalt(II) complexes have been successfully analyzed, considering the axial distortion around each cobalt(II) ion, the local spin-orbit coupling, the anisotropic exchange interactions, and the intermolecular exchange interactions. The complexes each contains two types of octahedral high-spin cobalt(II) ions (CoA and CoB) in the shape of an isosceles triangle (CoA1–CoB–CoA2), and the contribution of the orbital angular momentum is significant. The exchange interaction between the CoA and CoB ions is practically negligible (J = ~ 0), whereas the interaction between the CoA1 and CoA2 ions is ferromagnetic (J’ > 0) for both complexes.
Plasma-Electrolysis of Dinitrophenol in Gas-Liquid Boundary and Interpretation Using Molecular Orbital Theory  [PDF]
Hiroshi Okawa, Hiroki Kuroda, Keiko Hirayama-Katayama, Shin-Ichiro Kojima, Tetsuya Akitsu
World Journal of Engineering and Technology (WJET) , 2019, DOI: 10.4236/wjet.2019.71010
The advanced oxidation of 2,4-dinitrophenol (DNP), 2,5-DNP, and 3,4-DNP in aqueous solution has been investigated using a multi-gas, dielectric barrier discharge. Dielectric barrier discharge was operated in the aqueous solution and gas boundary. The degradation was measured by high performance liquid chromatography (HPLC). The acceleration of the advanced-oxidation has been investigated by the combination of the anion exchange polymer membrane. The result indicated that the degradation pathways involve a rapid detachment of the nitro group and a slow opening of the aromatic-ring. The hydroxyl radical and the excited hydroxyl anion are responsible for the primary attack of the DNP with the production of dihydroxy-nitrobenzenes. The attack of hydroxyl radical occurs at the benzene ring carbon activated by the presence of a phenolic OH group and a nitro group. The result suggested that the reaction is dominated by a pseudo-first order kinetic reaction. The degradation process is interpreted using Molecular Orbital Theory.
Intraoperative Open-Cavity Implant for Accelerated Partial Breast Irradiation Using High-Dose Rate Multicatheter Brachytherapy in Japanese Breast Cancer Patients: A Single-Institution Registry Study  [PDF]
Kazuhiko Sato, Yoshio Mizuno, Masahiro Kato, Takahiro Shimo, Jun Kubota, Naoko Takeda, Yuko Inoue, Hiroshi Seto, Tomohiko Okawa
Journal of Cancer Therapy (JCT) , 2012, DOI: 10.4236/jct.2012.325104
Abstract: Background: Previous research has compared the efficacies of accelerated partial breast irradiation (APBI) and wholebreast irradiation (WBI). APBI immediately after surgery may provide more benefit after intraoperative insertion of catheters. Although balloon catheter-based APBI is available in the US, it is difficult in Japanese women, who have relatively small breasts. With the applicators being implanted during tumor removal, APBI can be started immediately after surgery. The aim of this study was to assess the safety and efficacy of APBI using the intraoperative open-cavity implant technique. Method: Patients (age≥40 years) with invasive breast cancer (diameter≤3 cm) were enrolled. Before lumpectomy, the insertion of applicators and delivery doses were simulated by computed tomography (CT). After confirmation of free margins and negative sentinel nodes (SNs) using frozen section analysis, applicators were inserted. Postoperative CT-based dose distribution analysis was performed using dose-volume histograms. APBI was started on the day of surgery, delivering 32 Gy in 8 fractions over the following 5-6 days, and it covered a distance of 2 cm from tumor margins. This observational study was approved by the institutional review board of our hospital. Results: From October 2008 to July 2012, 157 women (160 lesions) were enrolled (age 55.0 years, <40:9, SN+: 25, for patients’ request). The mean number of applicators used was 6.4 (2-15) and mean planning target volume was 35.8 cm3 (6.5-137.1 cm3). All radiotherapy-related toxicities were mild. However, 12 patients (7.5%) experienced wound breakdown because of surgical site infection. Two patients developed ipsilateral breast tumor recurrence (1 marginal, 1 at a distant site). Conclusions: Despite the small number of participants and a short follow-up period, our results suggest that this technique could be helpful in establishing clinical safety and efficacy.
Sentinel-Node-Driven Personalized Radiation Techniques Ranging from Partial Breast Irradiation to Regional Nodal Radiation after Breast-Conserving Surgery  [PDF]
Kazuhiko Sato, Yoshio Mizuno, Hiromi Fuchikami, Masahiro Kato, Takahiro Shimo, Jun Kubota, Naoko Takeda, Yuko Inoue, Hiroshi Seto, Tomohiko Okawa
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.47A008

Background: Breast-conserving surgery (BCS) followed by whole breast irradiation (WBI) has become the standard of care for treating patients with early-stage breast cancer. Recently, various radiation techniques followed by BCS have been reported. We have been investigating “personalized radiotherapy after BCS” ranging from accelerated partial breast irradiation (APBI) to WBI with regional nodal irradiation (RNI) based on the axillary node status. In this study, we compared different cohorts that received personalized radiotherapy. Method: Of 317 consecutive patients who underwent BCS followed by radiotherapy since November 2007, 187 who received APBI and 122 who received WBI were analyzed. Results: The local-only recurrence rate was 1.1% in the APBI group and 3.3% in the WBI group, and the regional-only recurrence rate was 1.1% for APBI and 0.8% for WBI. Conclusions: The clinical efficacy of APBI for local control after BCS was comparable to that of WBI ± RNI. Although this study was based on a small number of patients with a short follow-up period, the feasibility of breast-conserving therapy using multicatheter brachytherapy to achieve acceptable clinical outcomes was demonstrated.

The fate of Eichhornia azurea (Sw.) Kunth. detritus within a tropical reservoir
Santino, Marcela Bianchessi da Cunha;Bianchini Jr., Irineu;Okawa, Marco Hiroshi;
Acta Limnologica Brasiliensia , 2010, DOI: 10.4322/actalb.02202001
Abstract: aim: this study is aimed at comparing the kinetics of decomposition of eichhornia azurea and discussing the fate of its detritus; methods: the samples of aquatic macrophytes and water were collected in the piraju reservoir (s?o paulo state, brazil). the plant material was oven-dried and triturated and for each experimental condition (aerobic and anaerobic), 72 mineralization chambers were prepared with plant fragments and reservoir water. on sampling days the particulate and dissolved organic matter were quantified (on carbon basis poc and doc, respectively); results: the decomposition of e. azurea is more efficient under aerobic conditions, being 2.2 times faster than for the anaerobic process, according to the amount of mineralized carbon. for the decay of leaves, stems and roots of e. azurea the aerobic processes were 1.22-fold faster. it is assumed that the fractions responsible for the high oxygen consumption have reduced periods of half-time, and therefore do not accumulate in the ecosystems. owing to the biomass of e. azurea in the piraju reservoir, the aerobic decay of e. azurea can promote moderate depletion in the dissolved oxygen budget. with the rate of the mineralization of refractory materials (ξ half-time varying from 385 to 462 days), the fibrous debris of this plant, i.e. refractory fractions, associated with the appropriate conditions of ph and oxi-reduction potential, can contribute to the gas production and storage of particulate organic matter in sediments.
A Surgical Treatment for Adult Muscular Torticollis
Song Ho Chang,Seiji Ohtori,Akihiko Okawa,Koui Kawamura,Hiroshi Saiki,Izumi Nakada,Takashi Shimada,Junichi Nakamura,Kazuhisa Takahashi,Hiroshi Sugiyama
Case Reports in Orthopedics , 2013, DOI: 10.1155/2013/965693
Abstract: Adult presentation of neglected congenital muscular torticollis (CMT) is rare. Therefore, efficacy of surgical treatment for adult CMT is unclear. We experienced a case of neglected CMT in a 28-year-old male patient and report the surgical result here. We conducted unipolar resection at the distal end of the sternocleidomastoid muscle (SCM). After surgery, the range of neck movement and head tilt improved, and his appearance was cosmetically improved despite the long-standing nature of the deformity. We concluded that surgical management of adult patients with neglected congenital muscular torticollis may be a treatment option. 1. Introduction Congenital muscular torticollis (CMT) is the third most common congenital musculoskeletal anomaly after dislocation of the hip and clubfoot [1]. The term congenital muscular torticollis (CMT) refers to a neck deformity that primarily involves shortening of the sternocleidomastoid muscle that leads the head to turn toward the affected side and the chin to point to the opposite side [2]. When diagnosed early, it is obvious that it can be managed with good or excellent results [2]. Ling et al. have stated that the optimal time for surgery is between 1 and 4 years [3, 4]. This is based on the finding that most children treated before the age of 1 year respond well to conservative treatment [3, 4]. However, there are few reports that indicate the efficacy of surgery for neglected cases in adults [5, 6]. In the current report, we experienced a case of neglected muscular torticollis in a 28-year-old patient. We report the efficacy of unipolar tenotomy of the sternocleidomastoid muscle (SCM) for this adult patient. 2. Case Presentation This report was approved by the patient after informed consent. A 28-year-old male patient had a diagnosis of CMT at birth. However, his treatment was neglected until he began to care about his cosmetic appearance. He came to our clinic when he was 28 years of age, and he hoped for surgical treatment to improve his cosmetic problem. He had no clinical past history and no family history. He showed slight facial asymmetry. He had a 7° right side rotational deficit and 35° lateral flexion deficit before surgery. We could palpate a hard mass in the SCM in his left neck. We planned resection of the SCM for the patient. At first, unipolar resection at the distal end of SCM was performed. Rotation and lateral flexion at the left side improved, and tension of the SCM disappeared during surgery; we did not add resection at the proximal end of the SCM. There was no significant complication after
New Developments in Lattice QCD: Calculation of Flavor Singlet Nucleon Matrix Elements and Hadron Scattering Lengths
Masanori Okawa
Physics , 1995, DOI: 10.1016/0920-5632(96)00041-2
Abstract: Recent developments in lattice QCD calculation of flavor singlet nucleon matrix elements are reviewed. Substantial sea quark contributions are found in the $\pi$-$N\ \sigma$ term and the quark spin content of the nucleon such that the total magnitude including valence contributions is in reasonable agreement with experiments. Some problems with flavor non-singlet nucleon matrix elements are pointed out. Recent work on lattice QCD calculation of hadron scattering length is also discussed.
Derivative corrections to Dirac-Born-Infeld Lagrangian and non-commutative gauge theory
Yuji Okawa
Physics , 1999, DOI: 10.1016/S0550-3213(99)00691-4
Abstract: We consider the constraints on the effective Lagrangian of the rank-one gauge field on D-branes imposed by the equivalence between the description by ordinary gauge theory and that by non-commutative gauge theory in the presence of a constant B field. It is shown that we can consistently construct the two-derivative corrections to the Dirac-Born-Infeld Lagrangian up to the quartic order of field strength and the most general form which satisfies the constraints up to this order is derived.
Open string states and D-brane tension from vacuum string field theory
Yuji Okawa
Physics , 2002, DOI: 10.1088/1126-6708/2002/07/003
Abstract: We propose a description of open string fields on a D25-brane in vacuum string field theory. We show that the tachyon mass is correctly reproduced from our proposal and further argue that the mass spectrum of all other open string states is correctly obtained as well. We identify the string coupling constant from the three-tachyon coupling and show that the tension of a D25-brane is correctly expressed in terms of the coupling constant, which resolves the controversy in the literature. We also discuss a reformulation of our description which is rather similar to boundary string field theory.
Higher-derivative terms in one-loop effective action for general trajectories of D-particles in Matrix theory
Yuji Okawa
Physics , 1999, DOI: 10.1016/S0550-3213(99)00266-7
Abstract: The one-loop effective action for general trajectories of D-particles in Matrix theory is calculated in the expansion with respect to the number of derivatives up to six, which gives the equation of motion consistently. The result shows that the terms with six derivatives vanish for straight-line trajectories, however, they do not vanish in general. This provides a concrete example that non-renormalization of twelve-fermion terms does not necessarily imply that of six-derivative terms.
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