Development of High-current Pulsed Heavy-ion-beam Technology for Applications to Materials Processing

Hiroaki Ito,Yasushi Ochiai,Katsumi Masugata 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

Development of intense pulsed heavy ion beam technology for the application of materials processing is described. We have developed a magnetically insulated ion diode for the generation of intense pulsed metallic ion beams in which the vacuum arc plasma gun is used as the ion source. When the ion diode was successfully operated at a diode voltage of 220 kV and a diode current of 10 kA, the ion beam with an ion current density of > 200 A/cm^2 and a pulse duration of 40 ns was obtained The ion composition was evaluated by a Thomson parabola spectrometer and the ion beam consists of aluminum ions (Al^((1-3)+)) of energy 140-740 keV and protons of energy 160-190 keV, and the purity was estimated to be 89 %, which is much higher than that of the pulsed ion beam produced in the conventional ion diode.The development of the bipolar pulse accelerator (BPA) was reported in order to improve the purity of intense pulsed ion beams. A double coaxial type bipolar pulse generator was developed as the power supply of the BPA. By applying the bipolar pulse with a voltage of ±90 kV and a pulse duration of about 65 ns to the drift tube of the BPA, the ion beam with an ion current density of 2 A/cm^2 and a pulse duration of 30 ns was observed at 25 mm downstream from the cathode surface, which suggests the bipolar pulse acceleration.

Association between Postoperative Neck Pain and Intraoperative Transcranial Motor-Evoked Potential Waveforms of the Trapezius Muscles in Patients with Cervical Myelopathy Who Underwent Cervical Laminoplasty

Ito Sadayuki,Sakai Yoshihito,Ando Kei,Nakashima Hiroaki,Machino Masaaki,Segi Naoki,Tomita Hiroyuki,Koshimizu Hiroyuki,Hida Tetsuro,Ito Kenyu,Harada Atsushi,Imagama Shiro 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.2

Study Design: Retrospective study.Purpose: Cervical laminoplasty is safe and effective for treating cervical myelopathy but has a higher frequency of postoperative axial pain compared to other methods. Several studies have reported on the causes of postoperative axial pain, but none have fully elucidated them. This study aimed to investigate the association between postoperative neck pain and intraoperative transcranial motor-evoked potential (MEP) waveforms of the trapezius muscles using transcranial MEPs.Overview of Literature: Few studies have investigated the association between postoperative neck pain and intraoperative transcranial MEP waveforms of the trapezius muscles in patients with cervical laminoplasty.Methods: A total of 79 patients with cervical myelopathy who underwent cervical laminoplasty at our facility between June 2010 and March 2013 were included in this study. Intraoperative control and final waveform were evaluated based on the trapezius muscle MEPs by measuring the latency and amplitude. A neck pain group comprised patients with higher neck pain Visual Analog Scale scores from preoperative value to 1 year postoperatively. The cross-sectional areas of the trapezius muscles and the MEP latencies and amplitudes were compared between patients with and without neck pain.Results: The latency and amplitude of the control waveforms were not significantly different between groups. The neck pain group had a significantly shorter final waveform latency (neck pain: 23.6±2.5, no neck pain: 25.8±4.5; p =0.019) and significantly larger amplitude (neck pain: 2,125±1,077, no neck pain: 1,630±966; p =0.041) than the no neck pain group.Conclusions: Postoperative neck pain was associated with the final waveform latency and amplitude of the trapezius muscle MEPs during cervical laminoplasty. Intraoperative electrophysiological trapezius muscle abnormalities could cause postoperative neck pain.

Emission Characteristics of a High-energy Pulsed-ion-beam Produced in a Dense Plasma Focus Device

Hiroaki Ito,Yuuki Nishino,Katsumi Masugata 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

The characteristics of ion beams produced in a Mather-type plasma focus device have been studied. When a capacitor bank of 41.6 μF was charged to 30 kV, the discharge current reached a peak current of 450 kA, and after the current dip, an ion current density of 8 kA/cm^2 with a pulse width of 60 ns was obtained 110 mm downstream from the top of the anode on the axis. In order to evaluate the angular distribution of the ion current density and the ion energy spectrum, we arrayed the biased ion collectors and the incident angle resolved energy spectrometers simultaneously at nine di®erent angular positions (-80˚, -60˚, -40˚, -20˚, 0˚, 30˚, 50˚, 70˚, and 90˚) on a circumference of 110 mm in radius, centered at the focus. From measurements with the BIC, we found that the angular distribution of the ion current density was axially symmetric and that the ion current density decreased with increasing emission angle. Experimental results for the energy spectrum showed that the proton beam energy was distributed from 0.1 MeV to 1.4 MeV and that ions with energies lower than 300 keV were distributed widely over emission angles ranging from -80˚ to 90˚, with higher-energy ions (>1 MeV) being con¯ned to emission angles of -20˚ ∼ 30˚. In addition, the ion energy and the track density were found to decrease rapidly with increasing emission angle.

Preservative Techniques for Exchanging Internal Moisture to Make a Processed Flower Having Natural Pigments

Hiroaki Ito,Takahiro Hayashi,Masaki Hashimoto,Katsuro Miyagawa,Saori Nakamura,Susumu Yazawa 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Evaluation of the Association between Neck Pain and the Trapezius Muscles in Patients with Cervical Myelopathy Using Motor Evoked Potential: A Retrospective Study

Ito Sadayuki,Sakai Yoshihito,Harada Atsushi,Ando Kei,Kobayashi Kazuyoshi,Nakashima Hiroaki,Machino Masaaki,Kambara Shunsuke,Inoue Taro,Hida Tetsuro,Ito Kenyu,Ishiguro Naoki,Imagama Shiro 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.5

Study Design: Retrospective study. Purpose: We aimed to use motor evoked potentials (MEPs) to examine the association of electrophysiological assessment of the trapezius muscle with neck pain. Overview of Literature: Previous reports on the association of neck pain with the trapezius muscle have focused on surface electromyograms and muscle oxygenation; however, to our knowledge, none of these studies included detailed data on MEPs. Methods: The study included 100 patients with cervical myelopathy who underwent surgery at the National Center for Geriatrics and Gerontology in Obu, Japan from June 2010 to March 2013. Before the surgery, neck pain was evaluated using a Visual Analog Scale (a score ≥50 indicated neck pain and a score <50 indicated no neck pain). The preoperative cross-sectional areas of the trapezius muscles were measured with cervical magnetic resonance imaging sagittal T2-weighted images. Cranial stimulation under general anesthesia was used to derive the MEPs, enabling the measurement of latency and amplitude, using preoperative MEPs of the trapezius muscles. Results: The MEP of the trapezius muscle in patients with neck pain had significantly shorter latencies than those in patients who did not have neck pain. However, there was no significant difference in the amplitude between patients with and without neck pain. However, this tended to be greater in patients with neck pain as compared to that in those without neck pain. The cross-sectional area of the trapezius muscle in patients with neck pain was significantly smaller than that in those who did not have neck pain. Conclusions: MEPs revealed electrophysiological abnormalities of the trapezius muscles in patients with neck pain, supporting a relationship of neck pain with the trapezius muscles.

The Prevalence and Risk Factors for S2 Alar-Iliac Screw Loosening with a Minimum 2-Year Follow-up

Hiroaki Nakashima,Tokumi Kanemura,Kotaro Satake,Kenyu Ito,Yoshimoto Ishikawa,Jun Ouchida,Naoki Segi,Hidetoshi Yamaguchi,Shiro Imagama 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.2

Study Design: A retrospective cohort study. Purpose: The purpose of this study was to investigate the prevalence and risk factors for S2 alar-iliac (SAI) screw loosening following lumbosacral fixation, with a minimum 2-year follow-up. Overview of Literature: Although SAI screws allow surgeons to perform lumbosacral fixation with a low profile and enhanced biomechanical strength, screw loosening following surgery can occur in some cases. However, few studies have investigated the prevalence and risk factors for SAI screw loosening. Methods: This retrospective study included 35 patients (mean age, 72.8±8.0 years; male, 10; female, 25) who underwent lumbosacral fixation using SAI screws with at least 2 years of follow-up. SAI screw loosening and L5–S bony fusion were assessed using computed tomography. The period for which the screws appeared loose and the risk factors for SAI screw loosening were investigated 2 years after surgery. Results: A total of 70 SAI screws and 70 S1 pedicle screws were inserted. Loosening was observed 0.5, 1, and 2 years after surgery in 17 (24.3%), 35 (50.0%), and 35 (50.0%) SAI screws, respectively. Bony fusion rate at L5–S was significantly lower in patients with SAI screw loosening than in those without screw loosening (65.0% vs. 93.3%, p=0.048). The score for SAI screw contact with the iliac cortical bone and the bony fusion rate at L5–S were significantly lower in the loosening group than in the non-loosening group (1.8±0.5 vs. 2.2±0.3, p<0.001, respectively). Postoperative pelvic incidence–lumbar lordosis was significantly higher in the loosening group than in the non-loosening group (7.9°±15.4° vs. 0.5°±8.7°, p=0.02, respectively). Conclusions: SAI screw loosening is closely correlated with pseudoarthrosis at L5–S. Appropriate screw insertion and optimal lumbar lordosis restoration are important to prevent postoperative complications related to SAI screws.

N=4 instanton calculus in <i>Ω</i> and R–R backgrounds

Ito, Katsushi,Nakajima, Hiroaki,Saka, Takuya,Sasaki, Shin Elsevier 2012 Nuclear physics, B Vol.860 No.2

<P><B>Abstract</B></P><P>We study the instanton calculus for N=4 super Yang–Mills theory in ten-dimensional <I>Ω</I>-background with the R-symmetry Wilson line gauge field. From the ADHM construction of instantons in the background, we obtain the deformed instanton effective action. For a certain case we get the effective action of N=<SUP>2⁎</SUP> theory in the <I>Ω</I>-background. We also study the low-energy effective D(−1)-brane action for the D3/D(−1)-brane system in the R–R 3-form field strength backgrounds and find that the action agrees with the instanton effective action in the <I>Ω</I>-background.</P>

Advantage of urological experience with both transperitoneal and retroperitoneal laparoscopy in lymph node biopsy for malignant lymphoma diagnosis

Hiroaki Kawanishi,Katsuhiro Ito,Satoshi Kamido,Yuka Kohno,Toshihiro Uemura,Keiji Kato,Hirotsugu Uetsuki,Hitoshi Ohno,Kazuhiro Okumura 대한비뇨의학회 2016 Investigative and Clinical Urology Vol.57 No.6

Purpose: Laparoscopic urologists are familiar with both transperitoneal and retroperitoneal approaches. That experience is an advantage when devising a strategy for intra-abdominal lymph node biopsy. We report the feasibility and effectiveness of laparoscopic biopsy using a urological laparoscopic technique for the treatment of patients with clinically suspected intra-abdominal lymphoma. Materials and Methods: From October 2010 to April 2015, a total of 22 patients underwent laparoscopic biopsy for suspected intra-abdominal lymphoma. We adopted a retroperitoneal approach for paraaortic or paracaval masses, whereas we used a transperitoneal approach for mesenteric, iliac, or obturator masses. Whenever possible, an entire node was removed; otherwise, the biopsy consisted of wedge resection sized at least 1 cm3. Results: Biopsy specimens were obtained from the following lymph node sites: 10 paraaortic, 5 paracaval, 3 mesenteric, 2 obturator, 1 common iliac, and 1 perinephric fat. Laparoscopic lymph node biopsy was completed in all patients, and there were no conversions to open surgery. The median operating time was 97 minutes (range, 62–167 minutes). The estimated blood loss was <50 mL in all cases. Postoperatively, one patient (4.5%) had symptomatic chylous lymphocele that required surgical intervention. Precise diagnosis was established for all patients: malignant lymphoma in 20 patients and metastatic urothelial carcinoma and squamous cell carcinoma of unknown origin in 1 patient each. All lymphomas could be fully subclassified. Conclusions: Appropriate use of the transperitoneal or retroperitoneal approach is safe and effective for laparoscopic lymph node biopsy in patients with suspected intra-abdominal lymphoma.

Fabrication of Ruby thin film for temperature indicator application

Hiroaki Aizawa,Kenichi Ito,Sayaka Takahashi,Shuji Komuro,Yukari Miyazaki,Tooru Katsumata 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

Chromium doped sapphire (Ruby) films have been fabricated on Si substrate by laser ablation, and their fundamental optical property and thermal characteristics are evaluated for temperature sensor application. The red emission near 700 nm which originates from 3d transition in Cr<SUP>3+</SUP> ions was clearly observed from the Ruby films. The split of PL peak, originated in 3d-orbital of chromium ion, is also clearly observed from Ruby films. Temperature dependence of PL spectrum from ruby films was measured under Ar laser excitation. PL intensity and PL peak positiongreatly vary with temperature ranging from 293 K to 443 K. To take the advantage of this phenomenon, the temperature sensor with calibration free can be developed.

Posing Questions during Experimental Operations for Safety Training in University Chemistry Experiments

Kaori Ito,Hiroaki Taguchi,Kaori Fujinami 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.3