Sound generation by unsteady flow ejecting from the vibrating glottis based on a distributed parameter model of the vocal cords

金沢大学大学院自然科学研究科The purpose of the present paper is to clarify the effects of unsteady glottal flow on phonation. We perform numerical experiments with respect to vocal cord vibrations in order to verify the validity of the proposed model for a glottal sound source. In addition, the prediction of pressure waves induced by unsteady glottal jets is attempted. Good agreement between the numerical results and the measured data of the properties of the glottal source indicates that the proposed model is a good tool for the analysis of speech production. Simulated pulsatile glottal jets show the generation of high-frequency noises in a pressure wave at the glottis and the unsteady and asymmetric motion of vortices. These vortices cause amplitude fluctuations in the pressure wave downstream near the glottis, although pressure waves far from the glottis are not greatly affected. In conclusion, the unsteady glottal flow affects only the area near the glottis and does not greatly affect speech waves radiating from the mouth. © 2007 The Acoustical Society of Japan

Effects of the false vocal folds on sound generation by an unsteady glottal jet through rigid wall model of the larynx

金沢大学大学院自然科学研究科In the present paper, the effects of the false vocal folds (FVFs) on sound generation induced by an unsteady glottal jet through a two-dimensional rigid wall model of the larynx are investigated by conducting numerical experiments. The glottal jets are simulated by solving the basic equations for a compressible viscous fluid based on the larynx model with and without the FVFs. The existence of the FVFs increases the amplitude of noise-like pressure fluctuation at the glottis and faraway from the glottis. Furthermore, the FVFs give rise to the broadbanding of the pressure spectrum throughout the fluid domain. These results indicate that the FVFs have a profound effect on the generation of broadband noise components in a speech wave. © 2007 The Acoustical Society of Japan

Polarization envelope helicity dependent photovoltage in GaAs/Al03Ga07As modulation-doped quantum well

In this study, we demonstrate the switching of the direction of the photocurrent in an n-type GaAs/Al0.3Ga0.7As modulation-doped quantum well using a polarization pulse-shaping apparatus containing a 4f setup. The right- and left-polarization-twisting pulses with a polarization rotation frequency in the THz-regime are incident on a modulation-doped quantum well. The results show that the sign of the photovoltage is dependent on the direction of rotation of the polarization-twisting pulses, which can be explained by the circular photogalvanic effect combined with the production of a classical edge photocurrent from the acceleration of free electrons in the vicinity of the sample edge by the incident optical electric field. The wide range over which the polarization-rotation frequency may be tuned makes this method a powerful tool to investigate the response of an extensive variety of materials in the THz-regime

Gastric Endocrine Cell Carcinoma Coexistent with Adenocarcinoma

A 69-year-old female presented to our institution with epigastralgia and abdominal distension. Upper gastrointestinal series revealed a 5 cm ulcerative lesion with irregular margins and elevated distinct borders from the angle to the pyloric ring. Gastroendoscopy revealed a Borrmann type 2 tumor. Several biopsied specimens revealed proliferation of small and heterogeneous cancer cells with rich chromatin and fibrous septum with rich vessels at connective tissues, which was confirmed as gastric endocrine cell carcinoma (ECC) on immunostaining with chromogranin and synaptophysin. Furthermore, other specimens revealed atypical cells forming glandular structures, which were confirmed as well-differentiated tubular adenocarcinomas. Distal gastrectomy with D2 lymph node dissection and Billroth I reconstruction was performed. Pathological examination of the gross specimen revealed that adenocarcinoma comprised <10% of all cancer cells. Close analysis of ECC revealed a mixture of small and large cells. According to the WHO 2010 classification of gastrointestinal neuroendocrine tumors, this gastric tumor was diagnosed as neuroendocrine carcinoma. The patient was administered adjuvant chemotherapy with cisplatin and etoposide. One year following surgery, follow-up abdominal CT revealed multiple liver metastases. The patient received the best supportive care but eventually died 18 months after surgery. Here we present this case of gastric ECC coexistent with adenocarcinoma

Examination of prognostic factors in patients undergoing surgery for colorectal perforation: A case controlled study

AbstractObjectiveTo determine if the POSSUM, SOFA, MPI, and SAS scores provide a better measure of severity for patients with prognostic factors undergoing surgery for colorectal perforation.SubjectsFifty-nine patients who underwent surgery between 1996 and 2012.MethodsWe retrospectively reviewed background factors, blood and physiological test results, and intraoperative findings of patients who survived and those who died. We also compared the POSSUM, SOFA, MPI, and SAS scores. Multivariate analysis was performed for factors that were significant by univariate analysis, and selected factors were used to produce a predictive prognostic model.ResultsUnivariate analysis revealed significant differences in age, anticoagulant/steroid administration, serum creatinine level, PF ratio, base excess (BE), chest radiography, pulse rate, and severity of peritoneal soiling. Age, serum creatinine level, pulse rate, and severity of peritoneal soiling were selected for multivariate analysis; only pulse rate was significantly different. There were significant differences between the two groups in POSSUM PS, OSS, SOFA, and MPI scores, and a comparison in terms of the ROC curve showed that our model had the highest peak; the area under the curve was 94.8% compared with 70–80% for the other systems, suggesting that our model is better than those systems.ConclusionsPOSSUM and SOFA are valid methods of evaluating risk from colorectal perforation, but our study revealed addition risk factors: (1) the PF ratio and BE, which are not included in POSSUM; (2) the pulse rate and severity of peritonitis, which are not included in SOFA; and (3) anticoagulant/steroid hormone administration

Evidence and mechanism of efficient thermally activated delayed fluorescence promoted by delocalized excited states

The design of organic compounds with nearly no gap between the first excited singlet (S1) and triplet (T1) states has been demonstrated to result in an efficient spin-flip transition from the T1 to S1 state, that is, reverse intersystem crossing (RISC), and facilitate light emission as thermally activated delayed fluorescence (TADF). However, many TADF molecules have shown that a relatively appreciable energy difference between the S1 and T1 states (~0.2 eV) could also result in a high RISC rate. We revealed from a comprehensive study of optical properties of TADF molecules that the formation of delocalized states is the key to efficient RISC and identified a chemical template for these materials. In addition, simple structural confinement further enhances RISC by suppressing structural relaxation in the triplet states. Our findings aid in designing advanced organic molecules with a high rate of RISC and, thus, achieving the maximum theoretical electroluminescence efficiency in organic light-emitting diodes

Fault detection system for ICRF transmission line in LHD

The transmission line is one of the most important components of ion cyclotron range of frequencies (ICRF) heating devices. In the case of unexpected trouble on the line, such as a breakdown, immediate power-off is necessary in order to avoid severe damage on the line. Breakdowns are difficult to detect with a reflection monitor, since the reflection may originate from a change in the antenna-plasma coupling. In the Large Helical Device (LHD), a Fault Detection System (FDS) for the transmission line was developed, which detects the breakdown utilizing the unbalance of three signals from the both ends of the line. For the precise balancing in the normal condition, the calibration is iteratively conducted. FDS is insensitive to the change of the antenna impedance, therefore, FDS can detect breakdown clearly. Frequency shift is also detectable with the FDS applied to a long transmission line. Therefore, the self-oscillation accompanying frequency shift could be detected in addition to breakdown

Study of ion cyclotron range of frequencies heating characteristics in deuterium plasma in the Large Helical Device

The characteristics of ion cyclotron range of frequencies (ICRF) minority ion heating with a hydrogen minority and deuterium majority plasma were studied by ICRF modulation injection experiments in the Large Helical Device (LHD). In recent experiments with deuterium plasma, no significant increase in the neutron emission rate due to ICRF second harmonic deuteron heating was observed. Therefore, in this study, the neutron emission rate was used to refer to the information regarding the thermal ion component. Like the results of the observations of the heating efficiencies at various minority proton ratios, the experimental results showed good agreement with the simple model simulation of ICRF wave absorption. During these experiments, the accelerated minority hydrogen ions were observed by neutral particle analyzers. The counting rates of the energetic particles were higher in the lines of sight passing through the helical ripple than across the magnetic axis, and the counting rate decreased as the minority hydrogen ion ratio increased. The dependence of the minority hydrogen ion ratio on the density of the energetic ions was consistent with the experimentally observed heating efficiencies and simulations. The heating efficiency of ICRF minority ion heating could be well explained by simple model simulation in the LHD deuterium experiment

Third Harmonic ICRF Heating in LHD High Beta Experiments

The ion cyclotron range of frequencies (ICRF) heating power injection in the hydrogen experiment in LHD was demonstrated after the upgrade of ICRF antennas. The ICRF wave couples and accelerates the energetic particles injected by perpendicular-NBIs with 40 keV. The simulation by the MORH code shows the existence of energetic particles around the ICRF third harmonic resonance layers. As the result of ICRF heating power deposition, the beta value increased by 0.2% in absolute beta mainly due to the increased energetic particle content. The increase of energetic ions particularly around 60 keV, which should be accelerated by the ICRF heating, is observed. The ICRF heating efficiency was approximately 30%–50%, estimated from the break-in-slope analysis at the turn off timing of ICRF power from the stored energy measured by diamagnetic loops. This increase of the stored energy is mostly the contribution of the increased energetic particles. The heating efficiency increases as the density increases