A Study on Non-steady Groundwater Flow in a Semi-confined Aquifer

This paper deals with the groundwater flow in a semi-confined aquifer causing the phenomena of consolidation and free surface lowering. Since the main effect of consolidation has taken place before noticeable lowering of the free surface, one may solve each phenomenon on its own. The real solution may be obtained by the principle of superposition. However, the solution for lowering the free surface is delayed due to the cosolidation by a certain timelapse, depending on the placecoordinates

Study of parasitic oscillation of a multi-chip SiC MOSFET circuit based on a signal flow graph model by TCAD simulation

This study presents a novel method to evaluate oscillation condition by technology computer-aided design (TCAD) simulation and is based on a signal flow graph model and a scattering parameter (S-parameter) computed using the TCAD simulation result. The parasitic oscillation of Silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs) when a short circuit occurs has been investigated with the proposed method. The oscillation conditions of a circuit were computed with this technique and compared with those computed by TCAD transient simulation. The gate resistance to suppress oscillation is similar between these methods. Moreover, the method was also applied to estimate the stability of a circuit consisting of parallelly connected SiC MOSFETs. Two oscillation modes were taken into account. We demonstrated that the circuit parameters required to suppress parasitic oscillation can be computed using a simple calculation

Parasitic oscillation analysis of trench IGBT during short-circuit type II using TCAD-based signal flow graph model

The oscillation phenomenon of trench-type insulated gate bipolar transistors during short-circuit (SC) type II was investigated experimentally and theoretically. The gate resistance required to suppress oscillations decreased with an increasing collector voltage. The oscillation conditions were calculated from the signal flow graph model using the S -parameter based on a technology computer-aided design simulation. The calculation results reproduced the locus of the collector voltage dependence of the experimentally measured gate resistance. The oscillation mechanism was investigated using the device simulation. The response of carrier density modulation at the base-drift layer boundary was found to transmit to the collector side through the electron–hole plasma region during the oscillation, indicating that the transfer characteristics of the carrier density modulation in the drift region at the specific collector voltage influence the collector voltage dependence of the SC oscillation. The influence of circuit parameters on the oscillation was also investigated. An increase in the emitter inductance suppressed the oscillations, whereas an increase in gate inductance increases oscillations

Magnetic resonance imaging findings of age-related distance esotropia in Japanese patients with high myopia

Purpose This study aimed to investigate the characteristics of the extraocular muscles and the orbital connective tissue pulleys in Japanese patients with age-related distance esotropia (ARDE) and high myopia using magnetic resonance imaging (MRI). Methods This was a retrospective case-series study. High-resolution coronal MRI scans of 12 orbits were obtained in 6 patients with ARDE and high myopia (age range: 51–69 years). We analyzed the images to determine the positions of the rectus muscle pulleys relative to the center of the globe, the integrity of the lateral rectus-superior rectus muscle (LR-SR) band, and the LR angle (the angle between the major axis of the LR and the vertical plane). Results The distance esotropia ranged from 4 to 25∆, and 3 cases exhibited vertical deviations. The mean (±standard deviation (SD)) axial length was 28.5 (± 1.6) mm. The mean positions of the medial rectus muscle pulley and LR pulley were 1.3 mm inferior and 1.4 mm inferior, respectively, to those seen in the normal control group in our previous study (P = 0.002 and P = 0.05, respectively). All 12 orbits had abnormal elongated LR-SR bands, and 8 orbits (67%) displayed ruptured LR-SR bands. The LR angle (mean±SD; 18.8° ± 8.5°) increased significantly with the inferior displacement of the LR pulley (R2 = 0.77, P = 0.0002). Conclusions Inferior displacement of the LR pulley and abnormal LR-SR bands were seen in Japanese ARDE patients with high myopia, as was found in ARDE patients without high myopia. The LR angle might be useful for judging the degree of LR pulley displacement

Rapidly Progressive Pancytopenia, Hepatomegaly, and Abnormal Lung Uptake of Colloid in Systemic Lupus Erythematosus: Possible Saturation of Reticuloendothelial System with Blood Elements

A patient with systemic lupus erythematosus developed severe abdominal pain and tender hepatomegaly associated with progressive pancytopenia and elevated serum levels of circulating immune complexes. Liver scintigram demonstrated extreme hepatomegaly with poor colloid uptake and splenomegaly with increased colloid uptake. An unusual accumulation of colloid in the lungs was also noted. Subsequent clinical and laboratory studies raised the possibility of saturation of the reticuloendothelial system in the liver by circulating immune complexes and blood cells, a condition demonstrated in experimental animals, but not hitherto well documented in the human immune complex disorder

Clinical Parameters Reflecting Globe/orbit Volume Imbalances in Japanese Acquired Esotropia Patients with High Myopia but without Abduction Limitations

In high myopia, eye dislocation due to increased globe volume or tight orbital volume causes acquired esotro-pia. GOR (globe/orbit volume ratio), an indicator of the degree of progression of this pathology, was investi-gated the relationships among easily obtained clinical parameters. In this retrospective study, 20 eyes from 10 acquired esotropia patients with high myopia but without abduction limitations were examined. The mean age of the patients was 63.7 ± 8.2 years (mean ± standard deviation). Volumes were measured on the three-dimen-sional fast imaging employing steady-state acquisition magnetic resonance imaging images using the vol-ume-measurement function. Correlations between GOR and the displacement angle of the globe (DA), axial length (AL), and equatorial diameter (ED) were investigated. Mean DA, AL, ED, and GOR values were 107.5 ± 8.5°, 28.86 ± 1.92 mm, 25.00 ± 1.16 mm, and 0.36 ± 0.05, respectively. Only AL was correlated with GOR (p < 0.0001, R2 = 0.6649); DA (p = 0.30, R2 = 0.0633) and ED (p = 0.91, R2 = 0.0008) were not. AL was the only clinically available parameter to indicate globe/orbit volume imbalances in acquired esotropia with high myopia but without abduction limitation. AL may be important for the clinical assessment of the progression of this pathology

Shape analysis of rectus extraocular muscles with age and axial length using anterior segment optical coherence tomography

Purpose This study aimed to evaluate the shape of the extraocular muscles (EOMs) in normal subjects using the en-face images of anterior segment optical coherence tomography (AS-OCT). The EOM insertion and the direction of the muscle fibers were investigated. Subjects and methods A total of 97 healthy normal subjects (194 eyes) at Okayama University Hospital (age, 47.1±21.5 years; range, 8–79 years) participated in the study. A series of 256 tomographic images of the rectus EOMs were captured using the C-scan function of the AS-OCT (CASIA2, TOMEY Co., Japan), and the images were converted to en-face images in multi-TIFF format. The anterior chamber angle to EOM insertion distance (AID) and the angle of the muscle fibers from the insertion site (angle of muscles) were measured from the images. The correlations of AID and angle of muscles with age and axial length were investigated and evaluated. Results AID and angle of muscles were significantly correlated with age or axial length in some EOMs. The AIDs of medial rectus (MR) (P = 0.000) and superior rectus (SR) (P = 0.005) shortened with age. The AIDs of MR (P = 0.001) and inferior rectus (IR) (P = 0.035) elongated with axial length, whereas lateral rectus (LR) (P = 0.013) shortened. The angles of MR (P = 0.001) and LR (P = 0.000) were found to have a more downward direction toward the posterior in older subjects. Conclusion En-face images can be created by AS-OCT, and the shape of the EOMs in normal subjects using these image measurements was available. With the ability to assess the EOMs, AID and angle of muscles are expected give useful information for treating and diagnosing strabismus-related diseases

Congenital Multiple Ocular Motor Nerve Palsy Complicated by Splitting of the Lateral Rectus Muscle

We report a case of congenital multiple ocular motor nerve palsy combined with splitting of the lateral rectus muscle (LR). A 59-year-old Japanese female was investigated for worsening esotropia after corrective surgery. She presented with left hypertropia (35Δ) and esotropia (45-50Δ). Orbital magnetic resonance imaging (MRI) showed reduced belly sizes in the superior rectus, inferior rectus, and superior oblique muscles and splitting of the LR, extending from the origin to the belly, in the left eye. Splitting of the LR belly was detected on MRI in a case of congenital multiple ocular motor nerve palsy

Lights-out Surgery for Strabismus Using a Heads-Up 3D Vision System

During strabismus surgery using illumination from a light source, patients complain of photophobia. The NGENUITYⓇ (Alcon) system is equipped with a high-dynamic-range (HDR) camera. A 4K display viewed by wearing circularly polarized glasses provides clear three-dimensional images of the operative field. A light source is usually required for surgeries of the anterior segment (including strabismic surgery), but the digital processing function of the NGENUITYⓇ system allows image display in relatively dark regions even without a light source. We devised a novel ‘lights-out’ surgery that does not use a microscope’s light source, and we examined the usefulness of this technique in 2 cases of strabismic surgery. We performed strabismus surgery using the NGENUITYⓇ system in two patients between January and June 2018. The HDR function was used, and the aperture was opened to the maximum while the gain was adjusted. Surgery was conducted without using the microscope’s light source. We report the 2 cases’ results and evaluate the novel method. The surgeries were performed without problem even though the microscope’s light source was not used. The patients’ photophobia was alleviated. Lights-out surgery is a potentially useful modality for strabismus surgery

Risk factors for excessive postoperative exo-drift after unilateral lateral rectus muscle recession and medial rectus muscle resection for intermittent exotropia

Background: To detect significant factors associated with excessive postoperative exo-drift in young patients with intermittent exotropia who had undergone unilateral lateral rectus muscle recession and medial rectus muscle resection. Methods: We retrospectively examined the records of 64 consecutive patients Results: Younger patients (P = 0.007), and those with larger preoperative exo-deviation at distance (P = 0.033), a lower incidence of peripheral fusion at distance (P = 0.021) or a greater postoperative initial eso-deviation (P = 0.001), were significantly more likely to have an excessive postoperative exo-drift (> 20 prism diopters). Univariate analysis revealed significant associations between excessive postoperative exo-drift and age at surgery (P = 0.004), preoperative exo-deviation at distance (P = 0.017) and postoperative initial eso-deviation at distance (P Conclusions: Postoperative exodrift in unilateral RR is predicted by the initial postoperative eso-deviation, which may offset the overcorrection. However, the exo-drift is greater in cases with a large preoperative exo-deviation and/or at a younger age, and should be followed carefully