117 research outputs found

    Automated eye disease classification method from anterior eye image using anatomical structure focused image classification technique

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    This paper presents an automated classification method of infective and non-infective diseases from anterior eye images. Treatments for cases of infective and non-infective diseases are different. Distinguishing them from anterior eye images is important to decide a treatment plan. Ophthalmologists distinguish them empirically. Quantitative classification of them based on computer assistance is necessary. We propose an automated classification method of anterior eye images into cases of infective or non-infective disease. Anterior eye images have large variations of the eye position and brightness of illumination. This makes the classification difficult. If we focus on the cornea, positions of opacified areas in the corneas are different between cases of the infective and non-infective diseases. Therefore, we solve the anterior eye image classification task by using an object detection approach targeting the cornea. This approach can be said as "anatomical structure focused image classification". We use the YOLOv3 object detection method to detect corneas of infective disease and corneas of non-infective disease. The detection result is used to define a classification result of a image. In our experiments using anterior eye images, 88.3% of images were correctly classified by the proposed method.Comment: Accepted paper as a poster presentation at SPIE Medical Imaging 2020, Houston, TX, US

    Correlation between contrast sensitivity and higher-order aberration based on pupil diameter after cataract surgery

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    Takefumi Yamaguchi1,2, Kazuno Negishi1, Kazuhiko Ohnuma3, Kazuo Tsubota11Department of Ophthalmology, Keio University School of Medicine, Tokyo; 2Department of Ophthalmology, Ichikawa General Hospital, Tokyo Dental College, Chiba; 3Department of Medical System Engineering, Faculty of Engineering, Chiba University, Chiba, JapanBackground: The purpose of this study was to evaluate the correlation between contrast sensitivity and calculated higher-order aberrations based on individual natural pupil diameter after cataract surgery.Methods: This prospective study included 120 eyes from 92 patients who were randomized to receive one of four lenses, including three aspheric lenses (Acrysof SN60WF, Tecnis ZA9000, and Hoya Py60AD) and one spherical lens (Acrysof SN60AT). Contrast sensitivity, higher-order aberrations of the whole eye, and pupil diameter under photopic and mesopic conditions were measured 1 month postoperatively. Higher-order aberrations were decomposed into Zernike coefficients, calculated according to individual pupil diameter. The correlation between higher-order aberrations and contrast sensitivity was evaluated.Results: There were no significant differences in contrast sensitivity function between the four types of lenses under photopic conditions. However, the contrast sensitivity function and area under log contrast sensitivity function in the aspheric lenses were significantly better than in the spherical lens under mesopic conditions. Under mesopic conditions, spherical aberration in eyes with aspheric lenses was significantly lower than in eyes with spherical lenses (P < 0.05). Under photopic conditions, coma aberration had a significant negative correlation with contrast sensitivity at 12 cycles/degree. Under mesopic conditions, spherical aberration had a significant negative correlation with contrast sensitivity at 3, 6, and 12 cycles/degree with glare, and with contrast sensitivity at 6 and 18 cycles/degree without glare.Conclusion: In terms of influence on visual function, coma aberration may be more significant under photopic conditions and spherical aberration under mesopic conditions.Keywords: mesopic conditions, spherical aberration, wavefront, photopic and mesopic condition

    Displacement Sensing of an Active String Actuator Using a Step-Index Multimode Optical Fiber Sensor

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    A thin McKibben artificial muscle is a pneumatic actuator with an outer diameter of only 1.8 mm. We fabricated a string-shaped actuator called an "active string actuator," which achieves a high contractile displacement by accumulating thin McKibben artificial muscles. To control the displacement, the length of the active string actuator should be estimated. However, this is difficult because bulky and rigid sensors are unsuitable for the sensor element of the active string actuator. Therefore, in this study, we propose a new sensing method for estimating the length of an active string actuator. The proposed sensing system is simple and comprises only three components: a step-index multimode optical fiber, a light emitter, and a light receiver. A step-index multimode optical fiber was combined with the active string actuator, and the length was estimated from the change in the amount of light propagating in the optical fiber when the active string actuator was driven. Fundamental experiments were conducted in this study, and the results demonstrated that the optical fiber sensor value changed with the actuator length. This suggests that it is possible to estimate the displacement of an active string actuator using an optical fiber sensor

    Rectal Carcinoma with Heterotopic Bone: Report of a Case

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    Heterotopic bone is rarely present in malignant tumors of the gastrointestinal tract. We herein report a case of rectal adenocarcinoma with heterotopic bone. A 46-year-old Japanese male presented to our hospital with abdominal distension and constipation. Colonoscopic examination showed an ulcerated polypoid tumor of the rectum which nearly obstructed the rectal lumen. Abdominal computed tomography showed a tumor of the rectum with calcified deposits. Low anterior resection with lateral lymph node dissection was performed under the tentative diagnosis of rectal cancer. Histological examination of the resected specimen showed mucinous carcinoma of the rectum with heterotopic bone. One of the metastatic lymph nodes dissected also showed heterotopic bone. In the present report, we describe this rare tumor and briefly review the pertinent literature regarding rectal cancer with heterotopic bone

    A Microchannel Device for Droplet Classification by Manipulation Using Piezoelectric Vibrator

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    Emulsion formulations should be monodispersed in terms of their stability. Therefore, there is a need for a device that can classify droplets of the desired size from polydispersed emulsions in a fluidized bed manufacturing system. In the previous study, we evaluated the fabrication of a droplet manipulation device using acoustic radiation forces through simulation using the finite element method. In this study, particle manipulation experiments using 1, 6, and 10 mu m polystyrene particles were first estimated and evaluated in comparison with their theoretical particle behavior. Based on the results we obtained, the driving conditions and droplet behavior were derived, and the droplet manipulation device using ultrasonic waves to shrink monodisperse emulsions was evaluated. As a result, the droplet classification effect in the microchannel was confirmed to be consistent with the droplet behavior prediction, and the microchannel structure with a constriction component improved its classification effect

    Accumulation and depuration profiles of PSP toxins in the short-necked clam Tapes japonica fed with the toxic dinoflagellate Alexandrium catenella

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    A toxic dinoflagellate responsible for paralytic shellfish poisoning (PSP), Alexandrium catenella (Ac) was fed to the short-necked clam Tapes japonica, and the accumulation and depuration profiles of PSP toxins were investigated by means of high-performance liquid chromatography with postcolumn fluorescence derivatization (HPLC-FLD). The short-necked clams ingested more than 99% of the Ac cells (4_107 cells) supplied once at the beginning of experiment, and accumulated a maximal amount of toxin (185 nmol/10 clams) after 12 h. The rate of toxin accumulation at that time was 23%, which rapidly decreased thereafter. Composition of the PSP toxin accumulated in the clams obviously different from that of Ac even 0.5 h after the cell supply, the proportion of C1+2 being much higher than in Ac, although the reason remains to be elucidated. In contrast, a higher ratio of gonyautoxin (GTX)1+4 than in Ac was detected in the toxin profiles of clam excrements. The variation in toxin composition derived presumably from the transformation of toxin analogues in clams was observed from 0.5 h, such as reversal of the ratio of C1 to C2, and appearance of carbamate (saxitoxin (STX), neoSTX and GTX2, 3) and decarbamoyl (dc) derivatives (dcSTX and dcGTX2, 3), which were undetectable in Ac cells. The total amount of toxin distributed over Ac cells, clams and their excrements gradually declined, and only 1% of supplied toxin was detected at the end of experiment

    An ultrasonic motor for cryogenic temperature using bolt-clamped Langevin-type transducer

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    In this study, a small ultrasonic motor driven under cryogenic temperature conditions has been fabricated and evaluated. Since transducer performance generally decreases at cryogenic temperatures, we designed and fabricated a bolt-clamped Langevin-type transducer for operation at cryogenic temperature. We simulated the influence of thermal stress on the transducer. The results from simulation were used to design the transducer, and it was then used to fabricate an ultrasonic motor for cryogenic temperature. The maximum diameter and the height of the motor are 30 mm and 38.7 mm. To enable the motor to be driven at cryogenic temperature, we evaluated the relationship between the contact pre-load and the lowest rotatable temperature. The motor's driving performance was evaluated at both room temperature and cryogenic temperatures. In a 4.5 K helium gas ambient, the rotation speed and starting torque were 133 rpm and 0.03 mu N m when the applied voltage was 50 Vp-p

    21セイキ ノ カンドウミャク インターベンション

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    Coronary intervention has come to achieve good results with the use of new devices, such as Rotablator (ROTA), new directional coronary atherectomy (DCA), and a special guide wire, even for lesions in which good results were not obtained with plain old balloon angioplasty. In the present study, we evaluated the initial results in patients who underwent ROTA procedures, coronary intervention for chronic total occlusion (CTO), and new DCA procedures in our hospital between January and December 2001. (1) There were 99 patients who underwent ROTA, with an average age of 68±12 years, a lesion length of 15.9±9.9 mm, a reference vessel diameter of 2.7±0.6 mm, and a success rate of 98%. Among these 99 patients, there were 82 patients (83%) with B2 or C type lesion, which is difficult to treat. (2) There were 61 patients with CTO who underwent coronary intervention, with an average age of 63±9 years, an occlusion length of 22.8±13.3 mm, a reference vessel diameter of 2.6±0.7 mm, and a success rate of 82%. (3) There were 5 patients who underwent DCA for ostial lesion of left anterior desending artery and the target lesion was successfully dilated in all these patients. These results indicated that new devices for coronary intervention have made it possible to treat a wider range of lesions, but restenosis still remains to be solved. In Europe and the U.S.A., restenosis is reported to have been drastically reduced by drug eluting stents, which are expected to be introduced in Japan in the future

    Transcriptional Activation of Low-Density Lipoprotein Receptor Gene by DJ-1 and Effect of DJ-1 on Cholesterol Homeostasis

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    DJ-1 is a novel oncogene and also causative gene for familial Parkinson’s disease park7. DJ-1 has multiple functions that include transcriptional regulation, anti-oxidative reaction and chaperone and mitochondrial regulation. For transcriptional regulation, DJ-1 acts as a coactivator that binds to various transcription factors, resulting in stimulation or repression of the expression of their target genes. In this study, we found the low-density lipoprotein receptor (LDLR) gene is a transcriptional target gene for DJ-1. Reduced expression of LDLR mRNA and protein was observed in DJ-1-knockdown cells and DJ-1-knockout mice and this occurred at the transcription level. Reporter gene assays using various deletion and point mutations of the LDLR promoter showed that DJ-1 stimulated promoter activity by binding to the sterol regulatory element (SRE) with sterol regulatory element binding protein (SREBP) and that stimulating activity of DJ-1 toward LDLR promoter activity was enhanced by oxidation of DJ-1. Chromatin immunoprecipitation, gel-mobility shift and co-immunoprecipitation assays showed that DJ-1 made a complex with SREBP on the SRE. Furthermore, it was found that serum LDL cholesterol level was increased in DJ-1-knockout male, but not female, mice and that the increased serum LDL cholesterol level in DJ-1-knockout male mice was cancelled by administration with estrogen, suggesting that estrogen compensates the increased level of serum LDL cholesterol in DJ-1-knockout female mice. This is the first report that DJ-1 participates in metabolism of fatty acid synthesis through transcriptional regulation of the LDLR gene
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