92 research outputs found

    A New pH-ISFET Based Dissolved Oxygen Sensor

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    A new dissolved oxygen sensor based on pH-ISFET has been discussed. A platinum working electrode surrounding a pH-sensing gate of the pH-ISFET electrolyzes dissolved oxygen, resulting in a corresponding pH change. The pH-ISFET can determine dissolved oxygen concentration through detecting this pH change. --Summar

    Miniaturized ISFET Glucose Sensor Including a New Structure Actuation System

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    A new principle of an amperometric actuation technique was incorporated in the ISFET glucose sensor. The ISFET is fabricated by the CMOS process and the platinum working electrode is deposited by the lift-off process. A sensor with a specially designed ladder type working electrode exhibits improved operation in response time, response magnitude and detection range. An expectation concerning the reduction of sensor size is also discussed

    Configuration for Micro pH Sensor

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    A fully integrated pH sensor with a built-in reference electrode is proposed. An iridium oxide microelectrode and a pH-insensitive field-effect transistor are used as a pH sensor and a reference electrode, respectively. The sensitivity of the proposed device matches well with the estimated value to within 0.3 mV/pH deviation

    Clinical Impact of Tumor Regression Grade after Preoperative Chemoradiation for Locally Advanced Rectal Cancer: Subset Analyses in Lymph Node Negative Patients

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    BACKGROUND: We investigated the prognostic significance of tumor regression grade (TRG) after preoperative chemoradiation therapy (preop-CRT) for locally advanced rectal cancer especially in the patients without lymph node metastasis. METHODS: One-hundred seventy-eight patients who had cT3/4 tumors were given 5,040 cGy preoperative radiation with 5-fluorouracil/leucovorin chemotherapy. A total mesorectal excision was performed 4-6 weeks after preop-CRT. TRG was defined as follows: grade 1 as no cancer cells remaining; grade 2 as cancer cells outgrown by fibrosis; grade 3 as a minimal presence or absence of regression. The prognostic significance of TRG in comparison with histopathologic staging was analyzed. RESULTS: Seventeen patients (9.6%) showed TRG1. TRG was found to be significantly associated with cancer-specific survival (CSS; P = 0.001) and local recurrence (P = 0.039) in the univariate study, but not in the multivariate analysis. The ypN stage was the strongest prognostic factor in the multivariate analysis. Subgroup analysis revealed TRG to be an independent prognostic factor for the CSS of ypN0 patients (P = 0.031). TRG had a stronger impact on the CSS of ypN (-) patients (P = 0.002) than on that of ypN (+) patients (P = 0.521). In ypT2N0 and ypT3N0, CSS was better for TRG2 than for TRG3 (P = 0.041, P = 0.048), and in ypN (-) and TRG2 tumors, CSS was better for ypT1-2 than for ypT3-4 (P = 0.034). CONCLUSION: TRG was found to be the strongest prognostic factor in patients without lymph node metastasis (ypN0), and different survival was observed according to TRG among patients with a specific histopathologic stage. Thus, TRG may provide an accurate prediction of prognosis and may be used for f tailoring treatment for patients without lymph node metastasis.ope

    Development of tricuspid regurgitation late after left-sided valve surgery: a single-center experience with long-term echocardiographic examinations

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    OBJECTIVES: This study sought to investigate the incidence and identify the predictors of significant tricuspid regurgitation (TR) development long after left-sided valve surgery. METHODS: Of 615 patients who underwent surgery for left-sided valve disease between 1992 and 1995, 335 patients without significant TR who completed at least 5 years of clinical and echocardiographic follow-up were enrolled. Late significant TR development was assessed by echocardiography with a mean follow-up duration of 11.6 +/- 2.1 years. RESULTS: Significant late TR was found in 90 patients (26.9%). Patients with late TR showed an advanced age (47.6 +/- 13.4 vs 44.3 +/- 13.2 years, P = .04), a higher prevalence of preoperative atrial fibrillation (83.3 vs 46.5%, P < .001), a greater left atrial dimension (56.9 +/- 13.2 vs 52.4 +/- 11.5 mm, P = .006), and a higher prevalence of prior valve surgery (40.0 vs 25.3%, P = .01). In addition, late TR occurred more frequently in patients who had undergone mitral valve surgery than in those who did not (93.3 vs 72.2%, P < .001). However, multivariate analysis showed that the presence of preoperative atrial fibrillation (odds ratio 5.37; 95% CI 2.71-10.65; P < .001) was the only independent factor of late TR development. Patients who developed late TR had a lower event-free survival rate than those who did not (P = .03). CONCLUSIONS: The development of significant TR long after left-sided valve surgery is not uncommon with an estimated incidence of 27% and is closely associated with a poor prognosis. The presence of preoperative atrial fibrillation was identified as the only independent predictor of the development of late TR
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