77 research outputs found

    Increase of Recognizable Label Number with Optical Passive Waveguide Circuits for Recognition of Encoded 4- and 8-Bit BPSK Labels

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    Optical label processing is expected to reduce power consumption in label switching network nodes. Previously, we proposed passive waveguide circuits for the recognition of BPSK labels with a theoretically infinite contrast ratio. The recognizable label number was limited to four and eight for 4-bit and 8-bit BPSK labels, respectively. In this paper, we propose methods to increase the recognizable label number. The proposed circuits can recognize eight and sixteen labels of 4-bit BPSK codes with a contrast ratio of 4.00 and 2.78, respectively. As 8-bit BSPK codes, 64, 128, and 256 labels can be recognized with a contrast ratio of 4.00, 2.78, and 1.65, respectively. In recognition of all encoded labels, that is, 16 and 256 labels for 4-bit and 8-bit BPSK labels, a reference signal is employed to identify the sign of the optical output signals. The effect of phase deviation and loss along the optical waveguides of the devices is also discussed

    Ambient-pressure molecular superconductor with a superlattice containing layers of tris(oxalato)rhodate enantiomers and 18-crown-6

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    We report a novel multilayered organic-inorganic hybrid material, β”-(BEDT-TTF)2[(H2O)(NH4)2Rh(C2O4)3].18-crown-6. This is the first molecular superconductor to have a superlattice with layers of both BEDT-TTF and 18-crown-6, and also the first with the anion tris(oxalato)rhodate. This is the 2D superconductor with the widest gap between conducting layers where only a single donor packing motif is observed (β”). The strong 2D nature of this system strong-ly suggests that the superconducting transition is a KT transition. A superconducting Tc of 2.7 K at ambient pressure was found by transport and 2.5 K by magnetic susceptibility measurements

    Tumor size before image-guided brachytherapy is an important factor of local control after radiotherapy for cervical squamous cell carcinoma: analysis in cases using central shielding

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    We analyzed the local control (LC) of cervical squamous cell carcinoma treated by computed tomography (CT)-based image-guided brachytherapy (IGBT) using central shielding (CS). We also examined the value of tumor diameter before brachytherapy (BT) as a factor of LC. In total, 97 patients were analyzed between April 2016 and March 2020. Whole-pelvic (WP) radiotherapy (RT) with CS was performed, and the total pelvic sidewall dose was 50 or 50.4 Gy; IGBT was delivered in 3-4 fractions. The total dose was calculated as the biologically equivalent dose in 2 Gy fractions, and distribution was modified manually by graphical optimization. The median follow-up period was 31.8 months (6.3-63.2 months). The 1- and 2-year LC rates were 89% and 87%, respectively. The hazard ratio was 10.11 (95% confidence interval: 1.48-68.99) for local recurrence in those with a horizontal tumor diameter >= 4 cm compared to those with = 4 cm, different treatment strategies such as employing interstitial-BT for dose escalation may be necessary

    Power generation characteristics of pulse jet rechargeable direct carbon fuel cells at different isooctane fuel supply frequency

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    INTRODUCTION Our research group previously proposed a new type of a direct carbon fuel cell (DCFC) called a rechargeable direct carbon fuel cell (RDCFC), which uses as fuel the solid-state carbon deposited on the electrode [1~6]. In a typical RDCFC, lower hydrocarbons such as propane are the supplied fuel, and deposition of the solid-state carbon (charging) into the anode is done by pyrolysis. In an RDCFC, this charging method causes several problems, such as low carbon extraction efficiency and batch-type rather than continuous operation. Our research group thus developed a pulse jet RDCFC because a constant power density can be maintained by supplying small amounts of high energy density liquid fuel by a pulse jet while generating electricity and continuous power generation by repeating the charging and power generation at short intervals. In addition, in a pulse jet RDCFC, deterioration of anodes due to carbon is minimized by frequent carbon removal and high energy conversion efficiency by utilizing hydrogen, methane, and other hydrocarbons as well as the solid-state carbon generated by the pyrolysis of liquid fuel. In a pulse jet RDCFC, the frequency at which isooctane fuel is supplied influences the power generation characteristics. When this supply frequency is increased, the power generation characteristics of a pulse jet RDCFC are thought to change to those of a flow-type SOFC. In this study, the effect of a supply frequency of isooctane on power generation characteristics of a pulse jet RDCFC was investigated

    Evaluation of Setup Errors at the Skin Surface Position for Whole Breast Radiotherapy of Breast Cancer Patients

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    We used image-processing software to analyze the setup errors at the skin surface position of breast cancer patients (n=66) who underwent post-operative whole breast irradiation at our hospital in 2014-2015. The sixty-six digital reconstructed radiographs (DRR) were created at the treatment planning for each patient. The lineacgraphies (n=377) were taken after the patients’ setup during radiotherapy. The lineacgraphies and DRR were superimposed at the skin surface position for each patient with the image-processing software. We measured the deviations of the isocenters for the nipple-lung (X) direction and craniocaudal (Y) direction and the deviation of the rotation angle of the XY axes between the lineacgraphy and DRR on the superimposed images. The systematic error (μ, Σ) and random error (σ) were calculated from the X and Y deviations and rotation angle deviation. The μ of X, Y, and rotation angle were 0.01 mm, −1.2 mm, and 0.05°, respectively. The Σ of X, Y, and rotation angle were 1.8 mm, 1.5 mm, and 0.9°, respectively. The σ of X, Y, and rotation angle were 2.0 mm, 1.5 mm, and 1.0°, respectively. Our analyses thus revealed that evaluations using image-processing software at the skin surface position in routine breast radiotherapy result in sufficiently small setup errors

    New field‑in‑field with two reference points method for whole breast radiotherapy: Dosimetric analysis and radiation‑induced skin toxicities assessment

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    The usefulness of the field‑in‑field with two reference points (FIF w/ 2RP) method, in which the dose reference points are set simultaneously at two positions in the irradiation field and the high‑dose range is completely eliminated, was examined in the present study with the aim of decreasing acute skin toxicity in adjuvant breast radiotherapy (RT). A total of 573 patients with breast cancer who underwent postoperative whole breast RT were classified into 178 cases with wedge (W) method, 142 cases with field‑in‑field without 2 reference points (FIF w/o 2RP) method and 253 cases with FIF w/ 2RP method. Using the FIF w/ 2RP method, the high‑dose range was the lowest among the three irradiation methods. The planning target volume (PTV) V105% and the breast PTV for evaluation (BPe) V105% decreased to 0.09 and 0.10%, respectively. The FIF w/ 2RP method vs. the FIF w/o 2RP method had a strong association (η) with PTV V105% (η=0.79; P<0.001) and BPe V105% (η=0.76; P<0.001). The FIF w/ 2RP method had a significant impact on lowering the skin toxicity grade in weeks 3 and 4, and increasing the occurrence of skin toxicity grade 0. The FIF w/ 2RP method vs. the W method had a moderate association with skin toxicity grade at week 3 (η=0.49; P<0.001). Using the FIF w/ 2RP method, the high‑dose range V105% of the target decreased to 0%, and skin adverse events were decreased in conjunction. For patients with early‑stage breast cancer, particularly patients with relatively small‑sized breasts, the FIF w/ 2RP method may be an optimal irradiation method

    Investigation into the Effect of Breast Volume on Irradiation Dose Distribution in Asian Women with Breast Cancer

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    Reports on irradiation dose distribution in breast cancer radiotherapy with sufficient sample size are limited in Asian patients. Elucidating dose distribution in Asian patients is particularly important as their breast volume differs compared to patients in Europe and North America. Here, we examined dose distribution in the irradiation field relative to breast volume for three irradiation methods historically used in our facility. We investigated the influence of breast volume on each irradiation method for Asian women. A total of 573 women with early-stage breast cancer were treated with breast-conserving surgery and adjuvant radiotherapy. Three methods were compared: wedge (W), field-in-field (FIF), and wedge-field-in-field (W-FIF). In patients with small breast volume, FIF decreased low- and high-dose areas within the planning target volume, and increased optimal dose area more than W. In patients with medium and large breast volumes, FIF decreased high-dose area more than W. The absolute values of correlation coefficients of breast volume to low-, optimal-, and high-dose areas and mean dose were significantly lower in FIF than in W. The correlation coefficients of V107% were 0.00 and 0.28 for FIF and W, respectively. FIF is an excellent irradiation method that is less affected by breast volume than W in Asian breast cancer patients
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