AUTOMATIC STEERING CONTROL OF RICE TRANSPLANTER (PART 2) : Control Method

田植機の自動操向制御の一手段として, 既に植え付けられた苗列を検出し, それに沿ってならい操向制御を行うことを目的として, 苗検出回路の改良と, 記憶・論理回路による制御方式の試行を行った。1) 検出回路は, OPアンプによる非反転増幅器により, 苗の抵抗を電圧に変えて検出する方式である。この回路の検出限界を固定抵抗を用いて測定したところ, 約33MΩであった。2) 検出信号は比較回路でオン・オフ信号に変換された後, 単安定マルチ・バイブレータをトリガし, 一定幅(0.1秒)のパルスが出力される。3) このパルスをタイミング・パルスとして, シフト・レジスタを用いた記憶回路で, 現在検出中の苗の5株前までの田植機の状態を保持し, 論理回路で論理演算を行って, 田植機の左旋回, 直進, 右旋回を決定する。4)この検出回路により, 苗の茎部を接触した場合は100%, 葉部を接触した場合でも約60%の検出能力があることが判った。5)記憶回路及び論理回路は, ほぼ初期の目的は達成でき, 田植機のずれが大きくなれば, 制御出力パルスの時間が長くなり, 走行速度が速くなるにつれ出力パルスの幅が短かくなる。 / This research was investigated as a method for the automatic steering of rice transplanter. It is the purpose of this research that the rice transplanter is steered automatically along the plant row which is transplanted previously. In this report, the detecting method mentioned in the previous report was improved and the controlling method by using memory and logical circuit was tried. (1) The detecting method was as follows. The electrical resistance of rice plant was converted to DC voltage by a non-inverting buffer amplifier with 741 type operational amplifier and the rice plant was detected. The detecting limit of this circuit was about 33MΩ. This value was extended more than the previous report. (2) The detected signal was converted to ON-OFF signal by a comparator, and it was triggered a monostable multivibrator IC. So the IC generated a fixed width pulse (0.1 second) when the sensor detected a rice plant. (3) The memory circuit held the condition of rice transplanter. This circuit was consisted in 5 bits serial-in, parallel-out shift register, so the rice plants of 5 hills were memorized and shifted by the timing pulse generated at a monostable multivibrator IC. The left turn, straight running, and right turn of transplanter was decided by the logical operations of the output signal of shift registers. (4) The memory and logical circuits almost achieved the initial purpose. If the error of transplanter was large, the holding time of pulse which controlled the transplanter became long. If the traveling speed of transplanter was fast, the pulse width became short, so the contolling time of transplanter changed according to the error and the traveling speed

Long-Term Serial Follow-Up of Pulmonary Artery Size and Wall Shear Stress in Fontan Patients

Pulmonary arterial (PA) flow is abnormal after the Fontan operation and is marked by a lack of pulsatility. We assessed the effects of this abnormal flow on the size and function of the PA’s in Fontan patients in long-term serial follow-up. Twenty-three Fontan patients with serial follow-up were included. Median age was 11.1 (9.5–16.0) years at baseline and 15.5 (12.5–22.7) years at follow-up. Median follow-up duration was 4.4 (4.0–5.8) years. Flow and size of the left pulmonary artery were determined using phase-contrast MRI. From this wall shear stress (WSS), distensibility and pulsatility were determined. A group of healthy peers was included for reference. Flow and pulsatility were significantly lower in patients than in controls (p < 0.001). Mean area was comparable in patients and controls, but distensibility was significantly higher in controls (p < 0.001). Mean and peak WSS were significantly lowe

Resectability and Ablatability Criteria for the Treatment of Liver Only Colorectal Metastases:Multidisciplinary Consensus Document from the COLLISION Trial Group

The guidelines for metastatic colorectal cancer crudely state that the best local treatment should be selected from a 'toolbox' of techniques according to patient- and treatment-related factors. We created an interdisciplinary, consensus-based algorithm with specific resectability and ablatability criteria for the treatment of colorectal liver metastases (CRLM). To pursue consensus, members of the multidisciplinary COLLISION and COLDFIRE trial expert panel employed the RAND appropriateness method (RAM). Statements regarding patient, disease, tumor and treatment characteristics were categorized as appropriate, equipoise or inappropriate. Patients with ECOG≤2, ASA≤3 and Charlson comorbidity index ≤8 should be considered fit for curative-intent local therapy. When easily resectable and/or ablatable (stage IVa), (neo)adjuvant systemic therapy is not indicated. When requiring major hepatectomy (stage IVb), neo-adjuvant systemic therapy is appropriate for early metachronous disease and to reduce procedural risk. To downstage patients (stage IVc), downsizing induction systemic therapy and/or future remnant augmentation is advised. Disease can only be deemed permanently unsuitable for local therapy if downstaging failed (stage IVd). Liver resection remains the gold standard. Thermal ablation is reserved for unresectable CRLM, deep-seated resectable CRLM and can be considered when patients are in poor health. Irreversible electroporation and stereotactic body radiotherapy can be considered for unresectable perihilar and perivascular CRLM 0-5cm. This consensus document provides per-patient and per-tumor resectability and ablatability criteria for the treatment of CRLM. These criteria are intended to aid tumor board discussions, improve consistency when designing prospective trials and advance intersociety communications. Areas where consensus is lacking warrant future comparative studies.</p

Volumetric Arterial Wall Shear Stress Calculation Based on Cine Phase Contrast MRI

PurposeTo assess the accuracy and precision of a volumetric wall shear stress (WSS) calculation method applied to cine phase contrast magnetic resonance imaging (PC-MRI) data. Materials and MethodsVolumetric WSS vectors were calculated in software phantoms. WSS algorithm parameters were optimized and the influence of spatial resolution and segmentation was evaluated. Subsequently, 2D cine PC-MRI data in the carotid and the aorta at varying spatial resolutions were obtained (n=2) and compared with the simulations. Finally, volumetric WSS was calculated in 3D cine PC-MRI data of the carotid bifurcation and the aorta (n=6). ResultsWe found that at least 8 voxels across the diameter are required to obtain a WSS accuracy of 5% and a precision of 20% in software phantoms. Systematic WSS quantification errors up to 40% were found in the case of segmentation errors. The in vivo measurements using 2D cine PC-MRI exhibited WSS increase at increasing spatial resolutions, similar to the results in software phantoms. Volumetric WSS vectors were successfully calculated in three healthy carotid bifurcations and aortas. ConclusionThe effects of resolution and segmentation on the accuracy and precision of the WSS algorithm were quantified. We were able to calculate volumetric WSS in the carotid bifurcation and the aorta. J. Magn. Reson. Imaging 2015;41:505-516.(c) 2013 Wiley Periodicals, In