Realistic rainbow rendering considering light attenuation due to scattering and absorption in the atmosphere

情報処理学会 グラフィクスとCAD研究会 第134回研究発表会 発表資料 ; 開催場所:NHK放送技術研究所, 東京 ; 開催日:2009年2月16-17

Realistic rainbow rendering considering light attenuation due to scattering and absorption in the atmosphere

これまで、波動光学を考慮した虹のレンダリング法が開発され、過剰虹や異なる半径の水滴による虹の表示が行われてきた。しかし、大気中の水滴分布を一様と仮定しており、大気による光の散乱・減衰も考慮されていなかった。本研究では水滴ボリュームを設定し任意の密度と半径の水滴分布を考慮できるように改良した。また、光の減衰を考慮することで太陽高度の違いによる虹の色変化を表現できるようになった。さらに、街灯のような多様なスペクトル分布を持つ点光源も扱えるように拡張した。これらを考慮することで半径に応じて変化する虹や、高度によって色が変わる虹、また、点光源によって発生する特殊な形状の虹など様々な虹をレンダリングできるようになった。A method for rendering rainbows considering the wave optics has been developed and supernumerary rainbows and rainbows generated by different radii of raindrops were rendered. However, the method assumes that the distribution of the raindrops in the atmosphere is constant, and the attenuation of light due to the scattering and absorption in the atmosphere is not taken into account. We improved the rendering method considering both density and radius of raindrops using volume representation of raindrops. Considering attenuation of light, our method can render the change of rainbow color depending on solar altitude. In addition, we extended the method to be able to use a point light source with various spectrum distributions like streetlights. Our method can render various rainbows depending on radius of raindrops, the solar altitude, and light sources

Innovative suture technique for robotic hepaticojejunostomy: double-layer interrupted sutures

Purpose Biliary reconstruction remains a technically demanding and complicated procedure in minimally invasive hepatopancreatobiliary surgeries. No optimal hepaticojejunostomy (HJ) technique has been demonstrated to be superior for preventing biliary complications. This study aimed to investigate the feasibility of our unique technique of posterior double-layer interrupted sutures in robotic HJ. Methods We performed a retrospective analysis of a prospectively collected database. Forty-two patients who underwent robotic pancreatoduodenectomy using this technique between September 2020 and November 2022 at our center were reviewed. In the posterior double-layer interrupted technique, sutures were placed to bite the bile duct, posterior seromuscular layer of the jejunum, and full thickness of the jejunum. Results The median operative time was 410 (interquartile range [IQR], 388–478) min, and the median HJ time was 30 (IQR, 28–39) min. The median bile duct diameter was 7 (IQR, 6–10) mm. Of the 42 patients, one patient (2.4%) had grade B bile leakage. During the median follow-up of 12.6 months, one patient (2.4%) with bile leakage developed anastomotic stenosis. Perioperative mortality was not observed. A surgical video showing the posterior double-layer interrupted sutures in the robotic HJ is included. Conclusions Posterior double-layer interrupted sutures in robotic HJ provided a simple and feasible method for biliary reconstruction with a low risk of biliary complications

A Case of Nonunion Avulsion Fracture of the Anterior Tibial Eminence

Avulsion fracture of the anterior tibial eminence is an uncommon injury. If bone union does not occur, knee extension will be limited by impingement of the avulsed fragment and knee instability will be induced by dysfunction of the anterior cruciate ligament (ACL). This report describes a 55-year-old woman who experienced an avulsion fracture of the right anterior tibial eminence during recreational skiing. Sixteen months later, she presented at our hospital with limitation of right knee extension. Plain radiography showed nonunion of the avulsion fracture region, and arthroscopy showed that the avulsed fragment impinged the femoral intercondylar notch during knee extension. The anterior region of the bony fragment was debrided arthroscopically until the knee could be extended completely. There was no subsequent instability, and the patient was able to climb a mountain 6 months after surgery. These findings indicate that arthroscopic debridement of an avulsed fragment for nonunion of an avulsion fracture of the anterior tibial eminence is a minimally invasive and effective treatment for middle-aged and elderly patients with a low level of sports activity

Photo-realistic rendering of rainbows based on atmospheric optical phenomena

パターン認識・メディア理解研究会(PRMU 2009):光と色の解析・表現とその応用 発表資料 ; 開催地:広島大学 ; 開催日:2009年10月22-23

Prediction of Total Drug Clearance in Humans Using Animal Data: Proposal of a Multimodal Learning Method Based on Deep Learning

Research into pharmacokinetics plays an important role in the development process of new drugs. Accurately predicting human pharmacokinetic parameters from preclinical data can increase the success rate of clinical trials. Since clearance (CL) which indicates the capacity of the entire body to process a drug is one of the most important parameters, many methods have been developed. However, there are still rooms to be improved for practical use in drug discovery research; "improving CL prediction accuracy" and "understanding the chemical structure of compounds in terms of pharmacokinetics". To improve those, this research proposes a multimodal learning method based on deep learning that takes not only the chemical structure of a drug but also rat CL as inputs. Good results were obtained compared with the conventional animal scale-up method; the geometric mean fold error was 2.68 and the proportion of compounds with prediction errors of 2-fold or less was 48.5%. Furthermore, it was found to be possible to infer the partial structure useful for CL prediction by a structure contributing factor inference method. The validity of these results of structural interpretation of metabolic stability was confirmed by chemists

Predicting Total Drug Clearance and Volumes of Distribution Using the Machine Learning-Mediated Multimodal Method through the Imputation of Various Nonclinical Data

Pharmacokinetic research plays an important role in the development of new drugs. Accurate predictions of human pharmacokinetic parameters are essential for the success of clinical trials. Clearance (CL) and volume of distribution (Vd) are important factors for evaluating pharmacokinetic properties, and many previous studies have attempted to use computational methods to extrapolate these values from nonclinical laboratory animal models to human subjects. However, it is difficult to obtain sufficient, comprehensive experimental data from these animal models, and many studies are missing critical values. This means that studies using nonclinical data as explanatory variables can only apply a small number of compounds to their model training. In this study, we perform missing-value imputation and feature selection on nonclinical data to increase the number of training compounds and nonclinical datasets available for these kinds of studies. We could obtain novel models for total body clearance (CLtot) and steady-state Vd (Vdss) (CLtot: geometric mean fold error [GMFE], 1.92; percentage within 2-fold error, 66.5%; Vdss: GMFE, 1.64; percentage within 2-fold error, 71.1%). These accuracies were comparable to the conventional animal scale-up models. Then, this method differs from animal scale-up methods because it does not require animal experiments, which continue to become more strictly regulated as time passes

Surgical Strategies to Approaching the Splenic Artery in Robotic Distal Pancreatectomy

Background/Aim: Understanding different surgical approaches and anatomical landmarks adjacent to the splenic artery (SpA) is important for safe robotic distal pancreatectomy (RDP). Herein, we propose our standardized RDP techniques, focusing on these issues. Patients and Methods: Between April 2021 and April 2022, 19 patients who underwent RDP at our Institution were reviewed. Anatomical patterns of the SpA were classified into three types: Type 1, no pancreatic parenchyma on the root of the SpA; type 2, any pancreatic parenchyma on the root of the SpA; and type 3, dorsal pancreatic artery around the bifurcation of the common hepatic artery and SpA. Next, the surgical strategy for approaching the SPA was determined according to the location of the pancreatic transection line: On the superior mesenteric vein (SMV) or on the left side of the root of the SpA. Results: There were seven cases of type 1, nine cases of type 2, and three cases of type 3. When transecting the pancreas on the SMV, the SpA-first ligation technique was used for type 1 SpA anatomy, and the pancreas-first division technique was applied for types 2 and 3. In patients in whom the pancreas was transected at the left side of the root of the SpA, the SpA-first ligation technique was used. Conclusion: Our standardized surgical strategy based on anatomical landmarks and focusing on the approach to the SpA in RDP is demonstrated. Our strategy should help trainees approach the SpA and perform RDP safely

Gastroenteropancreatic neuroendocrine tumor of the accessory papilla of the duodenum: a case report

BackgroundContrary to the increasing incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs), GEP-NETs of the accessory papilla of the duodenum are extremely rare. Furthermore, there have been no recommendations regarding the treatment strategy for GEP-NETs of the accessory papilla of the duodenum. We present a case of GEP-NET of the accessory papilla of the duodenum successfully treated with robotic pancreatoduodenectomy.Case presentationA case of a 70-year-old complaining of no symptoms was diagnosed with GEP-NET of the accessory papilla of the duodenum. A 8-mm tumor was located at the submucosal layer with a biopsy demonstrating a neuroendocrine tumor grade 1. The patient underwent robotic pancreatoduodenectomy as curative resection for the tumor. The total operative time was 406 min with an estimated blood loss of 150 mL. The histological examination revealed a well-differentiated neuroendocrine tumor with low Ki-67 index (<1%). In the posterior areas of the pancreas, the lymph node metastases were detected. The patient was followed up for 6 months with no recurrence postoperatively.ConclusionsConsidering the potential risks of the lymph node metastases, the standard treatment strategy for GEP-NETs of the accessory papilla of the duodenum should be radical resection with pancreatoduodenectomy. Minimally invasive approach can be the alternative to the conventional open surgery