Side Wall Effects on the Hydrodynamics of a Floating Body by ImageGreen Function Based on TEBEM

A novel numerical model based on the image Green function and first-order Taylor expansion boundary element method(TEBEM), which can improve the accuracy of the hydrodynamic simulation for the non-smooth body, was developed to calculate the side wall effects on first-order motion responses and second-order drift loads upon offshore structures in the wave tank. This model was confirmed by comparing it to the results from experiments on hydrodynamic coefficients, namely the first-order motion response and second-order drift load upon a hemisphere, prolate spheroid, and box-shaped barge in the wave tank. Then,the hydrodynamics of the KVLCC2 model were also calculated in two wave tanks with different widths. It was concluded that this model can predict the hydrodynamics for offshore structures effectively, and the side wall has a significant impact on the firstorder quantities and second-order drift loads, which satisfied the resonant rule.

Estimation of chlorophyll content in Brassica napus based on unmanned aerial vehicle images

The chlorophyll content has a direct effect on photosynthesis of crops.In order to explore a quick and convenient method for estimating the chlorophyll content of Brassica napus and facilitate efficient crop monitoring,we measured the actual value of chlorophyll with a SPAD-502 chlorophyll detector,and collected aerial images of B.napus with an unmanned aerial vehicle(UAV)carrying a RGB camera in this study.The total number of 270samples collected images were divided into regions according to the planting conditions of different B.napus varieties in the field.Then,according to the empirical formula,there were 36 colors’characteristic parameters calculated and combined.To estimate the chlorophyll content of rape,189 samples were included in the modeling set,while the other 81 samples were enrolled in the validation set for testing the accuracy of this model.After the combination of R(red),G(green)and B(blue)color channels,the results showed that the color characteristics B/(R+G),b,B/G,(G-B)/(G+B),g-b were highly connected with the measured value of chlorophyll SPAD,and the correlation coefficient between the combination based on B/(R+G)and SPAD value was 0.747.With R2=0.805,RMSE=3.343,and RE=6.84%,the regression model created using random forest had superior outcomes,according to the model comparison.This study offers a new method for quickly estimating the amount of chlorophyll in rapeseed and a workable reference for crop monitoring using the UAV platform.

Mechanism of Dynamic Near-infrared Fluorescence Cholangiography of Extrahepatic Bile Ducts and Applications in Detecting Bile Duct Injuries Using Indocyanine Green in Animal Models

Fluorescence intraoperative cholangiography（IOC） is a potential alternative for identifying anatomical variation and preventing iatrogenic bile duct injuries by using the near-infrared probe indocyanine green（ICG）. However, the dynamic process and mechanism of fluorescence IOC have not been elucidated in previous publications. Herein, the optical properties of the complex of ICG and bile, dynamic fluorescence cholangiography and iatrogenic bile duct injuries were investigated. The emission spectrum of ICG in bile peaked at 844 nm and ICG had higher tissue penetration. Extrahepatic bile ducts could fluoresce 2 min after intravenous injection, and the fluorescence intensity reached a peak at 8 min. In addition, biliary dynamics were observed owing to ICG excretion from the bile ducts into the duodenum. Quantitative analysis indicated that ICG-guided fluorescence IOC possessed a high signal to noise ratio compared to the surrounding peripheral tissue and the portal vein. Fluorescence IOC was based on rapid uptake of circulating ICG in plasma by hepatic cells, excretion of ICG into the bile and then its interaction with protein molecules in the bile. Moreover, fluorescence IOC was sensitive to detect bile duct ligation and acute bile duct perforation using ICG in rat models. All of the results indicated that fluorescence IOC using ICG is a valid alternative for the cholangiography of extrahepatic bile ducts and has potential for measurement of biliary dynamics.

Altemeier perineal rectosigmoidectomy with indocyanine green fluorescence imaging for a female adolescent with complete rectal prolapse:A case report

BACKGROUND Rectal prolapse in young women is rare.Although laparoscopic ventral mesh rectopexy is the standard procedure because of its lower recurrence rate,postoperative infertility is a concern.Perineal rectosigmoidectomy(Altemeier procedure)is useful for these patients.However,the risk of anastomotic leakage should be considered.Recently,the usefulness of fluorescence imaging with indocyanine green(ICG)to prevent anastomotic leakage was reported.We report a case of an adolescent woman with complete rectal prolapse who underwent ICG fluorescence imaging-assisted Altemeier rectosigmoidectomy.CASE SUMMARY A 17-year-old woman who had a mental disorder was admitted to our hospital for treatment for water intoxication.The patient also suffered from rectal prolapse,approximately 3 mo before admission.She was referred to our surgical department because recurrent rectal prolapse could worsen her psychiatric disorder.Approximately 10 cm of complete rectal prolapse was observed.However,the mean maximum anal resting and constriction pressures were within normal limits on anorectal manometry.Because she had the desire to bear children in the future,she underwent Altemeier perineal rectosigmoidectomy to prevent surgery-related infertility.We performed ICG fluorescence imaging at the same time as surgery to reduce the risk of anastomotic leakage.Her postoperative course was uneventful,and the rectal prolapse was completely resolved.She continued to do well 18 mo after surgery,without recurrence of the rectal prolapse.CONCLUSION ICG fluorescence imaging-assisted Altemeier perineal rectosigmoidectomy is useful in preventing postoperative anastomotic leakage in young as well as elderly patients.

Minimally invasive surgery for gastro-oesophageal junction adenocarcinoma: Current evidence and future perspectives

Minimally invasive surgery is increasingly indicated in the management of malignant disease.Although oesophagectomy is a difficult operation,with a long learning curve,there is actually a shift towards the laparoscopic/thoracoscopic/robotic approach,due to the advantages of visualization,surgeon comfort(robotic surgery)and the possibility of the whole team to see the operation as well as and the operating surgeon.Although currently there are still many controversial topics,about the surgical treatment of patients with gastro-oesophageal junction(GOJ)adenocarcinoma,such as the type of open or minimally invasive surgical approach,the type of oesophago-gastric resection,the type of lymph node dissection and others,the minimally invasive approach has proven to be a way to reduce postoperative complications of resection,especially by decreasing pulmonary complications.The implementation of new technologies allowed the widening of the range of indications for this type of surgical approach.The short-term and long-term results,as well as the benefits for the patient-reduced surgical trauma,quick and easy recovery-offer this type of surgical treatment the premises for future development.This article reviews the updates and perspectives on the minimally invasive approach for GOJ adenocarcinoma.

3D laparoscopic anatomical hepatectomy guided by 2D real-time indocyanine green fluorescence imaging for hepatocellular carcinoma

Laparoscopic anatomical hepatectomy(LAH)for patients with hepatocellular carcinoma(HCC)has been advocated by many surgeons in the hope of producing better oncological outcomes.Two recent techniques,3D laparoscopic system and 2D real-time indocyanine green fluorescence imaging(r-ICG)guidance,are benefit for improving the operative precision of LAH in different aspects.However,these two techniques cannot be applied concomitantly because of the technical limitation.Although a new modern laparoscopic system with both 3D and indocyanine green(ICG)imaging mode has been designed,it has not been listed in many countries including China.Thus,we design a new procedure to perform the 3D LAH with 2D r-ICG guidance for HCCs with conventional laparoscopic systems.In this procedure,both 3D and 2D laparoscopic systems were used.A total of 11 patients with HCC received 3D laparoscopic right posterior sectionectomy(LRPS)with 2D r-ICG guidance.The right posterior Glissonian pedicle was clamped under the 3D vision.Then ICG solution was then intravenously administrated.The liver parenchyma was transected under the 3D vision and guided by 2D ICG vision simultaneously.There was no severe complications(Clavien-Dindo≥III)and operation related death.The 90-day mortality was also nil.By using this procedure,the advantages of two techniques,3D laparoscopic system and 2D r-ICG guidance,were combined so that LAH could be performed with more precision.However,it should be validated in more studies.

Nonlinear numerical simulation on extreme-wave kine-matics

A fully nonlinear numerical model based on a time-domain higher-order boundary element method （HOBEM） is founded to simulate the kinematics of extreme waves. In the model, the fully nonlinear free surface boundary conditions are satisfied and a semi-mixed Euler-Lagrange method is used to track free surface; a fourth-order Runga-Kutta technique is adopted to refresh the wave elevation and velocity potential on the free surface at each time step; an image Green function is used in the numerical wave tank so that the integrations on the lateral surfaces and bottom are excluded. The extreme waves are generated by the method of wave focusing. The physical experiments are carried out in a wave flume. On the horizontal velocity of the measured point, numerical solutions agree well with experimental results. The characteristics of the nonlinear extreme-wave kinematics and the velocity distribution are studied here.

An Efficient Model for Transient Surface Waves in Both Finite and Infinite Water Depths

A numerical model is developed to simulate fully nonlinear extreme waves in finite and infinite water-depth wave tanks. A semi-mixed Enlerian-Lagrangian formulation is adopted and a higher-order boundary element method in conjunction with an image Green function is used for the fluid domain. The botmdary values on the free surface are updated at each time step by a fourth-order Runga-Kutta time-marching scheme at each time step. Input wave characteristics are specified at the upstream boundary by an appropriate wave theory. At the downstream boundary, an artificial damping zone is used to prevent wave reflection back into the computational domain. Using the image Green function in the whole fluid domain, the integrations on the two lateral walls and bottom are excluded. The simulation results on extreme wave elevations in finite and infinite water-depths are compared with experimental results and second-order analytical solutions respectively. The wave kinematics is also discussed in the present study.