A three-dimensional haptic cataract tele-surgery simulation

Objective To discuss the application of posterior chamber and vitreous Cloquet's canal puncture in cataract surgery. Methods Our 285 eyes of 263 nonliquefied white intumescent cataracts cases without severe diseases were randomly divided into A and B group. Puncture of posterior chamber and 0.10-0.15 ml of liquid was sucked out of the vitreous Cloquet's canal firstly before continuous circular capsulorhexis in group A. Reduced capsulorhexis diameter combined with second are capsulorhexis, capsular puncturing, pressing nucleus to discharge of liquid and reverse capsulorhexis docking was performed according to the actual situation in group B. Continuous circular capsulorhexis successful level, iris damage grade, best corrected visual acuity on postoperative day 1 and corneal edema grade were observed. Results Imperfect capsulorhexis was in 22 eyes in group A and 63 eyes in group B. Radial cracks in anterior capsules was in 3 eyes in group A and 16 eyes in group B. Tangential capsulorhexis tear was in 19 eyes in group A and 47 eyes in group B. Iris damage of more than grade 1 was in 17 eyes in group A and 51 eyes in group B. The average operation time was (9.83±2.14) minutes in group A and (10.25±3.64) minutes in group B. The best corrected visual acuity better than 0.3 on postoperative day 1 was in 122 eyes in group A and 105 eyes in group B. Corneal edema over grade I occurred in 12 eyes in group A and 39 eyes in group B. Other complications including intraoperative and postoperative hyphema and severe inflammatory after operation were in 7 eyes in group A and 18 eyes in group B. Statistical study showed significant difference (P<0.01 or P<0.05), except for operation time. In addition of 143 eyes in group A, there were 140 eyes punctured successfully in one time and 3 eyes in two times in posterior chamber and vitreous Cloquet's canal puncture. Conclusion Puncture of posterior chamber and vitreous Cloquet's canal in cataract surgery can obviously relieve anterior lens capsule tension, increase anterior chamber operation space, reduce capsulorhexis difficulty and decrease operative injury and complications by reducing the pressure from the posterior chamber and vitreous cavity. In addition, according to relative higher successful puncture rate than previous reports, we postulated that not only posterior vitreous detachment but also anterior vitreous detachment which affected the canals of petit were more commonly appeared, especially at the anterior vitreous. Meanwhile, the capacity of Cloquet's canal expanded due to the vitreous liquefaction an concentration. Moreover we suggest that age-related cortical cataract should be classified into expanded type, cured type and basic type at least in order to instruct clinical treatment. Key words: Cataract; Type, clinical; Stage, clinical; Capsulorhexis, circular, continuous

Objective To evaluate the effect of distraction on continuous circular capsulorhexis (CCC) skill performance using a virtual reality simulator in expert and novice surgeons.Methods Expert (n =15) and novice (n =26) ophthalmic surgeons completed a standardized and validated surgical task 10 times on a virtual reality simulator (EyeSi).They then completed a dual task (cognitive task with arithmetic questions),after which they completed 10 attempts (take the last 5 attempts only) on the same module simulator module.The system would automatically evaluate the time of each procedure,the score of injuries of the surrounding tissue,the location,the form and size of the capsule and the mistakes during the procedure.Finally,results of the two groups were calculated with SPSS17.Results For experts,the difference between the Single Tasking and Dual Tasking was statistically significant only in the operation time.As for novice the score and time in CCC as well as the success rate of CCC,there was statistical significance between the single tasking and dual tasking.Conclusions A distractive cognitive task reduces the ability of novice surgeons to deal with that cognitive task.For experts,a distractive cognitive task doses not reduce their simulated surgical performance. Key words: Cataract; Continuous circular capsulorhexis; Distraction

Background With the progression of cortical cataract, the lens thickness and anterior chamber will change and may have significant influences on the structure and function of the eyes.A special measurement is needed to observe the anterior and posterior surface of lens and detailed angle structure, and to quantify these changes. Objective This study was to compare the lens thickness and angle structures by CASIA SS-1000 anterior segment optical coherence tomography (AS-OCT) in early and intumescent stage of cataract and quantify the ocular anatomical differences. Methods An observational study was performed.Fifty cortical cataract patients (87 eyes) of the early stage or the intumescent stage in the ophthalmology outpatient clinic of Daping Hospital from October 16 to October 30, 2015 were continuously enrolled in this research.The eyes were assigned to the early stage group (28 patients 44 eyes) and the intumescent stage group (22 patients 43 eyes) according to the slit lamp examination results.The average age was (56.46±12.90) years in the early stage group and (70.95±8.81) years in the intumescent stage group.With the use of CASIA SS-1000 AS-OCT measurements, lens thickness, angle opening distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA), trabecular-iris angle (TIA) and anterior chamber depth (ACD) were measured and compared between the two groups. Results Lens thickness was (4.438±0.487)mm in the early stage group and (5.094±0.451)mm in the intumescent stage group, with an average increase of (0.656±0.101)mm, showing a significant difference between the two groups (t=-6.513, P=0.000). ACD in the early stage group was (2.966±0.326)mm and (2.534±0.376)mm in the intumescent stage group, with an average decrease of (0.432±0.075)mm, showing a significant difference between the two groups (t=5.730, P=0.000). AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750 were all lower in the intumescent stage group than those in the early stage group, with significant differences between the two groups (all at P=0.000). Conclusions The lens was thicker, ACD was shallower and anterior angle was narrower in the intumescent stage than those in the early stage of cortical cataract patients.SS-1000 AS-OCT is efficiency with high definition, and is supposed to have promising prospect of clinical application. Key words: Anterior segment optical coherence tomography; Cortical cataract; Lens thickness; Anterior chamber

Objective To study the application of three-dimensional simulated surgical technique in precise hepatectomy. Methods From July 2009 to February 2010, 16 patients with primary liver cancer underwent preoperative simulated imaging and three-dimensional simulation of liver resection.The 3D extent of simulated hepatectomy and actual hepatectomy was compared and analyzed. Results The shape and the extent of the liver resected were very similar in the simulated and the actual hepatectomies. The mean differences in the length, breadth and depth of the remnant livers were 0. 6118 cm,0. 4490 cm and 0. 3199 cm, respectively. Conclusions Simulation hepatectomy could predict the extent of the actual liver resection, and provided accurate guidance and preoperative planning for precise hepatectomy. Key words: Three-dimensional simulated surgery techniques; Precise hepatectomy; Liver carcinoma

Posterior capsular opacification (PCO), also known as after-cataract, is the most frequent complication and the primary cause for visual decrease after extracapsular cataract surgery.At present, there is no effective way to treat PCO, so more attentions are focused on preventive reseaching of PCO and treatment methods.Although a variety of studies have increased our understanding of the pathogenesis of PCO, the cellular mechanisms responsible for PCO are still unclear.Cultured capsular bag model in vitro could effectively simulate lens capsular membrane and cells survival environment after cataract extraction and IOL implantation.However, lens capsular bag cultivation with different methods have their own characreristics.The material source, preparation methods of capsular bag model, characreristics of materials which maintain capsular bag contours and its application in PCO were reviewed. Key words: Posterior capsular opacity; Capsular bag model; Epithelial cells, lens; Cultivation

The spatial variability of soil organic carbon (SOC) is one of the reasons leading to uncertainty in the estimation of carbon stocks. Simulation and analysis research of SOC spatial distribution, especially the three-dimensional (3D) spatial distribution characteristics, is of great significance for revealing the soil nutrient and pollutant migration, the precise management of farmland and agricultural sustainable development. The 3D spatial distribution pattern of SOC was estimated using 3D ordinary Kriging with regard to the isotropy (3DOKI), 3D ordinary Kriging and 3D CoKriging coupling Markov with regard to anisotropy (3DOKA and 3DCKMA) in the region. Based on estimation results, the paper revealed 3D distribution pattern of regional SOC content. The mean root mean square error (RMSE), relative improvement (RI), the scatter diagram of SOC simulated and measured value and specific value coverage ratio were used to estimate the accuracy of different approaches, and the mean squared deviation ratio (MSDR) and the 3D variogram were used to evaluate model fitting effect and spatial local uncertainty. The results showed that 3D spatial distribution patterns of SOC content for the 3 kinds of estimation methods were basically the same, and the overall spatial distribution pattern was SOC content of the west and the north was higher, and that of the east and the south was relatively low. SOC contents of 5 layers (0-20, >20-40, >40-60, >60-80 and >80-100 cm) were 11.88±5.76, 10.08±4.89, 8.40±5.49, 7.83±5.89 and 7.17±5.22 g/kg, respectively. With the increase of soil depth, the SOC content of the patch gradually reduced. No matter which kind of method, the spatial distribution of SOC in different soil depth was similar, that was, the distribution characteristics of surface layer of the patch were also the embodiment of the deep soil layer. Compared to 3DOKI, the spatial search strategy and its parameters with regard to anisotropy were able to reduce defect (Bovine and central tendency effect) of Kriging method in a certain extent. The RMSE values for 3DOKI, 3DOKA and 3DCKMA were 3.1645, 2.0523 and 1.6215, respectively, so the RMSE value was the minimum for 3DCKAM, whose RI reached nearly 50%. Specific value coverage ratio for 3DOKI, 3DOKA and 3DCKMA were 33.12%, 57.83% and 76.15%, respectively, which was the largest for 3DCKMA method, whose MSDR value (1.4409) was the most close to 1, and variance was the least. The same position CoKriging method coupling Markov was more accurate, and its model fitting effect was the best, and uncertainty was the smallest, which could better highlight the volatility and reflect the specific value. The related research results of this paper will provide method reference for the regional soil properties, and provide technical guidance for the reasonable and scientific research of the spatial distribution pattern of regional SOC. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.

The reduction in size of modern electronic components and the accompanying reduction in size of computer casings requires optimized thermal designs for reliable electronic systems. Cooling problems related to electronic systems can be divided into the cooling of components mounted on heat sinks, components mounted on boards and environmental-level analysis. This paper will concentrate on the cooling of components with heat sinks using a finite difference simulation of the heat transfer in typical heat sink configurations. Various heat sinks were simulated to obtain the effect of the influencing parameters on the heat transfer at the boundaries. The simulated results were compared with experimental values over a range of heat dissipation in each type of heat sink. From the experiments, improved heat transfer models were developed at the boundaries to compensate for the influencing parameters such as heat sink orientation relative to gravity and by-pass air flow. It can be concluded from the results that three-dimensional simulations have distinct advantages over traditional design graphs to analyze the performance of heat sinks and should be common practice for the electronics design engineer.

Tabulated chemical kinetics for efficient and detailed simulations of diesel engine combustion

The goal of this paper is to perform simulations that capture fluid effects from small drops up to the propagation of large waves. To achieve this, we present a hybrid simulation method, that couples a two-dimensional shallow water simulation with a full three-dimensional free surface fluid simulation. We explain the approximations imposed by the shallow water model, and how to parametrize it according to the parameters of a 3D simulation. Each simulation is used to initialize double layered boundary conditions for the other one. The area covered by the 2D region can be an order of magnitude larger than the 3D region without significantly effecting the overall computation time. The 3D region can furthermore be easily moved within the 2D region during the course of the simulation. To achieve realistic results we combine our simulation method with a physically based model to generate and animate drops. For their generation we make use of the fluid turbulence model, and animate them with a simplified drag calculation. This allows simulations with relatively low resolutions.

A coaxial corrugated reflector and smooth drift segments structure of relativistic diffraction generator were studied using the full three-dimensional particle simulation software CHIPIC. The influences of the drift segments and reflector on the output power were analyzed. The relationship between the reflector position and the output power was explored. The simulation results show that appropriate reflector and drift segments can greatly improve the output power. After optimization of the structure parameters, when the input voltage was 480 kV, the average output power achieved 774.5 MW and the average power efficiency attained 32.3%.

Objective: To optimize the spherical aberrations of toric intraocular lens (IOL): to design toric IOLs with different spherical aberrations, and to study the rotation, the tolerance to decentration, and imaging rules. Methods: In this experimental study, the spherical aberrations of toric IOLs were optimized in the Hwey-Lan Liou model eye. The spherical structure, the curvature radius, and the thickness of the anterior and posterior surfaces of the toric IOLs, and the aspheric coefficients of the anterior surface of toric IOLs were optimized respectively. The targets was optimized to produce IOLs with -0.26 μm, -0.1 μm and 0 μm spherical aberrations. In the computer optical simulation system, the effect on the modulation transfer function (MTF) was evaluated when spherical and aspherical IOLs were decentrated in the horizontal direction with 0.25 mm, 0.50 mm and 0.75 mm at 3- and 5-mm pupil diameters. The effect on MTF was also evaluated when the two types of IOLs were rotated by 3°, 5° and 10° at 4-mm pupil diameter. Results: At the center, the aspherical toric IOL displayed a better image performance with the increased pupil diameter. When the decentration was 0.5 mm at 3-mm pupil diameters, the imaging quality of the -0.26 μm toric IOL decreased and was worse than that of 0 or -0.1 μm IOL. At 5-mm pupil diameter, when the decentration was 0.75 mm, the MTF of -0.26 μm toric IOL was close to that of the spherical toric IOL, while the MTF of toric IOL with 0 μm and -0.1 μm spherical aberration was slightly better than that of the spherical toric IOL. The MTF of aspherical toric IOLs was better than that of the spherical toric IOL with 3° to 5° rotation, but the curve was equal or even worse than that of the spherical toric IOL with 10° rotation in high spatial frequency. Conclusions: Toric IOLs with a spherical aberration of -0.26 μm have good imaging quality at the center but lower tolerance to decentration. The proper optimization of the spherical aberration of toric IOLs can improve the imaging quality of the model eye, while maintaining the tolerance for decentration and rotation errors. Optimized toric IOLs can attain better optical quality under comprehensive conditions. Key words: cataract; artificial lenses; astigmatism; cornea; decentration; rotation; modulation transfer function; model

Objective To evaluate the efficacy and safety of implanting a posterior chamber phakic intraocular lens to correct high myopia. Methods There were 117 eyes of 63 patients with high myopia. The range of preoperative myopia diopters was -5.25 - - 19.0D. The best corrected vision was ≥0.8 in 101 eyes and 0.5 - 0.6 in 15 eyes, and 〈 0.3 in one eye, The examine included uncorrected visual acuity （UC- VA） , corrected visual acuity, corneal endothelium, UBM,intraocular pressure, refraction, tonometry, kerame- ter, pachometer, axial length, depth of anterior chamber, horizontal corneal diameter （ white to white ）, and posterior mean evaluation after indirect ophthalmoscope examination. The posterior chamber phakic intraocu- lar lens manufactured with STAAR collamer was implanted though 3.0 mm sutureless temporal clear corneal incision under topical anesthesia. YAG laser peripheral iridectomy was performed before surgery to avoid pu- pil block glaucoma. The follow-up examination included visual acuity, refrection, tonometer, cornea, and space between crystal lens and IOL. Results 117 eyes implanting were successful , all eyes had a signifi- cant increase in uncorrected visual acuity, and a same or better corrected visual acuity, All eyes maintained a low negative power of refraction, but the patients managed most activities without spectacles. 2 case （ 2 eyes） were found cataract genesis under anterior capsular membrane. Conclusion The posterior chamber phakic IOL was predictable, safe, and efficacious in the correction of high myopic. Key words: High myopia ; Surgery ; Lens, artifical; Phakic eye

In this study, RELAP5-3D/K code is used to simulate the L2-5 test of Loss of Fluid Test (LOFT) facility. RELAP5-3D is a multi-dimensional reactor system thermal-hydraulic analysis code. In the present simulation, the core and downcomer are modeled as inconnected three dimensional components. The results of the simulation are compared with the results of the RELAP5-3D/K one-dimensional analysis. The purpose of this study is to qualify the margin of the safety analysis relatd to the design criteria of loss of coolant accident. The results show that the peak cladding temperatures (PCT) as predicted by the 3-D model of core and downcomer is about 180℉ lower than that of the 1-D model of the corresponding components. The results show that the predicted rise of cladding temperature in the blowdown phase of accident is higher in the case that core is simulated three-dimensionally. It is also demonstrated that the chimney effect in the 3-D core simulation is stronger than the case of 1-D simulation of core, which tends to lower the PCT in LOCA analysis. Chimney effect is referred as the coolant flow rate in a hot channel will increase by sucking in the coolant from nearby colder region. Modeling the downocmer three-dimensionally has a tendency to reduce the predicted crossflow in the annular region surrounded the core barrel. It implies that large amount of injected emergency cooling water will flow downward into the lower plenum. The initiation of core reflooding will be earlier for the core with three-dimensional simulation of downcomer.

In this paper an exhaust ejector of boiler based on the principle of injection is mentioned. A three-dimensional numerical simulation on the exhaust ejector of boiler was carried out by using software FLUENT. The effect of the induced pipe geometric parameters (the length and outlet width) on the inner flow field with different conditions was obtained. The simulation results show that some factors, such as velocity distribution, static pressure distribution at the outlet of the pipe caused by the induced pipe geometric variation, are significantly related to injection mass flow rate, and the optimum geometry which can leads to the most injection mass flow rate is h=0.05m, b=0.02m.

This work presents the study of a three-dimensional (3D) simulation of the concrete behaviour in a uni-axial compressive test and flexural test using discrete element modelling (DEM). The proposed numerical models are namely, unreinforced cylindrical concrete under a uni-axial compressive test, unreinforced concrete beam under three-point flexural test and lastly, steel reinforced concrete beam under four-point flexural test. Those models were built up with fish programming language and python programming language (see Appendix A1 for the code created) and run into a computer program namely Particle flow code (PFC 3D). The main aim of this paper is to validate those numerical models developed and to study the cracking initiation and failure process in order to understand the fracture behaviour of concrete. The particles were distributed using an algorithm that is based on the sieve test analysis. The parameters were set up in order to validate the numerical model with the experimental result. It was observed that all the three models developed show a strong correlation with the laboratory experiment in term of stress-strain response, load-displacement response, crack pattern and macroscopic cracks development. Once, the bond between the spheres is broken, it leads to the formation of microscopic cracks which is not visible in laboratory experiment. DEM can help to identify which part is more prone to the evolution of microscopic cracks to macroscopic cracks under the discrete fracture network. In addition to, the rosette plot allows identifying the orientation that leads to a significant amount of micro cracks which is essential for designing structures. From the observation recorded in this research, it was observed that DEM is capable to reproduce concrete behaviour both quantitatively and qualitatively. It is also possible to measure the strain energy stored in the linear contact bond and parallel bond. At yield point which corresponds to the maximum amount of microcracks recorded, that strain energy is released in the form of kinetic energy, frictional slip energy, energy of dashpot, local damping. This can be extended further to compute fracture energy in the future work. Hence, it can be concluded DEM can be used to study the heterogeneous nature of concrete and as well as randomness nature of the fracturing of concrete structure.