Approach to glaucoma diagnosis and prediction based on multiparameter neural network.

PURPOSE: To investigate the effect of comprehensive factor analysis on the relationship between glaucoma assessment and combined parameters including trans-laminar cribrosa pressure difference (TLCPD) and fractional pressure reserve (FPR). METHODS: The clinical data of 1029 patients with 15 indicators from the medical records of Beijing Tongren Hospital and 600 cases with 1322 indicators from Beijing Eye Research were collected. The doc2vec method was used to vectorize. The multivariate imputation by chained equations (MICE) method was used to interpolate. The original data combined with TLCPD, combined with FPR, and not combined parameters were respectively applied to train the neural network based on VGG16 and autoencoder to predict glaucoma and to evaluate the effect of combined parameters. RESULTS: The accuracy rates used to classify the glaucoma of the two sets reach over 0.90, and the precision rates reach 0.70 and 0.80 respectively. After using TLCPD and FPR for the autoencoder method, the accuracy rates are both close to 1.0, and the precision rates are 0.90 and 0.70 respectively. CONCLUSION: Using the combined parameters of FPR and TLCPD can effectively improve the diagnosis and prediction of glaucoma. Compared with TLCPD, FPR is more suitable for improving the effect of neural network for glaucoma classification.

Free-Standing Stable Silicon-Based Anode with Exceptional Flexibility Realized by a Multifunctional Structure Design in Multiple Dimensions.

Cyclized polyacrylonitrile (cPAN) with decently flexible, elastic, and conductive properties is a promising substrate or binder material for flexible devices. However, it is infeasible to accommodate the large volume expansion and contribute the exceptional rate capability of silicon anodes in lithium-ion batteries only counting on the limited elasticity and conductivity of cPAN. Herein, we report a robust silicon/carbon-cPAN-graphene (SC-CP-G) composite membrane with excellent flexibility based on a multifunctional structure design in multiple dimensions, which can be used as a free-standing integrated anode for lithium ion batteries. In this integrated electrode, silicon nanoparticles are encapsulated in porous carbon with in situ formed confined space, and the silicon/carbon particles are further embedded in cPAN nanofibers, which are inextricably interwoven with a reduced graphene oxide film, forming an interpenetrating network architecture. The unique hierarchical and functional structure design greatly improves the mechanical performance, cycling stability, and capacity accessibility of silicon electrodes, delivering a specific capacity of 1847 mA h g-1 at 2 A g-1 and a capacity retention of 87% after 150 cycles.

Preparation of Advanced Multi-Porous Carbon Nanofibers for High-Performance Capacitive Electrodes in Supercapacitors.

The booming demand for energy storage has driven the rapid development of energy storage devices such as supercapacitors, and the research on high-performance electrode materials, a key component of supercapacitors, has gained tremendous attention. In this research, phenolic resin-based multi-porous carbon nanofibers have been prepared by electrospinning, curing, carbonization and activation and then employed as advanced electrode materials in supercapacitors. We demonstrate that the material is nano-scale continuous fiber, and its surface has pore distribution of different sizes. It delivers a high specific capacitance of 242 F g-1 at a current density of 0.2 A g-1 and maintains 148 F g-1 even at a high current density of 20 A g-1. Moreover, it shows almost no capacitance decay at a current density of 2 A g-1 over 1000 cycles, demonstrating its great potential as high-performance electrodes in supercapacitors.

Branch flow distribution approach and its application in the calculation of fractional flow reserve in stenotic coronary artery.

OBJECTIVE: To calculate fractional flow reserve (FFR) based on computed tomography angiography (i.e., FFRCT) by considering the branch flow distribution in the coronary arteries. BACKGROUND: FFR is the gold standard to diagnose myocardial ischemia caused by coronary stenosis. An accurate and noninvasive method for obtaining total coronary blood flow is needed for the calculation of FFRCT. METHODS: A mathematical model for estimating the coronary blood flow rate and two approaches for setting the patient-specific flow boundary condition were proposed. Coronary branch flow distribution methods based on a volume-flow approach and a diameter-flow approach were employed for the numerical simulation of FFRCT. The values of simulated FFRCT for 16 patients were compared with their clinically measured FFR. RESULTS: The ratio of total coronary blood flow to cardiac output and the myocardial blood flow under the condition of hyperemia were 16.97% and 4.07 mL/min/g, respectively. The errors of FFRCT compared with clinical data under the volume-flow approach and diameter-flow approach were 10.47% and 11.76%, respectively, the diagnostic accuracies of FFRCT were 65% and 85%, and the consistencies were 95% and 90%. CONCLUSIONS: The mathematical model for estimating the coronary blood flow rate and the coronary branch flow distribution method can be applied to calculate the value of clinical noninvasive FFRCT.

The significance of SMARCB1 in the pathogenesis of renal cell carcinoma with rhabdoid features.

BACKGROUND: Renal cell carcinoma with rhabdoid features (RCC-RF) is an aggressive histologic variant in the adults and is usually unresponsive to standard chemotherapy. METHODS: Expression of SMARCB1/INI1 was examined in primary RCC-RF (n = 5). Stable INI1 with/without prostaglandin E2 receptor 1 (EP1) knockdown cell lines were created in the ACHN and 786-O RCC cell lines and measured for epidermal growth factor receptor (EGFR)-related signaling pathways. Chemosensitivity to targeted drugs in vitro was tested after knocking down of INI1 in both cell lines. The outcome of co-targeting of INI1 and EP1 in RCC was examined using a tumorigenicity assay. RESULTS: Expression of INI1 was markedly reduced at both transcriptional and translational levels in primary RCC-RF. Immunohistochemical expression of INI1 protein was lost in the nuclei of rhabdoid cells compared with conventional RCC (n = 8). Using two cell lines with different genetic background, we showed that knocking down of INI1 activates the EGFR signaling with up-regulated AKT and ERK pathways and sensitizes cancer cells to Erlotinib treatment in vitro. However, cell-line dependent effects were also demonstrated with reference to impact of INI1 or EP1 on cell growth, migration and response to Gefitinib or Everolimus treatment in vitro. CONCLUSION: Inactivation of INI1 may play a role in the pathogenesis of RCC-RF. Erlotinib is recommended in the management of patients with INI1-related RCC.

[In vivo experimental study of acute intraocular hypertension in rabbit based on particle image velocimetry technique].

At present, there are few in vivo experimental studies on anterior chamber flow field, and the relevant technologies are not mature. This study explores the experimental method and key techniques of particle image velocimetry (PIV) for the in vivo measurement of anterior chamber flow field with slow flow velocity in the rabbit with acute intraocular hypertension. The experimental process can be divided into three parts: model construction of rabbit eye with acute intraocular hypertension, in vivo eyeball preparation, and PIV setup. The following key techniques were mainly investigated: the optimal injection strategy of fluorescent particles and the correction strategy for image acquisition errors caused by the effects of image refraction and respiration. The results showed that the best injection method was that 15 µL of fluorescent particles solution was slowly injected into the anterior chamber through the lower part of iris and then the rabbit was released and waited for 13 h. In this way particles were completely distributed in the anterior chamber with the help of the aqueous humor circulation, and then in vivo PIV experiment could be performed. The eyeball should be covered with a square flume filled with ultrasonic coupling gel for the sake of imaging during the experiment. The Maximal Information Coefficient algorithm could be applied to correct the measured results before post-processing calculation. The results indicated that feasible injection strategy of fluorescent particles and the correction strategy for image acquisition are critical to obtain nice experiment effects for the in vivo PIV measurement of anterior chamber flow field in the rabbit with acute intraocular hypertension.

Computational Study on the Biomechanics of Pupil Block Phenomenon.

Pupil blocking force (PBF) can indicate the potential risk of pupil block (PB), which is considered as a main pathogenic factor of primary angle-closure glaucoma (PACG). However, the effect of PB on the PBF under different pupil diameters and iris-lens channel (ILC) distance was unknown. Besides, a simple and practical method to assess PBF has not been reported yet. In this study, 21 finite element models of eyes with various pupil diameters (2.4 mm-2.6 mm) and ILC (2 µm-20 µm) were constructed and were conducted to simulate aqueous humor flow by fluid-solid coupling numerical simulation. PBF in each model was calculated based on the numerical simulation results and was fitted using response surface methodology. The results demonstrated that ILC distance had a more significant effect than pupil diameter on PBF. With the decrease of ILC distance, the PBF increased exponentially. When the reduced distance was lower than 5 µm, the PBF exploded quickly, resulting in a high risk of iris bomb. The PBF also varied with pupil diameter, especially under the condition of narrow ILC. Both ILC distance and pupil diameter could explain more than 97% variation in PBF, and a second-order empirical model has been developed to be a good predictor of PBF. Based on the linear relationship between anterior chamber deformation and PBF, a threshold value of PBF was given to guide clinical decisions. This study could be used to investigate PACG pathological correlation and its pathogenesis, so as to provide a reference value for clinical diagnosis of PACG.

[Review of studies on the application of biomechanical factors in the evaluation of glaucoma].

There are so many biomechanical risk factors related with glaucoma and their relationship is much complex. This paper reviewed the state-of-the-art research works on glaucoma related mechanical effects. With regards to the development perspectives of studies on glaucoma biomechanics, a completely novel biomechanical evaluation factor -- Fractional Flow Reserve (FPR) for glaucoma was proposed, and developing clinical application oriented glaucoma risk assessment algorithm and application system by using the new techniques such as artificial intelligence and machine learning were suggested.

[Experimental study on the in vivo continuous measurement of pressure difference between the anterior and the posterior chambers].

A set of device for the in vivo measurement of the pressure difference between the anterior and the posterior chambers (PDAP) was designed to investigate the temporal varying rules of PDAP in the anterior segment of rabbit eyes. A platform was established for the in vivo measurement of PDPA according to the mechanism of joint implement. Rabbit models with high intraocular pressure (IOP) were constructed by means of injecting Carbomer into anterior chamber to increase IOP. The in vivo 24 hours continuous measurements of PDAP were performed for normal rabbit eye and eye with high IOP. The developed device could sensitively response to the small pressure difference in eye. The pressure difference in the normal rabbit eye varied with time, and the variation range during a whole day was 5.84-96.84 Pa which reflected the existence of physiological rule. For the rabbit eye with high IOP, pressure in anterior chamber was higher than that in posterior chamber which was in consistence with the theory of self-adaptation adjustment. The present study indicates that the approaches and device designed in this paper can well implement the measurement of PDAP as well as the temporal varying rules of PDAP in the anterior segment during a whole day.

Erratum to: Fluid and structure coupling analysis of the interaction between aqueous humor and iris.

[This corrects the article DOI: 10.1186/s12938-016-0261-3.].

Fluid and structure coupling analysis of the interaction between aqueous humor and iris.

BACKGROUND: Glaucoma is the primary cause of irreversible blindness worldwide associated with high intraocular pressure (IOP). Elevated intraocular pressure will affect the normal aqueous humor outflow, resulting in deformation of iris. However, the deformation ability of iris is closely related to its material properties. Meanwhile, the passive deformation of the iris aggravates the pupillary block and angle closure. The nature of the interaction mechanism of iris deformation and aqueous humor fluid flow has not been fully understood and has been somewhat a controversial issue. The purpose here was to study the effect of IOP, localization, and temperature on the flow of the aqueous humor and the deformation of iris interacted by aqueous humor fluid flow. METHODS: Based on mechanisms of aqueous physiology and fluid dynamics, 3D model of anterior chamber (AC) was constructed with the human anatomical parameters as a reference. A 3D idealized standard geometry of anterior segment of human eye was performed. Enlarge the size of the idealization geometry model 5 times to create a simulation device by using 3D printing technology. In this paper, particle image velocimetry technology is applied to measure the characteristic of fluid outflow in different inlet velocity based on the device. Numerically calculations were made by using ANSYS 14.0 Finite Element Analysis. Compare of the velocity distributions to confirm the validity of the model. The fluid structure interaction (FSI) analysis was carried out in the valid geometry model to study the aqueous flow and iris change. RESULTS: In this paper, the validity of the model is verified through computation and comparison. The results indicated that changes of gravity direction of model significantly affected the fluid dynamics parameters and the temperature distribution in anterior chamber. Increased pressure and the vertical position increase the velocity of the aqueous humor fluid flow, with the value increased of 0.015 and 0.035 mm/s. The results act on the iris showed that, gravity direction from horizontal to vertical decrease the equivalent stress in the normal IOP model, while almost invariably in the high IOP model. With the increased of the iris elasticity modulus, the equivalent strain and the total deformation of iris is decreased. The maximal value of equivalent strain of iris in high IOP model is higher than that of in normal IOP model. The maximum deformation of iris is lower in the high IOP model than in the normal IOP model. CONCLUSION: The valid model of idealization geometry of human eye could be helpful to study the relationship between localization, iris deformation and IOP. So far the FSI analysis was carried out in that idealization geometry model of anterior segment to study aqueous flow and iris change.

Experimental research on intraocular aqueous flow by PIV method.

BACKGROUND: Aqueous humor flows regularly from posterior chamber to anterior chamber, and this flow much involves intraocular pressure, the eye tissue nutrition and metabolism. PURPOSE: To visualize and measure the intraocular flow regular pattern of aqueous humor. METHOD: Intraocular flow in the vitro eyeball is driven to simulate the physiological aqueous humor flow, and the flow field is measured by Particle Image Velocimetry(PIV). Fluorescent particle solution of a certain concentration was infused into the root of Posterior Chamber(PC) of vitro rabbit eye to simulate the generation of aqueous and was drained out at a certain hydrostatic pressure from the angle of Anterior Chamber(AC) to represent the drainage of aqueous. PIV method was used to record and calculate the flow on the midsagittal plane of the eyeball. RESULTS: Velocity vector distribution in AC has been obtained, and the distribution shows symmetry feature to some extent. Fluorescent particle solution first fills the PC as it is continuously infused, then surges into AC through the pupil, flows upwards toward the central cornea, reflecting and scattering, and eventually converges along the inner cornea surface towards the outflow points at the periphery of the eyeball. Velocity values around the pupillary margin are within the range of 0.008-0.012 m/s, which are close to theoretical values of 0.0133 m/s, under the driving rate of 100 µl/min. CONCLUSIONS: Flow field of aqueous humor can be measured by PIV method, which makes it possible to study the aqueous humor dynamics by experimental method. Our study provides a basis for experimental research on aqueous humor flow; further, it possibly helps to diagnose and treat eye diseases as shear force damage of ocular tissues and destructions on corneal endothelial cells from the point of intraocular flow field.

Experimental research on the mechanical properties of porcine iris.

Quantification of the mechanical properties of the iris is necessary to assess the clinical significance of passive iris deformation, which has been suggested as a mechanism for angle closure glaucoma. The animal model simulating the total pupillary block was developed to simulate angle closure glaucoma, and experiments were performed on isolated porcine irises, deformation of the iris was captured when changing the pressure difference between the posterior and anterior chamber. A simple mechanical model was used to account for the geometry of the experiment. The relationship between the area strain (delta) and the pressure differences between the posterior and anterior chamber (P') is described as delta=b(0)+b(1)LnP'. Furthermore the radial 2D elastic mechanics parameter was calculated. The average 2D elastic mechanics parameter of porcine iris was found to be 5.3N/m in the radial direction and 24.7N/m in azimuthal direction. Experimental results provide reliable theoretical and experimental base for explanation of the blindness caused by Glaucoma.

Experimental research on the biomechanical properties of the rabbit iris.

OBJECTIVE: To qualify the mechanical properties of the iris during its passive deformation under the condition of glaucoma. MATERIAL AND METHODS: Experiments simulating the total pupillary block was performed on isolated rabbit irises to determine the passive mechanical behavior of the intact iris. RESULTS: The relationship between the area strain(delta) and the pressure of posterior chamber relative to the anterior chamber(P') was obtained: (P1) was obtained P'+b eb1 delta.