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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. [ABSTRACT FROM AUTHOR]

• Frost stochastic damage meso -equivalence method was established. • The meso -equivalence calculation model was established. • Reliability of the FSDMEM was verified by comparing. • Meso-equivalence calculation model is more efficient than meso -calculation model. • Stiffness of some RC columns with FTCs is only half that of un-FTC RC columns. • Bearing capacity of RC columns with FTCs exhibits a significant decline. In cold regions, frost resistance is a critical factor affecting the durability of reinforced concrete (RC) structures. In light of this, the frost stochastic damage meso -equivalence method (FSDMEM) was established based on the frost stochastic damage (FSD) model, which considers the frost stochastic damage and is combined with the random aggregate model (RAM). According to the FSDMEM, the meso -equivalence calculation model was proposed and its reliability can be verified by comparing test and calculation results of concrete specimens after freeze–thaw cycles (FTCs) and RC columns after FTCs. The results show that the maximum deviation between calculation and test results of mechanical property degradation of concrete specimens was only 5.71%, which confirms the accuracy of the FSDMEM. The calculation results of both meso -calculation and meso -equivalence calculation models are in good agreement with test results, and the meso -equivalence calculation model is more efficient than the meso -calculation model, with a considerably smaller number of equivalent elements, making it more suitable for the simulation of large-scale RC structures. The stiffness of some RC columns with FTCs is only half that of un-FTC RC columns, and the bearing capacity of RC columns exhibits a significant decline under loading due to the FTCs deterioration of concrete. The meso -equivalence calculation results the stiffness and bearing capacity of RC columns are consistent with the test results, with a small deviation, verifying the accuracy of the FSDMEM. [ABSTRACT FROM AUTHOR]

Heavy metals migrate throughout the ecosystem with water cycling, posing a significant threat to food safety, environmental safety, and human health. Atomic spectrometry has many advantages, such as rapid, real-time, in situ, and high resolution, and has great application potential in heavy metal isotope analysis in environmental monitoring, biomedicine, and nuclear fuels. The present article reviews the progress of atomic spectrometry for heavy metal isotope analysis, classified into linear spectroscopic methods (atomic emission, atomic absorption, and laser-excited atomic fluorescence spectrometry) and non-linear spectroscopic methods (saturated absorption spectrometry, four-wave mixing spectrometry, and Doppler-free two-photon spectrometry). It mainly focuses on the principles and applications in analyzing the heavy metal isotopic concentration and energy level structure. It also summarizes the fundamentals of isotope analysis according to the considerations of choosing spectroscopic methods for isotope analysis, which include the isotope shifts of a set of heavy metal transitions, the characteristics of atomic spectrometry, and related instrumentation. Finally, it discusses the advantages and disadvantages compared with mass spectrometry and an outlook of challenges and research opportunities within the field. [Display omitted] • Atomic spectrometry offers unique advantages due to its simple analytical flow, simple pretreatment process, low cost, etc. • Six linear and non-linear spectroscopic methods are reviewed, including their principles and applications for heavy metal isotope analysis. • Isotope shifts of a set of commonly used heavy metal transitions are enumerated. • The Characteristics of atomic spectrometry are summarized based on the considerations of choosing spectroscopic methods for isotope analysis. [ABSTRACT FROM AUTHOR]

To maximize a firm's profit over a finite planning horizon, we develop a dynamic optimization model by considering loss aversion when making pricing and inventory decisions. We estimate customer demand through a choice model, which incorporates reference price, utility function and customer loss aversion. Our model forms the core of the expert system for decision support. Through a sequence of Bellman equations, we find that the firm's profit is a concave function of price and inventory, and we solve the model optimally. The profit is positively correlated with the reference price, and the price and inventory decisions are non-monotonic functions of loss aversion intensity. Our results shed new light on pricing and inventory management with customer behavior in a multi-period system. Through various theorem developments, we are able to identify the optimal inventory level and the corresponding price. Numerical examples are provided to illustrate and validate the model and to derive managerial insights. To show the potential significance, we demonstrate how a dynamic programming model yields good results with customer loss aversion under realistic customer behavior assumptions. Our system can improve the efficiency of decision making and provide better customer service. [ABSTRACT FROM AUTHOR]

Abstract: A nanocomposite of needle-like MnO2 nanowires arrays-graphene (NMNAG) is synthesized by in-situ growth of MnO2 nanowires on the surface of graphene nanosheets (GNS), resulting in a sandwich nanoarchitecture hybrid. The preparation is a simple redox reaction between potassium permanganate (KMnO4) and GNS, which is facile to produce in large scale at low cost. The nanocomposite exhibits high-capacitance performance (276Fg−1 at 0.5Ag−1), excellent rate capability (62.7% capacity retention at 60Ag−1), stable cycleability (no degradation after 1200 cycles) and a maximum power density of 21.6kWkg−1. [Copyright &y& Elsevier]

A nanocomposite of graphene/MnO nanoplatelets was prepared by one-step chemistry route at room temperature. The microstructure was characterized by X-ray diffraction, N absorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Both TEM and SEM images show that MnO nanoplatelets are homogeneously distributed on the graphene nanosheets. The electrochemical properties were tested by cyclic voltammetry, galvanostatic charge-discharge experiments. The nanocomposite exhibited high lithium capacity (905 mAh g at 100 mA g). The superior lithium storage capability can be attributed to the 'open' structure: the large effective surface area and short diffusion paths. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, an extended (3+1)-dimensional nonlinear Schrödinger equation with cubic-quintic nonlinearity term is studied. By using the ansatz method, some exact solutions of this equation are obtained, which include solitons solutions, elliptic function solutions, and periodic function solutions. The relations between these solutions and their coefficients are obtained. [ABSTRACT FROM AUTHOR]

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

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. [ABSTRACT FROM AUTHOR]

Abstract: 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 (δ) and the pressure differences between the posterior and anterior chamber (P′) is described as δ = 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. [Copyright &y& Elsevier]