Polygonal Structures Research Articles

An autonomous laser kirigami method with low-cost real-time vision-based surface deformation feedback system

We introduce an autonomous laser kirigami technique, a novel custom manufacturing machine system which functions somewhat similar to a photocopier. This technique is capable of creating functional freeform shell structures using cutting and folding (kirigami) operations on sheet precursors. Conventional laser kirigami techniques are operated manually and rely heavily on precise calibrations. However, it is unrealistic to design and plan out the process (open loop) to realize arbitrary geometric features from a wide variety of materials. In our work, we develop and demonstrate a completely autonomous system, which is composed of a laser system, a 4-axis robotic arm, a real-time vision-based surface deformation monitoring system, and an associated control system. The laser system is based on the Lasersaur, which is a 120-Watt CO2 open-source laser cutter. The robotic arm is employed to precisely adjust the distance between a workpiece and the laser lens so that a focused and defocused laser beam can be used to cut and fold the workpiece respectively. The four-axis robotic arm provides flexibility for expanding the limits of possible shapes, compared to conventional laser machine setups where the workpiece is fixed on rigid holders. The real-time vision-based surface deformation monitoring system is composed of four low-cost cameras, an integrated AI-assisted algorithm, and the sensors (detachable planar markers) mounted on the polymer-based sheet precursors, and allows real-time monitoring of the sheet forming process with a geometric feature estimation error less than 5% and delay time around 100 ms. The developed control system manages the laser power, the laser scanning speed, the motion of the robotic arm based on the designed plan, and the close-loop feedback provided by the vision-based surface deformation monitoring system. This cyber-physical kirigami platform can operate a sequence of cutting and folding processes in order to create kirigami objects. Hence, complicated kirigami design products with various different polygonal structures can be realized by undergoing sequential designed laser cuts and bends (at any folding angles within designed geometric tolerance) using this autonomous kirigami platform.

2D Optical Waveguides Based on Hierarchical Organic Semiconductor Single Crystals

AbstractToward the evolution of integrated optoelectronic circuits, it is vital matter to realize 2D optical waveguide at micro/nanoscale. However, due to the waveguiding principle of the traditional dielectric waveguide, the transverse and longitudinal dimensions cannot be greatly reduced, thus the size of photonic apparatus is far from reaching the size level for the microelectronic device. Therefore, it is difficult to achieve a high‐level hybrid integration of integrated optical path and microelectronic circuit. However, the organic crystals with polygonal structure and hierarchical structure as the medium also can form optical waveguide by confining photons/electrons at the micro/nanoscale along different directions, and these organic microcrystals can be well applied into the ultracompact optoelectronic devices. Herein, the fabrication of organic crystals as the medium of 2D optical waveguide is briefly introduced, as well as the 2D optical waveguide phenomenon existing in these polygonal and hierarchical microcrystals. Moreover, a conclusion is drawn and expectations are expressed for the 2D optical waveguide based on organic microstructure in the near future.

Root cause analysis of a failure in a flange-pipe welded joint in a steam line in an ammonia plant: Experimental investigation and simulation assessment

This study aims to investigate the root cause of a failure in an ASTM A106 pipe-ASTM A105 flange welded joint, welded to a pump in an ammonia plant. Samples were taken from the failed joint. These joints were exposed to steam at the temperature of 148 °C and internal pressure of 7 bar. The changes in metal microstructures along the welded metal showed that root pass region consists of large grain-size structure, containing Widmanstätten, grain boundary and polygonal ferrite structures. On the other hand, the areas on the middle and upper sections of the weld mostly contained acicular ferrites. The results of hardness tests indicated that the root pass region has lower hardness compared to other areas which is due to large grain size structure in this region. In addition, simulation results showed that a rather large residual tensile stress exists at the root of the weldment. Besides, results of fractography showed that areas close to the weld root consisted of a quasi-cleavage structure. Based on the results, it can be postulated that the main reason for the failure was unsuitable welding parameters which have resulted in the formation of large grain structures with low strength.

ZIF-8 supported Sb2S3 fabrication carbon coating nanocomposite for dopamine sensor application

A ZIF-8 supported Sb2S3 fabrication carbon coating ZnS-Sb2S3 nanocomposite was synthesized with the template of zeolitic imidazolate framework (ZIF), through by the introduction of resorcinol-formaldehyde (RF) organic polymer to establish carbon layer, and by vulcanization process and metal-ion exchange reaction. The morphology and structural characteristics of carbon coating ZnS-Sb2S3 were investigated by X-ray diffraction spectroscopy, Raman spectra, X-ray photoelectron spectroscopy, Scanning electron microscopy and Transmission electron microscopy. Evidence indicated the nanocomposite has a polygonal structure with ZnS as core, Sb2S3 as inner shell, carbon layer coating as outer shell. This material was employed to prepare an electrode detected DA sensor; and its electrochemical impedance properties exhibited that carbon layer coating Sb2S3 nanoparticles can greatly improve the conductivity of nanocomposite. The proposed sensor showed some outstanding electrocatalytic performances, including a linear range from 0.2 to 3.1 μM, 3.1 to 711.1 μM, and a low detection limit of 0.6 μM and an excellent sensitivity of 458.3 and 184.6 μA mM−1 cm−2. Therefore, the carbon coating ZnS-Sb2S3 nanocomposite can be an effective electrode-modifying material that can be promisingly used in other electrochemical applications, and this method of preparing nanomaterials offer a novel perspective for electrochemical design the of other nanostructured systems.

CFD Simulation and Performance Investigation on a Novel Bionic Spider-Web-Type Flow Field for PEM Fuel Cells

The products generated by the electrochemical reaction in the PEM fuel cell (PEMFC) are mainly concentrated in the flow field on the cathode side of the bipolar plate, and the oxygen introduced on the cathode has higher requirements to improve its diffusion performance by using the flow field structure. For this reason, the optimization of the cathode flow field of the PEMFC is essential. Inspired by the structure of a spider web, this paper proposes a novel spider-web-type flow field. In this kind of flow field, the shape of a polygonal structure and the number of layers of spiral flow channels are the two most crucial variables. In order to explore the impact of these two variables on the cathode flow field, complete three-dimensional PEMFC models with different values of the two variables were established, and the models were simulated by the method of CFD. By observing the results of oxygen distribution, the water removal performance and fuel cell output performance of different schemes, the optimal scheme of the polygonal structure and layer number are determined. Compared with the traditional flow field, it is proved that the optimization scheme is desirable in improving the performance of the cathode flow field in PEMFC.

Study of structural properties and J-V voltametric cyclic of MoTe2 binary thin films: Phase transition from MoO3-TeO2 to 2H-MoTe2

The structural phase transition and ionic exchange in two-dimensional transition metals oxides have very important effect on their physical properties. The MoO3-TeO2 binary compounds can be used to improve these properties. In binary compounds, this exchange occurs easily due to the formation of an oxygen vacancy. In this paper, the MoO3 - TeO2 binary compounds thin films have been deposited by spray pyrolysis technique at Ts = 400 °C and structural phase transition from MoO3-TeO2 to 2H-MoTe2 has been investigated. The molar concentration of [MoO3 - TeO2] in initial solution was changed at molar ratios (a) MoO3 (0.05 M) - TeO2 (0.15 M), (b) MoO3 (0.1 M) -TeO2 (0.1 M) and (c) MoO3 (0.15 M) - TeO2 (0.05 M). The structural and electrochromic properties of MoO3 - TeO2 thin films have been studied before and after annealing at T = 500 °C. The X-ray diffraction results of the films showed that, before annealing, the amorphous phase and after annealing at T = 500 °C, the MoO2, Te2O5, H6TeO6 and MoTe2 phases were formed. The FE-SEM images after annealing showed that, the morphology of films including nanoparticles which are almost uniformly distributed, is polygon structures. The electrochromic results showed that higher number of particles and holes in the surface of the electrochromic layers lead to the higher charge exchange rate and then the coloration. Also, in the hysteresis curve of J-V voltametric cyclic, MoO3-TeO2 compound with molar concentration of (a) MoO3 (0.05 M) - TeO2 (0.15 M) has higher area than other compounds and the diffusion coefficient of this sample has been studied before and after annealing at T = 500 °C.

Fabrication of ZnO/CuO Hybrid Nanocomposite for Photocatalytic Degradation of Brilliant Cresyl Blue (BCB) Dye in Aqueous Solutions

Here in the present study, we report the synthesis of ZnO nanoparticles, ZnO/CuO(3%), ZnO/CuO(5%), and ZnO/CuO(10%), nanocomposites using simple precipitation method with variation of CuO content and the activities of prepared samples were investigated for degradation of Brilliant Cresyl Blue (BCB) dye under visible light conditions in aqueous solutions. The structural, morphology, optical and compositional characteristics of fabricated samples were characterized by using Fourier Transform Infra-Red (FTIR) Spectroscopy, Field Emission Scanning Electron Microscopy combine electron dispersive spectroscopy (FESEM-EDS) and UV-vis spectroscopy. FESEM images show that ZnO nanoparticles are polygon like shape structure while ZnO/CuO have polygon and sheet shape structures. XRD patterns reflect the high crystalinity and purity of samples. The optical band gap values determined from optical absorption method indicate that band gap energy decreased with increase of CuO content in ZnO. The catalytic efficiency of the ZnO/CuO hybrid nanocomposite was observed to be higher than the ZnO nanoparticles under similar reaction conditions, 97.30% of Brilliant Cresyl Blue (BCB) dye was degraded after 100 min of irradiation of visible light radiation using the ZnO/CuO(5%) hybrid nanocomposite. The higher efficiency of ZnO/CuO compare to ZnO may be due to increased surface area and decreased band gap energy. The kinetic study of the photoctalytic degradation displayed that hybrid ZnO/CuO degrdaded dye with high rate constant k (34.88x10-3 min -1) compare to ZnO (k, 7.00x10-3 min-1). The optimization of reaction conditions of photodegradation process were attained by the variation in reaction factors such as pH, dye concentration, catalyst amount, and reaction time.

Structure-aware indoor scene reconstruction via two levels of abstraction

In this paper, we propose a novel approach that reconstructs the indoor scene in a structure-aware manner and produces two meshes with different levels of abstraction. To be precise, we start from the raw triangular mesh of indoor scene and decompose it into two parts: structure and non-structure objects. On the one hand, structure objects are defined as significant permanent parts in the indoor environment such as floors, ceilings and walls. In the proposed algorithm, structure objects are abstracted by planar primitives and assembled into a polygonal structure mesh. This step produces a compact structure-aware watertight model that decreases the complexity of original mesh by three orders of magnitude. On the other hand, non-structure objects are movable objects in the indoor environment such as furniture and interior decoration. Meshes of these objects are repaired and simplified according to their relationship with respect to structure primitives. Finally, the union of all the non-structure meshes and structure mesh comprises the scene mesh. Note that structure mesh and scene mesh preserve various levels of abstraction and can be used for different applications according to user preference. Our experiments on both LIDAR and RGBD data scanned from simple to large scale indoor scenes indicate that the proposed framework generates structure-aware results while being robust and scalable. It is also compared qualitatively and quantitatively against popular mesh approximation, floorplan generation and piecewise-planar surface reconstruction methods to demonstrate its performance.

Anti-hepatitis B virus activity and hepatoprotective effect of des(rhamnosyl) verbascoside from Lindernia ruellioides in vitro.

Although clinically approved hepatitis B virus (HBV) polymerase inhibitors (lamivudine-3TC, entecavir, etc.) serve as effective therapeutics, the virus can easily generate resistance to them. Therefore, the treatment of HBV infection remains a public health problem. Numerous studies have shown that natural products have prospective anti-HBV activity. The purpose of this study was to isolate and extract des(rhamnosyl) verbascoside from Lindernia ruellioides (Colsm.) Pennell and explore its anti-HBV and hepatoprotective effects. Anti-HBV activity was evaluated in HepG2.2.15 cells, a human hepatocellular carcinoma cell line with HBV-stable infection, and its protective effect was evaluated in HL-7702 cells, a normal human liver cell line. HepG2.2.15 cells maintained normal growth morphology within the selected concentration range of des(rhamnosyl) verbascoside. It also inhibited the expression of HBV antigens and HBV DNA in a dose- and time-dependent manner in vitro. Further, western blot experiments showed that it could downregulate HBV X protein (HBx) expression in a dose-dependent manner. In the H2 O2 -induced hepatocyte injury model, the cell-survival rate of the HL-7702 cells with the highest drug dose reached 85.25%, which was significantly improved compared with that of the model group. Most of the cells returned to normal morphology, showing polygonal or fusiform structures. Thus, it may be stated that des(rhamnosyl) verbascoside exhibits anti-HBV activity and hepatoprotective effects in vitro and may exert an anti-HBV effect via antigen inhibition, HBV DNA secretion, and HBx protein expression.

DNA Origami Penetration in Cell Spheroid Tissue Models is Enhanced by Wireframe Design.

As DNA origami applications in biomedicine are expanding, more knowledge is needed to assess these structures' interaction with biological systems. Here, uptake and penetration in cell and cell spheroid tissue models (CSTMs) are studied to elucidate whether differences in internal structure can be a factor in the efficacy of DNA-origami-based delivery. Two structures bearing largely similar features in terms of both geometry and molecular weight, but with different internal designs-being either compact, lattice-based origami or following an open, wireframe design-are designed. In CSTMs, wireframe rods are able to penetrate deeper than close-packed rods. Moreover, doxorubicin-loaded wireframe rods show a higher cytotoxicity in CSTMs. These results can be explained by differences in structural mechanics, local deformability, local material density, and accessibility to cell receptors between these two DNA origami design paradigms. In particular, it is suggested that the main reason for the difference in penetration dynamic arises from differences in interaction with scavenger receptors where lattice-based structures appear to be internalized to a higher degree than polygonal structures of the same size and shape. It is thus argued that the choice of structural design method constitutes a crucial parameter for the application of DNA origami in drug delivery.

Self-organized optimal packing of kinesin-5-driven microtubule asters scales with cell size.

Radial microtubule (MT) arrays or asters determine cell geometry in animal cells. Multiple asters interacting with motors, such as those in syncytia, form intracellular patterns, but the mechanical principles behind this are not clear. Here, we report that oocytes of the marine ascidian Phallusia mammillata treated with the drug BI-D1870 spontaneously form cytoplasmic MT asters, or cytasters. These asters form steady state segregation patterns in a shell just under the membrane. Cytaster centers tessellate the oocyte cytoplasm, that is divide it into polygonal structures, dominated by hexagons, in a kinesin-5-dependent manner, while inter-aster MTs form 'mini-spindles'. A computational model of multiple asters interacting with kinesin-5 can reproduce both tessellation patterns and mini-spindles in a manner specific to the number of MTs per aster, MT lengths and kinesin-5 density. Simulations predict that the hexagonal tessellation patterns scale with increasing cell size, when the packing fraction of asters in cells is ∼1.6. This self-organized in vivo tessellation by cytasters is comparable to the 'circle packing problem', suggesting that there is an intrinsic mechanical pattern-forming module that is potentially relevant to understanding the role of collective mechanics of cytoskeletal elements in embryogenesis. This article has an associated First Person interview with the first author of the paper.

A Dense Multilevel 30-Sided Space Vector Generation Using a Single DC Link for an Induction Motor Drive

Modulation using a higher sided polygonal space vector structure (SVS) is an elegant method to increase the linear modulation range and to eliminate the undesired lower order harmonics from motor phase voltage. This article presents the generation of a dense 15-concentric 30-sided multilevel SVS using a single dc-link for an open end induction motor (OEIM) drive. The proposed scheme eliminates lower order harmonics till 25th order from motor phase voltage throughout the modulation range. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$dv/dt$</tex-math></inline-formula> stress in the phase voltage applied to the motor will also be highly reduced owing to the multilevel structure. The pulsewidth modulation scheme employed utilizes the denseness of SVS and avoids iterative searches to find the triangle, which encompasses the tip of reference voltage vector, which are typical in multilevel polygonal SVS. The topology consists of an active dc-link fed three-level primary inverter and a capacitor fed five-level secondary inverter connected to either end of an OEIM. The primary inverter acts as the active power supplier for the drive and the secondary inverter filters out the undesirable lower order harmonics from motor phase voltage. The proposed scheme is experientially validated and the results are included in this article.

Magnetic Anomalies Caused by 2D Polygonal Structures With Uniform Arbitrary Polarization: New Insights From Analytical/Numerical Comparison Among Available Algorithm Formulations

AbstractSince the '60s of the last century, the calculation of the magnetic anomalies caused by 2D uniformly polarized bodies with polygonal cross‐section has been mainly performed using the popular algorithm of Talwani and Heirtzler (1962, 1964). Recently, Kravchinsky et al. (2019, https://doi.org/10.1029/2019GL082767) claimed errors in the above algorithm formulation, proposing new corrective formulas and questioning the effectiveness of almost 60 years of magnetic calculations. Here we show that the two approaches are equivalent and Kravchinsky et al.'s formulas simply represent an algebraic variant of those of Talwani and Heirtzler. Moreover, we analyze a large amount of random magnetic scenarios, involving both changing‐shape polygons and a realistic geological model, showing a complete agreement among the magnetic responses of the two discussed algorithms and the one proposed by Won and Bevis (1987, https://doi.org/10.1190/1.1442298). We release the source code of the algorithms in Julia and Python languages.

Harmonics mitigation approach by using pulse‐doubling circuit in the AC–DC rectifier

SummaryIn this research, a novel pulse‐doubling circuit (PDC) is employed to upgrade the 28‐pulse rectifier to the efficient 56‐pulse rectifier. The main objective of this research is to reduce the power kVA rating. In the autotransformer with a 14‐phase polygon structure, the kVA rating is approximately 39.5% of the load power. Since the pulse‐doubling method is utilized, the rectifier with 56 pulses has benefited from a simpler structure. With a comparison to the other rectifiers, the harmonic mitigation is the clearest feature of the proposed rectifier. According to the experimental and theoretical results, in the proposed rectifier with 56 pulses, the input current THD is less than 3%. Finally, the volume and cost of the proposed rectifier with 56 pulses show a notable reduction. In other words, the proposed rectifier is an economical choice for most sectors of the industry.

The recent advances in C60 micro/nanostructures and their optoelectronic applications

Due to the unique physical and chemical properties of fullerene (C60) molecules, micro/nanostructures of fullerene molecules have exhibited great potential in the field of optoelectronics. The growth process of C60 micro/nanostructures can be controlled fabricated through different preparation approaches, such as liquid-liquid interface precipitation, template method. When adjusting the solvent, temperature and concentration, the morphology and the size of the C60 micro/nanostructures will be changed. Therefore, one-dimensional structure, polygonal structure, nanoflower structure, and mesh structure can be obtained. Due to the low recombination energy and high mobility of C60, it also has good optoelectronic properties, and C60 micro/nanostructures with different morphologies will also affect its optoelectronic properties. In this review, we mainly summarize the C60 micro/nanostructures prepared by different methods and their applications in the field of optoelectronics. In the end, the perspectives for the future development are given, hopefully to provide useful guidance for the future research on C60 micro/nanostructures.

Cell-free oxidized hemoglobin drives reactive oxygen species production and pro-inflammation in an immature primary rat mixed glial cell culture

BackgroundGerminal matrix intraventricular hemorrhage (GM-IVH) is associated with deposition of redox active cell-free hemoglobin (Hb), derived from hemorrhagic cerebrospinal fluid (CSF), in the cerebrum and cerebellum. In a recent study, using a preterm rabbit pup model of IVH, intraventricularly administered haptoglobin (Hp), a cell-free Hb scavenger, partially reversed the damaging effects observed following IVH. Together, this suggests that cell-free Hb is central in the pathophysiology of the injury to the immature brain following GM-IVH. An increased understanding of the causal pathways and metabolites involved in eliciting the damaging response following hemorrhage is essential for the continued development and implementation of neuroprotective treatments of GM-IVH in preterm infant.MethodsWe exposed immature primary rat mixed glial cells to hemorrhagic CSF obtained from preterm human infants with IVH (containing a mixture of Hb-metabolites) or to a range of pure Hb-metabolites, incl. oxidized Hb (mainly metHb with iron in Fe3+), oxyHb (mainly Fe2+), or low equivalents of heme, with or without co-administration with human Hp (a mixture of isotype 2-2/2-1). Following exposure, cellular response, reactive oxygen species (ROS) generation, secretion and expression of pro-inflammatory cytokines and oxidative markers were evaluated.ResultsExposure of the glial cells to hemorrhagic CSF as well as oxidized Hb, but not oxyHb, resulted in a significantly increased rate of ROS production that positively correlated with the rate of production of pro-inflammatory and oxidative markers. Congruently, exposure to oxidized Hb caused a disintegration of the polygonal cytoskeletal structure of the glial cells in addition to upregulation of F-actin proteins in microglial cells. Co-administration of Hp partially reversed the damaging response of hemorrhagic CSF and oxidized Hb.ConclusionExposure of mixed glial cells to oxidized Hb initiates a pro-inflammatory and oxidative response with cytoskeletal disintegration. Early administration of Hp, aiming to minimize the spontaneous autoxidation of cell-free oxyHb and liberation of heme, may provide a therapeutic benefit in preterm infant with GM-IVH.

Reliability for consecutive-[formula omitted]-out-of-[formula omitted]: F systems with shared components between adjacent subsystems

Consecutive-k systems have well known for outstanding developments and extensive applications. In this paper, we propose consecutive-k-out-of-n: F systems with shared components between adjacent subsystems which extend the consecutive-k-out-of-n: F linear and circular models and the consecutive-kr-out-of-nr: F linear zigzag structure and circular polygon structure. They are referred to as an extension of linear zigzag structure and an extension of circular polygon structure respectively. The idea of computation for reliability is to cut the system into m subsystems and to get the reliability of every subsystem, then to obtain the system reliability in terms of reliabilities of all subsystems, the probability of occurrence of each event and the system structure. Based on this view, we obtain the reliability for the above two structures by combining the sum of disjoint products with finite Markov chain imbedding approach (FMCIA). A numerical example demonstrates the efficiency of the proposed method for our new models.

Symmetry Analysis of Oriental Polygonal Pagodas Using 3D Point Clouds for Cultural Heritage.

Ancient pagodas are usually parts of hot tourist spots in many oriental countries due to their unique historical backgrounds. They are usually polygonal structures comprised by multiple floors, which are separated by eaves. In this paper, we propose a new method to investigate both the rotational and reflectional symmetry of such polygonal pagodas through developing novel geometric models to fit to the 3D point clouds obtained from photogrammetric reconstruction. The geometric model consists of multiple polygonal pyramid/prism models but has a common central axis. The method was verified by four datasets collected by an unmanned aerial vehicle (UAV) and a hand-held digital camera. The results indicate that the models fit accurately to the pagodas’ point clouds. The symmetry was realized by rotating and reflecting the pagodas’ point clouds after a complete leveling of the point cloud was achieved using the estimated central axes. The results show that there are RMSEs of 5.04 cm and 5.20 cm deviated from the perfect (theoretical) rotational and reflectional symmetries, respectively. This concludes that the examined pagodas are highly symmetric, both rotationally and reflectionally. The concept presented in the paper not only work for polygonal pagodas, but it can also be readily transformed and implemented for other applications for other pagoda-like objects such as transmission towers.

A Very High Resolution 30-Sided Space Vector Generation From a Single DC-Link for Induction Motor Drives

A voltage source inverter generating a polygonal voltage space vector structure (SVS) having 117- concentric 30-sided polygons of different radii are proposed. Modulation using a 30-sided SVS eliminates lower order harmonics till 25th order from motor phase voltage. The proposed scheme combines the advantages of a 30-sided SVS with that of a multilevel inverter. The topology consists of two cascaded five-level inverters feeding from either end of the open-end induction motor stator windings. One of the cascaded five-level inverter is connected to an active dc source and delivers the required active power for the scheme, while the other is capacitor fed and acts as a switched capacitive filter. In this article, nonaligned 30-sided polygons, i.e., regular 30-sided polygons that are not symmetric with respect to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\alpha$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\beta$</tex-math></inline-formula> axis are also considered for inverter operation. The harmonic analysis of such nonaligned 30-sided polygons is investigated in this article. Nearest level switching is employed throughout the modulation range, enabling further reduction of switching loss in the system. Extensive hardware experimentations are carried out to validate the proposed scheme and the results are included in the article.

Self assembly of model polymers into biological random networks

The properties of biological networks, such as those found in the ocular lens capsule, are difficult to study without simplified models. Model polymers are developed, inspired by “worm-like” curve models, that are shown to spontaneously self assemble to form networks similar to those observed experimentally in biological systems. These highly simplified coarse-grained models allow the self assembly process to be studied on near-realistic time-scales. Metrics are developed (using a polygon-based framework) which are useful for describing simulated networks and can also be applied to images of real networks. These metrics are used to show the range of control that the computational polymer model has over the networks, including the polygon structure and short range order. The structure of the simulated networks are compared to previous simulation work and microscope images of real networks. The network structure is shown to be a function of the interaction strengths, cooling rates and external pressure. In addition, “pre-tangled” network structures are introduced and shown to significantly influence the subsequent network structure. The network structures obtained fit into a region of the network landscape effectively inaccessible to random (entropically-driven) networks but which are occupied by experimentally-derived configurations.