Key Morphological Parameters Research Articles

Morphological Estimation of Cellularity on Neo-Adjuvant Treated Breast Cancer Histological Images

This paper describes a methodology that extracts key morphological features from histological breast cancer images in order to automatically assess Tumour Cellularity (TC) in Neo-Adjuvant treatment (NAT) patients. The response to NAT gives information on therapy efficacy and it is measured by the residual cancer burden index, which is composed of two metrics: TC and the assessment of lymph nodes. The data consist of whole slide images (WSIs) of breast tissue stained with Hematoxylin and Eosin (H&E) released in the 2019 SPIE Breast Challenge. The methodology proposed is based on traditional computer vision methods (K-means, watershed segmentation, Otsu’s binarisation, and morphological operations), implementing colour separation, segmentation, and feature extraction. Correlation between morphological features and the residual TC after a NAT treatment was examined. Linear regression and statistical methods were used and twenty-two key morphological parameters from the nuclei, epithelial region, and the full image were extracted. Subsequently, an automated TC assessment that was based on Machine Learning (ML) algorithms was implemented and trained with only selected key parameters. The methodology was validated with the score assigned by two pathologists through the intra-class correlation coefficient (ICC). The selection of key morphological parameters improved the results reported over other ML methodologies and it was very close to deep learning methodologies. These results are encouraging, as a traditionally-trained ML algorithm can be useful when limited training data are available preventing the use of deep learning approaches.

The Effect of Morphology on Solar Potential of High-Density Residential Area: A Case Study of Shanghai

This study explores the relationship between the morphology and solar potential of high-density areas in the subtropics high density city known as Shanghai. 1260 parametric scenarios were modeled and their solar irradiation potentials were simulated via a customized workflow. In addition to the five well-known morphological parameters, this study proposed two innovative morphological parameters SSU600 and SSU400, which captured the solar receiving properties of the building envelopes and could be easily calculated based on the meteorological data. For analytical purposes, the previously morphological parameters were considered as independent variables, whereas the new solar performance indicators SRU600 and SRU400 were both examined as dependent variables. The correlation analysis results suggested that the new morphological parameters displayed a strong linear correlation with the corresponding solar performance indicators, surpassing all the other morphological parameters. Two prediction models with respect to SRU600 and SRU400 were developed by multiple linear regressions using a stepwise method and their validity was verified by real residential cases. The findings provide key morphological parameters and rapid calculation tools for establishing solar energy friendly urban planning and design.

Assessing activated sludge morphology and oxygen transfer performance using image analysis

The morphology of the microbial communities can have dramatic impacts on not only the treatment performance, but also the energy use performance of an activated sludge process. In this research, we developed and calibrated an image analysis technique to determine key morphological parameters such as the floc diameter and the specific filament length (SFL) and discovered that the SFL has significant impacts on sludge floc size, the specific extracellular polymeric substances production, the settleability, mixed liquor viscosity, and oxygen transfer efficiency. When the SFL increased from 2.5 × 109 μm g−1 to 6.0 × 1010 μm g−1, the apparent viscosity normalized by the mixed liquor suspended solids concentration increased by 67%, and the oxygen transfer efficiency decreased by 29%. A long solids retention time (SRT) of 40 day reduced SFL, improved sludge settling performance, and improved oxygen transfer efficiency as compared to shorter SRTs of 10 and 20 day. The findings underscore the need to assess microbial morphology when quantifying the treatment performance and energy performance of activated sludge processes.

Investigating the effects of pore types on the pore geometry, topology and electrical resistivity in fractured and vuggy samples using pore-scale models

ABSTRACTThe interpretation of electrical resistivity for assessing the saturation in rocks with complicated pore structures and various pore types requires the intrinsic parameters quantifying pore structures incorporated in modified resistivity models. Therefore, the objectives are to investigate pore types effect on the pore morphology and electrical resistivity and to determine the key pore morphological parameters for each pore type. The maximal ball method was applied to extract the pore networks of the reconstructed pore-scale models using a process-based method, and the pore morphology was characterized using a pore-network analysis and a random walk simulation. The resistivity was simulated using a finite element method. The key parameters determined by the Morris screening method for the fractured, isolated and connected vuggy models were the Euler number, the cross-sectional pore-to-throat area ratio (PTAR) and the pore radius, respectively. The qualitative relationships between the Euler number, the PTAR and the porosity exponent for the fractured and vuggy models were determined and validated using three Coquinas carbonates. This investigation will help to elucidate the variations of the porosity exponent and to further derive a new electrical resistivity model that correlates the pore morphology to the resistivity in fractured and vuggy carbonate reservoirs.

Multiscale prediction of acoustic properties for glass wools: Computational study and experimental validation.

This work is concerned with the multiscale prediction of the transport and sound absorption properties associated with industrial glass wool samples. In the first step, an experimental characterization is performed on various products using optical granulometry and porosity measurements. A morphological analysis, based on scanning electron imaging, is further conducted to identify the probability density functions associated with the fiber angular orientation. The key morphological characterization parameters of the microstructure, which serve as input parameters of the model, include the porosity, the weighted volume diameter accounting for both lengths and diameters of the analyzed fibers (and therefore the specific surface area of the random fibrous material), and the preferred out-of-plane fiber orientation generated by the manufacturing process. A computational framework is subsequently proposed and allows for the reconstruction of an equivalent fibrous network. A fully stochastic microstructural model, parameterized by the probability laws inferred from the database, is also proposed herein. Multiscale simulations are carried out to estimate transport properties and sound absorption. With no adjustable parameter, the results accounting for ten different samples obtained with various processing parameters are finally compared with the experimental data and used to assess the relevance of the reconstruction procedures and the multiscale computations.

Physiological basis of inter-population, inter-familiar and intra-familiar differences in growth rate in the green-lipped mussel Perna canaliculus

In New Zealand, three quarters (by value) of national aquaculture exports are based on the production of an endemic species, the green-lipped mussel, Perna canaliculus, yet there remains a paucity of information describing its underpinning biology. The majority of seed stock is still derived from wild capture from two main geographic locations, however commercial hatchery production has just begun. An established selective breeding programme, now in its 7th generation, has created family lines selected for desirable production traits, including growth rate. The current study therefore used animals derived from selectively bred lines, as well as animals produced in the hatchery from the two geographically distant populations used for commercial spat-catching, which are observed to have differences in growth rates, to explore the key energetic and morphological parameters that may determine fast and slow growth and growth efficiency. Metabolic rates, clearance and assimilation parameters, and morphological characteristics were established for mussels from 3 distinct levels of relatedness; comparing populations, full sib families (selected a priori for fast or slow growth rate), and inter-individual differences between siblings within families displaying heterogeneous growth rates.Scaling parameters were also determined for metabolic rate, clearance rate, and gill-surface area in the two wild populations of mussels, for comparison of the allometry of the populations, and for size standardization of data. No significant inter-population differences were found in the scaling exponent for any of the parameters, indicating that the size-dependency of physiological rates was effectively the same for mussels from the different geographic areas. However, in contrast, significantly different mass-specific clearance rates were seen in mussels from the two different populations, indicating enhanced energy balances for mussels derived from the Golden Bay population. In the inter- and intra-family experiments, significant differences were found between fast-growing and slow-growing mussels both in terms of anatomy (condition index and relative size of the digestive gland), and in physiological traits such as clearance rate, routine metabolic rate, scope for growth, growth efficiency and metabolic costs of feeding and growth. These results point towards a relatively higher food processing capacity in the gut of faster-growing mussels, and a generally higher metabolic cost of feeding and growth in slower growing mussels. Overall these results reveal the strength of the genetic factors in determining inter-individual variations in physiological performance affecting growth potential, and reinforce the notion that selection of breeding stock both with regard to origin or family provides considerable scope for improvement in mussel production.

Quantifying the kinetics and morphological changes of the fusion of spheroid building blocks

Tissue fusion, whereby two or more spheroids coalesce, is a process that is fundamental to biofabrication. We have designed a quantitative, high-throughput platform to investigate the fusion of multicellular spheroids using agarose micro-molds. Spheroids of primary human chondrocytes (HCH) or human breast cancer cells (MCF-7) were self-assembled for 24 h and then brought together to form an array comprised of two spheroids (one doublet) per well. To quantify spheroid fusogenicity, we developed two assays: (1) an initial tack assay, defined as the minimum amount of time for two spheroids to form a mechanically stable tissue complex or doublet, and (2) a fusion assay, in which we defined and tracked key morphological parameters of the doublets as a function of time using wide-field fluorescence microscopy over a 24 h time-lapse. The initial tack of spheroid fusion was measured by inverting the micro-molds and centrifuging doublets at various time points to assess their connectedness. We found that the initial tack between two spheroids forms rapidly, with the majority of doublets remaining intact after centrifugation following just 30 min of fusion. Over the course of 24 h of fusion, several morphological changes occurred, which were quantified using a custom image analysis pipeline. End-to-end doublet lengths decreased over time, doublet widths decreased for chondrocytes and increased for MCF-7, contact lengths increased over time, and chondrocyte doublets exhibited higher intersphere angles at the end of fusion. We also assessed fusion by measuring the fluorescence intensity at the plane of fusion, which increased over time for both cell types. Interestingly, we observed that doublets moved and rotated in the micro-wells during fusion and this rotation was inhibited by ROCK inhibitor Y-27632 and myosin II inhibitor blebbistatin. Understanding and optimizing tissue fusion is essential for creating larger tissues, organs, or other structures using individual microtissues as building parts.

Sound absorption coefficient optimization of gradient sintered metal fiber felts

An optimization method for sound absorption of gradient (multi-layered) sintered metal fiber felts is presented. The theoretical model based on dynamic flow resistivity is selected to calculate the sound absorption coefficient of the sintered metal fiber felts since it only requires three key morphological parameters: fiber diameter, porosity and layer thickness. The model predictions agree well with experimental measurements. Objective functions and constraint conditions are then set up to optimize separately the distribution of porosity, fiber diameter, and simultaneous porosity and fiber diameter in the metal fiber. The optimization problem for either a sole frequency or a pre-specified frequency range is solved using a genetic algorithm method. Acoustic performance comparison between optimized and non-optimized metal fibers is presented to confirm the effectiveness of the optimization method. Gradient sintered metal fiber felts hold great potential for noise control applications particularly when stringent restriction is placed on the total volume and/or weight of sound absorbing material allowed to use.

Flapping wing aerodynamics: from insects to vertebrates.

More than a million insects and approximately 11,000 vertebrates utilize flapping wings to fly. However, flapping flight has only been studied in a few of these species, so many challenges remain in understanding this form of locomotion. Five key aerodynamic mechanisms have been identified for insect flight. Among these is the leading edge vortex, which is a convergent solution to avoid stall for insects, bats and birds. The roles of the other mechanisms - added mass, clap and fling, rotational circulation and wing-wake interactions - have not yet been thoroughly studied in the context of vertebrate flight. Further challenges to understanding bat and bird flight are posed by the complex, dynamic wing morphologies of these species and the more turbulent airflow generated by their wings compared with that observed during insect flight. Nevertheless, three dimensionless numbers that combine key flow, morphological and kinematic parameters - the Reynolds number, Rossby number and advance ratio - govern flapping wing aerodynamics for both insects and vertebrates. These numbers can thus be used to organize an integrative framework for studying and comparing animal flapping flight. Here, we provide a roadmap for developing such a framework, highlighting the aerodynamic mechanisms that remain to be quantified and compared across species. Ultimately, incorporating complex flight maneuvers, environmental effects and developmental stages into this framework will also be essential to advancing our understanding of the biomechanics, movement ecology and evolution of animal flight.

Modeling the structure–property relations in pillar-structured organic donor/acceptor solar cells

Recently, organic solar cells with ordered morphologies in the form of vertical, interpenetrating donor- and acceptor-pillars have been demonstrated with various fabrication techniques. In order to find the optimal shape and size of these pillar structures, the conventional computational method requires simulating and comparing across different pillar designs; this may be time consuming since the pillar designs could have a large number of variations. In this paper, we establish a theoretical and computational framework that allows for efficient optimization of pillar-type morphologies. We first capture the effects of two key morphological parameters – the specific donor/acceptor interfacial area and the donor/acceptor volume ratio – with closed-form structure–property relations. We then illustrate through three-dimensional device modeling that the photovoltaic behavior of these pillar-structured cells is essentially determined by these two morphological parameters. The cross-sectional pattern of the pillar structures, on the other hand, has no major influence on the cell performance. Finally, we demonstrate a fast procedure to generate a power-density map that can aid in designing the optimal pillar structures.

Dynamics of filopodium-like protrusion and endothelial cellular motility on one-dimensional extracellular matrix fibrils.

Endothelial filopodia play key roles in guiding the tubular sprouting during angiogenesis. However, their dynamic morphological characteristics, with the associated implications in cell motility, have been subjected to limited investigations. In this work, the interaction between endothelial cells and extracellular matrix fibrils was recapitulated in vitro, where a specific focus was paid to derive the key morphological parameters to define the dynamics of filopodium-like protrusion during cell motility. Based on one-dimensional gelatin fibrils patterned by near-field electrospinning (NFES), we study the response of endothelial cells (EA.hy926) under normal culture or ROCK inhibition. It is shown that the behaviour of temporal protrusion length versus cell motility can be divided into distinct modes. Persistent migration was found to be one of the modes which permitted cell displacement for over 300 µm at a speed of approximately 1 µm min(-1). ROCK inhibition resulted in abnormally long protrusions and diminished the persistent migration, but dramatically increased the speeds of protrusion extension and retraction. Finally, we also report the breakage of protrusion during cell motility, and examine its phenotypic behaviours.

Influence of morphologies and pseudocapacitive contributions for charge storage in V2O5 micro/nano-structures

Three pure V2O5 micro/nano-structures including rods, hierarchical wires and porous tubes are synthesized via a chemical vapor deposition process by adjusting the oxidation temperature. Their surface-to-volume ratio increases significantly because of particle size decrease, pore quantity increase and hollow structure formation. Lithium-ion storage investigation in aqueous electrolyte indicates that the enlargement of surface area can suppress irreversible phase transition and lead to significant improvement of cycling stability, storage capacity and electrochemical kinetics. Furthermore, scan-rate dependence cyclic voltammetry analysis demonstrates that both pseudocapacitive and bulk Li+ storage are within these V2O5 electrodes and the relative contributions of them depend strongly on the scan rate. In porous V2O5 micro/nano-tubes, the surface pseudocapacitive storage dominates the total storage capacity at scan rates above 0.06Vs−1, whereas the bulk Li+ storage is the domination effect for V2O5 micro/nano-rods at the scan rate ranging from 0.02 to 0.3Vs−1. At the special scan rate, the maximum and minimum capacity is observed in V2O5 porous micro/nano-tubes and micro/nano-rods, respectively. These studies should be useful for elucidating the morphological effects on Li-ion storage for V2O5-based electrodes. By varying key morphological parameters, the pseudocapacitive properties of V2O5 micro/nano-structure electrodes are expected to be affected.

Does microcalcification increase the risk of rupture?

Rupture of atherosclerotic plaque, which is related to maximal stress conditions in the plaque among others, is a major cause of mortality. More careful examination of stress distributions in atherosclerotic plaques reports that it could be due to local stress behaviors at critical sites caused by cap thinning, inflammation, macroscopic heterogeneity, and recently, the presence of microcalcifications. However, the role of microcalcifications is not yet fully understood, and most finite element models of blood vessels with atheroma plaque ignore the heterogeneity of the plaque constituents at the microscale. The goal of this work is to investigate the effect of microcalcifications on the stress field of an atheroma plaque vessel section. This is achieved by performing a parametric finite element study, assuming a plane strain hypothesis, of a coronary artery section with eccentric atheroma plaque and one microcalcification incorporated. The geometrical parameters used to define and design the idealized coronary plaque anatomy and the microcalcification were the fibrous cap thickness and the microcalcification ratio, angle and eccentricity. We could conclude that microcalcifications should be considered in the modeling of this kind of problems since they cause a significant alteration of the vulnerable risk by increasing the maximum maximal principal stress up to 32%, although this increase of stress is not uniform (12% on average). The obtained results show that the fibrous cap thickness, the microcalcification ratio and the microcalcification eccentricity, in combination with the microcalcification angle, appear to be the key morphological parameters that play a determinant role in the maximal principal stress and accordingly in the rupture risk of the plaque.

Biomechanics of Larval Morphology Affect Swimming: Insights from the Sand Dollars Dendraster excentricus

Most planktonic larvae of marine invertebrates are denser than sea water, and rely on swimming to locate food, navigate advective currents, and avoid predators. Therefore, swimming behaviors play important roles in larval survival and dispersal. Larval bodies are often complex and highly variable across developmental stages and environmental conditions. These complex morphologies reflect compromises among multiple evolutionary pressures, including maintaining the ability to swim. Here, I highlight metrics of swimming performance, their relationships with morphology, and the roles of behavior in modulating larval swimming within biomechanical limits. Sand dollars have a representative larval morphology using long ciliated projections for swimming and feeding. Observed larval sand dollars fell within a narrow range of key morphological parameters that maximized their abilities to maintain directed upward movement over the most diverse flow fields, outperforming hypothetical alternatives in a numerical model. Ontogenetic changes in larval morphology also led to different vertical movements in simulated flow fields, implying stage-dependent vertical distributions and lateral transport. These model outcomes suggest a tight coupling between larval morphology and swimming. Environmental stressors, such as changes in temperature and pH, can therefore affect larval swimming through short-term behavioral adjustments and long-term changes in morphology. Larval sand dollars reared under elevated pCO(2) conditions had significantly different morphology, but not swimming speeds or trajectories. Geometric morphometric analysis showed a pH-dependent, size-mediated change in shape, suggesting a coordinated morphological adjustment to maintain swimming performance under acidified conditions. Quantification of the biomechanics and behavioral aspects of swimming improves predictions of larval survival and dispersal under present-day and future environmental conditions.

Micro/nanofabrication for a realistic beetle wing with a superhydrophobic surface

In keeping with the high interest in micro air vehicles, microfabrication technologies have been developed in an attempt to mimic insect wings via a membrane–vein structure. In this work, we present microfabrication techniques that mimic a beetle wing to construct a realistic vein–membrane structure. Full microfabrication processes as well as sophisticated manipulations are introduced for constructing a realistic artificial wing whose key morphological and mechanical parameters can be achieved close to those of the real wing. Secondly, for wing loading reduction whenever moist air is present, we successfully fabricated superhydrophobic nanopillar forests by conventional nanofabrication techniques, such as ion beam and heat treatments. The creation of the nanopillar forests, which exist on the surface of leaves and insect wings, allowed lowering the dispersive component in a hydrophobic material, and the clustered nanopillars enhanced water repellency.

3D computational parametric analysis of eccentric atheroma plaque: influence of axial and circumferential residual stresses

Plaque rupture plays a role in the majority of acute coronary syndromes. Rupture has usually been associated with stress concentrations, which are mainly affected by the plaque geometry and the tissue properties. The aim of this study is to evaluate the influence of morphology on the risk of plaque rupture, including the main geometrical factors, and to assess the role of circumferential and axial residual stresses by means of a parametric 3D finite element model. For this purpose, a 3D parametric finite element model of the coronary artery with eccentric atheroma plaque was developed. Healthy (adventitia and media in areas without atheroma plaque) and diseased (fibrotic and lipidic) tissues were considered in the model. The geometrical parameters used to define and design the idealized coronary plaque anatomy were the lipid core length, the stenosis ratio, the fibrous cap thickness, and the lipid core ratio. Finally, residual stresses in longitudinal and circumferential directions were incorporated into the model to analyse the influence of the important mechanical factors in the vulnerability of the plaque. Viewing the results, we conclude that residual stresses should be considered in the modelling of this kind of problems since they cause a significant alteration of the vulnerable plaque region limits. The obtained results show that the fibrous cap thickness and the lipid core length, in combination with the lipid core width, appear to be the key morphological parameters that play a determinant role in the maximal principal stress (MPS). However, the stenosis ratio is found to not play a significant role in vulnerability related to the MPS. Plaque rupture should therefore be observed as a consequence, not only of the cap thickness, but as a combination of the stenosis ratio, the fibrous cap thickness and the lipid core dimensions.

An Aerodynamic Noise Reduction Design at Inter-coach Space of High Speed Trains Based on Biomimetic Analogy

Recent years have witnessed speed up of moving vehicles such as high-speed of trains. Increase in speed entails concomitant increase in turbulent air flow which contributes toward increased aerodynamic noise. The proposed method for aerodynamic noise reduction is based on a biomimetic design of owl feather. The five morphological parameters of the owl feather are extracted from close observation, and simulation cases are constructed by applying design of experiments methodology. Swirling strength for each case is obtained through steady-state CFD analysis, and key morphological parameters that affect the turbulence are identified. Large eddy simulations (LES) are then performed on selected cases to predict the air turbulence. Different cases show varying vortex distributions which are expected to lead to varying aerodynamic noise levels.

Macroporous Hydrogel Scaffolds and Their Characterization By Optical Coherence Tomography

A simple porogen-leaching method to fabricate macroporous cyclic acetal hydrogel cell scaffolds is presented. Optical coherence tomography (OCT) was applied for nondestructive imaging and quantitative characterization of the scaffold structures. High-resolution OCT reveals the microstructures of the engineered tissue scaffolds in three dimensions. It also enables subsequent image processing to investigate quantitatively several key morphological design parameters for macroporous scaffolds, including the volume porosity, pore interconnectivity, and pore size. Two image-processing algorithms were adapted: three-dimensional labeling was applied to assess the interconnectivity, and erosion was applied to assess the pore size. Scaffolds with different design parameters were imaged, characterized, and compared. OCT imaging and image processing successfully discriminated scaffolds made from different formulations in terms of volume porosity, interconnectivity, and pore size. The cell viability and their spread across the scaffolds were confirmed by the fluorescence microscopy co-registered with OCT.

Nanoporous Metals for Catalytic and Optical Applications

AbstractNanoporous metals (NPMs) made by dealloying represent a class of functional materials with the unique structural properties of mechanical rigidity, electrical conductivity, and high corrosion resistance. They also possess a porous network structure with feature dimensions tunable within a wide range from a few nanometers to several microns. Coupled with a rich surface chemistry for further functionalization, NPMs have great potential for applications in heterogeneous catalysis, electrocatalysis, fuel cell technologies, biomolecular sensing, surface-enhanced Raman scattering (SERS), and plasmonics. This article summarizes recent advances in some of these areas and, in particular, we focus on the discussion of microstructure, catalytic, and optical properties of nanoporous gold (NPG). With advanced electron microscopy, three-dimensional tomographic reconstructions of NPG have been realized that yield quantitative characterizations of key morphological parameters involved in the intricate structure. Catalytic and electrocatalytic investigations demonstrate that bare NPG is already catalytically active for many important reactions such as CO and glucose oxidation. Surface functionalization with other metals, such as Pt, produces very efficient electrocatalysts, which have been used as promising fuel cell electrode materials with very low precious metal loading. Additionally, NPG and related materials possess outstanding optical properties in plasmonics and SERS. They hold promise to act as highly active, stable, and economically affordable substrates in high-performance instrumentation applications for chemical inspection and biomolecular diagnostics. Finally, we conclude with some perspectives that appear to warrant future investigation.

Morphological parameters for assessment of burn severity in an acute burn injury rat model

Determination of burn severity (i.e. burn depth) is important for effective medical management and treatment. Using a recently described acute burn model, we studied various morphological parameters to detect burn severity. Anaesthetized Sprague-Dawley rats received burns of various severity (0- to 14-s contact time) followed by standard resuscitation using intravenous fluids. Biopsies were taken from each site after 5 h, tissues fixed in 10% neutral-buffered formalin, processed and stained with haematoxylin and eosin. Superficial burn changes in the epidermis included early keratinocyte swelling progressing to epidermal thinning and nuclear elongation in deeper burns. Subepidermal vesicle formation generally decreased with deeper burns and typically contained grey foamy fluid. Dermal burns were typified by hyalinized collagen and a lack of detectable individual collagen fibres on a background of grey to pale eosinophilic seroproteinaceous fluid. Intact vascular structures were identified principally deep to the burn area in the collagen. Follicle cell injury was identified by cytoplasmic clearing/swelling and nuclear pyknosis, and these follicular changes were often the deepest evidence of burn injury seen for each time point. Histological scores (epidermal changes) or dermal parameter depths (dermal changes) were regressed on burn contact time. Collagen alteration (r(2) = 0.91) correlated best to burn severity followed by vascular patency (r(2) = 0.82), epidermal changes (r(2) = 0.76), subepidermal vesicle formation (r(2) = 0.74) and follicular cell injury was useful in all but deep burns. This study confirms key morphological parameters can be an important tool for the detection of burn severity in this acute burn model.