651 results
Search Results
2. Determination of cell size/structures and mechanical properties of additively manufactured metallic components using X-ray technique
- Author
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Moj, Kevin, Owsiński, Robert, Robak, Grzegorz, and Gupta, Munish Kumar
- Published
- 2023
- Full Text
- View/download PDF
3. 3D printing of bending-dominated soft lattices: numerical and experimental assessment
- Author
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Graziosi, Serena, Ballo, Federico Maria, Libonati, Flavia, and Senna, Sofia
- Published
- 2022
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4. Properties and applications of additively manufactured metallic cellular materials: A review
- Author
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Anton du Plessis, Seyed Mohammad Javad Razavi, Matteo Benedetti, Simone Murchio, Martin Leary, Marcus Watson, Dhruv Bhate, and Filippo Berto
- Subjects
architected cellular materials ,laser powder bed fusion ,stochastic systems ,metals ,product design ,foams ,cellular structures ,review papers ,lattice structures ,laser powders ,Lattice structures, Cellular structures Architected cellular materials Additive manufacturing Laser powder bed fusion Foams, Meta-materials, Porous materials ,materials properties ,Porous materials ,General Materials Science ,mechanical permeability ,cellular structure ,structural properties ,property ,cellular automata ,cellular material ,cellular manufacturing ,3D printers ,Cellular structures Architected cellular materials Additive manufacturing Laser powder bed fusion Foams ,Meta-materials ,meta-materials ,additives ,porous materials ,structural properties, architected cellular material ,powder bed ,review papers, stochastic systems ,additive manufacturing ,Lattice structures ,architected cellular material - Published
- 2022
5. Confocal Raman Spectral Imaging Study of DAPT, a γ-secretase Inhibitor, Induced Physiological and Biochemical Reponses in Osteosarcoma Cells
- Author
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Shuang Wang, Difan Wang, Jie Li, Kaige Wang, Rui Wang, Jie Qin, Qingli He, and Haishan Zeng
- Subjects
Drug ,animal structures ,media_common.quotation_subject ,Confocal ,Spectrum Analysis, Raman ,Drug Responses ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Protein structure ,Cell Line, Tumor ,Osteosarcoma cells ,medicine ,Animals ,Fragmentation (cell biology) ,media_common ,Confocal Raman microspectral imaging ,Osteosarcoma ,Principal Component Analysis ,Chemistry ,General Medicine ,Dipeptides ,medicine.disease ,Cellular Structures ,Biochemistry ,Apoptosis ,Nucleic acid ,030211 gastroenterology & hepatology ,Amyloid Precursor Protein Secretases ,Drug Screening Assays, Antitumor ,DAPT ,Function (biology) ,Cellular Heterogeneity ,Research Paper - Abstract
Confocal Raman microspectral imaging was adopted to elucidate the cellular drug responses of osteosarcoma cells (OC) to N-[N-(3, 5-difluorophenyl acetyl)-L-alanyl]-sphenylglycine butyl ester (DAPT), a γ-secretase inhibitor, by identifying the drug induced subcellular compositional and structural changes. Methods: Spectral information were acquired from cultured osteosarcoma cells treated with 0 (Untreated Group, UT), 10 (10 μM DAPT treated, 10T), 20 μM (20 μM DAPT treated, 20T) DAPT for 24 hours. A one-way ANOVA and Tukey's honest significant difference (HSD) post hoc multiple test were sequentially applied to address spectral features among three groups. Multivariate algorithms such as K-means clustering analysis (KCA) and Principal component analysis (PCA) were used to highlight the structural and compositional differences, while, univariate imaging was applied to illustrate the distribution pattern of certain cellular components after drug treatment. Results: Major biochemical changes in DAPT-induced apoptosis came from changes in the content and structure of proteins, lipids, and nucleic acids. By adopted multivariate algorithms, the drug induced cellular changes was identified by the morphology and spectral characteristics between untreated cells and treated cells, testified that DAPT mainly acted in the nuclear region. With the increase of the drug concentration, the content of main subcellular compositions, such nucleic acid, protein, and lipid decreased. In an addition, DAPT-induced nuclear fragmentation and apoptosis was depicted by the univariate Raman image of major cellular components (nucleic acids, proteins and lipids). Conclusions: The achieved Raman spectral and imaging results illustrated detailed DAPT-induced subcellular compositional and structural variations as a function of drug dose. Such observations can not only explain drug therapeutic mechanisms of OC DAPT treatment, and also provide new insights for accessing the medicine curative efficacy and predicting prognosis.
- Published
- 2020
6. Comparison of CAD Software for Designing Cellular Structures for Additive Manufacturing.
- Author
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Geyer, Sebastian and Hölzl, Christian
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COMPUTER-aided design software ,CELL anatomy ,SOFTWARE architecture ,DESIGN software ,SOFTWARE development tools - Abstract
Additive manufacturing (AM) technologies provide significant design freedom, which is highly desirable in today's fast-paced product design processes. However, most of the parametric CAD software tools used today do not fully utilize this potential for freedom of form and design. Design mechanisms, such as topology optimization (TO), generative design (GD), and lattice structures, are available on the market to help designers minimize weight and material cost while maximizing the stiffness and flexibility of planned designs. This paper proposes a benchmarking approach for designers and engineers to select a suitable software tool for lattice structure generation for their specific applications. The approach includes preselecting software tools based on a weighted point evaluation of seven significant criteria. The tools are then evaluated based on key metrics such as computing time and file size of exported structures, as well as the following six distinctive attributes: usability, reliability, availability, performance, support, and cost. The evaluation process considers a total of 32 defined features. The investigation produced clear recommendations regarding overall performance, reliability, and user experience. The findings indicate that the option of a comprehensive support offering, as well as the initial and operational costs, are significant drivers in the decision-making process. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. Numerical studies of the energy absorption capacities and deformation mechanisms of 2D cellular topologies.
- Author
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Majdak, Mateusz, Baranowski, Paweł, and Małachowski, Jerzy
- Abstract
This paper investigates the energy absorption capacities of selected cellular topologies under quasi-static loading conditions. Twenty topologies with nearly identical relative densities belonging to 4 groups were examined: honeycomb, re-entrant, bioinspired and chiral. The topologies were modeled using an experimentally validated numerical ABSplus model and subsequently subjected to in-plane uniaxial compression tests. The findings revealed the topologies with the most favorable energy absorption parameters and the main deformation mechanisms. The topologies were classified by mechanism, and a parametric study of basic material properties, namely modulus of elasticity, yield stress, and ductility, was performed for a representative topology from each mechanism. The results indicated that the honeycomb group topologies were characterized by the largest average absorbed energy, and yield stress was found to have the greatest impact on energy absorption efficiency regardless of the main deformation mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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8. The Study of the Electrical Conductivity of Apples and Grapes as an Object of Electrical Processing
- Author
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Matkarim Ibragimov, N. Eshpulatov, and Abdurahman Radjabov
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Materials science ,0211 other engineering and technologies ,02 engineering and technology ,010501 environmental sciences ,engineering.material ,01 natural sciences ,biological materials ,cellular structures ,Electrical resistance and conductance ,Electrical resistivity and conductivity ,021108 energy ,Composite material ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,lcsh:GE1-350 ,electric current ,Pulp (paper) ,fungi ,food and beverages ,Biological materials ,Tissue resistance ,Volume (thermodynamics) ,Electrode ,engineering ,Electric current ,electrical resistivity - Abstract
Experimental studies of the electrical conductivity of whole berries, peels, and pulp of apples and grapes were carried out according to the methods that the measurement voltage should not exceed the threshold and the measurement time should be minimal, and mechanical damage to the cells during contact with the electrodes was not allowed. To study the electrical conductivity (electrical resistance) of apples, grapes, and their constituent elements, a device is developed that represents a three–electrode system. The study of the specific volume resistance of the pulp of apple and grape. Development of a methodology for a three–electrode system to determine the electrical conductivity of the pulp and skin of fruits and grapes. Three–electrode system showed sufficient accuracy for apple and grape the electrical conductivity. The volumetric resistance of the skin was much greater than the pulp. The tissue resistance of fruits and grapes with an increase in the frequency of the measuring current decreases exponentially.
- Published
- 2021
9. Study on fruit flies could benefit eggs of older women.
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FRUIT flies ,OLDER women ,CYTOLOGY ,MOLECULAR biology ,CELL anatomy - Abstract
A recent study conducted at Dartmouth College on fruit flies has provided evidence that oocytes, the cells that become eggs, regularly rejuvenate the protein linkages that bind chromosomes together. This finding could potentially help older women reduce their risk of pregnancy complications as they age. As women age, their oocytes also age, leading to a loss of cohesive linkages and an increased risk of miscarriages and chromosomal abnormalities in babies. The researchers discovered that in fruit fly oocytes, new cohesive linkages form on the chromosomes to replace the originals, suggesting that rejuvenation may be possible in human oocytes as well. Further research is needed to understand this process in humans and develop therapeutic strategies to enhance rejuvenation in older women. [Extracted from the article]
- Published
- 2024
10. On the determination of residual stresses in additively manufactured lattice structures
- Author
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Giovanni Bruno, Lena Farahbod-Sternahl, Tobias Fritsch, Romeo Saliwan-Neumann, Alexander Evans, Maximilian Sprengel, and Michael Hofmann
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Work (thermodynamics) ,laser powder bed fusion ,Materials science ,Field (physics) ,Astrophysics::High Energy Astrophysical Phenomena ,High Energy Physics::Lattice ,Neutron diffraction ,Physics::Optics ,residual stress ,02 engineering and technology ,principal stress components ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Stress (mechanics) ,cellular structures ,neutron diffraction ,lattice structures ,Residual stress ,Distortion ,Orientation (geometry) ,0103 physical sciences ,Nuclear Experiment ,010302 applied physics ,Mechanics ,Neutron radiation ,021001 nanoscience & nanotechnology ,Research Papers ,Computer Science::Other ,ddc ,0210 nano-technology ,additive manufacturing - Abstract
A procedure is outlined for the neutron diffraction determination of residual stress in additively manufactured lattice structures., The determination of residual stresses becomes more complicated with increasing complexity of the structures investigated. Additive manufacturing techniques generally allow the production of ‘lattice structures’ without any additional manufacturing step. These lattice structures consist of thin struts and are thus susceptible to internal stress-induced distortion and even cracks. In most cases, internal stresses remain locked in the structures as residual stress. The determination of the residual stress in lattice structures through nondestructive neutron diffraction is described in this work. It is shown how two difficulties can be overcome: (a) the correct alignment of the lattice structures within the neutron beam and (b) the correct determination of the residual stress field in a representative part of the structure. The magnitude and the direction of residual stress are discussed. The residual stress in the strut was found to be uniaxial and to follow the orientation of the strut, while the residual stress in the knots was more hydrostatic. Additionally, it is shown that strain measurements in at least seven independent directions are necessary for the estimation of the principal stress directions. The measurement directions should be chosen according to the sample geometry and an informed choice on the possible strain field. If the most prominent direction is not measured, the error in the calculated stress magnitude increases considerably.
- Published
- 2020
11. Semi-supervised deep learning based framework for assessing manufacturability of cellular structures in direct metal laser sintering process.
- Author
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Guo, Yilin, Lu, Wen Feng, and Fuh, Jerry Ying Hsi
- Subjects
DIRECT metal laser sintering ,CELL anatomy ,DEEP learning ,SELECTIVE laser sintering - Abstract
In recent years, metal cellular structures have drawn attentions in various industrial sectors due to their design freedoms and abilities to achieve multi-functional mechanical properties. However, metal cellular structures are difficult to fabricate due to their complex geometries, even with modern additive manufacturing technologies such as the direct metal laser sintering (DMLS) process. Assessing the manufacturability of metal cellular structures via a DMLS process is a challenging task as the geometric features of the structures are complex. Besides, via a DMLS process, the manufacturability also depends on the cumulative deformation of the layers during the manufacturing process. Existing methods on Design for Additive Manufacturing (DFAM) provide design guidelines that are based on past successful printed designs. However, they are not effective in predicting the manufacturability of metal cellular structures. In this paper, we propose a semi-supervised deep learning based manufacturability assessment (SSDLMA) framework to assess whether a metal cellular structure can be successfully manufactured from a given DMLS process. To enable efficient learning, we represent the complex cellular structures as 3D binary arrays with a simple yet efficient voxelisation method. We then train a deep learning based classifier using only a small amount of experimental data by adopting a semi-supervised learning approach. By running real experiments and comparing with existing DFAM methods and machine learning models, we demonstrate the advantages of the proposed SSDLMA framework. The proposed framework can be extended to predict the manufacturability of various other complex geometries beyond cellular structure in a reliable way even with a small number of training data. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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12. A new approach for designing cellular structures: design process, manufacturing and structure analysis using a volumetric scanner.
- Author
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Moj, Kevin, Robak, Grzegorz, Owsiński, Robert, Kurek, Andrzej, Żak, Krzysztof, and Przysiężniuk, Dawid
- Subjects
VOLUMETRIC analysis ,CELL anatomy ,INJECTION molding ,COMPUTER-aided design software ,NUMERICAL control of machine tools - Abstract
while choosing 3D printing in preference to traditional manufacturing methods (injection molding, CNC machining or casting), it is worth considering optimizing spatial models for mass reduction. One method of mass reduction is to implement cellular structures into the designed component. CAD software, such as NX, Catia, Creo, SolidWorks are not suitable for this type of operation, due to the fact that they use boundary representations (b-reps) to express the shapes of solid objects. The nTopology software takes a new design approach using implicit modeling techniques. Focusing on the design aspect, the paper proposes workflows to model objects consisting of cellular structures. The emphasis is on the strength test specimens, printing them in both DMLS/SLM and SLS technologies. A volumetric scanning technique was applied to validate the produced objects, thus obtaining a real solid model of the specimens. The aim of the study was to develop configured workflows for the design of the strength test specimens. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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13. Bird's Eye View on Lattice Structures: Design Issues and Applications for Best Practices in Mechanical Design.
- Author
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Ahmad, Abas, Belluomo, Luca, Bici, Michele, and Campana, Francesca
- Subjects
UNIT cell ,DESIGN services ,PROCESS capability ,MULTISCALE modeling ,BEST practices - Abstract
Lattice structures for engineering applications are patterns of unit cells designed to make a larger functional structure. Research on lattice structures ranges in many fields, from mechanical characterization and cell and pattern designs in respect of their applications, to the manufacturing process and its final shape control. From the manufacturing point of view, some kinds of lattice structures can be infeasible when approached with traditional manufacturing methods. It may offer an inevitable limitation of their adoption. However, advancements in Additive Manufacturing (AM) have solved this manufacturing issue to a great extent, allowing to obtain major complexity of the cells that can be achieved. The topology, shape of the unit cell, and the characteristics of its replication pattern allow us to obtain many kinds of structures in respect of the different engineering requirements and manufacturing constraints. Nevertheless, the necessity of new or dedicated CAD-CAE approaches arises to manage the domains of multiscale modeling. These are some of the advantages and disadvantages that may arise while approaching the design of a component using lattice structures. The aim of this paper is to provide an overview that integrates the most recent applications of lattice structures with their related design and manufacturing issues so that, from a practical design point of view, any state-of-the-art improvements may be established in respect of the related field of applications. In this article, engineers and researchers may find a practical summary of the capabilities and processes of lattice structures that are currently available from a design and development point of view. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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14. Compression behaviour of ZPR tubular structures under axial and oblique loads.
- Author
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Burcin Erdogus, Hakan
- Abstract
The expansion of lattice-structured tubular stent causes scaffold foreshortening and artery migration during implantation. Based on stent foreshortening attitudes, studies were carried out on hybrid lattices considered Zero Poisson’s Ratio (ZPR) behaviour of arrow, auxetic, and honeycomb unit cell combinations. This paper investigates the energy performance of four ZPR tubular structures inspired by hybrid stent shapes under axial and oblique impact. At the beginning of the workflow of the study, the buckling control of tubular structures was performed using the numerical model. The compression test was performed by 3D printing of the ZPR structure, which was verified to remain uniform under axial loading. The results show that hybrid (H) tubular structures that include ZPR unit cells with different configurations have higher energy absorption and higher crushing force efficiency (CFE) under oblique impact. When the oblique angle is increased, all ZPR tubular structures are unstable from 20 to 40 mm deformation distances due to moving plate compression. H1 has a better CFE value than the other two ZPR configurations when crushed under oblique load. Furthermore, ZPR tubular structures have great advantages for axial loads without buckling behaviour. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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15. Impact Behavior Analysis of 3-D Printed Honeycomb Structures.
- Author
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STOICA, CONSTANTIN-ROMICA, MAIER, RALUCA, ISTRATE, ANCA-MIHAELA, BUCACIUC, SEBASTIAN-GABRIEL, and DESPA, ALEXANDRA
- Subjects
HONEYCOMB structures ,ENERGY absorption films ,AEROSPACE industries ,HONEYCOMBS ,COMPOSITE materials - Abstract
The purpose of this paper is to evaluate the behaviour of 3D printed honeycomb structures under low velocity impact loading for their use in energy absorption applications. Additive manufacturing technologies are part of a growing field that represents high interest for industries such as aerospace, automotive and naval. This paper aims to determine the mechanical properties of a 3D printed polymer - Polylactic Acid (PLA) manufactured by FDM (Fused Deposition Modelling) technology. In this regard, first the material is characterized by low velocity impact dynamic experimental tests. A finite Element Analysis (FEA) is performed in LS-Dyna software in order to validate the results. The samples were manufactured by varying the infill percent to investigate the influence of different parameters on a batch of samples for every configuration. The 3D CAD modelling for impact tests samples were performed in Catia V5. Among wide range of cellular structures, honeycomb non-auxetic hexagonal cell pattern was selected in this study, assuring high strength/weight ratio. The amount of energy absorbed during the impact, the failure and degradation of the impacted specimens were monitored, following the analysis of experimental and numerical data. A fair agreement was obtained between experimental and numerical results, showing that honeycomb developed lightweight structures exhibits a proper energy absorption capacity, with a mechanism of release similar to metal or composite materials honeycombs. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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16. Manufacture of Multilayer Cellular Structures Using Superplastic Forming and Diffusion Bonding for Aerospace Applications.
- Author
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Safiullin, R.
- Abstract
The paper describes the results of long-term investigations on the development of the technology of superplastic forming and diffusion bonding (SPF/DB) conducted at the Institute for Metals Superplasticity Problems, Russian Academy of Sciences for producing standard articles of aero-space engineering, such as hollow blades, wing and shell panels. The process of solid-state joint formation in titanium alloy sheets during SPF was studied. The prospects of the development of the SPF/DB technology are considered and the latest results are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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17. Bioimaging-based detection of mislocalized proteins in human cancers by semi-supervised learning
- Author
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Yang Zhang, Fan Yang, Hong-Bin Shen, and Ying-Ying Xu
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Statistics and Probability ,Normal tissue ,Semi-supervised learning ,Biology ,Machine learning ,computer.software_genre ,Biochemistry ,Neoplasms ,Biomarkers, Tumor ,Humans ,Databases, Protein ,Molecular Biology ,Protocol (object-oriented programming) ,Supplementary data ,business.industry ,Computational Biology ,Protein distribution ,Original Papers ,Cellular Structures ,Neoplasm Proteins ,Computer Science Applications ,Biomarker (cell) ,Computational Mathematics ,Computational Theory and Mathematics ,Artificial intelligence ,business ,computer ,Algorithms ,Software ,Subcellular Fractions - Abstract
Motivation: There is a long-term interest in the challenging task of finding translocated and mislocated cancer biomarker proteins. Bioimages of subcellular protein distribution are new data sources which have attracted much attention in recent years because of their intuitive and detailed descriptions of protein distribution. However, automated methods in large-scale biomarker screening suffer significantly from the lack of subcellular location annotations for bioimages from cancer tissues. The transfer prediction idea of applying models trained on normal tissue proteins to predict the subcellular locations of cancerous ones is arbitrary because the protein distribution patterns may differ in normal and cancerous states. Results: We developed a new semi-supervised protocol that can use unlabeled cancer protein data in model construction by an iterative and incremental training strategy. Our approach enables us to selectively use the low-quality images in normal states to expand the training sample space and provides a general way for dealing with the small size of annotated images used together with large unannotated ones. Experiments demonstrate that the new semi-supervised protocol can result in improved accuracy and sensitivity of subcellular location difference detection. Availability and implementation: The data and code are available at: www.csbio.sjtu.edu.cn/bioinf/SemiBiomarker/. Contact: hbshen@sjtu.edu.cn Supplementary information: Supplementary data are available at Bioinformatics online.
- Published
- 2014
18. Elastic axial stiffness properties of lattice structures: Analytical approach and experimental validation for bcc and f2cc,z unit cells.
- Author
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Bühring, J., Soika, J., Schirp-Schoenen, M., and Schröder, K.-U.
- Subjects
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UNIT cell , *STEREOLITHOGRAPHY , *YOUNG'S modulus , *ALUMINUM tubes , *LIGHTWEIGHT construction , *COMPRESSION loads , *ALUMINUM foam - Abstract
Additive manufacturing (AM) is a key technology for the individualized and resource-efficient production of structural components. Recent developments in manufacturing technologies enable improved quality of additively manufactured components and therefore they become more and more important in lightweight constructions. An example is the substitution of solid material by porous lattice structures. Those embedded lattice structures lead to highly weight-efficient structures. Most recent investigations focus on numerical and experimental studies to describe the mechanical behavior of lattice structures. In this paper, a method to determine analytical expressions for the axial stiffness properties of lattice structures is presented. The displacement method and direct stiffness method are used to derive symbolic parameter-dependent formulas for the axial stiffnesses and effective Young's moduli for f2cc,z, and bcc unit cells. Furthermore, an empirical approach based on Finite Element simulations is presented to describe the stiffness reduction for non-embedded or rather free lattice structures. The results are further validated by physical experiments. Stereolithography is used for specimen production. f2cc,z, and bcc lattice structures are embedded in thin-walled rectangular aluminum tubes and tested under compression load. Furthermore, lattices without a surrounding tube are tested. The analytical and empirical solutions are in good agreement with the experimental and numerical results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. A new model and direct slicer for lattice structures
- Author
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Mustafa, Syed Shahid and Lazoglu, Ismail
- Published
- 2021
- Full Text
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20. Model building and intelligent acquisition with application to protein subcellular location classification
- Author
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Estelle Glory-Afshar, Robert F. Murphy, Jelena Kovacevic, and C. Jackson
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Statistics and Probability ,Cell type ,Computer science ,Cells ,computer.software_genre ,Models, Biological ,Biochemistry ,Software ,Protein subcellular location ,Molecular Biology ,Likelihood Functions ,Photobleaching ,business.industry ,Process (computing) ,Proteins ,Original Papers ,Cellular Structures ,Computer Science Applications ,Computational Mathematics ,Computational Theory and Mathematics ,Data mining ,business ,Model building ,computer ,Algorithms - Abstract
Motivation: We present a framework and algorithms to intelligently acquire movies of protein subcellular location patterns by learning their models as they are being acquired, and simultaneously determining how many cells to acquire as well as how many frames to acquire per cell. This is motivated by the desire to minimize acquisition time and photobleaching, given the need to build such models for all proteins, in all cell types, under all conditions. Our key innovation is to build models during acquisition rather than as a post-processing step, thus allowing us to intelligently and automatically adapt the acquisition process given the model acquired. Results: We validate our framework on protein subcellular location classification, and show that the combination of model building and intelligent acquisition results in time and storage savings without loss of classification accuracy, or alternatively, higher classification accuracy for the same total acquisition time. Availability and implementation: The data and software used for this study will be made available upon publication at http://murphylab.web.cmu.edu/software and http://www.andrew.cmu.edu/user/jelenak/Software. Contact: jelenak@cmu.edu
- Published
- 2011
21. A spectral graph theoretic approach to quantification and calibration of collective morphological differences in cell images
- Author
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Chung Chih Lin, Yi-Hung Huang, Chun-Nan Hsu, Yuh-Show Tsai, Tien-Chuan Ku, and Yu-Shi Lin
- Subjects
Statistics and Probability ,Source code ,Acetogenins ,media_common.quotation_subject ,Feature vector ,Machine learning ,computer.software_genre ,Biochemistry ,Regularization (mathematics) ,Bottleneck ,Component analysis ,Image Interpretation, Computer-Assisted ,Calibration ,Molecular Biology ,media_common ,Mathematics ,Spectral graph theory ,business.industry ,Computational Biology ,Pattern recognition ,Ismb 2010 Conference Proceedings July 11 to July 13, 2010, Boston, Ma, Usa ,Original Papers ,Bioimaging ,Cellular Structures ,Mitochondria ,Computer Science Applications ,Computational Mathematics ,Computational Theory and Mathematics ,Graph (abstract data type) ,Artificial intelligence ,business ,computer - Abstract
Motivation: High-throughput image-based assay technologies can rapidly produce a large number of cell images for drug screening, but data analysis is still a major bottleneck that limits their utility. Quantifying a wide variety of morphological differences observed in cell images under different drug influences is still a challenging task because the result can be highly sensitive to sampling and noise. Results: We propose a graph-based approach to cell image analysis. We define graph transition energy to quantify morphological differences between image sets. A spectral graph theoretic regularization is applied to transform the feature space based on training examples of extremely different images to calibrate the quantification. Calibration is essential for a practical quantification method because we need to measure the confidence of the quantification. We applied our method to quantify the degree of partial fragmentation of mitochondria in collections of fluorescent cell images. We show that with transformation, the quantification can be more accurate and sensitive than that without transformation. We also show that our method outperforms competing methods, including neighbourhood component analysis and the multi-variate drug profiling method by Loo et al. We illustrate its utility with a study of Annonaceous acetogenins, a family of compounds with drug potential. Our result reveals that squamocin induces more fragmented mitochondria than muricin A. Availability: Mitochondrial cell images, their corresponding feature sets (SSLF and WSLF) and the source code of our proposed method are available at http://aiia.iis.sinica.edu.tw/. Contact: chunnan@iis.sinica.edu.tw Supplementary information: Supplementary data are available at Bioinformatics online.
- Published
- 2010
22. A green fluorescent protein fused to rice prolamin forms protein body-like structures in transgenic rice
- Author
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Kenji Takata, Shigeto Morita, Takehiro Masumura, Takeaki Shimada, Koichi Kishida, Shigeru Satoh, Kunisuke Tanaka, Yuhi Saito, and Hideyuki Takahashi
- Subjects
protein body ,Physiology ,Recombinant Fusion Proteins ,Green Fluorescent Proteins ,Oryza sativa ,Plant Science ,Endoplasmic Reticulum ,Plant Roots ,Green fluorescent protein ,Endosperm ,Gene Expression Regulation, Plant ,Botany ,Storage protein ,Prolamin ,Protein Structure, Quaternary ,Mercaptoethanol ,Plant Proteins ,chemistry.chemical_classification ,biology ,food and beverages ,Oryza ,Starch ,ER retention ,Plants, Genetically Modified ,Research Papers ,Genetically modified rice ,Fusion protein ,Cellular Structures ,storage protein ,Cell biology ,Plant Leaves ,Microscopy, Fluorescence ,Solubility ,chemistry ,transgenic rice ,Protein body ,Seeds ,biology.protein ,prolamin ,Molecular Chaperones ,Prolamins ,Subcellular Fractions - Abstract
Prolamins, a group of rice (Oryza sativa )s eed storage proteins, are synthesized on the rough endoplasmic reticulum (ER) and deposited in ER-derived type I protein bodies (PB-Is) in rice endosperm cells. The accumulation mechanism of prolamins, which do not possess the well-known ER retention signal, remains unclear. In order to elucidate whether the accumulation of prolamin in the ER requires seed-specific factors, the subcellular localization of the constitutively expressed green fluorescent protein fused to prolamin (prolamin– GFP) was examined in seeds, leaves, and roots of transgenic rice plants. The prolamin–GFP fusion proteins accumulated not only in the seeds but also in the leaves and roots. Microscopic observation of GFP fluorescence and immunocytochemical analysis revealed that prolamin–GFP fusion proteins specifically accumulated in PB-Is in the endosperm, whereas they were deposited in the electron-dense structures in the leaves and roots. The ER chaperone BiP was detected in the structures in the leaves and roots. The results show that the aggregation of prolamin–GFP fusion proteins does not depend on the tissues, suggesting that the prolamin–GFP fusion proteins accumulate in the ER by forming into aggregates. The findings bear out the importance of the assembly of prolamin molecules and the interaction of prolamin with BiP in the formation of ER-derived PBs.
- Published
- 2009
23. Subcellular immunocytochemical analysis detects the highest concentrations of glutathione in mitochondria and not in plastids
- Author
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Felix Mauch, Liliane Sticher, Bernd Zechmann, and Maria Müller
- Subjects
0106 biological sciences ,GPX1 ,Antioxidant ,GPX3 ,Physiology ,medicine.medical_treatment ,Arabidopsis ,Plant Science ,Biology ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,immunocytochemistry ,transmission electron microscopy ,medicine ,Plastids ,glutathione ,Cellular compartment ,030304 developmental biology ,0303 health sciences ,food and beverages ,Biological Transport ,Glutathione ,Peroxisome ,Research Papers ,Immunohistochemistry ,Cellular Structures ,Mitochondria ,Plant Leaves ,Cytosol ,chemistry ,Biochemistry ,Cytochemistry ,010606 plant biology & botany - Abstract
The tripeptide glutathione is a major antioxidant and redox buffer with multiple roles in plant metabolism. Glutathione biosynthesis is restricted to the cytosol and the plastids and the product is distributed to the various organelles by unknown mechanisms. In the present study immunogold cytochemistry based on anti-glutathione antisera and transmission electron microscopy was used to determine the relative concentration of glutathione in different organelles of Arabidopsis thaliana leaf and root cells. Glutathione-specific labelling was detected in all cellular compartments except the apoplast and the vacuole. The highest glutathione content was surprisingly not found in plastids, which have been described before as a major site of glutathione accumulation, but in mitochondria which lack the capacity for glutathione biosynthesis. Mitochondria of both leaf and root cells contained 7-fold and 4-fold, respectively, higher glutathione levels than plastids while the density of glutathione labelling in the cytosol, nuclei, and peroxisomes was intermediate. The accuracy of the glutathione labelling is supported by two observations. First, pre-adsorption of the anti-glutathione antisera with glutathione reduced the density of the gold particles in all organelles to background levels. Second, the overall glutathione-labelling density was reduced by about 90% in leaves of the glutathione-deficient Arabidopsis mutant pad2- 1 and increased in transgenic plants with enhanced glutathione accumulation. Hence, there was a strong correlation between immunocytochemical and biochemical data of glutathione accumulation. Interestingly, the glutathione labelling of mitochondria in pad2-1 remained very similar to wild-type plants thus suggesting that the high mitochondrial glutathione content is maintained in a situation of permanent glutathione-deficiency at the expense of other glutathione pools. High and constant levels of glutathione in mitochondria appear to be particularly important in cell survival strategies and it is predicted that mitochondria must have highly competitive mitochondrial glutathione uptake systems. The present results underline the suggestion that subcellular glutathione concentrations are not controlled by a global mechanism but are controlled on an individual basis and it is therefore not possible to conclude from global biochemical glutathione analysis on the status of the various organellar pools.
- Published
- 2008
24. Multifunctional design of heterogeneous cellular structures.
- Author
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Tang, Yunlong and Zhao, Yaoyao Fiona
- Subjects
TOPOLOGY ,THREE-dimensional printing ,FUNCTIONALLY gradient materials ,STRUCTURAL optimization ,MICROSTRUCTURE - Abstract
Mesoscale cellular structures with different desired physical properties are promising for a broad spectrum of applications. The availability of Additive Manufacturing (AM) technology has significantly relaxed the fabricating limitation of cellular structures. It enables the design of cellular structure with complex cell topologies and relative density distribution. In this paper, a multifunctional design method for heterogeneous cellular structures is proposed. To introduce this method, Function-Performance-Property-Design parameter model is proposed at first. This proposed model can help designers to analyze the complex relations between focused functions and their related design parameters. Based on the proposed F-P-P-D model, the template of compromise Decision Support Problem (DSP) is applied to generate the optimization formulation which can generally consider the performances defined for several different functions. To solve the defined optimization problem, a multifunctional design simulation infrastructure is proposed for the designed heterogeneous cellular structures. Based on this simulation infrastructure, both the value of the objective function and its gradients can be evaluated. Then, Sequential Quadratic Programming (SQP) solver can be applied to solve the defined optimization formulation. The optimal relative density of cellular structures can be achieved and converted to the heterogeneous cellular structures at the end. A case study is provided at the end of this paper. For this case study, two different cell topologies and several different combinations of optimization parameters are used. A brief discussion is made to conclude the effects of cell topologies and other optimization parameters on the optimization results. Generally, the result of this design case validates the efficiency of the proposed design method. This method provides a useful design tool for users to take advantage of heterogeneous cellular structures for multifunctional purposes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
25. Thermal Optimization of Additively Manufactured Lightweight Concrete Wall Elements with Internal Cellular Structure through Simulations and Measurements.
- Author
-
Briels, David, Kollmannsberger, Stefan, Leithner, Felicitas, Matthäus, Carla, Nouman, Ahmad Saleem, Oztoprak, Oguz, and Rank, Ernst
- Subjects
LIGHTWEIGHT concrete ,CELL anatomy ,CONCRETE walls ,HEAT flux measurement ,SPECIFIC gravity ,HEAT transfer - Abstract
Combining the additive manufacturing (AM) process of extrusion with lightweight concrete, mono-material but multi-functional elements with an internal cellular structure can be created to achieve good thermal performance of a wall at low resource consumption. The aim of this paper is to analyze and optimize the actual thermal performance of such a component. A sensitivity analysis and a parametric optimization were conducted based on a mathematical description of heat transfer in cellular structures. To investigate the thermal performance, 2D and 3D heat transfer simulations were used and validated by heat flux measurements on an existing prototype. A geometric optimization led to a further reduction of the U-value by up to 24%, reaching 0.58 W/m
2 K. The ratio of solid material to air inside the cells (relative density) was identified as the main driver, in addition to cell diameter, cell height, and cell wall thickness. The comparison of analytical and numerical results showed high correspondence with deviations of 3–10%, and for the experimental results 25%. These remaining deviations can be traced back to simplifications of the theoretical models and discrepancies between as designed and as built. The presented approach provides a good basis for optimizing the thermal design of complex AM components by investigating practical thermal problems with the help of 2D and 3D simulations, and thus offers a great potential for further applications. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
26. Relevance of conserved lysine and arginine residues in transmembrane helices for the transport activity of organic anion transporting polypeptide 1B3
- Author
-
H, Glaeser, K, Mandery, H, Sticht, M F, Fromm, and J, König
- Subjects
Alanine ,Estrone ,Lysine ,Cell Membrane ,Glycine ,Biological Transport, Active ,Organic Anion Transporters ,Biological Transport ,Arginine ,Research Papers ,Cellular Structures ,Protein Structure, Secondary ,Sulfobromophthalein ,Kinetics ,Pharmaceutical Preparations ,Hepatocytes ,Humans ,Pravastatin - Abstract
Organic anion transporting polypeptide 1B3 (OATP1B3) (SLCO1B3) mediates the uptake of endogenous substrates (e.g. estrone-3-sulphate) and drugs (e.g. pravastatin) from blood into hepatocytes. Structure-based modelling of OATP1B3 suggested that a pore with a positive electrostatic potential contributes to the transport mechanism. Therefore, we investigated the role of conserved positively charged amino acids for OATP1B3-mediated uptake of sulphobromophthalein (BSP) and pravastatin.Residues Lys28, Lys41 and Arg580 in OATP1B3 were substituted by alanine, arginine, glutamine, glycine or lysine. Using immunofluorescence, immunoblot analysis and cellular uptake assays, the effect of these mutations on protein expression and transport activity was investigated.Immunofluorescence revealed that all mutants were localized in the plasma membrane with partial intracellular retention of the Arg580Ala and Arg580Lys mutants. Lys41Ala, Lys41Gln, Lys41Gly, Arg580Gly and Arg580Lys showed significantly reduced transport for BSP and pravastatin. Kinetic analyses of BSP transport revealed a significant reduction of V(max) normalized to cell surface protein expression for Lys41Ala (wild type: 190 +/- 8, Lys41Ala:16 +/- 4 pmol (mg protein)(-1) min(-1), P0.001), whereas V(max) of Lys41Arg and Arg580Lys (103 +/- 8 and 123 +/- 14 pmol (mg protein)(-1) min(-1), P0.05) did not change significantly. This suggests that the positive charges at positions 41 and 580 are important for transport activity of BSP. Structural modelling indicated that the positively charged side chain of Lys41 is flexible within the pore. The orientation of Arg580 is defined by adjacent residues Glu74 and Asn77, which was confirmed by kinetic analysis of Glu74Ala.We demonstrated that the conserved positively charged amino acids Lys41 and Arg580 are pivotal to the transport activity of OATP1B3.
- Published
- 2010
27. The intermediate conductance Ca2+-activated K+ channel inhibitor TRAM-34 stimulates proliferation of breast cancer cells via activation of oestrogen receptors
- Author
-
J W, Roy, E A, Cowley, J, Blay, and P, Linsdell
- Subjects
Ion Transport ,Estradiol ,Cells ,Estrogen Receptor alpha ,Gene Expression ,Breast Neoplasms ,Estrogens ,Research Papers ,Cellular Structures ,Potassium Channels, Calcium-Activated ,Tamoxifen ,Receptors, Estrogen ,Cell Line, Tumor ,Humans ,Pyrazoles ,Calcium ,Female ,RNA, Messenger ,Receptors, Progesterone - Abstract
K(+) channels play a role in the proliferation of cancer cells. We have investigated the effects of specific K(+) channel inhibitors on basal and oestrogen-stimulated proliferation of breast cancer cells.Using the mammary adenocarcinoma cell line MCF-7 we assayed cell proliferation by radiolabelled thymidine incorporation in the absence or presence of various K(+) channel inhibitors with or without 17beta-oestradiol.Inhibitors of K(v)10.1 and K(Ca)3.1 K(+) channels suppressed basal proliferation of MCF-7 cells, but not oestrogen-stimulated proliferation. TRAM-34, a specific inhibitor of K(Ca)3.1 channels increased or decreased cell proliferation depending on the concentration. At intermediate concentrations (3-10 microM) TRAM-34 increased cell proliferation, whereas at higher concentrations (20-100 microM) TRAM-34 decreased cell proliferation. The enhancement of cell proliferation caused by TRAM-34 was blocked by the oestrogen receptor antagonists ICI182,780 and tamoxifen. TRAM-34 also increased progesterone receptor mRNA expression, decreased oestrogen receptor-alpha mRNA expression and reduced the binding of radiolabelled oestrogen to MCF-7 oestrogen receptor, in each case mimicking the effects of 17beta-oestradiol.Our results demonstrate that K(+) channels K(v)10.1 and K(Ca)3.1 play a role in basal, but not oestrogen-stimulated MCF-7 cell proliferation. TRAM-34, as well as inhibiting K(Ca)3.1, directly interacts with the oestrogen receptor and mimics the effects of 17beta-oestradiol on MCF-7 cell proliferation and gene modulation. Our finding that TRAM-34 is able to activate the oestrogen receptor suggests a novel action of this supposedly specific K(+) channel inhibitor and raises concerns of interpretation in its use.
- Published
- 2010
28. Energy Absorption Characteristics of Fused Deposition Modeling 3D Printed Auxetic Re-entrant Structures: A Review
- Author
-
Choudhry, Niranjan Kumar, Panda, Biranchi, and Dixit, Uday Shanker
- Published
- 2023
- Full Text
- View/download PDF
29. Evaluation of energy absorption capabilities and mechanical properties in FDM printed PLA TPMS structures.
- Author
-
Sankineni, Rakesh and Ravi Kumar, Y
- Abstract
Additive manufacturing is an advanced technology used to fabricate complex geometries with unique properties like cellular structures which accommodate repeated unit cells located in the x, y and z direction. These structures can be used as infill patterns due to their self-supporting structure. Among the cellular structures, Triply Periodic Minimal Surface (TPMS) structures such as Gyroid, Diamond and Schwarz Primitive (SchwarzP) structures can be tailored to produce complex structures for various applications like tissue engineering scaffolds and replace the conventional polymeric foams. TPMS structures are designed and manufactured by using the Fused Deposition Modelling (FDM) technique using Poly-Lactic Acid (PLA) as material. Among TPMS structures, Gyroid is having a unique property like structurally symmetric which design was modified to enhance the mechanical properties. The modified Gyroid or deformed Gyroid undergone a quasi-static compression test and compare the results with Diamond and SchwarzP structures. Porosity and permeability coefficients are evaluated and an optical microscope is used to verify the fabricated components. As well as, Failure patterns of the structures were evaluated and energy absorption capabilities determined. The main objective of this paper is to evaluate the impact of design and porosity on the mechanical and morphological properties of TPMS structures. In conclusion, the deformed Gyroid has more energy absorption capability up to the 11.6% strain than other TPMS structures. After 11.6% of strain, SchwarzP structure dominates. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
30. KAIST presents strategies for Holotomography in advanced bio research.
- Published
- 2024
31. Noninvasive identification of subcellular organization and nuclear morphology features associated with leukemic cells using light-scattering spectroscopy
- Author
-
Cherry Greiner, Martin Hunter, Sharad Gupta, Irene Georgakoudi, and Austin Hsiao
- Subjects
Light ,Optical Phenomena ,Mie scattering ,Biomedical Engineering ,Models, Biological ,Light scattering ,Biomaterials ,Nuclear magnetic resonance ,Reference Values ,Cell Line, Tumor ,Microscopy ,Humans ,Scattering, Radiation ,Microscopy, Interference ,Lymphocytes ,Spectroscopy ,Cell Nucleus ,Physics ,Scattering ,Spectrum Analysis ,Precursor Cell Lymphoblastic Leukemia-Lymphoma ,Light-Scattering Spectroscopy ,Cellular Structures ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optical phenomena ,Fractals ,Differential interference contrast microscopy ,Research Papers: Sensing ,Granulocytes - Abstract
Leukemia is the most common and deadly cancer among children and one of the most prevalent cancers among adults. Improvements in its diagnosis and monitoring of leukemic patients could have a significant impact in their long-term treatment. We demonstrate that light-scattering spectroscopy (LSS)-based approaches could serve as a tool to achieve this goal. Specifically, we characterize the light scattering properties of leukemic (NALM-6) cells and compare them to those of normal lymphocytes and granulocytes in the 440-710 nm range, over ±4 deg about the exact backscattering direction. We find that the LSS spectra are well described by an inverse power-law wavelength dependence, with a power exponent insensitive to the scattering angle but significantly higher for leukemic cells than for normal leukocytes. This is consistent with differences in the subcellular morphology of these cells, detected in differential interference contrast images. Furthermore, the residual light-scattering signal, extracted after subtracting the inverse power-law fit from the data, can be analyzed assuming a Gaussian distribution of spherical scatterers using Mie theory. This analysis yields scatterer sizes that are consistent with the diameters of cell nuclei and allows the detection of the larger nuclei of NALM-6 cells compared to those of lymphocytes and granulocytes.
- Published
- 2011
32. A Study of the Mechanical Properties of Materials with the Tpmes Topology by Computer Simulation.
- Author
-
Arsentiev, M. Yu., Sysoev, E. I., and Balabanov, S. V.
- Subjects
MECHANICAL behavior of materials ,STRAINS & stresses (Mechanics) ,SELECTIVE laser sintering ,COMPUTER simulation ,TOPOLOGY - Abstract
In this paper, the physical and mechanical properties of products with the geometry of a triply periodic minimal energy surfaces (TPMES) are studied by computer simulation. The calculations are performed by the FEN method (hyperelastic viscoplastic fracture with a finite deformation) for typical samples of polyamide-12 material obtained by selective laser sintering (SLS). As a result of the study using the Comsol Multiphysics program, the distribution of mechanical stresses and the appearance of deformed products at various values of the applied mechanical stress, as well as the deformation curves, were obtained. The convergence of the calculations on the mesh size of the model under study is shown. The simulation results are in close agreement with the experimental data. As a result of the study, excellent physical and mechanical characteristics of the samples with the proposed geometry are found. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
33. Engineered increase in mesophyll conductance improves photosynthetic efficiency in field trial.
- Subjects
FIELD research ,CARBON dioxide in water - Abstract
New research from the University of Illinois has shown that it is possible to engineer increased mesophyll conductance in plants, which plays a crucial role in photosynthesis. By increasing permeability and reducing the thickness of cell walls, researchers were able to improve CO2 diffusion and uptake in a model crop. This increase in mesophyll conductance could lead to increased photosynthesis without the need for more water, which is important for sustainable crop production. The team is now planning to test this modification in soybean to determine if it can improve photosynthesis, water use efficiency, and yield in a food crop. [Extracted from the article]
- Published
- 2024
34. Utilisation of industrial steel wastes in polymer composite design and its agricultural applications.
- Author
-
Lisicins, M., Lapkovskis, V., and Mironovs, V.
- Subjects
STEEL wastes ,COMPOSITE materials ,AGRICULTURAL technology ,ORGANIC wastes ,PLASTIC scrap recycling - Abstract
A constant development of agricultural activities is linked inherently to generation of significant amount of chemically aggressive organic wastes. This paper outlines a synergistic opportunity for industrial metalworking and plastic wastes recovery and re-use, with clear final product - composite steel-polymer material. Experimentally obtained composite polypropyleneperforated steel material is characterized by structural strength and stiffness provided by perforated steel tapes, and corrosion resistance assured by polypropylene layers, which protect steel from aggressive environment. Authors suppose that waste-based composite material could be applied for certain agricultural constructions, and namely, for boundary construction of farm animal feed lines and storage facilities for organic wastes and minerals. [ABSTRACT FROM AUTHOR]
- Published
- 2016
35. Fatigue of Cellular Structures - a Review.
- Author
-
Nečemer, Branko, Vesenjak, Matej, and Glodež, Srečko
- Subjects
CELL anatomy ,CONSTRUCTION materials ,THREE-dimensional printing ,POROUS materials ,FRACTURE mechanics - Abstract
A review of the fatigue and fracture behaviour of cellular structures with consideration of their fabrication and characterization is presented in this paper. The review is focused on some typical and often used cellular structures, which are divided into three main groups: (1) pre designed regular cellular structures, (2) irregular cellular structures, (3) composites with cellular cores. For each group, the current manufacturing technique is presented for producing the particular cellular structure belonging this group. Furthermore, the state-of-the-art of the fatigue behaviour is explained for the analysed cellular structures. Based on the findings in this review, it can be concluded that cellular structures show a huge potential to become important light-weight structural materials of the future with further development of additive manufacturing technologies, or with introduction of some new, more cost effective manufacturing techniques. However, the knowledge of the fatigue behaviour of these structures is poor, and should be the subject of the further investigations. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
36. Design for additive manufacturing: cellular structures in early-stage aerospace design.
- Author
-
Opgenoord, Max M. J. and Willcox, Karen E.
- Subjects
MANUFACTURING cells ,THREE-dimensional printing ,CELL anatomy ,AEROSPACE engineering ,COST estimates ,PRODUCT design - Abstract
The immense design freedom offered by additive manufacturing yields tremendous benefits, but it also raises the question of how to best go about designing components to exploit this design freedom. In early design phases, design tools need to utilize this freedom, but do so with low computational cost and with a good estimate of the final weight to correctly assess the part's influence on the overall product design. This is especially important for aerospace designs. In this paper, a design methodology is devised for cellular structures to be manufactured using additive manufacturing techniques, specifically for such early design phases. This design methodology uses adaptive meshing techniques to design the topology of the cellular structure, after which the struts of that cellular structure are optimized separately to reduce the dimensionality of the problem. The method is demonstrated for a small generic bracket and an aircraft bracket design from the literature. For these problems, our method is fast enough to evaluate many thousands of design options. This results in identifying promising candidate designs for further detailed design work. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
37. Concurrent topology optimization for cellular structures with nonuniform microstructures based on the kriging metamodel.
- Author
-
Zhang, Yan, Li, Hao, Xiao, Mi, Gao, Liang, Chu, Sheng, and Zhang, Jinhao
- Subjects
CELL anatomy ,LEVEL set methods ,FREE material ,MICROSTRUCTURE - Abstract
This paper proposes a novel multiscale concurrent topology optimization for cellular structures with continuously varying microstructures in space to obtain a superior structural performance at an affordable computation cost. At microscale, multiple prototype microstructures are topologically optimized to represent all the microstructures within macrostructure by incorporating a numerical homogenization approach into a parametric level set method (PLSM), whose connectivity is guaranteed by a kinematical connective constraint approach. A shape interpolation technology is developed to map these optimized prototype microstructures and generate a series of nonuniform microstructures, which are considered as sample points and used to construct a kriging metamodel. The built kriging metamodel is then employed to predict the effective properties of all the nonuniform microstructures within macrostructure. At macroscale, the variable thickness sheet (VTS) method is employed to generate an overall free material distribution patterns using the predicted effective properties of all the nonuniform microstructures. With the help of shape interpolation technology, all the nonuniform microstructures within macrostructure are well connected with each other due to the similar topological features at their interfaces. Using the proposed method, the macrostructural topology as well as the locations and configurations of the spatially varying nonuniform microstructures can be simultaneously optimized to ensure a sufficiently large multiscale design space. Numerical examples are provided to demonstrate the validity and advantages of the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
38. Comparison of different cellular structures for the design of selective laser melting parts through the application of a new lightweight parametric optimisation method.
- Author
-
Paz, Rubén, Monzón, Mario D., Bertrand, Philippe, and Sova, Alexey
- Abstract
Interest in lightweight geometries and cellular structures has increased due to the freeform capabilities of additive manufacturing technologies. In this paper, six different cellular structures were designed and parameterised with three design variables to carry out the lightweight optimisation of an initial solid sample. According to the limitations of conventional computer-aided design (CAD) software, a new parametric optimisation method was implemented and used to optimise these six types of structures. The best one in terms of optimisation time and stiffness was parameterised with nine design variables, changing the dimensions of the internal cellular structure and the reinforcement zones. These seven optimised geometries were manufactured in a Phenix ProX200 selective laser melting machine without using support. The samples obtained were tested under flexural load. The results show that the cubic cell structures have some advantages in terms of CAD definition, parameterisation and optimisation time because of their simpler geometry. However, from the flexural test results it can be concluded that this type of cell structure and those with horizontal bars experience a loss of stiffness compared to the estimates of the finite element analysis because of imperfections in the manufacturing process of hanging structures. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
39. Multiscale concurrent topology optimization for cellular structures with multiple microstructures based on ordered SIMP interpolation.
- Author
-
Zhang, Yan, Xiao, Mi, Li, Hao, Gao, Liang, and Chu, Sheng
- Subjects
- *
MICROSTRUCTURE , *TOPOLOGY , *MULTISCALE modeling , *COMPUTERS in economics , *INTERPOLATION , *ASYMPTOTIC homogenization - Abstract
Graphical abstract Highlights • This paper presents a novel multiscale concurrent topology optimization method. • The optimized macrostructure is composed of various types of microstructures. • An ordered SIMP model is employed to generate a macrostructural topology. • Macrostructure, microstructures and their distributions are simultaneously optimized. Abstract This paper presents a novel multiscale concurrent topology optimization method for cellular structures with various types of microstructures to obtain a superior structural performance at an affordable computation cost. At macroscale, different microstructures are regarded as different materials in a multi-material topology optimization. An ordered solid isotropic material with penalization (SIMP) interpolation model, which is efficient for solving multi-material topology optimization problems without introducing any new variables, is employed to generate an overall structure layout with predetermined multiple materials. At microscale, each macroscale element is viewed as an individual microstructure. All macroscale elements with the same material are represented by a unique microstructure. A parametric level set method (PLSM) is applied to evolve the shape and topology of the representative microstructures, whose effective properties are evaluated by a numerical homogenization method. The connectivity of adjacent microstructures is guaranteed by a kinematical connective constraint. Using the proposed method, the macrostructural topology as well as the locations and configurations of microstructures can be simultaneously optimized. Numerical examples are provided to test the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
40. Evaluation of axially-crushed cellular truss structures for crashworthiness.
- Author
-
Tripathy, Lalitendu and Wen Feng Lu
- Subjects
CRASHWORTHINESS of automobiles ,ENERGY absorption films ,ACCELERATION (Mechanics) ,FINITE element method ,THREE-dimensional printing ,TRUSSES - Abstract
Thin-walled tubes have long been used as energy absorbing structures, owing to their high specific energy absorption (SEA) capacity. But, they are associated with substantial high values of peak crush force (PCF). A high PCF results in a high deceleration pulse on the critical components and/or the passengers. This poses serious safety concerns. Even the use of triggers and grooves do not reduce the PCF considerably. To achieve improvement on the safety aspect, the research on the crashworthiness of the cellular truss structures was conducted in this paper. Finite element simulation model was developed by using ABAQUS/Explicit software and validated experimentally with structures fabricated through additive manufacturing. The truss structures were compared to the thin-walled tubes on the basis of their mass, SEA and PCF values. For an equal amount of energy absorption, while the truss structures had a higher mass, the PCFs were lowered significantly. The PCFs decreased at a rate 1.5 to 4.5 times faster than the corresponding decrease in SEAs. The example of the crash box showed that the drop in PCF due to the use of truss structure resulted in a reduction of around 5g deceleration at the cost of 1 kg of additional mass. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
41. Scientists shed light on mysteries associated with infertility.
- Subjects
INFERTILITY ,FERTILIZATION in vitro ,FEMALE infertility ,OVUM ,INTRACELLULAR space ,CELL anatomy - Abstract
Two separate studies conducted by Rutgers-led research teams have shed light on the mysteries associated with infertility. In one study, researchers found that mouse egg cells with a cap-like structure before fertilization are more likely to be viable and grow. In the second study, a gene mutation that causes an abnormal number of chromosomes in mouse eggs, a leading cause of early miscarriage and in vitro fertilization (IVF) failure, was identified. These findings have important implications for improving success rates in IVF and understanding the genetic roots of female infertility. [Extracted from the article]
- Published
- 2023
42. How ribosomes in our cells enable protein folding.
- Subjects
MOLECULAR biology ,INTRACELLULAR space ,PEPTIDES ,PROTEIN folding ,CELL anatomy - Abstract
Scientists at University College London (UCL) have discovered a new role played by ribosomes in the folding of proteins in cells. Ribosomes, which are responsible for protein synthesis, also contribute to the folding process by impacting the energy and stability of new peptide chains. The researchers found that unfolded proteins adopt expanded structures on the ribosome, while off the ribosome they become more compact and spherical. This understanding of co-translational protein folding could have implications for disease research and the development of new treatment pathways. [Extracted from the article]
- Published
- 2024
43. Investigators at Nankai University Report Findings in Robotics (Robotic Perforated Patch Clamp Based On Active Release Control of Perforating Materials).
- Published
- 2024
44. Dual action antibiotic could make bacterial resistance nearly impossible.
- Published
- 2024
45. Mission Therapeutics awarded $5.2m from The Michael J. Fox Foundation and Parkinson's UK to advance potential disease-modifying treatment MTX325.
- Subjects
PARKINSON'S disease ,THERAPEUTICS ,DUCHENNE muscular dystrophy ,NEUROLOGICAL disorders - Abstract
Mission Therapeutics has been awarded $5.2 million from The Michael J. Fox Foundation for Parkinson's Research and Parkinson's UK to advance their potential disease-modifying treatment for Parkinson's disease, called MTX325. MTX325 is a small molecule inhibitor designed to protect dopamine-producing neurons by improving mitochondrial quality and function. The funding will support a 28-day dosing of MTX325 in patients with early-stage Parkinson's disease to assess its safety, tolerability, pharmacokinetic profile, and effects on disease biology biomarkers. This grant highlights the potential of MTX325 as a disease-modifying treatment and endorses Mission Therapeutics' mitophagy strategy in human diseases. [Extracted from the article]
- Published
- 2024
46. Three-Dimensional Stiff Cellular Structures With Negative Poisson's Ratio.
- Author
-
Li, Dong, Ma, Jie, Dong, Liang, and Lakes, Roderic S.
- Subjects
POISSON'S ratio ,ELASTICITY ,FINITE element method ,THREE-dimensional printing ,SIMULATION methods & models - Abstract
In this paper, a novel three-dimensional (3D) cellular structure with negative Poisson's ratio was designed by alternating cuboid surface indents on the vertical ribs of the unit cells. The Poisson's ratio and Young's modulus of structures with different geometric parameters were determined using the finite element method (FEM) as a function of these parameters. Samples with identical geometric variables were fabricated via 3D printing, and their through-thickness direction Poisson's ratios were measured and compared with simulation results. Results showed that the Poisson's ratio of the 3D cellular structures can be tuned from positive to negative and can reach a minimal value of −0.958. Good agreement was found between the experimental results and the simulation. This lattice structure is considerably stiffer than re-entrant negative Poisson's ratio foam with the same solid phase. The design concept developed here can be optimized for specific applications via geometric parameters manipulation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
47. Researching on the Effect of Input Parameters on the Quality and Manufacturability of 3D-Printed Cellular Samples from Nylon 12 CF in Synergy with Testing Their Behavior in Bending.
- Author
-
Koroľ, Martin, Török, Jozef, Monka, Peter Pavol, Baron, Petr, Mrugalska, Beata, and Monkova, Katarina
- Subjects
BEND testing ,FUSED deposition modeling ,NYLON ,3-D printers ,CELL anatomy - Abstract
The study of cellular structures and their properties represents big potential for their future applications in real practice. The article aims to study the effect of input parameters on the quality and manufacturability of cellular samples 3D-printed from Nylon 12 CF in synergy with testing their bending behavior. Three types of structures (Schwarz Diamond, Shoen Gyroid, and Schwarz Primitive) were selected for investigation that were made via the fused deposition modeling technique. As part of the research focused on the settings of input parameters in terms of the quality and manufacturability of the samples, input parameters such as volume fraction, temperature of the working space, filament feeding method and positioning of the sample on the printing pad were specified for the combination of the used material and 3D printer. During the experimental investigation of the bending properties of the samples, a three-point bending test was performed. The dependences of force on deflection were mathematically described and the amount of absorbed energy and ductility were evaluated. The results show that among the investigated structures, the Schwarz Diamond structure appears to be the most suitable for bending stress applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Images of enzyme in action reveal secrets of antibiotic-resistant bacteria.
- Subjects
DRUG resistance in bacteria ,ENZYMES ,RIBOSOMAL proteins ,INTRACELLULAR space ,X-ray crystallography technique ,MORPHOLOGY - Abstract
Keywords: Antibacterials; Antibiotics; Antimicrobials; Bacterial Infections and Mycoses; Biochemistry; Cellular Structures; Chemistry; Cytoplasm; Cytoplasmic Structures; Drug Resistance; Drugs and Therapies; Emory University; Enzymes and Coenzymes; Genetics; Health and Medicine; Intracellular Space; Methyltransferases; Organelles; Ribosomes EN Antibacterials Antibiotics Antimicrobials Bacterial Infections and Mycoses Biochemistry Cellular Structures Chemistry Cytoplasm Cytoplasmic Structures Drug Resistance Drugs and Therapies Emory University Enzymes and Coenzymes Genetics Health and Medicine Intracellular Space Methyltransferases Organelles Ribosomes 982 982 1 08/28/23 20230901 NES 230901 2023 SEP 1 (NewsRx) -- By a News Reporter-Staff News Editor at Drug Week -- Bacteria draw from an arsenal of weapons to combat the drugs intended to kill them. The idea is to exploit differences in human cellular ribosomes and bacterial ribosomes, so that only the bacteria is targeted by an antimicrobial drug. [Extracted from the article]
- Published
- 2023
49. New Amyotrophic Lateral Sclerosis Study Findings Have Been Reported by Researchers at Ignacio Chavez National Institute of Cardiology (Characterization of Mitochondria Degeneration In Spinal Motor Neurons Triggered By Chronic Over-activation of...).
- Subjects
AMYOTROPHIC lateral sclerosis ,MOTOR neurons ,MITOCHONDRIA ,MOTOR neuron diseases ,CENTRAL nervous system - Abstract
Evidence of mitochondrial alterations during an AMPA-excitotoxic event is relevant because resembles the mitochondrial alterations previously reported in ALS patients and in transgenic familial ALS models, suggesting that a chronic excitotoxic model can be related to sporadic ALS (as has been shown in recent papers), which represent more than the 90% of the ALS cases." Keywords: Mexico City; Mexico; North and Central America; Amyotrophic Lateral Sclerosis; Cells; Cellular Structures; Central Nervous System; Cytoplasm; Cytoplasmic Structures; Efferent Neurons; Health and Medicine; Intracellular Space; Mitochondria; Motor Neurons; Neurodegenerative Diseases and Conditions; Neurons; Nutritional and Metabolic Diseases and Conditions; Organelles; Proteostasis Deficiencies; Spinal Cord; Subcellular Fractions; TDP-43 Proteinopathies EN Mexico City Mexico North and Central America Amyotrophic Lateral Sclerosis Cells Cellular Structures Central Nervous System Cytoplasm Cytoplasmic Structures Efferent Neurons Health and Medicine Intracellular Space Mitochondria Motor Neurons Neurodegenerative Diseases and Conditions Neurons Nutritional and Metabolic Diseases and Conditions Organelles Proteostasis Deficiencies Spinal Cord Subcellular Fractions TDP-43 Proteinopathies 767 767 1 07/17/23 20230721 NES 230721 2023 JUL 21 (NewsRx) -- By a News Reporter-Staff News Editor at Pain & Central Nervous System Week -- Research findings on Nutritional and Metabolic Diseases and Conditions - Amyotrophic Lateral Sclerosis are discussed in a new report. [Extracted from the article]
- Published
- 2023
50. High Strain Rate Hardening of Metallic Cellular Metamaterials
- Author
-
Novak, N., Vesenjak, M., and Ren, Z.
- Published
- 2024
- Full Text
- View/download PDF
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