The Toxic Effect of Cu and CuO Nanoparticles on Euplotes Aediculatus

Abstract Toxicology tests were carried out by choosing Cu nanoparticles (CuNPs) and CuO nanoparticles (CuONPs) as experimental materials and Euplotes aediculatus as the experimental organism. To investigate the toxicity effect and mechanism of two NPs on E. aediculatus, we determined antioxidant enzyme activity and observed morphologic changes using optical and electron microscopes, combined with the Fourier infrared spectrum technique. The results showed that the 24 h-LC50 of CuNPs and CuONPs was 0.46 µg/L and 1.24×103 µg/L. The movement ability of cells was decreased and surface cilia gradually shed with CuNPs and CuONPs at 24 h-LC50. In addition, the cell body swelled and finally ruptured. There were varying extents of damage to the nucleus and mitochondria. With CuNPs, disappearance of nucleoli and condensation of chromatin were observed, while the mitochondria were wrinkled in an irregular shape and cristae were partially fractured. With CuONPs, changes of nucleus were not obvious, and the mitochondria were merely irregular. While neither CuNPs nor CuONPs had major effect on the ultrastructure of the membrane, some functional groups were oxidized with CuNPs, e.g. PO2-, C-O-C, δ(COH) of carbohydrates. The 24 h-EC50, 48 h-EC50 and 72 h-EC50 of CuNPs on E. aediculatus were 2.10×10-3 µg/L, 7.92×10-4 µg/L and 2.77×10-4 µg/L. The EC50 of CuONPs in same period was 7.20 µg/L, 0.86 µg/L and 0.19 µg/L. The above concentration of CuNPs and CuONPs could increase the activities of SOD, CAT and GPx, which were dose-dependent. The above results indicate that CuNPs and CuONPs inhibited reproduction and caused death. CuNPs were more toxic to E. aediculatus and more destructive to cell structure. Oxidative stress and destruction to cell structures may be toxic mechanisms. The E. aediculatus was more sensitive to CuNPs or CuONPs, and the value of 24 h-LC50 was much lower than other organisms, so it can be recommended as an indicator for early monitoring in freshwater environment.

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Computational and Experimental Studies of Cellular Samples Manufactured Using Additive Methods for Use in Advanced Lightweight Designs of Engine Parts

Volume 10B: Structures and Dynamics ◽

10.1115/gt2020-15158 ◽

2020 ◽

Author(s):

Liubov Magerramova ◽

Michael Volkov ◽

Oleg Volgin ◽

Pavel Kolos

Keyword(s):

Fatigue Testing ◽

Low Cycle Fatigue ◽

Cell Structure ◽

Experimental Studies ◽

Cellular Structures ◽

Uniaxial Tensile ◽

Porous Structures ◽

Lattice Cell ◽

Cell Structures ◽

Homogeneous Materials

Abstract The use of cellular structures is one way to reduce the weight of engine parts. Cellular structures are used to provide rigidity and strength for parts subject to compression, bending, and shock loads. Failure of the individual elements of a lattice/cell structure does not result in the destruction of the entire part; this stands in contrast to the structure of a conventional homogeneous metal object, in which cracks will continue to increase with increasing load, causing the destruction of the entire part. Lattice/cell structures have relatively high characteristics of rigidity and strength, excellent thermal insulation properties, energy absorption characteristics, and high fatigue resistance. The use of this type of structure in engine part construction opens up new opportunities for advanced aviation applications. However, the deformation behavior of porous and metallic structures differs significantly from that of conventional homogeneous materials. Samples with cellular and porous structures are themselves designs. Therefore, procedures for strength testing and interpretation of experimental results for cellular and porous structures differ from those for samples derived from homogeneous materials. The criteria for determining the properties of cellular structures include density, stiffness, ability to accumulate energy, etc. These parameters depend on the configuration of the cells, the size of each cell, and the thickness of the connecting elements. Mechanical properties of cellular structures can be established experimentally and confirmed numerically. Special cellular specimens have been designed for uniaxial tensile, bending, compression, shear, and low-cycle fatigue testing. Several variants of cell structures with relative densities ranging from 13 to 45% were considered. Specifically, the present study examined the stress-strain states of cell structures from brands “CobaltChrome MP1” powder compositions obtained by laser synthesis on an industrial 3D printer Concept Laser M2 Cusing Single Laser 400W. Numerical simulations of the tests were carried out by the finite element method. Then, the most rational cellular structures in terms of mass and strength were established on the basis of both real and numerical experiments.

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Technological Exercise of Cell Structure Forming

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.736.122 ◽

2017 ◽

Vol 736 ◽

pp. 122-126 ◽

Cited By ~ 1

Author(s):

S.N. Larin ◽

V.I. Platonov ◽

G.A. Nuzgdin

Keyword(s):

Liquid Fuel ◽

Cell Structure ◽

Experimental Studies ◽

Single Layer ◽

Processing Parameters ◽

Utilization Factor ◽

Specific Strength ◽

Cell Structures ◽

Critical Strain Rate ◽

Material Utilization

Single-layer and multi-layer cell structures are used for manufacturing of shells of liquid fuel tankers, as well as of "dry" shells of products, wings, fairings, etc. However, conventional methods of production by means of milling do not allow achieving the required specific strength. In this connection, diffusion bonding by means of gas pressure and gas forming at specified temperature and speed conditions are extremely important. Studies conducted by authors help model the processes and calculate the necessary processing parameters: pressure, critical strain rate, deformation rate (deformation time). This paper describes the manufacturing technology for these products, in which the solutions are based on theoretical and experimental studies, which provide: an increase in specific strength; reduction in weight of the product; reduction of labor intensity and increase in material utilization factor.

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Cell structure and mechanical properties of microcellular PLA foams prepared via autoclave constrained foaming

Cellular Polymers ◽

10.1177/0262489320930328 ◽

2020 ◽

pp. 026248932093032

Author(s):

Jinwei Chen ◽

Ling Yang ◽

Dahua Chen ◽

Qunshan Mai ◽

Meigui Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Cell Size ◽

Cell Structure ◽

Saturation Pressure ◽

Tensile Modulus ◽

Cell Structures ◽

Wide Range ◽

The Mean ◽

Constrained Foaming ◽

The Relationship

Microcellular polylactic acid (PLA) foams with various cell size and cell morphologies were prepared using supercritical carbon dioxide (sc-CO2) solid-state foaming to investigate the relationship between the cell structure and mechanical properties. Constrained foaming was used and a wide range of cell structures with a constant porosity of ∼75% by tuning saturation pressure (8–24 MPa) was developed. Experiments varying the saturation pressure while holding other variables’ constant show that the mean cell size and the mean cell wall thickness decreased, while the cell density and the open porosity increased with increase of pressure. Tensile modulus of PLA foams decreased with increasing the saturation pressure, but the specific tensile modulus of PLA foams was still 15–80% higher than that of solid PLA. Tensile strength and elongation at break first increased with increasing saturation pressure up to 16 MPa and then decreased with further increasing saturation pressure (20 MPa and 24 MPa) at which opened-cell structure produced. Compressive modulus, compressive strength, and compressive yield stress also followed the same variation trend. The results indicated that not only cell size plays an important role in properties of PLA foams but also cell morphology can influence these properties significantly.

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Structure-unit cell-based approach on three-dimensional representative braided preforms from four-step braiding: Experimental determination of effects of structure-process parameters on predetermined yarn path

Textile Research Journal ◽

10.1177/0040517511404597 ◽

2011 ◽

Vol 82 (3) ◽

pp. 220-241 ◽

Cited By ~ 24

Author(s):

Kadir Bilisik ◽

Nesrin Sahbaz

Keyword(s):

Cell Structure ◽

Three Dimensional ◽

Unit Cell ◽

Number Of Layers ◽

Cell Structures ◽

Cell Dimensions ◽

Unit Cell Dimensions ◽

Surface Angle ◽

Unit Cell Structure

The aim of this study was to understand the effects of braid pattern and the number of layers on three-dimensional (3D) braided unit cell structures. Various unit cell-based representative 3D braided preforms were developed. Data generated from these structures included unit cell dimensions, yarn angle, and yarn length in the unit cell structures. It was shown that braid patterns affected the 3D braided unit cell structures. The 1 × 1 braid pattern made fully interconnected integral 3D braided unit cell structures, whereas the 2 × 1 braid pattern created disconnected braid layers that were connected to the structures edges. When the number of layers increased, 3D braided unit cell thickness also increased. Braid pattern slightly affected the braider yarn angle, whereas the number of layers did not influence it. It was observed that the number of layers considerably affected the yarn length in the unit cell structure. Increasing the layer number from five to 10 layers created a yarn path in the unit cell edge regions called the ‘multilayer yarn length’. This yarn path was not observed below five-layer 3D braided unit cell structures. In jamming conditions, minimum jamming decreased the width of the unit cell structure, but maximum jamming increased its width. On the other hand, minimum jamming decreased the surface angle of the unit cell structure, whereas maximum jamming increased the surface angle. In addition, it was realized that jamming conditions influenced the density of the unit cell but did not affect the yarn length in the unit cell structures.

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Physiological, biochemical, and ultrastructural aspects of Coffea arabica L. seeds under different cryopreservation protocols

Ciência e Agrotecnologia ◽

10.1590/1413-7054202145027020 ◽

2021 ◽

Vol 45 ◽

Author(s):

Madeleine Alves de Figueiredo ◽

Sttela Dellyzete Veiga Franco da Rosa ◽

Marcela Andreotti Ricaldoni ◽

Cristiane Carvalho Pereira ◽

Stefânia Vilas Boas Coelho ◽

...

Keyword(s):

Liquid Nitrogen ◽

Water Use ◽

Coffea Arabica ◽

Cell Structure ◽

Cell Structures ◽

Key Factor ◽

Physiological Quality ◽

Ultrastructural Characteristics ◽

Coffea Arabica L ◽

Direct Immersion

ABSTRACT Cryopreservation is a technique that may potentially conserve the germplasm of species of the Coffea genus for an indeterminate time. The aim of this study was to evaluate the physiological, biochemical and ultrastructural characteristics of cryopreserved seeds of Coffea arabica L., cultivar Catucaí amarelo IAC 62, which was subjected to different protocols regarding dehydration, precooling, cooling, rewarming and cathode water use. According to each protocol, the seeds were subjected to fast or slow drying to moisture contents of 17 or 20% (wet basis), cooled in different ways, and then immersed in liquid nitrogen for 24 hours. Different rewarming times in a water bath were also used. Physiological, biochemical and ultrastructural analyses were performed on the seeds after the cryopreservation steps. Moisture content at a 17% wb is the key factor for the cryopreservation of Coffea arabica L. seeds, which have better physiological quality and better preserved cell structures. Precooling of coffee seeds before immersion in liquid nitrogen does not provide advantages compared to direct immersion. The rewarming times tested (2, 4, and 6 minutes) and cathode water use did not cause changes in the physiological and biochemical quality or in the cell structures of Coffea arabica L. cryopreserved seeds. The pattern of cell structure observed in all seeds indicates that the damage from cryopreservation is less drastic in the cells of the embryos than in those of the endosperm, with the latter less tolerant to the stresses of dehydration, precooling, and rewarming.

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Compressive properties of cell structures manufactured by photo-curing technology liquid polymer resins – Polyjet Matrix

Mechanik ◽

10.17814/mechanik.2022.1.1 ◽

2022 ◽

Vol 95 (1) ◽

pp. 12-14

Author(s):

Mateusz Rudnik

Keyword(s):

Compressive Strength ◽

Cell Structure ◽

Strength Properties ◽

Static Compression ◽

Liquid Polymer ◽

Cell Structures ◽

Strength Tests ◽

Utility Models ◽

Photo Curing ◽

Cylindrical Samples

The article presents the results of compressive strength tests of cylindrical samples with a hexagonal cell structure. The samples were made of MED 610 material using the photo-curing technology liquid polymer resins. The compressive strength was estimated on the basis of a static compression test of the printed elements. It has been shown that the PolyJet Matrix 3D printing technology enables the printing models with a thin-walled cell structure, which, while maintaining the appropriate strength properties, can be used in the design and production of certain utility models.

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Bubble Wall Rupture Model for Open Cell Structure in Starch/Fiber Heterogeneous Composites

Journal of Biobased Materials and Bioenergy ◽

10.1166/jbmb.2020.1955 ◽

2020 ◽

Vol 14 (2) ◽

pp. 169-177

Author(s):

Chuan-Wei Zhang ◽

Fang-Yi Li ◽

Jian-Feng Li ◽

Hai-Yang Lu ◽

Geng Wang

Keyword(s):

Cell Structure ◽

Local Stress ◽

Point Of View ◽

Stress Model ◽

Bubble Wall ◽

Open Cell ◽

Biodegradable Composite ◽

Cell Structures ◽

Rupture Model ◽

Conventional Models

Starch/fiber heterogeneous composites were prepared through thermos-cavity foaming machine. Open cell structures are widely distributed in the heterogeneous composites. Bubble wall rupture is an inevitable stage in the formation of open cells. Different from the conventional models to explain the bubble wall rupture from the energy and the wave point of view, this study suggests the "local thinning ultimate stress" model to reveal the bubble wall rupture from the stress perspective. The local stress of the starch bubble wall is increased with the thinning of the bubble wall. The bubble wall ruptures when local stress exceeds the ultimate surface tension. Starch slurry retraction occurs after bubble wall rupturing. The elastic retraction drives partially open cells to fully open cell morphologies in the starch/fiber heterogeneous composite. The developed mechanism was validated by starch/fiber slurry with different viscosities to design a novel biodegradable composite with fully open cell structures.

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A tube-source X-ray microtomography approach for quantitative 3D microscopy of optically challenging cell-cultured samples

Communications Biology ◽

10.1038/s42003-020-01273-w ◽

2020 ◽

Vol 3 (1) ◽

Author(s):

Ilmari Tamminen ◽

Kalle Lehto ◽

Markus Hannula ◽

Miina Ojansivu ◽

Laura Johansson ◽

...

Keyword(s):

Tissue Engineering ◽

Cell Structure ◽

Large Cell ◽

Optical Methods ◽

Cell Nuclei ◽

Tissue Engineering Scaffolds ◽

X Ray ◽

Cell Structures ◽

X Ray Imaging ◽

Spatial Coverage

Abstract Development and study of cell-cultured constructs, such as tissue-engineering scaffolds or organ-on-a-chip platforms require a comprehensive, representative view on the cells inside the used materials. However, common characteristics of biomedical materials, for example, in porous, fibrous, rough-surfaced, and composite materials, can severely disturb low-energy imaging. In order to image and quantify cell structures in optically challenging samples, we combined labeling, 3D X-ray imaging, and in silico processing into a methodological pipeline. Cell-structure images were acquired by a tube-source X-ray microtomography device and compared to optical references for assessing the visual and quantitative accuracy. The spatial coverage of the X-ray imaging was demonstrated by investigating stem-cell nuclei inside clinically relevant-sized tissue-engineering scaffolds (5x13 mm) that were difficult to examine with the optical methods. Our results highlight the potential of the readily available X-ray microtomography devices that can be used to thoroughly study relative large cell-cultured samples with microscopic 3D accuracy.

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Revisiting CdS-PbS Solar Cell Structure

MRS Proceedings ◽

10.1557/proc-1012-y12-31 ◽

2007 ◽

Vol 1012 ◽

Cited By ~ 2

Author(s):

Harumi Moreno Garcia ◽

O. Gómez-Daza ◽

J. Campos ◽

M. T. S. Nair ◽

P. K. Nair

Keyword(s):

Solar Cell ◽

Cell Structure ◽

Short Circuit ◽

Chemical Deposition ◽

Distinct Type ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Cell Structures ◽

Type V

AbstractCdS and PbS are well known semiconductor materials. Starting in 1969 and into 1970's CdS-PbS cells were reported with open circuit voltage (Voc) up to 450 mV and short circuit current density (Jsc) < 1 mA/cm2. However, further reports are scarce. These two materials are also the most investigated by chemical deposition technique. In this work we revisit this type of photovoltaic junctions and present the photovoltaic behavior of distinct type of cell structures prepared by chemical deposition: glass/CdS/PbS/Ag, SnO2:F/CdS/PbS/Ag, and SnO2:F/CdS/(Bi2S3 or/and CdSe)/PbS/Ag. Depending on the cell type, Voc of > 500 mV or Jsc of > 3 mA/cm2 could be obtained under illumination of 1-3 kW/m2. This work opens up possibilities for developing simple solar cell structures by sequential chemical deposition of semiconductors.

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The Effect of Nitrogen Bubbles on Microstructure of Natural Rubber Foams Produced by Bubbling Process

Materials Science Forum ◽

10.4028/www.scientific.net/msf.962.91 ◽

2019 ◽

Vol 962 ◽

pp. 91-95

Author(s):

Kuntida Katkeaw ◽

Benjaporn Nooklay ◽

Rungrote Kokoo ◽

Kalayanee Kooptarnond ◽

Matthana Khangkhamano

Keyword(s):

Natural Rubber ◽

Bubble Column ◽

Cell Structure ◽

Natural Rubber Latex ◽

Constant Flow ◽

Rubber Latex ◽

Bubble Volume ◽

Constant Flow Rate ◽

Cell Structures ◽

Nitrogen Bubbles

Natural rubber latex foam (NRF) was produced using nitrogen bubbling process. The process involved flowing of nitrogen with a constant flow rate of 80 cc/min through a bubble column, filled with latex compound, to generate a high bubble-volume inside the column. Microstructure of the finished product was examined using a scanning electron microscope (SEM), in comparison with that of the purchased Dunlop foam. The results showed characteristic of the as-produced foam that they composed of spherical pores with a uniform interconnected-cell structures. On the other hand, the Dunlop foam exhibited non-spherical pores and non-uniform cell structure with broken cells.

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