scholarly journals Cytoplasmic inheritance of parent–offspring cell structure in the clonal diatom Cyclotella meneghiniana

2016 ◽  
Vol 283 (1842) ◽  
pp. 20161632 ◽  
Author(s):  
Yuka Shirokawa ◽  
Masakazu Shimada
Keyword(s):  
Genetic Model ◽  
Cell Structure ◽  
Rapid Evolution ◽  
Central Area ◽  
Cytoplasmic Inheritance ◽  
Cell Diameter ◽  
Parent Cell ◽  
Structural Inheritance ◽  
Cyclotella Meneghiniana ◽  
Inheritance System

In cytoplasmic inheritance, structural states of a parent cell could be transmitted to offspring cells via two mechanisms. The first is referred to as the hangover of parent structure, where the structure itself remains and faithfully transmits within offspring cells; the second is structural inheritance, wherein the parent structure functions as a template for development of new offspring structure. We estimated to what extent the parent structure affects the development of offspring structure by structural inheritance, using a clone of the diatom Cyclotella meneghiniana . The cell has two siliceous valves (a cell wall part at both cell poles): one is inherited from the parent and the other is newly formed. We estimated cytoplasmic heritability by comparing valve traits (central fultoportulae (CTFP), striae, central area, and cell diameter) of parent and new offspring valves, using single-cell isolation and valve labelling. Parent–offspring valve trait regressions showed that all traits, except CTFP, were significantly correlated. We formulated a quantitative genetic model considering the diatom inheritance system and revealed short-term rapid evolution compared with other inheritance systems. Diatom structural inheritance will have evolved to enable clonal populations to rapidly acquire and maintain suitable structures for temporal changes in environments and life-cycle stages.

Synergetic effect of nanoclay and nano-CaCO3 hybrid filler systems on the foaming properties and cellular structure of polystyrene nanocomposite foams using supercritical CO2

2020 ◽  
Vol 39 (5) ◽  
pp. 185-202 ◽  
Author(s):  
Xinghan Lian ◽  
Wenjie Mou ◽  
Tairong Kuang ◽  
Xianhu Liu ◽  
Shuidong Zhang ◽  
...  
Keyword(s):  
Cellular Structure ◽  
High Efficiency ◽  
Cell Structure ◽  
Synergetic Effect ◽  
Cell Diameter ◽  
Foaming Properties ◽  
Electron Microscopic ◽  
Hybrid Filler ◽  
Nanocomposite Foams ◽  
Hybrid Fillers

Supercritical fluids have been widely used to prepare various polymer nanocomposite foams due to their high-efficiency, rich-resource, and environment-friendly characteristics. In this work, we prepared polystyrene (PS) nanocomposites with different contents of hybrid fillers of nanoclay and nano-calcium carbonate (nano-CaCO3) and then were foamed by batch foaming method using supercritical carbon dioxide as a physical blowing agent. The effect of hybrid nanofillers components and foaming temperature and pressure on the foaming properties and cellular structure of PS nanocomposite foams was systematically investigated. Dynamic rheology results indicated that the complex viscosity and storage modulus were enhanced with the addition of hybrid fillers. Scanning electron microscopic images show that all samples foamed uniformly macrocells under the given conditions. More importantly, the hybrid fillers of nano-CaCO3 and nanoclay exhibit a significant synergistic effect in improving PS foaming properties, which can be ascribed to the different roles of the two fillers during cell nucleation and cell growth. For instance, the PS/0.22/0.88 nanocomposite foamed under the conditions of 20 MPa and 130°C has shown the finest cell structure (higher cell density of 1.91 × 1010 and smaller cell diameter of 2.28 µm) due to the coeffect of the hybrid nanofillers. Finally, the synergistic mechanism of these two nanofillers on PS foaming behavior was discussed.

Migration of Nanoclay in PP/PS Blend and Effect of Its Localization on Cell Structure

2008 ◽  
Author(s):  
Jun-Feng Zhao ◽  
Han-Xiong Huang
Keyword(s):  
Shear Flow ◽  
Cell Density ◽  
Cell Structure ◽  
Cell Diameter ◽  
Foaming Agent ◽  
Nucleation Sites ◽  
The Mean ◽  
Nanoclay Content ◽  
Blend Nanocomposites ◽  
Low Shear

In this work, the migration of clay in polypropylene/polystyrene (PP/PS) blend and the effect of its final localization on cell structure of microcellular foamed blend nanocomposites were studied. To observe the clay migration, a multilayered blend, alternatively superposed PS and PP/clay films with a thickness of 0.2 mm, was subjected to low shear flow. Batch foaming was performed on obtained blend nanocomposites to study the influence of the nanoclay localization on cell structure by using CO2 as the foaming agent. When subjected to flow, most clay dispersed in PP phase migrated into PS gradually. The migration of nanoclay caused smaller mean cell diameter and higher cell density to foamed PS. With the reduction of nanoclay content in PP phase, the cell density of PP foam decreased due to the reduction of heterogeneous nucleation sites and the mean cell diameter became smaller.

scholarly journals Paleoclimatic inferences based on wood growth interruptions in Late Triassic flood deposits from the southernmost Brazilian Gondwana

2021 ◽  
Vol 24 (1) ◽  
pp. 3-20
Author(s):  
Anelise Marta Siegloch ◽  
Margot Guerra-Sommer ◽  
Cesar Leandro Schultz ◽  
Eduardo Guimarães Barboza
Keyword(s):  
Ground Penetrating Radar ◽  
Central Area ◽  
High Energy ◽  
Growth Patterns ◽  
Late Triassic ◽  
Cell Diameter ◽  
Thin Sections ◽  
Climate Conditions ◽  
Ground Penetrating ◽  
Petrified Forest

The goals of this study were to establish patterns in a silicified wood assemblage to depict the evolution patterns of the Triassic paleoclimate in southern Brazilian Gondwana during an interval of global arid to semi-arid climatic context, and the taphonomic process that led to the preservation of the so-called “Petrified Forest”, which is preserved in the central area of the state of Rio Grande do Sul. Analyses were developed with an assemblage of 13 permineralized conifer wood, using standard thin sections, whose anatomical details were studied in transmitted light. Ground-Penetrating Radar was used to obtain information about the depositional characteristics of the site. Main results are: true growth rings are absent in all samples, and the boundaries of the interruption zones are marked by an abrupt decline in cell diameter, but they are not accompanied by a reduction of cell wall thickness. The subsequent reversion to normal tracheid diameter is also abrupt, revealing the return of the previous growing conditions. Ground-penetrating Radar analyses confirmed that the Mata Sequence deposits correspond to a river. The identification of growth interruption zones in a Late Triassic wood assemblage in southernmost Brazilian Gondwana (Paleobotanic Garden of the city of Mata, RS) indicates the presence of tropical, temporarily dry climate conditions, characterized by irregular, short-term environmental disturbances to growth. The taphonomic process was related to a river-channel infilling depositional process, under the influence of high-energy flood events that dragged and buried the trees. Keywords: Wood growth patterns, Mata sequence, gymnosperms, Triassic climate, petrified forest.

scholarly journals Histochemistry and morphoanatomy study on guava fruit during ripening

2012 ◽  
Vol 32 (1) ◽  
pp. 179-186 ◽  
Author(s):  
José Renato de Abreu ◽  
Custódio Donizete dos Santos ◽  
Celeste Maria Patto de Abreu ◽  
Evaristo Mauro de Castro
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Cell Structure ◽  
Central Area ◽  
Psidium Guajava ◽  
Ruthenium Red ◽  
Scanning Microscopy ◽  
Mature Stage ◽  
Guava Fruit ◽  
Scanning Electron

Guava (Psidium guajava L.) is a highly perishable fruit due to its intense metabolism during ripening. Information on the enzyme activities that degrade pectic substances, as well as the amount of pectin, is very contradictory and not clearly defined. Thus, this study aimed to monitor the changes occurred in the fruit during ripening through histochemical, physical, and scanning microscopy processes. Guavas were picked at the half-mature stage and stored for 9 days at 22 ± 1 °C and 78 ± 1% RH. The analyses conducted on the day of harvest (0) and each day of storage (1, 2, 3, 4, 5, 6, 7, and 8 days) were: firmness and histochemical analyses (ferric chloride, lugol, comassie blue, vanillin hydrochloric, and ruthenium red) observed under an optic microscope and a scanning electron microscope. Ruthenium red showed a high amount of pectin in the cell wall on day zero as well as its decrease in the wall during ripening and its accumulation in the central area of the cell. Scanning microscopy showed loss of the cell structure during ripening. Those observations suggest that the pectin is the main polymer responsible for firmness maintenance in the guava fruit.

scholarly journals Improving the Continuous Microcellular Extrusion Foaming Ability with Supercritical CO2 of Thermoplastic Polyether Ester Elastomer through In-Situ Fibrillation of Polytetrafluoroethylene

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1983 ◽  
Author(s):  
Rui Jiang ◽  
Tao Liu ◽  
Zhimei Xu ◽  
Chul B. Park ◽  
Ling Zhao
Keyword(s):  
Cell Density ◽  
Supercritical Co2 ◽  
Cell Structure ◽  
Average Diameter ◽  
Extrusion Process ◽  
Expansion Ratio ◽  
Cell Diameter ◽  
Scanning Calorimetry ◽  
Foaming Ability

In-situ fibrillated polytetrafluoroethylene (PTFE) enhanced nanocomposites were successfully prepared by mixing thermoplastic polyether ester elastomer (TPEE) and PTFE using a twin-screw extruder. Well-dispersed, long aspect ratio PTFE nanofibrils with a diameter of less than 200 nm were generated and interwoven into networks. Differential scanning calorimetry and in-situ polarized optical microscopy showed that the PTFE nanofibrils can greatly accelerate and promote crystallization of the TPEE matrix and the crystallization temperature can be increased by 6 °C. Both shearing and elongational rheometry results confirmed that the introduction of PTFE nanofibrils can significantly improve the rheological properties. The remarkable changes in the strain-hardening effect and the melt viscoelastic response, as well as the promoted crystallization, led to substantially improved foaming behavior in the continuous extrusion process using supercritical CO2 as the blowing agent. The existing PTFE nanofibrils dramatically decreased the cell diameter and increased cell density, together with a higher expansion ratio and more uniform cell structure. The sample with 5% PTFE fibrils showed the best foaming ability, with an average diameter of 10.4–14.7 μm, an expansion ratio of 9.5–12.3 and a cell density of 6.6 × 107–8.6 × 107 cells/cm3.

scholarly journals Polyurethane Foams for Domestic Sewage Treatment

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 933
Author(s):  
Ewa Dacewicz ◽  
Joanna Grzybowska-Pietras
Keyword(s):  
Cell Structure ◽  
Sewage Treatment ◽  
Ammonium Nitrogen ◽  
Domestic Sewage ◽  
Polyurethane Foams ◽  
Cell Diameter ◽  
Bacterial Cells ◽  
Sem Images ◽  
Cell Size Distribution ◽  
Sand Filter

The aim of the study was to assess the possibility of using polyurethane foams (PUF) as a filling of a foam-sand filter to directly treat domestic sewage with increased content of ammonium nitrogen and low organic carbon to nitrogen ratio (C/N). The study compared performance of two types of flexible foams: new, cylinder-shaped material (Novel Foams, NF) and waste, scrap foams (Waste Foams, WF). The foams serving as a filling of two segments of a foam-sand filter were assessed for their hydrophobic and physical properties and were tested for their cell structure, i.e., cell diameter, cell size distribution, porosity, and specific surface area. The study accounted also for selected application-related properties, such as hydrophobicity, water absorption, apparent density, dimensional stability, amount of adsorbed biomass, and the possibility of regeneration. Cell morphology was compared in reference foams, foams after 14 months of the filter operation, and regenerated foams. The experimental outcomes indicated WF as an innovative type of biomass carrier for treating domestic sewage with low C/N ratio. SEM images showed that immobilization of microorganisms in NF and WF matrices involved the formation of multi-cellular structures attached to the inner surface of the polyurethane and attachment of single bacterial cells to the foam surface. The amount of adsorbed biomass confirmed that the foam-sand filter made up of two upper layers of waste foams (with diameters and pore content of 0.50–1.53 mm and 53.0–63.5% respectively) provided highly favorable conditions for the development of active microorganisms.

Effects of ethanol content on the properties of silicone rubber foam

2020 ◽  
Vol 40 (7) ◽  
pp. 543-550
Author(s):  
Yu Tan ◽  
Jin Yao ◽  
He-Ping Zhu
Keyword(s):  
Electron Microscopy ◽  
Silicone Rubber ◽  
Cell Structure ◽  
Thermomechanical Properties ◽  
Fatigue Properties ◽  
Cross Linking ◽  
Cell Diameter ◽  
Packaging Materials ◽  
Ethanol Content ◽  
Scanning Electron

AbstractIn this study, silicone rubber foam (SF) was prepared through cross-linking and foaming. The effects of ethanol content on the SF were investigated in terms of the physical properties, static cushioning properties, dynamic thermomechanical properties, and dynamic fatigue properties. The cell structure was characterized using scanning electron microscopy and its relationship with the SF properties was analyzed. With increasing ethanol content, the cell diameter increases gradually and its uniformity deteriorates. Moreover, the density, tensile strength, and elongation at breaking of the SF samples gradually decrease. In addition, with the increase of strain and stress, the cushioning coefficient of SF decreases initially and then increases, and the fatigue times worsens with increasing ethanol content. However, fatigue process has little effect on the cushioning performance of SF, which means the SF can be used as reusable packaging materials and thereby reduce environmental pollution.

scholarly journals Struktur Sel Sekresi Daun Jeruk Kalamansi (Citrus microcarpa Bunge.) di Pulau Ambon

2021 ◽  
Vol 6 (2) ◽  
pp. 138-145
Author(s):  
Christina Horowidi ◽  
Hermalina Sinay ◽  
Ritha Lusian Karuwal ◽  
Lona Parinussa
Keyword(s):  
Secretory Cell ◽  
Cell Structure ◽  
Secretory Cells ◽  
Cell Diameter ◽  
Fresh Sample ◽  
Cell Structures ◽  
Secretory Cavities ◽  
Cell Shapes ◽  
Citrus Leaves ◽  
Dark Green

 Perbedaan lokasi tumbuh dapat mengakibatkan perbedaan penampilan fenotipik tanaman yang dapat diamati secara morfologi dan anatomi seperti struktur anatomi sel sekretori. Tujuan penelitian ini adalah untuk mengetahui struktur sel sekretori daun jeruk kalamansi di pulau Ambon. Metode jelajah dilakukan pada 13 lokasi di Pulau Ambon untuk koleksi sampel, dan pada setiap lokasi diambil 3 tanaman sebagai 3 ulangan. Tiap tanaman diambil 5 daun pada setiap sisi pohon tanaman jeruk kalamansi dengan ukuran panjang 5-7 cm dan warna hijau tua. Pembuatan preparat mengikuti metode free hand section. Pengamatan menggunakan kamera Optilab pada mikroskop Olympus dengan perbesaran 400x. Pengukuran diameter sel menggunakan fitur measure pada software Image Ruster. Data kualitatif berupa struktur sel sekresi daun jeruk Kalamansi ditampilkan dalam bentuk gambar dan dideskripsikan sesuai hasil yang terlihat, sedangkan data hasil pengukuran diameter sel sekresi adalah rerata 3 ulangan dan ditampilkan sebagai mean ± standar deviasi (SD). Hasil penelitian menunjukkan adanya sel sekretori yang berjumlah satu sel. Struktur sel sekretori terdiri dari sel epitel, sel selubung, dan rongga sekretori. Bentuk sel sekresi ada yang bulat dan lonjong. Diameter rongga sekretori berkisar antara 106,08-167,60 µm.  Berdasarkan hasil penelitian, maka dapat disimpulkan bahwa sel sekresi pada daun jeruk kalamansi pada lokasi-lokasi berbeda di Pulau Ambon bervariasi baik bentuk maupun ukurannya. Differences in habitat can induce differences in the phenotypic appearance of plants that can be observed morphologically and anatomically such as the anatomical structure of secretory cells. The purpose of this study was to determine the structure of the secretory cells in the leaves of Calamansy citrus in Ambon island. Tracking method was done for sample collections, and at each location 3 plants were taken as replicates. Each plant was taken 5 leaves with a length of 5-7 cm and dark green color. Prior to be observed, the fresh sample was done with free-hand section method.   Microscopy observations were done by a light microscope at 400x magnification. Measurement of cell diameter was done by the measure feature in Image Ruster software.  Qualitative data such as secretory cell structures of Calamansy citrus leaves were shown in form of images and described according to the results, while the data of the measurement of secretory cell diameters is the average of 3 replications and was shown as mean ± standard deviation (SD).  The results showed the presence of secretory cells which amounted to one cell. The secretory cell structure is composed of epithelial cells, sheath cells, and secretory cavities. Cell shapes vary, including round and oval. The diameter of the secretory cell cavity ranges from 106.08-167.60 µm.   

Cellular Structure Control of Aluminum Foams Based on Semi-Solid Forming Technology

2011 ◽  
Vol 233-235 ◽  
pp. 2710-2713
Author(s):  
Xiao Hong You ◽  
Fang Wang ◽  
Lu Cai Wang
Keyword(s):  
Cell Structure ◽  
Mixing Time ◽  
Heating Time ◽  
Cell Diameter ◽  
Optimal Parameters ◽  
Aluminum Foams ◽  
Two Stage ◽  
Foaming Process ◽  
Forming Technology ◽  
Semi Solid

Based on making principle of aluminum foams and semi-soild forming technology, a two-stage foaming process for Al-Si alloy foam named Semi-Solid Foaming (SSF) was put forward in this paper in order to control the cell structure of closed-cell aluminum foam. On the basis of introducing basic technology of SSF, effects of process parameters on foaming process and cell structure was investigated to obtain optimal parameters. The results show that the decomposing time of TiH2 can be controlled and two-stage foaming process, i.e. SSF, has been realized, to obtain Al-Si alloy foam of relatively homogenious cell structure with porosity of 74.6%, cell diameter ranging from 2.1mm to 3.2mm（average value is 2.3mm），and average circularity of 0.812. It is clarified that optimal parameters are as follows:agitation temperature is 580,the mixing time is 0.5min,the mixing speed is 1200r/min，re-foaming temperature of furnace is 720 and the heating time is 15min on condition of experiment.

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