scholarly journals Unravelling colloid filter cake motions in membrane cleaning procedures

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Arne Lüken ◽  
John Linkhorst ◽  
Robin Fröhlingsdorf ◽  
Laura Lippert ◽  
Dirk Rommel ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Filter Cake ◽  
Membrane Surface ◽  
Cross Flow ◽  
Laser Scanning Confocal Microscopy ◽  
Scanning Confocal Microscopy ◽  
Filtration Performance ◽  
Dynamic Mobility ◽  
Cake Layer ◽  
Filter Cakes

AbstractThe filtration performance of soft colloid suspensions suffers from the agglomeration of the colloids on the membrane surface as filter cakes. Backflushing of fluid through the membrane and cross-flow flushing across the membrane are widely used methods to temporally remove the filter cake and restore the flux through the membrane. However, the phenomena occurring during the recovery of the filtration performance are not yet fully described. In this study, we filtrate poly(N-isopropylacrylamide) microgels and analyze the filter cake in terms of its composition and its dynamic mobility during removal using on-line laser scanning confocal microscopy. First, we observe uniform cake build-up that displays highly ordered and amorphous regions in the cake layer. Second, backflushing removes the cake in coherent pieces and their sizes depend on the previous cake build-up. And third, cross-flow flushing along the cake induces a pattern of longitudinal ridges on the cake surface, which depends on the cross-flow velocity and accelerates cake removal. These observations give insight into soft colloid filter cake arrangement and reveal the cake’s unique behaviour exposed to shear-stress.

scholarly journals Particle Movements Provoke Avalanche-like Compaction in Soft Colloid Filter Cakes

2021 ◽  
Author(s):  
Arne Lüken ◽  
Lucas Stüwe ◽  
Johannes Lohaus ◽  
John Linkhorst ◽  
Matthias Wessling
Keyword(s):  
Soft Matter ◽  
Filter Cake ◽  
Membrane Surface ◽  
Model Systems ◽  
Process Efficiency ◽  
Soft Particle ◽  
Compression Process ◽  
Cake Formation ◽  
Cake Layer ◽  
Filter Cakes

Abstract During soft matter filtration, colloids accumulate in a compressible porous cake layer on top of the membrane surface. The void size between the colloids predominantly defines the cake-specific permeation resistance and the corresponding filtration efficiency. While higher fluxes are beneficial for the process efficiency, they compress the cake and increase permeation resistance. However, it is not fully understood how soft particles behave during cake formation and how their compression influences the overall cake properties. This study visualizes the formation and compression process of soft filter cakes in microfluidic model systems. During cake formation, we analyze single-particle movements inside the filter cake voids and how they interact with the whole filter cake morphology. During cake compression, we visualize reversible and irreversible compression and distinguish the two phenomena. Finally, we confirm the compression phenomena by modeling the soft particle filter cake using a CFD-DEM approach. The results underline the importance of considering the compression history when describing the filter cake morphology and its related properties. Thus, this study links single colloid movements and filter cake compression to the overall cake behavior and narrows the gap between single colloid events and the filtration process.

scholarly journals Particle movements provoke avalanche-like compaction in soft colloid filter cakes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arne Lüken ◽  
Lucas Stüwe ◽  
Johannes Lohaus ◽  
John Linkhorst ◽  
Matthias Wessling
Keyword(s):  
Soft Matter ◽  
Filter Cake ◽  
Membrane Surface ◽  
Model Systems ◽  
Process Efficiency ◽  
Soft Particle ◽  
Compression Process ◽  
Cake Formation ◽  
Cake Layer ◽  
Filter Cakes

AbstractDuring soft matter filtration, colloids accumulate in a compressible porous cake layer on top of the membrane surface. The void size between the colloids predominantly defines the cake-specific permeation resistance and the corresponding filtration efficiency. While higher fluxes are beneficial for the process efficiency, they compress the cake and increase permeation resistance. However, it is not fully understood how soft particles behave during cake formation and how their compression influences the overall cake properties. This study visualizes the formation and compression process of soft filter cakes in microfluidic model systems. During cake formation, we analyze single-particle movements inside the filter cake voids and how they interact with the whole filter cake morphology. During cake compression, we visualize reversible and irreversible compression and distinguish the two phenomena. Finally, we confirm the compression phenomena by modeling the soft particle filter cake using a CFD-DEM approach. The results underline the importance of considering the compression history when describing the filter cake morphology and its related properties. Thus, this study links single colloid movements and filter cake compression to the overall cake behavior and narrows the gap between single colloid events and the filtration process.

Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

1990 ◽  
Vol 48 (3) ◽  
pp. 166-167
Author(s):  
J. Holy ◽  
G. Schatten
Keyword(s):  
Confocal Microscopy ◽  
Mitotic Spindle ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
Two Dimensions ◽  
Embryonic Cells ◽  
Mitotic Spindles ◽  
Cleavage Division ◽  
Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

Automated 3-D cell population analysis in thick tissue sections using laser-scanning confocal-microscopy data

1993 ◽  
Vol 51 ◽  
pp. 562-563
Author(s):  
Hakan Ancin
Keyword(s):  
Laser Scanning ◽  
Population Analysis ◽  
Three Dimensional ◽  
Large Data ◽  
Laser Scanning Confocal Microscopy ◽  
Tissue Slices ◽  
Scanning Confocal Microscopy ◽  
Tissue Sections ◽  
Spatially Adaptive ◽  
Microscopy Data

This paper presents methods for performing detailed quantitative automated three dimensional (3-D) analysis of cell populations in thick tissue sections while preserving the relative 3-D locations of cells. Specifically, the method disambiguates overlapping clusters of cells, and accurately measures the volume, 3-D location, and shape parameters for each cell. Finally, the entire population of cells is analyzed to detect patterns and groupings with respect to various combinations of cell properties. All of the above is accomplished with zero subjective bias.In this method, a laser-scanning confocal light microscope (LSCM) is used to collect optical sections through the entire thickness (100 - 500μm) of fluorescently-labelled tissue slices. The acquired stack of optical slices is first subjected to axial deblurring using the expectation maximization (EM) algorithm. The resulting isotropic 3-D image is segmented using a spatially-adaptive Poisson based image segmentation algorithm with region-dependent smoothing parameters. Extracting the voxels that were labelled as "foreground" into an active voxel data structure results in a large data reduction.

scholarly journals Advanced Static and Dynamic Fluorescence Microscopy Techniques to Investigate Drug Delivery Systems

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 861
Author(s):  
Jacopo Cardellini ◽  
Arianna Balestri ◽  
Costanza Montis ◽  
Debora Berti
Keyword(s):  
Drug Delivery ◽  
Fluorescence Microscopy ◽  
Drug Delivery Systems ◽  
Laser Scanning ◽  
Super Resolution ◽  
Laser Scanning Confocal Microscopy ◽  
Delivery Systems ◽  
Scanning Confocal Microscopy ◽  
Biological Phenomena

In the past decade(s), fluorescence microscopy and laser scanning confocal microscopy (LSCM) have been widely employed to investigate biological and biomimetic systems for pharmaceutical applications, to determine the localization of drugs in tissues or entire organisms or the extent of their cellular uptake (in vitro). However, the diffraction limit of light, which limits the resolution to hundreds of nanometers, has for long time restricted the extent and quality of information and insight achievable through these techniques. The advent of super-resolution microscopic techniques, recognized with the 2014 Nobel prize in Chemistry, revolutionized the field thanks to the possibility to achieve nanometric resolution, i.e., the typical scale length of chemical and biological phenomena. Since then, fluorescence microscopy-related techniques have acquired renewed interest for the scientific community, both from the perspective of instrument/techniques development and from the perspective of the advanced scientific applications. In this contribution we will review the application of these techniques to the field of drug delivery, discussing how the latest advancements of static and dynamic methodologies have tremendously expanded the experimental opportunities for the characterization of drug delivery systems and for the understanding of their behaviour in biologically relevant environments.

Observation of Fine Structure in Bicontinuous Phase-Separated Domains of a Polymer Blend by Laser Scanning Confocal Microscopy

2001 ◽  
Vol 34 (15) ◽  
pp. 5186-5191 ◽  
Author(s):  
Hiroshi Jinnai ◽  
Hiroshi Yoshida ◽  
Kohtaro Kimishima ◽  
Yoshinori Funaki ◽  
Yoshitsugu Hirokawa ◽  
...  
Keyword(s):  
Fine Structure ◽  
Confocal Microscopy ◽  
Polymer Blend ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Scanning Confocal Microscopy

scholarly journals The DNA content of trophozoites and cysts of Giardia lamblia by microdensitometric quantitation of Feulgen staining and examination by laser scanning confocal microscopy.

1994 ◽  
Vol 42 (11) ◽  
pp. 1413-1416 ◽  
Author(s):  
S L Erlandsen ◽  
E M Rasch
Keyword(s):  
Confocal Microscopy ◽  
Genome Size ◽  
Dna Content ◽  
Giardia Lamblia ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Evolutionary Development ◽  
Scanning Confocal Microscopy ◽  
Dividing Cells ◽  
C Value

We investigated direct measurement of the DNA content of the parasitic intestinal flagellate Giardia lamblia through quantitation by Feulgen microspectrophotometry and also by visualization of Feulgen-stained DNA chromosomes within dividing cells by laser scanning confocal microscopy. Individual trophozoites of Giardia (binucleate) contained 0.144 +/- 0.018 pg of DNA/cell or 0.072 pg DNA/nucleus. Giardia lamblia cysts (quadranucleate) contained 0.313 +/- 0.003 pg DNA or 0.078 pg DNA/nucleus. The genome size (C) value per nucleus ranged between 6.5-7.1 x 10(7) BP for trophozoites and cysts, respectively. Confocal microscopic examination of Giardia trophozoites undergoing binary fission revealed five chromosome-like bodies within each nucleus. Further information about genome size and DNA content within different Giardia species may help to clarify the pivotal role of these primitive eukaryotic cells in evolutionary development.

The Effect of Chloroquine on the Apoptosis Induced by Cisplatin in Human Gastric Cancer BGC823 Cells

2014 ◽  
Vol 926-930 ◽  
pp. 1124-1127
Author(s):  
Zhen Xun Jin ◽  
Li Li Zhang ◽  
Yan Wang ◽  
Lin Chuan Zeng ◽  
Yang Yu ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Confocal Microscopy ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Combination Group ◽  
Human Gastric Cancer ◽  
Apoptotic Cells ◽  
Toxic Dose ◽  
Scanning Confocal Microscopy ◽  
Mtt Tests

The aim of this study is to investigate the effects and mechanism of chloroquine (CQ) on the apoptosis induced by cisplatin in human gastric cancer BGC823 cells. MTT assay was used to detect the state of cell growth. The appearances of cellular apoptosis were detected by laser scanning confocal microscopy and light microscopy. The expressions of LC3 and p62 were detected by laser scanning confocal microscopy. MTT tests showed that the non-toxic dose of CQ could increase the inhibition rate of BGC823 cells induced by cisplatin. Under the light microscope, the ratio of apoptotic cells in the group treated with non-toxic dose of CQ combined with cisplatin was higher than that in the group treated with cisplatin alone. Hoechst33342 staining showed that the ratio of apoptotic cells in the combination group was higher than that in the cisplatin group. The expression and colocalization of LC3 and p62 proteins were significantly increased in the combination group. These results indicate that CQ can enhance the cell apoptosis induced by cisplatin in BGC823 cells, which is through the inhibition of autophagy.

In-situ Observation of Surface Relief Formation and Disappearance during Order-Disorder Transition of Equi-atomic CuAu alloy using Laser Scanning Confocal Microscopy

2004 ◽  
Vol 842 ◽  
Author(s):  
Seiji Miura ◽  
Hiroyuki Okuno ◽  
Kenji Ohkubo ◽  
Tetsuo Mohri
Keyword(s):  
Surface Relief ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Confocal Scanning Laser Microscopy ◽  
Strain Effect ◽  
In Situ Observation ◽  
Stress Effect ◽  
Scanning Confocal Microscopy ◽  
Crystallographic Orientation Relationship

ABSTRACTIn-situ observation of the formation and disappearance of the surface relief associated with the twinning during the order-disorder transitions among CuAu-I (L10), CuAu-II (PAP) and disordered fcc phases was conducted using Confocal Scanning Laser Microscopy equipped with a gold image furnace. The Retro effect was confirmed in poly-crystal samples, however no evidence was found in single-crystal samples. Also observed in poly-crystal samples are that the disordering temperature detected by the disappearing of relieves is different from grain to grain, and that grain boundary cracking alleviates the Retro effect. The observed phenomena were explained based on the crystallographic orientation relationship among grains investigated by FESEM/EBSD in terms of the elastic strain effect around grain boundaries induced by transition. It was confirmed that in each grain the surface relieves correspond to a set of two {011} planes having a <100> axis perpendicular to both planes in common. It was also found that the larger the average strain of two neighboring grains is, the lower the transition temperature. This observation was explained by the stress effect on the stability of a phase.

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