Magnetic cell sorting purification of differentiated embryonic stem cells stably expressing truncated human CD4 as surface marker.

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David, Robert; Groebner, Michael; Franz, Wolfgang-Michael

2005-04-01

Embryonic stem (ES) cells offer great potential in regenerative medicine and tissue engineering. Clinical applications are still hampered by the lack of protocols for gentle, high-yield isolation of specific cell types for transplantation expressing no immunogenic markers. We describe labeling of stably transfected ES cells expressing a human CD4 molecule lacking its intracellular domain (DeltaCD4) under control of the phosphoglycerate kinase promoter for magnetic cell sorting (MACS). To track the labeled ES cells, we fused DeltaCD4 to an intracellular enhanced green fluorescent protein domain (DeltaCD4EGFP). We showed functionality of the membrane-bound fluorescent fusion protein and its suitability for MACS leading to purities greater than 97%. Likewise, expression of DeltaCD4 yielded up to 98.5% positive cells independently of their differentiation state. Purities were not limited by the initial percentage of DeltaCD4(+) cells, ranging from 0.6%-16%. The viability of MACS-selected cells was demonstrated by reaggregation and de novo formation of embryoid bodies developing all three germ layers. Thus, expression of DeltaCD4 in differentiated ES cells may enable rapid, high-yield purification of a desired cell type for tissue engineering and transplantation studies.

Engineering quadrupole magnetic flow sorting for the isolation of pancreatic islets

Energy Technology Data Exchange (ETDEWEB)

Kennedy, David J. [IKOtech, LLC, 3130 Highland Avenue, 3rd Floor, Cincinnati, OH 45219-2374 (United States)]. E-mail: David.Kennedy@IKOtech.com; Todd, Paul [SHOT, Inc., Greenville, IN (United States); Logan, Sam [SHOT, Inc., Greenville, IN (United States); Becker, Matthew [SHOT, Inc., Greenville, IN (United States); Papas, Klearchos K. [Diabetes Institute for Immunology and Transplantation, University of Minnesota, Minneapolis, MN (United States); Moore, Lee R. [Biomedical Engineering Department, Cleveland Clinic Foundation, Cleveland, OH (United States)

2007-04-15

Quadrupole magnetic flow sorting (QMS) is being adapted from the separation of suspensions of single cells (<15 {mu}m) to the isolation of pancreatic islets (150-350 {mu}m) for transplant. To achieve this goal, the critical QMS components have been modeled and engineered to optimize the separation process. A flow channel has been designed, manufactured, and tested. The quadrupole magnet assembly has been designed and verified by finite element analysis. Pumps have been selected and verified by test. Test data generated from the pumps and flow channel demonstrate that the fabricated channel and peristaltic pumps fulfill the requirements of successful QMS separation.

Engineering quadrupole magnetic flow sorting for the isolation of pancreatic islets

International Nuclear Information System (INIS)

Kennedy, David J.; Todd, Paul; Logan, Sam; Becker, Matthew; Papas, Klearchos K.; Moore, Lee R.

2007-01-01

Quadrupole magnetic flow sorting (QMS) is being adapted from the separation of suspensions of single cells (<15 μm) to the isolation of pancreatic islets (150-350 μm) for transplant. To achieve this goal, the critical QMS components have been modeled and engineered to optimize the separation process. A flow channel has been designed, manufactured, and tested. The quadrupole magnet assembly has been designed and verified by finite element analysis. Pumps have been selected and verified by test. Test data generated from the pumps and flow channel demonstrate that the fabricated channel and peristaltic pumps fulfill the requirements of successful QMS separation

CellSort: a support vector machine tool for optimizing fluorescence-activated cell sorting and reducing experimental effort.

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Yu, Jessica S; Pertusi, Dante A; Adeniran, Adebola V; Tyo, Keith E J

2017-03-15

High throughput screening by fluorescence activated cell sorting (FACS) is a common task in protein engineering and directed evolution. It can also be a rate-limiting step if high false positive or negative rates necessitate multiple rounds of enrichment. Current FACS software requires the user to define sorting gates by intuition and is practically limited to two dimensions. In cases when multiple rounds of enrichment are required, the software cannot forecast the enrichment effort required. We have developed CellSort, a support vector machine (SVM) algorithm that identifies optimal sorting gates based on machine learning using positive and negative control populations. CellSort can take advantage of more than two dimensions to enhance the ability to distinguish between populations. We also present a Bayesian approach to predict the number of sorting rounds required to enrich a population from a given library size. This Bayesian approach allowed us to determine strategies for biasing the sorting gates in order to reduce the required number of enrichment rounds. This algorithm should be generally useful for improve sorting outcomes and reducing effort when using FACS. Source code available at http://tyolab.northwestern.edu/tools/ . k-tyo@northwestern.edu. Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Fundamentals and Application of Magnetic Particles in Cell Isolation and Enrichment

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Plouffe, Brian D.; Murthy, Shashi K.; Lewis, Laura H.

2014-01-01

Magnetic sorting using magnetic beads has become a routine methodology for the separation of key cell populations from biological suspensions. Due to the inherent ability of magnets to provide forces at a distance, magnetic cell manipulation is now a standardized process step in numerous processes in tissue engineering, medicine, and in fundamental biological research. Herein we review the current status of magnetic particles to enable isolation and separation of cells, with a strong focus on the fundamental governing physical phenomena, properties and syntheses of magnetic particles and on current applications of magnet-based cell separation in laboratory and clinical settings. We highlight the contribution of cell separation to biomedical research and medicine and detail modern cell separation methods (both magnetic and non-magnetic). In addition to a review of the current state-of-the-art in magnet-based cell sorting, we discuss current challenges and available opportunities for further research, development and commercialization of magnetic particle-based cell separation systems. PMID:25471081

Cloning of Plasmodium falciparum by single-cell sorting.

Science.gov (United States)

Miao, Jun; Li, Xiaolian; Cui, Liwang

2010-10-01

Malaria parasite cloning is traditionally carried out mainly by using the limiting dilution method, which is laborious, imprecise, and unable to distinguish multiply-infected RBCs. In this study, we used a parasite engineered to express green fluorescent protein (GFP) to evaluate a single-cell sorting method for rapidly cloning Plasmodium falciparum. By dividing a two-dimensional scattergram from a cell sorter into 17 gates, we determined the parameters for isolating singly-infected erythrocytes and sorted them into individual cultures. Pre-gating of the engineered parasites for GFP allowed the isolation of almost 100% GFP-positive clones. Compared with the limiting dilution method, the number of parasite clones obtained by single-cell sorting was much higher. Molecular analyses showed that parasite isolates obtained by single-cell sorting were highly homogenous. This highly efficient single-cell sorting method should prove very useful for cloning both P. falciparum laboratory populations from genetic manipulation experiments and clinical samples. Copyright 2010 Elsevier Inc. All rights reserved.

Cloning of Plasmodium falciparum by single-cell sorting

Science.gov (United States)

Miao, Jun; Li, Xiaolian; Cui, Liwang

2010-01-01

Malaria parasite cloning is traditionally carried out mainly by using the limiting dilution method, which is laborious, imprecise, and unable to distinguish multiply-infected RBCs. In this study, we used a parasite engineered to express green fluorescent protein (GFP) to evaluate a single-cell sorting method for rapidly cloning Plasmodium falciparum. By dividing a two dimensional scattergram from a cell sorter into 17 gates, we determined the parameters for isolating singly-infected erythrocytes and sorted them into individual cultures. Pre-gating of the engineered parasites for GFP allowed the isolation of almost 100% GFP-positive clones. Compared with the limiting dilution method, the number of parasite clones obtained by single-cell sorting was much higher. Molecular analyses showed that parasite isolates obtained by single-cell sorting were highly homogenous. This highly efficient single-cell sorting method should prove very useful for cloning both P. falciparum laboratory populations from genetic manipulation experiments and clinical samples. PMID:20435038

Fundamentals and application of magnetic particles in cell isolation and enrichment: a review

International Nuclear Information System (INIS)

Plouffe, Brian D; Murthy, Shashi K; Lewis, Laura H

2015-01-01

Magnetic sorting using magnetic beads has become a routine methodology for the separation of key cell populations from biological suspensions. Due to the inherent ability of magnets to provide forces at a distance, magnetic cell manipulation is now a standardized process step in numerous processes in tissue engineering, medicine, and in fundamental biological research. Herein we review the current status of magnetic particles to enable isolation and separation of cells, with a strong focus on the fundamental governing physical phenomena, properties and syntheses of magnetic particles and on current applications of magnet-based cell separation in laboratory and clinical settings. We highlight the contribution of cell separation to biomedical research and medicine and detail modern cell-separation methods (both magnetic and non-magnetic). In addition to a review of the current state-of-the-art in magnet-based cell sorting, we discuss current challenges and available opportunities for further research, development and commercialization of magnetic particle-based cell-separation systems. (review article)

Magnetic measurement, sorting optimization and adjustment of SDUV-FEL hybrid undulator

International Nuclear Information System (INIS)

Wang Tao; Jia Qika

2007-01-01

Construction of an undulator includes magnet block measurement, sorting, field measurement and adjustment. Optimizing SDUV-FEL undulator by simulated annealing algorithm using measurement results of the magnet blocks by Helmholtz coil before installing undulator magnets, the cost function can be reduced by three orders of magnitude. The practical parameters of one segment meet the design specifications after adjusting the magnetic field. (authors)

Monocytes isolated by positive and negative magnetic sorting techniques show different molecular characteristics and immunophenotypic behaviour [version 3; referees: 2 approved

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Jashdeep Bhattacharjee

2018-03-01

Full Text Available Background: Magnetic sorting of cells, based on  microbead conjugated antibodies (Abs, employs positive as well as negative immunomagnetic separation methods, for isolation of a specific cell population. These microbeads are suggested to be nontoxic, biodegradable carriers conjugated to various antibodies. Isolation of cells through positive selection involves the attachment of antibody conjugated microbeads to the cells of interest, followed by their isolation in the presence of a strong magnetic field to obtain higher purity. Negative selection involves attachment of microbead conjugated antibodies to all other cell populations except the cells of interest, which remain untagged. In the present study, we compared the two methods for their effect on functional and immunophenotypic behavior of isolated CD14+ monocytes. Methods: Peripheral blood mononuclear cells (PBMCs were isolated from blood collected from healthy volunteers by density gradient centrifugation. Human blood derived monocytes were isolated through positive selection and negative selection, making use of the appropriate monocyte isolation kit. Monocytes were then stimulated with lipopolysaccharide (LPS and their activation and proliferation capacity were examined. The degradation or dissociation of cell-bound microbeads was also investigated. Results: We observed an impaired LPS sensitivity as well as poor activation and proliferation capacity upon stimulation by LPS in positively sorted CD14+ monocytes as compared to negatively sorted CD14+ monocytes. The attached microbeads did not degrade and remained attached to the cells even after 6 days of culture. Conclusions: Our results suggest that positively sorted CD14+ cells exhibit hampered functionality and may result in inaccurate analysis and observations in downstream applications. However, these cells can be used for immediate analytical procedures.

Sorting live stem cells based on Sox2 mRNA expression.

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Hans M Larsson

Full Text Available While cell sorting usually relies on cell-surface protein markers, molecular beacons (MBs offer the potential to sort cells based on the presence of any expressed mRNA and in principle could be extremely useful to sort rare cell populations from primary isolates. We show here how stem cells can be purified from mixed cell populations by sorting based on MBs. Specifically, we designed molecular beacons targeting Sox2, a well-known stem cell marker for murine embryonic (mES and neural stem cells (NSC. One of our designed molecular beacons displayed an increase in fluorescence compared to a nonspecific molecular beacon both in vitro and in vivo when tested in mES and NSCs. We sorted Sox2-MB(+SSEA1(+ cells from a mixed population of 4-day retinoic acid-treated mES cells and effectively isolated live undifferentiated stem cells. Additionally, Sox2-MB(+ cells isolated from primary mouse brains were sorted and generated neurospheres with higher efficiency than Sox2-MB(- cells. These results demonstrate the utility of MBs for stem cell sorting in an mRNA-specific manner.

Transcriptional profiling of cells sorted by RNA abundance

NARCIS (Netherlands)

Klemm, Sandy; Semrau, Stefan; Wiebrands, Kay; Mooijman, Dylan; Faddah, Dina A; Jaenisch, Rudolf; van Oudenaarden, Alexander

We have developed a quantitative technique for sorting cells on the basis of endogenous RNA abundance, with a molecular resolution of 10-20 transcripts. We demonstrate efficient and unbiased RNA extraction from transcriptionally sorted cells and report a high-fidelity transcriptome measurement of

Standard practice for cell sorting in a BSL-3 facility.

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Perfetto, Stephen P; Ambrozak, David R; Nguyen, Richard; Roederer, Mario; Koup, Richard A; Holmes, Kevin L

2011-01-01

Over the past decade, there has been a rapid growth in the number of BSL-3 and BSL-4 laboratories in the USA and an increase in demand for infectious cell sorting in BSL-3 laboratories. In 2007, the International Society for Advancement of Cytometry (ISAC) Biosafety Committee published standards for the sorting of unfixed cells and is an important resource for biosafety procedures when performing infectious cell sorting. Following a careful risk assessment, if it is determined that a cell sorter must be located within a BSL-3 laboratory, there are a variety of factors to be considered prior to the establishment of the laboratory. This chapter outlines procedures for infectious cell sorting in a BSL-3 environment to facilitate the establishment and safe operation of a BSL-3 cell sorting laboratory. Subjects covered include containment verification, remote operation, disinfection, personal protective equipment (PPE), and instrument-specific modifications for enhanced aerosol evacuation.

Rapid assay for cell age response to radiation by electronic volume flow cell sorting

International Nuclear Information System (INIS)

Freyer, J.P.; Wilder, M.E.; Raju, M.R.

1987-01-01

A new technique is described for measuring cell survival as a function of cell cycle position using flow cytometric cell sorting on the basis of electronic volume signals. Sorting of cells into different cell age compartments is demonstrated for three different cell lines commonly used in radiobiological research. Using flow cytometric DNA content analysis and [ 3 H]thymidine autoradiography of the sorted cell populations, it is demonstrated that resolution of the age compartment separation is as good as or better than that reported for other cell synchronizing techniques. Variation in cell survival as a function of position in the cell cycle after a single dose of radiation as measured by volume cell sorting is similar to that determined by other cell synchrony techniques. Advantages of this method include: (1) no treatment of the cells is required, thus, this method is noncytotoxic; (2) no cell cycle progression is needed to obtain different cell age compartments; (3) the cell population can be held in complete growth medium at any desired temperature during sorting; (4) a complete radiation age - response assay can be plated in 2 h. Applications of this method are discussed, along with some technical limitations. (author)

Radiation Response of Cancer Stem-Like Cells From Established Human Cell Lines After Sorting for Surface Markers

International Nuclear Information System (INIS)

Al-Assar, Osama; Muschel, Ruth J.; Mantoni, Tine S.; McKenna, W. Gillies; Brunner, Thomas B.

2009-01-01

Purpose: A subpopulation of cancer stem-like cells (CSLC) is hypothesized to exist in different cancer cell lines and to mediate radioresistance in solid tumors. Methods and Materials: Cells were stained for CSLC markers and sorted (fluorescence-activated cell sorter/magnetic beads) to compare foci and radiosensitivity of phosphorylated histone H2AX at Ser 139 (γ-H2AX) in sorted vs. unsorted populations in eight cell lines from different organs. CSLC properties were examined using anchorage-independent growth and levels of activated Notch1. Validation consisted of testing tumorigenicity and postirradiation enrichment of CSLC in xenograft tumors. Results: The quantity of CSLC was generally in good agreement with primary tumors. CSLC from MDA-MB-231 (breast) and Panc-1 and PSN-1 (both pancreatic) cells had fewer residual γ-H2AX foci than unsorted cells, pointing to radioresistance of CSLC. However, only MDA-MB-231 CSLC were more radioresistant than unsorted cells. Furthermore, MDA-MB-231 CSLC showed enhanced anchorage-independent growth and overexpression of activated Notch1 protein. The expression of cancer stem cell surface markers in the MDA-MB-231 xenograft model was increased after exposure to fractionated radiation. In contrast to PSN-1 cells, a growth advantage for MDA-MB-231 CSLC xenograft tumors was found compared to tumors arising from unsorted cells. Conclusions: CSLC subpopulations showed no general radioresistant phenotype, despite the quantities of CSLC subpopulations shown to correspond relatively well in other reports. Likewise, CSLC characteristics were found in some but not all of the tested cell lines. The reported problems in testing for CSLC in cell lines may be overcome by additional techniques, beyond sorting for markers.

Dielectrophoretic focusing integrated pulsed laser activated cell sorting

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Zhu, Xiongfeng; Kung, Yu-Chun; Wu, Ting-Hsiang; Teitell, Michael A.; Chiou, Pei-Yu

2017-08-01

We present a pulsed laser activated cell sorter (PLACS) integrated with novel sheathless size-independent dielectrophoretic (DEP) focusing. Microfluidic fluorescence activated cell sorting (μFACS) systems aim to provide a fully enclosed environment for sterile cell sorting and integration with upstream and downstream microfluidic modules. Among them, PLACS has shown a great potential in achieving comparable performance to commercial aerosol-based FACS (>90% purity at 25,000 cells sec-1). However conventional sheath flow focusing method suffers a severe sample dilution issue. Here we demonstrate a novel dielectrophoresis-integrated pulsed laser activated cell sorter (DEP-PLACS). It consists of a microfluidic channel with 3D electrodes laid out to provide a tunnel-shaped electric field profile along a 4cmlong channel for sheathlessly focusing microparticles/cells into a single stream in high-speed microfluidic flows. All focused particles pass through the fluorescence detection zone along the same streamline regardless of their sizes and types. Upon detection of target fluorescent particles, a nanosecond laser pulse is triggered and focused in a neighboring channel to generate a rapidly expanding cavitation bubble for precise sorting. DEP-PLACS has achieved a sorting purity of 91% for polystyrene beads at a throughput of 1,500 particle/sec.

IAP-Based Cell Sorting Results in Homogeneous Transplantable Dopaminergic Precursor Cells Derived from Human Pluripotent Stem Cells

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Daniela Lehnen

2017-10-01

Full Text Available Human pluripotent stem cell (hPSC-derived mesencephalic dopaminergic (mesDA neurons can relieve motor deficits in animal models of Parkinson's disease (PD. Clinical translation of differentiation protocols requires standardization of production procedures, and surface-marker-based cell sorting is considered instrumental for reproducible generation of defined cell products. Here, we demonstrate that integrin-associated protein (IAP is a cell surface marker suitable for enrichment of hPSC-derived mesDA progenitor cells. Immunomagnetically sorted IAP+ mesDA progenitors showed increased expression of ventral midbrain floor plate markers, lacked expression of pluripotency markers, and differentiated into mature dopaminergic (DA neurons in vitro. Intrastriatal transplantation of IAP+ cells sorted at day 16 of differentiation in a rat model of PD resulted in functional recovery. Grafts from sorted IAP+ mesDA progenitors were more homogeneous in size and DA neuron density. Thus, we suggest IAP-based sorting for reproducible prospective enrichment of mesDA progenitor cells in clinical cell replacement strategies.

IAP-Based Cell Sorting Results in Homogeneous Transplantable Dopaminergic Precursor Cells Derived from Human Pluripotent Stem Cells.

Science.gov (United States)

Lehnen, Daniela; Barral, Serena; Cardoso, Tiago; Grealish, Shane; Heuer, Andreas; Smiyakin, Andrej; Kirkeby, Agnete; Kollet, Jutta; Cremer, Harold; Parmar, Malin; Bosio, Andreas; Knöbel, Sebastian

2017-10-10

Human pluripotent stem cell (hPSC)-derived mesencephalic dopaminergic (mesDA) neurons can relieve motor deficits in animal models of Parkinson's disease (PD). Clinical translation of differentiation protocols requires standardization of production procedures, and surface-marker-based cell sorting is considered instrumental for reproducible generation of defined cell products. Here, we demonstrate that integrin-associated protein (IAP) is a cell surface marker suitable for enrichment of hPSC-derived mesDA progenitor cells. Immunomagnetically sorted IAP + mesDA progenitors showed increased expression of ventral midbrain floor plate markers, lacked expression of pluripotency markers, and differentiated into mature dopaminergic (DA) neurons in vitro. Intrastriatal transplantation of IAP + cells sorted at day 16 of differentiation in a rat model of PD resulted in functional recovery. Grafts from sorted IAP + mesDA progenitors were more homogeneous in size and DA neuron density. Thus, we suggest IAP-based sorting for reproducible prospective enrichment of mesDA progenitor cells in clinical cell replacement strategies. Copyright © 2017 Miltenyi Biotec GmbH. Published by Elsevier Inc. All rights reserved.

Coupling Bacterial Activity Measurements with Cell Sorting by Flow Cytometry.

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Servais; Courties; Lebaron; Troussellier

1999-08-01

> Abstract A new procedure to investigate the relationship between bacterial cell size and activity at the cellular level has been developed; it is based on the coupling of radioactive labeling of bacterial cells and cell sorting by flow cytometry after SYTO 13 staining. Before sorting, bacterial cells were incubated in the presence of tritiated leucine using a procedure similar to that used for measuring bacterial production by leucine incorporation and then stained with SYTO 13. Subpopulations of bacterial cells were sorted according to their average right-angle light scatter (RALS) and fluorescence. Average RALS was shown to be significantly related to the average biovolume. Experiments were performed on samples collected at different times in a Mediterranean seawater mesocosm enriched with nitrogen and phosphorus. At four sampling times, bacteria were sorted in two subpopulations (cells smaller and larger than 0.25 µm(3)). The results indicate that, at each sampling time, the growth rate of larger cells was higher than that of smaller cells. In order to confirm this tendency, cell sorting was performed on six subpopulations differing in average biovolume during the mesocosm follow-up. A clear increase of the bacterial growth rates was observed with increasing cell size for the conditions met in this enriched mesocosm.http://link.springer-ny.com/link/service/journals/00248/bibs/38n2p180.html

Continuous Size-Dependent Sorting of Ferromagnetic Nanoparticles in Laser-Ablated Microchannel

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Yiqiang Fan

2016-01-01

Full Text Available This paper reports a low-cost method of continuous size-dependent sorting of magnetic nanoparticles in polymer-based microfluidic devices by magnetic force. A neodymium permanent magnet was used to generate a magnetic field perpendicular to the fluid flow direction. Firstly, FeNi3 magnetic nanoparticles were chemically synthesized with diameter ranges from 80 nm to 200 nm; then, the solution of magnetic nanoparticles and a buffer were passed through the microchannel in laminar flow; the magnetic nanoparticles were deflected from the flow direction under the applied magnetic field. Nanoparticles in the microchannel will move towards the direction of high-gradient magnetic fields, and the degree of deflection depends on their sizes; therefore, magnetic nanoparticles of different sizes can be separated and finally collected from different output ports. The proposed method offers a rapid and continuous approach of preparing magnetic nanoparticles with a narrow size distribution from an arbitrary particle size distribution. The proposed new method has many potential applications in bioanalysis field since magnetic nanoparticles are commonly used as solid support for biological entities such as DNA, RNA, virus, and protein. Other than the size sorting application of magnetic nanoparticles, this approach could also be used for the size sorting and separation of naturally magnetic cells, including blood cells and magnetotactic bacteria.

Lipid vesicle-mediated affinity chromatography using magnetic activated cell sorting (LIMACS): a novel method to analyze protein-lipid interaction.

Science.gov (United States)

Bieberich, Erhard

2011-04-26

The analysis of lipid protein interaction is difficult because lipids are embedded in cell membranes and therefore, inaccessible to most purification procedures. As an alternative, lipids can be coated on flat surfaces as used for lipid ELISA and Plasmon resonance spectroscopy. However, surface coating lipids do not form microdomain structures, which may be important for the lipid binding properties. Further, these methods do not allow for the purification of larger amounts of proteins binding to their target lipids. To overcome these limitations of testing lipid protein interaction and to purify lipid binding proteins we developed a novel method termed lipid vesicle-mediated affinity chromatography using magnetic-activated cell sorting (LIMACS). In this method, lipid vesicles are prepared with the target lipid and phosphatidylserine as the anchor lipid for Annexin V MACS. Phosphatidylserine is a ubiquitous cell membrane phospholipid that shows high affinity to the protein Annexin V. Using magnetic beads conjugated to Annexin V the phosphatidylserine-containing lipid vesicles will bind to the magnetic beads. When the lipid vesicles are incubated with a cell lysate the protein binding to the target lipid will also be bound to the beads and can be co-purified using MACS. This method can also be used to test if recombinant proteins reconstitute a protein complex binding to the target lipid. We have used this method to show the interaction of atypical PKC (aPKC) with the sphingolipid ceramide and to co-purify prostate apoptosis response 4 (PAR-4), a protein binding to ceramide-associated aPKC. We have also used this method for the reconstitution of a ceramide-associated complex of recombinant aPKC with the cell polarity-related proteins Par6 and Cdc42. Since lipid vesicles can be prepared with a variety of sphingo- or phospholipids, LIMACS offers a versatile test for lipid-protein interaction in a lipid environment that resembles closely that of the cell membrane

Separation and sorting of cells in microsystems using physical principles

Science.gov (United States)

Lee, Gi-Hun; Kim, Sung-Hwan; Ahn, Kihoon; Lee, Sang-Hoon; Park, Joong Yull

2016-01-01

In the last decade, microfabrication techniques have been combined with microfluidics and applied to cell biology. Utilizing such new techniques, various cell studies have been performed for the research of stem cells, immune cells, cancer, neurons, etc. Among the various biological applications of microtechnology-based platforms, cell separation technology has been highly regarded in biological and clinical fields for sorting different types of cells, finding circulating tumor cells (CTCs), and blood cell separation, amongst other things. Many cell separation methods have been created using various physical principles. Representatively, these include hydrodynamic, acoustic, dielectrophoretic, magnetic, optical, and filtering methods. In this review, each of these methods will be introduced, and their physical principles and sample applications described. Each physical principle has its own advantages and disadvantages. The engineers who design the systems and the biologists who use them should understand the pros and cons of each method or principle, to broaden the use of microsystems for cell separation. Continuous development of microsystems for cell separation will lead to new opportunities for diagnosing CTCs and cancer metastasis, as well as other elements in the bloodstream.

Quantitative Magnetic Separation of Particles and Cells Using Gradient Magnetic Ratcheting.

Science.gov (United States)

Murray, Coleman; Pao, Edward; Tseng, Peter; Aftab, Shayan; Kulkarni, Rajan; Rettig, Matthew; Di Carlo, Dino

2016-04-13

Extraction of rare target cells from biosamples is enabling for life science research. Traditional rare cell separation techniques, such as magnetic activated cell sorting, are robust but perform coarse, qualitative separations based on surface antigen expression. A quantitative magnetic separation technology is reported using high-force magnetic ratcheting over arrays of magnetically soft micropillars with gradient spacing, and the system is used to separate and concentrate magnetic beads based on iron oxide content (IOC) and cells based on surface expression. The system consists of a microchip of permalloy micropillar arrays with increasing lateral pitch and a mechatronic device to generate a cycling magnetic field. Particles with higher IOC separate and equilibrate along the miropillar array at larger pitches. A semi-analytical model is developed that predicts behavior for particles and cells. Using the system, LNCaP cells are separated based on the bound quantity of 1 μm anti-epithelial cell adhesion molecule (EpCAM) particles as a metric for expression. The ratcheting cytometry system is able to resolve a ±13 bound particle differential, successfully distinguishing LNCaP from PC3 populations based on EpCAM expression, correlating with flow cytometry analysis. As a proof-of-concept, EpCAM-labeled cells from patient blood are isolated with 74% purity, demonstrating potential toward a quantitative magnetic separation instrument. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of magnet sorting using a simple resonance cancellation method on the RMS orbit distortion at the APS injector synchrotron

International Nuclear Information System (INIS)

Lopez, F.; Koul, R.; Mills, F.E.

1993-01-01

The Advanced Photon Source injector synchrotron is a 7-GeV positron machine with a standard alternating gradient lattice. The calculated effect of dipole magnet strength errors on the orbit distortion, simulated by Monte Carlo, was reduced by sorting pairs of magnets having the closest simulated measured strengths to reduce the driving the term of the integer resonance nearest the operating point. This method resulted in a factor of four average reduction in the rms orbit distortion when all 68 magnets were sorted at once. The simulated effect of magnet measurement experimental resolution was found to limit the actual improvement. The Β-beat factors were similarly reduced by sorting the quadrupole magnets according to their gradients

Pulsed laser activated cell sorter (PLACS) for high-throughput fluorescent mammalian cell sorting

Science.gov (United States)

Chen, Yue; Wu, Ting-Hsiang; Chung, Aram; Kung, Yu-Chung; Teitell, Michael A.; Di Carlo, Dino; Chiou, Pei-Yu

2014-09-01

We present a Pulsed Laser Activated Cell Sorter (PLACS) realized by exciting laser induced cavitation bubbles in a PDMS microfluidic channel to create high speed liquid jets to deflect detected fluorescent samples for high speed sorting. Pulse laser triggered cavitation bubbles can expand in few microseconds and provide a pressure higher than tens of MPa for fluid perturbation near the focused spot. This ultrafast switching mechanism has a complete on-off cycle less than 20 μsec. Two approaches have been utilized to achieve 3D sample focusing in PLACS. One is relying on multilayer PDMS channels to provide 3D hydrodynamic sheath flows. It offers accurate timing control of fast (2 m sec-1) passing particles so that synchronization with laser bubble excitation is possible, an critically important factor for high purity and high throughput sorting. PLACS with 3D hydrodynamic focusing is capable of sorting at 11,000 cells/sec with >95% purity, and 45,000 cells/sec with 45% purity using a single channel in a single step. We have also demonstrated 3D focusing using inertial flows in PLACS. This sheathless focusing approach requires 10 times lower initial cell concentration than that in sheath-based focusing and avoids severe sample dilution from high volume sheath flows. Inertia PLACS is capable of sorting at 10,000 particles sec-1 with >90% sort purity.

Computational cell model based on autonomous cell movement regulated by cell-cell signalling successfully recapitulates the "inside and outside" pattern of cell sorting

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Ajioka Itsuki

2007-09-01

Full Text Available Abstract Background Development of multicellular organisms proceeds from a single fertilized egg as the combined effect of countless numbers of cellular interactions among highly dynamic cells. Since at least a reminiscent pattern of morphogenesis can be recapitulated in a reproducible manner in reaggregation cultures of dissociated embryonic cells, which is known as cell sorting, the cells themselves must possess some autonomous cell behaviors that assure specific and reproducible self-organization. Understanding of this self-organized dynamics of heterogeneous cell population seems to require some novel approaches so that the approaches bridge a gap between molecular events and morphogenesis in developmental and cell biology. A conceptual cell model in a computer may answer that purpose. We constructed a dynamical cell model based on autonomous cell behaviors, including cell shape, growth, division, adhesion, transformation, and motility as well as cell-cell signaling. The model gives some insights about what cellular behaviors make an appropriate global pattern of the cell population. Results We applied the model to "inside and outside" pattern of cell-sorting, in which two different embryonic cell types within a randomly mixed aggregate are sorted so that one cell type tends to gather in the central region of the aggregate and the other cell type surrounds the first cell type. Our model can modify the above cell behaviors by varying parameters related to them. We explored various parameter sets with which the "inside and outside" pattern could be achieved. The simulation results suggested that direction of cell movement responding to its neighborhood and the cell's mobility are important for this specific rearrangement. Conclusion We constructed an in silico cell model that mimics autonomous cell behaviors and applied it to cell sorting, which is a simple and appropriate phenomenon exhibiting self-organization of cell population. The model

Accurately tracking single-cell movement trajectories in microfluidic cell sorting devices.

Science.gov (United States)

Jeong, Jenny; Frohberg, Nicholas J; Zhou, Enlu; Sulchek, Todd; Qiu, Peng

2018-01-01

Microfluidics are routinely used to study cellular properties, including the efficient quantification of single-cell biomechanics and label-free cell sorting based on the biomechanical properties, such as elasticity, viscosity, stiffness, and adhesion. Both quantification and sorting applications require optimal design of the microfluidic devices and mathematical modeling of the interactions between cells, fluid, and the channel of the device. As a first step toward building such a mathematical model, we collected video recordings of cells moving through a ridged microfluidic channel designed to compress and redirect cells according to cell biomechanics. We developed an efficient algorithm that automatically and accurately tracked the cell trajectories in the recordings. We tested the algorithm on recordings of cells with different stiffness, and showed the correlation between cell stiffness and the tracked trajectories. Moreover, the tracking algorithm successfully picked up subtle differences of cell motion when passing through consecutive ridges. The algorithm for accurately tracking cell trajectories paves the way for future efforts of modeling the flow, forces, and dynamics of cell properties in microfluidics applications.

Accurately tracking single-cell movement trajectories in microfluidic cell sorting devices.

Directory of Open Access Journals (Sweden)

Jenny Jeong

Full Text Available Microfluidics are routinely used to study cellular properties, including the efficient quantification of single-cell biomechanics and label-free cell sorting based on the biomechanical properties, such as elasticity, viscosity, stiffness, and adhesion. Both quantification and sorting applications require optimal design of the microfluidic devices and mathematical modeling of the interactions between cells, fluid, and the channel of the device. As a first step toward building such a mathematical model, we collected video recordings of cells moving through a ridged microfluidic channel designed to compress and redirect cells according to cell biomechanics. We developed an efficient algorithm that automatically and accurately tracked the cell trajectories in the recordings. We tested the algorithm on recordings of cells with different stiffness, and showed the correlation between cell stiffness and the tracked trajectories. Moreover, the tracking algorithm successfully picked up subtle differences of cell motion when passing through consecutive ridges. The algorithm for accurately tracking cell trajectories paves the way for future efforts of modeling the flow, forces, and dynamics of cell properties in microfluidics applications.

A multiple objective magnet sorting algorithm for the ALS insertion devices

International Nuclear Information System (INIS)

Humphries, D.; Goetz, F.; Kownacki, P.; Marks, S.; Schlueter, R.

1994-07-01

Insertion devices for the Advanced Light Source (ALS) incorporate large numbers of permanent magnets which have a variety of magnetization orientation errors. These orientation errors can produce field errors which affect both the spectral brightness of the insertion devices and the storage ring electron beam dynamics. A perturbation study was carried out to quantify the effects of orientation errors acting in a hybrid magnetic structure. The results of this study were used to develop a multiple stage sorting algorithm which minimizes undesirable integrated field errors and essentially eliminates pole excitation errors. When applied to a measured magnet population for an existing insertion device, an order of magnitude reduction in integrated field errors was achieved while maintaining near zero pole excitation errors

Magnetic Sorting of the Regolith on the Moon: Lunar Swirls

Science.gov (United States)

Pieters, C. M.; Garrick-Bethell, I.; Hemingway, D.

2014-12-01

All of the mysterious albedo features on the Moon called "lunar swirls" are associated with magnetic anomalies, but not all magnetic anomalies are associated with lunar swirls [1]. It is often hypothesized that the albedo markings are tied to immature regolith on the surface, perhaps due to magnetic shielding of the solar wind and prevention of normal space weathering of the soil. Although interaction of the solar wind with the surface at swirls is indeed affected by the local magnetic field [2], this does not appear to result in immature soils on the surface. Calibrated spectra from the Moon Mineralogy Mapper [M3] (in image format) demonstrate that the high albedo markings for swirls are simply not consistent with immature regolith as is now understood from detailed analyses of lunar samples [eg 3]. However, M3 data show that the high albedo features of swirls are distinct and quite different from normal soils (in both the highlands and the mare). They allexhibit a flatter continuum across the near-infrared, but the actual band strength of ferrous minerals shows little (if any) deviation [4]. Recent analyses of magnetic field direction at swirls [5] mimic the observed albedo patterns (horizontal surface fields in bright areas, vertical surface fields in dark lanes). When coupled with the optical properties of magnetic separates of lunar soils [6] and our knowledge that the magnetic component of the soil results from space weathering [3,6], we propose a new and very simple explanation for these enigmatic albedo markings: the lunar swirls result from magnetic sorting of a well developed regolith. With time, normal gardening of the soil over a magnetic anomaly causes some of the dark magnetic component of the soil to be gradually removed from regions (high albedo areas) and accumulated in others (dark lanes). We are modeling predicted sorting rates using realistic rates of dust production. If this mechanism is tenable, only the origin of these magnetic anomalies

Numerical Model of Streaming DEP for Stem Cell Sorting

Directory of Open Access Journals (Sweden)

Rucha Natu

2016-11-01

Full Text Available Neural stem cells are of special interest due to their potential in neurogenesis to treat spinal cord injuries and other nervous disorders. Flow cytometry, a common technique used for cell sorting, is limited due to the lack of antigens and labels that are specific enough to stem cells of interest. Dielectrophoresis (DEP is a label-free separation technique that has been recently demonstrated for the enrichment of neural stem/progenitor cells. Here we use numerical simulation to investigate the use of streaming DEP for the continuous sorting of neural stem/progenitor cells. Streaming DEP refers to the focusing of cells into streams by equilibrating the dielectrophoresis and drag forces acting on them. The width of the stream should be maximized to increase throughput while the separation between streams must be widened to increase efficiency during retrieval. The aim is to understand how device geometry and experimental variables affect the throughput and efficiency of continuous sorting of SC27 stem cells, a neurogenic progenitor, from SC23 cells, an astrogenic progenitor. We define efficiency as the ratio between the number of SC27 cells over total number of cells retrieved in the streams, and throughput as the number of SC27 cells retrieved in the streams compared to their total number introduced to the device. The use of cylindrical electrodes as tall as the channel yields streams featuring >98% of SC27 cells and width up to 80 µm when using a flow rate of 10 µL/min and sample cell concentration up to 105 cells/mL.

Sphingolipid trafficking and protein sorting in epithelial cells

NARCIS (Netherlands)

Slimane, TA; Hoekstra, D

2002-01-01

Sphingolipids represent a minor, but highly dynamic subclass of lipids in all eukaryotic cells. They are involved in functions that range from structural protection to signal transduction and protein sorting, and participate in lipid raft assembly. In polarized epithelial cells, which display an

Optical sorting and photo-transfection of mammalian cells

CSIR Research Space (South Africa)

Mthunzi, P

2010-02-01

Full Text Available and that the scattering force can enable sorting through axial guiding onto laminin coated glass coverslips upon which the selected cells adhere. Following this, I report on transient photo-transfection of mammalian cells including neuroblastomas (rat/mouse and human...

Aminopeptidase N is directly sorted to the apical domain in MDCK cells

DEFF Research Database (Denmark)

Wessels, H P; Hansen, Gert Helge; Fuhrer, C

1990-01-01

In different epithelial cell types, integral membrane proteins appear to follow different sorting pathways to the apical surface. In hepatocytes, several apical proteins were shown to be transported there indirectly via the basolateral membrane, whereas in MDCK cells a direct sorting pathway from...

Basis for paleoenvironmental interpretation of magnetic properties of sediment from Upper Klamath Lake (Oregon): Effects of weathering and mineralogical sorting

Science.gov (United States)

Rosenbaum, J.G.; Reynolds, R.L.

2004-01-01

Studies of magnetic properties enable reconstruction of environmental conditions that affected magnetic minerals incorporated in sediments from Upper Klamath Lake. Analyses of stream sediment samples from throughout the catchment of Upper Klamath Lake show that alteration of Fe-oxide minerals during subaerial chemical weathering of basic volcanic rocks has significantly changed magnetic properties of surficial deposits. Titanomagnetite, which is abundant both as phenocrysts and as microcrystals in fresh volcanic rocks, is progressively destroyed during weathering. Because fine-grained magnetite is readily altered due to large surface-to-volume ratios, weathering causes an increase in average magnetic grain size as well as reduction in the quantity of titanomagnetite both absolutely and relative to hematite. Hydrodynamic mineralogical sorting also produces differences in magnetic properties among rock and mineral grains of differing sizes. Importantly, removal of coarse silicate and Fe-oxide grains by sorting concentrated extremely fine-grained magnetite in the resulting sediment. The effects of weathering and sorting of minerals cannot be completely separated. These processes combine to produce the magnetic properties of a non-glacial lithic component of Upper Klamath Lake sediments, which is characterized by relatively low magnetite content and coarse magnetic grain size. Hydrodynamic sorting alone causes significant differences between the magnetic properties of glacial flour in lake sediments and of fresh volcanic rocks in the catchment. In comparison to source volcanic rocks, glacial flour in the lake sediment is highly enriched in extremely fine-grained magnetite.

Sex-sorting sperm using flow cytometry/cell sorting.

Science.gov (United States)

Garner, Duane L; Evans, K Michael; Seidel, George E

2013-01-01

The sex of mammalian offspring can be predetermined by flow sorting relatively pure living populations of X- and Y-chromosome-bearing sperm. This method is based on precise staining of the DNA of sperm with the nucleic acid-specific fluorophore, Hoechst 33342, to differentiate between the subpopulations of X- and Y-sperm. The fluorescently stained sperm are then sex-sorted using a specialized high speed sorter, MoFlo(®) SX XDP, and collected into biologically supportive media prior to reconcentration and cryopreservation in numbers adequate for use with artificial insemination for some species or for in vitro fertilization. Sperm sorting can provide subpopulations of X- or Y-bearing bovine sperm at rates in the 8,000 sperm/s range while maintaining; a purity of 90% such that it has been applied to cattle on a commercial basis. The sex of offspring has been predetermined in a wide variety of mammalian species including cattle, swine, horses, sheep, goats, dogs, cats, deer, elk, dolphins, water buffalo as well as in humans using flow cytometric sorting of X- and Y-sperm.

Particles Sorting in Micro Channel Using Designed Micro Electromagnets of Magnetic Field Gradient

International Nuclear Information System (INIS)

Chung, Yung-Chiang; Wu, Chen-Ming; Lin, Shih-Hao

2016-01-01

In this study, microelectromagnet, microchannel, syringe pump, and controlling devices were integrated to form a particle sorting system. A simple, two-dimensional, relatively quick fabricating and easily operating microelectromagnet was designed. Polystyrene particles and magnetic beads were pumped into the microchannel with the syringe pump, and it was observed that the magnetic beads were attracted to one of two outlets by the microelectromagnet, which features a gradually changing magnetic field. The polystyrene particles would move to another outlet because of different-width micro channel, and it completed the separation of the particles. Based on experimental results, the magnetic flux density of the microelectromagnet was 2.3 Gauss for a 12.5-μm average distance between electrodes at 1.0-μm increments, and the magnetic force was 0.22 pN for 2.8-μm magnetic beads. The separating rate was greater for larger distance increment and smaller average distance between the electrodes. The separating rate of the magnetic beads increased as the electric current increased and flow velocity decreased. When the flow velocity was 0.333 μm/s and electric current was 1 A, the separating rate was 90%. The separating rate of the polystyrene particles increased as the flow velocity increased and was 85% when the flow velocity was 0.6 μm/s. These results demonstrate that this particle sorting system has potential applications in bio-molecular studies. - Highlights: • We proposed a method for separating polystyrene particles and magnetic beads by the different-width outlets and microelectromagnet with gradually changing magnetic field, which is simple, two-dimensional and easily operating. • The separating rate was greater for larger distance increment and smaller average distance between the electrodes. • The separating rate of the magnetic beads increased as the electric current increased and flow velocity decreased, and the maximum value is 90%.

The ROCK inhibitor Y-27632 improves recovery of human embryonic stem cells after fluorescence-activated cell sorting with multiple cell surface markers.

Directory of Open Access Journals (Sweden)

Nil Emre

Full Text Available BACKGROUND: Due to the inherent sensitivity of human embryonic stem cells (hESCs to manipulations, the recovery and survival of hESCs after fluorescence-activated cell sorting (FACS can be low. Additionally, a well characterized and robust methodology for performing FACS on hESCs using multiple-cell surface markers has not been described. The p160-Rho-associated coiled kinase (ROCK inhibitor, Y-27632, previously has been identified as enhancing survival of hESCs upon single-cell dissociation, as well as enhancing recovery from cryopreservation. Here we examined the application of Y-27632 to hESCs after FACS to improve survival in both feeder-dependent and feeder-independent growth conditions. METHODOLOGY/PRINCIPAL FINDINGS: HESCs were sorted using markers for SSEA-3, TRA-1-81, and SSEA-1. Cells were plated after sorting for 24 hours in either the presence or the absence of Y-27632. In both feeder-dependent and feeder-independent conditions, cell survival was greater when Y-27632 was applied to the hESCs after sort. Specifically, treatment of cells with Y-27632 improved post-sort recovery up to four fold. To determine the long-term effects of sorting with and without the application of Y-27632, hESCs were further analyzed. Specifically, hESCs sorted with and without the addition of Y-27632 retained normal morphology, expressed hESC-specific markers as measured by immunocytochemistry and flow cytometry, and maintained a stable karyotype. In addition, the hESCs could differentiate into three germ layers in vitro and in vivo in both feeder-dependent and feeder-independent growth conditions. CONCLUSIONS/SIGNIFICANCE: The application of Y-27632 to hESCs after cell sorting improves cell recovery with no observed effect on pluripotency, and enables the consistent recovery of hESCs by FACS using multiple surface markers. This improved methodology for cell sorting of hESCs will aid many applications such as removal of hESCs from secondary cell types

Optical cell sorting with multiple imaging modalities

DEFF Research Database (Denmark)

Banas, Andrew; Carrissemoux, Caro; Palima, Darwin

2017-01-01

healthy cells. With the richness of visual information, a lot of microscopy techniques have been developed and have been crucial in biological studies. To utilize their complementary advantages we adopt both fluorescence and brightfield imaging in our optical cell sorter. Brightfield imaging has...... the advantage of being non-invasive, thus maintaining cell viability. Fluorescence imaging, on the other hand, takes advantages of the chemical specificity of fluorescence markers and can validate machine vision results from brightfield images. Visually identified cells are sorted using optical manipulation...

International Society for Analytical Cytology biosafety standard for sorting of unfixed cells.

Science.gov (United States)

Schmid, Ingrid; Lambert, Claude; Ambrozak, David; Marti, Gerald E; Moss, Delynn M; Perfetto, Stephen P

2007-06-01

Cell sorting of viable biological specimens has become very prevalent in laboratories involved in basic and clinical research. As these samples can contain infectious agents, precautions to protect instrument operators and the environment from hazards arising from the use of sorters are paramount. To this end the International Society of Analytical Cytology (ISAC) took a lead in establishing biosafety guidelines for sorting of unfixed cells (Schmid et al., Cytometry 1997;28:99-117). During the time period these recommendations have been available, they have become recognized worldwide as the standard practices and safety precautions for laboratories performing viable cell sorting experiments. However, the field of cytometry has progressed since 1997, and the document requires an update. Initially, suggestions about the document format and content were discussed among members of the ISAC Biosafety Committee and were incorporated into a draft version that was sent to all committee members for review. Comments were collected, carefully considered, and incorporated as appropriate into a draft document that was posted on the ISAC web site to invite comments from the flow cytometry community at large. The revised document was then submitted to ISAC Council for review. Simultaneously, further comments were sought from newly-appointed ISAC Biosafety committee members. This safety standard for performing viable cell sorting experiments was recently generated. The document contains background information on the biohazard potential of sorting and the hazard classification of infectious agents as well as recommendations on (1) sample handling, (2) operator training and personal protection, (3) laboratory design, (4) cell sorter set-up, maintenance, and decontamination, and (5) testing the instrument for the efficiency of aerosol containment. This standard constitutes an updated and expanded revision of the 1997 biosafety guideline document. It is intended to provide

Raman-Activated Droplet Sorting (RADS) for Label-Free High-Throughput Screening of Microalgal Single-Cells.

Science.gov (United States)

Wang, Xixian; Ren, Lihui; Su, Yetian; Ji, Yuetong; Liu, Yaoping; Li, Chunyu; Li, Xunrong; Zhang, Yi; Wang, Wei; Hu, Qiang; Han, Danxiang; Xu, Jian; Ma, Bo

2017-11-21

Raman-activated cell sorting (RACS) has attracted increasing interest, yet throughput remains one major factor limiting its broader application. Here we present an integrated Raman-activated droplet sorting (RADS) microfluidic system for functional screening of live cells in a label-free and high-throughput manner, by employing AXT-synthetic industrial microalga Haematococcus pluvialis (H. pluvialis) as a model. Raman microspectroscopy analysis of individual cells is carried out prior to their microdroplet encapsulation, which is then directly coupled to DEP-based droplet sorting. To validate the system, H. pluvialis cells containing different levels of AXT were mixed and underwent RADS. Those AXT-hyperproducing cells were sorted with an accuracy of 98.3%, an enrichment ratio of eight folds, and a throughput of ∼260 cells/min. Of the RADS-sorted cells, 92.7% remained alive and able to proliferate, which is equivalent to the unsorted cells. Thus, the RADS achieves a much higher throughput than existing RACS systems, preserves the vitality of cells, and facilitates seamless coupling with downstream manipulations such as single-cell sequencing and cultivation.

Optimization of magnetic switches for single particle and cell transport

Energy Technology Data Exchange (ETDEWEB)

Abedini-Nassab, Roozbeh; Yellen, Benjamin B., E-mail: yellen@duke.edu [Department of Mechanical Engineering and Materials Science, Duke University, Box 90300 Hudson Hall, Durham, North Carolina 27708 (United States); Joint Institute, University of Michigan—Shanghai Jiao Tong University, Shanghai Jiao Tong University, Shanghai 200240 (China); Murdoch, David M. [Department of Medicine, Duke University, Durham, North Carolina 27708 (United States); Kim, CheolGi [Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873 (Korea, Republic of)

2014-06-28

The ability to manipulate an ensemble of single particles and cells is a key aim of lab-on-a-chip research; however, the control mechanisms must be optimized for minimal power consumption to enable future large-scale implementation. Recently, we demonstrated a matter transport platform, which uses overlaid patterns of magnetic films and metallic current lines to control magnetic particles and magnetic-nanoparticle-labeled cells; however, we have made no prior attempts to optimize the device geometry and power consumption. Here, we provide an optimization analysis of particle-switching devices based on stochastic variation in the particle's size and magnetic content. These results are immediately applicable to the design of robust, multiplexed platforms capable of transporting, sorting, and storing single cells in large arrays with low power and high efficiency.

Raman tweezers in microfluidic systems for analysis and sorting of living cells

Science.gov (United States)

Pilát, Zdeněk.; Ježek, Jan; Kaňka, Jan; Zemánek, Pavel

2014-12-01

We have devised an analytical and sorting system combining optical trapping with Raman spectroscopy in microfluidic environment, dedicated to identification and sorting of biological objects, such as living cells of various unicellular organisms. Our main goal was to create a robust and universal platform for non-destructive and non-contact sorting of micro-objects based on their Raman spectral properties. This approach allowed us to collect spectra containing information about the chemical composition of the objects, such as the presence and composition of pigments, lipids, proteins, or nucleic acids, avoiding artificial chemical probes such as fluorescent markers. The non-destructive nature of this optical analysis and manipulation allowed us to separate individual living cells of our interest in a sterile environment and provided the possibility to cultivate the selected cells for further experiments. We used a mixture of polystyrene micro-particles and algal cells to test and demonstrate the function of our analytical and sorting system. The devised system could find its use in many medical, biotechnological, and biological applications.

Sorting cells of the microalga Chlorococcum littorale with increased triacylglycerol productivity.

Science.gov (United States)

Cabanelas, Iago Teles Dominguez; van der Zwart, Mathijs; Kleinegris, Dorinde M M; Wijffels, René H; Barbosa, Maria J

2016-01-01

Despite extensive research in the last decades, microalgae are still only economically feasible for high valued markets. Strain improvement is a strategy to increase productivities, hence reducing costs. In this work, we focus on microalgae selection: taking advantage of the natural biological variability of species to select variations based on desired characteristics. We focused on triacylglycerol (TAG), which have applications ranging from biodiesel to high-value omega-3 fatty-acids. Hence, we demonstrated a strategy to sort microalgae cells with increased TAG productivity. 1. We successfully identified sub-populations of cells with increased TAG productivity using Fluorescence assisted cell sorting (FACS). 2. We sequentially sorted cells after repeated cycles of N-starvation, resulting in five sorted populations (S1-S5). 3. The comparison between sorted and original populations showed that S5 had the highest TAG productivity [0.34 against 0.18 g l(-1) day(-1) (original), continuous light]. 4. Original and S5 were compared in lab-scale reactors under simulated summer conditions confirming the increased TAG productivity of S5 (0.4 against 0.2 g l(-1) day(-1)). Biomass composition analyses showed that S5 produced more biomass under N-starvation because of an increase only in TAG content and, flow cytometry showed that our selection removed cells with lower efficiency in producing TAGs. All combined, our results present a successful strategy to improve the TAG productivity of Chlorococcum littorale, without resourcing to genetic manipulation or random mutagenesis. Additionally, the improved TAG productivity of S5 was confirmed under simulated summer conditions, highlighting the industrial potential of S5 for microalgal TAG production.

IB-LBM simulation on blood cell sorting with a micro-fence structure.

Science.gov (United States)

Wei, Qiang; Xu, Yuan-Qing; Tian, Fang-bao; Gao, Tian-xin; Tang, Xiao-ying; Zu, Wen-Hong

2014-01-01

A size-based blood cell sorting model with a micro-fence structure is proposed in the frame of immersed boundary and lattice Boltzmann method (IB-LBM). The fluid dynamics is obtained by solving the discrete lattice Boltzmann equation, and the cells motion and deformation are handled by the immersed boundary method. A micro-fence consists of two parallel slope post rows which are adopted to separate red blood cells (RBCs) from white blood cells (WBCs), in which the cells to be separated are transported one after another by the flow into the passageway between the two post rows. Effected by the cross flow, RBCs are schemed to get through the pores of the nether post row since they are smaller and more deformable compared with WBCs. WBCs are required to move along the nether post row till they get out the micro-fence. Simulation results indicate that for a fix width of pores, the slope angle of the post row plays an important role in cell sorting. The cells mixture can not be separated properly in a small slope angle, while obvious blockages by WBCs will take place to disturb the continuous cell sorting in a big slope angle. As an optimal result, an adaptive slope angle is found to sort RBCs form WBCs correctly and continuously.

Cell flux through S phase in the mouse duodenal epithelium determined by cell sorting and radioautography

International Nuclear Information System (INIS)

Bjerknes, M.; Cheng, H.

1982-01-01

An accumulation of cells in early S phase was observed in normal mouse duodenal epithelium studied with flow cytometry. To determine if this accumulation of cells was the result of a lower rate of DNA synthesis, animals were given a single injection of 3 H-thymidine and the epithelium collected one hour later. The epithelium was processed for flow cytometry. Seven sort windows were established in different portions of the DNA histogram. Cells from each window were sorted onto glass slides that were then processed for radioautography. The number of silver grains over the nuclei of each sorted population was counted. It was found that cells in early S phase had significantly fewer grains over their nuclei than did mid- or late-S phase cells. We conclude that the accumulation of cells in early S phase is due, at least in part, to a lower rate of DNA synthesis in early than in mid or late S phase

Flow sorting in aquatic ecology

Directory of Open Access Journals (Sweden)

Marcus Reckermann

2000-06-01

Full Text Available Flow sorting can be a very helpful tool in revealing phytoplankton and bacterial community structure and elaborating specific physiological parameters of isolated species. Droplet sorting has been the most common technique. Despite the high optical and hydro-dynamic stress for the cells to be sorted, many species grow in culture subsequent to sorting. To date, flow sorting has been applied to post-incubation separation in natural water samples to account for group-specific physiological parameters (radiotracer-uptake rates, to the production of clonal or non-clonal cultures from mixtures, to the isolaton of cell groups from natural assemblages for molecular analyses, and for taxonomic identification of sorted cells by microscopy. The application of cell sorting from natural water samples from the Wadden Sea, including different cryptophytes, cyanobacteria and diatoms, is shown, as well as the establishment of laboratory cultures from field samples. The optional use of a red laser to account for phycocyanine-rich cells is also discussed.

Size-based cell sorting with a resistive pulse sensor and an electromagnetic pump in a microfluidic chip.

Science.gov (United States)

Song, Yongxin; Li, Mengqi; Pan, Xinxiang; Wang, Qi; Li, Dongqing

2015-02-01

An electrokinetic microfluidic chip is developed to detect and sort target cells by size from human blood samples. Target-cell detection is achieved by a differential resistive pulse sensor (RPS) based on the size difference between the target cell and other cells. Once a target cell is detected, the detected RPS signal will automatically actuate an electromagnetic pump built in a microchannel to push the target cell into a collecting channel. This method was applied to automatically detect and sort A549 cells and T-lymphocytes from a peripheral fingertip blood sample. The viability of A549 cells sorted in the collecting well was verified by Hoechst33342 and propidium iodide staining. The results show that as many as 100 target cells per minute can be sorted out from the sample solution and thus is particularly suitable for sorting very rare target cells, such as circulating tumor cells. The actuation of the electromagnetic valve has no influence on RPS cell detection and the consequent cell-sorting process. The viability of the collected A549 cell is not impacted by the applied electric field when the cell passes the RPS detection area. The device described in this article is simple, automatic, and label-free and has wide applications in size-based rare target cell sorting for medical diagnostics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Safe sorting of GFP-transduced live cells for subsequent culture using a modified FACS vantage

DEFF Research Database (Denmark)

Sørensen, T U; Gram, G J; Nielsen, S D

1999-01-01

BACKGROUND: A stream-in-air cell sorter enables rapid sorting to a high purity, but it is not well suited for sorting of infectious material due to the risk of airborne spread to the surroundings. METHODS: A FACS Vantage cell sorter was modified for safe use with potentially HIV infected cells...... culture. CONCLUSIONS: Sorting of live infected cells can be performed safely and with no deleterious effects on vector expression using the modified FACS Vantage instrument....

A simple model based magnet sorting algorithm for planar hybrid undulators

International Nuclear Information System (INIS)

Rakowsky, G.

2010-01-01

Various magnet sorting strategies have been used to optimize undulator performance, ranging from intuitive pairing of high- and low-strength magnets, to full 3D FEM simulation with 3-axis Helmholtz coil magnet data. In the extreme, swapping magnets in a full field model to minimize trajectory wander and rms phase error can be time consuming. This paper presents a simpler approach, extending the field error signature concept to obtain trajectory displacement, kick angle and phase error signatures for each component of magnetization error from a Radia model of a short hybrid-PM undulator. We demonstrate that steering errors and phase errors are essentially decoupled and scalable from measured X, Y and Z components of magnetization. Then, for any given sequence of magnets, rms trajectory and phase errors are obtained from simple cumulative sums of the scaled displacements and phase errors. The cost function (a weighted sum of these errors) is then minimized by swapping magnets, using one's favorite optimization algorithm. This approach was applied recently at NSLS to a short in-vacuum undulator, which required no subsequent trajectory or phase shimming. Trajectory and phase signatures are also obtained for some mechanical errors, to guide 'virtual shimming' and specifying mechanical tolerances. Some simple inhomogeneities are modeled to assess their error contributions.

A multiple objective magnet sorting algorithm for the Advanced Light Source insertion devices

International Nuclear Information System (INIS)

Humphries, D.; Goetz, F.; Kownacki, P.; Marks, S.; Schlueter, R.

1995-01-01

Insertion devices for the Advanced Light Source (ALS) incorporate large numbers of permanent magnets which have a variety of magnetization orientation errors. These orientation errors can produce field errors which affect both the spectral brightness of the insertion devices and the storage ring electron beam dynamics. A perturbation study was carried out to quantify the effects of orientation errors acting in a hybrid magnetic structure. The results of this study were used to develop a multiple stage sorting algorithm which minimizes undesirable integrated field errors and essentially eliminates pole excitation errors. When applied to a measured magnet population for an existing insertion device, an order of magnitude reduction in integrated field errors was achieved while maintaining near zero pole excitation errors

How to develop a Standard Operating Procedure for sorting unfixed cells

Science.gov (United States)

Schmid, Ingrid

2012-01-01

Written Standard Operating Procedures (SOPs) are an important tool to assure that recurring tasks in a laboratory are performed in a consistent manner. When the procedure covered in the SOP involves a high-risk activity such as sorting unfixed cells using a jet-in-air sorter, safety elements are critical components of the document. The details on sort sample handling, sorter set-up, validation, operation, troubleshooting, and maintenance, personal protective equipment (PPE), and operator training, outlined in the SOP are to be based on careful risk assessment of the procedure. This review provides background information on the hazards associated with sorting of unfixed cells and the process used to arrive at the appropriate combination of facility design, instrument placement, safety equipment, and practices to be followed. PMID:22381383

How to develop a standard operating procedure for sorting unfixed cells.

Science.gov (United States)

Schmid, Ingrid

2012-07-01

Written standard operating procedures (SOPs) are an important tool to assure that recurring tasks in a laboratory are performed in a consistent manner. When the procedure covered in the SOP involves a high-risk activity such as sorting unfixed cells using a jet-in-air sorter, safety elements are critical components of the document. The details on sort sample handling, sorter set-up, validation, operation, troubleshooting, and maintenance, personal protective equipment (PPE), and operator training, outlined in the SOP are to be based on careful risk assessment of the procedure. This review provides background information on the hazards associated with sorting of unfixed cells and the process used to arrive at the appropriate combination of facility design, instrument placement, safety equipment, and practices to be followed. Copyright © 2012 Elsevier Inc. All rights reserved.

N-Glycosylation instead of cholesterol mediates oligomerization and apical sorting of GPI-APs in FRT cells.

Science.gov (United States)

Imjeti, Naga Salaija; Lebreton, Stéphanie; Paladino, Simona; de la Fuente, Erwin; Gonzalez, Alfonso; Zurzolo, Chiara

2011-12-01

Sorting of glycosylphosphatidyl-inositol--anchored proteins (GPI-APs) in polarized epithelial cells is not fully understood. Oligomerization in the Golgi complex has emerged as the crucial event driving apical segregation of GPI-APs in two different kind of epithelial cells, Madin-Darby canine kidney (MDCK) and Fisher rat thyroid (FRT) cells, but whether the mechanism is conserved is unknown. In MDCK cells cholesterol promotes GPI-AP oligomerization, as well as apical sorting of GPI-APs. Here we show that FRT cells lack this cholesterol-driven oligomerization as apical sorting mechanism. In these cells both apical and basolateral GPI-APs display restricted diffusion in the Golgi likely due to a cholesterol-enriched membrane environment. It is striking that N-glycosylation is the critical event for oligomerization and apical sorting of GPI-APs in FRT cells but not in MDCK cells. Our data indicate that at least two mechanisms exist to determine oligomerization in the Golgi leading to apical sorting of GPI-APs. One depends on cholesterol, and the other depends on N-glycosylation and is insensitive to cholesterol addition or depletion.

Magnetic manipulation of particles and cells in ferrofluid flow through straight microchannels using two magnets

Science.gov (United States)

Zeng, Jian

Microfluidic devices have been increasingly used in the past two decades for particle and cell manipulations in many chemical and biomedical applications. A variety of force fields have been demonstrated to control particle and cell transport in these devices including electric, magnetic, acoustic, and optical forces etc. Among these particle handling techniques, the magnetic approach provides clear advantages over others such as low cost, noninvasive, and free of fluid heating issues. However, the current knowledge of magnetic control of particle transport is still very limited, especially lacking is the handling of diamagnetic particle. This thesis is focused on the magnetic manipulation of diamagnetic particles and cells in ferrofluid flow through the use of a pair of permanent magnets. By varying the configuration of the two magnets, diverse operations of particles and cells is implemented in a straight microchannel that can potentially be integrated into lab-on-a-chip devices for various applications. First, an approach for embedding two, symmetrically positioned, repulsive permanent magnets about a straight rectangular microchannel in a PDMS-based microfluidic device is developed for particle focusing. Focusing particles and cells into a tight stream is often required in order for continuous detection, counting, and sorting. The closest distance between the magnets is limited only by the size of the magnets involved in the fabrication process. The device is used to implement and investigate the three-dimensional magnetic focusing of polystyrene particles in ferrofluid microflow with both top-view and side-view visualizations. The effects of flow speed and particle size on the particle focusing effectiveness are studied. This device is also applied to magnetically focus yeast cells in ferrofluid, which proves to be biocompatible as verified by cell viability test. In addition, an analytical model is developed and found to be able to predict the experimentally

A monolithic glass chip for active single-cell sorting based on mechanical phenotyping.

Science.gov (United States)

Faigle, Christoph; Lautenschläger, Franziska; Whyte, Graeme; Homewood, Philip; Martín-Badosa, Estela; Guck, Jochen

2015-03-07

The mechanical properties of biological cells have long been considered as inherent markers of biological function and disease. However, the screening and active sorting of heterogeneous populations based on serial single-cell mechanical measurements has not been demonstrated. Here we present a novel monolithic glass chip for combined fluorescence detection and mechanical phenotyping using an optical stretcher. A new design and manufacturing process, involving the bonding of two asymmetrically etched glass plates, combines exact optical fiber alignment, low laser damage threshold and high imaging quality with the possibility of several microfluidic inlet and outlet channels. We show the utility of such a custom-built optical stretcher glass chip by measuring and sorting single cells in a heterogeneous population based on their different mechanical properties and verify sorting accuracy by simultaneous fluorescence detection. This offers new possibilities of exact characterization and sorting of small populations based on rheological properties for biological and biomedical applications.

Culture of somatic cells isolated from frozen-thawed equine semen using fluorescence-assisted cell sorting.

Science.gov (United States)

Brom-de-Luna, Joao Gatto; Canesin, Heloísa Siqueira; Wright, Gus; Hinrichs, Katrin

2018-03-01

Nuclear transfer using somatic cells from frozen semen (FzSC) would allow cloning of animals for which no other genetic material is available. Horses are one of the few species for which cloning is commercially feasible; despite this, there is no information available on the culture of equine FzSC. After preliminary trials on equine FzSC, recovered by density-gradient centrifugation, resulted in no growth, we hypothesized that sperm in the culture system negatively affected cell proliferation. Therefore, we evaluated culture of FzSC isolated using fluorescence-assisted cell sorting. In Exp. 1, sperm were labeled using antibodies to a sperm-specific antigen, SP17, and unlabeled cells were collected. This resulted in high sperm contamination. In Exp. 2, FzSC were labeled using an anti-MHC class I antibody. This resulted in an essentially pure population of FzSC, 13-25% of which were nucleated. Culture yielded no proliferation in any of nine replicates. In Exp. 3, 5 × 10 3 viable fresh, cultured horse fibroblasts were added to the frozen-thawed, washed semen, then this suspension was labeled and sorted as for Exp. 2. The enriched population had a mean of five sperm per recovered somatic cell; culture yielded formation of monolayers. In conclusion, an essentially pure population of equine FzSC could be obtained using sorting for presence of MHC class I antigens. No equine FzSC grew in culture; however, the proliferation of fibroblasts subjected to the same processing demonstrated that the labeling and sorting methods, and the presence of few sperm in culture, were compatible with cell viability. Copyright © 2017 Elsevier B.V. All rights reserved.

Using pico-LCoS SLMs for high speed cell sorting

DEFF Research Database (Denmark)

Bañas, Andrew Rafael; Aabo, Thomas; Palima, Darwin

2012-01-01

We propose the use of consumer pico projectors as cost effective spatial light modulators in cell sorting applications. The matched filtering Generalized Phase Contrast (mGPC) beam shaping method is used to produce high intensity optical spots for trapping and catapulting cells. A pico projector......’s liquid crystal on silicon (LCoS) chip was used as a binary phase spatial light modulator (SLM) wherein correlation target patterns are addressed. Experiments using the binary LCoS phase SLM with a fabricated Pyrex matched filter demonstrate the generation of intense optical spots that can potentially...... be used for cell sorting. Numerical studies also show mGPC’s robustness to phase aberrations in the LCoS device, and its ability to outperform a top hat beam with the same power....

External parallel sorting with multiprocessor computers

International Nuclear Information System (INIS)

Comanceau, S.I.

1984-01-01

This article describes methods of external sorting in which the entire main computer memory is used for the internal sorting of entries, forming out of them sorted segments of the greatest possible size, and outputting them to external memories. The obtained segments are merged into larger segments until all entries form one ordered segment. The described methods are suitable for sequential files stored on magnetic tape. The needs of the sorting algorithm can be met by using the relatively slow peripheral storage devices (e.g., tapes, disks, drums). The efficiency of the external sorting methods is determined by calculating the total sorting time as a function of the number of entries to be sorted and the number of parallel processors participating in the sorting process

Microfluidic-chip platform for cell sorting

Science.gov (United States)

Malik, Sarul; Balyan, Prerna; Akhtar, J.; Agarwal, Ajay

2016-04-01

Cell sorting and separation are considered to be very crucial preparatory steps for numerous clinical diagnostics and therapeutics applications in cell biology research arena. Label free cell separation techniques acceptance rate has been increased to multifold by various research groups. Size based cell separation method focuses on the intrinsic properties of the cell which not only avoids clogging issues associated with mechanical and centrifugation filtration methods but also reduces the overall cost for the process. Consequentially flow based cell separation method for continuous flow has attracted the attention of millions. Due to the realization of structures close to particle size in micro dimensions, the microfluidic devices offer precise and rapid particle manipulation which ultimately leads to an extraordinary cell separation results. The proposed microfluidic device is fabricated to separate polystyrene beads of size 1 µm, 5 µm, 10 µm and 20 µm. The actual dimensions of blood corpuscles were kept in mind while deciding the particle size of polystyrene beads which are used as a model particles for study.

High-throughput microfluidic mixing and multiparametric cell sorting for bioactive compound screening.

Science.gov (United States)

Young, Susan M; Curry, Mark S; Ransom, John T; Ballesteros, Juan A; Prossnitz, Eric R; Sklar, Larry A; Edwards, Bruce S

2004-03-01

HyperCyt, an automated sample handling system for flow cytometry that uses air bubbles to separate samples sequentially introduced from multiwell plates by an autosampler. In a previously documented HyperCyt configuration, air bubble separated compounds in one sample line and a continuous stream of cells in another are mixed in-line for serial flow cytometric cell response analysis. To expand capabilities for high-throughput bioactive compound screening, the authors investigated using this system configuration in combination with automated cell sorting. Peptide ligands were sampled from a 96-well plate, mixed in-line with fluo-4-loaded, formyl peptide receptor-transfected U937 cells, and screened at a rate of 3 peptide reactions per minute with approximately 10,000 cells analyzed per reaction. Cell Ca(2+) responses were detected to as little as 10(-11) M peptide with no detectable carryover between samples at up to 10(-7) M peptide. After expansion in culture, cells sort-purified from the 10% highest responders exhibited enhanced sensitivity and more sustained responses to peptide. Thus, a highly responsive cell subset was isolated under high-throughput mixing and sorting conditions in which response detection capability spanned a 1000-fold range of peptide concentration. With single-cell readout systems for protein expression libraries, this technology offers the promise of screening millions of discrete compound interactions per day.

Machine-vision based optofluidic cell sorting

DEFF Research Database (Denmark)

Glückstad, Jesper; Bañas, Andrew

the available light and creating 2D or 3D beam distributions aimed at the positions of the detected cells. Furthermore, the beam shaping freedom provided by GPC can allow optimizations in the beam’s propagation and its interaction with the laser catapulted and sorted cells....... machine vision1. This approach is gentler, less invasive and more economical compared to conventional FACS-systems. As cells are less responsive to plastic or glass objects commonly used in the optical manipulation literature2, and since laser safety would be an issue in clinical use, we develop efficient...... approaches in utilizing lasers and light modulation devices. The Generalized Phase Contrast (GPC) method3-9 that can be used for efficiently illuminating spatial light modulators10 or creating well-defined contiguous optical traps11 is supplemented by diffractive techniques capable of integrating...

Isolation of Human Induced Pluripotent Stem Cell-Derived Dopaminergic Progenitors by Cell Sorting for Successful Transplantation

Directory of Open Access Journals (Sweden)

Daisuke Doi

2014-03-01

Full Text Available Human induced pluripotent stem cells (iPSCs can provide a promising source of midbrain dopaminergic (DA neurons for cell replacement therapy for Parkinson’s disease. However, iPSC-derived donor cells inevitably contain tumorigenic or inappropriate cells. Here, we show that human iPSC-derived DA progenitor cells can be efficiently isolated by cell sorting using a floor plate marker, CORIN. We induced DA neurons using scalable culture conditions on human laminin fragment, and the sorted CORIN+ cells expressed the midbrain DA progenitor markers, FOXA2 and LMX1A. When transplanted into 6-OHDA-lesioned rats, the CORIN+ cells survived and differentiated into midbrain DA neurons in vivo, resulting in significant improvement of the motor behavior, without tumor formation. In particular, the CORIN+ cells in a NURR1+ cell-dominant stage exhibited the best survival and function as DA neurons. Our method is a favorable strategy in terms of scalability, safety, and efficiency and may be advantageous for clinical application.

Improved method and apparatus for electrostatically sorting biological cells. [DOE patent application

Science.gov (United States)

Merrill, J.T.

An improved method of sorting biological cells in a conventional cell sorter apparatus includes generating a fluid jet containing cells to be sorted, measuring the distance between the centers of adjacent droplets in a zone thereof defined at the point where the fluid jet separates into descrete droplets, setting the distance between the center of a droplet in said separation zone and the position along said fluid jet at which the cell is optically sensed for specific characteristics to be an integral multiple of said center-to-center distance, and disabling a charger from electrically charging a specific droplet if a cell is detected by the optical sensor in a position wherein it will be in the neck area between droplets during droplet formation rather than within a predetermined distance from the droplet center.

Numerical study on the complete blood cell sorting using particle tracing and dielectrophoresis in a microfluidic device

Science.gov (United States)

Ali, Haider; Park, Cheol Woo

2016-11-01

In this study, a numerical model of a microfluidic device with particle tracing and dielectrophoresis field-flow fractionation was employed to perform a complete and continuous blood cell sorting. A low voltage was applied to electrodes to separate the red blood cells, white blood cells, and platelets based on their cell size. Blood cell sorting and counting were performed by evaluating the cell trajectories, displacements, residence times, and recovery rates in the device. A novel numerical technique was used to count the number of separated blood cells by estimating the displacement and residence time of the cells in a microfluidic device. For successful blood cell sorting, the value of cells displacement must be approximately equal to or higher than the corresponding maximum streamwise distance. The study also proposed different outlet designs to improve blood cell separation. The basic outlet design resulted in a higher cells recovery rate than the other outlets design. The recovery rate decreased as the number of inlet cells and flow rates increased because of the high particle-particle interactions and collisions with walls. The particle-particle interactions significantly affect blood cell sorting and must therefore be considered in future work.

Magnetic manipulation device for the optimization of cell processing conditions.

Science.gov (United States)

Ito, Hiroshi; Kato, Ryuji; Ino, Kosuke; Honda, Hiroyuki

2010-02-01

Variability in human cell phenotypes make it's advancements in optimized cell processing necessary for personalized cell therapy. Here we propose a strategy of palm-top sized device to assist physically manipulating cells for optimizing cell preparations. For the design of such a device, we combined two conventional approaches: multi-well plate formatting and magnetic cell handling using magnetite cationic liposomes (MCLs). From our previous works, we showed the labeling applications of MCL on adhesive cells for various tissue engineering approaches. To feasibly transfer cells in multi-well plate, we here evaluated the magnetic response of MCL-labeled suspension type cells. The cell handling performance of Jurkat cells proved to be faster and more robust compared to MACS (Magnetic Cell Sorting) bead methods. To further confirm our strategy, prototype palm-top sized device "magnetic manipulation device (MMD)" was designed. In the device, the actual cell transportation efficacy of Jurkat cells was satisfying. Moreover, as a model of the most distributed clinical cell processing, primary peripheral blood mononuclear cells (PBMCs) from different volunteers were evaluated. By MMD, individual PBMCs indicated to have optimum Interleukin-2 (IL-2) concentrations for the expansion. Such huge differences of individual cells indicated that MMD, our proposing efficient and self-contained support tool, could assist the feasible and cost-effective optimization of cell processing in clinical facilities. Copyright (c) 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Isolation of intact RNA from murine CD4+ T cells after intracellular cytokine staining and fluorescence-activated cell sorting.

Science.gov (United States)

Kunnath-Velayudhan, Shajo; Porcelli, Steven A

2018-05-01

Intracellular cytokine staining (ICS) is a powerful method for identifying functionally distinct lymphocyte subsets, and for isolating these by fluorescence activated cell sorting (FACS). Although transcriptomic analysis of cells sorted on the basis of ICS has many potential applications, this is rarely performed because of the difficulty in isolating intact RNA from cells processed using standard fixation and permeabilization buffers for ICS. To address this issue, we compared three buffers shown previously to preserve RNA in nonhematopoietic cells subjected to intracellular staining for their effects on RNA isolated from T lymphocytes processed for ICS. Our results showed that buffers containing the recombinant ribonuclease inhibitor RNasin or high molar concentrations of salt yielded intact RNA from fixed and permeabilized T cells. As proof of principle, we successfully used the buffer containing RNasin to isolate intact RNA from CD4 + T cells that were sorted by FACS on the basis of specific cytokine production, thus demonstrating the potential of this approach for coupling ICS with transcriptomic analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

On-chip Magnetic Separation and Cell Encapsulation in Droplets

Science.gov (United States)

Chen, A.; Byvank, T.; Bharde, A.; Miller, B. L.; Chalmers, J. J.; Sooryakumar, R.; Chang, W.-J.; Bashir, R.

2012-02-01

The demand for high-throughput single cell assays is gaining importance because of the heterogeneity of many cell suspensions, even after significant initial sorting. These suspensions may display cell-to-cell variability at the gene expression level that could impact single cell functional genomics, cancer, stem-cell research and drug screening. The on-chip monitoring of individual cells in an isolated environment could prevent cross-contamination, provide high recovery yield and ability to study biological traits at a single cell level These advantages of on-chip biological experiments contrast to conventional methods, which require bulk samples that provide only averaged information on cell metabolism. We report on a device that integrates microfluidic technology with a magnetic tweezers array to combine the functionality of separation and encapsulation of objects such as immunomagnetically labeled cells or magnetic beads into pico-liter droplets on the same chip. The ability to control the separation throughput that is independent of the hydrodynamic droplet generation rate allows the encapsulation efficiency to be optimized. The device can potentially be integrated with on-chip labeling and/or bio-detection to become a powerful single-cell analysis device.

Postendocytic sorting of constitutively internalized dopamine transporter in cell lines and dopaminergic neurons

DEFF Research Database (Denmark)

Eriksen, Jacob; Bjørn-Yoshimoto, Walden Emil; Jørgensen, Trine Nygaard

2010-01-01

The dopamine transporter (DAT) mediates reuptake of released dopamine and is the target for psychostimulants, such as cocaine and amphetamine. DAT undergoes marked constitutive endocytosis, but little is known about the fate and sorting of the endocytosed transporter. To study DAT sorting in cells...... lines, we fused the one-transmembrane segment protein Tac to DAT, thereby generating a transporter (TacDAT) with an extracellular antibody epitope suited for trafficking studies. TacDAT was functional and endocytosed constitutively in HEK293 cells. According to an ELISA-based assay, TacDAT intracellular...

Magnethophoretic sorting of fluid catalytic cracking particles

NARCIS (Netherlands)

Solsona, Miguel; Nieuwelink, A. E.; Odijk, Mathieu; Meirer, Florian; Abelmann, Leon; Olthuis, Wouter; Weckhuysen, Bert M.; van den Berg, Albert; Lee, Abraham; DeVoe, Don

2017-01-01

We demonstrate an on-chip particle activity sorter, focused on iron concentration and based on magnetophoresis. This device was used for fast sorting of stepwise homogenously distributed [Fe]s. The preliminary results are very encouraging. We show that we can sort particles on magnetic moment, with

Magnetic Nickel iron Electroformed Trap (MagNET): a master/replica fabrication strategy for ultra-high throughput (>100 mL h−1) immunomagnetic sorting†

Science.gov (United States)

Ko, Jina; Yelleswarapu, Venkata; Singh, Anup; Shah, Nishal

2016-01-01

Microfluidic devices can sort immunomagnetically labeled cells with sensitivity and specificity much greater than that of conventional methods, primarily because the size of microfluidic channels and micro-scale magnets can be matched to that of individual cells. However, these small feature sizes come at the expense of limited throughput (ϕ 10 mL whole blood. Here, we report a new approach to micromagnetic sorting that can achieve highly specific cell separation in unprocessed complex samples at a throughput (ϕ > 100 mL h−1) 100× greater than that of conventional microfluidics. To achieve this goal, we have devised a new approach to micromagnetic sorting, the magnetic nickel iron electroformed trap (MagNET), which enables high flow rates by having millions of micromagnetic traps operate in parallel. Our design rotates the conventional microfluidic approach by 90° to form magnetic traps at the edges of pores instead of in channels, enabling millions of the magnetic traps to be incorporated into a centimeter sized device. Unlike previous work, where magnetic structures were defined using conventional microfabrication, we take inspiration from soft lithography and create a master from which many replica electroformed magnetic micropore devices can be economically manufactured. These free-standing 12 µm thick permalloy (Ni80Fe20) films contain micropores of arbitrary shape and position, allowing the device to be tailored for maximal capture efficiency and throughput. We demonstrate MagNET's capabilities by fabricating devices with both circular and rectangular pores and use these devices to rapidly (ϕ = 180 mL h−1) and specifically sort rare tumor cells from white blood cells. PMID:27170379

Aldefluor protocol to sort keratinocytes stem cells from skin

OpenAIRE

Noronha, Samuel Marcos Ribeiro; Gragnani, Alfredo; Pereira, Thiago Antônio Calado; Correa, Silvana Aparecida Alves; Bonucci, Jessica; Ferreira, Lydia Masako

2017-01-01

Abstract Purpose: To investigate the use Aldefluor® and N, N - Dimethylaminobenzaldehyde (DEAB) to design a protocol to sort keratinocyte stem cells from cultured keratinocytes from burned patients. Methods: Activated Aldefluor® aliquots were prepared and maintained at temperature between 2 to 8°C, or stored at -20°C. Next, the cells were collected following the standard protocol of sample preparation. Results: Best results were obtained with Aldefluor® 1.5µl and DEAB 15 µl for 1 x 106 c...

Flow cytometric sex sorting affects CD4 membrane distribution and binding of exogenous DNA on bovine sperm cells.

Science.gov (United States)

Domingues, William Borges; da Silveira, Tony Leandro Rezende; Komninou, Eliza Rossi; Monte, Leonardo Garcia; Remião, Mariana Härter; Dellagostin, Odir Antônio; Corcini, Carine Dahl; Varela Junior, Antônio Sergio; Seixas, Fabiana Kömmling; Collares, Tiago; Campos, Vinicius Farias

2017-08-01

Bovine sex-sorted sperm have been commercialized and successfully used for the production of transgenic embryos of the desired sex through the sperm-mediated gene transfer (SMGT) technique. However, sex-sorted sperm show a reduced ability to internalize exogenous DNA. The interaction between sperm cells and the exogenous DNA has been reported in other species to be a CD4-like molecule-dependent process. The flow cytometry-based sex-sorting process subjects the spermatozoa to different stresses causing changes in the cell membrane. The aim of this study was to elucidate the relationship between the redistribution of CD4-like molecules and binding of exogenous DNA to sex-sorted bovine sperm. In the first set of experiments, the membrane phospholipid disorder and the redistribution of the CD4 were evaluated. The second set of experiments was conducted to investigate the effect of CD4 redistribution on the mechanism of binding of exogenous DNA to sperm cells and the efficiency of lipofection in sex-sorted bovine sperm. Sex-sorting procedure increased the membrane phospholipid disorder and induced the redistribution of CD4-like molecules. Both X-sorted and Y-sorted sperm had decreased DNA bound to membrane in comparison with the unsorted sperm; however, the binding of the exogenous DNA was significantly increased with the addition of liposomes. Moreover, we demonstrated that the number of sperm-bound exogenous DNA was decreased when these cells were preincubated with anti-bovine CD4 monoclonal antibody, supporting our hypothesis that CD4-like molecules indeed play a crucial role in the process of exogenous DNA/bovine sperm cells interaction.

Immunoliposome-mediated delivery of neomycin phosphotransferase for the lineage-specific selection of differentiated/committed stem cell progenies: potential advantages over transfection with marker genes, fluorescence-activated and magnetic affinity cell-sorting.

Science.gov (United States)

Heng, Boon Chin; Cao, Tong

2005-01-01

A major challenge in the therapeutic application of stem cells in regenerative medicine is the lineage-specific selection of their committed/differentiated progenies for transplantation. This is necessary to avoid engraftment of undesired lineages at the transplantation site, i.e. fibroblastic scar tissue, as well as to enhance the efficacy of transplantation therapy. Commonly used techniques for lineage-specific selection of committed/differentiated stem cell progenies include marker gene transfection, fluorescence-activated (FACS) and magnetic-affinity (MACS) cell-sorting. Nevertheless, these have their disadvantages for therapeutic applications. Marker gene transfection invariably leads to permanent genetic modification of stem cells, which in turn limits their use in human clinical therapy due to overwhelming ethical and safety concerns. FACS requires expensive instrumentation and highly-skilled personnel, and is unsuited for handling bulk quantities of cells that would almost certainly be required for transplantation therapy. MACS is a cheaper alternative, but the level of purity attained is also reduced. A possible novel approach that has yet to be investigated is immunoliposome-mediated delivery of neomycin phosphotranferase (NPT) for lineage-specific selection of stem cell progenies. This would avoid permanent genetic modification to the cell, unlike recombinant NPT expression linked to activation of specific promoter sequences. Moreover, it could potentially provide a much more practical and cost-effective alternative for handling bulk quantities of cells that would be required for transplantation therapy, as compared to FACS or MACS. As such, this alternative approach needs to be rigorously investigated, in view of its potentially useful applications in stem cell therapeutics.

Rapid isolation of antibody from a synthetic human antibody library by repeated fluorescence-activated cell sorting (FACS.

Directory of Open Access Journals (Sweden)

Sung Sun Yim

Full Text Available Antibodies and their derivatives are the most important agents in therapeutics and diagnostics. Even after the significant progress in the technology for antibody screening from huge libraries, it takes a long time to isolate an antibody, which prevents a prompt action against the spread of a disease. Here, we report a new strategy for isolating desired antibodies from a combinatorial library in one day by repeated fluorescence-activated cell sorting (FACS. First, we constructed a library of synthetic human antibody in which single-chain variable fragment (scFv was expressed in the periplasm of Escherichia coli. After labeling the cells with fluorescent antigen probes, the highly fluorescent cells were sorted by using a high-speed cell sorter, and these cells were reused without regeneration in the next round of sorting. After repeating this sorting, the positive clones were completely enriched in several hours. Thus, we screened the library against three viral antigens, including the H1N1 influenza virus, Hepatitis B virus, and Foot-and-mouth disease virus. Finally, the potential antibody candidates, which show K(D values between 10 and 100 nM against the target antigens, could be successfully isolated even though the library was relatively small (∼ 10(6. These results show that repeated FACS screening without regeneration of the sorted cells can be a powerful method when a rapid response to a spreading disease is required.

Driving gradual endogenous c-myc overexpression by flow-sorting: intracellular signaling and tumor cell phenotype correlate with oncogene expression

DEFF Research Database (Denmark)

Knudsen, Kasper Jermiin; Holm, G.M.N.; Krabbe, J.S.

2009-01-01

Insulin-exposed rat mammary cancer cells were flow sorted based on a c-myc reporter plasmid encoding a destabilized green fluorescent protein. Sorted cells exhibited gradual increases in c-myc levels. Cells overexpressing c-myc by only 10% exhibited phenotypic changes attributable to c-myc overex...

Fluorescence-Activated Cell Sorting of EGFP-Labeled Neural Crest Cells From Murine Embryonic Craniofacial Tissue

Directory of Open Access Journals (Sweden)

Saurabh Singh

2005-01-01

Full Text Available During the early stages of embryogenesis, pluripotent neural crest cells (NCC are known to migrate from the neural folds to populate multiple target sites in the embryo where they differentiate into various derivatives, including cartilage, bone, connective tissue, melanocytes, glia, and neurons of the peripheral nervous system. The ability to obtain pure NCC populations is essential to enable molecular analyses of neural crest induction, migration, and/or differentiation. Crossing Wnt1-Cre and Z/EG transgenic mouse lines resulted in offspring in which the Wnt1-Cre transgene activated permanent EGFP expression only in NCC. The present report demonstrates a flow cytometric method to sort and isolate populations of EGFP-labeled NCC. The identity of the sorted neural crest cells was confirmed by assaying expression of known marker genes by TaqMan Quantitative Real-Time Polymerase Chain Reaction (QRT-PCR. The molecular strategy described in this report provides a means to extract intact RNA from a pure population of NCC thus enabling analysis of gene expression in a defined population of embryonic precursor cells critical to development.

Natural killer (NK)-cell activity in sorted subsets of peripheral blood mononuclear cells from patients with severe combined immunodeficiency

NARCIS (Netherlands)

ten Berge, R. J.; Schellekens, P. T.; Budding-Koppenol, A.; Dooren, L. J.; Vossen, J. M.

1987-01-01

Natural killer-cell activity for K562 target cells was measured in 13 patients with severe combined immunodeficiency before bone marrow transplantation. Both unseparated peripheral blood mononuclear cells and sorted cell subsets (B73.1 positive, B73.1 negative, OKT3 positive, OKT3 negative) were

Dramatic repositioning of c-Myb to different promoters during the cell cycle observed by combining cell sorting with chromatin immunoprecipitation.

Directory of Open Access Journals (Sweden)

Anita M Quintana

2011-02-01

Full Text Available The c-Myb transcription factor is a critical regulator of proliferation and stem cell differentiation, and mutated alleles of c-Myb are oncogenic, but little is known about changes in c-Myb activity during the cell cycle. To map the association of c-Myb with specific target genes during the cell cycle, we developed a novel Fix-Sort-ChIP approach, in which asynchronously growing cells were fixed with formaldehyde, stained with Hoechst 33342 and separated into different cell cycle fractions by flow sorting, then processed for chromatin immunoprecipitation (ChIP assays. We found that c-Myb actively repositions, binding to some genes only in specific cell cycle phases. In addition, the specificity of c-Myb is dramatically different in small subpopulations of cells, for example cells in the G2/M phase of the cell cycle, than in the bulk population. The repositioning of c-Myb during the cell cycle is not due to changes in its expression and also occurs with ectopically expressed, epitope-tagged versions of c-Myb. The repositioning occurs in established cell lines, in primary human CD34+ hematopoietic progenitors and in primary human acute myeloid leukemia cells. The combination of fixation, sorting and ChIP analysis sheds new light on the dynamic nature of gene regulation during the cell cycle and provides a new type of tool for the analysis of gene regulation in small subsets of cells, such as cells in a specific phase of the cell cycle.

Enrichment of rat oligodendrocyte progenitor cells by magnetic cell sorting

Czech Academy of Sciences Publication Activity Database

Čížková, D.; Čížek, M.; Nagyová, M.; Slovinská, L.; Novotná, I.; Jergová, S.; Radoňák, J.; Hlučilová, Jana; Vanický, I.

2009-01-01

Roč. 184, č. 1 (2009), s. 88-94 ISSN 0165-0270 R&D Projects: GA MŠk MEB0808108 Grant - others:Agentúra na podporu výskumu a vývoja(SK) APVV-51002105; Agentúra na podporu výskumu a vývoja(SK) APVV SK-CZ-0045-07 Institutional research plan: CEZ:AV0Z50450515 Keywords : Oligodendrocytes progenitors Lineage * Magnetic separation Subject RIV: FH - Neurology Impact factor: 2.295, year: 2009

Radiation effects on the species-specific cell sorting-out of the cellular slime molds

International Nuclear Information System (INIS)

Satow, Takashi

1976-01-01

The effects of gamma-rays irradiation on the development and the species-specific cell sorting-out of the cellular slime mold, Dictyostelium discoideum, were investigated. The interphase amoebae of the organism showed extremely resistant to 60 Co gamma-rays. The percentage of non-stained cells estimated by dye staining method was more than 90% at the dose of 270 kR. The amoebae irradiated at 270 kR performed the development similar in the most respects to that of the un-irradiated amoebae except that a little portion of the fruiting bodies were abnormal and that the appearance of aggregates and slugs delayed 3 hrs. The ability of the species-specific cell sorting-out was not affected by gamma-rays irradiation at 270 kR. (auth.)

Sorting white blood cells in microfabricated arrays

Science.gov (United States)

Castelino, Judith Andrea Rose

Fractionating white cells in microfabricated arrays presents the potential for detecting cells with abnormal adhesive or deformation properties. A possible application is separating nucleated fetal red blood cells from maternal blood. Since fetal cells are nucleated, it is possible to extract genetic information about the fetus from them. Separating fetal cells from maternal blood would provide a low cost noninvasive prenatal diagnosis for genetic defects, which is not currently available. We present results showing that fetal cells penetrate further into our microfabricated arrays than adult cells, and that it is possible to enrich the fetal cell fraction using the arrays. We discuss modifications to the array which would result in further enrichment. Fetal cells are less adhesive and more deformable than adult white cells. To determine which properties limit penetration, we compared the penetration of granulocytes and lymphocytes in arrays with different etch depths, constriction size, constriction frequency, and with different amounts of metabolic activity. The penetration of lymphocytes and granulocytes into constrained and unconstrained arrays differed qualitatively. In constrained arrays, the cells were activated by repeated shearing, and the number of cells stuck as a function of distance fell superexponentially. In unconstrained arrays the number of cells stuck fell slower than an exponential. We attribute this result to different subpopulations of cells with different sticking parameters. We determined that penetration in unconstrained arrays was limited by metabolic processes, and that when metabolic activity was reduced penetration was limited by deformability. Fetal cells also contain a different form of hemoglobin with a higher oxygen affinity than adult hemoglobin. Deoxygenated cells are paramagnetic and are attracted to high magnetic field gradients. We describe a device which can separate cells using 10 μm magnetic wires to deflect the paramagnetic

Self-assembled magnetic filter for highly efficient immunomagnetic separation.

Science.gov (United States)

Issadore, David; Shao, Huilin; Chung, Jaehoon; Newton, Andita; Pittet, Mikael; Weissleder, Ralph; Lee, Hakho

2011-01-07

We have developed a compact and inexpensive microfluidic chip, the self-assembled magnetic filter, to efficiently remove magnetically tagged cells from suspension. The self-assembled magnetic filter consists of a microfluidic channel built directly above a self-assembled NdFeB magnet. Micrometre-sized grains of NdFeB assemble to form alternating magnetic dipoles, creating a magnetic field with a very strong magnitude B (from the material) and field gradient ▽B (from the configuration) in the microfluidic channel. The magnetic force imparted on magnetic beads is measured to be comparable to state-of-the-art microfabricated magnets, allowing for efficient separations to be performed in a compact, simple device. The efficiency of the magnetic filter is characterized by sorting non-magnetic (polystyrene) beads from magnetic beads (iron oxide). The filter enriches the population of non-magnetic beads to magnetic beads by a factor of >10(5) with a recovery rate of 90% at 1 mL h(-1). The utility of the magnetic filter is demonstrated with a microfluidic device that sorts tumor cells from leukocytes using negative immunomagnetic selection, and concentrates the tumor cells on an integrated membrane filter for optical detection.

Perbandingan Kecepatan Gabungan Algoritma Quick Sort dan Merge Sort dengan Insertion Sort, Bubble Sort dan Selection Sort

OpenAIRE

Al Rivan, Muhammad Ezar

2017-01-01

Ordering is one of the process done before doing data processing. The sorting algorithm has its own strengths and weaknesses. By taking strengths of each algorithm then combined can be a better algorithm. Quick Sort and Merge Sort are algorithms that divide the data into parts and each part divide again into sub-section until one element. Usually one element join with others and then sorted by. In this experiment data divide into parts that have size not more than threshold. This part then so...

COST EVALUATION OF AUTOMATED AND MANUAL POST- CONSUMER PLASTIC BOTTLE SORTING SYSTEMS

Science.gov (United States)

This project evaluates, on the basis of performance and cost, two Automated BottleSort® sorting systems for post-consumer commingled plastic containers developed by Magnetic Separation Systems. This study compares the costs to sort mixed bales of post-consumer plastic at these t...

Microfluidic devices for analysis and active optical sorting of individual cells

Czech Academy of Sciences Publication Activity Database

Ježek, Jan; Pilát, Zdeněk; Šerý, Mojmír; Kaňka, Jan; Samek, Ota; Bernatová, Silvie; Zemánek, Pavel

2013-01-01

Roč. 58, č. 2 (2013), s. 55-59 ISSN 0447-6441 R&D Projects: GA MPO FR-TI1/433; GA MŠk ED0017/01/01; GA ČR GAP205/11/1687 Institutional support: RVO:68081731 Keywords : microfluidic * cell sorting * optical tweezers * Raman spectroscopy Subject RIV: EI - Biotechnology ; Bionics

Transport and sorting of sphingolipids in polarized cells : the involvement of the sub-apical compartment

NARCIS (Netherlands)

IJzendoorn, Sven Christian David van

1999-01-01

The work described in this thesis has provided a novel insight into the process of sphingolipid transport and sorting in polarized cells. We have used HepG2 cells as a model system to study polarized traffic in hepatic cells. Under specific culture conditions, HepG2 cells acquire a polarized

Toward microfluidic sperm refinement: continuous flow label-free analysis and sorting of sperm cells

NARCIS (Netherlands)

de Wagenaar, B.; Dekker, Stefan; van den Berg, Albert; Segerink, Loes Irene

2015-01-01

This manuscript reports upon the development of a microfluidic setup to detect and sort sperm cells from polystyrene beads label-free and non-invasively. Detection is performed by impedance analysis. When sperm cells passed the microelectrodes, the recorded impedance (19.6 ± 5.7 Ω) was higher

Binar Sort: A Linear Generalized Sorting Algorithm

OpenAIRE

Gilreath, William F.

2008-01-01

Sorting is a common and ubiquitous activity for computers. It is not surprising that there exist a plethora of sorting algorithms. For all the sorting algorithms, it is an accepted performance limit that sorting algorithms are linearithmic or O(N lg N). The linearithmic lower bound in performance stems from the fact that the sorting algorithms use the ordering property of the data. The sorting algorithm uses comparison by the ordering property to arrange the data elements from an initial perm...

Fine-tuning of T-cell development by the CD3γ di-leucine-based TCR-sorting motif

DEFF Research Database (Denmark)

Lauritsen, Jens Peter Holst; Boding, Lasse; Buus, Terkild B

2015-01-01

The CD3γ di-leucine-based (diL) receptor-sorting motif plays a central role in TCR down-regulation and in clonal expansion of virus-specific T cells. However, the role of the CD3γ diL motif in T-cell development is not known. In this study, we show that protein kinase C-induced TCR down-regulatio......The CD3γ di-leucine-based (diL) receptor-sorting motif plays a central role in TCR down-regulation and in clonal expansion of virus-specific T cells. However, the role of the CD3γ diL motif in T-cell development is not known. In this study, we show that protein kinase C-induced TCR down...

Measuring and sorting cell populations expressing isospectral fluorescent proteins with different fluorescence lifetimes.

Directory of Open Access Journals (Sweden)

Bryan Sands

Full Text Available Study of signal transduction in live cells benefits from the ability to visualize and quantify light emitted by fluorescent proteins (XFPs fused to different signaling proteins. However, because cell signaling proteins are often present in small numbers, and because the XFPs themselves are poor fluorophores, the amount of emitted light, and the observable signal in these studies, is often small. An XFP's fluorescence lifetime contains additional information about the immediate environment of the fluorophore that can augment the information from its weak light signal. Here, we constructed and expressed in Saccharomyces cerevisiae variants of Teal Fluorescent Protein (TFP and Citrine that were isospectral but had shorter fluorescence lifetimes, ∼ 1.5 ns vs ∼ 3 ns. We modified microscopic and flow cytometric instruments to measure fluorescence lifetimes in live cells. We developed digital hardware and a measure of lifetime called a "pseudophasor" that we could compute quickly enough to permit sorting by lifetime in flow. We used these abilities to sort mixtures of cells expressing TFP and the short-lifetime TFP variant into subpopulations that were respectively 97% and 94% pure. This work demonstrates the feasibility of using information about fluorescence lifetime to help quantify cell signaling in living cells at the high throughput provided by flow cytometry. Moreover, it demonstrates the feasibility of isolating and recovering subpopulations of cells with different XFP lifetimes for subsequent experimentation.

Seamless Combination of Fluorescence-Activated Cell Sorting and Hanging-Drop Networks for Individual Handling and Culturing of Stem Cells and Microtissue Spheroids.

Science.gov (United States)

Birchler, Axel; Berger, Mischa; Jäggin, Verena; Lopes, Telma; Etzrodt, Martin; Misun, Patrick Mark; Pena-Francesch, Maria; Schroeder, Timm; Hierlemann, Andreas; Frey, Olivier

2016-01-19

Open microfluidic cell culturing devices offer new possibilities to simplify loading, culturing, and harvesting of individual cells or microtissues due to the fact that liquids and cells/microtissues are directly accessible. We present a complete workflow for microfluidic handling and culturing of individual cells and microtissue spheroids, which is based on the hanging-drop network concept: The open microfluidic devices are seamlessly combined with fluorescence-activated cell sorting (FACS), so that individual cells, including stem cells, can be directly sorted into specified culturing compartments in a fully automated way and at high accuracy. Moreover, already assembled microtissue spheroids can be loaded into the microfluidic structures by using a conventional pipet. Cell and microtissue culturing is then performed in hanging drops under controlled perfusion. On-chip drop size control measures were applied to stabilize the system. Cells and microtissue spheroids can be retrieved from the chip by using a parallelized transfer method. The presented methodology holds great promise for combinatorial screening of stem-cell and multicellular-spheroid cultures.

LazySorted: A Lazily, Partially Sorted Python List

Directory of Open Access Journals (Sweden)

Naftali Harris

2015-06-01

Full Text Available LazySorted is a Python C extension implementing a partially and lazily sorted list data structure. It solves a common problem faced by programmers, in which they need just part of a sorted list, like its middle element (the median, but sort the entire list to get it. LazySorted presents them with the abstraction that they are working with a fully sorted list, while actually only sorting the list partially with quicksort partitions to return the requested sub-elements. This enables programmers to use naive "sort first" algorithms but nonetheless attain linear run-times when possible. LazySorted may serve as a drop-in replacement for the built-in sorted function in most cases, and can sometimes achieve run-times more than 7 times faster.

Exploring viral reservoir: The combining approach of cell sorting and droplet digital PCR.

Science.gov (United States)

Gibellini, Lara; Pecorini, Simone; De Biasi, Sara; Pinti, Marcello; Bianchini, Elena; De Gaetano, Anna; Digaetano, Margherita; Pullano, Rosalberta; Lo Tartaro, Domenico; Iannone, Anna; Mussini, Cristina; Cossarizza, Andrea; Nasi, Milena

2018-02-01

Combined antiretroviral therapy (cART) blocks different steps of HIV replication and maintains plasma viral RNA at undetectable levels. The virus can remain in long-living cells and create a reservoir where HIV can restart replicating after cART discontinuation. A persistent viral production triggers and maintains a persistent immune activation, which is a well-known feature of chronic HIV infection, and contributes either to precocious aging, or to the increased incidence of morbidity and mortality of HIV positive patients. The new frontier of the treatment of HIV infection is nowadays eradication of the virus from all host cells and tissues. For this reason, it is crucial to have a clear and precise idea of where the virus hides, and which are the cells that keep it silent. Important efforts have been made to improve the detection of viral reservoirs, and new techniques are now giving the opportunity to characterize viral reservoirs. Among these techniques, a strategic approach based upon cell sorting and droplet digital PCR (ddPCR) is opening new horizons and opportunities of research. This review provides an overview of the methods that combine cell sorting and ddPCR for the quantification of HIV DNA in different cell types, and for the detection of its maintenance. Copyright © 2017 Elsevier Inc. All rights reserved.

Digital sorting of complex tissues for cell type-specific gene expression profiles.

Science.gov (United States)

Zhong, Yi; Wan, Ying-Wooi; Pang, Kaifang; Chow, Lionel M L; Liu, Zhandong

2013-03-07

Cellular heterogeneity is present in almost all gene expression profiles. However, transcriptome analysis of tissue specimens often ignores the cellular heterogeneity present in these samples. Standard deconvolution algorithms require prior knowledge of the cell type frequencies within a tissue or their in vitro expression profiles. Furthermore, these algorithms tend to report biased estimations. Here, we describe a Digital Sorting Algorithm (DSA) for extracting cell-type specific gene expression profiles from mixed tissue samples that is unbiased and does not require prior knowledge of cell type frequencies. The results suggest that DSA is a specific and sensitivity algorithm in gene expression profile deconvolution and will be useful in studying individual cell types of complex tissues.

Targeted sorting of single virus-infected cells of the coccolithophore Emiliania huxleyi.

Science.gov (United States)

Martínez Martínez, Joaquín; Poulton, Nicole J; Stepanauskas, Ramunas; Sieracki, Michael E; Wilson, William H

2011-01-01

Discriminating infected from healthy cells is the first step to understanding the mechanisms and ecological implications of viral infection. We have developed a method for detecting, sorting, and performing molecular analysis of individual, infected cells of the important microalga Emiliania huxleyi, based on known physiological responses to viral infection. Of three fluorescent dyes tested, FM 1-43 (for detecting membrane blebbing) gave the most unequivocal and earliest separation of cells. Furthermore, we were able to amplify the genomes of single infected cells using Multiple Displacement Amplification. This novel method to reliably discriminate infected from healthy cells in cultures will allow researchers to answer numerous questions regarding the mechanisms and implications of viral infection of E. huxleyi. The method may be transferable to other virus-host systems.

Cell cycle variation in x-ray survival for cells from spheroids measured by volume cell sorting

International Nuclear Information System (INIS)

Freyer, J.P.; Wilder, M.E.; Raju, M.R.

1984-01-01

Considerable work has been done studying the variation in cell survival as a function of cell cycle position for monolayers or single cells exposed to radiation. Little is known about the effects of multicellular growth on the relative radiation sensitivity of cells in different cell cycle stages. The authors have developed a new technique for measuring the response of cells, using volume cell sorting, which is rapid, non-toxic, and does not require cell synchronization. By combining this technique with selective spheroid dissociation,they have measured the age response of cells located at various depths in EMT6 and Colon 26 spheroids. Although cells in the inner region had mostly G1-phase DNA contents, 15-20% had S- and G2-phase DNA contents. Analysis of these cells using BrdU labeling and flow cytometric analysis with a monoclonal antibody to BrdU indicated that the inner region cells were not synthesizing DNA. Thus, the authors were able to measure the radiation response of cells arrested in G1, S and G2 cell cycle phases. Comparison of inner and outer spheroid regions, and monolayer cultures, indicates that it is improper to extrapolate age response data in standard culture conditions to the situation in spheroids

Sorting Out Sorts

OpenAIRE

Jonathan B. Berk

1998-01-01

In this paper we analyze the theoretical implications of sorting data into groups and then running asset pricing tests within each group. We show that the way this procedure is implemented introduces a severe bias in favor of rejecting the model under consideration. By simply picking enough groups to sort into even the true asset pricing model can be shown to have no explanatory power within each group.

Sorting Tubules Regulate Blood-Brain Barrier Transcytosis

Directory of Open Access Journals (Sweden)

Roberto Villaseñor

2017-12-01

Full Text Available Transcytosis across the blood-brain barrier (BBB regulates key processes of the brain, but the intracellular sorting mechanisms that determine successful receptor-mediated transcytosis in brain endothelial cells (BECs remain unidentified. Here, we used Transferrin receptor-based Brain Shuttle constructs to investigate intracellular transport in BECs, and we uncovered a pathway for the regulation of receptor-mediated transcytosis. By combining live-cell imaging and mathematical modeling in vitro with super-resolution microscopy of the BBB, we show that intracellular tubules promote transcytosis across the BBB. A monovalent construct (sFab sorted for transcytosis was localized to intracellular tubules, whereas a bivalent construct (dFab sorted for degradation formed clusters with impaired transport along tubules. Manipulating tubule biogenesis by overexpressing the small GTPase Rab17 increased dFab transport into tubules and induced its transcytosis in BECs. We propose that sorting tubules regulate transcytosis in BECs and may be a general mechanism for receptor-mediated transport across the BBB.

Verification of counting sort and radix sort

NARCIS (Netherlands)

C.P.T. de Gouw (Stijn); F.S. de Boer (Frank); J.C. Rot (Jurriaan)

2016-01-01

textabstractSorting is an important algorithmic task used in many applications. Two main aspects of sorting algorithms which have been studied extensively are complexity and correctness. [Foley and Hoare, 1971] published the first formal correctness proof of a sorting algorithm (Quicksort). While

Targeted sorting of single virus-infected cells of the coccolithophore Emiliania huxleyi.

Directory of Open Access Journals (Sweden)

Joaquín Martínez Martínez

Full Text Available Discriminating infected from healthy cells is the first step to understanding the mechanisms and ecological implications of viral infection. We have developed a method for detecting, sorting, and performing molecular analysis of individual, infected cells of the important microalga Emiliania huxleyi, based on known physiological responses to viral infection. Of three fluorescent dyes tested, FM 1-43 (for detecting membrane blebbing gave the most unequivocal and earliest separation of cells. Furthermore, we were able to amplify the genomes of single infected cells using Multiple Displacement Amplification. This novel method to reliably discriminate infected from healthy cells in cultures will allow researchers to answer numerous questions regarding the mechanisms and implications of viral infection of E. huxleyi. The method may be transferable to other virus-host systems.

Phenotypic and functional characterization of earthworm coelomocyte subsets: Linking light scatter-based cell typing and imaging of the sorted populations.

Science.gov (United States)

Engelmann, Péter; Hayashi, Yuya; Bodó, Kornélia; Ernszt, Dávid; Somogyi, Ildikó; Steib, Anita; Orbán, József; Pollák, Edit; Nyitrai, Miklós; Németh, Péter; Molnár, László

2016-12-01

Flow cytometry is a common approach to study invertebrate immune cells including earthworm coelomocytes. However, the link between light-scatter- and microscopy-based phenotyping remains obscured. Here we show, by means of light scatter-based cell sorting, both subpopulations (amoebocytes and eleocytes) can be physically isolated with good sort efficiency and purity confirmed by downstream morphological and cytochemical applications. Immunocytochemical analysis using anti-EFCC monoclonal antibodies combined with phalloidin staining has revealed antigenically distinct, sorted subsets. Screening of lectin binding capacity indicated wheat germ agglutinin (WGA) as the strongest reactor to amoebocytes. This is further evidenced by WGA inhibition assays that suggest high abundance of N-acetyl-d-glucosamine in amoebocytes. Post-sort phagocytosis assays confirmed the functional differences between amoebocytes and eleocytes, with the former being in favor of bacterial engulfment. This study has proved successful in linking flow cytometry and microscopy analysis and provides further experimental evidence of phenotypic and functional heterogeneity in earthworm coelomocyte subsets. Copyright © 2016 Elsevier Ltd. All rights reserved.

Endosomal sorting complexes required for ESCRTing cells toward death during neurogenesis, neurodevelopment and neurodegeneration.

Science.gov (United States)

Kaul, Zenia; Chakrabarti, Oishee

2018-03-25

The endosomal sorting complexes required for transport (ESCRT) proteins help in the recognition, sorting and degradation of ubiquitinated cargoes from the cell surface, long-lived proteins or aggregates, and aged organelles present in the cytosol. These proteins take part in the endo-lysosomal system of degradation. The ESCRT proteins also play an integral role in cytokinesis, viral budding and mRNA transport. Many neurodegenerative diseases are caused by toxic accumulation of cargo in the cell, which causes stress and ultimately leads to neuronal death. This accumulation of cargo occurs because of defects in the endo-lysosomal degradative pathway-loss of function of ESCRTs has been implicated in this mechanism. ESCRTs also take part in many survival processes, lack of which can culminate in neuronal cell death. While the role played by the ESCRT proteins in maintaining healthy neurons is known, their role in neurodegenerative diseases is still poorly understood. In this review, we highlight the importance of ESCRTs in maintaining healthy neurons and then suggest how perturbations in many of the survival mechanisms governed by these proteins could eventually lead to cell death; quite often these correlations are not so obviously laid out. Extensive neuronal death eventually culminates in neurodegeneration. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Approaches for cytogenetic and molecular analyses of small flow-sorted cell populations from childhood leukemia bone marrow samples

DEFF Research Database (Denmark)

Obro, Nina Friesgaard; Madsen, Hans O.; Ryder, Lars Peter

2011-01-01

defined cell populations with subsequent analyses of leukemia-associated cytogenetic and molecular marker. The approaches described here optimize the use of the same tube of unfixed, antibody-stained BM cells for flow-sorting of small cell populations and subsequent exploratory FISH and PCR-based analyses....

Passive circulating cell sorting by deformability using a microfluidic gradual filter.

Science.gov (United States)

Preira, P; Grandné, V; Forel, J-M; Gabriele, S; Camara, M; Theodoly, O

2013-01-07

The deformability of circulating leukocytes plays an important role in the physiopathology of several diseases like sepsis or acute respiratory distress syndrome (ARDS). We present here a microfluidic method for the passive testing, sorting and separating of non-adherent cell populations by deformability. It consists of microfluidic sieves in series with pore sizes decreasing from the upstream to the downstream. The method capabilities are demonstrated with monocytic cell lines (THP-1) treated by Jasplakinolide (a stabilizer of polymerized actin), LatrunculinA (an inhibitor of actin polymerization), and with the plasma of patients suffering from ARDS. Simple sample injection with standard syringes and pumps makes the method readily adapted for experimentation in hospitals.

Efficient Parallel Sorting for Migrating Birds Optimization When Solving Machine-Part Cell Formation Problems

Directory of Open Access Journals (Sweden)

Ricardo Soto

2016-01-01

Full Text Available The Machine-Part Cell Formation Problem (MPCFP is a NP-Hard optimization problem that consists in grouping machines and parts in a set of cells, so that each cell can operate independently and the intercell movements are minimized. This problem has largely been tackled in the literature by using different techniques ranging from classic methods such as linear programming to more modern nature-inspired metaheuristics. In this paper, we present an efficient parallel version of the Migrating Birds Optimization metaheuristic for solving the MPCFP. Migrating Birds Optimization is a population metaheuristic based on the V-Flight formation of the migrating birds, which is proven to be an effective formation in energy saving. This approach is enhanced by the smart incorporation of parallel procedures that notably improve performance of the several sorting processes performed by the metaheuristic. We perform computational experiments on 1080 benchmarks resulting from the combination of 90 well-known MPCFP instances with 12 sorting configurations with and without threads. We illustrate promising results where the proposal is able to reach the global optimum in all instances, while the solving time with respect to a nonparallel approach is notably reduced.

Protein purification using magnetic adsorbent particles

DEFF Research Database (Denmark)

Franzreb, M; Siemann-Herzberg, M.; Hobley, Timothy John

2006-01-01

The application of functionalised magnetic adsorbent particles in combination with magnetic separation techniques has received considerable attention in recent years. The magnetically responsive nature of such adsorbent particles permits their selective manipulation and separation in the presence...... separations are fast, gentle, scaleable, easily automated, can achieve separations that would be impossible or impractical to achieve by other techniques, and have demonstrated credibility in a wide range of disciplines, including minerals processing, wastewater treatment, molecular biology, cell sorting...

Life on magnets: stem cell networking on micro-magnet arrays.

Science.gov (United States)

Zablotskii, Vitalii; Dejneka, Alexandr; Kubinová, Šárka; Le-Roy, Damien; Dumas-Bouchiat, Frédéric; Givord, Dominique; Dempsey, Nora M; Syková, Eva

2013-01-01

Interactions between a micro-magnet array and living cells may guide the establishment of cell networks due to the cellular response to a magnetic field. To manipulate mesenchymal stem cells free of magnetic nanoparticles by a high magnetic field gradient, we used high quality micro-patterned NdFeB films around which the stray field's value and direction drastically change across the cell body. Such micro-magnet arrays coated with parylene produce high magnetic field gradients that affect the cells in two main ways: i) causing cell migration and adherence to a covered magnetic surface and ii) elongating the cells in the directions parallel to the edges of the micro-magnet. To explain these effects, three putative mechanisms that incorporate both physical and biological factors influencing the cells are suggested. It is shown that the static high magnetic field gradient generated by the micro-magnet arrays are capable of assisting cell migration to those areas with the strongest magnetic field gradient, thereby allowing the build up of tunable interconnected stem cell networks, which is an elegant route for tissue engineering and regenerative medicine.

Life on magnets: stem cell networking on micro-magnet arrays.

Directory of Open Access Journals (Sweden)

Vitalii Zablotskii

Full Text Available Interactions between a micro-magnet array and living cells may guide the establishment of cell networks due to the cellular response to a magnetic field. To manipulate mesenchymal stem cells free of magnetic nanoparticles by a high magnetic field gradient, we used high quality micro-patterned NdFeB films around which the stray field's value and direction drastically change across the cell body. Such micro-magnet arrays coated with parylene produce high magnetic field gradients that affect the cells in two main ways: i causing cell migration and adherence to a covered magnetic surface and ii elongating the cells in the directions parallel to the edges of the micro-magnet. To explain these effects, three putative mechanisms that incorporate both physical and biological factors influencing the cells are suggested. It is shown that the static high magnetic field gradient generated by the micro-magnet arrays are capable of assisting cell migration to those areas with the strongest magnetic field gradient, thereby allowing the build up of tunable interconnected stem cell networks, which is an elegant route for tissue engineering and regenerative medicine.

Magnetic particle mixing with magnetic micro-convection for microfluidics

International Nuclear Information System (INIS)

Kitenbergs, Guntars; Erglis, Kaspars; Perzynski, Régine; Cēbers, Andrejs

2015-01-01

In this paper we discuss the magnetic micro-convection phenomenon as a tool for mixing enhancement in microfluidics systems in cases when one of the miscible fluids is a magnetic particle colloid. A system of a water-based magnetic fluid and water is investigated experimentally under homogeneous magnetic field in a Hele–Shaw cell. Subsequent image analysis both qualitatively and quantitatively reveals the high enhancement of mixing efficiency provided by this method. The mixing efficiency dependence on the magnetic field and the physical limits is discussed. A suitable model for a continuous-flow microfluidics setup for mixing with magnetic micro-convection is also proposed and justified with an experiment. In addition, possible applications in improving the speed of ferrohydrodynamic sorting and magnetic label or selected tracer mixing in lab on a chip systems are noted. - Highlights: • We study the magnetic micro-convection as a mixing method in microfluidics. • We show that the method enhances mixing with magnetic field squared dependency. • We propose a flow cell setup for mixing and justify it with a sample experiment. • The mixing method can be easily implemented in an existing microfluidics setup

Perbandingan Bubble Sort dengan Insertion Sort pada Bahasa Pemrograman C dan Fortran

OpenAIRE

Reina, Reina; Gautama, Josef Bernadi

2013-01-01

Sorting is a basic algorithm studied by students of computer science major. Sorting algorithm is the basis of other algorithms such as searching algorithm, pattern matching algorithm. Bubble sort is a popular basic sorting algorithm due to its easiness to be implemented. Besides bubble sort, there is insertion sort. It is lesspopular than bubble sort because it has more difficult algorithm. This paper discusses about process time between insertion sort and bubble sort with two kinds of data. ...

echinus, required for interommatidial cell sorting and cell death in the Drosophila pupal retina, encodes a protein with homology to ubiquitin-specific proteases

Directory of Open Access Journals (Sweden)

Gorski Sharon M

2007-07-01

Full Text Available Abstract Background Programmed cell death is used to remove excess cells between ommatidia in the Drosophila pupal retina. This death is required to establish the crystalline, hexagonal packing of ommatidia that characterizes the adult fly eye. In previously described echinus mutants, interommatidial cell sorting, which precedes cell death, occurred relatively normally. Interommatidial cell death was partially suppressed, resulting in adult eyes that contained excess pigment cells, and in which ommatidia were mildly disordered. These results have suggested that echinus functions in the pupal retina primarily to promote interommatidial cell death. Results We generated a number of new echinus alleles, some likely null mutants. Analysis of these alleles provides evidence that echinus has roles in cell sorting as well as cell death. echinus encodes a protein with homology to ubiquitin-specific proteases. These proteins cleave ubiquitin-conjugated proteins at the ubiquitin C-terminus. The echinus locus encodes multiple splice forms, including two proteins that lack residues thought to be critical for deubiquitination activity. Surprisingly, ubiquitous expression in the eye of versions of Echinus that lack residues critical for ubiquitin specific protease activity, as well as a version predicted to be functional, rescue the echinus loss-of-function phenotype. Finally, genetic interactions were not detected between echinus loss and gain-of-function and a number of known apoptotic regulators. These include Notch, EGFR, the caspases Dronc, Drice, Dcp-1, Dream, the caspase activators, Rpr, Hid, and Grim, the caspase inhibitor DIAP1, and Lozenge or Klumpfuss. Conclusion The echinus locus encodes multiple splice forms of a protein with homology to ubiquitin-specific proteases, but protease activity is unlikely to be required for echinus function, at least when echinus is overexpressed. Characterization of likely echinus null alleles and genetic interactions

Perbandingan Bubble Sort dengan Insertion Sort pada Bahasa Pemrograman C dan Fortran

Directory of Open Access Journals (Sweden)

Reina Reina

2013-12-01

Full Text Available Sorting is a basic algorithm studied by students of computer science major. Sorting algorithm is the basis of other algorithms such as searching algorithm, pattern matching algorithm. Bubble sort is a popular basic sorting algorithm due to its easiness to be implemented. Besides bubble sort, there is insertion sort. It is lesspopular than bubble sort because it has more difficult algorithm. This paper discusses about process time between insertion sort and bubble sort with two kinds of data. First is randomized data, and the second is data of descending list. Comparison of process time has been done in two kinds of programming language that is C programming language and FORTRAN programming language. The result shows that bubble sort needs more time than insertion sort does.

Schisandrin B protects PC12 cells by decreasing the expression of amyloid precursor protein and vacuolar protein sorting 35★

Science.gov (United States)

Yan, Mingmin; Mao, Shanping; Dong, Huimin; Liu, Baohui; Zhang, Qian; Pan, Gaofeng; Fu, Zhiping

2012-01-01

PC12 cell injury was induced using 20 μM amyloid β-protein 25–35 to establish a model of Alzheimer's disease. The cells were then treated with 5, 10, and 25 μM Schisandrin B. Methylthiazolyldiphenyl-tetrazolium bromide assays and Hoechst 33342 staining results showed that with increasing Schisandrin B concentration, the survival rate of PC12 cells injured by amyloid β-protein 25–35 gradually increased and the rate of apoptosis gradually decreased. Reverse transcription-PCR, immunocytochemical staining and western blot results showed that with increasing Schisandrin B concentration, the mRNA and protein expression of vacuolar protein sorting 35 and amyloid precursor protein were gradually decreased. Vacuolar protein sorting 35 and amyloid precursor protein showed a consistent trend for change. These findings suggest that 5, 10, and 25 μM Schisandrin B antagonizes the cellular injury induced by amyloid β-protein 25–35 in a dose-dependent manner. This may be caused by decreasing the expression of vacuolar protein sorting 35 and amyloid precursor protein. PMID:25745458

Responses of Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus to Simulated Food Processing Treatments, Determined Using Fluorescence-Activated Cell Sorting and Plate Counting▿

Science.gov (United States)

Kennedy, Deirdre; Cronin, Ultan P.; Wilkinson, Martin G.

2011-01-01

Three common food pathogenic microorganisms were exposed to treatments simulating those used in food processing. Treated cell suspensions were then analyzed for reduction in growth by plate counting. Flow cytometry (FCM) and fluorescence-activated cell sorting (FACS) were carried out on treated cells stained for membrane integrity (Syto 9/propidium iodide) or the presence of membrane potential [DiOC2(3)]. For each microbial species, representative cells from various subpopulations detected by FCM were sorted onto selective and nonselective agar and evaluated for growth and recovery rates. In general, treatments giving rise to the highest reductions in counts also had the greatest effects on cell membrane integrity and membrane potential. Overall, treatments that impacted cell membrane permeability did not necessarily have a comparable effect on membrane potential. In addition, some bacterial species with extensively damaged membranes, as detected by FCM, appeared to be able to replicate and grow after sorting. Growth of sorted cells from various subpopulations was not always reflected in plate counts, and in some cases the staining protocol may have rendered cells unculturable. Optimized FCM protocols generated a greater insight into the extent of the heterogeneous bacterial population responses to food control measures than did plate counts. This study underlined the requirement to use FACS to relate various cytometric profiles generated by various staining protocols with the ability of cells to grow on microbial agar plates. Such information is a prerequisite for more-widespread adoption of FCM as a routine microbiological analytical technique. PMID:21602370

Identification of residual leukemic cells by flow cytometry in childhood B-cell precursor acute lymphoblastic leukemia: verification of leukemic state by flow-sorting and molecular/cytogenetic methods

DEFF Research Database (Denmark)

Obro, Nina F; Ryder, Lars P; Madsen, Hans O

2012-01-01

Reduction in minimal residual disease, measured by real-time quantitative PCR or flow cytometry, predicts prognosis in childhood B-cell precursor acute lymphoblastic leukemia. We explored whether cells reported as minimal residual disease by flow cytometry represent the malignant clone harboring...... clone-specific genomic markers (53 follow-up bone marrow samples from 28 children with B-cell precursor acute lymphoblastic leukemia). Cell populations (presumed leukemic and non-leukemic) were flow-sorted during standard flow cytometry-based minimal residual disease monitoring and explored by PCR and....../or fluorescence in situ hybridization. We found good concordance between flow cytometry and genomic analyses in the individual flow-sorted leukemic (93% true positive) and normal (93% true negative) cell populations. Four cases with discrepant results had plausible explanations (e.g. partly informative...

Size and dielectric properties of skeletal stem cells change critically after enrichment and expansion from human bone marrow: consequences for microfluidic cell sorting.

Science.gov (United States)

Xavier, Miguel; de Andrés, María C; Spencer, Daniel; Oreffo, Richard O C; Morgan, Hywel

2017-08-01

The capacity of bone and cartilage to regenerate can be attributed to skeletal stem cells (SSCs) that reside within the bone marrow (BM). Given SSCs are rare and lack specific surface markers, antibody-based sorting has failed to deliver the cell purity required for clinical translation. Microfluidics offers new methods of isolating cells based on biophysical features including, but not limited to, size, electrical properties and stiffness. Here we report the characterization of the dielectric properties of unexpanded SSCs using single-cell microfluidic impedance cytometry (MIC). Unexpanded SSCs had a mean size of 9.0 µm; larger than the majority of BM cells. During expansion, often used to purify and increase the number of SSCs, cell size and membrane capacitance increased significantly, highlighting the importance of characterizing unaltered SSCs. In addition, MIC was used to track the osteogenic differentiation of SSCs and showed an increased membrane capacitance with differentiation. The electrical properties of primary SSCs were indistinct from other BM cells precluding its use as an isolation method. However, the current studies indicate that cell size in combination with another biophysical parameter, such as stiffness, could be used to design label-free devices for sorting SSCs with significant clinical impact. © 2017 The Authors.

Sorting on the basis of deformability of single cells in a femtosecond laser fabricated optofluidic device

Science.gov (United States)

Bragheri, F.; Paiè, P.; Yang, T.; Nava, G.; Martınez Vázquez, R.; Di Tano, M.; Veglione, M.; Minzioni, P.; Mondello, C.; Cristiani, I.; Osellame, R.

2015-03-01

Optical stretching is a powerful technique for the mechanical phenotyping of single suspended cells that exploits cell deformability as an inherent functional marker. Dual-beam optical trapping and stretching of cells is a recognized tool to investigate their viscoelastic properties. The optical stretcher has the ability to deform cells through optical forces without physical contact or bead attachment. In addition, it is the only method that can be combined with microfluidic delivery, allowing for the serial, high-throughput measurement of the optical deformability and the selective sorting of single specific cells. Femtosecond laser micromachining can fabricate in the same chip both the microfluidic channel and the optical waveguides, producing a monolithic device with a very precise alignment between the components and very low sensitivity to external perturbations. Femtosecond laser irradiation in a fused silica chip followed by chemical etching in hydrofluoric acid has been used to fabricate the microfluidic channels where the cells move by pressure-driven flow. With the same femtosecond laser source two optical waveguides, orthogonal to the microfluidic channel and opposing each other, have been written inside the chip. Here we present an optimized writing process that provides improved wall roughness of the micro-channels allowing high-quality imaging. In addition, we will show results on cell sorting on the basis of mechanical properties in the same device: the different deformability exhibited by metastatic and tumorigenic cells has been exploited to obtain a metastasis-cells enriched sample. The enrichment is verified by exploiting, after cells collection, fluorescence microscopy.

Design and realization of sort manipulator of crystal-angle sort machine

Science.gov (United States)

Wang, Ming-shun; Chen, Shu-ping; Guan, Shou-ping; Zhang, Yao-wei

2005-12-01

It is a current tendency of development in automation technology to replace manpower with manipulators in working places where dangerous, harmful, heavy or repetitive work is involved. The sort manipulator is installed in a crystal-angle sort machine to take the place of manpower, and engaged in unloading and sorting work. It is the outcome of combing together mechanism, electric transmission, and pneumatic element and micro-controller control. The step motor makes the sort manipulator operate precisely. The pneumatic elements make the sort manipulator be cleverer. Micro-controller's software bestows some simple artificial intelligence on the sort manipulator, so that it can precisely repeat its unloading and sorting work. The combination of manipulator's zero position and step motor counting control puts an end to accumulating error in long time operation. A sort manipulator's design in the practice engineering has been proved to be correct and reliable.

Integrated acoustic and magnetic separation in microfluidic channels

DEFF Research Database (Denmark)

Adams, Jonathan; Thevoz, Patrick; Bruus, Henrik

2009-01-01

With a growing number of cell-based biotechnological applications, there is a need for particle separation systems capable of multiparameter separations at high purity and throughput, beyond what is presently offered by traditional methods including fluorescence activated cell sorting and column......-based magnetic separation. Toward this aim, we report on the integration of microfluidic acoustic and magnetic separation in a monolithic device for multiparameter particle separation. Using our device, we demonstrate high-purity separation of a multicomponent particle mixture at a throughput of up to 10...

Tracking heavy water (D₂O) incorporation for identifying and sorting active microbial cells

DEFF Research Database (Denmark)

Berry, David; Mader, Esther; Lee, Tae Kwon

2015-01-01

Microbial communities are essential to the function of virtually all ecosystems and eukaryotes, including humans. However, it is still a major challenge to identify microbial cells active under natural conditions in complex systems. In this study, we developed a new method to identify and sort ac...

Apportioning bacterial carbon source utilization in soil using 14 C isotope analysis of FISH-targeted bacterial populations sorted by fluorescence activated cell sorting (FACS): 14 C-FISH-FACS.

Science.gov (United States)

Gougoulias, Christos; Meade, Andrew; Shaw, Liz J

2018-02-19

An unresolved need in microbial ecology is methodology to enable quantitative analysis of in situ microbial substrate carbon use at the population level. Here, we evaluated if a novel combination of radiocarbon-labelled substrate tracing, fluorescence in situ hybridisation (FISH) and fluorescence-activated cell sorting (FACS) to sort the FISH-targeted population for quantification of incorporated radioactivity ( 14 C-FISH-FACS) can address this need. Our test scenario used FISH probe PSE1284 targeting Pseudomonas spp. (and some Burkholderia spp.) and salicylic acid added to rhizosphere soil. We examined salicylic acid- 14 C fate (mineralized, cell-incorporated, extractable and non-extractable) and mass balance (0-24 h) and show that the PSE1284 population captured ∼ 50% of the Nycodenz extracted biomass 14 C. Analysis of the taxonomic distribution of the salicylic acid biodegradation trait suggested that PSE1284 population success was not due to conservation of this trait but due to competitiveness for the added carbon. Adding 50KBq of 14 C sample -1 enabled detection of 14 C in the sorted population at ∼ 60-600 times background; a sensitivity which demonstrates potential extension to analysis of rarer/less active populations. Given its sensitivity and compatibility with obtaining a C mass balance, 14 C-FISH-FACS allows quantitative dissection of C flow within the microbial biomass that has hitherto not been achieved. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

Advanced research on separating prostate cancer stem cells

International Nuclear Information System (INIS)

Hao Yumei; He Xin; Song Naling

2013-01-01

Prostate cancer is a common malignant tumor in male urinary system,and may easily develop into the hormone refractory prostate cancer which can hardly be cured. Recent studies had found that the prostate cancer stem cells may be the source of the prostate cancer's occurrence,development, metastasis and recurrence. The therapy targeting the prostate cancer stem cells may be the effective way to cure prostate cancer. But these cells is too low to be detected. The difficulty lies in the low separation efficiency of prostate cancer stem cell, so the effectively separating prostate cancer stem cells occupied the main position for the more in-depth research of prostate cancer stem cells. This paper reviews the research progress and existing problems on the several main separating methods of prostate cancer stem cells, includes the fluorescence activated cells sorting and magnetic activated cells sorting based on prostate cancer stem cell surface markers, the side-population sorting and serum-free medium sphere forming sorting based on prostate cancer stem cell's biology. (authors)

Parallel sorting algorithms

CERN Document Server

Akl, Selim G

1985-01-01

Parallel Sorting Algorithms explains how to use parallel algorithms to sort a sequence of items on a variety of parallel computers. The book reviews the sorting problem, the parallel models of computation, parallel algorithms, and the lower bounds on the parallel sorting problems. The text also presents twenty different algorithms, such as linear arrays, mesh-connected computers, cube-connected computers. Another example where algorithm can be applied is on the shared-memory SIMD (single instruction stream multiple data stream) computers in which the whole sequence to be sorted can fit in the

The Role of the Clathrin Adaptor AP-1: Polarized Sorting and Beyond

Directory of Open Access Journals (Sweden)

Fubito Nakatsu

2014-11-01

Full Text Available The selective transport of proteins or lipids by vesicular transport is a fundamental process supporting cellular physiology. The budding process involves cargo sorting and vesicle formation at the donor membrane and constitutes an important process in vesicular transport. This process is particularly important for the polarized sorting in epithelial cells, in which the cargo molecules need to be selectively sorted and transported to two distinct destinations, the apical or basolateral plasma membrane. Adaptor protein (AP-1, a member of the AP complex family, which includes the ubiquitously expressed AP-1A and the epithelium-specific AP-1B, regulates polarized sorting at the trans-Golgi network and/or at the recycling endosomes. A growing body of evidence, especially from studies using model organisms and animals, demonstrates that the AP-1-mediated polarized sorting supports the development and physiology of multi-cellular units as functional organs and tissues (e.g., cell fate determination, inflammation and gut immune homeostasis. Furthermore, a possible involvement of AP-1B in the pathogenesis of human diseases, such as Crohn’s disease and cancer, is now becoming evident. These data highlight the significant contribution of AP-1 complexes to the physiology of multicellular organisms, as master regulators of polarized sorting in epithelial cells.

Cellular transfer of magnetic nanoparticles via cell microvesicles: impact on cell tracking by magnetic resonance imaging.

Science.gov (United States)

Silva, Amanda K Andriola; Wilhelm, Claire; Kolosnjaj-Tabi, Jelena; Luciani, Nathalie; Gazeau, Florence

2012-05-01

Cell labeling with magnetic nanoparticles can be used to monitor the fate of transplanted cells in vivo by magnetic resonance imaging. However, nanoparticles initially internalized in administered cells might end up in other cells of the host organism. We investigated a mechanism of intercellular cross-transfer of magnetic nanoparticles to different types of recipient cells via cell microvesicles released under cellular stress. Three cell types (mesenchymal stem cells, endothelial cells and macrophages) were labeled with 8-nm iron oxide nanoparticles. Then cells underwent starvation stress, during which they produced microvesicles that were subsequently transferred to unlabeled recipient cells. The analysis of the magnetophoretic mobility of donor cells indicated that magnetic load was partially lost under cell stress. Microvesicles shed by stressed cells participated in the release of magnetic label. Moreover, such microvesicles were uptaken by naïve cells, resulting in cellular redistribution of nanoparticles. Iron load of recipient cells allowed their detection by MRI. Cell microvesicles released under stress may be disseminated throughout the organism, where they can be uptaken by host cells. The transferred cargo may be sufficient to allow MRI detection of these secondarily labeled cells, leading to misinterpretations of the effectiveness of transplanted cells.

Lipid phosphate phosphatase activity regulates dispersal and bilateral sorting of embryonic germ cells in Drosophila

Science.gov (United States)

Renault, Andrew D.; Kunwar, Prabhat S.; Lehmann, Ruth

2010-01-01

In Drosophila, germ cell survival and directionality of migration are controlled by two lipid phosphate phosphatases (LPP), wunen (wun) and wunen-2 (wun2). wun wun2 double mutant analysis reveals that the two genes, hereafter collectively called wunens, act redundantly in primordial germ cells. We find that wunens mediate germ cell-germ cell repulsion and that this repulsion is necessary for germ cell dispersal and proper transepithelial migration at the onset of migration and for the equal sorting of the germ cells between the two embryonic gonads during their migration. We propose that this dispersal function optimizes adult fecundity by assuring maximal germ cell occupancy of both gonads. Furthermore, we find that the requirement for wunens in germ cell survival can be eliminated by blocking germ cell migration. We suggest that this essential function of Wunen is needed to maintain cell integrity in actively migrating germ cells. PMID:20431117

What is a Sorting Function?

DEFF Research Database (Denmark)

Henglein, Fritz

2009-01-01

What is a sorting function—not a sorting function for a given ordering relation, but a sorting function with nothing given? Formulating four basic properties of sorting algorithms as defining requirements, we arrive at intrinsic notions of sorting and stable sorting: A function is a sorting...... are derivable without compromising data abstraction. Finally we point out that stable sorting functions as default representations of ordering relations have the advantage of permitting linear-time sorting algorithms; inequality tests forfeit this possibility....... function if and only it is an intrinsically parametric permutation function. It is a stable sorting function if and only if it is an intrinsically stable permutation function. We show that ordering relations can be represented isomorphically as inequality tests, comparators and stable sorting functions...

Dipeptidyl peptidase IV is sorted to the secretory granules in pancreatic islet A-cells

DEFF Research Database (Denmark)

Poulsen, Mona Dam; Hansen, Gert Helge; Dabelsteen, Erik

1993-01-01

Dipeptidyl peptidase IV (DP IV:EC 3.4.14.5) was localized in endocrine cells of pig pancreas by immunohistochemical and enzyme histochemical methods. Immunolight microscopy with both monoclonal and polyclonal antibodies demonstrated DP IV immunoreactivity in cells located in the peripheral part...... of the islets of Langerhans. The antigen is enzymatically active, as shown by enzyme histochemical analysis with a synthetic DP IV substrate. By immunoelectron microscopy (immunogold labeling), the labeling of DP IV in the islets was associated with the secretory granules of the A-cells, as identified by double...... labeling using a monoclonal glucagon antibody as the second primary antibody. These results show that DP IV is sorted to secretory granules in the pig pancreatic islet A-cells. Furthermore, this secretory granule enzyme, as opposed to intestinal brush border DP IV, is suggested to be a soluble protein...

Identification of residual leukemic cells by flow cytometry in childhood B-cell precursor acute lymphoblastic leukemia: verification of leukemic state by flow-sorting and molecular/cytogenetic methods.

Science.gov (United States)

Øbro, Nina F; Ryder, Lars P; Madsen, Hans O; Andersen, Mette K; Lausen, Birgitte; Hasle, Henrik; Schmiegelow, Kjeld; Marquart, Hanne V

2012-01-01

Reduction in minimal residual disease, measured by real-time quantitative PCR or flow cytometry, predicts prognosis in childhood B-cell precursor acute lymphoblastic leukemia. We explored whether cells reported as minimal residual disease by flow cytometry represent the malignant clone harboring clone-specific genomic markers (53 follow-up bone marrow samples from 28 children with B-cell precursor acute lymphoblastic leukemia). Cell populations (presumed leukemic and non-leukemic) were flow-sorted during standard flow cytometry-based minimal residual disease monitoring and explored by PCR and/or fluorescence in situ hybridization. We found good concordance between flow cytometry and genomic analyses in the individual flow-sorted leukemic (93% true positive) and normal (93% true negative) cell populations. Four cases with discrepant results had plausible explanations (e.g. partly informative immunophenotype and antigen modulation) that highlight important methodological pitfalls. These findings demonstrate that with sufficient experience, flow cytometry is reliable for minimal residual disease monitoring in B-cell precursor acute lymphoblastic leukemia, although rare cases require supplementary PCR-based monitoring.

Modeling the efficiency of a magnetic needle for collecting magnetic cells

International Nuclear Information System (INIS)

Butler, Kimberly S; Lovato, Debbie M; Larson, Richard S; Adolphi, Natalie L; Bryant, H C; Flynn, Edward R

2014-01-01

As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in (1) glycerine–water solutions, chosen to approximate the range of viscosities of bone marrow, and (2) water in which 3, 5, 10 and 100% of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency versus time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium. (paper)

Modeling the efficiency of a magnetic needle for collecting magnetic cells

Science.gov (United States)

Butler, Kimberly S.; Adolphi, Natalie L.; Bryant, H. C.; Lovato, Debbie M.; Larson, Richard S.; Flynn, Edward R.

2014-07-01

As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in (1) glycerine-water solutions, chosen to approximate the range of viscosities of bone marrow, and (2) water in which 3, 5, 10 and 100% of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency versus time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium.

T2-weighted four dimensional magnetic resonance imaging with result-driven phase sorting

International Nuclear Information System (INIS)

Liu, Yilin; Yin, Fang-Fang; Cai, Jing; Czito, Brian G.; Bashir, Mustafa R.

2015-01-01

Purpose: T2-weighted MRI provides excellent tumor-to-tissue contrast for target volume delineation in radiation therapy treatment planning. This study aims at developing a novel T2-weighted retrospective four dimensional magnetic resonance imaging (4D-MRI) phase sorting technique for imaging organ/tumor respiratory motion. Methods: A 2D fast T2-weighted half-Fourier acquisition single-shot turbo spin-echo MR sequence was used for image acquisition of 4D-MRI, with a frame rate of 2–3 frames/s. Respiratory motion was measured using an external breathing monitoring device. A phase sorting method was developed to sort the images by their corresponding respiratory phases. Besides, a result-driven strategy was applied to effectively utilize redundant images in the case when multiple images were allocated to a bin. This strategy, selecting the image with minimal amplitude error, will generate the most representative 4D-MRI. Since we are using a different image acquisition mode for 4D imaging (the sequential image acquisition scheme) with the conventionally used cine or helical image acquisition scheme, the 4D dataset sufficient condition was not obviously and directly predictable. An important challenge of the proposed technique was to determine the number of repeated scans (N_R) required to obtain sufficient phase information at each slice position. To tackle this challenge, the authors first conducted computer simulations using real-time position management respiratory signals of the 29 cancer patients under an IRB-approved retrospective study to derive the relationships between N_R and the following factors: number of slices (N_S), number of 4D-MRI respiratory bins (N_B), and starting phase at image acquisition (P_0). To validate the authors’ technique, 4D-MRI acquisition and reconstruction were simulated on a 4D digital extended cardiac-torso (XCAT) human phantom using simulation derived parameters. Twelve healthy volunteers were involved in an IRB-approved study

Robust spike sorting of retinal ganglion cells tuned to spot stimuli.

Science.gov (United States)

Ghahari, Alireza; Badea, Tudor C

2016-08-01

We propose an automatic spike sorting approach for the data recorded from a microelectrode array during visual stimulation of wild type retinas with tiled spot stimuli. The approach first detects individual spikes per electrode by their signature local minima. With the mixture probability distribution of the local minima estimated afterwards, it applies a minimum-squared-error clustering algorithm to sort the spikes into different clusters. A template waveform for each cluster per electrode is defined, and a number of reliability tests are performed on it and its corresponding spikes. Finally, a divisive hierarchical clustering algorithm is used to deal with the correlated templates per cluster type across all the electrodes. According to the measures of performance of the spike sorting approach, it is robust even in the cases of recordings with low signal-to-noise ratio.

Dielectrophoresis microsystem with integrated flow cytometers for on-line monitoring of sorting efficiency

DEFF Research Database (Denmark)

Wang, Zhenyu; Hansen, Ole; Petersen, Peter Kalsen

2006-01-01

Dielectrophoresis (DEP) and flow cytometry are powerful technologies and widely applied in microfluidic systems for handling and measuring cells and particles. Here, we present a novel microchip with a DEP selective filter integrated with two microchip flow cytometers (FCs) for on-line monitoring...... of cell sorting processes. On the microchip, the DEP filter is integrated in a microfluidic channel network to sort yeast cells by positive DER The two FCs detection windows are set upstream and downstream of the DEP filter. When a cell passes through the detection windows, the light scattered by the cell...

Flow cytogenetics and chromosome sorting.

Science.gov (United States)

Cram, L S

1990-06-01

This review of flow cytogenetics and chromosome sorting provides an overview of general information in the field and describes recent developments in more detail. From the early developments of chromosome analysis involving single parameter or one color analysis to the latest developments in slit scanning of single chromosomes in a flow stream, the field has progressed rapidly and most importantly has served as an important enabling technology for the human genome project. Technological innovations that advanced flow cytogenetics are described and referenced. Applications in basic cell biology, molecular biology, and clinical investigations are presented. The necessary characteristics for large number chromosome sorting are highlighted. References to recent review articles are provided as a starting point for locating individual references that provide more detail. Specific references are provided for recent developments.

Pleiotropic functions of magnetic nanoparticles for ex vivo gene transfer.

Science.gov (United States)

Kami, Daisuke; Kitani, Tomoya; Kishida, Tsunao; Mazda, Osam; Toyoda, Masashi; Tomitaka, Asahi; Ota, Satoshi; Ishii, Ryuga; Takemura, Yasushi; Watanabe, Masatoshi; Umezawa, Akihiro; Gojo, Satoshi

2014-08-01

Gene transfer technique has various applications, ranging from cellular biology to medical treatments for diseases. Although nonviral vectors, such as episomal vectors, have been developed, it is necessary to improve their gene transfer efficacy. Therefore, we attempted to develop a highly efficient gene delivery system combining an episomal vector with magnetic nanoparticles (MNPs). In comparison with the conventional method using transfection reagents, polyethylenimine-coated MNPs introduced episomal vectors more efficiently under a magnetic field and could express the gene in mammalian cells with higher efficiency and for longer periods. This novel in vitro separation method of gene-introduced cells utilizing the magnetic property of MNPs significantly facilitated the separation of cells of interest. Transplanted cells in vivo were detected using magnetic resonance. These results suggest that MNPs play multifunctional roles in ex vivo gene transfer, such as improvement of gene transfer efficacy, separation of cells, and detection of transplanted cells. This study convincingly demonstrates enhanced efficiency of gene transfer via magnetic nanoparticles. The method also enables magnetic sorting of cells positive for the transferred gene, and in vivo monitoring of the process with MRI. Copyright © 2014 Elsevier Inc. All rights reserved.

Ready, steady, SORT!

CERN Document Server

Laëtitia Pedroso

2010-01-01

The selective or ecological sorting of waste is already second nature to many of us and concerns us all. As the GS Department's new awareness-raising campaign reminds us, everything we do to sort waste contributes to preserving the environment.    Placemats printed on recycled paper using vegetable-based ink will soon be distributed in Restaurant No.1.   Environmental protection is never far from the headlines, and CERN has a responsibility to ensure that the 3000 tonnes and more of waste it produces every year are correctly and selectively sorted. Materials can be given a second life through recycling and re-use, thereby avoiding pollution from landfill sites and incineration plants and saving on processing costs. The GS Department is launching a new poster campaign designed to raise awareness of the importance of waste sorting and recycling. "After conducting a survey to find out whether members of the personnel were prepared to make an effort to sort a...

Validation of interphase fluorescence in situ hybridization (iFISH for multiple myeloma using CD138 positive cells

Directory of Open Access Journals (Sweden)

Renata Kiyomi Kishimoto

2016-06-01

Full Text Available ABSTRACT BACKGROUND: Multiple myeloma is a plasma cell neoplasm with acquired genetic abnormalities of clinical and prognostic importance. Multiple myeloma differs from other hematologic malignancies due to a high fraction of low proliferating malignant plasma cells and the paucity of plasma cells in bone marrow aspiration samples, making cytogenetic analysis a challenge. An abnormal karyotype is found in only one-third of patients with multiple myeloma and interphase fluorescence in situ hybridization is the most useful test for studying the chromosomal abnormalities present in almost 90% of cases. However, it is necessary to study the genetic abnormalities in plasma cells after their identification or selection by morphology, immunophenotyping or sorting. Other challenges are the selection of the most informative FISH panel and determining cut-off levels for FISH probes. This study reports the validation of interphase fluorescence in situ hybridization using CD138 positive cells, according to proposed guidelines published by the European Myeloma Network (EMN in 2012. METHOD: Bone marrow samples from patients with multiple myeloma were used to standardize a panel of five probes [1q amplification, 13q14 deletion, 17p deletion, t(4;14, and t(14;16] in CD138+ cells purified by magnetic cell sorting. RESULTS: This test was validated with a low turnaround time and good reproducibility. Five of six samples showed genetic abnormalities. Monosomy/deletion 13 plus t(4;14 were found in two cases. CONCLUSION: This technique together with magnetic cell sorting is effective and can be used in the routine laboratory practice. In addition, magnetic cell sorting provides a pure plasma cell population that allows other molecular and genomic studies.

An extensible infrastructure for fully automated spike sorting during online experiments.

Science.gov (United States)

Santhanam, Gopal; Sahani, Maneesh; Ryu, Stephen; Shenoy, Krishna

2004-01-01

When recording extracellular neural activity, it is often necessary to distinguish action potentials arising from distinct cells near the electrode tip, a process commonly referred to as "spike sorting." In a number of experiments, notably those that involve direct neuroprosthetic control of an effector, this cell-by-cell classification of the incoming signal must be achieved in real time. Several commercial offerings are available for this task, but all of these require some manual supervision per electrode, making each scheme cumbersome with large electrode counts. We present a new infrastructure that leverages existing unsupervised algorithms to sort and subsequently implement the resulting signal classification rules for each electrode using a commercially available Cerebus neural signal processor. We demonstrate an implementation of this infrastructure to classify signals from a cortical electrode array, using a probabilistic clustering algorithm (described elsewhere). The data were collected from a rhesus monkey performing a delayed center-out reach task. We used both sorted and unsorted (thresholded) action potentials from an array implanted in pre-motor cortex to "predict" the reach target, a common decoding operation in neuroprosthetic research. The use of sorted spikes led to an improvement in decoding accuracy of between 3.6 and 6.4%.

Cell cycle kinetics and in vivo micronuclei induction in rat rhabdomyosarcoma tumors using a monoclonal antibody to BrdUrd and cell sorting

International Nuclear Information System (INIS)

Nuesse, M.; Afzal, S.M.J.; Carr, B.C.; Kavanau, K.S.; Tenforde, T.S.; Curtis, S.B.

1986-01-01

The aim of the experiments reported here was to investigate the applicability of the BrdUrd/DNA technique to a rat rhabdomyosarcoma tumor system growing in vivo and to study radiation-induced changes in the progression of cells through the cell cycle. Details of this technique are described elsewhere. In addition, the induction of micronuclei in tumor cells irradiated in vivo with x-rays or peak neon ions was studied. Micronuclei found in interphase cells after irradiation represent genetic material that is lost from the genome of the cells during mitosis. The formation of micronuclei that can mainly be ascribed to acentric chromosome or chromatid fragments occurs only after cells go through one or more cell divisions. Cycling cells in the tumors were, therefore, continuously labeled with BrdUrd, and micronuclei induction was measured only in tetraploid cycling tumor cells using the flow cytometric cell sorting technique

Bone Marrow Regeneration Promoted by Biophysically Sorted Osteoprogenitors From Mesenchymal Stromal Cells

Science.gov (United States)

Poon, Zhiyong; Lee, Wong Cheng; Guan, Guofeng; Nyan, Lin Myint; Lim, Chwee Teck; Han, Jongyoon

2015-01-01

Human tissue repair deficiencies can be supplemented through strategies to isolate, expand in vitro, and reimplant regenerative cells that supplant damaged cells or stimulate endogenous repair mechanisms. Bone marrow-derived mesenchymal stromal cells (MSCs), a subset of which is described as mesenchymal stem cells, are leading candidates for cell-mediated bone repair and wound healing, with hundreds of ongoing clinical trials worldwide. An outstanding key challenge for successful clinical translation of MSCs is the capacity to produce large quantities of cells in vitro with uniform and relevant therapeutic properties. By leveraging biophysical traits of MSC subpopulations and label-free microfluidic cell sorting, we hypothesized and experimentally verified that MSCs of large diameter within expanded MSC cultures were osteoprogenitors that exhibited significantly greater efficacy over other MSC subpopulations in bone marrow repair. Systemic administration of osteoprogenitor MSCs significantly improved survival rates (>80%) as compared with other MSC subpopulations (0%) for preclinical murine bone marrow injury models. Osteoprogenitor MSCs also exerted potent therapeutic effects as “cell factories” that secreted high levels of regenerative factors such as interleukin-6 (IL-6), interleukin-8 (IL-8), vascular endothelial growth factor A, bone morphogenetic protein 2, epidermal growth factor, fibroblast growth factor 1, and angiopoietin-1; this resulted in increased cell proliferation, vessel formation, and reduced apoptosis in bone marrow. This MSC subpopulation mediated rescue of damaged marrow tissue via restoration of the hematopoiesis-supporting stroma, as well as subsequent hematopoiesis. Together, the capabilities described herein for label-freeisolation of regenerative osteoprogenitor MSCs can markedly improve the efficacy of MSC-based therapies. PMID:25411477

Uptake of magnetic nanoparticles into cells for cell tracking

International Nuclear Information System (INIS)

Becker, Christiane; Hodenius, Michael; Blendinger, Gitta; Sechi, Antonio; Hieronymus, Thomas; Mueller-Schulte, Detlef; Schmitz-Rode, Thomas; Zenke, Martin

2007-01-01

A challenge for future applications in nanotechnology is the functional integration of nano-sized materials into cellular structures. Here we investigated superparamagnetic Fe 3 O 4 iron oxide nanoparticles coated with a lipid bilayer for uptake into cells and for targeting subcellular compartments. It was found that magnetic nanoparticles (MNPs) are effectively taken up into cells and make cells acquire magnetic activity. Biotin-conjugated MNPs were further functionalized by binding of the fluorescent tag streptavidin-fluorescein isothiocyanate (FITC) and, following uptake into cells, shown to confer magnetic activity and fluorescence labeling. Such FITC-MNPs were localized in the lysosomal compartment of cells which suggests a receptor-mediated uptake mechanism

Sorting a distribution theory

CERN Document Server

Mahmoud, Hosam M

2011-01-01

A cutting-edge look at the emerging distributional theory of sorting Research on distributions associated with sorting algorithms has grown dramatically over the last few decades, spawning many exact and limiting distributions of complexity measures for many sorting algorithms. Yet much of this information has been scattered in disparate and highly specialized sources throughout the literature. In Sorting: A Distribution Theory, leading authority Hosam Mahmoud compiles, consolidates, and clarifies the large volume of available research, providing a much-needed, comprehensive treatment of the

Magnetic apatite for structural insights on the plasma membrane

International Nuclear Information System (INIS)

Stanca, Sarmiza E; Müller, Robert; Dellith, Jan; Deckert, Volker; Krafft, Christoph; Popp, Jürgen; Fritzsche, Wolfgang; Nietzsche, Sandor; Stöckel, Stephan; Biskup, Christoph

2015-01-01

The iron oxide-hydroxyapatite (FeOxHA) nanoparticles reported here differ from those reported before by their advantage of homogeneity and simple preparation; moreover, the presence of carboxymethyldextran (CMD), together with hydroxyapatite (HA), allows access to the cellular membrane, which makes our magnetic apatite unique. These nanoparticles combine magnetic behavior, Raman label ability and the property of interaction with the cellular membrane; they therefore represent an interesting material for structural differentiation of the cell membrane. It was observed by Raman spectroscopy, scanning electron microscopy (SEM) and fluorescence microscopy that FeOxHA adheres to the plasma membrane and does not penetrate the membrane. These insights make the nanoparticles a promising material for magnetic cell sorting, e.g. in microfluidic device applications. (paper)

Magnetic apatite for structural insights on the plasma membrane

Science.gov (United States)

Stanca, Sarmiza E.; Müller, Robert; Dellith, Jan; Nietzsche, Sandor; Stöckel, Stephan; Biskup, Christoph; Deckert, Volker; Krafft, Christoph; Popp, Jürgen; Fritzsche, Wolfgang

2015-01-01

The iron oxide-hydroxyapatite (FeOxHA) nanoparticles reported here differ from those reported before by their advantage of homogeneity and simple preparation; moreover, the presence of carboxymethyldextran (CMD), together with hydroxyapatite (HA), allows access to the cellular membrane, which makes our magnetic apatite unique. These nanoparticles combine magnetic behavior, Raman label ability and the property of interaction with the cellular membrane; they therefore represent an interesting material for structural differentiation of the cell membrane. It was observed by Raman spectroscopy, scanning electron microscopy (SEM) and fluorescence microscopy that FeOxHA adheres to the plasma membrane and does not penetrate the membrane. These insights make the nanoparticles a promising material for magnetic cell sorting, e.g. in microfluidic device applications.

Identification of microbes from the surfaces of food-processing lines based on the flow cytometric evaluation of cellular metabolic activity combined with cell sorting.

Science.gov (United States)

Juzwa, W; Duber, A; Myszka, K; Białas, W; Czaczyk, K

2016-09-01

In this study the design of a flow cytometry-based procedure to facilitate the detection of adherent bacteria from food-processing surfaces was evaluated. The measurement of the cellular redox potential (CRP) of microbial cells was combined with cell sorting for the identification of microorganisms. The procedure enhanced live/dead cell discrimination owing to the measurement of the cell physiology. The microbial contamination of the surface of a stainless steel conveyor used to process button mushrooms was evaluated in three independent experiments. The flow cytometry procedure provided a step towards monitoring of contamination and enabled the assessment of microbial food safety hazards by the discrimination of active, mid-active and non-active bacterial sub-populations based on determination of their cellular vitality and subsequently single cell sorting to isolate microbial strains from discriminated sub-populations. There was a significant correlation (r = 0.97; p vitality and the identification of species from defined sub-populations, although the identified microbes were limited to culturable cells.

Separation of active and inactive fractions from starved culture of Vibrio parahaemolyticus by density dependent cell sorting.

Science.gov (United States)

Nayak, Binaya Bhusan; Kamiya, Eriko; Nishino, Tomohiko; Wada, Minoru; Nishimura, Masahiko; Kogure, Kazuhiro

2005-01-01

The co-existence of physiologically different cells in bacterial cultures is a general phenomenon. We have examined the applicability of the density dependent cell sorting (DDCS) method to separate subpopulations from a long-term starvation culture of Vibrio parahaemolyticus. The cells were subjected to Percoll density gradient and separated into 12 fractions of different buoyant densities, followed by measuring the cell numbers, culturability, respiratory activity and leucine incorporation activity. While more than 78% of cells were in lighter fractions, about 95% of culturable cells were present in heavier fractions. The high-density subpopulations also had high proportion of cells capable of forming formazan granules. Although this was accompanied by the cell specific INT-reduction rate, both leucine incorporation rates and INT-reduction rates per cell had a peak at mid-density fraction. The present results indicated that DDCS could be used to separate subpopulations of different physiological conditions.

Magnetic Nanowires as Materials for Cancer Cell Destruction

KAUST Repository

Contreras, Maria F.

2015-12-01

Current cancer therapies are highly cytotoxic and their delivery to exclusively the affected site is poorly controlled, resulting in unavoidable and often severe side effects. In an effort to overcome such issues, magnetic nanoparticles have been recently gaining relevance in the areas of biomedical applications and therapeutics, opening pathways to alternative methods. This led to the concept of magnetic particle hyperthermia in which magnetic nano beads are heated by a high power magnetic field. The increase in temperature kills the cancer cells, which are more susceptible to heat in comparison to healthy cells. In this dissertation, the possibility to kill cancer cells with magnetic nanowires is evaluated. The idea is to exploit a magnetomechanical effect, where nanowires cause cancer cell death through vibrating in a low power magnetic field. Specifically, the magnetic nanowires effects to cells in culture and their ability to induce cancer cell death, when combined with an alternating magnetic field, was investigated. Nickel and iron nanowires of 35 nm diameter and 1 to 5 μm long were synthesized by electrodeposition into nanoporous alumina templates, which were prepared using a two-step anodization process on highly pure aluminum substrates. For the cytotoxicity studies, the nanowires were added to cancer cells in culture, varying the incubation time and the concentration. The cell-nanowire interaction was thoroughly studied at the cellular level (mitochondrial metabolic activity, cell membrane integrity and, apoptosis/necrosis assay), and optical level (transmission electron and confocal microscopy). Furthermore, to investigate their therapeutic potential, an alternating magnetic field was applied varying its intensity and frequency. After the magnetic field application, cells health was measured at the mitochondrial activity level. Cytotoxicity results shed light onto the cellular tolerance to the nanowires, which helped in establishing the appropriate

Effect of climate on morphology and development of sorted circles and polygons

Czech Academy of Sciences Publication Activity Database

Uxa, Tomáš; Mida, P.; Křížek, M.

2017-01-01

Roč. 28, č. 4 (2017), s. 663-674 ISSN 1045-6740 Institutional support: RVO:67985530 Keywords : patterned ground * sorted circles and polygons * morphology * active layer * Svalbard * high Arctic Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Physical geography Impact factor: 2.815, year: 2016

Targeting to carcinoma cells with chitosan- and starch-coated magnetic nanoparticles for magnetic hyperthermia.

Science.gov (United States)

Kim, Dong-Hyun; Kim, Kyoung-Nam; Kim, Kwang-Mahn; Lee, Yong-Keun

2009-01-01

The delivery of hyperthermic thermoseeds to a specific target site with minimal side effects is an important challenge in targeted hyperthermia, which employs magnetic method and functional polymers. An external magnetic field is used to control the site-specific targeting of the magnetic nanoparticles. Polymer-coated magnetic nanoparticles can confer a higher affinity to the biological cell membranes. In this study, uncoated, chitosan-coated, and starch-coated magnetic nanoparticles were synthesized for use as a hyperthermic thermoseed. Each sample was examined with respect to their applications to hyperthermia using XRD, VSM, and FTIR. In addition, the temperature changes under an alternating magnetic field were observed. As in vitro tests, the magnetic responsiveness of chitosan- and starch-coated magnetite was determined by a simple blood vessel model under various intensities of magnetic field. L929 normal cells and KB carcinoma cells were used to examine the cytotoxicity and affinity of each sample using the MTT method. The chitosan-coated magnetic nanoparticles generated a higher DeltaT of 23 degrees C under an AC magnetic field than the starch-coated magnetite, and the capturing rate of the particles was 96% under an external magnetic field of 0.4 T. The highest viability of L929 cells was 93.7%. Comparing the rate of KB cells capture with the rate of L929 cells capture, the rate of KB cells capture relatively increased with 10.8% in chitosan-coated magnetic nanoparticles. Hence, chitosan-coated magnetic nanoparticles are biocompatible and have a selective affinity to KB cells. The targeting of magnetic nanoparticles in hyperthermia was improved using a controlled magnetic field and a chitosan-coating. Therefore, chitosan-coated magnetic nanoparticles are expected to be promising materials for use in magnetic targeted hyperthermia. 2008 Wiley Periodicals, Inc.

Microfluidic high gradient magnetic cell separation

Science.gov (United States)

Inglis, David W.; Riehn, Robert; Sturm, James C.; Austin, Robert H.

2006-04-01

Separation of blood cells by native susceptibility and by the selective attachment of magnetic beads has recently been demonstrated on microfluidic devices. We discuss the basic principles of how forces are generated via the magnetic susceptibility of an object and how microfluidics can be combined with micron-scale magnetic field gradients to greatly enhance in principle the fractionating power of magnetic fields. We discuss our efforts and those of others to build practical microfluidic devices for the magnetic separation of blood cells. We also discuss our attempts to integrate magnetic separation with other microfluidic features for developing handheld medical diagnostic tools.

Expression analysis of Arabidopsis vacuolar sorting receptor 3 reveals a putative function in guard cells.

Science.gov (United States)

Avila, Emily L; Brown, Michelle; Pan, Songqin; Desikan, Radhika; Neill, Steven J; Girke, Thomas; Surpin, Marci; Raikhel, Natasha V

2008-01-01

Vacuolar sorting receptors (VSRs) are responsible for the proper targeting of soluble cargo proteins to their destination compartments. The Arabidopsis genome encodes seven VSRs. In this work, the spatio-temporal expression of one of the members of this gene family, AtVSR3, was determined by RT-PCR and promoter::reporter gene fusions. AtVSR3 was expressed specifically in guard cells. Consequently, a reverse genetics approach was taken to determine the function of AtVSR3 by using RNA interference (RNAi) technology. Plants expressing little or no AtVSR3 transcript had a compressed life cycle, bolting approximately 1 week earlier and senescing up to 2 weeks earlier than the wild-type parent line. While the development and distribution of stomata in AtVSR3 RNAi plants appeared normal, stomatal function was altered. The guard cells of mutant plants did not close in response to abscisic acid treatment, and the mean leaf temperatures of the RNAi plants were on average 0.8 degrees C lower than both wild type and another vacuolar sorting receptor mutant, atvsr1-1. Furthermore, the loss of AtVSR3 protein caused the accumulation of nitric oxide and hydrogen peroxide, signalling molecules implicated in the regulation of stomatal opening and closing. Finally, proteomics and western blot analyses of cellular proteins isolated from wild-type and AtVSR3 RNAi leaves showed that phospholipase Dgamma, which may play a role in abscisic acid signalling, accumulated to higher levels in AtVSR3 RNAi guard cells. Thus, AtVSR3 may play an important role in responses to plant stress.

A degradation-based sorting method for lithium-ion battery reuse.

Directory of Open Access Journals (Sweden)

Hao Chen

Full Text Available In a world where millions of people are dependent on batteries to provide them with convenient and portable energy, battery recycling is of the utmost importance. In this paper, we developed a new method to sort 18650 Lithium-ion batteries in large quantities and in real time for harvesting used cells with enough capacity for battery reuse. Internal resistance and capacity tests were conducted as a basis for comparison with a novel degradation-based method based on X-ray radiographic scanning and digital image contrast computation. The test results indicate that the sorting accuracy of the test cells is about 79% and the execution time of our algorithm is at a level of 200 milliseconds, making our method a potential real-time solution for reusing the remaining capacity in good used cells.

Wage Sorting Trends

DEFF Research Database (Denmark)

Bagger, Jesper; Vejlin, Rune Majlund; Sørensen, Kenneth Lykke

Using a population-wide Danish Matched Employer-Employee panel from 1980-2006, we document a strong trend towards more positive assortative wage sorting. The correlation between worker and firm fixed effects estimated from a log wage regression increases from -0.07 in 1981 to .14 in 2001. The non......Using a population-wide Danish Matched Employer-Employee panel from 1980-2006, we document a strong trend towards more positive assortative wage sorting. The correlation between worker and firm fixed effects estimated from a log wage regression increases from -0.07 in 1981 to .14 in 2001....... The nonstationary wage sorting pattern is not due to compositional changes in the labor market, primarily occurs among high wage workers, and comprises 41 percent of the increase in the standard deviation of log real wages between 1980 and 2006. We show that the wage sorting trend is associated with worker...

Cell-cycle synchronisation of bloodstream forms of Trypanosoma brucei using Vybrant DyeCycle Violet-based sorting.

Science.gov (United States)

Kabani, Sarah; Waterfall, Martin; Matthews, Keith R

2010-01-01

Studies on the cell-cycle of Trypanosoma brucei have revealed several unusual characteristics that differ from the model eukaryotic organisms. However, the inability to isolate homogenous populations of parasites in distinct cell-cycle stages has limited the analysis of trypanosome cell division and complicated the understanding of mutant phenotypes with possible impact on cell-cycle related events. Although hydroxyurea-induced cell-cycle arrest in procyclic and bloodstream forms has been applied recently with success, such block-release protocols can complicate the analysis of cell-cycle regulated events and have the potential to disrupt important cell-cycle checkpoints. An alternative approach based on flow cytometry of parasites stained with Vybrant DyeCycle Orange circumvents this problem, but is restricted to procyclic form parasites. Here, we apply Vybrant Dyecycle Violet staining coupled with flow cytometry to effectively select different cell-cycle stages of bloodstream form trypanosomes. Moreover, the sorted parasites remain viable, although synchrony is rapidly lost. This method enables cell-cycle enrichment of populations of trypanosomes in their mammal infective stage, particularly at the G1 phase.

Ore sorting

International Nuclear Information System (INIS)

Hawkins, A.P.; Richards, A.W.

1982-01-01

In an ore sorting apparatus, ore particles are bombarded with neutrons in a chamber and sorted by detecting radiation emitted by isotopes of elements, such as gold, forming or contained in the particles, using detectors and selectively controlling fluid jets. The isotopes can be selectively recognised by their radiation characteristics. In an alternative embodiment, shorter life isotopes are formed by neutron bombardment and detection of radiation takes place immediately adjacent the region of bombardment

Advanced optimization of permanent magnet wigglers using a genetic algorithm

Energy Technology Data Exchange (ETDEWEB)

Hajima, Ryoichi [Univ. of Tokyo (Japan)

1995-12-31

In permanent magnet wigglers, magnetic imperfection of each magnet piece causes field error. This field error can be reduced or compensated by sorting magnet pieces in proper order. We showed a genetic algorithm has good property for this sorting scheme. In this paper, this optimization scheme is applied to the case of permanent magnets which have errors in the direction of field. The result shows the genetic algorithm is superior to other algorithms.

Advanced optimization of permanent magnet wigglers using a genetic algorithm

International Nuclear Information System (INIS)

Hajima, Ryoichi

1995-01-01

In permanent magnet wigglers, magnetic imperfection of each magnet piece causes field error. This field error can be reduced or compensated by sorting magnet pieces in proper order. We showed a genetic algorithm has good property for this sorting scheme. In this paper, this optimization scheme is applied to the case of permanent magnets which have errors in the direction of field. The result shows the genetic algorithm is superior to other algorithms

Inhibition of heat-shock protein 90 sensitizes liver cancer stem-like cells to magnetic hyperthermia and enhances anti-tumor effect on hepatocellular carcinoma-burdened nude mice

Science.gov (United States)

Yang, Rui; Tang, Qiusha; Miao, Fengqin; An, Yanli; Li, Mengfei; Han, Yong; Wang, Xihui; Wang, Juan; Liu, Peidang; Chen, Rong

2015-01-01

Purpose To explore the thermoresistance and expression of heat-shock protein 90 (HSP90) in magnetic hyperthermia-treated human liver cancer stem-like cells (LCSCs) and the effects of a heat-shock protein HSP90 inhibitor 17-allylamino-17-demethoxgeldanamycin (17-AAG) on hepatocellular carcinoma-burdened nude mice. Methods CD90+ LCSCs were isolated by magnetic-activated cell sorting from BEL-7404. Spheroid formation, proliferation, differentiation, drug resistance, and tumor formation assays were performed to identify stem cell characteristics. CD90-targeted thermosensitive magnetoliposomes (TMs)-encapsulated 17-AAG (CD90@17-AAG/TMs) was prepared by reverse-phase evaporation and its characteristics were studied. Heat tolerance in CD90+ LCSCs and the effect of CD90@17-AAG/TMs-mediated heat sensitivity were examined in vitro and in vivo. Results CD90+ LCSCs showed significant stem cell-like properties. The 17-AAG/TMs were successfully prepared and were spherical in shape with an average size of 128.9±7.7 nm. When exposed to magnetic hyperthermia, HSP90 was up-regulated in CD90+ LCSCs. CD90@17-AAG/TMs inhibited the activity of HSP90 and increased the sensitivity of CD90+ LCSCs to magnetic hyperthermia. Conclusion The inhibition of HSP90 could sensitize CD90+ LCSCs to magnetic hyperthermia and enhance its anti-tumor effects in vitro and in vivo. PMID:26677324

Improved methods for reprogramming human dermal fibroblasts using fluorescence activated cell sorting.

Directory of Open Access Journals (Sweden)

David J Kahler

Full Text Available Current methods to derive induced pluripotent stem cell (iPSC lines from human dermal fibroblasts by viral infection rely on expensive and lengthy protocols. One major factor contributing to the time required to derive lines is the ability of researchers to identify fully reprogrammed unique candidate clones from a mixed cell population containing transformed or partially reprogrammed cells and fibroblasts at an early time point post infection. Failure to select high quality colonies early in the derivation process results in cell lines that require increased maintenance and unreliable experimental outcomes. Here, we describe an improved method for the derivation of iPSC lines using fluorescence activated cell sorting (FACS to isolate single cells expressing the cell surface marker signature CD13(NEGSSEA4(POSTra-1-60(POS on day 7-10 after infection. This technique prospectively isolates fully reprogrammed iPSCs, and depletes both parental and "contaminating" partially reprogrammed fibroblasts, thereby substantially reducing the time and reagents required to generate iPSC lines without the use of defined small molecule cocktails. FACS derived iPSC lines express common markers of pluripotency, and possess spontaneous differentiation potential in vitro and in vivo. To demonstrate the suitability of FACS for high-throughput iPSC generation, we derived 228 individual iPSC lines using either integrating (retroviral or non- integrating (Sendai virus reprogramming vectors and performed extensive characterization on a subset of those lines. The iPSC lines used in this study were derived from 76 unique samples from a variety of tissue sources, including fresh or frozen fibroblasts generated from biopsies harvested from healthy or disease patients.

Continuous flow microfluidic separation and processing of rare cells and bioparticles found in blood – A review

DEFF Research Database (Denmark)

Antfolk, Maria; Laurell, Thomas

2017-01-01

conventional cell separation methods, such as flow cytometry or magnetic activated cell sorting, have fallen short other methods are desperately sought for. Microfluidics have been extensively used towards isolating and processing rare cells as it offers possibilities not present in the conventional systems...

Simple sorting algorithm test based on CUDA

OpenAIRE

Meng, Hongyu; Guo, Fangjin

2015-01-01

With the development of computing technology, CUDA has become a very important tool. In computer programming, sorting algorithm is widely used. There are many simple sorting algorithms such as enumeration sort, bubble sort and merge sort. In this paper, we test some simple sorting algorithm based on CUDA and draw some useful conclusions.

BayesMotif: de novo protein sorting motif discovery from impure datasets.

Science.gov (United States)

Hu, Jianjun; Zhang, Fan

2010-01-18

Protein sorting is the process that newly synthesized proteins are transported to their target locations within or outside of the cell. This process is precisely regulated by protein sorting signals in different forms. A major category of sorting signals are amino acid sub-sequences usually located at the N-terminals or C-terminals of protein sequences. Genome-wide experimental identification of protein sorting signals is extremely time-consuming and costly. Effective computational algorithms for de novo discovery of protein sorting signals is needed to improve the understanding of protein sorting mechanisms. We formulated the protein sorting motif discovery problem as a classification problem and proposed a Bayesian classifier based algorithm (BayesMotif) for de novo identification of a common type of protein sorting motifs in which a highly conserved anchor is present along with a less conserved motif regions. A false positive removal procedure is developed to iteratively remove sequences that are unlikely to contain true motifs so that the algorithm can identify motifs from impure input sequences. Experiments on both implanted motif datasets and real-world datasets showed that the enhanced BayesMotif algorithm can identify anchored sorting motifs from pure or impure protein sequence dataset. It also shows that the false positive removal procedure can help to identify true motifs even when there is only 20% of the input sequences containing true motif instances. We proposed BayesMotif, a novel Bayesian classification based algorithm for de novo discovery of a special category of anchored protein sorting motifs from impure datasets. Compared to conventional motif discovery algorithms such as MEME, our algorithm can find less-conserved motifs with short highly conserved anchors. Our algorithm also has the advantage of easy incorporation of additional meta-sequence features such as hydrophobicity or charge of the motifs which may help to overcome the limitations of

A Sorting Statistic with Application in Neurological Magnetic Resonance Imaging of Autism.

Science.gov (United States)

Levman, Jacob; Takahashi, Emi; Forgeron, Cynthia; MacDonald, Patrick; Stewart, Natalie; Lim, Ashley; Martel, Anne

2018-01-01

Effect size refers to the assessment of the extent of differences between two groups of samples on a single measurement. Assessing effect size in medical research is typically accomplished with Cohen's d statistic. Cohen's d statistic assumes that average values are good estimators of the position of a distribution of numbers and also assumes Gaussian (or bell-shaped) underlying data distributions. In this paper, we present an alternative evaluative statistic that can quantify differences between two data distributions in a manner that is similar to traditional effect size calculations; however, the proposed approach avoids making assumptions regarding the shape of the underlying data distribution. The proposed sorting statistic is compared with Cohen's d statistic and is demonstrated to be capable of identifying feature measurements of potential interest for which Cohen's d statistic implies the measurement would be of little use. This proposed sorting statistic has been evaluated on a large clinical autism dataset from Boston Children's Hospital , Harvard Medical School , demonstrating that it can potentially play a constructive role in future healthcare technologies.

Mean-cluster approach indicates cell sorting time scales are determined by collective dynamics

Science.gov (United States)

Beatrici, Carine P.; de Almeida, Rita M. C.; Brunnet, Leonardo G.

2017-03-01

Cell migration is essential to cell segregation, playing a central role in tissue formation, wound healing, and tumor evolution. Considering random mixtures of two cell types, it is still not clear which cell characteristics define clustering time scales. The mass of diffusing clusters merging with one another is expected to grow as td /d +2 when the diffusion constant scales with the inverse of the cluster mass. Cell segregation experiments deviate from that behavior. Explanations for that could arise from specific microscopic mechanisms or from collective effects, typical of active matter. Here we consider a power law connecting diffusion constant and cluster mass to propose an analytic approach to model cell segregation where we explicitly take into account finite-size corrections. The results are compared with active matter model simulations and experiments available in the literature. To investigate the role played by different mechanisms we considered different hypotheses describing cell-cell interaction: differential adhesion hypothesis and different velocities hypothesis. We find that the simulations yield normal diffusion for long time intervals. Analytic and simulation results show that (i) cluster evolution clearly tends to a scaling regime, disrupted only at finite-size limits; (ii) cluster diffusion is greatly enhanced by cell collective behavior, such that for high enough tendency to follow the neighbors, cluster diffusion may become independent of cluster size; (iii) the scaling exponent for cluster growth depends only on the mass-diffusion relation, not on the detailed local segregation mechanism. These results apply for active matter systems in general and, in particular, the mechanisms found underlying the increase in cell sorting speed certainly have deep implications in biological evolution as a selection mechanism.

Comprehensive Study of Microgel Electrode for On-Chip Electrophoretic Cell Sorting

Science.gov (United States)

Hattori, Akihiro; Yasuda, Kenji

2010-06-01

We have developed an on-chip cell sorting system and microgel electrode for applying electrostatic force in microfluidic pathways in the chip. The advantages of agarose electrodes are 1) current-driven electrostatic force generation, 2) stability against pH change and chemicals, and 3) no bubble formation caused by electrolysis. We examined the carrier ion type and concentration dependence of microgel electrode impedance, and found that CoCl2 has less than 1/10 of the impedance from NaCl, and the reduction of the impedance of NaCl gel electrode was plateaued at 0.5 M. The structure control of the microgel electrode exploiting the surface tension of sol-state agarose was also introduced. The addition of 1% (w/v) trehalose into the microgel electrode allowed the frozen storage of the microgel electrode chip. The experimental results demonstrate the potential of our system and microgel electrode for practical applications in microfluidic chips.

Layers in sorting practices: Sorting out patients with potential cancer

DEFF Research Database (Denmark)

Møller, Naja Holten; Bjørn, Pernille

2011-01-01

for a particular patient. Due to the limited resources within the Danish healthcare system, initiating cancer pathways for all patients with a remote suspicion of cancer would crash the system, as it would be impossible for healthcare professionals to commit to the prescribed schedules and times defined...... they show that sorting patients before initiating a standardized cancer pathway is not a simple process of deciding on a predefined category that will stipulate particular dates and times. Instead, these informal sorting mechanisms show that the process of sorting patients prior to diagnosis......In the last couple of years, widespread use of standardized cancer pathways has been seen across a range of countries, including Denmark, to improve prognosis of cancer patients. In Denmark, standardized cancer pathways take the form of guidelines prescribing well-defined sequences where steps...

Enrichment of putative pancreatic progenitor cells from mice by sorting for prominin1 (CD133) and platelet-derived growth factor receptor beta.

Science.gov (United States)

Hori, Yuichi; Fukumoto, Miki; Kuroda, Yoshikazu

2008-11-01

Success in islet transplantation-based therapies for type 1 diabetes mellitus and an extreme shortage of pancreatic islets have motivated recent efforts to develop renewable sources of islet-replacement tissue. Although pancreatic progenitor cells hold a promising potential, only a few attempts have been made at the prospective isolation of pancreatic stem/progenitor cells, because of the lack of specific markers and the development of effective cell culture methods. We found that prominin1 (also known as CD133) recognized the undifferentiated epithelial cells, whereas platelet-derived growth factor receptor beta (PDGFRbeta) was expressed on the mesenchymal cells in the mouse embryonic pancreas. We then developed an isolation method for putative stem/progenitor cells by flow cytometric cell sorting and characterized their potential for differentiation to pancreatic tissue using both in vitro and in vivo protocols. Flow cytometry and the subsequent reverse transcription-polymerase chain reaction and microarray analysis revealed pancreatic epithelial progenitor cells to be highly enriched in the prominin1(high)PDGFRbeta(-) cell population. During in vivo differentiation, these cell populations were able to differentiate into endocrine, exocrine, and ductal tissues, including the formation of an insulin-producing cell cluster. We established the prospective isolation of putative pancreatic epithelial progenitor cells by sorting for prominin1 and PDGFRbeta. Since this strategy is based on the cell surface markers common to human and rodents, these findings may lead to the development of new strategies to derive transplantable islet-replacement tissues from human pancreatic stem/progenitor cells. Disclosure of potential conflicts of interest is found at the end of this article.

A nanowire magnetic memory cell based on a periodic magnetic superlattice

International Nuclear Information System (INIS)

Song, J-F; Bird, J P; Ochiai, Y

2005-01-01

We analyse the operation of a semiconductor nanowire-based memory cell. Large changes in the nanowire conductance result when the magnetization of a periodic array of nanoscale magnetic gates, which comprise the other key component of the memory cell, is switched between distinct configurations by an external magnetic field. The resulting conductance change provides the basis for a robust memory effect, which can be implemented in a semiconductor structure compatible with conventional semiconductor integrated circuits

A multicenter study to standardize reporting and analyses of fluorescence-activated cell-sorted murine intestinal epithelial cells

Science.gov (United States)

Magness, Scott T.; Puthoff, Brent J.; Crissey, Mary Ann; Dunn, James; Henning, Susan J.; Houchen, Courtney; Kaddis, John S.; Kuo, Calvin J.; Li, Linheng; Lynch, John; Martin, Martin G.; May, Randal; Niland, Joyce C.; Olack, Barbara; Qian, Dajun; Stelzner, Matthias; Swain, John R.; Wang, Fengchao; Wang, Jiafang; Wang, Xinwei; Yan, Kelley; Yu, Jian

2013-01-01

Fluorescence-activated cell sorting (FACS) is an essential tool for studies requiring isolation of distinct intestinal epithelial cell populations. Inconsistent or lack of reporting of the critical parameters associated with FACS methodologies has complicated interpretation, comparison, and reproduction of important findings. To address this problem a comprehensive multicenter study was designed to develop guidelines that limit experimental and data reporting variability and provide a foundation for accurate comparison of data between studies. Common methodologies and data reporting protocols for tissue dissociation, cell yield, cell viability, FACS, and postsort purity were established. Seven centers tested the standardized methods by FACS-isolating a specific crypt-based epithelial population (EpCAM+/CD44+) from murine small intestine. Genetic biomarkers for stem/progenitor (Lgr5 and Atoh 1) and differentiated cell lineages (lysozyme, mucin2, chromogranin A, and sucrase isomaltase) were interrogated in target and control populations to assess intra- and intercenter variability. Wilcoxon's rank sum test on gene expression levels showed limited intracenter variability between biological replicates. Principal component analysis demonstrated significant intercenter reproducibility among four centers. Analysis of data collected by standardized cell isolation methods and data reporting requirements readily identified methodological problems, indicating that standard reporting parameters facilitate post hoc error identification. These results indicate that the complexity of FACS isolation of target intestinal epithelial populations can be highly reproducible between biological replicates and different institutions by adherence to common cell isolation methods and FACS gating strategies. This study can be considered a foundation for continued method development and a starting point for investigators that are developing cell isolation expertise to study physiology and

Magnetization of individual yeast cells by in situ formation of iron oxide on cell surfaces

Science.gov (United States)

Choi, Jinsu; Lee, Hojae; Choi, Insung S.; Yang, Sung Ho

2017-09-01

Magnetic functionalization of living cells has intensively been investigated with the aim of various bioapplications such as selective separation, targeting, and localization of the cells by using an external magnetic field. However, the magnetism has not been introduced to individual living cells through the in situ chemical reactions because of harsh conditions required for synthesis of magnetic materials. In this work, magnetic iron oxide was formed on the surface of living cells by optimizing reactions conditions to be mild sufficiently enough to sustain cell viability. Specifically, the reactive LbL strategy led to formation of magnetically responsive yeast cells with iron oxide shells. This facile and direct post-magnetization method would be a useful tool for remote manipulation of living cells with magnetic interactions, which is an important technique for the integration of cell-based circuits and the isolation of cell in microfluidic devices.

Chip-based droplet sorting

Energy Technology Data Exchange (ETDEWEB)

Beer, Neil Reginald; Lee, Abraham; Hatch, Andrew

2017-11-21

A non-contact system for sorting monodisperse water-in-oil emulsion droplets in a microfluidic device based on the droplet's contents and their interaction with an applied electromagnetic field or by identification and sorting.

Magnetic field exposure stiffens regenerating plant protoplast cell walls.

Science.gov (United States)

Haneda, Toshihiko; Fujimura, Yuu; Iino, Masaaki

2006-02-01

Single suspension-cultured plant cells (Catharanthus roseus) and their protoplasts were anchored to a glass plate and exposed to a magnetic field of 302 +/- 8 mT for several hours. Compression forces required to produce constant cell deformation were measured parallel to the magnetic field by means of a cantilever-type force sensor. Exposure of intact cells to the magnetic field did not result in any changes within experimental error, while exposure of regenerating protoplasts significantly increased the measured forces and stiffened regenerating protoplasts. The diameters of intact cells or regenerating protoplasts were not changed after exposure to the magnetic field. Measured forces for regenerating protoplasts with and without exposure to the magnetic field increased linearly with incubation time, with these forces being divided into components based on the elasticity of synthesized cell walls and cytoplasm. Cell wall synthesis was also measured using a cell wall-specific fluorescent dye, and no changes were noted after exposure to the magnetic field. Analysis suggested that exposure to the magnetic field roughly tripled the Young's modulus of the newly synthesized cell wall without any lag.

Sorting of cells of the same size, shape, and cell cycle stage for a single cell level assay without staining

Directory of Open Access Journals (Sweden)

Yomo Tetsuya

2006-06-01

Full Text Available Abstract Background Single-cell level studies are being used increasingly to measure cell properties not directly observable in a cell population. High-performance data acquisition systems for such studies have, by necessity, developed in synchrony. However, improvements in sample purification techniques are also required to reveal new phenomena. Here we assessed a cell sorter as a sample-pretreatment tool for a single-cell level assay. A cell sorter is routinely used for selecting one type of cells from a heterogeneous mixture of cells using specific fluorescence labels. In this case, we wanted to select cells of exactly the same size, shape, and cell-cycle stage from a population, without using a specific fluorescence label. Results We used four light scatter parameters: the peak height and area of the forward scatter (FSheight and FSarea and side scatter (SSheight and SSarea. The rat pheochromocytoma PC12 cell line, a neuronal cell line, was used for all experiments. The living cells concentrated in the high FSarea and middle SSheight/SSarea fractions. Single cells without cell clumps were concentrated in the low SS and middle FS fractions, and in the higher FSheight/FSarea and SSheight/SSarea fractions. The cell populations from these viable, single-cell-rich fractions were divided into twelve subfractions based on their FSarea-SSarea profiles, for more detailed analysis. We found that SSarea was proportional to the cell volume and the FSarea correlated with cell roundness and elongation, as well as with the level of DNA in the cell. To test the method and to characterize the basic properties of the isolated single cells, sorted cells were cultured in separate wells. The cells in all subfractions survived, proliferated and differentiated normally, suggesting that there was no serious damage. The smallest, roundest, and smoothest cells had the highest viability. There was no correlation between proliferation and differentiation. NGF increases

Disease-Causing Mutations in BEST1 Gene Are Associated with Altered Sorting of Bestrophin-1 Protein

Science.gov (United States)

Doumanov, Jordan A.; Zeitz, Christina; Gimenez, Paloma Dominguez; Audo, Isabelle; Krishna, Abhay; Alfano, Giovanna; Diaz, Maria Luz Bellido; Moskova-Doumanova, Veselina; Lancelot, Marie-Elise; Sahel, José-Alain; Nandrot, Emeline F.; Bhattacharya, Shomi S.

2013-01-01

Mutations in BEST1 gene, encoding the bestrophin-1 (Best1) protein are associated with macular dystrophies. Best1 is predominantly expressed in the retinal pigment epithelium (RPE), and is inserted in its basolateral membrane. We investigated the cellular localization in polarized MDCKII cells of disease-associated Best1 mutant proteins to study specific sorting motifs of Best1. Real-time PCR and western blots for endogenous expression of BEST1 in MDCK cells were performed. Best1 mutant constructs were generated using site-directed mutagenesis and transfected in MDCK cells. For protein sorting, confocal microscopy studies, biotinylation assays and statistical methods for quantification of mislocalization were used. Analysis of endogenous expression of BEST1 in MDCK cells revealed the presence of BEST1 transcript but no protein. Confocal microscopy and quantitative analyses indicate that transfected normal human Best1 displays a basolateral localization in MDCK cells, while cell sorting of several Best1 mutants (Y85H, Q96R, L100R, Y227N, Y227E) was altered. In contrast to constitutively active Y227E, constitutively inactive Y227F Best1 mutant localized basolaterally similar to the normal Best1 protein. Our data suggest that at least three basolateral sorting motifs might be implicated in proper Best1 basolateral localization. In addition, non-phosphorylated tyrosine 227 could play a role for basolateral delivery. PMID:23880862

Algorithm Sorts Groups Of Data

Science.gov (United States)

Evans, J. D.

1987-01-01

For efficient sorting, algorithm finds set containing minimum or maximum most significant data. Sets of data sorted as desired. Sorting process simplified by reduction of each multielement set of data to single representative number. First, each set of data expressed as polynomial with suitably chosen base, using elements of set as coefficients. Most significant element placed in term containing largest exponent. Base selected by examining range in value of data elements. Resulting series summed to yield single representative number. Numbers easily sorted, and each such number converted back to original set of data by successive division. Program written in BASIC.

Major proteins in normal human lymphocyte subpopulations separated by fluorescence-activated cell sorting and analyzed by two-dimensional gel electrophoresis

DEFF Research Database (Denmark)

Madsen, P S; Hokland, M; Ellegaard, J

1988-01-01

markers were observed in all cell types. All the putative protein markers have been identified in the protein database of human peripheral blood mononuclear cells (PBMCs) (see accompanying article by Celis et al.). Comparison of the overall patterns of protein synthesis of the unsorted PBMCs with those...... of the four subpopulations showed that the synthesis of some major PBMC proteins decreased substantially in the sorted subsets. These proteins are most likely not of monocyte origin, as these cells constituted only about 15% of the total PBMCs. Also, the inhibition does not seem to be due to the addition...

Non-chemotoxic induction of cancer cell death using magnetic nanowires

KAUST Repository

Contreras, Maria F.; Sougrat, Rachid; Zaher, Amir Omar; Ravasi, Timothy; Kosel, Jü rgen

2015-01-01

In this paper, we show that magnetic nanowires with weak magnetic fields and low frequencies can induce cell death via a mechanism that does not involve heat production. We incubated colon cancer cells with two concentrations (2.4 and 12 μg/mL) of nickel nanowires that were 35 nm in diameter and exposed the cells and nanowires to an alternating magnetic field (0.5 mT and 1 Hz or 1 kHz) for 10 or 30 minutes. This low-power field exerted a force on the magnetic nanowires, causing a mechanical disturbance to the cells. Transmission electron microscopy images showed that the nanostructures were internalized into the cells within 1 hour of incubation. Cell viability studies showed that the magnetic field and the nanowires separately had minor deleterious effects on the cells; however, when combined, the magnetic field and nanowires caused the cell viability values to drop by up to 39%, depending on the strength of the magnetic field and the concentration of the nanowires. Cell membrane leakage experiments indicated membrane leakage of 20%, suggesting that cell death mechanisms induced by the nanowires and magnetic field involve some cell membrane rupture. Results suggest that magnetic nanowires can kill cancer cells. The proposed process requires simple and low-cost equipment with exposure to only very weak magnetic fields for short time periods. © 2015 Contreras et al.

Non-chemotoxic induction of cancer cell death using magnetic nanowires

KAUST Repository

Contreras, Maria F.

2015-03-01

In this paper, we show that magnetic nanowires with weak magnetic fields and low frequencies can induce cell death via a mechanism that does not involve heat production. We incubated colon cancer cells with two concentrations (2.4 and 12 μg/mL) of nickel nanowires that were 35 nm in diameter and exposed the cells and nanowires to an alternating magnetic field (0.5 mT and 1 Hz or 1 kHz) for 10 or 30 minutes. This low-power field exerted a force on the magnetic nanowires, causing a mechanical disturbance to the cells. Transmission electron microscopy images showed that the nanostructures were internalized into the cells within 1 hour of incubation. Cell viability studies showed that the magnetic field and the nanowires separately had minor deleterious effects on the cells; however, when combined, the magnetic field and nanowires caused the cell viability values to drop by up to 39%, depending on the strength of the magnetic field and the concentration of the nanowires. Cell membrane leakage experiments indicated membrane leakage of 20%, suggesting that cell death mechanisms induced by the nanowires and magnetic field involve some cell membrane rupture. Results suggest that magnetic nanowires can kill cancer cells. The proposed process requires simple and low-cost equipment with exposure to only very weak magnetic fields for short time periods. © 2015 Contreras et al.

Micro-magnet arrays for specific single bacterial cell positioning

Energy Technology Data Exchange (ETDEWEB)

Pivetal, Jérémy, E-mail: jeremy.piv@netcmail.com [Ecole Centrale de Lyon, CNRS UMR 5005, Laboratoire Ampère, F-69134 Écully (France); Royet, David [Ecole Centrale de Lyon, CNRS UMR 5005, Laboratoire Ampère, F-69134 Écully (France); Ciuta, Georgeta [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Frenea-Robin, Marie [Université de Lyon, Université Lyon 1, CNRS UMR 5005, Laboratoire Ampère, F-69622 Villeurbanne (France); Haddour, Naoufel [Ecole Centrale de Lyon, CNRS UMR 5005, Laboratoire Ampère, F-69134 Écully (France); Dempsey, Nora M. [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Dumas-Bouchiat, Frédéric [Univ Limoges, CNRS, SPCTS UMR 7513, 12 Rue Atlantis, F-87068 Limoges (France); Simonet, Pascal [Ecole Centrale de Lyon, CNRS UMR 5005, Laboratoire Ampère, F-69134 Écully (France)

2015-04-15

In various contexts such as pathogen detection or analysis of microbial diversity where cellular heterogeneity must be taken into account, there is a growing need for tools and methods that enable microbiologists to analyze bacterial cells individually. One of the main challenges in the development of new platforms for single cell studies is to perform precise cell positioning, but the ability to specifically target cells is also important in many applications. In this work, we report the development of new strategies to selectively trap single bacterial cells upon large arrays, based on the use of micro-magnets. Escherichia coli bacteria were used to demonstrate magnetically driven bacterial cell organization. In order to provide a flexible approach adaptable to several applications in the field of microbiology, cells were magnetically and specifically labeled using two different strategies, namely immunomagnetic labeling and magnetic in situ hybridization. Results show that centimeter-sized arrays of targeted, isolated bacteria can be successfully created upon the surface of a flat magnetically patterned hard magnetic film. Efforts are now being directed towards the integration of a detection tool to provide a complete micro-system device for a variety of microbiological applications. - Highlights: 1.We report a new approach to selectively micropattern bacterial cells individually upon micro-magnet arrays. 2.Permanent micro-magnets of a size approaching that of bacteria could be fabricated using a Thermo-Magnetic Patterning process. 3.Bacterial cells were labeled using two different magnetic labeling strategies providing flexible approach adaptable to several applications in the field of microbiology.

Trapping, focusing, and sorting of microparticles through bubble streaming

Science.gov (United States)

Wang, Cheng; Jalikop, Shreyas; Hilgenfeldt, Sascha

2010-11-01

Ultrasound-driven oscillating microbubbles can set up vigorous steady streaming flows around the bubbles. In contrast to previous work, we make use of the interaction between the bubble streaming and the streaming induced around mobile particles close to the bubble. Our experiment superimposes a unidirectional Poiseuille flow containing a well-mixed suspension of neutrally buoyant particles with the bubble streaming. The particle-size dependence of the particle-bubble interaction selects which particles are transported and which particles are trapped near the bubbles. The sizes selected for can be far smaller than any scale imposed by the device geometry, and the selection mechanism is purely passive. Changing the amplitude and frequency of ultrasound driving, we can further control focusing and sorting of the trapped particles, leading to the emergence of sharply defined monodisperse particle streams within a much wider channel. Optimizing parameters for focusing and sorting are presented. The technique is applicable in important fields like cell sorting and drug delivery.

ScanSort{sup SM} at Whiteshell Laboratories for sorting of experimental cesium pond soil

Energy Technology Data Exchange (ETDEWEB)

Downey, H., E-mail: heath.downey@amecfw.com [Amec Foster Wheeler, Portland, ME (United States)

2015-07-01

The ScanSort{sup SM} soil sorting system is a unique and efficient radiological instrument used for measuring and sorting bulk soils and volumetric materials. The system performs automatic radioassay and segregation of preconditioned material using a gamma spectroscopy system mounted above a conveyor belt. It was deployed to the Whiteshell Laboratories site to process the excavated soils generated during the decommissioning of the former Experimental Cesium Pond. The ScanSort{sup SM} system was utilized to segregate material with Cs-137 concentrations above the established site unrestricted release and restricted site reuse levels as well as demonstrated the ability to accurately determine the radioactivity concentrations of the radiologically-impacted material and to confidently segregate volumes of that material for appropriate final disposition. (author)

Measurements of magnetic anisotropy in sickle cells

International Nuclear Information System (INIS)

Salvo Souza, L.H. de.

1982-03-01

Room temperature magnetic measurements in deoxigenated sickle cells showed the existence of magnetic anisotropy, Δchi=1,29 x 10 -3 . This effect was supposed paramagnetic and considered to be due to the iron atoms of the hemoglobin molecules which are one over the other, forming ordered chains inside the erythrocytes. Low temperature (liquid He - 4,2K) measurements of the magnetic anisotropy of sickle cells and normal red blood cells diluted in a cryoprotector was made to confirm the paramagnetic origin of the fenomena. For that purpose it was used a superconductor magnetometer coupled to a SQUID, developed in the 'Laboratorio do Estado Solido do Departamento de Fisica da PUC-RJ'. The results obtained seem to confirm the expected paramagnetic anisotropy and, furthermore, suggest the presence of magnetic interactions among the iron atoms in the sickle cells samples. (Author) [pt

PhySortR: a fast, flexible tool for sorting phylogenetic trees in R.

Science.gov (United States)

Stephens, Timothy G; Bhattacharya, Debashish; Ragan, Mark A; Chan, Cheong Xin

2016-01-01

A frequent bottleneck in interpreting phylogenomic output is the need to screen often thousands of trees for features of interest, particularly robust clades of specific taxa, as evidence of monophyletic relationship and/or reticulated evolution. Here we present PhySortR, a fast, flexible R package for classifying phylogenetic trees. Unlike existing utilities, PhySortR allows for identification of both exclusive and non-exclusive clades uniting the target taxa based on tip labels (i.e., leaves) on a tree, with customisable options to assess clades within the context of the whole tree. Using simulated and empirical datasets, we demonstrate the potential and scalability of PhySortR in analysis of thousands of phylogenetic trees without a priori assumption of tree-rooting, and in yielding readily interpretable trees that unambiguously satisfy the query. PhySortR is a command-line tool that is freely available and easily automatable.

Sorting out Downside Beta

NARCIS (Netherlands)

G.T. Post (Thierry); P. van Vliet (Pim); S.D. Lansdorp (Simon)

2009-01-01

textabstractDownside risk, when properly defined and estimated, helps to explain the cross-section of US stock returns. Sorting stocks by a proper estimate of downside market beta leads to a substantially larger cross-sectional spread in average returns than sorting on regular market beta. This

A planar conducting micro-loop structure for transportation of magnetic beads: An approach towards rapid sensing and quantification of biological entities

KAUST Repository

Gooneratne, Chinthaka Pasan; Giouroudi, Ioanna; Kosel, Jü rgen

2012-01-01

tools for accurate and rapid cell sorting and counting. Effective manipulation of beads is a critical factor for the performance of LOC devices. In this paper we propose a planar conducting micro-loop structure to trap, manipulate and transport magnetic

Design of a novel magnetic platform for cell manipulation

Science.gov (United States)

Lucarini, Gioia; Iacovacci, Veronica; Gouveia, Pedro J.; Ricotti, Leonardo; Menciassi, Arianna

2018-02-01

Cell manipulation tasks, especially in lab-on-a-chip applications for personalized medicine, could greatly benefit from mobile untethered microdevices able to wirelessly navigate in fluidic environments by means of magnetic fields. In this paper, the design, fabrication and testing of a magnetic platform enabling the controlled locomotion and immersion of microrobots placed at the air/liquid interface is proposed and exploited for cell manipulation. The proposed microrobot consists of a polymeric magnetic thin film that acts as cell transporter and a specific coating strategy, devised to enhance a safe cancer cell adhesion to the magnetic film. Experimental results demonstrated an overall cell viability and a fine control of magnetic microrobot locomotion. The proposed technologies are promising in view of future cell manipulation tasks for personalized medicine applications.

Three Sorts of Naturalism

DEFF Research Database (Denmark)

Fink, Hans

2006-01-01

In "Two sorts of Naturalism" John McDowell is sketching his own sort of naturalism in ethics as an alternative to "bald naturalism". In this paper I distinguish materialist, idealist and absolute conceptions of nature and of naturalism in order to provide a framework for a clearer understanding...

Non-chemotoxic induction of cancer cell death using magnetic nanowires

Directory of Open Access Journals (Sweden)

Contreras MF

2015-03-01

Full Text Available Maria F Contreras,1 Rachid Sougrat,2 Amir Zaher,3 Timothy Ravasi,1,3 Jürgen Kosel3 1Division of Biological and Environmental Sciences and Engineering, 2Advanced Nanofabrication Imaging and Characterization, 3Division of Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia Abstract: In this paper, we show that magnetic nanowires with weak magnetic fields and low frequencies can induce cell death via a mechanism that does not involve heat production. We incubated colon cancer cells with two concentrations (2.4 and 12 µg/mL of nickel nanowires that were 35 nm in diameter and exposed the cells and nanowires to an alternating magnetic field (0.5 mT and 1 Hz or 1 kHz for 10 or 30 minutes. This low-power field exerted a force on the magnetic nanowires, causing a mechanical disturbance to the cells. Transmission electron microscopy images showed that the nanostructures were internalized into the cells within 1 hour of incubation. Cell viability studies showed that the magnetic field and the nanowires separately had minor deleterious effects on the cells; however, when combined, the magnetic field and nanowires caused the cell viability values to drop by up to 39%, depending on the strength of the magnetic field and the concentration of the nanowires. Cell membrane leakage experiments indicated membrane leakage of 20%, suggesting that cell death mechanisms induced by the nanowires and magnetic field involve some cell membrane rupture. Results suggest that magnetic nanowires can kill cancer cells. The proposed process requires simple and low-cost equipment with exposure to only very weak magnetic fields for short time periods. Keywords: cell death induction, low frequency alternating magnetic field, nanomedicine, nanowire internalization, nickel nanowires

Enhancement of Selection, Bubble and Insertion Sorting Algorithm

OpenAIRE

Muhammad Farooq Umar; Ehsan Ullah Munir; Shafqat Ali Shad; Muhammad Wasif Nisar

2014-01-01

In everyday life there is a large amount of data to arrange because sorting removes any ambiguities and make the data analysis and data processing very easy, efficient and provides with cost less effort. In this study a set of improved sorting algorithms are proposed which gives better performance and design idea. In this study five new sorting algorithms (Bi-directional Selection Sort, Bi-directional bubble sort, MIDBiDirectional Selection Sort, MIDBidirectional bubble sort and linear insert...

Sorting waves and associated eigenvalues

Science.gov (United States)

Carbonari, Costanza; Colombini, Marco; Solari, Luca

2017-04-01

The presence of mixed sediment always characterizes gravel bed rivers. Sorting processes take place during bed load transport of heterogeneous sediment mixtures. The two main elements necessary to the occurrence of sorting are the heterogeneous character of sediments and the presence of an active sediment transport. When these two key ingredients are simultaneously present, the segregation of bed material is consistently detected both in the field [7] and in laboratory [3] observations. In heterogeneous sediment transport, bed altimetric variations and sorting always coexist and both mechanisms are independently capable of driving the formation of morphological patterns. Indeed, consistent patterns of longitudinal and transverse sorting are identified almost ubiquitously. In some cases, such as bar formation [2] and channel bends [5], sorting acts as a stabilizing effect and therefore the dominant mechanism driving pattern formation is associated with bed altimetric variations. In other cases, such as longitudinal streaks, sorting enhances system instability and can therefore be considered the prevailing mechanism. Bedload sheets, first observed by Khunle and Southard [1], represent another classic example of a morphological pattern essentially triggered by sorting, as theoretical [4] and experimental [3] results suggested. These sorting waves cause strong spatial and temporal fluctuations of bedload transport rate typical observed in gravel bed rivers. The problem of bed load transport of a sediment mixture is formulated in the framework of a 1D linear stability analysis. The base state consists of a uniform flow in an infinitely wide channel with active bed load transport. The behaviour of the eigenvalues associated with fluid motion, bed evolution and sorting processes in the space of the significant flow and sediment parameters is analysed. A comparison is attempted with the results of the theoretical analysis of Seminara Colombini and Parker [4] and Stecca

Diffusion in a tokamak with helical magnetic cells

International Nuclear Information System (INIS)

Wakatani, Masahiro

1975-05-01

In a tokamak with helical magnetic cells produced by a resonant helical magnetic field, diffusion in the collisional regime is studied. The diffusion coefficient is greatly enhanced near the resonant surface even for a weak helical magnetic field. A theoretical model for disruptive instabilities based on the enhanced transport due to helical magnetic cells is discussed. This may explain experiments of the tokamak with resonant helical fields qualitatively. (author)

Bio optofluidics cell sorter: cell-BOCS concept and applications

Science.gov (United States)

Roth, Tue; Glückstad, Jesper

2012-03-01

The cell-BOCS is a novel microfluidics based cell-sorting instrument utilizing next generation optical trapping technology developed at the Technical University of Denmark. It is targeted emerging bio-medical research and diagnostics markets where it for certain applications offers a number of advantages over conventional fluorescence activated cell-sorting (FACSTM) technology. Advantages include gentle handling of cells, sterile sorting, easy operation, small footprint and lower cost allowing out-of-core-facility use. Application examples are found within sorting of fragile transfected cells, high value samples and primary cell lines, where traditional FACS technology has limited application due to it's droplet-based approach to cell-sorting. In the diagnostics field, in particular applying the cell-BOCS for isolating pure populations of circulating tumor cells is an area that has generated a lot of interest.

Application of magnetic carriers to two examples of quantitative cell analysis

Energy Technology Data Exchange (ETDEWEB)

Zhou, Chen; Qian, Zhixi; Choi, Young Suk; David, Allan E. [Department of Chemical Engineering, 212 Ross Hall, Auburn University, Auburn, AL 36849 (United States); Todd, Paul, E-mail: pwtodd@hotmail.com [Techshot, Inc., 7200 Highway 150, Greenville, IN 47124 (United States); Hanley, Thomas R. [Department of Chemical Engineering, 212 Ross Hall, Auburn University, Auburn, AL 36849 (United States)

2017-04-01

The use of magnetophoretic mobility as a surrogate for fluorescence intensity in quantitative cell analysis was investigated. The objectives of quantitative fluorescence flow cytometry include establishing a level of labeling for the setting of parameters in fluorescence activated cell sorters (FACS) and the determination of levels of uptake of fluorescently labeled substrates by living cells. Likewise, the objectives of quantitative magnetic cytometry include establishing a level of labeling for the setting of parameters in flowing magnetic cell sorters and the determination of levels of uptake of magnetically labeled substrates by living cells. The magnetic counterpart to fluorescence intensity is magnetophoretic mobility, defined as the velocity imparted to a suspended cell per unit of magnetic ponderomotive force. A commercial velocimeter available for making this measurement was used to demonstrate both applications. Cultured Gallus lymphoma cells were immunolabeled with commercial magnetic beads and shown to have adequate magnetophoretic mobility to be separated by a novel flowing magnetic separator. Phagocytosis of starch nanoparticles having magnetic cores by cultured Chinese hamster ovary cells, a CHO line, was quantified on the basis of magnetophoretic mobility. - Highlights: • Commercial particle tracking velocimetry measures magnetophoretic mobility of labeled cells. • Magnetically labeled tumor cells were shown to have adequate mobility for capture in a specific sorter. • The kinetics of nonspecific endocytosis of magnetic nanomaterials by CHO cells was characterized. • Magnetic labeling of cells can be used like fluorescence flow cytometry for quantitative cell analysis.

The assessment of CD146-based cell sorting and telomere length analysis for establishing the identity of mesenchymal stem cells in human umbilical cord [v2; ref status: indexed, http://f1000r.es/48d

Directory of Open Access Journals (Sweden)

Dimitrios Kouroupis

2014-08-01

Full Text Available Adult stem cells are characterised by longer telomeres compared to mature cells from the same tissue. In this study, candidate CD146+ umbilical cord (UC mesenchymal stem cells (MSCs were purified by cell sorting from UC tissue digests and their telomere lengths were measured in comparison to donor-matched CD146-negative fraction.   UC tissue fragments were enzymatically treated with collagenase and the cells were used for cell sorting, colony-forming fibroblast (CFU-F assay or for long-term MSC cultivation. Telomere lengths were measured by qPCR in both culture-expanded MSCs and candidate native UC MSCs. Immunohistochemistry was undertaken to study the topography of CD146+ cells.   Culture-expanded UC MSCs had a stable expression of CD73, CD90 and CD105, whereas CD146 declined in later passages which correlated with the shortening of telomeres in the same cultures. In five out of seven donors, telomeres in candidate native UC MSCs (CD45-CD235α-CD31-CD146+ were longer compared to donor-matched CD146- population (CD45-CD235α-CD31-CD146-. The frequency of CD45-CD235α-CD31-CD146+ cells measured by flow cytometry was ~1000-fold above that of CFU-Fs (means 10.4% and 0.01%, respectively. CD146+ cells were also abundant in situ having a broad topography including high levels of positivity in muscle areas in addition to vessels.   Although qPCR-based telomere length analysis in sorted populations could be limited in its sensitivity, very high frequency of CD146+ cells in UC tissue suggests that CD146 expression alone is unlikely to be sufficient to identify and purify native MSCs from the UC tissue.

Single cell detection using a magnetic zigzag nanowire biosensor.

Science.gov (United States)

Huang, Hao-Ting; Ger, Tzong-Rong; Lin, Ya-Hui; Wei, Zung-Hang

2013-08-07

A magnetic zigzag nanowire device was designed for single cell biosensing. Nanowires with widths of 150, 300, 500, and 800 nm were fabricated on silicon trenches by electron beam lithography, electron beam evaporation, and lift-off processes. Magnetoresistance measurements were performed before and after the attachment of a single magnetic cell to the nanowires to characterize the magnetic signal change due to the influence of the magnetic cell. Magnetoresistance responses were measured in different magnetic field directions, and the results showed that this nanowire device can be used for multi-directional detection. It was observed that the highest switching field variation occurred in a 150 nm wide nanowire when the field was perpendicular to the substrate plane. On the other hand, the highest magnetoresistance ratio variation occurred in a 800 nm wide nanowire also when the field was perpendicular to the substrate plane. Besides, the trench-structured substrate proposed in this study can fix the magnetic cell to the sensor in a fluid environment, and the stray field generated by the corners of the magnetic zigzag nanowires has the function of actively attracting the magnetic cells for detection.

Cache-Aware and Cache-Oblivious Adaptive Sorting

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Fagerberg, Rolf; Moruz, Gabriel

2005-01-01

Two new adaptive sorting algorithms are introduced which perform an optimal number of comparisons with respect to the number of inversions in the input. The first algorithm is based on a new linear time reduction to (non-adaptive) sorting. The second algorithm is based on a new division protocol...... for the GenericSort algorithm by Estivill-Castro and Wood. From both algorithms we derive I/O-optimal cache-aware and cache-oblivious adaptive sorting algorithms. These are the first I/O-optimal adaptive sorting algorithms....

Prions amplify through degradation of the VPS10P sorting receptor sortilin.

Science.gov (United States)

Uchiyama, Keiji; Tomita, Mitsuru; Yano, Masashi; Chida, Junji; Hara, Hideyuki; Das, Nandita Rani; Nykjaer, Anders; Sakaguchi, Suehiro

2017-06-01

Prion diseases are a group of fatal neurodegenerative disorders caused by prions, which consist mainly of the abnormally folded isoform of prion protein, PrPSc. A pivotal pathogenic event in prion disease is progressive accumulation of prions, or PrPSc, in brains through constitutive conformational conversion of the cellular prion protein, PrPC, into PrPSc. However, the cellular mechanism by which PrPSc is progressively accumulated in prion-infected neurons remains unknown. Here, we show that PrPSc is progressively accumulated in prion-infected cells through degradation of the VPS10P sorting receptor sortilin. We first show that sortilin interacts with PrPC and PrPSc and sorts them to lysosomes for degradation. Consistently, sortilin-knockdown increased PrPSc accumulation in prion-infected cells. In contrast, overexpression of sortilin reduced PrPSc accumulation in prion-infected cells. These results indicate that sortilin negatively regulates PrPSc accumulation in prion-infected cells. The negative role of sortilin in PrPSc accumulation was further confirmed in sortilin-knockout mice infected with prions. The infected mice had accelerated prion disease with early accumulation of PrPSc in their brains. Interestingly, sortilin was reduced in prion-infected cells and mouse brains. Treatment of prion-infected cells with lysosomal inhibitors, but not proteasomal inhibitors, increased the levels of sortilin. Moreover, sortilin was reduced following PrPSc becoming detectable in cells after infection with prions. These results indicate that PrPSc accumulation stimulates sortilin degradation in lysosomes. Taken together, these results show that PrPSc accumulation of itself could impair the sortilin-mediated sorting of PrPC and PrPSc to lysosomes for degradation by stimulating lysosomal degradation of sortilin, eventually leading to progressive accumulation of PrPSc in prion-infected cells.

An Unsupervised Online Spike-Sorting Framework.

Science.gov (United States)

Knieling, Simeon; Sridharan, Kousik S; Belardinelli, Paolo; Naros, Georgios; Weiss, Daniel; Mormann, Florian; Gharabaghi, Alireza

2016-08-01

Extracellular neuronal microelectrode recordings can include action potentials from multiple neurons. To separate spikes from different neurons, they can be sorted according to their shape, a procedure referred to as spike-sorting. Several algorithms have been reported to solve this task. However, when clustering outcomes are unsatisfactory, most of them are difficult to adjust to achieve the desired results. We present an online spike-sorting framework that uses feature normalization and weighting to maximize the distinctiveness between different spike shapes. Furthermore, multiple criteria are applied to either facilitate or prevent cluster fusion, thereby enabling experimenters to fine-tune the sorting process. We compare our method to established unsupervised offline (Wave_Clus (WC)) and online (OSort (OS)) algorithms by examining their performance in sorting various test datasets using two different scoring systems (AMI and the Adamos metric). Furthermore, we evaluate sorting capabilities on intra-operative recordings using established quality metrics. Compared to WC and OS, our algorithm achieved comparable or higher scores on average and produced more convincing sorting results for intra-operative datasets. Thus, the presented framework is suitable for both online and offline analysis and could substantially improve the quality of microelectrode-based data evaluation for research and clinical application.

Data Sorting Using Graphics Processing Units

Directory of Open Access Journals (Sweden)

M. J. Mišić

2012-06-01

Full Text Available Graphics processing units (GPUs have been increasingly used for general-purpose computation in recent years. The GPU accelerated applications are found in both scientific and commercial domains. Sorting is considered as one of the very important operations in many applications, so its efficient implementation is essential for the overall application performance. This paper represents an effort to analyze and evaluate the implementations of the representative sorting algorithms on the graphics processing units. Three sorting algorithms (Quicksort, Merge sort, and Radix sort were evaluated on the Compute Unified Device Architecture (CUDA platform that is used to execute applications on NVIDIA graphics processing units. Algorithms were tested and evaluated using an automated test environment with input datasets of different characteristics. Finally, the results of this analysis are briefly discussed.

Big Five Measurement via Q-Sort

Directory of Open Access Journals (Sweden)

Chris D. Fluckinger

2014-08-01

Full Text Available Socially desirable responding presents a difficult challenge in measuring personality. I tested whether a partially ipsative measure—a normatively scored Q-sort containing traditional Big Five items—would produce personality scores indicative of less socially desirable responding compared with Likert-based measures. Across both instructions to respond honestly and in the context of applying for a job, the Q-sort produced lower mean scores, lower intercorrelations between dimensions, and similar validity in predicting supervisor performance ratings to Likert. In addition, the Q-sort produced a more orthogonal structure (but not fully orthogonal when modeled at the latent level. These results indicate that the Q-sort method did constrain socially desirable responding. Researchers and practitioners should consider Big Five measurement via Q-sort for contexts in which high socially desirable responding is expected.

Online sorting of recovered wood waste by automated XRF-technology: part II. Sorting efficiencies.

Science.gov (United States)

Hasan, A Rasem; Solo-Gabriele, Helena; Townsend, Timothy

2011-04-01

Sorting of waste wood is an important process practiced at recycling facilities in order to detect and divert contaminants from recycled wood products. Contaminants of concern include arsenic, chromium and copper found in chemically preserved wood. The objective of this research was to evaluate the sorting efficiencies of both treated and untreated parts of the wood waste stream, and metal (As, Cr and Cu) mass recoveries by the use of automated X-ray fluorescence (XRF) systems. A full-scale system was used for experimentation. This unit consisted of an XRF-detection chamber mounted on the top of a conveyor and a pneumatic slide-way diverter which sorted wood into presumed treated and presumed untreated piles. A randomized block design was used to evaluate the operational conveyance parameters of the system, including wood feed rate and conveyor belt speed. Results indicated that online sorting efficiencies of waste wood by XRF technology were high based on number and weight of pieces (70-87% and 75-92% for treated wood and 66-97% and 68-96% for untreated wood, respectively). These sorting efficiencies achieved mass recovery for metals of 81-99% for As, 75-95% for Cu and 82-99% of Cr. The incorrect sorting of wood was attributed almost equally to deficiencies in the detection and conveyance/diversion systems. Even with its deficiencies, the system was capable of producing a recyclable portion that met residential soil quality levels established for Florida, for an infeed that contained 5% of treated wood. Copyright © 2010 Elsevier Ltd. All rights reserved.

Pengembangan Algoritma Pengurutan SMS (Scan, Move, And Sort)

OpenAIRE

Lubis, Denni Aprilsyah

2015-01-01

Sorting has been a profound area for the algorithmic researchers. And many resources are invested to suggest a more working sorting algorithm. For this purpose many existing sorting algorithms were observed in terms of the efficiency of the algorithmic complexity. Efficient sorting is important to optimize the use of other algorithms that require sorted lists to work correctly. sorting has been considered as a fundamental problem in the study of algorithms that due to many reas...

Word Sorts for General Music Classes

Science.gov (United States)

Cardany, Audrey Berger

2015-01-01

Word sorts are standard practice for aiding children in acquiring skills in English language arts. When included in the general music classroom, word sorts may aid students in acquiring a working knowledge of music vocabulary. The author shares a word sort activity drawn from vocabulary in John Lithgow's children's book "Never Play…

A Sequence of Sorting Strategies.

Science.gov (United States)

Duncan, David R.; Litwiller, Bonnie H.

1984-01-01

Describes eight increasingly sophisticated and efficient sorting algorithms including linear insertion, binary insertion, shellsort, bubble exchange, shakersort, quick sort, straight selection, and tree selection. Provides challenges for the reader and the student to program these efficiently. (JM)

Magnetic stem cell targeting to the inner ear

Science.gov (United States)

Le, T. N.; Straatman, L.; Yanai, A.; Rahmanian, R.; Garnis, C.; Häfeli, U. O.; Poblete, T.; Westerberg, B. D.; Gregory-Evans, K.

2017-12-01

Severe sensorineural deafness is often accompanied by a loss of auditory neurons in addition to injury of the cochlear epithelium and hair cell loss. Cochlear implant function however depends on a healthy complement of neurons and their preservation is vital in achieving optimal results. We have developed a technique to target mesenchymal stem cells (MSCs) to a deafened rat cochlea. We then assessed the neuroprotective effect of systematically delivered MSCs on the survival and function of spiral ganglion neurons (SGNs). MSCs were labeled with superparamagnetic nanoparticles, injected via the systemic circulation, and targeted using a magnetized cochlea implant and external magnet. Neurotrophic factor concentrations, survival of SGNs, and auditory function were assessed at 1 week and 4 weeks after treatments and compared against multiple control groups. Significant numbers of magnetically targeted MSCs (>30 MSCs/section) were present in the cochlea with accompanied elevation of brain-derived neurotrophic factor and glial cell-derived neurotrophic factor levels (p < 0.001). In addition we saw improved survival of SGNs (approximately 80% survival at 4 weeks). Hearing threshold levels in magnetically targeted rats were found to be significantly better than those of control rats (p < 0.05). These results indicate that magnetic targeting of MSCs to the cochlea can be accomplished with a magnetized cochlear permalloy implant and an external magnet. The targeted stem cells release neurotrophic factors which results in improved SGN survival and hearing recovery. Combining magnetic cell-based therapy and cochlear implantation may improve cochlear implant function in treating deafness.

Fixing the Sorting Algorithm for Android, Java and Python

NARCIS (Netherlands)

C.P.T. de Gouw (Stijn); F.S. de Boer (Frank)

2015-01-01

htmlabstractTim Peters developed the Timsort hybrid sorting algorithm in 2002. TimSort was first developed for Python, a popular programming language, but later ported to Java (where it appears as java.util.Collections.sort and java.util.Arrays.sort). TimSort is today used as the default sorting

IMPLEMENTATION OF SERIAL AND PARALLEL BUBBLE SORT ON FPGA

Directory of Open Access Journals (Sweden)

Dwi Marhaendro Jati Purnomo

2016-06-01

Full Text Available Sorting is common process in computational world. Its utilization are on many fields from research to industry. There are many sorting algorithm in nowadays. One of the simplest yet powerful is bubble sort. In this study, bubble sort is implemented on FPGA. The implementation was taken on serial and parallel approach. Serial and parallel bubble sort then compared by means of its memory, execution time, and utility which comprises slices and LUTs. The experiments show that serial bubble sort required smaller memory as well as utility compared to parallel bubble sort. Meanwhile, parallel bubble sort performed faster than serial bubble sort

Automatic spike sorting using tuning information.

Science.gov (United States)

Ventura, Valérie

2009-09-01

Current spike sorting methods focus on clustering neurons' characteristic spike waveforms. The resulting spike-sorted data are typically used to estimate how covariates of interest modulate the firing rates of neurons. However, when these covariates do modulate the firing rates, they provide information about spikes' identities, which thus far have been ignored for the purpose of spike sorting. This letter describes a novel approach to spike sorting, which incorporates both waveform information and tuning information obtained from the modulation of firing rates. Because it efficiently uses all the available information, this spike sorter yields lower spike misclassification rates than traditional automatic spike sorters. This theoretical result is verified empirically on several examples. The proposed method does not require additional assumptions; only its implementation is different. It essentially consists of performing spike sorting and tuning estimation simultaneously rather than sequentially, as is currently done. We used an expectation-maximization maximum likelihood algorithm to implement the new spike sorter. We present the general form of this algorithm and provide a detailed implementable version under the assumptions that neurons are independent and spike according to Poisson processes. Finally, we uncover a systematic flaw of spike sorting based on waveform information only.

Magnetic cell labeling of primary and stem cell-derived pig hepatocytes for MRI-based cell tracking of hepatocyte transplantation.

Directory of Open Access Journals (Sweden)

Dwayne R Roach

Full Text Available Pig hepatocytes are an important investigational tool for optimizing hepatocyte transplantation schemes in both allogeneic and xenogeneic transplant scenarios. MRI can be used to serially monitor the transplanted cells, but only if the hepatocytes can be labeled with a magnetic particle. In this work, we describe culture conditions for magnetic cell labeling of cells from two different pig hepatocyte cell sources; primary pig hepatocytes (ppHEP and stem cell-derived hepatocytes (PICM-19FF. The magnetic particle is a micron-sized iron oxide particle (MPIO that has been extensively studied for magnetic cell labeling for MRI-based cell tracking. ppHEP could endocytose MPIO with labeling percentages as high as 70%, achieving iron content as high as ~55 pg/cell, with >75% viability. PICM-19FF had labeling >97%, achieving iron content ~38 pg/cell, with viability >99%. Extensive morphological and functional assays indicated that magnetic cell labeling was benign to the cells. The results encourage the use of MRI-based cell tracking for the development and clinical use of hepatocyte transplantation methodologies. Further, these results generally highlight the importance of functional cell assays in the evaluation of contrast agent biocompatibility.

A Preliminary Study of MSD-First Radix-Sorting Methed

OpenAIRE

小田, 哲久

1984-01-01

Many kinds of sorting algorithms have been developed from the age of Punched Card System. Nowadays, any sorting algorithm can be called either (1) internal sorting methed or (2) external sorting method. Internal sorting method is used only when the number of records to be sorted (N) is not so large for the internal memory of the computer system. Larger memory space has become available with the aid of semiconductor technology. Therefore, it might be desired to develop a new internal sorting m...

Data parallel sorting for particle simulation

Science.gov (United States)

Dagum, Leonardo

1992-01-01

Sorting on a parallel architecture is a communications intensive event which can incur a high penalty in applications where it is required. In the case of particle simulation, only integer sorting is necessary, and sequential implementations easily attain the minimum performance bound of O (N) for N particles. Parallel implementations, however, have to cope with the parallel sorting problem which, in addition to incurring a heavy communications cost, can make the minimun performance bound difficult to attain. This paper demonstrates how the sorting problem in a particle simulation can be reduced to a merging problem, and describes an efficient data parallel algorithm to solve this merging problem in a particle simulation. The new algorithm is shown to be optimal under conditions usual for particle simulation, and its fieldwise implementation on the Connection Machine is analyzed in detail. The new algorithm is about four times faster than a fieldwise implementation of radix sort on the Connection Machine.

Stochastic Model of Vesicular Sorting in Cellular Organelles

Science.gov (United States)

Vagne, Quentin; Sens, Pierre

2018-02-01

The proper sorting of membrane components by regulated exchange between cellular organelles is crucial to intracellular organization. This process relies on the budding and fusion of transport vesicles, and should be strongly influenced by stochastic fluctuations, considering the relatively small size of many organelles. We identify the perfect sorting of two membrane components initially mixed in a single compartment as a first passage process, and we show that the mean sorting time exhibits two distinct regimes as a function of the ratio of vesicle fusion to budding rates. Low ratio values lead to fast sorting but result in a broad size distribution of sorted compartments dominated by small entities. High ratio values result in two well-defined sorted compartments but sorting is exponentially slow. Our results suggest an optimal balance between vesicle budding and fusion for the rapid and efficient sorting of membrane components and highlight the importance of stochastic effects for the steady-state organization of intracellular compartments.

Application of visible spectroscopy in waste sorting

Science.gov (United States)

Spiga, Philippe; Bourely, Antoine

2011-10-01

Today, waste recycling, (bottles, papers...), is a mechanical operation: the waste are crushed, fused and agglomerated in order to obtain new manufactured products (e.g. new bottles, clothes ...). The plastics recycling is the main application in the color sorting process. The colorless plastics recovered are more valuable than the colored plastics. Other emergent applications are in the paper sorting, where the main goal is to sort dyed paper from white papers. Up to now, Pellenc Selective Technologies has manufactured color sorting machines based on RGB cameras. Three dimensions (red, green and blue) are no longer sufficient to detect low quantities of dye in the considered waste. In order to increase the efficiency of the color detection, a new sorting machine, based on visible spectroscopy, has been developed. This paper presents the principles of the two approaches and their difference in terms of sorting performance, making visible spectroscopy a clear winner.

[Autologous regulatory T cells can suppress the proliferation of lymphoma cell line in vitro].

Science.gov (United States)

Ying, Zhi-Tao; Guo, Jun; Ren, Jun; Kong, Yan; Yuan, Zhi-Hong; Liu, Xi-Juan; Zhang, Chen; Zheng, Wen; Song, Yu-Qin; Zhang, Yun-Tao; Zhu, Jun

2009-06-01

This study was aimed to investigate the suppressive effect of regulatory T (Treg) cells on the T cell lymphoma EL4 cell line and to explore its mechanism. C57BL/6 Mouse Treg cells were isolated by MACS (magnetic cell sorting). The purity and the expression of Foxp3 were detected by flow cytometry. The suppressive effect of sorted Treg cells on EL4 cells was detected by MTT assay. The secretion of TGF-beta1 and IL-10 was examined by enzyme-linked immunosorbent assay (ELISA). The results showed that CD4(+)CD25(+) T cells could be successfully isolated by MACS with the purity reaching 91.6% and the expression level of Foxp3 was 78.9%. The ratio of viable cells was more than 95%. Regulatory T cells could suppress the proliferation of EL4 cells effectively in the presence of antigen presenting cells (APCs). And the suppressive effect was most significant at 1:1 ratio. In addition, the suppression still existed without APCs. TGF-beta1 and IL-10 could not be detected by ELISA. It is concluded that the Treg cells can suppress T lymphoma cell in vitro. The suppressive effect of Treg cells works in dose-dependent manner, but not in cytokine-dependent manner. The mechanism of this suppression may take effect through cell-cell contact.

High purity microfluidic sorting and analysis of circulating tumor cells: towards routine mutation detection.

Science.gov (United States)

Autebert, Julien; Coudert, Benoit; Champ, Jérôme; Saias, Laure; Guneri, Ezgi Tulukcuoglu; Lebofsky, Ronald; Bidard, François-Clément; Pierga, Jean-Yves; Farace, Françoise; Descroix, Stéphanie; Malaquin, Laurent; Viovy, Jean-Louis

2015-05-07

A new generation of the Ephesia cell capture technology optimized for CTC capture and genetic analysis is presented, characterized in depth and compared with the CellSearch system as a reference. This technology uses magnetic particles bearing tumour-cell specific EpCAM antibodies, self-assembled in a regular array in a microfluidic flow cell. 48,000 high aspect-ratio columns are generated using a magnetic field in a high throughput (>3 ml h(-1)) device and act as sieves to specifically capture the cells of interest through antibody-antigen interactions. Using this device optimized for CTC capture and analysis, we demonstrated the capture of epithelial cells with capture efficiency above 90% for concentrations as low as a few cells per ml. We showed the high specificity of capture with only 0.26% of non-epithelial cells captured for concentrations above 10 million cells per ml. We investigated the capture behavior of cells in the device, and correlated the cell attachment rate with the EpCAM expression on the cell membranes for six different cell lines. We developed and characterized a two-step blood processing method to allow for rapid processing of 10 ml blood tubes in less than 4 hours, and showed a capture rate of 70% for as low as 25 cells spiked in 10 ml blood tubes, with less than 100 contaminating hematopoietic cells. Using this device and procedure, we validated our system on patient samples using an automated cell immunostaining procedure and a semi-automated cell counting method. Our device captured CTCs in 75% of metastatic prostate cancer patients and 80% of metastatic breast cancer patients, and showed similar or better results than the CellSearch device in 10 out of 13 samples. Finally, we demonstrated the possibility of detecting cancer-related PIK3CA gene mutation in 20 cells captured in the chip with a good correlation between the cell count and the quantitation value Cq of the post-capture qPCR.

ALGORITHM FOR SORTING GROUPED DATA

Science.gov (United States)

Evans, J. D.

1994-01-01

It is often desirable to sort data sets in ascending or descending order. This becomes more difficult for grouped data, i.e., multiple sets of data, where each set of data involves several measurements or related elements. The sort becomes increasingly cumbersome when more than a few elements exist for each data set. In order to achieve an efficient sorting process, an algorithm has been devised in which the maximum most significant element is found, and then compared to each element in succession. The program was written to handle the daily temperature readings of the Voyager spacecraft, particularly those related to the special tracking requirements of Voyager 2. By reducing each data set to a single representative number, the sorting process becomes very easy. The first step in the process is to reduce the data set of width 'n' to a data set of width '1'. This is done by representing each data set by a polynomial of length 'n' based on the differences of the maximum and minimum elements. These single numbers are then sorted and converted back to obtain the original data sets. Required input data are the name of the data file to read and sort, and the starting and ending record numbers. The package includes a sample data file, containing 500 sets of data with 5 elements in each set. This program will perform a sort of the 500 data sets in 3 - 5 seconds on an IBM PC-AT with a hard disk; on a similarly equipped IBM PC-XT the time is under 10 seconds. This program is written in BASIC (specifically the Microsoft QuickBasic compiler) for interactive execution and has been implemented on the IBM PC computer series operating under PC-DOS with a central memory requirement of approximately 40K of 8 bit bytes. A hard disk is desirable for speed considerations, but is not required. This program was developed in 1986.

Magnetic and Engineering Analysis of an Adjustable Strength Permanent Magnet Quadrupole

CERN Document Server

Gottschalk, Stephen C

2005-01-01

Magnetic and engineering analyses used in the design of an adjustable strength permanent magnet quadrupole will be reported. The quadrupole designed has a pole length of 42cm, aperture diameter 13mm, peak pole tip strength 1.03Tesla and peak integrated gradient * length (GL) of 68.7Tesla. Analyses of magnetic strength, field quality, magnetic centerline, temperature compensation and dynamic eddy currents induced during field adjustments will be presented. Magnet sorting strategies, pole positioning sensitivity, component forces, and other sensitivity analyses will be presented. Engineering analyses of stress, deflection and thermal effects as well as compensation strategies will also be shown.

Magnetic resonance investigation of magnetic-labeled baker's yeast cells

International Nuclear Information System (INIS)

Godoy Morais, J.P.M.; Azevedo, R.B.; Silva, L.P.; Lacava, Z.G.M.; Bao, S.N.; Silva, O.; Pelegrini, F.; Gansau, C.; Buske, N.; Safarik, I.; Safarikova, M.; Morais, P.C.

2004-01-01

In this study, the interaction of DMSA-coated magnetite nanoparticles (5 and 10 nm core-size) with Saccharomyces cerevisae was investigated using magnetic resonance (MR) and transmission electron microscopy (TEM). The TEM micrographs revealed magnetite nanoparticles attached externally to the cell wall. The MR data support the strong interaction among the nanoparticles supported by the cells. A remarkable shift in the resonance field was used as signature of particle attachment to the cell wall

Parallel integer sorting with medium and fine-scale parallelism

Science.gov (United States)

Dagum, Leonardo

1993-01-01

Two new parallel integer sorting algorithms, queue-sort and barrel-sort, are presented and analyzed in detail. These algorithms do not have optimal parallel complexity, yet they show very good performance in practice. Queue-sort designed for fine-scale parallel architectures which allow the queueing of multiple messages to the same destination. Barrel-sort is designed for medium-scale parallel architectures with a high message passing overhead. The performance results from the implementation of queue-sort on a Connection Machine CM-2 and barrel-sort on a 128 processor iPSC/860 are given. The two implementations are found to be comparable in performance but not as good as a fully vectorized bucket sort on the Cray YMP.

Effects of high-gradient magnetic fields on living cell machinery

International Nuclear Information System (INIS)

Zablotskii, V; Lunov, O; Kubinova, S; Polyakova, T; Dejneka, A; Sykova, E

2016-01-01

A general interest in biomagnetic effects is related to fundamental studies of the influence of magnetic fields on living objects on the cellular and whole organism levels. Emerging technologies offer new directions for the use of high-gradient magnetic fields to control cell machinery and to understand the intracellular biological processes of the emerging field of nanomedicine. In this review we aim at highlighting recent advances made in identifying fundamental mechanisms by which magnetic gradient forces act on cell fate specification and cell differentiation. The review also provides an analysis of the currently available magnetic systems capable of generating magnetic fields with spatial gradients of up to 10 MT m −1 , with the focus on their suitability for use in cell therapy. Relationships between experimental factors and underlying biophysical mechanisms and assumptions that would ultimately lead to a deeper understanding of cell machinery and the development of more predictive models for the evaluation of the effects of magnetic fields on cells, tissue and organisms are comprehensively discussed. (topical review)

Magnetophoretic transistors in a tri-axial magnetic field.

Science.gov (United States)

Abedini-Nassab, Roozbeh; Joh, Daniel Y; Albarghouthi, Faris; Chilkoti, Ashutosh; Murdoch, David M; Yellen, Benjamin B

2016-10-18

The ability to direct and sort individual biological and non-biological particles into spatially addressable locations is fundamentally important to the emerging field of single cell biology. Towards this goal, we demonstrate a new class of magnetophoretic transistors, which can switch single magnetically labeled cells and magnetic beads between different paths in a microfluidic chamber. Compared with prior work on magnetophoretic transistors driven by a two-dimensional in-plane rotating field, the addition of a vertical magnetic field bias provides significant advantages in preventing the formation of particle clumps and in better replicating the operating principles of circuits in general. However, the three-dimensional driving field requires a complete redesign of the magnetic track geometry and switching electrodes. We have solved this problem by developing several types of transistor geometries which can switch particles between two different tracks by either presenting a local energy barrier or by repelling magnetic objects away from a given track, hereby denoted as "barrier" and "repulsion" transistors, respectively. For both types of transistors, we observe complete switching of magnetic objects with currents of ∼40 mA, which is consistent over a range of particle sizes (8-15 μm). The switching efficiency was also tested at various magnetic field strengths (50-90 Oe) and driving frequencies (0.1-0.6 Hz); however, we again found that the device performance only weakly depended on these parameters. These findings support the use of these novel transistor geometries to form circuit architectures in which cells can be placed in defined locations and retrieved on demand.

UCSD SORT Test (U-SORT): Examination of a newly developed organizational skills assessment tool for severely mentally ill adults.

Science.gov (United States)

Tiznado, Denisse; Mausbach, Brent T; Cardenas, Veronica; Jeste, Dilip V; Patterson, Thomas L

2010-12-01

The present investigation examined the validity of a new cognitive test intended to assess organizational skills. Participants were 180 middle-aged or older participants with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of schizophrenia or schizoaffective disorder. Participants' organizational skills were measured using our newly developed University of California, San Diego Sorting Test (U-SORT), a performance-based test of organizational ability in which subjects sort objects (e.g., battery, pens) from a "junk drawer" into "keep" versus "trash" piles. Significant correlations between U-SORT scores and theoretically similar constructs (i.e. functional capacity, cognitive functioning, and clinical symptoms) were acceptable (mean r = 0.34), and weak correlations were found between U-SORT scores and theoretically dissimilar constructs (e.g., health symptoms, social support, gender; mean r = 0.06 ). The correlation between assessment scores provides preliminary support for the U-SORT test as a brief, easily transportable, reliable, and valid measure of functioning for this population.

How a High-Gradient Magnetic Field Could Affect Cell Life

Science.gov (United States)

Zablotskii, Vitalii; Polyakova, Tatyana; Lunov, Oleg; Dejneka, Alexandr

2016-01-01

The biological effects of high-gradient magnetic fields (HGMFs) have steadily gained the increased attention of researchers from different disciplines, such as cell biology, cell therapy, targeted stem cell delivery and nanomedicine. We present a theoretical framework towards a fundamental understanding of the effects of HGMFs on intracellular processes, highlighting new directions for the study of living cell machinery: changing the probability of ion-channel on/off switching events by membrane magneto-mechanical stress, suppression of cell growth by magnetic pressure, magnetically induced cell division and cell reprograming, and forced migration of membrane receptor proteins. By deriving a generalized form for the Nernst equation, we find that a relatively small magnetic field (approximately 1 T) with a large gradient (up to 1 GT/m) can significantly change the membrane potential of the cell and thus have a significant impact on not only the properties and biological functionality of cells but also cell fate. PMID:27857227

How a High-Gradient Magnetic Field Could Affect Cell Life

Science.gov (United States)

Zablotskii, Vitalii; Polyakova, Tatyana; Lunov, Oleg; Dejneka, Alexandr

2016-11-01

The biological effects of high-gradient magnetic fields (HGMFs) have steadily gained the increased attention of researchers from different disciplines, such as cell biology, cell therapy, targeted stem cell delivery and nanomedicine. We present a theoretical framework towards a fundamental understanding of the effects of HGMFs on intracellular processes, highlighting new directions for the study of living cell machinery: changing the probability of ion-channel on/off switching events by membrane magneto-mechanical stress, suppression of cell growth by magnetic pressure, magnetically induced cell division and cell reprograming, and forced migration of membrane receptor proteins. By deriving a generalized form for the Nernst equation, we find that a relatively small magnetic field (approximately 1 T) with a large gradient (up to 1 GT/m) can significantly change the membrane potential of the cell and thus have a significant impact on not only the properties and biological functionality of cells but also cell fate.

Categorizing Variations of Student-Implemented Sorting Algorithms

Science.gov (United States)

Taherkhani, Ahmad; Korhonen, Ari; Malmi, Lauri

2012-01-01

In this study, we examined freshmen students' sorting algorithm implementations in data structures and algorithms' course in two phases: at the beginning of the course before the students received any instruction on sorting algorithms, and after taking a lecture on sorting algorithms. The analysis revealed that many students have insufficient…

Cell behaviors on magnetic electrospun poly-D, L-lactide nanofibers

International Nuclear Information System (INIS)

Li, Long; Yang, Guang; Li, Jinrong; Ding, Shan; Zhou, Shaobing

2014-01-01

It is widely accepted that magnetic fields have an influence on cell behaviors, but the effects are still not very clear since the magnetic field's type, intensity and exposure time are different. In this study, a static magnetic field (SMF) in moderate intensity (10 mT) was employed to investigate its effect on osteoblast and 3T3 fibroblast cell behaviors cultured respectively with magnetic polymer nanofiber mats. The magnetic mats composed of random oriented or aligned polymer nanofibers were fabricated by electrospinning the mixed solution of poly-D, L-lactide (PLA) and iron oxide nanoparticles. The fiber morphology was characterized by scanning electron microscopy (SEM), the nanoparticle distribution in fiber matrix was measured with transmission electron microscope (TEM). Mechanical properties of nanofiber mats are studied by uniaxial tensile test. The results showed the nanofibers loaded with magnetic nanoparticles displayed excellent magnetic responsibility and biodegradability. In vitro cytotoxicity analysis demonstrated that the osteoblast proliferation of all fiber mats stimulated with or without SMF was increased with the increase of the culturing days. Furthermore, in the horizontal SMFs, cell orientation tended to deviate from nanofiber orientation to field direction while the nanofiber orientation is perpendicular to the field direction, while the horizonal direction of SMFs could also direct the cell growth orientation. The magnetic nanofiber mats provide a potential platform to explore the cell behaviors under the stimulation of external magnetic field. - Highlights: • The random oriented and aligned magnetic electrospun nanofibers were prepared. • The nanofibers displayed excellent magnetic responsibility and biodegradability. • The horizonal direction of SMFs could also direct the cell growth orientation

On the Construction of Sorted Reactive Systems

DEFF Research Database (Denmark)

Birkedal, Lars; Debois, Søren; Hildebrandt, Thomas

2008-01-01

We develop a theory of sorted bigraphical reactive systems. Every application of bigraphs in the literature has required an extension, a sorting, of pure bigraphs. In turn, every such application has required a redevelopment of the theory of pure bigraphical reactive systems for the sorting at hand...... bigraphs. Technically, we give our construction for ordinary reactive systems, then lift it to bigraphical reactive systems. As such, we give also a construction of sortings for ordinary reactive systems. This construction is an improvement over previous attempts in that it produces smaller and much more...

Magnetic domain wall conduits for single cell applications

DEFF Research Database (Denmark)

Donolato, Marco; Torti, A.; Kostesha, Natalie

2011-01-01

The ability to trap, manipulate and release single cells on a surface is important both for fundamental studies of cellular processes and for the development of novel lab-on-chip miniaturized tools for biological and medical applications. In this paper we demonstrate how magnetic domain walls...... walls over 16 hours. Moreover, we demonstrate the controlled transport and release of individual yeast cells via displacement and annihilation of individual domain walls in micro- and nano-sized magnetic structures. These results pave the way to the implementation of magnetic devices based on domain...... walls technology in lab-on-chip systems devoted to accurate individual cell trapping and manipulation....

Advanced cell therapies: targeting, tracking and actuation of cells with magnetic particles.

Science.gov (United States)

Connell, John J; Patrick, P Stephen; Yu, Yichao; Lythgoe, Mark F; Kalber, Tammy L

2015-01-01

Regenerative medicine would greatly benefit from a new platform technology that enabled measurable, controllable and targeting of stem cells to a site of disease or injury in the body. Superparamagnetic iron-oxide nanoparticles offer attractive possibilities in biomedicine and can be incorporated into cells, affording a safe and reliable means of tagging. This review describes three current and emerging methods to enhance regenerative medicine using magnetic particles to guide therapeutic cells to a target organ; track the cells using MRI and assess their spatial localization with high precision and influence the behavior of the cell using magnetic actuation. This approach is complementary to the systemic injection of cell therapies, thus expanding the horizon of stem cell therapeutics.

Implementation of Serial and Parallel Bubble Sort on Fpga

OpenAIRE

Purnomo, Dwi Marhaendro Jati; Arinaldi, Ahmad; Priyantini, Dwi Teguh; Wibisono, Ari; Febrian, Andreas

2016-01-01

Sorting is common process in computational world. Its utilization are on many fields from research to industry. There are many sorting algorithm in nowadays. One of the simplest yet powerful is bubble sort. In this study, bubble sort is implemented on FPGA. The implementation was taken on serial and parallel approach. Serial and parallel bubble sort then compared by means of its memory, execution time, and utility which comprises slices and LUTs. The experiments show that serial bubble sort r...

A cargo-sorting DNA robot.

Science.gov (United States)

Thubagere, Anupama J; Li, Wei; Johnson, Robert F; Chen, Zibo; Doroudi, Shayan; Lee, Yae Lim; Izatt, Gregory; Wittman, Sarah; Srinivas, Niranjan; Woods, Damien; Winfree, Erik; Qian, Lulu

2017-09-15

Two critical challenges in the design and synthesis of molecular robots are modularity and algorithm simplicity. We demonstrate three modular building blocks for a DNA robot that performs cargo sorting at the molecular level. A simple algorithm encoding recognition between cargos and their destinations allows for a simple robot design: a single-stranded DNA with one leg and two foot domains for walking, and one arm and one hand domain for picking up and dropping off cargos. The robot explores a two-dimensional testing ground on the surface of DNA origami, picks up multiple cargos of two types that are initially at unordered locations, and delivers them to specified destinations until all molecules are sorted into two distinct piles. The robot is designed to perform a random walk without any energy supply. Exploiting this feature, a single robot can repeatedly sort multiple cargos. Localization on DNA origami allows for distinct cargo-sorting tasks to take place simultaneously in one test tube or for multiple robots to collectively perform the same task. Copyright © 2017, American Association for the Advancement of Science.

Detection of molecules and cells using nuclear magnetic resonance with magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Rümenapp, Christine, E-mail: ruemenapp@tum.de [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany); Gleich, Bernhard [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany); Mannherz, Hans Georg [Abteilung für Anatomie und Molekulare Embryologie, Ruhr Universität Bochum, Bochum (Germany); Haase, Axel [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany)

2015-04-15

For the detection of small molecules, proteins or even cells in vitro, functionalised magnetic nanoparticles and nuclear magnetic resonance measurements can be applied. In this work, magnetic nanoparticles with the size of 5–7 nm were functionalised with antibodies to detect two model systems of different sizes, the protein avidin and Saccharomyces cerevisiae as the model organism. The synthesised magnetic nanoparticles showed a narrow size distribution, which was determined using transmission electron microscopy and dynamic light scattering. The magnetic nanoparticles were functionalised with the according antibodies via EDC/NHS chemistry. The binding of the antigen to magnetic nanoparticles was detected through the change in the NMR T{sub 2} relaxation time at 0.5 T (≈21.7 MHz). In case of a specific binding the particles cluster and the T{sub 2} relaxation time of the sample changes. The detection limit in buffer for FITC-avidin was determined to be 1.35 nM and 10{sup 7} cells/ml for S. cerevisiae. For fluorescent microscopy the avidin molecules were labelled with FITC and for the detection of S. cerevisiae the magnetic nanoparticles were additionally functionalised with rhodamine. The binding of the particles to S. cerevisiae and the resulting clustering was also seen by transmission electron microscopy.

Magnet Schools, Innate Talent and Social Justice

Science.gov (United States)

Vopat, Mark C.

2011-01-01

Beginning in the 1970s, many school US school districts reallocated their already scarce resources from local schools to specially created magnet schools. Many of these magnet schools have some sort of entrance exam, portfolio, or audition requirement that students must pass in order to gain admission. These selective magnet schools are predicated…

New age radiometric ore sorting - the elegant solution

International Nuclear Information System (INIS)

Gordon, H.P.; Heuer, T.

2000-01-01

Radiometric ore sorting technology and application are described in two parts. Part I reviews the history of radiometric sorting in the minerals industry and describes the latest developments in radiometric sorting technology. Part II describes the history, feasibility study and approach used in the application of the new technology at Rossing Uranium Limited. There has been little progress in the field of radiometric sorting since the late 1970s. This has changed with the development of a high capacity radiometric sorter designed to operate on low-grade ore in the +75mm / -300mm size fraction. This has been designed specifically for an application at Rossing. Rossing has a long history in radiometric sorting dating back to 1968 when initial tests were conducted on the Rossing prospect. Past feasibility studies concluded that radiometric sorting would not conclusively reduce the unit cost of production unless sorting was used to increase production levels. The current feasibility study shows that the application of new radiometric sorter technology makes sorting viable without increasing production, and significantly more attractive with increased production. A pilot approach to confirm sorter performance is described. (author)

Generation of Recombinant Monoclonal Antibodies from Immunised Mice and Rabbits via Flow Cytometry and Sorting of Antigen-Specific IgG+ Memory B Cells.

Directory of Open Access Journals (Sweden)

Dale O Starkie

Full Text Available Single B cell screening strategies, which avoid both hybridoma fusion and combinatorial display, have emerged as important technologies for efficiently sampling the natural antibody repertoire of immunized animals and humans. Having access to a range of methods to interrogate different B cell subsets provides an attractive option to ensure large and diverse panels of high quality antibody are produced. The generation of multiple antibodies and having the ability to find rare B cell clones producing IgG with unique and desirable characteristics facilitates the identification of fit-for-purpose molecules that can be developed into therapeutic agents or research reagents. Here, we describe a multi-parameter flow cytometry single-cell sorting technique for the generation of antigen-specific recombinant monoclonal antibodies from single IgG+ memory B cells. Both mouse splenocytes and rabbit PBMC from immunised animals were used as a source of B cells. Reagents staining both B cells and other unwanted cell types enabled efficient identification of class-switched IgG+ memory B cells. Concurrent staining with antigen labelled separately with two spectrally-distinct fluorophores enabled antigen-specific B cells to be identified, i.e. those which bind to both antigen conjugates (double-positive. These cells were then typically sorted at one cell per well using FACS directly into a 96-well plate containing reverse transcriptase reaction mix. Following production of cDNA, PCR was performed to amplify cognate heavy and light chain variable region genes and generate transcriptionally-active PCR (TAP fragments. These linear expression cassettes were then used directly in a mammalian cell transfection to generate recombinant antibody for further testing. We were able to successfully generate antigen-specific recombinant antibodies from both the rabbit and mouse IgG+ memory B cell subset within one week. This included the generation of an anti-TNFR2 blocking

Life on magnets: stem cell networking on micro-magnet arrays

Czech Academy of Sciences Publication Activity Database

Zablotskyy, Vitaliy A.; Dejneka, Alexandr; Kubinová, Šárka; Le-Roy, D.; Dumas-Bouchiat, F.; Givord, D.; Dempsey, N.; Syková, Eva

2013-01-01

Roč. 8, č. 8 (2013), e70416 E-ISSN 1932-6203 R&D Projects: GA ČR GAP304/11/0653; GA ČR(CZ) GAP304/12/1370 Grant - others:AV ČR(CZ) M100101219 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : micro- magnet * stem cells Subject RIV: BM - Solid Matter Physics ; Magnet ism; FH - Neurology (UEM-P) Impact factor: 3.534, year: 2013

Yeast cells proliferation on various strong static magnetic fields and temperatures

International Nuclear Information System (INIS)

Otabe, E S; Kuroki, S; Nikawa, J; Matsumoto, Y; Ooba, T; Kiso, K; Hayashi, H

2009-01-01

The effect of strong magnetic fields on activities of yeast cells were investigated. Experimental yeast cells were cultured in 5 ml of YPD(Yeast extract Peptone Dextrose) for the number density of yeast cells of 5.0 ±0.2 x 10 6 /ml with various temperatures and magnetic fields up to 10 T. Since the yeast cells were placed in the center of the superconducting magnet, the effect of magnetic force due to the diamagnetism and magnetic gradient was negligibly small. The yeast suspension was opened to air and cultured in shaking condition. The number of yeast cells in the yeast suspension was counted by a counting plate with an optical microscope, and the time dependence of the number density of yeast cells was measured. The time dependence of the number density of yeast cells, ρ, of initial part is analyzed in terms of Malthus equation as given by ρ = ρo exp(kt), where k is the growth coefficient. It is found that, the growth coefficient under the magnetic field is suppressed compared with the control. The growth coefficient decreasing as increasing magnetic field and is saturated at about 5 T. On the other hand, it is found that the suppression of growth of yeast cells by the magnetic field is diminished at high temperatures.

Axon-Axon Interactions Regulate Topographic Optic Tract Sorting via CYFIP2-Dependent WAVE Complex Function.

Science.gov (United States)

Cioni, Jean-Michel; Wong, Hovy Ho-Wai; Bressan, Dario; Kodama, Lay; Harris, William A; Holt, Christine E

2018-03-07

The axons of retinal ganglion cells (RGCs) are topographically sorted before they arrive at the optic tectum. This pre-target sorting, typical of axon tracts throughout the brain, is poorly understood. Here, we show that cytoplasmic FMR1-interacting proteins (CYFIPs) fulfill non-redundant functions in RGCs, with CYFIP1 mediating axon growth and CYFIP2 specifically involved in axon sorting. We find that CYFIP2 mediates homotypic and heterotypic contact-triggered fasciculation and repulsion responses between dorsal and ventral axons. CYFIP2 associates with transporting ribonucleoprotein particles in axons and regulates translation. Axon-axon contact stimulates CYFIP2 to move into growth cones where it joins the actin nucleating WAVE regulatory complex (WRC) in the periphery and regulates actin remodeling and filopodial dynamics. CYFIP2's function in axon sorting is mediated by its binding to the WRC but not its translational regulation. Together, these findings uncover CYFIP2 as a key regulatory link between axon-axon interactions, filopodial dynamics, and optic tract sorting. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

A Comparison of Card-sorting Analysis Methods

DEFF Research Database (Denmark)

Nawaz, Ather

2012-01-01

This study investigates how the choice of analysis method for card sorting studies affects the suggested information structure for websites. In the card sorting technique, a variety of methods are used to analyse the resulting data. The analysis of card sorting data helps user experience (UX......) designers to discover the patterns in how users make classifications and thus to develop an optimal, user-centred website structure. During analysis, the recurrence of patterns of classification between users influences the resulting website structure. However, the algorithm used in the analysis influences...... the recurrent patterns found and thus has consequences for the resulting website design. This paper draws an attention to the choice of card sorting analysis and techniques and shows how it impacts the results. The research focuses on how the same data for card sorting can lead to different website structures...

Track-Etched Magnetic Micropores for Immunomagnetic Isolation of Pathogens

Science.gov (United States)

Muluneh, Melaku; Shang, Wu

2014-01-01

A microfluidic chip is developed to selectively isolate magnetically tagged cells from heterogeneous suspensions, the track-etched magnetic micropore (TEMPO) filter. The TEMPO consists of an ion track-etched polycarbonate membrane coated with soft magnetic film (Ni20Fe80). In the presence of an applied field, provided by a small external magnet, the filter becomes magnetized and strong magnetic traps are created along the edges of the micropores. In contrast to conventional microfluidics, fluid flows vertically through the porous membrane allowing large flow rates while keeping the capture rate high and the chip compact. By utilizing track-etching instead of conventional semiconductor fabrication, TEMPOs can be fabricated with microscale pores over large areas A > 1 cm2 at little cost ( 500 at a flow rate of Φ = 5 mL h−1. Furthermore, the large density of micropores (ρ = 106 cm−2) allows the TEMPO to sort E. coli from unprocessed environmental and clinical samples, as the blockage of a few pores does not significantly change the behavior of the device. PMID:24535921

Using Magnets and Magnetic Beads to Dissect Signaling Pathways Activated by Mechanical Tension Applied to Cells

Science.gov (United States)

Marjoram, R.J.; Guilluy, C; Burridge, K.

2015-01-01

Cellular tension has implications in normal biology and pathology. Membrane adhesion receptors serve as conduits for mechanotransduction that lead to cellular responses. Ligand-conjugated magnetic beads are a useful tool in the study of how cells sense and respond to tension. Here we detail methods for their use in applying tension to cells and strategies for analyzing the results. We demonstrate the methods by analyzing mechanotransduction through VE-cadherin on endothelial cells using both permanent magnets and magnetic tweezers. PMID:26427549

Three Sorts of Naturalism

OpenAIRE

Fink, Hans

2006-01-01

In "Two sorts of Naturalism" John McDowell is sketching his own sort of naturalism in ethics as an alternative to "bald naturalism". In this paper I distinguish materialist, idealist and absolute conceptions of nature and of naturalism in order to provide a framework for a clearer understanding of what McDowell's own naturalism amounts to. I argue that nothing short of an absolute naturalism will do for a number of McDowell's own purposes, but that it is far from obvious that this is his posi...

Bidirectional sorting of flocking particles in the presence of asymmetric barriers.

Science.gov (United States)

Drocco, Jeffrey A; Olson Reichhardt, C J; Reichhardt, C

2012-05-01

We demonstrate numerically bidirectional sorting of flocking particles interacting with an array of V-shaped asymmetric barriers. Each particle aligns with the average swimming direction of its neighbors according to the Vicsek model and experiences additional steric interactions as well as repulsion from the fixed barriers. We show that particles preferentially localize to one side of the barrier array over time and that the direction of this rectification can be reversed by adjusting the particle-particle exclusion radius or the noise term in the equations of motion. These results provide a conceptual basis for isolation and sorting of single-cell and multicellular organisms that move collectively according to flocking-type interaction rules.

Design and characterization of permanent magnetic solenoids for REGAE

International Nuclear Information System (INIS)

Hachmann, M.; Flöttmann, K.; Gehrke, T.; Mayet, F.

2016-01-01

REGAE is a small electron linear accelerator at DESY. In order to focus short and low charged electron bunches down to a few μm permanent magnetic solenoids were designed, assembled and field measurements were done. Due to a shortage of space close to the operation area an in-vacuum solution has been chosen. Furthermore a two-ring design made of wedges has been preferred in terms of beam dynamic issues. To keep the field quality of a piecewise built magnet still high a sorting algorithm for the wedge arrangement including a simple magnetic field model has been developed and used for the construction of the magnets. The magnetic field of these solenoids has been measured with high precision and compared to simulations. - Highlights: • presenting a two-ring radially magnetized permanent magnetic solenoid design. • development of a analytical field description and field quality factor. • development of a sorting algorithm for permanent magnetic pieces to form a magnet. • performing a high-precision field measurement of a high gradient field.

Application of radix sorting in high energy physics experiment

International Nuclear Information System (INIS)

Chen Xuan; Gu Minhao; Zhu Kejun

2012-01-01

In the high energy physics experiments, there are always requirements to sort the large scale of experiment data. To meet the demand, this paper introduces one radix sorting algorithms, whose sub-sort is counting sorting and time complex is O (n), based on the characteristic of high energy physics experiment data that is marked by time stamp. This paper gives the description, analysis, implementation and experimental result of the sorting algorithms. (authors)

Proliferation and chondrogenic differentiation of CD105-positive enriched rat synovium-derived mesenchymal stem cells in three-dimensional porous scaffolds

International Nuclear Information System (INIS)

Qi Jun; Chen Anmin; You Hongbo; Li Kunpeng; Zhang Di; Guo Fengjing

2011-01-01

Stem cell-based tissue engineering has provided an alternative strategy to treat cartilage lesions, and synovium-derived mesenchymal stem cells (SMSCs) are considered as a promising cell source for cartilage repair. In this study, the SMSCs were isolated from rat synovium, and CD105-positive (CD105 + ) cells were enriched using magnetic activated cell sorting. Sorted cells were subsequently seeded onto the chitosan-alginate composite three-dimensional (3D) porous scaffolds and cultured in chondrogenic culture medium in the presence of TGF-β 3 and BMP-2 for 2 weeks in vitro. After 2 weeks in culture, scanning electron microscopy results showed that cells attached and proliferated well on scaffolds, and secreted extracellular matrix were also observed. From day 7 to day 14, the total DNA and glucosaminoglycan content of the cells cultured in scaffolds were found to have increased significantly, and cell cycle analyses revealed that the percentage of cells in the S and G2/M phases increased and the percentage of cells in the G0/G1 phase decreased. Compared with non-sorted cells, the sorted cells cultured in scaffolds underwent more chondrogenic differentiation, as evidenced by higher expression of type II collagen and Sox9 at the protein and mRNA levels. The results suggest that CD105 + enriched SMSCs may be a potential cell source for cartilage tissue engineering, and the chitosan-alginate composite 3D porous scaffold could provide a favorable microenvironment for supporting proliferation and chondrogenic differentiation of cells.

Analytical Formulation of the Electric Field Induced by Electrode Arrays: Towards Automated Dielectrophoretic Cell Sorting

Directory of Open Access Journals (Sweden)

Vladimir Gauthier

2017-08-01

Full Text Available Dielectrophoresis is defined as the motion of an electrically polarisable particle in a non-uniform electric field. Current dielectrophoretic devices enabling sorting of cells are mostly controlled in open-loop applying a predefined voltage on micro-electrodes. Closed-loop control of these devices would enable to get advanced functionalities and also more robust behavior. Currently, the numerical models of dielectrophoretic force are too complex to be used in real-time closed-loop control. The aim of this paper is to propose a new type of models usable in this framework. We propose an analytical model of the electric field based on Fourier series to compute the dielectrophoretic force produced by parallel electrode arrays. Indeed, this method provides an analytical expression of the electric potential which decouples the geometrical factors (parameter of our system, the voltages applied on electrodes (input of our system, and the position of the cells (output of our system. Considering the Newton laws on each cell, it enables to generate easily a dynamic model of the cell positions (output function of the voltages on electrodes (input. This dynamic model of our system is required to design the future closed-loop control law. The predicted dielectrophoretic forces are compared to a numerical simulation based on finite element model using COMSOL software. The model presented in this paper enables to compute the dielectrophoretic force applied to a cell by an electrode array in a few tenths of milliseconds. This model could be consequently used in future works for closed-loop control of dielectrophoretic devices.

Engineering a Cache-Oblivious Sorting Algorithm

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Fagerberg, Rolf; Vinther, Kristoffer

2007-01-01

This paper is an algorithmic engineering study of cache-oblivious sorting. We investigate by empirical methods a number of implementation issues and parameter choices for the cache-oblivious sorting algorithm Lazy Funnelsort, and compare the final algorithm with Quicksort, the established standard...

Magnetic targeting of iron-oxide-labeled fluorescent hepatoma cells to the liver

International Nuclear Information System (INIS)

Luciani, Alain; Wilhelm, Claire; Gazeau, Florence; Bruneval, Patrick; Cunin, Patrick; Autret, Gwennhael; Clement, Olivier; Rahmouni, Alain

2009-01-01

The purpose of this study was to determine whether an external magnet field can induce preferential trafficking of magnetically labeled Huh7 hepatoma cells to the liver following liver cell transplantation. Huh7 hepatoma cells were labeled with anionic magnetic nanoparticles (AMNP) and tagged with a fluorescent membrane marker (PKH67). Iron-uptake was measured by magnetophoresis. Twenty C57Bl6 mice received an intrasplenic injection of 2 x 10 6 labeled cells. An external magnet (0.29 T; 25 T/m) was placed over the liver of 13 randomly selected animals (magnet group), while the remaining 7 animals served as controls. MRI (1.5 T) and confocal fluorescence microscopy (CFM) were performed 10 days post-transplantation. The presence and location of labeled cells within the livers were compared in the magnet group and controls, and confronted with histological analysis representing the standard of reference. Mean iron content per cell was 6 pg. Based on histology, labeled cells were more frequently present within recipient livers in the magnet group (p < 0.01) where their distribution was preferentially peri-vascular (p<0.05). MRI and CFM gave similar results for the overall detection of transplanted cells (kappa=0.828) and for the identification of peri-vascular cells (kappa=0.78). Application of an external magnet can modify the trafficking of transplanted cells, especially by promoting the formation of perivascular aggregates. (orig.)

Biomarker-free dielectrophoretic sorting of differentiating myoblast multipotent progenitor cells and their membrane analysis by Raman spectroscopy.

Science.gov (United States)

Muratore, Massimo; Srsen, Vlastimil; Waterfall, Martin; Downes, Andrew; Pethig, Ronald

2012-09-01

Myoblasts are muscle derived mesenchymal stem cell progenitors that have great potential for use in regenerative medicine, especially for cardiomyogenesis grafts and intracardiac cell transplantation. To utilise such cells for pre-clinical and clinical applications, and especially for personalized medicine, it is essential to generate a synchronised, homogenous, population of cells that display phenotypic and genotypic homogeneity within a population of cells. We demonstrate that the biomarker-free technique of dielectrophoresis (DEP) can be used to discriminate cells between stages of differentiation in the C2C12 myoblast multipotent mouse model. Terminally differentiated myotubes were separated from C2C12 myoblasts to better than 96% purity, a result validated by flow cytometry and Western blotting. To determine the extent to which cell membrane capacitance, rather than cell size, determined the DEP response of a cell, C2C12 myoblasts were co-cultured with GFP-expressing MRC-5 fibroblasts of comparable size distributions (mean diameter ∼10 μm). A DEP sorting efficiency greater than 98% was achieved for these two cell types, a result concluded to arise from the fibroblasts possessing a larger membrane capacitance than the myoblasts. It is currently assumed that differences in membrane capacitance primarily reflect differences in the extent of folding or surface features of the membrane. However, our finding by Raman spectroscopy that the fibroblast membranes contained a smaller proportion of saturated lipids than those of the myoblasts suggests that the membrane chemistry should also be taken into account.

Targeted cancer cell death induced by biofunctionalized magnetic nanowires

KAUST Repository

Contreras, Maria F.; Ravasi, Timothy; Kosel, Jü rgen

2014-01-01

Magnetic micro and nanomaterials are increasingly interesting for biomedical applications since they possess many advantageous properties: they can become biocompatible, they can be functionalized to target specific cells and they can be remotely manipulated by magnetic fields. The goal of this study is to use antibody-functionalized nickel nanowires (Ab-NWs) as an alternative method in cancer therapy overcoming the limitations of current treatments that lack specificity and are highly cytotoxic. Ab-NWs have been incubated with cancer cells and a 12% drop on cell viability was observed for a treatment of only 10 minutes and an alternating magnetic field of low intensity and low frequency. It is believed that the Ab-NWs vibrate transmitting a mechanical force to the targeted cells inducing cell death. © 2014 IEEE.

Targeted cancer cell death induced by biofunctionalized magnetic nanowires

KAUST Repository

Contreras, Maria F.

2014-02-01

Magnetic micro and nanomaterials are increasingly interesting for biomedical applications since they possess many advantageous properties: they can become biocompatible, they can be functionalized to target specific cells and they can be remotely manipulated by magnetic fields. The goal of this study is to use antibody-functionalized nickel nanowires (Ab-NWs) as an alternative method in cancer therapy overcoming the limitations of current treatments that lack specificity and are highly cytotoxic. Ab-NWs have been incubated with cancer cells and a 12% drop on cell viability was observed for a treatment of only 10 minutes and an alternating magnetic field of low intensity and low frequency. It is believed that the Ab-NWs vibrate transmitting a mechanical force to the targeted cells inducing cell death. © 2014 IEEE.

Molecular pathways of early CD105-positive erythroid cells as compared with CD34-positive common precursor cells by flow cytometric cell-sorting and gene expression profiling

International Nuclear Information System (INIS)

Machherndl-Spandl, S; Suessner, S; Danzer, M; Proell, J; Gabriel, C; Lauf, J; Sylie, R; Klein, H-U; Béné, M C; Weltermann, A; Bettelheim, P

2013-01-01

Special attention has recently been drawn to the molecular network of different genes that are responsible for the development of erythroid cells. The aim of the present study was to establish in detail the immunophenotype of early erythroid cells and to compare the gene expression profile of freshly isolated early erythroid precursors with that of the CD34-positive (CD34 + ) compartment. Multiparameter flow cytometric analyses of human bone marrow mononuclear cell fractions (n=20) defined three distinct early erythroid stages. The gene expression profile of sorted early erythroid cells was analyzed by Affymetrix array technology. For 4524 genes, a differential regulation was found in CD105-positive erythroid cells as compared with the CD34 + progenitor compartment (2362 upregulated genes). A highly significant difference was observed in the expression level of genes involved in transcription, heme synthesis, iron and mitochondrial metabolism and transforming growth factor-β signaling. A comparison with recently published data showed over 1000 genes that as yet have not been reported to be upregulated in the early erythroid lineage. The gene expression level within distinct pathways could be illustrated directly by applying the Ingenuity software program. The results of gene expression analyses can be seen at the Gene Expression Omnibus repository

Pulsed Magnetic Field Improves the Transport of Iron Oxide Nanoparticles through Cell Barriers

Science.gov (United States)

Min, Kyoung Ah; Shin, Meong Cheol; Yu, Faquan; Yang, Meizhu; David, Allan E.; Yang, Victor C.; Rosania, Gus R.

2013-01-01

Understanding how a magnetic field affects the interaction of magnetic nanoparticles (MNPs) with cells is fundamental to any potential downstream applications of MNPs as gene and drug delivery vehicles. Here, we present a quantitative analysis of how a pulsed magnetic field influences the manner in which MNPs interact with, and penetrate across a cell monolayer. Relative to a constant magnetic field, the rate of MNP uptake and transport across cell monolayers was enhanced by a pulsed magnetic field. MNP transport across cells was significantly inhibited at low temperature under both constant and pulsed magnetic field conditions, consistent with an active mechanism (i.e. endocytosis) mediating MNP transport. Microscopic observations and biochemical analysis indicated that, in a constant magnetic field, transport of MNPs across the cells was inhibited due to the formation of large (>2 μm) magnetically-induced MNP aggregates, which exceeded the size of endocytic vesicles. Thus, a pulsed magnetic field enhances the cellular uptake and transport of MNPs across cell barriers relative to a constant magnetic field by promoting accumulation while minimizing magnetically-induced MNP aggregates at the cell surface. PMID:23373613

TRAM is involved in IL-18 signaling and functions as a sorting adaptor for MyD88.

Directory of Open Access Journals (Sweden)

Hidenori Ohnishi

Full Text Available MyD88, a Toll/interleukin-1 receptor homology (TIR domain-containing adaptor protein, mediates signals from the Toll-like receptors (TLR or IL-1/IL-18 receptors to downstream kinases. In MyD88-dependent TLR4 signaling, the function of MyD88 is enhanced by another TIR domain-containing adaptor, Mal/TIRAP, which brings MyD88 to the plasma membrane and promotes its interaction with the cytosolic region of TLR4. Hence, Mal is recognized as the "sorting adaptor" for MyD88. In this study, a direct interaction between MyD88-TIR and another membrane-sorting adaptor, TRAM/TICAM-2, was demonstrated in vitro. Cell-based assays including RNA interference experiments and TRAM deficient mice revealed that the interplay between MyD88 and TRAM in cells is important in mediating IL-18 signal transduction. Live cell imaging further demonstrated the co-localized accumulation of MyD88 and TRAM in the membrane regions in HEK293 cells. These findings suggest that TRAM serves as the sorting adaptor for MyD88 in IL-18 signaling, which then facilitates the signal transduction. The binding sites for TRAM are located in the TIR domain of MyD88 and actually overlap with the binding sites for Mal. MyD88, the multifunctional signaling adaptor that works together with most of the TLR members and with the IL-1/IL-18 receptors, can interact with two distinct sorting adaptors, TRAM and Mal, in a conserved manner in a distinct context.

Magnetically insulated fission electric cells for direct energy conversion

International Nuclear Information System (INIS)

Slutz, S.A.; Seidel, D.B.; Lipinski, R.J.; Rochau, G.E.; Brown, L.C.

2003-01-01

The principles of fission electric cells are reviewed. A detailed Monte Carlo model of the efficiency of a fission electric cell is presented and a theory of magnetically insulated fission electric cells (MIFECs) is developed. It is shown that the low operating voltages observed in previous MIFEC experiments were due to nonoptimal magnetic field profiles. Improved magnetic field profiles are presented. It is further shown that the large electric field present in a MIFEC limits the structure of the cathode and can lead to a displacement instability of the cathode toward the anode. This instability places constraints on the number of cells that can be strung together without some external cathode support. The large electric field stress also leads to electrical surface breakdown of the cathode. It is shown that this leads to the formation of a virtual cathode resulting in geometry constraints for spherical cells. Finally it is shown that the requirements of magnetic insulation and high efficiency leads to very low average density of the fissile material. Thus a reactor using fission electric cells for efficient direct energy conversion will be large and require a very large number of cells. This could be mitigated somewhat by the use of exotic fuels

Porcine Dental Epithelial Cells Differentiated in a Cell Sheet Constructed by Magnetic Nanotechnology

Directory of Open Access Journals (Sweden)

Wataru Koto

2017-10-01

Full Text Available Magnetic nanoparticles (MNPs are widely used in medical examinations, treatments, and basic research, including magnetic resonance imaging, drug delivery systems, and tissue engineering. In this study, MNPs with magnetic force were applied to tissue engineering for dental enamel regeneration. The internalization of MNPs into the odontogenic cells was observed by transmission electron microscopy. A combined cell sheet consisting of dental epithelial cells (DECs and dental mesenchymal cells (DMCs (CC sheet was constructed using magnetic force-based tissue engineering technology. The result of the iron staining indicated that MNPs were distributed ubiquitously over the CC sheet. mRNA expression of enamel differentiation and basement membrane markers was examined in the CC sheet. Immunostaining showed Collagen IV expression at the border region between DEC and DMC layers in the CC sheet. These results revealed that epithelial–mesenchymal interactions between DEC and DMC layers were caused by bringing DECs close to DMCs mechanically by magnetic force. Our study suggests that the microenvironment in the CC sheet might be similar to that during the developmental stage of a tooth bud. In conclusion, a CC sheet employing MNPs could be developed as a novel and unique graft for artificially regenerating dental enamel.

Magnetization Dynamics in Two Novel Current-Driven Spintronic Memory Cell Structures

KAUST Repository

Velazquez-Rizo, Martin

2017-07-01

In this work, two new spintronic memory cell structures are proposed. The first cell uses the diffusion of polarized spins into ferromagnets with perpendicular anisotropy to tilt their magnetization followed by their dipolar coupling to a fixed magnet (Bhowmik et al., 2014). The possibility of setting the magnetization to both stable magnetization states in a controlled manner using a similar concept remains unknown, but the proposed structure poses to be a solution to this difficulty. The second cell proposed takes advantage of the multiple stable magnetic states that exist in ferromagnets with configurational anisotropy and also uses spin torques to manipulate its magnetization. It utilizes a square-shaped ferromagnet whose stable magnetization has preferred directions along the diagonals of the square, giving four stable magnetic states allowing to use the structure as a multi-bit memory cell. Both devices use spin currents generated in heavy metals by the Spin Hall effect present in these materials. Among the advantages of the structures proposed are their inherent non-volatility and the fact that there is no need for applying external magnetic fields during their operation, which drastically improves the energy efficiency of the devices. Computational simulations using the Object Oriented Micromagnetic Framework (OOMMF) software package were performed to study the dynamics of the magnetization process in both structures and predict their behavior. Besides, we fabricated a 4-terminal memory cell with configurational anisotropy similar to the device proposed, and found four stable resistive states on the structure, proving the feasibility of this technology for implementation of high-density, non-volatile memory cells.

On the Directly and Subdirectly Irreducible Many-Sorted Algebras

Directory of Open Access Journals (Sweden)

Climent Vidal J.

2015-03-01

Full Text Available A theorem of single-sorted universal algebra asserts that every finite algebra can be represented as a product of a finite family of finite directly irreducible algebras. In this article, we show that the many-sorted counterpart of the above theorem is also true, but under the condition of requiring, in the definition of directly reducible many-sorted algebra, that the supports of the factors should be included in the support of the many-sorted algebra. Moreover, we show that the theorem of Birkhoff, according to which every single-sorted algebra is isomorphic to a subdirect product of subdirectly irreducible algebras, is also true in the field of many-sorted algebras.

Magnetic targeting of iron-oxide-labeled fluorescent hepatoma cells to the liver

Energy Technology Data Exchange (ETDEWEB)

Luciani, Alain [Universite Rene Descartes, Hopital Europeen Georges Pompidou, Laboratoire de Recherche en Imagerie, EA 4062, Paris (France); Imagerie Medicale, Faculte de Medecine Paris XII, CHU Henri Mondor, Creteil cedex (France); Wilhelm, Claire; Gazeau, Florence [Universite Paris Diderot, Batiment Condorcet, Laboratoire Matiere et Systemes Complexes, CNRS-UMR 7057, Paris Cedex (France); Bruneval, Patrick [Anatomopathologie, Hopital Europeen Georges Pompidou, Paris (France); Cunin, Patrick [Unite de Recherche Clinique, Faculte de Medecine Paris XII, CHU Henri Mondor, Creteil cedex (France); Autret, Gwennhael; Clement, Olivier [Universite Rene Descartes, Hopital Europeen Georges Pompidou, Laboratoire de Recherche en Imagerie, EA 4062, Paris (France); Rahmouni, Alain [Imagerie Medicale, Faculte de Medecine Paris XII, CHU Henri Mondor, Creteil cedex (France)

2009-05-15

The purpose of this study was to determine whether an external magnet field can induce preferential trafficking of magnetically labeled Huh7 hepatoma cells to the liver following liver cell transplantation. Huh7 hepatoma cells were labeled with anionic magnetic nanoparticles (AMNP) and tagged with a fluorescent membrane marker (PKH67). Iron-uptake was measured by magnetophoresis. Twenty C57Bl6 mice received an intrasplenic injection of 2 x 10{sup 6} labeled cells. An external magnet (0.29 T; 25 T/m) was placed over the liver of 13 randomly selected animals (magnet group), while the remaining 7 animals served as controls. MRI (1.5 T) and confocal fluorescence microscopy (CFM) were performed 10 days post-transplantation. The presence and location of labeled cells within the livers were compared in the magnet group and controls, and confronted with histological analysis representing the standard of reference. Mean iron content per cell was 6 pg. Based on histology, labeled cells were more frequently present within recipient livers in the magnet group (p < 0.01) where their distribution was preferentially peri-vascular (p<0.05). MRI and CFM gave similar results for the overall detection of transplanted cells (kappa=0.828) and for the identification of peri-vascular cells (kappa=0.78). Application of an external magnet can modify the trafficking of transplanted cells, especially by promoting the formation of perivascular aggregates. (orig.)

Effects of high-gradient magnetic fields on living cell machinery

Czech Academy of Sciences Publication Activity Database

Zablotskyy, V.; Lunov, O.; Kubinová, Šárka; Polyakova, T.; Syková, Eva; Dejneka, A.

2016-01-01

Roč. 49, č. 2016 (2016), s. 493003 ISSN 0022-3727 R&D Projects: GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : living cell * magnetic gradient force * cell mechanics * stem cell * magnetic field Subject RIV: FP - Other Medical Disciplines Impact factor: 2.588, year: 2016

Order-sorted Algebraic Specifications with Higher-order Functions

DEFF Research Database (Denmark)

Haxthausen, Anne Elisabeth

1995-01-01

This paper gives a proposal for how order-sorted algebraic specification languages can be extended with higher-order functions. The approach taken is a generalisation to the order-sorted case of an approach given by Mller, Tarlecki and Wirsing for the many-sorted case. The main idea in the proposal...

Sorting and sustaining cooperation

DEFF Research Database (Denmark)

Vikander, Nick

2013-01-01

This paper looks at cooperation in teams where some people are selfish and others are conditional cooperators, and where lay-offs will occur at a fixed future date. I show that the best way to sustain cooperation prior to the lay-offs is often in a sorting equilibrium, where conditional cooperators...... can identify and then work with one another. Changes to parameters that would seem to make cooperation more attractive, such as an increase in the discount factor or the fraction of conditional cooperators, can reduce equilibrium cooperation if they decrease a selfish player's incentive to sort....

A Simple Deep Learning Method for Neuronal Spike Sorting

Science.gov (United States)

Yang, Kai; Wu, Haifeng; Zeng, Yu

2017-10-01

Spike sorting is one of key technique to understand brain activity. With the development of modern electrophysiology technology, some recent multi-electrode technologies have been able to record the activity of thousands of neuronal spikes simultaneously. The spike sorting in this case will increase the computational complexity of conventional sorting algorithms. In this paper, we will focus spike sorting on how to reduce the complexity, and introduce a deep learning algorithm, principal component analysis network (PCANet) to spike sorting. The introduced method starts from a conventional model and establish a Toeplitz matrix. Through the column vectors in the matrix, we trains a PCANet, where some eigenvalue vectors of spikes could be extracted. Finally, support vector machine (SVM) is used to sort spikes. In experiments, we choose two groups of simulated data from public databases availably and compare this introduced method with conventional methods. The results indicate that the introduced method indeed has lower complexity with the same sorting errors as the conventional methods.

Denni Algorithm An Enhanced Of SMS (Scan, Move and Sort) Algorithm

Science.gov (United States)

Aprilsyah Lubis, Denni; Salim Sitompul, Opim; Marwan; Tulus; Andri Budiman, M.

2017-12-01

Sorting has been a profound area for the algorithmic researchers, and many resources are invested to suggest a more working sorting algorithm. For this purpose many existing sorting algorithms were observed in terms of the efficiency of the algorithmic complexity. Efficient sorting is important to optimize the use of other algorithms that require sorted lists to work correctly. Sorting has been considered as a fundamental problem in the study of algorithms that due to many reasons namely, the necessary to sort information is inherent in many applications, algorithms often use sorting as a key subroutine, in algorithm design there are many essential techniques represented in the body of sorting algorithms, and many engineering issues come to the fore when implementing sorting algorithms., Many algorithms are very well known for sorting the unordered lists, and one of the well-known algorithms that make the process of sorting to be more economical and efficient is SMS (Scan, Move and Sort) algorithm, an enhancement of Quicksort invented Rami Mansi in 2010. This paper presents a new sorting algorithm called Denni-algorithm. The Denni algorithm is considered as an enhancement on the SMS algorithm in average, and worst cases. The Denni algorithm is compared with the SMS algorithm and the results were promising.

A novel automated spike sorting algorithm with adaptable feature extraction.

Science.gov (United States)

Bestel, Robert; Daus, Andreas W; Thielemann, Christiane

2012-10-15

To study the electrophysiological properties of neuronal networks, in vitro studies based on microelectrode arrays have become a viable tool for analysis. Although in constant progress, a challenging task still remains in this area: the development of an efficient spike sorting algorithm that allows an accurate signal analysis at the single-cell level. Most sorting algorithms currently available only extract a specific feature type, such as the principal components or Wavelet coefficients of the measured spike signals in order to separate different spike shapes generated by different neurons. However, due to the great variety in the obtained spike shapes, the derivation of an optimal feature set is still a very complex issue that current algorithms struggle with. To address this problem, we propose a novel algorithm that (i) extracts a variety of geometric, Wavelet and principal component-based features and (ii) automatically derives a feature subset, most suitable for sorting an individual set of spike signals. Thus, there is a new approach that evaluates the probability distribution of the obtained spike features and consequently determines the candidates most suitable for the actual spike sorting. These candidates can be formed into an individually adjusted set of spike features, allowing a separation of the various shapes present in the obtained neuronal signal by a subsequent expectation maximisation clustering algorithm. Test results with simulated data files and data obtained from chick embryonic neurons cultured on microelectrode arrays showed an excellent classification result, indicating the superior performance of the described algorithm approach. Copyright © 2012 Elsevier B.V. All rights reserved.

Particle sorting by Paramecium cilia arrays.

Science.gov (United States)

Mayne, Richard; Whiting, James G H; Wheway, Gabrielle; Melhuish, Chris; Adamatzky, Andrew

Motile cilia are cell-surface organelles whose purposes, in ciliated protists and certain ciliated metazoan epithelia, include generating fluid flow, sensing and substance uptake. Certain properties of cilia arrays, such as beating synchronisation and manipulation of external proximate particulate matter, are considered emergent, but remain incompletely characterised despite these phenomena having being the subject of extensive modelling. This study constitutes a laboratory experimental characterisation of one of the emergent properties of motile cilia: manipulation of adjacent particulates. The work demonstrates through automated videomicrographic particle tracking that interactions between microparticles and somatic cilia arrays of the ciliated model organism Paramecium caudatum constitute a form of rudimentary 'sorting'. Small particles are drawn into the organism's proximity by cilia-induced fluid currents at all times, whereas larger particles may be held immobile at a distance from the cell margin when the cell generates characteristic feeding currents in the surrounding media. These findings can contribute to the design and fabrication of biomimetic cilia, with potential applications to the study of ciliopathies. Copyright © 2017 Elsevier B.V. All rights reserved.

The solution space of sorting by DCJ.

Science.gov (United States)

Braga, Marília D V; Stoye, Jens

2010-09-01

In genome rearrangements, the double cut and join (DCJ) operation, introduced by Yancopoulos et al. in 2005, allows one to represent most rearrangement events that could happen in multichromosomal genomes, such as inversions, translocations, fusions, and fissions. No restriction on the genome structure considering linear and circular chromosomes is imposed. An advantage of this general model is that it leads to considerable algorithmic simplifications compared to other genome rearrangement models. Recently, several works concerning the DCJ operation have been published, and in particular, an algorithm was proposed to find an optimal DCJ sequence for sorting one genome into another one. Here we study the solution space of this problem and give an easy-to-compute formula that corresponds to the exact number of optimal DCJ sorting sequences for a particular subset of instances of the problem. We also give an algorithm to count the number of optimal sorting sequences for any instance of the problem. Another interesting result is the demonstration of the possibility of obtaining one optimal sorting sequence by properly replacing any pair of consecutive operations in another optimal sequence. As a consequence, any optimal sorting sequence can be obtained from one other by applying such replacements successively, but the problem of finding the shortest number of replacements between two sorting sequences is still open.

The EARP Complex and Its Interactor EIPR-1 Are Required for Cargo Sorting to Dense-Core Vesicles.

Directory of Open Access Journals (Sweden)

Irini Topalidou

2016-05-01

Full Text Available The dense-core vesicle is a secretory organelle that mediates the regulated release of peptide hormones, growth factors, and biogenic amines. Dense-core vesicles originate from the trans-Golgi of neurons and neuroendocrine cells, but it is unclear how this specialized organelle is formed and acquires its specific cargos. To identify proteins that act in dense-core vesicle biogenesis, we performed a forward genetic screen in Caenorhabditis elegans for mutants defective in dense-core vesicle function. We previously reported the identification of two conserved proteins that interact with the small GTPase RAB-2 to control normal dense-core vesicle cargo-sorting. Here we identify several additional conserved factors important for dense-core vesicle cargo sorting: the WD40 domain protein EIPR-1 and the endosome-associated recycling protein (EARP complex. By assaying behavior and the trafficking of dense-core vesicle cargos, we show that mutants that lack EIPR-1 or EARP have defects in dense-core vesicle cargo-sorting similar to those of mutants in the RAB-2 pathway. Genetic epistasis data indicate that RAB-2, EIPR-1 and EARP function in a common pathway. In addition, using a proteomic approach in rat insulinoma cells, we show that EIPR-1 physically interacts with the EARP complex. Our data suggest that EIPR-1 is a new interactor of the EARP complex and that dense-core vesicle cargo sorting depends on the EARP-dependent trafficking of cargo through an endosomal sorting compartment.

Particle Transport and Size Sorting in Bubble Microstreaming Flow

Science.gov (United States)

Thameem, Raqeeb; Rallabandi, Bhargav; Wang, Cheng; Hilgenfeldt, Sascha

2014-11-01

Ultrasonic driving of sessile semicylindrical bubbles results in powerful steady streaming flows that are robust over a wide range of driving frequencies. In a microchannel, this flow field pattern can be fine-tuned to achieve size-sensitive sorting and trapping of particles at scales much smaller than the bubble itself; the sorting mechanism has been successfully described based on simple geometrical considerations. We investigate the sorting process in more detail, both experimentally (using new parameter variations that allow greater control over the sorting) and theoretically (incorporating the device geometry as well as the superimposed channel flow into an asymptotic theory). This results in optimized criteria for size sorting and a theoretical description that closely matches the particle behavior close to the bubble, the crucial region for size sorting.

Dynamic analysis of magnetic nanoparticles crossing cell membrane

Energy Technology Data Exchange (ETDEWEB)

Pedram, Maysam Z. [Department of Mechanical Engineering, Sharif University of Tech., Azadi Ave., Tehran (Iran, Islamic Republic of); Shamloo, Amir, E-mail: shamloo@sharif.edu [Department of Mechanical Engineering, Sharif University of Tech., Azadi Ave., Tehran (Iran, Islamic Republic of); Ghafar-Zadeh, Ebrahim [Biologically-Inspired Sensors and Actuators Laboratory, Department of Electrical Engineering and Computer science, York University, Keel Street, Toronto (Canada); Alasty, Aria, E-mail: aalasti@sharif.edu [Department of Mechanical Engineering, Sharif University of Tech., Azadi Ave., Tehran (Iran, Islamic Republic of)

2017-05-01

Nowadays, nanoparticles (NPs) are used in a variety of biomedical applications including brain disease diagnostics and subsequent treatments. Among the various types of NPs, magnetic nanoparticles (MNPs) have been implemented by many research groups for an array of life science applications. In this paper, we studied MNPs controlled delivery into the endothelial cells using a magnetic field. Dynamics equations of MNPs were defined in the continuous domain using control theory methods and were applied to crossing the cell membrane. This study, dedicated to clinical and biomedical research applications, offers a guideline for the generation of a magnetic field required for the delivery of MNPs.

Proliferation and chondrogenic differentiation of CD105-positive enriched rat synovium-derived mesenchymal stem cells in three-dimensional porous scaffolds

Energy Technology Data Exchange (ETDEWEB)

Qi Jun; Chen Anmin; You Hongbo; Li Kunpeng; Zhang Di; Guo Fengjing, E-mail: fjguo@tjh.tjmu.edu.cn [Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China)

2011-02-15

Stem cell-based tissue engineering has provided an alternative strategy to treat cartilage lesions, and synovium-derived mesenchymal stem cells (SMSCs) are considered as a promising cell source for cartilage repair. In this study, the SMSCs were isolated from rat synovium, and CD105-positive (CD105{sup +}) cells were enriched using magnetic activated cell sorting. Sorted cells were subsequently seeded onto the chitosan-alginate composite three-dimensional (3D) porous scaffolds and cultured in chondrogenic culture medium in the presence of TGF-{beta}{sub 3} and BMP-2 for 2 weeks in vitro. After 2 weeks in culture, scanning electron microscopy results showed that cells attached and proliferated well on scaffolds, and secreted extracellular matrix were also observed. From day 7 to day 14, the total DNA and glucosaminoglycan content of the cells cultured in scaffolds were found to have increased significantly, and cell cycle analyses revealed that the percentage of cells in the S and G2/M phases increased and the percentage of cells in the G0/G1 phase decreased. Compared with non-sorted cells, the sorted cells cultured in scaffolds underwent more chondrogenic differentiation, as evidenced by higher expression of type II collagen and Sox9 at the protein and mRNA levels. The results suggest that CD105{sup +} enriched SMSCs may be a potential cell source for cartilage tissue engineering, and the chitosan-alginate composite 3D porous scaffold could provide a favorable microenvironment for supporting proliferation and chondrogenic differentiation of cells.

The Q sort theory and technique.

Science.gov (United States)

Nyatanga, L

1989-10-01

This paper is based on the author's experience of using the Q sort technique with BA Social Sciences (BASS) students, and the community psychiatric nursing (CPN, ENB No 811 course). The paper focuses on two main issues: 1. The theoretical assumptions underpinning the Q Sort technique. Carl Rogers' self theory and some of the values of humanistic psychology are summarised. 2. The actual technique procedure and meaning of results are highlighted. As the Q Sort technique is potentially useful in a variety of sittings some of which are listed in this paper, the emphasis has deliberately been placed in understanding the theoretical underpinning and the operationalisation (sensitive interpretation) of the theory to practice.

[Regulatory T cells inhibit proliferation of mouse lymphoma cell line EL4 in vitro].

Science.gov (United States)

Zhang, Chen; Kong, Yan; Guo, Jun; Ying, Zhi-Tao; Yuan, Zhi-Hong; Zhang, Yun-Tao; Zheng, Wen; Song, Yu-Qin; Li, Ping-Ping; Zhu, Jun

2010-10-01

This study was aimed to investigate the effect of regulatory T (Treg) cells on the T cell lymphoma EL4 cells and its mechanism in vitro. C57BL/6 mouse Treg cells were isolated by magnetic cell sorting (MACS). The purity of Treg cells and their expression of Foxp3 were identified by flow cytometry (FCM) and PT-PCR respectively. The suppression of Treg cells on EL4 cells was detected by 3H-TdR method. At the same time, enzyme-linked immunosorbent assay (ELISA) was used to detect the secretion of cytokine TGF-β1 and IL-10. The results showed that CD4+CD25+ T cells could be successfully isolated by MACS with the purity reaching 94.52% and the expression of Foxp3 reaching 84.72%. After sorting, the expression of Foxp3 mRNA could be detected by RT-PCR. 3H-TdR assay confirmed that regulatory T cells could suppress the proliferation of EL4 cells with or without antigen presenting cells (APC) or dendritic cells (DC), APC or DC might effectively enhance the suppression. In addition, DC alone also suppressed the proliferation. TGF-β1 and IL-10 could be detected in the supernatant by ELISA. It is concluded that the Treg cells can obviously suppress the proliferation of T cell lymphoma cells in vitro, APC or DC can enhance this suppressive effect, while the DC alone also can suppress the proliferation of EL4 cells, the TGF-β1 and IL-10 cytokine pathway may be one of the mechanisms of suppression.

Event shape sorting

International Nuclear Information System (INIS)

Kopecna, Renata; Tomasik, Boris

2016-01-01

We propose a novel method for sorting events of multiparticle production according to the azimuthal anisotropy of their momentum distribution. Although the method is quite general, we advocate its use in analysis of ultra-relativistic heavy-ion collisions where a large number of hadrons is produced. The advantage of our method is that it can automatically sort out samples of events with histograms that indicate similar distributions of hadrons. It takes into account the whole measured histograms with all orders of anisotropy instead of a specific observable (e.g., v 2 , v 3 , q 2 ). It can be used for more exclusive experimental studies of flow anisotropies which are then more easily compared to theoretical calculations. It may also be useful in the construction of mixed-events background for correlation studies as it allows to select events with similar momentum distribution. (orig.)

Instant magnetic labeling of tumor cells by ultrasound in vitro

International Nuclear Information System (INIS)

Mo Runyang; Yang Jian; Wu, Ed X.; Lin Shuyu

2011-01-01

Magnetic labeling of living cells creates opportunities for numerous biomedical applications. Here we describe an instantly cell magnetic labeling method based on ultrasound. We present a detailed study on the ultrasound performance of a simple and efficient labeling protocol for H-22 cells in vitro. High frequency focus ultrasound was investigated as an alternative method to achieve instant cell labeling with the magnetic particles without the need for adjunct agents or initiating cell cultures. Mean diameter of 168 nm dextran-T40 coated superparamagnetic iron oxide (SPIO) nanoparticles were prepared by means of classical coprecipitation in solution in our laboratory. H-22 tumor cells suspended in phosphate-buffered saline (PBS, pH=7.2) were exposed to ultrasound at 1.37 MHz for up to 120 s in the presence of SPIOs. The cellular uptake of iron oxide nanoparticles was detected by prussion blue staining. The viability of cells was determined by a trypan blue exclusion test. At 2 W power and 60 s ultrasound exposure in presence of 410 μg/ml SPIOs, H-22 cell labeling efficiency reached 69.4±6.3% and the labeled cells exhibited an iron content of 10.38±2.43 pg per cell. Furthermore, 95.2±3.2% cells remained viable. The results indicated that the ultrasound protocol could be potentially applied to label cells with large-sized magnetic particles. We also calculated the shear stress at the 2 W power and 1.37 MHz used in experiments. The results showed that the shear stress threshold for ultrasonically induced H-22 cell reparable sonoporation was 697 Pa. These findings provide a quantitative guidance in designing ultrasound protocols for cell labeling. - Highlights: → High frequency focus ultrasound can be used as a safe method for instant magnetic labeling of cells. → 8-16 times increased efficiency can be gained by ultrasound versus that by transfection agents. → Calculation of shear stress around cells provide a quantitative design for ultrasound protocols.

Development of sorting system control using LABVIEW

International Nuclear Information System (INIS)

Azraf Azman; Mohd Arif Hamzah; Noriah Mod Ali; John Konsoh; Mohd Idris Taib; Maslina Mohd Ibrahim; Nor Arymaswati Abdullah; Abu Bakar Mhd Ghazali

2005-01-01

The development of the Personnel Dosimeter Sorting System, proposed by the Secondary Standard Dosimetry Laboratory (SSDL) is to enhance the system or work flow in preparing the personnel dosimeter. The main objective of the system is to reduce stamping error, time and cost. The Personnel Dosimeter Sorting System is a semi-automatic system with an interfacing method using the Advantec 32 bit PCI interface card of 64 digital input and output. The system is integrated with the Labview version 7.1 programming language to control the sorting system and operation. (Author)

An effective strategy of magnetic stem cell delivery for spinal cord injury therapy

Science.gov (United States)

Tukmachev, Dmitry; Lunov, Oleg; Zablotskii, Vitalii; Dejneka, Alexandr; Babic, Michal; Syková, Eva; Kubinová, Šárka

2015-02-01

Spinal cord injury (SCI) is a condition that results in significant mortality and morbidity. Treatment of SCI utilizing stem cell transplantation represents a promising therapy. However, current conventional treatments are limited by inefficient delivery strategies of cells into the injured tissue. In this study, we designed a magnetic system and used it to accumulate stem cells labelled with superparamagnetic iron oxide nanoparticles (SPION) at a specific site of a SCI lesion. The loading of stem cells with engineered SPIONs that guarantees sufficient attractive magnetic forces was achieved. Further, the magnetic system allowed rapid guidance of the SPION-labelled cells precisely to the lesion location. Histological analysis of cell distribution throughout the cerebrospinal channel showed a good correlation with the calculated distribution of magnetic forces exerted onto the transplanted cells. The results suggest that focused targeting and fast delivery of stem cells can be achieved using the proposed non-invasive magnetic system. With future implementation the proposed targeting and delivery strategy bears advantages for the treatment of disease requiring fast stem cell transplantation.Spinal cord injury (SCI) is a condition that results in significant mortality and morbidity. Treatment of SCI utilizing stem cell transplantation represents a promising therapy. However, current conventional treatments are limited by inefficient delivery strategies of cells into the injured tissue. In this study, we designed a magnetic system and used it to accumulate stem cells labelled with superparamagnetic iron oxide nanoparticles (SPION) at a specific site of a SCI lesion. The loading of stem cells with engineered SPIONs that guarantees sufficient attractive magnetic forces was achieved. Further, the magnetic system allowed rapid guidance of the SPION-labelled cells precisely to the lesion location. Histological analysis of cell distribution throughout the cerebrospinal

Effects of high-gradient magnetic fields on living cell machinery

Czech Academy of Sciences Publication Activity Database

Zablotskyy, Vitaliy A.; Lunov, Oleg; Kubinová, Šárka; Polyakova, Tetyana; Syková, E.; Dejneka, Alexandr

2016-01-01

Roč. 49, č. 49 (2016), s. 1-23, č. článku 493003. ISSN 0022-3727 R&D Projects: GA MŠk LO1409 Grant - others:FUNBIO(XE) CZ.2.16/3.1.00/21568 Institutional support: RVO:68378271 Keywords : living cell * magnetic gradient force * cell mechanics * stem cell * magnetic field Subject RIV: BO - Biophysics Impact factor: 2.588, year: 2016

Sorting and selection in posets

DEFF Research Database (Denmark)

Daskalakis, Constantinos; Karp, Richard M.; Mossel, Elchanan

2011-01-01

from two decades ago by Faigle and Turán. In particular, we present the first algorithm that sorts a width-$w$ poset of size $n$ with query complexity $O(n(w+\\log n))$ and prove that this query complexity is asymptotically optimal. We also describe a variant of Mergesort with query complexity $O......(wn\\log\\frac{n}{w})$ and total complexity $O(w^{2}n\\log\\frac{n}{w})$; an algorithm with the same query complexity was given by Faigle and Turán, but no efficient implementation of that algorithm is known. Both our sorting algorithms can be applied with negligible overhead to the more general problem of reconstructing transitive......Classical problems of sorting and searching assume an underlying linear ordering of the objects being compared. In this paper, we study these problems in the context of partially ordered sets, in which some pairs of objects are incomparable. This generalization is interesting from a combinatorial...

Addressing of LnCaP Cell Using Magnetic Particles Assisted Impedimetric Microelectrode.

Science.gov (United States)

Nguyen, Dung Thi Xuan; Tran, Trong Binh; Nguyen, Phuong-Diem; Min, Junhong

2016-03-01

In this study, we provide a facile, effective technique for a simple isolation and enrichment of low metastatic prostate tumor cell LNCaP using biocompatible, magnetic particles asissted impedimetric sensing system. Hydrophobic cell membrane anchors (BAM) were generated onto magnetic particles which diameters vary from 50 nm to 5 μm and were used to capture LNCaP cells from the suspension. Finally, magnetic particle-LNCaP complex were addressed onto the surface of the interdigitated microelectrode (IDM). Cell viability was monitored by our laboratory developed-technique Electrical Cell Substrate Impedance Sensing (ECIS). The results reavealed that 50 nm-magnetic particles showed best performance in terms of cell separation and cell viability. This technique provides a simple and efficient method for the direct addressing of LNCaP cell on the surface and enhances better understanding of cell behavior for cancer management in the near future.

Magnetization of large polystyrene peptide beads for capturing and expanding cancer cells

International Nuclear Information System (INIS)

Marik, Jan; Lau, D.H.; Song Aimin; Wang Xiaobing; Liu Ruiwu; Lam, K.S.

2003-01-01

A method is described for preparation of large magnetic polystyrene beads coupled with peptide ligands for surface receptors of lung cancer cells. We have demonstrated the feasibility of using these magnetic peptide beads for capturing and enriching lung cancer cells spiked into blood. These magnetic peptide beads potentially can be used to efficiently isolate cancer cells from body fluids

Aptamer-based isolation and subsequent imaging of mesenchymal stem cells in ischemic myocard by magnetic resonance imaging.

Science.gov (United States)

Schäfer, R; Wiskirchen, J; Guo, K; Neumann, B; Kehlbach, R; Pintaske, J; Voth, V; Walker, T; Scheule, A M; Greiner, T O; Hermanutz-Klein, U; Claussen, C D; Northoff, H; Ziemer, G; Wendel, H P

2007-10-01

Mesenchymal stem cells (MSC) seem to be a promising cell source for cellular cardiomyoplasty. We recently developed a new aptamer-based specific selection of MSC to provide "ready to transplant" cells directly after isolation. We evaluated MRI tracking of newly isolated and freshly transplanted MSC in the heart using one short ex vivo selection step combining specific aptamer-based isolation and labeling of the cells. Bone marrow (BM) was collected from healthy pigs. The animals were euthanized and the heart was placed in a perfusion model. During cold ischemia, immunomagnetic isolation of MSC from the BM by MSC-specific aptamers labeled with Dynabeads was performed within 2 h. For histological identification the cells were additionally stained with PKH26. Approx. 3 x 10(6) of the freshly aptamer-isolated cells were injected into the ramus interventricularis anterior (RIVA) and 5 x 10(5) cells were injected directly into myocardial tissue after damaging the respective area by freezing (cryo-scar). 3 x 10(6) of the aptamer-isolated cells were kept for further characterization (FACS and differentiation assays). 20 h after cell transplantation, MRI of the heart using a clinical 3.0 Tesla whole body scanner (Magnetom Trio, Siemens, Germany) was performed followed by histological examinations. The average yield of sorted cells from 120 ml BM was 7 x 10(6) cells. The cells were cultured and showed MSC-like properties. MRI showed reproducible artifacts within the RIVA-perfusion area and the cryo-scar with surprisingly excellent quality. The histological examination of the biopsies showed PKH26-positive cells within the areas which were positive in the MRI in contrast to the control biopsies. Immunomagnetic separation of MSC by specific aptamers linked to magnetic particles is feasible, effective and combines a specific separation and labeling technique to a "one stop shop" strategy.

Magnetic Studies of Ferrofluid-Modified Microbial Cells

Czech Academy of Sciences Publication Activity Database

Mosiniewicz-Szablewska, E.; Šafaříková, Miroslava; Šafařík, Ivo

2010-01-01

Roč. 10, č. 4 (2010), s. 2531-2536 ISSN 1533-4880 R&D Projects: GA MPO(CZ) 2A-1TP1/094; GA MŠk(CZ) OC 108 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetically labeled cells * biocomposite materials * magnetic adsorbents Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.351, year: 2010

Consensus-Based Sorting of Neuronal Spike Waveforms.

Science.gov (United States)

Fournier, Julien; Mueller, Christian M; Shein-Idelson, Mark; Hemberger, Mike; Laurent, Gilles

2016-01-01

Optimizing spike-sorting algorithms is difficult because sorted clusters can rarely be checked against independently obtained "ground truth" data. In most spike-sorting algorithms in use today, the optimality of a clustering solution is assessed relative to some assumption on the distribution of the spike shapes associated with a particular single unit (e.g., Gaussianity) and by visual inspection of the clustering solution followed by manual validation. When the spatiotemporal waveforms of spikes from different cells overlap, the decision as to whether two spikes should be assigned to the same source can be quite subjective, if it is not based on reliable quantitative measures. We propose a new approach, whereby spike clusters are identified from the most consensual partition across an ensemble of clustering solutions. Using the variability of the clustering solutions across successive iterations of the same clustering algorithm (template matching based on K-means clusters), we estimate the probability of spikes being clustered together and identify groups of spikes that are not statistically distinguishable from one another. Thus, we identify spikes that are most likely to be clustered together and therefore correspond to consistent spike clusters. This method has the potential advantage that it does not rely on any model of the spike shapes. It also provides estimates of the proportion of misclassified spikes for each of the identified clusters. We tested our algorithm on several datasets for which there exists a ground truth (simultaneous intracellular data), and show that it performs close to the optimum reached by a support vector machine trained on the ground truth. We also show that the estimated rate of misclassification matches the proportion of misclassified spikes measured from the ground truth data.

Magnetic catechin-dextran conjugate as targeted therapeutic for pancreatic tumour cells.

Science.gov (United States)

Vittorio, Orazio; Voliani, Valerio; Faraci, Paolo; Karmakar, Biswajit; Iemma, Francesca; Hampel, Silke; Kavallaris, Maria; Cirillo, Giuseppe

2014-06-01

Catechin-dextran conjugates have recently attracted a lot of attention due to their anticancer activity against a range of cancer cells. Magnetic nanoparticles have the ability to concentrate therapeutically important drugs due to their magnetic-spatial control and provide opportunities for targeted drug delivery. Enhancement of the anticancer efficiency of catechin-dextran conjugate by functionalisation with magnetic iron oxide nanoparticles. Modification of the coating shell of commercial magnetic nanoparticles (Endorem) composed of dextran with the catechin-dextran conjugate. Catechin-dextran conjugated with Endorem (Endo-Cat) increased the intracellular concentration of the drug and it induced apoptosis in 98% of pancreatic tumour cells placed under magnetic field. The conjugation of catechin-dextran with Endorem enhances the anticancer activity of this drug and provides a new strategy for targeted drug delivery on tumour cells driven by magnetic field. The ability to spatially control the delivery of the catechin-dextran by magnetic field makes it a promising agent for further application in cancer therapy.

MODELING WORK OF SORTING STATION USING UML

Directory of Open Access Journals (Sweden)

O. V. Gorbova

2014-12-01

Full Text Available Purpose. The purpose of this paper is the construction of methods and models for the graphical representation process of sorting station, using the unified modeling language (UML. Methodology. Methods of graph theory, finite automata and the representation theory of queuing systems were used as the methods of investigation. A graphical representation of the process was implemented with using the Unified Modeling Language UML. The sorting station process representation is implemented as a state diagram and actions through a set of IBM Rational Rose. Graphs can show parallel operation of sorting station, the parallel existence and influence of objects process and the transition from one state to another. The IBM Rational Rose complex allows developing a diagram of work sequence of varying degrees of detailing. Findings. The study has developed a graphical representation method of the process of sorting station of different kind of complexity. All graphical representations are made using the UML. They are represented as a directed graph with the states. It is clear enough in the study of the subject area. Applying the methodology of the representation process, it allows becoming friendly with the work of any automation object very fast, and exploring the process during algorithms construction of sorting stations and other railway facilities. This model is implemented with using the Unified Modeling Language (UML using a combination of IBM Rational Rose. Originality. The representation process of sorting station was developed by means of the Unified Modeling Language (UML use. Methodology of representation process allows creating the directed graphs based on the order of execution of the works chain, objects and performers of these works. The UML allows visualizing, specifying, constructing and documenting, formalizing the representation process of sorting station and developing sequence diagrams of works of varying degrees of detail. Practical

Synthesis of magnetic microtubes decorated with nanowires and cells

Science.gov (United States)

Pomar, C. Diaz; Martinho, H.; Ferreira, F. F.; Goia, T. S.; Rodas, A. C. D.; Santos, S. F.; Souza, J. A.

2018-04-01

Antiferromagnetic and ferrimagnetic microtubes decorated with nanowires have been obtained during thermal oxidation process, which was assisted by in situ electrical resistivity measurements. The synthesis route including heat treatment and electrical current along with growth mechanism are presented. This simple method and the ability to tune in the magnetic moment of the obtained microtubes going from a nonmagnetic-like to a large magnetization saturation open an avenue for interesting applications. In vitro experiments involving adherence, migration, and proliferation of fibroblasts cell culture on the surface of the microtubes indicated the absence of cytotoxicity for this material. We have also calculated both torque and driving magnetic force for these microtubes with nanowires and cells as a function of external magnetic field gradient which were found to be robust opening the possibility for magnetic bio micro-robot device fabrication and application in biotechnology.

Passive sorting of capsules by deformability

Science.gov (United States)

Haener, Edgar; Juel, Anne

We study passive sorting according to deformability of liquid-filled ovalbumin-alginate capsules. We present results for two sorting geometries: a straight channel with a half-cylindrical obstruction and a pinched flow fractioning device (PFF) adapted for use with capsules. In the half-cylinder device, the capsules deform as they encounter the obstruction, and travel around the half-cylinder. The distance from the capsule's centre of mass to the surface of the half-cylinder depends on deformability, and separation between capsules of different deformability is amplified by diverging streamlines in the channel expansion downstream of the obstruction. We show experimentally that capsules can be sorted according to deformability with their downstream position depending on capillary number only, and we establish the sensitivity of the device to experimental variability. In the PFF device, particles are compressed against a wall using a strong pinching flow. We show that capsule deformation increases with the intensity of the pinching flow, but that the downstream capsule position is not set by deformation in the device. However, when using the PFF device like a T-Junction, we achieve improved sorting resolution compared to the half-cylinder device.

The interaction between Sertoli cells and luekemia inhibitory factor on the propagation and differentiation of spermatogonial stem cells in vitro.

Science.gov (United States)

Rastegar, Tayebeh; Habibi Roudkenar, Mehryar; Parvari, Soraya; Baazm, Maryam

2015-11-01

Sertoli cells play a pivotal role in creating microenvironments essential for spermatogonial stem cells (SSCs) self-renewal and commitment to differentiation. Maintenance of SSCs and or induction of in vitro spermiogenesis may provide a therapeutic strategy to treat male infertility. This study investigated the role of luekemia inhibitory factor (LIF) on the propagation of SSCs and both functions of Sertoli cells on the proliferation and differentiation of these cells. SSCs were sorted from the testes of adult male mice by magnetic activated cell sorting and thymus cell antigen 1 antibody. On the other hand, isolated Sertoli cells were enriched using lectin coated plates. SSCs were cultured on Sertoli cells for 7 days in the absence or presence of LIF. The effects of these conditions were evaluated by microscopy and expression of meiotic and post meiotic transcripts by reverse transcriptase polymerase chain reaction. Our data showed that SSCs co-cultured with Sertoli cells in the presence of LIF formed colonies on top of the Sertoli cells. These colonies had alkaline phosphatesase activity and expressed SSCs specific genes. SSCs were enjoyed limited development after the mere removal of LIF, and exhibiting expression of meiotic and postmeiotic transcript and loss of SSCs specific gene expression (p< 0.05). Our findings represent co-culture of SSCs with Sertoli cells provides conditions that may allow efficient proliferation and differentiation of SSCs for male infertility treatment.

On Sorting Genomes with DCJ and Indels

Science.gov (United States)

Braga, Marília D. V.

A previous work of Braga, Willing and Stoye compared two genomes with unequal content, but without duplications, and presented a new linear time algorithm to compute the genomic distance, considering double cut and join (DCJ) operations, insertions and deletions. Here we derive from this approach an algorithm to sort one genome into another one also using DCJ, insertions and deletions. The optimal sorting scenarios can have different compositions and we compare two types of sorting scenarios: one that maximizes and one that minimizes the number of DCJ operations with respect to the number of insertions and deletions.

Pulsed taut-wire measurement of the magnetic alignment of the ITS induction cells

International Nuclear Information System (INIS)

Melton, J.G.; Burns, M.J.; Honaberger, D.J.

1993-01-01

The mechanical and magnetic alignment of the first eight induction-cell, solenoid magnets of the Integrated Test Stand (ITS) for the Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility were measured by observing the deflection of a fine, taut wire carrying a pulsed current. To achieve the required alignment (less than 0.25 mm offset and less than 5 mrad tilt), the magnet design uses quadrufilar windings and iron field-smoothing rings. After detailed measurements of each solenoid magnet, the cells are assembled and then mechanically aligned using a laser and an alignment target moved along the cell centerline. After the cells are in final position, the pulsed wire method is used to verify the magnetic alignment. The measurements show an average offset of the magnetic axes from the mechanical axis of 0. 15 mm, with a maximum offset of 0.3 mm. The average tilt of the magnetic axis was 0.7 mrad with a maximum tilt of 1.4 mrad. Tilts are corrected to less than 0.3 mrad, using dipole trim magnets assembled into each cell. Correction is limited noise

Disruptive effect of Dzyaloshinskii-Moriya interaction on the magnetic memory cell performance

Energy Technology Data Exchange (ETDEWEB)

Sampaio, J.; Cubukcu, M.; Cros, V.; Reyren, N., E-mail: nicolas.reyren@thalesgroup.com [Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau (France); Khvalkovskiy, A. V. [Samsung Electronics, Semiconductor R& D Center (Grandis), San Jose, California 95134 (United States); Moscow Institute of Physics and Technology, State University, Moscow 141700 (Russian Federation); Kuteifan, M.; Lomakin, V. [Department of Electrical and Computer Engineering, University of California at San Diego, La Jolla, California 92093-0407 (United States); Apalkov, D. [Samsung Electronics, Semiconductor R& D Center (Grandis), San Jose, California 95134 (United States)

2016-03-14

In order to increase the thermal stability of a magnetic random access memory cell, materials with high spin-orbit interaction are often introduced in the storage layer. As a side effect, a strong Dzyaloshinskii-Moriya interaction (DMI) may arise in such systems. Here, we investigate the impact of DMI on the magnetic cell performance, using micromagnetic simulations. We find that DMI strongly promotes non-uniform magnetization states and non-uniform switching modes of the magnetic layer. It appears to be detrimental for both the thermal stability of the cell and its switching current, leading to considerable deterioration of the cell performance even for a moderate DMI amplitude.

Algorithm 426 : Merge sort algorithm [M1

NARCIS (Netherlands)

Bron, C.

1972-01-01

Sorting by means of a two-way merge has a reputation of requiring a clerically complicated and cumbersome program. This ALGOL 60 procedure demonstrates that, using recursion, an elegant and efficient algorithm can be designed, the correctness of which is easily proved [2]. Sorting n objects gives

A many-sorted calculus based on resolution and paramodulation

CERN Document Server

Walther, Christoph

1987-01-01

A Many-Sorted Calculus Based on Resolution and Paramodulation emphasizes the utilization of advantages and concepts of many-sorted logic for resolution and paramodulation based automated theorem proving.This book considers some first-order calculus that defines how theorems from given hypotheses by pure syntactic reasoning are obtained, shifting all the semantic and implicit argumentation to the syntactic and explicit level of formal first-order reasoning. This text discusses the efficiency of many-sorted reasoning, formal preliminaries for the RP- and ?RP-calculus, and many-sorted term rewrit

Clinically viable magnetic poly(lactide-co-glycolide) (PLGA) particles for MRI-based cell tracking

Science.gov (United States)

Granot, Dorit; Nkansah, Michael K.; Bennewitz, Margaret F.; Tang, Kevin S.; Markakis, Eleni A.; Shapiro, Erik M.

2013-01-01

Purpose To design, fabricate, characterize and in vivo assay clinically viable magnetic particles for MRI-based cell tracking. Methods PLGA encapsulated magnetic nano- and microparticles were fabricated. Multiple biologically relevant experiments were performed to assess cell viability, cellular performance and stem cell differentiation. In vivo MRI experiments were performed to separately test cell transplantation and cell migration paradigms, as well as in vivo biodegradation. Results Highly magnetic nano- (~100 nm) and microparticles (~1–2 μm) were fabricated. Magnetic cell labeling in culture occurred rapidly achieving 3–50 pg Fe/cell at 3 hrs for different particles types, and >100 pg Fe/cell after 10 hours, without the requirement of a transfection agent, and with no effect on cell viability. The capability of magnetically labeled mesenchymal or neural stem cells to differentiate down multiple lineages, or for magnetically labeled immune cells to release cytokines following stimulation, was uncompromised. An in vivo biodegradation study revealed that NPs degraded ~80% over the course of 12 weeks. MRI detected as few as 10 magnetically labeled cells, transplanted into the brains of rats. Also, these particles enabled the in vivo monitoring of endogenous neural progenitor cell migration in rat brains over 2 weeks. Conclusion The robust MRI properties and benign safety profile of these particles make them promising candidates for clinical translation for MRI-based cell tracking. PMID:23568825

An empirical study on SAJQ (Sorting Algorithm for Join Queries

Directory of Open Access Journals (Sweden)

Hassan I. Mathkour

2010-06-01

Full Text Available Most queries that applied on database management systems (DBMS depend heavily on the performance of the used sorting algorithm. In addition to have an efficient sorting algorithm, as a primary feature, stability of such algorithms is a major feature that is needed in performing DBMS queries. In this paper, we study a new Sorting Algorithm for Join Queries (SAJQ that has both advantages of being efficient and stable. The proposed algorithm takes the advantage of using the m-way-merge algorithm in enhancing its time complexity. SAJQ performs the sorting operation in a time complexity of O(nlogm, where n is the length of the input array and m is number of sub-arrays used in sorting. An unsorted input array of length n is arranged into m sorted sub-arrays. The m-way-merge algorithm merges the sorted m sub-arrays into the final output sorted array. The proposed algorithm keeps the stability of the keys intact. An analytical proof has been conducted to prove that, in the worst case, the proposed algorithm has a complexity of O(nlogm. Also, a set of experiments has been performed to investigate the performance of the proposed algorithm. The experimental results have shown that the proposed algorithm outperforms other Stable–Sorting algorithms that are designed for join-based queries.

Detecting molecules and cells labeled with magnetic particles using an atomic magnetometer

International Nuclear Information System (INIS)

Yu Dindi; Ruangchaithaweesuk, Songtham; Yao Li; Xu Shoujun

2012-01-01

The detection of magnetically labeled molecules and cells involves three essential parameters: sensitivity, spatial resolution, and molecular specificity. We report on the use of atomic magnetometry and its derivative techniques to achieve high performance in terms of all these parameters. With a sensitivity of 80 fT/√Hz for dc magnetic fields, we show that 7,000 streptavidin-conjugated magnetic microparticles magnetized by a permanent magnet produce a magnetic field of 650 pT; this result predicts that a single such particle can be detected during one second of signal averaging. Spatial information is obtained using a scanning magnetic imaging scheme. The spatial resolution is 20 μm with a detection distance of more than 1 cm; this distance is much longer than that in previous reports. The molecular specificity is achieved using force-induced remnant magnetization spectroscopy, which currently uses an atomic magnetometer for detection. As an example, we perform measurement of magnetically labeled human CD4+ T cells, whose count in the blood is the diagnostic criterion for human immunodeficiency virus infection. Magnetic particles that are specifically bound to the cells are resolved from nonspecifically bound particles and quantitatively correlate with the number of cells. The magnetic particles have an overall size of 2.8 μm, with a magnetic core in nanometer regime. The combination of our techniques is predicted to be useful in molecular and cellular imaging.

Detecting molecules and cells labeled with magnetic particles using an atomic magnetometer

Energy Technology Data Exchange (ETDEWEB)

Yu Dindi; Ruangchaithaweesuk, Songtham; Yao Li; Xu Shoujun, E-mail: sxu7@uh.edu [University of Houston, Department of Chemistry (United States)

2012-09-15

The detection of magnetically labeled molecules and cells involves three essential parameters: sensitivity, spatial resolution, and molecular specificity. We report on the use of atomic magnetometry and its derivative techniques to achieve high performance in terms of all these parameters. With a sensitivity of 80 fT/{radical}Hz for dc magnetic fields, we show that 7,000 streptavidin-conjugated magnetic microparticles magnetized by a permanent magnet produce a magnetic field of 650 pT; this result predicts that a single such particle can be detected during one second of signal averaging. Spatial information is obtained using a scanning magnetic imaging scheme. The spatial resolution is 20 {mu}m with a detection distance of more than 1 cm; this distance is much longer than that in previous reports. The molecular specificity is achieved using force-induced remnant magnetization spectroscopy, which currently uses an atomic magnetometer for detection. As an example, we perform measurement of magnetically labeled human CD4+ T cells, whose count in the blood is the diagnostic criterion for human immunodeficiency virus infection. Magnetic particles that are specifically bound to the cells are resolved from nonspecifically bound particles and quantitatively correlate with the number of cells. The magnetic particles have an overall size of 2.8 {mu}m, with a magnetic core in nanometer regime. The combination of our techniques is predicted to be useful in molecular and cellular imaging.

Science and technology of kernels and TRISO coated particle sorting

International Nuclear Information System (INIS)

Nothnagel, G.

2006-09-01

The ~1mm diameter TRISO coated particles, which form the elemental units of PBMR nuclear fuel, has to be close to spherical in order to best survive damage during sphere pressing. Spherical silicon carbide layers further provide the strongest miniature pressure vessels for fission product retention. To make sure that the final product contains particles of acceptable shape, 100% of kernels and coated particles have to be sorted on a surface-ground sorting table. Broken particles, twins, irregular (odd) shapes and extreme ellipsoids have to be separated from the final kernel and coated particle batches. Proper sorting of particles is an extremely important step in quality fuel production as the final failure fraction depends sensitively on the quality of sorting. After sorting a statistically significant sample of the sorted product is analysed for sphericity, which is defined as the ratio of maximum to minimum diameter, as part of a standard QC test to ensure conformance to German specifications. In addition a burn-leach test is done on coated particles (before pressing) and fuel spheres (after pressing) to ensure adherence to failure specifications. Because of the extreme importance of particle sorting for assurance of fuel quality it is essential to have an in-depth understanding of the capabilities and limitations of particle sorting. In this report a systematic scientific rationale is developed, from fundamental principles, to provide a basis for understanding the relationship between product quality and sorting parameters. The principles and concepts, developed in this report, will be of importance when future sorting tables (or equivalents) are to be designed. A number of new concepts and methodologies are developed to assist with equivalence validation of any two sorting tables. This is aimed in particular towards quantitative assessment of equivalence between current QC tables (closely based on the original NUKEM parameters, except for the driving mechanism

The Container Problem in Bubble-Sort Graphs

Science.gov (United States)

Suzuki, Yasuto; Kaneko, Keiichi

Bubble-sort graphs are variants of Cayley graphs. A bubble-sort graph is suitable as a topology for massively parallel systems because of its simple and regular structure. Therefore, in this study, we focus on n-bubble-sort graphs and propose an algorithm to obtain n-1 disjoint paths between two arbitrary nodes in time bounded by a polynomial in n, the degree of the graph plus one. We estimate the time complexity of the algorithm and the sum of the path lengths after proving the correctness of the algorithm. In addition, we report the results of computer experiments evaluating the average performance of the algorithm.

Heuristic framework for parallel sorting computations | Nwanze ...

African Journals Online (AJOL)

Parallel sorting techniques have become of practical interest with the advent of new multiprocessor architectures. The decreasing cost of these processors will probably in the future, make the solutions that are derived thereof to be more appealing. Efficient algorithms for sorting scheme that are encountered in a number of ...

Fruit Sorting Using Fuzzy Logic Techniques

Science.gov (United States)

Elamvazuthi, Irraivan; Sinnadurai, Rajendran; Aftab Ahmed Khan, Mohamed Khan; Vasant, Pandian

2009-08-01

Fruit and vegetables market is getting highly selective, requiring their suppliers to distribute the goods according to very strict standards of quality and presentation. In the last years, a number of fruit sorting and grading systems have appeared to fulfill the needs of the fruit processing industry. However, most of them are overly complex and too costly for the small and medium scale industry (SMIs) in Malaysia. In order to address these shortcomings, a prototype machine was developed by integrating the fruit sorting, labeling and packing processes. To realise the prototype, many design issues were dealt with. Special attention is paid to the electronic weighing sub-system for measuring weight, and the opto-electronic sub-system for determining the height and width of the fruits. Specifically, this paper discusses the application of fuzzy logic techniques in the sorting process.

Erythrocyte enrichment in hematopoietic progenitor cell cultures based on magnetic susceptibility of the hemoglobin.

Directory of Open Access Journals (Sweden)

Xiaoxia Jin

Full Text Available Using novel media formulations, it has been demonstrated that human placenta and umbilical cord blood-derived CD34+ cells can be expanded and differentiated into erythroid cells with high efficiency. However, obtaining mature and functional erythrocytes from the immature cell cultures with high purity and in an efficient manner remains a significant challenge. A distinguishing feature of a reticulocyte and maturing erythrocyte is the increasing concentration of hemoglobin and decreasing cell volume that results in increased cell magnetophoretic mobility (MM when exposed to high magnetic fields and gradients, under anoxic conditions. Taking advantage of these initial observations, we studied a noninvasive (label-free magnetic separation and analysis process to enrich and identify cultured functional erythrocytes. In addition to the magnetic cell separation and cell motion analysis in the magnetic field, the cell cultures were characterized for cell sedimentation rate, cell volume distributions using differential interference microscopy, immunophenotyping (glycophorin A, hemoglobin concentration and shear-induced deformability (elongation index, EI, by ektacytometry to test for mature erythrocyte attributes. A commercial, packed column high-gradient magnetic separator (HGMS was used for magnetic separation. The magnetically enriched fraction comprised 80% of the maturing cells (predominantly reticulocytes that showed near 70% overlap of EI with the reference cord blood-derived RBC and over 50% overlap with the adult donor RBCs. The results demonstrate feasibility of label-free magnetic enrichment of erythrocyte fraction of CD34+ progenitor-derived cultures based on the presence of paramagnetic hemoglobin in the maturing erythrocytes.

Tradeoffs Between Branch Mispredictions and Comparisons for Sorting Algorithms

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Moruz, Gabriel

2005-01-01

Branch mispredictions is an important factor affecting the running time in practice. In this paper we consider tradeoffs between the number of branch mispredictions and the number of comparisons for sorting algorithms in the comparison model. We prove that a sorting algorithm using O(dnlog n......) comparisons performs Omega(nlogd n) branch mispredictions. We show that Multiway MergeSort achieves this tradeoff by adopting a multiway merger with a low number of branch mispredictions. For adaptive sorting algorithms we similarly obtain that an algorithm performing O(dn(1+log (1+Inv/n))) comparisons must...... perform Omega(nlogd (1+Inv/n)) branch mispredictions, where Inv is the number of inversions in the input. This tradeoff can be achieved by GenericSort by Estivill-Castro and Wood by adopting a multiway division protocol and a multiway merging algorithm with a low number of branch mispredictions....

Recent progress in multi-electrode spike sorting methods.

Science.gov (United States)

Lefebvre, Baptiste; Yger, Pierre; Marre, Olivier

2016-11-01

In recent years, arrays of extracellular electrodes have been developed and manufactured to record simultaneously from hundreds of electrodes packed with a high density. These recordings should allow neuroscientists to reconstruct the individual activity of the neurons spiking in the vicinity of these electrodes, with the help of signal processing algorithms. Algorithms need to solve a source separation problem, also known as spike sorting. However, these new devices challenge the classical way to do spike sorting. Here we review different methods that have been developed to sort spikes from these large-scale recordings. We describe the common properties of these algorithms, as well as their main differences. Finally, we outline the issues that remain to be solved by future spike sorting algorithms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acoustic bubble sorting for ultrasound contrast agent enrichment.

Science.gov (United States)

Segers, Tim; Versluis, Michel

2014-05-21

An ultrasound contrast agent (UCA) suspension contains encapsulated microbubbles with a wide size distribution, with radii ranging from 1 to 10 μm. Medical transducers typically operate at a single frequency, therefore only a small selection of bubbles will resonate to the driving ultrasound pulse. Thus, the sensitivity can be improved by narrowing down the size distribution. Here, we present a simple lab-on-a-chip method to sort the population of microbubbles on-chip using a traveling ultrasound wave. First, we explore the physical parameter space of acoustic bubble sorting using well-defined bubble sizes formed in a flow-focusing device, then we demonstrate successful acoustic sorting of a commercial UCA. This novel sorting strategy may lead to an overall improvement of the sensitivity of contrast ultrasound by more than 10 dB.

Rotational magnetic pulses enhance the magnetofection efficiency in vitro in adherent and suspension cells

International Nuclear Information System (INIS)

Dahmani, Ch.; Mykhaylyk, O.; Helling, Fl.; Götz, St.; Weyh, Th.; Herzog, H.-G.; Plank, Ch.

2013-01-01

The association of magnetic nanoparticles with gene delivery vectors in combination with the use of gradient magnetic fields (magnetofection) enables improved and synchronised gene delivery to cells. In this paper, we report a system comprising rotating permanent magnets to generate defined magnetic field pulses with frequencies from 2.66 to 133 Hz and a field amplitude of 190 or 310 mT at the location of the cells. Low-frequency pulses of 2.66–10 Hz with a magnetic flux density of 190 mT were applied to the examined cells for 30–120 s after magnetofection. These pulses resulted in a 1.5–1.9-fold enhancement in the transfection efficiency compared with magnetofection with only a static magnetic field in both adherent and suspension cells. The magnetic field amplitudes of 190 and 310 mT had similar effects on the transfection efficacy. No increase in the percentage of transgene-expressing suspension cells and no cytotoxic effects (based on the results of the MTT assay) were observed after applying alternating magnetic fields. - Highlights: ► We developed a magnetic system capable of generating defined magnetic pulses based on permanent magnets. ► The main advantage of the system is the lack of heat-induced fluctuations in the working parameters. ► Our system succeeded in enhancing the transfection of adherent human lung epithelial cells and human suspension cells. ► The enhancement in the transfection efficiency compared with static magnetic field is due to the magnetic field pulses. ► The approach could be used as a complementary method for drug targeting

Automatic Color Sorting of Hardwood Edge-Glued Panel Parts

Science.gov (United States)

D. Earl Kline; Richard Conners; Qiang Lu; Philip A. Araman

1997-01-01

This paper describes an automatic color sorting system for red oak edge-glued panel parts. The color sorting system simultaneously examines both faces of a panel part and then determines which face has the "best" color, and sorts the part into one of a number of color classes at plant production speeds. Initial test results show that the system generated over...

Automorphism group of the modified bubble-sort graph

OpenAIRE

Ganesan, Ashwin

2014-01-01

The modified bubble-sort graph of dimension $n$ is the Cayley graph of $S_n$ generated by $n$ cyclically adjacent transpositions. In the present paper, it is shown that the automorphism group of the modified bubble sort graph of dimension $n$ is $S_n \\times D_{2n}$, for all $n \\ge 5$. Thus, a complete structural description of the automorphism group of the modified bubble-sort graph is obtained. A similar direct product decomposition is seen to hold for arbitrary normal Cayley graphs generate...

Sorption of strontium by magnetically modified yeast cells

International Nuclear Information System (INIS)

Hu Yantao; Ji Yanqin; Tian Qing; Shao Xianzhang; Shi Jianhe; Ivo Safarik; Zhang Shengdong; Li Jinying

2008-01-01

Magnetically modified fodder's yeast (Kluyveromyces fragilis) cells using water based magnetic fluid, were characterized by scanning electron microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The sorption-desorption properties of Sr 2+ by these yeast cells from nitrate salt of Sr 2+ were studied. The results demonstrated that the Sr 2+ sorption volume by these cells enhanced with increasing pH and reached a plateau between pH 4.0 and 7.0. A minor effect by temperature was observed. The sorption volumes are 19.5 mg/g and 53.5 mg/g from 10 ppm and 40 ppm Sr 2+ solution respectively within 20 min. The sorption of Sr 2+ in these cells can be desorbed under 0.1 mol/L HNO 3 solution. The maximum Sr 2+ sorption volume is 96.7 mg/g at 20℃. The sorption characteristic fits Langmuir model well with 140.8 mg/g calculated maximum sorption volume by these yeast cells. (authors)

Sorting signed permutations by short operations.

Science.gov (United States)

Galvão, Gustavo Rodrigues; Lee, Orlando; Dias, Zanoni

2015-01-01

During evolution, global mutations may alter the order and the orientation of the genes in a genome. Such mutations are referred to as rearrangement events, or simply operations. In unichromosomal genomes, the most common operations are reversals, which are responsible for reversing the order and orientation of a sequence of genes, and transpositions, which are responsible for switching the location of two contiguous portions of a genome. The problem of computing the minimum sequence of operations that transforms one genome into another - which is equivalent to the problem of sorting a permutation into the identity permutation - is a well-studied problem that finds application in comparative genomics. There are a number of works concerning this problem in the literature, but they generally do not take into account the length of the operations (i.e. the number of genes affected by the operations). Since it has been observed that short operations are prevalent in the evolution of some species, algorithms that efficiently solve this problem in the special case of short operations are of interest. In this paper, we investigate the problem of sorting a signed permutation by short operations. More precisely, we study four flavors of this problem: (i) the problem of sorting a signed permutation by reversals of length at most 2; (ii) the problem of sorting a signed permutation by reversals of length at most 3; (iii) the problem of sorting a signed permutation by reversals and transpositions of length at most 2; and (iv) the problem of sorting a signed permutation by reversals and transpositions of length at most 3. We present polynomial-time solutions for problems (i) and (iii), a 5-approximation for problem (ii), and a 3-approximation for problem (iv). Moreover, we show that the expected approximation ratio of the 5-approximation algorithm is not greater than 3 for random signed permutations with more than 12 elements. Finally, we present experimental results that show

Preparation of Immuno-magnetic Beads and Their Separation ＆ Detection to Ovary Cancer Cells

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

The organic monomer-molecule with nanometer magnetic powder by means of reforming the surface of nanometer magnetic powder have been synthesized.Magnetic beads in diameter of 2μm or so are obtained by controlling conditions.Ovary cancer cells of ascites are separated and ovary cancer cells of blood are detected by using immuno-magnetic beads linked with ovary cancer cell mono-antibodies.Results show that the specificity is 85%,sensitivity is 87%,accuracy is 84%,cells acquiring purity is 90%,cells activity is 92% and detection sensitivity is 25×10-7.

Sorting Out Seasonal Allergies

Science.gov (United States)

... Close ‹ Back to Healthy Living Sorting Out Seasonal Allergies Sneezing, runny nose, nasal congestion. Symptoms of the ... How do I know if I have seasonal allergies? According to Dr. Georgeson, the best way to ...

Development of a reactor thermalhydraulic experiment databank(SORTED1)

International Nuclear Information System (INIS)

Bang, Young Seck; Kim, Eun Kyoung; Kim, Hho Jung; Lee, Sang Yong

1994-01-01

The recent trend in thermalhydraulic safety analysis of nuclear power plant shows the best-estimate and probabilistic approaches, therefore, the verification of the best-estimate code based on the applicable experiment data has been required. The present study focused on developing a simple databank, SORTED1, to be effectively used for code verification. The development of SORTED1 includes a data collection from the various sources including ENCOUNTER, which is the reactor safety data bank of U.S. Nuclear Regulatory Commission, a reorganization of collected resources suitable for requirements of SORTED1 database management system (DBMS), and a development of a simple DBMS. The SORTED1 is designed in Unix environment with graphic user interface to improve a user convenience and has a capability to provide the test related information. The currently registered data in SORTED1 cover 759 thermalhydraulic tests including LOFT, Semiscale, etc

Disruption of sorting nexin 5 causes respiratory failure associated with undifferentiated alveolar epithelial type I cells in mice.

Directory of Open Access Journals (Sweden)

Sun-Kyoung Im

Full Text Available Sorting nexin 5 (Snx5 has been posited to regulate the degradation of epidermal growth factor receptor and the retrograde trafficking of cation-independent mannose 6-phosphate receptor/insulin-like growth factor II receptor. Snx5 has also been suggested to interact with Mind bomb-1, an E3 ubiquitin ligase that regulates the activation of Notch signaling. However, the in vivo functions of Snx5 are largely unknown. Here, we report that disruption of the Snx5 gene in mice (Snx5(-/- mice resulted in partial perinatal lethality; 40% of Snx5(-/- mice died shortly after birth due to cyanosis, reduced air space in the lungs, and respiratory failure. Histological analysis revealed that Snx5(-/- mice exhibited thickened alveolar walls associated with undifferentiated alveolar epithelial type I cells. In contrast, alveolar epithelial type II cells were intact, exhibiting normal surfactant synthesis and secretion. Although the expression levels of surfactant proteins and saturated phosphatidylcholine in the lungs of Snx5(-/- mice were comparable to those of Snx5(+/+ mice, the expression levels of T1α, Aqp5, and Rage, markers for distal alveolar epithelial type I cells, were significantly decreased in Snx5 (-/- mice. These results demonstrate that Snx5 is necessary for the differentiation of alveolar epithelial type I cells, which may underlie the adaptation to air breathing at birth.

The Use of Gadolinium-Carbon Nanostructures to Magnetically Enhance Stem Cell Retention for Cellular Cardiomyoplasty

Science.gov (United States)

Tran, Lesa A.; Hernández-Rivera, Mayra; Berlin, Ari N.; Zheng, Yi; Sampaio, Luiz; Bové, Christina; Cabreira-Hansen, Maria da Graça; Willerson, James T.; Perin, Emerson C.; Wilson, Lon J.

2014-01-01

In this work, the effectiveness of using Gadonanotubes (GNTs) with an external magnetic field to improve retention of transplanted adult mesenchymal stem cells (MSCs) during cellular cardiomyoplasty was evaluated. As a high-performance T1-weighted magnetic resonance imaging (MRI) cell tracking label, the GNTs are gadolinium-loaded carbon nanotube capsules that render MSCs magnetic when internalized. MSCs were internally labeled with either superparamagnetic GNTs or colloidal diamagnetic lutetium (Lu). In vitro cell rolling assays and ex vivo cardiac perfusion experiments qualitatively demonstrated increased magnetic-assisted retention of GNT-labeled MSCs. Subsequent in vivo epicardial cell injections were performed around a 1.3 T NdFeB ring magnet sutured onto the left ventricle of female juvenile pigs (n = 21). Cell dosage, magnet exposure time, and endpoints were varied to evaluate the safety and efficacy of the proposed therapy. Quantification of retained cells in collected tissues by elemental analysis (Gd or Lu) showed that the external magnet helped retain nearly three times more GNT-labeled MSCs than Lu-labeled cells. The sutured magnet was tolerated for up to 168 hours; however, an inflammatory response to the magnet was noted after 48 hours. These proof-of-concept studies support the feasibility and value of using GNTs as a magnetic nanoparticle facilitator to improve cell retention during cellular cardiomyoplasty. PMID:24148239

The use of gadolinium-carbon nanostructures to magnetically enhance stem cell retention for cellular cardiomyoplasty.

Science.gov (United States)

Tran, Lesa A; Hernández-Rivera, Mayra; Berlin, Ari N; Zheng, Yi; Sampaio, Luiz; Bové, Christina; Cabreira-Hansen, Maria da Graça; Willerson, James T; Perin, Emerson C; Wilson, Lon J

2014-01-01

In this work, the effectiveness of using Gadonanotubes (GNTs) with an external magnetic field to improve retention of transplanted adult mesenchymal stem cells (MSCs) during cellular cardiomyoplasty was evaluated. As a high-performance T1-weighted magnetic resonance imaging (MRI) cell tracking label, the GNTs are gadolinium-loaded carbon nanotube capsules that render MSCs magnetic when internalized. MSCs were internally labeled with either superparamagnetic GNTs or colloidal diamagnetic lutetium (Lu). In vitro cell rolling assays and ex vivo cardiac perfusion experiments qualitatively demonstrated increased magnetic-assisted retention of GNT-labeled MSCs. Subsequent in vivo epicardial cell injections were performed around a 1.3 T NdFeB ring magnet sutured onto the left ventricle of female juvenile pigs (n = 21). Cell dosage, magnet exposure time, and endpoints were varied to evaluate the safety and efficacy of the proposed therapy. Quantification of retained cells in collected tissues by elemental analysis (Gd or Lu) showed that the external magnet helped retain nearly three times more GNT-labeled MSCs than Lu-labeled cells. The sutured magnet was tolerated for up to 168 h; however, an inflammatory response to the magnet was noted after 48 h. These proof-of-concept studies support the feasibility and value of using GNTs as a magnetic nanoparticle facilitator to improve cell retention during cellular cardiomyoplasty. Copyright © 2013 Elsevier Ltd. All rights reserved.

NeatSort - A practical adaptive algorithm

OpenAIRE

La Rocca, Marcello; Cantone, Domenico

2014-01-01

We present a new adaptive sorting algorithm which is optimal for most disorder metrics and, more important, has a simple and quick implementation. On input $X$, our algorithm has a theoretical $\\Omega (|X|)$ lower bound and a $\\mathcal{O}(|X|\\log|X|)$ upper bound, exhibiting amazing adaptive properties which makes it run closer to its lower bound as disorder (computed on different metrics) diminishes. From a practical point of view, \\textit{NeatSort} has proven itself competitive with (and of...

Queue and stack sorting algorithm optimization and performance analysis

Science.gov (United States)

Qian, Mingzhu; Wang, Xiaobao

2018-04-01

Sorting algorithm is one of the basic operation of a variety of software development, in data structures course specializes in all kinds of sort algorithm. The performance of the sorting algorithm is directly related to the efficiency of the software. A lot of excellent scientific research queue is constantly optimizing algorithm, algorithm efficiency better as far as possible, the author here further research queue combined with stacks of sorting algorithms, the algorithm is mainly used for alternating operation queue and stack storage properties, Thus avoiding the need for a large number of exchange or mobile operations in the traditional sort. Before the existing basis to continue research, improvement and optimization, the focus on the optimization of the time complexity of the proposed optimization and improvement, The experimental results show that the improved effectively, at the same time and the time complexity and space complexity of the algorithm, the stability study corresponding research. The improvement and optimization algorithm, improves the practicability.

[Synergetic killing effects of external magnetic fields combined with porphyrin-dextran magnetic nanoparticles on the human bladder cancer cells].

Science.gov (United States)

Luo, Dao-sheng; Mi, Qi-wu; Meng, Xiang-jun; Gao, Yong; Dai, Yu-ping; Deng, Chun-hua

2012-08-18

To study the synergetic killing effects of external magnetic fields combined with the photodynamic action of porphyrin-dextran iron oxide magnetic nanoparticles (PDMN) on human bladder cancer cells in vitro. The PDMN were produced by using the chemical co-precipitation and redox process and the physicochemical properties were characterized. Methyl thiazolyl tetrazolium (MTT) and flow cytometry were used to determine the effects of photodynamic therapy of PDMN combined with external pulsed electromagnetic fields (5 mT) on killing human bladder cancer BIU-87 cells respectively. The diameters of PDMN were 10-15 nm and the saturation magnetization was 0.20 emu/g. Effective diameter of PDMN was 94.8 nm. PDMN could remarkably inhibit the proliferation and induce the obvious apoptosis of BIU-87 cells, and the rates of growth inhibition and apoptosis were (17.61±2.73)% and (24.53±5.74)% respectively. Moreover, external pulsed electromagnetic fields (5 mT) could also suppress the proliferation and induce apoptosis of BIU-87 cells. Furthermore, the photodynamic action of PDMN combined with external magnetic fields significantly inhibited the proliferation and promote apoptosis of BIU-87 cells, and the rates of growth inhibition and apoptosis was (28.11±4.25)% and (24.53±5.74)%, respectively, which were significantly higher than those of other groups (Peffectively inhibit proliferation and induce apoptosis of BIU-87 cells. Moreover, these effects on BIU-87 cells could be strengthened by the combination with external magnetic fields.

The interaction between Sertoli cells and luekemia inhibitory factor on the propagation and differentiation of spermatogonial stem cells in vitro

Directory of Open Access Journals (Sweden)

Tayebeh Rastegar

2015-11-01

Full Text Available Background: Sertoli cells play a pivotal role in creating microenvironments essential for spermatogonial stem cells (SSCs self-renewal and commitment to differentiation. Maintenance of SSCs and or induction of in vitro spermiogenesis may provide a therapeutic strategy to treat male infertility. Objective: This study investigated the role of luekemia inhibitory factor (LIF on the propagation of SSCs and both functions of Sertoli cells on the proliferation and differentiation of these cells. Materials and Methods: SSCs were sorted from the testes of adult male mice by magnetic activated cell sorting and thymus cell antigen 1 antibody. On the other hand, isolated Sertoli cells were enriched using lectin coated plates. SSCs were cultured on Sertoli cells for 7 days in the absence or presence of LIF. The effects of these conditions were evaluated by microscopy and expression of meiotic and post meiotic transcripts by reverse transcriptase polymerase chain reaction. Results: Our data showed that SSCs co-cultured with Sertoli cells in the presence of LIF formed colonies on top of the Sertoli cells. These colonies had alkaline phosphatesase activity and expressed SSCs specific genes. SSCs were enjoyed limited development after the mere removal of LIF, and exhibiting expression of meiotic and postmeiotic transcript and loss of SSCs specific gene expression (p< 0.05. Conclusion: Our findings represent co-culture of SSCs with Sertoli cells provides conditions that may allow efficient proliferation and differentiation of SSCs for male infertility treatment.

Model design and simulation of automatic sorting machine using proximity sensor

Directory of Open Access Journals (Sweden)

Bankole I. Oladapo

2016-09-01

Full Text Available The automatic sorting system has been reported to be complex and a global problem. This is because of the inability of sorting machines to incorporate flexibility in their design concept. This research therefore designed and developed an automated sorting object of a conveyor belt. The developed automated sorting machine is able to incorporate flexibility and separate species of non-ferrous metal objects and at the same time move objects automatically to the basket as defined by the regulation of the Programmable Logic Controllers (PLC with a capacitive proximity sensor to detect a value range of objects. The result obtained shows that plastic, wood, and steel were sorted into their respective and correct position with an average, sorting, time of 9.903 s, 14.072 s and 18.648 s respectively. The proposed developed model of this research could be adopted at any institution or industries, whose practices are based on mechatronics engineering systems. This is to guide the industrial sector in sorting of object and teaching aid to institutions and hence produce the list of classified materials according to the enabled sorting program commands.

Necrosis of HepG2 cancer cells induced by the vibration of magnetic particles

Energy Technology Data Exchange (ETDEWEB)

Wang, Biran [Laboratoire de Physique de la Matière Condensée (LPMC), CNRS UMR 7336, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice (France); Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, 28 Avenue de Valrose, F-06100 Nice (France); Bienvenu, Céline [Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, 28 Avenue de Valrose, F-06100 Nice (France); Mendez-Garza, Juan; Lançon, Pascal; Madeira, Alexandra [Laboratoire de Physique de la Matière Condensée (LPMC), CNRS UMR 7336, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice (France); Vierling, Pierre [Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, 28 Avenue de Valrose, F-06100 Nice (France); Di Giorgio, Christophe, E-mail: christophe.di-giorgio@unice.fr [Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, 28 Avenue de Valrose, F-06100 Nice (France); Bossis, Georges, E-mail: bossis@unice.fr [Laboratoire de Physique de la Matière Condensée (LPMC), CNRS UMR 7336, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice (France)

2013-10-15

Experiments of magnetolysis, i.e., destruction of cells induced with magnetic particles (MPs) submitted to the application of a magnetic field, were conducted on HepG2 cancer cells. We herein demonstrate the usefulness of combining anisotropic MPs with an alternative magnetic field in magnetolysis. Thus, the application of an alternative magnetic field of low frequency (a few Hertz) in the presence of anisotropic, submicronic particles allowed the destruction of cancer cells “in vitro”. We also show that a constant magnetic field is far less efficient than an oscillating one. Moreover, we demonstrate that, at equal particle volume, it is much more efficient to utilize spindle shaped particles rather than spherical ones. In order to get deeper insight into the mechanism of magnetolysis experiments, we performed a study by AFM, which strongly supports that the magnetic field induces the formation of clusters of particles becoming then large enough todamage cell membranes. - Highlights: • Magnetic force was applied on cancer cells through magnetic particles. • The penetration depth was predicted, both for spherical and ellipsoidal particles. • Alternative force was shown to damage the cells contrary to static force. • The effect of indentation of magnetic particles was compared to the one of AFM tips. • The damage was attributed to the formation of clusters of particles.

Plasma membrane characterization, by scanning electron microscopy, of multipotent myoblasts-derived populations sorted using dielectrophoresis

Energy Technology Data Exchange (ETDEWEB)

Muratore, Massimo, E-mail: M.Muratore@ed.ac.uk [Institute of Integrated Micro and Nano System, School of Engineering, The University of Edinburgh, Edinburgh EH9 3JF (United Kingdom); Mitchell, Steve [Institute of Molecular Plant Science, School of Biological Science, The University of Edinburgh, Edinburgh EH9 3JF (United Kingdom); Waterfall, Martin [Institute of Immunology and Infection Research, School of Biological Science, The University of Edinburgh, Edinburgh EH9 3JT (United Kingdom)

2013-09-06

Highlights: •Dielectrophoretic separation/sorting of multipotent cells. •Plasma membrane microvilli structure of C2C12 and fibroblasts by SEM microscopy. •Cell cycle determination by Ki-67 in DEP-sorted cells. •Plasma membrane differences responsible for changes in membrane capacitance. -- Abstract: Multipotent progenitor cells have shown promise for use in biomedical applications and regenerative medicine. The implementation of such cells for clinical application requires a synchronized, phenotypically and/or genotypically, homogenous cell population. Here we have demonstrated the implementation of a biological tag-free dielectrophoretic device used for discrimination of multipotent myoblastic C2C12 model. The multipotent capabilities in differentiation, for these cells, diminishes with higher passage number, so for cultures above 70 passages only a small percentage of cells is able to differentiate into terminal myotubes. In this work we demonstrated that we could recover, above 96% purity, specific cell types from a mixed population of cells at high passage number without any biological tag using dielectrophoresis. The purity of the samples was confirmed by cytometric analysis using the cell specific marker embryonic myosin. To further investigate the dielectric properties of the cell plasma membrane we co-culture C2C12 with similar size, when in suspension, GFP-positive fibroblast as feeder layer. The level of separation between the cell types was above 98% purity which was confirmed by flow cytometry. These levels of separation are assumed to account for cell size and for the plasma membrane morphological differences between C2C12 and fibroblast unrelated to the stages of the cell cycle which was assessed by immunofluorescence staining. Plasma membrane conformational differences were further confirmed by scanning electron microscopy.

Plasma membrane characterization, by scanning electron microscopy, of multipotent myoblasts-derived populations sorted using dielectrophoresis

International Nuclear Information System (INIS)

Muratore, Massimo; Mitchell, Steve; Waterfall, Martin

2013-01-01

Highlights: •Dielectrophoretic separation/sorting of multipotent cells. •Plasma membrane microvilli structure of C2C12 and fibroblasts by SEM microscopy. •Cell cycle determination by Ki-67 in DEP-sorted cells. •Plasma membrane differences responsible for changes in membrane capacitance. -- Abstract: Multipotent progenitor cells have shown promise for use in biomedical applications and regenerative medicine. The implementation of such cells for clinical application requires a synchronized, phenotypically and/or genotypically, homogenous cell population. Here we have demonstrated the implementation of a biological tag-free dielectrophoretic device used for discrimination of multipotent myoblastic C2C12 model. The multipotent capabilities in differentiation, for these cells, diminishes with higher passage number, so for cultures above 70 passages only a small percentage of cells is able to differentiate into terminal myotubes. In this work we demonstrated that we could recover, above 96% purity, specific cell types from a mixed population of cells at high passage number without any biological tag using dielectrophoresis. The purity of the samples was confirmed by cytometric analysis using the cell specific marker embryonic myosin. To further investigate the dielectric properties of the cell plasma membrane we co-culture C2C12 with similar size, when in suspension, GFP-positive fibroblast as feeder layer. The level of separation between the cell types was above 98% purity which was confirmed by flow cytometry. These levels of separation are assumed to account for cell size and for the plasma membrane morphological differences between C2C12 and fibroblast unrelated to the stages of the cell cycle which was assessed by immunofluorescence staining. Plasma membrane conformational differences were further confirmed by scanning electron microscopy

Two-sorted Point-Interval Temporal Logics

DEFF Research Database (Denmark)

Balbiani, Philippe; Goranko, Valentin; Sciavicco, Guido

2011-01-01

There are two natural and well-studied approaches to temporal ontology and reasoning: point-based and interval-based. Usually, interval-based temporal reasoning deals with points as particular, duration-less intervals. Here we develop explicitly two-sorted point-interval temporal logical framework...... whereby time instants (points) and time periods (intervals) are considered on a par, and the perspective can shift between them within the formal discourse. We focus on fragments involving only modal operators that correspond to the inter-sort relations between points and intervals. We analyze...

Magnetic assembly of 3D cell clusters: visualizing the formation of an engineered tissue.

Science.gov (United States)

Ghosh, S; Kumar, S R P; Puri, I K; Elankumaran, S

2016-02-01

Contactless magnetic assembly of cells into 3D clusters has been proposed as a novel means for 3D tissue culture that eliminates the need for artificial scaffolds. However, thus far its efficacy has only been studied by comparing expression levels of generic proteins. Here, it has been evaluated by visualizing the evolution of cell clusters assembled by magnetic forces, to examine their resemblance to in vivo tissues. Cells were labeled with magnetic nanoparticles, then assembled into 3D clusters using magnetic force. Scanning electron microscopy was used to image intercellular interactions and morphological features of the clusters. When cells were held together by magnetic forces for a single day, they formed intercellular contacts through extracellular fibers. These kept the clusters intact once the magnetic forces were removed, thus serving the primary function of scaffolds. The cells self-organized into constructs consistent with the corresponding tissues in vivo. Epithelial cells formed sheets while fibroblasts formed spheroids and exhibited position-dependent morphological heterogeneity. Cells on the periphery of a cluster were flattened while those within were spheroidal, a well-known characteristic of connective tissues in vivo. Cells assembled by magnetic forces presented visual features representative of their in vivo states but largely absent in monolayers. This established the efficacy of contactless assembly as a means to fabricate in vitro tissue models. © 2016 John Wiley & Sons Ltd.

Improved Imaging of Magnetically Labeled Cells Using Rotational Magnetomotive Optical Coherence Tomography

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Peter Cimalla

2017-04-01

Full Text Available In this paper, we present a reliable and robust method for magnetomotive optical coherence tomography (MM-OCT imaging of single cells labeled with iron oxide particles. This method employs modulated longitudinal and transverse magnetic fields to evoke alignment and rotation of anisotropic magnetic structures in the sample volume. Experimental evidence suggests that magnetic particles assemble themselves in elongated chains when exposed to a permanent magnetic field. Magnetomotion in the intracellular space was detected and visualized by means of 3D OCT as well as laser speckle reflectometry as a 2D reference imaging method. Our experiments on mesenchymal stem cells embedded in agar scaffolds show that the magnetomotive signal in rotational MM-OCT is significantly increased by a factor of ~3 compared to previous pulsed MM-OCT, although the solenoid’s power consumption was 16 times lower. Finally, we use our novel method to image ARPE-19 cells, a human retinal pigment epithelium cell line. Our results permit magnetomotive imaging with higher sensitivity and the use of low power magnetic fields or larger working distances for future three-dimensional cell tracking in target tissues and organs.

A magnetically responsive nanocomposite scaffold combined with Schwann cells promotes sciatic nerve regeneration upon exposure to magnetic field

Directory of Open Access Journals (Sweden)

Liu ZY

2017-10-01

Full Text Available Zhongyang Liu,1,* Shu Zhu,1,* Liang Liu,2,* Jun Ge,3,4,* Liangliang Huang,1 Zhen Sun,1 Wen Zeng,5 Jinghui Huang,1 Zhuojing Luo1 1Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, 2Department of Orthopedics, No 161 Hospital of PLA, Wuhan, Hubei, 3Department of Orthopedics, No 323 Hospital of PLA, Xi’an, Shaanxi, 4Department of Anatomy, Fourth Military Medical University, Xi’an, Shaanxi, 5Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi’an, Shaanxi, People’s Republic of China *These authors contributed equally to this work Abstract: Peripheral nerve repair is still challenging for surgeons. Autologous nerve transplantation is the acknowledged therapy; however, its application is limited by the scarcity of available donor nerves, donor area morbidity, and neuroma formation. Biomaterials for engineering artificial nerves, particularly materials combined with supportive cells, display remarkable promising prospects. Schwann cells (SCs are the absorbing seeding cells in peripheral nerve engineering repair; however, the attenuated biologic activity restricts their application. In this study, a magnetic nanocomposite scaffold fabricated from magnetic nanoparticles and a biodegradable chitosan–glycerophosphate polymer was made. Its structure was evaluated and characterized. The combined effects of magnetic scaffold (MG with an applied magnetic field (MF on the viability of SCs and peripheral nerve injury repair were investigated. The magnetic nanocomposite scaffold showed tunable magnetization and degradation rate. The MGs synergized with the applied MF to enhance the viability of SCs after transplantation. Furthermore, nerve regeneration and functional recovery were promoted by the synergism of SCs-loaded MGs and MF. Based on the current findings, the combined application of MGs and SCs with applied MF is a promising therapy for the engineering of peripheral

Sorting on STAR. [CDC computer algorithm timing comparison

Science.gov (United States)

Stone, H. S.

1978-01-01

Timing comparisons are given for three sorting algorithms written for the CDC STAR computer. One algorithm is Hoare's (1962) Quicksort, which is the fastest or nearly the fastest sorting algorithm for most computers. A second algorithm is a vector version of Quicksort that takes advantage of the STAR's vector operations. The third algorithm is an adaptation of Batcher's (1968) sorting algorithm, which makes especially good use of vector operations but has a complexity of N(log N)-squared as compared with a complexity of N log N for the Quicksort algorithms. In spite of its worse complexity, Batcher's sorting algorithm is competitive with the serial version of Quicksort for vectors up to the largest that can be treated by STAR. Vector Quicksort outperforms the other two algorithms and is generally preferred. These results indicate that unusual instruction sets can introduce biases in program execution time that counter results predicted by worst-case asymptotic complexity analysis.

Unsupervised spike sorting based on discriminative subspace learning.

Science.gov (United States)

Keshtkaran, Mohammad Reza; Yang, Zhi

2014-01-01

Spike sorting is a fundamental preprocessing step for many neuroscience studies which rely on the analysis of spike trains. In this paper, we present two unsupervised spike sorting algorithms based on discriminative subspace learning. The first algorithm simultaneously learns the discriminative feature subspace and performs clustering. It uses histogram of features in the most discriminative projection to detect the number of neurons. The second algorithm performs hierarchical divisive clustering that learns a discriminative 1-dimensional subspace for clustering in each level of the hierarchy until achieving almost unimodal distribution in the subspace. The algorithms are tested on synthetic and in-vivo data, and are compared against two widely used spike sorting methods. The comparative results demonstrate that our spike sorting methods can achieve substantially higher accuracy in lower dimensional feature space, and they are highly robust to noise. Moreover, they provide significantly better cluster separability in the learned subspace than in the subspace obtained by principal component analysis or wavelet transform.

A Quality Sorting of Fruit Using a New Automatic Image Processing Method

Science.gov (United States)

Amenomori, Michihiro; Yokomizu, Nobuyuki

This paper presents an innovative approach for quality sorting of objects such as apples sorting in an agricultural factory, using an image processing algorithm. The objective of our approach are; firstly to sort the objects by their colors precisely; secondly to detect any irregularity of the colors surrounding the apples efficiently. An experiment has been conducted and the results have been obtained and compared with that has been preformed by human sorting process and by color sensor sorting devices. The results demonstrate that our approach is capable to sort the objects rapidly and the percentage of classification valid rate was 100 %.

Gender Sorting across K-12 Schools in the United States

Science.gov (United States)

Long, Mark C.; Conger, Dylan

2013-01-01

This article documents evidence of nonrandom gender sorting across K-12 schools in the United States. The sorting exists among coed schools and at all grade levels, and it is highest in the secondary school grades. We observe some gender sorting across school sectors and types: for instance, males are slightly underrepresented in private schools…

Aptamer-based isolation and subsequent imaging of mesenchymal stem cells in ischemic myocard by magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Schaefer, R.; Hermanutz-Klein, U.; Northoff, H. [Universitaetsklinikum Tuebingen (Germany). Inst. fuer Klinische und Experimentelle Transfusionsmedizin; Wiskirchen, J.; Kehlbach, R.; Pintaske, J. [Universitaetsklinikum Tuebingen (Germany). Abt. fuer Radiologische Diagnostik; Guo, K.; Neumann, B.; Voth, V.; Walker, T.; Scheule, A.M.; Greiner, T.O.; Ziemer, G.; Wendel, H.P. [Universitaetsklinikum Tuebingen (Germany). Abt. fuer Thorax-, Herz- und Gefaesschirurgie; Claussen, C.D. [Universitaetsklinikum Tuebingen (Germany). Radiologische Universitaetsklinik

2007-10-15

Purpose: Mesenchymal stem cells (MSC) seem to be a promising cell source for cellular cardiomyoplasty. We recently developed a new aptamer-based specific selection of MSC to provide ''ready to transplant'' cells directly after isolation. We evaluated MRI tracking of newly isolated and freshly transplanted MSC in the heart using one short ex vivo selection step combining specific aptamer-based isolation and labeling of the cells. Materials and Methods: Bone marrow (BM) was collected from healthy pigs. The animals were euthanized and the heart was placed in a perfusion model. During cold ischemia, immunomagnetic isolation of MSC from the BM by MSC-specific aptamers labeled with Dynabeads {sup registered} was performed within 2 h. For histological identification the cells were additionally stained with PKH26. Approx. 3 x 10{sup 6} of the freshly aptamer-isolated cells were injected into the ramus interventricularis anterior (RIVA) and 5 x 10{sup 5} cells were injected directly into myocardial tissue after damaging the respective area by freezing (cryo-scar). 3 x 10{sup 6} of the aptamer-isolated cells were kept for further characterization (FACS and differentiation assays). 20 h after cell transplantation, MRI of the heart using a clinical 3.0 Tesla whole body scanner (Magnetom Trio, Siemens, Germany) was performed followed by histological examinations. Results: The average yield of sorted cells from 120 ml BM was 7 x 10{sup 6} cells. The cells were cultured and showed MSC-like properties. MRI showed reproducible artifacts within the RIVA-perfusion area and the cryo-scar with surprisingly excellent quality. The histological examination of the biopsies showed PKH26-positive cells within the areas which were positive in the MRI in contrast to the control biopsies. Conclusion: Immunomagnetic separation of MSC by specific aptamers linked to magnetic particles is feasible, effective and combines a specific separation and labeling technique to a &apos

Software information sorting code 'PLUTO-R'

International Nuclear Information System (INIS)

Tsunematsu, Toshihide; Naraoka, Kenitsu; Adachi, Masao; Takeda, Tatsuoki

1984-10-01

A software information sorting code PLUTO-R is developed as one of the supporting codes of the TRITON system for the fusion plasma analysis. The objective of the PLUTO-R code is to sort reference materials of the codes in the TRITON code system. The easiness in the registration of information is especially pursued. As experience and skill in the data registration are not required, this code is usable for construction of general small-scale information system. This report gives an overall description and the user's manual of the PLUTO-R code. (author)

Sorting signed permutations by inversions in O(nlogn) time.

Science.gov (United States)

Swenson, Krister M; Rajan, Vaibhav; Lin, Yu; Moret, Bernard M E

2010-03-01

The study of genomic inversions (or reversals) has been a mainstay of computational genomics for nearly 20 years. After the initial breakthrough of Hannenhalli and Pevzner, who gave the first polynomial-time algorithm for sorting signed permutations by inversions, improved algorithms have been designed, culminating with an optimal linear-time algorithm for computing the inversion distance and a subquadratic algorithm for providing a shortest sequence of inversions--also known as sorting by inversions. Remaining open was the question of whether sorting by inversions could be done in O(nlogn) time. In this article, we present a qualified answer to this question, by providing two new sorting algorithms, a simple and fast randomized algorithm and a deterministic refinement. The deterministic algorithm runs in time O(nlogn + kn), where k is a data-dependent parameter. We provide the results of extensive experiments showing that both the average and the standard deviation for k are small constants, independent of the size of the permutation. We conclude (but do not prove) that almost all signed permutations can be sorted by inversions in O(nlogn) time.

The overexpressed human 46-kDa mannose 6-phosphate receptor mediates endocytosis and sorting of β-glucuronidase

International Nuclear Information System (INIS)

Watanabe, H.; Grubb, J.H.; Sly, W.S.

1990-01-01

The authors studied the function of the human small (46-kDa) mannose 6-phosphate receptor (SMPR) in transfected mouse L cells that do not express the larger insulin-like growth factor II/mannose 6-phosphate receptor. Cells overexpressing human SMPR were studied for enzyme binding to cell surface receptors, for binding to intracellular receptors in permeabilized cells, and for receptor-mediated endocytosis of recombinant human β-glucuronidase. Specific binding to human SMPR in permeabilized cells showed a pH optimum between pH 6.0 and pH 6.5. Binding was significant in the present of EDTA but was enhanced by added divalent cations. Up to 2.3% of the total functional receptor could be detected on the cell surface by enzyme binding. They present experiments showing that at very high levels of overexpression, and at pH 6.5, human SMPR mediated the endocytosis of β-glucuronidase. At pH 7.5, the rate of endocytosis was only 14% the rate seen at pH 6.5. Cells overexpressing human SMPR also showed reduced secretion of newly synthesized β-glucuronidase when compared to cells transfected with vector only, suggesting that overexpressed human SMPR can participate in sorting of newly synthesized β-glucuronidase and partially correct the sorting defect in mouse L cells that do not express the insulin-like growth factor II/mannose 6-phosphate receptor

Comparative analysis of circulating endothelial progenitor cells in age-related macular degeneration patients using automated rare cell analysis (ARCA and fluorescence activated cell sorting (FACS.

Directory of Open Access Journals (Sweden)

Emil Anthony T Say

Full Text Available BACKGROUND: Patients with age-related macular degeneration (ARMD begin with non-neovascular (NNV phenotypes usually associated with good vision. Approximately 20% of NNV-ARMD patients will convert to vision debilitating neovascular (NV ARMD, but precise timing of this event is unknown. Developing a clinical test predicting impending conversion to NV-ARMD is necessary to prevent vision loss. Endothelial progenitor cells (EPCs, defined as CD34(+VEGR2(+ using traditional fluorescence activated cell sorting (FACS, are rare cell populations known to be elevated in patients with NV-ARMD compared to NNV-ARMD. FACS has high inter-observer variability and subjectivity when measuring rare cell populations precluding development into a diagnostic test. We hypothesized that automated rare cell analysis (ARCA, a validated and FDA-approved technology for reproducible rare cell identification, can enumerate EPCs in ARMD patients more reliably. This pilot study serves as the first step in developing methods for reproducibly predicting ARMD phenotype conversion. METHODS: We obtained peripheral venous blood samples in 23 subjects with NNV-ARMD or treatment naïve NV-ARMD. Strict criteria were used to exclude subjects with known angiogenic diseases to minimize confounding results. Blood samples were analyzed in masked fashion in two separate laboratories. EPCs were independently enumerated using ARCA and FACS within 24 hours of blood sample collection, and p<0.2 was considered indicative of a trend for this proof of concept study, while statistical significance was established at 0.05. RESULTS: We measured levels of CD34(+VEGFR2(+ EPCs suggestive of a trend with higher values in patients with NV compared to NNV-ARMD (p = 0.17 using ARCA. Interestingly, CD34(+VEGR2(+ EPC analysis using FACS did not produce similar results (p = 0.94. CONCLUSIONS: CD34(+VEGR2(+ may have predictive value for EPC enumeration in future ARCA studies. EPC measurements in a small sample

Comparative analysis of circulating endothelial progenitor cells in age-related macular degeneration patients using automated rare cell analysis (ARCA) and fluorescence activated cell sorting (FACS).

Science.gov (United States)

Say, Emil Anthony T; Melamud, Alex; Esserman, Denise Ann; Povsic, Thomas J; Chavala, Sai H

2013-01-01

Patients with age-related macular degeneration (ARMD) begin with non-neovascular (NNV) phenotypes usually associated with good vision. Approximately 20% of NNV-ARMD patients will convert to vision debilitating neovascular (NV) ARMD, but precise timing of this event is unknown. Developing a clinical test predicting impending conversion to NV-ARMD is necessary to prevent vision loss. Endothelial progenitor cells (EPCs), defined as CD34(+)VEGR2(+) using traditional fluorescence activated cell sorting (FACS), are rare cell populations known to be elevated in patients with NV-ARMD compared to NNV-ARMD. FACS has high inter-observer variability and subjectivity when measuring rare cell populations precluding development into a diagnostic test. We hypothesized that automated rare cell analysis (ARCA), a validated and FDA-approved technology for reproducible rare cell identification, can enumerate EPCs in ARMD patients more reliably. This pilot study serves as the first step in developing methods for reproducibly predicting ARMD phenotype conversion. We obtained peripheral venous blood samples in 23 subjects with NNV-ARMD or treatment naïve NV-ARMD. Strict criteria were used to exclude subjects with known angiogenic diseases to minimize confounding results. Blood samples were analyzed in masked fashion in two separate laboratories. EPCs were independently enumerated using ARCA and FACS within 24 hours of blood sample collection, and ptrend for this proof of concept study, while statistical significance was established at 0.05. We measured levels of CD34(+)VEGFR2(+) EPCs suggestive of a trend with higher values in patients with NV compared to NNV-ARMD (p = 0.17) using ARCA. Interestingly, CD34(+)VEGR2(+) EPC analysis using FACS did not produce similar results (p = 0.94). CD34(+)VEGR2(+) may have predictive value for EPC enumeration in future ARCA studies. EPC measurements in a small sample size were suggestive of a trend in ARMD using ARCA but not FACS. ARCA could be a