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Sample records for plate cells produce

  1. Correlation between standard plate count and somatic cell count milk quality results for Wisconsin dairy producers.

    Science.gov (United States)

    Borneman, Darand L; Ingham, Steve

    2014-05-01

    The objective of this study was to determine if a correlation exists between standard plate count (SPC) and somatic cell count (SCC) monthly reported results for Wisconsin dairy producers. Such a correlation may indicate that Wisconsin producers effectively controlling sanitation and milk temperature (reflected in low SPC) also have implemented good herd health management practices (reflected in low SCC). The SPC and SCC results for all grade A and B dairy producers who submitted results to the Wisconsin Department of Agriculture, Trade, and Consumer Protection, in each month of 2012 were analyzed. Grade A producer SPC results were less dispersed than grade B producer SPC results. Regression analysis showed a highly significant correlation between SPC and SCC, but the R(2) value was very small (0.02-0.03), suggesting that many other factors, besides SCC, influence SPC. Average SCC (across 12 mo) for grade A and B producers decreased with an increase in the number of monthly SPC results (out of 12) that were ≤ 25,000 cfu/mL. A chi-squared test of independence showed that the proportion of monthly SCC results >250,000 cells/mL varied significantly depending on whether the corresponding SPC result was ≤ 25,000 or >25,000 cfu/mL. This significant difference occurred in all months of 2012 for grade A and B producers. The results suggest that a generally consistent level of skill exists across dairy production practices affecting SPC and SCC.

  2. Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

    Energy Technology Data Exchange (ETDEWEB)

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-04-08

    A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.

  3. Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

    Science.gov (United States)

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-04-08

    A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.

  4. Corrosion test cell for bipolar plates

    Science.gov (United States)

    Weisbrod, Kirk R.

    2002-01-01

    A corrosion test cell for evaluating corrosion resistance in fuel cell bipolar plates is described. The cell has a transparent or translucent cell body having a pair of identical cell body members that seal against opposite sides of a bipolar plate. The cell includes an anode chamber and an cathode chamber, each on opposite sides of the plate. Each chamber contains a pair of mesh platinum current collectors and a catalyst layer pressed between current collectors and the plate. Each chamber is filled with an electrolyte solution that is replenished with fluid from a much larger electrolyte reservoir. The cell includes gas inlets to each chamber for hydrogen gas and air. As the gases flow into a chamber, they pass along the platinum mesh, through the catalyst layer, and to the bipolar plate. The gas exits the chamber through passageways that provide fluid communication between the anode and cathode chambers and the reservoir, and exits the test cell through an exit port in the reservoir. The flow of gas into the cell produces a constant flow of fresh electrolyte into each chamber. Openings in each cell body is member allow electrodes to enter the cell body and contact the electrolyte in the reservoir therein. During operation, while hydrogen gas is passed into one chamber and air into the other chamber, the cell resistance is measured, which is used to evaluate the corrosion properties of the bipolar plate.

  5. Methods for identifying lipoxygenase producing microorganisms on agar plates

    NARCIS (Netherlands)

    Nyyssola, A.; Heshof, R.; Haarmann, T.; Eidner, J.; Westerholm-Parvinen, A.; Langfelder, K.; Kruus, K.; Graaff, de L.H.; Buchert, J.

    2012-01-01

    Plate assays for lipoxygenase producing microorganisms on agar plates have been developed. Both potassium iodide-starch and indamine dye formation methods were effective for detecting soybean lipoxygenase activity on agar plates. A positive result was also achieved using the beta-carotene bleaching

  6. Instrument modifications that produced reduced plate heights supercritical fluid chromatography.

    Science.gov (United States)

    Berger, Terry A

    2016-04-29

    The concept of peak fidelity was shown to be helpful in modeling tubing and detector cell dimensions. Connection tubing and flow cell variances were modeled to determine appropriate internal ID's, lengths, and volumes. A low dispersion plumbing configuration, based on these calculations, was assembled to replace the standard plumbing and produced the reported results. The modifications made were straightforward using commercially available parts. The full theoretical efficiency of a 3×100 mm column packed with 1.8 μm totally porous particles was achieved for the first time in supercritical fluid chromatography (SFC). Peak fidelity of >0.95 was maintained to below k=2. A reduced plate height as low as 1.87 was measured. Thus, true "ultra high performance" SFC was achieved, with the results a major improvement from all previous SFC reports. Since there were no efficiency losses, none could be attributed to thermal gradients caused by the expansion of the fluid over large pressure drops, under the conditions used. Similarly, changes in diffusion coefficients caused by significant decreases in density during expansion are apparently balanced by the increase in linear velocity, keeping the ratio between the diffusion coefficient and the linear velocity a constant. Changing modifier concentration to change retention was shown to not be a significant problem. All these issues have been a concern in the past. Diffusion coefficients, and viscosity data needs to be collected at high pressures before the actual limits of SFC can be discovered.

  7. Capacity planning in operations producing heavy plate cut shapes

    Directory of Open Access Journals (Sweden)

    R. Lenort

    2009-07-01

    Full Text Available The present approach to capacity planning in operations producing heavy metal shapes causes problems in fulfilling the required financial and volume indexes in production, as well as in meeting the work order completion dates. The article represents the methodology for optimal production scheduling in operations producing heavy plate cut shapes, which significantly eliminates the above-mentioned problems. The methodology is based on the application Generalized Assignment Problem (GAP.

  8. Methods for identifying lipoxygenase producing microorganisms on agar plates.

    Science.gov (United States)

    Nyyssölä, Antti; Heshof, Ruud; Haarmann, Thomas; Eidner, Jasmin; Westerholm-Parvinen, Ann; Langfelder, Kim; Kruus, Kristiina; de Graaff, Leo; Buchert, Johanna

    2012-03-26

    Plate assays for lipoxygenase producing microorganisms on agar plates have been developed. Both potassium iodide-starch and indamine dye formation methods were effective for detecting soybean lipoxygenase activity on agar plates. A positive result was also achieved using the β-carotene bleaching method, but the sensitivity of this method was lower than the other two methods. The potassium iodide-starch and indamine dye formation methods were also applied for detecting lipoxygenase production by Trichoderma reesei and Pichia pastoris transformants expressing the lipoxygenase gene of the fungus Gaeumannomyces graminis. In both cases lipoxygenase production in the transformants could be identified. For detection of the G. graminis lipoxygenase produced by Aspergillus nidulans the potassium iodide-starch method was successful. When Escherichia coli was grown on agar and soybean lipoxygenase was applied on the culture lipoxygenase activity could clearly be detected by the indamine dye formation method. This suggests that the method has potential for screening of metagenomic libraries in E. coli for lipoxygenase activity.

  9. Fuel Cell Thermal Management Through Conductive Cooling Plates

    Science.gov (United States)

    Colozza, Anthony J.; Burke, Kenneth A.

    2008-01-01

    An analysis was performed to evaluate the concept of utilizing conductive cooling plates to remove heat from a fuel cell stack, as opposed to a conventional internal cooling loop. The potential advantages of this type of cooling system are reduced stack complexity and weight and increased reliability through the reduction of the number of internal fluid seals. The conductive cooling plates would extract heat from the stack transferring it to an external coolant loop. The analysis was performed to determine the required thickness of these plates. The analysis was based on an energy balance between the thermal energy produced within the stack and the heat removal from the cooling plates. To accomplish the energy balance, the heat flow into and along the plates to the cooling fluid was modeled. Results were generated for various numbers of cells being cooled by a single cooling plate. The results provided cooling plate thickness, mass, and operating temperature of the plates. It was determined that utilizing high-conductivity pyrolitic graphite cooling plates can provide a specific cooling capacity (W/kg) equivalent to or potentially greater than a conventional internal cooling loop system.

  10. Characterization of vortical gusts produced by a heaving plate

    Science.gov (United States)

    Hufstedler, Esteban; McKeon, Beverley J.

    2016-11-01

    To experimentally investigate the interaction between a wing and a spanwise vortical gust, a simple gust generator has been built and tested. This consists of a transversely heaving flat plate that changes direction to release a vortex, which then convects downstream to interact with a wing. Previous experiments have shown that, immediately downstream of the plate, the circulation of the generated vortex is proportional to the heaving speed of the plate. The forces that the gusts exert on a downstream wing were shown to be strongly repeatable and consistent with a passing vortex. This presentation will discuss the properties of the vortical gusts as they move downstream, and relate those properties to the important dimensionless parameters of the flow. These properties include the convection speed and circulation of the vortex, as well as the enstrophy due to the wake of the plate. This research is funded by the Gordon and Betty Moore Foundation through Grant GBMF#2645 to the California Institute of Technology.

  11. Endocrine cells producing regulatory peptides.

    Science.gov (United States)

    Solcia, E; Usellini, L; Buffa, R; Rindi, G; Villani, L; Zampatti, C; Silini, E

    1987-07-15

    Recent data on the immunolocalization of regulatory peptides and related propeptide sequences in endocrine cells and tumors of the gastrointestinal tract, pancreas, lung, thyroid, pituitary (ACTH and opioids), adrenals and paraganglia have been revised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory polypeptide), neurotensin, glicentin/glucagon-37 and PYY (peptide tyrosine tyrosine) are the main products of gastrointestinal endocrine cells; glucagon, CRF (corticotropin releasing factor), somatostatin, PP (pancreatic polypeptide) and GRF (growth hormone releasing factor), in addition to insulin, are produced in pancreatic islet cells; bombesin-related peptides are the main markers of pulmonary endocrine cells; calcitonin and CGRP (calcitonin gene-related peptide) occur in thyroid and extrathyroid C cells; ACTH and endorphins in anterior and intermediate lobe pituitary cells, alpha-MSH and CLIP (corticotropin-like intermediate lobe peptide) in intermediate lobe cells; met- and leu-enkephalins and related peptides in adrenal medullary and paraganglionic cells as well as in some gut (enterochromaffin) cells; NPY (neuropeptide Y) in adrenaline-type adrenal medullary cells, etc.. Both tissue-appropriate and tissue-inappropriate regulatory peptides are produced by endocrine tumours, with inappropriate peptides mostly produced by malignant tumours.

  12. Composite Bipolar Plate for Unitized Fuel Cell/Electrolyzer Systems

    Science.gov (United States)

    Mittelsteadt, Cortney K.; Braff, William

    2009-01-01

    In a substantial improvement over present alkaline systems, an advanced hybrid bipolar plate for a unitized fuel cell/electrolyzer has been developed. This design, which operates on pure feed streams (H2/O2 and water, respectively) consists of a porous metallic foil filled with a polymer that has very high water transport properties. Combined with a second metallic plate, the pore-filled metallic plates form a bipolar plate with an empty cavity in the center.

  13. Highly conductive composites for fuel cell flow field plates and bipolar plates

    Science.gov (United States)

    Jang, Bor Z; Zhamu, Aruna; Song, Lulu

    2014-10-21

    This invention provides a fuel cell flow field plate or bipolar plate having flow channels on faces of the plate, comprising an electrically conductive polymer composite. The composite is composed of (A) at least 50% by weight of a conductive filler, comprising at least 5% by weight reinforcement fibers, expanded graphite platelets, graphitic nano-fibers, and/or carbon nano-tubes; (B) polymer matrix material at 1 to 49.9% by weight; and (C) a polymer binder at 0.1 to 10% by weight; wherein the sum of the conductive filler weight %, polymer matrix weight % and polymer binder weight % equals 100% and the bulk electrical conductivity of the flow field or bipolar plate is at least 100 S/cm. The invention also provides a continuous process for cost-effective mass production of the conductive composite-based flow field or bipolar plate.

  14. PEM fuel cell bipolar plate material requirements for transportation applications

    Energy Technology Data Exchange (ETDEWEB)

    Borup, R.L.; Stroh, K.R.; Vanderborgh, N.E. [Los Alamos National Lab., NM (United States)] [and others

    1996-04-01

    Cost effective bipolar plates are currently under development to help make proton exchange membrane (PEM) fuel cells commercially viable. Bipolar plates separate individual cells of the fuel cell stack, and thus must supply strength, be electrically conductive, provide for thermal control of the fuel stack, be a non-porous materials separating hydrogen and oxygen feed streams, be corrosion resistant, provide gas distribution for the feed streams and meet fuel stack cost targets. Candidate materials include conductive polymers and metal plates with corrosion resistant coatings. Possible metals include aluminium, titanium, iron/stainless steel and nickel.

  15. A simple plate-assay for the screening of L-malic acid producing microorganisms.

    Science.gov (United States)

    Peleg, Y; Rokem, J S; Goldberg, I

    1990-02-01

    A simple plate-assay has been developed to screen microorganisms for L-malic acid production. Acid producing organisms were identified, after microbial colony growth on media containing glucose or fumaric acid as sole carbons sources, by formation of a dark halo of formazan. The halo was observed when the plate was covered with a soft agar overlay containing NAD(+)-malate dehydrogenase, NAD+, phenazine methosulfate (PMS) and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT). The assay developed is simple, specific for L-malic acid and therefore can be used to identify L-malic acid producing filamentous fungi using glucose as carbon source (e.g. Aspergillus strains). The assay is also applicable for screening bacteria with high fumarase activity, able to convert fumaric acid to L-malic acid.

  16. Highly conductive thermoplastic composites for rapid production of fuel cell bipolar plates

    Science.gov (United States)

    Huang, Jianhua [Blacksburg, VA; Baird, Donald G [Blacksburg, VA; McGrath, James E [Blacksburg, VA

    2008-04-29

    A low cost method of fabricating bipolar plates for use in fuel cells utilizes a wet lay process for combining graphite particles, thermoplastic fibers, and reinforcing fibers to produce a plurality of formable sheets. The formable sheets are then molded into a bipolar plates with features impressed therein via the molding process. The bipolar plates formed by the process have conductivity in excess of 150 S/cm and have sufficient mechanical strength to be used in fuel cells. The bipolar plates can be formed as a skin/core laminate where a second polymer material is used on the skin surface which provides for enhanced conductivity, chemical resistance, and resistance to gas permeation.

  17. Microscopic studies of the influence of main exposure time on parameters of flexographic printing plate produced by digital thermal method.

    Science.gov (United States)

    Harri, Liliya

    2009-10-01

    The digital thermal technology of producing flexographic printing plates from photopolymer plates is one of the newest technologies. This technology allows to develop flexographic plates without the use of any solvent. The process of producing flexographic printing plates by the digital thermal method consists of several main stages: back exposure, laser exposure, main exposure, thermal development, post exposure, and light finishing. The studies carried out with the use of optical stereoscopic microscopy allowed to determine the effect of time of main exposure to ultraviolet radiation on the dot area, diameter, and edge factor of halftone dots reproduced on flexographic printing plate produced by the digital thermal method, as well as on the quality of reproducing the surface and on the profiles of free-standing printing microelements. The results of the microscopic studies performed have allowed to define the criteria of establishing optimum time of main exposure of photopolymer plates used in the digital thermal technology of producing flexographic printing plates. A precise definition of the criteria for determining the optimum time of main exposure will enable to reduce the time-consuming control tests and to eliminate errors in both the process of manufacturing flexographic printing plates and in the printing process carried out with the use of such plates.

  18. Carbon composite bipolar plate for high-temperature proton exchange membrane fuel cells (HT-PEMFCs)

    Science.gov (United States)

    Lee, Dongyoung; Lee, Dai Gil

    2016-09-01

    A carbon/epoxy composite bipolar plate is an ideal substitute for the brittle graphite bipolar plate for lightweight proton exchange membrane fuel cells (PEMFCs) because of its high specific strength and stiffness. However, conventional carbon/epoxy composite bipolar plates are not applicable for high-temperature PEMFCs (HT-PEMFCs) because these systems are operated at higher temperatures than the glass transition temperatures of conventional epoxies. Therefore, in this study, a cyanate ester-modified epoxy is adopted for the development of a carbon composite bipolar plate for HT-PEMFCs. The composite bipolar plate with exposed surface carbon fibers is produced without any surface treatments or coatings to increase the productivity and is integrated with a silicone gasket to reduce the assembly cost. The developed carbon composite bipolar plate exhibits not only superior electrical properties but also high thermo-mechanical properties. In addition, a unit cell test is performed, and the results are compared with those of the conventional graphite bipolar plate.

  19. Low Cost PEM Fuel Cell Metal Bipolar Plates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Conghua [TreadStone Technologies, Inc.

    2013-05-30

    Bipolar plate is an important component in fuel cell stacks and accounts for more than 75% of stack weight and volume. The technology development of metal bipolar plates can effectively reduce the fuel cells stack weight and volume over 50%. The challenge is the metal plate corrosion protection at low cost for the broad commercial applications. This project is aimed to develop innovative technological solutions to overcome the corrosion barrier of low cost metal plates. The feasibility of has been demonstrated and patented (US Patent 7,309,540). The plan is to further reduce the cost, and scale up the technology. The project is built on three pillars: 1) robust experimental evidence demonstrating the feasibility of our technology, 2) a team that consists of industrial leaders in fuel cell stack application, design, and manufactures; 3) a low-risk, significant-milestone driven program that proves the feasibility of meeting program objectives The implementation of this project will reduce the fuel cell stack metal bipolar separator plate cost which accounts 15-21% of the overall stack cost. It will contribute to the market adoption of fuel cell technologies. In addition, this corrosion protection technology can be used similar energy devices, such as batteries and electrolyzers. Therefore, the success of the project will be benefit in broad markets.

  20. Fuel cell repeater unit including frame and separator plate

    Energy Technology Data Exchange (ETDEWEB)

    Yamanis, Jean; Hawkes, Justin R; Chiapetta, Jr., Louis; Bird, Connie E; Sun, Ellen Y; Croteau, Paul F

    2013-11-05

    An example fuel cell repeater includes a separator plate and a frame establishing at least a portion of a flow path that is operative to communicate fuel to or from at least one fuel cell held by the frame relative to the separator plate. The flow path has a perimeter and any fuel within the perimeter flow across the at least one fuel cell in a first direction. The separator plate, the frame, or both establish at least one conduit positioned outside the flow path perimeter. The conduit is outside of the flow path perimeter and is configured to direct flow in a second, different direction. The conduit is fluidly coupled with the flow path.

  1. Microfabrication of Microchannels for Fuel Cell Plates

    OpenAIRE

    Ho Su Jang; Dong Sam Park

    2009-01-01

    Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of m...

  2. Next Generation Bipolar Plates for Automotive PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Adrianowycz, Orest; Norley, Julian; Stuart, David J; Flaherty, David; Wayne, Ryan; ; Williams, Warren; Tietze, Roger; Nguyen, Yen-Loan H; Zawodzinski, Tom; Pietrasz, Patrick

    2010-04-15

    The results of a successful U.S. Department of Energy (DoE) funded two-year $2.9 MM program lead by GrafTech International Inc. (GrafTech) are reported and summarized. The program goal was to develop the next generation of high temperature proton exchange membrane (PEM) fuel cell bipolar plates for use in transportation fuel cell applications operating at temperatures up to 120 °C. The bipolar plate composite developed during the program is based on GrafTech’s GRAFCELL resin impregnated flexible graphite technology and makes use of a high temperature Huntsman Advanced Materials resin system which extends the upper use temperature of the composite to the DoE target. High temperature performance of the new composite is achieved with the added benefit of improvements in strength, modulus, and dimensional stability over the incumbent resin systems. Other physical properties, including thermal and electrical conductivity of the new composite are identical to or not adversely affected by the new resin system. Using the new bipolar plate composite system, machined plates were fabricated and tested in high temperature single-cell fuel cells operating at 120 °C for over 1100 hours by Case Western Reserve University. Final verification of performance was done on embossed full-size plates which were fabricated and glued into bipolar plates by GrafTech. Stack testing was done on a 10-cell full-sized stack under a simulated drive cycle protocol by Ballard Power Systems. Freeze-thaw performance was conducted by Ballard on a separate 5-cell stack and shown to be within specification. A third stack was assembled and shipped to Argonne National Laboratory for independent performance verification. Manufacturing cost estimate for the production of the new bipolar plate composite at current and high volume production scenarios was performed by Directed Technologies Inc. (DTI). The production cost estimates were consistent with previous DoE cost estimates performed by DTI for the

  3. Microfabrication of microchannels for fuel cell plates.

    Science.gov (United States)

    Jang, Ho Su; Park, Dong Sam

    2010-01-01

    Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of microchannel technology. In this study, the conventional method of chemical etching and the mechanical machining method of micro end milling were used for the microfabrication of microchannel for fuel cell separators. The two methods were compared in terms of their performance in the fabrication with regards to dimensional errors, flatness, straightness, and surface roughness. Following microchannel fabrication, the powder blasting technique is introduced to improve the coating performance of the catalyst on the surface of the microchannel. Experimental results show that end milling can remarkably increase the fabrication performance and that surface treatment by powder blasting can improve the performance of catalyst coating.

  4. Microfabrication of Microchannels for Fuel Cell Plates

    Directory of Open Access Journals (Sweden)

    Ho Su Jang

    2009-12-01

    Full Text Available Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of microchannel technology. In this study, the conventional method of chemical etching and the mechanical machining method of micro end milling were used for the microfabrication of microchannel for fuel cell separators. The two methods were compared in terms of their performance in the fabrication with regards to dimensional errors, flatness, straightness, and surface roughness. Following microchannel fabrication, the powder blasting technique is introduced to improve the coating performance of the catalyst on the surface of the microchannel. Experimental results show that end milling can remarkably increase the fabrication performance and that surface treatment by powder blasting can improve the performance of catalyst coating.

  5. Development of a selective agar plate for the detection of Campylobacter spp. in fresh produce.

    Science.gov (United States)

    Yoo, Jin-Hee; Choi, Na-Young; Bae, Young-Min; Lee, Jung-Su; Lee, Sun-Young

    2014-10-17

    This study was conducted to develop a selective medium for the detection of Campylobacter spp. in fresh produce. Campylobacter spp. (n=4), non-Campylobacter (showing positive results on Campylobacter selective agar) strains (n=49) isolated from fresh produce, indicator bacteria (n=13), and spoilage bacteria isolated from fresh produce (n=15) were plated on four Campylobacter selective media. Bolton agar and modified charcoal cefoperazone deoxycholate agar (mCCDA) exhibited higher sensitivity for Campylobacter spp. than did Preston agar and Hunt agar, although certain non-Campylobacter strains isolated from fresh produce by using a selective agar isolation method, were still able to grow on Bolton agar and mCCDA. To inhibit the growth of non-Campylobacter strains, Bolton agar and mCCDA were supplemented with 5 antibiotics (rifampicin, polymyxin B, sodium metabisulfite, sodium pyruvate, ferrous sulfate) and the growth of Campylobacter spp. (n=7) and non-Campylobacter strains (n=44) was evaluated. Although Bolton agar supplemented with rifampicin (BR agar) exhibited a higher selectivity for Campylobacter spp. than did mCCDA supplemented with antibiotics, certain non-Campylobacter strains were still able to grow on BR agar (18.8%). When BR agar with various concentrations of sulfamethoxazole-trimethoprim were tested with Campylobacter spp. (n=8) and non-Campylobacter (n=7), sulfamethoxazole-trimethoprim was inhibitory against 3 of 7 non-Campylobacter strains. Finally, we validated the use of BR agar containing 50mg/L sulfamethoxazole (BRS agar) or 0.5mg/L ciprofloxacin (BRCS agar) and other selective agars for the detection of Campylobacter spp. in chicken and fresh produce. All chicken samples were positive for Campylobacter spp. when tested on mCCDA, BR agar, and BRS agar. In fresh produce samples, BRS agar exhibited the highest selectivity for Campylobacter spp., demonstrating its suitability for the detection of Campylobacter spp. in fresh produce.

  6. Growth and Plating of Cell Suspension Cultures of Datura Innoxia

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1974-01-01

    Suspension cultures of Datura innoxia Mill, were successfully grown on a modified Murashige and Skoog medium with 2,4–D, NAA or BAP as growth substances, provided the micronutrient levels were reduced to 1/10. Normal amounts of micronutrients were toxic. Attempts to identify the toxic elements did...... malate) or on NO3−-N alone. Dry weight yield was proportional to the amount of nitrate-N added (47 mg/mg N). Filtered suspension cultures containing single cells (plating cultures) could be grown in agar in petri dishes when NAA or 2,4-D were used as growth substances. Cells grew at densities above 500...... units/ml in the agar. Most colonies grew from cell aggregates but division in single cells was observed. The highest plating efficiency was about 50% on 10−6 M 2,4-D + 1 g/1 casein hydrolysate....

  7. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    ’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through......Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty...... the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature...

  8. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty......’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through...... the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature...

  9. Performance evaluation and characterization of metallic bipolar plates in a proton exchange membrane (PEM) fuel cell

    Science.gov (United States)

    Hung, Yue

    Bipolar plate and membrane electrode assembly (MEA) are the two most repeated components of a proton exchange membrane (PEM) fuel cell stack. Bipolar plates comprise more than 60% of the weight and account for 30% of the total cost of a fuel cell stack. The bipolar plates perform as current conductors between cells, provide conduits for reactant gases, facilitate water and thermal management through the cell, and constitute the backbone of a power stack. In addition, bipolar plates must have excellent corrosion resistance to withstand the highly corrosive environment inside the fuel cell, and they must maintain low interfacial contact resistance throughout the operation to achieve optimum power density output. Currently, commercial bipolar plates are made of graphite composites because of their relatively low interfacial contact resistance (ICR) and high corrosion resistance. However, graphite composite's manufacturability, permeability, and durability for shock and vibration are unfavorable in comparison to metals. Therefore, metals have been considered as a replacement material for graphite composite bipolar plates. Since bipolar plates must possess the combined advantages of both metals and graphite composites in the fuel cell technology, various methods and techniques are being developed to combat metallic corrosion and eliminate the passive layer formed on the metal surface that causes unacceptable power reduction and possible fouling of the catalyst and the electrolyte. The main objective of this study was to explore the possibility of producing efficient, cost-effective and durable metallic bipolar plates that were capable of functioning in the highly corrosive fuel cell environment. Bulk materials such as Poco graphite, graphite composite, SS310, SS316, incoloy 800, titanium carbide and zirconium carbide were investigated as potential bipolar plate materials. In this work, different alloys and compositions of chromium carbide coatings on aluminum and SS316

  10. Cells and methods for producing fatty alcohols

    Science.gov (United States)

    Pfleger, Brian F.; Youngquist, Tyler J.

    2017-07-18

    Recombinant cells and methods for improved yield of fatty alcohols. The recombinant cells harbor a recombinant thioesterase gene, a recombinant acyl-CoA synthetase gene, and a recombinant acyl-CoA reductase gene. In addition, a gene product from one or more of an acyl-CoA dehydrogenase gene, an enoyl-CoA hydratase gene, a 3-hydroxyacyl-CoA dehydrogenase gene, and a 3-ketoacyl-CoA thiolase gene in the recombinant cells is functionally deleted. Culturing the recombinant cells produces fatty alcohols at high yields.

  11. A novel cell subset:Interferon-producing killer dendritic cells

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Recent reports introduce a novel cell subset of DCs with antigenic phenotypes shared by both NK cells and B cells, but without surface markers of pDCs and T cells, appearing to be a chimera of NK cells and DCs, namely interferon-producing killer dendritic cells(IKDCs).IKDCs not only secret type I and type II interferons to recognize and kill tumor cells effectively, but also express MHC-II molecules to present antigens.Thus, IKDCs are considered as important immunosurveilance cells for tumors, providing a link between innate and adaptive immunity.

  12. Quantitative analysis of changes in actin microfilament contribution to cell plate development in plant cytokinesis

    Directory of Open Access Journals (Sweden)

    Sano Toshio

    2008-07-01

    Full Text Available Abstract Background Plant cells divide by the formation of new cross walls, known as cell plates, from the center to periphery of each dividing cell. Formation of the cell plate occurs in the phragmoplast, a complex structure composed of membranes, microtubules (MTs and actin microfilaments (MFs. Disruption of phragmoplast MTs was previously found to completely inhibit cell plate formation and expansion, indicative of their crucial role in the transport of cell plate membranes and materials. In contrast, disruption of MFs only delays cell plate expansion but does not completely inhibit cell plate formation. Despite such findings, the significance and molecular mechanisms of MTs and MFs remain largely unknown. Results Time-sequential changes in MF-distribution were monitored by live imaging of tobacco BY-2 cells stably expressing the GFP-actin binding domain 2 (GFP-ABD2 fusion protein, which vitally co-stained with the endocytic tracer, FM4-64, that labels the cell plate. During cytokinesis, MFs accumulated near the newly-separated daughter nuclei towards the emerging cell plate, and subsequently approached the expanding cell plate edges. Treatment with an actin polymerization inhibitor caused a decrease in the cell plate expansion rate, which was quantified using time-lapse imaging and regression analysis. Our results demonstrated time-sequential changes in the contribution of MFs to cell plate expansion; MF-disruption caused about a 10% decrease in the cell plate expansion rate at the early phase of cytokinesis, but about 25% at the late phase. MF-disruption also caused malformation of the emerging cell plate at the early phase, indicative of MF involvement in early cell plate formation and expansion. The dynamic movement of endosomes around the cell plate was also inhibited by treatment with an actin polymerization inhibitor and a myosin ATPase inhibitor, respectively. Furthermore, time-lapse imaging of the endoplasmic reticulum (ER revealed

  13. Osteogenic Cells Derived From Embryonic Stem Cells Produced Bone Nodules in Three-Dimensional Scaffolds

    Directory of Open Access Journals (Sweden)

    Chaudhry G. R.

    2004-01-01

    Full Text Available An approach for 3D bone tissue generation from embryonic stem (ES cells was investigated. The ES cells were induced to differentiate into osteogenic precursors, capable of proliferating and subsequently differentiating into bone-forming cells. The differentiated cells and the seeded scaffolds were characterized using von Kossa and Alizarin Red staining, electron microscopy, and RT-PCR analysis. The results demonstrated that ES-derived bone-forming cells attached to and colonized the biocompatible and biodegradable scaffolds. Furthermore, these cells produced bone nodules when grown for 3–4 weeks in mineralization medium containing ascorbic acid and beta-glycerophosphate both in tissue culture plates and in scaffolds. The differentiated cells also expressed osteospecific markers when grown both in the culture plates and in 3D scaffolds. Osteogenic cells expressed alkaline phosphatase, osteocalcin, and osteopontin, but not an ES cell-specific marker, oct-4. These findings suggest that ES cell can be used for in vitro tissue engineering and cultivation of graftable skeletal structures.

  14. Plate screening methods for the detection of polysaccharase-producing microorganisms

    NARCIS (Netherlands)

    Ruijssenaars, H.J.; Hartmans, S.

    2000-01-01

    Polysaccharide-degrading enzymes (polysaccharases) are widely applied in industry. One of the sources of these enzymes are polysaccharide-degrading microorganisms. To obtain such microorganisms from enrichment cultures, strain collections or gene libraries, efficient plate screening methods are requ

  15. Mass production of spores of lactic acid-producing Rhizopus oryzae NBRC 5384 on agar plate.

    Science.gov (United States)

    Yamane, Tsuneo; Tanaka, Ryosuke

    2013-01-01

    Mass production of sporangiospores (spores) of Rhizopus oryzae NBRC 5384 (identical to NRRL 395 and ATCC 9363) on potato-dextrose-agar medium was studied aiming at starting its L(+)-lactic acid fermentation directly from spore inoculation. Various parameters including harvest time, sowed spore density, size of agar plate, height of air space, and incubation mode of plate (agar-on-bottom or agar-on-top) were studied. Ordinarily used shallow Petri dishes were found out to be unsuitable for the full growth of R. oryzae sporangiophores. In a very wide range of the sowed spore density, the smaller it was, the greater the number of the harvested spores was. It was also interesting to find out that R. oryzae grown downward vertically with a deep air space in an agar-on-top mode gave larger amount of spores than in an agar-on-bottom mode at 30°C for 7-day cultivation. Scale-up of the agar plate culture from 26.4 to 292 cm(2) was studied, resulting in the proportional relationship between the number of the harvested spores/plate and the plate area in the deep Petri dishes. The number of plates of 50 cm in diameter needed for 100 m(3) industrial submerged fermentation started directly from 2 × 10(5) spores/mL inoculum size was estimated as about 6, from which it was inferred that such a fermentation would be feasible. Designing a 50 cm plate and a method of spreading and collecting the spores were suggested. Bioprocess technological significance of the "full-scale industrial submerged fermentation started directly from spore inoculation omitting pre-culture" has been discussed.

  16. Microstructured multi-well plate for three-dimensional packed cell seeding and hepatocyte cell culture.

    Science.gov (United States)

    Goral, Vasiliy N; Au, Sam H; Faris, Ronald A; Yuen, Po Ki

    2014-07-01

    In this article, we present a microstructured multi-well plate for enabling three-dimensional (3D) high density seeding and culture of cells through the use of a standard laboratory centrifuge to promote and maintain 3D tissue-like cellular morphology and cell-specific functionality in vitro without the addition of animal derived or synthetic matrices or coagulants. Each well has microfeatures on the bottom that are comprised of a series of ditches/open microchannels. The dimensions of the microchannels promote and maintain 3D tissue-like cellular morphology and cell-specific functionality in vitro. After cell seeding with a standard pipette, the microstructured multi-well plates were centrifuged to tightly pack cells inside the ditches in order to enhance cell-cell interactions and induce formation of 3D cellular structures during cell culture. Cell-cell interactions were optimized based on cell packing by considering dimensions of the ditches/open microchannels, orientation of the microstructured multi-well plate during centrifugation, cell seeding density, and the centrifugal force and time. With the optimized cell packing conditions, we demonstrated that after 7 days of cell culture, primary human hepatocytes adhered tightly together to form cord-like structures that resembled 3D tissue-like cellular architecture. Importantly, cell membrane polarity was restored without the addition of animal derived or synthetic matrices or coagulants.

  17. Foxj1 regulates floor plate cilia architecture and modifies the response of cells to sonic hedgehog signalling

    Science.gov (United States)

    Cruz, Catarina; Ribes, Vanessa; Kutejova, Eva; Cayuso, Jordi; Lawson, Victoria; Norris, Dominic; Stevens, Jonathan; Davey, Megan; Blight, Ken; Bangs, Fiona; Mynett, Anita; Hirst, Elizabeth; Chung, Rachel; Balaskas, Nikolaos; Brody, Steven L.; Marti, Elisa; Briscoe, James

    2010-01-01

    Sonic hedgehog signalling is essential for the embryonic development of many tissues including the central nervous system, where it controls the pattern of cellular differentiation. A genome-wide screen of neural progenitor cells to evaluate the Shh signalling-regulated transcriptome identified the forkhead transcription factor Foxj1. In both chick and mouse Foxj1 is expressed in the ventral midline of the neural tube in cells that make up the floor plate. Consistent with the role of Foxj1 in the formation of long motile cilia, floor plate cells produce cilia that are longer than the primary cilia found elsewhere in the neural tube, and forced expression of Foxj1 in neuroepithelial cells is sufficient to increase cilia length. In addition, the expression of Foxj1 in the neural tube and in an Shh-responsive cell line attenuates intracellular signalling by decreasing the activity of Gli proteins, the transcriptional mediators of Shh signalling. We show that this function of Foxj1 depends on cilia. Nevertheless, floor plate identity and ciliogenesis are unaffected in mouse embryos lacking Foxj1 and we provide evidence that additional transcription factors expressed in the floor plate share overlapping functions with Foxj1. Together, these findings identify a novel mechanism that modifies the cellular response to Shh signalling and reveal morphological and functional features of the amniote floor plate that distinguish these cells from the rest of the neuroepithelium. PMID:21098568

  18. A rapid, efficient and sensitive plate assay for detection and screening of l-asparaginase-producing microorganisms.

    Science.gov (United States)

    Mahajan, Richi V; Saran, Saurabh; Saxena, Rajendra K; Srivastava, Ayush K

    2013-04-01

    l-Asparaginase-producing microbes are conventionally screened on phenol red l-asparagine-containing plates. However, sometimes the contrast of the zone obtained (between yellow and pink) is not very sharp and distinct. In the present investigation, an improved method for screening of the microorganisms producing extracellular l-asparaginase is reported wherein bromothymol blue (BTB) is incorporated as pH indicator in l-asparagine-containing medium instead of phenol red. Plates containing BTB at acidic pH are yellow and turn dark blue at alkaline pH. Thus, a dense dark blue zone is formed around microbial colonies producing l-asparaginase, differentiating between enzyme producers and non-producers. The present method is more sensitive and accurate than the conventional method for screening of both fungi and bacteria producing extracellular l-asparaginase. Furthermore, BTB gives a transient green colour at neutral pH (7.0) and dark blue colour at higher pH 8.0-9.0, indicating the potency of the microorganism for l-asparaginase production.

  19. Surface modified stainless steels for PEM fuel cell bipolar plates

    Science.gov (United States)

    Brady, Michael P [Oak Ridge, TN; Wang, Heli [Littleton, CO; Turner, John A [Littleton, CO

    2007-07-24

    A nitridation treated stainless steel article (such as a bipolar plate for a proton exchange membrane fuel cell) having lower interfacial contact electrical resistance and better corrosion resistance than an untreated stainless steel article is disclosed. The treated stainless steel article has a surface layer including nitrogen-modified chromium-base oxide and precipitates of chromium nitride formed during nitridation wherein oxygen is present in the surface layer at a greater concentration than nitrogen. The surface layer may further include precipitates of titanium nitride and/or aluminum oxide. The surface layer in the treated article is chemically heterogeneous surface rather than a uniform or semi-uniform surface layer exclusively rich in chromium, titanium or aluminum. The precipitates of titanium nitride and/or aluminum oxide are formed by the nitriding treatment wherein titanium and/or aluminum in the stainless steel are segregated to the surface layer in forms that exhibit a low contact resistance and good corrosion resistance.

  20. Applications of profile filtering in the dimensional metrology of fuel cell plates

    Science.gov (United States)

    Muralikrishnan, Bala; Ren, Wei; Stanfield, Eric; Everett, Dennis; Zheng, Alan; Doiron, Ted

    2013-06-01

    We describe the application of several surface profile filters as an enabling tool in the dimensional measurements of an engineering artifact, namely, a fuel cell plate. We recently reported work on the development of a non-contact system for dimensional metrology of bipolar fuel cell plates. That system comprises two laser spot triangulation probes that acquire profile data across a plate. While the non-contact system provides rapid measurements (measurement speed of 100 mm s-1 to 500 mm s-1), the data are noisy and cannot be used directly to obtain features of interest such as channel depth and width. In this paper, we show how different surface profile filters such as the spline, morphological, and robust filters, can be employed to identify and suppress outliers and to produce a mean line that serves as a substitute geometry from which we can determine features of interest. Further, we compare the non-contact probe data against contact probe measurements made using a coordinate measuring machine. Surface profile filters are again useful in correcting the reference data for tip size and also in removing any free form deformation in both data sets prior to parameter evaluation and comparison.

  1. [Clinical assessment of novel ChromID ESBL agar plates for detection of ESBL producers in the family Enterobacteriaceae].

    Science.gov (United States)

    Kasuga, Eriko; Matsumoto, Takehisa; Hidaka, Eiko; Oguchi, Harumi; Kanai, Shinichiro; Oana, Kozue; Yamauchi, Kazuyoshi; Honda, Takayuki; Kawakami, Yoshiyuki

    2009-01-01

    Extended-Spectrum beta-Lactamase (ESBL)-producers in the family Enterobacteriaceae are recognized worldwide as nosocomial pathogens, however it is difficult to screen them in the routine laboratory processing. ChromID ESBL agar newly developed for screening ESBL-producing Enterobacteriaceae was released in Japan in April, 2007. We evaluated the clinical assessment of ChromID ESBL agar in routine microbiology laboratory. The 47 strains investigated were clinical isolates belonging to the family Enterobacteriaceae with the MICs of cefpodoxime greater than 2 mug/ml. The 27 ESBL-producers examined were comprising of 19 Escherichia coli, 3 Klebsiella oxytoca, 1 Citrobacter freundii, 3 Enterobacter cloacae, and 1 S. marcescens (ESBL group) and 20 ESBL non-producers consiating of 5 K. oxytoca, 1 Proteus mirabilis, 1 P. vlugaris, 2 Serratia marcescens, 8 C. freundii, 2 Enterobacter cloacae, and 1 E. aerogenes (non-ESBL group). Characterization of beta-lactamase genes was carried out by use of polymerase chain reaction. As the results, the sensitivity and the specificity of ChromID ESBL agar plates after incubation for 18 hours was 100% and 20%, respectively. It should be noted that the values of specificity was extremely low compared with those of the sensitivity. These findings clearly suggested that in cases of utilizing ChromID ESBL agar plates, it should be important to consider its characteristic properties, as even the ESBL-non-producers could grow on these media only when they were resistant to CPDX.

  2. Dynamic transcriptional signature and cell fate analysis reveals plasticity of individual neural plate border cells.

    Science.gov (United States)

    Roellig, Daniela; Tan-Cabugao, Johanna; Esaian, Sevan; Bronner, Marianne E

    2017-03-29

    The 'neural plate border' of vertebrate embryos contains precursors of neural crest and placode cells, both defining vertebrate characteristics. How these lineages segregate from neural and epidermal fates has been a matter of debate. We address this by performing a fine-scale quantitative temporal analysis of transcription factor expression in the neural plate border of chick embryos. The results reveal significant overlap of transcription factors characteristic of multiple lineages in individual border cells from gastrula through neurula stages. Cell fate analysis using a Sox2 (neural) enhancer reveals that cells that are initially Sox2+ cells can contribute not only to neural tube but also to neural crest and epidermis. Moreover, modulating levels of Sox2 or Pax7 alters the apportionment of neural tube versus neural crest fates. Our results resolve a long-standing question and suggest that many individual border cells maintain ability to contribute to multiple ectodermal lineages until or beyond neural tube closure.

  3. Influence of the ARC patterning method and annealing on the contact adhesion of Ni/Cu-plated solar cells

    Science.gov (United States)

    Baik, Jong Wook; Lee, Sang Hee; Lee, Doo Won; Lee, Soo Hong

    2016-05-01

    Ni/Cu two-step plating is a promising metallization technique because low contact resistance and improved contact adhesion can be achieved after the Ni annealing process. Also, narrow fingers, which are required for high-efficiency solar cells, can be formed by plating. However, the reliability of contact adhesion is still considered one obstacle to industrializing solar cells with plated metal contacts. In this experiment, the influence of ARC opening methods on plated contact adhesion was investigated because the roughnesses of the Si surfaces produced by using pico-second laser ablation and photolithography may be different. Also, the annealing process was conducted before and after plating Cu/Ag metal stacks. The sequence of the annealing can be significant for efficient production because plating is a wet process while annealing is a dry process. The contact adhesion was measured by using a peel-off test. The test was conducted on a 1.5-mm-wide by a 60 ~ 70- mm-long bus bar area. A 3.2-N/mm adhesion force was recorded as a highest average value along the bus bar.

  4. Development of a soft x-ray plasma camera with a Fresnel zone plate to image laser produced plasmas

    Science.gov (United States)

    Kado, M.; Mori, M.; Nishiuchi, M.; Ishino, M.; Kawachi, T.

    2009-09-01

    A soft x-ray plasma camera operated at 3.35nm in the water window x-ray region is developed and demonstrated imaging gas jet plasmas of several spices produced with a 10TW Ti: sapphire laser. The plasma camera consists of a 300nm thick Ag/Ti/Si3N4 x-ray band pass filter with bandwidth of 1.43nm to cut visible light and also to reduce colour aberration of the Fresnel zone plate, a Fresnel zone plate with diameter of 1mm and outermost zone width of 300nm, and a soft x-ray CCD camera. The magnification of the plasma camera is 10. The soft x-ray plasma camera powered by a Fresnel zone plate is a very powerful tool to observe laser produced plasmas since it is 1000 times brighter and has 5 times higher spatial resolution comparing ordinary x-ray pinhole camera. The soft x-ray images of helium, nitrogen, argon, krypton, and xenon gas jet plasmas are obtained changing gas pressure from 0.01MPa to 1MPa.

  5. Producing primate embryonic stem cells by somatic cell nuclear transfer.

    Science.gov (United States)

    Byrne, J A; Pedersen, D A; Clepper, L L; Nelson, M; Sanger, W G; Gokhale, S; Wolf, D P; Mitalipov, S M

    2007-11-22

    Derivation of embryonic stem (ES) cells genetically identical to a patient by somatic cell nuclear transfer (SCNT) holds the potential to cure or alleviate the symptoms of many degenerative diseases while circumventing concerns regarding rejection by the host immune system. However, the concept has only been achieved in the mouse, whereas inefficient reprogramming and poor embryonic development characterizes the results obtained in primates. Here, we used a modified SCNT approach to produce rhesus macaque blastocysts from adult skin fibroblasts, and successfully isolated two ES cell lines from these embryos. DNA analysis confirmed that nuclear DNA was identical to donor somatic cells and that mitochondrial DNA originated from oocytes. Both cell lines exhibited normal ES cell morphology, expressed key stem-cell markers, were transcriptionally similar to control ES cells and differentiated into multiple cell types in vitro and in vivo. Our results represent successful nuclear reprogramming of adult somatic cells into pluripotent ES cells and demonstrate proof-of-concept for therapeutic cloning in primates.

  6. Thermal modeling and the optimized design of metal plate cooling systems for single concentrator solar cells

    Institute of Scientific and Technical Information of China (English)

    Cui Min; Chen Nuo-Fu; Deng Jin-Xiang

    2012-01-01

    A metal plate cooling model for 400× single concentrator solar cells was established.The effects of the thickness and the radius of the metal plate,and the air environment on the temperature of the solar cells were analyzed in detail.It is shown that the temperature of the solar cells decreased sharply at the beginning,with the increase in the thickness of the metal plate,and then changed more smoothly.When the radius of the metal plate was 4 cm and the thickness increased to 2 mm or thicker,the temperature of the solar cell basically stabilized at about 53 ℃.Increasing the radius of the metal plate and the convective transfer coefficient made the temperature of the solar cell decrease remarkably.The effects of A1 and Cu as the metal plate material on cooling were analyzed contrastively,and demonstrated the superiority of Al material for the cooling system.Furthermore,considering cost reduction,space holding and the stress of the system,we optimized the structural design of the metal plate.The simulated results can be referred to the design of the structure for the metal plate.Finally,a method to devise the structure of the metal plate for single concentrator solar cells was given.

  7. Bioreactor and methods for producing synchronous cells

    Science.gov (United States)

    Helmstetter, Charles E. (Inventor); Thornton, Maureen (Inventor); Gonda, Steve (Inventor)

    2005-01-01

    Apparatus and methods are directed to a perfusion culture system in which a rotating bioreactor is used to grow cells in a liquid culture medium, while these cells are attached to an adhesive-treated porous surface. As a result of this arrangement and its rotation, the attached cells divide, with one cell remaining attached to the substrate, while the other cell, a newborn cell is released. These newborn cells are of approximately the same age, that are collected upon leaving the bioreactor. The populations of newborn cells collected are of synchronous and are minimally, if at all, disturbed metabolically.

  8. Design and simulation of novel flow field plate geometry for proton exchange membrane fuel cells

    Science.gov (United States)

    Ruan, Hanxia; Wu, Chaoqun; Liu, Shuliang; Chen, Tao

    2016-10-01

    Bipolar plate is one of the many important components of proton exchange membrane fuel cell (PEMFC) stacks as it supplies fuel and oxidant to the membrane-electrode assembly (MEA), removes water, collects produced current and provides mechanical support for the single cells in the stack. The flow field design of a bipolar plate greatly affects the performance of a PEMFC. It must uniformly distribute the reactant gases over the MEA and prevent product water flooding. This paper aims at improving the fuel cell performance by optimizing flow field designs and flow channel configurations. To achieve this, a novel biomimetic flow channel for flow field designs is proposed based on Murray's Law. Computational fluid dynamics based simulations were performed to compare three different designs (parallel, serpentine and biomimetic channel, respectively) in terms of current density distribution, power density distribution, pressure distribution, temperature distribution, and hydrogen mass fraction distribution. It was found that flow field designs with biomimetic flow channel perform better than that with convectional flow channel under the same operating conditions.

  9. Development of the nanotiter plate for use in antibody and cell array technologies

    Science.gov (United States)

    Ramdutt, Devin; Lui, Rodney; Davies, Kerrie; Boswell, Rod W.; dos Remedios, Cristobal G.; Charles, Christine; Bilek, Marcela M.; McKenzie, David R.

    2005-02-01

    The design and fabrication of biomedical tools using techniques common in microelectronics is becoming established procedure. In our research, we use gaseous plasma dry etching to form microstructures on silicon wafers. These are intended for use in capturing and binding antibodies and live cells in an array to be used in High Throughput Screening (HTS) and High Content Screening (HCS) of new pharmaceuticals. We call this new arraying plate the "Nanotiter" plate. The benefit of our design (100 x 100 wells in a 25 x 25 mm array) over current 96-, 384- and 1056-well microtiter plates are that the number of samples (wells) that can be tested in one plate scan can be substantially increased, the wells can be rapidly and effectively washed, and the well surfaces can be modified to modulate ligand binding. Simple crowding of wells on a plate can result in cross contamination of samples in adjacent wells during the washing. Furthermore, motile cells may migrate between the wells. 1056 microtiter plates currently cannot be washed, and washing 384 plates is problematic. Our design incorporates plasma-deposited polymers that functionally bind antibodies (or other proteins) in but not between wells. Furthermore, the wells can be shaped to minimize cell migration. Inverting the plate on a wash solution allows unbound cells to simply fall away under gravity thus minimising the contamination of adjacent wells. Thus, our Nanotiter plate represents a substantial improvement over existing technology.

  10. Multipotent Mesenchymal Stromal Stem Cell Expansion by Plating Whole Bone Marrow at a Low Cellular Density: A More Advantageous Method for Clinical Use

    Science.gov (United States)

    Mareschi, Katia; Rustichelli, Deborah; Calabrese, Roberto; Gunetti, Monica; Sanavio, Fiorella; Castiglia, Sara; Risso, Alessandra; Ferrero, Ivana; Tarella, Corrado; Fagioli, Franca

    2012-01-01

    Mesenchymal stem cells (MSCs) are a promising source for cell therapy due to their pluripotency and immunomodulant proprieties. As the identification of “optimal” conditions is important to identify a standard procedure for clinical use. Percoll, Ficoll and whole bone marrow directly plated were tested from the same sample as separation methods. The cells were seeded at the following densities: 100 000, 10 000, 1000, 100, 10 cells/cm2. After reaching confluence, the cells were detached, pooled and re-plated at 1000, 500, 100, and 10 cells/cm2. Statistical analyses were performed. Cumulative Population Doublings (PD) did not show significant differences for the separation methods and seeding densities but only for the plating density. Some small quantity samples plated in T25 flasks at plating densities of 10 and 100 cells/cm2 did not produce any expansion. However, directly plated whole bone marrow resulted in a more advantageous method in terms of CFU-F number, cellular growth and minimal manipulation. No differences were observed in terms of gross morphology, differentiation potential or immunophenotype. These data suggest that plating whole bone marrow at a low cellular density may represent a good procedure for MSC expansion for clinical use. PMID:23715383

  11. Multipotent Mesenchymal Stromal Stem Cell Expansion by Plating Whole Bone Marrow at a Low Cellular Density: A More Advantageous Method for Clinical Use

    Directory of Open Access Journals (Sweden)

    Katia Mareschi

    2012-01-01

    Full Text Available Mesenchymal stem cells (MSCs are a promising source for cell therapy due to their pluripotency and immunomodulant proprieties. As the identification of “optimal” conditions is important to identify a standard procedure for clinical use. Percoll, Ficoll and whole bone marrow directly plated were tested from the same sample as separation methods. The cells were seeded at the following densities: 100 000, 10 000, 1000, 100, 10 cells/cm2. After reaching confluence, the cells were detached, pooled and re-plated at 1000, 500, 100, and 10 cells/cm2. Statistical analyses were performed. Cumulative Population Doublings (PD did not show significant differences for the separation methods and seeding densities but only for the plating density. Some small quantity samples plated in T25 flasks at plating densities of 10 and 100 cells/cm2 did not produce any expansion. However, directly plated whole bone marrow resulted in a more advantageous method in terms of CFU-F number, cellular growth and minimal manipulation. No differences were observed in terms of gross morphology, differentiation potential or immunophenotype. These data suggest that plating whole bone marrow at a low cellular density may represent a good procedure for MSC expansion for clinical use.

  12. Laminated exfoliated graphite composite-metal compositions for fuel cell flow field plate or bipolar plate applications

    Science.gov (United States)

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-05-20

    An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the first exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

  13. Corrosion-resistant, electrically-conductive plate for use in a fuel cell stack

    Science.gov (United States)

    Carter, J David [Bolingbrook, IL; Mawdsley, Jennifer R [Woodridge, IL; Niyogi, Suhas [Woodridge, IL; Wang, Xiaoping [Naperville, IL; Cruse, Terry [Lisle, IL; Santos, Lilia [Lombard, IL

    2010-04-20

    A corrosion resistant, electrically-conductive, durable plate at least partially coated with an anchor coating and a corrosion resistant coating. The corrosion resistant coating made of at least a polymer and a plurality of corrosion resistant particles each having a surface area between about 1-20 m.sup.2/g and a diameter less than about 10 microns. Preferably, the plate is used as a bipolar plate in a proton exchange membrane (PEMFC) fuel cell stack.

  14. Pre-oxidized and nitrided stainless steel alloy foil for proton exchange membrane fuel cell bipolar plates. Part 2: Single-cell fuel cell evaluation of stamped plates

    Science.gov (United States)

    Toops, Todd J.; Brady, Michael P.; Tortorelli, Peter F.; Pihl, Josh A.; Estevez, Francisco; Connors, Daniel; Garzon, Fernando; Rockward, Tommy; Gervasio, Don; Mylan, William; Kosaraju, Sree Harsha

    Thermal (gas) nitridation of stainless steel alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr 2N, CrN, TiN, V 2N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of proton exchange membrane (PEM) single-cell fuel cell studies of stamped and pre-oxidized/nitrided developmental Fe-20Cr-4V weight percent (wt.%) and commercial type 2205 stainless steel alloy foils. The single-cell fuel cell behavior of the stamped and pre-oxidized/nitrided material was compared to as-stamped (no surface treatment) 904L, 2205, and Fe-20Cr-4V stainless steel alloy foils and machined graphite of similar flow field design. The best fuel cell behavior among the alloys was exhibited by the pre-oxidized/nitrided Fe-20Cr-4V, which exhibited ∼5-20% better peak power output than untreated Fe-20Cr-4V, 2205, and 904L metal stampings. Durability was assessed for pre-oxidized/nitrided Fe-20Cr-4V, 904L metal, and graphite plates by 1000+ h of cyclic single-cell fuel cell testing. All three materials showed good durability with no significant degradation in cell power output. Post-test analysis indicated no metal ion contamination of the membrane electrode assemblies (MEAs) occurred with the pre-oxidized and nitrided Fe-20Cr-4V or graphite plates, and only a minor amount of contamination with the 904L plates.

  15. Effects of plating density and culture time on bone marrow stromal cell characteristics.

    Science.gov (United States)

    Neuhuber, Birgit; Swanger, Sharon A; Howard, Linda; Mackay, Alastair; Fischer, Itzhak

    2008-09-01

    Bone marrow stromal cells (MSC) are multipotent adult stem cells that have emerged as promising candidates for cell therapy in disorders including cardiac infarction, stroke, and spinal cord injury. While harvesting methods used by different laboratories are relatively standard, MSC culturing protocols vary widely. This study is aimed at evaluating the effects of initial plating density and total time in culture on proliferation, cell morphology, and differentiation potential of heterogeneous MSC cultures and more homogeneous cloned subpopulations. Rat MSC were plated at 20, 200, and 2000 cells/cm(2) and grown to 50% confluency. The numbers of population doublings and doubling times were determined within and across multiple passages. Changes in cell morphology and differentiation potential to adipogenic, chondrogenic, and osteogenic lineages were evaluated and compared among early, intermediate, and late passages, as well as between heterogeneous and cloned MSC populations. We found optimal cell growth at a plating density of 200 cells/cm(2). Cultures derived from all plating densities developed increased proportions of flat cells over time. Assays for chondrogenesis, osteogenesis, and adipogenesis showed that heterogeneous MSC plated at all densities sustained the potential for all three mesenchymal phenotypes through at least passage 5; the flat subpopulation lost adipogenic and chondrogenic potential. Our findings suggest that the initial plating density is not critical for maintaining a well-defined, multipotent MSC population. Time in culture, however, affects cell characteristics, suggesting that cell expansion should be limited, especially until the specific characteristics of different MSC subpopulations are better understood.

  16. An Assessment of Cell Culture Plate Surface Chemistry for in Vitro Studies of Tissue Engineering Scaffolds

    Directory of Open Access Journals (Sweden)

    Alexander Röder

    2015-11-01

    Full Text Available The use of biopolymers as a three dimensional (3D support structure for cell growth is a leading tissue engineering approach in regenerative medicine. Achieving consistent cell seeding and uniform cell distribution throughout 3D scaffold culture in vitro is an ongoing challenge. Traditionally, 3D scaffolds are cultured within tissue culture plates to enable reproducible cell seeding and ease of culture media change. In this study, we compared two different well-plates with different surface properties to assess whether seeding efficiencies and cell growth on 3D scaffolds were affected. Cell attachment and growth of murine calvarial osteoblast (MC3T3-E1 cells within a melt-electrospun poly-ε-caprolactone scaffold were assessed when cultured in either “low-adhesive” non-treated or corona discharged-treated well-plates. Increased cell adhesion was observed on the scaffold placed in the surface treated culture plates compared to the scaffold in the non-treated plates 24 h after seeding, although it was not significant. However, higher cell metabolic activity was observed on the bases of all well-plates than on the scaffold, except for day 21, well metabolic activity was higher in the scaffold contained in non-treated plate than the base. These results indicate that there is no advantage in using non-treated plates to improve initial cell seeding in 3D polymeric tissue engineering scaffolds, however non-treated plates may provide an improved metabolic environment for long-term studies.

  17. The Cell Cycle: An Activity Using Paper Plates to Represent Time Spent in Phases of the Cell Cycle

    Science.gov (United States)

    Scherer, Yvette D.

    2014-01-01

    In this activity, students are given the opportunity to combine skills in math and geometry for a biology lesson in the cell cycle. Students utilize the data they collect and analyze from an online onion-root-tip activity to create a paper-plate time clock representing a 24-hour cell cycle. By dividing the paper plate into appropriate phases of…

  18. The Cell Cycle: An Activity Using Paper Plates to Represent Time Spent in Phases of the Cell Cycle

    Science.gov (United States)

    Scherer, Yvette D.

    2014-01-01

    In this activity, students are given the opportunity to combine skills in math and geometry for a biology lesson in the cell cycle. Students utilize the data they collect and analyze from an online onion-root-tip activity to create a paper-plate time clock representing a 24-hour cell cycle. By dividing the paper plate into appropriate phases of…

  19. Dynamics and roles of phragmoplast microfilaments in cell plate formation during cytokinesis of tobacco BY-2 cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan; ZHANG WenJie; BALUSKA Frantisek; MENZEL Diedrik; REN HaiYun

    2009-01-01

    The phragmoplast is a special apparatus that functions in establishing a cell plate in dividing plant cells.It is known that microfilaments (MFs) are involved in constituting phragmoplast structure, but the dynamic distribution and role of phragmoplast MFs are far from being understood. In this study, the precise structure and dynamics of MFs during the initiation and the late lateral expansion of the phragmoplast were observed by using a tobacco BY-2 cell line stably expressing the microfilament reporter construct GFP-f ABD2. Three-dimensional imaging showed that the phragmoplast MFs were initiated by two populations of MFs emerging between the reconstituting daughter nuclei at anaphase, which migrated to the mid-zone and gave rise to two layers of microfilament arrays. FM4-64 stained vesicles accumulated and fused with the cell plate between the two populations of MFs. The two layers of microfilament arrays of phragmoplast with ends overlapped always surrounded the centrifugally expanding cell plate. Partial disruption of MFs at metaphase by low concentration of latrunculin B resulted in the inhibition of the cell plate consolidation and the blockage of cell plate lateral expansion,whereas high concentration of latrunculin B restrained the progression of the cell cycle. Treating the cell after the initiation of phragmoplast led to the cease of the expansion of the cell plate. Our observations provide new insights into the precise structure and dynamics of phragmoplast MFs during cytokinesis and suggest that dynamic phragmoplast MFs are important in cell plate formation.

  20. Spatio-temporal analysis of cellulose synthesis during cell plate formation in Arabidopsis.

    Science.gov (United States)

    Miart, Fabien; Desprez, Thierry; Biot, Eric; Morin, Halima; Belcram, Katia; Höfte, Herman; Gonneau, Martine; Vernhettes, Samantha

    2014-01-01

    During cytokinesis a new crosswall is rapidly laid down. This process involves the formation at the cell equator of a tubulo-vesicular membrane network (TVN). This TVN evolves into a tubular network (TN) and a planar fenestrated sheet, which extends at its periphery before fusing to the mother cell wall. The role of cell wall polymers in cell plate assembly is poorly understood. We used specific stains and GFP-labelled cellulose synthases (CESAs) to show that cellulose, as well as three distinct CESAs, accumulated in the cell plate already at the TVN stage. This early presence suggests that cellulose is extruded into the tubular membrane structures of the TVN. Co-localisation studies using GFP-CESAs suggest the delivery of cellulose synthase complexes (CSCs) to the cell plate via phragmoplast-associated vesicles. In the more mature TN part of the cell plate, we observed delivery of GFP-CESA from doughnut-shaped organelles, presumably Golgi bodies. During the conversion of the TN into a planar fenestrated sheet, the GFP-CESA density diminished, whereas GFP-CESA levels remained high in the TVN zone at the periphery of the expanding cell plate. We observed retrieval of GFP-CESA in clathrin-containing structures from the central zone of the cell plate and from the plasma membrane of the mother cell, which may contribute to the recycling of CESAs to the peripheral growth zone of the cell plate. These observations, together with mutant phenotypes of cellulose-deficient mutants and pharmacological experiments, suggest a key role for cellulose synthesis already at early stages of cell plate assembly.

  1. A graphite-coated carbon fiber epoxy composite bipolar plate for polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Yu, Ha Na; Lim, Jun Woo; Suh, Jung Do; Lee, Dai Gil

    A PEMFC (polymer electrolyte membrane fuel cell or proton exchange membrane fuel cell) stack is composed of GDLs (gas diffusion layers), MEAs (membrane electrode assemblies), and bipolar plates. One of the important functions of bipolar plates is to collect and conduct the current from cell to cell, which requires low electrical bulk and interfacial resistances. For a carbon fiber epoxy composite bipolar plate, the interfacial resistance is usually much larger than the bulk resistance due to the resin-rich layer on the composite surface. In this study, a thin graphite layer is coated on the carbon/epoxy composite bipolar plate to decrease the interfacial contact resistance between the bipolar plate and the GDL. The total electrical resistance in the through-thickness direction of the bipolar plate is measured with respect to the thickness of the graphite coating layer, and the ratio of the bulk resistance to the interfacial contact resistance is estimated using the measured data. From the experiment, it is found that the graphite coating on the carbon/epoxy composite bipolar plate has 10% and 4% of the total electrical and interfacial contact resistances of the conventional carbon/epoxy composite bipolar plate, respectively, when the graphite coating thickness is 50 μm.

  2. Bipolar plate materials in molten carbonate fuel cells. Final CRADA report.

    Energy Technology Data Exchange (ETDEWEB)

    Krumpelt, M.

    2004-06-01

    Advantages of implementation of power plants based on electrochemical reactions are successfully demonstrated in the USA and Japan. One of the msot promising types of fuel cells (FC) is a type of high temperature fuel cells. At present, thanks to the efforts of the leading countries that develop fuel cell technologies power plants on the basis of molten carbonate fuel cells (MCFC) and solid oxide fuel cells (SOFC) are really close to commercialization. One of the problems that are to be solved for practical implementation of MCFC and SOFC is a problem of corrosion of metal components of stacks that are assembled of a number of fuel cells. One of the major components of MCFC and SOFC stacks is a bipolar separator plate (BSP) that performs several functions - it is separation of reactant gas flows sealing of the joints between fuel cells, and current collection from the surface of electrodes. The goal of Task 1 of the project is to develop new cost-effective nickel coatings for the Russian 20X23H18 steel for an MCFC bipolar separator plate using technological processes usually implemented to apply corrosion stable coatings onto the metal parts for products in the defense. There was planned the research on production of nickel coatings using different methods, first of all the galvanic one and the explosion cladding one. As a result of the works, 0.4 x 712 x 1296 mm plates coated with nickel on one side were to be made and passed to ANL. A line of 4 galvanic baths 600 liters was to be built for the galvanic coating applications. The goal of Task 2 of the project is the development of a new material of an MCFC bipolar separator plate with an upgraded corrosion stability, and development of a technology to produce cold roll sheets of this material the sizes of which will be 0.8 x 712x 1296 mm. As a result of these works, a pilot batch of the rolled material in sheets 0.8 x 712 x 1296 mm in size is to be made (in accordance with the norms and standards of the Russian

  3. Advanced Composite Bipolar Plate for Unitized Regenerative Fuel Cell/Electrolyzer Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of an advanced composite bipolar plate is proposed for a unitized regenerative fuel cell and electrolyzer system that operates on pure feed streams...

  4. Composition of Mineral Produced by Dental Mesenchymal Stem Cells.

    Science.gov (United States)

    Volponi, A A; Gentleman, E; Fatscher, R; Pang, Y W Y; Gentleman, M M; Sharpe, P T

    2015-11-01

    Mesenchymal stem cells isolated from different dental tissues have been described to have osteogenic/odontogenic-like differentiation capacity, but little attention has been paid to the biochemical composition of the material that each produces. Here, we used Raman spectroscopy to analyze the mineralized materials produced in vitro by different dental cell populations, and we compared them with the biochemical composition of native dental tissues. We show that different dental stem cell populations produce materials that differ in their mineral and matrix composition and that these differ from those of native dental tissues. In vitro, BCMP (bone chip mass population), SCAP (stem cells from apical papilla), and SHED (stem cells from human-exfoliated deciduous teeth) cells produce a more highly mineralized matrix when compared with that produced by PDL (periodontal ligament), DPA (dental pulp adult), and GF (gingival fibroblast) cells. Principal component analyses of Raman spectra further demonstrated that the crystallinity and carbonate substitution environments in the material produced by each cell type varied, with DPA cells, for example, producing a more carbonate-substituted mineral and with SCAP, SHED, and GF cells creating a less crystalline material when compared with other dental stem cells and native tissues. These variations in mineral composition reveal intrinsic differences in the various cell populations, which may in turn affect their specific clinical applications.

  5. Dynamic transcriptional signature and cell fate analysis reveals plasticity of individual neural plate border cells

    Science.gov (United States)

    Roellig, Daniela; Tan-Cabugao, Johanna; Esaian, Sevan; Bronner, Marianne E

    2017-01-01

    The ‘neural plate border’ of vertebrate embryos contains precursors of neural crest and placode cells, both defining vertebrate characteristics. How these lineages segregate from neural and epidermal fates has been a matter of debate. We address this by performing a fine-scale quantitative temporal analysis of transcription factor expression in the neural plate border of chick embryos. The results reveal significant overlap of transcription factors characteristic of multiple lineages in individual border cells from gastrula through neurula stages. Cell fate analysis using a Sox2 (neural) enhancer reveals that cells that are initially Sox2+ cells can contribute not only to neural tube but also to neural crest and epidermis. Moreover, modulating levels of Sox2 or Pax7 alters the apportionment of neural tube versus neural crest fates. Our results resolve a long-standing question and suggest that many individual border cells maintain ability to contribute to multiple ectodermal lineages until or beyond neural tube closure. DOI: http://dx.doi.org/10.7554/eLife.21620.001 PMID:28355135

  6. The relationship between interfragmentary movement and cell differentiation in early fracture healing under locking plate fixation.

    Science.gov (United States)

    Miramini, Saeed; Zhang, Lihai; Richardson, Martin; Mendis, Priyan; Oloyede, Adekunle; Ebeling, Peter

    2016-03-01

    Interfragmentary movement (IFM) at the fracture site plays an important role in fracture healing, particularly during its early stage, via influencing the mechanical microenvironment of mesenchymal stem cells within the fracture callus. However, the effect of changes in IFM resulting from the changes in the configuration of locking plate fixation on cell differentiation has not yet been fully understood. In this study, mechanical experiments on surrogate tibia specimens, manufactured from specially formulated polyurethane, were conducted to investigate changes in IFM of fractures under various locking plate fixation configurations and loading magnitudes. The effect of the observed IFM on callus cell differentiation was then further studied using computational simulation. We found that during the early stage, cell differentiation in the fracture callus is highly influenced by fracture gap size and IFM, which in turn, is highly sensitive to locking plate fixation configuration. The computational model predicted that a small gap size (e.g. 1 mm) under a relatively flexible configuration of locking plate fixation (larger bone-plate distances and working lengths) could experience excessive strain and fluid flow within the fracture site, resulting in excessive fibrous tissue differentiation and delayed healing. By contrast, a relatively flexible configuration of locking plate fixation was predicted to improve cartilaginous callus formation and bone healing for a relatively larger gap size (e.g. 3 mm). If further confirmed by animal and human studies, the research outcome of this paper may have implications for orthopaedic surgeons in optimising the application of locking plate fixations for fractures in clinical practice.

  7. Comparison between rough and smooth plates within the same Rayleigh-Benard cell

    Science.gov (United States)

    Rusaouen, Eleonore; Salort, Julien; Seychelles, Fanny; Tisserand, Jean-Christophe; Creyssels, Matthieu; Liot, Olivier; Castaing, Bernard; Chilla, Francesca

    2012-11-01

    A Rayleigh-Benard cell consist in a tank filled of a fluid on which a temperature difference is imposed thanks to a cold plate at top and a hot at bottom. Movement is induced by the buoyancy force. Considering most of experimental apparatus previously used all around the world, both plates are smooth. Recently, the effect of roughness on thermal transfer had become a subject of interest. The present experiment is an asymetrical rough Rayleigh-Benard cell. Indeed the hot plate is rough whereas the cold plate is still smooth. Previously, tests conducted with 2 mm high roughness showed independence of the two plates and a heat flux enhancement on the rough plate, which appeared to be greater than expected from the surface increase. This regime was caracterized by a Nu ~ Ra 1 / 2 law. New results obtained with a 4mm high roughness also show this flux enhancement and the independent behaviour of the plates. But a transition appears at high Rayleigh from the 1/2 power law regime to a 1/3 one. Former results obtained in the same symetrical smooth/smooth cell also showed a 1/3 law. But the rough 1/3 regime reveals a multiplier coefficient of 1.6 with the smooth one.

  8. Arabidopsis R-SNARE proteins VAMP721 and VAMP722 are required for cell plate formation.

    Directory of Open Access Journals (Sweden)

    Liang Zhang

    Full Text Available BACKGROUND: Cell plate formation during plant cytokinesis is facilitated by SNARE complex-mediated vesicle fusion at the cell-division plane. However, our knowledge regarding R-SNARE components of membrane fusion machinery for cell plate formation remains quite limited. METHODOLOGY/PRINCIPAL FINDINGS: We report the in vivo function of Arabidopsis VAMP721 and VAMP722, two closely sequence-related R-SNAREs, in cell plate formation. Double homozygous vamp721vamp722 mutant seedlings showed lethal dwarf phenotypes and were characterized by rudimentary roots, cotyledons and hypocotyls. Furthermore, cell wall stubs and incomplete cytokinesis were frequently observed in vamp721vamp722 seedlings. Confocal images revealed that green fluorescent protein-tagged VAMP721 and VAMP722 were preferentially localized to the expanding cell plates in dividing cells. Drug treatments and co-localization analyses demonstrated that punctuate organelles labeled with VAMP721 and VAMP722 represented early endosomes overlapped with VHA-a1-labeled TGN, which were distinct from Golgi stacks and prevacuolar compartments. In addition, protein traffic to the plasma membrane, but not to the vacuole, was severely disrupted in vamp721vamp722 seedlings by subcellular localization of marker proteins. CONCLUSION/SIGNIFICANCE: These observations suggest that VAMP721 and VAMP722 are involved in secretory trafficking to the plasma membrane via TGN/early endosomal compartment, which contributes substantially to cell plate formation during plant cytokinesis.

  9. Development of bipolar plates with different flow channel configurations for fuel cells

    Science.gov (United States)

    Boddu, Rajesh; Marupakula, Uday Kumar; Summers, Benjamin; Majumdar, Pradip

    Bipolar plates include separate gas flow channels for anode and cathode electrodes of a fuel cell. These gases flow channels supply reactant gasses as well as remove products from the cathode side of the fuel cell. Fluid flow, heat and mass transport processes in these channels have significant effect on fuel cell performance, particularly to the mass transport losses. The design of the bipolar plates should minimize plate thickness for low volume and mass. Additionally, contact faces should provide a high degree of surface uniformity for low thermal and electrical contact resistances. Finally, the flow fields should provide for efficient heat and mass transport processes with reduced pressure drops. In this study, bipolar plates with different serpentine flow channel configurations are analyzed using computational fluid dynamics modeling. Flow characteristics including variation of pressure in the flow channel across the bipolar plate are presented. Pressure drop characteristics for different flow channel designs are compared. Results show that with increased number of parallel channels and smaller sizes, a more effective contact surface area along with decreased pressured drop can be achieved. Correlations of such entrance region coefficients will be useful for the PEM fuel cell simulation model to evaluate the affects of the bipolar plate design on mass transfer loss and hence on the total current and power density of the fuel cell.

  10. Dimensional metrology of bipolar fuel cell plates using laser spot triangulation probes

    Science.gov (United States)

    Muralikrishnan, Bala; Ren, Wei; Everett, Dennis; Stanfield, Eric; Doiron, Ted

    2011-07-01

    As in any engineering component, manufacturing a bipolar fuel cell plate for a polymer electrolyte membrane (PEM) hydrogen fuel cell power stack to within its stated design tolerances is critical in achieving the intended function. In a bipolar fuel cell plate, the dimensional features of interest include channel width, channel height, channel parallelism, side wall taper, straightness of the bottom or side walls, plate parallelism, etc. Such measurements can be performed on coordinate measuring machines (CMMs) with micro-probes that can access the narrow channels. While CMM measurements provide high accuracy (less than 1 µm), they are often very slow (taking several hours to measure a single plate) and unsuitable for the manufacturing environment. In this context, we describe a system for rapid dimensional measurement of bipolar fuel cell plates using two laser spot triangulation probes that can achieve comparable accuracies to those of a touch probe CMM, while offering manufacturers the possibility for 100% part inspection. We discuss the design of the system, present our approach to calibrating system parameters, present validation data, compare bipolar fuel cell plate measurement results with those obtained using a Mitutoyo UMAP (see footnote 1) fiber probe CMM, and finally describe the uncertainty in channel height and width measurements.

  11. A Study of the use of a Crystal as a `Quarter-Wave Plate' to Produce High Energy Circularly Polarized Photons

    CERN Multimedia

    Kononets, I

    2002-01-01

    %NA59 %title\\\\ \\\\We present a proposal to study the use of a crystal as a `quarter-wave plate' to produce high energy circularly polarized photons, starting from unpolarized electrons. The intention is to generate linearly polarized photons by letting electrons pass a crystalline target, where they interact coherently with the lattice nuclei. The photon polarization is subsequently turned into circular polarization after passing another crystal, which acts as a `quarter-wave plate'.

  12. Fabrication of CNT Dispersion Fluid by Wet-Jet Milling Method for Coating on Bipolar Plate of Fuel Cell

    Directory of Open Access Journals (Sweden)

    Anas Almowarai

    2015-01-01

    Full Text Available Water based carbon nanotube (CNT dispersion was produced by wet-jet milling method. Commercial CNT was originally agglomerated at the particle size of less than 1 mm. The wet-jet milling process exfoliated CNTs from the agglomerates and dispersed them into water. Sedimentation of the CNTs in the dispersion fluid was not observed for more than a month. The produced CNT dispersion was characterized by the SEM and the viscometer. CNT/PTFE composite film was formed with the CNT dispersion in this study. The electrical conductivity of the composite film increased to 10 times when the CNT dispersion, which was produced by the wet-jet milling method, was used as a constituent of the film. Moreover, the composite film was applied to bipolar plate of fuel cell and increased the output power of the fuel cell to 1.3 times.

  13. Physical impaction injury effects on bacterial cells during spread plating influenced by cell characteristics of the organisms.

    Science.gov (United States)

    Thomas, P; Mujawar, M M; Sekhar, A C; Upreti, R

    2014-04-01

    To understand the factors that contribute to the variations in colony-forming units (CFU) in different bacteria during spread plating. Employing a mix culture of vegetative cells of ten organisms varying in cell characteristics (Gram reaction, cell shape and cell size), spread plating to the extent of just drying the agar surface (50-60 s) was tested in comparison with the alternate spotting-and-tilt-spreading (SATS) approach where 100 μl inoculum was distributed by mere tilting of plate after spotting as 20-25 microdrops. The former imparted a significant reduction in CFU by 20% over the spreader-independent SATS approach. Extending the testing to single organisms, Gram-negative proteobacteria with relatively larger cells (Escherichia, Enterobacter, Agrobacterium, Ralstonia, Pantoea, Pseudomonas and Sphingomonas spp.) showed significant CFU reduction with spread plating except for slow-growing Methylobacterium sp., while those with small rods (Xenophilus sp.) and cocci (Acinetobacter sp.) were less affected. Among Gram-positive nonspore formers, Staphylococcus epidermidis showed significant CFU reduction while Staphylococcus haemolyticus and actinobacteria (Microbacterium, Cellulosimicrobium and Brachybacterium spp.) with small rods/cocci were unaffected. Vegetative cells of Bacillus pumilus and B. subtilis were generally unaffected while others with larger rods (B. thuringiensis, Brevibacillus, Lysinibacillus and Paenibacillus spp.) were significantly affected. A simulated plating study coupled with live-dead bacterial staining endorsed the chances of cell disruption with spreader impaction in afflicted organisms. Significant reduction in CFU could occur during spread plating due to physical impaction injury to bacterial cells depending on the spreader usage and the variable effects on different organisms are determined by Gram reaction, cell size and cell shape. The inoculum spreader could impart physical disruption of vegetative cells against a hard surface

  14. Front-side metallization of silicon solar cells by nickel plating and light induced silver plating

    Energy Technology Data Exchange (ETDEWEB)

    Aleman, M.; Bay, N.; Barucha, D.; Glunz, S.W.; Preu, R. [Fraunhofer Institut fuer Solare Energiesysteme ISE, Freiburg (Germany)

    2009-07-01

    At present, screen-printing is the industrial method of choice for forming front-side contacts. Granted, the method is robust, but results in terms of contact width and contact formation, especially for high-efficiency solar cells, are not optimal. For forming these front-side contacts, a new process was developed, not requiring an etching step, but using a laser beam for direct writing of the contact pattern. By making use of the special properties of the semiconductor substrate, a metallising step can be simultaneously carried out. The basic process, involving deposition of nickel, then silver, is described. (orig.)

  15. In vitro pancreas duodenal homeobox-1 enhances the differentiation of pancreatic ductal epithelial cells into insulin-producing cells

    Science.gov (United States)

    Liu, Tao; Wang, Chun-You; Yu, Feng; Gou, Shan-Miao; Wu, He-Shui; Xiong, Jiong-Xin; Zhou, Feng

    2007-01-01

    AIM: To observe whether pancreatic and duodenal homeobox factor-1 enhances the differentiation of pancreatic ductal epithelial cells into insulin-producing cells in vitro. METHODS: Rat pancreatic tissue was submitted to digestion by collagenase, ductal epithelial cells were separated by density gradient centrifugation and then cultured in RPMI1640 medium with 10% fetal bovine serum. After 3-5 passages, the cells were incubated in a six-well plate for 24 h before transfection of recombination plasmid XlHbox8VP16. Lightcycler quantitative real-time RT-PCR was used to detect the expression of PDX-1 and insulin mRNA in pancreatic epithelial cells. The expression of PDX-1 and insulin protein was analyzed by Western blotting. Insulin secretion was detected by radioimmunoassay. Insulin-producing cells were detected by dithizone-staining. RESULTS: XlHbox8 mRNA was expressed in pancreatic ductal epithelial cells. PDX-1 and insulin mRNA as well as PDX-1 and insulin protein were significantly increased in the transfected group. The production and insulin secretion of insulin-producing cells differentiated from pancreatic ductal epithelial cells were higher than those of the untransfected cells in vitro with a significant difference (1.32 ± 0.43 vs 3.48 ± 0.81, P < 0.01 at 5.6 mmol/L; 4.86 ± 1.15 vs 10.25 ± 1.32, P < 0.01 at 16.7 mmol/L). CONCLUSION: PDX-1 can differentiate rat pancreatic ductal epithelial cells into insulin-producing cells in vitro. In vitro PDX-1 transfection is a valuable strategy for increasing the source of insulin-producing cells. PMID:17876894

  16. Computer simulation of viscous fingering in a lifting Hele-Shaw cell with grooved plates

    Indian Academy of Sciences (India)

    Sujata Tarafdar; Soma Nag; Tapati Dutta; Suparna Sinha

    2009-10-01

    We simulate viscous fingering generated by separating two plates with a constant force, in a lifting Hele-Shaw cell. Variation in the patterns for different fluid viscosity and lifting force is studied. Viscous fingering is strongly affected by anisotropy. We report a computer simulation study of fingering patterns, where circular or square grooves are etched on to the lower plate. Results are compared with experiments.

  17. IL-10-Producing Type 1 Regulatory T Cells and Allergy

    Institute of Scientific and Technical Information of China (English)

    Kui Wu; Yutian Bi; Kun Sun; Changzheng Wang

    2007-01-01

    As an important subset of regulatory T (Treg) cells, IL-10-producing type 1 regulatory T cells (Tr1), have some different features to thymic-derived naturally occurring CD4+CD25+Foxp3+ Treg cells(nTreg cells). Similar to nTreg cells, Tr1 also play important roles in the control of allergic inflammation in several ways. There is a fine balance between Tr1 and Th2 responses in healthy subjects. Skewing of allergic-specific effctor T cells to a Tr1 phenotype appears to be a critical event in successful allergen-specific immunotherapy and glucocorticoids and β2-agonists treatment. Tr1 suppress Th2 cells and effector cells of allergic inflammation, such as eosinophils, mast cells, basophils, through producing IL-10, and perhaps TGF-β. Understanding of Tr1 may be helpful in developing new strategies for treatment of allergic diseases.

  18. Constraints on plate tectonics initiation from scaling laws for single-cell convection

    Science.gov (United States)

    Wong, Teresa; Solomatov, Viatcheslav S.

    2016-08-01

    The Earth is the only planet known to have plate tectonics, while other planets are covered with a stagnant lid. On the Earth, the initiation of subduction, which is thought to be the fundamental process for plate tectonics initiation, is caused not only by the negative buoyancy of the lithosphere but also by the forces from plate motions. However, for planets which do not have plate tectonics, the very first episode of lithospheric failure has to be caused by forces other than plate motions. Sublithospheric convection has been proposed as a possible mechanism that provides lithospheric instability through inducing stresses in the lithosphere, and lithospheric failure can occur when the yield stress is below a critical value. We test the applicability of scaling laws for the critical yield stress obtained in single-cell convection simulations to strongly time-dependent multi-cell systems. We show that with an appropriate choice of characteristic aspect ratio for the convective system, the scaling laws from single-cell simulations can be used to evaluate the conditions on the terrestrial planets in the inner Solar System for plate tectonics to exist. In agreement with previous studies, the estimated values for critical yield stress and coefficient of friction are much lower than the expected values for the Earth's lithosphere.

  19. In vitro pancreas duodenal homeobox-1 enhances the differentiation of pancreatic ductal epithelial cells into insulin-producing cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To observe whether pancreatic and duodenal homeobox factor-1 enhances the differentiation of pancreatic ductal epithelial cells into insulin-producing cells in vitro.METHODS: Rat pancreatic tissue was submitted to digestion by collegenase, ductal epithelial cells were separated by density gradient centrifugation and then cultured in RPMI1640 medium with 10% fetal bovine serum. After 3-5 passages, the cells were incubated in a six-well plate for 24 h before transfection of recombination plasmid XIHbox8VP16. Lightcycler quantitative real-time RT-PCR was used to detect the expression of PDX-1 and insulin mRNA in pancreatic epithelial cells. The expression of PDX-1 and insulin protein was analyzed by Western blotting. Insulin secretion was detected by radioimmunoassay. Insulinproducing cells were detected by dithizone-staining.RESULTS: XIHbox8 mRNA was expressed in pancreatic ductal epithelial cells. PDX-1 and insulin mRNA as well as PDX-1 and insulin protein were significantly increased in the transfected group. The production and insulin secretion of insulin-producing cells differentiated from pancreatic ductal epithelial cells were higher than those of the untransfected cells in vitro with a significant difference (1.32 ± 0.43 vs 3.48 ± 0.81, P < 0.01 at 5.6 mmol/L; 4.86 ± 1.15 vs 10.25 ± 1.32, P < 0.01 at 16.7 mmol/L).CONCLUSION: PDX-1 can differentiate rat pancreatic ductal epithelial cells into insulin-producing cells in vitro.In vitro PDX-1 transfection is a valuable strategy for increasing the source of insulin-producing cells.

  20. Host cells and methods for producing isoprenyl alkanoates

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Taek Soon; Fortman, Jeffrey L.; Keasling, Jay D.

    2015-12-01

    The invention provides for a method of producing an isoprenyl alkanoate in a genetically modified host cell. In one embodiment, the method comprises culturing a genetically modified host cell which expresses an enzyme capable of catalyzing the esterification of an isoprenol and a straight-chain fatty acid, such as an alcohol acetyltransferase (AAT), wax ester synthase/diacylglycerol acyltransferase (WS/DGAT) or lipase, under a suitable condition so that the isoprenyl alkanoate is produced.

  1. A Review of Metallic Bipolar Plates for Proton Exchange Membrane Fuel Cells: Materials and Fabrication Methods

    Directory of Open Access Journals (Sweden)

    Shahram Karimi

    2012-01-01

    Full Text Available The proton exchange membrane fuel cell offers an exceptional potential for a clean, efficient, and reliable power source. The bipolar plate is a key component in this device, as it connects each cell electrically, supplies reactant gases to both anode and cathode, and removes reaction products from the cell. Bipolar plates have been fabricated primarily from high-density graphite, but in recent years, much attention has been paid to developing cost-effective and feasible alternative materials. Two different classes of materials have attracted attention: metals and composites. This paper offers a comprehensive review of the current research being carried out on metallic bipolar plates, covering materials and fabrication methods.

  2. Sphingosine-1-phosphate receptors regulate individual cell behaviours underlying the directed migration of prechordal plate progenitor cells during zebrafish gastrulation.

    Science.gov (United States)

    Kai, Masatake; Heisenberg, Carl-Philipp; Tada, Masazumi

    2008-09-01

    During vertebrate gastrulation, cells forming the prechordal plate undergo directed migration as a cohesive cluster. Recent studies revealed that E-cadherin-mediated coherence between these cells plays an important role in effective anterior migration, and that platelet-derived growth factor (Pdgf) appears to act as a guidance cue in this process. However, the mechanisms underlying this process at the individual cell level remain poorly understood. We have identified miles apart (mil) as a suppressor of defective anterior migration of the prospective prechordal plate in silberblick (slb)/wnt11 mutant embryos, in which E-cadherin-mediated coherence of cell movement is reduced. mil encodes Edg5, a sphingosine-1-phosphate (S1P) receptor belonging to a family of five G-protein-coupled receptors (S1PRs). S1P is a lipid signalling molecule that has been implicated in regulating cytoskeletal rearrangements, cell motility and cell adhesion in a variety of cell types. We examined the roles of Mil in anterior migration of prechordal plate progenitor cells and found that, in slb embryos injected with mil-MO, cells migrate with increased motility but decreased directionality, without restoring the coherence of cell migration. This indicates that prechordal plate progenitor cells can migrate effectively as individuals, as well as in a coherent cluster of cells. Moreover, we demonstrate that Mil regulates cell motility and polarisation through Pdgf and its intracellular effecter PI3K, but modulates cell coherence independently of the Pdgf/PI3K pathway, thus co-ordinating cell motility and coherence. These results suggest that the net migration of prechordal plate progenitors is determined by different parameters, including motility, persistence and coherence.

  3. High lipid order of Arabidopsis cell-plate membranes mediated by sterol and DYNAMIN-RELATED PROTEIN1A function.

    Science.gov (United States)

    Frescatada-Rosa, Márcia; Stanislas, Thomas; Backues, Steven K; Reichardt, Ilka; Men, Shuzhen; Boutté, Yohann; Jürgens, Gerd; Moritz, Thomas; Bednarek, Sebastian Y; Grebe, Markus

    2014-12-01

    Membranes of eukaryotic cells contain high lipid-order sterol-rich domains that are thought to mediate temporal and spatial organization of cellular processes. Sterols are crucial for execution of cytokinesis, the last stage of cell division, in diverse eukaryotes. The cell plate of higher-plant cells is the membrane structure that separates daughter cells during somatic cytokinesis. Cell-plate formation in Arabidopsis relies on sterol- and DYNAMIN-RELATED PROTEIN1A (DRP1A)-dependent endocytosis. However, functional relationships between lipid membrane order or lipid packing and endocytic machinery components during eukaryotic cytokinesis have not been elucidated. Using ratiometric live imaging of lipid order-sensitive fluorescent probes, we show that the cell plate of Arabidopsis thaliana represents a dynamic, high lipid-order membrane domain. The cell-plate lipid order was found to be sensitive to pharmacological and genetic alterations of sterol composition. Sterols co-localize with DRP1A at the cell plate, and DRP1A accumulates in detergent-resistant membrane fractions. Modifications of sterol concentration or composition reduce cell-plate membrane order and affect DRP1A localization. Strikingly, DRP1A function itself is essential for high lipid order at the cell plate. Our findings provide evidence that the cell plate represents a high lipid-order domain, and pave the way to explore potential feedback between lipid order and function of dynamin-related proteins during cytokinesis.

  4. Evaluation of an immunochromatographic assay for direct identification of thermostable direct hemolysin-producing Vibrio parahaemolyticus colonies on selective agar plates.

    Science.gov (United States)

    Kawatsu, Kentaro; Sakata, Junko; Yonekita, Taro; Kumeda, Yuko

    2015-12-01

    We evaluated the utility of an immunochromatographic assay (NH IC TDH) in identifying thermostable direct hemolysin (TDH)-producing Vibrio parahaemolyticus colonies on selective agar plates. The sensitivity of the NH IC TDH assay was 100% (189 samples) and its specificity was 100% (41 samples) compared with the presence of tdh.

  5. Monobactam and aminoglycoside combination therapy against metallo-beta-lactamase-producing multidrug-resistant Pseudomonas aeruginosa screened using a 'break-point checkerboard plate'.

    Science.gov (United States)

    Araoka, Hideki; Baba, Masaru; Takagi, Shinsuke; Matsuno, Naofumi; Ishiwata, Kazuya; Nakano, Nobuaki; Tsuji, Masanori; Yamamoto, Hisashi; Seo, Sachiko; Asano-Mori, Yuki; Uchida, Naoyuki; Masuoka, Kazuhiro; Wake, Atsushi; Taniguchi, Shuichi; Yoneyama, Akiko

    2010-03-01

    Metallo-beta-lactamase-producing multidrug-resistant Pseudomonas aeruginosa (MDR P. aeruginosa) is a cause of life-threatening infections. With parenteral colistin not available in Japan, we treated MDR P. aeruginosa sepsis with monobactam and aminoglycoside combination therapy, with screening using a 'break-point checkerboard plate'.

  6. Design and performance of tubular flat-plate solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, T.; Ikeda, D.; Kanagawa, H. [NTT Integrated Information & Energy Systems Labs., Tokyo (Japan)] [and others

    1996-12-31

    With the growing interest in conserving the environmental conditions, much attention is being paid to Solid Oxide Fuel Cell (SOFC), which has high energy-conversion efficiency. Many organizations have conducted studies on tubular and flat type SOFCs. Nippon Telegraph and Telephone Corporation (NTT) has studied a combined tubular flat-plate SOFC, and already presented the I-V characteristics of a single cell. Here, we report the construction of a stack of this SOFC cell and successful generation tests results.

  7. Produced Water Treatment Using Microbial Fuel Cell Technology

    Energy Technology Data Exchange (ETDEWEB)

    Borole, A. P.; Campbell, R. [Campbell Applied Physics

    2011-05-20

    ORNL has developed a treatment for produced water using a combination of microbial fuel cells and electrosorption. A collaboration between Campbell Applied Physics and ORNL was initiated to further investigate development of the technology and apply it to treatment of field produced water. The project successfully demonstrated the potential of microbial fuel cells to generate electricity from organics in produced water. A steady voltage was continuously generated for several days using the system developed in this study. In addition to the extraction of electrical energy from the organic contaminants, use of the energy at the representative voltage was demonstrated for salts removal or desalination of the produced water. Thus, the technology has potential to remove organic as well as ionic contaminants with minimal energy input using this technology. This is a novel energy-efficient method to treat produced water. Funding to test the technology at larger scale is being pursued to enable application development.

  8. High-space resolution imaging plate analysis of extreme ultraviolet (EUV) light from tin laser-produced plasmas.

    Science.gov (United States)

    Musgrave, Christopher S A; Murakami, Takehiro; Ugomori, Teruyuki; Yoshida, Kensuke; Fujioka, Shinsuke; Nishimura, Hiroaki; Atarashi, Hironori; Iyoda, Tomokazu; Nagai, Keiji

    2017-03-01

    With the advent of high volume manufacturing capabilities by extreme ultraviolet lithography, constant improvements in light source design and cost-efficiency are required. Currently, light intensity and conversion efficiency (CE) measurments are obtained by charged couple devices, faraday cups etc, but also phoshpor imaging plates (IPs) (BaFBr:Eu). IPs are sensitive to light and high-energy species, which is ideal for studying extreme ultraviolet (EUV) light from laser produced plasmas (LPPs). In this work, we used IPs to observe a large angular distribution (10°-90°). We ablated a tin target by high-energy lasers (1064 nm Nd:YAG, 10(10) and 10(11) W/cm(2)) to generate the EUV light. The europium ions in the IP were trapped in a higher energy state from exposure to EUV light and high-energy species. The light intensity was angular dependent; therefore excitation of the IP depends on the angle, and so highly informative about the LPP. We obtained high-space resolution (345 μm, 0.2°) angular distribution and grazing spectrometer (5-20 nm grate) data simultaneously at different target to IP distances (103 mm and 200 mm). Two laser systems and IP types (BAS-TR and BAS-SR) were also compared. The cosine fitting values from the IP data were used to calculate the CE to be 1.6% (SD ± 0.2) at 13.5 nm 2% bandwidth. Finally, a practical assessment of IPs and a damage issue are disclosed.

  9. High-space resolution imaging plate analysis of extreme ultraviolet (EUV) light from tin laser-produced plasmas

    Science.gov (United States)

    Musgrave, Christopher S. A.; Murakami, Takehiro; Ugomori, Teruyuki; Yoshida, Kensuke; Fujioka, Shinsuke; Nishimura, Hiroaki; Atarashi, Hironori; Iyoda, Tomokazu; Nagai, Keiji

    2017-03-01

    With the advent of high volume manufacturing capabilities by extreme ultraviolet lithography, constant improvements in light source design and cost-efficiency are required. Currently, light intensity and conversion efficiency (CE) measurments are obtained by charged couple devices, faraday cups etc, but also phoshpor imaging plates (IPs) (BaFBr:Eu). IPs are sensitive to light and high-energy species, which is ideal for studying extreme ultraviolet (EUV) light from laser produced plasmas (LPPs). In this work, we used IPs to observe a large angular distribution (10°-90°). We ablated a tin target by high-energy lasers (1064 nm Nd:YAG, 1010 and 1011 W/cm2) to generate the EUV light. The europium ions in the IP were trapped in a higher energy state from exposure to EUV light and high-energy species. The light intensity was angular dependent; therefore excitation of the IP depends on the angle, and so highly informative about the LPP. We obtained high-space resolution (345 μm, 0.2°) angular distribution and grazing spectrometer (5-20 nm grate) data simultaneously at different target to IP distances (103 mm and 200 mm). Two laser systems and IP types (BAS-TR and BAS-SR) were also compared. The cosine fitting values from the IP data were used to calculate the CE to be 1.6% (SD ± 0.2) at 13.5 nm 2% bandwidth. Finally, a practical assessment of IPs and a damage issue are disclosed.

  10. Evolution of microscopic colitis to giant cell colitis without significant intraepithelial lymphocytosis or thickened collagen plate.

    Science.gov (United States)

    De Petris, Giovanni; Chen, Longwen

    2015-05-01

    Microscopic colitis (MC) is an umbrella term that encompasses lymphocytic colitis (LC) and collagenous colitis (CC). Several histological variants of these 2 entities exist; among them is the uncommon giant cell colitis (GCC), in which histiocytic giant cells (GCs) are present in background of CC or LC. We report the case of a 71-year-old woman complaining of watery diarrhea for several years that was diagnosed with CC. At follow-up, she developed giant cell colitis (GCC). Nine years later, a colectomy revealed a form of microscopic colitis in which significant intraepithelial lymphocytosis and collagen plate thickening have disappeared while GCs persisted with diffuse mononuclear cells inflammation of the lamina propria. Thinning of the collagen plate in association with GCs has been described previously. The case contributes the possibility of further evolution of MC into a pure giant cell colitis in which the prototypical manifestations of MC have all but disappeared.

  11. Flat plate vs. concentrator solar photovoltaic cells - A manufacturing cost analysis

    Science.gov (United States)

    Granon, L. A.; Coleman, M. G.

    1980-01-01

    The choice of which photovoltaic system (flat plate or concentrator) to use for utilizing solar cells to generate electricity depends mainly on the cost. A detailed, comparative manufacturing cost analysis of the two types of systems is presented. Several common assumptions, i.e., cell thickness, interest rate, power rate, factory production life, polysilicon cost, and direct labor rate are utilized in this analysis. Process sequences, cost variables, and sensitivity analyses have been studied, and results of the latter show that the most important parameters which determine manufacturing costs are concentration ratio, manufacturing volume, and cell efficiency. The total cost per watt of the flat plate solar cell is $1.45, and that of the concentrator solar cell is $1.85, the higher cost being due to the increased process complexity and material costs.

  12. Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Atteq ur Rehman

    2014-02-01

    Full Text Available Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed.

  13. Folate receptor alpha is necessary for neural plate cell apical constriction during Xenopus neural tube formation.

    Science.gov (United States)

    Balashova, Olga A; Visina, Olesya; Borodinsky, Laura N

    2017-03-02

    Folate supplementation prevents up to 70% of neural tube defects (NTDs), which result from a failure of neural tube closure during embryogenesis. The elucidation of the mechanisms underlying folate action has been challenging. This study introduces Xenopus laevis as a model to determine the cellular and molecular mechanisms involved in folate action during neural tube formation. We show that knockdown of folate receptor-α (FRα) impairs neural tube formation and leads to NTDs. FRα knockdown in neural plate cells only is necessary and sufficient to induce NTDs. FRα-deficient neural plate cells fail to constrict, resulting in widening of the neural plate midline and defective neural tube closure. Pharmacological inhibition of folate action by methotrexate during neurulation induces NTDs by inhibiting folate interaction with its uptake systems. Our findings support a model for folate receptor interacting with cell adhesion molecules, thus regulating apical cell membrane remodeling and cytoskeletal dynamics necessary for neural plate folding. Further studies in this organism may unveil novel cellular and molecular events mediated by folate and lead to new means for preventing NTDs.

  14. Systematic analysis of in vitro cell rolling using a multi-well plate microfluidic system.

    Science.gov (United States)

    Levy, Oren; Anandakumaran, Priya; Ngai, Jessica; Karnik, Rohit; Karp, Jeffrey M

    2013-10-16

    A major challenge for cell-based therapy is the inability to systemically target a large quantity of viable cells with high efficiency to tissues of interest following intravenous or intraarterial infusion. Consequently, increasing cell homing is currently studied as a strategy to improve cell therapy. Cell rolling on the vascular endothelium is an important step in the process of cell homing and can be probed in-vitro using a parallel plate flow chamber (PPFC). However, this is an extremely tedious, low throughput assay, with poorly controlled flow conditions. Instead, we used a multi-well plate microfluidic system that enables study of cellular rolling properties in a higher throughput under precisely controlled, physiologically relevant shear flow. In this paper, we show how the rolling properties of HL-60 (human promyelocytic leukemia) cells on P- and E-selectin-coated surfaces as well as on cell monolayer-coated surfaces can be readily examined. To better simulate inflammatory conditions, the microfluidic channel surface was coated with endothelial cells (ECs), which were then activated with tumor necrosis factor-α (TNF-α), significantly increasing interactions with HL-60 cells under dynamic conditions. The enhanced throughput and integrated multi-parameter software analysis platform, that permits rapid analysis of parameters such as rolling velocities and rolling path, are important advantages for assessing cell rolling properties in-vitro. Allowing rapid and accurate analysis of engineering approaches designed to impact cell rolling and homing, this platform may help advance exogenous cell-based therapy.

  15. Quantitative comparison between microfluidic and microtiter plate formats for cell-based assays.

    Science.gov (United States)

    Yin, Huabing; Pattrick, Nicola; Zhang, Xunli; Klauke, Norbert; Cordingley, Hayley C; Haswell, Steven J; Cooper, Jonathan M

    2008-01-01

    In this paper, we compare a quantitative cell-based assay measuring the intracellular Ca2+ response to the agonist uridine 5'-triphosphate in Chinese hamster ovary cells, in both microfluidic and microtiter formats. The study demonstrates that, under appropriate hydrodynamic conditions, there is an excellent agreement between traditional well-plate assays and those obtained on-chip for both suspended immobilized cells and cultured adherent cells. We also demonstrate that the on-chip assay, using adherent cells, provides the possibility of faster screening protocols with the potential for resolving subcellular information about local Ca2+ flux.

  16. Renal erythropoietin-producing cells in health and disease

    Directory of Open Access Journals (Sweden)

    Tomokazu eSouma

    2015-06-01

    Full Text Available Erythropoietin (Epo is an indispensable erythropoietic hormone primarily produced from renal Epo-producing cells (REPs. Epo production in REPs is tightly regulated in a hypoxia-inducible manner to maintain tissue oxygen homeostasis. Insufficient Epo production by REPs causes renal anemia and anemia associated with chronic disorders. Recent studies have broadened our understanding of REPs from prototypic hypoxia-responsive cells to dynamic fibrogenic cells. In chronic kidney disease, REPs are the major source of scar-forming myofibroblasts and actively produce fibrogenic molecules, including inflammatory cytokines. Notably, myofibroblast-transformed REPs recover their original physiological properties after resolution of the disease insults, suggesting that renal anemia and fibrosis could be reversible to some extent. Therefore, understanding the plasticity of REPs will lead to the development of novel targeted therapeutics for both renal fibrosis and anemia. This review summarizes the regulatory mechanisms how hypoxia-inducible Epo gene expression is attained in health and disease conditions.

  17. Mast Cells Produce a Unique Chondroitin Sulfate Epitope.

    Science.gov (United States)

    Farrugia, Brooke L; Whitelock, John M; O'Grady, Robert; Caterson, Bruce; Lord, Megan S

    2016-02-01

    The granules of mast cells contain a myriad of mediators that are stored and protected by the sulfated glycosaminoglycan (GAG) chains that decorate proteoglycans. Whereas heparin is the GAG predominantly associated with mast cells, mast cell proteoglycans are also decorated with heparan sulfate and chondroitin sulfate (CS). This study investigated a unique CS structure produced by mast cells that was detected with the antibody clone 2B6 in the absence of chondroitinase ABC digestion. Mast cells in rodent tissue sections were characterized using toluidine blue, Leder stain and the presence of mast cell tryptase. The novel CS epitope was identified in rodent tissue sections and localized to cells that were morphologically similar to cells chemically identified as mast cells. The rodent mast cell-like line RBL-2H3 was also shown to express the novel CS epitope. This epitope co-localized with multiple CS proteoglycans in both rodent tissue and RBL-2H3 cultured cells. These findings suggest that the novel CS epitope that decorates mast cell proteoglycans may play a role in the way these chains are structured in mast cells.

  18. Growth hormone induces multiplication of the slowly cycling germinal cells of the rat tibial growth plate.

    Science.gov (United States)

    Ohlsson, C; Nilsson, A; Isaksson, O; Lindahl, A

    1992-10-15

    To study the effect of locally infused growth hormone (GH) or insulin-like growth factor I(IGF-I) on slowly cycling cells in the germinal cell layer of the tibial growth plate, osmotic minipumps delivering 14.3 microCi of [3H]thymidine per day were implanted s.c. into hypophysectomized rats, and GH (1 microgram) or IGF-I (10 micrograms) was injected daily through a cannula implanted in the proximal tibia. The opposite leg served as a control. After 12 days of treatment, the osmotic minipumps were removed, and three rats in each group were given GH (20 micrograms/day, s.c.) for an additional 14 days to chase the labeled cells out of the proliferative layers. Labeled cells remained in the germinal layer, in the perichondrial ring, and on the surface of the articular cartilage close to the epiphyseal plate. GH administered together with labeled thymidine significantly increased the number of labeled cells in the germinal cell layer compared to that in the control leg (ratio = 1.95 +/- 0.13), whereas IGF-I showed no stimulatory effect (ratio = 0.96 +/- 0.04). Therefore GH but not IGF-I stimulates the multiplication of the slowly cycling (label-retaining) cells in the germinal layer of the epiphyseal plate. IGF-I acts only on the proliferation of the resulting chondrocytes.

  19. Gleevec, an Abl family inhibitor, produces a profound change in cell shape and migration.

    Directory of Open Access Journals (Sweden)

    Zaozao Chen

    Full Text Available The issue of how contractility and adhesion are related to cell shape and migration pattern remains largely unresolved. In this paper we report that Gleevec (Imatinib, an Abl family kinase inhibitor, produces a profound change in the shape and migration of rat bladder tumor cells (NBTII plated on collagen-coated substrates. Cells treated with Gleevec adopt a highly spread D-shape and migrate more rapidly with greater persistence. Accompanying this more spread state is an increase in integrin-mediated adhesion coupled with increases in the size and number of discrete adhesions. In addition, both total internal reflection fluorescence microscopy (TIRFM and interference reflection microscopy (IRM revealed a band of small punctate adhesions with rapid turnover near the cell leading margin. These changes led to an increase in global cell-substrate adhesion strength, as assessed by laminar flow experiments. Gleevec-treated cells have greater RhoA activity which, via myosin activation, led to an increase in the magnitude of total traction force applied to the substrate. These chemical and physical alterations upon Gleevec treatment produce the dramatic change in morphology and migration that is observed.

  20. Quantitative analysis of textures produced in a hot-extruded zirconium plate; Analyse quantitative des textures developpees dans une plaque de zirconium filee a chaud

    Energy Technology Data Exchange (ETDEWEB)

    Couterne, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Institut national des sciences et techniques nucleaires, laboratoire de metallurgie

    1967-01-01

    The textures produced in zirconium by the extrusion at 730 deg C of a cylindrical billet in the form of a plate having a rectangular cross-section, have been studied by the Schulz method using an isotropic standard. These textures have been determined both parallel to the plane of the plate and parallel to the plane of the sides, All the results are analyzed in a final discussion which makes it possible to show, in particular near the edges of the plate, that certain components of the textures observed in the two series of recordings are in fact aspects of the same texture seen from two different angles, It is shown furthermore that the zirconium thus shaped has cold-work textures and als recrystallisation textures formed after the preceding cold-working, If the observed textures are considered schematically, it can be see that two of these have already been described in the literature and are similar to those found in rolled products: these textures are such that the (0001) planes are inclined at 36 deg C and 60 deg C respectively with respect to a plan tangential to the curve (envelope of transverse flow rates) resulting from the extrusion geometry under consideration; the third texture is defined. by the fact that the (0001) plane is orthogonal to the exterior surfaces of the plate. The direction of extrusion associated with these planes and common to the three textures is of the type <1010>, Dilatometric tests have been carried out on samples taken both parallel and perpendicular to the extrusion direction, These tests show that the zirconium is dilatometrically anisotropic and that a plot of ({alpha}{sub v})-a against temperature shows a change of gradient at 400 deg C, this latter effect may be due to the change in the electronic configuration of the metal occurring at this temperature. (author) [French] Les textures conferees au zirconium par filage a chaud a 730 deg C d'une billette cylindrique sous forme d'une plaque de section rectangulaire, ont

  1. Al slurry coatings for molten carbonate fuel cells separator plates

    Energy Technology Data Exchange (ETDEWEB)

    Agueero, A.; Garcia, M.C.; Muelas, R.; Sanchez, A. [Instituto Nacional de Tecnica Aerospacial, Madrid (Spain); Perez, F.J.; Duday, D.; Hierro, M.P.; Gomez, C. [Universidad Complutense de Madrid (Spain). Dept. de Ciencia de los Materiales

    2001-07-01

    The corrosion behaviour of Al slurry coated AISI 310 stainless steel, with and without diffusion heat treatment, was investigated as a wet seal material for molten carbonate fuel cell (MCFC) at 650 C. The results were compared with IVD Al coated AISI 310. Characterization of the samples before and after exposure to the eutectic 62 mol% Li{sub 2}CO{sub 3}-38 mol% K{sub 2}CO{sub 3} mixture at 650 C for 1000 h by SEM-EDS and XRD was carried out. The presence of LiAlO{sub 2} on the coated samples was confirmed by XRD. The slurry Al-coated stainless steels performed at least as well as the IVD Al coating. (orig.)

  2. The Fabrication of Flow Field Plates for Direct Methanol Fuel Cell Using Lithography and Radio Frequency Sputtering.

    Science.gov (United States)

    Chang, Ho; Kao, Mu-Jung; Chen, Chih-Hao; Cho, Kun-Ching; Hsu, Chun-Yao; Chen, Zhi-Lun

    2015-08-01

    This study uses lithography to etch flow fields on a single side of a printed circuit board (PCB) and combines a flow field plate with a collector plate to make innovative anode flow field plates and cathode flow field plates for a direct methanol fuel cell (DMFC). TiO2 thin film is also sputtered on the anode flow field plate using radio frequency (RF) sputtering. The experimental results show that the prepared DMFC has a better maximum power density of 11.928 mW/cm2. Furthermore, when a TiO2 thin film is sputtered on the flow field plate of the assembled DMFC, the maximum power density is 14.426 mW/cm2, which is actually 21% more than that for a DMFC with no TiO2 thin film coated on the flow field plate.

  3. Localization and biosynthesis of polyamines in insulin-producing cells

    DEFF Research Database (Denmark)

    Hougaard, D M; Larsson, L I; Nielsen, Jens Høiriis

    1986-01-01

    Two recently developed fluorescence cytochemical methods, specific for spermidine and spermine, were used to localize polyamines in the endocrine pancreas. The polyamines were restricted to the insulin-producing beta-cells and were mainly associated with the secretory granules. Chemical polyamine...

  4. Enhancement of insulin-producing cell differentiation from embryonic stem cells using pax4-nucleofection method

    Institute of Scientific and Technical Information of China (English)

    Han-Tso Lin; Hung-Hai Ku; Chung-Lan Kao; Kun-Hsiung Lee; Yuh-Lih Chang; Shih-Hwa Chiou; Fu-Ting Tsai; Tung-Hu Tsai; Dey-Chyi Sheu; Larry LT Ho

    2007-01-01

    AIM: To enhance the differentiation of insulin producing cell (IPC) ability from embryonic stem (ES) cells in vitro.METHODS: Four-day embryoid body (EB)-formatted ES cells were dissociated as single cells for the followed plasmid DNA delivery. The use of Nucleofector- Electroporator (Amaxa biosystems, Germany) in combination with medium-contained G418 provided a high efficiency of gene delivery for advanced selection. Neucleofected cells were plated on the top of fibronectin coated Petri dishes. Addition of Ly294002 and raised the glucose in medium at 24 h before examination.The differentiation status of these cells was monitored by semi-quantitative PCR (SQ-PCR) detection of the expression of relative genes, such as oct-4, sox-17, foxa2, mixl1, pdx-1, insulin 1, glucagons and somatostatin. The percentage of IPC population on d 18 of the experiment was investigated by immunohistochemistry (IHC), and the content/secretion of insulin was estimated by ELISA assay. The mice with severe combined immunodeficiency disease (SCID) pretreated with streptozotocin (STZ) were used to eliminate plasma glucose restoration after pax4+ ES implantation.RESULTS: A high efficiency of gene delivery was demonstrated when neucleofection was used in the present study; approximately 70% cells showed DsRed expression 2 d after neucleofection. By selection of medium-contained G418, the percentage of DsRed expressing cells kept high till the end of study. The pancreatic differentiation seemed to be accelerated by pax4 nucleofection. When compared to the group of cells with mock control, foxa2, mixl1, pdx1, higher insulin and somatostatin levels were detected by SQ-PCR 4 d after nucleofection in the group of pax4 expressing plasmid delivery. Approximately 55% of neucleofected cells showed insulin expression 18 d after neucleofection, and only 18% of cells showed insulin expression in mock control. The disturbance was shown by nucleofected pax4 RNAi vector; only 8% of cells expressed insulin 18

  5. Characterization of laser doped silicon and overcoming adhesion challenges of solar cells with nickel-copper plated contacts

    Energy Technology Data Exchange (ETDEWEB)

    Geisler, Christian

    2015-07-01

    The combination of localized laser patterning and metal plating allows to replace conventional silver screen printing with nickel-copper plating to form inexpensive front contacts for crystalline silicon solar cells. In this work, a focus is put on effects that could cause inhomogeneous metal deposition and low metal contact adhesion. A descriptive model of the silicon nitride ablation mechanism is derived from SEM imaging and a precise recombination analysis using QSSPC measurements. Surface sensitive XPS measurements are conducted to prove the existence of a parasitic surface layer, identified as SiO{sub x}N{sub y}. The dense SiO{sub x}N{sub y} layer is an effective diffusion barrier, hindering the formation of a nickel silicide interlayer. After removal of the SiO{sub x}N{sub y} layer, cells show severe degradation caused by metal-induced shunting. These shunts are imaged using reverse biased electroluminescence imaging. A shunting mechanism is proposed and experimentally verified. New laser process sequences are devised and proven to produce cells with adhering Ni-Cu contacts. Conclusively the developed processes are assessed based on their industrial feasibility as well as on their efficiency potential.

  6. Highly conductive, multi-layer composite precursor composition to fuel cell flow field plate or bipolar plate

    Science.gov (United States)

    Jang, Bor Z.; Zhamu, Aruna; Guo, Jiusheng

    2011-02-15

    This invention provides a moldable, multiple-layer composite composition, which is a precursor to an electrically conductive composite flow field plate or bipolar plate. In one preferred embodiment, the composition comprises a plurality of conductive sheets and a plurality of mixture layers of a curable resin and conductive fillers, wherein (A) each conductive sheet is attached to at least one resin-filler mixture layer; (B) at least one of the conductive sheets comprises flexible graphite; and (C) at least one resin-filler mixture layer comprises a thermosetting resin and conductive fillers with the fillers being present in a sufficient quantity to render the resulting flow field plate or bipolar plate electrically conductive with a conductivity no less than 100 S/cm and thickness-direction areal conductivity no less than 200 S/cm.sup.2.

  7. Micro direct methanol fuel cell with perforated silicon-plate integrated ionomer membrane

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent; Dalslet, Bjarke Thomas; Johansson, Anne-Charlotte Elisabeth Birgitta

    2014-01-01

    This article describes the fabrication and characterization of a silicon based micro direct methanol fuel cell using a Nafion ionomer membrane integrated into a perforated silicon plate. The focus of this work is to provide a platform for micro- and nanostructuring of a combined current collector...... at a perforation ratio of 40.3%. The presented fuel cells also show a high volumetric peak power density of 2 mW cm−3 in light of the small system volume of 480 μL, while being fully self contained and passively feed....... and catalytic electrode. AC impedance spectroscopy is utilized alongside IV characterization to determine the influence of the plate perforation geometries on the cell performance. It is found that higher ratios of perforation increases peak power density, with the highest achieved being 2.5 mW cm−2...

  8. Sonocatalytic injury of cancer cells attached on the surface of a nickel-titanium dioxide alloy plate.

    Science.gov (United States)

    Ninomiya, Kazuaki; Maruyama, Hirotaka; Ogino, Chiaki; Takahashi, Kenji; Shimizu, Nobuaki

    2016-01-01

    The present study demonstrates ultrasound-induced cell injury using a nickel-titanium dioxide (Ni-TiO2) alloy plate as a sonocatalyst and a cell culture surface. Ultrasound irradiation of cell-free Ni-TiO2 alloy plates with 1 MHz ultrasound at 0.5 W/cm(2) for 30s led to an increased generation of hydroxyl (OH) radicals compared to nickel-titanium (Ni-Ti) control alloy plates with and without ultrasound irradiation. When human breast cancer cells (MCF-7 cells) cultured on the Ni-TiO2 alloy plates were irradiated with 1 MHz ultrasound at 0.5 W/cm(2) for 30s and then incubated for 48 h, cell density on the alloy plate was reduced to approximately 50% of the controls on the Ni-Ti alloy plates with and without ultrasound irradiation. These results indicate the injury of MCF-7 cells following sonocatalytic OH radical generation by Ni-TiO2. Further experiments demonstrated cell shrinkage and chromatin condensation after ultrasound irradiation of MCF-7 cells attached on the Ni-TiO2 alloy plates, indicating induction of apoptosis.

  9. Experimental fuel cell performance analysis under different operating conditions and bipolar plate designs

    Energy Technology Data Exchange (ETDEWEB)

    Iranzo, Alfredo; Pino, Javier; Rosa, Felipe [Energy Engineering Department, School of Engineering, University of Seville, Camino de los Descubrimientos s/n, 41092 Seville (Spain); Munoz, Miguel; Lopez, Eduardo [INTA - National Institute for Aerospace Technology, Ctra. San Juan del Puerto-Matalascanas km 33, 21130 Mazagon (Huelva) (Spain)

    2010-10-15

    This work presents experimental performance results for a 50 cm{sup 2} Polymer Electrolyte Membrane (PEM) Fuel Cell, including polarization curves and Electrochemical Impedance Spectroscopy (EIS) analysis of the Fuel Cell. EIS results were used for the determination of the cell ohmic resistance as well as charge transfer resistances under different operating conditions. Different combinations of operating conditions and bipolar plate designs were analysed. In particular, the effect of the cathode oxygen concentration, reactant gases humidification, and bipolar plate (BP) design were assessed. Butler-Volmer (BV) kinetic parameters such as the charge transfer coefficient were also determined from Tafel plots. The electronic contact resistances were measured for both Bipolar Plate designs, and the membrane protonic resistances were calculated. Its dependence on the BP flow field design and operating conditions is addressed. The results obtained in this work are aimed both at gaining insight into the fundamental processes determining the fuel cell performance, and at determining parameters needed for Computational Fuel Cell Dynamics (CFCD) numerical simulations. (author)

  10. Heating produced by therapeutic ultrasound in the presence of a metal plate in the femur of canine cadavers

    Directory of Open Access Journals (Sweden)

    A.O. Andrades

    2014-10-01

    Full Text Available The present study aimed to assess the heat generated by a therapeutic ultrasound (TUS in a metal bone plate and adjacent structures after fixation to the femur of canine cadavers. Ten pairs of hind limbs were used, and they were equally distributed between groups that were subjected to 1- and 3-MHz frequencies, with each frequency testing 1- and 2-W/cm² intensities. The right hind limb was defined as the control group (absence of the metal plate, and the left hind limb was the test group (presence of the metal plate. Therefore, the control groups (CG were denominated CGI, using TUS with 1-MHz frequency and 1-W/cm² intensity; CGII, using 1-MHz frequency and 2-W/cm² intensity; CGIII, using 3-MHz frequency and 1-W/cm² intensity; and CGIV, using 3-MHz frequency and 2-W/cm² intensity. For each control group, its respective test group (TG was denominated TGI, TGII, TGIII and TGIV. The TUS was applied to the lateral aspect of the thigh using the continuous mode and a 3.5-cm² transducer in a 6.25-cm² area for 2 minutes. Sensors were coupled to digital thermometers that measured the temperature in different sites before (t0 and after (t1 of the TUS application. The temperatures in t1 were higher in all tested groups. The intramuscular temperature was significantly higher (P<0.05 in the groups used to test the 3-MHz frequency in the presence of the metal plate. The therapeutic ultrasound in the continuous mode using frequencies of 1 and 3 MHz and intensities of 1 and 2 W/cm2 for 2 minutes caused heating of the metal plate and adjacent structures after fixation to the femur of canine cadavers.

  11. Isolation and characterization of renal erythropoietin-producing cells from genetically produced anemia mice.

    Directory of Open Access Journals (Sweden)

    Xiaoqing Pan

    Full Text Available Understanding the nature of renal erythropoietin-producing cells (REPs remains a central challenge for elucidating the mechanisms involved in hypoxia and/or anemia-induced erythropoietin (Epo production in adult mammals. Previous studies have shown that REPs are renal peritubular cells, but further details are lacking. Here, we describe an approach to isolate and characterize REPs. We bred mice bearing an Epo gene allele to which green fluorescent protein (GFP reporter cDNA was knocked-in (Epo(GFP with mice bearing an Epo gene allele lacking the 3' enhancer (Epo(Δ3'E. Mice harboring the mutant Epo(GFP/Δ3'E gene exhibited anemia (average Hematocrit 18% at 4 to 6 days after birth, and this perinatal anemia enabled us to identify and purify REPs based on GFP expression from the kidney. Light and confocal microscopy revealed that GFP immunostaining was confined to fibroblastic cells that reside in the peritubular interstitial space, confirming our previous observation in Epo-GFP transgenic reporter assays. Flow cytometry analyses revealed that the GFP fraction constitutes approximately 0.2% of the whole kidney cells and 63% of GFP-positive cells co-express CD73 (a marker for cortical fibroblasts and Epo-expressing cells in the kidney. Quantitative RT-PCR analyses confirmed that Epo expression was increased by approximately 100-fold in the purified population of REPs compared with that of the unsorted cells or CD73-positive fraction. Gene expression analyses showed enrichment of Hif2α and Hif3α mRNA in the purified population of REPs. The genetic approach described here provides a means to isolate a pure population of REPs, allowing the analysis of gene expression of a defined population of cells essential for Epo production in the kidney. This has provided evidence that positive regulation by HIF2α and negative regulation by HIF3α might be necessary for correct renal Epo induction.

  12. Development of alternative low-cost and durable metallic bipolar plates for polymer electrolyte membrane (PEM) fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Okafor, A.C.; Kilicay, O. [Missouri Univ. of Science and Technology, Rolla (United States). Dept. of Mechanical and Aerospace Engineering

    2009-07-01

    Bipolar plates account for significant portion of the cost of proton exchange membrane fuel cells (PEMFCs). This study discussed the design of a high corrosion-resistance metallic bipolar plate as an alternative to the porous graphite bipolar plates currently used in PEMFCs. A literature review of bipolar plate materials and flow field design configurations was conducted. Metallic candidate materials and flow field configurations were identified. Computer-aided design (CAD) models were then development in order to design the software programs used to machine the bipolar plates in 3 different materials. The machined bipolar plates are now being integrated with state-of-the-art membrane electrode assemblies (MEAs) and sealants into single- and 3-cell stacks. The results of some performance, durability, and degradation mechanism analyses were presented.

  13. End plate for e.g. solid oxide fuel cell stack, sets thermal expansion coefficient of material to predetermined value

    DEFF Research Database (Denmark)

    2011-01-01

    .05-0.3 mm. USE - End plate for solid oxide fuel cell stack (claimed). Can also be used in polymer electrolyte fuel cell stack and direct methanol fuel cell stack. ADVANTAGE - The robustness of the end plate is improved. The structure of the end plate is simplified. The risk of delamination of the stack......NOVELTY - The end plate is made of material whose thermal expansion coefficient is corresponding to that of material of a cell (103). The thermal expansion coefficient of material is 9asterisk10-6 K-1 to 14asterisk10-6 K11. The thickness of the end plate is within the range of 0.001-1 mm and 0...

  14. A dynamic cell adhesion surface regulates tissue architecture in growth plate cartilage.

    Science.gov (United States)

    Romereim, Sarah M; Conoan, Nicholas H; Chen, Baojiang; Dudley, Andrew T

    2014-05-01

    The architecture and morphogenetic properties of tissues are founded in the tissue-specific regulation of cell behaviors. In endochondral bones, the growth plate cartilage promotes bone elongation via regulated chondrocyte maturation within an ordered, three-dimensional cell array. A key event in the process that generates this cell array is the transformation of disordered resting chondrocytes into clonal columns of discoid proliferative cells aligned with the primary growth vector. Previous analysis showed that column-forming chondrocytes display planar cell divisions, and the resulting daughter cells rearrange by ∼90° to align with the lengthening column. However, these previous studies provided limited information about the mechanisms underlying this dynamic process. Here we present new mechanistic insights generated by application of a novel time-lapse confocal microscopy method along with immunofluorescence and electron microscopy. We show that, during cell division, daughter chondrocytes establish a cell-cell adhesion surface enriched in cadherins and β-catenin. Rearrangement into columns occurs concomitant with expansion of this adhesion surface in a process more similar to cell spreading than to migration. Column formation requires cell-cell adhesion, as reducing cadherin binding via chelation of extracellular calcium inhibits chondrocyte rearrangement. Importantly, physical indicators of cell polarity, such as cell body alignment, are not prerequisites for oriented cell behavior. Our results support a model in which regulation of adhesive surface dynamics and cortical tension by extrinsic signaling modifies the thermodynamic landscape to promote organization of daughter cells in the context of the three-dimensional growth plate tissue.

  15. Comprehensive Profiling of GPCR Expression in Ghrelin-Producing Cells.

    Science.gov (United States)

    Koyama, Hiroyuki; Iwakura, Hiroshi; Dote, Katsuko; Bando, Mika; Hosoda, Hiroshi; Ariyasu, Hiroyuki; Kusakabe, Toru; Son, Choel; Hosoda, Kiminori; Akamizu, Takashi; Kangawa, Kenji; Nakao, Kazuwa

    2016-02-01

    To determine the comprehensive G protein-coupled receptor (GPCR) expression profile in ghrelin-producing cells and to elucidate the role of GPCR-mediated signaling in the regulation of ghrelin secretion, we determined GPCR expression profiles by RNA sequencing in the ghrelin-producing cell line MGN3-1 and analyzed the effects of ligands for highly expressed receptors on intracellular signaling and ghrelin secretion. Expression of selected GPCRs was confirmed in fluorescence-activated cell-sorted fluorescently tagged ghrelin-producing cells from ghrelin-promoter CreERT2/Rosa-CAG-LSL-ZsGreen1 mice. Expression levels of GPCRs previously suggested to regulate ghrelin secretion including adrenergic-β1 receptor, GPR81, oxytocin receptor, GPR120, and somatostatin receptor 2 were high in MGN3-1 cells. Consistent with previous reports, isoproterenol and oxytocin stimulated the Gs and Gq pathways, respectively, whereas lactate, palmitate, and somatostatin stimulated the Gi pathway, confirming the reliability of current assays. Among other highly expressed GPCRs, prostaglandin E receptor 4 agonist prostaglandin E2 significantly stimulated the Gs pathway and ghrelin secretion. Muscarine, the canonical agonist of cholinergic receptor muscarinic 4, stimulated both the Gq and Gi pathways. Although muscarine treatment alone did not affect ghrelin secretion, it did suppress forskolin-induced ghrelin secretion, suggesting that the cholinergic pathway may play a role in counterbalancing the stimulation of ghrelin by Gs (eg, by adrenaline). In addition, GPR142 ligand tryptophan stimulated ghrelin secretion. In conclusion, we determined the comprehensive expression profile of GPCRs in ghrelin-producing cells and identified two novel ghrelin regulators, prostaglandin E2 and tryptophan. These results will lead to a greater understanding of the physiology of ghrelin and facilitate the development of ghrelin-modulating drugs.

  16. Establishment of a new bovine leukosis virus producing cell line.

    Science.gov (United States)

    Beier, D; Riebe, R; Blankenstein, P; Starick, E; Bondzio, A; Marquardt, O

    2004-11-01

    Due to the prevalence of different bovine leukosis virus (BLV) species in the cattle population in Europe, problems may arise in the serological diagnosis of BLV infections. In addition, earlier investigations demonstrated that contamination of the BLV antigen-producing cell culture systems by bovine viral diarrhea virus (BVDV) may give rise to misinterpretation of serological test results after BVDV vaccination of cattle. By co-cultivation of peripheral leukocytes of a BLV-infected cow with a permanent sheep kidney cell line, a new BLV-producing cell line named PO714 was established. This line carries a BLV provirus of the Belgian species and has been tested to be free of a variety of possibly contaminating viruses and mycoplasms. Investigations of a panel of well-characterised sera by agar gel immunodiffusion (AGID) and capture ELISA (cELISA) tests using antigen prepared from this new cell line in comparison with antigen of the well-known cell line FLK/BLV yielded comparable results. False positive results caused by BVDV cross-reactions could be eliminated when tests were carried out with antigen derived from the new cell line.

  17. Improving poor fill factors for solar cells via light-induced plating

    Institute of Scientific and Technical Information of China (English)

    Xing Zhao; Jia Rui; Ding Wuchang; Meng Yanlong; Jin Zhi; Liu Xinyu

    2012-01-01

    Silicon solar cells are prepared following the conventional fabrication processes,except for the metallization firing process.The cells are divided into two groups with higher and lower fill factors,respectively.After light-induced plating (LIP),the fill factors of the solar cells in both groups with different initial values reach the same level.Scanning electron microscope (SEM) images are taken under the bulk silver electrodes,which prove that the improvement for cells with a poor factor after LIP should benefit from sufficient exploitation of the high density silver crystals formed during the firing process.Moreover,the application of LIP to cells with poor electrode contact performance,such as nanowire cells and radial junction solar cells,is proposed.

  18. Silver and tin plating as medieval techniques of producing counterfeit coins and their identification by means of micro-XRF

    Science.gov (United States)

    Hložek, M.; Trojek, T.

    2017-08-01

    Archaeological surveys and metal detector prospecting yield a great amount of coins from the medieval period. Naturally, some of these are counterfeit which an experienced numismatist can determine without using chemical methods. The production of counterfeit coins in the middle ages took place in castles, caves or other remote areas where waste from this activity can still be found today - copper sheets, technical ceramics and counterfeit coins. Until recently, it has been assumed that medieval counterfeit coins are made by silver-plating copper blanks using an amalgam. However, the performed analyses reveal that there are many more techniques of counterfeiting of coins. Other techniques were based on e.g. tin amalgam plating of the blanks or alloying so-called white metal with silver-like appearance from which the coins were minted. Current chemical analyses indicate that the coins were often tinned by hot dipping with no amalgamation. Micro-X-ray fluorescence analysis has been chosen as a suitable non-destructive method to identify present chemical elements in investigated artifacts and to quantify their concentrations. In addition, a quick technique telltale the plating was applied. This technique utilizes the detected fluorescence ratio Kα/Kβ of copper, which is the main ingredient of a lot of historical metallic materials.

  19. Cell agglomeration in the wells of a 24-well plate using acoustic streaming.

    Science.gov (United States)

    Kurashina, Yuta; Takemura, Kenjiro; Friend, James

    2017-02-28

    Cell agglomeration is essential both to the success of drug testing and to the development of tissue engineering. Here, a MHz-order acoustic wave is used to generate acoustic streaming in the wells of a 24-well plate to drive particle and cell agglomeration. Acoustic streaming is known to manipulate particles in microfluidic devices, and even provide concentration in sessile droplets, but concentration of particles or cells in individual wells has never been shown, principally due to the drag present along the periphery of the fluid in such a well. The agglomeration time for a range of particle sizes suggests that shear-induced migration plays an important role in the agglomeration process. Particles with a diameter of 45 μm agglomerated into a suspended pellet under exposure to 2.134 MHz acoustic waves at 1.5 W in 30 s. Additionally, BT-474 cells also agglomerated as adherent masses at the center bottom of the wells of tissue-culture treated 24-well plates. By switching to low cell binding 24-well plates, the BT-474 cells formed suspended agglomerations that appeared to be spheroids, fully fifteen times larger than any cell agglomerates without the acoustic streaming. In either case, the viability and proliferation of the cells were maintained despite acoustic irradiation and streaming. Intermittent excitation was effective in avoiding temperature excursions, consuming only 75 mW per well on average, presenting a convenient means to form fully three-dimensional cellular masses potentially useful for tissue, cancer, and drug research.

  20. Cost and performance prospects for composite bipolar plates in fuel cells and redox flow batteries

    Science.gov (United States)

    Minke, Christine; Hickmann, Thorsten; dos Santos, Antonio R.; Kunz, Ulrich; Turek, Thomas

    2016-02-01

    Carbon-polymer-composite bipolar plates (BPP) are suitable for fuel cell and flow battery applications. The advantages of both components are combined in a product with high electrical conductivity and good processability in convenient polymer forming processes. In a comprehensive techno-economic analysis of materials and production processes cost factors are quantified. For the first time a technical cost model for BPP is set up with tight integration of material characterization measurements.

  1. Putative Porcine Embryonic Stem Cell Lines Derived from Aggregated Four-Celled Cloned Embryos Produced by Oocyte Bisection Cloning

    Science.gov (United States)

    Siriboon, Chawalit; Lin, Yu-Hsuan; Kere, Michel; Chen, Chun-Da; Chen, Lih-Ren; Chen, Chien-Hong; Tu, Ching-Fu; Lo, Neng-Wen; Ju, Jyh-Cherng

    2015-01-01

    We attempted to isolate ES cell lines using inner cell masses from high-quality cloned porcine blastocysts. After being seeded onto feeders, embryos had better (P cells were examined. More (17.1%) ntES cell lines over Passage 3 were generated in the MEF/KSR group. However, ntES cells cultured in KSR-supplemented medium had a low proliferation rate with defective morphology, and eventually underwent differentiation or apoptosis subsequently. Approximately 26.1, 22.7 and 35.7% of primary colonies were formed after plating embryos in DMEM, DMEM/F12 and α-MEM media, respectively. Survival rates of ntES cells cultured in α-MEM, DMEM and DMEM/F12 were 16.7, 4.3 and 6.8%, respectively (P > 0.05). We further examined the beneficial effect of TSA treatment of 3× aggregated cloned embryos on establishment of ntES cell lines. Primary colony numbers and survival rates of ntES cells beyond passage 3 were higher (P cells, remaining undifferentiated over 25 passages, had alkaline phosphatase activity and expressed ES specific markers Oct4, Nanog, Sox2, and Rex01. Moreover, these ntES cells successfully differentiated into embryoid bodies (EBs) that expressed specific genes of all three germ layers after being cultured in LIF-free medium. In conclusion, we have successfully derived putative porcine ntES cells with high efficiency from quality cloned embryos produced by embryo aggregation, and optimized the ES cell culture system suitable for establishing and maintaining ntES cell lines in undifferentiated state. PMID:25680105

  2. Orientation of Cells Cultured in Vortex Flow with Swinging Plate in Vitro

    Directory of Open Access Journals (Sweden)

    Shigehiro Hashimoto

    2011-06-01

    Full Text Available An effect of flow on cell culture has been studied in vitro. A silicone disk was placed in the center of culture dish of 52 mm internal diameter to make a doughnut-shaped canal. The dish was placed on a tilted plate, which rotates to make a vortex flow around the silicone disk with a swing motion. Variations were made on the diameter (20 mm, 30 mm, and 40 mm of the silicone disk and the rotational speed (2.1 rad/sec, 5.2 rad/sec of the swinging plate, which tilts with 0.1 rad from the horizontal plane. Five kinds of cells were cultured in the vortex flow of Dulbecco’s Modified Eagle’s Medium for seven days: C2C12 (mouse myoblast, L6 (rat skeletal muscle cell, A7r5 (rat aortic smooth muscle cell, CS-2P2-C75 (primary normal porcine aortic endothelial cell, and L929 (mouse fibroblast. The experiments show the following results. The orientation of cells depends on flow and on kinds of cells. A7r5 and CS-2P2-C75 line along the streamline of the flow. C2C12 and L6 adhere along the direction of the flow in the first stage, and tilt to the perpendicular direction to the flow differentiating to myotubes with fusion in the second stage.

  3. Spectral Unmixing Plate Reader: High-Throughput, High-Precision FRET Assays in Living Cells.

    Science.gov (United States)

    Schaaf, Tory M; Peterson, Kurt C; Grant, Benjamin D; Thomas, David D; Gillispie, Gregory D

    2017-03-01

    We have developed a microplate reader that records a complete high-quality fluorescence emission spectrum on a well-by-well basis under true high-throughput screening (HTS) conditions. The read time for an entire 384-well plate is less than 3 min. This instrument is particularly well suited for assays based on fluorescence resonance energy transfer (FRET). Intramolecular protein biosensors with genetically encoded green fluorescent protein (GFP) donor and red fluorescent protein (RFP) acceptor tags at positions sensitive to structural changes were stably expressed and studied in living HEK cells. Accurate quantitation of FRET was achieved by decomposing each observed spectrum into a linear combination of four component (basis) spectra (GFP emission, RFP emission, water Raman, and cell autofluorescence). Excitation and detection are both conducted from the top, allowing for thermoelectric control of the sample temperature from below. This spectral unmixing plate reader (SUPR) delivers an unprecedented combination of speed, precision, and accuracy for studying ensemble-averaged FRET in living cells. It complements our previously reported fluorescence lifetime plate reader, which offers the feature of resolving multiple FRET populations within the ensemble. The combination of these two direct waveform-recording technologies greatly enhances the precision and information content for HTS in drug discovery.

  4. An aerator for brain slice experiments in individual cell culture plate wells.

    Science.gov (United States)

    Dorris, David M; Hauser, Caitlin A; Minnehan, Caitlin E; Meitzen, John

    2014-12-30

    Ex vivo acute living brain slices are a broadly employed and powerful experimental preparation. Most new technology regarding this tissue has involved the chamber used when performing electrophysiological experiments. Alternatively we instead focus on the creation of a simple, versatile aerator designed to allow maintenance and manipulation of acute brain slices and potentially other tissue in a multi-well cell culture plate. Here we present an easily manufactured aerator designed to fit into a 24-well cell culture plate. It features a nylon mesh and a single microhole to enable gas delivery without compromising tissue stability. The aerator is designed to be individually controlled, allowing both high throughput and single well experiments. The aerator was validated by testing material leach, dissolved oxygen delivery, brain slice viability and neuronal electrophysiology. Example experiments are also presented, including a test of whether β1-adrenergic receptor activation regulates gene expression in ex vivo dorsal striatum using qPCR. Key differences include enhanced control over gas delivery to individual wells containing brain slices, decreased necessary volume, a sample restraint to reduce movement artifacts, the potential to be sterilized, the avoidance of materials that absorb water and small biological molecules, minimal production costs, and increased experimental throughput. This new aerator is of high utility and will be useful for experiments involving brain slices and other potentially tissue samples in 24-well cell culture plates. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. High-content imaging with micropatterned multiwell plates reveals influence of cell geometry and cytoskeleton on chromatin dynamics.

    Science.gov (United States)

    Harkness, Ty; McNulty, Jason D; Prestil, Ryan; Seymour, Stephanie K; Klann, Tyler; Murrell, Michael; Ashton, Randolph S; Saha, Krishanu

    2015-10-01

    Understanding the mechanisms underpinning cellular responses to microenvironmental cues requires tight control not only of the complex milieu of soluble signaling factors, extracellular matrix (ECM) connections and cell-cell contacts within cell culture, but also of the biophysics of human cells. Advances in biomaterial fabrication technologies have recently facilitated detailed examination of cellular biophysics and revealed that constraints on cell geometry arising from the cellular microenvironment influence a wide variety of human cell behaviors. Here, we create an in vitro platform capable of precise and independent control of biochemical and biophysical microenvironmental cues by adapting microcontact printing technology into the format of standard six- to 96-well plates to create MicroContact Printed Well Plates (μCP Well Plates). Automated high-content imaging of human cells seeded on μCP Well Plates revealed tight, highly consistent control of single-cell geometry, cytoskeletal organization, and nuclear elongation. Detailed subcellular imaging of the actin cytoskeleton and chromatin within live human fibroblasts on μCP Well Plates was then used to describe a new relationship between cellular geometry and chromatin dynamics. In summary, the μCP Well Plate platform is an enabling high-content screening technology for human cell biology and cellular engineering efforts that seek to identify key biochemical and biophysical cues in the cellular microenvironment.

  6. Floor plate-derived sonic hedgehog regulates glial and ependymal cell fates in the developing spinal cord.

    Science.gov (United States)

    Yu, Kwanha; McGlynn, Sean; Matise, Michael P

    2013-04-01

    Cell fate specification in the CNS is controlled by the secreted morphogen sonic hedgehog (Shh). At spinal cord levels, Shh produced by both the notochord and floor plate (FP) diffuses dorsally to organize patterned gene expression in dividing neural and glial progenitors. Despite the fact that two discrete sources of Shh are involved in this process, the individual contribution of the FP, the only intrinsic source of Shh throughout both neurogenesis and gliogenesis, has not been clearly defined. Here, we have used conditional mutagenesis approaches in mice to selectively inactivate Shh in the FP (Shh(FP)) while allowing expression to persist in the notochord, which underlies the neural tube during neurogenesis but not gliogenesis. We also inactivated Smo, the common Hh receptor, in neural tube progenitors. Our findings confirm and extend prior studies suggesting an important requirement for Shh(FP) in specifying oligodendrocyte cell fates via repression of Gli3 in progenitors. Our studies also uncover a connection between embryonic Shh signaling and astrocyte-mediated reactive gliosis in adults, raising the possibility that this pathway is involved in the development of the most common cell type in the CNS. Finally, we find that intrinsic spinal cord Shh signaling is required for the proper formation of the ependymal zone, the epithelial cell lining of the central canal that is also an adult stem cell niche. Together, our studies identify a crucial late embryonic role for Shh(FP) in regulating the specification and differentiation of glial and epithelial cells in the mouse spinal cord.

  7. New process for fuel cell fabrication. 3D screen printing of metal bipolar plates; Neues Verfahren zur Brennstoffzellenfertigung. 3D-Siebdruck von metallischen Bipolarplatten

    Energy Technology Data Exchange (ETDEWEB)

    Studnitzky, Thomas [Fraunhofer-Institut fuer Fertigungstechnik und Angewandte Materialforschung (IFAM), Dresden (Germany); Helm, Peter; Heinzel, Angelika [Zentrum fuer BrennstoffzellenTechnik GmbH (ZBT), Duisburg (Germany)

    2011-01-15

    Minimization of space requirements, weight, and production cost is one of the key preconditions for successful launching of the polymer electrolyte membrane fuel cell (PEM). In the stacks constructed from single PEM cells, the bipolar plate is a central component. It determines the weight and volume of the stack and accounts for more than 30 percent of the overall cost, depending on the fabrication process. It is therefore important for producers of fuel cells to develop a process that combines free design, high functionality and low cost in serial production.

  8. Calculations to compare different ways of modelling the plate geometry cells of the Zebra fast critical assembly, MZA

    Energy Technology Data Exchange (ETDEWEB)

    Rowlands, John, E-mail: rowlandsjl@aol.com

    2009-03-15

    The core region cells of the Zebra fast critical assembly MZA comprise 14 plates in a square steel tube, with 12 cells being stacked axially to form the core section of the assembly. The cells can be modelled in different levels of detail, ranging from a three-dimensional representation in which the core (The word core is used to describe both the region of a plate containing the main material, such as plutonium, UO{sub 2} or sodium, and the region of the assembly containing fissile material cells.) and canning regions of the plates and the void gaps between the edges of the plates and the steel tube, and between tubes, are represented. Simplified models include a three-dimensional representation in which the void regions are combined with the tube material. A further simplified three-dimensional model, called the MURAL model, represents the core regions of the plates but homogenises the canning, tube material and void regions. Two types of one-dimensional slab geometry model are found in the literature, one in which the materials are homogenised within each of the three axial slab regions of a canned plate (plate core and upper and lower canning regions) and a further simplified version in which the plate is modelled as a single region, the compositions being averaged over the whole thickness of the plate, comprising the plate core material, the canning and the tube material. MONK Monte Carlo calculations have been made for each of these models, and also for the fully homogenised cells, and the k-effective values, core sodium void reactivities and reaction rate ratios are compared.

  9. Apical accumulation of MARCKS in neural plate cells during neurulation in the chick embryo

    Directory of Open Access Journals (Sweden)

    Arruti Cristina

    2001-04-01

    Full Text Available Abstract Background The neural tube is formed by morphogenetic movements largely dependent on cytoskeletal dynamics. Actin and many of its associated proteins have been proposed as important mediators of neurulation. For instance, mice deficient in MARCKS, an actin cross-linking membrane-associated protein that is regulated by PKC and other kinases, present severe developmental defects, including failure of cranial neural tube closure. Results To determine the distribution of MARCKS, and its possible relationships with actin during neurulation, chick embryos were transversely sectioned and double labeled with an anti-MARCKS polyclonal antibody and phalloidin. In the neural plate, MARCKS was found ubiquitously distributed at the periphery of the cells, being conspicuously accumulated in the apical cell region, in close proximity to the apical actin meshwork. This asymmetric distribution was particularly noticeable during the bending process. After the closure of the neural tube, the apically accumulated MARCKS disappeared, and this cell region became analogous to the other peripheral cell zones in its MARCKS content. Actin did not display analogous variations, remaining highly concentrated at the cell subapical territory. The transient apical accumulation of MARCKS was found throughout the neural tube axis. The analysis of another epithelial bending movement, during the formation of the lens vesicle, revealed an identical phenomenon. Conclusions MARCKS is transiently accumulated at the apical region of neural plate and lens placode cells during processes of bending. This asymmetric subcellular distribution of MARCKS starts before the onset of neural plate bending. These results suggest possible upstream regulatory actions of MARCKS on some functions of the actin subapical meshwork.

  10. Targeting development of incretin-producing cells increases insulin secretion

    DEFF Research Database (Denmark)

    Petersen, Natalia; Reimann, Frank; van Es, Johan H

    2015-01-01

    systems and augmented glucose-stimulated GLP-1 secretion. In a high-fat diet-fed mouse model of impaired glucose tolerance and type 2 diabetes, dibenzazepine administration increased L cell numbers in the intestine, improved the early insulin response to glucose, and restored glucose tolerance......Glucagon-like peptide-1-based (GLP-1-based) therapies improve glycemic control in patients with type 2 diabetes. While these agents augment insulin secretion, they do not mimic the physiological meal-related rise and fall of GLP-1 concentrations. Here, we tested the hypothesis that increasing...... the number of intestinal L cells, which produce GLP-1, is an alternative strategy to augment insulin responses and improve glucose tolerance. Blocking the NOTCH signaling pathway with the γ-secretase inhibitor dibenzazepine increased the number of L cells in intestinal organoid-based mouse and human culture...

  11. Growth hormone induces multiplication of the slowly cycling germinal cells of the rat tibial growth plate.

    OpenAIRE

    Ohlsson, C.; Nilsson, A; Isaksson, O; Lindahl, A

    1992-01-01

    To study the effect of locally infused growth hormone (GH) or insulin-like growth factor I(IGF-I) on slowly cycling cells in the germinal cell layer of the tibial growth plate, osmotic minipumps delivering 14.3 microCi of [3H]thymidine per day were implanted s.c. into hypophysectomized rats, and GH (1 microgram) or IGF-I (10 micrograms) was injected daily through a cannula implanted in the proximal tibia. The opposite leg served as a control. After 12 days of treatment, the osmotic minipumps ...

  12. On the use of plate-type normal pressure cells in silos

    DEFF Research Database (Denmark)

    Ramirez, Alvaro; Nielsen, Jørgen; Ayuga, F.

    2010-01-01

    Pressure cells are measuring devices commonly used in silo research to study loads exerted by a granular material stored against a silo wall. The design of normal pressure cells for use in an experimental silo research project is critical, mainly because measuring errors complicate...... the interpretation of results. Once the cells have been delivered from the manufacturer to the researcher, they should be calibrated and validated with reference to the measurement of pressure from a granular material against a silo wall. Two related papers deal with a specific plate-type normal pressure cell...... for use in an installation of three full-scale steel silos with different hopper eccentricities (concentric, half-eccentric and full-eccentric) as part of a silo research project. It was found to be necessary to validate the performance of the cells when measuring pressures in the silos in order to arrive...

  13. A BMP regulatory network controls ectodermal cell fate decisions at the neural plate border.

    Science.gov (United States)

    Reichert, Sabine; Randall, Rebecca A; Hill, Caroline S

    2013-11-01

    During ectodermal patterning the neural crest and preplacodal ectoderm are specified in adjacent domains at the neural plate border. BMP signalling is required for specification of both tissues, but how it is spatially and temporally regulated to achieve this is not understood. Here, using a transgenic zebrafish BMP reporter line in conjunction with double-fluorescent in situ hybridisation, we show that, at the beginning of neurulation, the ventral-to-dorsal gradient of BMP activity evolves into two distinct domains at the neural plate border: one coinciding with the neural crest and the other abutting the epidermis. In between is a region devoid of BMP activity, which is specified as the preplacodal ectoderm. We identify the ligands required for these domains of BMP activity. We show that the BMP-interacting protein Crossveinless 2 is expressed in the BMP activity domains and is under the control of BMP signalling. We establish that Crossveinless 2 functions at this time in a positive-feedback loop to locally enhance BMP activity, and show that it is required for neural crest fate. We further demonstrate that the Distal-less transcription factors Dlx3b and Dlx4b, which are expressed in the preplacodal ectoderm, are required for the expression of a cell-autonomous BMP inhibitor, Bambi-b, which can explain the specific absence of BMP activity in the preplacodal ectoderm. Taken together, our data define a BMP regulatory network that controls cell fate decisions at the neural plate border.

  14. Interlaminar and ductile characteristics of carbon fibers-reinforced plastics produced by nanoscaled electroless nickel plating on carbon fiber surfaces.

    Science.gov (United States)

    Park, Soo-Jin; Jang, Yu-Sin; Rhee, Kyong-Yop

    2002-01-15

    In this work, a new method based on nanoscaled Ni-P alloy coating on carbon fiber surfaces is proposed for the improvement of interfacial properties between fibers and epoxy matrix in a composite system. Fiber surfaces and the mechanical interfacial properties of composites were characterized by atomic absorption spectrophotometer (AAS), scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS), interlaminar shear strength (ILSS), and impact strength. Experimental results showed that the O(1s)/C(1s) ratio or Ni and P amounts had been increased as the electroless nickel plating proceeded; the ILSS had also been slightly improved. The impact properties were significantly improved in the presence of Ni-P alloy on carbon fiber surfaces, increasing the ductility of the composites. This was probably due to the effect of substituted Ni-P alloy, leading to an increase of the resistance to the deformation and the crack initiation of the epoxy system.

  15. Putative porcine embryonic stem cell lines derived from aggregated four-celled cloned embryos produced by oocyte bisection cloning.

    Science.gov (United States)

    Siriboon, Chawalit; Lin, Yu-Hsuan; Kere, Michel; Chen, Chun-Da; Chen, Lih-Ren; Chen, Chien-Hong; Tu, Ching-Fu; Lo, Neng-Wen; Ju, Jyh-Cherng

    2015-01-01

    We attempted to isolate ES cell lines using inner cell masses from high-quality cloned porcine blastocysts. After being seeded onto feeders, embryos had better (P cloned embryos (62.8, 42.6 and 12.8% vs. 76.2, 55.2 and 26.2%, respectively) compared to the non-aggregated group (41.6, 23.4 and 3.9%). Effects of feeder types (STO vs. MEF) and serum sources (FBS vs. KSR) on extraction of cloned embryo-derived porcine ES cells were examined. More (17.1%) ntES cell lines over Passage 3 were generated in the MEF/KSR group. However, ntES cells cultured in KSR-supplemented medium had a low proliferation rate with defective morphology, and eventually underwent differentiation or apoptosis subsequently. Approximately 26.1, 22.7 and 35.7% of primary colonies were formed after plating embryos in DMEM, DMEM/F12 and α-MEM media, respectively. Survival rates of ntES cells cultured in α-MEM, DMEM and DMEM/F12 were 16.7, 4.3 and 6.8%, respectively (P > 0.05). We further examined the beneficial effect of TSA treatment of 3× aggregated cloned embryos on establishment of ntES cell lines. Primary colony numbers and survival rates of ntES cells beyond passage 3 were higher (P cloned embryos produced by embryo aggregation, and optimized the ES cell culture system suitable for establishing and maintaining ntES cell lines in undifferentiated state.

  16. Optimization of the polypyrrole-coating parameters for proton exchange membrane fuel cell bipolar plates using the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Northwood, Derek O. [Department of Mechanical, Automotive, and Materials Engineering, University of Windsor, 401 Sunset Avenue, Windsor, Ontario (Canada)

    2008-10-15

    In order to overcome the high price, weight and volume of non-porous graphite bipolar plates, metallic bipolar plates are being investigated as a substitute material. However, metallic materials can corrode under proton exchange membrane fuel cell (PEMFC) working conditions, leading to a degradation in the performance of the membrane. Previous work had shown that a polypyrrole coating on SS316L can significantly increase the corrosion resistance of the base material. In this study, a Taguchi design of experiment method was used to optimize the process parameters for the polypyrrole coating so as to produce the maximum corrosion resistance. Potentiodynamic and potentiostatic tests were used to determine the corrosion resistance of the polypyrrole-coated SS316L. Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) was used to characterize the coating thickness and coating appearance. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to determine the metal ion concentration in the solution after corrosion. The interfacial contact resistance of SS316L with carbon paper was measured both before and after coating with polypyrrole. (author)

  17. The preparation technique optimization of epoxy/compressed expanded graphite composite bipolar plates for proton exchange membrane fuel cells

    Science.gov (United States)

    Du, Chao; Ming, Pingwen; Hou, Ming; Fu, Jie; Fu, Yunfeng; Luo, Xiaokuan; Shen, Qiang; Shao, Zhigang; Yi, Baolian

    Vacuum resin impregnation method has been used to prepare polymer/compressed expanded graphite (CEG) composite bipolar plates for proton exchange membrane fuel cells (PEMFCs). In this research, three different preparation techniques of the epoxy/CEG composite bipolar plate (Compression-Impregnation method, Impregnation-Compression method and Compression-Impregnation-Compression method) are optimized by the physical properties of the composite bipolar plates. The optimum conditions and the advantages/disadvantages of the different techniques are discussed respectively. Although having different characteristics, bipolar plates obtained by these three techniques can all meet the demands of PEMFC bipolar plates as long as the optimum conditions are selected. The Compression-Impregnation-Compression method is shown to be the optimum method because of the outstanding properties of the bipolar plates. Besides, the cell assembled with these optimum composite bipolar plates shows excellent stability after 200 h durability testing. Therefore the composite prepared by vacuum resin impregnation method is a promising candidate for bipolar plate materials in PEMFCs.

  18. Insulin-producing cells from embryonic stem cells rescues hyperglycemia via intra-spleen migration.

    Science.gov (United States)

    Ren, Meng; Shang, Changzhen; Zhong, Xiaomei; Guo, Ruomi; Lao, Guojuan; Wang, Xiaoyi; Cheng, Hua; Min, Jun; Yan, Li; Shen, Jun

    2014-12-23

    Implantation of embryonic stem cells (ESC)-derived insulin-producing cells has been extensively investigated for treatment of diabetes in animal models. However, the in vivo behavior and migration of transplanted cells in diabetic models remains unclear. Here we investigated the location and migration of insulin-producing cells labeled with superparamagnetic iron oxide (SPIO) using a dynamic MRI tracking method. SPIO labeled cells showed hypointense signal under the kidney subcapsules of diabetic mice on MRI, and faded gradually over the visiting time. However, new hypointense signal appeared in the spleen 1 week after transplantation, and became obvious with the time prolongation. Further histological examination proved the immigrated cells were insulin and C-peptide positive cells which were evenly distributed throughout the spleen. These intra-spleen insulin-producing cells maintained their protective effects against hyperglycemia in vivo, and these effects were reversed upon spleen removal. Transplantation of insulin-producing cells through spleen acquired an earlier blood glucose control as compared with that through kidney subcapsules. In summary, our data demonstrate that insulin-producing cells transplanted through kidney subcapsules were not located in situ but migrated into spleen, and rescues hyperglycemia in diabetic models. MRI may provide a novel tracking method for preclinical cell transplantation therapy of diabetes continuously and non-invasively.

  19. The Generation of Human Induced Pluripotent Stem Cells from Blood Cells: An Efficient Protocol Using Serial Plating of Reprogrammed Cells by Centrifugation

    Directory of Open Access Journals (Sweden)

    Youngkyun Kim

    2016-01-01

    Full Text Available Human induced pluripotent stem cells (hiPSCs have demonstrated great potential for differentiation into diverse tissues. We report a straightforward and highly efficient method for the generation of iPSCs from PBMCs. By plating the cells serially to a newly coated plate by centrifugation, this protocol provides multiple healthy iPSC colonies even from a small number of PBMCs. The generated iPSCs expressed pluripotent markers and differentiated into all three germ layer lineages. The protocol can also be used with umbilical cord blood mononuclear cells (CBMCs. In this study, we present a simple and efficient protocol that improved the yield of iPSCs from floating cells such as PBMCs and CBMCs by serial plating and centrifugation.

  20. The Generation of Human Induced Pluripotent Stem Cells from Blood Cells: An Efficient Protocol Using Serial Plating of Reprogrammed Cells by Centrifugation.

    Science.gov (United States)

    Kim, Youngkyun; Rim, Yeri Alice; Yi, Hyoju; Park, Narae; Park, Sung-Hwan; Ju, Ji Hyeon

    2016-01-01

    Human induced pluripotent stem cells (hiPSCs) have demonstrated great potential for differentiation into diverse tissues. We report a straightforward and highly efficient method for the generation of iPSCs from PBMCs. By plating the cells serially to a newly coated plate by centrifugation, this protocol provides multiple healthy iPSC colonies even from a small number of PBMCs. The generated iPSCs expressed pluripotent markers and differentiated into all three germ layer lineages. The protocol can also be used with umbilical cord blood mononuclear cells (CBMCs). In this study, we present a simple and efficient protocol that improved the yield of iPSCs from floating cells such as PBMCs and CBMCs by serial plating and centrifugation.

  1. Human B cells produce chemokine CXCL10 in the presence of Mycobacterium tuberculosis specific T cells

    DEFF Research Database (Denmark)

    Hoff, Soren T; Salman, Ahmed M; Ruhwald, Morten

    2015-01-01

    BACKGROUND: The role of B cells in human host response to Mycobacterium tuberculosis (Mtb) infection is still controversial, but recent evidence suggest that B cell follicle like structures within the lung may influence host responses through regulation of the local cytokine environment....... A candidate for such regulation could be the chemokine CXCL10. CXCL10 is mainly produced by human monocytes, but a few reports have also found CXCL10 production by human B cells. The objective of this study was to investigate CXCL10 production by human B cells in response to in vitro stimulation with Mtb...... antigens. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed human blood samples from 30 volunteer donors using multiparameter flow cytometry, and identified a subgroup of B cells producing CXCL10 in response to in vitro stimulation with antigens. T cells did not produce CXCL10, but CXCL10 production by B cells...

  2. Monopolar fuel cell stack coupled together without use of top or bottom cover plates or tie rods

    Science.gov (United States)

    Narayanan, Sekharipuram R. (Inventor); Valdez, Thomas I. (Inventor)

    2009-01-01

    A monopolar fuel cell stack comprises a plurality of sealed unit cells coupled together. Each unit cell comprises two outer cathodes adjacent to corresponding membrane electrode assemblies and a center anode plate. An inlet and outlet manifold are coupled to the anode plate and communicate with a channel therein. Fuel flows from the inlet manifold through the channel in contact with the anode plate and flows out through the outlet manifold. The inlet and outlet manifolds are arranged to couple to the inlet and outlet manifolds respectively of an adjacent one of the plurality of unit cells to permit fuel flow in common into all of the inlet manifolds of the plurality of the unit cells when coupled together in a stack and out of all of the outlet manifolds of the plurality of unit cells when coupled together in a stack.

  3. Differentiation of dermis-derived multipotent cells into insulin-producing pancreatic cells in vitro

    Institute of Scientific and Technical Information of China (English)

    Chun-Meng Shi; Tian-Min Cheng

    2004-01-01

    AIM: To observe the plasticity of whether dermis-derived multipotent cells to differentiate into insulin-producing pancreatic cells in vitro.METHODS: A donal population of dermis-derived multipotent stem cells (DMCs) from newborn rat with the capacity to produce osteocytes, chondrocytes, adipocytes and neurons was used. The gene expression of cultured DMCs was assessed by DNA microarray using rat RGU34A gene expression probe arrays. DMCs were further cultured in the presence of insulin complex components (Insulintransferrin-selenium, ITS) to observe whether DMCs could be induced into insulin-producing pancreatic cells in vitro.RESULTS: DNA microarray analysis showed that cultured DMCs simultaneously expressed several genes associated with pancreatic cell, neural cell, epithelial cell and hepatocyte,widening its transcriptomic repertoire. When cultured in the specific induction medium containing ITS for pancreatic cells, DMCs differentiated into epithelioid cells that were positive for insulin detected by immunohistochemistry.CONCLUSION: Our data indicate that dermal multipotent cells may serve as a source of stem/progenitor cells for insulin-producing pancreatic cells.

  4. Hypertrophic chondrocytes in the rabbit growth plate can proliferate and differentiate into osteogenic cells when capillary invasion is interposed by a membrane filter.

    Directory of Open Access Journals (Sweden)

    Tetsuya Enishi

    Full Text Available The fate of hypertrophic chondrocytes during endochondral ossification remains controversial. It has long been thought that the calcified cartilage is invaded by blood vessels and that new bone is deposited on the surface of the eroded cartilage by newly arrived cells. The present study was designed to determine whether hypertrophic chondrocytes were destined to die or could survive to participate in new bone formation. In a rabbit experiment, a membrane filter with a pore size of 1 µm was inserted in the middle of the hypertrophic zone of the distal growth plate of ulna. In 33 of 37 animals, vascular invasion was successfully interposed by the membrane filter. During 8 days, the cartilage growth plate was enlarged, making the thickness 3-fold greater than that of the nonoperated control side. Histological examination demonstrated that the hypertrophic zone was exclusively elongated. At the terminal end of the growth plate, hypertrophic chondrocytes extruded from their territorial matrix into the open cavity on the surface of the membrane filter. The progenies of hypertrophic chondrocytes (PHCs were PCNA positive and caspase-3 negative. In situ hybridization studies demonstrated that PHCs did not express cartilage matrix proteins anymore but expressed bone matrix proteins. Immunohistochemical studies also demonstrated that the new matrix produced by PHCs contained type I collagen, osteonectin, and osteocalcin. Based on these results, we concluded that hypertrophic chondrocytes switched into bone-forming cells after vascular invasion was interposed in the normal growth plate.

  5. Microbes produce nanobacteria-like structures, avoiding cell entombment

    Science.gov (United States)

    Bontognali, Tomaso R. R.; Vasconcelos, Crisógono; Warthmann, Rolf J.; Dupraz, Christophe; Bernasconi, Stefano M.; McKenzie, Judith A.

    2008-08-01

    Microsedimentary structures referred to as nanobacteria-likeparticles were described from modern carbonate environments,where they form in close spatial association with sulfate-reducingbacteria (SRB). However, the exact mechanism of their formation,as well as their paleontological significance, remains controversial.Here we report on an investigation of microbe-mineral interactionsin experimentally produced carbonate globules. The experimentswere carried out under anoxic conditions at 30 °C with Desulfovibriobrasiliensis, a SRB known to mediate dolomite formation. Weobserved that extracellular polymeric substances (EPS) secretedby the microbial community play a key role in the mineralizationprocess. Nanobacteria-like particles represent the early stageof carbonate nucleation within the EPS, which progressivelyevolve to larger globules displaying a grainy texture. We excludedthe possibilities that these structures are fossils of nanobacteria,dissolution surfaces, or artifacts created during sample preparation.D. brasiliensis cells are predominantly located outside of theEPS aggregates where mineral growth takes place. As a result,they remain mobile and are rarely entombed within the mineral.This self-preservation behavior may not be limited to D. brasiliensis.Other microbes may produce, or may have produced during thegeological past, biogenic minerals through a similar process.Mineralization within EPS explains why microbial relics arenot necessarily present in biogenic carbonates.

  6. Mathematical model of a plate fin heat exchanger operating under solid oxide fuel cell working conditions

    Science.gov (United States)

    Kaniowski, Robert; Poniewski, Mieczysław

    2013-12-01

    Heat exchangers of different types find application in power systems based on solid oxide fuel cells (SOFC). Compact plate fin heat exchangers are typically found to perfectly fit systems with power output under 5 kWel. Micro-combined heat and power (micro-CHP) units with solid oxide fuel cells can exhibit high electrical and overall efficiencies, exceeding 85%, respectively. These values can be achieved only when high thermal integration of a system is assured. Selection and sizing of heat exchangers play a crucial role and should be done with caution. Moreover, performance of heat exchangers under variable operating conditions can strongly influence efficiency of the complete system. For that reason, it becomes important to develop high fidelity mathematical models allowing evaluation of heat exchangers under modified operating conditions, in high temperature regimes. Prediction of pressure and temperatures drops at the exit of cold and hot sides are important for system-level studies. Paper presents dedicated mathematical model used for evaluation of a plate fin heat exchanger, operating as a part of micro-CHP unit with solid oxide fuel cells.

  7. Miniaturized polymer electrolyte fuel cell (PEFC) stack using micro structured bipolar plate

    Energy Technology Data Exchange (ETDEWEB)

    Veziridis, Z.; Scherer, G.G.; Marmy, Ch.; Glaus, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    In Polymer Electrolyte Fuel Cell (PEFC) technology the reducing of volume and mass of the fuel cell stack and the improvement of catalyst utilization are of great interest. These parameters affect applicability and system cost. In this work we present an alternative way for reducing the stack volume by combining gas distribution and catalytic active area in one plate. Micro machined glassy carbon electrodes serve as support material for the platinum catalyst, as well as gas distributor at the same time. A comparison of these electrodes with conventional platinum-black gas diffusion electrodes under fuel cell conditions shows that the new system is a promising electrode type for enhanced power density and catalyst utilization. (author) 3 figs., 5 refs.

  8. Low-cost zinc-plated photoanode for fabric-type dye-sensitized solar cells

    Science.gov (United States)

    Kong, Lingfeng; Bao, Yunna; Guo, Wanwan; Cheng, Li; Du, Jun; Liu, Renlong; Wang, Yundong; Fan, Xing; Tao, Changyuan

    2016-02-01

    Fabric-type flexible solar cells have been recently proposed as a very promising power source for wearable electronics. To increase the photocurrent of fabric-type flexible solar cells, low-cost zinc-plated wire and mesh photoanodes are assembled for the first time through a mild wet process. Given the protection of the compact protection layer, the DSSC device could benefit from the low work function of Zn and self-repairing behavior on the Zn/ZnO interface. An evident current increase by ∼6 mA/cm2 could be observed after coating a layer of metal Zn on various metal substrates, such as traditional stainless steel wire. Given the self-repairing behavior on Zn/ZnO interface, the Zn layer can help to improve the interfacial carrier transfer, leading to better photovoltaic performance, for both liquid-type and solid-type cells.

  9. Hyperspectral imaging for detection of non-O157 Shiga-toxin producing Escherichia coli (STEC) serogroups on spread plates of mixed cultures

    Science.gov (United States)

    Yoon, Seung Chul; Windham, William R.; Ladely, Scott; Heitschmidt, Gerald W.; Lawrence, Kurt C.; Park, Bosoon; Narang, Neelam; Cray, William C.

    2012-05-01

    We investigated the feasibility of visible and near-infrared (VNIR) hyperspectral imaging for rapid presumptive-positive screening of six representative non-O157 Shiga-toxin producing Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145) on spread plates of mixed cultures. Although the traditional culture method is still the "gold standard" for presumptive-positive pathogen screening, it is time-consuming, labor-intensive, not effective in testing large amount of food samples, and cannot completely prevent unwanted background microflora from growing together with target microorganisms on agar media. A previous study was performed using the data obtained from pure cultures individually inoculated on spot and/or spread plates in order to develop multivariate classification models differentiating each colony of the six non-O157 STEC serogroups and to optimize the models in terms of parameters. This study dealt with the validation of the trained and optimized models with a test set of new independent samples obtained from colonies on spread plates of mixed cultures. A new validation protocol appropriate to a hyperspectral imaging study for mixed cultures was developed. One imaging experiment with colonies obtained from two serial dilutions was performed. A total of six agar plates were prepared, where O45, O111 and O121 serogroups were inoculated into all six plates and each of O45, O103 and O145 serogroups was added into the mixture of the three common bacterial cultures. The number of colonies grown after 24-h incubation was 331 and the number of pixels associated with the grown colonies was 16,379. The best model found from this validation study was based on pre-processing with standard normal variate and detrending (SNVD), first derivative, spectral smoothing, and k-nearest neighbor classification (kNN, k=3) of scores in the principal component subspace spanned by 6 principal components. The independent testing results showed 95% overall

  10. Human Beta Cells Produce and Release Serotonin to Inhibit Glucagon Secretion from Alpha Cells

    OpenAIRE

    Joana Almaça; Judith Molina; Danusa Menegaz; Pronin, Alexey N.; Alejandro Tamayo; Vladlen Slepak; Per-Olof Berggren; Alejandro Caicedo

    2016-01-01

    In the pancreatic islet, serotonin is an autocrine signal increasing beta cell mass during metabolic challenges such as those associated with pregnancy or high-fat diet. It is still unclear whether serotonin is relevant for regular islet physiology and hormone secretion. Here, we show that human beta cells produce and secrete serotonin when stimulated with increases in glucose concentration. Serotonin secretion from beta cells decreases cyclic AMP (cAMP) levels in neighboring alpha cells via ...

  11. Evaluation of materials for bipolar plates in simulated PEM fuel-cell cathodic environments

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, S.V.; Belmonte, M.R.; Moron, L.E.; Torres, J.; Orozco, G. [Centro de Investigacion y Desarrollo Technologico en Electroquimica S.C. Parcque Sanfandila, Queretaro (Mexico); Perez-Quiroz, J.T. [Mexican Transport Inst., Queretaro (Mexico); Cortes, M. A. [Mexican Petroleum Inst., Mexico City (Mexico)

    2008-04-15

    The bipolar plates in proton exchange membrane fuel cells (PEMFC) are exposed to an oxidizing environment on the cathodic side, and therefore are susceptible to corrosion. Corrosion resistant materials are needed for the bipolar plates in order to improve the lifespan of fuel cells. This article described a study in which a molybdenum (Mo) coating was deposited over austenitic stainless steel 316 and carbon steel as substrates in order to evaluate the resulting surfaces with respect to their corrosion resistance in simulated anodic and cathodic PEMFC environments. The molybdenum oxide films were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The article presented the experiment and discussed the results of the corrosion behaviour of coated stainless steel. In general, the electrochemical characterization of bare materials and coated steel consisted of slow potentiodynamic polarization curves followed by a constant potential polarization test. The test medium was 0.5M sulfuric acid with additional introduction of oxygen to simulate the cathodic environment. All tests were performed at ambient temperature and at 50 degrees Celsius. The potentiostat used was a Gamry instrument. It was concluded that it is possible to deposit Mo-oxides on steel without using another alloying metal. The preferred substrate for corrosion prevention was found to be an alloy with high chromium content. 24 refs., 4 figs.

  12. The flat-plate plant-microbial fuel cell: the effect of a new design on internal resistances

    Directory of Open Access Journals (Sweden)

    Helder Marjolein

    2012-09-01

    Full Text Available Abstract Due to a growing world population and increasing welfare, energy demand worldwide is increasing. To meet the increasing energy demand in a sustainable way, new technologies are needed. The Plant-Microbial Fuel Cell (P-MFC is a technology that could produce sustainable bio-electricity and help meeting the increasing energy demand. Power output of the P-MFC, however, needs to be increased to make it attractive as a renewable and sustainable energy source. To increase power output of the P-MFC internal resistances need to be reduced. With a flat-plate P-MFC design we tried to minimize internal resistances compared to the previously used tubular P-MFC design. With the flat-plate design current and power density per geometric planting area were increased (from 0.15 A/m2 to 1.6 A/m2 and from 0.22 W/m2 to and 0.44 W/m2as were current and power output per volume (from 7.5 A/m3 to 122 A/m3 and from 1.3 W/m3 to 5.8 W/m3. Internal resistances times volume were decreased, even though internal resistances times membrane surface area were not. Since the membrane in the flat-plate design is placed vertically, membrane surface area per geometric planting area is increased, which allows for lower internal resistances times volume while not decreasing internal resistances times membrane surface area. Anode was split into three different sections on different depths of the system, allowing to calculate internal resistances on different depths. Most electricity was produced where internal resistances were lowest and where most roots were present; in the top section of the system. By measuring electricity production on different depths in the system, electricity production could be linked to root growth. This link offers opportunities for material-reduction in new designs. Concurrent reduction in material use and increase in power output brings the P-MFC a step closer to usable energy density and economic feasibility.

  13. Electrical resistivity and dielectric properties of helical microorganism cells coated with silver by electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Jun, E-mail: jun_cai@buaa.edu.cn [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Lan, Mingming; Zhang, Deyuan; Zhang, Wenqiang [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer We use the microorganism cells as forming templates to fabricate the bio-based conductive particles. Black-Right-Pointing-Pointer The microorganism cells selected as forming templates are Spirulina platens, which are of natural helical shape and high aspect ratio. Black-Right-Pointing-Pointer The sliver-coated Spirulina cells are a kind of lightweight conductive particles. Black-Right-Pointing-Pointer The composites containing sliver-coated Spirulina cells exhibit a lower percolation value. - Abstract: In this paper, microorganism cells (Spirulina platens) were used as forming templates for the fabrication of the helical functional particles by electroless silver plating process. The morphologies and ingredients of the coated Spirulina cells were analyzed with scanning electron microscopy and energy dispersive spectrometer. The crystal structures were characterized by employing the X-ray diffraction. The electrical resistivity and dielectric properties of samples containing different volume faction of sliver-coated Spirulina cells were measured and investigated by four-probe meter and vector network analyzer. The results showed that the Spirulina cells were successfully coated with a uniform silver coating and their initial helical shapes were perfectly kept. The electrical resistivity and dielectric properties of the samples had a strong dependence on the volume content of sliver-coated Spirulina cells and the samples could achieve a low percolation value owing to high aspect ratio and preferable helical shape of Spirulina cells. Furthermore, the conductive mechanism was analyzed with the classic percolation theory, and the values of {phi}{sub c} and t were obtained.

  14. Optimal Design for the Diffusion Plate with Nanoparticles in a Diffusive Solar Cell Window by Mie Scattering Simulation

    Directory of Open Access Journals (Sweden)

    Ruei-Tang Chen

    2013-01-01

    Full Text Available A diffusive solar cell window comprises a diffusion plate with TiO2 nanoparticles sandwiched between two glass layers. It is a simple, inexpensive, easy-to-made, and highly reliable transparent solar energy module. To improve its power generation efficiency as well as maintain indoor natural lighting, we examined the scattering mechanism in the diffusion plate with TiO2 nanoparticles within a diffusive solar cell window by Mie scattering simulations. In this work, a multiwavelength ASAP ray tracing model for a diffusive solar cell window with acceptable accuracy was developed to investigate the influence of the diffusion plate design parameter, mainly concentration of a diffusion plate with determined particle size distribution, on power generation efficiency and color shift of transmitted sun light. A concept of “effective average radius” was proposed to account for the equivalent scattering effect of a size distribution of quasispherical particles. Simulation results demonstrated that both the transmitted light and its correlated color temperature decreased as the concentration increased for a large-size diffusive solar cell window. However, there existed a maximum power generation efficiency at around 160 ppm concentration. The optimal design for a large-size diffusion plate inside a diffusive solar cell window by taking indoor lighting into account was suggested based on the simulation results.

  15. Extrinsic Factors Involved in the Differentiation of Stem Cells into Insulin-Producing Cells: An Overview

    Directory of Open Access Journals (Sweden)

    Rebecca S. Y. Wong

    2011-01-01

    Full Text Available Diabetes mellitus is a chronic disease with many debilitating complications. Treatment of diabetes mellitus mainly revolves around conventional oral hypoglycaemic agents and insulin replacement therapy. Recently, scientists have turned their attention to the generation of insulin-producing cells (IPCs from stem cells of various sources. To date, many types of stem cells of human and animal origins have been successfully turned into IPCs in vitro and have been shown to exert glucose-lowering effect in vivo. However, scientists are still faced with the challenge of producing a sufficient number of IPCs that can in turn produce sufficient insulin for clinical use. A careful choice of stem cells, methods, and extrinsic factors for induction may all be contributing factors to successful production of functional beta-islet like IPCs. It is also important that the mechanism of differentiation and mechanism by which IPCs correct hyperglycaemia are carefully studied before they are used in human subjects.

  16. Effect of Magnetic Field on Adhesion of Muscle Cells to Culture Plate

    Directory of Open Access Journals (Sweden)

    Shigehiro Hashimoto

    2013-08-01

    Full Text Available The effect of a magnetic field on adhesion of cultured muscle cells to the culture plate has been studied in vitro. An experimental system was manufactured to apply a magnetic field to muscle cell culture. The system consists of a couple of solenoid coils, a culture dish of 52 mm internal diameter, and an inverted phase-contrast microscope. The solenoid coil generates the alternating magnetic field of 13 mT of the effective value at a period of 0.01 s with the electric current of the rectangular pulses. C2C12 (Mouse myoblast cell line originated with cross-striated muscle of C3H mouse cells were suspended in Dulbecco's Modified Eagle's Medium. The suspension was poured into the plastic dish placed on the stage of the microscope. The culture dish was exposed to the magnetic field between the solenoid coils at 29 degrees Celsius. For comparative study, a part of the suspension was poured into the same kind of dish without exposure to the magnetic field at 29 degrees Celsius. The number of cells, which adhered to the bottom of the culture dish, was traced according to the time (<130 min during exposure to the alternating magnetic field. The experimental results show that adhesion is accelerated with alternating magnetic field of 13 mT.

  17. Preparation and properties of carbon nanotube/polypropylene nanocomposite bipolar plates for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Liao, Shu-Hang; Yen, Chuan-Yu; Weng, Cheng-Chih; Lin, Yu-Feng; Ma, Chen-Chi M.; Yang, Ching-Hung; Tsai, Ming-Chi; Yen, Ming-Yu; Hsiao, Min-Chien; Lee, Shuo-Jen; Xie, Xiao-Feng; Hsiao, Yi-Hsiu

    This study aims at the fabrication of lightweight and high performance nanocomposite bipolar plates for the application in polymer electrode membrane fuel cells (PEMFCs). The thin nanocomposite bipolar plates (the thickness polypropylene (PP) with different crystallinities including high crystallinity PP (HC-PP), medium crystallinity PP (MC-PP), low crystallinity PP (LC-PP) were prepared to investigate the influence of crystallinity on the dispersion of MWCNTs in PP matrix. The optimum composition of original composite bipolar plates was determined at 80 wt.% graphite content and 20 wt.% PP content based on the measurements of electrical and mechanical properties with various graphite contents. Results also indicate that MWCNTs was dispersed better in LC-PP than other PP owing to enough dispersed regions in nanocomposite bipolar plates. This good MWCNT dispersion of LC-PP would cause better bulk electrical conductivity, mechanical properties and thermal stability of MWCNTs/PP nanocomposite bipolar plates. In the MWCNTs/LC-PP system, the bulk electrical conductivities with various MWCNT contents all exceed 100 S cm -1. The flexural strength of the MWCNTs/LC-PP nanocomposite bipolar plate with 8 phr of MWCNTs was approximately 37% higher than that of the original nanocomposite bipolar plate and the unnotched Izod impact strength of MWCNTs/LC-PP nanocomposite bipolar plates was also increased from 68.32 J m -1 (0 phr) to 81.40 J m -1 (8 phr), increasing 19%. In addition, the coefficient of thermal expansion of MWCNTs/LC-PP nanocomposite bipolar plate was decreased from 32.91 μm m -1 °C -1 (0 phr) to 25.79 μm m -1 °C -1 (8 phr) with the increasing of MWCNT content. The polarization curve of MWCNTs/LC-PP nanocomposite bipolar plate compared with graphite bipolar plate was also evaluated. These results confirm that the addition of MWCNTs in LC-PP leads to a significant improvement on the cell performance of the nanocomposite bipolar plate.

  18. Insulin-producing cells generated from dedifferentiated human pancreatic beta cells expanded in vitro.

    Directory of Open Access Journals (Sweden)

    Holger A Russ

    Full Text Available BACKGROUND: Expansion of beta cells from the limited number of adult human islet donors is an attractive prospect for increasing cell availability for cell therapy of diabetes. However, attempts at expanding human islet cells in tissue culture result in loss of beta-cell phenotype. Using a lineage-tracing approach we provided evidence for massive proliferation of beta-cell-derived (BCD cells within these cultures. Expansion involves dedifferentiation resembling epithelial-mesenchymal transition (EMT. Epigenetic analyses indicate that key beta-cell genes maintain open chromatin structure in expanded BCD cells, although they are not transcribed. Here we investigated whether BCD cells can be redifferentiated into beta-like cells. METHODOLOGY/PRINCIPAL FINDING: Redifferentiation conditions were screened by following activation of an insulin-DsRed2 reporter gene. Redifferentiated cells were characterized for gene expression, insulin content and secretion assays, and presence of secretory vesicles by electron microscopy. BCD cells were induced to redifferentiate by a combination of soluble factors. The redifferentiated cells expressed beta-cell genes, stored insulin in typical secretory vesicles, and released it in response to glucose. The redifferentiation process involved mesenchymal-epithelial transition, as judged by changes in gene expression. Moreover, inhibition of the EMT effector SLUG (SNAI2 using shRNA resulted in stimulation of redifferentiation. Lineage-traced cells also gave rise at a low rate to cells expressing other islet hormones, suggesting transition of BCD cells through an islet progenitor-like stage during redifferentiation. CONCLUSIONS/SIGNIFICANCE: These findings demonstrate for the first time that expanded dedifferentiated beta cells can be induced to redifferentiate in culture. The findings suggest that ex-vivo expansion of adult human islet cells is a promising approach for generation of insulin-producing cells for

  19. Three-dimensional particle-in-cell simulation on gain saturation effect of microchannel plate.

    Science.gov (United States)

    Wang, Qiangqiang; Yuan, Zheng; Cao, Zhurong; Deng, Bo; Chen, Tao; Deng, Keli

    2016-07-01

    We present here the results of the simulation work, using the three-dimensional particle-in-cell method, on the performance of the lead glass microchannel plate under saturated state. We calculated the electron cascade process with different DC bias voltages under both self-consistent condition and non-self-consistent condition. The comparative results have demonstrated that the strong self-consistent field can suppress the cascade process and make the microchannel plate saturated. The simulation results were also compared to the experimental data and good agreement was obtained. The simulation results also show that the electron multiplication process in the channel is accompanied by the buildup process of positive charges in the channel wall. Though the interactions among the secondary electron cloud in the channel, the positive charges in the channel wall, and the external acceleration field can make the electron-surface collision more frequent, the collision energy will be inevitably reduced, thus the electron gain will also be reduced.

  20. Comparative detection of bacterial adhesion to Caco-2 cells with ELISA, radioactivity and plate count methods.

    Science.gov (United States)

    Le Blay, Gwenaëlle; Fliss, Ismaïl; Lacroix, Christophe

    2004-11-01

    Different methods are used to study bacterial adhesion to intestinal epithelial cells, which is an important step in pathogenic infection as well as in probiotic colonization of the intestinal tract. The aim of this study was to compare the ELISA-based method with more conventional plate count and radiolabeling methods for bacterial adhesion detection. An ELISA-based assay was optimized for the detection of Bifidobacterium longum and Escherichia coli O157:H7, which are low and highly adherent bacteria, respectively. In agreement with previous investigations, a percentage of adhesion below 1% was obtained for B. longum with ELISA. However, high nonspecific background and low positive signals were measured due to the use of polyclonal antibodies and the low adhesion capacity with this strain. In contrast, the ELISA-based method developed for E. coli adhesion detected a high adhesion percentage (15%). For this bacterium the three methods tested gave similar results for the highest bacterial concentrations (6.8 Log CFU added bacteria/well). However, differences among methods increased with the addition of decreased bacterial concentration due to different detection thresholds (5.9, 5.6 and 2.9 Log CFU adherent bacteria/well for radioactivity, ELISA and plate count methods, respectively). The ELISA-based method was shown to be a good predictor for bacterial adhesion compared to the radiolabeling method when good quality specific antibodies were used. This technique is convenient and allows handling of numerous samples.

  1. Photothermally induced bromination of carbon/polymer bipolar plate materials for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Schade, Martin; Franzka, Steffen [Fakultät für Chemie, Universität Duisburg-Essen, 45117 Essen (Germany); Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany); Cappuccio, Franco; Peinecke, Volker; Heinzel, Angelika [Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany); Zentrum für BrennstoffzellenTechnik (ZBT), Carl-Benz-Straße 201, 47057 Duisburg (Germany); Hartmann, Nils, E-mail: nils.hartmann@uni-due.de [Fakultät für Chemie, Universität Duisburg-Essen, 45117 Essen (Germany); Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany)

    2015-05-01

    Graphical abstract: - Highlights: • Photothermal laser bromination of carbon/polymer materials is demonstrated. • Using a microfocused laser functionalized domains with diameters of 5 μm and 100 μm and more can be fabricated. • Bromine groups can be transformed in a variety of other chemical functionalities, i.e. amine groups. • Depending on the chemical functionality, the local chemical affinity and wettability is changed. • The routine can be applied to standard bipolar plate materials used for fuel cell applications. - Abstract: A facile photothermal procedure for direct functionalization of carbon/polymer bipolar plate materials is demonstrated. Through irradiation with a microfocused beam of an Ar{sup +}-laser at λ = 514 nm in gaseous bromine and distinct laser powers and pulse lengths local bromination of the carbon/polymer material takes place. At a 1/e spot diameter of 2.1 μm, functionalized surface areas with diameters down to 5 μm are fabricated. In complementary experiments large-area bromination is investigated using an ordinary tungsten lamp. For characterization contact angle goniometry, X-ray photoelectron spectroscopy and electron microscopy in conjunction with labeling techniques are employed. After irradiation bromine groups can easily be substituted by other chemical functionalities, e.g. azide and amine groups. This provides a facile approach in order to fabricate surface patterns and gradient structures with varying wetting characteristics. Mechanistic aspects and prospects of photothermal routines in micropatterning of carbon/polymer materials are discussed.

  2. Patterned Au/poly(dimethylsiloxane) substrate fabricated by chemical plating coupled with electrochemical etching for cell patterning.

    Science.gov (United States)

    Bai, Hai-Jing; Shao, Min-Ling; Gou, Hong-Lei; Xu, Jing-Juan; Chen, Hong-Yuan

    2009-09-01

    In this paper, we present a novel approach for preparing patterned Au/poly(dimethylsiloxane) (PDMS) substrate. Chemical gold plating instead of conventional metal evaporation or sputtering was introduced to achieve a homogeneous gold layer on native PDMS for the first time, which possesses low-cost and simple operation. An electrochemical oxidation reaction accompanied by the coordination of gold and chloride anion was then exploited to etch gold across the region covered by electrolyte. On the basis of such an electrochemical etching, heterogeneous Au/PDMS substrate which has a gold "island" pattern or PDMS dots pattern was fabricated. Hydrogen bubbles which were generated in the etching process due to water electrolysis were used to produce a safe region under the Pt auxiliary electrode. The safe region would protect gold film from etching and lead to the formation of the gold "island" pattern. In virtue of a PDMS stencil with holes array, gold could be etched from the exposed region and take on the PDMS dots pattern which was selected to for protein and cell patterning. This patterned Au/PDMS substrate is very convenient to construct cytophobic and cytophilic regions. Self-assembled surface modification of (1-mercaptoundec-11-yl)hexa(ethylene glycol) on gold and adsorption of fibronectin on PDMS are suitable for effective protein and cell patterning. This patterned Au/PDMS substrate would be a potentially versatile platform for fabricating biosensing arrays.

  3. Overexpression of TIMP-3 in Chondrocytes Produces Transient Reduction in Growth Plate Length but Permanently Reduces Adult Bone Quality and Quantity.

    Science.gov (United States)

    Poulet, Blandine; Liu, Ke; Plumb, Darren; Vo, Phoung; Shah, Mittal; Staines, Katherine; Sampson, Alexandra; Nakamura, Hiroyuki; Nagase, Hideaki; Carriero, Alessandra; Shefelbine, Sandra; Pitsillides, Andrew A; Bou-Gharios, George

    2016-01-01

    Bone development and length relies on the growth plate formation, which is dependent on degradative enzymes such as MMPs. Indeed, deletion of specific members of this enzyme family in mice results in important joint and bone abnormalities, suggesting a role in skeletal development. As such, the control of MMP activity is vital in the complex process of bone formation and growth. We generated a transgenic mouse line to overexpress TIMP3 in mouse chondrocytes using the Col2a1-chondrocyte promoter. This overexpression in cartilage resulted in a transient shortening of growth plate in homozygote mice but bone length was restored at eight weeks of age. However, tibial bone structure and mechanical properties remained compromised. Despite no transgene expression in adult osteoblasts from transgenic mice in vitro, their differentiation capacity was decreased. Neonates, however, did show transgene expression in a subset of bone cells. Our data demonstrate for the first time that transgene function persists in the chondro-osseous lineage continuum and exert influence upon bone quantity and quality.

  4. Surface functionalization of tissue culture polystyrene plates with hydroxyapatite under body fluid conditions and its effect on differentiation behaviors of mesenchymal stem cells.

    Science.gov (United States)

    Iijima, Kazutoshi; Suzuki, Ryo; Iizuka, Ayako; Ueno-Yokohata, Hitomi; Kiyokawa, Nobutaka; Hashizume, Mineo

    2016-11-01

    The surfaces of polystyrene (PS) cell culture plates were functionalized with hydroxyapatite (HAp) under body fluid conditions utilizing protein adsorption layers and a pretreatment with an alternate soaking process (ASP) using solutions containing calcium and phosphate ions. Adsorption layers of human serum albumin (HSA) formed on the surface of each well of commercial 24-well PS plates by solution processes. CaCl2 and K2HPO4 solutions were alternately added to the wells, the plates were incubated to form the precursors, and this was followed by the addition of simulated body fluid (SBF) and a further incubation for 24h. These treatments resulted in the surfaces of the PS cell culture plates being completely covered with bone-like HAp. The coating of PS plates with HAp promoted the adhesion of mesenchymal stem cells (MSCs) and maintained cell growth that was as fast as that on tissue culture-treated PS (TCPS) plates. Osteogenic differentiation was greater, whereas adipogenic and chondrogenic differentiation was less in the culture on HAp-coated PS plates than in that on TCPS plates. The present method is useful for preparing HAp-coated PS plates at clean benches without the need for any expensive apparatus. HAp coated on PS plates by this method was a bone-like apatite with high bioactivity; therefore, the present HAp-coated PS plates are promising materials for assays of bone-related cells in the bone remodeling process.

  5. Mouse endometrial stromal cells produce basement-membrane components

    DEFF Research Database (Denmark)

    Wewer, U M; Damjanov, A; Weiss, J;

    1986-01-01

    During mouse pregnancy, uterine stromal cells transform into morphologically distinct decidual cells under the influence of the implanting embryo and a proper hormonal environment. Mechanical stimulation of hormonally primed uterine stromal cells leads to the same morphologic alterations. The dec...

  6. Requirements and testing methods for surfaces of metallic bipolar plates for low-temperature PEM fuel cells

    Science.gov (United States)

    Jendras, P.; Lötsch, K.; von Unwerth, T.

    2017-03-01

    To reduce emissions and to substitute combustion engines automotive manufacturers, legislature and first users aspire hydrogen fuel cell vehicles. Up to now the focus of research was set on ensuring functionality and increasing durability of fuel cell components. Therefore, expensive materials were used. Contemporary research and development try to substitute these substances by more cost-effective material combinations. The bipolar plate is a key component with the greatest influence on volume and mass of a fuel cell stack and they have to meet complex requirements. They support bending sensitive components of stack, spread reactants over active cell area and form the electrical contact to another cell. Furthermore, bipolar plates dissipate heat of reaction and separate one cell gastight from the other. Consequently, they need a low interfacial contact resistance (ICR) to the gas diffusion layer, high flexural strength, good thermal conductivity and a high durability. To reduce costs stainless steel is a favoured material for bipolar plates in automotive applications. Steel is characterized by good electrical and thermal conductivity but the acid environment requires a high chemical durability against corrosion as well. On the one hand formation of a passivating oxide layer increasing ICR should be inhibited. On the other hand pitting corrosion leading to increased permeation rate may not occur. Therefore, a suitable substrate lamination combination is wanted. In this study material testing methods for bipolar plates are considered.

  7. Iron-based alloy and nitridation treatment for PEM fuel cell bipolar plates

    Science.gov (United States)

    Brady, Michael P [Oak Ridge, TN; Yang, Bing [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN

    2010-11-09

    A corrosion resistant electrically conductive component that can be used as a bipolar plate in a PEM fuel cell application is composed of an alloy substrate which has 10-30 wt. % Cr, 0.5 to 7 wt. % V, and base metal being Fe, and a continuous surface layer of chromium nitride and vanadium nitride essentially free of base metal. A oxide layer of chromium vanadium oxide can be disposed between the alloy substrate and the continuous surface nitride layer. A method to prepare the corrosion resistant electrically conductive component involves a two-step nitridization sequence by exposing the alloy to a oxygen containing gas at an elevated temperature, and subsequently exposing the alloy to an oxygen free nitrogen containing gas at an elevated temperature to yield a component where a continuous chromium nitride layer free of iron has formed at the surface.

  8. Programmed Cell Death and Postharvest Deterioration of Horticultural Produce

    NARCIS (Netherlands)

    Woltering, E.J.; Iakimova, E.T.

    2010-01-01

    Programmed cell death (PCD) is a process where cells or tissues are broken down in an orderly and predictable manner, whereby nutrients are re-used by other cells, tissues or plant parts. The process of (petal) senescence shows many similarities to autophagic PCD in animal cells including a massive

  9. Efficient Differentiation of Mouse Embryonic Stem Cells into Insulin-Producing Cells

    Directory of Open Access Journals (Sweden)

    Szu-Hsiu Liu

    2012-01-01

    Full Text Available Embryonic stem (ES cells are a potential source of a variety of differentiated cells for cell therapy, drug discovery, and toxicology screening. Here, we present an efficacy strategy for the differentiation of mouse ES cells into insulin-producing cells (IPCs by a two-step differentiation protocol comprising of (i the formation of definitive endoderm in monolayer culture by activin A, and (ii this monolayer endoderm being induced to differentiate into IPCs by nicotinamide, insulin, and laminin. Differentiated cells can be obtained within approximately 7 days. The differentiation IPCs combined application of RT-PCR, ELISA, and immunofluorescence to characterize phenotypic and functional properties. In our study, we demonstrated that IPCs produced pancreatic transcription factors, endocrine progenitor marker, definitive endoderm, pancreatic β-cell markers, and Langerhans α and δ cells. The IPCs released insulin in a manner that was dose dependent upon the amount of glucose added. These techniques may be able to be applied to human ES cells, which would have very important ramifications for treating human disease.

  10. Fibroblastic reticular cells from lymph nodes attenuate T cell expansion by producing nitric oxide.

    Directory of Open Access Journals (Sweden)

    Stefanie Siegert

    Full Text Available Adaptive immune responses are initiated when T cells encounter antigen on dendritic cells (DC in T zones of secondary lymphoid organs. T zones contain a 3-dimensional scaffold of fibroblastic reticular cells (FRC but currently it is unclear how FRC influence T cell activation. Here we report that FRC lines and ex vivo FRC inhibit T cell proliferation but not differentiation. FRC share this feature with fibroblasts from non-lymphoid tissues as well as mesenchymal stromal cells. We identified FRC as strong source of nitric oxide (NO thereby directly dampening T cell expansion as well as reducing the T cell priming capacity of DC. The expression of inducible nitric oxide synthase (iNOS was up-regulated in a subset of FRC by both DC-signals as well as interferon-γ produced by primed CD8+ T cells. Importantly, iNOS expression was induced during viral infection in vivo in both LN FRC and DC. As a consequence, the primary T cell response was found to be exaggerated in Inos(-/- mice. Our findings highlight that in addition to their established positive roles in T cell responses FRC and DC cooperate in a negative feedback loop to attenuate T cell expansion during acute inflammation.

  11. Reversal of diabetes with insulin-producing cells derived in vitro from human pluripotent stem cells.

    Science.gov (United States)

    Rezania, Alireza; Bruin, Jennifer E; Arora, Payal; Rubin, Allison; Batushansky, Irina; Asadi, Ali; O'Dwyer, Shannon; Quiskamp, Nina; Mojibian, Majid; Albrecht, Tobias; Yang, Yu Hsuan Carol; Johnson, James D; Kieffer, Timothy J

    2014-11-01

    Transplantation of pancreatic progenitors or insulin-secreting cells derived from human embryonic stem cells (hESCs) has been proposed as a therapy for diabetes. We describe a seven-stage protocol that efficiently converts hESCs into insulin-producing cells. Stage (S) 7 cells expressed key markers of mature pancreatic beta cells, including MAFA, and displayed glucose-stimulated insulin secretion similar to that of human islets during static incubations in vitro. Additional characterization using single-cell imaging and dynamic glucose stimulation assays revealed similarities but also notable differences between S7 insulin-secreting cells and primary human beta cells. Nevertheless, S7 cells rapidly reversed diabetes in mice within 40 days, roughly four times faster than pancreatic progenitors. Therefore, although S7 cells are not fully equivalent to mature beta cells, their capacity for glucose-responsive insulin secretion and rapid reversal of diabetes in vivo makes them a promising alternative to pancreatic progenitor cells or cadaveric islets for the treatment of diabetes.

  12. Flow cytometric bacterial cell counts challenge conventional heterotrophic plate counts for routine microbiological drinking water monitoring.

    Science.gov (United States)

    Van Nevel, S; Koetzsch, S; Proctor, C R; Besmer, M D; Prest, E I; Vrouwenvelder, J S; Knezev, A; Boon, N; Hammes, F

    2017-04-15

    Drinking water utilities and researchers continue to rely on the century-old heterotrophic plate counts (HPC) method for routine assessment of general microbiological water quality. Bacterial cell counting with flow cytometry (FCM) is one of a number of alternative methods that challenge this status quo and provide an opportunity for improved water quality monitoring. After more than a decade of application in drinking water research, FCM methodology is optimised and established for routine application, supported by a considerable amount of data from multiple full-scale studies. Bacterial cell concentrations obtained by FCM enable quantification of the entire bacterial community instead of the minute fraction of cultivable bacteria detected with HPC (typically water samples per day, depending on the laboratory and selected staining procedure(s). Moreover, many studies have shown FCM total (TCC) and intact (ICC) cell concentrations to be reliable and robust process variables, responsive to changes in the bacterial abundance and relevant for characterising and monitoring drinking water treatment and distribution systems. The purpose of this critical review is to initiate a constructive discussion on whether FCM could replace HPC in routine water quality monitoring. We argue that FCM provides a faster, more descriptive and more representative quantification of bacterial abundance in drinking water.

  13. Generation of insulin-producing cells from gnotobiotic porcine skin-derived stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ji Hoon; Lee, Sung Ho; Heo, Young Tae [Department of Bioscience and Biotechnology, Bio-Organ Research Center, Konkuk University, Seoul 143-701 (Korea, Republic of); Uhm, Sang Jun [Department of Animal Biotechnology, Bio-Organ Research Center, Konkuk University, Seoul 143-701 (Korea, Republic of); Lee, Hoon Taek, E-mail: htl3675@konkuk.ac.kr [Department of Animal Biotechnology, Bio-Organ Research Center, Konkuk University, Seoul 143-701 (Korea, Republic of)

    2010-07-09

    A major problem in the treatment of type 1 diabetes mellitus is the limited availability of alternative sources of insulin-producing cells for islet transplantation. In this study, we investigated the effect of bone morphogenetic protein 4 (BMP-4) treatments of gnotobiotic porcine skin-derived stem cells (gSDSCs) on their reprogramming and subsequent differentiation into insulin-producing cells (IPCs). We isolated SDSCs from the ear skin of a gnotobiotic pig. During the proliferation period, the cells expressed stem-cell markers Oct-4, Sox-2, and CD90; nestin expression also increased significantly. The cells could differentiate into IPCs after treatments with activin-A, glucagon-like peptide-1 (GLP-1), and nicotinamide. After 15 days in the differentiation medium, controlled gSDSCs began expressing endocrine progenitor genes and proteins (Ngn3, Neuro-D, PDX-1, NKX2.2, NKX6.1, and insulin). The IPCs showed increased insulin synthesis after glucose stimulation. The results indicate that stem cells derived from the skin of gnotobiotic pigs can differentiate into IPCs under the appropriate conditions in vitro. Our three-stage induction protocol could be applied without genetic modification to source IPCs from stem cells in the skin of patients with diabetes for autologous transplantation.

  14. Human Liver Cells Expressing Albumin and Mesenchymal Characteristics Give Rise to Insulin-Producing Cells

    Directory of Open Access Journals (Sweden)

    Irit Meivar-Levy

    2011-01-01

    Full Text Available Activation of the pancreatic lineage in the liver has been suggested as a potential autologous cell replacement therapy for diabetic patients. Transcription factors-induced liver-to-pancreas reprogramming has been demonstrated in numerous species both in vivo and in vitro. However, human-derived liver cells capable of acquiring the alternate pancreatic repertoire have never been characterized. It is yet unknown whether hepatic-like stem cells or rather adult liver cells give rise to insulin-producing cells. Using an in vitro experimental system, we demonstrate that proliferating adherent human liver cells acquire mesenchymal-like characteristics and a considerable level of cellular plasticity. However, using a lineage-tracing approach, we demonstrate that insulin-producing cells are primarily generated in cells enriched for adult hepatic markers that coexpress both albumin and mesenchymal markers. Taken together, our data suggest that adult human hepatic tissue retains a substantial level of developmental plasticity, which could be exploited in regenerative medicine approaches.

  15. Highly efficient differentiation of human ES cells and iPS cells into mature pancreatic insulin-producing cells

    Institute of Scientific and Technical Information of China (English)

    Donghui Zhang; Wei Jiang; Meng Liu; Xin Sui; Xiaolei Yin; Song Chen; Yan Shi; Hongkui Deng

    2009-01-01

    Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells to differentiate into mature insulin-producing cells in a chemical-defined culture system. The differentiated human ES cells obtained by this approach comprised nearly 25% insulin-positive cells as assayed by flow cytometry analysis, which released insulin/C-peptide in response to glucose stimuli in a manner comparable to that of adult human islets. Most of these insulin-producing cells co-expressed mature β cell-specific markers such as NKX6-1 and PDX1, indicating a similar gene expression pattern to adult islet β cells in vivo. In this study, we also demonstrated that EGF facilitates the expansion of PDX1-positive pancreatic progenitors. Moreover, our protocol also succeeded in efficiently inducing human iPS cells to differentiate into insulin-producing cells. Therefore, this work not only provides a new model to study the mechanism of human pancreatic specialization and maturation in vitro, but also enhances the possibility of utilizing patient-specific iPS cells for the treatment of diabetes.

  16. Analysis of flow in a cone-and-plate apparatus with respect to spatial and temporal effects on endothelial cells.

    Science.gov (United States)

    Buschmann, M H; Dieterich, P; Adams, N A; Schnittler, H-J

    2005-03-01

    Endothelial cells, covering the inner surface of vessels and the heart, are permanently exposed to fluid flow, which affects the endothelial structure and the function. The response of endothelial cells to fluid shear stress is frequently investigated in cone-plate systems. For this type of device, we performed an analytical and numerical analysis of the steady, laminar, three-dimensional flow of a Newtonian fluid at low Reynolds numbers. Unsteady oscillating and pulsating flow was studied numerically by taking the geometry of a corresponding experimental setup into account. Our investigation provides detailed information with regard to shear-stress distribution at the plate as well as secondary flow. We show that: (i) there is a region on the plate where shear stress is almost constant and an analytical approach can be applied with high accuracy; (ii) detailed information about the flow in a real cone-plate device can only be obtained by numerical simulations; (iii) the pulsating flow is quasi-stationary; and (iv) there is a time lag on the order of 10(-3) s between cone rotation and shear stress generated on the plate.

  17. Standardization of the CFU-GM assay: Advantages of plating a fixed number of CD34+ cells in collagen gels.

    Science.gov (United States)

    Dobo, Irène; Pineau, Danielle; Robillard, Nelly; Geneviève, Frank; Piard, Nicole; Zandecki, Marc; Hermouet, Sylvie

    2003-10-01

    We investigated whether plating a stable amount of CD34(+) cells improves the CFU-GM assay. Data of CFU-GM assays performed with leukaphereses products in two transplant centers using a commercial collagen-based medium and unified CFU-GM scoring criteria were pooled and analyzed according to the numbers of CD34(+) cells plated. A first series of 113 CFU-GM assays was performed with a fixed number of mononuclear cells (i.e., a variable number of CD34(+) cells). In these cultures the CFU-GM/CD34 ratio varied according to the number of CD34(+) cells plated: median CFUGM/CD34 ratios were 1/6.2 to 1/6.6 for grafts containing or =2% CD34(+) cells. The median CFU-GM/CD34 ratio also varied depending on pathology: 1/9.3 for multiple myeloma (MM), 1/6.8 for Hodgkin's disease (HD), 1/6.5 for non-Hodgkin lymphoma (NHL), and 1/4.5 for solid tumors (ST). A second series of 95 CFU-GM assays was performed with a fixed number of CD34(+) cells (220/ml). The range of median CFU-GM/CD34 ratios was narrowed to 1/7.0 to 1/5.2, and coefficients of variation for CFU-GM counts decreased by half to 38.1% (NHL), 36.1% (MM), 49.9% (HD), and 22.4% (ST). In addition, CFU-GM scoring was facilitated as the percentages of cultures with >50 CFU/GM/ml decreased from 6.7% to 43.8% when a variable number of CD34(+) cells was plated, to 4.5% to 16.7% when 220 CD34(+) cells/ml were plated. Hence, plating a fixed number of CD34(+) cells in collagen gels improves the CFU-GM assay by eliminating cell number-related variability and reducing pathology-related variability in colony growth.

  18. Repeatability of differential goat bulk milk culture and associations with somatic cell count, total bacterial count, and standard plate count

    NARCIS (Netherlands)

    Koop, G.; Dik, N.; Nielen, M.; Lipman, L.J.A.

    2010-01-01

    The aims of this study were to assess how different bacterial groups in bulk milk are related to bulk milk somatic cell count (SCC), bulk milk total bacterial count (TBC), and bulk milk standard plate count (SPC) and to measure the repeatability of bulk milk culturing. On 53 Dutch dairy goat farms,

  19. Fetal Mesenchymal Stromal Cells Differentiating towards Chondrocytes Acquire a Gene Expression Profile Resembling Human Growth Plate Cartilage

    NARCIS (Netherlands)

    van Gool, S.A.; Emons, J.A.M.; Leijten, Jeroen Christianus Hermanus; Decker, E.; Sticht, C.; van Houwelingen, J.C.; Goeman, J.J.; Kleijburg, C.; Scherjon, S.; Gretz, N.; Wit, J.M.; Rappold, G.; Post, Janine Nicole; Karperien, Hermanus Bernardus Johannes

    2012-01-01

    Abstract We used human fetal bone marrow-derived mesenchymal stromal cells (hfMSCs) differentiating towards chondrocytes as an alternative model for the human growth plate (GP). Our aims were to study gene expression patterns associated with chondrogenic differentiation to assess whether

  20. [Establishment of Caco-2 cell monolayer model with collagen coating 6-well plates for study of traditional Chinese medicine prescription].

    Science.gov (United States)

    Yang, Yan-Fang; Wu, Ni; Yang, Xiu-Wei

    2014-02-01

    Caco-2 cell monolayer model is widely utilized in drug absorption study and 12-well transwellTM plates were commonly used to study the absorption of different kinds of natural products. To establish a stable method for the study of traditional Chinese medicine prescription, 6-well plates were chosen because of the larger well volumes than 12-well plates. To study the impacts of collagen kinds, coating density as well as coating time on the cell culture, the transepithelial electrical resistance of Caco-2 cell monolayers grown on different collagen coating transwells was determined, and the permeations of propranolol and atenolol as standard markers were detected with HPLC. The results showed that the kinds of collagen, the different coating densities and coating time of rat tail collagen had no significant influences on the Caco-2 cell monolayer integrality and absorption capacity. 6-well plates coated with 2 micro g Scm-2 rat tail collagen for 1 hour were enough reliable and suitable for the study of traditional Chinese medicine prescription in vitro.

  1. Comparison of bulk-tank standard plate count and somatic cell count for Wisconsin dairy farms in three size categories.

    Science.gov (United States)

    Ingham, S C; Hu, Y; Ané, C

    2011-08-01

    The objective of this study was to evaluate possible claims by advocates of small-scale dairy farming that milk from smaller Wisconsin farms is of higher quality than milk from larger Wisconsin farms. Reported bulk tank standard plate count (SPC) and somatic cell count (SCC) test results for Wisconsin dairy farms were obtained for February to December, 2008. Farms were sorted into 3 size categories using available size-tracking criteria: small (≤118 cows; 12,866 farms), large (119-713 cattle; 1,565 farms), and confined animal feeding operations (≥714 cattle; 160 farms). Group means were calculated (group=farm size category) for the farms' minimum, median, mean, 90th percentile, and maximum SPC and SCC. Statistical analysis showed that group means for median, mean, 90th percentile, and maximum SPC and SCC were almost always significantly higher for the small farm category than for the large farm and confined animal feeding operations farm categories. With SPC and SCC as quality criteria and the 3 farm size categories of ≤118, 119 to 713, and ≥714 cattle, the claim of Wisconsin smaller farms producing higher quality milk than Wisconsin larger farms cannot be supported.

  2. Imbalance between IL-17A-Producing Cells and Regulatory T Cells during Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Yuehua Hu

    2014-01-01

    Full Text Available Immune responses and inflammation are key elements in the pathogenesis of ischemic stroke (IS. Although the involvement of IL-17A in IS has been demonstrated using animal models, the involvement of IL-17A and IL-17-secreting T cell subsets in IS patients has not been verified, and whether the balance of Treg/IL-17-secreting T cells is altered in IS patients remains unknown. In the present study, we demonstrated that the proportion of peripheral Tregs and the levels of IL-10 and TGF-β were reduced in patients with IS compared with controls using flow cytometry (FCM, real-time PCR, and ELISA assays. However, the proportions of Th17 and γδ T cells, the primary IL-17A-secreting cells, increased dramatically, and these effects were accompanied by increases in the levels of IL-17A, IL-23, IL-6, and IL-1β in IS patients. These studies suggest that the increase in IL-17A-producing cells and decrease in Treg cells might contribute to the pathogenesis of IS. Manipulating the balance between Tregs and IL-17A-producing cells might be helpful for the treatment of IS.

  3. Multipotent stem cells isolated from the adult mouse retina are capable of producing functional photoreceptor cells.

    Science.gov (United States)

    Li, Tianqing; Lewallen, Michelle; Chen, Shuyi; Yu, Wei; Zhang, Nian; Xie, Ting

    2013-06-01

    Various stem cell types have been tested for their potential application in treating photoreceptor degenerative diseases, such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Only embryonic stem cells (ESCs) have so far been shown to generate functional photoreceptor cells restoring light response of photoreceptor-deficient mice, but there is still some concern of tumor formation. In this study, we have successfully cultured Nestin(+)Sox2(+)Pax6(+) multipotent retinal stem cells (RSCs) from the adult mouse retina, which are capable of producing functional photoreceptor cells that restore the light response of photoreceptor-deficient rd1 mutant mice following transplantation. After they have been expanded for over 35 passages in the presence of FGF and EGF, the cultured RSCs still maintain stable proliferation and differentiation potential. Under proper differentiation conditions, they can differentiate into all the major retinal cell types found in the adult retina. More importantly, they can efficiently differentiate into photoreceptor cells under optimized differentiation conditions. Following transplantation into the subretinal space of slowly degenerating rd7 mutant eyes, RSC-derived photoreceptor cells integrate into the retina, morphologically resembling endogenous photoreceptors and forming synapases with resident retinal neurons. When transplanted into eyes of photoreceptor-deficient rd1 mutant mice, a RP model, RSC-derived photoreceptors can partially restore light response, indicating that those RSC-derived photoreceptors are functional. Finally, there is no evidence for tumor formation in the photoreceptor-transplanted eyes. Therefore, this study has demonstrated that RSCs isolated from the adult retina have the potential of producing functional photoreceptor cells that can potentially restore lost vision caused by loss of photoreceptor cells in RP and AMD.

  4. Multipotent stem cells isolated from the adult mouse retina are capable of producing functional photoreceptor cells

    Institute of Scientific and Technical Information of China (English)

    Tianqing Li; Michelle Lewallen; Shuyi Chen; Wei Yu; Nian Zhang; Ting Xie

    2013-01-01

    Various stem cell types have been tested for their potential application in treating photoreceptor degenerative diseases,such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD).Only embryonic stem cells (ESCs) have so far been shown to generate functional photoreceptor cells restoring light response of photoreceptordeficient mice,but there is still some concern of tumor formation.In this study,we have successfully cultured Nestin+Sox2+Pax6+ multipotent retinal stem cells (RSCs) from the adult mouse retina,which are capable of producing functional photoreceptor cells that restore the light response of photoreceptor-deficient rd1 mutant mice following transplantation.After they have been expanded for over 35 passages in the presence of FGF and EGF,the cultured RSCs still maintain stable proliferation and differentiation potential.Under proper differentiation conditions,they can differentiate into all the major retinal cell types found in the adult retina.More importantly,they can efficiently differentiate into photoreceptor cells under optimized differentiation conditions.Following transplantation into the subretinal space of slowly degenerating rd7 mutant eyes,RSC-derived photoreceptor cells integrate into the retina,morphologically resembling endogenous photoreceptors and forming synapases with resident retinal neurons.When transplanted into eyes of photoreceptor-deficient rd1 mutant mice,a RP model,RSC-derived photoreceptors can partially restore light response,indicating that those RSC-derived photoreceptors are functional.Finally,there is no evidence for tumor formation in the photoreceptor-transplanted eyes.Therefore,this study has demonstrated that RSCs isolated from the adult retina have the potential of producing functional photoreceptor cells that can potentially restore lost vision caused by loss of photoreceptor cells in RP and AMD.

  5. Baculovirus Coinfection Strategy for Improved Galactosylation of Recombinant Glycoprotein Produced by Insect Cell Culture

    Science.gov (United States)

    Ney, Yap Wei; Rahman, Badarulhisam Abdul; Aziz, Azila Abdul

    Baculovirus Expression Vector System (BEVS) is widely used for the production of recombinant glycoproteins, but it is not ideal for pharmaceutical glycoprotein production due to incomplete glycosylation. The factors that ensure successful glycosylation are the presence of sufficient amount of glycosyltransferases, sugar nucleotides as the substrate donor and the recombinant protein as the substrate acceptor. In this study, we analyzed the galactosylation process by the introduction of ß-1,4galactosyltransferase (ß-1,4GalT) as the glycosyltransferase of interest and uridine-5`-diphosphogalactose (UDP-Gal) as the substrate donor. Recombinant human transferrin (rhTf) as a model protein was used as the substrate acceptor. Insect cell lines have been reported to produce a small amount of ß-1,4GalT and thus insufficient for effective galactosylation. In this study, we developed a method to produce galactosylated rhTf and optimized the expression of rhTf with better N-glycan quality. Recombinant ß-1,4GalT was introduced during protein expression by the coinfection of the BEVS with baculovirus carrying bovine ß-1,4GalT. To evaluate the extent of galactosylation by the coinfection strategy, a binding assay was established. In this binding assay, glycoprotein acceptor was absorbed onto ELISA plate surface. A lectin known as Ricinus communis agglutinin-I (RCA-I) labeled with peroxidase, was added and allowed to recognize Gal ß1>4GlcNAc group on the N-glycan of the glycoprotein, followed by appropriate color reaction measurements. Coexpression between rhTf and ß-1,4GalT did not show encouraging results due to the reduction of UDP-Gal upon baculovirus infection. This interesting finding suggested that the introduction of ß-1,4GalT alone was not sufficient for successful galactosylation. Alternatively, post harvest glycosylation method strategy seems to be a promising technique in the improvement of glycoprotein quality.

  6. Cytokine-producing T cell subsets in human leishmaniasis

    DEFF Research Database (Denmark)

    Kemp, Kåre

    2000-01-01

    Leishmania specific Th1/Th2 cells have been identified in humans as well as in mice. There is a correlation between the clinical outcome of the infection and the cytokine response profile. Generally, the production of Th2 cytokines leads to severe infection, whereas the production of Th1 cytokine...... cells mutually down-regulate each other. However, the presence of antigen specific regulatory T cell subsets may provide an environment that allows the presence of both Th1 and Th2 cells....

  7. Organotypic pancreatoids with native mesenchyme develop Insulin producing endocrine cells.

    Science.gov (United States)

    Scavuzzo, Marissa A; Yang, Diane; Borowiak, Malgorzata

    2017-09-07

    Replacement of lost beta cells in patients with diabetes has the potential to alleviate them of their disease, yet current protocols to make beta cells are inadequate for therapy. In vitro screens can reveal the signals necessary for endocrine maturation to improve beta cell production, however the complexities of in vivo development that lead to beta cell formation are lost in two-dimensional systems. Here, we create three-dimensional organotypic pancreatic cultures, named pancreatoids, composed of embryonic day 10.5 murine epithelial progenitors and native mesenchyme. These progenitors assemble in scaffold-free, floating conditions and, with the inclusion of native mesenchyme, develop into pancreatoids expressing markers of different pancreatic lineages including endocrine-like cells. Treatment of pancreatoids with (-)-Indolactam-V or phorbol 12-myristate 13-acetate, two protein kinase C activators, leads to altered morphology which otherwise would be overlooked in two-dimensional systems. Protein kinase C activation also led to fewer Insulin+ cells, decreased Ins1 and Ins2 mRNA levels, and increased Pdx1 and Hes1 mRNA levels with a high number of DBA+ cells. Thus, organotypic pancreatoids provide a useful tool for developmental studies, and can further be used for disease modeling, small molecules and genetic screens, or applied to human pluripotent stem cell differentiation for beta-like cell formation.

  8. Characterization of Thermal and Mechanical Properties of Polypropylene-Based Composites for Fuel Cell Bipolar Plates and Development of Educational Tools in Hydrogen and Fuel Cell Technologies

    Science.gov (United States)

    Lopez Gaxiola, Daniel

    2011-01-01

    In this project we developed conductive thermoplastic resins by adding varying amounts of three different carbon fillers: carbon black (CB), synthetic graphite (SG) and multi-walled carbon nanotubes (CNT) to a polypropylene matrix for application as fuel cell bipolar plates. This component of fuel cells provides mechanical support to the stack,…

  9. Characterization of Thermal and Mechanical Properties of Polypropylene-Based Composites for Fuel Cell Bipolar Plates and Development of Educational Tools in Hydrogen and Fuel Cell Technologies

    Science.gov (United States)

    Lopez Gaxiola, Daniel

    2011-01-01

    In this project we developed conductive thermoplastic resins by adding varying amounts of three different carbon fillers: carbon black (CB), synthetic graphite (SG) and multi-walled carbon nanotubes (CNT) to a polypropylene matrix for application as fuel cell bipolar plates. This component of fuel cells provides mechanical support to the stack,…

  10. Flow cytometric bacterial cell counts challenge conventional heterotrophic plate counts for routine microbiological drinking water monitoring

    KAUST Repository

    Van Nevel, S.

    2017-02-08

    Drinking water utilities and researchers continue to rely on the century-old heterotrophic plate counts (HPC) method for routine assessment of general microbiological water quality. Bacterial cell counting with flow cytometry (FCM) is one of a number of alternative methods that challenge this status quo and provide an opportunity for improved water quality monitoring. After more than a decade of application in drinking water research, FCM methodology is optimised and established for routine application, supported by a considerable amount of data from multiple full-scale studies. Bacterial cell concentrations obtained by FCM enable quantification of the entire bacterial community instead of the minute fraction of cultivable bacteria detected with HPC (typically < 1% of all bacteria). FCM measurements are reproducible with relative standard deviations below 3% and can be available within 15 min of samples arriving in the laboratory. High throughput sample processing and complete automation are feasible and FCM analysis is arguably less expensive than HPC when measuring more than 15 water samples per day, depending on the laboratory and selected staining procedure(s). Moreover, many studies have shown FCM total (TCC) and intact (ICC) cell concentrations to be reliable and robust process variables, responsive to changes in the bacterial abundance and relevant for characterising and monitoring drinking water treatment and distribution systems. The purpose of this critical review is to initiate a constructive discussion on whether FCM could replace HPC in routine water quality monitoring. We argue that FCM provides a faster, more descriptive and more representative quantification of bacterial abundance in drinking water.

  11. Operando lithium plating quantification and early detection of a commercial LiFePO4 cell cycled under dynamic driving schedule

    Science.gov (United States)

    Anseán, D.; Dubarry, M.; Devie, A.; Liaw, B. Y.; García, V. M.; Viera, J. C.; González, M.

    2017-07-01

    Lithium plating is considered one of the most detrimental phenomenon in lithium ion batteries (LIBs), as it increases cell degradation and might lead to safety issues. Plating induced LIB failure presents a major concern for emerging applications in transportation and electrical energy storage. Hence, the necessity to operando monitor, detect and analyze lithium plating becomes critical for safe and reliable usage of LIB systems. Here, we report in situ lithium plating analyses for a commercial graphite||LiFePO4 cell cycled under dynamic stress test (DST) driving schedule. We designed a framework based on incremental capacity (IC) analysis and mechanistic model simulations to quantify degradation modes, relate their effects to lithium plating occurrence and assess cell degradation. The results show that lithium plating was induced by large loss of active material on the negative electrode that eventually led the electrode to over-lithiate. Moreover, when lithium plating emerged, we quantified that the loss of lithium inventory pace was increased by a factor of four. This study illustrates the benefits of the proposed framework to improve lithium plating analysis. It also discloses the symptoms of lithium plating formation, which prove valuable for novel, online strategies on early lithium plating detection.

  12. Islet Brain 1 Protects Insulin Producing Cells against Lipotoxicity.

    Science.gov (United States)

    Brajkovic, Saška; Ferdaoussi, Mourad; Pawlowski, Valérie; Ezanno, Hélène; Plaisance, Valérie; Zmuda, Erik; Hai, Tsonwin; Annicotte, Jean-Sébastien; Waeber, Gérard; Abderrahmani, Amar

    2016-01-01

    Chronic intake of saturated free fatty acids is associated with diabetes and may contribute to the impairment of functional beta cell mass. Mitogen activated protein kinase 8 interacting protein 1 also called islet brain 1 (IB1) is a candidate gene for diabetes that is required for beta cell survival and glucose-induced insulin secretion (GSIS). In this study we investigated whether IB1 expression is required for preserving beta cell survival and function in response to palmitate. Chronic exposure of MIN6 and isolated rat islets cells to palmitate led to reduction of the IB1 mRNA and protein content. Diminution of IB1 mRNA and protein level relied on the inducible cAMP early repressor activity and proteasome-mediated degradation, respectively. Suppression of IB1 level mimicked the harmful effects of palmitate on the beta cell survival and GSIS. Conversely, ectopic expression of IB1 counteracted the deleterious effects of palmitate on the beta cell survival and insulin secretion. These findings highlight the importance in preserving the IB1 content for protecting beta cell against lipotoxicity in diabetes.

  13. Cloned calves produced by nuclear transfer from cultured cumulus cells

    Institute of Scientific and Technical Information of China (English)

    AN; Xiaorong(安晓荣); GOU; Kemian(苟克勉); ZHU; Shien(朱士恩); GUAN; Hong(关宏); HOU; Jian(侯健); LIN; Aixing(林爱星); ZENG; Shenming(曾申明); TIAN; Jianhui(田见辉); CHEN; Yongfu(陈永福)

    2002-01-01

    Short-term cultured cumulus cell lines (1-5BCC) derived from 5 individual cows were used in nuclear transfer (NT) and 1188 enucleated bovine oocytes matured in vitro were used as nuclear recipients. A total of 931 (78.4%) cloned embryos were reconstructed, of which 763 (82%) cleaved, 627 (67.3%) developed to 8-cell stage, and 275 (29.5%) reached blastocyst stage. The average cell number of blastocysts was 124±24.5 (n=20). In this study, the effects of donor cell sources, serum starvation of donor cells, time interval from fusion to activation (IFA) were also tested on cloning efficiency. These results showed that blastocyst rates of embryos reconstructed from 5 different individuals cells were significantly different among them (14.1%, 45.2%, 27.3%, 34.3%, vs 1.5%, P0.05); and that blastocyst rate (20.3%) of the group with fusion/activation interval of 2-3 h, was significantly lower than that of the 3-6 h groups (31.0%), while not significantly different among 3-4 h (P < 0.05), 4-5 h, and 5-6 h groups (P ≥ 0.05). Sixty-three thawed NT blastocysts were transferred to 31 recipient cows, of which 4 pregnancies were established and two cloned calves were given birth. These results indicate that serum starvation of cumulus cells is not a key factor for successful bovine cloning, while IFA treatment and sources of donor cells have effects on cloning efficiency.

  14. Producing fully ES cell-derived mice from eight-cell stage embryo injections.

    Science.gov (United States)

    DeChiara, Thomas M; Poueymirou, William T; Auerbach, Wojtek; Frendewey, David; Yancopoulos, George D; Valenzuela, David M

    2010-01-01

    In conventional methods for the generation of genetically modified mice, gene-targeted embryonic stem (ES) cells are injected into blastocyst-stage embryos or are aggregated with morula-stage embryos, which are then transferred to the uterus of a surrogate mother. F0 generation mice born from the embryos are chimeras composed of genetic contributions from both the modified ES cells and the recipient embryos. Obtaining a mouse strain that carries the gene-targeted mutation requires breeding the chimeras to transmit the ES cell genetic component through the germ line to the next (F1) generation (germ line transmission, GLT). To skip the chimera stage, we developed the VelociMouse method, in which injection of genetically modified ES cells into eight-cell embryos followed by maturation to the blastocyst stage and transfer to a surrogate mother produces F0 generation mice that are fully derived from the injected ES cells and exhibit a 100% GLT efficiency. The method is simple and flexible. Both male and female ES cells can be introduced into the eight-cell embryo by any method of injection or aggregation and using all ES cell and host embryo combinations from inbred, hybrid, and outbred genetic backgrounds. The VelociMouse method provides several unique opportunities for shortening project timelines and reducing mouse husbandry costs. First, as VelociMice exhibit 100% GLT, there is no need to test cross chimeras to establish GLT. Second, because the VelociMouse method permits efficient production of ES cell-derived mice from female ES cells, XO ES cell subclones, identified by screening for spontaneous loss of the Y chromosome, can be used to generate F0 females that can be bred with isogenic F0 males derived from the original targeted ES cell clone to obtain homozygous mutant mice in the F1 generation. Third, as VelociMice are genetically identical to the ES cells from which they were derived, the VelociMouse method opens up myriad possibilities for creating mice with

  15. PDX1-engineered embryonic stem cell-derived insulin producing cells regulate hyperglycemia in diabetic mice

    Directory of Open Access Journals (Sweden)

    Raikwar Sudhanshu P

    2012-10-01

    Full Text Available Abstract Background Type 1 diabetes can be treated by the transplantation of cadaveric whole pancreata or isolated pancreatic islets. However, this form of treatment is hampered by the chronic shortage of cadaveric donors. Embryonic stem (ES cell-derived insulin producing cells (IPCs offer a potentially novel source of unlimited cells for transplantation to treat type 1 and possibly type 2 diabetes. However, thus far, the lack of a reliable protocol for efficient differentiation of ES cells into IPCs has hindered the clinical exploitation of these cells. Methods To efficiently generate IPCs using ES cells, we have developed a double transgenic ES cell line R1Pdx1AcGFP/RIP-Luc that constitutively expresses pancreatic β-cell-specific transcription factor pancreatic and duodenal homeobox gene 1 (Pdx1 as well as rat insulin promoter (RIP driven luciferase reporter. We have established several protocols for the reproducible differentiation of ES cells into IPCs. The differentiation of ES cells into IPCs was monitored by immunostaining as well as real-time quantitative RT-PCR for pancreatic β-cell-specific markers. Pancreatic β-cell specific RIP became transcriptionally active following the differentiation of ES cells into IPCs and induced the expression of the luciferase reporter. Glucose stimulated insulin secretion by the ES cell-derived IPCs was measured by ELISA. Further, we have investigated the therapeutic efficacy of ES cell-derived IPCs to correct hyperglycemia in syngeneic streptozotocin (STZ-treated diabetic mice. The long term fate of the transplanted IPCs co-expressing luciferase in syngeneic STZ-induced diabetic mice was monitored by real time noninvasive in vivo bioluminescence imaging (BLI. Results We have recently demonstrated that spontaneous in vivo differentiation of R1Pdx1AcGFP/RIP-Luc ES cell-derived pancreatic endoderm-like cells (PELCs into IPCs corrects hyperglycemia in diabetic mice. Here, we investigated whether R1Pdx1Ac

  16. The Hagfish Gland Thread Cell: A Fiber-Producing Cell Involved in Predator Defense

    Directory of Open Access Journals (Sweden)

    Douglas S. Fudge

    2016-05-01

    Full Text Available Fibers are ubiquitous in biology, and include tensile materials produced by specialized glands (such as silks, extracellular fibrils that reinforce exoskeletons and connective tissues (such as chitin and collagen, as well as intracellular filaments that make up the metazoan cytoskeleton (such as F-actin, microtubules, and intermediate filaments. Hagfish gland thread cells are unique in that they produce a high aspect ratio fiber from cytoskeletal building blocks within the confines of their cytoplasm. These threads are elaborately coiled into structures that readily unravel when they are ejected into seawater from the slime glands. In this review we summarize what is currently known about the structure and function of gland thread cells and we speculate about the mechanism that these cells use to produce a mechanically robust fiber that is almost one hundred thousand times longer than it is wide. We propose that a key feature of this mechanism involves the unidirectional rotation of the cell’s nucleus, which would serve to twist disorganized filaments into a coherent thread and impart a torsional stress on the thread that would both facilitate coiling and drive energetic unravelling in seawater.

  17. Continuous electricity generation from domestic wastewater and organic substrates in a flat plate microbial fuel cell.

    Science.gov (United States)

    Min, Booki; Logan, Bruce E

    2004-11-01

    A microbial fuel cell (MFC) is a device that converts organic matter to electricity using microorganisms as the biocatalyst. Most MFCs contain two electrodes separated into one or two chambers that are operated as a completely mixed reactor. In this study, a flat plate MFC (FPMFC) was designed to operate as a plug flow reactor (no mixing) using a combined electrode/proton exchange membrane (PEM) system. The reactor consisted of a single channel formed between two nonconductive plates that were separated into two halves by the electrode/PEM assembly. Each electrode was placed on an opposite side of the PEM, with the anode facing the chamber containing the liquid phase and the cathode facing a chamber containing only air. Electricity generation using the FPMFC was examined by continuously feeding a solution containing wastewater, or a specific substrate, into the anode chamber. The system was initially acclimated for 1 month using domestic wastewater orwastewater enriched with a specific substrate such as acetate. Average power density using only domestic wastewater was 72+/-1 mW/m2 at a liquid flow rate of 0.39 mL/min [42% COD (chemical oxygen demand) removal, 1.1 h HRT (hydraulic retention time)]. At a longer HRT = 4.0 h, there was 79% COD removal and an average power density of 43+/-1 mW/m2. Power output was found to be a function of wastewater strength according to a Monod-type relationship, with a half-saturation constant of Ks = 461 or 719 mg COD/L. Power generation was sustained at high rates with several organic substrates (all at approximately 1000 mg COD/L), including glucose (212+/-2 mW/ m2), acetate (286+/-3 mW/m2), butyrate (220+/-1 mW/ m2), dextran (150+/-1 mW/m2), and starch (242+/-3 mW/ m2). These results demonstrate the versatility of power generation in a MFC with a variety of organic substrates and show that power can be generated at a high rate in a continuous flow reactor system.

  18. Visibly transparent polymer solar cells produced by solution processing.

    Science.gov (United States)

    Chen, Chun-Chao; Dou, Letian; Zhu, Rui; Chung, Choong-Heui; Song, Tze-Bin; Zheng, Yue Bing; Hawks, Steve; Li, Gang; Weiss, Paul S; Yang, Yang

    2012-08-28

    Visibly transparent photovoltaic devices can open photovoltaic applications in many areas, such as building-integrated photovoltaics or integrated photovoltaic chargers for portable electronics. We demonstrate high-performance, visibly transparent polymer solar cells fabricated via solution processing. The photoactive layer of these visibly transparent polymer solar cells harvests solar energy from the near-infrared region while being less sensitive to visible photons. The top transparent electrode employs a highly transparent silver nanowire-metal oxide composite conducting film, which is coated through mild solution processes. With this combination, we have achieved 4% power-conversion efficiency for solution-processed and visibly transparent polymer solar cells. The optimized devices have a maximum transparency of 66% at 550 nm.

  19. Differentiation, distribution and gammadelta T cell-driven regulation of IL-22-producing T cells in tuberculosis.

    Directory of Open Access Journals (Sweden)

    Shuyu Yao

    2010-02-01

    Full Text Available Differentiation, distribution and immune regulation of human IL-22-producing T cells in infections remain unknown. Here, we demonstrated in a nonhuman primate model that M. tuberculosis infection resulted in apparent increases in numbers of T cells capable of producing IL-22 de novo without in vitro Ag stimulation, and drove distribution of these cells more dramatically in lungs than in blood and lymphoid tissues. Consistently, IL-22-producing T cells were visualized in situ in lung tuberculosis (TB granulomas by confocal microscopy and immunohistochemistry, indicating that mature IL-22-producing T cells were present in TB granuloma. Surprisingly, phosphoantigen HMBPP activation of Vgamma2Vdelta2 T cells down-regulated the capability of T cells to produce IL-22 de novo in lymphocytes from blood, lung/BAL fluid, spleen and lymph node. Up-regulation of IFNgamma-producing Vgamma2Vdelta2 T effector cells after HMBPP stimulation coincided with the down-regulated capacity of these T cells to produce IL-22 de novo. Importantly, anti-IFNgamma neutralizing Ab treatment reversed the HMBPP-mediated down-regulation effect on IL-22-producing T cells, suggesting that Vgamma2Vdelta2 T-cell-driven IFNgamma-networking function was the mechanism underlying the HMBPP-mediated down-regulation of the capability of T cells to produce IL-22. These novel findings raise the possibility to ultimately investigate the function of IL-22 producing T cells and to target Vgamma2Vdelta2 T cells for balancing potentially hyper-activating IL-22-producing T cells in severe TB.

  20. Integrating Wind And Solar With Hydrogen Producing Fuel Cells

    NARCIS (Netherlands)

    Hemmes, K.

    2007-01-01

    The often proposed solution for the fluctuating wind energy supply is the conversion of the surplus of wind energy into hydrogen by means of electrolysis. In this paper a patented alternative is proposed consisting of the integration of wind turbines with internal reforming fuel-cells, capable of

  1. Integrating Wind And Solar With Hydrogen Producing Fuel Cells

    NARCIS (Netherlands)

    Hemmes, K.

    2007-01-01

    The often proposed solution for the fluctuating wind energy supply is the conversion of the surplus of wind energy into hydrogen by means of electrolysis. In this paper a patented alternative is proposed consisting of the integration of wind turbines with internal reforming fuel-cells, capable of co

  2. Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate

    Science.gov (United States)

    Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min

    2016-04-01

    Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion.

  3. Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate.

    Science.gov (United States)

    Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min

    2016-01-01

    Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion.

  4. Gene probes to detect cross-culture contamination in hormone producing cell lines

    DEFF Research Database (Denmark)

    Matsuba, I; Lernmark, A; Madsen, Ole Dragsbæk

    1988-01-01

    Cross-culture contamination of cell lines propagated in continuous culture is a frequent event and particularly difficult to resolve in cells expressing similar phenotypes. We demonstrate that DNA-DNA hybridization to blotted endonuclease-digested cell DNA effectively detects cross-culture...... the effective use of gene probes to control the origin of cell cultures....... contamination to monitor inter-species as well as intra-species cross contamination. An insulin-producing cell-line, Clone-16, originally cloned from a human fetal endocrine pancreatic cell line did not produce human c-peptide as anticipated. DNA from these cells showed no hybridization to the human ALU...

  5. IL-9-Producing Mast Cell Precursors and Food Allergy

    Science.gov (United States)

    2016-10-01

    Faculty of Allied Health Sciences, Thammasat University, Bangkok; cthe Department of Immunology, University of Texas and MD Anderson Cancer Center...www.healthline.com/ health -news/scientists-discover-new-cell- that-may-be-key-to-food-allergies-092215 (2) Peer-Reviewed Scientific Journals: (i) Chen...Peyer’s patch (PP), mesenteric lymph nodes (MLNs), spleen, lung, or liver (Figure 1I). Together, these results suggest an association of Lin IL-9

  6. Progress in amorphous silicon solar cells produced by reactive sputtering

    Science.gov (United States)

    Moustakas, T. D.

    The photovoltaic properties of reactively sputtered amorphous silicon are reviewed and it is shown that efficient PIN solar cells can be fabricated by the method of sputtering. The photovoltaic properties of the intrinsic films correlate with their structural and compositional inhomogeneities. Hydrogen incorporation and small levels of phosphorus and boron impurities also affect the photovoltaic properties through reduction of residual dangling bond related defects and modification of their occupation. The optical and transport properties of the doped P and N-films were found to depend sensitively on the amount of hydrogen and boron or phosphorus incorporation into the films as well as on their degree of crystallinity. Combination of the best intrinsic and doped films leads to PIN solar cell structures generating J(sc) of 13 mA/sq cm and V(oc) of between 0.85 to 0.95 volts. The efficiency of these devices, 5 to 6 percent, is limited by the low FF, typically about 50 percent. As a further test to the potential of this technology efficient tandem solar cell structures were fabricated, and device design concepts, such as the incorporation of optically reflective back contacts were tested.

  7. A Novel Heat Pipe Plate for Passive Thermal Control of Fuel Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project aims to develop a lightweight, highly thermally and electrically conductive heat pipe plate for passive removal of the heat from the individual...

  8. Repeatability of differential goat bulk milk culture and associations with somatic cell count, total bacterial count, and standard plate count

    OpenAIRE

    Koop, G.; Dik, N; Nielen, M; Lipman, L. J. A.

    2010-01-01

    The aims of this study were to assess how different bacterial groups in bulk milk are related to bulk milk somatic cell count (SCC), bulk milk total bacterial count (TBC), and bulk milk standard plate count (SPC) and to measure the repeatability of bulk milk culturing. On 53 Dutch dairy goat farms, 3 bulk milk samples were collected at intervals of 2 wk. The samples were cultured for SPC, coliform count, and staphylococcal count and for the presence of Staphylococcus aureus. Furthermore, SCC ...

  9. Application of dielectric spectroscopy for monitoring high cell density in monoclonal antibody producing CHO cell cultivations.

    Science.gov (United States)

    Párta, László; Zalai, Dénes; Borbély, Sándor; Putics, Akos

    2014-02-01

    The application of dielectric spectroscopy was frequently investigated as an on-line cell culture monitoring tool; however, it still requires supportive data and experience in order to become a robust technique. In this study, dielectric spectroscopy was used to predict viable cell density (VCD) at industrially relevant high levels in concentrated fed-batch culture of Chinese hamster ovary cells producing a monoclonal antibody for pharmaceutical purposes. For on-line dielectric spectroscopy measurements, capacitance was scanned within a wide range of frequency values (100-19,490 kHz) in six parallel cell cultivation batches. Prior to detailed mathematical analysis of the collected data, principal component analysis (PCA) was applied to compare dielectric behavior of the cultivations. PCA analysis resulted in detecting measurement disturbances. By using the measured spectroscopic data, partial least squares regression (PLS), Cole-Cole, and linear modeling were applied and compared in order to predict VCD. The Cole-Cole and the PLS model provided reliable prediction over the entire cultivation including both the early and decline phases of cell growth, while the linear model failed to estimate VCD in the later, declining cultivation phase. In regards to the measurement error sensitivity, remarkable differences were shown among PLS, Cole-Cole, and linear modeling. VCD prediction accuracy could be improved in the runs with measurement disturbances by first derivative pre-treatment in PLS and by parameter optimization of the Cole-Cole modeling.

  10. Evaluation of CoBlast Coated Titanium Alloy as Proton Exchange Membrane Fuel Cell Bipolar Plates

    Directory of Open Access Journals (Sweden)

    Atinuke M. Oladoye

    2014-01-01

    Full Text Available We investigated the potential of graphite based coatings deposited on titanium V alloy by a low-cost powder based process for bipolar plate application. The coatings which were deposited from a mixture of graphite and alumina powders at ambient temperature, pressure of 90 psi, and speed of 20 mm were characterised and electrochemically polarised in 0.5 M H2SO4 + 2 ppm HF bubbled with air and hydrogen gas to depict the cathode and anode PEM fuel cell environment, respectively. Surface conductivity and water contact angles were also evaluated. Corrosion current in the 1 μA/cm2 range in both cathodic and anodic environment at room temperature and showed negligible influence on the electrochemical behaviour of the bare alloy. Similar performance, which was attributed to the discontinuities in the coatings, was also observed when polarised at 0.6 V and −0.1 V with air and hydrogen bubbling at 70∘C respectively. At 140 N/cm2, the coated alloy exhibited contact resistance of 45.70 mΩ·cm2 which was lower than that of the bare alloy (66.50 mΩ·cm2 but twice that of graphite (21.29 mΩ·cm2. Similarly, the wettability test indicated that the coated layer exhibited higher contact angle of 99.63° than that of the bare alloy (66.32°. Over all, these results indicated need for improvement in the coating process to achieve a continuous layer.

  11. Comparison between beryllium and diamond-backing plates in diamond-anvil cells: Application to single-crystal X-ray diffraction high-pressure data

    DEFF Research Database (Denmark)

    Periotto, Benedetta; Nestola, Fabrizio; Balic Zunic, Tonci;

    2011-01-01

    A direct comparison between two complete intensity datasets, collected on the same sample loaded in two identical diamond-anvil pressure cells equipped, respectively, with beryllium and diamond backing plates was performed. The results clearly demonstrate that the use of diamond-backing plates...

  12. Preparation and properties of functionalized multiwalled carbon nanotubes/polypropylene nanocomposite bipolar plates for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Liao, Shu-Hang; Weng, Cheng-Chih; Yen, Chuan-Yu; Hsiao, Min-Chien; Ma, Chen-Chi M.; Tsai, Ming-Chi; Su, Ay; Yen, Ming-Yu; Lin, Yu-Feng; Liu, Po-Lan

    Multiwalled carbon nanotubes (MWCNTs) are covalently modified with different molecular weights 400 and 2000 poly(oxyalkylene)-amine bearing the diglycidyl ether of bisphenol A (DGEBA) epoxy (POA400-DGEBA and POA2000-DGEBA) oligomers. The oxidized MWCNTs (MWCNTs-COOH) are converted to the acid chloride-functionalized MWCNTs, followed by the reaction with POA-DGEBAs to prepare the MWCNTs/POA400-DGEBA and MWCNTs/POA2000-DGEBA. FTIR, thermogravimetric analysis (TGA) and high resolution X-ray photoelectron spectra (XPS) reveal that the POA-DGEBAs are covalently attached to the surface of MWCNTs. The morphology of MWCNTs/POA-DGEBA is observed by TEM. The POA400-DGEBA coated on the MWCNTs is thicker and more uniform. However, the coating of POA2000-DGEBA on the MWCNTs shows a worm-like bulk substance and the MWCNT surface is bare. In addition, the flexural strength and the bulk electrical conductivity of the MWCNTs/polypropylene nanocomposite bipolar plates are measured 59% and 505% higher than those of the original composite bipolar plates by adding 8 phr of MWCNTs/POA400-DGEBA. The maximum current density and power density of the single cell test for the nanocomposite bipolar plate with 4 phr MWCNTs/POA400-DGEBA are 1.32 A cm -2 and 0.533 W cm -2, respectively. The overall performance confirms the functionalized MWCNTs/polypropylene nanocomposite bipolar plates prepared in this study are suitable for PEMFC application.

  13. Preparation and properties of functionalized multiwalled carbon nanotubes/polypropylene nanocomposite bipolar plates for polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Shu-Hang; Weng, Cheng-Chih; Yen, Chuan-Yu.; Hsiao, Min-Chien; Ma, Chen-Chi M.; Yen, Ming-Yu.; Liu, Po-Lan [Department of Chemical Engineering, National Tsing Hua University, Hsin-Chu 30043 (China); Tsai, Ming-Chi [Department of Engineering and System Science, National Tsing Hua University, Hsin-Chu 30043 (China); Su, Ay [Fuel Cell Center, Yuan Ze University, Tao-Yuan 32003 (China); Lin, Yu-Feng [Plastics Industry Development Center, Tai-Chung 40768 (China)

    2010-01-01

    Multiwalled carbon nanotubes (MWCNTs) are covalently modified with different molecular weights 400 and 2000 poly(oxyalkylene)-amine bearing the diglycidyl ether of bisphenol A (DGEBA) epoxy (POA400-DGEBA and POA2000-DGEBA) oligomers. The oxidized MWCNTs (MWCNTs-COOH) are converted to the acid chloride-functionalized MWCNTs, followed by the reaction with POA-DGEBAs to prepare the MWCNTs/POA400-DGEBA and MWCNTs/POA2000-DGEBA. FTIR, thermogravimetric analysis (TGA) and high resolution X-ray photoelectron spectra (XPS) reveal that the POA-DGEBAs are covalently attached to the surface of MWCNTs. The morphology of MWCNTs/POA-DGEBA is observed by TEM. The POA400-DGEBA coated on the MWCNTs is thicker and more uniform. However, the coating of POA2000-DGEBA on the MWCNTs shows a worm-like bulk substance and the MWCNT surface is bare. In addition, the flexural strength and the bulk electrical conductivity of the MWCNTs/polypropylene nanocomposite bipolar plates are measured 59% and 505% higher than those of the original composite bipolar plates by adding 8 phr of MWCNTs/POA400-DGEBA. The maximum current density and power density of the single cell test for the nanocomposite bipolar plate with 4 phr MWCNTs/POA400-DGEBA are 1.32 A cm{sup -2} and 0.533 W cm{sup -2}, respectively. The overall performance confirms the functionalized MWCNTs/polypropylene nanocomposite bipolar plates prepared in this study are suitable for PEMFC application. (author)

  14. The Notch-target gene hairy2a impedes the involution of notochordal cells by promoting floor plate fates in Xenopus embryos.

    Science.gov (United States)

    López, Silvia L; Rosato-Siri, María V; Franco, Paula G; Paganelli, Alejandra R; Carrasco, Andrés E

    2005-03-01

    We have previously shown that the early Xenopus organiser contains cells equally potent to give rise to notochord or floor plate, and that Notch signalling triggers a binary decision, favouring the floor plate fate at the expense of the notochord. Now, we present evidence that Delta1 is the ligand that triggers the binary switch, which is executed through the Notch-mediated activation of hairy2a in the surrounding cells within the organiser, impeding their involution through the blastopore and promoting their incorporation into the hairy2a+ notoplate precursors (future floor-plate cells) in the dorsal non-involuting marginal zone.

  15. Electrochemically Produced Graphene for Microporous Layers in Fuel Cells.

    Science.gov (United States)

    Najafabadi, Amin Taheri; Leeuwner, Magrieta J; Wilkinson, David P; Gyenge, Előd L

    2016-07-01

    The microporous layer (MPL) is a key cathodic component in proton exchange membrane fuel cells owing to its beneficial influence on two-phase mass transfer. However, its performance is highly dependent on material properties such as morphology, porous structure, and electrical resistance. To improve water management and performance, electrochemically exfoliated graphene (EGN) microsheets are considered as an alternative to the conventional carbon black (CB) MPLs. The EGN-based MPLs decrease the kinetic overpotential and the Ohmic potential loss, whereas the addition of CB to form a composite EGN+CB MPL improves the mass-transport limiting current density drastically. This is reflected by increases of approximately 30 and 70 % in peak power densities at 100 % relative humidity (RH) compared with those for CB- and EGN-only MPLs, respectively. The composite EGN+CB MPL also retains the superior performance at a cathode RH of 20 %, whereas the CB MPL shows significant performance loss.

  16. In vitro and in vivo evaluation of insulin-producing beta TC6-F7 cells in microcapsules.

    Science.gov (United States)

    Zhou, D; Sun, A M; Li, X; Mamujee, S N; Vacek, I; Georgiou, J; Wheeler, M B

    1998-05-01

    In the present study, the insulin secretory capacity of beta TC6-F7 cells in microcapsules was evaluated. The cell mass within capsules was found to expand in a three-dimensional fashion, in contrast to cells seeded on plates that grew as a monolayer. In in vitro studies, both free and encapsulated cells were found to secrete insulin in the absence of glucose, at 13.6 +/- 1.1 and 14.5 +/- 0.9 ng.10(6) cells-1.60 min-1, respectively, with the response rising to a maximum of 26.0 +/- 0.8 and 31 +/- 2.3 ng.10(6) cells-1.60 min-1 in the presence of 16.8 mM glucose. Encapsulated cells were able to produce Ca2+ responses in the presence of KCl (50 mM) and BAY K 8644 (100 microM). In in vivo studies, intraperitoneal transplantation of 3.0 x 10(6) microencapsulated cells into mice (n = 5) with streptozotocin-induced diabetes resulted in the restoration of normoglycemia up to 57 days. Insulin concentrations rose from 0.4 +/- 0.1 ng/ml before the graft administration to 2.2 +/- 0.8 ng/ml after the transplantation in the normoglycemic recipients. An oral glucose challenge in transplant recipients demonstrated a flat glucose response, suggesting extremely high glucose clearance rates. These data demonstrate the potential use of the immunoisolated beta-cell lines for the treatment of diabetes.

  17. Rapid depletion of dissolved oxygen in 96-well microtiter plate Staphylococcus epidermidis biofilm assays promotes biofilm development and is influenced by inoculum cell concentration.

    Science.gov (United States)

    Cotter, John J; O'Gara, James P; Casey, Eoin

    2009-08-01

    Biofilm-related research using 96-well microtiter plates involves static incubation of plates indiscriminate of environmental conditions, making oxygen availability an important variable which has not been considered to date. By directly measuring dissolved oxygen concentration over time we report here that dissolved oxygen is rapidly consumed in Staphylococcus epidermidis biofilm cultures grown in 96-well plates irrespective of the oxygen concentration in the gaseous environment in which the plates are incubated. These data indicate that depletion of dissolved oxygen during growth of bacterial biofilm cultures in 96-well plates may significantly influence biofilm production. Furthermore higher inoculum cell concentrations are associated with more rapid consumption of dissolved oxygen and higher levels of S. epidermidis biofilm production. Our data reveal that oxygen depletion during bacterial growth in 96-well plates may significantly influence biofilm production and should be considered in the interpretation of experimental data using this biofilm model.

  18. From Human Mesenchymal Stem Cells to Insulin-Producing Cells: Comparison between Bone Marrow- and Adipose Tissue-Derived Cells

    Directory of Open Access Journals (Sweden)

    Mahmoud M. Gabr

    2017-01-01

    Full Text Available The aim of this study is to compare human bone marrow-derived mesenchymal stem cells (BM-MSCs and adipose tissue-derived mesenchymal stem cells (AT-MSCs, for their differentiation potentials to form insulin-producing cells. BM-MSCs were obtained during elective orthotopic surgery and AT-MSCs from fatty aspirates during elective cosmetics procedures. Following their expansion, cells were characterized by phenotyping, trilineage differentiation ability, and basal gene expression of pluripotency genes and for their metabolic characteristics. Cells were differentiated according to a Trichostatin-A based protocol. The differentiated cells were evaluated by immunocytochemistry staining for insulin and c-peptide. In addition the expression of relevant pancreatic endocrine genes was determined. The release of insulin and c-peptide in response to a glucose challenge was also quantitated. There were some differences in basal gene expression and metabolic characteristics. After differentiation the proportion of the resulting insulin-producing cells (IPCs, was comparable among both cell sources. Again, there were no differences neither in the levels of gene expression nor in the amounts of insulin and c-peptide release as a function of glucose challenge. The properties, availability, and abundance of AT-MSCs render them well-suited for applications in regenerative medicine. Conclusion. BM-MSCs and AT-MSCs are comparable regarding their differential potential to form IPCs. The availability and properties of AT-MSCs render them well-suited for applications in regenerative medicine.

  19. Arabidopsis Kinesins HINKEL and TETRASPORE Act Redundantly to Control Cell Plate Expansion during Cytokinesis in the Male Garnetophyte

    Institute of Scientific and Technical Information of China (English)

    Sung-Aeong Oh; Valérie Bourdon; Madhumita Das'Pal; Hugh Dickinson; David Twell

    2008-01-01

    Asymmetric cell division at pollen mitosis I(PMI)is required to specify the differentiaI fate of the daughter vegetative and generative cells.Cytokinesis at PMI displays specialized features,and it has been suggested that there might be distinct molecular pathways underpinning different modes of cytokinesis in plants.Activation of the NACKPQR MAP kinase signaling pathway,which is essentiaI for somatic cell cytokinesis in tobacco,depends upon the NACK1and NACK2 kinesin-related proteins.Their Arabidopsis orthologs.HINKEL(HIK)and TETRAsPORE(TES).were reported to be essential for cytokinesis in somatic cells and in microsporoctes.respectively.More recently,HIK and TES were shown to have a functionally redundant role in female gametophytic cvtokinesis.We report here that HIK and TES are co-expressed in microspores and developing pollen,and,through analysis of microspore and pollen development in double heterozygote mutants.the occurrence of cell plate expansion defects during cytokinesis at PMI.The data demonstrate a functionally redundant role for HIK and TES in cell plate expansion during male gametophytic cytokinesis.extending the concept that different modes of cytokinesis are executed by a common signaling pathway,but reinforcing the individuality of gametophytic cytokinesis in its requirement for either TES or HIK.

  20. Polarized Th2 like cells, in the absence of Th0 cells, are responsible for lymphocyte produced IL-4 in high IgE-producer schistosomiasis patients

    Directory of Open Access Journals (Sweden)

    Soares-Silveira Alda

    2002-07-01

    Full Text Available Abstract Background Human resistance to re-infection with S. mansoni is correlated with high levels of anti-soluble adult worm antigens (SWAP IgE. Although it has been shown that IL-4 and IL-5 are crucial in establishing IgE responses in vitro, the active in vivo production of these cytokines by T cells, and the degree of polarization of Th2 vs. Th0 in human schistosomiasis is not known. To address this question, we determined the frequency of IL-4 and IFN-γ or IL-5 and IL-2 producing lymphocytes from schistosomiasis patients with high or low levels of IgE anti-SWAP. Results Our analysis showed that high and low IgE-producers responded equally to schistosomiasis antigens as determined by proliferation. Moreover, patients from both groups displayed similar percentages of circulating lymphocytes. However, high IgE-producers had an increased percentage of activated CD4+ T cells as compared to the low IgE-producers. Moreover, intracellular cytokine analysis, after short-term stimulation with anti-CD3/CD28 mAbs, showed that IgE high-producers display an increase in the percentage of T lymphocytes expressing IL-4 and IL-5 as compared to IgE low-responders. A coordinate control of the frequency of IL-4 and IL-5 producing lymphocytes in IgE high, but not IgE low-responders, was observed. Conclusions High IgE phenotype human schistosomiasis patients exhibit a coordinate regulation of IL-4 and IL-5 producing cells and the lymphocyte derived IL-4 comes from true polarized Th2 like cells, in the absence of measurable Th0 cells as measured by co-production of IL-4 and IFN-γ.

  1. Generalized Fibonacci zone plates

    CERN Document Server

    Ke, Jie; Zhu, Jianqiang

    2015-01-01

    We propose a family of zone plates which are produced by the generalized Fibonacci sequences and their axial focusing properties are analyzed in detail. Compared with traditional Fresnel zone plates, the generalized Fibonacci zone plates present two axial foci with equal intensity. Besides, we propose an approach to adjust the axial locations of the two foci by means of different optical path difference, and further give the deterministic ratio of the two focal distances which attributes to their own generalized Fibonacci sequences. The generalized Fibonacci zone plates may allow for new applications in micro and nanophotonics.

  2. Transformation of Nonfunctioning Pancreatic Neuroendocrine Carcinoma Cells into Insulin Producing Cells after Treatment with Sunitinib

    Directory of Open Access Journals (Sweden)

    Jung Hun Ohn

    2013-06-01

    Full Text Available We report a rare case of severe hypoglycemia after sunitinib treatment for pancreatic neuroendocrine carcinoma. We describe the initial clinical presentation, laboratory results, pathologic findings, and managment in a patient with a nonfunctioning pancreatic neuroendocrine carcinoma with liver metastases who developed life threatening hypoglycemia after 2 months of sunitinib therapy. A 46-year-old woman presented to the emergency department with loss of consciousness from hypoglycemia. Serum C-peptide and insulin levels at fasting state revealed that the hypoglycemia resulted from endogenous hyperinsulinemia. She had been diagnosed with nonfunctioning pancreatic neuroendocrine carcinoma based on a biopsy of metastatic cervical lymph node and was being treated with sunitinib, a small molecule tyrosine kinase inhibitor. Immunohistochemical stain of the metastatic liver mass demonstrated that the initially nonfunctioning neuroendocrine carcinoma cells had changed into insulin-producing cells after sunitinib therapy. Transarterial chemoembolization of the liver masses and systemic chemotherapy with streptozotocin/adriamycin relieved the hypoglycemia. A nonfunctioning pancreatic neuroendocrine carcinoma was transformed into an insulin-producing tumor after treatment with sunitinib, causing endogenous hyperinsulinemia and severe hypoglycemia.

  3. Synergy effects of hybrid carbon system on properties of composite bipolar plates for fuel cells

    Science.gov (United States)

    Kim, Jong Wan; Kim, Nam Hoon; Kuilla, Tapas; Kim, Tae Jin; Rhee, Kyong Yop; Lee, Joong Hee

    A hybrid carbon system of graphite powder (GP) and continuous carbon fibre fabric (CFF) is used for an epoxy composite to improve the electrical conductivity, mechanical properties and mouldability of a composite bipolar plate. These improvements are achieved simultaneously by inserting several layers of CFF into the GP/epoxy composite to enhance the mechanical properties and in-plane conductivity. The electrical properties, flexural strength and mouldability of the composite plates are measured as a function of conducting filler content and number of CFF layers. The composites show improved electrical conductivity, flexural properties and mouldability. Composites with 70-75 vol.% carbon fillers have the highest electrical conductivity with reasonable flexural properties. These results suggest that the poor mouldability and low through-plane electrical conductivity of the continuous fibre composite bipolar plate, as well as the weak flexural properties of GP composites, can be overcome by incorporating a GP/CFF hybrid system.

  4. Origin of Matrix-Producing Cells That Contribute to Aortic Fibrosis in Hypertension.

    Science.gov (United States)

    Wu, Jing; Montaniel, Kim Ramil C; Saleh, Mohamed A; Xiao, Liang; Chen, Wei; Owens, Gary K; Humphrey, Jay D; Majesky, Mark W; Paik, David T; Hatzopoulos, Antonis K; Madhur, Meena S; Harrison, David G

    2016-02-01

    Various hypertensive stimuli lead to exuberant adventitial collagen deposition in large arteries, exacerbating blood pressure elevation and end-organ damage. Collagen production is generally attributed to resident fibroblasts; however, other cells, including resident and bone marrow-derived stem cell antigen positive (Sca-1(+)) cells and endothelial and vascular smooth muscle cells, can produce collagen and contribute to vascular stiffening. Using flow cytometry and immunofluorescence, we found that adventitial Sca-1(+) progenitor cells begin to produce collagen and acquire a fibroblast-like phenotype in hypertension. We also found that bone marrow-derived cells represent more than half of the matrix-producing cells in hypertension, and that one-third of these are Sca-1(+). Cell sorting and lineage-tracing studies showed that cells of endothelial origin contribute to no more than one fourth of adventitial collagen I(+) cells, whereas those of vascular smooth muscle lineage do not contribute. Our findings indicate that Sca-1(+) progenitor cells and bone marrow-derived infiltrating fibrocytes are major sources of arterial fibrosis in hypertension. Endothelial to mesenchymal transition likely also contributes, albeit to a lesser extent and pre-existing resident fibroblasts represent a minority of aortic collagen-producing cells in hypertension. This study shows that vascular stiffening represents a complex process involving recruitment and transformation of multiple cells types that ultimately elaborate adventitial extracellular matrix.

  5. Multinucleated Giant Cancer Cells Produced in Response to Ionizing Radiation Retain Viability and Replicate Their Genome

    Science.gov (United States)

    Mirzayans, Razmik; Andrais, Bonnie; Scott, April; Wang, Ying W.; Kumar, Piyush; Murray, David

    2017-01-01

    Loss of wild-type p53 function is widely accepted to be permissive for the development of multinucleated giant cells. However, whether therapy-induced multinucleation is associated with cancer cell death or survival remains controversial. Herein, we demonstrate that exposure of p53-deficient or p21WAF1 (p21)-deficient solid tumor-derived cell lines to ionizing radiation (between 2 and 8 Gy) results in the development of multinucleated giant cells that remain adherent to the culture dish for long times post-irradiation. Somewhat surprisingly, single-cell observations revealed that virtually all multinucleated giant cells that remain adherent for the duration of the experiments (up to three weeks post-irradiation) retain viability and metabolize 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT), and the majority (>60%) exhibit DNA synthesis. We further report that treatment of multinucleated giant cells with pharmacological activators of apoptosis (e.g., sodium salicylate) triggers their demise. Our observations reinforce the notion that radiation-induced multinucleation may reflect a survival mechanism for p53/p21-deficient cancer cells. With respect to evaluating radiosensitivity, our observations underscore the importance of single-cell experimental approaches (e.g., single-cell MTT) as the creation of viable multinucleated giant cells complicates the interpretation of the experimental data obtained by commonly-used multi-well plate colorimetric assays. PMID:28208747

  6. Single-step cloning-screening method: a new tool for developing and studying high-titer viral vector producer cells.

    Science.gov (United States)

    Rodrigues, A F; Formas-Oliveira, A S; Guerreiro, M R; Tomás, H A; Alves, P M; Coroadinha, A S

    2015-09-01

    This article describes a novel method merging the cloning of viral vector producer cells with vector titer screening, allowing for screening 200-500 clones in 2 weeks. It makes use of a GFP separated into two fragments, S10 and S11 (Split GFP), fluorescing only upon transcomplementation. Producer cells carrying a S11 viral transgene are cloned in 96-well plates and co-cultured with target cells stably expressing S10. During the period of clone expansion, S11 viruses infect S10 target cells reconstituting the GFP signal. Transcomplemented fluorescence data provide direct estimation of the clone's productivity and can be analyzed in terms of density distribution, offering valuable information on the average productivity of the cell population and allowing the identification of high-producing clones. The method was validated by establishing a retrovirus producer from a nude cell line, in <3 months, inserting three vector constructs without clone selection or screening in between. Clones producing up to 10(8) infectious particles per ml were obtained, delivering optimal ratios of infectious-to-total particles (1 to 5). The method was additionally used to evaluate the production performance of HEK 293 and HEK 293T cell lines demonstrating that the latter sustains increased titers. Finally, it was used to study genetic manipulation of glutathione metabolism in retrovirus production showing that changing cell metabolism steers higher vector expression with titer increases of more than one order of magnitude.This method is a valuable tool not only for cell line development but also for genetic manipulation of viral vector and/or producer cells contributing to advancing the field of viral gene therapy.

  7. CCR6 marks regulatory T cells as a colon-tropic, interleukin-10-producing phenotype1

    Science.gov (United States)

    Kitamura, Kazuya; Farber, Joshua M.; Kelsall, Brian L.

    2014-01-01

    Expression of CCR6 and its ligand, CCL20, are increased in the colon of humans with inflammatory bowel diseases and mice with experimental colits, however their role in disease pathogenesis remains obscure. Here we demonstrate a role for CCR6 on regulatory T (Treg)3 cells in the T cell-transfer model of colitis. Rag2−/− mice given Ccr6−/− CD4+CD45RBhigh T cells had more severe colitis with increased IFN-γ-producing T cells, compared to the mice given WT cells. While equivalent frequency of induced/acquired Treg (iTreg) cells was observed in mesenteric lymph nodes and colon from both groups, the suppressive capacity of Ccr6−/− iTreg cells was impaired. Co-transfer studies of WT or Ccr6−/− Treg cells with CD4+CD45RBhigh T cells also showed the defect of Ccr6−/− Treg cell suppression. CCR6+ Treg cells were characterized as antigen-activated and IL-10-producing in the steady state, and preferentially migrated to the colon during inflammation. Thus, we concludes that CCR6 expression on Treg cells was required for the full function of Treg cell-mediated suppression in the T cell-transfer model of colitis. CCR6 may contribute to the regulation of colitis via the recruitment of antigen-specific, IL-10-producing iTreg cells to the inflamed colon. PMID:20720211

  8. PEM fuel cells with injection moulded bipolar plates of highly filled graphite compounds; PEM-Brennstoffzellen mit spritzgegossenen Bipolarplatten aus hochgefuelltem Graphit-Compound

    Energy Technology Data Exchange (ETDEWEB)

    Kreuz, Can

    2008-04-11

    This work concerns with the injection moulding of highly filled graphite compounds to bipolar plates for PEM fuel cells in a power output range between 100 - 500 Watts. A particular focus is laid on the combination of the three multidisciplinary scopes like material development, production technology and component development / design. The results of the work are specified by the process-oriented characterisation of the developed and manufactured bipolar plates as well as their application in a functioning fuel cell. (orig.)

  9. Interleukin 17-Producing γδT Cells Increased in Patients with Active Pulmonary Tuberculosis

    Institute of Scientific and Technical Information of China (English)

    Meiyu Peng; Zhaohua Wang; Chunyan Yao; Lina Jiang; Qili Jin; Jing Wang; Baiqing Li

    2008-01-01

    Although it has been known that y8 T cells may play an important role in the immune response to infection of Mycobacterium tuberculosis (M. tb), the mechanisms by which the T8 T cells participate in the innate and/or acquired immunity to tuberculosis (TB) have not been full elucidated. In the present study, 27 patients with active pulmonary TB and 16 healthy donors (HD) were performed. We found that proportion of IL-17-producing cells among lymphocyte was similar between TB patients and HD, whereas the proportions of γδ T cells in IL-17- producing cells (59.2%) and IL-17-producing cells in γδ T cells (19.4%) in peripheral blood were markedly increased in TB patients when compared to those in HD (43.9% and 7.7%, respectively). In addition, the proportions of IFN-γ-producing γδ T cells in TB patients were obviously lower than that in HD. Upon re-stimulated with M. tb heat-treated antigen (M. tb-HAg) in vitro, fewer IL-17-producing γδ T cells were generated from HD and TB patients, whereas IFN-γ-producing γδ T cells were increased in TB patients compared to that in HD. Our findings in TB patients and healthy human were consistent with other murine investigation that the IL-17- producing γδ T cells were main source of IL-17 in mouse model of BCG infection, suggesting that γδ T cells might be involved in the formation of tubercular granuloma in pulmonary TB patients, but need further identification. Cellular & Molecular Immunology. 2008;5(3):203-208.

  10. Nickel Electroless Plating: Adhesion Analysis for Mono-Type Crystalline Silicon Solar Cells.

    Science.gov (United States)

    Shin, Eun Gu; Rehman, Atteq ur; Lee, Sang Hee; Lee, Soo Hong

    2015-10-01

    The adhesion of the front electrodes to silicon substrate is the most important parameters to be optimized. Nickel silicide which is formed by sintering process using a silicon substrate improves the mechanical and electrical properties as well as act as diffusion barrier for copper. In this experiment p-type mono-crystalline czochralski (CZ) silicon wafers having resistivity of 1.5 Ω·cm were used to study one step and two step nickel electroless plating process. POCl3 diffusion process was performed to form the emitter with the sheet resistance of 70 ohm/sq. The Six, layer was set down as an antireflection coating (ARC) layer at emitter surface by plasma enhanced chemical vapor deposition (PECVD) process. Laser ablation process was used to open SiNx passivation layer locally for the formation of the front electrodes. Nickel was deposited by electroless plating process by one step and two step nickel electroless deposition process. The two step nickel plating was performed by applying a second nickel deposition step subsequent to the first sintering process. Furthermore, the adhesion analysis for both one step and two steps process was conducted using peel force tester (universal testing machine, H5KT) after depositing Cu contact by light induced plating (LIP).

  11. Fli+ etsrp+ hemato-vascular progenitor cells proliferate at the lateral plate mesoderm during vasculogenesis in zebrafish.

    Directory of Open Access Journals (Sweden)

    Chang Zoon Chun

    Full Text Available BACKGROUND: Vasculogenesis, the de novo formation of blood vessels from precursor cells is critical for a developing embryo. However, the signals and events that dictate the formation of primary axial vessels remain poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we use ets-related protein-1 (etsrp, which is essential for vascular development, to analyze the early stages of vasculogenesis in zebrafish. We found etsrp(+ cells of the head, trunk and tail follow distinct developmental sequences. Using a combination of genetic, molecular and chemical approaches, we demonstrate that fli(+etsrp(+ hemato-vascular progenitors (FEVPs are proliferating at the lateral plate mesoderm (LPM. The Shh-VEGF-Notch-Hey2 signaling pathway controls the proliferation process, and experimental modulation of single components of this pathway alters etsrp(+ cell numbers at the LPM. CONCLUSIONS/SIGNIFICANCE: This study for the first time defines factors controlling proliferation, and cell numbers of pre-migratory FEVPs in zebrafish.

  12. Comparison of phenotype characteristics of rat annulus fibrosus cells cultured on flexible silicone membrane and in plastic plate

    Institute of Scientific and Technical Information of China (English)

    GUO Zhi-liang; CHENG Min; CAO Guo-yong; LI Hua-zhuang; TENG Hai-jun; ZHOU Yue

    2006-01-01

    Objective:To compare the phenotype characteristics of rat annulus fibrosus (AF) cells cultured on flexible silicone membranes and those in plastic plates. Methods :The morphology of AF cells cultured in different substrates was examined. Proteoglycan was stained by toluidine blue. Contents of collagen type I , collagen type Ⅱ and aggrecan mRNAs were determined by reverse transcription-polymerase chain reaction (RT-PCR). The expression of integrin β1 was monitored by flow cytometry. By using propidium iodide (PI), the cell cycle in AF cells was analyzed. Cell adhesion to silicone membrane was also measured. Results:The AF cells cultured on different substrates were morphologically undistinguishable.Toluidine blue staining showed that there was also no difference between AF cells cultured on these 2 substrates. They still had the same expression levels of collagen type Ⅰ , collagen type Ⅱ , aggrecan mRNAs,and integrin β1. No significant difference was observed in the distribution of the cell cycle. AF cells grew well on silicone membrane. Conclusion:AF cells cultured on flexible silicone membrane maintain the stability of phenotype and may be appropriate for further studying the metabolic responses to mechanical stimuli at the cellular level.

  13. Assessing the efficacy of endoscopic office olfactory biopsy sites to produce neural progenitor cell cultures for the study of neuropsychiatric disorders.

    Science.gov (United States)

    Wrobel, Bozena B; Mazza, Jill M; Evgrafov, Oleg V; Knowles, James A

    2013-02-01

    The olfactory region is capable of continuous neurogenesis. Situated on the cribriform plate and segments of the superior septum and both superior and middle turbinates, it is accessible through office-based biopsy and can be used to generate neural progenitor cells to study molecular abnormalities associated with neuropsychiatric disorders. The purpose of the study was to evaluate the efficacy of the endoscopic office olfactory biopsy from middle turbinate and superior-posterior septum to produce the neural progenitor cells. Endoscopic office-based biopsy samples were collected and cultured neuronal cells derived from olfactory neuroepithelium (CNON) were established from 40 healthy individuals and 40 schizophrenia patients. All patients underwent biopsies of both the middle turbinate and the superior-posterior septum. Specific culture conditions promoted the growth of neural progenitor cells from these biopsy sites. CNON cultures were established from such outgrowing neuronal cells. The study was institutional review board (IRB)-approved and informed consent was obtained. Cultures were successfully developed from 98.8% of participants. No complications were observed. The single, unsuccessful specimen failed to grow any cell types due to tissue mishandling. Overall, we have observed no significant difference in the effectiveness of biopsy from middle turbinate and superior-posterior septum to produce neural progenitor cells. The middle turbinate biopsies contain viable neural progenitor cells capable of generating neuronal cell cultures. Thus technically more simple biopsy of the middle turbinate can be used to propagate neural progenitor cells. © 2013 ARS-AAOA, LLC.

  14. LS14: a novel human adipocyte cell line that produces prolactin.

    Science.gov (United States)

    Hugo, Eric R; Brandebourg, Terry D; Comstock, Clay E S; Gersin, Keith S; Sussman, Jeffrey J; Ben-Jonathan, Nira

    2006-01-01

    Adipose tissue is an integral component within the endocrine system. Adipocytes produce numerous bioactive substances, and their dysregulation has serious pathophysiological consequences. We previously reported that human adipose tissue from several depots produces significant amounts of prolactin (PRL). To study locally produced PRL, we sought an acceptable in vitro model. Consequently, we developed an adipocyte cell line derived from a metastatic liposarcoma. The cell line, designated LS14, has been in continuous culture for 2 yr. These cells exhibit many properties of primary preadipocytes, including the ability to undergo terminal differentiation, as judged by morphological alterations, lipid accumulation, and increase in glycerol-3-phosphate dehydrogenase. LS14 cells express many adipose-associated genes, such as adipocyte fatty acid-binding protein (aP(2)), hormone-sensitive lipase, lipoprotein lipase, preadipocyte factor 1, adiponectin, leptin, and IL-6. Similar to primary adipocytes, LS14 cells also produce and respond to PRL, thus making them an attractive model to study adipose PRL production and function. The expression of PRL was confirmed at the transcriptional level by RT-PCR, and PRL secretion was determined by the Nb2 bioassay. Addition of exogenous PRL to LS14 cells resulted in a dose-dependent inhibition of IL-6 release. In summary, we have established a novel human adipocyte cell line with many characteristics of primary adipocytes. The LS14 cells open up new avenues for research on human adipocyte biology and add to the repertoire of nonpituitary, PRL-producing cell lines.

  15. Producing recombinant therapeutic glycoproteins with enhanced sialylation using CHO-gmt4 glycosylation mutant cells

    Science.gov (United States)

    Goh, John SY; Liu, Yingwei; Chan, Kah Fai; Wan, Corrine; Teo, Gavin; Zhang, Peiqing; Zhang, Yuanxing; Song, Zhiwei

    2014-01-01

    Recombinant glycoprotein drugs require proper glycosylation for optimal therapeutic efficacy. Glycoprotein therapeutics are rapidly removed from circulation and have reduced efficacy if they are poorly sialylated. Ricinus communis agglutinin-I (RCA-I) was found highly toxic to wild-type CHO-K1 cells and all the mutants that survived RCA-I treatment contained a dysfunctional N-acetylglucosaminyltransferase I (GnT I) gene. These mutants are named CHO-gmt4 cells. Interestingly, upon restoration of GnT I, the sialylation of a model glycoprotein, erythropoietin, produced in CHO-gmt4 cells was shown to be superior to that produced in wild-type CHO-K1 cells. This addendum summarizes the applicability of this cell line, from transient to stable expression of the recombinant protein, and from a lab scale to an industrial scale perfusion bioreactor. In addition, CHO-gmt4 cells can be used to produce glycoproteins with mannose-terminated N-glycans. Recombinant glucocerebrosidase produced by CHO-gmt4 cells will not require glycan remodeling and may be directly used to treat patients with Gaucher disease. CHO-gmt4 cells can also be used to produce other glycoprotein therapeutics which target cells expressing mannose receptors. PMID:24911584

  16. Ethanol exposure disrupts extraembryonic microtubule cytoskeleton and embryonic blastomere cell adhesion, producing epiboly and gastrulation defects

    Directory of Open Access Journals (Sweden)

    Swapnalee Sarmah

    2013-08-01

    Fetal alcohol spectrum disorder (FASD occurs when pregnant mothers consume alcohol, causing embryonic ethanol exposure and characteristic birth defects that include craniofacial, neural and cardiac defects. Gastrulation is a particularly sensitive developmental stage for teratogen exposure, and zebrafish is an outstanding model to study gastrulation and FASD. Epiboly (spreading blastomere cells over the yolk cell, prechordal plate migration and convergence/extension cell movements are sensitive to early ethanol exposure. Here, experiments are presented that characterize mechanisms of ethanol toxicity on epiboly and gastrulation. Epiboly mechanisms include blastomere radial intercalation cell movements and yolk cell microtubule cytoskeleton pulling the embryo to the vegetal pole. Both of these processes were disrupted by ethanol exposure. Ethanol effects on cell migration also indicated that cell adhesion was affected, which was confirmed by cell aggregation assays. E-cadherin cell adhesion molecule expression was not affected by ethanol exposure, but E-cadherin distribution, which controls epiboly and gastrulation, was changed. E-cadherin was redistributed into cytoplasmic aggregates in blastomeres and dramatically redistributed in the extraembryonic yolk cell. Gene expression microarray analysis was used to identify potential causative factors for early development defects, and expression of the cell adhesion molecule protocadherin-18a (pcdh18a, which controls epiboly, was significantly reduced in ethanol exposed embryos. Injecting pcdh18a synthetic mRNA in ethanol treated embryos partially rescued epiboly cell movements, including enveloping layer cell shape changes. Together, data show that epiboly and gastrulation defects induced by ethanol are multifactorial, and include yolk cell (extraembryonic tissue microtubule cytoskeleton disruption and blastomere adhesion defects, in part caused by reduced pcdh18a expression.

  17. A novel IL-10-producing innate lymphoid cells (ILC10) in a contact hypersensitivity mouse model

    Science.gov (United States)

    Kim, Hyuk Soon; Jang, Jong-Hwa; Lee, Min Bum; Jung, In Duk; Park, Yeong-Min; Kim, Young Mi; Choi, Wahn Soo

    2016-01-01

    The immunoregulatory cytokine Interleukin 10 (IL-10) protein is produced by various cells during the course of inflammatory disorders. Mainly, it downregulates pro-inflammatory cytokines, antigen presentation, and helper T cell activation. In this study, we show that the ratio of IL-10-producing cells was significantly increased in lineage negative (i.e., not T, B, or leukocyte cell lineages) cells than in lineage positive cells in lymphoid and peripheral tissues. We further observed that IL-10-producing innate lymphoid cells (ILCs), here called firstly ILC10, were increased in number in oxazolone-induced contact hypersensitivity (CHS) mice. In detail, IL-10-producing lineage negative cells were elevated in the axillary, inguinal lymph node, and ear tissues of CHS mice. Notably, the cells expressed classical ILC marker proteins such as CD45, CD127, and Sca-1. Altogether, our findings suggest for the first time that ILC10s are present in various physiological settings and could be involved in numerous immune responses as regulatory cells. [BMB Reports 2016; 49(5): 293-296] PMID:26949018

  18. An experimental and theoretical approach to the study of the photoacoustic signal produced by cancer cells

    Directory of Open Access Journals (Sweden)

    Rafael Pérez Solano

    2012-03-01

    Full Text Available The distinctive spectral absorption characteristics of cancer cells make photoacoustic techniques useful for detection in vitro and in vivo. Here we report on our evaluation of the photoacoustic signal produced by a series of monolayers of different cell lines in vitro. Only the melanoma cell line HS936 produced a detectable photoacoustic signal in which amplitude was dependent on the number of cells. This finding appears to be related to the amount of melanin available in these cells. Other cell lines (i.e. HL60, SK-Mel-1, T47D, Hela, HT29 and PC12 exhibited values similar to a precursor of melanin (tyrosinase, but failed to produce sufficient melanin to generate a photoacoustic signal that could be distinguished from background noise. To better understand this phenomenon, we determined a formula for the time-domain photoacoustic wave equation for a monolayer of cells in a non-viscous fluid on the thermoelastic regime. The theoretical results showed that the amplitude and profile of the photoacoustic signal generated by a cell monolayer depended upon the number and distribution of the cells and the location of the point of detection. These findings help to provide a better understanding of the factors involved in the generation of a photoacoustic signal produced by different cells in vitro and in vivo.

  19. Preparation and properties of thin epoxy/compressed expanded graphite composite bipolar plates for proton exchange membrane fuel cells

    Science.gov (United States)

    Du, Chao; Ming, Pingwen; Hou, Ming; Fu, Jie; Shen, Qiang; Liang, Dong; Fu, Yunfeng; Luo, Xiaokuan; Shao, Zhigang; Yi, Baolian

    Although the composite bipolar plates prepared by the method of the vacuum resin impregnation in compressed expanded graphite (CEG) sheets have been applied in the KW-class stacks, there have been few investigations of the preparation and properties of them so far. In this research, the influences of the microstructure on the physical properties of the thin epoxy/CEG composites (the thickness is 1 mm) are investigated for the first time and the optimum preparation conditions are obtained. Results demonstrated that the mechanical property and the impermeability of the composites increases evidently with the resin content changing from 4% to 30%, while the electrical properties keep nearly constant. It can be attributed to the continuous expanded graphite (EG) conductive network of the raw CEG sheet. The epoxy (30 wt.%)/CEG composite is shown to be the optimum composite, displaying in-plane conductivity of 119.8 S cm -1, through-plane resistance of 17.13 mΩ cm 2, density of 1.95 g cm -3, gas permeability of 1.94 × 10 -6 cm 3 cm -2 s -1 and flexural strength of 45.8 MPa. The alcohol scrubbing is the optimum method of surface post-processing. The performance of a single cell with the optimum composite bipolar plates is tested and demonstrated to be outstanding. Above all, the composite prepared by resin vacuum impregnation in the CEG sheet is a promising candidate for bipolar plate materials in PEMFCs.

  20. The economic payoff for a state-of-the-art high-efficiency flat-plate crystalline silicon solar cell technology

    Science.gov (United States)

    Bickler, Donald B.; Callaghan, W. T.

    In 1986 during the flat-plate solar array project, silicon solar cells 4.0 sq cm in area were fabricated at the Jet Propulsion Laboratory (JPL) with a conversion efficiency of 20.1 percent (AM1.5-global). Sixteen cells were processed with efficiencies measuring 19.5 percent (AM1.5 global) or better. These cells were produced using refined versions of conventional processing methods, aside from certain advanced techniques that bring about a significant reduction in a major mechanism (surface recombination) that limits cell efficiency. Wacker Siltronic p-type float-zone 0.18-ohm-cm wafers were used. Conversion efficiencies in this range have previously been reported by other researchers, but generally on much smaller (0.5 vs. 4.0 cm) devices which have undergone sophisticated and costly processing steps. An economic analysis is presented of the potential payoffs for this approach, using the Solar Array Manufacturing Industry Costing Standards (SAMICS) methodology. The process sequence used and the assumptions made for capturing the economies of scale are presented.

  1. Design of a cone-and-plate device for controlled realistic shear stress stimulation on endothelial cell monolayers.

    Science.gov (United States)

    Franzoni, Marco; Cattaneo, Irene; Ene-Iordache, Bogdan; Oldani, Alberto; Righettini, Paolo; Remuzzi, Andrea

    2016-10-01

    Endothelial cells are constantly exposed to blood flow and the resulting frictional force, the wall shear stress, varies in magnitude and direction with time, depending on vasculature geometry. Previous studies have shown that the structure and function of endothelial cells, and ultimately of the vessel wall, are deeply affected by the nature of wall shear stress waveforms. To investigate the in vitro effects of these stimuli, we developed a compact, programmable, real-time operated system based on cone-and-plate geometry, that can be used within a standard cell incubator. To verify the capability to replicate realistic shear stress waveforms, we calculated both analytically and numerically to what extent the system is able to correctly deliver the stimuli defined by the user at plate level. Our results indicate that for radii greater than 25 mm, the shear stress is almost uniform and directly proportional to cone rotation velocity. We further established that using a threshold of 10 Hz of wall shear stress waveform frequency components, oscillating flow conditions can be reproduced on cell monolayer surface. Finally, we verified the capability of the system to perform long-term flow exposure experiments ensuring sterility and cell culture viability on human umbilical vein endothelial cells exposed to unidirectional and oscillating shear stress. In conclusion, the system we developed is a highly dynamic, easy to handle, and able to generate pulsatile and unsteady oscillating wall shear stress waveforms. This system can be used to investigate the effects of realistic stimulations on endothelial cells, similar to those exerted in vivo by blood flow.

  2. FCHSD1 and FCHSD2 are expressed in hair cell stereocilia and cuticular plate and regulate actin polymerization in vitro.

    Directory of Open Access Journals (Sweden)

    Huiren Cao

    Full Text Available Mammalian FCHSD1 and FCHSD2 are homologous proteins containing an amino-terminal F-BAR domain and two SH3 domains near their carboxyl-termini. We report here that FCHSD1 and FCHSD2 are expressed in mouse cochlear sensory hair cells. FCHSD1 mainly localizes to the cuticular plate, whereas FCHSD2 mainly localizes along the stereocilia in a punctuate pattern. Nervous Wreck (Nwk, the Drosophila ortholog of FCHSD1 and FCHSD2, has been shown to bind Wsp and play an important role in F-actin assembly. We show that, like its Drosophila counterpart, FCHSD2 interacts with WASP and N-WASP, the mammalian orthologs of Drosophila Wsp, and stimulates F-actin assembly in vitro. In contrast, FCHSD1 doesn't bind WASP or N-WASP, and can't stimulate F-actin assembly when tested in vitro. We found, however, that FCHSD1 binds via its F-BAR domain to the SH3 domain of Sorting Nexin 9 (SNX9, a well characterized BAR protein that has been shown to promote WASP-Arp2/3-dependent F-actin polymerization. FCHSD1 greatly enhances SNX9's WASP-Arp2/3-dependent F-actin polymerization activity. In hair cells, SNX9 was detected in the cuticular plate, where it colocalizes with FCHSD1. Our results suggest that FCHSD1 and FCHSD2 could modulate F-actin assembly or maintenance in hair cell stereocilia and cuticular plate.

  3. Pregnancy close to the edge: an immunosuppressive infiltrate in the chorionic plate of placentas from uncomplicated egg cell donation.

    Science.gov (United States)

    Schonkeren, Dorrith; Swings, Godelieve; Roberts, Drucilla; Claas, Frans; de Heer, Emile; Scherjon, Sicco

    2012-01-01

    In pregnancies achieved after egg donation (ED) tolerance towards a completely allogeneic fetus is mediated by several complex immunoregulatory mechanisms, of which numerous aspects are still unknown. A distinct lesion not described previously in the literature, was repeatedly found in the chorionic plate in a substantial portion of placentas from ED pregnancies, but never in placentas from normal term pregnancies. The aim of this study was to assess its origin and its cellular composition. The relation between the lesion, the clinical and histological parameters were assessed. In addition we investigated the relation with the number of HLA-mismatches and KIR genotype of mother and child.In ten out of twenty-six (38.5%) placentas from ED pregnancies an inflammatory lesion was present in the chorionic plate. A significantly lower incidence of pre-eclampsia was found in the group with the lesion; 0% versus 45.5%. A significant relation was found between this lesion and the presence of intervillositis, chronic deciduitis, presence of plasma cells and fibrin deposition in the decidua. Fluorescent in situ hybridisation with X/Y-chromosome probes showed that the majority of cells present in the lesion are of maternal origin. The expression of the macrophage marker CD14+ and of the type 2 macrophage (M2) marker CD163+ was significantly higher in the lesion. The incidence of a fetal HLA-C2 genotype was significantly higher in cases with a lesion compared to the group without the lesion. In conclusion, a striking relationship was observed between the presence of a not previously described inflammatory lesion in the chorionic plate and the absence of pre-eclampsia in ED pregnancies. The lesion consists of mainly maternal cells with a higher expression of the macrophage marker CD14+ and the M2 marker CD163+. These findings suggest a protective immune mechanism which might contribute to the prevention of severe clinical complications like pre-eclampsia.

  4. Pregnancy close to the edge: an immunosuppressive infiltrate in the chorionic plate of placentas from uncomplicated egg cell donation.

    Directory of Open Access Journals (Sweden)

    Dorrith Schonkeren

    Full Text Available In pregnancies achieved after egg donation (ED tolerance towards a completely allogeneic fetus is mediated by several complex immunoregulatory mechanisms, of which numerous aspects are still unknown. A distinct lesion not described previously in the literature, was repeatedly found in the chorionic plate in a substantial portion of placentas from ED pregnancies, but never in placentas from normal term pregnancies. The aim of this study was to assess its origin and its cellular composition. The relation between the lesion, the clinical and histological parameters were assessed. In addition we investigated the relation with the number of HLA-mismatches and KIR genotype of mother and child.In ten out of twenty-six (38.5% placentas from ED pregnancies an inflammatory lesion was present in the chorionic plate. A significantly lower incidence of pre-eclampsia was found in the group with the lesion; 0% versus 45.5%. A significant relation was found between this lesion and the presence of intervillositis, chronic deciduitis, presence of plasma cells and fibrin deposition in the decidua. Fluorescent in situ hybridisation with X/Y-chromosome probes showed that the majority of cells present in the lesion are of maternal origin. The expression of the macrophage marker CD14+ and of the type 2 macrophage (M2 marker CD163+ was significantly higher in the lesion. The incidence of a fetal HLA-C2 genotype was significantly higher in cases with a lesion compared to the group without the lesion. In conclusion, a striking relationship was observed between the presence of a not previously described inflammatory lesion in the chorionic plate and the absence of pre-eclampsia in ED pregnancies. The lesion consists of mainly maternal cells with a higher expression of the macrophage marker CD14+ and the M2 marker CD163+. These findings suggest a protective immune mechanism which might contribute to the prevention of severe clinical complications like pre-eclampsia.

  5. Appearance of actin microfilament 'twin peaks' in mitosis and their function in cell plate formation, as visualized in tobacco BY-2 cells expressing GFP-fimbrin.

    Science.gov (United States)

    Sano, Toshio; Higaki, Takumi; Oda, Yoshihisa; Hayashi, Tomomi; Hasezawa, Seiichiro

    2005-11-01

    The actin cytoskeleton of higher plants plays an essential role in plant morphogenesis and in maintaining various cellular activities. In this study we established a tobacco BY-2 cell line, stably transformed with a GFP-fimbrin actin-binding domain (ABD) 2 construct, that allows visualization of actin microfilaments (MFs) in living cells. Using this cell line, designated BY-GF11, we performed time-sequential observations of MF dynamics during cell-cycle progression. Detailed analyses revealed the appearance of a broad MF band in the late G2 phase that separated to form a structure corresponding to the so-called actin-depleted zone (ADZ) in mitosis. In BY-GF11, the MF structure at the cell cortex in mitosis appeared to form two bands rather than the ADZ. Measurements of fluorescent intensities of the cell cortex indicated an MF distribution that resembled two peaks, and we therefore named the structure MF 'twin peaks' (MFTP). The cell plate formed exactly within the valley between the MFTP at cytokinesis, and this cell-plate guidance was distorted by disruption of the MFTP by an inhibitor of actin polymerization. These results suggest that the MFTP originates from the broad MF band in the G2 phase and functions as a marker of cytokinesis.

  6. Endovascular Method for Transplantation of Insulin-Producing Cells to the Pancreas Parenchyma in Swine

    OpenAIRE

    Lundberg, J.; Stone-Elander, S.; Zhang, X. -M; Korsgren, Olle; Jonsson, S; Holmin, S.

    2014-01-01

    Insulin-producing cells are transplanted by portal vein injection as an alternative to pancreas transplantation in both clinical and preclinical trials. Two of the main limitations of portal vein transplantation are the prompt activation of the innate immunity and concomitant loss of islets and a small but significant risk of portal vein thrombosis. Furthermore, to mimic physiological release, the insulin-producing cells should instead be located in the pancreas. The trans-vessel wall approac...

  7. Quantitative studies of the gastrin-producing cells of the human antrum. A methodological study

    DEFF Research Database (Denmark)

    Nielsen, H O; Halken, S; Lorentzen, M

    1980-01-01

    The antral gastrin-producing cells (G-cells) have been identified by the indirect immunoperoxidase technique in two antrum preparations removed due to a recurrent duodenal and gastric ulcer. Morphometric principles were applied to the G-cells with determination of their volume density, numerical ....... A method for estimating the total G-cell population and the total G-cell volume in the antrum was developed. In the antrum removed due to a gastric ulcer the number of G-cells was 190 x 10(6) and their total volume 176 mm3....

  8. Quantitative studies of the gastrin-producing cells of the human antrum. A methodological study

    DEFF Research Database (Denmark)

    Nielsen, H O; Halken, S; Lorentzen, M

    1980-01-01

    The antral gastrin-producing cells (G-cells) have been identified by the indirect immunoperoxidase technique in two antrum preparations removed due to a recurrent duodenal and gastric ulcer. Morphometric principles were applied to the G-cells with determination of their volume density, numerical....... A method for estimating the total G-cell population and the total G-cell volume in the antrum was developed. In the antrum removed due to a gastric ulcer the number of G-cells was 190 x 10(6) and their total volume 176 mm3....

  9. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten; Camilli, Luca; Spiegelhauer, Susie Ann

    2015-01-01

    /SS, both samples exhibiting a similar trend, thus questioning the short-term positive effect of graphene coatings. However, partial immersion in boiling seawater for three weeks reveals a clear superiority of the graphene coating with respect to steel just protected by Ni. After the test, the graphene film......Abstract Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel...

  10. Fluorometric assessment of acetaminophen-induced toxicity in rat hepatocyte spheroids seeded on micro-space cell culture plates.

    Science.gov (United States)

    Sanoh, Seigo; Santoh, Masataka; Takagi, Masashi; Kanayama, Tatsuya; Sugihara, Kazumi; Kotake, Yaichiro; Ejiri, Yoko; Horie, Toru; Kitamura, Shigeyuki; Ohta, Shigeru

    2014-09-01

    Hepatotoxicity induced by the metabolic activation of drugs is a major concern in drug discovery and development. Three-dimensional (3-D) cultures of hepatocyte spheroids may be superior to monolayer cultures for evaluating drug metabolism and toxicity because hepatocytes in spheroids maintain the expression of various metabolizing enzymes and transporters, such as cytochrome P450 (CYP). In this study, we examined the hepatotoxicity due to metabolic activation of acetaminophen (APAP) using fluorescent indicators of cell viability and intracellular levels of glutathione (GSH) in rat hepatocyte spheroids grown on micro-space cell culture plates. The mRNA expression levels of some drug-metabolizing enzymes were maintained during culture. Additionally, this culture system was compatible with microfluorometric imaging under confocal laser scanning microscopy. APAP induced a decrease in intracellular ATP at 10mM, which was blocked by the CYP inhibitor 1-aminobenzotriazole (ABT). APAP (10mM, 24h) decreased the levels of both intracellular ATP and GSH, and GSH-conjugated APAP (APAP-GSH) were formed. All three effects were blocked by ABT, confirming a contribution of APAP metabolic activation by CYP to spheroid toxicity. Fluorometric imaging of hepatocyte spheroids on micro-space cell culture plates may allow the screening of drug-induced hepatotoxicity during pharmaceutical development.

  11. Analysis of the Optical Properties of Screen-Printed and Aerosol-Printed and Plated Fingers of Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    R. Woehl

    2008-01-01

    Full Text Available One main efficiency loss in industrial solar cells is the shading of the cell caused by the metal front side contacts. With the aerosol-printing technique plus an additional light-induced plating (LIP step, not only is the geometrical contact width narrowed compared to screen-printed contacts but also the shape of the finger changes. In this work, the effective shading of different finger types is analysed with two different measurement methods. The essential parameter for characterising the finger is the effective width which can be reduced drastically compared to the geometrical width due to total internal reflection at the glass-air layer and the reflection from the roundish edges of the contact fingers into the cell. This parameter was determined with different methods. It could be shown that for aerosol-printed fingers the effective (optical width is only 38% of its geometrical width, while for standard screen-printed fingers it is 47%. The measured values are compared to a theoretical model for an aerosol-printed and plated finger and are in good agreement.

  12. Improving tribological properties of (Zn–Ni)/nano Al{sub 2}O{sub 3} composite coatings produced by ultrasonic assisted pulse plating

    Energy Technology Data Exchange (ETDEWEB)

    Ataie, Sayed Alireza, E-mail: ataie_s_alireza@metaleng.iust.ac.ir; Zakeri, Alireza

    2016-07-25

    In this study pulse electroplating was used to deposit the composite coating of (Zn–Ni) strengthened by Al{sub 2}O{sub 3} nanoparticles on mild steel plate. The effect of Al{sub 2}O{sub 3} fraction and ultrasonic irradiation on the properties of the composite coating was also investigated. Scanning electron microscopy and energy dispersive spectroscopy techniques were employed to characterize the morphology and composition of the coating. Topography and surface roughness were investigated by atomic force microscopy. Also in order to evaluate the mechanical properties of the coating micro hardness and wear tests were conducted. It was found that coating hardness was increased from 538 HV to 750 HV and friction coefficient was decreased from 0.588 to 0.392. Results revealed that tribological properties of coating could be improved significantly by using suitable ultrasonic intensity simultaneously with pulse plating. - Highlights: • SEM indicated on the elimination of cracks and pores when ultrasounds were used. • XRD result showed nano sized grains of Zn–Ni matrix was developed in this research. • Simultaneous pulse plating and ultrasonic conditions improved the properties of the coating. • A (Zn–Ni)/nano alumina uniform composite coating for especial applications was developed. • Micro hardness and wear behavior of the coating was modified by intensifying the ultrasound.

  13. Cellular therapies based on stem cells and their insulin-producing surrogates: a 2015 reality check.

    Science.gov (United States)

    Giannoukakis, Nick; Trucco, Massimo

    2015-05-01

    Stem cell technology has recently gained a substantial amount of interest as one method to create a potentially limitless supply of transplantable insulin-producing cells to treat, and possibly cure diabetes mellitus. In this review, we summarize the state-of-the art of stem cell technology and list the potential sources of stem cells that have been shown to be useful as insulin-expressing surrogates. We also discuss the milestones that have been reached and those that remain to be addressed to generate bona fide beta cell-similar, insulin-producing surrogates. The caveats, limitations, and realistic expectations are also considered for current and future technology. In spite of the tremendous technical advances realized in the past decade, especially in the field of reprogramming adult somatic cells to become stem cells, the state-of-the art still relies on lengthy and cumbersome in vitro culture methods that yield cell populations that are not particularly glucose-responsive when transplanted into diabetic hosts. Despite the current impediments toward clinical translation, including the potential for immune rejection, the availability of technology to generate patient-specific reprogrammable stem cells has, and will be critical for, important insights into the genetics, epigenetics, biology, and physiology of insulin-producing cells in normal and pathologic states. This knowledge could accelerate the time to reach the desired breakthrough for safe and efficacious beta cell surrogates.

  14. Mechanical influence of tissue culture plates and extracellular matrix on mesenchymal stem cell behavior: A topical review.

    Science.gov (United States)

    Tatullo, Marco; Marrelli, Massimo; Falisi, Giovanni; Rastelli, Claudio; Palmieri, Francesca; Gargari, Marco; Zavan, Barbara; Paduano, Francesco; Benagiano, Vincenzo

    2016-03-01

    Tissue engineering applications need a continuous development of new biomaterials able to generate an ideal cell-extracellular matrix interaction. The stem cell fate is regulated by several factors, such as growth factors or transcription factors. The most recent literature has reported several publications able to demonstrate that environmental factors also contribute to the regulation of stem cell behavior, leading to the opinion that the environment plays the major role in the cell differentiation.The interaction between mesenchymal stem cells (MSCs) and extracellular environment has been widely described, and it has a crucial role in regulating the cell phenotype. In our laboratory (Tecnologica Research Institute, Crotone, Italy), we have recently studied how several physical factors influence the distribution and the morphology of MSCs isolated from dental pulp, and how they are able to regulate stem cell differentiation. Mechanical and geometrical factors are only a small part of the environmental factors able to influence stem cell behavior, however, this influence should be properly known: in fact, this assumption must be clearly considered during those studies involving MSCs; furthermore, these interactions should be considered as an important bias that involves an high number of studies on the MSCs, since in worldwide laboratories the scientists mostly use tissue culture plates for their experiments.

  15. Multifunctional polymeric nanocomposites fabricated by incorporation of exfoliated graphene nanoplatelets and their application in bipolar plates for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Jiang, Xian

    The focus of this research is to investigate the potential of using exfoliated graphene nanoplatelets, GNP, as the multifunctional nano-reinforcement in fabricating polymer/GNP nanocomposites and then explore their prospective applications in bipolar plates for polymer electrolyte membrane (PEM) fuel cells. Firstly, HDPE (high density polyethylene)/GNP nanocomposites were fabricated using the conventional compounding method of melt-extrusion followed by injection molding. The mechanical properties, crystallization behaviors, thermal stability, thermal conductivity, and electrical conductivity of the resulting HDPE/GNP nanocomposites were evaluated as a function of GNP concentration. Results showed that HDPE/GNP nanocomposites exhibit equivalent flexural modulus and strength to HDPE composites filled with other commercial reinforcements but they have superior impact strength. By investigating the crystallization behavior of HDPE/GNP nanocomposites, it was found that GNP is a good nucleating agent at low loading levels and as a result can significantly increase crystallization temperature and crystallinity of HDPE. At high GNP loadings, however, the close proximity of GNP particles retards the crystallization process. The thermal stability and thermal conductivity of HDPE/GNP nanocomposites were significantly enhanced due to the excellent thermal properties of GNP. Meanwhile, results indicated that the percolation threshold of these nanocomposites prepared by the conventional melt-extrusion and injection molding is relatively high at around 10--15 vol% GNP loading. To enhance the electrical conductivity of HDPE/GNP nanocomposites, two special processing methods named solid state ball milling (SSBM) and solid state shear pulverization (SSSP) were studied. The mechanism by which SSBM and SSSP are capable of producing lower percolation or higher electrical conductivity is to coat the polymer surface by GNP platelets which facilitate the formation of conductive networks

  16. Effect of filler content on the properties of expanded- graphite-based composite bipolar plates for application in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Masand, Aakash; Borah, Munu; Pathak, Abhishek K.; Dhakate, Sanjay R.

    2017-09-01

    Minimization of the weight and volume of a hydrogen-based PEM fuel cell stack is an essential area of research for the development and commercialization of PEMFCs for various applications. Graphite-based composite bipolar plates have significant advantages over conventional metallic bipolar plates due to their corrosion resistivity and low cost. On the other hand, expanded graphite is seen to be a potential candidate for facilitating the required electrical, thermal and mechanical properties of bipolar plates with a low density. Therefore, in the present study, the focus is on minimization of the high loading of graphite and optimizes its composition to meet the target properties of bipolar plates as per the USDOE target. Three types of expanded graphite (EG)-phenolic-resin-based composite bipolar plates were developed by partially replacing the expanded graphite content with natural graphite (NG) and carbon black as an additional filler. The three types of composite plate with the reinforcing constituent ratio EG:NG:R (25:25:50) give a bending strength of 49 MPa, a modulus of ~6 GPa, electrical conductivity  >100 S cm‑1, a shore hardness of 55 and a bulk density of 1.55 g/cc. The 50 wt% loading of resin is sufficient to wet the 50 wt% filler content in the composite plate. This study gives an insight into using hybrid reinforcements in order to achieve the desired properties of bipolar plates.

  17. IL-35-producing B cells are critical regulators of immunity during autoimmune and infectious diseases.

    Science.gov (United States)

    Shen, Ping; Roch, Toralf; Lampropoulou, Vicky; O'Connor, Richard A; Stervbo, Ulrik; Hilgenberg, Ellen; Ries, Stefanie; Dang, Van Duc; Jaimes, Yarúa; Daridon, Capucine; Li, Rui; Jouneau, Luc; Boudinot, Pierre; Wilantri, Siska; Sakwa, Imme; Miyazaki, Yusei; Leech, Melanie D; McPherson, Rhoanne C; Wirtz, Stefan; Neurath, Markus; Hoehlig, Kai; Meinl, Edgar; Grützkau, Andreas; Grün, Joachim R; Horn, Katharina; Kühl, Anja A; Dörner, Thomas; Bar-Or, Amit; Kaufmann, Stefan H E; Anderton, Stephen M; Fillatreau, Simon

    2014-03-20

    B lymphocytes have critical roles as positive and negative regulators of immunity. Their inhibitory function has been associated primarily with interleukin 10 (IL-10) because B-cell-derived IL-10 can protect against autoimmune disease and increase susceptibility to pathogens. Here we identify IL-35-producing B cells as key players in the negative regulation of immunity. Mice in which only B cells did not express IL-35 lost their ability to recover from the T-cell-mediated demyelinating autoimmune disease experimental autoimmune encephalomyelitis (EAE). In contrast, these mice displayed a markedly improved resistance to infection with the intracellular bacterial pathogen Salmonella enterica serovar Typhimurium as shown by their superior containment of the bacterial growth and their prolonged survival after primary infection, and upon secondary challenge, compared to control mice. The increased immunity found in mice lacking IL-35 production by B cells was associated with a higher activation of macrophages and inflammatory T cells, as well as an increased function of B cells as antigen-presenting cells (APCs). During Salmonella infection, IL-35- and IL-10-producing B cells corresponded to two largely distinct sets of surface-IgM(+)CD138(hi)TACI(+)CXCR4(+)CD1d(int)Tim1(int) plasma cells expressing the transcription factor Blimp1 (also known as Prdm1). During EAE, CD138(+) plasma cells were also the main source of B-cell-derived IL-35 and IL-10. Collectively, our data show the importance of IL-35-producing B cells in regulation of immunity and highlight IL-35 production by B cells as a potential therapeutic target for autoimmune and infectious diseases. This study reveals the central role of activated B cells, particularly plasma cells, and their production of cytokines in the regulation of immune responses in health and disease.

  18. Cerebellar stem cells do not produce neurons and astrocytes in adult mouse

    Energy Technology Data Exchange (ETDEWEB)

    Su, Xin; Guan, Wuqiang; Yu, Yong-Chun; Fu, Yinghui, E-mail: fuyh@fudan.edu.cn

    2014-07-18

    Highlights: • No new neurons and astrocytes are generated in adult mouse cerebellum. • Very few mash1{sup +} or nestin{sup +} stem cells exist, and most of them are quiescent. • Cell proliferation rate is diversified among cerebellar regions and decreases over time. - Abstract: Although previous studies implied that cerebellar stem cells exist in some adult mammals, little is known about whether these stem cells can produce new neurons and astrocytes. In this study by bromodeoxyuridine (BrdU) intraperitoneal (i.p.) injection, we found that there are abundant BrdU{sup +} cells in adult mouse cerebellum, and their quantity and density decreases significantly over time. We also found cell proliferation rate is diversified in different cerebellar regions. Among these BrdU{sup +} cells, very few are mash1{sup +} or nestin{sup +} stem cells, and the vast majority of cerebellar stem cells are quiescent. Data obtained by in vivo retrovirus injection indicate that stem cells do not produce neurons and astrocytes in adult mouse cerebellum. Instead, some cells labeled by retrovirus are Iba1{sup +} microglia. These results indicate that very few stem cells exist in adult mouse cerebellum, and none of these stem cells contribute to neurogenesis and astrogenesis under physiological condition.

  19. How do cells produce and regulate the driving force in the process of migration?

    Science.gov (United States)

    Zhong, Y.; Ji, B.

    2014-06-01

    Cell migration behaviors have been studied from various aspects and at different length scales (molecular, subcellular and cellular scales), however, the mechanisms of how cell produces and controls the driving force for its migration have not been fully understood. Here for the first time we draw a more unified picture of driving force production that integrates the mechanisms from molecular to subcellular and cellular levels to show how cell produces and regulates the driving force and thus control its motility. We suggest that although the external mechanical and chemical factors can influence cell migration, the cell is able to actively control and regulate its driving force for its motility through controlling the stability of cell adhesion via actively regulating its spreading shape. To demonstrate this picture of regulation of the driving force, a FEM-based simulation framework is developed by modeling the dynamics of adhesion at cell front, de-adhesion at cell rear, and forward motion of cell body under cell traction force for different cell shape. The migration of keratocyte and fibroblast cells is simulated for different matrix rigidity and rigidity gradient. We show that the cell migration speed biphasically depends on the matrix rigidity. The mechanism is that the variation of matrix rigidity tunes the balance of competition between stability of cell adhesion at cell front and instability of adhesion at cell rear, which consequently controls the driving force of cell migration. We further propose a parameter called motility factor for a quantitative description of impact of mechanical properties of matrix and cell shape on the driving force of cell migration.

  20. Virus-like particle of Macrobrachium rosenbergii nodavirus produced in Spodoptera frugiperda (Sf9) cells is distinctive from that produced in Escherichia coli.

    Science.gov (United States)

    Kueh, Chare Li; Yong, Chean Yeah; Masoomi Dezfooli, Seyedehsara; Bhassu, Subha; Tan, Soon Guan; Tan, Wen Siang

    2016-11-14

    Macrobrachium rosenbergii nodavirus (MrNV) is a virus native to giant freshwater prawn. Recombinant MrNV capsid protein has been produced in Escherichia coli, which self-assembled into virus-like particles (VLPs). However, this recombinant protein is unstable, degrading and forming heterogenous VLPs. In this study, MrNV capsid protein was produced in insect Spodoptera frugiperda (Sf9) cells through a baculovirus system. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the recombinant protein produced by the insect cells self-assembled into highly stable, homogenous VLPs each of approximately 40 nm in diameter. Enzyme-linked immunosorbent assay (ELISA) showed that the VLPs produced in Sf9 cells were highly antigenic and comparable to those produced in E. coli. In addition, the Sf9 produced VLPs were highly stable across a wide pH range (2-12). Interestingly, the Sf9 produced VLPs contained DNA of approximately 48 kilo base pairs and RNA molecules. This study is the first report on the production and characterization of MrNV VLPs produced in a eukaryotic system. The MrNV VLPs produced in Sf9 cells were about 10 nm bigger and had a uniform morphology compared with the VLPs produced in E. coli. The insect cell production system provides a good source of MrNV VLPs for structural and immunological studies as well as for host-pathogen interaction studies. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 2016.

  1. A Modified Method of Insulin Producing Cells’ Generation from Bone Marrow-Derived Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Paweł Czubak

    2014-01-01

    Full Text Available Type 1 diabetes mellitus is a result of autoimmune destruction of pancreatic insulin producing β-cells and so far it can be cured only by insulin injection, by pancreas transplantation, or by pancreatic islet cells’ transplantation. The methods are, however, imperfect and have a lot of disadvantages. Therefore new solutions are needed. The best one would be the use of differentiated mesenchymal stem cells (MSCs. In the present study, we investigated the potential of the bone marrow-derived MSCs line for in vitro differentiation into insulin producing cells (IPSs. We applied an 18-day protocol to differentiate MSCs. Differentiating cells formed cell clusters some of which resembled pancreatic islet-like cells. Using dithizone we confirmed the presence of insulin in the cells. What is more, the expression of proinsulin C-peptide in differentiated IPCs was analyzed by flow cytometry. For the first time, we investigated the influence of growth factors’ concentration on IPCs differentiation efficiency. We have found that an increase in the concentration of growth factors up to 60 ng/mL of β-FGF/EGF and 30 ng/mL of activin A/β-cellulin increases the percentage of IPCs. Further increase of growth factors does not show any increase of the percentage of differentiated cells. Our findings suggest that the presented protocol can be adapted for differentiation of insulin producing cells from stem cells.

  2. Interleukin 4-producing CD4+ T cells in the skin of cats with allergic dermatitis.

    Science.gov (United States)

    Roosje, P J; Dean, G A; Willemse, T; Rutten, V P M G; Thepen, T

    2002-03-01

    Lesional skin of cats with allergic dermatitis has a cellular infiltrate and a CD4/CD8 ratio comparable to that in humans with atopic dermatitis. CD4+ helper T cells and in particular cells belonging to the Th2 subset play an important role in disease pathogenesis in humans. We investigated the cytokine pattern of CD4+ T cells in situ, with special emphasis on the putative presence of cells producing interleukin 4 (IL4), in cats with allergic dermatitis. Immunohistochemical procedures were used to determine that CD4+ T cells in lesional and nonlesional skin of cats with allergic dermatitis can produce IL4, as occurs in humans. Lesional and nonlesional skin of cats with allergic dermatitis had significantly more IL4+ T cells (P = 0.001) than did skin of healthy control cats. Double staining indicated that all IL4+ cells were positive for pan-T or CD4 markers. Double labeling for mast cell chymase and IL4 stained primarily different cells. Western blotting demonstrated cross-reactivity between the antibody against human IL4 and a feline recombinant IL4. These results indicate that IL4 is primarily produced by CD4+ T cells and is also present in clinically uninvolved skin, indicating a role in the pathogenesis of allergic dermatitis in cats.

  3. Development of Microelectrode Arrays Using Electroless Plating for CMOS-Based Direct Counting of Bacterial and HeLa Cells.

    Science.gov (United States)

    Niitsu, Kiichi; Ota, Shoko; Gamo, Kohei; Kondo, Hiroki; Hori, Masaru; Nakazato, Kazuo

    2015-10-01

    The development of two new types of high-density, electroless plated microelectrode arrays for CMOS-based high-sensitivity direct bacteria and HeLa cell counting are presented. For emerging high-sensitivity direct pathogen counting, two technical challenges must be addressed. One is the formation of a bacteria-sized microelectrode, and the other is the development of a high-sensitivity and high-speed amperometry circuit. The requirement for microelectrode formation is that the gold microelectrodes are required to be as small as the target cell. By improving a self-aligned electroless plating technique, the dimensions of the microelectrodes on a CMOS sensor chip in this work were successfully reduced to 1.2 μm × 2.05 μm. This is 1/20th of the smallest size reported in the literature. Since a bacteria-sized microelectrode has a severe limitation on the current flow, the amperometry circuit has to have a high sensitivity and high speed with low noise. In this work, a current buffer was inserted to mitigate the potential fluctuation. Three test chips were fabricated using a 0.6- μm CMOS process: two with 1.2 μm × 2.05 μm (1024 × 1024 and 4 × 4) sensor arrays and one with 6- μm square (16 × 16) sensor arrays; and the microelectrodes were formed on them using electroless plating. The uniformity among the 1024 × 1024 electrodes arranged with a pitch of 3.6 μm × 4.45 μm was optically verified. For improving sensitivity, the trenches on each microelectrode were developed and verified optically and electrochemically for the first time. Higher sensitivity can be achieved by introducing a trench structure than by using a conventional microelectrode formed by contact photolithography. Cyclic voltammetry (CV) measurements obtained using the 1.2 μm × 2.05 μm 4 × 4 and 6- μm square 16 × 16 sensor array with electroless-plated microelectrodes successfully demonstrated direct counting of the bacteria-sized microbeads and HeLa cells.

  4. Expression of albumin and cytochrome P450 enzymes in HepG2 cells cultured with a nanotechnology-based culture plate with microfabricated scaffold.

    Science.gov (United States)

    Nakamura, Kazuaki; Kato, Natsuko; Aizawa, Kazuko; Mizutani, Reiko; Yamauchi, Junji; Tanoue, Akito

    2011-10-01

    The Nanoculture plate (NCP) is a recently developed plate which essentially consists of a textured surface with specific characteristics that induce spheroid formation: microfabrications with a micro-square pattern on the culture surface. The NCP can be used to generate uniform adhesive spheroids of cancer cell lines using conventional techniques without the need of any animal compounds. In this study, we assessed the performance of human hepatoma cell line HepG2 cells cultured with an NCP to evaluate the effects of the NCP on their hepatocyte-specific functions. The NCP facilitated the formation of three-dimensional (3D) HepG2 cell architecture. HepG2 cells cultured with an NCP exhibited enhanced mRNA expression levels of albumin and cytochrome P450 (CYP) enzymes compared to those cultured with a two-dimensional (2D) conventional plate. The expression levels of two specific liver-enriched transcription factors, hepatocyte nuclear factor 4α (HNF4α) and CCAAT/enhancer binding protein α (C/EBPα), were higher in HepG2 cells grown with the NCP than those in HepG2 cells grown with conventional plates before albumin and CYP enzymes expression levels were increased. The inducibility of CYP1A2 and CYP3A4 mRNA following exposure to inducers in HepG2 cells cultured with an NCP was comparable to that in HepG2 cells cultured with conventional plates, while the expression levels of CYP1A2 and CYP3A4 mRNA following exposure to inducers were higher when using an NCP than when using conventional plates. These results suggest that the use of an NCP enhances the hepatocyte-specific functions of HepG2 cells, such as drug-metabolizing enzyme expression, making the NCP/HepG2 system a useful tool for evaluating drug metabolism in vitro.

  5. Electroless Ni-Cu-P/nano-graphite composite coatings for bipolar plates of proton exchange membrane fuel cells

    Science.gov (United States)

    Lee, Cheng-Kuo

    2012-12-01

    This study evaluates the effects of an electroless Ni-Cu-P/nano-graphite composite coating on the surface characteristics of anodized 5083 aluminum alloy, including electrical resistivity, corrosion resistance of the alloy in a simulated solution of 0.5 M H2SO4 + 2 ppm NaF in polymer electrolyte membrane fuel cells (PEMFCs). The co-deposition and adhesion of the composite coatings on a 5083 substrate are enhanced by an anodizing process. The electroless Ni-Cu-P plating solution is prepared by adding different CuSO4·5H2O concentrations into the electroless Ni-P plating solution and adding nano-graphite (15-40 nm) particles to form the Ni-Cu-P/nano-graphite composite coatings. Experimental results indicate that the electroless Ni-Cu-P/nano-graphite composite coating enhances the hardness, conductivity, corrosion resistance of the 5083 substrate in the corrosive solution. The anodizing treatment enhances the electroless composite coatings by providing better uniformity, density, and adhesion compared to substrate without anodizing treatment. The electroless Ni-Cu-P/nano-graphite composite coating deposited on the optimal anodized 5083 substrate at a low CuSO4·5H2O concentration of 0.25 g l-1 with 20 g l-1 nano-graphite added have the best surface structure, highest hardness, electrical conductivity and corrosion resistance. Therefore, this novel electroless Ni-Cu-P/nano-graphite composite-coated 5083 aluminum alloy has potential applications in bipolar plates of PEM fuel cells.

  6. In situ cannulation, microgrid follow-up and low-density plating provide first passage endothelial cell masscultures for in vitro lining.

    Science.gov (United States)

    Zilla, P; Fasol, R; Dudeck, U; Siedler, S; Preiss, P; Fischlein, T; Müller-Glauser, W; Baitella, G; Sanan, D; Odell, J

    1990-08-01

    A rapid and reliable harvest and culture technique was developed to provide a sufficient number of autologous endothelial cells for the confluent in vitro lining of cardiovascular prostheses. Enzymatic endothelial cell detachment was achieved by the in situ application of collagenase to short vessel segments. This harvest technique resulted in a complete lack of contaminating smooth muscle cells in all of 124 cultures from nonhuman primates and 13 cultures from human adults. The use of a microgrid technique enabled the daily in situ quantification of available endothelial cells. To assess ideal plating densities after passage the population doubling time was continuously related to the cell density. Surprisingly, a low plating density of 1.5 X 10(3) endothelial cells/cm2 achieved 43% shorter cell cycles than the usual plating density of 1.0 X 10(4) endothelial cells/cm2. Moreover, low density plating enabled mass cultures after one single cell passage, thereby reducing the cell damaging effect of trypsin. When the growth characteristics of endothelial cells from five anatomically different vessel sites were compared, the external jugular vein--which would be easily accessible and dispensable in each patient--proved to be an excellent source for endothelial cell cultures. By applying in situ administration of collagenase, low density plating and microgrid follow-up to adult human saphenous vein endothelial cells, 14,000,000 first passage endothelial cells--sufficient for the in vitro lining of long vascular prostheses--were obtained 26.2 days after harvest. (95% confidence interval:22.3 to 32.2 days).

  7. Thymoproteasomes produce unique peptide motifs for positive selection of CD8(+) T cells.

    Science.gov (United States)

    Sasaki, Katsuhiro; Takada, Kensuke; Ohte, Yuki; Kondo, Hiroyuki; Sorimachi, Hiroyuki; Tanaka, Keiji; Takahama, Yousuke; Murata, Shigeo

    2015-01-01

    Positive selection in the thymus provides low-affinity T-cell receptor (TCR) engagement to support the development of potentially useful self-major histocompatibility complex class I (MHC-I)-restricted T cells. Optimal positive selection of CD8(+) T cells requires cortical thymic epithelial cells that express β5t-containing thymoproteasomes (tCPs). However, how tCPs govern positive selection is unclear. Here we show that the tCPs produce unique cleavage motifs in digested peptides and in MHC-I-associated peptides. Interestingly, MHC-I-associated peptides carrying these tCP-dependent motifs are enriched with low-affinity TCR ligands that efficiently induce the positive selection of functionally competent CD8(+) T cells in antigen-specific TCR-transgenic models. These results suggest that tCPs contribute to the positive selection of CD8(+) T cells by preferentially producing low-affinity TCR ligand peptides.

  8. Detection of PIVKA II produced by human hepatoma cells in nude mice.

    Science.gov (United States)

    Kohda, H; Ono, M; Sekiya, C; Ohta, H; Ohhira, M; Ohhira, M; Yoshida, Y; Ikeda, N; Namiki, M

    1991-03-01

    A novel experimental nude mouse model, which is useful for investigation of the mechanisms of PIVKA II synthesis, was established by inoculation with PIVKA II-producing human hepatoma cells (huH-1). We have found markedly elevated levels of PIVKA II in the plasma of nude mice transplanted with huH-1 cells and increased PIVKA II content in huH-1 tumor tissues. Whereas we have not found detectable level of PIVKA II neither in the plasma nor in tumor tissues of nude mice transplanted different human hepatoma cells (HLF) which is not producing PIVKA II. Histology of the tumor tissues produced by huH-1 cells revealed a thick trabecular pattern with blood spaces.

  9. Visualization and identification of IL-7 producing cells in reporter mice.

    Directory of Open Access Journals (Sweden)

    Renata I Mazzucchelli

    Full Text Available Interleukin-7 (IL-7 is required for lymphocyte development and homeostasis although the actual sites of IL-7 production have never been clearly identified. We produced a bacterial artificial chromosome (BAC transgenic mouse expressing ECFP in the Il7 locus. The construct lacked a signal peptide and ECFP (enhanced cyan fluorescent protein accumulated inside IL-7-producing stromal cells in thoracic thymus, cervical thymus and bone marrow. In thymus, an extensive reticular network of IL-7-containing processes extended from cortical and medullary epithelial cells, closely contacting thymocytes. Central memory CD8 T cells, which require IL-7 and home to bone marrow, physically associated with IL-7-producing cells as we demonstrate by intravital imaging.

  10. Confocal microscopy of colloidal dispersions in shear flow using a counter-rotating cone-plate shear cell

    Energy Technology Data Exchange (ETDEWEB)

    Derks, Didi; Wisman, Hans; Blaaderen, Alfons van; Imhof, Arnout [Soft Condensed Matter, Debye Institute, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The (Netherlands)

    2004-09-29

    We report on novel possibilities for studying colloidal suspensions in a steady shear field in real space. Fluorescence confocal microscopy is combined with the use of a counter-rotating cone-plate shear cell. This allows imaging of individual particles in the bulk of a sheared suspension in a stationary plane. Moreover, this plane of zero velocity can be moved in the velocity gradient direction while keeping the shear rate constant. The colloidal system under study consists of rhodamine labelled PMMA spheres in a nearly density and refractive index matched mixture of cyclohexylbromide and cis-decalin. We show measured flow profiles in both the fluid and the crystalline phase and find indications for shear banding in the case of a sheared crystal. Furthermore, we show that, thanks to the counter-rotating principle of the cone-plate shear cell, a layer of particles in the bulk of a sheared crystalline suspension can be imaged for a prolonged time, with the result that their positions can be tracked.

  11. Characterization of thermal and mechanical properties of polypropylene-based composites for fuel cell bipolar plates and development of educational tools in hydrogen and fuel cell technologies

    Science.gov (United States)

    Lopez Gaxiola, Daniel

    In this project we developed conductive thermoplastic resins by adding varying amounts of three different carbon fillers: carbon black (CB), synthetic graphite (SG) and multi-walled carbon nanotubes (CNT) to a polypropylene matrix for application as fuel cell bipolar plates. This component of fuel cells provides mechanical support to the stack, circulates the gases that participate in the electrochemical reaction within the fuel cell and allows for removal of the excess heat from the system. The materials fabricated in this work were tested to determine their mechanical and thermal properties. These materials were produced by adding varying amounts of single carbon fillers to a polypropylene matrix (2.5 to 15 wt.% Ketjenblack EC-600 JD carbon black, 10 to 80 wt.% Asbury Carbons' Thermocarb TC-300 synthetic graphite, and 2.5 to 15 wt.% of Hyperion Catalysis International's FIBRIL(TM) multi-walled carbon nanotubes) In addition, composite materials containing combinations of these three fillers were produced. The thermal conductivity results showed an increase in both through-plane and in-plane thermal conductivities, with the largest increase observed for synthetic graphite. The Department of Energy (DOE) had previously set a thermal conductivity goal of 20 W/m·K, which was surpassed by formulations containing 75 wt.% and 80 wt.% SG, yielding in-plane thermal conductivity values of 24.4 W/m·K and 33.6 W/m·K, respectively. In addition, composites containing 2.5 wt.% CB, 65 wt.% SG, and 6 wt.% CNT in PP had an in-plane thermal conductivity of 37 W/m·K. Flexural and tensile tests were conducted. All composite formulations exceeded the flexural strength target of 25 MPa set by DOE. The tensile and flexural modulus of the composites increased with higher concentration of carbon fillers. Carbon black and synthetic graphite caused a decrease in the tensile and flexural strengths of the composites. However, carbon nanotubes increased the composite tensile and flexural

  12. Staphylococcus aureus produces membrane-derived vesicles that induce host cell death.

    Directory of Open Access Journals (Sweden)

    Mamata Gurung

    Full Text Available Gram-negative bacteria produce outer membrane vesicles that play a role in the delivery of virulence factors to host cells. However, little is known about the membrane-derived vesicles (MVs produced by gram-positive bacteria. The present study examined the production of MVs from Staphylococcus aureus and investigated the delivery of MVs to host cells and subsequent cytotoxicity. Four S. aureus strains tested, two type strains and two clinical isolates, produced spherical nanovesicles during in vitro culture. MVs were also produced during in vivo infection of a clinical S. aureus isolate in a mouse pneumonia model. Proteomic analysis showed that 143 different proteins were identified in the S. aureus-derived MVs. S. aureus MVs were interacted with the plasma membrane of host cells via a cholesterol-rich membrane microdomain and then delivered their component protein A to host cells within 30 min. Intact S. aureus MVs induced apoptosis of HEp-2 cells in a dose-dependent manner, whereas lysed MVs neither delivered their component into the cytosol of host cells nor induced cytotoxicity. In conclusion, this study is the first report that S. aureus MVs are an important vehicle for delivery of bacterial effector molecules to host cells.

  13. Strain Library Imaging Protocol for high-throughput, automated single-cell microscopy of large bacterial collections arrayed on multiwell plates.

    Science.gov (United States)

    Shi, Handuo; Colavin, Alexandre; Lee, Timothy K; Huang, Kerwyn Casey

    2017-02-01

    Single-cell microscopy is a powerful tool for studying gene functions using strain libraries, but it suffers from throughput limitations. Here we describe the Strain Library Imaging Protocol (SLIP), which is a high-throughput, automated microscopy workflow for large strain collections that requires minimal user involvement. SLIP involves transferring arrayed bacterial cultures from multiwell plates onto large agar pads using inexpensive replicator pins and automatically imaging the resulting single cells. The acquired images are subsequently reviewed and analyzed by custom MATLAB scripts that segment single-cell contours and extract quantitative metrics. SLIP yields rich data sets on cell morphology and gene expression that illustrate the function of certain genes and the connections among strains in a library. For a library arrayed on 96-well plates, image acquisition can be completed within 4 min per plate.

  14. Vitamin A Impairs the Reprogramming of Tregs into IL-17-Producing Cells during Intestinal Inflammation

    Science.gov (United States)

    Tejón, Gabriela; Manríquez, Valeria; De Calisto, Jaime; Flores-Santibáñez, Felipe; Hidalgo, Yessia; Crisóstomo, Natalia; Fernández, Dominique; Sauma, Daniela; Mora, J. Rodrigo; Bono, María R.; Rosemblatt, Mario

    2015-01-01

    Maintaining the identity of Foxp3+ regulatory T cells (Tregs) is critical for controlling immune responses in the gut, where an imbalance between Tregs and T effector cells has been linked to inflammatory bowel disease. Accumulating evidence suggests that Tregs can convert into Th17 cells and acquire an inflammatory phenotype. In this study, we used an adoptive transfer model of Ag-specific T cells to study the contribution of different factors to the reprogramming of in vitro-generated Treg cells (iTreg) into IL-17-producing cells in a mouse model of gut inflammation in vivo. Our results show that intestinal inflammation induces the reprogramming of iTreg cells into IL-17-producing cells and that vitamin A restrains reprogramming in the gut. We also demonstrate that the presence of IL-2 during the in vitro generation of iTreg cells confers resistance to Th17 conversion but that IL-2 and retinoic acid (RA) cooperate to maintain Foxp3 expression following stimulation under Th17-polarizing conditions. Additionally, although IL-2 and RA differentially regulate the expression of different Treg cell suppressive markers, Treg cells generated under different polarizing conditions present similar suppressive capacity. PMID:26583087

  15. Structure and properties of Mo-containing diamond-like carbon films produced by ion source assisted cathodic arc ion-plating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L.L. [Key Laboratory of Artificial Micro- and Nano-Materials of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 China (China); Wang, R.Y. [School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072 (China); Yan, S.J.; Zhang, R. [Key Laboratory of Artificial Micro- and Nano-Materials of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 China (China); Yang, B. [School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072 (China); Zhang, Z.D.; Huang, Z.H. [Key Laboratory of Artificial Micro- and Nano-Materials of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 China (China); Fu, D.J., E-mail: djfu@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-Materials of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 China (China)

    2013-12-01

    Ion source assisted cathodic arc ion-plating was used to synthesize molybdenum containing diamond-like carbon films. The element of molybdenum is uniformly distributed in our sample as analyzed by Rutherford backscattering spectroscopy. The surface morphology of the films was analyzed by scanning electron microscope and atomic force microscope. The structure and bond state of the molybdenum containing diamond-like carbon films were characterized by X-ray diffraction, high resolution transmission electron microscopy, Raman spectra, and X-ray photoelectron spectroscopy. The Mo content in the films was controlled by varying of the acetylene gas flow rates. The root-mean square roughness of the as-deposited sample was found in the range of 1.5 nm. The hardness of 35 GPa has been achieved at the optimum conditions of synthesis. This can be attributed to formation multilayer structure during deposition process and the formation of hard molybdenum carbide phase with C=Mo bonding. The results show that ion source assisted cathodic arc ion-plating is an effective technique to fabricate metal-containing carbon films with controlled metal contents.

  16. Liver dendritic cells present bacterial antigens and produce cytokines upon Salmonella encounter.

    Science.gov (United States)

    Johansson, Cecilia; Wick, Mary Jo

    2004-02-15

    The capacity of murine liver dendritic cells (DC) to present bacterial Ags and produce cytokines after encounter with Salmonella was studied. Freshly isolated, nonparenchymal liver CD11c(+) cells had heterogeneous expression of MHC class II and CD11b and a low level of CD40 and CD86 expression. Characterization of liver DC subsets revealed that CD8alpha(-)CD4(-) double negative cells constituted the majority of liver CD11c(+) ( approximately 85%) with few cells expressing CD8alpha or CD4. Flow cytometry analysis of freshly isolated CD11c(+) cells enriched from the liver and cocultured with Salmonella expressing green fluorescent protein (GFP) showed that CD11c(+) MHC class II(high) cells had a greater capacity to internalize Salmonella relative to CD11c(+) MHC class II(low) cells. Moreover, both CD8alpha(-) and CD8alpha(+) liver DC internalized bacteria with similar efficiency after both in vitro and in vivo infection. CD11c(+) cells enriched from the liver could also process Salmonella for peptide presentation on MHC class I and class II to primary, Ag-specific T cells after internalization requiring actin cytoskeletal rearrangements. Flow cytometry analysis of liver CD11c(+) cells infected with Salmonella expressing GFP showed that both CD8alpha(-) and CD8alpha(+) DC produced IL-12p40 and TNF-alpha. The majority of cytokine-positive cells did not contain bacteria (GFP(-)) whereas only a minor fraction of cytokine-positive cells were GFP(+). Furthermore, only approximately 30-50% of liver DC containing bacteria (GFP(+)) produced cytokines. Thus, liver DC can internalize and process Salmonella for peptide presentation to CD4(+) and CD8(+) T cells and elicit proinflammatory cytokine production upon Salmonella encounter, suggesting that DC in the liver may contribute to immunity against hepatotropic bacteria.

  17. Interleukin 17-producing γδT cells promote hepatic regeneration in mice.

    Science.gov (United States)

    Rao, Raghavendra; Graffeo, Christopher S; Gulati, Rishabh; Jamal, Mohsin; Narayan, Suchithra; Zambirinis, Constantinos P; Barilla, Rocky; Deutsch, Michael; Greco, Stephanie H; Ochi, Atsuo; Tomkötter, Lena; Blobstein, Reuven; Avanzi, Antonina; Tippens, Daniel M; Gelbstein, Yisroel; Van Heerden, Eliza; Miller, George

    2014-08-01

    Subsets of leukocytes synergize with regenerative growth factors to promote hepatic regeneration. γδT cells are early responders to inflammation-induced injury in a number of contexts. We investigated the role of γδT cells in hepatic regeneration using mice with disruptions in Tcrd (encodes the T-cell receptor δ chain) and Clec7a (encodes C-type lectin domain family 7 member a, also known as DECTIN1). We performed partial hepatectomies on wild-type C57BL/6, CD45.1, Tcrd(-/-), or Clec7a(-/-) mice. Cells were isolated from livers of patients and mice via mechanical and enzymatic digestion. γδT cells were purified by fluorescence-activated cell sorting. In mice, partial hepatectomy up-regulated expression of CCL20 and ligands of Dectin-1, which was associated with recruitment and activation of γδT cells and their increased production of interleukin (IL)-17 family cytokines. Recruited γδT cells induced production of IL-6 by antigen-presenting cells and suppressed expression of interferon gamma by natural killer T cells, promoting hepatocyte proliferation. Absence of IL-17-producing γδT cells or deletion of Dectin-1 prevented development of regenerative phenotypes in subsets of innate immune cells. This slowed liver regeneration and was associated with reduced expression of regenerative growth factors and cell cycle regulators. Conversely, exogenous administration of IL-17 family cytokines or Dectin-1 ligands promoted regeneration. More broadly, we found that γδT cells are required for inflammatory responses mediated by IL-17 and Dectin-1. γδT cells regulate hepatic regeneration by producing IL-22 and IL-17, which have direct mitogenic effects on hepatocytes and promote a regenerative phenotype in hepatic leukocytes, respectively. Dectin-1 ligation is required for γδT cells to promote hepatic regeneration. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

  18. Retinoic acid primes human dendritic cells to induce gut-homing, IL-10-producing regulatory T cells

    NARCIS (Netherlands)

    Bakdash, G.; Vogelpoel, L.T.; Capel, T.M. van; Kapsenberg, M.L.; Jong, E.C. de

    2015-01-01

    The vitamin A metabolite all-trans retinoic acid (RA) is an important determinant of intestinal immunity. RA primes dendritic cells (DCs) to express CD103 and produce RA themselves, which induces the gut-homing receptors alpha4beta7 and CCR9 on T cells and amplifies transforming growth factor (TGF)-

  19. Fractal multifiber microchannel plates

    Science.gov (United States)

    Cook, Lee M.; Feller, W. B.; Kenter, Almus T.; Chappell, Jon H.

    1992-01-01

    The construction and performance of microchannel plates (MCPs) made using fractal tiling mehtods are reviewed. MCPs with 40 mm active areas having near-perfect channel ordering were produced. These plates demonstrated electrical performance characteristics equivalent to conventionally constructed MCPs. These apparently are the first MCPs which have a sufficiently high degree of order to permit single channel addressability. Potential applications for these devices and the prospects for further development are discussed.

  20. Fusion of proinsulin-producing bone marrow-derived cells with hepatocytes in diabetes.

    Science.gov (United States)

    Fujimiya, Mineko; Kojima, Hideto; Ichinose, Masumi; Arai, Ryohachi; Kimura, Hiroshi; Kashiwagi, Atsunori; Chan, Lawrence

    2007-03-06

    We previously reported that diabetes in mice is associated with the appearance of proinsulin-producing (Proins-P) cells in the liver. It was unclear, however, whether these Proins-P bone marrow-derived cells (BMDC) merely transit through the liver or undergo fusion with hepatocytes, normally an extremely rare event. In this study, we found that, in diabetes, BMDC in the liver produce not only Proins but also TNF-alpha, suggesting that diabetes reprograms gene expression in BMDC, turning on "inappropriate" genes. Bone marrow transplantation using genetically marked donor and recipient mice showed that fusion occurs between Proins-P BMDC and hepatocytes. Cell fusion is further supported by the presence of the Y chromosome in Proins-P cells in female mice that received male bone marrow transplantation cells. Morphologically, Proins-P fusion cells are albumin-producing hepatocytes that constitute approximately 2.5% of the liver section area 5 months after diabetes induction. An extensive search failed to reveal any fusion cells in nondiabetic mice. Thus, diabetes causes fusion between Proins-P BMDC and hepatocytes in vivo, an observation that has implications for the pathophysiology of diabetes as well as the fundamental biology of heterotypic cell fusion.

  1. From the regulatory functions of B cells to the identification of cytokine-producing plasma cell subsets.

    Science.gov (United States)

    Dang, Van Duc; Hilgenberg, Ellen; Ries, Stefanie; Shen, Ping; Fillatreau, Simon

    2014-06-01

    B lymphocytes have a unique role as antibody-producing cells. Antibodies are key mediators of humoral immunity against infections, and are thought to account for the protection afforded by successful vaccines. B cells can also secrete cytokines and subsequently regulate immune responses mediated by T and innate cells. Remarkably, recent studies identified plasma blasts/plasma cells as the main types of activated B cells producing the cytokines interleukin (IL)-10, IL-35, tumor necrosis factor (TNF)-α, IL-17, and GM-CSF in various contexts in mice. Here, we discuss these observations, which suggest the existence of various subsets of plasma blast/plasma cells distinguishable through their cytokine expression pattern.

  2. Distribution of slow-cycling cells in epiphyseal cartilage and requirement of β-catenin signaling for their maintenance in growth plate.

    Science.gov (United States)

    Candela, Maria Elena; Cantley, Leslie; Yasuaha, Rika; Iwamoto, Masahiro; Pacifici, Maurizio; Enomoto-Iwamoto, Motomi

    2014-05-01

    Slow proliferation is one of the characteristics of stem cells. We examined the presence, distribution, and regulation of slow-cycling cells in the developing and growing skeleton using a pulse-chase method with a new nucleoside derivative, 5-ethynyl-2'-deoxyuridine (EdU). C57BL/6 mice received daily intraperitoneal injections of EdU from postnatal day 4 to day 7. One day after the last EdU injection, a large population of cells in articular cartilage and growth plate was labeled. Six weeks after the last injection, the number of EdU-labeled cells dramatically decreased, but a small number of them were dominantly present in the articular surface, and the labeling index was significantly higher in the surface than that in the rest of articular cartilage. In the growth plate, most EdU-positive cells were found in the top layer that lies immediately below the secondary ossification center. Interestingly, postnatal conditional ablation of β-catenin in cartilage caused a complete loss of the EdU-labeled cells in growth plate that displayed disorganization and dysfunction. Together, our data demonstrate that slow-cycling cells do reside in specific locations and numbers in both articular cartilage and growth plate. The β-catenin signaling pathway appears to play a previously unsuspected role in maintenance of the slow-cycling cells.

  3. Programmed cell death in barley aleurone cells is not directly stimulated by reactive oxygen species produced in response to gibberellin.

    Science.gov (United States)

    Aoki, Nozomi; Ishibashi, Yushi; Kai, Kyohei; Tomokiyo, Reisa; Yuasa, Takashi; Iwaya-Inoue, Mari

    2014-05-01

    The cereal aleurone layer is a secretory tissue that produces enzymes to hydrolyze the starchy endosperm during germination. We recently demonstrated that reactive oxygen species (ROS), produced in response to gibberellins (GA), promoted GAMyb expression, which induces α-amylase expression in barley aleurone cells. On the other hand, ROS levels increase during programmed cell death (PCD) in barley aleurone cells, and GAMyb is involved in PCD of these cells. In this study, we investigated whether the ROS produced in response to GA regulate PCD directly by using mutants of Slender1 (SLN1), a DELLA protein that negatively regulates GA signaling. The wild-type, the sln1c mutant (which exhibits gibberellin-type signaling even in the absence of GA), and the Sln1d mutant (which is gibberellin-insensitive with respect to α-amylase production) all produced ROS in response to GA, suggesting that ROS production in aleurone cells in response to GA is independent of GA signaling through this DELLA protein. Exogenous GA promoted PCD in the wild-type. PCD in sln1c was induced even without exogenous GA (and so without induction of ROS), whereas PCD in Sln1d was not induced in the presence of exogenous GA, even though the ROS content increased significantly in response to GA. These results suggest that PCD in barley aleurone cells is not directly stimulated by ROS produced in response to GA but is regulated by GA signaling through DELLA protein.

  4. Reversal of hyperglycemia in mice by using human expandable insulin-producing cells differentiated from fetal liver progenitor cells

    Science.gov (United States)

    Zalzman, Michal; Gupta, Sanjeev; Giri, Ranjit K.; Berkovich, Irina; Sappal, Baljit S.; Karnieli, Ohad; Zern, Mark A.; Fleischer, Norman; Efrat, Shimon

    2003-06-01

    Beta-cell replacement is considered to be the most promising approach for treatment of type 1 diabetes. Its application on a large scale is hindered by a shortage of cells for transplantation. Activation of insulin expression, storage, and regulated secretion in stem/progenitor cells offers novel ways to overcome this shortage. We explored whether fetal human progenitor liver cells (FH) could be induced to differentiate into insulin-producing cells after expression of the pancreatic duodenal homeobox 1 (Pdx1) gene, which is a key regulator of pancreatic development and insulin expression in beta cells. FH cells possess a considerable replication capacity, and this was further extended by introduction of the gene for the catalytic subunit of human telomerase. Immortalized FH cells expressing Pdx1 activated multiple beta-cell genes, produced and stored considerable amounts of insulin, and released insulin in a regulated manner in response to glucose. When transplanted into hyperglycemic immunodeficient mice, the cells restored and maintained euglycemia for prolonged periods. Quantitation of human C-peptide in the mouse serum confirmed that the glycemia was normalized by the transplanted human cells. This approach offers the potential of a novel source of cells for transplantation into patients with type 1 diabetes.

  5. In vitro cultivation of human fetal pancreatic ductal stem cells and their differentiation into insulin-producing cells

    Institute of Scientific and Technical Information of China (English)

    Zhong-Xiang Yao; Mao-Lin Qin; Jian-Jun Liu; Xing-Shu Chen; De-Shan Zhou

    2004-01-01

    AIM: To isolate, culture and identify the human fetal pancreatic ductal stem cells in vitro, and to observe the potency of these multipotential cells differentiation into insulin-producing cells.METHODS: The human fetal pancreas was digested by 1 g/L collagease type Ⅳ and then 2.5 g/L trypsin was used to isolate the pancreatic ducta stem cells, followed by culture in serum-free, glucose-free DMEM media with some additional chemical substrates in vitro (according to the different Stage). The cells were induced by glucose-free (control),5 mmol/L, 17.8 mmol/L and 25 mmol/L glucose, respectively.The cell types of differentiated cells were identified using immunocytochemical staining.RESULTS: The shape of human fetal pancreatic ductal stem cells culturedin vitro was firstly fusiform in the first 2 wk,and became monolayer and cobblestone pattern after another 3 to 4 wk. After induced and differentiated by the glucose of different concentrations for another 1 to 2 wk,the cells formed the pancreatic islet-like structures. The identification and potency of these cells were then identified by using the pancreatic ductal stem cell marker, cytokeratin-19 (CK-19), pancreatic β cell marker, insulin and pancreatic α cell marker, glucagons with immunocytochemical staining.At the end of the second week, 95.2% of the cells were positive for CK-19 immunoreactivity. Up to 22.7% of the cells induced by glucose were positive for insulin immunoreactivity, and less than 3.8% of the cells were positive for glucagon immunoreactivity in pancreatic isletlike structures. The positive ratio of immunoreactive staining was dependent on the concentration of glucose, and it was observed that the 17.8 mmol/L glucose stimulated effectively to produce insulin- and glucagons-producing cells.CONCLUSION: The human fetal pancreatic ductal stem cells are capable of proliferation in vitro. These cells have multidifferentiation potential and can be induced by glucose and differentiated into insulin-producing

  6. Generation of a Chinese Hamster Ovary Cell Line Producing Recombinant Human Glucocerebrosidase

    Directory of Open Access Journals (Sweden)

    Juliana Branco Novo

    2012-01-01

    Full Text Available Impaired activity of the lysosomal enzyme glucocerebrosidase (GCR results in the inherited metabolic disorder known as Gaucher disease. Current treatment consists of enzyme replacement therapy by administration of exogenous GCR. Although effective, it is exceptionally expensive, and patients worldwide have a limited access to this medicine. In Brazil, the public healthcare system provides the drug free of charge for all Gaucher’s patients, which reaches the order of $ 84 million per year. However, the production of GCR by public institutions in Brazil would reduce significantly the therapy costs. Here, we describe a robust protocol for the generation of a cell line producing recombinant human GCR. The protein was expressed in CHO-DXB11 (dhfr− cells after stable transfection and gene amplification with methotrexate. As expected, glycosylated GCR was detected by immunoblotting assay both as cell-associated (~64 and 59 kDa and secreted (63–69 kDa form. Analysis of subclones allowed the selection of stable CHO cells producing a secreted functional enzyme, with a calculated productivity of 5.14 pg/cell/day for the highest producer. Although being laborious, traditional methods of screening high-producing recombinant cells may represent a valuable alternative to generate expensive biopharmaceuticals in countries with limited resources.

  7. Generation of a Chinese Hamster Ovary Cell Line Producing Recombinant Human Glucocerebrosidase

    Science.gov (United States)

    Novo, Juliana Branco; Morganti, Ligia; Moro, Ana Maria; Paes Leme, Adriana Franco; Serrano, Solange Maria de Toledo; Raw, Isaias; Ho, Paulo Lee

    2012-01-01

    Impaired activity of the lysosomal enzyme glucocerebrosidase (GCR) results in the inherited metabolic disorder known as Gaucher disease. Current treatment consists of enzyme replacement therapy by administration of exogenous GCR. Although effective, it is exceptionally expensive, and patients worldwide have a limited access to this medicine. In Brazil, the public healthcare system provides the drug free of charge for all Gaucher's patients, which reaches the order of $ 84 million per year. However, the production of GCR by public institutions in Brazil would reduce significantly the therapy costs. Here, we describe a robust protocol for the generation of a cell line producing recombinant human GCR. The protein was expressed in CHO-DXB11 (dhfr−) cells after stable transfection and gene amplification with methotrexate. As expected, glycosylated GCR was detected by immunoblotting assay both as cell-associated (~64 and 59 kDa) and secreted (63–69 kDa) form. Analysis of subclones allowed the selection of stable CHO cells producing a secreted functional enzyme, with a calculated productivity of 5.14 pg/cell/day for the highest producer. Although being laborious, traditional methods of screening high-producing recombinant cells may represent a valuable alternative to generate expensive biopharmaceuticals in countries with limited resources. PMID:23091360

  8. B cells produce less IL-10, IL-6 and TNF-α in myasthenia gravis.

    Science.gov (United States)

    Yilmaz, Vuslat; Oflazer, Piraye; Aysal, Fikret; Parman, Yeşim G; Direskeneli, Haner; Deymeer, Feza; Saruhan-Direskeneli, Güher

    2015-06-01

    B cells from myasthenia gravis (MG) patients with autoantibodies (Aab) against acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or with no detectable Aab were investigated as cytokine producing cells in this study. B cells were evaluated for memory phenotypes and expressions of IL-10, IL-6 and IL-12A. Induced productions of IL-10, IL-6, IL-12p40, TNF-α and LT from isolated B cells in vitro were measured by immunoassays. MG patients receiving immunosuppressive treatment had higher proportions of memory B cells compared with healthy controls and untreated patients. With CD40 stimulation MG patients produced significantly lower levels of IL-10, IL-6. With CD40 and B cell receptor stimulation of B cells, TNF-α production also decreased in addition to these cytokines. The lower levels of these cytokine productions were not related to treatment. Our results confirm a disturbance of B cell subpopulations in MG subgroups on immunosuppressive treatment. B cell derived IL-10, IL-6 and TNF-α are down-regulated in MG, irrespective of different antibody productions. Ineffective cytokine production by B cells may be a susceptibility factor in dysregulation of autoimmune Aab production.

  9. Conventional NK cells can produce IL-22 and promote host defense in Klebsiella pneumoniae pneumonia.

    Science.gov (United States)

    Xu, Xin; Weiss, Ido D; Zhang, Hongwei H; Singh, Satya P; Wynn, Thomas A; Wilson, Mark S; Farber, Joshua M

    2014-02-15

    It was reported that host defense against pulmonary Klebsiella pneumoniae infection requires IL-22, which was proposed to be of T cell origin. Supporting a role for IL-22, we found that Il22(-/-) mice had decreased survival compared with wild-type mice after intratracheal infection with K. pneumoniae. Surprisingly, however, Rag2(-/-) mice did not differ from wild-type mice in survival or levels of IL-22 in the lungs postinfection with K. pneumoniae. In contrast, K. pneumoniae-infected Rag2(-/-)Il2rg(-/-) mice failed to produce IL-22. These data suggested a possible role for NK cells or other innate lymphoid cells in host defense and production of IL-22. Unlike NK cell-like innate lymphoid cells that produce IL-22 and display a surface phenotype of NK1.1(-)NKp46(+)CCR6(+), lung NK cells showed the conventional phenotype, NK1.1(+)NKp46(+)CCR6(-). Mice depleted of NK cells using anti-asialo GM1 showed decreased survival and higher lung bacterial counts, as well as increased dissemination of K. pneumoniae to blood and liver, compared with control-treated mice. NK cell depletion also led to decreased production of IL-22 in the lung. Within 1 d postinfection, although there was no increase in the number of lung NK cells, a subset of lung NK cells became competent to produce IL-22, and such cells were found in both wild-type and Rag2(-/-) mice. Our data suggest that, during pulmonary infection of mice with K. pneumoniae, conventional NK cells are required for optimal host defense, which includes the production of IL-22.

  10. In vitro cell cultures obtained from different explants of Corylus avellana produce Taxol and taxanes

    Directory of Open Access Journals (Sweden)

    Cavalli Francesca

    2006-12-01

    Full Text Available Abstract Background Taxol is an effective antineoplastic agent, originally extracted from the bark of Taxus brevifolia with a low yield. Many attempts have been made to produce Taxol by chemical synthesis, semi-synthesis and plant tissue cultures. However, to date, the availability of this compound is not sufficient to satisfy the commercial requirements. The aim of the present work was to produce suspension cell cultures from plants not belonging to Taxus genus and to verify whether they produced Taxol and taxanes. For this purpose different explants of hazel (Corylus avellana species were used to optimize the protocol for inducing in vitro callus, an undifferentiated tissue from which suspension cell cultures were established. Results Calli were successfully induced from stems, leaves and seeds grown in various hormone concentrations and combinations. The most suitable callus to establish suspension cell cultures was obtained from seeds. Media recovered from suspension cell cultures contained taxanes, and showed antiproliferative activity on human tumour cells. Taxol, 10-deacetyltaxol and 10-deacetylbaccatin III were the main taxanes identified. The level of Taxol recovered from the media of hazel cultures was similar to that found in yew cultures. Moreover, the production of taxanes in hazel cell cultures increased when elicitors were used. Conclusion Here we show that hazel cell cultures produce Taxol and taxanes under controlled conditions. This result suggests that hazel possesses the enzymes for Taxol production, which until now was considered to be a pathway particular to Taxus genus. The main benefit of producing taxanes through hazel cell cultures is that hazel is widely available, grows at a much faster rate in vivo, and is easier to cultivate in vitro than yew. In addition, the production of callus directly from hazel seeds shortens the culture time and minimizes the probability of contamination. Therefore, hazel could become a

  11. Rapid screening of purification strategies for the capture of a human recombinant F(ab')2 expressed in baculovirus-infected cells using a micro-plate approach and SELDI-MS.

    Science.gov (United States)

    Pezzini, J; Brenac Brochier, V; Barrouillet, M P; Cerruti, M; Clofent-Sanchez, G; Schapman, A; Topol, A; Robert, R; Cabanne, C; Cerruti, P; Santarelli, X

    2009-08-15

    The development of a capture step of a human recombinant F(ab')(2) produced and expressed in baculovirus-infected cells was investigated by screening three mixed-mode chromatography sorbents (HEA HyperCel, PPA HyperCel and MEP HyperCel) and two ion exchangers (Q Ceramic HyperD F, S Ceramic HyperD F) sorbents using a 96-well plate format and SELDI-MS. HEA HyperCel gave the best separation performance therefore the conditions tested in micro-plate were transferred to laboratory scale chromatographic experiments, confirming that the recombinant F(ab')(2) was effectively captured on the mixed-mode sorbent without any pre-treatment of the crude extract with a 82% recovery and a 39-fold purification.

  12. A review of composite and metallic bipolar plates in proton exchange membrane fuel cell: Materials, fabrication, and material selection

    Science.gov (United States)

    Taherian, Reza

    2014-11-01

    Proton exchange membrane (PEM) fuel cells offer exceptional potential for a clean, efficient, and reliable power source. The bipolar plate (BP) is a key component in this device, as it connects each cell electrically, supplies reactant gases to both anode and cathode, and removes reaction products from the cell. BPs have primarily been fabricated from high-density graphite, but in recent years, much attention has been paid to develop the cost-effective and feasible alternative materials. Recently, two different classes of materials have been attracted attention: metals and composite materials. This paper offers a comprehensive review of the current researches being carried out on the metallic and composite BPs, covering materials and fabrication methods. In this research, the phenomenon of ionic contamination due to the release of the corrosion products of metallic BP and relative impact on the durability as well as performance of PEM fuel cells is extensively investigated. Furthermore, in this paper, upon several effective parameters on commercialization of PEM fuel cells, such as stack cost, weight, volume, durability, strength, ohmic resistance, and ionic contamination, a material selection is performed among the most common BPs currently being used. This material selection is conducted by using Simple Additive Weighting Method (SAWM).

  13. Host cell capable of producing enzymes useful for degradation of lignocellulosic material

    Science.gov (United States)

    Los, Alrik Pieter; Sagt, Cornelis Maria Jacobus; Schooneveld-Bergmans, Margot Elisabeth Francoise; Damveld, Robbertus Antonius

    2015-08-18

    The invention relates to a host cell comprising at least four different heterologous polynucleotides chosen from the group of polynucleotides encoding cellulases, hemicellulases and pectinases, wherein the host cell is capable of producing the at least four different enzymes chosen from the group of cellulases, hemicellulases and pectinases, wherein the host cell is a filamentous fungus and is capable of secretion of the at least four different enzymes. This host cell can suitably be used for the production of an enzyme composition that can be used in a process for the saccharification of cellulosic material.

  14. Host cell capable of producing enzymes useful for degradation of lignocellulosic material

    Energy Technology Data Exchange (ETDEWEB)

    Los, Alrik Pieter; Sagt, Cornelis Maria Jacobus; Schoonneveld-Bergmans, Margot Elisabeth Francoise; Damveld, Robbertus Antonius

    2017-08-22

    The invention relates to a host cell comprising at least four different heterologous polynucleotides chosen from the group of polynucleotides encoding cellulases, hemicellulases and pectinases, wherein the host cell is capable of producing the at least four different enzymes chosen from the group of cellulases, hemicellulases and pectinases, wherein the host cell is a filamentous fungus and is capable of secretion of the at least four different enzymes. This host cell can suitably be used for the production of an enzyme composition that can be used in a process for the saccharification of cellulosic material.

  15. A cell sorting protocol for selecting high-producing sub-populations of Sf9 and High Five™ cells.

    Science.gov (United States)

    Vidigal, João; Dias, Mafalda M; Fernandes, Fabiana; Patrone, Marco; Bispo, Cláudia; Andrade, Cláudia; Gardner, Rui; Carrondo, Manuel J T; Alves, Paula M; Teixeira, Ana P

    2013-12-01

    Insect cell lines such as Sf9 and High Five™ have been widely used to produce recombinant proteins mostly by the lytic baculovirus vector system. We have recently established an expression platform in Sf9 cells using a fluorescence-based recombinase mediated cassette exchange (RMCE) strategy which has similar development timelines but avoids baculovirus infection. To expedite cell engineering efforts, a robust fluorescence-activated cell sorting (FACS) protocol optimized for insect cells was developed here. The standard sorting conditions used for mammalian cells proved to be unsuitable, resulting in post-sorting viabilities below 10% for both cell lines. We found that the extreme sensitivity to the shear stress displayed by Sf9 and High Five™ cells was the limiting factor, and using Pluronic F-68 in the cell suspension could increase post-sorting viabilities in a dose dependent manner. The newly developed protocol was then used to sort stable populations of both cell lines tagged with a DsRed-expressing cassette. Before sorting, the average fluorescence intensity of the Sf9 cell population was 3-fold higher than that of the High Five™ cell population. By enriching with the 10% strongest DsRed-fluorescent cells, the productivity of both cell populations could be successfully improved. The established sorting protocol potentiates the use of RMCE technology for recombinant protein production in insect cells.

  16. A plate reader-based method for cell water permeability measurement

    DEFF Research Database (Denmark)

    Fenton, Robert A.; Moeller, H B; Nielsen, S

    2010-01-01

    Cell volume and water permeability measurements in cultured mammalian cells are typically conducted under a light microscope. Many of the employed approaches are time consuming and not applicable to a study of confluent epithelial cell monolayers. We present here an adaptation of a calcein-quenching-based......-mannitol concentrations. Similarly, according average cell volumes have been measured in suspension in a Coulter counter (particle-sizing device). Based on these measurements, we have derived an equation that facilitates the modeling of cell volume changes based on fluorescence intensity changes. We have utilized...

  17. Cells that emerge from embryonic explants produce fibers of type IV collagen.

    Science.gov (United States)

    Chen, J M; Little, C D

    1985-10-01

    Double immunofluorescence staining experiments designed to examine the synthesis and deposition of collagen types I and IV in cultured explants of embryonic mouse lung revealed the presence of connective tissue-like fibers that were immunoreactive with anti-type IV collagen antibodies. This observation is contrary to the widely accepted belief that type IV collagen is found only in sheet-like arrangements beneath epithelia or as a sheath-like layer enveloping bundles of nerve or muscle cells. The extracellular matrix produced by cells that migrate from embryonic mouse lung rudiments in vitro was examined by double indirect immunofluorescence microscopy. Affinity-purified monospecific polyclonal antibodies were used to examine cells after growth on glass or native collagen substrata. The data show that embryonic mesenchymal cells can produce organized fibers of type IV collagen that are not contained within a basement membrane, and that embryonic epithelial cells deposit fibers and strands of type IV collagen beneath their basal surface when grown on glass; however, when grown on a rat tail collagen substratum the epithelial cells produce a fine meshwork. To our knowledge this work represents the first report that type IV collagen can be organized by cells into a fibrous extracellular matrix that is not a basement membrane.

  18. Hox6 genes modulate in vitro differentiation of mESCs to insulin-producing cells.

    Science.gov (United States)

    Larsen, Brian M; Marty-Santos, Leilani; Newman, Micaleah; Lukacs, Derek T; Spence, Jason R; Wellik, Deneen M

    2016-10-01

    The differentiation of glucose-responsive, insulin-producing cells from ESCs in vitro is promising as a cellular therapy for the treatment of diabetes, a devastating and common disease. Pancreatic β-cells are derived from the endoderm in vivo and therefore most current protocols attempt to generate a pure population of first endoderm, then pancreas epithelium, and finally insulin-producing cells. Despite this, differentiation protocols result in mixed populations of cells that are often poorly defined, but also contain mesoderm. Using an in vitro mESC-to-β cell differentiation protocol, we show that expression of region-specific Hox genes is induced. We also show that the loss of function of the Hox6 paralogous group, genes expressed only in the mesenchyme of the pancreas (not epithelium), affect the differentiation of insulin-producing cells in vitro. This work is consistent with the important role for these mesoderm-specific factors in vivo and highlights contribution of supporting mesenchymal cells in in vitro differentiation.

  19. Development of a brazing process for the production of water- cooled bipolar plates made of chromium-coated metal foils for PEM fuel cells

    Science.gov (United States)

    Mueller, M.; Hoehlich, D.; Scharf, I.; Lampke, T.; Hollaender, U.; Maier, H. J.

    2016-03-01

    Beside lithium batteries, PEM fuel cells are the most promising strategy as a power source to achieve the targets for introducing and increasing the usage of electric vehicles. Due to limited space and weight problems, water cooled, metallic bipolar plates in a fuel cell metal stack are preferred in motor vehicles. These plates are stamped metal sheets with a complex structure, interconnected media-tight. To meet the multiple tasks and requirements in use, complex and expensive combinations of materials are currently in use (carbon fiber composites, graphite, gold-plated nickel, stainless and acid resistant steel). The production of such plates is expensive as it is connected with considerable effort or the usage of precious metals. As an alternative, metalloid nitrides (CrN, VN, W2N, etc.) show a high chemical resistance, hardness and a good conductivity. So this material category meets the basic requirements of a top layer. However, the standard methods for their production (PVD, CVD) are expensive and have a slow deposition rate and a lower layer thicknesses. Because of these limitations, a full functionality over the life cycle of a bipolar plate is not guaranteed. The contribution shows the development and quantification of an alternative production process for bipolar plates. The expectation is to get significant advantages from the combination of chromium electrodeposition and thermochemical treatment to form chromium nitrides. Both processes are well researched and suitable for series production. The thermochemical treatment of the chromium layer also enables a process-integrated brazing.

  20. Fetal mesenchymal stromal cells differentiating towards chondrocytes acquire a gene expression profile resembling human growth plate cartilage.

    Directory of Open Access Journals (Sweden)

    Sandy A van Gool

    Full Text Available We used human fetal bone marrow-derived mesenchymal stromal cells (hfMSCs differentiating towards chondrocytes as an alternative model for the human growth plate (GP. Our aims were to study gene expression patterns associated with chondrogenic differentiation to assess whether chondrocytes derived from hfMSCs are a suitable model for studying the development and maturation of the GP. hfMSCs efficiently formed hyaline cartilage in a pellet culture in the presence of TGFβ3 and BMP6. Microarray and principal component analysis were applied to study gene expression profiles during chondrogenic differentiation. A set of 232 genes was found to correlate with in vitro cartilage formation. Several identified genes are known to be involved in cartilage formation and validate the robustness of the differentiating hfMSC model. KEGG pathway analysis using the 232 genes revealed 9 significant signaling pathways correlated with cartilage formation. To determine the progression of growth plate cartilage formation, we compared the gene expression profile of differentiating hfMSCs with previously established expression profiles of epiphyseal GP cartilage. As differentiation towards chondrocytes proceeds, hfMSCs gradually obtain a gene expression profile resembling epiphyseal GP cartilage. We visualized the differences in gene expression profiles as protein interaction clusters and identified many protein clusters that are activated during the early chondrogenic differentiation of hfMSCs showing the potential of this system to study GP development.

  1. Alumina-carbon nanofibers nanocomposites obtained by spark plasma sintering for proton exchange membrane fuel cell bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Borrell, A.; Torrecillas, R. [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN) Consejo Superior de Investigaciones Cientificas, Universidad de Oviedo, Principado de Asturias, Parque Tecnologico de Asturias, Llanera Asturias (Spain); Rocha, V.G.; Fernandez, A. [ITMA Materials Technology, Parque Tecnologico de Asturias, Llanera Asturias (Spain)

    2012-08-15

    There is an increasing demand of multifunctional materials for a wide variety of technological developments. Bipolar plates for proton exchange membrane fuel cells are an example of complex functionality components that must show among other properties high mechanical strength, electrical, and thermal conductivity. The present research explored the possibility of using alumina-carbon nanofibers (CNFs) nanocomposites for this purpose. In this study, it was studied for the first time the whole range of powder compositions in this system. Homogeneous powders mixtures were prepared and subsequently sintered by spark plasma sintering. The materials obtained were thoroughly characterized and compared in terms of properties required to be used as bipolar plates. The control on material microstructure and composition allows designing materials where mechanical or electrical performances are enhanced. A 50/50 vol.% alumina-CNFs composite appears to be a very promising material for this kind of application. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Ni/Cu/Ag plated contacts: A study of resistivity and contact adhesion for crystalline-Si solar cells

    Science.gov (United States)

    ur Rehman, Atteq; Lee, Sang Hee; Bhopal, Muhammad Fahad; Lee, Soo Hong

    2016-07-01

    Ni/Cu/Ag plated contacts were examined as an alternate to Ag screen printed contacts for silicon (Si) solar cell metallization. To realize a reliable contact for industrial applications, the contact resistance and its adhesion to Si substrates were evaluated. Si surface roughness by picosecond (ps) laser ablation of silicon-nitride (SiNx) antireflection coating (ARC) was done in order to prepare the patterns. The sintering process after Ni/Cu/Ag full metallization in the form of the post-annealing process was applied to investigate the contact resistivity and adhesion. A very low contact resistivity of approximately 0.5 mΩcm2 has been achieved with measurements made by the transfer length method (TLM). Thin finger lines of about 26 μm wide and a line resistance of 0.51 Ω/cm have been realized by plating technology. Improved contact adhesion by combining the ps-laser-ablation and post-annealing process has been achieved. We have shown the peel-off strengths >1 N/mm with a higher average adhesion of 1.9 N/mm. Our pull-tab adhesion tests demonstrate excellent strength well above the wafer breakage force. [Figure not available: see fulltext.

  3. Connexin-36 contributes to control function of insulin-producing cells.

    Science.gov (United States)

    Le Gurun, Sabine; Martin, David; Formenton, Andrea; Maechler, Pierre; Caille, Dorothee; Waeber, Gérard; Meda, Paolo; Haefliger, Jacques-Antoine

    2003-09-26

    Connexin-36 (Cx36) is a gap junction protein expressed by the insulin-producing beta-cells. We investigated the contribution of this protein in normal beta-cell function by using a viral gene transfer approach to alter Cx36 content in the insulin-producing line of INS-1E cells and rat pancreatic islets. Transcripts for Cx43, Cx45, and Cx36 were detected by reverse transcriptase-PCR in freshly isolated pancreatic islets, whereas only a transcript for Cx36 was detected in INS-1E cells. After infection with a sense viral vector, which induced de novo Cx36 expression in the Cx-defective HeLa cells we used to control the transgene expression, Western blot, immunofluorescence, and freeze-fracture analysis showed a large increase of Cx36 within INS-1E cell membranes. In contrast, after infection with an antisense vector, Cx36 content was decreased by 80%. Glucose-induced insulin release and insulin content were decreased, whether infected INS-1E cells expressed Cx36 levels that were largely higher or lower than those observed in wild-type control cells. In both cases, basal insulin secretion was unaffected. Comparable observations on basal secretion and insulin content were made in freshly isolated rat pancreatic islets. The data indicate that large changes in Cx36 alter insulin content and, at least in INS-1E cells, also affect glucose-induced insulin release.

  4. Ex situ evaluation of nanometer range gold coating on stainless steel substrate for automotive polymer electrolyte membrane fuel cell bipolar plate

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.; Ricketts, M.; Hirano, S. [Ford Motor Company, 2101 Village Road, Dearborn, MI 48121 (United States)

    2010-03-01

    The bipolar plate in polymer electrolyte membrane (PEM) fuel cell helps to feed reactant gases to the membrane electrode assembly (MEA) and collect current from the MEA. To facilitate these functions, the bipolar plate material should exhibit excellent electrical conductivity and corrosion resistance under fuel cell operating conditions, and simultaneously be of low-cost to meet commercialization enabling targets for automotive fuel cells. In the present work, we focus on the benchmarking of 10 nm gold coated SS316L (a.k.a. Au Nanoclad {sup registered}) bipolar plate material through ex situ tests, which is provided by Daido Steel (Japan). The use of nanometer range Au coatings help to retain the noble properties of gold while significantly reducing the cost of the bipolar plate. The area specific resistance of the flat sample is 0.9 m{omega} cm{sup 2} while that for the formed bipolar plate is 6.3 m{omega} cm{sup 2} at compaction force of 60 N cm{sup -2}. The corrosion current density was less than 1 {mu}A cm{sup -2} at 0.8 V/NHE with air sparge simulating cathodic conditions. Additionally, gold coated SS316L showed anodic passivation of SS316L, thereby exhibiting robustness towards coating defects including surface scratches that may originate during the manufacturing of the bipolar plate. These series of ex situ tests indicate that 10 nm gold coated SS316L has good potential to be considered for commercial bipolar plates in automotive fuel cell stack. (author)

  5. Liver sinusoidal endothelial cells induce immunosuppressive IL-10-producing Th1 cells via the Notch pathway.

    Science.gov (United States)

    Neumann, Katrin; Rudolph, Christine; Neumann, Christian; Janke, Marko; Amsen, Derk; Scheffold, Alexander

    2015-07-01

    Under homeostasis, liver sinusoidal endothelial cells (LSECs) shift intrahepatic T-cell responses towards tolerance. However, the role of LSECs in the regulation of T-cell-induced liver inflammation is less clear. Here, we studied the capacity of LSECs to modulate pro-inflammatory Th1-cell differentiation in mice. Using in vitro co-culture systems and subsequent cytokine analysis, we showed that LSECs induced high amounts of the anti-inflammatory cytokine IL-10 in developing Th1 cells. These LSEC-stimulated Th1 cells had no pro-inflammatory capacity in vivo but instead actively suppressed an inflammatory Th1-cell-induced delayed-type hypersensitivity reaction. Blockage of IL-10 signaling in vivo inhibited immunosuppressive activity of LSEC-stimulated Th1 cells. We identified the Notch pathway as a mechanism how LSECs trigger IL-10 expression in Th1 cells. LSECs expressed high levels of the Delta-like and Jagged family of Notch ligands and induced expression of the Notch target genes hes-1 and deltex-1 in Th1 cells. Blockade of Notch signaling selectively inhibited IL-10 induction in Th1 cells by LSECs. Our findings suggest that LSEC-induced IL-10 expression in Th1 cells via the Notch pathway may contribute to the control of hepatic inflammatory immune responses by induction of a self-regulatory mechanism in pro-inflammatory Th1 cells.

  6. Effects of bath composition on the morphology of electroless-plated Cu electrodes for hetero-junctions with intrinsic thin layer solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woon Young [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Lee, Yu Jin [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Department of Materials Science & Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Lee, Min Hyung, E-mail: minhyung@kitech.re.kr [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of)

    2015-07-31

    The morphology of an electroless-plated Cu electrode was investigated as a function of bath composition. To enhance the selectivity of Cu electrode deposition on the surface of an indium tin oxide layer, a Ti/Cu multi-layer was deposited as a Cu electrode seed layer by physical vapor deposition, and then electroless plating was performed using various complexing agents and a surfactant. The degree of selectivity was effectively influenced by the type of complexing agent. The electroless plating solution containing N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) as complexing agent showed excellent selective growth of the Cu electrode as compared to the solution containing ethylenediaminetetraacetic acid. Even though THPED led to better selective growth of the electroless-plated Cu electrode, the aspect ratio of electrode lateral growth was about 2.7 times that of vertical growth. By adding a nonionic surfactant, the ratio between vertical growth rate and lateral growth rate was improved about 4.6 times. The Cu–THPED electroless plating with nonionic surfactant provided a drastic decrease in lateral growth rate, compared with the Cu–THPED electroless plating bath excluding nonionic surfactant. The Cu–THPED solution including nonionic surfactant is a promising composition of electroless plating solution for the clear selective plating of Cu electrodes on hetero-junctions with intrinsic thin layer solar cells. - Highlights: • Selective electroless plating (SEP) depends on binding strength of complexing agent. • The SEP was performed using Cu-N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine. • A surfactant is able to remove hydrogen bubbles on Cu electrode surface. • The growth of Cu electrode was improved in vertical direction by adding surfactant.

  7. Immobilized gellan sulfate surface for cell adhesion and multiplication: development of cell-hybrid biomaterials using self-produced fibronectin.

    Science.gov (United States)

    Miyamoto, Keiichi; Kanemoto, Akiko; Hashimoto, Kenichi; Tokita, Masayuki; Komai, Takashi

    2002-04-08

    A new concept for cell-hybrid biomaterial is proposed in which human unbilical vein endothelial cells (HUVEC) are adhered to an immobilized gellan sulfate (GS) surface. Extra domain A containing fibronectin (EDA(+)FN) released from HUVEC is necessary for cell adhesion and multiplication. The material design in this study is based on these self-released cell adhesion proteins. The interaction between GS and EDA(+)FN was evaluated using the affinity constant (KA); the value obtained was 1.03x10(8) (M(-1)). These results suggest that the adhesion of HUVEC to GS may be supported by the adhesion of EDA(+)FN to GS. We also found that this new material adheres to HUVEC, allowing the reintroduction of EDA(+)FN, which is self-produced by the cell. This material is relatively easy to produce, not requiring the usual coating of adhesion proteins in pretreatment.

  8. [A case of alpha-cell nesidioblastosis and hyperplasia with multiple glucagon-producing endocrine cell tumor of the pancreas].

    Science.gov (United States)

    Kang, Huapyong; Kim, Sewha; Lim, Tae Seop; Lee, Hye Won; Choi, Heun; Kang, Chang Moo; Kim, Ho Guen; Bang, Seungmin

    2014-04-01

    Nesidioblastosis is a term used to describe pathologic overgrowth of pancreatic islet cells. It also means maldistribution of islet cells within the ductules of exocrine pancreas. Generally, nesidioblastosis occurs in beta-cell and causes neonatal hyperinsulinemic hypoglycemia or adult noninsulinoma pancreatogenous hypoglycemia syndrome. Alpha-cell nesidioblastosis and hyperplasia is an extremely rare disorder. It often accompanies glucagon-producing marco- and mircoadenoma without typical glucagonoma syndrome. A 35-year-old female was referred to our hospital with recurrent acute pancreatitis. On radiologic studies, 1.5 cm sized mass was noted in pancreas tail. Cytological evaluation with EUS-fine-needle aspiration suggested serous cystadenoma. She received distal pancreatectomy. The histologic examination revealed a 1.7 cm sized neuroendocrine tumor positive for immunohistochemical staining with glucagon antibody. Multiple glucagon-producing micro endocrine cell tumors were scattered next to the main tumor. Additionally, diffuse hyperplasia of pancreatic islets and ectopic proliferation of islet cells in centroacinar area, findings compatible to nesidioblastosis, were seen. These hyperplasia and almost all nesidioblastic cells were positive for glucagon immunochemistry. Even though serum glucagon level still remained higher than the reference value, she has been followed-up without any evidence of recurrence or hormone related symptoms. Herein, we report a case of alpha-cell nesidioblastosis and hyperplasia combined with glucagon-producing neuroendocrine tumor with literature review.

  9. Platelet Lysates Produced from Expired Platelet Concentrates Support Growth and Osteogenic Differentiation of Mesenchymal Stem Cells

    OpenAIRE

    Sandra Mjoll Jonsdottir-Buch; Ramona Lieder; Olafur Eysteinn Sigurjonsson

    2013-01-01

    BACKGROUND: Mesenchymal stem cells are promising candidates in regenerative cell therapy. Conventional culture methods involve the use of animal substances, specifically fetal bovine serum as growth supplement. Since the use of animal-derived products is undesirable for human applications, platelet lysates produced from human platelets are an attractive alternative. This is especially true if platelet lysates from already approved transfusion units at blood banks can be utilized. The purpose ...

  10. Stable producer cell lines for adeno-associated virus (AAV) assembly.

    Science.gov (United States)

    Chadeuf, Gilliane; Salvetti, Anna

    2010-10-01

    Stable producer cell lines containing both the rep and cap genes and recombinant adeno-associated virus (rAAV) vectors can be infected with a helper virus to provide reliable and efficient production of rAAV stocks. However, the development of these cell lines is time-consuming. The procedure described here is therefore recommended only for studies requiring the production of high amounts of rAAV, such as preclinical studies performed in large animals.

  11. Some tests of flat plate photovoltaic module cell temperatures in simulated field conditions

    Science.gov (United States)

    Griffith, J. S.; Rathod, M. S.; Paslaski, J.

    1981-01-01

    The nominal operating cell temperature (NOCT) of solar photovoltaic (PV) modules is an important characteristic. Typically, the power output of a PV module decreases 0.5% per deg C rise in cell temperature. Several tests were run with artificial sun and wind to study the parametric dependencies of cell temperature on wind speed and direction and ambient temperature. It was found that the cell temperature is extremely sensitive to wind speed, moderately so to wind direction and rather insensitive to ambient temperature. Several suggestions are made to obtain data more typical of field conditions.

  12. Investigation of bio-inspired flow channel designs for bipolar plates in proton exchange membrane fuel cells

    Science.gov (United States)

    Kloess, Jason P.; Wang, Xia; Liu, Joan; Shi, Zhongying; Guessous, Laila

    Proton exchange membrane (PEM) fuel cell performance is directly related to the flow channel design on bipolar plates. Power gains can be found by varying the type, size, or arrangement of channels. The objective of this paper is to present two new flow channel patterns: a leaf design and a lung design. These bio-inspired designs combine the advantages of the existing serpentine and interdigitated patterns with inspiration from patterns found in nature. Both numerical simulation and experimental testing have been conducted to investigate the effects of two new flow channel patterns on fuel cell performance. From the numerical simulation, it was found that there is a lower pressure drop from the inlet to outlet in the leaf or lung design than the existing serpentine or interdigitated flow patterns. The flow diffusion to the gas diffusion layer was found be to more uniform for the new flow channel patterns. A 25 cm 2 fuel cell was assembled and tested for four different flow channels: leaf, lung, serpentine and interdigitated. The polarization curve has been obtained under different operating conditions. It was found that the fuel cell with either leaf or lung design performs better than the convectional flow channel design under the same operating conditions. Both the leaf and lung design show improvements over previous designs by up to 30% in peak power density.

  13. Investigation of bio-inspired flow channel designs for bipolar plates in proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kloess, Jason P. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI (United States); Wang, Xia; Shi, Zhongying; Guessous, Laila [Department of Mechanical Engineering, Oakland University, Rochester, MI 48309 (United States); Liu, Joan [Department of Mechanical Engineering, Olin College of Engineering, MA (United States)

    2009-03-01

    Proton exchange membrane (PEM) fuel cell performance is directly related to the flow channel design on bipolar plates. Power gains can be found by varying the type, size, or arrangement of channels. The objective of this paper is to present two new flow channel patterns: a leaf design and a lung design. These bio-inspired designs combine the advantages of the existing serpentine and interdigitated patterns with inspiration from patterns found in nature. Both numerical simulation and experimental testing have been conducted to investigate the effects of two new flow channel patterns on fuel cell performance. From the numerical simulation, it was found that there is a lower pressure drop from the inlet to outlet in the leaf or lung design than the existing serpentine or interdigitated flow patterns. The flow diffusion to the gas diffusion layer was found be to more uniform for the new flow channel patterns. A 25 cm{sup 2} fuel cell was assembled and tested for four different flow channels: leaf, lung, serpentine and interdigitated. The polarization curve has been obtained under different operating conditions. It was found that the fuel cell with either leaf or lung design performs better than the convectional flow channel design under the same operating conditions. Both the leaf and lung design show improvements over previous designs by up to 30% in peak power density. (author)

  14. Chinese Experts Successfully Produced Transgenic Animals from Haploid Embryonic Stem Cells

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Individual animals produced by haploid stem cells are ideal models for studying recessive genes. Hap- loid stem cells not only can maintain haploidy, but also are capable of replicating themselves infinitely. Modified genes can be passed on to future generations through genetic engineering of haploid embryonic stem cells, which thus avoids the germlinechimerism caused by other transgenic methods and greatly im- proves the analysis efficiency of the function of gene modification. However, natural haploids are only re- stricted to germline cells in mammals. Currently in mammals, only the embryonic stem cells in rats and mice can be used as the carrier of gene modification, but the embryonic stem cells of other mammals, in- eluding primates, cannot guarantee germline transmission, which has seriously hindered the establishment of disease models by using these species.

  15. Glucagon-producing cells are increased in Mas-deficient mice.

    Science.gov (United States)

    Felix Braga, Janaína; Ravizzoni Dartora, Daniela; Alenina, Natalia; Bader, Michael; Santos, Robson Augusto Souza

    2017-01-01

    It has been shown that angiotensin(1-7) (Ang(1-7)) produces several effects related to glucose homeostasis. In this study, we aimed to investigate the effects of genetic deletion of Ang(1-7), the GPCR Mas, on the glucagon-producing cells. C57BL6/N Mas(-/-) mice presented a significant and marked increase in pancreatic α-cells (number of cells: 146 ± 21 vs 67 ± 8 in WT; P Mas(-/-) mice (0.25 ± 0.01 vs 0.31 ± 56.45 pg/mL in WT; P = 0.02). In order to eliminate the possibility of a background-related phenotype, we determined the number of glucagon-producing cells in FVB/N Mas(-/-) mice. In keeping with the observations in C57BL6/N Mas(-/-) mice, the number and percentage of pancreatic α-cells were also significantly increased in these mice (number of α-cells: 260 ± 22 vs 156 ± 12 in WT, P Mas has a previously unexpected role on the pancreatic glucagon production. © 2017 The authors.

  16. Elastomer based composite materials for bipolar plates in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Petrach, Elaine M.

    2011-07-01

    In most investigations, polymer conductive composite bipolar plates have failed to achieve the low resistivity required for PEMFCs. The goal of this dissertation is to investigate whether a composite of conductive fillers and a two-phase polymeric matrix will achieve low resistivity through preferred distribution of the fillers at the interface of the two phases. The use of an elastomer as one component of the blend will impart fracture resistance. Three types of matrices were investigated, a single phase polyvinyl ester plastic matrix, a compatible one-phase blend of polyvinyl ester (VER) and polyurethane (PU) elastomer, and a two-phase system of polyvinyl ester and ethylene propylene diene monomer (EPDM) elastomer. The different phases were determined by the theory of mixing. When solubility parameters are closer together it is likely that the system will be one phase. The one and two-phase systems were analyzed within the composition containing natural Cytec DKD graphite fibers, Asbury synthetic graphite 4012 flakes and ultra high surface area synthetic graphite TC 307. Phase systems affect the mechanical, electrical, and thermal properties. The percolation theory analysis was applied to determine the optimal percentage of conductive fillers and polymer blends. The optimal composition for composite materials consisted of 35vo1% of conductive fillers and 65vo1% of a two-phase blend matrix. The conductive filler included 3vol% of synthetic graphite TC307, 25.5vol% of Cytec DKD graphite fibers and 6.5vol% of Asbury synthetic graphite 4012 flakes. The two-phase blend matrix included 40vol% of EPDM to 60vol% of VER. This resulted in an electrical resistivity of 0.009O-cm and a thermal conductivity of 11.6W/m-K. The two-phase blend matrix added more ductility to the composition with the ability to withstand a stress of 10MPa with over 1% strain applied to the overall composite bipolar plates. The composition also absorbed 60% more mechanical energy than that

  17. Surface composition effect of nitriding Ni-free stainless steel as bipolar plate of polymer electrolyte fuel cell

    Science.gov (United States)

    Yu, Yang; Shironita, Sayoko; Nakatsuyama, Kunio; Souma, Kenichi; Umeda, Minoru

    2016-12-01

    In order to increase the corrosion resistance of low cost Ni-free SUS445 stainless steel as the bipolar plate of a polymer electrolyte fuel cell, a nitriding surface treatment experiment was carried out in a nitrogen atmosphere under vacuum conditions, while an Ar atmosphere was used for comparison. The electrochemical performance, microstructure, surface chemical composition and morphology of the sample before and after the electrochemical measurements were investigated using linear sweep voltammetry (LSV), X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GDS) and laser scanning microscopy (LSM) measurements. The results confirmed that the nitriding heat treatment not only increased the corrosion resistance, but also improved the surface conductivity of the Ni-free SUS445 stainless steel. In contrast, the corrosion resistance of the SUS445 stainless steel decreased after heat treatment in an Ar atmosphere. These results could be explained by the different surface compositions between these samples.

  18. Radial Wavelet Neural Network with a Novel Self-Creating Disk-Cell-Splitting Algorithm for License Plate Character Recognition

    Directory of Open Access Journals (Sweden)

    Rong Cheng

    2015-06-01

    Full Text Available In this paper, a novel self-creating disk-cell-splitting (SCDCS algorithm is proposed for training the radial wavelet neural network (RWNN model. Combining with the least square (LS method which determines the linear weight coefficients, SCDCS can create neurons adaptively on a disk according to the distribution of input data and learning goals. As a result, a disk map is made for input data as well as a RWNN model with proper architecture and parameters can be decided for the recognition task. The proposed SCDCS-LS based RWNN model is employed for the recognition of license plate characters. Compared to the classical radial-basis-function (RBF network with K-means clustering and LS, the proposed model can make a better recognition performance even with fewer neurons.

  19. A Rapid Culture Technique Produces Functional Dendritic-Like Cells from Human Acute Myeloid Leukemia Cell Lines

    Directory of Open Access Journals (Sweden)

    Jian Ning

    2011-01-01

    Full Text Available Most anti-cancer immunotherapeutic strategies involving dendritic cells (DC as vaccines rely upon the adoptive transfer of DC loaded with exogenous tumour-peptides. This study utilized human acute myeloid leukemia (AML cells as progenitors from which functional dendritic-like antigen presenting cells (DLC were generated, that constitutively express tumour antigens for recognition by CD8+ T cells. DLC were generated from AML cell lines KG-1 and MUTZ-3 using rapid culture techniques and appropriate cytokines. DLC were evaluated for their cell-surface phenotype, antigen uptake and ability to stimulate allogeneic responder cell proliferation, and production of IFN-γ; compared with DC derived from normal human PBMC donors. KG-1 and MUTZ-3 DLC increased expression of CD80, CD83, CD86, and HLA-DR, and MUTZ-3 DLC downregulated CD14 and expressed CD1a. Importantly, both KG-1 and MUTZ-3-derived DLC promoted proliferation of allogeneic responder cells more efficiently than unmodified cells; neither cells incorporated FITC-labeled dextran, but both stimulated IFN-γ production from responding allogeneic CD8+ T cells. Control DC produced from PBMC using the FastDC culture also expressed high levels of critical cell surface ligands and demonstrated good APC function. This paper indicates that functional DLC can be cultured from the AML cell lines KG-1 and MUTZ-3, and FastDC culture generates functional KG-1 DLC.

  20. Effect of Acteoside as a Cell Protector to Produce a Cloned Dog

    Science.gov (United States)

    Kim, Keun Jung; Kim, Eun Young; Kim, Dong-hee; Lee, Bo Myeong; Han, Kil Woo; Park, Kang-Sun; Lee, Kyung-Bon; Kim, Min Kyu

    2016-01-01

    Somatic cell nuclear transfer (SCNT) is a well-known laboratory technique. The principle of the SCNT involves the reprogramming a somatic nucleus by injecting a somatic cell into a recipient oocyte whose nucleus has been removed. Therefore, the nucleus donor cells are considered as a crucial factor in SCNT. Cell cycle synchronization of nucleus donor cells at G0/G1 stage can be induced by contact inhibition or serum starvation. In this study, acteoside, a phenylpropanoid glycoside compound, was investigated to determine whether it is applicable for inducing cell cycle synchronization, cytoprotection, and improving SCNT efficiency in canine fetal fibroblasts. Primary canine fetal fibroblasts were treated with acteoside (10, 30, 50 μM) for various time periods (24, 48 and 72 hours). Cell cycle synchronization at G0/G1 stage did not differ significantly with the method of induction: acteoside treatment, contact inhibition or serum starvation. However, of these three treatments, serum starvation resulted in significantly increased level of reactive oxygen species (ROS) (99.5 ± 0.3%) and apoptosis. The results also revealed that acteoside reduced ROS and apoptosis processes including necrosis in canine fetal fibroblasts, and improved the cell survival. Canine fetal fibroblasts treated with acteoside were successfully arrested at the G0/G1 stage. Moreover, the reconstructed embryos using nucleus donor cells treated with acteoside produced a healthy cloned dog, but not the embryos produced using nucleus donor cells subjected to contact inhibition. In conclusion, acteoside induced cell cycle synchronization of nucleus donor cells would be an alternative method to improve the efficiency of canine SCNT because of its cytoprotective effects. PMID:27428333

  1. De Novo Formation of Insulin-Producing “Neo-β Cell Islets” from Intestinal Crypts

    Directory of Open Access Journals (Sweden)

    Yi-Ju Chen

    2014-03-01

    Full Text Available The ability to interconvert terminally differentiated cells could serve as a powerful tool for cell-based treatment of degenerative diseases, including diabetes mellitus. To determine which, if any, adult tissues are competent to activate an islet β cell program, we performed an in vivo screen by expressing three β cell “reprogramming factors” in a wide spectrum of tissues. We report that transient intestinal expression of these factors—Pdx1, MafA, and Ngn3 (PMN—promotes rapid conversion of intestinal crypt cells into endocrine cells, which coalesce into “neoislets” below the crypt base. Neoislet cells express insulin and show ultrastructural features of β cells. Importantly, intestinal neoislets are glucose-responsive and able to ameliorate hyperglycemia in diabetic mice. Moreover, PMN expression in human intestinal “organoids” stimulates the conversion of intestinal epithelial cells into β-like cells. Our results thus demonstrate that the intestine is an accessible and abundant source of functional insulin-producing cells.

  2. Comparison of the transcriptomic profile of hepatic human induced pluripotent stem like cells cultured in plates and in a 3D microscale dynamic environment.

    Science.gov (United States)

    Leclerc, Eric; Kimura, Keiichi; Shinohara, Marie; Danoy, Mathieu; Le Gall, Morgane; Kido, Taketomo; Miyajima, Atsushi; Fujii, Teruo; Sakai, Yasuyuki

    2017-01-01

    We have compared the transcriptomic profiles of human induced pluripotent stem cells after their differentiation in hepatocytes like cells in plates and microfluidic biochips. The biochips provided a 3D and dynamic support during the cell differentiation when compared to the 2D static cultures in plates. The microarray have demonstrated the up regulation of important pathway related to liver development and maturation during the culture in biochips. Furthermore, the results of the transcriptomic profile, coupled with immunostaining, and RTqPCR analysis have shown typical biomarkers illustrating the presence of responders of biliary like cells, hepatocytes like cells, and endothelial like cells. However, the overall tissue still presented characteristic of immature and foetal patterns. Nevertheless, the biochip culture provided a specific micro-environment in which a complex multicellular differentiation toward liver could be oriented.

  3. Bone Marrow Homing Enriches Stem Cells Responsible for Neogenesis of Insulin-Producing Cells, While Radiation Decreases Homing Efficiency.

    Science.gov (United States)

    Goldenberg-Cohen, Nitza; Iskovich, Svetlana; Askenasy, Nadir

    2015-10-01

    Small-sized adult bone marrow cells isolated by counterflow centrifugal elutriation and depleted of lineage markers (Fr25lin(-)) have the capacity to differentiate into insulin-producing cells and stabilize glycemic control. This study assessed competitive migration of syngeneic stem cells to the bone marrow and islets in a murine model of chemical diabetes. VLA-4 is expressed in ∼ 25% of these cells, whereas CXCR4 is not detected, however, it is transcriptionally upregulated (6-fold). The possibility to enrich stem cells by a bone marrow homing (BM-H) functional assay was assessed in sequential transplants. Fr25lin(-) cells labeled with PKH26 were grafted into primary myeloablated recipients, and mitotically quiescent Fr25lin(-)PKH(bright) cells were sorted from the bone marrow after 2 days. The contribution of bone marrow-homed stem cells was remarkably higher in secondary recipients compared to freshly elutriated cells. The therapeutic efficacy was further increased by omission of irradiation in the secondary recipients, showing a 25-fold enrichment of islet-reconstituting cells by the bone marrow homing assay. Donor cells identified by the green fluorescent protein (GFP) and a genomic marker in sex-mismatched transplants upregulated PDX-1 and produced proinsulin, affirming the capacity of BM-H cells to convert in the injured islets. There was no evidence of transcriptional priming of freshly elutriated subsets to express PDX-1, insulin, and other markers of endocrine progenitors, indicating that the bone marrow harbors stem cells with versatile differentiation capacity. Affinity to the bone marrow can be used to enrich stem cells for pancreatic regeneration, and reciprocally, conditioning reduces the competitive incorporation in the injured islets.

  4. A cell shrinkage artefact in growth plate chondrocytes with common fixative solutions: importance of fixative osmolarity for maintaining morphology

    Directory of Open Access Journals (Sweden)

    MY Loqman

    2010-05-01

    Full Text Available The remarkable increase in chondrocyte volume is a major determinant in the longitudinal growth of mammalian bones. To permit a detailed morphological study of hypertrophic chondrocytes using standard histological techniques, the preservation of normal chondrocyte morphology is essential. We noticed that during fixation of growth plates with conventional fixative solutions, there was a marked morphological (shrinkage artifact, and we postulated that this arose from the hyper-osmotic nature of these solutions. To test this, we fixed proximal tibia growth plates of 7-day-old rat bones in either (a paraformaldehyde (PFA; 4%, (b glutaraldehyde (GA; 2% with PFA (2% with ruthenium hexamine trichloride (RHT; 0.7%, (c GA (2% with RHT (0.7%, or (d GA (1.3% with RHT (0.5% and osmolarity adjusted to a ‘physiological’ level of ~280mOsm. Using conventional histological methods, confocal microscopy, and image analysis on fluorescently-labelled fixed and living chondrocytes, we then quantified the extent of cell shrinkage and volume change. Our data showed that the high osmolarity of conventional fixatives caused a shrinkage artefact to chondrocytes. This was particularly evident when whole bones were fixed, but could be markedly reduced if bones were sagittally bisected prior to fixation. The shrinkage artefact could be avoided by adjusting the osmolarity of the fixatives to the osmotic pressure of normal extracellular fluids (~280mOsm. These results emphasize the importance of fixative osmolarity, in order to accurately preserve the normal volume/morphology of cells within tissues.

  5. Effect of nitrogen-rich cell culture surfaces on type X collagen expression by bovine growth plate chondrocytes

    Science.gov (United States)

    2011-01-01

    Background Recent evidence indicates that osteoarthritis (OA) may be a systemic disease since mesenchymal stem cells (MSCs) from OA patients express type X collagen, a marker of late stage chondrocyte hypertrophy (associated with endochondral ossification). We recently showed that the expression of type X collagen was suppressed when MSCs from OA patients were cultured on nitrogen (N)-rich plasma polymer layers, which we call "PPE:N" (N-doped plasma-polymerized ethylene, containing up to 36 atomic percentage (at.% ) of N. Methods In the present study, we examined the expression of type X collagen in fetal bovine growth plate chondrocytes (containing hypertrophic chondrocytes) cultured on PPE:N. We also studied the effect of PPE:N on the expression of matrix molecules such as type II collagen and aggrecan, as well as on proteases (matrix metalloproteinase-13 (MMP-13) and molecules implicated in cell division (cyclin B2). Two other culture surfaces, "hydrophilic" polystyrene (PS, regular culture dishes) and nitrogen-containing cation polystyrene (Primaria®), were also investigated for comparison. Results Results showed that type X collagen mRNA levels were suppressed when cultured for 4 days on PPE:N, suggesting that type X collagen is regulated similarly in hypertrophic chondrocytes and in human MSCs from OA patients. However, the levels of type X collagen mRNA almost returned to control value after 20 days in culture on these surfaces. Culture on the various surfaces had no significant effects on type II collagen, aggrecan, MMP-13, and cyclin B2 mRNA levels. Conclusion Hypertrophy is diminished by culturing growth plate chondrocytes on nitrogen-rich surfaces, a mechanism that is beneficial for MSC chondrogenesis. Furthermore, one major advantage of such "intelligent surfaces" over recombinant growth factors for tissue engineering and cartilage repair is potentially large cost-saving. PMID:21244651

  6. SnO2:F Coated Duplex Stainless Steel for PEM Fuel Cell Bipolar Plates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Turner, J. A.

    2008-01-01

    Duplex 2205 stainless steel was deposited with 0.6 {micro}m thick SnO2:F coating; coated steel was characterized for PEMFC bipolar plate application. Compared with bare alloy, interfacial contact resistance (ICR) values of the coated 2205 steel are higher. SnO2:F coating adds its own resistance to the air-formed film on the steel. In a PEMFC anode environment, a current peak of ca. 25 {micro}A/cm2 registered at ca. 30 min for coated 2205 steel. It stabilized at ca. 2.0 {approx} -1.0 {micro}A/cm2. This peak is related to the complicated process of coating dissolution and oxide-layer formation. Anodic-cathodic current transfer occurred at ca. 200 min polarization. In a PEMFC cathode environment, current was stable immediately after polarization. The stable current was ca. 0.5 {approx} 2.0 {micro}A/cm2 during the entire polarization period. AES depth profiles with tested samples and ICP analysis with the tested solutions confirmed the excellent corrosion resistance of the SnO2:F coated 2205 alloy in simulated PEMFC environments.

  7. Platelet lysates produced from expired platelet concentrates support growth and osteogenic differentiation of mesenchymal stem cells.

    Directory of Open Access Journals (Sweden)

    Sandra Mjoll Jonsdottir-Buch

    Full Text Available BACKGROUND: Mesenchymal stem cells are promising candidates in regenerative cell therapy. Conventional culture methods involve the use of animal substances, specifically fetal bovine serum as growth supplement. Since the use of animal-derived products is undesirable for human applications, platelet lysates produced from human platelets are an attractive alternative. This is especially true if platelet lysates from already approved transfusion units at blood banks can be utilized. The purpose of this study was to produce human platelet lysates from expired, blood bank-approved platelet concentrates and evaluate their use as growth supplement in the culture of mesenchymal stem cells. METHODOLOGY/PRINCIPAL FINDINGS: In this study, bone marrow-derived mesenchymal stem cells were cultured with one of three culture supplements; fetal bovine serum, lysates from freshly prepared human platelet concentrates, or lysates from expired human platelet concentrates. The effects of these platelet-derived culture supplements on basic mesenchymal stem cell characteristics were evaluated. All cultures maintained the typical mesenchymal stem cell surface marker expression, trilineage differentiation potential, and the ability to suppress in vitro immune responses. However, mesenchymal stem cells supplemented with platelet lysates proliferated faster than traditionally cultured cells and increased the expression of the osteogenic marker gene RUNX-2; yet no difference between the use of fresh and expired platelet concentrates was observed. CONCLUSION/SIGNIFICANCE: Our findings suggest that human platelet lysates produced from expired platelet concentrates can be used as an alternative to fetal bovine serum for mesenchymal stem cell culture to the same extent as lysates from fresh platelets.

  8. MicroRNA-146a expresses in interleukin-17 producing T cells in rheumatoid arthritis patients

    Directory of Open Access Journals (Sweden)

    Niimoto Takuya

    2010-09-01

    Full Text Available Abstract Background Interleukin (IL-17 is an important factor in rheumatoid arthritis (RA pathogenesis. MicroRNA (miRNAs are a family of non coding RNAs and associated with human diseases including RA. The purpose of this study is to identify the miRNAs in the differentiation of IL-17 producing cells, and analyze their expression pattern in the peripheral blood mononuclear cells (PBMC and synovium from RA patients. Methods IL-17 producing cells were expanded from CD4+T cell. MiRNA microarray was performed to identify the miRNAs in the differentiation of IL-17 producing cells. Quantitative polymerase chain reaction was performed to examine the expression patterns of the identified miRNAs in the PBMC and synovium from RA and osteoarthritis (OA patients. Double staining combining in situ hybridization and immunohistochemistry of IL-17 was performed to analyze the expression pattern of identified miRNA in the synovium. Results Six miRNAs, let-7a, miR-26, miR-146a/b, miR-150, and miR-155 were significantly up regulated in the IL-17 producing T cells. The expression of miR-146a and IL-17 was higher than in PBMC in the patients with low score of Larsen grade and short disease duration. MiR-146a intensely expressed in RA synovium in comparison to OA. MiR-146a expressed intensely in the synovium with hyperplasia and high expression of IL-17 from the patients with high disease activity. Double staining revealed that miR-146a expressed in IL-17 expressing cells. Conclusion These results indicated that miR-146a was associated with IL-17 expression in the PBMC and synovium in RA patients. There is the possibility that miR-146a participates in the IL-17 expression.

  9. ANGPTL4 is produced by entero-endocrine cells in the human intestinal tract

    NARCIS (Netherlands)

    Alex, S.; Lichtenstein, L.L.; Dijk, W.; Mensink, R.P.; Tan, N.S.; Kersten, A.H.

    2014-01-01

    Gut hormones produced by entero-endocrine cells (EEC) located throughout the gastrointestinal tract play a major role in the regulation of glucose and energy homeostasis. Angiopoietin-like 4 (ANGPTL4, also referred to as fasting induced adipose factor) is a secreted factor involved in regulation of

  10. Bet-hedging in bacteriocin producing Escherichia coli populations: the single cell perspective

    Science.gov (United States)

    Bayramoglu, Bihter; Toubiana, David; van Vliet, Simon; Inglis, R. Fredrik; Shnerb, Nadav; Gillor, Osnat

    2017-02-01

    Production of public goods in biological systems is often a collaborative effort that may be detrimental to the producers. It is therefore sustainable only if a small fraction of the population shoulders the cost while the majority reap the benefits. We modelled this scenario using Escherichia coli populations producing colicins, an antibiotic that kills producer cells’ close relatives. Colicin expression is a costly trait, and it has been proposed that only a small fraction of the population actively expresses the antibiotic. Colicinogenic populations were followed at the single-cell level using time-lapse microscopy, and showed two distinct, albeit dynamic, subpopulations: the majority silenced colicin expression, while a small fraction of elongated, slow-growing cells formed colicin-expressing hotspots, placing a significant burden on expressers. Moreover, monitoring lineages of individual colicinogenic cells showed stochastic switching between expressers and non-expressers. Hence, colicin expressers may be engaged in risk-reducing strategies—or bet-hedging—as they balance the cost of colicin production with the need to repel competitors. To test the bet-hedging strategy in colicin-mediated interactions, competitions between colicin-sensitive and producer cells were simulated using a numerical model, demonstrating a finely balanced expression range that is essential to sustaining the colicinogenic population.

  11. IL-17 produced by Paneth cells drives TNF-induced shock.

    NARCIS (Netherlands)

    Takahashi, N.; Laere, I. van; Rycke, R de; Cauwels, A.; Joosten, L.A.B.; Lubberts, E.; Berg, W.B. van den; Libert, C.

    2008-01-01

    Tumor necrosis factor (TNF) has very potent antitumor activity, but it also provokes a systemic inflammatory response syndrome that leads to shock, organ failure, and death. Here, we demonstrate that interleukin (IL)-17, a proinflammatory cytokine known to be produced mainly by activated T cells, ha

  12. Bet-hedging in bacteriocin producing Escherichia coli populations: the single cell perspective

    Science.gov (United States)

    Bayramoglu, Bihter; Toubiana, David; van Vliet, Simon; Inglis, R. Fredrik; Shnerb, Nadav; Gillor, Osnat

    2017-01-01

    Production of public goods in biological systems is often a collaborative effort that may be detrimental to the producers. It is therefore sustainable only if a small fraction of the population shoulders the cost while the majority reap the benefits. We modelled this scenario using Escherichia coli populations producing colicins, an antibiotic that kills producer cells’ close relatives. Colicin expression is a costly trait, and it has been proposed that only a small fraction of the population actively expresses the antibiotic. Colicinogenic populations were followed at the single-cell level using time-lapse microscopy, and showed two distinct, albeit dynamic, subpopulations: the majority silenced colicin expression, while a small fraction of elongated, slow-growing cells formed colicin-expressing hotspots, placing a significant burden on expressers. Moreover, monitoring lineages of individual colicinogenic cells showed stochastic switching between expressers and non-expressers. Hence, colicin expressers may be engaged in risk-reducing strategies—or bet-hedging—as they balance the cost of colicin production with the need to repel competitors. To test the bet-hedging strategy in colicin-mediated interactions, competitions between colicin-sensitive and producer cells were simulated using a numerical model, demonstrating a finely balanced expression range that is essential to sustaining the colicinogenic population. PMID:28165017

  13. Cinacalcet for hypercalcemia caused by pulmonary squamous cell carcinoma producing parathyroid hormone-related Peptide

    NARCIS (Netherlands)

    Bech, A.; Smolders, K.; Telting, D.; Boer, H. de

    2012-01-01

    BACKGROUND: Current treatments for hypercalcemia caused by lung cell carcinomas producing parathyroid hormone-related peptide (PTH-rp) have limited efficacy, probably because of their lack of effect on PTH-rp secretion. In this case study we explored the efficacy of the calcimimetic cinacalcet as su

  14. Ectopic PDX-1 Expression Directly Reprograms Human Keratinocytes along Pancreatic Insulin-Producing Cells Fate

    Science.gov (United States)

    Chernichovski, Ellad; Nakar, Odelia; Winkler, Eyal; Mazkereth, Ram; Orenstein, Arie; Bar-Meir, Eran; Ravassard, Philippe; Meivar-Levy, Irit; Ferber, Sarah

    2011-01-01

    Background Cellular differentiation and lineage commitment have previously been considered irreversible processes. However, recent studies have indicated that differentiated adult cells can be reprogrammed to pluripotency and, in some cases, directly into alternate committed lineages. However, although pluripotent cells can be induced in numerous somatic cell sources, it was thought that inducing alternate committed lineages is primarily only possible in cells of developmentally related tissues. Here, we challenge this view and analyze whether direct adult cell reprogramming to alternate committed lineages can cross the boundaries of distinct developmental germ layers. Methodology/Principal Findings We ectopically expressed non-integrating pancreatic differentiation factors in ectoderm-derived human keratinocytes to determine whether these factors could directly induce endoderm-derived pancreatic lineage and β-cell-like function. We found that PDX-1 and to a lesser extent other pancreatic transcription factors, could rapidly and specifically activate pancreatic lineage and β-cell-like functional characteristics in ectoderm-derived human keratinocytes. Human keratinocytes transdifferentiated along the β cell lineage produced processed and secreted insulin in response to elevated glucose concentrations. Using irreversible lineage tracing for KRT-5 promoter activity, we present supporting evidence that insulin-positive cells induced by ectopic PDX-1 expression are generated in ectoderm derived keratinocytes. Conclusions/Significance These findings constitute the first demonstration of human ectoderm cells to endoderm derived pancreatic cells transdifferentiation. The study represents a proof of concept which suggests that transcription factors induced reprogramming is wider and more general developmental process than initially considered. These results expanded the arsenal of adult cells that can be used as a cell source for generating functional endocrine

  15. The Jekyll and Hyde story of IL17-Producing γδT Cells.

    Science.gov (United States)

    Patil, Rushikesh S; Bhat, Sajad A; Dar, Asif A; Chiplunkar, Shubhada V

    2015-01-01

    In comparison to conventional αβT cells, γδT cells are considered as specialized T cells based on their contributions in regulating immune response. γδT cells sense early environmental signals and initiate local immune-surveillance. The development of functional subtypes of γδT cells takes place in the thymus but they also exhibit plasticity in response to the activating signals and cytokines encountered in the extrathymic region. Thymic development of Tγδ1 requires strong TCR, CD27, and Skint-1 signals. However, differentiation of IL17-producing γδT cells (Tγδ17) is independent of Skint-1 or CD27 but requires notch signaling along with IL6 and TGFβ cytokines in the presence of weak TCR signal. In response to cytokines like IL23, IL6, and IL1β, Tγδ17 outshine Th17 cells for early activation and IL17 secretion. Despite expressing similar repertoire of lineage transcriptional factors, cytokines, and chemokine receptors, Tγδ17 cells differ from Th17 in spatial and temporal fashion. There are compelling reasons to consider significant role of Tγδ17 cells in regulating inflammation and thereby disease outcome. Tγδ17 cells regulate mobilization of innate immune cells and induce keratinocytes to secrete anti-microbial peptides thus exhibiting protective functions in anti-microbial immunity. In contrast, dysregulated Tγδ17 cells inhibit Treg cells, exacerbate autoimmunity, and are also known to support carcinogenesis by enhancing angiogenesis. The mechanism associated with this dual behavior of Tγδ17 is not clear. To exploit, Tγδ17 cells for beneficial use requires comprehensive analysis of their biology. Here, we summarize the current understanding on the characteristics, development, and functions of Tγδ17 cells in various pathological scenarios.

  16. BDNF, produced by a TPO-stimulated megakaryocytic cell line, regulates autocrine proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Shogo [Graduate School of Health Sciences, Hokkaido University, Sapporo (Japan); Research Fellow of the Japan Society for the Promotion of Science, Tokyo (Japan); Nagasawa, Ayumi; Masuda, Yuya; Tsunematsu, Tetsuya [Graduate School of Health Sciences, Hokkaido University, Sapporo (Japan); Hayasaka, Koji; Matsuno, Kazuhiko; Shimizu, Chikara [Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo (Japan); Ozaki, Yukio [Department of Clinical and Laboratory Medicine, Faculty of Medicine, University of Yamanashi (Japan); Moriyama, Takanori, E-mail: moriyama@hs.hokuda.ac.jp [Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo (Japan)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer It has been thought that BDNF is not produced in the megakaryocytic lineage. Black-Right-Pointing-Pointer MEG-01 produces BDNF upon TPO stimulation and regulates its proliferation. Black-Right-Pointing-Pointer BDNF accelerates proliferation of MEG-01 in an autocrine manner. Black-Right-Pointing-Pointer BDNF may be an autocrine MEG-CSF, which regulates megakaryopoiesis. -- Abstract: While human platelets release endogenous brain-derived neurotrophic factor (BDNF) upon activation, a previous report on MEG-01, a megakaryocytic cell line, found no trace of BDNF production, and the pathophysiological function of platelet BDNF has remained elusive. In the present study, we demonstrate that MEG-01 produces BDNF in the presence of TPO and that this serves to potentiate cell proliferation. Our in vitro findings suggest that BDNF regulates MEG-01 proliferation in an autocrine manner, and we suggest that BDNF may be a physiological autocrine regulator of megakaryocyte progenitors.

  17. Differentiation of human labia minora dermis-derived fibroblasts into insulin-producing cells

    Science.gov (United States)

    Kim, Bona; Yoon, Byung Sun; Moon, Jai-Hee; Kim, Jonggun; Jun, Eun Kyoung; Lee, Jung Han; Kim, Jun Sung; Baik, Cheong Soon; Kim, Aeree; Whang, Kwang Youn

    2012-01-01

    Recent evidence has suggested that human skin fibroblasts may represent a novel source of therapeutic stem cells. In this study, we report a 3-stage method to induce the differentiation of skin fibroblasts into insulin-producing cells (IPCs). In stage 1, we establish the isolation, expansion and characterization of mesenchymal stem cells from human labia minora dermis-derived fibroblasts (hLMDFs) (stage 1: MSC expansion). hLMDFs express the typical mesenchymal stem cell marker proteins and can differentiate into adipocytes, osteoblasts, chondrocytes or muscle cells. In stage 2, DMEM/F12 serum-free medium with ITS mix (insulin, transferrin, and selenite) is used to induce differentiation of hLMDFs into endoderm-like cells, as determined by the expression of the endoderm markers Sox17, Foxa2, and PDX1 (stage 2: mesenchymal-endoderm transition). In stage 3, cells in the mesenchymal-endoderm transition stage are treated with nicotinamide in order to further differentiate into self-assembled, 3-dimensional islet cell-like clusters that express multiple genes related to pancreatic β-cell development and function (stage 3: IPC). We also found that the transplantation of IPCs can normalize blood glucose levels and rescue glucose homeostasis in streptozotocin-induced diabetic mice. These results indicate that hLMDFs have the capacity to differentiate into functionally competent IPCs and represent a potential cell-based treatment for diabetes mellitus. PMID:22020533

  18. Dendritic cells produce macrophage inflammatory protein-1 gamma, a new member of the CC chemokine family.

    Science.gov (United States)

    Mohamadzadeh, M; Poltorak, A N; Bergstressor, P R; Beutler, B; Takashima, A

    1996-05-01

    Langerhans cells (LC) are skin-specific members of the dendritic cell (DC) family. DC are unique among APC for their capacity to activate immunologically naive T cells, but little is known about their chemotactic recruitment of T cells. We now report that LC produce macrophage inflammatory protein-1 gamma (MIP-1 gamma), a newly identified CC chemokine. MIP-1 gamma mRNA was detected in epidermal cells freshly procured from BALB/c mice, and depletion of I-A+ epidermal cells (i.e., LC) abrogated that expression. MIP-1 gamma mRNA was detected in the XS52 LC-like DC line as well as by 4F7+ splenic DC and granulocyte-macrophage CSF-propagated bone marrow DC. XS52 DC culture supernatants contained 9 and 10.5 kDa immunoreactivities with anti-MIP-1 gamma Abs. We observed in Boyden chamber assays that 1) XS52 DC supernatant (added to the lower chambers) induced significant migration by splenic T cells; 2) this migration was blocked by the addition of anti-MIP-1 gamma in the lower chambers or by rMIP-1 gamma in the upper chambers; and 3) comparable migration occurred in both CD4+ and CD8+ T cells and in both activated and nonactivated T cells. We conclude that mouse DC (including LC) have the capacity to elaborate the novel CC chemokine MIP-1 gamma, suggesting the active participation of DC in recruiting T cells before activation.

  19. Skin-infiltrating, interleukin-22-producing T cells differentiate pediatric psoriasis from adult psoriasis.

    Science.gov (United States)

    Cordoro, Kelly M; Hitraya-Low, Maria; Taravati, Keyon; Sandoval, Priscila Munoz; Kim, Esther; Sugarman, Jeffrey; Pauli, Mariela L; Liao, Wilson; Rosenblum, Michael D

    2017-09-01

    Evidence from adult psoriasis studies implicates an imbalance between regulatory and effector T cells, particularly TH-17-producing T cells, in the pathogenesis of psoriasis. Little is known about the immunopathology of psoriasis in children. We sought to functionally characterize the inflammatory cell profiles of psoriatic plaques from pediatric patients and compare them with healthy, age-matched controls and adult psoriasis patients. Skin samples from pediatric psoriasis patients and healthy controls were analyzed by multiparameter flow cytometry to determine the dominant immune cell subsets present and cytokines produced. Lesional tissue from pediatric psoriasis patients had significantly increased interleukin (IL) 22 derived from CD4(+) and CD8(+) cells compared with the tissues from healthy pediatric controls and adult psoriasis patients. Tissue from pediatric psoriasis patients had significantly less elevation of IL-17 derived from CD4(+) and CD8(+) cells compared with the tissue from adult psoriasis patients. In contrast with the lesions from adult patients, lesional skin in pediatric patients with psoriasis did not have increases in regulatory T cells. This is a pilot study, thus the sample size is small. Significant differences in IL-17 and IL-22 expression were observed in the pediatric psoriasis patients compared with pediatric healthy controls and adult psoriasis patients. IL-22 might be relevant in the pathogenesis of pediatric psoriasis and represents a potential treatment target unique to pediatric psoriasis. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  20. Isolation and characterization of cytotoxic effector cells and antibody producing cells from human intestine.

    Science.gov (United States)

    MacDermott, R P

    1985-01-01

    We have examined the ability of intestinal and peripheral blood mononuclear cells isolated from patients with inflammatory bowel disease to mediate killing against cell line targets in spontaneous, antibody-dependent, lectin-induced, and interferon-induced cell-mediated cytotoxicity assays, as well as responsiveness in the allogeneic mixed leukocyte reaction, and effector capabilities in cell-mediated lympholysis. IMC were poor mediators of spontaneous or antibody-dependent cellular cytotoxicity with cell line cells as targets (in comparison to normal PBMC, but were capable of killing antibody coated chicken red blood cells. Although IMC were capable of responding to allogeneic cell surface antigens in the mixed leukocyte reaction, they did not exhibit effector function in cell-mediated lympholysis. Mitogenic lectins induced cell-mediated cytotoxicity by isolated intestinal mononuclear cells from controls and patients. HFIF induces cytotoxicity by control but not inflammatory bowel disease intestinal cells. Pokeweed mitogen was the lectin which induced the greatest amount of killing against human cell line targets. We therefore speculate that exogenous agents, or endogenous factors released during viral infection, could play a role in inducing cell mediated cytotoxic damage to the intestine in inflammatory bowel disease patients. In addition, the functional differences between IMC and PBMC indicate that intestinal MNC may have unique cell capabilities which must be better understood prior to the delineation of immunopathologic events in solid organ tissues. We have also examined the secretion of IgA, IgM, and IgG by isolated human IMC, human bone marrow MNC from rib specimens, and PBMC from patients with CD, UC, SLE, or Henoch-Schoenlein purpura (HSP). Control IMC exhibited high spontaneous secretion of IgA, while intestinal MNC from UC and CD patients exhibited only modest increases in IgA secretion. PBMC from patients with CD, UC, SLE, or HSP exhibited markedly

  1. Gas-liquid interfacial plasmas producing reactive species for cell membrane permeabilization

    Science.gov (United States)

    Kaneko, Toshiro; Sasaki, Shota; Takashima, Keisuke; Kanzaki, Makoto

    2017-01-01

    Gas-liquid interfacial atmospheric-pressure plasma jets (GLI-APPJ) are used medically for plasma-induced cell-membrane permeabilization. In an attempt to identify the dominant factors induced by GLI-APPJ responsible for enhancing cell-membrane permeability, the concentration and distribution of plasma-produced reactive species in the gas and liquid phase regions are measured. These reactive species are classified in terms of their life-span: long-lived (e.g., H2O2), short-lived (e.g., O2•−), and extremely-short-lived (e.g., •OH). The concentration of plasma-produced •OHaq in the liquid phase region decreases with an increase in solution thickness (plasma-induced cell-membrane permeabilization is found to decay markedly as the thickness of the solution increases. Furthermore, the horizontally center-localized distribution of •OHaq, resulting from the center-peaked distribution of •OH in the gas phase region, corresponds with the distribution of the permeabilized cells upon APPJ irradiation, whereas the overall plasma-produced oxidizing species such as H2O2aq in solution exhibit a doughnut-shaped horizontal distribution. These results suggest that •OHaq is likely one of the dominant factors responsible for plasma-induced cell-membrane permeabilization. PMID:28163376

  2. Inhibition of osteoclastogenesis by osteoblast-like cells genetically engineered to produce interleukin-10.

    Science.gov (United States)

    Fujioka, Kazuki; Kishida, Tsunao; Ejima, Akika; Yamamoto, Kenta; Fujii, Wataru; Murakami, Ken; Seno, Takahiro; Yamamoto, Aihiro; Kohno, Masataka; Oda, Ryo; Yamamoto, Toshiro; Fujiwara, Hiroyoshi; Kawahito, Yutaka; Mazda, Osam

    2015-01-16

    Bone destruction at inflamed joints is an important complication associated with rheumatoid arthritis (RA). Interleukin-10 (IL-10) may suppress not only inflammation but also induction of osteoclasts that play key roles in the bone destruction. If IL-10-producing osteoblast-like cells are induced from patient somatic cells and transplanted back into the destructive bone lesion, such therapy may promote bone remodeling by the cooperative effects of IL-10 and osteoblasts. We transduced mouse fibroblasts with genes for IL-10 and Runx2 that is a crucial transcription factor for osteoblast differentiation. The IL-10-producing induced osteoblast-like cells (IL-10-iOBs) strongly expressed osteoblast-specific genes and massively produced bone matrix that were mineralized by calcium phosphate in vitro and in vivo. Culture supernatant of IL-10-iOBs significantly suppressed induction of osteoclast from RANKL-stimulated Raw264.7 cells as well as LPS-induced production of inflammatory cytokine by macrophages. The IL-10-iOBs may be applicable to novel cell-based therapy against bone destruction associated with RA. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Human umbilical cord mesenchymal stem cells derived from Wharton's jelly differentiate into insulin-producing cells in vitro

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-wu; LIN Li-min; HE Hong-yan; YOU Fang; LI Wei-zhong; HUANG Tian-hua; MA Gui-xia; MA Lian

    2011-01-01

    Background Islet transplantation is an effective way of reversing type Ⅰ diabetes. However, islet transplantation is hampered by issues such as immune rejection and shortage of donor islets. Mesenchymal stem cells can differentiate into insulin-producing cells. However, the potential of human umbilical cord mesenchymal stem cells (huMSCs) to become insulin-producing cells remains undetermined.Methods We isolated and induced cultured huMSCs under islet cell culture conditions. The response of huMSCs were monitored under an inverted phase contrast microscope. Immunocytochemical and immunofluorescence staining methods were used to measure insulin and glucagon protein levels. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect gene expression of human insulin and PDX-1. Dithizone-staining was employed to determine the zinc contents in huMSCs. Insulin secretion was also evaluated through radioimmunoassay.Results HuMSCs induced by nicotinamide and β-mercaptoethanol or by neurogenic differentiation 1 gene (NeuroD1)transfection gradually changed morphology from typically elongated fibroblast-shaped cells to round cells. They had a tendency to form clusters. Immunocytochemical studies showed positive expression of human insulin and glucagon in these cells in response to induction. RT-PCR experiments found that huMSCs expressed insulin and PDX-1 genes following induction and dithizone stained the cytoplasm of huMSCs a brownish red color after induction. Insulin secretion in induced huMSCs was significantly elevated compared with the control group (t=6.183, P<0.05).Conclusions HuMSCs are able to differentiate into insulin-producing cells in vitro. The potential use of huMSCs in βcell replacement therapy of diabetes needs to be studied further.

  4. Shale gas produced water treatment using innovative microbial capacitive desalination cell.

    Science.gov (United States)

    Stoll, Zachary A; Forrestal, Casey; Ren, Zhiyong Jason; Xu, Pei

    2015-01-01

    The rapid development of unconventional oil and gas production has generated large amounts of wastewater for disposal, raising significant environmental and public health concerns. Treatment and beneficial use of produced water presents many challenges due to its high concentrations of petroleum hydrocarbons and salinity. The objectives of this study were to investigate the feasibility of treating actual shale gas produced water using a bioelectrochemical system integrated with capacitive deionization-a microbial capacitive desalination cell (MCDC). Microbial degradation of organic compounds in the anode generated an electric potential that drove the desalination of produced water. Sorption and biodegradation resulted in a combined organic removal rate of 6.4 mg dissolved organic carbon per hour in the reactor, and the MCDC removed 36 mg salt per gram of carbon electrode per hour from produced water. This study is a proof-of-concept that the MCDC can be used to combine organic degradation with desalination of contaminated water without external energy input.

  5. Envisioning Agricultural Sustainability from Field to Plate: Comparing Producer and Consumer Attitudes and Practices toward "Environmentally Friendly" Food and Farming in Washington State, USA

    Science.gov (United States)

    Selfa, Theresa; Jussaume, Raymond A., Jr.; Winter, Michael

    2008-01-01

    A substantial body of sociological research has examined the relationship between farmers' environmental attitudes and their conservation behaviors, but little research has compared the attitudes of producers and consumers toward the environment with their behaviors or practices in support of sustainable agri-food systems. This paper addresses…

  6. Envisioning Agricultural Sustainability from Field to Plate: Comparing Producer and Consumer Attitudes and Practices toward "Environmentally Friendly" Food and Farming in Washington State, USA

    Science.gov (United States)

    Selfa, Theresa; Jussaume, Raymond A., Jr.; Winter, Michael

    2008-01-01

    A substantial body of sociological research has examined the relationship between farmers' environmental attitudes and their conservation behaviors, but little research has compared the attitudes of producers and consumers toward the environment with their behaviors or practices in support of sustainable agri-food systems. This paper addresses…

  7. Anticorrosion Coating of Carbon Nanotube/Polytetrafluoroethylene Composite Film on the Stainless Steel Bipolar Plate for Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Show

    2013-01-01

    Full Text Available Composite film of carbon nanotube (CNT and polytetrafluoroethylene (PTFE was formed from dispersion fluids of CNT and PTFE. The composite film showed high electrical conductivity in the range of 0.1–13 S/cm and hydrophobic nature. This composite film was applied to stainless steel (SS bipolar plates of the proton exchange membrane fuel cell (PEMFC as anticorrosion film. This coating decreased the contact resistance between the surface of the bipolar plate and the membrane electrode assembly (MEA of the PEMFC. The output power of the fuel cell is increased by 1.6 times because the decrease in the contact resistance decreases the series resistance of the PEMFC. Moreover, the coating of this composite film protects the bipolar plate from the surface corrosion.

  8. The regulation of function, growth and survival of GLP-1-producing L-cells

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Holst, Jens Juul; Kappe, Camilla

    2016-01-01

    absorption and disposal, as well as cell proliferation and survival. In Type 2 Diabetes (T2D) reduced plasma levels of GLP-1 have been observed, and plasma levels of GLP-1, as well as reduced numbers of GLP-1 producing cells, have been correlated to obesity and insulin resistance. Increasing endogenous......Glucagon-like peptide-1 (GLP-1) is a peptide hormone, released from intestinal L-cells in response to hormonal, neural and nutrient stimuli. In addition to potentiation of meal-stimulated insulin secretion, GLP-1 signalling exerts numerous pleiotropic effects on various tissues, regulating energy...... secretion of GLP-1 by selective targeting of the molecular mechanisms regulating secretion from the L-cell has been the focus of much recent research. An additional and promising strategy for enhancing endogenous secretion may be to increase the L-cell mass in the intestinal epithelium, but the mechanisms...

  9. B Cell-Activating Factor Regulates Different Aspects of B Cell Functionality and Is Produced by a Subset of Splenic B Cells in Teleost Fish.

    Science.gov (United States)

    Tafalla, Carolina; González, Lucia; Castro, Rosario; Granja, Aitor G

    2017-01-01

    In mammals, B cell functionality is greatly influenced by cytokines released by innate cells, such as macrophages or dendritic cells, upon the early recognition of common pathogen patterns through invariant receptors. B cell-activating factor (BAFF) is one of these innate B cell-helper signals and plays a key role in the survival and differentiation of B cells. Although, evolutionarily, teleost fish constitute the first animal group in which adaptive immunity based on Ig receptors is present, fish still rely greatly on innate responses. In this context, we hypothesized that BAFF would play a key role in the control of B cell responses in fish. Supporting this, our results show that teleost BAFF recapitulates mammalian BAFF stimulating actions on B cells, upregulating the expression of membrane MHC II, improving the survival of fish naïve B cells and antibody-secreting cells, and increasing the secretion of IgM. Surprisingly, we also demonstrate that BAFF is not only produced in fish by myeloid cells but is also produced by a subset of splenic B cells. Thus, if this B cell-produced BAFF proves to be actively regulating this same B cell subset, our findings point to an ancient mechanism to control B cell differentiation and survival in lower vertebrates, which has been silenced in mammals in physiological conditions, but reemerges under pathological conditions, such as B cell lymphomas and autoimmune diseases.

  10. Human amnion epithelial cells can be induced to differentiate into functional insulin-producing cells

    Institute of Scientific and Technical Information of China (English)

    Yanan Hou; Qin Huang; Tianjin Liu; Lihe Guo

    2008-01-01

    Pancreatic islet transplantation has demonstrated that long-term insulin independence may be achieved in patients suffering from diabetes mellitus type 1. However, limited availability of islet tissue means that new sources of insulinproducing cells that are responsive to glucose are required. Here, we show that human amnion epithelial cells (HAEC) can be induced to differentiate into functional insulinproducing cells in vitro. After induction of differentiation, HAEC expressed multiple pancreatic --cell genes, including insulin, pancreas duodenum homeobox-1, paired box gene 6,NK2 transcription factor-related locus 2, Islet 1, glucokinase,and glucose transporter-2, and released C-peptide in a glucose-regulated manner in response to other extracellular stimulations. The transplantation of induced HAEC into streptozotocin-induced diabetic C57 mice reversed hyperglycemia, restored body weight, and maintained euglycemia for 30 d. These findings indicated that HAEC may be a new source for cell replacement therapy in type 1 diabetes.

  11. High numbers of IL-2-producing CD8+ T cells during viral infection: correlation with stable memory development

    DEFF Research Database (Denmark)

    Kristensen, Nanna Ny; Christensen, Jan Pravsgaard; Thomsen, Allan Randrup

    2002-01-01

    that IL-2-producing cells appear slightly delayed compared with the majority of IFN-gamma producing cells, and the relative frequency of the IL-2-producing subset increases with transition into the memory phase. In contrast to acute immunizing infection, few IL-2-producing cells are generated during......Using infections with lymphocytic choriomeningitis virus (LCMV) and vesicular stomatitis virus in mice as model systems, we have investigated the ability of antigen-primed CD8+ T cells generated in the context of viral infections to produce IL-2. Our results indicate that acute immunizing infection...

  12. Regeneration of insulin-producing pancreatic cells using a volatile bioactive compound and human teeth.

    Science.gov (United States)

    Okada, Mio; Imai, Toshio; Yaegaki, Ken; Ishkitiev, Nikolay; Tanaka, Tomoko

    2014-10-30

    Transplantation of insulin (INS)-secreting cells differentiated in vitro from stem cells promises a safer and easier treatment of severe diabetes mellitus. A volatile bioactive compound, hydrogen sulfide (H2S), promotes cell differentiation; human tooth-pulp stem cells undergo hepatic differentiation. The aim of this study is to develop a novel protocol using H2S to enhance pancreatic differentiation from the CD117(+) cell fraction of human tooth pulp. During the differentiation, the cells were exposed to 0.1 ng ml(-1) H2S. Immunocytochemistry, RT-PCR, determination of INS c-peptide content and flow cytometry of pancreatically related markers were carried out. Expression of WNT and the PI3K/AKT signaling pathway were also determined by PCR array. After differentiation, INS, glucagon (GCG), somatostatin (SST) and pancreatic polypeptide (PPY) were positive when examined by immunofluorescence. INS and GCG were also determined flow-cytometrically. Only the cells expressing INS increased after H2S exposure. The number of cells expressing GCG was significantly decreased. Genes involved in canonical WNT and the WNT/calcium pathways were highly expressed after H2S exposure. H2S accelerated INS synthesis and secretion by regenerated INS-producing cells from human teeth. All signaling pathway functions of the PI3K-AKT pathway were extremely activated by H2S exposure. The matured INS-producing cells originating in human teeth were increased by H2S in order to control blood-glucose level.

  13. Subcultured odontogenic epithelial cells in combination with dental mesenchymal cells produce enamel-dentin-like complex structures.

    Science.gov (United States)

    Honda, M J; Shinohara, Y; Hata, K I; Ueda, M

    2007-01-01

    We showed in a previous study that odontogenic epithelial cells can be selectively cultured from the enamel organ in serum-free medium and expanded using feeder layers of 3T3-J2 cells. The subcultured odontogenic epithelial cells retain the capacity for ameloblast-related gene expression, as shown by semiquantitative RT-PCR. The purpose of the present study was to evaluate the potential of subcultured odontogenic epithelial cells to form tooth structures in cell-polymer constructs maintained in vivo. Enamel organs from 6-month-old porcine third molars were dissociated into single odontogenic epithelial cells and subcultured on feeder layers of 3T3-J2 cells. Amelogenin expression was detected in the subcultured odontogenic epithelial cells by immunostaining and Western blotting. The subcultured odontogenic epithelial cells were seeded onto collagen sponge scaffolds in combination with fresh dental mesenchymal cells, and transplanted into athymic rats. After 4 weeks, enamel-dentin-like complex structures were present in the implanted constructs. These results show that our culture system produced differentiating ameloblast-like cells that were able to secrete amelogenin proteins and form enamel-like tissues in vivo. This application of the subculturing technique provides a foundation for further tooth-tissue engineering and for improving our understanding of ameloblast biology.

  14. Continuous Collection of Adeno-Associated Virus from Producer Cell Medium Significantly Increases Total Viral Yield.

    Science.gov (United States)

    Benskey, Matthew J; Sandoval, Ivette M; Manfredsson, Fredric P

    2016-02-01

    The ability to efficiently produce large amounts of high-titer recombinant adeno-associated virus (AAV) is a prerequisite to the continued success of AAV as a gene therapy tool targeted toward large-animal preclinical studies or human clinical therapeutics. Current manufacturing procedures necessitate laborious and time-consuming purification procedures to obtain AAV particles of sufficient titer and purity for these demanding biomedical applications. The finding that AAV can be harvested and purified from producer cell medium may represent an efficient alternative to purifying AAV from cellular lysates. Here we sought to determine the maximum duration of time, and frequency within which AAV can be harvested from producer cell medium, in order to maximize the yield obtained from a single transfection preparation. Human embryonic kidney 293T cells were transfected with polyethylenimine to produce AAV2/5 expressing green fluorescent protein (GFP), and cellular medium was harvested every 2 days until a maximum duration of 19 days posttransfection. AAV2/5-GFP was released into producer cell medium at a steady state until 7 days posttransfection, at which time titers dropped dramatically. Harvesting medium every two days resulted in the maximum yield of AAV from a single preparation, and the cumulative yield of AAV harvested from the producer cell medium was 4-fold higher than the yield obtained from a traditional purification of AAV from cellular lysates. The AAV2/5 harvested from medium within the 7-day collection time-course mediated high levels of transduction in vivo, comparable to AAV2/5 harvested from cellular lysates. AAV purified from cell lysates showed increasing amounts of empty particles at 5 and 7 days posttransfection, whereas AAV purified from cell medium did not show an increase in the amount of empty particles throughout the 7-day time course. Finally, we extended these findings to AAV2/9, demonstrating that a comparable ratio of AAV2/9 particles are

  15. Improved cytotoxic effects of Salmonella-producing cytosine deaminase in tumour cells

    Science.gov (United States)

    Mesa-Pereira, Beatriz; Medina, Carlos; Camacho, Eva María; Flores, Amando; Santero, Eduardo

    2015-01-01

    In order to increase the cytotoxic activity of a Salmonella strain carrying a salicylate-inducible expression system that controls cytosine deaminase production, we have modified both, the vector and the producer bacterium. First, the translation rates of the expression module containing the Escherichia coli codA gene cloned under the control of the Pm promoter have been improved by using the T7 phage gene 10 ribosome binding site sequence and replacing the original GUG start codon by AUG. Second, to increase the time span in which cytosine deaminase may be produced by the bacteria in the presence of 5-fluorocytosine, a 5-fluorouracyl resistant Salmonella strain has been constructed by deleting its upp gene sequence. This new Salmonella strain shows increased cytosine deaminase activity and, after infecting tumour cell cultures, increased cytotoxic and bystander effects under standard induction conditions. In addition, we have generated a purD mutation in the producer strain to control its intracellular proliferation by the presence of adenine and avoid the intrinsic Salmonella cell death induction. This strategy allows the analysis and comparison of the cytotoxic effects of cytosine deaminase produced by different Salmonella strains in tumour cell cultures. PMID:25227763

  16. CD4(+) T cells producing interleukin (IL)-17, IL-22 and interferon-? are major effector T cells in nickel allergy

    DEFF Research Database (Denmark)

    Dyring Andersen, Beatrice; Skov, Lone; Løvendorf, Marianne B

    2013-01-01

    Background It has been suggested that interleukin (IL)-17 and IL-22 play important roles in the elicitation of human allergic contact dermatitis; however, the frequencies of T cell subtypes producing IL-17 and IL-22 in human allergic contact dermatitis are unknown. Objectives To determine...

  17. Establishment of a mouse Sertoli cell line producing rat androgen-binding protein (ABP).

    Science.gov (United States)

    Ducray, A; Bloquel, M; Hess, K; Hammond, G L; Gérard, H; Gérard, A

    1998-01-01

    The ultimate goal of this study was to compare the fate of rat testicular germ cells cocultured with mouse Sertoli cells that either do or do not produce rat androgen-binding protein (ABP). As a first step, we stably transfected a rat ABP expression construct into an immortalized mouse Sertoli cell line (TM4), which does not produce ABP when growing on plastic without hormones. The transfection of the pRc/CMV- rat ABP cDNA expression vector containing a neomycin resistance gene was made by either the liposome method (Dotap) or by polyethyleneimine transfection (PEI) into TM4 cell cultures. Neomycin-resistant clones were selected by adding Geneticin to the culture medium for 3 weeks. Analysis of over 25 clones revealed the presence of recombinant rat ABP when cell extracts and culture media were probed with a rabbit polyclonal antibody raised against rat testicular ABP, indicating the translation and secretion of a protein similar to rat testicular ABP. Transfected TM4 cells maintain the secretion of rat ABP for more than 40 days, with immunopositive rat ABP localized within cytoplasmic granules in the Golgi region and along cytoplasmic processes in TM4 transfected with either vector. Electron microscopic study revealed a higher development of cytoplasmic organelles involved in protein secretion.

  18. Visualization of sialic acid produced on bacterial cell surfaces by lectin staining.

    Science.gov (United States)

    Kajiwara, Hitomi; Toda, Munetoyo; Mine, Toshiki; Nakada, Hiroshi; Wariishi, Hiroyuki; Yamamoto, Takeshi

    2010-01-01

    Oligosaccharides containing N-acetylneuraminic acid on the cell surface of some pathogenic bacteria are important for host-microbe interactions. N-acetylneuraminic acid (Neu5Ac) plays a major role in the pathogenicity of bacterial pathogens. For example, cell surface sialyloligosaccharide moieties of the human pathogen Haemophilus influenzae are involved in virulence and adhesion to host cells. In this study, we have established a method of visualizing Neu5Ac linked to a glycoconjugate on the bacterial cell surface based on lectin staining. Photobacterium damselae strain JT0160, known to produce a-2,6-sialyltransferase, was revealed to possess Neu5Ac by HPLC. Using the strain, a strong Sambucus sieboldiana lectin-binding signal was detected. The bacteria producing α-2,6-sialyltransferases could be divided into two groups: those with a lot of α-2,6-linked Neu5Ac on the cell surface and those with a little. In the present study, we developed a useful method for evaluating the relationship between Neu5Ac expression on the cell surface and the degree of virulence of marine bacteria.

  19. Differences in physico-mechanical behaviors of resol(e) and novolac type phenolic resin based composite bipolar plate for proton exchange membrane (PEM) fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Kakati, Biraj Kumar [Department of Chemical Engineering, Indian Institute of Technology Guwahati, North Guwahati, PIN 781 039, Dist. Kamrup (Assam) (India); Deka, Dhanapati [Department of Energy, Tezpur University, Tezpur 784 028, Dist. Sonitpur (Assam) (India)

    2007-09-15

    Composite bipolar plates for Proton Exchange Membrane Fuel Cell (PEMFC) are prepared by compression molding technique using polymer as binder and graphite as electric filler material with some other reinforcements. Study on the effect of resole and novolac type phenolic resin on the properties of composite bipolar plate, such as bulk density, porosity, bulk conductivity, hardness, flexural strength, etc. shows that both of the resin shows different physico-mechanical properties. Moreover, single cell performance analysis also shows variation for resole and novolac based composites. A novel concept of triple continuous structure to provide graphite polymer blends with high electrical conductivity, high shore hardness, high flexural strength, less porosity and low density has been proposed and study on the effect of different types of phenolic resin on the properties and performance of bipolar plate reveals that novolac type powdered phenolic resin gives better mechanical properties than resole type phenolic resin. However, resole type phenolic resin compound has slightly higher electrical conductivity due to more number of polar -OH group presents on its cured form. But due to the less porosity and higher mechanical strength, bipolar plates with novolac type phenolic resin gives better performance in I-V analysis than bipolar plates with resole type phenolic resin. (author)

  20. Inaccurate DNA synthesis in cell extracts of yeast producing active human DNA polymerase iota.

    Directory of Open Access Journals (Sweden)

    Alena V Makarova

    Full Text Available Mammalian Pol ι has an unusual combination of properties: it is stimulated by Mn(2+ ions, can bypass some DNA lesions and misincorporates "G" opposite template "T" more frequently than incorporates the correct "A." We recently proposed a method of detection of Pol ι activity in animal cell extracts, based on primer extension opposite the template T with a high concentration of only two nucleotides, dGTP and dATP (incorporation of "G" versus "A" method of Gening, abbreviated as "misGvA". We provide unambiguous proof of the "misGvA" approach concept and extend the applicability of the method for the studies of variants of Pol ι in the yeast model system with different cation cofactors. We produced human Pol ι in baker's yeast, which do not have a POLI ortholog. The "misGvA" activity is absent in cell extracts containing an empty vector, or producing catalytically dead Pol ι, or Pol ι lacking exon 2, but is robust in the strain producing wild-type Pol ι or its catalytic core, or protein with the active center L62I mutant. The signature pattern of primer extension products resulting from inaccurate DNA synthesis by extracts of cells producing either Pol ι or human Pol η is different. The DNA sequence of the template is critical for the detection of the infidelity of DNA synthesis attributed to DNA Pol ι. The primer/template and composition of the exogenous DNA precursor pool can be adapted to monitor replication fidelity in cell extracts expressing various error-prone Pols or mutator variants of accurate Pols. Finally, we demonstrate that the mutation rates in yeast strains producing human DNA Pols ι and η are not elevated over the control strain, despite highly inaccurate DNA synthesis by their extracts.

  1. Role of thyrotropin-releasing hormone in prolactin-producing cell models.

    Science.gov (United States)

    Kanasaki, Haruhiko; Oride, Aki; Mijiddorj, Tselmeg; Kyo, Satoru

    2015-12-01

    Thyrotropin-releasing hormone (TRH) is a hypothalamic hypophysiotropic neuropeptide that was named for its ability to stimulate the release of thyroid-stimulating hormone in mammals. It later became apparent that it exerts a number of species-dependent hypophysiotropic activities that regulate other pituitary hormones. TRH also regulates the synthesis and release of prolactin, although whether it is a physiological regulator of prolactin that remains unclear. Occupation of the Gq protein-coupled TRH receptor in the prolactin-producing lactotroph increases the turnover of inositol, which in turn activates the protein kinase C pathway and the release of Ca(2+) from storage sites. TRH-induced signaling events also include the activation of extracellular signal-regulated kinase (ERK) and induction of MAP kinase phosphatase, an inactivator of activated ERK. TRH stimulates prolactin synthesis through the activation of ERK, whereas prolactin release occurs via elevation of intracellular Ca(2+). We have been investigating the role of TRH in a pituitary prolactin-producing cell model. Rat pituitary somatolactotroph GH3 cells, which produce and release both prolactin and growth hormone (GH), are widely used as a model for the study of prolactin- and GH-secreting cells. In this review, we describe the general action of TRH as a hypophysiotropic factor in vertebrates and focus on the role of TRH in prolactin synthesis using GH3 cells.

  2. Biocompatibility Analyses of Al₂O₃-Treated Titanium Plates Tested with Osteocyte and Fibroblast Cell Lines.

    Science.gov (United States)

    Smargiassi, Alberto; Bertacchini, Jessika; Checchi, Marta; Cavani, Francesco; Ferretti, Marzia; Palumbo, Carla

    2017-06-16

    Osseointegration of a titanium implant is still an issue in dental/orthopedic implants durable over time. The good integration of these implants is mainly due to their surface and topography. We obtained an innovative titanium surface by shooting different-in-size particles of Al₂O₃ against the titanium scaffolds which seems to be ideal for bone integration. To corroborate that, we used two different cell lines: MLO-Y4 (murine osteocytes) and 293 (human fibroblasts) and tested the titanium scaffolds untreated and treated (i.e., Al₂O₃ shot-peened titanium surfaces). Distribution, density, and expression of adhesion molecules (fibronectin and vitronectin) were evaluated under scanning electron microscope (SEM) and confocal microscope (CM). DAPI and fluorochrome-conjugated antibodies were used to highlight nuclei, fibronectin, and vitronectin, under CM; cell distribution was analyzed after gold-palladium sputtering of samples by SEM. The engineered biomaterial surfaces showed under SEM irregular morphology displaying variously-shaped spicules. Both SEM and CM observations showed better outcome in terms of cell adhesion and distribution in treated titanium surfaces with respect to the untreated ones. The results obtained clearly showed that this kind of surface-treated titanium, used to manufacture devices for dental implantology: (i) is very suitable for cell colonization, essential prerequisite for the best osseointegration, and (ii) represents an excellent solution for the development of further engineered implants with the target to obtain recovery of stable dental function over time.

  3. Microtubule-associated protein65 is essential for maintenance of Phragmoplast bipolarity and formation of the cell plate in Physcomitrella patens

    NARCIS (Netherlands)

    Kosetsu, K.; Keijzer, de J.; Janson, M.E.; Goshima, G.

    2013-01-01

    The phragmoplast, a plant-specific apparatus that mediates cytokinesis, mainly consists of microtubules (MTs) arranged in a bipolar fashion, such that their plus ends interdigitate at the equator. Membrane vesicles are thought to move along the MTs toward the equator and fuse to form the cell plate.

  4. Plasmablasts as migratory IgG-producing cells in the pathogenesis of neuromyelitis optica.

    Science.gov (United States)

    Chihara, Norio; Aranami, Toshimasa; Oki, Shinji; Matsuoka, Takako; Nakamura, Masakazu; Kishida, Hitaru; Yokoyama, Kazumasa; Kuroiwa, Yoshiyuki; Hattori, Nobutaka; Okamoto, Tomoko; Murata, Miho; Toda, Tatsushi; Miyake, Sachiko; Yamamura, Takashi

    2013-01-01

    Neuromyelitis optica (NMO) is an inflammatory disease characterized by recurrent attacks of optic neuritis and myelitis. It is generally accepted that autoantibodies against aquaporin 4 water channel protein play a pathogenic role in neuromyelitis optica. We have recently reported that plasmablasts are increased in the peripheral blood of this autoimmune disease, and are capable of producing autoantibodies against aquaporin 4. Here, we demonstrate that CD138(+)HLA-DR(+) plasmablasts, a subset of IgG-producing cells, are increased in the peripheral blood and are enriched among the cerebrospinal fluid (CSF) lymphocytes during the relapse of neuromyelitis optica. Notably, these CD138(+)HLA-DR(+) plasmablasts overexpress CXCR3, whose ligands are present in the cerebrospinal fluid during the relapse of neuromyelitis optica. These results led us to speculate that plasmablasts producing anti-aquaporin 4 autoantibodies might traffic toward the central nervous system (CNS). Furthermore, we performed single-cell sorting of plasmablasts from peripheral blood and CSF samples from NMO and sequenced the complementarity-determining regions (CDRs) of the IgG heavy chain expressed by the sorted plasmablast clones. There were high frequencies of mutations in the CDRs compared with framework regions, indicating that these plasmablast clones would represent a post-germinal center B-cell lineage. Consistent with the preceding results, the plasmablast clones from the peripheral blood shared the same CDR sequences with the clones from the CSF. These results indicate that IgG-producing plasmablasts, which are guided by helper T-cells, may migrate from the peripheral blood preferentially to the CSF. Since migratory plasmablasts could be involved in the inflammatory pathology of NMO, the B-cell subset and their migration might be an attractive therapeutic target.

  5. Plasmablasts as migratory IgG-producing cells in the pathogenesis of neuromyelitis optica.

    Directory of Open Access Journals (Sweden)

    Norio Chihara

    Full Text Available Neuromyelitis optica (NMO is an inflammatory disease characterized by recurrent attacks of optic neuritis and myelitis. It is generally accepted that autoantibodies against aquaporin 4 water channel protein play a pathogenic role in neuromyelitis optica. We have recently reported that plasmablasts are increased in the peripheral blood of this autoimmune disease, and are capable of producing autoantibodies against aquaporin 4. Here, we demonstrate that CD138(+HLA-DR(+ plasmablasts, a subset of IgG-producing cells, are increased in the peripheral blood and are enriched among the cerebrospinal fluid (CSF lymphocytes during the relapse of neuromyelitis optica. Notably, these CD138(+HLA-DR(+ plasmablasts overexpress CXCR3, whose ligands are present in the cerebrospinal fluid during the relapse of neuromyelitis optica. These results led us to speculate that plasmablasts producing anti-aquaporin 4 autoantibodies might traffic toward the central nervous system (CNS. Furthermore, we performed single-cell sorting of plasmablasts from peripheral blood and CSF samples from NMO and sequenced the complementarity-determining regions (CDRs of the IgG heavy chain expressed by the sorted plasmablast clones. There were high frequencies of mutations in the CDRs compared with framework regions, indicating that these plasmablast clones would represent a post-germinal center B-cell lineage. Consistent with the preceding results, the plasmablast clones from the peripheral blood shared the same CDR sequences with the clones from the CSF. These results indicate that IgG-producing plasmablasts, which are guided by helper T-cells, may migrate from the peripheral blood preferentially to the CSF. Since migratory plasmablasts could be involved in the inflammatory pathology of NMO, the B-cell subset and their migration might be an attractive therapeutic target.

  6. Differentiation of Human Mesenchymal Stem Cells into Insulin Producing Cells by Using A Lentiviral Vector Carrying PDX1

    Directory of Open Access Journals (Sweden)

    Amir Allahverdi

    2015-07-01

    Full Text Available Objective: Type I diabetes is an immunologically-mediated devastation of insulin producing cells (IPCs in the pancreatic islet. Stem cells that produce β-cells are a new promising tool. Adult stem cells such as mesenchymal stem cells (MSCs are self renewing multi potent cells showing capabilities to differentiate into ectodermal, mesodermal and endodermal tissues. Pancreatic and duodenal homeobox factor 1 (PDX1 is a master regulator gene required for embryonic development of the pancreas and is crucial for normal pancreatic islets activities in adults. Materials and Methods: We induced the over-expression of the PDX1 gene in human bone marrow MSCs (BM-MSCs by Lenti-PDX1 in order to generate IPCs. Next, we examine the ability of the cells by measuring insulin/c-peptide production and INSULIN and PDX1 gene expressions. Results: After transduction, MSCs changed their morphology at day 5 and gradually differentiated into IPCs. INSULIN and PDX1 expressions were confirmed by real time polymerase chain reaction (RT-PCR and immunostaining. IPC secreted insulin and C-peptide in the media that contained different glucose concentrations. Conclusion: MSCs differentiated into IPCs by genetic manipulation. Our result showed that lentiviral vectors could deliver PDX1 gene to MSCs and induce pancreatic differentiation.

  7. Primary B-cell deficiencies reveal a link between human IL-17-producing CD4 T-cell homeostasis and B-cell differentiation.

    Directory of Open Access Journals (Sweden)

    Rita R Barbosa

    Full Text Available IL-17 is a pro-inflammatory cytokine implicated in autoimmune and inflammatory conditions. The development/survival of IL-17-producing CD4 T cells (Th17 share critical cues with B-cell differentiation and the circulating follicular T helper subset was recently shown to be enriched in Th17 cells able to help B-cell differentiation. We investigated a putative link between Th17-cell homeostasis and B cells by studying the Th17-cell compartment in primary B-cell immunodeficiencies. Common Variable Immunodeficiency Disorders (CVID, defined by defects in B-cell differentiation into plasma and memory B cells, are frequently associated with autoimmune and inflammatory manifestations but we found no relationship between these and Th17-cell frequency. In fact, CVID patients showed a decrease in Th17-cell frequency in parallel with the expansion of activated non-differentiated B cells (CD21(lowCD38(low. Moreover, Congenital Agammaglobulinemia patients, lacking B cells due to impaired early B-cell development, had a severe reduction of circulating Th17 cells. Finally, we found a direct correlation in healthy individuals between circulating Th17-cell frequency and both switched-memory B cells and serum BAFF levels, a crucial cytokine for B-cell survival. Overall, our data support a relationship between Th17-cell homeostasis and B-cell maturation, with implications for the understanding of the pathogenesis of inflammatory/autoimmune diseases and the physiology of B-cell depleting therapies.

  8. Dopamine favors expansion of glucocorticoid-resistant IL-17-producing T cells in multiple sclerosis.

    Science.gov (United States)

    Ferreira, Thais B; Barros, Priscila O; Teixeira, Bruna; Cassano, Tatiane; Centurião, Newton; Kasahara, Taissa M; Hygino, Joana; Vasconcelos, Claudia Cristina F; Filho, Helcio Alvarenga; Alvarenga, Regina; Wing, Ana Cristina; Andrade, Regis M; Andrade, Arnaldo F; Bento, Cleonice A M

    2014-10-01

    Dopamine (DA) is a neurotransmitter produced mainly in the central nervous system (CNS) that has immunomodulatory actions on T cells. As the multiple sclerosis (MS) has long been regarded as an autoimmune disease of CNS mediated by T cells, the objective of this study was to evaluate the impact of DA on in vitro functional status of T cells from relapsing-remitting (RR)-MS patients. Peripheral T-cells from RR-MS patients were activated by mitogens and cell proliferation and cytokine production were assayed by [(3)H]-thymidine uptake and ELISA, respectively. Our results demonstrated that DA enhanced in vitro T cell proliferation and Th17-related cytokines in MS-derived cell cultures. In addition, this catecholamine reduced Treg-related cytokines (IL-10 and TGF-β) release by activated CD4(+) T cells. These DA-induced effects on T cells were mainly dependent on IL-6 production by both polyclonally-activated CD4(+) T cells and LPS-stimulated monocytes. Furthermore, the production of IL-17 and IL-6 by MS-derived T cells was directly related with neurological disability (EDSS score), and the release of these cytokines was less sensitive to glucocorticoid inhibition in MS patients than in control group, mainly after DA addition. In conclusion, our data suggest that DA amplifies glucocorticoid-resistant Th17 phenotype in MS patients, and this phenomenon could be, at least in part, due to its ability to induce IL-6 production by monocytes and CD4(+) T cells.

  9. Pixelated neutron image plates

    Science.gov (United States)

    Schlapp, M.; Conrad, H.; von Seggern, H.

    2004-09-01

    Neutron image plates (NIPs) have found widespread application as neutron detectors for single-crystal and powder diffraction, small-angle scattering and tomography. After neutron exposure, the image plate can be read out by scanning with a laser. Commercially available NIPs consist of a powder mixture of BaFBr : Eu2+ and Gd2O3 dispersed in a polymer matrix and supported by a flexible polymer sheet. Since BaFBr : Eu2+ is an excellent x-ray storage phosphor, these NIPs are particularly sensitive to ggr-radiation, which is always present as a background radiation in neutron experiments. In this work we present results on NIPs consisting of KCl : Eu2+ and LiF that were fabricated into ceramic image plates in which the alkali halides act as a self-supporting matrix without the necessity for using a polymeric binder. An advantage of this type of NIP is the significantly reduced ggr-sensitivity. However, the much lower neutron absorption cross section of LiF compared with Gd2O3 demands a thicker image plate for obtaining comparable neutron absorption. The greater thickness of the NIP inevitably leads to a loss in spatial resolution of the image plate. However, this reduction in resolution can be restricted by a novel image plate concept in which a ceramic structure with square cells (referred to as a 'honeycomb') is embedded in the NIP, resulting in a pixelated image plate. In such a NIP the read-out light is confined to the particular illuminated pixel, decoupling the spatial resolution from the optical properties of the image plate material and morphology. In this work, a comparison of experimentally determined and simulated spatial resolutions of pixelated and unstructured image plates for a fixed read-out laser intensity is presented, as well as simulations of the properties of these NIPs at higher laser powers.

  10. B-cell infiltration and frequency of cytokine producing cells differ between localized and disseminated human cutaneous leishmaniases

    Directory of Open Access Journals (Sweden)

    MGS Vieira

    2002-10-01

    Full Text Available Biopsies from human localized cutaneous lesions (LCL n = 7 or disseminated lesions (DL n = 8 cases were characterized according to cellular infiltration,frequency of cytokine (IFN-g, TNF-alpha or iNOS enzyme producing cells. LCL, the most usual form of the disease with usually one or two lesions, exhibits extensive tissue damage. DL is a rare form with widespread lesions throughout the body; exhibiting poor parasite containment but less tissue damage. We demonstrated that LCL lesions exhibit higher frequency of B lymphocytes and a higher intensity of IFN-gamma expression. In both forms of the disease CD8+ were found in higher frequency than CD4+ T cells. Frequency of TNF-alpha and iNOS producing cells, as well as the frequency of CD68+ macrophages, did not differ between LCL and DL. Our findings reinforce the link between an efficient control of parasite and tissue damage, implicating higher frequency of IFN-gamma producing cells, as well as its possible counteraction by infiltrated B cells and hence possible humoral immune response in situ.

  11. Fibrin scaffold enhances function of insulin producing cells differentiated from human umbilical cord matrix-derived stem cells.

    Science.gov (United States)

    Seyedi, Fatemeh; Farsinejad, Alireza; Nematollahi-Mahani, Seyed Noureddin

    2017-04-01

    Tissue engineering is a new strategy which proposed to treat numerous human diseases nowadays. Three dimensional (3D) scaffolds fill the gap between two dimensional cell culture (2D) and animal tissues through mimicking the environmental behaviors surrounding the cells. In this study, hUCMs into insulin producing cells in fibrin scaffold were differentiated compare to conventional culture condition. Differentiation rate was estimated by real time PCR, immunocytochemistry (ICC) and the chemiluminesence (CLIA) and enzyme immunoassay (EIA). Real time PCR's results showed an increasing expression in NKX2.2, PDX1 and INS (producing the hormone insulin) genes in fibrin scaffold. Furthermore ICC analysis exhibited that insulin and pro-insulin proteins were more in fibrin scaffolds. CLIA and EIA on insulin and C peptide secretion indicated that both of groups were sensitive to the glucose challenge test but significant higher response was observed in fibrin scaffold (6.5 fold in 3D, 1.8 fold in 2D culture). It could be concluded that differentiation of hUCM cells into insulin producing cells in fibrin scaffold 3D culture system is much more efficient than 2D conventional culture system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Immunometabolic Regulation of Interleukin-17-Producing T Helper Cells: Uncoupling New Targets for Autoimmunity

    Science.gov (United States)

    Binger, Katrina J.; Côrte-Real, Beatriz F.; Kleinewietfeld, Markus

    2017-01-01

    Interleukin-17-producing T helper (Th17) cells are critical for the host defense of bacterial and fungal pathogens and also play a major role in driving pathogenic autoimmune responses. Recent studies have indicated that the generation of Th17 cells from naïve CD4+ T cells is coupled with massive cellular metabolic adaptations, necessary to cope with different energy and metabolite requirements associated with switching from a resting to proliferative state. Furthermore, Th17 cells have to secure these metabolic adaptations when facing nutrient-limiting environments, such as at the sites of inflammation. Accumulating data indicates that this metabolic reprogramming is significantly linked to the differentiation of T helper cells and, particularly, that the metabolic changes of Th17 cells and anti-inflammatory Forkhead box P3+ regulatory T cells are tightly and reciprocally regulated. Thus, a better understanding of these processes could offer potential new targets for therapeutic interventions for autoimmune diseases. In this mini-review, we will highlight some of the recent advances and discoveries in the field, with a particular focus on metabolic demands of Th17 cells and their implications for autoimmunity.

  13. Antimicrobial peptides (AMPs) produced by Saccharomyces cerevisiae induce alterations in the intracellular pH, membrane permeability and culturability of Hanseniaspora guilliermondii cells.

    Science.gov (United States)

    Branco, Patrícia; Viana, Tiago; Albergaria, Helena; Arneborg, Nils

    2015-07-16

    Saccharomyces cerevisiae produces antimicrobial peptides (AMPs) during alcoholic fermentation that are active against several wine-related yeasts (e.g. Hanseniaspora guilliermondii) and bacteria (e.g. Oenococcus oeni). In the present study, the physiological changes induced by those AMPs on sensitive H. guilliermondii cells were evaluated in terms of intracellular pH (pHi), membrane permeability and culturability. Membrane permeability was evaluated by staining cells with propidium iodide (PI), pHi was determined by a fluorescence ratio imaging microscopy (FRIM) technique and culturability by a classical plating method. Results showed that the average pHi of H. guilliermondii cells dropped from 6.5 (healthy cells) to 5.4 (damaged cells) after 20 min of exposure to inhibitory concentrations of AMPs, and after 24 h 77.0% of the cells completely lost their pH gradient (∆pH=pHi-pHext). After 24h of exposure to AMPs, PI-stained (dead) cells increased from 0% to 77.7% and the number of viable cells fell from 1×10(5) to 10 CFU/ml. This means that virtually all cells (99.99%) became unculturable but that a sub-population of 22.3% of the cells remained viable (as determined by PI staining). Besides, pHi results showed that after 24h, 23% of the AMP-treated cells were sub-lethally injured (with 0pH<3). Taken together, these results indicated that this subpopulation was under a viable but non-culturable (VBNC) state, which was further confirmed by recuperation assays. In summary, our study reveals that these AMPs compromise the plasma membrane integrity (and possibly also the vacuole membrane) of H. guilliermondii cells, disturbing the pHi homeostasis and inducing a loss of culturability. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Comparative analysis of hydrogen-producing bacteria and its immobilized cells for characteristics of hydrogen production

    Institute of Scientific and Technical Information of China (English)

    王相晶; 任南琪; 向文胜; 王爱杰; 林明; 郭婉茜

    2003-01-01

    A strain of hydrogen producing bacteria was immobilized by polyvinyl alcohol-boric acid method,with the addition of a small amount of calcium alginate. The immobilized cells were insensitive to the presence of traces of O2. Moreover, the immobilized cells increased both the evolution rate and the yield of hydrogen production. Batch experiments with a medium containing 10 g/L glucose demonstrated the yields of hydrogen production by the immobilized and free cells were 2.14 mol/mol glucose and 1.69 mol/mol glucose, respectively.In continuous cultures atmedium retention time of 2. 0 h, the yield and the evolution rate of hydrogen producmedium retention time of 6. 0 h, the yield and the evolution rate of hydrogen production by free cells were only 1.75 mol/mol glucose and 362.9ml/(L·h),respectively.

  15. Acetylcholine regulates pancreastatin secretion from the human pancreastatin-producing cell line (QGP-1N).

    Science.gov (United States)

    Funakoshi, A; Tateishi, K; Tsuru, M; Jimi, A; Wakasugi, H; Kono, A

    1991-07-01

    Studies were made of pancreastatin (PST) secretion from a human PST-producing cell line (QGP-1N) in response to various secretagogues. Cells with immunoreactivity for PST were observed in monolayer cultures of QGP-1N cells. Carbachol stimulated PST secretion and the intracellular Ca2+ mobilization concentration dependently in the range of 10(-6)-10(-4) M. The PST secretion and Ca2+ mobilization induced by carbachol were inhibited by atropine. The calcium ionophore (A23187) stimulated PST secretion. However, cholecystokinin and gastrin-releasing peptide did not stimulate either PST secretion or Ca2+ mobilization. Secretin also did not stimulate PST secretion. The glucose concentration in the culture medium had no effect on PST secretion. These results suggest that PST secretion is mainly regulated by acetylcholine through a muscarinic receptor, and that an increase in intracellular Ca2+ plays an important role in stimulus-secretion coupling in QGP-1N cells.

  16. Method of producing ceramic distribution members for solid state electrolyte cells

    Science.gov (United States)

    Clark, Douglas J. (Inventor); Galica, Leo M. (Inventor); Losey, Robert W. (Inventor); Suitor, Jerry W. (Inventor)

    1995-01-01

    A solid state electrolyte cells apparatus and method of producing is disclosed. The apparatus can be used for separating oxygen from an oxygen-containing feedstock or as a fuel cell for reacting fluids. Cells can be stacked so that fluids can be introduced and removed from the apparatus through ceramic distribution members having ports designed for distributing the fluids in parallel flow to and from each cell. The distribution members can also serve as electrodes to membranes or as membrane members between electrodes, The distribution member design does not contain any horizontal internal ports which allows the member to be thin. A method of tape casting in combination with an embossing method allows intricate radial ribs and bosses to be formed on each distribution member. The bosses serve as seals for the ports and allow the distribution members to be made without any horizontal internal ports.

  17. Design of a titering assay for lentiviral vectors utilizing direct extraction of DNA from transduced cells in microtiter plates

    Directory of Open Access Journals (Sweden)

    Michele E Murphy

    2016-01-01

    Full Text Available Using lentiviral vector products in clinical applications requires an accurate method for measuring transduction titer. For vectors lacking a marker gene, quantitative polymerase chain reaction is used to evaluate the number of vector DNA copies in transduced target cells, from which a transduction titer is calculated. Immune Design previously described an integration-deficient lentiviral vector pseudotyped with a modified Sindbis virus envelope for use in cancer immunotherapy (VP02, of the ZVex platform. Standard protocols for titering integration-competent lentiviral vectors employ commercial spin columns to purify vector DNA from transduced cells, but such columns are not optimized for isolation of extrachromosomal (nonintegrated DNA. Here, we describe a 96-well transduction titer assay in which DNA extraction is performed in situ in the transduction plate, yielding quantitative recovery of extrachromosomal DNA. Vector titers measured by this method were higher than when commercial spin columns were used for DNA isolation. Evaluation of the method's specificity, linear range, and precision demonstrate that it is suitable for use as a lot release assay to support clinical trials with VP02. Finally, the method is compatible with titering both integrating and nonintegrating lentiviral vectors, suggesting that it may be used to evaluate the transduction titer for any lentiviral vector.

  18. Bone acidic glycoprotein-75 is a major synthetic product of osteoblastic cells and localized as 75- and/or 50-kDa forms in mineralized phases of bone and growth plate and in serum.

    Science.gov (United States)

    Gorski, J P; Griffin, D; Dudley, G; Stanford, C; Thomas, R; Huang, C; Lai, E; Karr, B; Solursh, M

    1990-09-05

    Anti-peptide and anti-protein antisera were produced which both recognize bone acidic glycoprotein-75 (Mr = 75,000) and an apparent fragment or biosynthetic intermediate (Mr = 50,000) in calcified tissues and/or serum. A fragment-precursor relationship is suggested from the fact that closely spaced doublet polypeptides of Mr = 50,000 could be produced by proteolysis of the purified protein upon long term storage. No reactivity was detected with osteopontin, bone sialoprotein, or small bone proteoglycans. Bone acidic glycoprotein-75 represents 0.5-1% of the total radiolabeled proteins synthesized by explant cultures of neonatal calvaria or growth plate, by calvarial outgrowth cultures, and by rat osteosarcoma cells. Amounts produced by explant cultures and calvarial outgrowth cultures were similar to that for osteopontin, a major product of osteoblasts. In osteosarcoma cultures, 80% of labeled antigens were associated with the cell layer fraction wherein specific immunoprecipitation pelleted Mr = 50,000 and 75,000 sized antigens. Bone acidic glycoprotein-75 (Mr = 75,000) is enriched in 4 M guanidine HCl/0.5 EDTA extracts of neonatal rat bone and growth plate tissues, whereas largely absent from heart, lung, spleen, liver, brain, and kidney. Explant cultures of these noncalcifying tissues also synthesized bone acidic glycoprotein-75 antigen, but the quantities produced were only 5% or less that obtained with calvaria. By immunohistochemistry, antigenicity is associated with the bony shaft and calcified cartilage of long bones, but is absent from associated soft tissues. These finding demonstrate that bone acidic glycoprotein-75 is antigenically distinct, predominantly localized to calcified tissues, represents a major product of normal osteoblastic cells and may undergo a characteristic fragmentation in vivo and in vitro.

  19. Mechanical Interactions between Gas Diffusion Layers and Bipolar Plates in low Temperature Fuel Cells

    OpenAIRE

    Knöri, Torsten; Schulze, Mathias; Gülzow, Erich

    2007-01-01

    In contrast to stiff backing materials (e.g. carbon paper) softer ones like carbon cloth are compressed over the ribs of the gas distributors or impressed into the channels when the PEFC is assembled. During fuel cell optimisation the interactions between the gas diffusion layer and the flow field are frequently neglected; hence flow fields as well as gas diffusion layers are commonly optimized independently. The DLR has investigated these interactions with a two-stage approach: At firs...

  20. Birth of viable female dogs produced by somatic cell nuclear transfer.

    Science.gov (United States)

    Jang, G; Kim, M K; Oh, H J; Hossein, M S; Fibrianto, Y H; Hong, S G; Park, J E; Kim, J J; Kim, H J; Kang, S K; Kim, D Y; Lee, B C

    2007-03-15

    Since the only viable cloned offspring born in dogs was a male, the purpose of the present study was to produce female puppies by somatic cell nuclear transfer (SCNT). Adult ear fibroblasts from a 2-month-old female Afghan hound were isolated and used as donor cells. In vivo-matured canine oocytes surgically collected (approximately 72h after ovulation) from the oviducts of 23 donors were used for SCNT. After removal of the cumulus cells, oocytes were enucleated, microinjected, fused with a donor cell, and activated. A total of 167 reconstructed SCNT embryos were surgically transferred (Day 0) into the oviducts of 12 recipient bitches (average 13.9 embryos/recipient, range 6-22) with spontaneous, synchronous estrous cycles. Three pregnancies were detected by ultrasonography on Day 23, maintained to term, and three healthy female puppies (520, 460, and 520g), were delivered by Caesarean section on Day 60. These puppies were phenotypically and genotypically identical to the cell donor. In conclusion, we have provided the first demonstration that female dogs can be produced by nuclear transfer of ear fibroblasts into enucleated canine oocytes.

  1. Embryonic stem-like cells derived from in vitro produced bovine blastocysts

    Directory of Open Access Journals (Sweden)

    Erika Regina Leal de Freitas

    2011-06-01

    Full Text Available The aim of this work was to study the derivation of bovine embryonic stem-like (ES-like cells from the inner cell mass (ICM of in vitro produced blastocysts. The ICMs were mechanically isolated and six out of seventeen (35% ICMs could attach to a monolayer of murine embryonic fibroblasts (MEF. Ten days after, primary outgrowths were mechanically dissected into several small clumps and transferred to a new MEF layer. Cells were further propagated and passaged by physical dissociation over a 60 days period. The pluripotency of the bovine ES-like cells was confirmed by RT-PCR of Oct-4 and STAT-3 gene markers. The colonies were weakly stained for alkaline phosphatase and the mesoderm and endoderm differentiation gene markers such as GATA-4 and Flk-1, respectively, were not expressed. Embryoid bodies were spontaneously formed at the seventh passage. Results showed that bovine ES-like cells could be obtained and passaged by mechanical procedures from the fresh in vitro produced blastocysts.

  2. Volatile and non-volatile monoterpenes produced by elicitor-stimulated Cupressus lusitanica cultured cells.

    Science.gov (United States)

    De Alwis, Ransika; Fujita, Koki; Ashitani, Tatsuya; Kuroda, Ken'ichi

    2009-05-01

    Elicitor treatment initiates defense responses in cultured Cupressus lusitanica cells. In order to investigate the defense mechanism with a yeast extract elicitor, we carried out solid-phase microextraction coupled with gas chromatography for monoterpene analysis. Ten hydrocarbon monoterpenes, including high amounts of sabinene and limonene, were detected in the gas phase of the elicitor-treated cell cultures. Six oxidized monoterpenes including beta-thujaplicin were also detected in the ether extract of the cells and the medium. Time-course profiles of volatile monoterpenes showed that one group of hydrocarbon monoterpenes was maximized on the second day after elicitation, while the other group was maximized on the third day. There were no oxidized monoterpenes that are structurally related to sabinene and limonene in the gas phase or cell extracts, suggesting that these compounds are produced exclusively for emission. Other monoterpenes, which are produced during later stages of elicitation, are metabolized into more complex compounds such as oxidized monoterpenes, including beta-thujaplicin. Although terpinolene synthase was the principal monoterpene synthase in these cell cultures, terpinolene was detected only as a minor compound in the gas phase. The time course for terpinolene synthase activity coincided with beta-thujaplicin biosynthesis. Thus, most of the terpinolene is metabolized rapidly to oxidized terpenes such as beta-thujaplicin rather than emitted.

  3. HCV Specific IL-21 Producing T Cells but Not IL-17A Producing T Cells Are Associated with HCV Viral Control in HIV/HCV Coinfection

    Science.gov (United States)

    MacParland, Sonya A.; Fadel, Saleh M.; Mihajlovic, Vesna; Fawaz, Ali; Kim, Connie; Rahman, A. K. M. Nur-ur; Liu, Jun; Kaul, Rupert; Kovacs, Colin; Grebely, Jason; Dore, Gregory J.; Wong, David K.; Ostrowski, Mario A.

    2016-01-01

    Background Decreased hepatitis C virus (HCV) clearance, faster cirrhosis progression and higher HCV RNA levels are associated with Human Immunodeficiency virus (HIV) coinfection. The CD4+ T helper cytokines interleukin (IL)-21 and IL-17A are associated with virus control and inflammation, respectively, both important in HCV and HIV disease progression. Here, we examined how antigen-specific production of these cytokines during HCV mono and HIV/HCV coinfection was associated with HCV virus control. Methods We measured HCV-specific IL-21 and IL-17A production by transwell cytokine secretion assay in PBMCs from monoinfected and coinfected individuals. Viral control was determined by plasma HCV RNA levels. Results In acutely infected individuals, those able to establish transient/complete HCV viral control tended to have stronger HCV-specific IL-21-production than non-controllers. HCV-specific IL-21 production also correlated with HCV viral decline in acute infection. Significantly stronger HCV-specific IL-21 production was detected in HAART-treated coinfected individuals. HCV-specific IL-17A production was not associated with lower plasma HCV RNA levels in acute or chronic HCV infection and responses were stronger in HIV coinfection. HCV-specific IL-21/ IL-17A responses did not correlate with microbial translocation or fibrosis. Exogenous IL-21 treatment of HCV-specific CD8+ T cells from monoinfected individuals enhanced their function although CD8+ T cells from coinfected individuals were somewhat refractory to the effects of IL-21. Conclusions These data show that HCV-specific IL-21 and IL-17A-producing T cells are induced in HIV/HCV coinfection. In early HIV/HCV coinfection, IL-21 may contribute to viral control, and may represent a novel tool to enhance acute HCV clearance in HIV/HCV coinfected individuals. PMID:27124305

  4. [Cloning goat producing human lactoferrin with genetically modified donor cells selected by single or dual markers].

    Science.gov (United States)

    An, Liyou; Yuan, Yuguo; Yu, Baoli; Yang, Tingjia; Cheng, Yong

    2012-12-01

    We compared the efficiency of cloning goat using human lactoferrin (hLF) with genetically modified donor cells marked by single (Neo(r)) or double (Neo(r)/GFP) markers. Single marker expression vector (pBLC14) or dual markers expression vector (pAPLM) was delivered to goat fetal fibroblasts (GFF), and then the transgenic GFF was used as donor cells to produce transgenic goats. Respectively, 58.8% (20/34) and 86.7% (26/30) resistant cell lines confirmed the transgenic integration by PCR. Moreover, pAPLM cells lines were subcultured with several passages, only 20% (6/30) cell lines was observed fluorescence from each cell during the cell passage. Somatic cell nuclear transfer using the donor cells harbouring pBLC14 or pAPLM construct, resulting in a total of 806 reconstructed embryos, a pregnancy rate at 35 d (53.8%, 39.1%) and 60 d (26.9%, 21.7%), and an offspring birth rate (1.9%, 1.4%) with 5 and 7 newborn cloned goats, respectively. Transgene was confirmed by PCR and southern-blot in all cloned offspring. There were no significant differences at the reconstructed embryo fusion rates, pregnancy rates and the birth rate (P > 0.05) between single and double markers groups. The Neo(r)/GFP double markers could improve the reliability for accurately and efficiently selecting the genetically modified donor cells. No adverse effect was observed on the efficiency of transgenic goat production by SCNT using somatic cells transfected with double (Neo(r)/GFP) markers vector.

  5. Teratomas produced from human pluripotent stem cells xenografted into immunodeficient mice - a histopathology atlas.

    Science.gov (United States)

    Damjanov, Ivan; Andrews, Peter W

    2016-01-01

    This atlas illustrates the microscopic features of tumors produced from human pluripotent stem cells (hPSCs) xenografted into immunosuppressed mice, according to the generally accepted protocols for performing this teratoma assay of stem cell pluripotency. Microphotographs depict various hematoxylin and eosin (H&E) stained tissues derived from all three embryonic germ layers (ectoderm, mesoderm and endoderm). The appearance of persistent hPSC in teratomas is also described with special emphasis on the morphogenesis of embryoid bodies and yolk sac components surrounding them. The use of immunohistochemistry for analyzing hPSC-derived teratomas is also illustrated.

  6. Bench to batch: advances in plant cell culture for producing useful products.

    Science.gov (United States)

    Weathers, Pamela J; Towler, Melissa J; Xu, Jianfeng

    2010-02-01

    Despite significant efforts over nearly 30 years, only a few products produced by in vitro plant cultures have been commercialized. Some new advances in culture methods and metabolic biochemistry have improved the useful potential of plant cell cultures. This review will provide references to recent relevant reviews along with a critical analysis of the latest improvements in plant cell culture, co-cultures, and disposable reactors for production of small secondary product molecules, transgenic proteins, and other products. Some case studies for specific products or production systems are used to illustrate principles.

  7. Teratomas produced from human pluripotent stem cells xenografted into immunodeficient mice - a histopathology atlas

    Science.gov (United States)

    Damjanov, Ivan; Andrews, Peter W.

    2017-01-01

    This atlas illustrates the microscopic features of tumors produced from human pluripotent stem cells (hPSCs) xenografted into immunosuppressed mice, according to the generally accepted protocols for performing this teratoma assay of stem cell pluripotency. Microphotographs depict various hematoxylin and eosin (H&E) stained tissues derived from all three embryonic germ layers (ectoderm, mesoderm and endoderm). The appearance of persistent hPSC in teratomas is also described with special emphasis on the morphogenesis of embryoid bodies and yolk sac components surrounding them. The use of immunohistochemistry for analyzing hPSC-derived teratomas is also illustrated. PMID:28000905

  8. B-cell exposure to self-antigen induces IL-10 producing B cells as well as IL-6- and TNF-α-producing B-cell subsets in healthy humans

    DEFF Research Database (Denmark)

    Langkjær, Anina; Kristensen, Birte; Hansen, Bjarke E

    2012-01-01

    of IL-10 and TGF-β, in addition to TNF-α and IL-6. Pulsing with foreign antigen, tetanus toxoid (TT), induced a Th1-response with minimal IL-10 production. After thyroglobulin-pulsing, 1.10±0.50% of B cells and 1.00±0.20% of CD4(+) T cells produced IL-10, compared to 0.29±0.19% of B cells (P=0.01) and 0...

  9. Cinacalcet for Hypercalcemia Caused by Pulmonary Squamous Cell Carcinoma Producing Parathyroid Hormone-Related Peptide

    Directory of Open Access Journals (Sweden)

    Anneke Bech

    2012-01-01

    Full Text Available Background: Current treatments for hypercalcemia caused by lung cell carcinomas producing parathyroid hormone-related peptide (PTH-rp have limited efficacy, probably because of their lack of effect on PTH-rp secretion. In this case study we explored the efficacy of the calcimimetic cinacalcet as suppressor of PTH-rp production. Patient: A 57-year-old male with severe and recurrent hypercalcemia induced by a PTH-rp-producing squamous cell lung carcinoma, stage cT4N3M1b, poorly responding to standard treatments. Results: Serum PTH-rp levels were not affected by saline, calcitonin or zoledronate. PTH-rp decreased during chemotherapy and cinacalcet monotherapy. The combination of chemotherapy plus cinacalcet was most effective in rapidly reducing serum calcium and PTH-rp. Conclusion: This case study is the first to suggest that cinacalcet may be of value in some cases of PTH-rp-dependent hypercalcemia. Corroborative evidence is needed.

  10. Cinacalcet for Hypercalcemia Caused by Pulmonary Squamous Cell Carcinoma Producing Parathyroid Hormone-Related Peptide

    Science.gov (United States)

    Bech, Anneke; Smolders, Koen; Telting, Darryl; de Boer, Hans

    2012-01-01

    Background Current treatments for hypercalcemia caused by lung cell carcinomas producing parathyroid hormone-related peptide (PTH-rp) have limited efficacy, probably because of their lack of effect on PTH-rp secretion. In this case study we explored the efficacy of the calcimimetic cinacalcet as suppressor of PTH-rp production. Patient A 57-year-old male with severe and recurrent hypercalcemia induced by a PTH-rp-producing squamous cell lung carcinoma, stage cT4N3M1b, poorly responding to standard treatments. Results Serum PTH-rp levels were not affected by saline, calcitonin or zoledronate. PTH-rp decreased during chemotherapy and cinacalcet monotherapy. The combination of chemotherapy plus cinacalcet was most effective in rapidly reducing serum calcium and PTH-rp. Conclusion This case study is the first to suggest that cinacalcet may be of value in some cases of PTH-rp-dependent hypercalcemia. Corroborative evidence is needed. PMID:22379470

  11. [Selection of retroviral vector producing cell lines and gene transfer into hematopoietic cells].

    Science.gov (United States)

    Bagnis, C; Mannoni, P

    1996-04-01

    Transduction and expression of a transgene in hematopoietic stem cells with retroviral vectors still remain major challenges for gene therapy in blood disorders. Use of an easily detectable gene marker, such as the nlsLacZ, at the laboratory and clinical levels, provides a powerful approach of these two combined problems.

  12. T cell interleukin-17 induces stromal cells to produce proinflammatory and hematopoietic cytokines.

    Science.gov (United States)

    Fossiez, F; Djossou, O; Chomarat, P; Flores-Romo, L; Ait-Yahia, S; Maat, C; Pin, J J; Garrone, P; Garcia, E; Saeland, S; Blanchard, D; Gaillard, C; Das Mahapatra, B; Rouvier, E; Golstein, P; Banchereau, J; Lebecque, S

    1996-06-01

    Analysis of the cDNA encoding murine interleukin (IL) 17 (cytotoxic T lymphocyte associated antigen 8) predicted a secreted protein sharing 57% amino acid identity with the protein predicted from ORF13, an open reading frame of Herpesvirus saimiri. Here we report on the cloning of human IL-17 (hIL-17), the human counterpart of murine IL-17. hIL-17 is a glycoprotein of 155 amino acids secreted as an homodimer by activated memory CD4+ T cells. Although devoid of direct effects on cells of hematopoietic origin, hIL-17 and the product of its viral counterpart, ORF13, stimulate epithelial, endothelial, and fibroblastic cells to secrete cytokines such as IL-6, IL-8, and granulocyte-colony-stimulating factor, as well as prostaglandin E2. Furthermore, when cultured in the presence of hIL-17, fibroblasts could sustain the proliferation of CD34+ hematopoietic progenitors and their preferential maturation into neutrophils. These observations suggest that hIL-17 may constitute (a) an early initiator of the T cell-dependent inflammmatory reaction; and (b) an element of the cytokine network that bridges the immune system to hematopoiesis.

  13. Removal of Cadmium and Zinc from Soil using Immobilized Cell of Biosurfactant Producing Bacteria

    Directory of Open Access Journals (Sweden)

    Charoon Sarin

    2010-07-01

    Full Text Available Immobilized biosurfactant producing bacteria (Bacillus subtilis TP8 and Pseudomonas fluorescens G7 were assessed for survival in heavy metal contaminated soil and for their ability to remove cadmium and zinc from contaminated soil. P. fluorescens G7 was considered to be a good candidate for bioremediation of heavy metals because of its high minimum inhibitory concentrations (MIC for each heavy metal and because of the obviously increased numbers of cell surviving after incubation in the heavy metal contaminated soil up to 4 weeks. The results of soil remediation showed that approximately 19% of Zn and 16.7% of Cd could be removed by this immobilized biosurfactant producing bacteria after incubation for 2 weeks. The results confirm the potential applicability of the immobilized biosurfactant producing bacteria for heavy metal bioremediation.

  14. Plate tectonics conserves angular momentum

    Directory of Open Access Journals (Sweden)

    C. Bowin

    2009-03-01

    Full Text Available A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4 E+27 kgm2s−1. Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates. Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth. The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant velocity on the crests of convection cells driven by rising heat. These results imply that spreading centers are primarily passive reactive

  15. Ultrastructural changes produced in Ehrlich ascites carcinoma cells by ultraviolet-visible radiation in the presence of melanins

    Energy Technology Data Exchange (ETDEWEB)

    Lea, P.J.; Pawlowski, A.; Persad, S.D.; Menon, I.A.; Haberman, H.F.

    1988-01-01

    Irradiation of Ehrlich ascites carcinoma (EAC) cells in the presence of pheomelanin, i.e., red hair melanin (RHM), has been reported to produce extensive cell lysis. Irradiation in the presence of eumelanin, i.e., black hair melanin (BHM), or irradiation in the absence of either type of melanin did not produce this effect. We observed that RHM particles penetrated the cell membrane without apparent structural damage to the cell or the cell membrane. Irradiation of the cells in the absence of melanin did not produce any changes in the ultrastructure of the cells. Incubation of the cells in the dark in the presence of RHM produced only minor structural, mainly cytoplasmic changes. Irradiation of the cells in the presence of RHM produced extensive ultrastructural changes prior to complete cell lysis; these changes were more severe than the effects of incubation of the cells in the dark in the presence of RHM. When the cells incubated in the dark or irradiated in the presence of latex particles or either one of the eumelanins particles, viz. BHM or synthetic dopa melanin, these particles did not penetrate into the cells or produce any ultrastructural changes. These particles were in fact not even ingested by the cells.

  16. New cell line development for antibody-producing Chinese hamster ovary cells using split green fluorescent protein

    Directory of Open Access Journals (Sweden)

    Kim Yeon-Gu

    2012-05-01

    Full Text Available Abstract Background The establishment of high producer is an important issue in Chinese hamster ovary (CHO cell culture considering increased heterogeneity by the random integration of a transfected foreign gene and the altered position of the integrated gene. Fluorescence-activated cell sorting (FACS-based cell line development is an efficient strategy for the selection of CHO cells in high therapeutic protein production. Results An internal ribosome entry site (IRES was introduced for using two green fluorescence protein (GFP fragments as a reporter to both antibody chains, the heavy chain and the light chain. The cells co-transfected with two GFP fragments showed the emission of green fluorescence by the reconstitution of split GFP. The FACS-sorted pool with GFP expression had a higher specific antibody productivity (qAb than that of the unsorted pool. The qAb was highly correlated with the fluorescence intensity with a high correlation coefficient, evidenced from the analysis of median GFP and qAb in individual selected clones. Conclusions This study proved that the fragment complementation for split GFP could be an efficient indication for antibody production on the basis of high correlation of qAb with reconstitution of GFP. Taken together, we developed an efficient FACS-based screening method for high antibody-producing CHO cells with the benefits of the split GFP system.

  17. Removal of Cadmium and Zinc from Soil using Immobilized Cell of Biosurfactant Producing Bacteria

    OpenAIRE

    Charoon Sarin; Siripun Sarin

    2010-01-01

    Immobilized biosurfactant producing bacteria (Bacillus subtilis TP8 and Pseudomonas fluorescens G7) were assessed for survival in heavy metal contaminated soil and for their ability to remove cadmium and zinc from contaminated soil. P. fluorescens G7 was considered to be a good candidate for bioremediation of heavy metals because of its high minimum inhibitory concentrations (MIC) for each heavy metal and because of the obviously increased numbers of cell surviving after incubation in the hea...

  18. Human tolerogenic dendritic cells produce IL-35 in the absence of other IL-12 family members.

    Science.gov (United States)

    Dixon, Karen O; van der Kooij, Sandra W; Vignali, Dario A A; van Kooten, Cees

    2015-06-01

    IL-35 is a cytokine of the IL-12 family, existing as a heterodimer of IL-12p35 and Ebi3. IL-35 has anti-inflammatory properties and is produced by regulatory T cells in humans and mice, where it is required for optimal suppression of immune responses. Distinct from other IL-12 cytokines, the expression of IL-35 has not been described in antigen-presenting cells. In view of the immune-regulatory properties of IL-35, we investigated the expression, regulation, and function of IL-12p35 and Ebi3 in human monocyte-derived dendritic cells and tolerogenic DCs (tolDCs). These tolDCs do not produce IL-12p70 or the homodimer IL-12p40. We demonstrate that tolDCs completely lack transcriptional expression of IL-12p40. However, tolDCs maintain mRNA expression of IL-12p35 and Ebi3. Using intracellular flow cytometry and Western blot analysis, we show that tolDCs produce Ebi3 and IL-12p35, and both can be enhanced upon stimulation with IFN-γ, LPS, or CD40L. tolDCs supernatants have the capacity to suppress T-cell activation. Using IL12A silencing, we demonstrate that IL-12p35 is required for tolDCs to reach their full suppressive potential. Taken together, our results indicate that tolDCs produce IL-35, providing an additional novel mechanism by which tolDCs elicit their tolerogenic potential.

  19. Mesorhizobium loti Produces nodPQ-Dependent Sulfated Cell Surface Polysaccharides▿

    OpenAIRE

    Townsend, Guy E.; Forsberg, Lennart S.; Keating, David H.

    2006-01-01

    Leguminous plants and bacteria from the family Rhizobiaceae form a symbiotic relationship, which culminates in novel plant structures called root nodules. The indeterminate symbiosis that forms between Sinorhizobium meliloti and alfalfa requires biosynthesis of Nod factor, a β-1,4-linked lipochitooligosaccharide that contains an essential 6-O-sulfate modification. S. meliloti also produces sulfated cell surface polysaccharides, such as lipopolysaccharide (LPS). The physiological function of s...

  20. Electrochemical performance of electroless nickel plated silicon electrodes for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Cetinkaya, T., E-mail: tcetinkaya@sakarya.edu.tr; Uysal, M.; Akbulut, H.

    2015-04-15

    Highlights: • Si/Ni composite powders were produced via electroless plating method. • Increasing content of the nickel on the surface of the silicon powders caused increasing discharge capacity. • The Si/Ni composite electrode produced using 40 g/L NiCl{sub 2} exhibited 246 mAh/g discharge capacity after 30 cycles. - Abstract: In this study, nickel plated silicon powders were produced using an electroless deposition process. The nickel content on the surface of silicon powders was changed by using different concentrations of NiCl{sub 2} in the plating bath. The surface morphology of the produced Ni plated composite powders was characterized using scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) was used to determine the elemental surface composition of the composites. X-ray diffraction (XRD) analysis was performed to investigate the structure of the nickel plated silicon powders. Electrochemical cycling test of the nickel plated silicon electrodes were performed at a constant current of 100 mA/g in CR2016 test cells. In order to investigate electrochemical reactions of the nickel plated silicon powders with electrolyte, cyclic voltammetry test was performed at a scan rate of 0.1 mV/s. Among the used concentrations, the nickel plated silicon electrode produced using 40 g/L NiCl{sub 2} had a 246 mAh/g discharge capacity after 30 cycles.

  1. Characteristics of calves produced with sperm sexed by flow cytometry/cell sorting.

    Science.gov (United States)

    Tubman, L M; Brink, Z; Suh, T K; Seidel, G E

    2004-04-01

    The objectives of this study were to determine whether calves produced by sexed sperm differed from controls and to what extent the sex ratio of calves was altered by the sexing procedure. Data were collected from 1,169 calves produced from sperm sexed by flow cytometry/cell sorting after staining with Hoechst 33342, and 793 calves produced from control sperm during breeding trials between 1997 and 2001. Least squares ANOVA were completed using factors of treatment (sexed vs. control sperm), 19 management groups from 13 field trials, and calf sex. Responses analyzed include gestation length, birth weight, calving ease, calf vigor, weaning weight, abortion rate, and death rates (neonatal and through weaning). No significant difference was observed for any response due to treatment or treatment interactions (P > 0.10). Therefore, calves produced from sexed sperm grew and developed normally both pre- and postnatally. A neurological disorder was observed in four control calves and one sexed calf from one farm. No gross anatomical abnormalities were reported for any calves in the study. Differences were observed for all responses among management groups (P Flow cytometry/cell sorting can be used to preselect sex of calves safely with approximately 90% accuracy.

  2. Virus-producing cells determine the host protein profiles of HIV-1 virion cores

    Directory of Open Access Journals (Sweden)

    Santos Steven

    2012-08-01

    Full Text Available Abstract Background Upon HIV entry into target cells, viral cores are released and rearranged into reverse transcription complexes (RTCs, which support reverse transcription and also protect and transport viral cDNA to the site of integration. RTCs are composed of viral and cellular proteins that originate from both target and producer cells, the latter entering the target cell within the viral core. However, the proteome of HIV-1 viral cores in the context of the type of producer cells has not yet been characterized. Results We examined the proteomic profiles of the cores purified from HIV-1 NL4-3 virions assembled in Sup-T1 cells (T lymphocytes, PMA and vitamin D3 activated THP1 (model of macrophages, mMΦ, and non-activated THP1 cells (model of monocytes, mMN and assessed potential involvement of identified proteins in the early stages of infection using gene ontology information and data from genome-wide screens on proteins important for HIV-1 replication. We identified 202 cellular proteins incorporated in the viral cores (T cells: 125, mMΦ: 110, mMN: 90 with the overlap between these sets limited to 42 proteins. The groups of RNA binding (29, DNA binding (17, cytoskeleton (15, cytoskeleton regulation (21, chaperone (18, vesicular trafficking-associated (12 and ubiquitin-proteasome pathway-associated proteins (9 were most numerous. Cores of the virions from SupT1 cells contained twice as many RNA binding proteins as cores of THP1-derived virus, whereas cores of virions from mMΦ and mMN were enriched in components of cytoskeleton and vesicular transport machinery, most probably due to differences in virion assembly pathways between these cells. Spectra of chaperones, cytoskeletal proteins and ubiquitin-proteasome pathway components were similar between viral cores from different cell types, whereas DNA-binding and especially RNA-binding proteins were highly diverse. Western blot analysis showed that within the group of overlapping proteins

  3. Characterisation of micro direct methanol fuel cells with silicon plate supported integrated ionomer membranes

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent; Dalslet, Bjarke Thomas; Kallesee, C.

    2013-01-01

    This work deals with the investigation and fabrication of Micro Direct Methanol Fuel Cells (μDMFC). They are investigated as a possible alternative for zinc-air batteries in small size consumer devices such as hearing aids. In such devices the conventional rechargeable batteries such as lithium......-ion batteries have insufficiently low energy density in the range 240 Wh/L to 300 Wh/L Methanol is a promising fuel for such devices due to the high energy density, with pure methanol having an energy density of 4400 Wh/L. Using a liquid fuel also allows refueling, which can be achieved much faster than battery...

  4. Hexagonal plate-like magnetite nanocrystals produced in komatiite-H2O-CO2 reaction system at 450°C

    Science.gov (United States)

    Hao, Xi-Luo; Li, Yi-Liang

    2015-10-01

    Batch experiments of komatiite-H2O-CO2 system with temperatures from 200 to 450°C were performed to simulate the interactions between the newly formed ultramafic crust and the proto-atmosphere on Earth before the formation of its earliest ocean. Particularly, magnetite nanocrystals were observed in the experiment carried out at 450°C that are characterized by their hexagonal platelet-like morphology and porous structure. Exactly the same set of lattice fringes on the two opposite sides of one pore suggests post-crystallization erosion. The results demonstrate that magnetite could be produced by the direct interactions between the ultramafic rocky crust and the atmosphere before the formation of the ocean on the Hadean Earth. These magnetite nanoparticles could serve as a catalyst in the synthesis of simple organic molecules during the organochemical evolution towards life.

  5. Electroendocytosis is driven by the binding of electrochemically produced protons to the cell's surface.

    Directory of Open Access Journals (Sweden)

    Nadav Ben-Dov

    Full Text Available Electroendocytosis involves the exposure of cells to pulsed low electric field and is emerging as a complementary method to electroporation for the incorporation of macromolecules into cells. The present study explores the underlying mechanism of electroendocytosis and its dependence on electrochemical byproducts formed at the electrode interface. Cell suspensions were exposed to pulsed low electric field in a partitioned device where cells are spatially restricted relative to the electrodes. The cellular uptake of dextran-FITC was analyzed by flow cytometery and visualized by confocal microscopy. We first show that uptake occurs only in cells adjacent to the anode. The enhanced uptake near the anode is found to depend on electric current density rather than on electric field strength, in the range of 5 to 65 V/cm. Electrochemically produced oxidative species that impose intracellular oxidative stress, do not play any role in the stimulated uptake. An inverse dependence is found between electrically induced uptake and the solution's buffer capacity. Electroendocytosis can be mimicked by chemically acidifying the extracellular solution which promotes the enhanced uptake of dextran polymers and the uptake of plasmid DNA. Electrochemical production of protons at the anode interface is responsible for inducing uptake of macromolecules into cells exposed to a pulsed low electric field. Expanding the understanding of the mechanism involved in electric fields induced drug-delivery into cells, is expected to contribute to clinical therapy applications in the future.

  6. Splenic Stromal Cells from Aged Mice Produce Higher Levels of IL-6 Compared to Young Mice

    Science.gov (United States)

    Park, Jihyun; Miyakawa, Takuya; Shiokawa, Aya; Nakajima-Adachi, Haruyo; Hachimura, Satoshi

    2014-01-01

    Inflamm-aging indicates the chronic inflammatory state resulting from increased secretion of proinflammatory cytokines and mediators such as IL-6 in the elderly. Our principle objective was to identify cell types that were affected with aging concerning IL-6 secretion in the murine model. We compared IL-6 production in spleen cells from both young and aged mice and isolated several types of cells from spleen and investigated IL-6 mRNA expression and protein production. IL-6 protein productions in cultured stromal cells from aged mice spleen were significantly high compared to young mice upon LPS stimulation. IL-6 mRNA expression level of freshly isolated stromal cells from aged mice was high compared to young mice. Furthermore, stromal cells of aged mice highly expressed IL-6 mRNA after LPS injection in vivo. These results suggest that stromal cells play a role in producing IL-6 in aged mice and imply that they contribute to the chronic inflammatory condition in the elderly. PMID:24729663

  7. Antiviral activity produced by an IPNV-carrier EPC cell culture confers resistance to VHSV infection.

    Science.gov (United States)

    Jurado, María Teresa; García-Valtanen, Pablo; Estepa, Amparo; Perez, Luis

    2013-10-25

    Infectious pancreatic necrosis virus (IPNV), a fish birnavirus, can establish a persistent infection on epithelioma papulosum cyprinid (EPC) cells producing a carrier state where a small fraction of IPNV-infected cells is maintained in the culture after continuous subculture. The EPC(IPNV) cells are resistant to challenge with IPNV as well as to challenge with viral hemorrhagic septicemia virus (VHSV), a rhabdovirus. In this work, the antiviral effect of the IPNV carrier culture conditioned medium (EPC(IPNV)-CM) was tested and analyzed in detail. EPC cells treated with the carrier culture supernatant become protected against VHSV challenge. Size-fractionation by filtration and acid and heat treatment showed that the IPNV persistently infected cells release an acid-resistant soluble factor in the molecular weight fraction bellow 50 kDa. The capacity of the EPC(IPNV)-CM to induce cytokine genes in EPC cells was also determined by real-time RT-PCR. We found that there is a positive correlation between up-regulation of mx gene expression in EPC cells treated with EPC(IPNV)-CM and protection against VHSV challenge. Our findings indicate that the control of IPNV multiplication in the carrier culture as well as the interference with rhabdovirus replication are connected to the production and release of an antiviral (interferon-like) factor to the medium.

  8. Cell recycled culture of succinic acid-producing Anaerobiospirillum succiniciproducens using an internal membrane filtration system.

    Science.gov (United States)

    Lee, Pyung-Cheon; Lee, Sang-Yup; Chang, Ho-Nam

    2008-07-01

    Cell recycled culture of succinic acid-producing Anaerobiospirillum succiniciproducens was anaerobically carried out using an internal membrane filter module in order to examine the physiological response of A. succiniciproducens to a high-cell-density environment. The optimal growth of A. succiniciproducens and its enhanced succinic acid productivity were observed under CO2-rich conditions, established by adding NaHCO3 and Na2CO3, in the cell recycled system. A. succiniciproducens grew up to 6.50 g-DCW/l, the highest cell concentration obtained so far, in cell recycled cultures. The cells did not change their morphology, which is known to be easily changed in unfavorable or stress environments. The maximum productivity of succinic acid was about 3.3 g/l/h, which is 3.3 times higher than those obtained in batch cultures. These results can serve as a guide for designing highly efficient cell recycled systems for succinic acid at a commercial level.

  9. Distribution of Nitric Oxide-Producing Cells along Spinal Cord in Urodeles

    Directory of Open Access Journals (Sweden)

    Mayada A Mahmoud

    2014-09-01

    Full Text Available Nitric oxide is a unique neurotransmitter, which participates in many physiological and pathological processes in the organism. There are little data about the neuronal nitric oxide synthase immunoreactivity in the spinal cord of amphibians. In this respect, the present study aims to investigate the distribution of nitric oxide producing cells in the spinal cord of urodele and to find out the possibility of a functional locomotory role to this neurotransmitter. The results of the present study demonstrate a specific pattern of NADPH-d labeling in the selected amphibian model throughout the spinal cord length as NADPH-d-producing cells and fibres were present in almost all segments of the spinal cord of the salamander investigated. However, their number, cytological characteristics and labeling intensity varied significantly. It was noticed that the NO-producing cells (NO-PC were accumulated in the ventral side of certain segments in the spinal cord corresponding to the brachial and sacral plexuses. In addition, the number of NO-PC was found to be increased also at the beginning of the tail and this could be due to the fact that salamanders are tetrapods having bimodal locomotion, namely swimming and walking.

  10. Hepatitis E Virus Produced from Cell Culture Has a Lipid Envelope.

    Directory of Open Access Journals (Sweden)

    Ying Qi

    Full Text Available The absence of a productive cell culture system hampered detailed analysis of the structure and protein composition of the hepatitis E virion. In this study, hepatitis E virus from a robust HEV cell culture system and from the feces of infected monkeys at the peak of virus excretion was purified by ultra-centrifugation. The common feature of the two samples after ultracentrifugation was that the ORF2 protein mainly remained in the top fractions. The ORF2 protein from cell culture system was glycosylated, with an apparent molecular weight of 88 kDa, and was not infectious in PLC/PRF/5 cells. The ORF2 protein in this fraction can bind to and protect HEV RNA from digestion by RNase A. The RNA-ORF2 product has a similar sedimentation coefficient to the virus from feces. The viral RNA in the cell culture supernatant was mainly in the fraction of 1.15 g/cm3 but that from the feces was mainly in the fraction of 1.21 g/cm3. Both were infectious in PLC/PRF/5 cells. And the fraction in the middle of the gradient (1.06 g/cm3 from the cell culture supernatant,but not that from the feces, also has ORF2 protein and HEV RNA but was not infectious in PLC/PRF/5.The infectious RNA-rich fraction from the cell culture contained ORF3 protein and lipid but the corresponding fraction from feces had no lipid and little ORF3 protein. The lipid on the surface of the virus has no effect on its binding to cells but the ORF3 protein interferes with binding. The result suggests that most of the secreted ORF2 protein is not associated with HEV RNA and that hepatitis E virus produced in cell culture differs in structure from the virus found in feces in that it has a lipid envelope.

  11. Mitochondrial Respiration in Insulin-Producing β-Cells: General Characteristics and Adaptive Effects of Hypoxia.

    Science.gov (United States)

    Hals, Ingrid K; Bruerberg, Simon Gustafson; Ma, Zuheng; Scholz, Hanne; Björklund, Anneli; Grill, Valdemar

    2015-01-01

    To provide novel insights on mitochondrial respiration in β-cells and the adaptive effects of hypoxia. Insulin-producing INS-1 832/13 cells were exposed to 18 hours of hypoxia followed by 20-22 hours re-oxygenation. Mitochondrial respiration was measured by high-resolution respirometry in both intact and permeabilized cells, in the latter after establishing three functional substrate-uncoupler-inhibitor titration (SUIT) protocols. Concomitant measurements included proteins of mitochondrial complexes (Western blotting), ATP and insulin secretion. Intact cells exhibited a high degree of intrinsic uncoupling, comprising about 50% of oxygen consumption in the basal respiratory state. Hypoxia followed by re-oxygenation increased maximal overall respiration. Exploratory experiments in peremabilized cells could not show induction of respiration by malate or pyruvate as reducing substrates, thus glutamate and succinate were used as mitochondrial substrates in SUIT protocols. Permeabilized cells displayed a high capacity for oxidative phosphorylation for both complex I- and II-linked substrates in relation to maximum capacity of electron transfer. Previous hypoxia decreased phosphorylation control of complex I-linked respiration, but not in complex II-linked respiration. Coupling control ratios showed increased coupling efficiency for both complex I- and II-linked substrates in hypoxia-exposed cells. Respiratory rates overall were increased. Also previous hypoxia increased proteins of mitochondrial complexes I and II (Western blotting) in INS-1 cells as well as in rat and human islets. Mitochondrial effects were accompanied by unchanged levels of ATP, increased basal and preserved glucose-induced insulin secretion. Exposure of INS-1 832/13 cells to hypoxia, followed by a re-oxygenation period increases substrate-stimulated respiratory capacity and coupling efficiency. Such effects are accompanied by up-regulation of mitochondrial complexes also in pancreatic islets

  12. Murine hematopoietic progenitor cells produce IL-6 in response to IgE.

    Science.gov (United States)

    Schneider, E; Salachas, F; Lemoine, F M; Arnould, A; Machavoine, F; Ploemacher, R E; Dy, M

    1995-04-01

    Similarly to interleukin-3 (IL-3), IgE is capable of inducing IL-6 production by murine bone marrow cells (BMC). IgE responder cells do not belong to the mature bone marrow compartment but coenrich with hematopoietic progenitors in the low-density fraction of a discontinuous Ficoll gradient. A significant enhancement of IL-6 production is observed after a 4-hour stimulation, reaching a maximum between 24 and 48 hours and is preceded by increased mRNA expression. The effect of IgE on IL-6 production is not mediated by IL-3 since it is not modified by anti-IL-3 antibodies. Upon a 4-hour exposure to IgE or IL-3, a similar percentage of progenitor-enriched BMC expresses IL-6 mRNA (3.9 and 5.4%, respectively, as determined by in situ hybridization), which is not further increased by a combination of both stimuli. IgE and IL-3 responder cells also cannot be distinguished on the basis of size, internal structure, and rhodamine (Rh) retention. The BMC sorted in the most fluorescent Rhbright subset (approximately 0.2% of total BMC) produce 30- to 40-fold more IL-6 than unfractionated cells and are similarly enriched for CFU-cells (CFU-C). The most primitive cells concentrated in the Rhdull fraction do not express this biological activity. The sorted Rhbright population does not contain mature mast cells/basophils or monocytes, and IL-6 is not produced in response to Fc epsilon RI cross-linkage after presensitization with IgE.

  13. Encapsulated galanin-producing cells attenuate focal epileptic seizures in the hippocampus.

    Science.gov (United States)

    Nikitidou, Litsa; Torp, Malene; Fjord-Larsen, Lone; Kusk, Philip; Wahlberg, Lars U; Kokaia, Mérab

    2014-01-01

    Encapsulated cell biodelivery (ECB) is a relatively safe approach, since the devices can be removed in the event of adverse effects. The main objectives of the present study were to evaluate whether ECB could be a viable alternative of cell therapy for epilepsy. We therefore developed a human cell line producing galanin, a neuropeptide that has been shown to exert inhibitory effects on seizures, most likely acting via decreasing glutamate release from excitatory synapses. To explore whether ECB of genetically modified galanin-producing human cell line could provide seizure-suppressant effects, and test possible translational prospect for clinical application, we implanted ECB devices bilaterally into the hippocampus of rats subjected to rapid kindling, a model for recurrent temporal lobe seizures. Two clones from a genetically modified human cell line secreting different levels of galanin were tested. Electroencephalography (EEG) recordings and stimulations were performed by electrodes implanted into the hippocampus at the same surgical session as ECB devices. One week after the surgery, rapid kindling stimulations were initiated. Enzyme-linked immunosorbent assay (ELISA) measurements prior to device implantation showed a release of galanin on average of 8.3 ng/mL/24 h per device for the low-releasing clone and 12.6 ng/mL/24 h per device for the high-releasing clone. High-releasing galanin-producing ECB devices moderately decreased stimulation-induced focal afterdischarge duration, whereas low-releasing ECB devices had no significant effect. Our study shows that galanin-releasing ECB devices moderately suppress focal stimulation-induced recurrent seizures. Despite this moderate effect, the study provides conceptual proof that ECB could be a viable alternative approach to cell therapy in humans, with the advantage that the treatment could be terminated by removing these devices from the brain. Thereby, this strategy provides a higher level of safety for future

  14. A rho GDP dissociation inhibitor produced by apoptotic T-cells inhibits growth of Mycobacterium tuberculosis.

    Science.gov (United States)

    Venkatasubramanian, Sambasivan; Dhiman, Rohan; Paidipally, Padmaja; Cheekatla, Satyanarayana S; Tripathi, Deepak; Welch, Elwyn; Tvinnereim, Amy R; Jones, Brenda; Theodorescu, Dan; Barnes, Peter F; Vankayalapati, Ramakrishna

    2015-02-01

    In this study, we found that a subpopulation of CD4(+)CD25(+) (85% Foxp3(+)) cells from persons with latent tuberculosis infection (LTBI) inhibits growth of M. tuberculosis (M. tb) in human monocyte-derived macrophages (MDMs). A soluble factor, Rho GDP dissociation inhibitor (D4GDI), produced by apoptotic CD4(+)CD25(+) (85% Foxp3(+)) cells is responsible for this inhibition of M. tb growth in human macrophages and in mice. M. tb-expanded CD4(+C)D25(+)Foxp3(+)D4GDI(+) cells do not produce IL-10, TGF-β and IFN-γ. D4GDI inhibited growth of M. tb in MDMs by enhancing production of IL-1β, TNF-α and ROS, and by increasing apoptosis of M. tb-infected MDMs. D4GDI was concentrated at the site of disease in tuberculosis patients, with higher levels detected in pleural fluid than in serum. However, in response to M. tb, PBMC from tuberculosis patients produced less D4GDI than PBMC from persons with LTBI. M. tb-expanded CD4+CD25+ (85% Foxp3(+)) cells and D4GDI induced intracellular M. tb to express the dormancy survival regulator DosR and DosR-dependent genes, suggesting that D4GDI induces a non-replicating state in the pathogen. Our study provides the first evidence that a subpopulation of CD4(+)CD25(+) (85% Foxp3+) cells enhances immunity to M. tb, and that production of D4GDI by this subpopulation inhibits M. tb growth.

  15. A rho GDP dissociation inhibitor produced by apoptotic T-cells inhibits growth of Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Sambasivan Venkatasubramanian

    2015-02-01

    Full Text Available In this study, we found that a subpopulation of CD4(+CD25(+ (85% Foxp3(+ cells from persons with latent tuberculosis infection (LTBI inhibits growth of M. tuberculosis (M. tb in human monocyte-derived macrophages (MDMs. A soluble factor, Rho GDP dissociation inhibitor (D4GDI, produced by apoptotic CD4(+CD25(+ (85% Foxp3(+ cells is responsible for this inhibition of M. tb growth in human macrophages and in mice. M. tb-expanded CD4(+CD25(+Foxp3(+D4GDI(+ cells do not produce IL-10, TGF-β and IFN-γ. D4GDI inhibited growth of M. tb in MDMs by enhancing production of IL-1β, TNF-α and ROS, and by increasing apoptosis of M. tb-infected MDMs. D4GDI was concentrated at the site of disease in tuberculosis patients, with higher levels detected in pleural fluid than in serum. However, in response to M. tb, PBMC from tuberculosis patients produced less D4GDI than PBMC from persons with LTBI. M. tb-expanded CD4+CD25+ (85% Foxp3(+ cells and D4GDI induced intracellular M. tb to express the dormancy survival regulator DosR and DosR-dependent genes, suggesting that D4GDI induces a non-replicating state in the pathogen. Our study provides the first evidence that a subpopulation of CD4(+CD25(+ (85% Foxp3+ cells enhances immunity to M. tb, and that production of D4GDI by this subpopulation inhibits M. tb growth.

  16. ADAM12 produced by tumor cells rather than stromal cells accelerates breast tumor progression

    DEFF Research Database (Denmark)

    Frohlich, Camilla; Nehammer, Camilla; Albrechtsen, Reidar

    2011-01-01

    Expression of ADAM12 is low in most normal tissues, but is markedly increased in numerous human cancers, including breast carcinomas. We have previously shown that overexpression of ADAM12 accelerates tumor progression in a mouse model of breast cancer (PyMT). In the present study, we found...... that ADAM12 deficiency reduces breast tumor progression in the PyMT model. However, the catalytic activity of ADAM12 appears to be dispensable for its tumor-promoting effect. Interestingly, we demonstrate that ADAM12 endogenously expressed in tumor-associated stroma in the PyMT model does not influence...... tumor progression, but that ADAM12 expression by tumor cells is necessary for tumor progression in these mice. This finding is consistent with our observation that in human breast carcinoma ADAM12 is almost exclusively located in tumor cells and only rarely seen in the tumor-associated stroma. We...

  17. Shale gas produced water treatment using innovative microbial capacitive desalination cell

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, Zachary A. [New Mexico State University, Las Cruces, NM 88003 (United States); Forrestal, Casey [University of Colorado Boulder, Boulder, CO 80309 (United States); Ren, Zhiyong Jason, E-mail: jason.ren@colorado.edu [University of Colorado Boulder, Boulder, CO 80309 (United States); Xu, Pei, E-mail: wxpei@hotmail.com [New Mexico State University, Las Cruces, NM 88003 (United States)

    2015-02-11

    Highlights: • Actual shale gas produced water was treated with no external energy input. • Biodegradation of organics generated stable voltages for desalination. • On average, 36 mg TDS per g activated carbon was removed in 1 h. • A maximum organic removal rate of 6.4 mg DOC per hour was achieved in the reactor. - Abstract: The rapid development of unconventional oil and gas production has generated large amounts of wastewater for disposal, raising significant environmental and public health concerns. Treatment and beneficial use of produced water presents many challenges due to its high concentrations of petroleum hydrocarbons and salinity. The objectives of this study were to investigate the feasibility of treating actual shale gas produced water using a bioelectrochemical system integrated with capacitive deionization—a microbial capacitive desalination cell (MCDC). Microbial degradation of organic compounds in the anode generated an electric potential that drove the desalination of produced water. Sorption and biodegradation resulted in a combined organic removal rate of 6.4 mg dissolved organic carbon per hour in the reactor, and the MCDC removed 36 mg salt per gram of carbon electrode per hour from produced water. This study is a proof-of-concept that the MCDC can be used to combine organic degradation with desalination of contaminated water without external energy input.

  18. Plasticity of Ectomesenchymal Stem Cells and its Ability of Producing Tissue Engineering Tooth by Recombining with Dental Epithelial Cells

    Institute of Scientific and Technical Information of China (English)

    Yan JIN; Liu-Yu BAO; Yi-Jing WANG; Hui-Xia HE

    2005-01-01

    @@ 1 Introduction Recently, it has been found that human dental pulp stem cells could generate dentin-pulp complex-like structures in nude mice, but studies on tissue engineering tooth-like structures by cultured human dental epithelial and mesenchymal stem cells are still reported rarely. Ectomesenchyme is an unique structure of vertebrates embryo compose of postmigratory cephalic neural crest cells(NCC) and its derivatives. The aim of the present study was to identify and isolate the ectomesenchymal stem cells(EMSC) and to demonstrate that EMSCs have the ability of plasticity both in vivo and in vitro. The further interesting was to evaluate the role of EMSC in producing of a tissue engineering tooth together with odontogenic epithelium.

  19. Evaluation of Annealing Treatments for Producing Si-Rich Fuel/Matrix Interaction Layers in Low-Enriched U-Mo Dispersion Fuel Plates Rolled at a Low Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Nicolas E. Woolstenhulme

    2010-06-01

    During fabrication of U-7Mo dispersion fuels, exposure to relatively high temperatures affects the final microstructure of a fuel plate before it is inserted into a reactor. One impact of this high temperature exposure is a chemical interaction that can occur between dissimilar materials. For U-7Mo dispersion fuels, the U-7Mo particles will interact to some extent with the Al or Al alloy matrix to produce interaction products. It has been observed that the final irradiation behavior of a fuel plate can depend on the amount of interaction that occurs at the U-7Mo/matrix interface during fabrication, along with the type of phases that develop at this interface. For the case where a U-7Mo dispersion fuel has a Si-containing Al alloy matrix and is rolled at around 500°C, a Si-rich interaction product has been observed to form that can potentially have a positive impact on fuel performance during irradiation. This interaction product can exhibit stable irradiation behavior and it can act as a diffusion barrier to additional U-Mo/matrix interaction during irradiation. However, for U-7Mo dispersion fuels with softer claddings that are rolled at lower temperatures (e.g., near 425°C), a significant interaction layer has not been observed to form. As a result, the bulk of any interaction layer that develops in these fuels happens during irradiation, and the layer that forms may not exhibit as stable a behavior as one that is formed during fabrication. Therefore, it may be beneficial to add a heat treatment step during the fabrication of dispersion fuel plates with softer cladding alloys that will result in the formation of a uniform, Si-rich interaction layer that is a few microns thick around the U-Mo fuel particles. This type of layer would have characteristics like the one that has been observed in dispersion fuel plates with AA6061 cladding that are fabricated at 500°C, which may exhibit increased stability during irradiation. This report discusses the result of

  20. Mesenchymal stem cells derived in vitro transdifferentiated insulin-producing cells: A new approach to treat type 1 diabetes

    Directory of Open Access Journals (Sweden)

    Shruti Dave

    2014-01-01

    Full Text Available The pathophysiology of type 1 diabetes mellitus (T1DM is largely related to an innate defect in the immune system culminating in a loss of self-tolerance and destruction of the insulin-producing β-cells. Currently, there is no definitive cure for T1DM. Insulin injection does not mimic the precise regulation of β-cells on glucose homeostasis, leading long term to the development of complications. Stem cell therapy is a promising approach and specifically mesenchymal stem cells (MSCs offer a promising possibility that deserves to be explored further. MSCs are multipotent, nonhematopoietic progenitors. They have been explored as an treatment option in tissue regeneration as well as potential of in vitro transdifferentiation into insulin-secreting cells. Thus, the major therapeutic goals for T1DM have been achieved in this way. The regenerative capabilities of MSCs have been a driving force to initiate studies testing their therapeutic effectiveness; their immunomodulatory properties have been equally exciting; which would appear capable of disabling immune dysregulation that leads to β-cell destruction in T1DM. Furthermore, MSCs can be cultured under specially defined conditions, their transdifferentiation can be directed toward the β-cell phenotype, and the formation of insulin-producing cells (IPCs can be targeted. To date, the role of MSCs-derived IPC in T1DM-a unique approach with some positive findings-have been unexplored, but it is still in its very early phase. In this study, a new approach of MSCs-derived IPCs, as a potential therapeutic benefit for T1DM in experimental animal models as well as in humans has been summarized.

  1. License plate detection algorithm

    Science.gov (United States)

    Broitman, Michael; Klopovsky, Yuri; Silinskis, Normunds

    2013-12-01

    A novel algorithm for vehicle license plates localization is proposed. The algorithm is based on pixel intensity transition gradient analysis. Near to 2500 natural-scene gray-level vehicle images of different backgrounds and ambient illumination was tested. The best set of algorithm's parameters produces detection rate up to 0.94. Taking into account abnormal camera location during our tests and therefore geometrical distortion and troubles from trees this result could be considered as passable. Correlation between source data, such as license Plate dimensions and texture, cameras location and others, and parameters of algorithm were also defined.

  2. New strategies to produce and detect singlet oxygen in a cell

    DEFF Research Database (Denmark)

    Gollmer, Anita

    2012-01-01

    Singlet oxygen, the first excited electronic state of molecular oxygen, plays a major role in oxygen-dependent photo-induced cell death. In such systems, singlet oxygen is generally produced in a photosensitized process wherein light is absorbed by a molecule (the so-called sensitizer) which...... of the general methodology to generate and detect singlet oxygen is currently of great importance in order to better understand the roles played by singlet oxygen in photo-induced cell death. From a mechanistic perspective, experiments performed at the level of a single cell provide unique insight...... of a new, commercially available fluorescent probe called Singlet Oxygen Sensor Green® (SOSG) was examined in this dissertation. The pertinent methodology involves a trapping reaction with singlet oxygen that in turn changes the fluorescence quantum yield of the probe. First, it is shown that the immediate...

  3. Interleukin-5-producing group 2 innate lymphoid cells control eosinophilia induced by interleukin-2 therapy.

    Science.gov (United States)

    Van Gool, Frédéric; Molofsky, Ari B; Morar, Malika M; Rosenzwajg, Michelle; Liang, Hong-Erh; Klatzmann, David; Locksley, Richard M; Bluestone, Jeffrey A

    2014-12-04

    Interleukin (IL)-2 promotes regulatory T-cell development and function, and treatment with IL-2 is being tested as therapy for some autoimmune diseases. However, patients receiving IL-2 treatment also experience eosinophilia due to an unknown mechanism. Here, we show that patients receiving low-dose IL-2 have elevated levels of serum IL-5, and this correlates with their degree of eosinophilia. In mice, low-dose IL-2-anti-IL-2 antibody complexes drove group 2 innate lymphoid cells (ILC2) to produce IL-5 and proliferate. Using genetic approaches in mice, we demonstrate that activation of ILC2 was responsible for the eosinophilia observed with IL-2 therapy. These observations reveal a novel cellular network that is activated during IL-2 treatment. A better understanding of the cross talk between these cell populations may lead to more effective targeting of IL-2 to treat autoimmune disease. © 2014 by The American Society of Hematology.

  4. Polymorphous silicon thin films produced in dusty plasmas: application to solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Roca i Cabarrocas, Pere; Chaabane, N; Kharchenko, A V; Tchakarov, S [Laboratoire de Physique des Interfaces et des Couches Minces (UMR 7647), Ecole Polytechnique, 91128 Palaiseau Cedex (France)

    2004-12-01

    We summarize our current understanding of the optimization of PIN solar cells produced by plasma enhanced chemical vapour deposition from silane-hydrogen mixtures. To increase the deposition rate, the discharge is operated under plasma conditions close to powder formation, where silicon nanocrystals contribute to the deposition of so-called polymorphous silicon thin films. We show that the increase in deposition rate can be achieved via an accurate control of the plasma parameters. However, this also results in a highly defective interface in the solar cells due to the bombardment of the P-layer by positively charged nanocrystals during the deposition of the I-layer. We show that decreasing the ion energy by increasing the total pressure or by using silane-helium mixtures allows us to increase both the deposition rate and the solar cells efficiency, as required for cost effective thin film photovoltaics.

  5. Polymorphous silicon thin films produced in dusty plasmas: application to solar cells

    Science.gov (United States)

    Cabarrocas, Pere Roca i.; Chaâbane, N.; Kharchenko, A. V.; Tchakarov, S.

    2004-12-01

    We summarize our current understanding of the optimization of PIN solar cells produced by plasma enhanced chemical vapour deposition from silane hydrogen mixtures. To increase the deposition rate, the discharge is operated under plasma conditions close to powder formation, where silicon nanocrystals contribute to the deposition of so-called polymorphous silicon thin films. We show that the increase in deposition rate can be achieved via an accurate control of the plasma parameters. However, this also results in a highly defective interface in the solar cells due to the bombardment of the P-layer by positively charged nanocrystals during the deposition of the I-layer. We show that decreasing the ion energy by increasing the total pressure or by using silane helium mixtures allows us to increase both the deposition rate and the solar cells efficiency, as required for cost effective thin film photovoltaics.

  6. Analysis of human and mouse reprogramming of somatic cells to induced pluripotent stem cells. What is in the plate?

    Directory of Open Access Journals (Sweden)

    Stéphanie Boué

    Full Text Available After the hope and controversy brought by embryonic stem cells two decades ago for regenerative medicine, a new turn has been taken in pluripotent cells research when, in 2006, Yamanaka's group reported the reprogramming of fibroblasts to pluripotent cells with the transfection of only four transcription factors. Since then many researchers have managed to reprogram somatic cells from diverse origins into pluripotent cells, though the cellular and genetic consequences of reprogramming remain largely unknown. Furthermore, it is still unclear whether induced pluripotent stem cells (iPSCs are truly functionally equivalent to embryonic stem cells (ESCs and if they demonstrate the same differentiation potential as ESCs. There are a large number of reprogramming experiments published so far encompassing genome-wide transcriptional profiling of the cells of origin, the iPSCs and ESCs, which are used as standards of pluripotent cells and allow us to provide here an in-depth analysis of transcriptional profiles of human and mouse cells before and after reprogramming. When compared to ESCs, iPSCs, as expected, share a common pluripotency/self-renewal network. Perhaps more importantly, they also show differences in the expression of some genes. We concentrated our efforts on the study of bivalent domain-containing genes (in ESCs which are not expressed in ESCs, as they are supposedly important for differentiation and should possess a poised status in pluripotent cells, i.e. be ready to but not yet be expressed. We studied each iPSC line separately to estimate the quality of the reprogramming and saw a correlation of the lowest number of such genes expressed in each respective iPSC line with the stringency of the pluripotency test achieved by the line. We propose that the study of expression of bivalent domain-containing genes, which are normally silenced in ESCs, gives a valuable indication of the quality of the iPSC line, and could be used to select the

  7. Combinatorial plasma polymerization approach to produce thin films for testing cell proliferation.

    Science.gov (United States)

    Antonini, V; Torrengo, S; Marocchi, L; Minati, L; Dalla Serra, M; Bao, G; Speranza, G

    2014-01-01

    Plasma enhanced physical vapor depositions are extensively used to fabricate substrates for cell culture applications. One peculiarity of the plasma processes is the possibility to deposit thin films with reproducible chemical and physical properties. In the present work, a combinatorial plasma polymerization process was used to deposit thin carbon based films to promote cell adhesion, in the interest of testing cell proliferation as a function of the substrate chemical properties. Peculiarity of the combinatorial approach is the possibility to produce in just one deposition experiment, a set of surfaces of varying chemical moieties by changing the precursor composition. A full characterization of the chemical, physical and thermodynamic properties was performed for each set of the synthesized surfaces. X-ray photoelectron spectroscopy was used to measure the concentration of carboxyl, hydroxyl and amine functional groups on the substrate surfaces. A perfect linear trend between polar groups' density and precursors' concentration was found. Further analyses reveled that also contact angles and the correspondent surface energies of all deposited thin films are linearly dependent on the precursor concentration. To test the influence of the surface composition on the cell adhesion and proliferation, two cancer cell lines were utilized. The cell viability was assessed after 24 h and 48 h of cell culture. Experiments show that we are able to control the cell adhesion and proliferation by properly changing the thin film deposition conditions i.e. the concentration and the kind of chemical moiety on the substrate surface. The results also highlight that physical and chemical factors of biomaterial surface, including surface hydrophobicity and free energy, chemical composition, and topography, can altered cell attachment.

  8. Canine Prostate Cancer Cell Line (Probasco) Produces Osteoblastic Metastases In Vivo

    Science.gov (United States)

    Simmons, Jessica K.; Dirksen, Wessel P.; Hildreth, Blake E.; Dorr, Carlee; Williams, Christina; Thomas, Rachael; Breen, Matthew; Toribio, Ramiro E.; Rosol, Thomas J.

    2014-01-01

    BACKGROUND In 2012, over 240,000 men were diagnosed with prostate cancer and over 28,000 died from the disease. Animal models of prostate cancer are vital to understanding its pathogenesis and developing therapeutics. Canine models in particular are useful due to their similarities to late-stage, castration-resistant human disease with osteoblastic bone metastases. This study established and characterized a novel canine prostate cancer cell line that will contribute to the understanding of prostate cancer pathogenesis. METHODS A novel cell line (Probasco) was derived from a mixed breed dog that had spontaneous prostate cancer. Cell proliferation and motility were analyzed in vitro. Tumor growth in vivo was studied by subcutaneous, intratibial, and intracardiac injection of Probasco cells into nude mice. Tumors were evaluated by bioluminescent imaging, Faxitron radiography, µCT, and histology. RT-PCR and genome-wide DNA copy number profiling were used to characterize the cell line. RESULTS The Probasco cells grew in vitro (over 75 passages) and were tumorigenic in nude mice. Probasco cells expressed high levels of BMP2, CDH1, MYOF, FOLH1, RUNX2, and SMAD5 modest CXCL12, SLUG, and BMP, and no PTHrP mRNA. Following intracardiac injection, Probasco cells metastasized primarily to the appendicular skeleton, and both intratibial and intracardiac injections produced osteoblastic tumors in bone. Comparative genomic hybridization demonstrated numerous DNA copy number aberrations throughout the genome, including large losses and gains in multiple chromosomes. CONCLUSIONS The Probasco prostate cancer cell line will be a valuable model to investigate the mechanisms of prostate cancer pathogenesis and osteoblastic bone metastases. PMID:25043424

  9. Vaccination Produces CD4 T Cells with a Novel CD154-CD40-Dependent Cytolytic Mechanism.

    Science.gov (United States)

    Coler, Rhea N; Hudson, Thomas; Hughes, Sean; Huang, Po-Wei D; Beebe, Elyse A; Orr, Mark T

    2015-10-01

    The discovery of new vaccines against infectious diseases and cancer requires the development of novel adjuvants with well-defined activities. The TLR4 agonist adjuvant GLA-SE elicits robust Th1 responses to a variety of vaccine Ags and is in clinical development for both infectious diseases and cancer. We demonstrate that immunization with a recombinant protein Ag and GLA-SE also induces granzyme A expression in CD4 T cells and produces cytolytic cells that can be detected in vivo. Surprisingly, these in vivo CTLs were CD4 T cells, not CD8 T cells, and this cytolytic activity was not dependent on granzyme A/B or perforin. Unlike previously reported CD4 CTLs, the transcription factors Tbet and Eomes were not necessary for their development. CTL activity was also independent of the Fas ligand-Fas, TRAIL-DR5, and canonical death pathways, indicating a novel mechanism of CTL activity. Rather, the in vivo CD4 CTL activity induced by vaccination required T cell expression of CD154 (CD40L) and target cell expression of CD40. Thus, vaccination with a TLR4 agonist adjuvant induces CD4 CTLs, which kill through a previously unknown CD154-dependent mechanism. Copyright © 2015 by The American Association of Immunologists, Inc.

  10. Atypical and classical memory B cells produce Plasmodium falciparum neutralizing antibodies

    DEFF Research Database (Denmark)

    Muellenbeck, Matthias F; Ueberheide, Beatrix; Amulic, Borko

    2013-01-01

    Antibodies can protect from Plasmodium falciparum (Pf) infection and clinical malaria disease. However, in the absence of constant reexposure, serum immunoglobulin (Ig) levels rapidly decline and full protection from clinical symptoms is lost, suggesting that B cell memory is functionally impaire...... that constant immune activation rather than impaired memory function leads to the accumulation of AtM in malaria. Understanding the memory B cell response to natural Pf infection may be key to the development of a malaria vaccine that induces long-lived protection.......Antibodies can protect from Plasmodium falciparum (Pf) infection and clinical malaria disease. However, in the absence of constant reexposure, serum immunoglobulin (Ig) levels rapidly decline and full protection from clinical symptoms is lost, suggesting that B cell memory is functionally impaired....... We show at the single cell level that natural Pf infection induces the development of classical memory B cells (CM) and atypical memory B cells (AtM) that produce broadly neutralizing antibodies against blood stage Pf parasites. CM and AtM contribute to anti-Pf serum IgG production, but only AtM show...

  11. CCR2 defines in vivo development and homing of IL-23-driven GM-CSF-producing Th17 cells.

    Science.gov (United States)

    Kara, Ervin E; McKenzie, Duncan R; Bastow, Cameron R; Gregor, Carly E; Fenix, Kevin A; Ogunniyi, Abiodun D; Paton, James C; Mack, Matthias; Pombal, Diana R; Seillet, Cyrill; Dubois, Bénédicte; Liston, Adrian; MacDonald, Kelli P A; Belz, Gabrielle T; Smyth, Mark J; Hill, Geoffrey R; Comerford, Iain; McColl, Shaun R

    2015-10-29

    IL-17-producing helper T (Th17) cells are critical for host defense against extracellular pathogens but also drive numerous autoimmune diseases. Th17 cells that differ in their inflammatory potential have been described including IL-10-producing Th17 cells that are weak inducers of inflammation and highly inflammatory, IL-23-driven, GM-CSF/IFNγ-producing Th17 cells. However, their distinct developmental requirements, functions and trafficking mechanisms in vivo remain poorly understood. Here we identify a temporally regulated IL-23-dependent switch from CCR6 to CCR2 usage by developing Th17 cells that is critical for pathogenic Th17 cell-driven inflammation in experimental autoimmune encephalomyelitis (EAE). This switch defines a unique in vivo cell surface signature (CCR6(-)CCR2(+)) of GM-CSF/IFNγ-producing Th17 cells in EAE and experimental persistent extracellular bacterial infection, and in humans. Using this signature, we identify an IL-23/IL-1/IFNγ/TNFα/T-bet/Eomesodermin-driven circuit driving GM-CSF/IFNγ-producing Th17 cell formation in vivo. Thus, our data identify a unique cell surface signature, trafficking mechanism and T-cell intrinsic regulators of GM-CSF/IFNγ-producing Th17 cells.

  12. A cell-free microtiter plate screen for improved [FeFe] hydrogenases.

    Directory of Open Access Journals (Sweden)

    James A Stapleton

    Full Text Available BACKGROUND: [FeFe] hydrogenase enzymes catalyze the production and dissociation of H(2, a potential renewable fuel. Attempts to exploit these catalysts in engineered systems have been hindered by the biotechnologically inconvenient properties of the natural enzymes, including their extreme oxygen sensitivity. Directed evolution has been used to improve the characteristics of a range of natural catalysts, but has been largely unsuccessful for [FeFe] hydrogenases because of a lack of convenient screening platforms. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe an in vitro screening technology for oxygen-tolerant and highly active [FeFe] hydrogenases. Despite the complexity of the protocol, we demonstrate a level of reproducibility that allows moderately improved mutants to be isolated. We have used the platform to identify a mutant of the Chlamydomonas reinhardtii [FeFe] hydrogenase HydA1 with a specific activity approximately 4 times that of the wild-type enzyme. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate the feasibility of using the screen presented here for large-scale efforts to identify improved biocatalysts for energy applications. The system is based on our ability to activate these complex enzymes in E. coli cell extracts, which allows unhindered access to the protein maturation and assay environment.

  13. Electrical conductivity modeling of multiple carbon fillers in liquid crystal polymer composites for fuel cell bipolar plate applications

    Energy Technology Data Exchange (ETDEWEB)

    Barton, R.L.; Keith, J.M.; King, J.A. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Chemical Engineering

    2008-08-15

    This study modelled the electrical conductivity of a single filler composite system using a general effective media (GEM) equation. The aim of the study was to investigate the use of synthetic graphite and carbon fiber in liquid crystal polymers for fuel cell bipolar plate applications. The polymer consisted of 73 mole per cent hydroxybenzoic acid and 27 mole per cent hydroxynaphthoic acid. Composites of various concentrations of single and multiple filler combinations were tested. A volumetric in-plane electrical conductivity test was conducted on all samples in order to measure voltage drop. A through-plane conductivity test was conducted to measure resistivity. The GEM equation was then used to model the conductivity data obtained during the tests. Results of the study showed that at 45 vol per cent, the electrical conductivity of the multiple filler composite was comparable to data obtained from single filler electrical conductivities. The electrical conductivity of the multiple filler composite at 60 per cent graphite and 10 per cent carbon fiber was comparable to the single filler carbon fiber composite, but lower than the single filler synthetic graphite composite. Results also showed that the GEM equation provided excellent agreement with results obtained during the experiments. It was concluded that the percolation threshold of the multiple filler composite was almost identical to the single carbon fiber filler, but lower than the single synthetic graphite composite. 35 refs., 3 tabs., 2 figs.

  14. Electrical properties of carbon-based polypropylene composites for bipolar plates in polymer electrolyte membrane fuel cell (PEMFC)

    Science.gov (United States)

    Dweiri, Radwan; Sahari, Jaafar

    An investigation is made of the electrical properties of polypropylene/graphite (PP/G) composites as prospective replacements for the traditional graphite bipolar plate in proton-exchange membrane fuel cells. The composites have relatively low electrical conductivities, i.e., up to 28 S cm -1 at 90 wt.% G. Combination of G with carbon black (CB) is an effective way to develop higher conductivity composites. The conductivity reaches 35 S cm -1 by combination of 25 wt.% CB and 55 wt.% G to 20 wt.% PP. This is five times the value at 80 wt.% G and 20 wt.% PP (7 S cm -1). Two methods are mainly adopted for the preparation of composites, namely, melt compounding and solution blending. Solution blending of PP with conductive fillers followed by moulding of the dried powder leads to higher conductivities compared with those of melt-compounded composites. The combination of conjugated conducting polymers such as polyaniline (PANi) with the PP, G, and CB is also investigated. It is found that composites containing PANi have lower conductivities than those of the neat composites. This decrease in conductivity is attributed to the poor thermal stability of PANi.

  15. Mini-FLOTAC for counting Toxoplasma gondii oocysts from cat feces--comparison with cell counting plates.

    Science.gov (United States)

    Djokic, Vitomir; Blaga, Radu; Rinaldi, Laura; Le Roux, Delphine; Ducry, Tamara; Maurelli, Maria Paola; Perret, Catherine; Djurkovic Djakovic, Olgica; Cringoli, Giuseppe; Boireau, Pascal

    2014-12-01

    Oocysts of Toxoplasma gondii represent one of the most common environmental contaminants causing the zoonotic infection toxoplasmosis. The aim of the present study was to compare the Mini-FLOTAC device with traditional cell counting plates (Kova Slide) for the detection of T. gondii oocysts from feline feces. Two types of experiments were performed: (i) purified oocysts were counted in different dilutions and (ii) specific pathogen free T. gondii-negative cat feces was inoculated with numbers of purified oocysts and counting was performed directly from feces. Our analysis showed a thousand times higher sensitivity of Mini-FLOTAC (5 × 10(2) oocysts) compared to Kova Slide (5 × 10(5) oocysts). Also, when compared by McNemar's test, counting of the purified oocysts showed a higher sensitivity of Mini-FLOTAC compared to Kova Slide, for a dilution of 10(3) oocysts/ml (chi(2) = 6.1; P microscopes in any laboratory or field conditions. We therefore recommend its use for regular screening. Further studies are needed to validate Mini-FLOTAC for the detection of oocysts in soil and water samples in field conditions.

  16. Drinking water purification by electrosynthesis of hydrogen peroxide in a power-producing PEM fuel cell.

    Science.gov (United States)

    Li, Winton; Bonakdarpour, Arman; Gyenge, Előd; Wilkinson, David P

    2013-11-01

    The industrial anthraquinone auto-oxidation process produces most of the world's supply of hydrogen peroxide. For applications that require small amounts of H2 O2 or have economically difficult transportation means, an alternate, on-site H2 O2 production method is needed. Advanced drinking water purification technologies use neutral-pH H2 O2 in combination with UV treatment to reach the desired water purity targets. To produce neutral H2 O2 on-site and on-demand for drinking water purification, the electroreduction of oxygen at the cathode of a proton exchange membrane (PEM) fuel cell operated in either electrolysis (power consuming) or fuel cell (power generating) mode could be a possible solution. The work presented here focuses on the H2 /O2 fuel cell mode to produce H2 O2 . The fuel cell reactor is operated with a continuous flow of carrier water through the cathode to remove the product H2 O2 . The impact of the cobalt-carbon composite cathode catalyst loading, Teflon content in the cathode gas diffusion layer, and cathode carrier water flowrate on the production of H2 O2 are examined. H2 O2 production rates of up to 200 μmol h(-1)  cmgeometric (-2) are achieved using a continuous flow of carrier water operating at 30 % current efficiency. Operation times of more than 24 h have shown consistent H2 O2 and power production, with no degradation of the cobalt catalyst.

  17. Human iPS cell-derived insulin producing cells form vascularized organoids under the kidney capsules of diabetic mice.

    Directory of Open Access Journals (Sweden)

    Sudhanshu P Raikwar

    Full Text Available Type 1 diabetes (T1D is caused by autoimmune disease that leads to the destruction of pancreatic β-cells. Transplantation of cadaveric pancreatic organs or pancreatic islets can restore normal physiology. However, there is a chronic shortage of cadaveric organs, limiting the treatment of the majority of patients on the pancreas transplantation waiting list. Here, we hypothesized that human iPS cells can be directly differentiated into insulin producing cells (IPCs capable of secreting insulin. Using a series of pancreatic growth factors, we successfully generated iPS cells derived IPCs. Furthermore, to investigate the capability of these cells to secrete insulin in vivo, the differentiated cells were transplanted under the kidney capsules of diabetic immunodeficient mice. Serum glucose levels gradually declined to either normal or near normal levels over 150 days, suggesting that the IPCs were secreting insulin. In addition, using MRI, a 3D organoid appeared as a white patch on the transplanted kidneys but not on the control kidneys. These organoids showed neo-vascularization and stained positive for insulin and glucagon. All together, these data show that a pancreatic organ can be created in vivo providing evidence that iPS cells might be a novel option for the treatment of T1D.

  18. Understanding Transcriptional Enhancement in Monoclonal Antibody-Producing Chinese Hamster Ovary Cells

    Science.gov (United States)

    Nicoletti, Sarah E.

    With the demand for monoclonal antibody (mAB) therapeutics continually increasing, the need to better understand what makes a high productivity clone has gained substantial interest. Monoclonal antibody producing Chinese hamster ovary (CHO) cells with different productivities were provided by a biopharmaceutical company for investigation. Gene copy numbers, mRNA levels, and mAb productivities were previously determined for two low producing clones and their amplified progeny. These results showed an increase in mRNA copy number in amplified clones, which correlated to the observed increases in specific productivity of these clones. The presence of multiple copies of mRNA per one copy of DNA in the higher productivity clones has been coined as transcriptional enhancement. The methylation status of the CMV promoter as well as transcription factor/promoter interactions were evaluated to determine the cause of transcriptional enhancement. Methylation analysis via bisulfite sequencing revealed no significant difference in overall methylation status of the CMV promoter. These data did, however, reveal the possibility of differential interactions of transcription factors between the high and low productivity cell clones. This finding was further supported by chromatin immunoprecipitations previously performed in the lab, as well as literature studies. Transcription activator-like effector (TALE) binding proteins were constructed and utilized to selectively immunoprecipitate the CMV promoter along with its associated transcription factors in the different CHO cell clones. Cells were transfected with the TALE proteins, harvested and subjected to a ChIP-like procedure. Results obtained from the TALE ChIP demonstrated the lack of binding of the protein to the promoter and the need to redesign the TALE. Overall, results obtained from this study were unable to give a clear indication as to the causes of transcriptional enhancement in the amplified CHO cell clones. Further

  19. Completely ES cell-derived mice produced by tetraploid complementation using inner cell mass (ICM) deficient blastocysts.

    Science.gov (United States)

    Wen, Duancheng; Saiz, Nestor; Rosenwaks, Zev; Hadjantonakis, Anna-Katerina; Rafii, Shahin

    2014-01-01

    Tetraploid complementation is often used to produce mice from embryonic stem cells (ESCs) by injection of diploid (2n) ESCs into tetraploid (4n) blastocysts (ESC-derived mice). This method has also been adapted to mouse cloning and the derivation of mice from induced pluripotent stem (iPS) cells. However, the underlying mechanism(s) of the tetraploid complementation remains largely unclear. Whether this approach can give rise to completely ES cell-derived mice is an open question, and has not yet been unambiguously proven. Here, we show that mouse tetraploid blastocysts can be classified into two groups, according to the presence or absence of an inner cell mass (ICM). We designate these as type a (presence of ICM at blastocyst stage) or type b (absence of ICM). ESC lines were readily derived from type a blastocysts, suggesting that these embryos retain a pluripotent epiblast compartment; whereas the type b blastocysts possessed very low potential to give rise to ESC lines, suggesting that they had lost the pluripotent epiblast. When the type a blastocysts were used for tetraploid complementation, some of the resulting mice were found to be 2n/4n chimeric; whereas when type b blastocysts were used as hosts, the resulting mice are all completely ES cell-derived, with the newborn pups displaying a high frequency of abdominal hernias. Our results demonstrate that completely ES cell-derived mice can be produced using ICM-deficient 4n blastocysts, and provide evidence that the exclusion of tetraploid cells from the fetus in 2n/4n chimeras can largely be attributed to the formation of ICM-deficient blastocysts.

  20. Completely ES cell-derived mice produced by tetraploid complementation using inner cell mass (ICM deficient blastocysts.

    Directory of Open Access Journals (Sweden)

    Duancheng Wen

    Full Text Available Tetraploid complementation is often used to produce mice from embryonic stem cells (ESCs by injection of diploid (2n ESCs into tetraploid (4n blastocysts (ESC-derived mice. This method has also been adapted to mouse cloning and the derivation of mice from induced pluripotent stem (iPS cells. However, the underlying mechanism(s of the tetraploid complementation remains largely unclear. Whether this approach can give rise to completely ES cell-derived mice is an open question, and has not yet been unambiguously proven. Here, we show that mouse tetraploid blastocysts can be classified into two groups, according to the presence or absence of an inner cell mass (ICM. We designate these as type a (presence of ICM at blastocyst stage or type b (absence of ICM. ESC lines were readily derived from type a blastocysts, suggesting that these embryos retain a pluripotent epiblast compartment; whereas the type b blastocysts possessed very low potential to give rise to ESC lines, suggesting that they had lost the pluripotent epiblast. When the type a blastocysts were used for tetraploid complementation, some of the resulting mice were found to be 2n/4n chimeric; whereas when type b blastocysts were used as hosts, the resulting mice are all completely ES cell-derived, with the newborn pups displaying a high frequency of abdominal hernias. Our results demonstrate that completely ES cell-derived mice can be produced using ICM-deficient 4n blastocysts, and provide evidence that the exclusion of tetraploid cells from the fetus in 2n/4n chimeras can largely be attributed to the formation of ICM-deficient blastocysts.

  1. Bone invading NSCLC cells produce IL-7: mice model and human histologic data

    Directory of Open Access Journals (Sweden)

    Quarto Rodolfo

    2010-01-01

    Full Text Available Abstract Background Bone metastases are a common and dismal consequence of lung cancer that is a leading cause of death. The role of IL-7 in promoting bone metastases has been previously investigated in NSCLC, but many aspects remain to be disclosed. To further study IL-7 function in bone metastasis, we developed a human-in-mice model of bone aggression by NSCLC and analyzed human bone metastasis biopsies. Methods We used NOD/SCID mice implanted with human bone. After bone engraftment, two groups of mice were injected subcutaneously with A549, a human NSCLC cell line, either close or at the contralateral flank to the human bone implant, while a third control group did not receive cancer cells. Tumor and bone vitality and IL-7 expression were assessed in implanted bone, affected or not by A549. Serum IL-7 levels were evaluated by ELISA. IL-7 immunohistochemistry was performed on 10 human bone NSCLC metastasis biopsies for comparison. Results At 12 weeks after bone implant, we observed osteogenic activity and neovascularization, confirming bone vitality. Tumor aggressive cells implanted close to human bone invaded the bone tissue. The bone-aggressive cancer cells were positive for IL-7 staining both in the mice model and in human biopsies. Higher IL-7 serum levels were found in mice injected with A549 cells close to the bone implant compared to mice injected with A549 cells in the flank opposite to the bone implant. Conclusions We demonstrated that bone-invading cells express and produce IL-7, which is known to promote osteoclast activation and osteolytic lesions. Tumor-bone interaction increases IL-7 production, with an increase in IL-7 serum levels. The presented mice model of bone invasion by contiguous tumor is suitable to study bone-tumor cell interaction. IL-7 plays a role in the first steps of metastatic process.

  2. HCN Producing Bacteria Enable Sensing Of Non-Bioavailable Hg Species by the Whole Cell Biosensor

    Science.gov (United States)

    Horvat, M.; Rijavec, T.; Koron, N.; Lapanje, A.

    2015-12-01

    Bacteria play an important role in Hg transformation reactions. The production of cyanide (HCN) and other secondary metabolites seems to be key elements involved in these transformations. Current hypotheses link the role of HCN production to growth inhibition of nonHCN producing competitor organisms (role of an antimicrobial agent). Our past investigations showed that HCN production did not correlate with antimicrobial activity and since pK value of HCN is very high (pK = 9,21), it can be expected that most of the produced HCN is removed from the microenvironment. This way, the expected inhibitory concentrations can hardly be reached. Accordingly, we proposed a new concept, where the ability of complexation of transient metals by HCN served as a regulation process for the accessibility of micro-elements. In our study, we focused on the presence of HCN producing bacteria and carried it out in the Hg contaminated environment connected to the Idrija Mercury Mine, Slovenia. We characterised the isolates according to the presence of Hg resistance (HgR), level of HCN production and genetic similarities. In laboratory setups, using our merR whole cell based biosensor, we determined the transformation of low bioavailable Hg0 and HgS forms into bioavailable Hg by these HCN producing bacteria. We observed that HgR strains producing HCN had the highest impact on increased Hg bioavailability. In the proposed ecological strategy HgR HCN producing bacteria increase their competitive edge over non-HgR competitors through the increase of Hg toxicity. Due to their activity, Hg is made available to other organisms as well and thus enters into the ecosystem. Finally, using some of the characteristics of bacteria (e.g. Hg resistance genetic elements), we developed a fully automated sensing approach, combining biosensorics and mechatronics, to measure the bioavailability of Hg in situ.

  3. Impact of alginate-producing Pseudomonas aeruginosa on alveolar macrophage apoptotic cell clearance.

    Science.gov (United States)

    McCaslin, Charles A; Petrusca, Daniela N; Poirier, Christophe; Serban, Karina A; Anderson, Gregory G; Petrache, Irina

    2015-01-01

    Pseudomonas aeruginosa infection is a hallmark of lung disease in cystic fibrosis. Acute infection with P. aeruginosa profoundly inhibits alveolar macrophage clearance of apoptotic cells (efferocytosis) via direct effect of virulence factors. During chronic infection, P. aeruginosa evades host defense by decreased virulence, which includes the production or, in the case of mucoidy, overproduction of alginate. The impact of alginate on innate immunity, in particular on macrophage clearance of apoptotic cells is not known. We hypothesized that P. aeruginosa strains that exhibit reduced virulence impair macrophage clearance of apoptotic cells and we investigated if the polysaccharide alginate produced by mucoid P. aeruginosa is sufficient to inhibit alveolar macrophage efferocytosis. Rat alveolar or human peripheral blood monocyte (THP-1)-derived macrophage cell lines were exposed in vitro to exogenous alginate or to wild type or alginate-overproducing mucoid P. aeruginosa prior to challenge with apoptotic human Jurkat T-lymphocytes. The importance of LPS contamination and that of structural integrity of alginate polymers was tested using alginate of different purities and alginate lyase, respectively. Alginate inhibited alveolar macrophage efferocytosis in a dose- and time-dependent manner. This effect was augmented but not exclusively attributed to lipopolysaccharide (LPS) present in alginates. Alginate-producing P. aeruginosa inhibited macrophage efferocytosis by more than 50%. A mannuronic-specific alginate lyase did not restore efferocytosis inhibited by exogenous guluronic-rich marine alginate, but had a marked beneficial effect on efferocytosis of alveolar macrophages exposed to mucoid P. aeruginosa. Despite decreased virulence, mucoid P. aeruginosa may contribute to chronic airway inflammation through significant inhibition of alveolar clearance of apoptotic cells and debris. The mechanism by which mucoid bacteria inhibit efferocytosis may involve alginate

  4. A cloned toy poodle produced from somatic cells derived from an aged female dog.

    Science.gov (United States)

    Jang, G; Hong, S G; Oh, H J; Kim, M K; Park, J E; Kim, H J; Kim, D Y; Lee, B C

    2008-03-15

    To date, dogs have been cloned with somatic cell nuclear transfer (SCNT), using donor cells derived from large-breed dogs 2 months to 3 years of age. The objective of the present study was to use SCNT to produce a small-breed dog from ear fibroblasts of an aged poodle, using large-breed oocyte donors and surrogate females, and to determine the origin of its mitochondrial DNA (mtDNA) and the length of its telomeres. Oocytes were derived from large-breed donors, matured in vivo, collected by flushing oviducts, and reconstructed with somatic cells derived from an aged (14-year-old) female toy poodle. Oocytes and donor cells were fused by electric stimuli, activated chemically, and transferred into the oviducts of large-breed recipient females. Overall, 358 activated couplets were surgically transferred into the oviducts of 20 recipient dogs. Two recipients became pregnant; only one maintained pregnancy to term, and a live puppy (weighing 190 g) was delivered by Caesarean section. The cloned poodle was phenotypically and genetically identical to the nuclear donor dog; however, its mtDNA was from the oocyte donor, and its mean telomere length was not significantly different from that of the nuclear donor. In summary, we demonstrated that a small-breed dog could be cloned by transferring activated couplets produced by fusion of somatic cells from a small-breed, aged donor female with enucleated in-vivo-matured oocytes of large-breed females, and transferred into the oviduct of large-breed recipient female dogs.

  5. Expression System Based on an MTIIa Promoter to Produce hPSA in Mammalian Cell Cultures

    Science.gov (United States)

    Santos, Anderson K.; Parreira, Ricardo C.; Resende, Rodrigo R.

    2016-01-01

    Because of the limitations of standard culture techniques, the development of new recombinant protein expression systems with biotechnological potential is a key challenge. Ideally, such systems should be able to effectively and accurately synthesize a protein of interest with intrinsic metabolic capacity. Here, we describe such a system that was designed based on a plasmid vector containing promoter elements derived from the metallothionein MTIIa promoter, as well as processing and purification elements. This promoter can be induced by heavy metals in a culture medium to induce the synthesis of human prostate-specific antigen (hPSA), which has been modified to insert elements for purification, proteolysis, and secretion. We optimized hPSA production in this system by comparing the effects and contributions of ZnCl2, CdCl2, and CuSO4 in HEK293FT, HeLa, BHK-21, and CHO-K1 cells. We also compared the effectiveness of three different transfection agents: multi-walled carbon nanotubes, Lipofectamine 2000, and X-tremeGENE HP Reagent. hPSA production was confirmed via the detection of enhanced green fluorescent protein fluorescence, and cell viability was determined. The expression of hPSA was compared with that of the native protein produced by LNCaP cells, using enzyme-linked immunosorbent assay and sodium dodecyl sulfate polyacrylamide gel electrophoresis. X-tremeGENE reagent, the BHK-21 cell line, and CuSO4 showed the highest hPSA production rates. Furthermore, BHK-21 cells were more resistant to the oxidative stress caused by 100 μM CuSO4. These results suggest that the proposed optimized inducible expression system can effectively produce recombinant proteins with desired characteristics for a wide range of applications in molecular biology. PMID:27582737

  6. Expression system based on an MTIIa promoter to produce hPSA in mammalian cell cultures

    Directory of Open Access Journals (Sweden)

    Anderson K Santos

    2016-08-01

    Full Text Available Because of the limitations of standard culture techniques, the development of new recombinant protein expression systems with biotechnological potential is a key challenge. Ideally, such systems should be able to effectively and accurately synthesize a protein of interest with intrinsic metabolic capacity. Here, we describe such a system that was designed based on a plasmid vector containing promoter elements derived from the metallothionein MTIIa promoter, as well as processing and purification elements. This promoter can be induced by heavy metals in a culture medium to induce the synthesis of human prostate-specific antigen (hPSA, which has been modified to insert elements for purification, proteolysis, and secretion. We optimized hPSA production in this system by comparing the effects and contributions of ZnCl2, CdCl2, and CuSO4 in HEK293FT, HeLa, BHK-21, and CHO-K1 cells. We also compared the effectiveness of three different transfection agents: multi-walled carbon nanotubes, Lipofectamine 2000, and X-tremeGENE HP Reagent. hPSA production was confirmed via the detection of enhanced green fluorescent protein fluorescence, and cell viability was determined. The expression of hPSA was compared with that of the native protein produced by LNCaP cells, using enzyme-linked immunosorbent assay and sodium dodecyl sulphate polyacrylamide gel electrophoresis. X-tremeGENE reagent, the BHK-21 cell line, and CuSO4 showed the highest hPSA production rates. Furthermore, BHK-21 cells were more resistant to the oxidative stress caused by 100 μM CuSO4. These results suggest that the proposed optimized inducible expression system can effectively produce recombinant proteins with desired characteristics for a wide range of applications in molecular biology.

  7. Trans-presentation of IL-15 dictates IFN-producing killer dendritic cells effector functions.

    Science.gov (United States)

    Ullrich, Evelyn; Bonmort, Mathieu; Mignot, Gregoire; Jacobs, Benedikt; Bosisio, Daniela; Sozzani, Silvano; Jalil, Abdelali; Louache, Fawzia; Bulanova, Elena; Geissman, Frederic; Ryffel, Bernard; Chaput, Nathalie; Bulfone-Paus, Silvia; Zitvogel, Laurence

    2008-06-15

    IFN-producing killer dendritic cells (IKDC) were initially described as B220(+)CD11c(+)CD3(-)NK1.1(+) tumor-infiltrating cells that mediated part of the antitumor effects of the combination therapy with imatinib mesylate and IL-2. In this study, we show their functional dependency on IL-15 during homeostasis and inflammatory processes. Trans-presentation of IL-15 by IL-15Ralpha allows dramatic expansion of IKDC in vitro and in vivo, licenses IKDC for TRAIL-dependent killing and endows IKDC with immunizing potential, all three biological attributes not shared by B220(-)NK cells. However, IL-15 down-regulates the capacity of IKDC to induce MHC class I- or II-restricted T cell activation in vitro. Trans-presentation of IL-15 by IL-15Ralpha allows IKDC to respond to TLR3 and TLR4 ligands for the production of CCL2, a chemokine that is critical for IKDC trafficking into tumor beds (as described recently). We conclude that IKDC represent a unique subset of innate effectors functionally distinguishable from conventional NK cells in their ability to promptly respond to IL-15-driven inflammatory processes.

  8. Differentiation of bone marrow-derived mesenchymal stem cells from diabetic patients into insulin-producing cells in vitro

    Institute of Scientific and Technical Information of China (English)

    SUN Yu; LI Hui; WANG Ke-xin; CHEN Li; HOU Xin-guo; HOU Wei-kai; DONG Jian-jun; SUN Lei; TANG Kuan-xiao; WANG Bin; SONG Jun

    2007-01-01

    Bckground Stem cells, which have the ability to differentiate into insulin-producing cells (IPCs), would provide a potentially unlimited source of islet cells for transplantation and alleviate the major limitations of availability and allogeneic rejection. Therefore, the utilization of stem cells is becoming the most promising therapy for diabetes mellitus (DM). Here,we studied the differentiation capacity of the diabetic patient's bone marrow-derived mesenchymal stem cells (MSCs) and tested the feasibility of using MSCs for β-cell replacement.Methods Bone marrow-derived MSCs were obtained from 10 DM patients (5 type 1 DM and 5 type 2 DM) and induced to IPCs under a three-stage protocol. Representative cell surface antigen expression profiles of MSCs were analysed by flow cytometric analysis. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect multiple genes related to pancreatic β-cell development and function. The identity of the IPCs was illustrated by the analysis of morphology, ditizone staining and immunocytochemistry. Release of insulin by these cells was confirmed by immunoradioassay.Results Flow cytometric analysis of MSCs at passage 3 showed that these cells expressed high levels of CD29 (98.28%), CD44 (99.56%) and CD106 (98.34%). Typical islet-like cell clusters were observed at the end of the protocol (18 days). Ditizone staining and immunohistochemistry for insulin were both positive. These differentiated cells at stage 2 (10 days) expressed nestin, pancreatic duodenal homeobox-1 (PDX-1), Neurogenin3, Pax4, insulin, glucagon, but at stage 3 (18 days) we observed the high expression of PDX-1, insulin, glucagon. Insulin was secreted by these cells in response to different concentrations of glucose stimulation in a regulated manner (P<0.05).Conclusions Bone marrow-derived MSCs from DM patients can differentiate into functional IPCs under certain conditions in vitro. Using diabetic patient's own bone marrow-derived MSCs as

  9. Leaf-cutting ant fungi produce cell wall degrading pectinase complexes reminiscent of phytopathogenic fungi

    Directory of Open Access Journals (Sweden)

    Boomsma Jacobus J

    2010-12-01

    Full Text Available Abstract Background Leaf-cutting (attine ants use their own fecal material to manure fungus gardens, which consist of leaf material overgrown by hyphal threads of the basidiomycete fungus Leucocoprinus gongylophorus that lives in symbiosis with the ants. Previous studies have suggested that the fecal droplets contain proteins that are produced by the fungal symbiont to pass unharmed through the digestive system of the ants, so they can enhance new fungus garden growth. Results We tested this hypothesis by using proteomics methods to determine the gene sequences of fecal proteins in Acromyrmex echinatior leaf-cutting ants. Seven (21% of the 33 identified proteins were pectinolytic enzymes that originated from the fungal symbiont and which were still active in the fecal droplets produced by the ants. We show that these enzymes are found in the fecal material only when the ants had access to fungus garden food, and we used quantitative polymerase chain reaction analysis to show that the expression of six of these enzyme genes was substantially upregulated in the fungal gongylidia. These unique structures serve as food for the ants and are produced only by the evolutionarily advanced garden symbionts of higher attine ants, but not by the fungi reared by the basal lineages of this ant clade. Conclusions Pectinolytic enzymes produced in the gongylidia of the fungal symbiont are ingested but not digested by Acromyrmex leaf-cutting ants so that they end up in the fecal fluid and become mixed with new garden substrate. Substantial quantities of pectinolytic enzymes are typically found in pathogenic fungi that attack live plant tissue, where they are known to breach the cell walls to allow the fungal mycelium access to the cell contents. As the leaf-cutting ant symbionts are derived from fungal clades that decompose dead plant material, our results suggest that their pectinolytic enzymes represent secondarily evolved adaptations that are convergent to

  10. Mitochondrial structure in steroid-producing cells: three-dimensional reconstruction of human Leydig cell mitochondria by electron microscopic tomography.

    Science.gov (United States)

    Prince, Frederick P; Buttle, Karolyn F

    2004-05-01

    Mitochondria of human Leydig cells were reconstructed in three dimension utilizing the technique of electron microscopic tomography to obtain a better understanding of the topology of the internal membrane system and the relationship of these cristae to the inner boundary membrane (IBM). Cristae structure, in many respects, is consistent with previous tomographic studies from typical mitochondria, i.e., mitochondria from nonsteroid-producing cells. Cristae are diverse in form, with well-defined lamellar cristae interconnected to pleomorphic and tubular regions. Occasional fenestrations are present in the lamellar regions. Also consistent with other mitochondria studied by tomography, the openings of the cristae to the IBM (referred to as crista junctions) are roughly circular or elliptical and approximately 20-25 nm in diameter. Morphological contact sites between the outer mitochondrial membrane and IBM are also present. Cristae membranes in these steroid-producing mitochondria are often found in close proximity to the IBM. Unique to steroid-producing mitochondria is a form of the cristae in which multiple lamellae are in very close apposition, previously defined as the lamellar association. Tomographic reconstructions of the lamellar association reveal that these well-organized membranes also open to the IBM via crista junctions. These regions of closely apposed lamellar cristae are also interconnected and display small tubular extensions from the lamellae. The current study is the first electron microscopic tomography study of mitochondria from steroid-producing cells. The results show the cristae interconnect to form an extensive internal membrane system, which is perhaps better termed the cristae compartment. This internal membrane system is notable due to the high surface area with few small openings to the IBM. Such a morphology is more analogous to the thylakoid membrane system of chloroplasts than the long-standing view of mitochondrial cristae. The

  11. Plateletpheresis concentrates produced with the COMTEC cell separator: the French experience.

    Science.gov (United States)

    Coffe, C; Benguella, M; Domy, M; Cottier, D; Guignier, F; N'gondara, J P; Carrère, A; Masse, M; Naegelen, C; Biggio, B; Tiberghien, P; Hervè, P; Bouzgarrou, R; Maurel, J P; Vezon, G; Vidal, M; Quainon, F; Benamara, A; Lamy, B; Beaumont, J L; Bierling, P; Gondrexon, G; Schooneman, F; Janot, C; Villard, F; Huart, J J

    2001-08-01

    The latest generation of cell separators such as Trima (Gambro), Amicus (Baxter) and AS-TEC 204 (Fresenius), allow the collection of leucocyte-reduced platelet concentrates without secondary filtration. Fresenius has recently developed the COMTEC cell separator whose performance has been evaluated by several teams in France. This new cell separator is an improved version of the Fresenius AS-TEC 204 cell separator, designed to allow more efficient platelet collections. This study reports on the experience of six French teams (from Bordeaux, Clermont-Ferrand, Creteil, Dijon, Lille and Nancy) who obtained 696 leucocyte-reduced plateletpheresis concentrates in the course of collection using the new Fresenius COMTEC cell separator. All healthy volunteer donors fulfilled French selection criteria for platelet apheresis. Donors were eligible if they had suitable venous accesses, if their bodyweight was *50 kg and if their pre-apheresis platelet count was >150 x 10(9) l(-1). Between 4606 and 5229 ml of blood were processed. The mean volume of the platelet concentrates was between 439 and 493 ml (mean 460 +/- 63 ml). The platelet yield was of the order of 5.18 +/- 1.02 x 10(11) with only one platelet concentrate below the norm of 2 x 10(11) platelets (0.91 x 10(11)). No plausible explanation for this was found. The residual leucocyte levels conform to current norms. The platelet concentrates contained less than 1 x 10(6) leucocytes per concentrate (mean 0.233 +/- 0.150 x 10(6) leucocytes) in more than 97% of the components produced with >95% statistical confidence. The efficacy of the cell separator (52.44 +/- 7.35%) is comparable to that of other separators. The Fresenius COMTEC cell separator makes it possible to obtain leucocyte-reduced platelet concentrates which comply with current standards both in terms of platelet content and residual leucocyte level.

  12. 3 dimensional cell cultures: a comparison between manually and automatically produced alginate beads.

    Science.gov (United States)

    Lehmann, R; Gallert, C; Roddelkopf, T; Junginger, S; Wree, A; Thurow, K

    2016-08-01

    Cancer diseases are a common problem of the population caused by age and increased harmful environmental influences. Herein, new therapeutic strategies and compound screenings are necessary. The regular 2D cultivation has to be replaced by three dimensional cell culturing (3D) for better simulation of in vivo conditions. The 3D cultivation with alginate matrix is an appropriate method for encapsulate cells to form cancer constructs. The automated manufacturing of alginate beads might be an ultimate method for large-scaled manufacturing constructs similar to cancer tissue. The aim of this study was the integration of full automated systems for the production, cultivation and screening of 3D cell cultures. We compared the automated methods with the regular manual processes. Furthermore, we investigated the influence of antibiotics on these 3D cell culture systems. The alginate beads were formed by automated and manual procedures. The automated steps were processes by the Biomek(®) Cell Workstation (celisca, Rostock, Germany). The proliferation and toxicity were manually and automatically evaluated at day 14 and 35 of cultivation. The results visualized an accumulation and expansion of cell aggregates over the period of incubation. However, the proliferation and toxicity were faintly and partly significantly decreased on day 35 compared to day 14. The comparison of the manual and automated methods displayed similar results. We conclude that the manual production process could be replaced by the automation. Using automation, 3D cell cultures can be produced in industrial scale and improve the drug development and screening to treat serious illnesses like cancer.

  13. Metabolic analysis of antibody producing Chinese hamster ovary cell culture under different stresses conditions.

    Science.gov (United States)

    Badsha, Md Bahadur; Kurata, Hiroyuki; Onitsuka, Masayoshi; Oga, Takushi; Omasa, Takeshi

    2016-07-01

    Chinese hamster ovary (CHO) cells are commonly used as the host cell lines concerning their ability to produce therapeutic proteins with complex post-translational modifications. In this study, we have investigated the time course extra- and intracellular metabolome data of the CHO-K1 cell line, under a control and stress conditions. The addition of NaCl and trehalose greatly suppressed cell growth, where the maximum viable cell density of NaCl and trehalose cultures were 2.2-fold and 2.8-fold less than that of a control culture. Contrariwise, the antibody production of both the NaCl and trehalose cultures was sustained for a longer time to surpass that of the control culture. The NaCl and trehalose cultures showed relatively similar dynamics of cell growth, antibody production, and substrate/product concentrations, while they indicated different dynamics from the control culture. The principal component analysis of extra- and intracellular metabolome dynamics indicated that their dynamic behaviors were consistent with biological functions. The qualitative pattern matching classification and hierarchical clustering analyses for the intracellular metabolome identified the metabolite clusters whose dynamic behaviors depend on NaCl and trehalose. The volcano plot revealed several reporter metabolites whose dynamics greatly change between in the NaCl and trehalose cultures. The elastic net identified some critical, intracellular metabolites that are distinct between the NaCl and trehalose. While a relatively small number of intracellular metabolites related to the cell growth, glucose, glutamine, lactate and ammonium ion concentrations, the mechanism of antibody production was suggested to be very complicated or not to be explained by elastic net regression analysis. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  14. A novel method for producing target cells and assessing cytotoxic T lymphocyte activity in outbred hosts

    Directory of Open Access Journals (Sweden)

    Bendinelli Mauro

    2009-03-01

    Full Text Available Abstract Background Cytotoxic T lymphocytes play a crucial role in the immunological control of microbial infections and in the design of vaccines and immunotherapies. Measurement of cytotoxic T lymphocyte activity requires that the test antigen is presented by target cells having the same or compatible class I major hystocompatibility complex antigens as the effector cells. Conventional assays use target cells labeled with 51chromium and infer cytotoxic T lymphocyte activity by measuring the isotope released by the target cells lysed following incubation with antigen-specific cytotoxic T lymphocytes. This assay is sensitive but needs manipulation and disposal of hazardous radioactive reagents and provides a bulk estimate of the reporter released, which may be influenced by spontaneous release of the label and other poorly controllable variables. Here we describe a novel method for producing target in outbred hosts and assessing cytotoxic T lymphocyte activity by flow cytometry. Results The method consists of culturing skin fibroblasts, immortalizing them with a replication defective clone of simian virus 40, and finally transducing them with a bicistronic vector encoding the target antigen and the reporter green fluorescent protein. When used in a flow cytometry-based assay, the target cells obtained with this method proved valuable for assessing the viral envelope protein specific cytotoxic T lymphocyte activity in domestic cats acutely or chronically infected with feline immunodeficiency virus, a lentivirus similar to human immunodeficiency virus and used as animal model for AIDS studies. Conclusion Given the versatility of the bicistronic vector used, its ability to deliver multiple and large transgenes in target cells, and its extremely wide cell specificity when pseudotyped with the vesicular stomatitis virus envelope protein, the method is potentially exploitable in many animal species.

  15. Modeling the hydrodynamics of Phloem sieve plates

    DEFF Research Database (Denmark)

    Jensen, Kaare Hartvig; Mullendore, Daniel Leroy; Holbrook, Noel Michele;

    2012-01-01

    Sieve plates have an enormous impact on the efficiency of the phloem vascular system of plants, responsible for the distribution of photosynthetic products. These thin plates, which separate neighboring phloem cells, are perforated by a large number of tiny sieve pores and are believed to play...... are investigated. We find that the sieve plate resistance is correlated to the cell lumen resistance, and that the sieve plate and the lumen contribute almost equally to the total hydraulic resistance of the phloem translocation pathway....

  16. Efficient enrichment of high-producing recombinant Chinese hamster ovary cells for monoclonal antibody by flow cytometry.

    Science.gov (United States)

    Okumura, Takeshi; Masuda, Kenji; Watanabe, Kazuhiko; Miyadai, Kenji; Nonaka, Koichi; Yabuta, Masayuki; Omasa, Takeshi

    2015-09-01

    To screen a high-producing recombinant Chinese hamster ovary (CHO) cell from transfected cells is generally laborious and time-consuming. We developed an efficient enrichment strategy for high-producing cell screening using flow cytometry (FCM). A stable pool that had possibly shown a huge variety of monoclonal antibody (mAb) expression levels was prepared by transfection of an expression vector for mAb production to a CHO cell. To enrich high-producing cells derived from a stable pool stained with a fluorescent-labeled antibody that binds to mAb presented on the cell surface, we set the cell size and intracellular density gates based on forward scatter (FSC) and side scatter (SSC), and collected the brightest 5% of fluorescein isothiocyanate (FITC)-positive cells from each group by FCM. The final product concentration in a fed-batch culture of cells sorted without FSC and SSC gates was 1.2-1.3-times higher than that of unsorted cells, whereas that of cells gated by FSC and SSC was 3.4-4.7-fold higher than unsorted cells. Surprisingly, the fraction with the highest final product concentration indicated the smallest value of FSC and SSC, and the middle value of fluorescence intensity among all fractionated cells. Our results showed that our new screening strategy by FCM based on FSC and SSC gates could achieve an efficient enrichment of high-producing cells with the smallest value of FSC and SSC.

  17. Molecular characterization of viruses from clinical respiratory samples producing unidentified cytopathic effects in cell culture.

    Science.gov (United States)

    Abed, Yacine; Boivin, Guy

    2009-09-01

    The sequence-independent single primer amplification (SISPA) method was performed to identify a virus in 17 clinical respiratory samples producing uncharacterized cytopathic effects in LLC-MK2 cells. Sequence analysis of 600-1600 bp amplicons allowed the identification of six viruses (one influenza C, two parechovirus-3 and three cardioviruses). Genomic sequences of the cardioviruses showed similarities with those of the recently-described Saffold virus strain although significant variation was present in the viral surface EF and CD loops. These results demonstrate the usefulness of SISPA for identifying emerging viruses and also known viruses not easily identified by standard virological methods.

  18. Molecular Characterization of Viruses from Clinical Respiratory Samples Producing Unidentified Cytopathic Effects in Cell Culture

    Directory of Open Access Journals (Sweden)

    Guy Boivin

    2009-07-01

    Full Text Available The sequence-independent single primer amplification (SISPA method was performed to identify a virus in 17 clinical respiratory samples producing uncharacterized cytopathic effects in LLC-MK2 cells. Sequence analysis of 600-1600 bp amplicons allowed the identification of six viruses (one influenza C, two parechovirus-3 and three cardioviruses. Genomic sequences of the cardioviruses showed similarities with those of the recently-described Saffold virus strain although significant variation was present in the viral surface EF and CD loops. These results demonstrate the usefulness of SISPA for identifying emerging viruses and also known viruses not easily identified by standard virological methods.

  19. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    Science.gov (United States)

    Howard, Stanley R.; Korinko, Paul S.

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated