Science.gov

Sample records for cell generator development

  1. Research and development of fuel cell generation technology

    NASA Astrophysics Data System (ADS)

    1985-04-01

    Low-temperature, low-pressure phosporic-acid fuel-cell power generation systems are being developed, as are matrix and paste electrolyte type molten-carbonate fuel-cell pilots plants. System analyses are also reported.

  2. Development of the fuel cell power generation technology, 2

    NASA Astrophysics Data System (ADS)

    1994-02-01

    NEDO arranged results of the research on the development of the fuel cell power generation technology during fiscal 1981 to 1987. During 1981 to 1983, research and development were made on a dispersed generation type fuel cell power generation system using phosphoric acid fuel cells (low temperature/pressure type) and a thermal power plant substitution type fuel cell power generation system (high temperature/pressure type). During 1984 to 1986, in addition to the above, research was made on a total system of phosphoric acid fuel cells, trial operation of a molten carbonate fuel cell power plant (matrix electrolyte method, paste electrolyte method) and a total system. In 1987, as to molten carbonate fuel cells, researches were made on stacks and a peripheral system, support, and a total system. As a comprehensive technology development of phosphoric acid fuel cells, researches were made on a fuel cell power generation system for isolated island use and a fuel cell power generation system for business use.

  3. Oligodendrocyte precursor cells generate pituicytes in vivo during neurohypophysis development.

    PubMed

    Virard, Isabelle; Coquillat, Delphine; Bancila, Mircea; Kaing, Sovann; Durbec, Pascale

    2006-02-01

    In the vertebrate brain, much remains to be understood concerning the origin of glial cell diversity and the potential lineage relationships between the various types of glia. Besides astrocytes and myelin-forming oligodendrocytes, other macroglial cell populations are found in discrete areas of the central nervous system (CNS). They share functional features with astrocytes and oligodendrocytes but also display specific characteristics. Such specialized cells, called pituicytes, are located in the neurohypophysis (NH). Our work focuses on the lineage of the pituicytes during rodent development. First, we show that cells identified with a combination of oligodendrocyte precursor cell (OPC) markers are present in the developing rat NH. In culture, neonatal NH progenitors also share major functional characteristics with OPCs, being both migratory and bipotential, i.e. able to give rise to type 2 astrocytes and oligodendrocytes. We then observe that, either in vitro or after transplantation into myelin-deficient Shiverer brain, pieces of NH generate myelinating oligodendrocytes, confirming the oligodendrogenic potentiality of NH cells. However, no mature oligodendrocyte can be found in the NH. This led us to hypothesize that the OPCs present in the developing NH might be generating other glial cells, especially the pituicytes. Consistent with this hypothesis, the OPCs appear during NH development before pituicytes differentiate. Finally, we establish a lineage relationship between olig1+ cells, most likely OPCs, and the pituicytes by fate-mapping experiments using genetically engineered mice. This constitutes the first demonstration that OPCs generate glial cells other than oligodendrocytes in vivo.

  4. Development of first generation aerospace NiMH cells

    NASA Technical Reports Server (NTRS)

    Tinker, Lawrence; Dell, Dan; Wu, Tony; Rampel, Guy

    1993-01-01

    Gates Aerospace Batteries in conjunction with Gates Energy Products (GEP) has been developing NiMH technology for aerospace use since 1990. GEP undertook the development of NiMH technology for commercial cell applications in 1987. This program focused on wound cell technology for replacement of current NiCd technology. As an off shoot of this program small, wound cells were used to evaluate initial design options for aerospace prismatic cell designs. Early in 1991, the first aerospace prismatic cell designs were built in a 6 Ah cell configuration. These cells were used to initially characterize performance in prismatic configurations and begin early life cycle testing. Soon after the 6 Ah cells were on test, several 22 Ah cells were built to test other options. The results of testing of these cells were used to identify potential problem areas for long lived cells and develop solutions to those problems. Following these two cell builds, a set of 7 Ah cells was built to evaluate improvements to the technology. To date results from these tests are very promising. Cycle lives in excess of 2,200 LEO cycles at 50 percent DoD were achieved with cells continuing on test. Results from these cell tests are discussed and data presented to demonstrate feasibility of this technology for aerospace programs.

  5. High Temperature Solid Oxide Fuel Cell Generator Development

    SciTech Connect

    Joseph Pierre

    2007-09-30

    This report describes the results of the tubular SOFC development program from August 22, 1997 to September 30, 2007 under the Siemens/U.S. Department of Energy Cooperative Agreement. The technical areas discussed include cell manufacturing development, cell power enhancement, SOFC module and system cost reduction and technology advancement, and our field unit test program. Whereas significant progress has been made toward commercialization, significant effort remains to achieve our cost, performance and reliability targets for successful commercialization.

  6. High Temperature Solid Oxide Fuel Cell Generator Development

    SciTech Connect

    Joseph F. Pierre

    2006-08-21

    Work performed during the period February 21, 2006 through August 21, 2006 is summarized herein. During this period, efforts were focused on 5 kWe bundle testing, development of on-cell reformation, the conceptual design of an advanced module, and the development of a manufacturing roadmap for cells and bundles. A 5 kWe SOFC system was built and delivered to the Pennsylvania State University; fabrication of a second 5 kWe SOFC for delivery to Montana State University was initiated. Cell testing and microstructural analysis in support of these efforts was also conducted.

  7. Development of the Generative Cell Wall in Monotropa uniflora L. Pollen.

    PubMed

    Lutz, R W; Sjolund, R D

    1973-11-01

    During an ultrastructural survey of an achlorophyllus dicotyledonous plant, Monotropa uniflora L., a stage of pollen development was encountered which suggests a relationship between the activity of the rough endoplasmic reticulum and the development of the generative cell wall.

  8. HIGH-TEMPERATURE TUBULAR SOLID OXIDE FUEL CELL GENERATOR DEVELOPMENT

    SciTech Connect

    S.E. Veyo

    1998-09-01

    During the Westinghouse/USDOE Cooperative Agreement period of November 1, 1990 through November 30, 1997, the Westinghouse solid oxide fuel cell has evolved from a 16 mm diameter, 50 cm length cell with a peak power of 1.27 watts/cm to the 22 mm diameter, 150 cm length dimensions of today's commercial prototype cell with a peak power of 1.40 watts/cm. Accompanying the increase in size and power density was the elimination of an expensive EVD step in the manufacturing process. Demonstrated performance of Westinghouse's tubular SOFC includes a lifetime cell test which ran for a period in excess of 69,000 hours, and a fully integrated 25 kWe-class system field test which operated for over 13,000 hours at 90% availability with less than 2% performance degradation over the entire period. Concluding the agreement period, a 100 kW SOFC system successfully passed its factory acceptance test in October 1997 and was delivered in November to its demonstration site in Westervoort, The Netherlands.

  9. Development of the Generative Cell Wall in Monotropa uniflora L. Pollen

    PubMed Central

    Lutz, Richard W.; Sjolund, Richard D.

    1973-01-01

    During an ultrastructural survey of an achlorophyllus dicotyledonous plant, Monotropa uniflora L., a stage of pollen development was encountered which suggests a relationship between the activity of the rough endoplasmic reticulum and the development of the generative cell wall. Images PMID:16658591

  10. Generation of recombinant arenavirus for vaccine development in FDA-approved Vero cells.

    PubMed

    Cheng, Benson Y H; Ortiz-Riaño, Emilio; de la Torre, Juan Carlos; Martínez-Sobrido, Luis

    2013-08-01

    The development and implementation of arenavirus reverse genetics represents a significant breakthrough in the arenavirus field. The use of cell-based arenavirus minigenome systems together with the ability to generate recombinant infectious arenaviruses with predetermined mutations in their genomes has facilitated the investigation of the contribution of viral determinants to the different steps of the arenavirus life cycle, as well as virus-host interactions and mechanisms of arenavirus pathogenesis. In addition, the development of trisegmented arenaviruses has permitted the use of the arenavirus genome to express additional foreign genes of interest, thus opening the possibility of arenavirus-based vaccine vector applications. Likewise, the development of single-cycle infectious arenaviruses capable of expressing reporter genes provides a new experimental tool to improve the safety of research involving highly pathogenic human arenaviruses. The generation of recombinant arenaviruses using plasmid-based reverse genetics techniques has so far relied on the use of rodent cell lines, which poses some barriers for the development of Food and Drug Administration (FDA)-licensed vaccine or vaccine vectors. To overcome this obstacle, we describe here the efficient generation of recombinant arenaviruses in FDA-approved Vero cells.

  11. Development of planar solid oxide fuel cells for power generation applications

    SciTech Connect

    Minh, N.Q.

    1996-04-01

    Planar solid oxide fuel cells (SOFCs) are presently being developed for a variety of electric power generation application. The planar design offers simple cell geometry, high power density, and multiple fabrication and gas manifolding options. Planar SOFC technology has received much attention recently, and significant progress has been made in this area. Recent effort at AlliedSignal has focused on the development of high-performance, lightweight planar SOFCs, having thin-electrolyte films, that can be operated efficiently at reduced temperatures (< 1000{degrees}C). The advantages of reduced-temperature operation include wider material choice (including use of metallic interconnects), expected longer cell life, reduced thermal stress, improved reliability, and reduced fuel cell cost. The key aspect in the development of thin-film SIFCs is to incorporate the thin electrolyte layer into the desired structure of cells in a manner that yields the required characteristics. AlliedSignal has developed a simple and cost-effective method based on tape calendering for the fabrication of thin-electrolyte SOFCs. Thin-electrolyte cells made by tape calendering have shown extraordinary performance, e.g., producing more than 500mW/cm{sup 2} at 700{degrees}C and 800mW/cm{sup 2} at 800{degrees}C with hydrogen as fuel and air is oxidant. thin-electrolyte single cells have been incorporated into a compliant metallic stack structure and operated at reduced and operated at reduced-temperature conditions.

  12. Generation of Reactive Oxygen Species Contributes to the Development of Carbon Black Cytotoxicity to Vascular Cells

    PubMed Central

    Lee, Jong Gwan; Noh, Won Jun; Kim, Hwa

    2011-01-01

    Carbon black, a particulate form of pure elemental carbon, is an industrial chemical with the high potential of occupational exposure. Although the relationship between exposure to particulate matters (PM) and cardiovascular diseases is well established, the cardiovascular risk of carbon black has not been characterized clearly. In this study, the cytotoxicity of carbon black to vascular smooth muscle and endothelial cells were examined to investigate the potential vascular toxicity of carbon black. Carbon black with distinct particle size, N330 (primary size, 28~36 nm) and N990 (250~350 nm) were treated to A-10, rat aortic smooth muscle cells and human umbilical vein endothelial cell line, ECV304, and cell viability was assessed by lactate dehydrogenase (LDH) leakage assay. Treatment of carbon black N990 resulted in the significant reduction of viability in A-10 cells at 100 μg/ml, the highest concentration tested, while N330 failed to cause cell death. Cytotoxicity to ECV304 cells was induced only by N330 at higher concentration, 200 μg/ml, suggesting that ECV304 cells were relatively resistant to carbon black. Treatment of 100 μg/ml N990 led to the elevation of reactive oxygen species (ROS) detected by dichlorodihydrofluorescein (DCF) in A-10 cells. Pretreatment of antioxidants, N-acetylcysteine (NAC) and sulforaphane restored decreased viability of N990-treated A-10 cells, and N-acetylcysteine, but not sulforaphane, attenuated N990-induced ROS generation in A-10 cells. Taken together, present study shows that carbon black is cytotoxic to vascular cells, and the generation of reactive oxygen contributes to the development of cytotoxicity. ROS scavenging antioxidant could be a potential strategy to attenuate the toxicity induced by carbon black exposure. PMID:24278567

  13. Multipotent neural stem cells generate glial cells of the central complex through transit amplifying intermediate progenitors in Drosophila brain development.

    PubMed

    Viktorin, Gudrun; Riebli, Nadia; Popkova, Anna; Giangrande, Angela; Reichert, Heinrich

    2011-08-15

    The neural stem cells that give rise to the neural lineages of the brain can generate their progeny directly or through transit amplifying intermediate neural progenitor cells (INPs). The INP-producing neural stem cells in Drosophila are called type II neuroblasts, and their neural progeny innervate the central complex, a prominent integrative brain center. Here we use genetic lineage tracing and clonal analysis to show that the INPs of these type II neuroblast lineages give rise to glial cells as well as neurons during postembryonic brain development. Our data indicate that two main types of INP lineages are generated, namely mixed neuronal/glial lineages and neuronal lineages. Genetic loss-of-function and gain-of-function experiments show that the gcm gene is necessary and sufficient for gliogenesis in these lineages. The INP-derived glial cells, like the INP-derived neuronal cells, make major contributions to the central complex. In postembryonic development, these INP-derived glial cells surround the entire developing central complex neuropile, and once the major compartments of the central complex are formed, they also delimit each of these compartments. During this process, the number of these glial cells in the central complex is increased markedly through local proliferation based on glial cell mitosis. Taken together, these findings uncover a novel and complex form of neurogliogenesis in Drosophila involving transit amplifying intermediate progenitors. Moreover, they indicate that type II neuroblasts are remarkably multipotent neural stem cells that can generate both the neuronal and the glial progeny that make major contributions to one and the same complex brain structure.

  14. Imidacloprid Exposure Suppresses Neural Crest Cells Generation during Early Chick Embryo Development.

    PubMed

    Wang, Chao-Jie; Wang, Guang; Wang, Xiao-Yu; Liu, Meng; Chuai, Manli; Lee, Kenneth Ka Ho; He, Xiao-Song; Lu, Da-Xiang; Yang, Xuesong

    2016-06-15

    Imidacloprid is a neonicotinoid pesticide that is widely used in the control pests found on crops and fleas on pets. However, it is still unclear whether imidacloprid exposure could affect early embryo development-despite some studies having been conducted on the gametes. In this study, we demonstrated that imidacloprid exposure could lead to abnormal craniofacial osteogenesis in the developing chick embryo. Cranial neural crest cells (NCCs) are the progenitor cells of the chick cranial skull. We found that the imidacloprid exposure retards the development of gastrulating chick embryos. HNK-1, PAX7, and Ap-2α immunohistological stainings indicated that cranial NCCs generation was inhibited after imidacloprid exposure. Double immunofluorescent staining (Ap-2α and PHIS3 or PAX7 and c-Caspase3) revealed that imidacloprid exposure inhibited both NCC proliferation and apoptosis. In addition, it inhibited NCCs production by repressing Msx1 and BMP4 expression in the developing neural tube and by altering expression of EMT-related adhesion molecules (Cad6B, E-Cadherin, and N-cadherin) in the developing neural crests. We also determined that imidacloprid exposure suppressed cranial NCCs migration and their ability to differentiate. In sum, we have provided experimental evidence that imidacloprid exposure during embryogenesis disrupts NCCs development, which in turn causes defective cranial bone development.

  15. Long-term persistence and development of induced pancreatic beta cells generated by lineage conversion of acinar cells.

    PubMed

    Li, Weida; Cavelti-Weder, Claudia; Zhang, Yingying; Zhang, Yinying; Clement, Kendell; Donovan, Scott; Gonzalez, Gabriel; Zhu, Jiang; Stemann, Marianne; Xu, Ke; Hashimoto, Tatsu; Yamada, Takatsugu; Nakanishi, Mio; Zhang, Yuemei; Zeng, Samuel; Gifford, David; Meissner, Alexander; Weir, Gordon; Zhou, Qiao

    2014-12-01

    Direct lineage conversion is a promising approach to generate therapeutically important cell types for disease modeling and tissue repair. However, the survival and function of lineage-reprogrammed cells in vivo over the long term has not been examined. Here, using an improved method for in vivo conversion of adult mouse pancreatic acinar cells toward beta cells, we show that induced beta cells persist for up to 13 months (the length of the experiment), form pancreatic islet-like structures and support normoglycemia in diabetic mice. Detailed molecular analyses of induced beta cells over 7 months reveal that global DNA methylation changes occur within 10 d, whereas the transcriptional network evolves over 2 months to resemble that of endogenous beta cells and remains stable thereafter. Progressive gain of beta-cell function occurs over 7 months, as measured by glucose-regulated insulin release and suppression of hyperglycemia. These studies demonstrate that lineage-reprogrammed cells persist for >1 year and undergo epigenetic, transcriptional, anatomical and functional development toward a beta-cell phenotype.

  16. Development of a hydrogen generator for fuel cells based on the partial oxidation of methane

    SciTech Connect

    Recupero, V.; Torre, T.; Saija, G.; Fiordano, N.

    1996-12-31

    As well known, the most acknowledged process for generation of hydrogen for fuel cells is based upon the steam reforming of methane or natural gas (SRM). The reaction is endothermic ({Delta}H{sub 298}= 206 kJ/mole) and high H{sub 2}O/CH{sub 4} ratios are required in order to limit coke formation at T higher than 1000 K. Moreover, it is a common practice that the process`s fuel economy is highly sensitive to proper heat fluxes and reactor design (tubular type) and to operational conditions. Efficient heat recovery can be accomplished only on large scale units (> 40,000 Nm{sup 3}/h), far from the range of interest of {open_quotes}on-site{close_quotes} fuel cells. Even if, to fit the needs of the fuel cell technology, medium sized external reforming units (50-200 Nm{sup 3} H{sub 2}/h) have been developed and/or planned for integration with both the first and the second generation fuel cells, amelioration in their heat recovery and efficiency is at the expense of an increased sophistication and therefore at higher per unit costs. In all cases, SRM requires an extra {open_quotes}fuel{close_quotes} supply (to substain the endothermicity of the reaction) in addition to stoichiometric requirements ({open_quotes}feed{close_quotes} gas). A valid alternative could be a process based on catalytic partial oxidation of CH{sub 4} (CSPOM), since the process is mildly exothermic ({Delta}H{sub 298}= -35.6 kJ/mole) and therefore not energy intensive. Consequently, great interest is expected from conversion of methane into syngas, if an autothermal, low energy intensive, compact and reliable process could be developed.

  17. Third generation tyrosine kinase inhibitors and their development in advanced renal cell carcinoma.

    PubMed

    Bukowski, Ronald M

    2012-01-01

    Angiogenesis in general and the vascular endothelial growth factor (VEGF) signaling axis in particular is a validated target in renal cell carcinoma (RCC). Clear-cell carcinoma of the kidney is now recognized as a malignancy that is sensitive to inhibitors of the VEGF pathway. Treatment options for patients with metastatic renal cell carcinoma have evolved in dramatic fashion over the past 6 years, and a new paradigm has developed. The cytokines interferon-α and interleukin-2 were previously utilized for therapy, but since December 2005, six new agents have been approved in the United States for the treatment of advanced RCC. Two are tyrosine kinase inhibitors (TKI's) including sunitinib and recently pazopanib, and the multikinase inhibitor sorafenib. The current review examines the evolving data with the next generation of TKI's, axitinib and tivozanib being developed for the treatment of advanced RCC. These agents were synthesized to provide increased target specificity and enhanced target inhibition. The preclinical and clinical data are examined, an overview of the development of these TKI's is provided, and discussion plus speculation concerning their potential roles as RCC therapy is provided.

  18. Third Generation Tyrosine Kinase Inhibitors and Their Development in Advanced Renal Cell Carcinoma

    PubMed Central

    Bukowski, Ronald M.

    2012-01-01

    Angiogenesis in general and the vascular endothelial growth factor (VEGF) signaling axis in particular is a validated target in renal cell carcinoma (RCC). Clear-cell carcinoma of the kidney is now recognized as a malignancy that is sensitive to inhibitors of the VEGF pathway. Treatment options for patients with metastatic renal cell carcinoma have evolved in dramatic fashion over the past 6 years, and a new paradigm has developed. The cytokines interferon-α and interleukin-2 were previously utilized for therapy, but since December 2005, six new agents have been approved in the United States for the treatment of advanced RCC. Two are tyrosine kinase inhibitors (TKI’s) including sunitinib and recently pazopanib, and the multikinase inhibitor sorafenib. The current review examines the evolving data with the next generation of TKI’s, axitinib and tivozanib being developed for the treatment of advanced RCC. These agents were synthesized to provide increased target specificity and enhanced target inhibition. The preclinical and clinical data are examined, an overview of the development of these TKI’s is provided, and discussion plus speculation concerning their potential roles as RCC therapy is provided. PMID:22655261

  19. In vitro expanded stem cells from the developing retina fail to generate photoreceptors but differentiate into myelinating oligodendrocytes.

    PubMed

    Czekaj, Magdalena; Haas, Jochen; Gebhardt, Marlen; Müller-Reichert, Thomas; Humphries, Peter; Farrar, Jane; Bartsch, Udo; Ader, Marius

    2012-01-01

    Cell transplantation to treat retinal degenerative diseases represents an option for the replacement of lost photoreceptor cells. In vitro expandable cells isolated from the developing mammalian retina have been suggested as a potential source for the generation of high numbers of donor photoreceptors. In this study we used standardized culture conditions based on the presence of the mitogens FGF-2 and EGF to generate high numbers of cells in vitro from the developing mouse retina. These presumptive 'retinal stem cells' ('RSCs') can be propagated as monolayer cultures over multiple passages, express markers of undifferentiated neural cells, and generate neuronal and glial cell types upon withdrawal of mitogens in vitro or following transplantation into the adult mouse retina. The proportion of neuronal differentiation can be significantly increased by stepwise removal of mitogens and inhibition of the notch signaling pathway. However, 'RSCs', by contrast to their primary counterparts in vivo, i.e. retinal progenitor cells, loose the expression of retina-specific progenitor markers like Rax and Chx10 after passaging and fail to differentiate into photoreceptors both in vitro or after intraretinal transplantation. Notably, 'RSCs' can be induced to differentiate into myelinating oligodendrocytes, a cell type not generated by primary retinal progenitor cells. Based on these findings we conclude that 'RSCs' expanded in high concentrations of FGF-2 and EGF loose their retinal identity and acquire features of in vitro expandable neural stem-like cells making them an inappropriate cell source for strategies aimed at replacing photoreceptor cells in the degenerated retina.

  20. Olig2 regulates Purkinje cell generation in the early developing mouse cerebellum

    PubMed Central

    Ju, Jun; Liu, Qian; Zhang, Yang; Liu, Yuanxiu; Jiang, Mei; Zhang, Liguo; He, Xuelian; Peng, Chenchen; Zheng, Tao; Lu, Q. Richard; Li, Hedong

    2016-01-01

    The oligodendrocyte transcription factor Olig2 plays a crucial role in the neurogenesis of both spinal cord and brain. In the cerebellum, deletion of both Olig2 and Olig1 results in impaired genesis of Purkinje cells (PCs) and Pax2+ interneurons. Here, we perform an independent study to show that Olig2 protein is transiently expressed in the cerebellar ventricular zone (VZ) during a period when PCs are specified. Further analyses demonstrate that Olig2 is expressed in both cerebellar VZ progenitors and early-born neurons. In addition, unlike in the ganglionic eminence of the embryonic forebrain where Olig2 is mostly expressed in proliferating progenitors, Olig2+ cells in the cerebellar VZ are in the process of leaving the cell cycle and differentiating into postmitotic neurons. Functionally, deletion of Olig2 alone results in a preferential reduction of PCs in the cerebellum, which is likely mediated by decreased neuronal generation from their cerebellar VZ progenitors. Furthermore, our long-term lineage tracing experiments show that cerebellar Olig gene-expressing progenitors produce PCs but rarely Pax2+ interneurons in the developing cerebellum, which opposes the “temporal identity transition” model of the cerebellar VZ progenitors stating that majority of Pax2+ interneuron progenitors are transitioned from Olig2+ PC progenitors. PMID:27469598

  1. Development of TMI Logistic Fuel Solid Oxide Fuel Cell (SOFC) for Advanced Military Power Generation Systems

    DTIC Science & Technology

    2007-11-02

    Power generation systems based on the Technology Management, Inc. (TMI) solid oxide fuel cell (SOFC) are an optional modality for military...integrated system using TMI’s proprietary sulfur-tolerant planar solid oxide fuel cell (SOFC) and steam reformer, integrated into a compact unit which

  2. Signaling and Transcription Factors during Inner Ear Development: The Generation of Hair Cells and Otic Neurons

    PubMed Central

    Gálvez, Héctor; Abelló, Gina; Giraldez, Fernando

    2017-01-01

    Integration between cell signals and bHLH transcription factors plays a prominent role during the development of hair cells of the inner ear. Hair cells are the sensory receptors of the inner ear, responsible for the mechano-transduction of sound waves into electrical signals. They derive from multipotent progenitors that reside in the otic placode. Progenitor commitment is the result of cell signaling from the surrounding tissues that result in the restricted expression of SoxB1 transcription factors, Sox2 and Sox3. In turn, they induce the expression of Neurog1 and Atoh1, two bHLH factors that specify neuronal and hair cell fates, respectively. Neuronal and hair cell development, however, do not occur simultaneously. Hair cell development is prevented during neurogenesis and prosensory stages, resulting in the delay of hair cell development with respect to neuron production. Negative interactions between Neurog1 and Atoh1, and of Atoh1 with other bHLH factors driven by Notch signaling, like Hey1 and Hes5, account for this delay. In summary, the regulation of Atoh1 and hair cell development relies on interactions between cell signaling and bHLH transcription factors that dictate cell fate and timing decisions during development. Interestingly, these mechanisms operate as well during hair cell regeneration after damage and during stem cell directed differentiation, making developmental studies instrumental for improving therapies for hearing impairment. PMID:28393066

  3. Analgesic exposure in pregnant rats affects fetal germ cell development with inter-generational reproductive consequences

    PubMed Central

    Dean, Afshan; van den Driesche, Sander; Wang, Yili; McKinnell, Chris; Macpherson, Sheila; Eddie, Sharon L.; Kinnell, Hazel; Hurtado-Gonzalez, Pablo; Chambers, Tom J.; Stevenson, Kerrie; Wolfinger, Elke; Hrabalkova, Lenka; Calarrao, Ana; Bayne, Rosey AL; Hagen, Casper P.; Mitchell, Rod T.; Anderson, Richard A.; Sharpe, Richard M.

    2016-01-01

    Analgesics which affect prostaglandin (PG) pathways are used by most pregnant women. As germ cells (GC) undergo developmental and epigenetic changes in fetal life and are PG targets, we investigated if exposure of pregnant rats to analgesics (indomethacin or acetaminophen) affected GC development and reproductive function in resulting offspring (F1) or in the F2 generation. Exposure to either analgesic reduced F1 fetal GC number in both sexes and altered the tempo of fetal GC development sex-dependently, with delayed meiotic entry in oogonia but accelerated GC differentiation in males. These effects persisted in adult F1 females as reduced ovarian and litter size, whereas F1 males recovered normal GC numbers and fertility by adulthood. F2 offspring deriving from an analgesic-exposed F1 parent also exhibited sex-specific changes. F2 males exhibited normal reproductive development whereas F2 females had smaller ovaries and reduced follicle numbers during puberty/adulthood; as similar changes were found for F2 offspring of analgesic-exposed F1 fathers or mothers, we interpret this as potentially indicating an analgesic-induced change to GC in F1. Assuming our results are translatable to humans, they raise concerns that analgesic use in pregnancy could potentially affect fertility of resulting daughters and grand-daughters. PMID:26813099

  4. Effects of spaced learning in the water maze on development of dentate granule cells generated in adult mice.

    PubMed

    Trinchero, Mariela F; Koehl, Muriel; Bechakra, Malik; Delage, Pauline; Charrier, Vanessa; Grosjean, Noelle; Ladeveze, Elodie; Schinder, Alejandro F; Abrous, D Nora

    2015-11-01

    New dentate granule cells (GCs) are generated in the hippocampus throughout life. These adult-born neurons are required for spatial learning in the Morris water maze (MWM). In rats, spatial learning shapes the network by regulating their number and dendritic development. Here, we explored whether such modulatory effects exist in mice. New GCs were tagged using thymidine analogs or a GFP-expressing retrovirus. Animals were exposed to a reference memory protocol for 10-14 days (spaced training) at different times after newborn cells labeling. Cell proliferation, cell survival, cell death, neuronal phenotype, and dendritic and spine development were examined using immunohistochemistry. Surprisingly, spatial learning did not modify any of the parameters under scrutiny including cell number and dendritic morphology. These results suggest that although new GCs are required in mice for spatial learning in the MWM, they are, at least for the developmental intervals analyzed here, refractory to behavioral stimuli generated in the course of learning in the MWM.

  5. Delayed dendritic development in newly generated dentate granule cells by cell-autonomous expression of the amyloid precursor protein.

    PubMed

    Morgenstern, Nicolás A; Giacomini, Damiana; Lombardi, Gabriela; Castaño, Eduardo M; Schinder, Alejandro F

    2013-09-01

    Neuronal connectivity and synaptic remodeling are fundamental substrates for higher brain functions. Understanding their dynamics in the mammalian allocortex emerges as a critical step to tackle the cellular basis of cognitive decline that occurs during normal aging and in neurodegenerative disorders. In this work we have designed a novel approach to assess alterations in the dynamics of functional and structural connectivity elicited by chronic cell-autonomous overexpression of the human amyloid precursor protein (hAPP). We have taken advantage of the fact that the hippocampus continuously generates new dentate granule cells (GCs) to probe morphofunctional development of GCs expressing different variants of hAPP in a healthy background. hAPP was expressed together with a fluorescent reporter in neural progenitor cells of the dentate gyrus of juvenile mice by retroviral delivery. Neuronal progeny was analyzed several days post infection (dpi). Amyloidogenic cleavage products of hAPP such as the β-C terminal fragment (β-CTF) induced a substantial reduction in glutamatergic connectivity at 21 dpi, at which time new GCs undergo active growth and synaptogenesis. Interestingly, this effect was transient, since the strength of glutamatergic inputs was normal by 35 dpi. This delay in glutamatergic synaptogenesis was paralleled by a decrease in dendritic length with no changes in spine density, consistent with a protracted dendritic development without alterations in synapse formation. Finally, similar defects in newborn GC development were observed by overexpression of α-CTF, a non-amyloidogenic cleavage product of hAPP. These results indicate that hAPP can elicit protracted dendritic development independently of the amyloidogenic processing pathway. © 2013.

  6. Fuel cell generator

    DOEpatents

    Makiel, Joseph M.

    1985-01-01

    A high temperature solid electrolyte fuel cell generator comprising a housing means defining a plurality of chambers including a generator chamber and a combustion products chamber, a porous barrier separating the generator and combustion product chambers, a plurality of elongated annular fuel cells each having a closed end and an open end with the open ends disposed within the combustion product chamber, the cells extending from the open end through the porous barrier and into the generator chamber, a conduit for each cell, each conduit extending into a portion of each cell disposed within the generator chamber, each conduit having means for discharging a first gaseous reactant within each fuel cell, exhaust means for exhausting the combustion product chamber, manifolding means for supplying the first gaseous reactant to the conduits with the manifolding means disposed within the combustion product chamber between the porous barrier and the exhaust means and the manifolding means further comprising support and bypass means for providing support of the manifolding means within the housing while allowing combustion products from the first and a second gaseous reactant to flow past the manifolding means to the exhaust means, and means for flowing the second gaseous reactant into the generator chamber.

  7. Fuel cell generator

    DOEpatents

    Isenberg, Arnold O.

    1983-01-01

    High temperature solid oxide electrolyte fuel cell generators which allow controlled leakage among plural chambers in a sealed housing. Depleted oxidant and fuel are directly reacted in one chamber to combust remaining fuel and preheat incoming reactants. The cells are preferably electrically arranged in a series-parallel configuration.

  8. Evolutionary process development towards next generation crystalline silicon solar cells : a semiconductor process toolbox application

    NASA Astrophysics Data System (ADS)

    John, J.; Prajapati, V.; Vermang, B.; Lorenz, A.; Allebe, C.; Rothschild, A.; Tous, L.; Uruena, A.; Baert, K.; Poortmans, J.

    2012-08-01

    Bulk crystalline Silicon solar cells are covering more than 85% of the world's roof top module installation in 2010. With a growth rate of over 30% in the last 10 years this technology remains the working horse of solar cell industry. The full Aluminum back-side field (Al BSF) technology has been developed in the 90's and provides a production learning curve on module price of constant 20% in average. The main reason for the decrease of module prices with increasing production capacity is due to the effect of up scaling industrial production. For further decreasing of the price per wattpeak silicon consumption has to be reduced and efficiency has to be improved. In this paper we describe a successive efficiency improving process development starting from the existing full Al BSF cell concept. We propose an evolutionary development includes all parts of the solar cell process: optical enhancement (texturing, polishing, anti-reflection coating), junction formation and contacting. Novel processes are benchmarked on industrial like baseline flows using high-efficiency cell concepts like i-PERC (Passivated Emitter and Rear Cell). While the full Al BSF crystalline silicon solar cell technology provides efficiencies of up to 18% (on cz-Si) in production, we are achieving up to 19.4% conversion efficiency for industrial fabricated, large area solar cells with copper based front side metallization and local Al BSF applying the semiconductor toolbox.

  9. Development of a shear stress-free microfluidic gradient generator capable of quantitatively analyzing single-cell morphology.

    PubMed

    Barata, David; Spennati, Giulia; Correia, Cristina; Ribeiro, Nelson; Harink, Björn; van Blitterswijk, Clemens; Habibovic, Pamela; van Rijt, Sabine

    2017-09-07

    Microfluidics, the science of engineering fluid streams at the micrometer scale, offers unique tools for creating and controlling gradients of soluble compounds. Gradient generation can be used to recreate complex physiological microenvironments, but is also useful for screening purposes. For example, in a single experiment, adherent cells can be exposed to a range of concentrations of the compound of interest, enabling high-content analysis of cell behaviour and enhancing throughput. In this study, we present the development of a microfluidic screening platform where, by means of diffusion, gradients of soluble compounds can be generated and sustained. This platform enables the culture of adherent cells under shear stress-free conditions, and their exposure to a soluble compound in a concentration gradient-wise manner. The platform consists of five serial cell culture chambers, all coupled to two lateral fluid supply channels that are used for gradient generation through a source-sink mechanism. Furthermore, an additional inlet and outlet are used for cell seeding inside the chambers. Finite element modeling was used for the optimization of the design of the platform and for validation of the dynamics of gradient generation. Then, as a proof-of-concept, human osteosarcoma MG-63 cells were cultured inside the platform and exposed to a gradient of Cytochalasin D, an actin polymerization inhibitor. This set-up allowed us to analyze cell morphological changes over time, including cell area and eccentricity measurements, as a function of Cytochalasin D concentration by using fluorescence image-based cytometry.

  10. Process Developed for Generating Ceramic Interconnects With Low Sintering Temperatures for Solid Oxide Fuel Cells

    NASA Technical Reports Server (NTRS)

    Zhong, Zhi-Min; Goldsby, Jon C.

    2005-01-01

    Solid oxide fuel cells (SOFCs) have been considered as premium future power generation devices because they have demonstrated high energy-conversion efficiency, high power density, and extremely low pollution, and have the flexibility of using hydrocarbon fuel. The Solid-State Energy Conversion Alliance (SECA) initiative, supported by the U.S. Department of Energy and private industries, is leading the development and commercialization of SOFCs for low-cost stationary and automotive markets. The targeted power density for the initiative is rather low, so that the SECA SOFC can be operated at a relatively low temperature (approx. 700 C) and inexpensive metallic interconnects can be utilized in the SOFC stack. As only NASA can, the agency is investigating SOFCs for aerospace applications. Considerable high power density is required for the applications. As a result, the NASA SOFC will be operated at a high temperature (approx. 900 C) and ceramic interconnects will be employed. Lanthanum chromite-based materials have emerged as a leading candidate for the ceramic interconnects. The interconnects are expected to co-sinter with zirconia electrolyte to mitigate the interface electric resistance and to simplify the processing procedure. Lanthanum chromites made by the traditional method are sintered at 1500 C or above. They react with zirconia electrolytes (which typically sinter between 1300 and 1400 C) at the sintering temperature of lanthanum chromites. It has been envisioned that lanthanum chromites with lower sintering temperatures can be co-fired with zirconia electrolyte. Nonstoichiometric lanthanum chromites can be sintered at lower temperatures, but they are unstable and react with zirconia electrolyte during co-sintering. NASA Glenn Research Center s Ceramics Branch investigated a glycine nitrate process to generate fine powder of the lanthanum-chromite-based materials. By simultaneously doping calcium on the lanthanum site, and cobalt and aluminum on the

  11. FGF/FGFR2 signaling regulates the generation and correct positioning of Bergmann glia cells in the developing mouse cerebellum.

    PubMed

    Meier, Florian; Giesert, Florian; Delic, Sabit; Faus-Kessler, Theresa; Matheus, Friederike; Simeone, Antonio; Hölter, Sabine M; Kühn, Ralf; Weisenhorn, Daniela M Vogt; Wurst, Wolfgang; Prakash, Nilima

    2014-01-01

    The normal cellular organization and layering of the vertebrate cerebellum is established during embryonic and early postnatal development by the interplay of a complex array of genetic and signaling pathways. Disruption of these processes and of the proper layering of the cerebellum usually leads to ataxic behaviors. Here, we analyzed the relative contribution of Fibroblast growth factor receptor 2 (FGFR2)-mediated signaling to cerebellar development in conditional Fgfr2 single mutant mice. We show that during embryonic mouse development, Fgfr2 expression is higher in the anterior cerebellar primordium and excluded from the proliferative ventricular neuroepithelium. Consistent with this finding, conditional Fgfr2 single mutant mice display the most prominent defects in the anterior lobules of the adult cerebellum. In this context, FGFR2-mediated signaling is required for the proper generation of Bergmann glia cells and the correct positioning of these cells within the Purkinje cell layer, and for cell survival in the developing cerebellar primordium. Using cerebellar microexplant cultures treated with an FGFR agonist (FGF9) or antagonist (SU5402), we also show that FGF9/FGFR-mediated signaling inhibits the outward migration of radial glia and Bergmann glia precursors and cells, and might thus act as a positioning cue for these cells. Altogether, our findings reveal the specific functions of the FGFR2-mediated signaling pathway in the generation and positioning of Bergmann glia cells during cerebellar development in the mouse.

  12. FGF/FGFR2 Signaling Regulates the Generation and Correct Positioning of Bergmann Glia Cells in the Developing Mouse Cerebellum

    PubMed Central

    Faus-Kessler, Theresa; Matheus, Friederike; Simeone, Antonio; Hölter, Sabine M.; Kühn, Ralf; Weisenhorn, Daniela M. Vogt.; Wurst, Wolfgang; Prakash, Nilima

    2014-01-01

    The normal cellular organization and layering of the vertebrate cerebellum is established during embryonic and early postnatal development by the interplay of a complex array of genetic and signaling pathways. Disruption of these processes and of the proper layering of the cerebellum usually leads to ataxic behaviors. Here, we analyzed the relative contribution of Fibroblast growth factor receptor 2 (FGFR2)-mediated signaling to cerebellar development in conditional Fgfr2 single mutant mice. We show that during embryonic mouse development, Fgfr2 expression is higher in the anterior cerebellar primordium and excluded from the proliferative ventricular neuroepithelium. Consistent with this finding, conditional Fgfr2 single mutant mice display the most prominent defects in the anterior lobules of the adult cerebellum. In this context, FGFR2-mediated signaling is required for the proper generation of Bergmann glia cells and the correct positioning of these cells within the Purkinje cell layer, and for cell survival in the developing cerebellar primordium. Using cerebellar microexplant cultures treated with an FGFR agonist (FGF9) or antagonist (SU5402), we also show that FGF9/FGFR-mediated signaling inhibits the outward migration of radial glia and Bergmann glia precursors and cells, and might thus act as a positioning cue for these cells. Altogether, our findings reveal the specific functions of the FGFR2-mediated signaling pathway in the generation and positioning of Bergmann glia cells during cerebellar development in the mouse. PMID:24983448

  13. Development of a highly-efficient CHO cell line generation system with engineered SV40E promoter.

    PubMed

    Fan, Lianchun; Kadura, Ibrahim; Krebs, Lara E; Larson, Jeffery L; Bowden, Daniel M; Frye, Christopher C

    2013-12-01

    Chinese hamster ovary (CHO) cells have been one of the most widely used host cells for the manufacture of therapeutic recombinant proteins. An effective and efficient clinical cell line development process, which could quickly identify those rare, high-producing cell lines among a large population of low and non-productive cells, is of considerable interest to speed up biological drug development. In the glutamine synthetase (GS)-CHO expression system, selection of top-producing cell lines is based on controlling the balance between the expression level of GS and the concentration of its specific inhibitor, l-methionine sulfoximine (MSX). The combined amount of GS expressed from plasmids that have been introduced through transfection and the endogenous CHO GS gene determine the stringency and efficiency of selection. Previous studies have shown significant improvement in selection stringency by using GS-knockout CHO cells, which eliminate background GS expression from the endogenous GS gene in CHOK1SV cells. To further improve selection stringency, a series of weakened SV40E promoters have been generated and used to modulate plasmid-based GS expression with the intent of manipulating GS-CHO selection, finely adjusting the balance between GS expression and GS inhibitor (MSX) levels. The reduction of SV40E promoter activities have been confirmed by TaqMan RT-PCR and GFP expression profiling. Significant productivity improvements in both bulk culture and individual clonal cell line have been achieved with the combined use of GS-knockout CHOK1SV cells and weakened SV40E promoters driving GS expression in the current cell line generation process. The selection stringency was significantly increased, as indicated by the shift towards higher distribution of producing-cell populations, even with no MSX added into cell culture medium. The potential applications of weakened SV40E promoter and GS-knockout cells in development of targeted integration and transient CHO

  14. Development of Rear Contact Technologies for Next Generation High-Efficiency Silicon Solar Cells

    SciTech Connect

    Rohatgi, Ajeet; Cooper, Ian

    2012-03-30

    Project Objective: The objective of this program is to develop low-cost high-quality rear contacts and fabricate production-ready high-efficiency monocrystalline (~20%) and multicrystalline (17-18%) silicon solar cells. This efficiency enhancement on thin Si wafers will help achieve the Solar America Initiative goal of a levelized cost of electricity less than 10¢ per kWh by 2015. Background: The efficiency of current c-Si solar cells is strongly dependent on back surface passivation because recent advances in crystal growth and cell processing can produce bulk diffusion lengths greater than the wafer thickness. Improving the rear contact quality realizes three benefits simultaneously: gain in absolute efficiency, ability to use lower quality thin wafers, and better Si utilization. In this project, we will investigate and develop four novel back contact technologies that can lower the back surface recombination velocity (BSRV) and enhance the back surface reflectance (BSR). These rear contact technologies include (a) novel dielectric passivation of the rear surface (b) local contact window opening through a dielectric by screen printing or laser patterning (c) a novel boron diffusion process for p+ back surface field (B-BSF) and (d) a-Si passivation of the p-type rear Si surface in conjunction with screen printed front contacts. Our device modeling and analysis shows that these technologies can raise production-ready large area cell efficiencies in our laboratory from 17.5-18.0% to ~20.0% and expedite their commercialization. These rear contact technologies will allow the use of thin Si wafers (100-150 μm) without any wafer warpage or compromise in cell efficiency.

  15. Microgravity, stem cells, and embryonic development: challenges and opportunities for 3D tissue generation

    NASA Astrophysics Data System (ADS)

    Andreazzoli, Massimiliano; Angeloni, Debora; Broccoli, Vania; Demontis, Gian C.

    2017-04-01

    Space is a challenging environment for the human body, due to the combined effects of reduced gravity (microgravity) and cosmic radiation. Known effects of microgravity range from the blood redistribution that affects the cardiovascular system and the eye to muscle wasting, bone loss, anemia and immune depression. About cosmic radiation, the shielding provided by the spaceship hull is far less efficient than that afforded at ground level by the combined effects of the Earth atmosphere and magnetic field. The eye and its nervous layer (the retina) are affected by both microgravity and heavy ions exposure. Considering the importance of sight for long-term manned flights, visual research aimed at devising measures to protect the eye from environmental conditions of the outer space represents a special challenge to meet. In this review we focus on the impact of microgravity on embryonic development, discussing the roles of mechanical forces in the context of the neutral buoyancy the embryo experiences in the womb. At variance with its adverse effects on the adult human body, simulated microgravity may provide a unique tool for understanding the biomechanical events involved in the development and assembly in vitro of three-dimensional (3D) ocular tissues. Prospective benefits are the development of novel safety measures to protect the human eye from cosmic radiation in microgravity during long-term manned spaceflights in the outer space, as well as the generation of human 3D-retinas with its supporting structures to develop innovative and effective therapeutic options for degenerative eye diseases.

  16. Development of Species-Specific Ah Receptor-Responsive Third Generation CALUX Cell Lines with Increased Sensitivity and Responsiveness

    PubMed Central

    Brennan, Jennifer C.; He, Guochun; Tsutsumi, Tomoaki; Zhao, Jing; Wirth, Ed; Fulton, Michael H.; Denison, Michael S.

    2016-01-01

    The Ah receptor (AhR)-responsive CALUX (chemically-activated luciferase expression) cell bioassay is commonly used for rapid screening of samples for the presence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin), dioxin-like compounds, and AhR agonists/antagonists. By increasing the number of AhR DNA recognition sites (dioxin responsive elements), we previously generated a novel third generation (G3) recombinant AhR-responsive mouse CALUX cell line (H1L7.5c3) with significantly enhanced sensitivity and response to DLCs compared to existing AhR-CALUX cell bioassays. However, the elevated background luciferase activity of these cells and the absence of comparable G3 cell lines derived from other species have limited their utility for screening purposes. Here, we describe the development and characterization of species-specific G3 recombinant AhR-responsive CALUX cell lines (rat, human, and guinea pig) that exhibit significantly improved sensitivity and dramatically increased TCDD induction response. The low background luciferase activity, low minimal detection limit (0.1 pM TCDD) and enhanced induction response of the rat G3 cell line (H4L7.5c2) over the H1L7.5c3 mouse G3 cells, identifies them as a more optimal cell line for screening purposes. The utility of the new G3 CALUX cell lines were demonstrated by screening sediment extracts and a small chemical compound library for the presence of AhR agonists. The increased sensitivity and response of these new G3 CALUX cell lines will facilitate species-specific analysis of DLCs and AhR agonists in samples with low levels of contamination and/or in small sample volumes. PMID:26366531

  17. Generating human intestinal tissues from pluripotent stem cells to study development and disease

    PubMed Central

    Sinagoga, Katie L; Wells, James M

    2015-01-01

    As one of the largest and most functionally complex organs of the human body, the intestines are primarily responsible for the breakdown and uptake of macromolecules from the lumen and the subsequent excretion of waste from the body. However, the intestine is also an endocrine organ, regulating digestion, metabolism, and feeding behavior. Intricate neuronal, lymphatic, immune, and vascular systems are integrated into the intestine and are required for its digestive and endocrine functions. In addition, the gut houses an extensive population of microbes that play roles in digestion, global metabolism, barrier function, and host–parasite interactions. With such an extensive array of cell types working and performing in one essential organ, derivation of functional intestinal tissues from human pluripotent stem cells (PSCs) represents a significant challenge. Here we will discuss the intricate developmental processes and cell types that are required for assembly of this highly complex organ and how embryonic processes, particularly morphogenesis, have been harnessed to direct differentiation of PSCs into 3-dimensional human intestinal organoids (HIOs) in vitro. We will further describe current uses of HIOs in development and disease research and how additional tissue complexity might be engineered into HIOs for better functionality and disease modeling. PMID:25792515

  18. Generating human intestinal tissues from pluripotent stem cells to study development and disease.

    PubMed

    Sinagoga, Katie L; Wells, James M

    2015-05-05

    As one of the largest and most functionally complex organs of the human body, the intestines are primarily responsible for the breakdown and uptake of macromolecules from the lumen and the subsequent excretion of waste from the body. However, the intestine is also an endocrine organ, regulating digestion, metabolism, and feeding behavior. Intricate neuronal, lymphatic, immune, and vascular systems are integrated into the intestine and are required for its digestive and endocrine functions. In addition, the gut houses an extensive population of microbes that play roles in digestion, global metabolism, barrier function, and host-parasite interactions. With such an extensive array of cell types working and performing in one essential organ, derivation of functional intestinal tissues from human pluripotent stem cells (PSCs) represents a significant challenge. Here we will discuss the intricate developmental processes and cell types that are required for assembly of this highly complex organ and how embryonic processes, particularly morphogenesis, have been harnessed to direct differentiation of PSCs into 3-dimensional human intestinal organoids (HIOs) in vitro. We will further describe current uses of HIOs in development and disease research and how additional tissue complexity might be engineered into HIOs for better functionality and disease modeling.

  19. Fuel cell generator energy dissipator

    DOEpatents

    Veyo, Stephen Emery; Dederer, Jeffrey Todd; Gordon, John Thomas; Shockling, Larry Anthony

    2000-01-01

    An apparatus and method are disclosed for eliminating the chemical energy of fuel remaining in a fuel cell generator when the electrical power output of the fuel cell generator is terminated. During a generator shut down condition, electrically resistive elements are automatically connected across the fuel cell generator terminals in order to draw current, thereby depleting the fuel

  20. Multiple Exciton Generation Solar Cells

    SciTech Connect

    Luther, J. M.; Semonin, O. E.; Beard, M. C.; Gao, J.; Nozik, A. J.

    2012-01-01

    Heat loss is the major factor limiting traditional single junction solar cells to a theoretical efficiency of 32%. Multiple Exciton Generation (MEG) enables efficient use of the solar spectrum yielding a theoretical power conversion efficiency of 44% in solar cells under 1-sun conditions. Quantum-confined semiconductors have demonstrated the ability to generate multiple carriers but present-day materials deliver efficiencies far below the SQ limit of 32%. Semiconductor quantum dots of PbSe and PbS provide an active testbed for developing high-efficiency, inexpensive solar cells benefitting from quantum confinement effects. Here, we will present recent work of solar cells employing MEG to yield external quantum efficiencies exceeding 100%.

  1. A role for TREK1 in generating the slow afterhyperpolarization in developing starburst amacrine cells

    PubMed Central

    Ford, Kevin J.; Arroyo, David A.; Kay, Jeremy N.; Lloyd, Eric E.; Bryan, Robert M.; Sanes, Joshua R.

    2013-01-01

    Slow afterhyperpolarizations (sAHPs) play an important role in establishing the firing pattern of neurons that in turn influence network activity. sAHPs are mediated by calcium-activated potassium channels. However, the molecular identity of these channels and the mechanism linking calcium entry to their activation are still unknown. Here we present several lines of evidence suggesting that the sAHPs in developing starburst amacrine cells (SACs) are mediated by two-pore potassium channels. First, we use whole cell and perforated patch voltage clamp recordings to characterize the sAHP conductance under different pharmacological conditions. We find that this conductance was calcium dependent, reversed at EK, blocked by barium, insensitive to apamin and TEA, and activated by arachidonic acid. In addition, pharmacological inhibition of calcium-activated phosphodiesterase reduced the sAHP. Second, we performed gene profiling on isolated SACs and found that they showed strong preferential expression of the two-pore channel gene kcnk2 that encodes TREK1. Third, we demonstrated that TREK1 knockout animals exhibited an altered frequency of retinal waves, a frequency that is set by the sAHPs in SACs. With these results, we propose a model in which depolarization-induced decreases in cAMP lead to disinhibition of the two-pore potassium channels and in which the kinetics of this biochemical pathway dictate the slow activation and deactivation of the sAHP conductance. Our model offers a novel pathway for the activation of a conductance that is physiologically important. PMID:23390312

  2. Development of a UBFC biocatalyst fuel cell to generate power and treat industrial wastewaters.

    PubMed

    Sukkasem, Chontisa; Laehlah, Sunee

    2013-10-01

    Agro-industry wastewaters normally contain high levels of organic matter and require suitable treatment before discharge. The use of Microbial fuel cells, a novel wastewater treatment, can provide advantages over existing treatment methods. In this study, an up-flow bio-filter circuit (UBFC) for treating wastewaters without chemical treatment or nutrient supplement, was developed to solve a clogging problem. The optimal conditions included an organic loading rate of 30.0 g COD/L-d, hydraulic retention time of 1.04 day, pH level of 5.6-6.5 and aeration at 2.0 L/min. External resistance of the circuit was tested. COD removal levels of 8.08, 20.1 and 26.67 g COD/L-d were obtained, while fed with sea food, biodiesel and palm oil mill wastewater, respectively. These rates are higher than for conventional technologies. The carbon fiber brush immobilized base increased the performance of the new UBFC by 17.54% over that obtained in a previous study, while the cost was slightly decreased about 4.48%.

  3. MHD generator electrode development

    NASA Astrophysics Data System (ADS)

    Retallick, F. D.; Dietrick, D. L.; Lloyd, I.; Rossing, B. R.; Smith, R.

    1981-08-01

    Metallurgical and engineering understanding of cold metallic electrode alternatives to the continued use of platinum as an anode clad material is discussed. The results of evaluating materials for MHD electrodes through use of a laboratory electrochemical and arc test are presented. Results for standard available materials as well as for some specially fabricated ones are presented. The development of a high temperature (11000 C to 14000 C) electrochemical test is outlined. Initial operation of the Westinghouse Electrode Systems Test Facility (WESTF), since major modification to include a magnet, is reported for a test section designed to operate as a small scale MHD generator and for test sections designed for the purpose of materials test evaluation in the operating MHD plasma environment.

  4. Pore development in carbonized hemoglobin by concurrently generated MgO template for activity enhancement as fuel cell cathode catalyst.

    PubMed

    Maruyama, Jun; Hasegawa, Takahiro; Amano, Taiji; Muramatsu, Yasuji; Gullikson, Eric M; Orikasa, Yuki; Uchimoto, Yoshiharu

    2011-12-01

    Various carbon materials with a characteristic morphology and pore structure have been produced using template methods in which a carbon-template composite is once formed and the characteristic features derived from the template are generated after the template removal. In this study, hemoglobin, which is a natural compound that could be abundantly and inexpensively obtained, was used as the carbon material source to produce a carbonaceous noble-metal-free fuel cell cathode catalyst. Magnesium oxide was used as the template concurrently generated with the hemoglobin carbonization from magnesium acetate mixed with hemoglobin as the starting material mixture to enable pore development for improving the activity of the carbonized hemoglobin for the cathodic oxygen reduction. After removal of the MgO template, the substantially developed pores were generated in the carbonized hemoglobin with an amorphous structure observed by total-electron-yield X-ray absorption. The extended X-ray absorption fine structure at the Fe-K edge indicated that Fe was coordinated with four nitrogen atoms (Fe-N(4) moiety) in the carbonized hemoglobin. The oxygen reduction activity of the carbonized hemoglobin evaluated using rotating disk electrodes was dependent on the pore structure. The highly developed pores led to an improved activity.

  5. Spectroscopic Analysis of Red Fluorescent Proteins and Development of a Microfluidic Cell Sorter for the Generation of Improved Variants

    NASA Astrophysics Data System (ADS)

    Lubbeck, Jennifer L.

    The discovery of the green fluorescent protein (GFP) launched the development of a wide variety of fluorescent protein (FP) mutants whose spectral and photophysical diversity revolutionized in vivo imaging. The excitation and emission spectra of red fluorescent proteins (RFPs), in particular, have been ideally tuned to a window optically favorable for in vivo work. However, their quantum yields, photostabilities and fluorescence intermittency properties require improvement if they are to be broadly employed for low-copy or single-molecule measurements. Attempts to engineer improved RFPs often result in optimization of one photophysical property at the expense of others. We developed a microfluidic-based cytometer for screening HeLa cell-based genetic RFP-libraries simultaneously on the basis of fluorescence lifetime (a proxy for quantum yield), photostability, and brightness. Ten 532 nm excitation beams interrogate each cell in flow. The first is electro-optically modulated (30 MHz) to enable lifetime measurement with phase fluorimetry. The remaining beams act as a pulse sequence for isolating the irreversible photobleaching time constant. Optical-force switching is employed to sort cells based on any combination of the photophysical parameters. Screening with this instrument enables identification of regions of the structure that synergistically affect quantum yield and photostability and the sorting capability provides a new tool for accelerating the development of next generation RFPs.

  6. Differential inhibition onto developing and mature granule cells generates high-frequency filters with variable gain

    PubMed Central

    Pardi, María Belén; Ogando, Mora Belén; Schinder, Alejandro F; Marin-Burgin, Antonia

    2015-01-01

    Adult hippocampal neurogenesis provides the dentate gyrus with heterogeneous populations of granule cells (GC) originated at different times. The contribution of these cells to information encoding is under current investigation. Here, we show that incoming spike trains activate different populations of GC determined by the stimulation frequency and GC age. Immature GC respond to a wider range of stimulus frequencies, whereas mature GC are less responsive at high frequencies. This difference is dictated by feedforward inhibition, which restricts mature GC activation. Yet, the stronger inhibition of mature GC results in a higher temporal fidelity compared to that of immature GC. Thus, hippocampal inputs activate two populations of neurons with variable frequency filters: immature cells, with wide‐range responses, that are reliable transmitters of the incoming frequency, and mature neurons, with narrow frequency response, that are precise at informing the beginning of the stimulus, but with a sparse activity. DOI: http://dx.doi.org/10.7554/eLife.08764.001 PMID:26163657

  7. High voltage solar cell power generating system for regulated solar array development

    NASA Technical Reports Server (NTRS)

    Levy, E., Jr.; Hoffman, A. C.

    1973-01-01

    A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kw), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2560 series-connected cells. Each light source consists of twenty 500 watt tungsten iodide lamps providing plus or minus 5 per cent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water cooled plate, a vacuum hold-down system, and air flushing.

  8. Solid oxide fuel cell generator

    DOEpatents

    Di Croce, A. Michael; Draper, Robert

    1993-11-02

    A solid oxide fuel cell generator has a plenum containing at least two rows of spaced apart, annular, axially elongated fuel cells. An electrical conductor extending between adjacent rows of fuel cells connects the fuel cells of one row in parallel with each other and in series with the fuel cells of the adjacent row.

  9. Neuregulin 1 Type II-ErbB Signaling Promotes Cell Divisions Generating Neurons from Neural Progenitor Cells in the Developing Zebrafish Brain.

    PubMed

    Sato, Tomomi; Sato, Fuminori; Kamezaki, Aosa; Sakaguchi, Kazuya; Tanigome, Ryoma; Kawakami, Koichi; Sehara-Fujisawa, Atsuko

    2015-01-01

    Post-mitotic neurons are generated from neural progenitor cells (NPCs) at the expense of their proliferation. Molecular and cellular mechanisms that regulate neuron production temporally and spatially should impact on the size and shape of the brain. While transcription factors such as neurogenin1 (neurog1) and neurod govern progression of neurogenesis as cell-intrinsic mechanisms, recent studies show regulatory roles of several cell-extrinsic or intercellular signaling molecules including Notch, FGF and Wnt in production of neurons/neural progenitor cells from neural stem cells/radial glial cells (NSCs/RGCs) in the ventricular zone (VZ). However, it remains elusive how production of post-mitotic neurons from neural progenitor cells is regulated in the sub-ventricular zone (SVZ). Here we show that newborn neurons accumulate in the basal-to-apical direction in the optic tectum (OT) of zebrafish embryos. While neural progenitor cells are amplified by mitoses in the apical ventricular zone, neurons are exclusively produced through mitoses of neural progenitor cells in the sub-basal zone, later in the sub-ventricular zone, and accumulate apically onto older neurons. This neurogenesis depends on Neuregulin 1 type II (NRG1-II)-ErbB signaling. Treatment with an ErbB inhibitor, AG1478 impairs mitoses in the sub-ventricular zone of the optic tectum. Removal of AG1478 resumes sub-ventricular mitoses without precedent mitoses in the apical ventricular zone prior to basal-to-apical accumulation of neurons, suggesting critical roles of ErbB signaling in mitoses for post-mitotic neuron production. Knockdown of NRG1-II impairs both mitoses in the sub-basal/sub-ventricular zone and the ventricular zone. Injection of soluble human NRG1 into the developing brain ameliorates neurogenesis of NRG1-II-knockdown embryos, suggesting a conserved role of NRG1 as a cell-extrinsic signal. From these results, we propose that NRG1-ErbB signaling stimulates cell divisions generating neurons from

  10. The development of innate lymphoid cells requires TOX-dependent generation of a common innate lymphoid cell progenitor.

    PubMed

    Seehus, Corey R; Aliahmad, Parinaz; de la Torre, Brian; Iliev, Iliyan D; Spurka, Lindsay; Funari, Vincent A; Kaye, Jonathan

    2015-06-01

    Diverse innate lymphoid cell (ILC) subtypes have been defined on the basis of effector function and transcription factor expression. ILCs derive from common lymphoid progenitors, although the transcriptional pathways that lead to ILC-lineage specification remain poorly characterized. Here we found that the transcriptional regulator TOX was required for the in vivo differentiation of common lymphoid progenitors into ILC lineage-restricted cells. In vitro modeling demonstrated that TOX deficiency resulted in early defects in the survival or proliferation of progenitor cells, as well as ILC differentiation at a later stage. In addition, comparative transcriptome analysis of bone marrow progenitors revealed that TOX-deficient cells failed to upregulate many genes of the ILC program, including genes that are targets of Notch, which indicated that TOX is a key determinant of early specification to the ILC lineage.

  11. Solar Power Generation Development

    SciTech Connect

    Robert L. Johnson Jr.; Gary E. Carver

    2011-10-28

    This project centered on creating a solar cell prototype enabling significant reductions in module cost and increases in module efficiency. Low cost was addressed by using plentiful organic materials that only comprise 16% of the total module cost, and by leveraging building integrated PV concepts that reduce the cost of key module components to zero. High efficiency was addressed by implementing multiband organic PV, low cost spectral splitting, and possibly integrating photovoltaic and photothermal mechanisms. This research has contributed to the design of multiband organic PV, and the sealing of organic PV cells. If one assumes that the aggregate multiband efficiency can reach 12%, projected cost would be $0.97/W. If the sealing technology enables 10 to 20 year lifetimes, the LCOE will match that of domestic coal. The final report describes progress towards these goals.

  12. Solid oxide fuel cell generator

    DOEpatents

    Draper, R.; George, R.A.; Shockling, L.A.

    1993-04-06

    A solid oxide fuel cell generator has a pair of spaced apart tubesheets in a housing. At least two intermediate barrier walls are between the tubesheets and define a generator chamber between two intermediate buffer chambers. An array of fuel cells have tubes with open ends engaging the tubesheets. Tubular, axially elongated electrochemical cells are supported on the tubes in the generator chamber. Fuel gas and oxidant gas are preheated in the intermediate chambers by the gases flowing on the other side of the tubes. Gas leakage around the tubes through the tubesheets is permitted. The buffer chambers reentrain the leaked fuel gas for reintroduction to the generator chamber.

  13. Solid oxide fuel cell generator

    DOEpatents

    Draper, Robert; George, Raymond A.; Shockling, Larry A.

    1993-01-01

    A solid oxide fuel cell generator has a pair of spaced apart tubesheets in a housing. At least two intermediate barrier walls are between the tubesheets and define a generator chamber between two intermediate buffer chambers. An array of fuel cells have tubes with open ends engaging the tubesheets. Tubular, axially elongated electrochemical cells are supported on the tubes in the generator chamber. Fuel gas and oxidant gas are preheated in the intermediate chambers by the gases flowing on the other side of the tubes. Gas leakage around the tubes through the tubesheets is permitted. The buffer chambers reentrain the leaked fuel gas for reintroduction to the generator chamber.

  14. CRISPR/Cas9-generated p47phox-deficient cell line for Chronic Granulomatous Disease gene therapy vector development

    PubMed Central

    Wrona, Dominik; Siler, Ulrich; Reichenbach, Janine

    2017-01-01

    Development of gene therapy vectors requires cellular models reflecting the genetic background of a disease thus allowing for robust preclinical vector testing. For human p47phox-deficient chronic granulomatous disease (CGD) vector testing we generated a cellular model using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 to introduce a GT-dinucleotide deletion (ΔGT) mutation in p47phox encoding NCF1 gene in the human acute myeloid leukemia PLB-985 cell line. CGD is a group of hereditary immunodeficiencies characterized by impaired respiratory burst activity in phagocytes due to a defective phagocytic nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. In Western countries autosomal-recessive p47phox-subunit deficiency represents the second largest CGD patient cohort with unique genetics, as the vast majority of p47phox CGD patients carries ΔGT deletion in exon two of the NCF1 gene. The established PLB-985 NCF1 ΔGT cell line reflects the most frequent form of p47phox-deficient CGD genetically and functionally. It can be differentiated to granulocytes efficiently, what creates an attractive alternative to currently used iPSC models for rapid testing of novel gene therapy approaches. PMID:28287132

  15. CRISPR/Cas9-generated p47(phox)-deficient cell line for Chronic Granulomatous Disease gene therapy vector development.

    PubMed

    Wrona, Dominik; Siler, Ulrich; Reichenbach, Janine

    2017-03-13

    Development of gene therapy vectors requires cellular models reflecting the genetic background of a disease thus allowing for robust preclinical vector testing. For human p47(phox)-deficient chronic granulomatous disease (CGD) vector testing we generated a cellular model using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 to introduce a GT-dinucleotide deletion (ΔGT) mutation in p47(phox) encoding NCF1 gene in the human acute myeloid leukemia PLB-985 cell line. CGD is a group of hereditary immunodeficiencies characterized by impaired respiratory burst activity in phagocytes due to a defective phagocytic nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. In Western countries autosomal-recessive p47(phox)-subunit deficiency represents the second largest CGD patient cohort with unique genetics, as the vast majority of p47(phox) CGD patients carries ΔGT deletion in exon two of the NCF1 gene. The established PLB-985 NCF1 ΔGT cell line reflects the most frequent form of p47(phox)-deficient CGD genetically and functionally. It can be differentiated to granulocytes efficiently, what creates an attractive alternative to currently used iPSC models for rapid testing of novel gene therapy approaches.

  16. Smurf-mediated differential proteolysis generates dynamic BMP signaling in germline stem cells during Drosophila testis development.

    PubMed

    Chang, Yi-Jie; Pi, Haiwei; Hsieh, Chang-Che; Fuller, Margaret T

    2013-11-01

    Germline stem cells (GSCs) produce gametes throughout the reproductive life of many animals, and intensive studies have revealed critical roles of BMP signaling to maintain GSC self-renewal in Drospophila adult gonads. Here, we show that BMP signaling is downregulated as testes develop and this regulation controls testis growth, stem cell number, and the number of spermatogonia divisions. Phosphorylated Mad (pMad), the activated Drosophila Smad in germ cells, was restricted from anterior germ cells to GSCs and hub-proximal cells during early larval development. pMad levels in GSCs were then dramatically downregulated from early third larval instar (L3) to late L3, and maintained at low levels in pupal and adult GSCs. The spatial restriction and temporal down-regulation of pMad, reflecting the germ cell response to BMP signaling activity, required action in germ cells of E3 ligase activity of HECT domain protein Smurf. Analyses of Smurf mutant testes and dosage-dependent genetic interaction between Smurf and mad indicated that pMad downregulation was required for both the normal decrease in stem cell number during testis maturation in the pupal stage, and for normal limit of four rounds of spermatogonia cell division for control of germ cell numbers and testis size. Smurf protein was expressed at a constant low level in GSCs and spermatogonia during development. Rescue experiments showed that expression of exogenous Smurf protein in early germ cells promoted pMad downregulation in GSCs in a stage-dependent but concentration-independent manner, suggesting that the competence of Smurf to attenuate response to BMP signaling may be regulated during development. Taken together, our work reveals a critical role for differential attenuation of the response to BMP signaling in GSCs and early germ cells for control of germ cell number and gonad growth during development.

  17. Smurf-mediated differential proteolysis generates dynamic BMP signaling in germline stem cells during Drosophila testis development

    PubMed Central

    Chang, Yi-Jie; Pi, Haiwei; Hsieh, Chang-Che; Fuller, Margaret T.

    2014-01-01

    Germline stem cells (GSCs) produce gametes throughout the reproductive life of many animals, and intensive studies have revealed critical roles of BMP signaling to maintain GSC self-renewal in Drospophila adult gonads. Here, we show that BMP signaling is downregulated as testes develop and this regulation controls testis growth, stem cell number, and the number of spermatogonia divisions. Phosphorylated Mad (pMad), the activated Drosophila Smad in germ cells, was restricted from anterior germ cells to GSCs and hub-proximal cells during early larval development. pMad levels in GSCs were then dramatically downregulated from early third larval instar (L3) to late L3, and maintained at low levels in pupal and adult GSCs. The spatial restriction and temporal down-regulation of pMad, reflecting the germ cell response to BMP signaling activity, required action in germ cells of E3 ligase activity of HECT domain protein Smurf. Analyses of Smurf mutant testes and dosage-dependent genetic interaction between Smurf and mad indicated that pMad down-regulation was required for both the normal decrease in stem cell number during testis maturation in the pupal stage, and for normal limit of four rounds of spermatogonia cell division for control of germ cell numbers and testis size. Smurf protein was expressed at a constant low level in GSCs and spermatogonia during development. Rescue experiments showed that expression of exogenous Smurf protein in early germ cells promoted pMad downregulation in GSCs in a stage-dependent but concentration-independent manner, suggesting that the competence of Smurf to attenuate response to BMP signaling may be regulated during development. Taken together, our work reveals a critical role for differential attenuation of the response to BMP signaling in GSCs and early germ cells for control of germ cell number and gonad growth during development. PMID:23988579

  18. Mapping of the fate of cell lineages generated from cells that express the Wnt4 gene by time-lapse during kidney development.

    PubMed

    Shan, Jingdong; Jokela, Tiina; Skovorodkin, Ilya; Vainio, Seppo

    2010-01-01

    The Wnt4 gene encodes a secreted signaling molecule controlling the development of several organs, such as the kidney, adrenal gland, ovary, mammary gland and pituitary gland. It is thought to act in the embryonic kidney as an auto-inducer of nephrogenesis controlling mesenchyme-to-epithelium transition, and Wnt4-deficient mice die soon after birth, probably of kidney failure. Given the requirement for Wnt4 signaling in the control of organogenesis, the targeting of Cre recombinase under the control of the Wnt4 promoter would provide a valuable tool for fate mapping and functional genomics. We report here on the generation and characterization of a Wnt4(EGFPCre) knock-in allele where the EGFPCre fusion cDNA and Neo selection cassette were targeted into the Wnt4 locus. EGFP-derived fluorescence was observed in the pretubular aggregates of the E14.5 embryonic kidney that normally express Wnt4 mRNA. Characterization of the pattern of recombination of the floxed Rosa26(LacZ) reporter with the Wnt4(EGFPCre) allele revealed that in addition to the embryonic kidney, reporter-derived staining was observed in the embryonic gonad, spinal cord, lung and adrenal gland, i.e. the sites of Wnt4 gene expression. Time-lapse fate mapping of the Wnt4(EGFPCre)-activated yellow fluorescent protein (YFP) from the Rosa26 locus in organ culture revealed that the cells that had expressed the Wnt4 gene contributed to the nephrons, some of the cells around the stalk of the developing ureter and also certain presumptive medullary stromal cells. Moreover, the time-lapse movies suggested that the first few pretubular cell aggregates may not mature into nephrons but instead appear to disintegrate. In association with this, Rosa26(YFP)-positive stromal cells emerge around these disintegrating structures. Such cells may be transient, since their derivatives are neither detected later in the more mature kidney nor is there an overlap of the Wnt4(EGFPCre); Rosa26(LacZ)-marked cells with those of the

  19. A model for the development of human IgD-only B cells: Genotypic analyses suggest their generation in superantigen driven immune responses.

    PubMed

    Seifert, Marc; Steimle-Grauer, Susanne A; Goossens, Tina; Hansmann, Martin-Leo; Bräuninger, Andreas; Küppers, Ralf

    2009-02-01

    Human peripheral blood (PB) B cells expressing only IgD and tonsillar IgD-secreting plasma cells carry highly mutated V(H) genes and show preferential Iglambda usage. To further characterize these peculiar cells and gain insight into their generation, we analysed rearranged V(H) and V(L) genes of single IgD-only lambda(+) PB B cells and IgD(+) plasma cells from four individuals each. We demonstrate that the high somatic hypermutation activity in these cells is not restricted to V(H) genes but also present in V(L) genes. Moreover, not only PB IgD-only B cells, as reported earlier, but also IgD-expressing plasma cells often belong to very large clones. Surprisingly, the V(H)3-30 gene segment was used in each PB donor by >30% of IgD-only cells and in 2 tonsils by >50% of IgD plasma cells, whereas it was used less frequent in other B cells. All these features fit to a model in which IgD-only cells develop in superantigen-driven germinal center reactions, in which B cells are activated by binding of antigens to constant parts of Cdelta and often lambda light chains and the V(H)3-30 segment, and are selected for deletion of Cmu. IgD-only B cells may hence represent a unique B lineage subset generated in response to particular antigens.

  20. Microfluidic fuel cells for energy generation.

    PubMed

    Safdar, M; Jänis, J; Sánchez, S

    2016-08-07

    Sustainable energy generation is of recent interest due to a growing energy demand across the globe and increasing environmental issues caused by conventional non-renewable means of power generation. In the context of microsystems, portable electronics and lab-on-a-chip based (bio)chemical sensors would essentially require fully integrated, reliable means of power generation. Microfluidic-based fuel cells can offer unique advantages compared to conventional fuel cells such as high surface area-to-volume ratio, ease of integration, cost effectiveness and portability. Here, we summarize recent developments which utilize the potential of microfluidic devices for energy generation.

  1. Development of low-cost technology for the next generation of high efficiency solar cells composed of earth abundant elements

    SciTech Connect

    Agrawal, Rakesh

    2014-09-28

    The development of renewable, affordable, and environmentally conscious means of generating energy on a global scale represents a grand challenge of our time. Due to the “permanence” of radiation from the sun, solar energy promises to remain a viable and sustainable power source far into the future. Established single-junction photovoltaic technologies achieve high power conversion efficiencies (pce) near 20% but require complicated manufacturing processes that prohibit the marriage of large-scale throughput (e.g. on the GW scale), profitability, and quality control. Our approach to this problem begins with the synthesis of nanocrystals of semiconductor materials comprising earth abundant elements and characterized by material and optoelectronic properties ideal for photovoltaic applications, namely Cu2ZnSn(S,Se)4 (CZTSSe). Once synthesized, such nanocrystals are formulated into an ink, coated onto substrates, and processed into completed solar cells in such a way that enables scale-up to high throughput, roll-to-roll manufacturing processes. This project aimed to address the major limitation to CZTSSe solar cell pce’s – the low open-circuit voltage (Voc) reported throughout literature for devices comprised of this material. Throughout the project significant advancements have been made in fundamental understanding of the CZTSSe material and device limitations associated with this material system. Additionally, notable improvements have been made to our nanocrystal based processing technique to alleviate performance limitations due to the identified device limitations. Notably, (1) significant improvements have been made in reducing intra- and inter-nanoparticle heterogeneity, (2) improvements in device performance have been realized with novel cation substitution in Ge-alloyed CZTGeSSe absorbers, (3) systematic analysis of absorber sintering has been conducted to optimize the selenization process for large grain CZTSSe absorbers, (4) novel electrical

  2. Electricity generation from cattle dung using microbial fuel cell technology during anaerobic acidogenesis and the development of microbial populations.

    PubMed

    Zhao, Guang; Ma, Fang; Wei, Li; Chua, Hong; Chang, Chein-Chi; Zhang, Xiao-Jun

    2012-09-01

    A microbial fuel cell (MFC) was constructed to investigate the possible generation of electricity using cattle dung as a substrate. After 30 days of operation, stable electricity was generated, and the maximum volumetric power density was 0.220 W/m(3). The total chemical oxygen demand (TCOD) removal and coulombic efficiency (CE) of the MFC reached 73.9±1.8% and 2.79±0.6%, respectively, after 120 days of operation. Acetate was the main metabolite in the anolyte, and other volatile fatty acids (VFAs) (propionate and butyrate) were present in minor amounts. The PCR-DGGE analysis indicated that the following five groups of microbes were present: Proteobacteria, Bacteroides, Chloroflexi, Actinobacteria and Firmicutes. Proteobacteria and Firmicutes were the dominant phyla in the sample; specifically, 36.3% and 24.2% of the sequences obtained were Proteobacteria and Firmicutes, respectively. Clostridium sp., Pseudomonas luteola and Ochrobactrum pseudogrignonense were the most dominant groups during the electricity generation process. The diversity of archaea dramatically decreased after 20 days of operation. The detected archaea were hydrogenotrophic methanogens, and the Methanobacterium genus disappeared during the periods of stable electricity generation via acidogenesis.

  3. Universal signal generator for dynamic cell stimulation.

    PubMed

    Piehler, Andreas; Ghorashian, Navid; Zhang, Ce; Tay, Savaş

    2017-06-27

    Dynamic cell stimulation is a powerful technique for probing gene networks and for applications in stem cell differentiation, immunomodulation and signaling. We developed a robust and flexible method and associated microfluidic devices to generate a wide-range of precisely formulated dynamic chemical signals to stimulate live cells and measure their dynamic response. This signal generator is capable of digital to analog conversion (DAC) through combinatoric selection of discrete input concentrations, and outperforms existing methods by both achievable resolution, dynamic range and simplicity in design. It requires no calibration, has minimal space requirements and can be easily integrated into microfluidic cell culture devices. The signal generator hardware and software we developed allows to choose the waveform, period and amplitude of chemical input signals and features addition of well-defined chemical noise to study the role of stochasticity in cellular information processing.

  4. The Development of Fuel Cell Technology for Electric Power Generation - From Spacecraft Applications to the Hydrogen Economy

    NASA Technical Reports Server (NTRS)

    Scott, John H.

    2005-01-01

    The fuel cell uses a catalyzed reaction between a fuel and an oxidizer to directly produce electricity. Its high theoretical efficiency and low temperature operation made it a subject of much study upon its invention ca. 1900, but its relatively high life cycle costs kept it as "solution in search of a problem" for its first half century. The first problem for which fuel cells presented a cost effective solution was, starting in the 1960's that of a power source for NASA's manned spacecraft. NASA thus invested, and continues to invest, in the development of fuel cell power plants for this application. However, starting in the mid-1990's, prospective environmental regulations have driven increased governmental and industrial interest in "green power" and the "Hydrogen Economy." This has in turn stimulated greatly increased investment in fuel cell development for a variety of terrestrial applications. This investment is bringing about notable advances in fuel cell technology, but these advances are often in directions quite different from those needed for NASA spacecraft applications. This environment thus presents both opportunities and challenges for NASA's manned space program.

  5. Oxygen Generation Assembly Technology Development

    NASA Technical Reports Server (NTRS)

    Bagdigian, Robert; Cloud, Dale

    1999-01-01

    Hamilton Standard Space Systems International (HSSI) is under contract to NASA Marshall Space Flight Center (MSFC) to develop an Oxygen Generation Assembly (OGA) for the International Space Station (ISS). The International Space Station Oxygen Generation Assembly (OGA) electrolyzes potable water from the Water Recovery System (WRS) to provide gaseous oxygen to the Space Station module atmosphere. The OGA produces oxygen for metabolic consumption by crew and biological specimens. The OGA also replenishes oxygen lost by experiment ingestion, airlock depressurization, CO2 venting, and leakage. As a byproduct, gaseous hydrogen is generated. The hydrogen will be supplied at a specified pressure range above ambient to support future utilization. Initially, the hydrogen will be vented overboard to space vacuum. This paper describes the OGA integration into the ISS Node 3. It details the development history supporting the design and describes the OGA System characteristics and its physical layout.

  6. Oxygen Generation Assembly Technology Development

    NASA Technical Reports Server (NTRS)

    Bagdigian, Robert; Cloud, Dale

    1999-01-01

    Hamilton Standard Space Systems International (HSSI) is under contract to NASA Marshall Space Flight Center (MSFC) to develop an Oxygen Generation Assembly (OGA) for the International Space Station (ISS). The International Space Station Oxygen Generation Assembly (OGA) electrolyzes potable water from the Water Recovery System (WRS) to provide gaseous oxygen to the Space Station module atmosphere. The OGA produces oxygen for metabolic consumption by crew and biological specimens. The OGA also replenishes oxygen lost by experiment ingestion, airlock depressurization, CO2 venting, and leakage. As a byproduct, gaseous hydrogen is generated. The hydrogen will be supplied at a specified pressure range above ambient to support future utilization. Initially, the hydrogen will be vented overboard to space vacuum. This paper describes the OGA integration into the ISS Node 3. It details the development history supporting the design and describes the OGA System characteristics and its physical layout.

  7. Development and Demonstration of a New Generation High Efficiency 10kW Stationary Fuel Cell System

    SciTech Connect

    Howell, Thomas Russell

    2013-04-30

    The overall project objective is to develop and demonstrate a polymer electrolyte membrane fuel cell combined heat and power (PEMFC CHP) system that provides the foundation for commercial, mass produced units which achieve over 40% electrical efficiency (fuel to electric conversion) from 50-100% load, greater than 70% overall efficiency (fuel to electric energy + usable waste heat energy conversion), have the potential to achieve 40,000 hours durability on all major process components, and can be produced in high volumes at under $400/kW (revised to $750/kW per 2011 DOE estimates) capital cost.

  8. Islet cell development.

    PubMed

    Rojas, Anabel; Khoo, Adrian; Tejedo, Juan R; Bedoya, Francisco J; Soria, Bernat; Martín, Franz

    2010-01-01

    Over the last years, there has been great success in driving stem cells toward insulin-expressing cells. However, the protocols developed to date have some limitations, such as low reliability and low insulin production. The most successful protocols used for generation of insulin-producing cells from stem cells mimic in vitro pancreatic organogenesis by directing the stem cells through stages that resemble several pancreatic developmental stages. Islet cell fate is coordinated by a complex network of inductive signals and regulatory transcription factors that, in a combinatorial way, determine pancreatic organ specification, differentiation, growth, and lineage. Together, these signals and factors direct the progression from multipotent progenitor cells to mature pancreatic cells. Later in development and adult life, several of these factors also contribute to maintain the differentiated phenotype of islet cells. A detailed understanding of the processes that operate in the pancreas during embryogenesis will help us to develop a suitable source of cells for diabetes therapy. In this chapter, we will discuss the main transcription factors involved in pancreas specification and beta-cell formation.

  9. Discharge cell for ozone generator

    SciTech Connect

    Nakatsuka, Suguru

    2000-01-01

    A discharge cell for use in an ozone generator is provided which can suppress a time-related reduction in ozone concentration without adding a catalytic gas such as nitrogen gas to oxygen gas as a raw material gas. The discharge cell includes a pair of electrodes disposed in an opposed spaced relation with a discharge space therebetween, and a dielectric layer of a three-layer structure consisting of three ceramic dielectric layers successively stacked on at least one of the electrodes, wherein a first dielectric layer of the dielectric layer contacting the one electrode contains no titanium dioxide, wherein a second dielectric layer of the dielectric layer exposed to the discharge space contains titanium dioxide in a metal element ratio of not lower than 10 wt %.

  10. Discharge cell for ozone generator

    SciTech Connect

    Nakatsuka, Suguru

    2000-04-04

    A discharge cell for use in an ozone generator is provided which can suppress a time-related reduction in ozone concentration without adding a catalytic gas such as nitrogen gas to oxygen gas as a raw material gas. The discharge cell includes a pair of electrodes disposed in an opposed spaced relation with a discharge space there between, and a dielectric layer of a three-layer structure consisting of three ceramic dielectric layers successively stacked on at least one of the electrodes, wherein a first dielectric layer of the dielectric layer contacting the one electrode contains no titanium dioxide, wherein a second dielectric layer of the dielectric layer exposed to the discharge space contains titanium dioxide in a metal element ratio of not lower than 10 wt%.

  11. Strategies to generate induced pluripotent stem cells.

    PubMed

    Hayes, Michael; Zavazava, Nicholas

    2013-01-01

    The isolation of embryonic stem cells (ESCs) has furthered our understanding of normal embryonic development and fueled the progression of stem cell derived therapies. However, the generation of ESCs requires the destruction of an embryo, making the use of these cells ethically controversial. In 2006 the Yamanaka group overcame this ethical controversy when they described a protocol whereby somatic cells could be dedifferentiated into a pluripotent state following the transduction of a four transcription factor cocktail. Following this initial study numerous groups have described protocols to generate induced pluripotent stem cells (iPSCs). These protocols have simplified the reprogramming strategy by employing polycistronic reprogramming cassettes and flanking such polycistronic cassettes with loxP or piggyBac recognition sequences. Thus, these strategies allow for excision of the entire transgene cassette, limiting the potential for the integration of exogenous transgenes to have detrimental effect. Others have prevented the potentially deleterious effects of integrative reprogramming strategies by using non-integrating adenoviral vectors, traditional recombinant DNA transfection, transfection of minicircle DNA, or transfection of episomally maintained EBNA1/OriP plasmids. Interestingly, transfection of mRNA or miRNA has also been shown to be capable of reprogramming cells, and multiple groups have developed protocols using cell penetrating peptide tagged reprogramming factors to de-differentiate somatic cells in the absence of exogenous nucleic acid. Despite the numerous different reprogramming strategies that have been developed, the reprogramming process remains extremely inefficient. To overcome this inefficiency multiple groups have successfully used small molecules such as valproic acid, sodium butyrate, PD0325901, and others to generate iPSCs.The fast paced field of cellular reprogramming has recently produced protocols to generate iPSCs using non

  12. Generator configuration for solid oxide fuel cells

    DOEpatents

    Reichner, Philip

    1989-01-01

    Disclosed are improvements in a solid oxide fuel cell generator 1 having a multiplicity of electrically connected solid oxide fuel cells 2, where a fuel gas is passed over one side of said cells and an oxygen-containing gas is passed over the other side of said cells resulting in the generation of heat and electricity. The improvements comprise arranging the cells in the configuration of a circle, a spiral, or folded rows within a cylindrical generator, and modifying the flow rate, oxygen concentration, and/or temperature of the oxygen-containing gases that flow to those cells that are at the periphery of the generator relative to those cells that are at the center of the generator. In these ways, a more uniform temperature is obtained throughout the generator.

  13. Development of an automated closed system for generation of human lymphokine-activated killer (LAK) cells for use in adoptive immunotherapy.

    PubMed

    Muul, L M; Nason-Burchenal, K; Carter, C S; Cullis, H; Slavin, D; Hyatt, C; Director, E P; Leitman, S F; Klein, H G; Rosenberg, S A

    1987-08-03

    Immunotherapy utilizing the adoptive transfer of lymphokine-activated killer (LAK) cells in conjunction with recombinant interleukin-2 (IL-2) can mediate tumor regression in some patients with advanced cancer. The activation of large numbers of LAK cells was performed in roller bottles in a research laboratory setting and required meticulous aseptic technique, at least one skilled technician per patient and one laminar flow hood per patient. To reduce the complexity and expense of LAK cell generation for human immunotherapy trials we have developed a closed-system automated procedure using a continuous flow blood cell separator. PBL were obtained by standard apheresis techniques. Platelets and plasma were elutriated using countercentrifugal flow of saline in the cell separator machine. The washed PBL were underlaid with Ficoll-Hypaque (FH) in the original separation bag. Lymphocytes were then flushed into a collection bag where they were concentrated and washed with 2 liters of saline. Mean recovery from the automated FH technique was 54.6 +/- 4.3% compared to 62.3 +/- 4.0% using manual methods in 50 ml tubes (P greater than 0.05). Cells were diluted in the collection bag with RPMI 1640 +/- 2% human AB serum and could be dispensed in an automated fashion to polyolefin bags via a sample port with 1000-1500 U/ml IL-2. After 3-4 days of culture in 5% CO2 at 37 degrees C, activated cells from the bags were harvested and washed in a closed system using the continuous flow cell separator. Cell yield from the harvest was 79.2 +/- 5.4% in the automated system compared to 64.9 +/- 5.0% in the standard procedure using manual harvest of roller bottles (P less than 0.01). Lytic capacity of the cells against fresh human tumor in a 4 h 51Cr release assay was equivalent in cells processed either by the automated or the conventional manual method. The advantages of a closed system include decreased potential for microbial contamination and reduced labor and capital equipment costs

  14. Generating cartilage repair from pluripotent stem cells.

    PubMed

    Cheng, Aixin; Hardingham, Timothy E; Kimber, Susan J

    2014-08-01

    The treatment of degeneration and injury of articular cartilage has been very challenging for scientists and surgeons. As an avascular and hypocellular tissue, cartilage has a very limited capacity for self-repair. Chondrocytes are the only cell type in cartilage, in which they are surrounded by the extracellular matrix that they secrete and assemble. Autologous chondrocyte implantation for cartilage defects has achieved good results, but the limited resources and complexity of the procedure have hindered wider application. Stem cells form an alternative to chondrocytes as a source of chondrogenic cells due to their ability to proliferate extensively while retaining the potential for differentiation. Adult stem cells such as mesenchymal stem cells have been differentiated into chondrocytes, but the limitations in their proliferative ability and the heterogeneous cell population hinder their adoption as a prime alternative source for generating chondrocytes. Human embryonic stem cells (hESCs) are attractive as candidates for cell replacement therapy because of their unlimited self-renewal and ability for differentiation into mesodermal derivatives as well as other lineages. In this review, we focus on current protocols for chondrogenic differentiation of ESCs, in particular the chemically defined culture system developed in our lab that could potentially be adapted for clinical application.

  15. Isolation and generation of human dendritic cells.

    PubMed

    Nair, Smita; Archer, Gerald E; Tedder, Thomas F

    2012-11-01

    Dendritic cells are highly specialized antigen-presenting cells (APC), which may be isolated or generated from human blood mononuclear cells. Although mature blood dendritic cells normally represent ∼0.2% of human blood mononuclear cells, their frequency can be greatly increased using the cell enrichment methods described in this unit. More highly purified dendritic cell preparations can be obtained from these populations by sorting of fluorescence-labeled cells. Alternatively, dendritic cells can be generated from monocytes by culture with the appropriate cytokines, as described here. In addition, a negative selection approach is provided that may be employed to generate cell preparations that have been depleted of dendritic cells to be used for comparison in functional studies.

  16. Functional Neuronal Cells Generated by Human Parthenogenetic Stem Cells

    PubMed Central

    Ahmad, Ruhel; Wolber, Wanja; Eckardt, Sigrid; Koch, Philipp; Schmitt, Jessica; Semechkin, Ruslan; Geis, Christian; Heckmann, Manfred; Brüstle, Oliver; McLaughlin, John K.; Sirén, Anna-Leena; Müller, Albrecht M.

    2012-01-01

    Parent of origin imprints on the genome have been implicated in the regulation of neural cell type differentiation. The ability of human parthenogenetic (PG) embryonic stem cells (hpESCs) to undergo neural lineage and cell type-specific differentiation is undefined. We determined the potential of hpESCs to differentiate into various neural subtypes. Concurrently, we examined DNA methylation and expression status of imprinted genes. Under culture conditions promoting neural differentiation, hpESC-derived neural stem cells (hpNSCs) gave rise to glia and neuron-like cells that expressed subtype-specific markers and generated action potentials. Analysis of imprinting in hpESCs and in hpNSCs revealed that maternal-specific gene expression patterns and imprinting marks were generally maintained in PG cells upon differentiation. Our results demonstrate that despite the lack of a paternal genome, hpESCs generate proliferating NSCs that are capable of differentiation into physiologically functional neuron-like cells and maintain allele-specific expression of imprinted genes. Thus, hpESCs can serve as a model to study the role of maternal and paternal genomes in neural development and to better understand imprinting-associated brain diseases. PMID:22880113

  17. Fuel dissipater for pressurized fuel cell generators

    DOEpatents

    Basel, Richard A.; King, John E.

    2003-11-04

    An apparatus and method are disclosed for eliminating the chemical energy of fuel remaining in a pressurized fuel cell generator (10) when the electrical power output of the fuel cell generator is terminated during transient operation, such as a shutdown; where, two electrically resistive elements (two of 28, 53, 54, 55) at least one of which is connected in parallel, in association with contactors (26, 57, 58, 59), a multi-point settable sensor relay (23) and a circuit breaker (24), are automatically connected across the fuel cell generator terminals (21, 22) at two or more contact points, in order to draw current, thereby depleting the fuel inventory in the generator.

  18. In Vitro and In Vivo Development of Horse Cloned Embryos Generated with iPSCs, Mesenchymal Stromal Cells and Fetal or Adult Fibroblasts as Nuclear Donors

    PubMed Central

    Olivera, Ramiro; Moro, Lucia Natalia; Jordan, Roberto; Luzzani, Carlos; Miriuka, Santiago; Radrizzani, Martin; Donadeu, F. Xavier; Vichera, Gabriel

    2016-01-01

    The demand for equine cloning as a tool to preserve high genetic value is growing worldwide; however, nuclear transfer efficiency is still very low. To address this issue, we first evaluated the effects of time from cell fusion to activation (<1h, n = 1261; 1-2h, n = 1773; 2-3h, n = 1647) on in vitro and in vivo development of equine embryos generated by cloning. Then, we evaluated the effects of using different nuclear donor cell types in two successive experiments: I) induced pluripotent stem cells (iPSCs) vs. adult fibroblasts (AF) fused to ooplasts injected with the pluripotency-inducing genes OCT4, SOX2, MYC and KLF4, vs. AF alone as controls; II) umbilical cord-derived mesenchymal stromal cells (UC-MSCs) vs. fetal fibroblasts derived from an unborn cloned foetus (FF) vs. AF from the original individual. In the first experiment, both blastocyst production and pregnancy rates were higher in the 2-3h group (11.5% and 9.5%, respectively), respect to <1h (5.2% and 2%, respectively) and 1-2h (5.6% and 4.7%, respectively) groups (P<0.05). However, percentages of born foals/pregnancies were similar when intervals of 2-3h (35.2%) or 1-2h (35.7%) were used. In contrast to AF, the iPSCs did not generate any blastocyst-stage embryos. Moreover, injection of oocytes with the pluripotency-inducing genes did not improve blastocyst production nor pregnancy rates respect to AF controls. Finally, higher blastocyst production was obtained using UC-MSC (15.6%) than using FF (8.9%) or AF (9.3%), (P<0.05). Despite pregnancy rates were similar for these 3 groups (17.6%, 18.2% and 22%, respectively), viable foals (two) were obtained only by using FF. In summary, optimum blastocyst production rates can be obtained using a 2-3h interval between cell fusion and activation as well as using UC-MSCs as nuclear donors. Moreover, FF line can improve the efficiency of an inefficient AF line. Overall, 24 healthy foals were obtained from a total of 29 born foals. PMID:27732616

  19. In Vitro and In Vivo Development of Horse Cloned Embryos Generated with iPSCs, Mesenchymal Stromal Cells and Fetal or Adult Fibroblasts as Nuclear Donors.

    PubMed

    Olivera, Ramiro; Moro, Lucia Natalia; Jordan, Roberto; Luzzani, Carlos; Miriuka, Santiago; Radrizzani, Martin; Donadeu, F Xavier; Vichera, Gabriel

    2016-01-01

    The demand for equine cloning as a tool to preserve high genetic value is growing worldwide; however, nuclear transfer efficiency is still very low. To address this issue, we first evaluated the effects of time from cell fusion to activation (<1h, n = 1261; 1-2h, n = 1773; 2-3h, n = 1647) on in vitro and in vivo development of equine embryos generated by cloning. Then, we evaluated the effects of using different nuclear donor cell types in two successive experiments: I) induced pluripotent stem cells (iPSCs) vs. adult fibroblasts (AF) fused to ooplasts injected with the pluripotency-inducing genes OCT4, SOX2, MYC and KLF4, vs. AF alone as controls; II) umbilical cord-derived mesenchymal stromal cells (UC-MSCs) vs. fetal fibroblasts derived from an unborn cloned foetus (FF) vs. AF from the original individual. In the first experiment, both blastocyst production and pregnancy rates were higher in the 2-3h group (11.5% and 9.5%, respectively), respect to <1h (5.2% and 2%, respectively) and 1-2h (5.6% and 4.7%, respectively) groups (P<0.05). However, percentages of born foals/pregnancies were similar when intervals of 2-3h (35.2%) or 1-2h (35.7%) were used. In contrast to AF, the iPSCs did not generate any blastocyst-stage embryos. Moreover, injection of oocytes with the pluripotency-inducing genes did not improve blastocyst production nor pregnancy rates respect to AF controls. Finally, higher blastocyst production was obtained using UC-MSC (15.6%) than using FF (8.9%) or AF (9.3%), (P<0.05). Despite pregnancy rates were similar for these 3 groups (17.6%, 18.2% and 22%, respectively), viable foals (two) were obtained only by using FF. In summary, optimum blastocyst production rates can be obtained using a 2-3h interval between cell fusion and activation as well as using UC-MSCs as nuclear donors. Moreover, FF line can improve the efficiency of an inefficient AF line. Overall, 24 healthy foals were obtained from a total of 29 born foals.

  20. National Development Generates National Identities

    PubMed Central

    2016-01-01

    The purpose of the article is to test the relationship between national identities and modernisation. We test the hypotheses that not all forms of identity are equally compatible with modernisation as measured by Human Development Index. The less developed societies are characterised by strong ascribed national identities based on birth, territory and religion, but also by strong voluntarist identities based on civic features selected and/or achieved by an individual. While the former decreases with further modernisation, the latter may either decrease or remain at high levels and coexist with instrumental supranational identifications, typical for the most developed countries. The results, which are also confirmed by multilevel regression models, thus demonstrate that increasing modernisation in terms of development contributes to the shifts from classical, especially ascribed, identities towards instrumental identifications. These findings are particularly relevant in the turbulent times increasingly dominated by the hardly predictable effects of the recent mass migrations. PMID:26841050

  1. Development of an automatic block generation algorithm

    NASA Technical Reports Server (NTRS)

    Eberhardt, Scott; Kim, Byoungsoo

    1995-01-01

    A method for automatic multiblock grid generation is described. The method combines the modified advancing front method as a predictor with an elliptic scheme as a corrector. It advances a collection of cells by one cell height in the outward direction using modified advancing front method, and then corrects newly-obtained cell positions by solving elliptic equations. This predictor-corrector type scheme is repeatedly applied until the field of interest is filled with hexahedral grid cells. Given the configuration surface grid, the scheme produces block layouts as well as grid cells with overall smoothness as its output. The method saves human-time and reduces the burden on the user in generating grids for general 3D configurations. It is used to generate multiblock grids for wings in their high-lift configuration.

  2. Emerging methods to generate artificial germ cells from stem cells.

    PubMed

    Zeng, Fanhui; Huang, Fajun; Guo, Jingjing; Hu, Xingchang; Liu, Changbai; Wang, Hu

    2015-04-01

    Germ cells are responsible for the transmission of genetic and epigenetic information across generations. At present, the number of infertile couples is increasing worldwide; these infertility problems can be traced to environmental pollutions, infectious diseases, cancer, psychological or work-related stress, and other factors, such as lifestyle and genetics. Notably, lack of germ cells and germ cell loss present real obstacles in infertility treatment. Recent research aimed at producing gametes through artificial germ cell generation from stem cells may offer great hope for affected couples to treat infertility in the future. Therefore, this rapidly emerging area of artificial germ cell generation from nongermline cells has gained considerable attention from basic and clinical research in the fields of stem cell biology, developmental biology, and reproductive biology. Here, we review the state of the art in artificial germ cell generation. © 2015 by the Society for the Study of Reproduction, Inc.

  3. Fuel cell with storable gas generator

    SciTech Connect

    Iwanciow, B.L.

    1986-12-09

    A system is described for providing gaseous hydrogen and oxygen to a hydrogen/oxygen fuel cell, the combination which comprises: (a) hydrogen/oxygen fuel cell assembly; (b) a hydrogen gas generator having a first heterogeneous mixture comprising lithium borohydride and iron oxide contained therein; (c) a means to initiate the first mixture to generate gaseous hydrogen; (d) a means to feed the gaseous hydrogen to the hydrogen/oxygen fuel cell; (e) an oxygen gas generator having a second heterogeneous mixture comprising sodium chlorate and elemental iron contained therein; (f) a means to initiate the second mixture to generate gaseous oxygen; and (g) a means to feed the gaseous oxygen to the hydrogen/oxygen fuel cell.

  4. Spontaneous generation of germline characteristics in mouse fibrosarcoma cells

    NASA Astrophysics Data System (ADS)

    Ma, Zhan; Hu, Yao; Jiang, Guoying; Hou, Jun; Liu, Ruilai; Lu, Yuan; Liu, Chunfang

    2012-10-01

    Germline/embryonic-specific genes have been found to be activated in somatic tumors. In this study, we further showed that cells functioning as germline could be present in mouse fibrosarcoma cells (L929 cell line). Early germline-like cells spontaneously appeared in L929 cells and further differentiated into oocyte-like cells. These germline-like cells can, in turn, develop into blastocyst-like structures in vitro and cause teratocarcinomas in vivo, which is consistent with natural germ cells in function. Generation of germline-like cells from somatic tumors might provide a novel way to understand why somatic cancer cells have strong features of embryonic/germline development. It is thought that the germline traits of tumors are associated with the central characteristics of malignancy, such as immortalization, invasion, migration and immune evasion. Therefore, germline-like cells in tumors might provide potential targets to tumor biology, diagnosis and therapy.

  5. Spontaneous generation of germline characteristics in mouse fibrosarcoma cells.

    PubMed

    Ma, Zhan; Hu, Yao; Jiang, Guoying; Hou, Jun; Liu, Ruilai; Lu, Yuan; Liu, Chunfang

    2012-01-01

    Germline/embryonic-specific genes have been found to be activated in somatic tumors. In this study, we further showed that cells functioning as germline could be present in mouse fibrosarcoma cells (L929 cell line). Early germline-like cells spontaneously appeared in L929 cells and further differentiated into oocyte-like cells. These germline-like cells can, in turn, develop into blastocyst-like structures in vitro and cause teratocarcinomas in vivo, which is consistent with natural germ cells in function. Generation of germline-like cells from somatic tumors might provide a novel way to understand why somatic cancer cells have strong features of embryonic/germline development. It is thought that the germline traits of tumors are associated with the central characteristics of malignancy, such as immortalization, invasion, migration and immune evasion. Therefore, germline-like cells in tumors might provide potential targets to tumor biology, diagnosis and therapy.

  6. Fuel cell co-generation: the future of co-generation

    NASA Astrophysics Data System (ADS)

    van der Does, Ton

    This paper presents the position of co-generation in a number of countries in the European Union and in more detail the situation in The Netherlands where, at this moment, about more than 30% of the electricity production is based on co-generation. The principal obstacles for the future development of co-generation has been presented. Based on the development of co-generation, which is the most economic and the most efficient way of producing electricity with the advantages for energy conservation and the environment, the fuel cell can play an important role in the change to a more decentralized power production. A future development with a household fuel cell, as an ultimate consequence for decentralized power production, has been presented as a challenge for the actors in the energy market. Based on the Dutch experience, the requirements and critical success factors for fuel cells in a household application have been discussed.

  7. Efficient generation of canine bone marrow-derived dendritic cells.

    PubMed

    Isotani, Mayu; Katsuma, Kensuke; Tamura, Kyoichi; Yamada, Misato; Yagihara, Hiroko; Azakami, Daigo; Ono, Kenichiro; Washizu, Tsukimi; Bonkobara, Makoto

    2006-08-01

    Because of their unsurpassed potency in presenting antigens to naive T cells, dendritic cells are considered to be an important candidate in the development of immunotherapeutic strategies. Despite the high potential of dendritic cell-based immunotherapy, as a so-called dendritic cell vaccination, few clinical approaches using dendritic cell vaccination have been performed in the dog because of very limited information regarding the generation of canine dendritic cells and their functional properties. We therefore established a protocol for the efficient generation of dendritic cells from canine bone marrow cells using recombinant feline granulocyte-macrophage colony-stimulating factor and canine interleukin-4. Dendritic cells were generated efficiently: a yield of 1-9 x 10(6) cells per approximately 0.5 ml of canine bone marrow aspiration was achieved. These dendritic cells showed features shared with mouse and human dendritic cells: dendrite morphology, expression of surface markers MHC class II and CD11c, and up-regulation of molecules related to antigen presentation (MHC class II, B7-1, and B7-2) by activation with lipopolysaccharide. Moreover, the dendritic cells demonstrated phagocytic activity, processing activity of pinocytosed proteins, and activation of allogeneic T cells far more potent than that by macrophages. Our findings suggest that the bone marrow-derived dendritic cells are functional for the capturing and processing of antigens and the initiation of T cell responses.

  8. Developments of terahertz wave generation technologies

    NASA Astrophysics Data System (ADS)

    Suto, Ken; Nishizawa, Jun-Ichi

    2004-05-01

    Recent developments of terahertz wave generation devices utilizing lattice and molecular vibration are introduced. They are semiconductor Raman laser and amplifier, parametric generation of terahertz wave using phonon-polaritons in semiconductors and dielectrics, together with electronic devices: TUNNETT diode and ISIT. Future important applications will be in the field of medicine, biology, and pharmacy.

  9. Reforming of fuel inside fuel cell generator

    DOEpatents

    Grimble, Ralph E.

    1988-01-01

    Disclosed is an improved method of reforming a gaseous reformable fuel within a solid oxide fuel cell generator, wherein the solid oxide fuel cell generator has a plurality of individual fuel cells in a refractory container, the fuel cells generating a partially spent fuel stream and a partially spent oxidant stream. The partially spent fuel stream is divided into two streams, spent fuel stream I and spent fuel stream II. Spent fuel stream I is burned with the partially spent oxidant stream inside the refractory container to produce an exhaust stream. The exhaust stream is divided into two streams, exhaust stream I and exhaust stream II, and exhaust stream I is vented. Exhaust stream II is mixed with spent fuel stream II to form a recycle stream. The recycle stream is mixed with the gaseous reformable fuel within the refractory container to form a fuel stream which is supplied to the fuel cells. Also disclosed is an improved apparatus which permits the reforming of a reformable gaseous fuel within such a solid oxide fuel cell generator. The apparatus comprises a mixing chamber within the refractory container, means for diverting a portion of the partially spent fuel stream to the mixing chamber, means for diverting a portion of exhaust gas to the mixing chamber where it is mixed with the portion of the partially spent fuel stream to form a recycle stream, means for injecting the reformable gaseous fuel into the recycle stream, and means for circulating the recycle stream back to the fuel cells.

  10. Reforming of fuel inside fuel cell generator

    DOEpatents

    Grimble, R.E.

    1988-03-08

    Disclosed is an improved method of reforming a gaseous reformable fuel within a solid oxide fuel cell generator, wherein the solid oxide fuel cell generator has a plurality of individual fuel cells in a refractory container, the fuel cells generating a partially spent fuel stream and a partially spent oxidant stream. The partially spent fuel stream is divided into two streams, spent fuel stream 1 and spent fuel stream 2. Spent fuel stream 1 is burned with the partially spent oxidant stream inside the refractory container to produce an exhaust stream. The exhaust stream is divided into two streams, exhaust stream 1 and exhaust stream 2, and exhaust stream 1 is vented. Exhaust stream 2 is mixed with spent fuel stream 2 to form a recycle stream. The recycle stream is mixed with the gaseous reformable fuel within the refractory container to form a fuel stream which is supplied to the fuel cells. Also disclosed is an improved apparatus which permits the reforming of a reformable gaseous fuel within such a solid oxide fuel cell generator. The apparatus comprises a mixing chamber within the refractory container, means for diverting a portion of the partially spent fuel stream to the mixing chamber, means for diverting a portion of exhaust gas to the mixing chamber where it is mixed with the portion of the partially spent fuel stream to form a recycle stream, means for injecting the reformable gaseous fuel into the recycle stream, and means for circulating the recycle stream back to the fuel cells. 1 fig.

  11. Harnessing Dendritic Cells to Generate Cancer Vaccines

    PubMed Central

    Palucka, Karolina; Ueno, Hideki; Fay, Joseph; Banchereau, Jacques

    2009-01-01

    Passive immunotherapy of cancer, i.e., transfer of T cells or antibodies, can lead to some objective clinical responses, thus demonstrating that the immune system can reject tumors. However, passive immunotherapy is not expected to yield memory T cells that might control tumor outgrowth. Active immunotherapy with dendritic cell (DCs) vaccines has the potential to induce tumor-specific effector and memory T cells. Clinical trials testing first generation DC vaccines pulsed with tumor antigens provided a proof-of-principle that therapeutic immunity can be elicited. Newer generation DC vaccines are build on the increased knowledge of the DC system including the existence of distinct DC subsets and their plasticity all leading to generation of distinct types of immunity. Rather than the quantity of IFN-γ secreting CD8+ T cells, we should aim at generating high quality high avidity poly-functional effector CD8+ T cells able to reject tumors and long-lived memory CD8+ T cells able to prevent relapse. PMID:19769741

  12. Development of 70 MW class superconducting generators

    SciTech Connect

    Ohara, T. ); Fukuda, H. ); Ogawa, T.; Shimizu, K.; Shiobara, R. ); Ohi, M. ); Veda, A. ); Itoh, K. ); Taniguchi, H. )

    1991-03-01

    The application of superconductivity technology to electric power apparatuses is very important from the viewpoint of promotion of energy saving and resource saving. Especially the superconducting generators using superconductors as the field windings have many merits compared with conventional generators. Super-GM has been researching and developing 70 MW class model machines since FY 1988 for a scheduled period of eight years, aiming at a 200 MW class superconducting generator. This paper describes the basic designs and the recent R and D situation of 70 MW superconducting generators by Super-GM.

  13. T cell activation requires force generation

    PubMed Central

    Hu, Kenneth H.

    2016-01-01

    Triggering of the T cell receptor (TCR) integrates both binding kinetics and mechanical forces. To understand the contribution of the T cell cytoskeleton to these forces, we triggered T cells using a novel application of atomic force microscopy (AFM). We presented antigenic stimulation using the AFM cantilever while simultaneously imaging with optical microscopy and measuring forces on the cantilever. T cells respond forcefully to antigen after calcium flux. All forces and calcium responses were abrogated upon treatment with an F-actin inhibitor. When we emulated the forces of the T cell using the AFM cantilever, even these actin-inhibited T cells became activated. Purely mechanical stimulation was not sufficient; the exogenous forces had to couple through the TCR. These studies suggest a mechanical–chemical feedback loop in which TCR-triggered T cells generate forceful contacts with antigen-presenting cells to improve access to antigen. PMID:27241914

  14. Hypoxic culture conditions enhance the generation of regulatory T cells

    PubMed Central

    Neildez-Nguyen, Thi My Anh; Bigot, Jérémy; Da Rocha, Sylvie; Corre, Guillaume; Boisgerault, Florence; Paldi, Andràs; Galy, Anne

    2015-01-01

    The generation of large amounts of induced CD4+ CD25+ Foxp3+ regulatory T (iTreg) cells is of great interest for several immunotherapy applications, therefore a better understanding of signals controlling iTreg cell differentiation and expansion is required. There is evidence that oxidative metabolism may regulate several key signalling pathways in T cells. This prompted us to investigate the effects of oxygenation on iTreg cell generation by comparing the effects of atmospheric (21%) or of low (5%) O2 concentrations on the phenotype of bead-stimulated murine splenic CD4+ T cells from Foxp3-KI-GFP T-cell receptor transgenic mice. The production of intracellular reactive oxygen species was shown to play a major role in the generation of iTreg cells, a process characterized by increased levels of Sirt1, PTEN and Glut1 on the committed cells, independently of the level of oxygenation. The suppressive function of iTreg cells generated either in atmospheric or low oxygen levels was equivalent. However, greater yields of iTreg cells were obtained under low oxygenation, resulting from a higher proliferative rate of the committed Treg cells and higher levels of Foxp3, suggesting a better stability of the differentiation process. Higher expression of Glut1 detected on iTreg cells generated under hypoxic culture conditions provides a likely explanation for the enhanced proliferation of these cells as compared to those cultured under ambient oxygen. Such results have important implications for understanding Treg cell homeostasis and developing in vitro protocols for the generation of Treg cells from naive T lymphocytes. PMID:25243909

  15. Development and characterization of anti-glycopeptide monoclonal antibodies against human podoplanin, using glycan-deficient cell lines generated by CRISPR/Cas9 and TALEN.

    PubMed

    Kaneko, Mika K; Nakamura, Takuro; Honma, Ryusuke; Ogasawara, Satoshi; Fujii, Yuki; Abe, Shinji; Takagi, Michiaki; Harada, Hiroyuki; Suzuki, Hiroyoshi; Nishioka, Yasuhiko; Kato, Yukinari

    2017-02-01

    Human podoplanin (hPDPN), which binds to C-type lectin-like receptor-2 (CLEC-2), is involved in platelet aggregation and cancer metastasis. The expression of hPDPN in cancer cells or cancer-associated fibroblasts indicates poor prognosis. Human lymphatic endothelial cells, lung-type I alveolar cells, and renal glomerular epithelial cells express hPDPN. Although numerous monoclonal antibodies (mAbs) against hPDPN are available, they recognize peptide epitopes of hPDPN. Here, we generated a novel anti-hPDPN mAb, LpMab-21. To characterize the hPDPN epitope recognized by the LpMab-21, we established glycan-deficient CHO-S and HEK-293T cell lines, using the CRISPR/Cas9 or TALEN. Flow cytometric analysis revealed that the minimum hPDPN epitope, in which sialic acid is linked to Thr76, recognized by LpMab-21 is Thr76-Arg79. LpMab-21 detected hPDPN expression in glioblastoma, oral squamous carcinoma, and seminoma cells as well as in normal lymphatic endothelial cells. However, LpMab-21 did not react with renal glomerular epithelial cells or lung type I alveolar cells, indicating that sialylation of hPDPN Thr76 is cell-type-specific. LpMab-21 combined with other anti-hPDPN antibodies that recognize different epitopes may therefore be useful for determining the physiological function of sialylated hPDPN. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  16. Human natural killer cell development.

    PubMed

    Freud, Aharon G; Caligiuri, Michael A

    2006-12-01

    Our understanding of human natural killer (NK) cell development lags far behind that of human B- or T-cell development. Much of our recent knowledge of this incomplete picture comes from experimental animal models that have aided in identifying fundamental in vivo processes, including those controlling NK cell homeostasis, self-tolerance, and the generation of a diverse NK cell repertoire. However, it has been difficult to fully understand the mechanistic details of NK cell development in humans, primarily because the in vivo cellular intermediates and microenvironments of this developmental pathway have remained elusive. Although there is general consensus that NK cell development occurs primarily within the bone marrow (BM), recent data implicate secondary lymphoid tissues as principal sites of NK cell development in humans. The strongest evidence stems from the observation that the newly described stages of human NK cell development are naturally and selectively enriched within lymph nodes and tonsils compared with blood and BM. In the current review, we provide an overview of these recent findings and discuss these in the context of existing tenets in the field of lymphocyte development.

  17. Compact neutron generator development at LBNL

    SciTech Connect

    Reijonen, J.; English, G.; Firestone, R.; Giquel, F.; King, M.; Leung, K-N.; Sun, M.

    2003-12-31

    A wide variety of applications ranging from medical (BNCT, Boron Neutron Capture Therapy) and basic science (neutron imaging, material studies) to homeland security (explosive detection and nuclear material non-proliferation) are in need of compact, high flux neutron generators. The Plasma and Ion Source Technology Group in the Lawrence Berkeley National Laboratory is developing various neutron generators for these applications. These neutron generators employed either the D-D or the D-T fusion reaction for the neutron production. The deuterium or deuterium-tritium gas mixture is ionized in an RF-driven plasma source. The ions are then accelerated to {approx}100 keV energy using high current, high voltage DC-power supply to a target where the 2.45 MeV (for D-D reaction) or 14 MeV (for the D-T reaction) neutrons are generated. The development of two different types of neutron tubes are being discussed in this presentation, namely compact, pulsed operation neutron generators and cw, high yield neutron generators. These generators are currently operating at D-D neutron yields of 108 n/s and 109 n/s respectively. A facility, incorporating the larger neutron generator, has been constructed for Prompt Gamma Activation Analysis (PGAA) and Neutron Activation Analysis (NAA) measurements.

  18. Fuel cell using a hydrogen generation system

    DOEpatents

    Dentinger, Paul M.; Crowell, Jeffrey A. W.

    2010-10-19

    A system is described for storing and generating hydrogen and, in particular, a system for storing and generating hydrogen for use in an H.sub.2/O.sub.2 fuel cell. The hydrogen storage system uses beta particles from a beta particle emitting material to degrade an organic polymer material to release substantially pure hydrogen. In a preferred embodiment of the invention, beta particles from .sup.63Ni are used to release hydrogen from linear polyethylene.

  19. Generation and Function of Induced Regulatory T Cells

    PubMed Central

    Schmitt, Erica G.; Williams, Calvin B.

    2013-01-01

    CD4+ CD25+ Foxp3+ regulatory T (Treg) cells are essential to the balance between pro- and anti-inflammatory responses. There are two major subsets of Treg cells, “natural” Treg (nTreg) cells that develop in the thymus, and “induced” Treg (iTreg) cells that arise in the periphery from CD4+ Foxp3− conventional T cells and can be generated in vitro. Previous work has established that both subsets are required for immunological tolerance. Additionally, in vitro-derived iTreg cells can reestablish tolerance in situations where Treg cells are decreased or defective. This review will focus on iTreg cells, drawing comparisons to nTreg cells when possible. We discuss the molecular mechanisms of iTreg cell induction, both in vivo and in vitro, review the Foxp3-dependent and -independent transcriptional landscape of iTreg cells, and examine the proposed suppressive mechanisms utilized by each Treg cell subset. We also compare the T cell receptor repertoire of the Treg cell subsets, discuss inflammatory conditions where iTreg cells are generated or have been used for treatment, and address the issue of iTreg cell stability. PMID:23801990

  20. Electricity generation using chocolate industry wastewater and its treatment in activated sludge based microbial fuel cell and analysis of developed microbial community in the anode chamber.

    PubMed

    Patil, Sunil A; Surakasi, Venkata Prasad; Koul, Sandeep; Ijmulwar, Shrikant; Vivek, Amar; Shouche, Y S; Kapadnis, B P

    2009-11-01

    Feasibility of using chocolate industry wastewater as a substrate for electricity generation using activated sludge as a source of microorganisms was investigated in two-chambered microbial fuel cell. The maximum current generated with membrane and salt bridge MFCs was 3.02 and 2.3 A/m(2), respectively, at 100 ohms external resistance, whereas the maximum current generated in glucose powered MFC was 3.1 A/m(2). The use of chocolate industry wastewater in cathode chamber was promising with 4.1 mA current output. Significant reduction in COD, BOD, total solids and total dissolved solids of wastewater by 75%, 65%, 68%, 50%, respectively, indicated effective wastewater treatment in batch experiments. The 16S rDNA analysis of anode biofilm and suspended cells revealed predominance of beta-Proteobacteria clones with 50.6% followed by unclassified bacteria (9.9%), alpha-Proteobacteria (9.1%), other Proteobacteria (9%), Planctomycetes (5.8%), Firmicutes (4.9%), Nitrospora (3.3%), Spirochaetes (3.3%), Bacteroides (2.4%) and gamma-Proteobacteria (0.8%). Diverse bacterial groups represented as members of the anode chamber community.

  1. Vortex Generator Model Developed for Turbomachinery

    NASA Technical Reports Server (NTRS)

    Chima, Rodrick V.

    2002-01-01

    A computational model was developed at the NASA Glenn Research Center to investigate possible uses of vortex generators (VG's) for improving the performance of turbomachinery. A vortex generator is a small, winglike device that generates vortices at its tip. The vortices mix high-speed core flow with low-speed boundary layer flow and, thus, can be used to delay flow separation. VG's also turn the flow near the walls and, thus, can be used to control flow incidence into a turbomachinery blade row or to control secondary flows.

  2. Fourth-generation photovoltaic concentrator system development

    SciTech Connect

    O`Neill, M.J.; McDanal, A.J.

    1995-10-01

    In 1991, under a contract with Sandia for the Concentrator Initiative, the ENTECH team initiated the design and development of a fourth-generation concentrator module. In 1992, Sandia also contracted with ENTECH to develop a new control and drive system for the ENTECH array. This report documents the design and development work performed under both contracts. Manufacturing processes for the new module were developed at the same time under a complementary PVMaT contract with the National Renewable Energy Laboratory. Two 100-kW power plants were deployed in 1995 in Texas using the newly developed fourth-generation concentrator technology, one at the CSW Solar Park near Ft. Davis and one at TUE Energy Park in Dallas. Technology developed under the Sandia contracts has made a successful transition from the laboratory to the production line to the field.

  3. Why do taste cells generate action potentials?

    PubMed Central

    Vandenbeuch, Aurelie; Kinnamon, Sue C

    2009-01-01

    Taste cells regularly generate action potentials, but their functional significance in taste signaling is unclear. A paper in BMC Neuroscience reveals the identity of the voltage-gated Na+ channels underlying action potentials, providing the foundation for insights into their function. PMID:19439032

  4. High Temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

    2004-01-01

    The majority of satellites and near-earth probes developed to date have used photovoltaic arrays for power generation. If future mission to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. In this paper, we derive the optimum bandgap as a function of the operating temperature.

  5. Diagnosis of automotive fuel cell power generators

    NASA Astrophysics Data System (ADS)

    Hissel, D.; Péra, M. C.; Kauffmann, J. M.

    Most of car manufacturers around the world have launched important research programs on the integration of fuel cell (FC) power generators into cars. Despite the first achievements, fuel cell systems are still badly known, particularly when talking about fault diagnosis and predictive maintenance. This paper proposes a first step in this way by introducing a simple but also efficient diagnosis-oriented model of a proton exchange membrane fuel cell (PEMFC). The considered diagnosis model is here a fuzzy one and is tuned thanks to genetic algorithms.

  6. Compact neutron generator developement and applications

    SciTech Connect

    Leung, Ka-Ngo; Reijonen, Jani; Gicquel, Frederic; Hahto, Sami; Lou, Tak-Pui

    2004-01-18

    The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory has been engaging in the development of high yield compact neutron generators for the last ten years. Because neutrons in these generators are formed by using either D-D, T-T or D-T fusion reaction, one can produce either mono-energetic (2.4 MeV or 14 MeV) or white neutrons. All the neutron generators being developed by our group utilize 13.5 MHz RF induction discharge to produce a pure deuterium or a mixture of deuterium-tritium plasma. As a result, ion beams with high current density and almost pure atomic ions can be extracted from the plasma source. The ion beams are accelerated to {approx}100 keV and neutrons are produced when the beams impinge on a titanium target. Neutron generators with different configurations and sizes have been designed and tested at LBNL. Their applications include neutron activation analysis, oil-well logging, boron neutron capture therapy, brachytherapy, cargo and luggage screening. A novel small point neutron source has recently been developed for radiography application. The source size can be 2 mm or less, making it possible to examine objects with sharper images. The performance of these neutron generators will be described in this paper.

  7. New generation of dendritic cell vaccines.

    PubMed

    Radford, Kristen J; Caminschi, Irina

    2013-02-01

    Dendritic cells (DC) play a pivotal role in the induction and regulation of immune responses, including the induction of cytotoxic T lymphocytes (CTL) responses. These are essential for the eradication of cancers and pathogens including HIV and malaria, for which there are currently no effective vaccines. New developments in our understanding of DC biology have identified the key DC subset responsible for CTL induction, which is now an attractive candidate to target for vaccination. These DC are characterized by expression of novel markers Clec9A and XCR1, and a specialized capacity to cross-present antigen (Ag) from tumors and pathogens that do not directly infect DC. New generation DC vaccines that specifically target the cross-presenting DC in vivo have already demonstrated potential in preclinical animal models but the challenge remains to translate these findings into clinically efficacous vaccines in man. This has been greatly facilitated by the recent identification of the equivalent Clec9A(+) XCR1(+) cross-presenting DC in human lymphoid tissues and peripheral tissues that are key sites for vaccination administration. These findings combined with further studies on DC subset biology have important implications for the design of new CTL-mediated vaccines.

  8. A Generational Model for Professional Development.

    ERIC Educational Resources Information Center

    Caverly, David C.; Peterson, Cynthia L.; Mandeville, Thomas F.

    1997-01-01

    Describes a social-constructivist model of professional development arising from a collaboration between Southwest Texas State University's education department and New Braunfels (Texas) Independent School District. Teachers learn technology integration techniques from an instructionally strong "first-generation" of teachers trained at a…

  9. Next Generation Drivetrain Development and Test Program

    SciTech Connect

    Keller, Jonathan; Erdman, Bill; Blodgett, Doug; Halse, Chris; Grider, Dave

    2015-11-03

    This presentation was given at the Wind Energy IQ conference in Bremen, Germany, November 30 through December 2, 2105. It focused on the next-generation drivetrain architecture and drivetrain technology development and testing (including gearbox and inverter software and medium-voltage inverter modules.

  10. Internal and ancestral controls of cell-generation times

    NASA Technical Reports Server (NTRS)

    Kubitschek, H. E.

    1969-01-01

    Lateral and longitudinal correlations between related cells reveal associations between the generation times of cells for an intermediate period /three generations in bacteral cultures/. Generation times of progeny are influenced by nongenetic factors transmitted from their ancestors.

  11. Microbial fuel cell (MFC) for bioelectricity generation from organic wastes.

    PubMed

    Moqsud, M Azizul; Omine, Kiyoshi; Yasufuku, Noriyuki; Hyodo, Masayuki; Nakata, Yukio

    2013-11-01

    Microbial fuel cells (MFCs) have gained a lot of attention recently as a mode of converting organic matter into electricity. In this study, a compost-based microbial fuel cell that generates bioelectricity by biodegradation of organic matter is developed. Grass cuttings, along with leaf mold, rice bran, oil cake (from mustard plants) and chicken droppings (waste from chickens) were used as organic waste. The electric properties of the MFC under anaerobic fermentation condition were investigated along with the influence of different types of membranes, the mixing of fly ash, and different types of electrode materials. It is observed that the maximum voltage was increased by mixing fly ash. Cellophane showed the highest value of voltage (around 350mV). Bamboo charcoal is good for anode material; however carbon fiber is better for the cathode material in terms of optimization of power generated. This developed MFC is a simple cell to generate electricity from organic waste.

  12. EMT in breast cancer stem cell generation.

    PubMed

    Ansieau, Stéphane

    2013-09-10

    The concept of cancer stem cells (CSCs) has been proposed to explain the ability of single disseminated cancer cells to reconstitute tumours with heterogeneity similar to that of the primary tumour they arise from. Although this concept is now commonly accepted, the origin of these CSCs remains a source of debate. First proposed to arise through stem/progenitor cell transformation, CSCs might also or alternatively arise from differentiated cancer cells through epithelial to mesenchymal transition (EMT), an embryonic transdifferentiation process. Using breast carcinomas as a study model, I propose revisiting the role of EMT in generating CSCs and the debate on potential underlying mechanisms and biological significance. Copyright © 2012. Published by Elsevier Ireland Ltd.

  13. Development of W-Ta generator

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This research program was used to further develop the existing W-Ta generator and to evaluate alternative adsorbents, preferably inorganic materials, as supports for the generator. During the first half year, combinations of non-complexing eluents and a variety of adsorbents, both inorganic and organic, were evaluated. Some of these adsorbents were synthetic, such as chelate resins that could be specific for tungsten. In the second half of the year, the stress was mainly on the use of complexing eluents because of the high affinity of hydrous oxides for tantalum, on the synthesis of chelate resins and on the use novel techniques (electrolytic) to solve the tantalum-adsorption problem.

  14. Development of a NASA standard gas generator

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Karp, Harold; Schimmel, Morry L.

    1993-01-01

    The goals of the NASA Standard Gas Generator (NSGG) Program are to create a NASA standard gas generating cartridge, characterize its performance, and make it readily available to users. A cartridge within the same envelope as the NASA Standard Initiator (NSI) has the greatest potential use. This potential use is described in viewgraph form. Our approach for NSGG development and qualification was planned to be conducted in several phases. Test methods were developed to evaluate output performance for a variety of potential applications. A feasibility study using modified NSI's was accomplished. Preliminary and final development will be conducted with a delta qualification to evaluate the effects of manufacturing lots and environments. Feasibility study results, feasibility study conclusions, and future plans are presented.

  15. Development of a nitrogen generation system

    NASA Technical Reports Server (NTRS)

    Heppner, D. B.; Marshall, R. D.; Powell, J. D., III; Schubert, F. H.

    1980-01-01

    An eight-stage nitrogen generation module was developed. The design integrated a hydrazine catalytic dissociator, three ammonia dissociation stages and four palladium/silver hydrogen separator stages. Alternating ammonia dissociation and hydrogen separation stages are used to remove hydrogen and ammonia formed in the dissociation of hydrazine which results in negligible ammonia and hydrogen concentrations in the product nitrogen stream. An engineering breadboard nitrogen supply subsystem was also developed. It was developed as an integratable subsystem for a central spacecraft air revitalization system. The subsystem consists of the hydrazine storage and feed mechanism, the nitrogen generation module, the peripheral mechanical and electrical components required to control and monitor subsystem performance, and the instrumentation required to interface with other subsystems of an air revitalization system. The breadboard nitrogen supply subsystem was integrated and tested with a one-person capacity experimental air revitalization system. The integration, checkout and testing was successfully accomplished.

  16. Fuel cells for distributed power generation

    NASA Astrophysics Data System (ADS)

    Tarman, Paul B.

    Deregulation has caused a major change in power distribution in the USA. Large central power stations are being and will continue to be replaced by smaller, distributed power generation sources of less than 20 kW. Fuel cells, specifically molten carbonate fuel cells (MCFCs), are best suited to serve this need. Small turbines cannot achieve the efficiency or environmental friendliness of MCFCs in this power range. This paper discusses the goals of M-C Power Corporation and the advantages of its IMHEX® MCFC technology. M-C Power's factory, demonstration testing program, and its market-entry power plant are also described, as are its commercialization strategy and schedule.

  17. Generation of enteroendocrine cell diversity in midgut stem cell lineages

    PubMed Central

    Beehler-Evans, Ryan; Micchelli, Craig A.

    2015-01-01

    The endocrine system mediates long-range peptide hormone signaling to broadcast changes in metabolic status to distant target tissues via the circulatory system. In many animals, the diffuse endocrine system of the gut is the largest endocrine tissue, with the full spectrum of endocrine cell subtypes not yet fully characterized. Here, we combine molecular mapping, lineage tracing and genetic analysis in the adult fruit fly to gain new insight into the cellular and molecular mechanisms governing enteroendocrine cell diversity. Neuropeptide hormone distribution was used as a basis to generate a high-resolution cellular map of the diffuse endocrine system. Our studies show that cell diversity is seen at two distinct levels: regional and local. We find that class I and class II enteroendocrine cells can be distinguished locally by combinatorial expression of secreted neuropeptide hormones. Cell lineage tracing studies demonstrate that class I and class II cells arise from a common stem cell lineage and that peptide profiles are a stable feature of enteroendocrine cell identity during homeostasis and following challenge with the enteric pathogen Pseudomonas entomophila. Genetic analysis shows that Notch signaling controls the establishment of class II cells in the lineage, but is insufficient to reprogram extant class I cells into class II enteroendocrine cells. Thus, one mechanism by which secretory cell diversity is achieved in the diffuse endocrine system is through cell-cell signaling interactions within individual adult stem cell lineages. PMID:25670792

  18. A self-regulating hydrogen generator for micro fuel cells

    NASA Astrophysics Data System (ADS)

    Moghaddam, Saeed; Pengwang, Eakkachai; Masel, Richard I.; Shannon, Mark A.

    The ever-increasing power demands and miniaturization of portable electronics, micro-sensors and actuators, and emerging technologies such as cognitive arthropods have created a significant interest in development of micro fuel cells. One of the major challenges in development of hydrogen micro fuel cells is the fabrication and integration of auxiliary systems for generating, regulating, and delivering hydrogen gas to the membrane electrode assembly (MEA). In this paper, we report the development of a hydrogen gas generator with a micro-scale control system that does not consume any power. The hydrogen generator consists of a hydride reactor and a water reservoir, with a regulating valve separating them. The regulating valve consists of a port from the water reservoir and a movable membrane with via holes that permit water to flow from the reservoir to the hydride reactor. Water flows towards the hydride reactor, but stops within the membrane via holes due to capillary forces. Water vapor then diffuses from the via holes into the hydride reactor resulting in generation of hydrogen gas. When the rate of hydrogen consumed by the MEA is lower than the generation rate, gas pressure builds up inside the hydride reactor, deflecting the membrane, closing the water regulator valve, until the pressure drops, whereby the valve reopens. We have integrated the self-regulating micro hydrogen generator to a MEA and successfully conducted fuel cell tests under varying load conditions.

  19. Skin tissue generation by laser cell printing.

    PubMed

    Koch, Lothar; Deiwick, Andrea; Schlie, Sabrina; Michael, Stefanie; Gruene, Martin; Coger, Vincent; Zychlinski, Daniela; Schambach, Axel; Reimers, Kerstin; Vogt, Peter M; Chichkov, Boris

    2012-07-01

    For the aim of ex vivo engineering of functional tissue substitutes, Laser-assisted BioPrinting (LaBP) is under investigation for the arrangement of living cells in predefined patterns. So far three-dimensional (3D) arrangements of single or two-dimensional (2D) patterning of different cell types have been presented. It has been shown that cells are not harmed by the printing procedure. We now demonstrate for the first time the 3D arrangement of vital cells by LaBP as multicellular grafts analogous to native archetype and the formation of tissue by these cells. For this purpose, fibroblasts and keratinocytes embedded in collagen were printed in 3D as a simple example for skin tissue. To study cell functions and tissue formation process in 3D, different characteristics, such as cell localisation and proliferation were investigated. We further analysed the formation of adhering and gap junctions, which are fundamental for tissue morphogenesis and cohesion. In this study, it was demonstrated that LaBP is an outstanding tool for the generation of multicellular 3D constructs mimicking tissue functions. These findings are promising for the realisation of 3D in vitro models and tissue substitutes for many applications in tissue engineering. Copyright © 2012 Wiley Periodicals, Inc.

  20. Generation of avian cells resembling osteoclasts from mononuclear phagocytes

    NASA Technical Reports Server (NTRS)

    Alvarez, J. I.; Teitelbaum, S. L.; Blair, H. C.; Greenfield, E. M.; Athanasou, N. A.; Ross, F. P.

    1991-01-01

    Several lines of indirect evidence suggest that a monocyte family precursor gives rise to the osteoclast, although this hypothesis is controversial. Starting with a uniform population of nonspecific esterase positive, tartrate-sensitive, acid phosphatase-producing, mannose receptor-bearing mononuclear cells, prepared from dispersed marrow of calcium-deprived laying hens by cell density separation and selective cellular adherence, we generated multinucleated cells in vitro. When cultured with devitalized bone, these cells show, by electron microscopy, the characteristic osteoclast morphology in that they are mitochondria-rich, multinucleated, and, most importantly, develop characteristic ruffled membranes at the matrix attachment site. Moreover, as documented by scanning electron microscopy, these cells pit bone slices in a manner identical to freshly isolated osteoclasts. In addition, isoenzymes of acid phosphatase from generated osteoclasts, separated by 7.5% polyacrylamide gel electrophoresis at pH 4, are identical to those of mature osteoclasts in migration pattern and tartrate resistance, although the precursor cells from which the osteoclasts are generated produce an entirely different isoenzyme, which is tartrate-sensitive and migrates less rapidly at pH 4. The fused cells also exhibit a cAMP response to prostaglandin E2. Therefore, osteoclast-like cells can be derived by in vitro culture of a marrow-derived monocyte cell population.

  1. Generation of avian cells resembling osteoclasts from mononuclear phagocytes

    NASA Technical Reports Server (NTRS)

    Alvarez, J. I.; Teitelbaum, S. L.; Blair, H. C.; Greenfield, E. M.; Athanasou, N. A.; Ross, F. P.

    1991-01-01

    Several lines of indirect evidence suggest that a monocyte family precursor gives rise to the osteoclast, although this hypothesis is controversial. Starting with a uniform population of nonspecific esterase positive, tartrate-sensitive, acid phosphatase-producing, mannose receptor-bearing mononuclear cells, prepared from dispersed marrow of calcium-deprived laying hens by cell density separation and selective cellular adherence, we generated multinucleated cells in vitro. When cultured with devitalized bone, these cells show, by electron microscopy, the characteristic osteoclast morphology in that they are mitochondria-rich, multinucleated, and, most importantly, develop characteristic ruffled membranes at the matrix attachment site. Moreover, as documented by scanning electron microscopy, these cells pit bone slices in a manner identical to freshly isolated osteoclasts. In addition, isoenzymes of acid phosphatase from generated osteoclasts, separated by 7.5% polyacrylamide gel electrophoresis at pH 4, are identical to those of mature osteoclasts in migration pattern and tartrate resistance, although the precursor cells from which the osteoclasts are generated produce an entirely different isoenzyme, which is tartrate-sensitive and migrates less rapidly at pH 4. The fused cells also exhibit a cAMP response to prostaglandin E2. Therefore, osteoclast-like cells can be derived by in vitro culture of a marrow-derived monocyte cell population.

  2. PEM fuel cells for transportation and stationary power generation applications

    SciTech Connect

    Cleghorn, S.J.; Ren, X.; Springer, T.E.; Wilson, M.S.; Zawodzinski, C.; Zawodzinski, T.A. Jr.; Gottesfeld, S.

    1996-05-01

    We describe recent activities at LANL devoted to polymer electrolyte fuel cells in the contexts of stationary power generation and transportation applications. A low cost/high performance hydrogen or reformate/air stack technology is being developed based on ultralow Pt loadings and on non-machined, inexpensive elements for flow-fields and bipolar plates. On board methanol reforming is compared to the option of direct methanol fuel cells because of recent significant power density increases demonstrated in the latter.

  3. Generating Rho-0 Cells Using Mesenchymal Stem Cell Lines

    PubMed Central

    Fernández-Moreno, Mercedes; Hermida-Gómez, Tamara; Gallardo, M. Esther; Dalmao-Fernández, Andrea; Rego-Pérez, Ignacio; Garesse, Rafael

    2016-01-01

    Introduction The generation of Rho-0 cells requires the use of an immortalization process, or tumor cell selection, followed by culture in the presence of ethidium bromide (EtBr), incurring the drawbacks its use entails. The purpose of this work was to generate Rho-0 cells using human mesenchymal stem cells (hMSCs) with reagents having the ability to remove mitochondrial DNA (mtDNA) more safely than by using EtBr. Methodology Two immortalized hMSC lines (3a6 and KP) were used; 143B.TK-Rho-0 cells were used as reference control. For generation of Rho-0 hMSCs, cells were cultured in medium supplemented with each tested reagent. Total DNA was isolated and mtDNA content was measured by real-time polymerase chain reaction (PCR). Phenotypic characterization and gene expression assays were performed to determine whether 3a6 Rho-0 hMSCs maintain the same stem properties as untreated 3a6 hMSCs. To evaluate whether 3a6 Rho-0 hMSCs had a phenotype similar to that of 143B.TK-Rho-0 cells, in terms of reactive oxygen species (ROS) production, apoptotic levels and mitochondrial membrane potential (Δψm) were measured by flow cytometry and mitochondrial respiration was evaluated using a SeaHorse XFp Extracellular Flux Analyzer. The differentiation capacity of 3a6 and 3a6 Rho-0 hMSCs was evaluated using real-time PCR, comparing the relative expression of genes involved in osteogenesis, adipogenesis and chondrogenesis. Results The results showed the capacity of the 3a6 cell line to deplete its mtDNA and to survive in culture with uridine. Of all tested drugs, Stavudine (dt4) was the most effective in producing 3a6-Rho cells. The data indicate that hMSC Rho-0 cells continue to express the characteristic MSC cell surface receptor pattern. Phenotypic characterization showed that 3a6 Rho-0 cells resembled 143B.TK-Rho-0 cells, indicating that hMSC Rho-0 cells are Rho-0 cells. While the adipogenic capability was higher in 3a6 Rho-0 cells than in 3a6 cells, the osteogenic and chondrogenic

  4. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh

    2004-07-04

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the January to June 2004 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. Also, another activity included in this program focuses on the development of SOFC scale up strategies.

  5. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Faress Rahman; Nguyen Minh

    2004-01-04

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the July 2003 to December 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. Also, another activity included in this program focuses on the development of SOFC scale up strategies.

  6. Adult Limbal Neurosphere Cells: A Potential Autologous Cell Resource for Retinal Cell Generation

    PubMed Central

    Chen, Xiaoli; Thomson, Heather; Cooke, Jessica; Scott, Jennifer; Hossain, Parwez; Lotery, Andrew

    2014-01-01

    The Corneal limbus is a readily accessible region at the front of the eye, separating the cornea and sclera. Neural colonies (neurospheres) can be generated from adult corneal limbus in vitro. We have previously shown that these neurospheres originate from neural crest stem/progenitor cells and that they can differentiate into functional neurons in vitro. The aim of this study was to investigate whether mouse and human limbal neurosphere cells (LNS) could differentiate towards a retinal lineage both in vivo and in vitro following exposure to a developing retinal microenvironment. In this article we show that LNS can be generated from adult mice and aged humans (up to 97 years) using a serum free culture assay. Following culture with developing mouse retinal cells, we detected retinal progenitor cell markers, mature retinal/neuronal markers and sensory cilia in the majority of mouse LNS experiments. After transplantation into the sub-retinal space of neonatal mice, mouse LNS cells expressed photoreceptor specific markers, but no incorporation into host retinal tissue was seen. Human LNS cells also expressed retinal progenitor markers at the transcription level but mature retinal markers were not observed in vitro or in vivo. This data highlights that mouse corneal limbal stromal progenitor cells can transdifferentiate towards a retinal lineage. Complete differentiation is likely to require more comprehensive regulation; however, the accessibility and plasticity of LNS makes them an attractive cell resource for future study and ultimately therapeutic application. PMID:25271851

  7. Quantitative methods for analyzing cell-cell adhesion in development.

    PubMed

    Kashef, Jubin; Franz, Clemens M

    2015-05-01

    During development cell-cell adhesion is not only crucial to maintain tissue morphogenesis and homeostasis, it also activates signalling pathways important for the regulation of different cellular processes including cell survival, gene expression, collective cell migration and differentiation. Importantly, gene mutations of adhesion receptors can cause developmental disorders and different diseases. Quantitative methods to measure cell adhesion are therefore necessary to understand how cells regulate cell-cell adhesion during development and how aberrations in cell-cell adhesion contribute to disease. Different in vitro adhesion assays have been developed in the past, but not all of them are suitable to study developmentally-related cell-cell adhesion processes, which usually requires working with low numbers of primary cells. In this review, we provide an overview of different in vitro techniques to study cell-cell adhesion during development, including a semi-quantitative cell flipping assay, and quantitative single-cell methods based on atomic force microscopy (AFM)-based single-cell force spectroscopy (SCFS) or dual micropipette aspiration (DPA). Furthermore, we review applications of Förster resonance energy transfer (FRET)-based molecular tension sensors to visualize intracellular mechanical forces acting on cell adhesion sites. Finally, we describe a recently introduced method to quantitate cell-generated forces directly in living tissues based on the deformation of oil microdroplets functionalized with adhesion receptor ligands. Together, these techniques provide a comprehensive toolbox to characterize different cell-cell adhesion phenomena during development. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Generation of cell lines for monoclonal antibody production.

    PubMed

    Alvin, Krista; Ye, Jianxin

    2014-01-01

    Monoclonal antibodies (mAbs) represent the largest group of therapeutic proteins with 30 products approved in the USA and hundreds of therapies currently undergoing clinical trials. The complex nature of mAbs makes their development as therapeutic agents constrained by numerous criteria such as quality, safety, regulation, and quantity. Identification of a clonal cell line expressing high levels of mAb with adequate quality attributes and generated in compliance with regulatory standards is a necessary step prior to a program moving to large-scale production for clinical material. This chapter outlines the stable transfection technology that generates clonal cell lines for commercial manufacturing processes.

  9. Circulation control lift generation experiment: Hardware development

    NASA Technical Reports Server (NTRS)

    Panontin, T. L.

    1985-01-01

    A circulation control airfoil and its accompanying hardware were developed to allow the investigation of lift generation that is independent of airfoil angle of attack and relative flow velocity. The test equipment, designed for use in a water tunnel, includes the blown airfoil, the support systems for both flow visualization and airfoil load measurement, and the fluid control system, which utilizes hydraulic technology. The primary design tasks, the selected solutions, and the unforseen problems involved in the development of these individual components of hardware are described.

  10. Self-Contained Thermoelectric Generator for Cell Phones

    NASA Astrophysics Data System (ADS)

    Anatychuk, L. I.; Mykhailovsky, V. Ya.; Strutynska, L. T.

    2011-05-01

    Results of research and development of a 1 W thermoelectric generator for cell phones are presented. A physical model of the generator with catalytic combustion of gas fuel is proposed. A computer simulation method is used to determine the optimal parameters of the thermopile, catalytic heat source, and microgenerator heat rejection system whereby the efficiency of gas combustion heat conversion into electrical energy is a factor of two higher compared with existing analogs. The generator design is described, and results of experimental research on its parameters and the charging rate of cell phone batteries with capacity of 900 mA h to 1600 mA h are given. In the self-contained operating mode of various low-power devices, the elaborated thermoelectric generator with a catalytic heat source is an alternative to traditional sources of chemical energy.

  11. Next Generation LOCAD-PTS Cartridge Development

    NASA Technical Reports Server (NTRS)

    Morris, H.; Nutter, D.; Weite, E.; Wells, M.; Maule, J.; Damon, M.; Monaco, L.; Steele, A.; Wainwright, N.

    2008-01-01

    Future astrobiology exploration missions will require rapid, point-of-use techniques for surface science experiments and contamination monitoring. The Lab-On-a-Chip Application Development (LOCAD) team is developing operational instruments that advance spaceflight technologies to molecular-based methods. Currently, LOCAD-Portable Test System (PTS) is quantifying levels of the bacterial molecule endotoxin onboard the Internatioal Space Station. Future research and development will focus on more sensitive molecular techniques that expand the number of compounds detected to include beta-glucan from fungal cell walls.

  12. Cerebellar granule cells are predominantly generated by terminal symmetric divisions of granule cell precursors.

    PubMed

    Nakashima, Kie; Umeshima, Hiroki; Kengaku, Mineko

    2015-06-01

    Neurons in the central nervous system (CNS) are generated by symmetric and asymmetric cell division of neural stem cells and their derivative progenitor cells. Cerebellar granule cells are the most abundant neurons in the CNS, and are generated by intensive cell division of granule cell precursors (GCPs) during postnatal development. Dysregulation of GCP cell cycle is causal for some subtypes of medulloblastoma. However, the details and mechanisms underlying neurogenesis from GCPs are not well understood. Using long-term live-cell imaging of proliferating GCPs transfected with a fluorescent newborn-granule cell marker, we found that GCPs underwent predominantly symmetric divisions, generating two GCPs or two neurons, while asymmetric divisions generating a GCP and a neuron were only occasionally observed, in both dissociated culture and within tissues of isolated cerebellar lobules. We found no significant difference in cell cycle length between proliferative and neurogenic divisions, or any consistent changes in cell cycle length during repeated proliferative division. Unlike neural stem cells in the cerebral cortex and spinal cord, which generate many neurons by repeated asymmetric division, cerebellar GCPs produce neurons predominantly by terminal symmetric division. These results indicate diverse mechanisms of neurogenesis in the mammalian brain. © 2015 Wiley Periodicals, Inc.

  13. Photocurrent generation in nanostructured organic solar cells.

    PubMed

    Yang, Fan; Forrest, Stephen R

    2008-05-01

    Photocurrent generation in nanostructured organic solar cells is simulated using a dynamical Monte Carlo model that includes the generation and transport properties of both excitons and free charges. Incorporating both optical and electrical properties, we study the influence of the heterojunction nanostructure (e.g., planar vs bulk junctions) on donor-acceptor organic solar cell efficiencies based on the archetype materials copper phthalocyanine (CuPc) and C(60). Structures considered are planar and planar-mixed heterojunctions, homogeneous and phase-separated donor-acceptor (DA) mixtures, idealized structures composed of DA pillars, and nanocrystalline DA networks. The thickness dependence of absorption, exciton diffusion, and carrier collection efficiencies is studied for different morphologies, yielding results similar to those experimentally observed. The influences of charge mobility and exciton diffusion length are studied, and optimal device thicknesses are proposed for various structures. Simulations show that, with currently available materials, nanocrystalline network solar cells optimize both exciton diffusion and carrier collection, thus providing for highly efficient solar energy conversion. Estimations of achievable energy conversion efficiencies are made for the various nanostructures based on current simulations used in conjunction with experimentally obtained fill factors and open-circuit voltages for conventional small molecular weight materials combinations.

  14. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    David Deangelis; Rich Depuy; Debashis Dey; Georgia Karvountzi; Nguyen Minh; Max Peter; Faress Rahman; Pavel Sokolov; Deliang Yang

    2004-09-30

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the April to October 2004 reporting period in Task 2.3 (SOFC Scaleup for Hybrid and Fuel Cell Systems) under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL), entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. This study analyzes the performance and economics of power generation systems for central power generation application based on Solid Oxide Fuel Cell (SOFC) technology and fueled by natural gas. The main objective of this task is to develop credible scale up strategies for large solid oxide fuel cell-gas turbine systems. System concepts that integrate a SOFC with a gas turbine were developed and analyzed for plant sizes in excess of 20 MW. A 25 MW plant configuration was selected with projected system efficiency of over 65% and a factory cost of under $400/kW. The plant design is modular and can be scaled to both higher and lower plant power ratings. Technology gaps and required engineering development efforts were identified and evaluated.

  15. Development of a novel protocol for generating flavivirus reporter particles.

    PubMed

    Fernández, Igor Velado; Okamoto, Natsumi; Ito, Aki; Fukuda, Miki; Someya, Azusa; Nishino, Yosii; Sasaki, Nobuya; Maeda, Akihiko

    2014-11-01

    Infection with West Nile virus (WNV), a mosquito-borne flavivirus, is a growing public and animal health concern worldwide. Prevention, diagnosis and treatment strategies for the infection are urgently required. Recently, viral reverse genetic systems have been developed and applied to clinical WNV virology. We developed a protocol for generating reporter virus particles (RVPs) of WNV with the aim of overcoming two major problems associated with conventional protocols, the difficulty in generating RVPs due to the specific skills required for handling RNAs, and the potential for environmental contamination by antibiotic-resistant genes encoded within the genome RNA of the RVPs. By using the proposed protocol, cells were established in which the RVP genome RNA is replicated constitutively and does not encode any antibiotic-resistant genes, and used as the cell supply for RVP genome RNA. Generation of the WNV RVPs requires only the simple transfection of the expression vectors for the viral structural proteins into the cells. Therefore, no RNA handling is required in this protocol. The WNV RVP yield obtained using this protocol was similar that obtained using the conventional protocol. According to these results, the newly developed protocol appears to be a good alternative for the generation of WNV RVPs, particularly for clinical applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Advanced fuel cell development

    NASA Astrophysics Data System (ADS)

    Pierce, R. D.; Baumert, B.; Claar, T. D.; Fousek, R. J.; Huang, H. S.; Kaun, T. D.; Krumpelt, M.; Minh, N.; Mrazek, F. C.; Poeppel, R. B.

    1985-01-01

    Fuel cell research and development activities at Argonne National Laboratory (ANL) during the period January through March 1984 are described. These efforts have been directed principally toward seeking alternative cathode materials to NiO for molten carbonate fuel cells. Based on an investigation of the thermodynamically stable phases formed under cathode conditions, a number of prospective alternative cathode materials have been identified. From the list of candidates, LiFeO2, Li2MnO3, and ZnO were selected for further investigation. During this quarter, they were doped to promote conductivity and tested for solubility and ion migration in the cell environment. An investigation directed to understanding in cell densification of anode materials was initiated. In addition, calculations were made to evaluate the practicality of controlling sulfur accumulation in molten carbonate fuel cells by bleed off of a portion of the anode gas that could be recycled to the cathode. In addition, a model is being developed to predict the performance of solid oxide fuel cells as a function of cell design and operation.

  17. Development of NO Generator for Medical Applications

    NASA Astrophysics Data System (ADS)

    Namihira, Takao; Wang, Douyan; Katsuki, Sunao; Akiyama, Hidenori; Okamoto, Kazufumi

    Since NO was identified as effective in treatments involving endothelium-derived relaxing factor in 1987, inhalation of NO (iNO) has been widely used in the medical treatment of acute respiratory distress syndrome, acute lung injury, high blood pressure, and other related illnesses. Current iNO systems usually include a gas cylinder of N2 with a high concentration of NO. This system has an inherent risk of generating nitric dioxide (NO2) if leaked NO mixes with air. NO2 is thought to be toxic to the lungs. Therefore, a system that does not include storage of NO is very desirable for administering iNO. In this paper, Prototype of On-site NO generator, which includes a discharge reactor, a NO2-NO catalyst, a charcoal and a particle filter, is developed for animal experiments.

  18. The new generation of vehicles: market opportunities for fuel cells

    NASA Astrophysics Data System (ADS)

    Chalk, Steven G.; Patil, Pandit G.; Venkateswaran, S. R.

    The Partnership for a New Generation of Vehicles (PNGV), a historic US Government-auto industry partnership initiated in 1993, is pursuing three specific, interrelated goals, including the development of the next generation of vehicles capable of achieving up to three times the fuel efficiency of today's comparable vehicles. Fuel cells have been identified as one of three primary propulsion system candidates to meet this triple fuel efficiency goal, since they can dramatically increase automotive propulsion efficiency combined with very low to zero emissions. The US Government is working closely with industry and research institutions in pursuing a strategy of aggressive research and development (R&D) to accelerate the commercialization of fuel cell vehicles. The US Department of Energy has a major role in this fuel cell technology development effort. R&D activities are focused on overcoming the major technical, economic, and infrastructure-related hurdles. The high efficiency, very low emissions, and other favorable characteristics of fuel cells (such as fuel flexibility, low noise, and vibration) create significant market opportunities for fuel cells over the entire spectrum of transportation applications. While the focus of near-term markets for fuel cell vehicles will be urban areas having severe air-quality problems, long-term market prospects are encouraging since fuel cell vehicles can compete on an even ground with conventional vehicles in all key aspects, including vehicle range and refueling. This paper will discuss near- and long-term market opportunities for fuel cells in transportation and provide an update on driving regulatory developments in the USA at the federal and state level. The paper also provides an introduction to the PNGV (focusing on the role and prospects for fuel cells) and discusses the status of fuel cell vehicle development projects.

  19. Future development of large superconducting generators

    SciTech Connect

    Singh, S.K.; Mole, C.J.

    1989-03-01

    Large superconducting generators are being developed worldwide. The use of superconductors to reduce the electrical power dissipation in power equipment has been a technological possibility ever since the discovery of superconductivity, even though their use in power equipment remained an impractical dream for a long time. However, scientific and technological progress in superconductivity and cryogenics has brought this dream much closer to reality. Results obtained so far establish the technical feasibility of these machines. Analytical developments have been providing a sound basis for the design of superconducting machines and results of these design studies have shown improvements in power density of up to a factor of 10 higher than the power density for conventional machines. This paper describes the recently completed USA programs, the current foreign and USA programs, and then proposes a USA development program to maintain leadership in the field.

  20. SNAP-8 electrical generating system development program

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The SNAP-8 program has developed the technology base for one class of multikilowatt dynamic space power systems. Electrical power is generated by a turbine-alternator in a mercury Rankine-cycle loop to which heat is transferred and removed by means of sodium-potassium eutectic alloy subsystems. Final system overall criteria include a five-year operating life, restartability, man rating, and deliverable power in the 90 kWe range. The basic technology has been demonstrated by more than 400,000 hours of major component endurance testing and numerous startup and shutdown cycles. A test system, comprised of developed components, delivered up to 35 kWe for a period exceeding 12,000 hours. The SNAP-8 system baseline is considered to have achieved a level of technology suitable for final application development for long-term multikilowatt space missions.

  1. SNAP-8 electrical generating system development program

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The SNAP-8 program has developed the technology base for one class of multikilowatt dynamic space power systems. Electrical power is generated by a turbine-alternator in a mercury Rankine-cycle loop to which heat is transferred and removed by means of sodium-potassium eutectic alloy subsystems. Final system overall criteria include a five-year operating life, restartability, man rating, and deliverable power in the 90 kWe range. The basic technology was demonstrated by more than 400,000 hours of major component endurance testing and numerous startup and shutdown cycles. A test system, comprised of developed components, delivered up to 35 kWe for a period exceeding 12,000 hours. The SNAP-8 system baseline is considered to have achieved a level of technology suitable for final application development for long-term multikilowatt space missions.

  2. Stabilization of apoptotic cells: generation of zombie cells.

    PubMed

    Oropesa-Ávila, M; Andrade-Talavera, Y; Garrido-Maraver, J; Cordero, M D; de la Mata, M; Cotán, D; Paz, M V; Pavón, A D; Alcocer-Gómez, E; de Lavera, I; Lema, R; Zaderenko, A P; Rodríguez-Moreno, A; Sánchez-Alcázar, J A

    2014-08-14

    Apoptosis is characterized by degradation of cell components but plasma membrane remains intact. Apoptotic microtubule network (AMN) is organized during apoptosis forming a cortical structure beneath plasma membrane that maintains plasma membrane integrity. Apoptotic cells are also characterized by high reactive oxygen species (ROS) production that can be potentially harmful for the cell. The aim of this study was to develop a method that allows stabilizing apoptotic cells for diagnostic and therapeutic applications. By using a cocktail composed of taxol (a microtubule stabilizer), Zn(2+) (a caspase inhibitor) and coenzyme Q10 (a lipid antioxidant), we were able to stabilize H460 apoptotic cells in cell cultures for at least 72 h, preventing secondary necrosis. Stabilized apoptotic cells maintain many apoptotic cell characteristics such as the presence of apoptotic microtubules, plasma membrane integrity, low intracellular calcium levels and mitochondrial polarization. Apoptotic cell stabilization may open new avenues in apoptosis detection and therapy.

  3. Stabilization of apoptotic cells: generation of zombie cells

    PubMed Central

    Oropesa-Ávila, M; Andrade-Talavera, Y; Garrido-Maraver, J; Cordero, M D; de la Mata, M; Cotán, D; Paz, M V; Pavón, A D; Alcocer-Gómez, E; de Lavera, I; Lema, R; Zaderenko, A P; Rodríguez-Moreno, A; Sánchez-Alcázar, J A

    2014-01-01

    Apoptosis is characterized by degradation of cell components but plasma membrane remains intact. Apoptotic microtubule network (AMN) is organized during apoptosis forming a cortical structure beneath plasma membrane that maintains plasma membrane integrity. Apoptotic cells are also characterized by high reactive oxygen species (ROS) production that can be potentially harmful for the cell. The aim of this study was to develop a method that allows stabilizing apoptotic cells for diagnostic and therapeutic applications. By using a cocktail composed of taxol (a microtubule stabilizer), Zn2+ (a caspase inhibitor) and coenzyme Q10 (a lipid antioxidant), we were able to stabilize H460 apoptotic cells in cell cultures for at least 72 h, preventing secondary necrosis. Stabilized apoptotic cells maintain many apoptotic cell characteristics such as the presence of apoptotic microtubules, plasma membrane integrity, low intracellular calcium levels and mitochondrial polarization. Apoptotic cell stabilization may open new avenues in apoptosis detection and therapy. PMID:25118929

  4. Stabilization Of Apoptotic Cells: Generation Of Zombie Cells.

    PubMed

    Sánchez Alcázar, José A; Oropesa Ávila, Manuel; Andrade Talavera, Yuniesky; Garrido Maraver, Juan; de Lavera, Isabel; de la Mata, Mario; Cotán, David; Villanueva Paz, Marina; Delgado Pavón, Ana; Alcocer Gómez, Elisabet; Rodríguez Moreno, Antonio

    2015-08-01

    Apoptosis is characterized by degradation of cell components but plasma membrane remains intact. Apoptotic microtubule network (AMN) is organized during apoptosis forming a cortical structure beneath plasma membrane that maintains plasma membrane integrity. Apoptotic cells are also characterized by high reactive oxygen species (ROS) production that can be potentially harmful for the cell. The aim of this study was to develop a method that allows stabilizing apoptotic cells for diagnostic and therapeutic applications. We were able by using a cocktail composed of taxol (a microtubule stabilizer), Zn(2+) (a caspase inhibitor) and coenzyme Q10 (a lipid antioxidant) to stabilize H460 apoptotic cells in cell cultures for at least 72hours preventing secondary necrosis. Stabilized apoptotic cells maintain many apoptotic cells characteristics such as the presence of apoptotic microtubules, plasma membrane integrity, low intracellular calcium levels, plasma membrane potential, PS externalization and ability of being phagocytosed. Stabilized apoptotic cells can be considered as dying cells in which the cellular cortex and plasma membrane are maintained intact or alive. In a metaphorical sense, we can consider them as "living dead" or "zombie cells". Stabilization of apoptotic cells can be used for reliable detection and quantification of apoptosis in cultured cells and may allow a safer administration of apoptotic cells in clinical applications. Furthermore, it opens new avenues in the functional reconstruction of apoptotic cells for longer preservation.

  5. Advanced fuel cell development

    NASA Astrophysics Data System (ADS)

    Ackerman, J. P.; Pierce, R. D.; Fee, D. C.

    1984-02-01

    Research and development activities on both molten carbonate and solid oxide fuel cells is reported. The efforts on development of molten carbonate fuel cells have been directed principally toward seeking alternative cathode materials to NiO. Based on an investigation of the thermodynamically stable phases formed under cathode conditions with a number of transition metal oxides, synthesis of prospective alternative cathode materials and doping of these materials to promote electronic conductivity is under way. The compounds LiFeO2, Li2MnO3, and ZnO have been doped to give suitable conductivity. Solubility data were taken for NiO, CoO, and NiO-CoO in a cathode environment with different carbonate salt compositions. Techniques are for the preparation of thin electrode and electrolyte materials by tape casting, and a creep resistant superstructure for the anode are studied. Development of an advanced, high power density fuel cell is examined. By employing the thin ceramic layer components of existing solid oxide fuel cells in a strong, lightweight structure of small cells, unequaled power per unit mass or volume can be achieved. Advanced electrolyte fabrication, electrolyte sintering and interconnection and electrode fabrication were investigated.

  6. Training the next generation of pluripotent stem cell researchers.

    PubMed

    Schwartz, Philip Hitchins

    2008-07-23

    Human pluripotent stem cells (PSCs) have the unique properties of being able to proliferate indefinitely in their undifferentiated state and of being able to differentiate into any somatic cell type. These cells are thus posited to be extremely useful for furthering our understanding of both normal and abnormal human development, providing a human cell preparation that can be used to screen for new reagents or therapeutic agents, and generating large numbers of differentiated cells that can be used for transplantation purposes. PSCs in culture have a specific morphology and they express characteristic surface antigens and nuclear transcription factors; thus, PSC culture is very specific and requires a core skill set for successful propagation of these unique cells. Specialized PSC training courses have been extremely valuable in seeding the scientific community with researchers that possess this skill set.

  7. Human skin cells support thymus-independent T cell development

    PubMed Central

    Clark, Rachael A.; Yamanaka, Kei-ichi; Bai, Mei; Dowgiert, Rebecca; Kupper, Thomas S.

    2005-01-01

    Thymic tissue has previously been considered a requirement for the generation of a functional and diverse population of human T cells. We report that fibroblasts and keratinocytes from human skin arrayed on a synthetic 3-dimensional matrix support the development of functional human T cells from hematopoietic precursor cells in the absence of thymic tissue. Newly generated T cells contained T cell receptor excision circles, possessed a diverse T cell repertoire, and were functionally mature and tolerant to self MHC, indicating successful completion of positive and negative selection. Skin cell cultures expressed the AIRE, Foxn1, and Hoxa3 transcription factors and a panel of autoantigens. Skin and bone marrow biopsies can thus be used to generate de novo functional and diverse T cell populations for potential therapeutic use in immunosuppressed patients. PMID:16224538

  8. High Efficiency Cell Development

    NASA Technical Reports Server (NTRS)

    Carbajal, B. G.

    1979-01-01

    The specific activity was to improve the tandem junction Cell (TJC) as a high efficiency solar cell. The TJC development was to be consistent with module assembly and should contribute to the overall goals of the Low-Cost Solar Array Project. During 1978, TJC efficiency improved from approximately 11 percent to approximately 16 percent (AMI). Photogenerated current densities in excess of 42 mA/sq cm were observed at AMO. Open circuit voltages as high as 0.615 V were measured at AMO. Fill factor was only 0.68 - 0.75 due to a nonoptimum metal contact design. A device model was conceived in which the solar cell is modelled as a transitor. There are virtually no interconnect or packaging factor systems and the TJC is compatible with all conventional module fabrication systems. A modification of the TJC, the Front Surface Field (FSF) cell, was also explored.

  9. Advanced fuel cell development

    NASA Astrophysics Data System (ADS)

    1984-06-01

    Fuel cell research and development activities at Argonne National Laboratory (ANL) during the period July through September 1983 are discussed. These efforts were directed principally toward seeking alternative cathode materials to NiO for molten carbonate fuel cells. An investigation was made of the thermodynamically stable phases formed under cathode conditions with a number of transition metal oxides. Prospective alternative cathode materials are being synthesized and doped to promote electronic conductivity. Three materials-LiFeO2, Li2MnO3, and ZnO were doped to give suitable conductivity. These materials are being further tested for solubility and ion migration in the cell environment. Techniques are being studied for the preparation of thin electrode and electrolyte materials by tape casting, and a creep-resistant superstructure for the anode is under development.

  10. Generating Cell Targeting Aptamers for Nanotheranostics Using Cell-SELEX

    PubMed Central

    Lyu, Yifan; Chen, Guang; Shangguan, Dihua; Zhang, Liqin; Wan, Shuo; Wu, Yuan; Zhang, Hui; Duan, Lian; Liu, Chao; You, Mingxu; Wang, Jie; Tan, Weihong

    2016-01-01

    Detecting and understanding changes in cell conditions on the molecular level is of great importance for the accurate diagnosis and timely therapy of diseases. Cell-based SELEX (Systematic Evolution of Ligands by EXponential enrichment), a foundational technology used to generate highly-specific, cell-targeting aptamers, has been increasingly employed in studies of molecular medicine, including biomarker discovery and early diagnosis/targeting therapy of cancer. In this review, we begin with a mechanical description of the cell-SELEX process, covering aptamer selection, identification and identification, and aptamer characterization; following this introduction is a comprehensive discussion of the potential for aptamers as targeting moieties in the construction of various nanotheranostics. Challenges and prospects for cell-SELEX and aptamer-based nanotheranostic are also discussed. PMID:27375791

  11. RBP-J (Rbpsuh) is essential to maintain muscle progenitor cells and to generate satellite cells.

    PubMed

    Vasyutina, Elena; Lenhard, Diana C; Wende, Hagen; Erdmann, Bettina; Epstein, Jonathan A; Birchmeier, Carmen

    2007-03-13

    In the developing muscle, a pool of myogenic progenitor cells is formed and maintained. These resident progenitors provide a source of cells for muscle growth in development and generate satellite cells in the perinatal period. By the use of conditional mutagenesis in mice, we demonstrate here that the major mediator of Notch signaling, the transcription factor RBP-J, is essential to maintain this pool of progenitor cells in an undifferentiated state. In the absence of RBP-J, these cells undergo uncontrolled myogenic differentiation, leading to a depletion of the progenitor pool. This results in a lack of muscle growth in development and severe muscle hypotrophy. In addition, satellite cells are not formed late in fetal development in conditional RBP-J mutant mice. We conclude that RBP-J is required in the developing muscle to set aside proliferating progenitors and satellite cells.

  12. Cartesian-cell based grid generation and adaptive mesh refinement

    NASA Technical Reports Server (NTRS)

    Coirier, William J.; Powell, Kenneth G.

    1993-01-01

    Viewgraphs on Cartesian-cell based grid generation and adaptive mesh refinement are presented. Topics covered include: grid generation; cell cutting; data structures; flow solver formulation; adaptive mesh refinement; and viscous flow.

  13. Differential development of CD4 and CD8 cytotoxic T cells (CTL) in PBMC across the leprosy spectrum; IL-6 with IFN-gamma or IL-2 generate CTL in multibacillary patients.

    PubMed

    de la Barrera, S; Finiasz, D M; Fink, S; Valdez, R; Bottasso, O; Balina, L M; Sasiain, M C

    1997-03-01

    In the present study we evaluated the contribution of CD4 and CD8 T cells on the antigen-specific cytotoxic activity induced by whole Mycobacterium leprae in leprosy patients and normal controls (N) as well as the modulation of this activity by some cytokines. Peripheral blood mononuclear cells (PBMC) from N or from leprosy patients were stimulated with antigen in the presence or absence of cytokines for 7 days. M. leprae-stimulated PBMC were depleted of CD4 or CD8 antigen-bearing cells and employed as effector cells in a 4-hr [31Cr]-release assay against autologous M. leprae-pulsed macrophages. Our results demonstrate that both CD4 and CD8 T cells contribute to M. leprae-induced cytotoxic activity, with differences observed in paucibacillary (PB) and multibacillary (MB) patients. CD8-mediated cytotoxic activity is higher than that of CD4 cells in PB patients, while in MB patients CD4 cytotoxicity is predominant. Our data also demonstrate that the generation of CD4 and CD8 cytotoxic T lymphocytes (CTL) can be modulated differentially by interleukin-4 (IL-4), IL-6, gamma interferon (IFN-gamma), or IL-2. Although MB patients developed the lowest CTL response, cytokines such as IL-6 plus IL-2 or IFN-gamma were able to generate both CD4 and CD8 cytotoxic T cells from MB patients. In PB patients, IL-6 plus IFN-gamma displayed the highest stimulation on CD8 effector cells. Thus, an important role may be assigned to IL-6, together with IL-2 or IFN-gamma, in the differentiation of M. leprae-specific CTL effector cells.

  14. Urine excretion strategy for stem cell-generated embryonic kidneys.

    PubMed

    Yokote, Shinya; Matsunari, Hitomi; Iwai, Satomi; Yamanaka, Shuichiro; Uchikura, Ayuko; Fujimoto, Eisuke; Matsumoto, Kei; Nagashima, Hiroshi; Kobayashi, Eiji; Yokoo, Takashi

    2015-10-20

    There have been several recent attempts to generate, de novo, a functional whole kidney from stem cells using the organogenic niche or blastocyst complementation methods. However, none of these attempts succeeded in constructing a urinary excretion pathway for the stem cell-generated embryonic kidney. First, we transplanted metanephroi from cloned pig fetuses into gilts; the metanephroi grew to about 3 cm and produced urine, although hydronephrosis eventually was observed because of the lack of an excretion pathway. Second, we demonstrated the construction of urine excretion pathways in rats. Rat metanephroi or metanephroi with bladders (developed from cloacas) were transplanted into host rats. Histopathologic analysis showed that tubular lumina dilation and interstitial fibrosis were reduced in kidneys developed from cloacal transplants compared with metanephroi transplantation. Then we connected the host animal's ureter to the cloacal-developed bladder, a technique we called the "stepwise peristaltic ureter" (SWPU) system. The application of the SWPU system avoided hydronephrosis and permitted the cloacas to differentiate well, with cloacal urine being excreted persistently through the recipient ureter. Finally, we demonstrated a viable preclinical application of the SWPU system in cloned pigs. The SWPU system also inhibited hydronephrosis in the pig study. To our knowledge, this is the first report showing that the SWPU system may resolve two important problems in the generation of kidneys from stem cells: construction of a urine excretion pathway and continued growth of the newly generated kidney.

  15. Urine excretion strategy for stem cell-generated embryonic kidneys

    PubMed Central

    Yokote, Shinya; Matsunari, Hitomi; Iwai, Satomi; Yamanaka, Shuichiro; Uchikura, Ayuko; Fujimoto, Eisuke; Matsumoto, Kei; Nagashima, Hiroshi; Kobayashi, Eiji; Yokoo, Takashi

    2015-01-01

    There have been several recent attempts to generate, de novo, a functional whole kidney from stem cells using the organogenic niche or blastocyst complementation methods. However, none of these attempts succeeded in constructing a urinary excretion pathway for the stem cell-generated embryonic kidney. First, we transplanted metanephroi from cloned pig fetuses into gilts; the metanephroi grew to about 3 cm and produced urine, although hydronephrosis eventually was observed because of the lack of an excretion pathway. Second, we demonstrated the construction of urine excretion pathways in rats. Rat metanephroi or metanephroi with bladders (developed from cloacas) were transplanted into host rats. Histopathologic analysis showed that tubular lumina dilation and interstitial fibrosis were reduced in kidneys developed from cloacal transplants compared with metanephroi transplantation. Then we connected the host animal’s ureter to the cloacal-developed bladder, a technique we called the “stepwise peristaltic ureter” (SWPU) system. The application of the SWPU system avoided hydronephrosis and permitted the cloacas to differentiate well, with cloacal urine being excreted persistently through the recipient ureter. Finally, we demonstrated a viable preclinical application of the SWPU system in cloned pigs. The SWPU system also inhibited hydronephrosis in the pig study. To our knowledge, this is the first report showing that the SWPU system may resolve two important problems in the generation of kidneys from stem cells: construction of a urine excretion pathway and continued growth of the newly generated kidney. PMID:26392557

  16. Developing the Second Generation CMORPH: A Prototype

    NASA Astrophysics Data System (ADS)

    Xie, Pingping; Joyce, Robert

    2014-05-01

    A prototype system of the second generation CMORPH is being developed at NOAA Climate Prediction Center (CPC) to produce global analyses of 30-min precipitation on a 0.05deg lat/lon grid over the entire globe from pole to pole through integration of information from satellite observations as well as numerical model simulations. The second generation CMORPH is built upon the Kalman Filter based CMORPH algorithm of Joyce and Xie (2011). Inputs to the system include rainfall and snowfall rate retrievals from passive microwave (PMW) measurements aboard all available low earth orbit (LEO) satellites, estimates derived from infrared (IR) observations of geostationary (GEO) as well as LEO platforms, and precipitation simulations from numerical global models. First, precipitation estimation / retrievals from various sources are mapped onto a global grid of 0.05deg lat/lon and calibrated against a common reference field to ensure consistency in their precipitation rate PDF structures. The motion vectors for the precipitating cloud systems are then defined using information from both satellite IR observations and precipitation fields generated by the NCEP Climate Forecast System Reanalysis (CFSR). To this end, motion vectors are first computed from CFSR hourly precipitation fields through cross-correlation analysis of consecutive hourly precipitation fields on the global T382 (~35 km) grid. In a similar manner, separate processing is also performed on satellite IR-based precipitation estimates to derive motion vectors from observations. A blended analysis of precipitating cloud motion vectors is then constructed through the combination of CFSR and satellite-derived vectors with an objective analysis technique. Fine resolution mapped PMW precipitation retrievals are then separately propagated along the motion vectors from their respective observation times to the target analysis time from both forward and backward directions. The CMORPH high resolution precipitation analyses

  17. α-cell role in β-cell generation and regeneration

    PubMed Central

    Habener, Joel F.; Stanojevic, Violeta

    2012-01-01

    This review considers the role of α-cells in β-cell generation and regeneration. We describe recent evidence obtained from lineage-tracing studies showing that α-cells can serve as progenitors of β-cells and present a hypothetical model how injured β-cells might activate α-cells in adult islets to promote β-cell regeneration. β-cells appear to arise by way of their trans-differentiation from undifferentiated α progenitor cells, pro-α-cells, both during embryonic development of the islets and in the adult pancreas in response to β-cell injuries. Plasticity of α-cells is endowed by the expression of the gene encoding proglucagon, a prohormone that can give rise to glucagon and glucagon-like peptides (GLPs). The production of glucagon from proglucagon is characteristic of fully-differentiated α-cells whereas GLP-1 becomes a product of undifferentiated α-cells. GLP-1, a cell growth and survival factor, is proposed to promote the expansion of undifferentiated pro-α-cells during development. β-cells arise from pro-α-cells by a change in the relative amounts of the transcription factors Arx and Pax4, master regulators of the α- and β-cell lineages, respectively. A paracrine/autocrine model is proposed whereby injuries of β-cells in adult islets induce the production and release of factors, such as stromal cell-derived factor-1, that cause the de-differentiation of adjacent α-cells into pro-α-cells. Pro-α-cells produce GLP-1 and its receptor that renders them competent to trans-differentiate into β-cells. The trans-differentiation of pro-α-cells into β-cells provides a potentially exploitable mechanism for the regeneration of β-cells in individuals with type 1 diabetes. PMID:22847495

  18. Concise Review: Kidney Generation with Human Pluripotent Stem Cells.

    PubMed

    Morizane, Ryuji; Miyoshi, Tomoya; Bonventre, Joseph V

    2017-09-04

    Chronic kidney disease (CKD) is a world-wide healthcare problem, resulting in increased cardiovascular mortality and often leading to end-stage kidney disease, where patients require kidney replacement therapies such as hemodialysis or kidney transplantation. Loss of functional nephrons contributes to the progression of CKD, which can be attenuated but not reversed due to inability to generate new nephrons in human adult kidneys. Human pluripotent stem cells (hPSCs), by virtue of their unlimited self-renewal and ability to differentiate into cells of all three embryonic germ layers, are attractive sources for kidney regenerative therapies. Recent advances in stem cell biology have identified key signals necessary to maintain stemness of human nephron progenitor cells (NPCs) in vitro, and led to establishment of protocols to generate NPCs and nephron epithelial cells from human fetal kidneys and hPSCs. Effective production of large amounts of human NPCs and kidney organoids will facilitate elucidation of developmental and pathobiological pathways, kidney disease modeling and drug screening as well as kidney regenerative therapies. We summarize the recent studies to induce NPCs and kidney cells from hPSCs, studies of NPC expansion from mouse and human embryonic kidneys, and discuss possible approaches in vivo to regenerate kidneys with cell therapies and the development of bioengineered kidneys. Stem Cells 2017. © 2017 AlphaMed Press.

  19. Generation of stomach tissue from mouse embryonic stem cells.

    PubMed

    Noguchi, Taka-aki K; Ninomiya, Naoto; Sekine, Mari; Komazaki, Shinji; Wang, Pi-Chao; Asashima, Makoto; Kurisaki, Akira

    2015-08-01

    Successful pluripotent stem cell differentiation methods have been developed for several endoderm-derived cells, including hepatocytes, β-cells and intestinal cells. However, stomach lineage commitment from pluripotent stem cells has remained a challenge, and only antrum specification has been demonstrated. We established a method for stomach differentiation from embryonic stem cells by inducing mesenchymal Barx1, an essential gene for in vivo stomach specification from gut endoderm. Barx1-inducing culture conditions generated stomach primordium-like spheroids, which differentiated into mature stomach tissue cells in both the corpus and antrum by three-dimensional culture. This embryonic stem cell-derived stomach tissue (e-ST) shared a similar gene expression profile with adult stomach, and secreted pepsinogen as well as gastric acid. Furthermore, TGFA overexpression in e-ST caused hypertrophic mucus and gastric anacidity, which mimicked Ménétrier disease in vitro. Thus, in vitro stomach tissue derived from pluripotent stem cells mimics in vivo development and can be used for stomach disease models.

  20. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh; Faress Rahman

    2002-12-31

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the October 2002 to December 2002 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The following activities have been carried out during this reporting period: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} Part-load performance analysis was conducted {lg_bullet} Primary system concept was down-selected {lg_bullet} Dynamic control model has been developed {lg_bullet} Preliminary heat exchanger designs were prepared {lg_bullet} Pressurized SOFC endurance testing was performed

  1. Mesenchymal stem cell like (MSCl) cells generated from human embryonic stem cells support pluripotent cell growth

    SciTech Connect

    Varga, Nora; Vereb, Zoltan; Rajnavoelgyi, Eva; Nemet, Katalin; Uher, Ferenc; Sarkadi, Balazs; Apati, Agota

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer MSC like cells were derived from hESC by a simple and reproducible method. Black-Right-Pointing-Pointer Differentiation and immunosuppressive features of MSCl cells were similar to bmMSC. Black-Right-Pointing-Pointer MSCl cells as feeder cells support the undifferentiated growth of hESC. -- Abstract: Mesenchymal stem cell like (MSCl) cells were generated from human embryonic stem cells (hESC) through embryoid body formation, and isolated by adherence to plastic surface. MSCl cell lines could be propagated without changes in morphological or functional characteristics for more than 15 passages. These cells, as well as their fluorescent protein expressing stable derivatives, efficiently supported the growth of undifferentiated human embryonic stem cells as feeder cells. The MSCl cells did not express the embryonic (Oct4, Nanog, ABCG2, PODXL, or SSEA4), or hematopoietic (CD34, CD45, CD14, CD133, HLA-DR) stem cell markers, while were positive for the characteristic cell surface markers of MSCs (CD44, CD73, CD90, CD105). MSCl cells could be differentiated toward osteogenic, chondrogenic or adipogenic directions and exhibited significant inhibition of mitogen-activated lymphocyte proliferation, and thus presented immunosuppressive features. We suggest that cultured MSCl cells can properly model human MSCs and be applied as efficient feeders in hESC cultures.

  2. SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

    SciTech Connect

    Faress Rahman; Nguyen Minh

    2003-07-01

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the January 2003 to June 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. This report summarizes the results obtained to date on: System performance analysis and model optimization; Reliability and cost model development; System control including dynamic model development; Heat exchanger material tests and life analysis; Pressurized SOFC evaluation; and Pre-baseline system definition for coal gasification fuel cell system concept.

  3. High-temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Merritt, Danielle; Raffaelle, Ryne P.; Scheiman, David

    2005-01-01

    The vast majority of space probes to date have relied upon photovoltaic power generation. If future missions designed to probe environments close to the sun (Figure 1) will be able to use such power generation, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. The significant problem is that solar cells lose performance at high temperatures.

  4. Red blood cells and thrombin generation in sickle cell disease.

    PubMed

    Whelihan, Matthew F; Lim, Ming Y; Key, Nigel S

    2014-05-01

    The prothrombotic nature of sickle cell disease (SCD) is evidenced by the chronically elevated levels of almost all coagulation activation biomarkers, and an increased incidence of certain thrombotic events, including venous thromboembolism. Numerous studies have attempted to define the extent and elucidate the mechanism of the observed increase in thrombin generation in SCD patients in vivo. In general, these studies were performed using thrombin generation assays in platelet poor or platelet rich plasma and showed little difference in endogenous thrombin potential between the SCD cohort and healthy matched controls. In SCD, erythrocytes and monocytes have been demonstrated to exhibit procoagulant characteristics. Thus, the absence of these cellular components in standard thrombin generation assays may fail to reflect global hypercoagulability in the whole blood of patients with SCD. We were therefore surprised to see no difference in net thrombin generation in tissue factor-initiated initiated clotting of whole blood from patients with SCD. However, we are continuing to reconcile these seemingly disparate observations by slight modifications of the whole blood model that include alternative coagulation triggers and a re-examination of the net thrombin generation when the protein/protein S system is simultaneously interrogated.

  5. Mechanochemical models for generating biological pattern and form in development

    NASA Astrophysics Data System (ADS)

    Murray, J. D.; Maini, P. K.; Tranquillo, R. T.

    1988-12-01

    The central issue in development is the formation of spatial patterns of cells in the early embryo. The mechanisms which generate these patterns are unknown. Here we describe the new Oster-Murray mechanochemical approach to the problem, the elements of which are experimentally well documented. By way of illustration we derive one of the basic models from first principles and apply it to a variety of problems of current interest and research. We specifically discuss the formation of skin organ patterns, such as feather and scale germs, cartilage condensations in the developing vertebrate limb and finally wound healing.

  6. U.S. distributed generation fuel cell program

    NASA Astrophysics Data System (ADS)

    Williams, M. C.; Strakey, J. P.; Singhal, Subhash C.

    The Department of Energy (DOE) is the largest funder of fuel cell technology in the U.S. The Department of Energy—Office of Fossil Energy (FE) is developing high temperature fuel cells for distributed generation. It has funded the development of tubular solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) power systems operating at up to 60% efficiency on natural gas. The remarkable environmental performance of these fuel cells makes them likely candidates to help mitigate pollution. DOE is now pursuing more widely applicable solid oxide fuel cells for 2010 and beyond. DOE estimates that a 5 kW solid oxide fuel cell system can reach $400 per kW at reasonable manufacturing volumes. SECA—the Solid State Energy Conversion Alliance—was formed by the National Energy Technology Laboratory (NETL) and the Pacific Northwest National Laboratory (PNNL) to accelerate the commercial readiness of planar and other solid oxide fuel cell systems utilizing 3-10 kW size modules by taking advantage of the projected economies of production from a "mass customization" approach. In addition, if the modular 3-10 kW size units can be "ganged" or "scaled-up" to larger sizes with no increase in cost, then commercial, microgrid, and other distributed generation markets will become attainable. Further scale-up and hybridization of SECA SOFCs with gas turbines could result in penetration of the bulk power market. This paper reviews the current status of the solid oxide and molten carbonate fuel cells in the U.S.

  7. Pancreatic Islet Cell Development and Regeneration

    PubMed Central

    Romer, Anthony I.; Sussel, Lori

    2015-01-01

    Purpose This review will discuss recent advances in understanding mouse and human pancreatic islet cell development, novel concepts related to β cell dysfunction and improved approaches for replenishing β cells to treat diabetes. Recent Findings Considerable knowledge about pancreatic islet development and function has been gained using model systems with subsequent validation in human tissues. Recently, several rodent studies have revealed that differentiated adult islet cells retain remarkable plasticity and can be converted to other islet cell types by perturbing their transcription factor profiles. Furthermore, significant advances have been made in the generation of β-like cells from stem cell populations. Therefore, the generation of functionally mature β cells by the in situ conversion of non-β cell populations or by the directed differentiation of human pluripotent stem cells could represent novel mechanisms for replenishing β cells in diabetic patients. Summary The overall conservation between mouse and human pancreatic development, islet physiology and etiology of diabetes encourages the translation of novel β cell replacement therapies to humans. Further deciphering the molecular mechanisms that direct islet cell regeneration, plasticity and function could improve and expand the β cell replacement strategies for treating diabetes. PMID:26087337

  8. Development of portable fuel cells

    SciTech Connect

    Nakatou, K.; Sumi, S.; Nishizawa, N.

    1996-12-31

    Sanyo Electric has been concentrating on developing a marketable portable fuel cell using phosphoric acid fuel cells (PAFC). Due to the fact that this power source uses PAFC that operate at low temperature around 100{degrees} C, they are easier to handle compared to conventional fuel cells that operate at around 200{degrees} C , they can also be expected to provide extended reliable operation because corrosion of the electrode material and deterioration of the electrode catalyst are almost completely nonexistent. This power source is meant to be used independently and stored at room temperature. When it is started up, it generates electricity itself using its internal load to raise the temperature. As a result, the phosphoric acid (the electolyte) absorbs the reaction water when the temperature starts to be raised (around room temperature). At the same time the concentration and volume of the phosphoric acid changes, which may adversely affect the life time of the cell. We have studied means for starting, operating PAFC stack using methods that can simply evaluate changes in the concentration of the electrolyte in the stack with the aim of improving and extending cell life and report on them in this paper.

  9. Local biofuels power plants with fuel cell generators

    SciTech Connect

    Lindstroem, O.

    1996-12-31

    The fuel cell should be a most important option for Asian countries now building up their electricity networks. The fuel cell is ideal for the schemes for distributed generation which are more reliable and efficient than the centralized schemes so far favoured by the industrialized countries in the West. Not yet developed small combined cycle power plants with advanced radial gas turbines and compact steam turbines will be the competition. Hot combustion is favoured today but cold combustion may win in the long run thanks to its environmental advantages. Emission standards are in general determined by what is feasible with available technology. The simple conclusion is that the fuel cell has to prove that it is competitive to the turbines in cost engineering terms. A second most important requirement is that the fuel cell option has to be superior with respect to electrical efficiency.

  10. Generating Inner Ear Organoids from Mouse Embryonic Stem Cells.

    PubMed

    Longworth-Mills, Emma; Koehler, Karl R; Hashino, Eri

    2016-01-01

    This protocol describes a three-dimensional culture method for generating inner ear sensory epithelia, which comprises sensory hair cells and a concurrently arising neuronal population. Mouse embryonic stem cells are initially plated in 96-well plates with differentiation media; following aggregation, Matrigel is added in order to promote epithelialization. A series of small molecule applications is then used over the first 14 days of culture to guide differentiation towards an otic lineage. After 16-20 days, vesicles containing inner ear sensory hair cells and supporting cells arise from the cultured aggregates. Aggregates may be analyzed using immunohistochemistry and electrophysiology techniques. This system serves as a simple and relatively inexpensive in vitro model of inner ear development.

  11. Development of tungsten-tantalum generator

    NASA Technical Reports Server (NTRS)

    Leblanc, A.; Babich, J.; Jhingran, S. G.

    1985-01-01

    The purpose of this project was to develop a useable tungsten (W)/tantalum (Ta) generator. Ta-178 is formed following the decay of its parent, W-178 (half-life: 21.7d) and has a half life of 9.3 minutes in turn yielding stable Hf-178. The decay of the parent isotope (W-178) occurs entirely by electron capture to the 9.3 minute Ta-178 state, without feeding the high spin Ta-178 isomer (half life 2.2 hours). In Ta-178 decay, 99.2% of the disintegrations proceed by electron capture and 0.18% by positron emission. Electron capture results in a 61.2% branch to the ground state of Hf-178 and 33.7% to the first excited state at 93 1KeV. The most prominent features of the radionuclide's energy spectrum are the hafnium characteristic radiation peaks with energies between 54.6 and 65.0 KeV. The radiation exposure dose of Ta-118 was calculated to be approximately one-twentieth that of Tc-99m on a per millicurie basis. A twenty-fold reduction in radiation exposure from Ta-178 compared with Tc-99m means that the usual administered dose can be increased three or four times, greatly increasing statistical accuracy while reducing radiation exposure by a factor of five.

  12. Developing instrumentation to characterize thermoelectric generator modules

    NASA Astrophysics Data System (ADS)

    Liu, Dawei; Li, Qiming; Peng, Wenbo; Zhu, Lianjun; Gao, Hu; Meng, Qingsen; Jin, A. J.

    2015-03-01

    Based on the law of physics, known as "Seebeck effect," a thermoelectric generator (TEG) produces electricity when the temperature differential is applied across the TEG. This article reports a precision method in characterizing TEG modules. A precision instrument is constructed to study thermoelectric conversion in terms of output power and efficiency of TEG modules. The maximum allowable TEG module size is 150 mm, and the preferred size is from 30 mm to 60 mm. During measurements, the highest hot side temperature is 500 °C and the cold side temperature can be adjusted from room temperature to 100 °C. A mechanical structure is developed to control the pressure and parallelism of the clamping force of the TEG on both its hot and cold sides. A heat flux measurement module is installed at its cold side, and the heat flux through TEGs can be measured in position. Finally, the energy conversion efficiency of TEGs is calculated from experimental data of both an output power and a heat flux.

  13. Next-Generation Ion Propulsion Being Developed

    NASA Technical Reports Server (NTRS)

    Patterson, Michael J.; Soulas, George C.; Foster, John E.; Haag, Thomas W.; Pinero, Luis R.; Rawlin, Vincent K.; Doehne, S. Michelle

    2001-01-01

    The NASA Glenn Research Center ion-propulsion program addresses the need for high specific-impulse systems and technology across a broad range of mission applications and power levels. One activity is the development of the next-generation ion-propulsion system as a follow-on to the successful Deep Space 1 system. The system is envisioned to incorporate a lightweight ion engine that can operate over 1 to 10 kW, with a 550-kg propellant throughput capacity. The engine concept under development has a 40-cm beam diameter, twice the effective area of the Deep Space 1 engine. It incorporates mechanical features and operating conditions to maximize the design heritage established by the Deep Space 1 engine, while incorporating new technology where warranted to extend the power and throughput capability. Prototype versions of the engine have been fabricated and are under test at NASA, with an engineering model version in manufacturing. Preliminary performance data for the prototype engine have been documented over 1.1- to 7.3-kW input power. At 7.3 kW, the engine efficiency is 0.68, at 3615-sec specific impulse. Critical component temperatures, including those of the discharge cathode assembly and magnets, have been documented and are within established limits, with significant margins relative to the Deep Space 1 engine. The 1- to 10-kW ion thruster approach described here was found to provide the needed power and performance improvement to enable important NASA missions. The Integrated In-Space Transportation Planning (IISTP) studies compared many potential technologies for various NASA, Government, and commercial missions. These studies indicated that a high-power ion propulsion system is the most important technology for development because of its outstanding performance versus perceived development and recurring costs for interplanetary solar electric propulsion missions. One of the best applications of a highpower electric propulsion system was as an integral part

  14. AC power generation from microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  15. Generation of mouse chimeras with high contribution of tetraploid embryonic stem cells and embryonic stem cell-fibroblast hybrid cells.

    PubMed

    Matveeva, Natalia M; Kizilova, Elena A; Serov, Oleg L

    2015-01-01

    The in vitro long-term cultivation of embryonic stem (ES) cells derived from pre-implantation embryos offers the unique possibility of combining ES cells with pre-implantation embryos to generate chimeras, thus facilitating the creation of a bridge between in vitro and in vivo investigations. Genomic manipulation using ES cells and homologous recombination is one of the most outstanding scientific achievements, resulting in the generation of animals with desirable genome modifications. As such, the generation of ES cells with different ploidy via cell fusion also deserves much attention because this approach allows for the production of chimeras that contain somatic cells with various ploidy. Therefore, this is a powerful tool that can be used to study the role of polyploidy in the normal development of mammals.

  16. Listeria monocytogenes-Induced Cell Death Inhibits the Generation of Cell-Mediated Immunity

    PubMed Central

    Theisen, Erin

    2016-01-01

    ABSTRACT The influence of cell death on adaptive immunity has been studied for decades. Despite these efforts, the intricacies of how various cell death pathways shape immune responses in the context of infection remain unclear, particularly with regard to more recently discovered pathways such as pyroptosis. The emergence of Listeria monocytogenes as a promising immunotherapeutic platform demands a thorough understanding of how cell death induced in the context of infection influences the generation of CD8+ T-cell-mediated immune responses. To begin to address this question, we designed strains of L. monocytogenes that robustly activate necrosis, apoptosis, or pyroptosis. We hypothesized that proinflammatory cell death such as necrosis would be proimmunogenic while apoptosis would be detrimental, as has previously been reported in the context of sterile cell death. Surprisingly, we found that the activation of any host cell death in the context of L. monocytogenes infection inhibited the generation of protective immunity and specifically the activation of antigen-specific CD8+ T cells. Importantly, the mechanism of attenuation was unique for each type of cell death, ranging from deficits in costimulation in the context of necrosis to a suboptimal inflammatory milieu in the case of pyroptosis. Our results suggest that cell death in the context of infection is different from sterile-environment-induced cell death and that inhibition of cell death or its downstream consequences is necessary for developing effective cell-mediated immune responses using L. monocytogenes-based immunotherapeutic platforms. PMID:27821585

  17. Cell cycle control and seed development

    PubMed Central

    Dante, Ricardo A.; Larkins, Brian A.; Sabelli, Paolo A.

    2014-01-01

    Seed development is a complex process that requires coordinated integration of many genetic, metabolic, and physiological pathways and environmental cues. Different cell cycle types, such as asymmetric cell division, acytokinetic mitosis, mitotic cell division, and endoreduplication, frequently occur in sequential yet overlapping manner during the development of the embryo and the endosperm, seed structures that are both products of double fertilization. Asymmetric cell divisions in the embryo generate polarized daughter cells with different cell fates. While nuclear and cell division cycles play a key role in determining final seed cell numbers, endoreduplication is often associated with processes such as cell enlargement and accumulation of storage metabolites that underlie cell differentiation and growth of the different seed compartments. This review focuses on recent advances in our understanding of different cell cycle mechanisms operating during seed development and their impact on the growth, development, and function of seed tissues. Particularly, the roles of core cell cycle regulators, such as cyclin-dependent-kinases and their inhibitors, the Retinoblastoma-Related/E2F pathway and the proteasome-ubiquitin system, are discussed in the contexts of different cell cycle types that characterize seed development. The contributions of nuclear and cellular proliferative cycles and endoreduplication to cereal endosperm development are also discussed. PMID:25295050

  18. Cell cycle control and seed development.

    PubMed

    Dante, Ricardo A; Larkins, Brian A; Sabelli, Paolo A

    2014-01-01

    Seed development is a complex process that requires coordinated integration of many genetic, metabolic, and physiological pathways and environmental cues. Different cell cycle types, such as asymmetric cell division, acytokinetic mitosis, mitotic cell division, and endoreduplication, frequently occur in sequential yet overlapping manner during the development of the embryo and the endosperm, seed structures that are both products of double fertilization. Asymmetric cell divisions in the embryo generate polarized daughter cells with different cell fates. While nuclear and cell division cycles play a key role in determining final seed cell numbers, endoreduplication is often associated with processes such as cell enlargement and accumulation of storage metabolites that underlie cell differentiation and growth of the different seed compartments. This review focuses on recent advances in our understanding of different cell cycle mechanisms operating during seed development and their impact on the growth, development, and function of seed tissues. Particularly, the roles of core cell cycle regulators, such as cyclin-dependent-kinases and their inhibitors, the Retinoblastoma-Related/E2F pathway and the proteasome-ubiquitin system, are discussed in the contexts of different cell cycle types that characterize seed development. The contributions of nuclear and cellular proliferative cycles and endoreduplication to cereal endosperm development are also discussed.

  19. Generation of induced pluripotent stem cell-derived mice by reprogramming of a mature NKT cell.

    PubMed

    Ren, Yue; Dashtsoodol, Nyambayar; Watarai, Hiroshi; Koseki, Haruhiko; Quan, Chengshi; Taniguchi, Masaru

    2014-10-01

    NKT cells are characterized by their expression of an NKT-cell-specific invariant antigen-receptor α chain encoded by Vα14Jα18 gene segments. These NKT cells bridge the innate and acquired immune systems to mediate effective and augmented responses; however, the limited number of NKT cells in vivo hampers their analysis. Here, two lines of induced pluripotent stem cell-derived mice (NKT-iPSC-derived mice) were generated by reprogramming of mature NKT cells, where one harbors both rearranged Vα14Jα18 and Vβ7 genes and the other carries rearranged Vα14Jα18 on both alleles but germline Vβ loci. The analysis of NKT-iPSC-derived mice showed a significant increase in NKT cell numbers with relatively normal frequencies of functional subsets, but significantly enhanced in some cases, and acquired functional NKT cell maturation in peripheral lymphoid organs. NKT-iPSC-derived mice also showed normal development of other immune cells except for the absence of γδT cells and disturbed development of conventional CD4 αβT cells. These results suggest that the NKT-iPSC-derived mice are a better model for NKT cell development and function study rather than transgenic mouse models reported previously and also that the presence of a pre-rearranged Vα14Jα18 in the natural chromosomal context favors the developmental fate of NKT cells.

  20. 2nd Generation ELT Performance Specification Development

    NASA Technical Reports Server (NTRS)

    Stimson, Chad M.

    2015-01-01

    NASA Search And Rescue is supporting RTCA SC-229 with research and recommendations for performance specifications for the 2nd generation of emergency locator transmitters. Areas for improvement and methods for collecting data will be presented.

  1. EIDA Next Generation: ongoing and future developments

    NASA Astrophysics Data System (ADS)

    Strollo, Angelo; Quinteros, Javier; Sleeman, Reinoud; Trani, Luca; Clinton, John; Stammler, Klaus; Danecek, Peter; Pedersen, Helle; Ionescu, Constantin

    2015-04-01

    The European Integrated Data Archive (EIDA; http://www.orfeus-eu.org/eida/eida.html) is the distributed Data Centre system within ORFEUS, providing transparent access and services to high quality, seismic data across (currently) 9 large data archives in Europe. EIDA is growing, in terms of the number of participating data centres, the size of the archives, the variability of the data in the archives, the number of users, and the volume of downloads. The on-going success of EIDA is thus providing challenges that are the driving force behind the design of the next generation (NG) of EIDA, which is expected to be implemented within EPOS IP. EIDA ORFEUS must cope with further expansion of the system and more complex user requirements by developing new techniques and extended services. The EIDA NG is being designed to work on standard FDSN web services and two additional new web services: Routing Service and QC (quality controlled) service. This presentation highlights the challenges EIDA needs to address during the EPOS IP and focuses on these 2 new services. The Routing Service can be considered as the core of EIDA NG. It was designed to assist users and clients to locate data within a federated, decentralized data centre (e.g. EIDA). A detailed, FDSN-compliant specification of the service has been developed. Our implementation of this service will run at every EIDA node, but is also capable of running on a user's computer, allowing anyone to define virtual or integrate existing data centres. This (meta)service needs to be queried in order to locate the data. Some smart clients (in a beta status) have been also provided to offer the user an integrated view of the whole EIDA, hiding the complexity of its internal structure. The service is open and able to be queried by anyone without the need of credentials or authentication. The QC Service is developed to cope with user requirements to query for relevant data only. The web service provides detailed information on the

  2. Generation of CD4+ blastoid T cells in recipients of BP/IFA-sensitized spleen cells.

    PubMed

    Kira, J; Itoyama, Y; Goto, I

    1990-06-01

    While sensitization of Lewis rats with BP/IFA does not induce EAE, recipients given BP/IFA-sensitized cells after culture with BP do develop EAE. To clarify the pathophysiology responsible for this discrepancy, cell dynamics were studied in the recipients. The CD4+ T cells from BP/IFA-sensitized donors showed no proliferative response to BP and no change in cell size or surface molecule expression, even in the presence of BP in culture. On the other hand, the recipient cells proliferated vigorously, regardless of the presence or absence of BP. In this case, a large number of CD4+ blastoid T cells was generated only in the presence of BP in culture. Such cells showed marked upregulation of CD4, CD2, class I and II MHC, and IL2 receptor molecules, a finding we also observed in the case of BP-cultured cells from BP/CFA-sensitized rats with severe EAE. The proportion of CD4+ blastoid T cells generated after culture depended on the number of cells transferred and on the presence of BP in culture, and closely correlated with the severity of EAE in the recipients. These data suggest that BP/IFA-sensitization can also induce BP-reactive cells capable of becoming CD4+ blastoid T cells with marked upregulation of CD4, CD2, class I and II MHC, and IL2 receptor molecules directly related to potent encephalitogenicity, in vivo.

  3. Development of a Mist Singlet Oxygen Generator

    NASA Astrophysics Data System (ADS)

    Muto, Shigeki; Endo, Masamori; Nanri, Kenzo; Fujioka, Tomoo

    2002-08-01

    The singlet oxygen generator (SOG) generates singlet oxygen for a chemical oxygen iodine laser (COIL), using the gas-liquid reaction between basic hydrogen peroxide (BHP) and Cl2 gas. The Jet-SOG has been widely used, wherein jet BHP from small orifices reacts with Cl2 gas, and the BHP utilization is less than 1% in a single pass through the reaction zone. To improve BHP utilization, the reaction surface with Cl2 gas should be increased, and the droplet diameter of BHP should be decreased. In this study, two types of mist generators were tested for the SOG, with which 65-μm- and 15-μm-diameter droplets were generated. In the 65 μm mist generator, BHP utilization was 22.5% at the Cl2 flow rate of 8.3 mmol/s, and in the 15 μm mist generator, BHP utilization was 41.5% at the Cl2 flow rate of 9.0 mmol/s, that is, BHP utilization of the new SOG, Mist-SOG, markedly exceeded that of the conventional Jet-SOG.

  4. [Generation of new nerve cells in the adult human brain].

    PubMed

    Poulsen, Frantz Rom; Meyer, Morten; Rasmussen, Jens Zimmer

    2003-03-31

    Generation of new nerve cells (neurogenesis) is normally considered to be limited to the fetal and early postnatal period. Thus, damaged nerve cells are not expected to be replaced by generation of new cells. The brain is, however, more plastic than previously assumed. This also includes neurogenesis in the adult human brain. In particular two brain regions show continuous division of neural stem and progenitor cells generating neurons and glial cells, namely the subgranular zone of the dentate gyrus and the subventricular zones of the lateral ventricles. From the latter region newly generated neuroblasts (immature nerve cells) migrate toward the olfactory bulb where they differentiate into neurons. In the dentate gyrus the newly generated neurons become functionally integrated in the granule cell layer, where they are believed to be of importance to learning and memory. It is at present not known whether neurogenesis in the adult human brain can be manipulated for specific repair after brain damage.

  5. A Progenitor Cell Expressing Transcription Factor RORγt Generates All Human Innate Lymphoid Cell Subsets.

    PubMed

    Scoville, Steven D; Mundy-Bosse, Bethany L; Zhang, Michael H; Chen, Li; Zhang, Xiaoli; Keller, Karen A; Hughes, Tiffany; Chen, Luxi; Cheng, Stephanie; Bergin, Stephen M; Mao, Hsiaoyin C; McClory, Susan; Yu, Jianhua; Carson, William E; Caligiuri, Michael A; Freud, Aharon G

    2016-05-17

    The current model of murine innate lymphoid cell (ILC) development holds that mouse ILCs are derived downstream of the common lymphoid progenitor through lineage-restricted progenitors. However, corresponding lineage-restricted progenitors in humans have yet to be discovered. Here we identified a progenitor population in human secondary lymphoid tissues (SLTs) that expressed the transcription factor RORγt and was unique in its ability to generate all known ILC subsets, including natural killer (NK) cells, but not other leukocyte populations. In contrast to murine fate-mapping data, which indicate that only ILC3s express Rorγt, these human progenitor cells as well as human peripheral blood NK cells and all mature ILC populations expressed RORγt. Thus, all human ILCs can be generated through an RORγt(+) developmental pathway from a common progenitor in SLTs. These findings help establish the developmental signals and pathways involved in human ILC development.

  6. Generation of motor neurons from pluripotent stem cells.

    PubMed

    Chipman, Peter H; Toma, Jeremy S; Rafuse, Victor F

    2012-01-01

    Alpha motor neurons (also known as lower or skeletal motor neurons) have been studied extensively for over 100 years. Motor neurons control the contraction of skeletal muscles and thus are the final common pathway in the nervous system responsible for motor behavior. Muscles become paralyzed when their innervating motor neurons die because of injury or disease. Motor neuron diseases (MNDs), such as Amyotrophic Lateral Sclerosis, progressively destroy motor neurons until those inflicted succumb to the illness due to respiratory failure. One strategy being explored to study and treat muscle paralysis due to motor neuron loss involves deriving surrogate motor neurons from pluripotent stem cells. Guided by decades of research on the development of the spinal cord, recent advances in neurobiology have shown that functional motor neurons can be derived from mouse and human embryonic stem (ES) cells. Furthermore, ES cell-derived motor neurons restore motor behavior when transplanted into animal models of motor dysfunction. The recent discovery that mouse and human motor neurons can be derived from induced pluripotent stem (iPS) cells (i.e., somatic cells converted to pluripotency) has set the stage for the development of patient-specific therapies designed to treat movement disorders. Indeed, there is now hope within the scientific community that motor neurons derived from pluripotent stem cells will be used to treat MNDs through cell transplantation and/or to screen molecules that will prevent motor neuron death. In this chapter, we review the journey that led to the generation of motor neurons from ES and iPS cells, how stem cell-derived motor neurons have been used to treat/study motor dysfunction, and where the technology will likely lead to in the future.

  7. Releasing Dentate Nucleus Cells from Purkinje Cell Inhibition Generates Output from the Cerebrocerebellum

    PubMed Central

    Ishikawa, Takahiro; Tomatsu, Saeka; Tsunoda, Yoshiaki; Lee, Jongho; Hoffman, Donna S.; Kakei, Shinji

    2014-01-01

    The cerebellum generates its vast amount of output to the cerebral cortex through the dentate nucleus (DN) that is essential for precise limb movements in primates. Nuclear cells in DN generate burst activity prior to limb movement, and inactivation of DN results in cerebellar ataxia. The question is how DN cells become active under intensive inhibitory drive from Purkinje cells (PCs). There are two excitatory inputs to DN, mossy fiber and climbing fiber collaterals, but neither of them appears to have sufficient strength for generation of burst activity in DN. Therefore, we can assume two possible mechanisms: post-inhibitory rebound excitation and disinhibition. If rebound excitation works, phasic excitation of PCs and a concomitant inhibition of DN cells should precede the excitation of DN cells. On the other hand, if disinhibition plays a primary role, phasic suppression of PCs and activation of DN cells should be observed at the same timing. To examine these two hypotheses, we compared the activity patterns of PCs in the cerebrocerebellum and DN cells during step-tracking wrist movements in three Japanese monkeys. As a result, we found that the majority of wrist-movement-related PCs were suppressed prior to movement onset and the majority of wrist-movement-related DN cells showed concurrent burst activity without prior suppression. In a minority of PCs and DN cells, movement-related increases and decreases in activity, respectively, developed later. These activity patterns suggest that the initial burst activity in DN cells is generated by reduced inhibition from PCs, i.e., by disinhibition. Our results indicate that suppression of PCs, which has been considered secondary to facilitation, plays the primary role in generating outputs from DN. Our findings provide a new perspective on the mechanisms used by PCs to influence limb motor control and on the plastic changes that underlie motor learning in the cerebrocerebellum. PMID:25279763

  8. Genetic engineering of hematopoietic stem cells to generate invariant natural killer T cells.

    PubMed

    Smith, Drake J; Liu, Siyuan; Ji, Sunjong; Li, Bo; McLaughlin, Jami; Cheng, Donghui; Witte, Owen N; Yang, Lili

    2015-02-03

    Invariant natural killer T (iNKT) cells comprise a small population of αβ T lymphocytes. They bridge the innate and adaptive immune systems and mediate strong and rapid responses to many diseases, including cancer, infections, allergies, and autoimmunity. However, the study of iNKT cell biology and the therapeutic applications of these cells are greatly limited by their small numbers in vivo (∼0.01-1% in mouse and human blood). Here, we report a new method to generate large numbers of iNKT cells in mice through T-cell receptor (TCR) gene engineering of hematopoietic stem cells (HSCs). We showed that iNKT TCR-engineered HSCs could generate a clonal population of iNKT cells. These HSC-engineered iNKT cells displayed the typical iNKT cell phenotype and functionality. They followed a two-stage developmental path, first in thymus and then in the periphery, resembling that of endogenous iNKT cells. When tested in a mouse melanoma lung metastasis model, the HSC-engineered iNKT cells effectively protected mice from tumor metastasis. This method provides a powerful and high-throughput tool to investigate the in vivo development and functionality of clonal iNKT cells in mice. More importantly, this method takes advantage of the self-renewal and longevity of HSCs to generate a long-term supply of engineered iNKT cells, thus opening up a new avenue for iNKT cell-based immunotherapy.

  9. SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

    SciTech Connect

    Unknown

    2002-03-01

    This report summarizes the work performed by Honeywell during the July 2001 to September 2001 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. An internal program kickoff was held at Honeywell in Torrance, CA. The program structure was outlined and the overall technical approach for the program was presented to the team members. Detail program schedules were developed and detailed objectives were defined. Initial work has begun on the system design and pressurized SOFC operation.

  10. SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

    SciTech Connect

    Kurt Montgomery; Nguyen Minh

    2003-08-01

    This report summarizes the work performed by Honeywell during the October 2001 to December 2001 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The conceptual and demonstration system designs were proposed and analyzed, and these systems have been modeled in Aspen Plus. Work has also started on the assembly of dynamic component models and the development of the top-level controls requirements for the system. SOFC stacks have been fabricated and performance mapping initiated.

  11. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh

    2002-03-31

    This report summarizes the work performed by Honeywell during the January 2002 to March 2002 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. For this reporting period the following activities have been carried out: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} System-level performance model was created {lg_bullet} Dynamic control models are being developed {lg_bullet} Mechanical properties of candidate heat exchanger materials were investigated {lg_bullet} SOFC performance mapping as a function of flow rate and pressure was completed

  12. Sensors based on galvanic cell generated electrochemiluminescence and its application.

    PubMed

    Luo, Lirong; Zhang, Zhujun

    2006-10-27

    In this paper, a novel electrochemiluminescence (ECL) imaging sensor array was developed for determination of hydrogen peroxide (H2O2), which was based on Cu/Zn alloy galvanic cell generated ECL. In alkaline solution, Cu/Zn galvanic cell was formed because of corrosion effect, the galvanic cell could supply stable potential for ECL generation of luminol, and the weak ECL emission could be enhanced by H(2)O(2). The galvanic cell sensor array was designed by putting Cu/Zn alloy in 96-well microtiter plates separately. The relative ECL intensity was proportional with the concentration of hydrogen peroxide in the range of 1.0 x 10(-6) to 1.0 x 10(-4) mol l(-1) and the detection limit was 3.0 x 10(-7) mol l(-1) (3sigma), the relative standard deviation (R.S.D.) for 11 parallel measurements of 1.0 x 10(-5)mol l(-1) H2O2 was 4.0%.

  13. Generation of beta cells from human pluripotent stem cells: Potential for regenerative medicine.

    PubMed

    Nostro, Maria Cristina; Keller, Gordon

    2012-08-01

    The loss of beta cells in Type I diabetes ultimately leads to insulin dependence and major complications that are difficult to manage by insulin injections. Given the complications associated with long-term administration of insulin, cell-replacement therapy is now under consideration as an alternative treatment that may someday provide a cure for this disease. Over the past 10 years, islet transplantation trials have demonstrated that it is possible to replenish beta cell function in Type I diabetes patients and, at least temporarily, eliminate their dependency on insulin. While not yet optimal, the success of these trials has provided proof-of-principle that cell replacement therapy is a viable option for treating diabetes. Limited access to donor islets has launched a search for alternative source of beta cells for cell therapy purposes and focused the efforts of many investigators on the challenge of deriving such cells from human embryonic (hESCs) and induced pluripotent stem cells (hiPSCs). Over the past five years, significant advances have been made in understanding the signaling pathways that control lineage development from human pluripotent stem cells (hPSCs) and as a consequence, it is now possible to routinely generate insulin producing cells from both hESCs and hiPSCs. While these achievements are impressive, significant challenges do still exist, as the majority of insulin producing cells generated under these conditions are polyhormonal and non functional, likely reflecting the emergence of the polyhormonal population that is known to arise in the early embryo during the phase of pancreatic development known as the 'first transition'. Functional beta cells, which arise during the second phase or transition of pancreatic development have been generated from hESCs, however they are detected only following transplantation of progenitor stage cells into immunocompromised mice. With this success, our challenge now is to define the pathways that control

  14. Tubular solid oxide fuel cell developments

    NASA Astrophysics Data System (ADS)

    Bratton, R. J.; Singh, P.

    An overview of the tubular solid oxide fuel cell (SOFC) development at Westinghouse is presented in this paper. The basic operating principles of SOFC's, evolution in tubular cell design and performance improvement, selection criteria for cell component materials, and cell processing techniques are discussed. The commercial goal is to develop a cell that can operate for 5 to 10 years. Results of cell test operated for more than 50,000 hours are presented. Since 1986, significant progress has been made in the evolution of cells with higher power, lower cost and improved thermal cyclic capability. Also in this period, successively larger multi-kilowatt electrical generators systems have been built and successfully operated for more than 7000 hours.

  15. Tubular solid oxide fuel cell developments

    SciTech Connect

    Bratton, R.J.; Singh, P.

    1995-08-01

    An overview of the tubular solid oxide fuel cell (SOFC) development at Westinghouse is presented in this paper. The basic operating principles of SOFCs, evolution in tubular cell design and performance improvement, selection criteria for cell component materials, and cell processing techniques are discussed. The commercial goal is to develop a cell that can operate for 5 to 10 years. Results of cell test operated for more than 50,000 hours are presented. Since 1986, significant progress has been made in the evolution of cells with higher power, lower cost and improved thermal cyclic capability. Also in this period, successively larger multi-kilowatt electrical generators systems have been built and successfully operated for more than 7000 hours.

  16. Assessment of a Solar Cell Panel Spatial Arrangement Influence on Electricity Generation

    NASA Astrophysics Data System (ADS)

    Anisimov, I. A.; Burakova, L. N.; Burakova, A. D.; Burakova, O. D.

    2017-05-01

    The research evaluates the impact of the spatial arrangement of solar cell panels on the amount of electricity generated (power generated by solar cell panel) in Tyumen. Dependences of the power generated by the solar panel on the time of day, air temperature, weather conditions and the spatial arrangement are studied. Formulas for the calculation of the solar cell panel inclination angle which provides electricity to urban infrastructure are offered. Based on the data in the future, changing of inclination angle of solar cell panel will be confirmed experimentally during the year in Tyumen, and recommendations for installing solar cell panels in urban infrastructure will be developed.

  17. Design and development of thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Prem Kumar, D. S.; Mahajan, Ishan Vardhan; Anbalagan, R.; Mallik, Ramesh Chandra

    2014-04-01

    In this paper we discuss the fabrication, working and characteristics of a thermoelectric generator made up of p and n type semiconductor materials. The device consists of Fe0.2Co3.8Sb11.5Te0.5 (zT = 1.04 at 818 K) as the n-type and Zn4Sb3 (zT=0.8 at 550 K) as the p-type material synthesized by vacuum hot press method. Carbon paste has been used to join the semiconductor legs to metal (Molybdenum) electrodes to reduce the contact resistance. The multi-couple (4 legs) generator results a maximum output power of 1.083 mW at a temperature difference of 240 K between the hot and cold sides. In this investigation, an I-V characteristic, maximum output power of the thermoelectric module is presented. The efficiency of thermoelectric module is obtained as η = 0.273 %.

  18. Generation of kidney tubular organoids from human pluripotent stem cells

    PubMed Central

    Yamaguchi, Shintaro; Morizane, Ryuji; Homma, Koichiro; Monkawa, Toshiaki; Suzuki, Sayuri; Fujii, Shizuka; Koda, Muneaki; Hiratsuka, Ken; Yamashita, Maho; Yoshida, Tadashi; Wakino, Shu; Hayashi, Koichi; Sasaki, Junichi; Hori, Shingo; Itoh, Hiroshi

    2016-01-01

    Recent advances in stem cell research have resulted in methods to generate kidney organoids from human pluripotent stem cells (hPSCs), which contain cells of multiple lineages including nephron epithelial cells. Methods to purify specific types of cells from differentiated hPSCs, however, have not been established well. For bioengineering, cell transplantation, and disease modeling, it would be useful to establish those methods to obtain pure populations of specific types of kidney cells. Here, we report a simple two-step differentiation protocol to generate kidney tubular organoids from hPSCs with direct purification of KSP (kidney specific protein)-positive cells using anti-KSP antibody. We first differentiated hPSCs into mesoderm cells using a glycogen synthase kinase-3β inhibitor for 3 days, then cultured cells in renal epithelial growth medium to induce KSP+ cells. We purified KSP+ cells using flow cytometry with anti-KSP antibody, which exhibited characteristics of all segments of kidney tubular cells and cultured KSP+ cells in 3D Matrigel, which formed tubular organoids in vitro. The formation of tubular organoids by KSP+ cells induced the acquisition of functional kidney tubules. KSP+ cells also allowed for the generation of chimeric kidney cultures in which human cells self-assembled into 3D tubular structures in combination with mouse embryonic kidney cells. PMID:27982115

  19. Microbial fuel cells: novel biotechnology for energy generation.

    PubMed

    Rabaey, Korneel; Verstraete, Willy

    2005-06-01

    Microbial fuel cells (MFCs) provide new opportunities for the sustainable production of energy from biodegradable, reduced compounds. MFCs function on different carbohydrates but also on complex substrates present in wastewaters. As yet there is limited information available about the energy metabolism and nature of the bacteria using the anode as electron acceptor; few electron transfer mechanisms have been established unequivocally. To optimize and develop energy production by MFCs fully this knowledge is essential. Depending on the operational parameters of the MFC, different metabolic pathways are used by the bacteria. This determines the selection and performance of specific organisms. Here we discuss how bacteria use an anode as an electron acceptor and to what extent they generate electrical output. The MFC technology is evaluated relative to current alternatives for energy generation.

  20. Generation of induced pluripotent stem cells from domestic goats.

    PubMed

    Sandmaier, Shelley E S; Nandal, Anjali; Powell, Anne; Garrett, Wesley; Blomberg, Leann; Donovan, David M; Talbot, Neil; Telugu, Bhanu P

    2015-09-01

    The creation of genetically modified goats provides a powerful approach for improving animal health, enhancing production traits, animal pharming, and for ensuring food safety all of which are high-priority goals for animal agriculture. The availability of goat embryonic stem cells (ESCs) that are characteristically immortal in culture would be of enormous benefit for developing genetically modified animals. As an alternative to long-sought goat ESCs, we generated induced pluripotent stem cells (iPSC) by forced expression of bovine POU5F1, SOX2, MYC, KLF4, LIN-28, and NANOG reprogramming factors in combination with a MIR302/367 cluster, delivered by lentiviral vectors. In order to minimize integrations, the reprogramming factor coding sequences were assembled with porcine teschovirus-1 2A (P2A) self-cleaving peptides that allowed for tri-cistronic expression from each vector. The lentiviral-transduced cells were cultured on irradiated mouse feeder cells in a semi-defined, serum-free medium containing fibroblast growth factor (FGF) and/or leukemia inhibitory factor (LIF). The resulting goat iPSC exhibit cell and colony morphology typical of human and mouse ESCs-that is, well-defined borders, a high nuclear-to-cytoplasmic ratio, a short cell-cycle interval, alkaline phosphatase expression, and the ability to generate teratomas in vivo. Additionally, these goat iPSC demonstrated the ability to differentiate into directed lineages in vitro. These results constitute the first steps in establishing integration and footprint-free iPSC from ruminants. Mol. Reprod. Dev. 82: 709-721, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  1. Generation of hair cells by stepwise differentiation of embryonic stem cells.

    PubMed

    Li, Huawei; Roblin, Graham; Liu, Hong; Heller, Stefan

    2003-11-11

    The increase in life expectancy is accompanied by the growing burden of chronic diseases. Hearing loss is perhaps the most prevalent of all chronic diseases. In addition to age-related hearing loss, a substantial number of cases of audiological impairment are either congenital in nature or acquired during childhood. The permanence of hearing loss is mainly due to the inability of the cochlear sensory epithelium to replace lost mechanoreceptor cells, or hair cells. Generation of hair cells from a renewable source of progenitors that can be transplanted into damaged inner ears is a principal requirement for potential cell replacement therapy in this organ. Here, we present an experimental protocol that enables us to routinely create inner ear progenitors from murine embryonic stem cells in vitro. These progenitors express a comprehensive set of marker genes that define the developing inner ear, in particular the organ's developing sensory patches. We further demonstrate that cells that express markers characteristic of hair cells differentiate from embryonic stem cell-derived progenitors. Finally, we show that these progenitors integrate into the developing inner ear at sites of epithelial injury and that integrated cells start expressing hair cell markers and display hair bundles when situated in cochlear or vestibular sensory epithelia in vivo.

  2. Retinoic acid promotes the generation of pancreatic endocrine progenitor cells and their further differentiation into beta-cells.

    PubMed

    Oström, Maria; Loffler, Kelly A; Edfalk, Sara; Selander, Lars; Dahl, Ulf; Ricordi, Camillo; Jeon, Jongmin; Correa-Medina, Mayrin; Diez, Juan; Edlund, Helena

    2008-07-30

    The identification of secreted factors that can selectively stimulate the generation of insulin producing beta-cells from stem and/or progenitor cells represent a significant step in the development of stem cell-based beta-cell replacement therapy. By elucidating the molecular mechanisms that regulate the generation of beta-cells during normal pancreatic development such putative factors may be identified. In the mouse, beta-cells increase markedly in numbers from embryonic day (e) 14.5 and onwards, but the extra-cellular signal(s) that promotes the selective generation of beta-cells at these stages remains to be identified. Here we show that the retinoic acid (RA) synthesizing enzyme Raldh1 is expressed in developing mouse and human pancreas at stages when beta-cells are generated. We also provide evidence that RA induces the generation of Ngn3(+) endocrine progenitor cells and stimulates their further differentiation into beta-cells by activating a program of cell differentiation that recapitulates the normal temporal program of beta-cell differentiation.

  3. Adhesion-Dependent Wave Generation in Crawling Cells.

    PubMed

    Barnhart, Erin L; Allard, Jun; Lou, Sunny S; Theriot, Julie A; Mogilner, Alex

    2017-01-09

    Dynamic actin networks are excitable. In migrating cells, feedback loops can amplify stochastic fluctuations in actin dynamics, often resulting in traveling waves of protrusion. The precise contributions of various molecular and mechanical interactions to wave generation have been difficult to disentangle, in part due to complex cellular morphodynamics. Here we used a relatively simple cell type-the fish epithelial keratocyte-to define a set of mechanochemical feedback loops underlying actin network excitability and wave generation. Although keratocytes are normally characterized by the persistent protrusion of a broad leading edge, increasing cell-substrate adhesion strength results in waving protrusion of a short leading edge. We show that protrusion waves are due to fluctuations in actin polymerization rates and that overexpression of VASP, an actin anti-capping protein that promotes actin polymerization, switches highly adherent keratocytes from waving to persistent protrusion. Moreover, VASP localizes both to adhesion complexes and to the leading edge. Based on these results, we developed a mathematical model for protrusion waves in which local depletion of VASP from the leading edge by adhesions-along with lateral propagation of protrusion due to the branched architecture of the actin network and negative mechanical feedback from the cell membrane-results in regular protrusion waves. Consistent with our model simulations, we show that VASP localization at the leading edge oscillates, with VASP leading-edge enrichment greatest just prior to protrusion initiation. We propose that the mechanochemical feedbacks underlying wave generation in keratocytes may constitute a general module for establishing excitable actin dynamics in other cellular contexts.

  4. A simple and versatile microfluidic cell density gradient generator for quantum dot cytotoxicity assay.

    PubMed

    Wu, Jing; Chen, Qiushui; Liu, Wu; Lin, Jin-Ming

    2013-05-21

    In this work, a simple and versatile microfluidic cell density gradient generator was successfully developed for cytotoxicity of quantum dots (QDs) assay. The microfluidic cell density gradient generator is composed of eight parallel channels which are respectively surrounded by 1-8 microwells with optimized length and width. The cells fall into microwells by gravity and the cell densities are obviously dependent of microwell number. In a case study, HepG2 and MCF-7 cells were successfully utilized for generating cell density gradients on the microfluidic chip. The microfluidic cell density gradient generator was proved to be easily handled, cell-friendly and could be used to conduct the subsequent cell-based assay. As a proof-of-concept, QD cytotoxicity was evaluated and the results exhibited obvious cell density-dependence. For comparison, QD cytotoxicity was also investigated with a series of cell densities infused by pipette tips. Higher reproducibility was observed on the microfluidic cell density gradient generator and cell density was demonstrated to be a vital factor in cytotoxic study. With higher efficiency, controllability and reproducibility, the microfluidic cell density gradient generator could be integrated into microfluidic analysis systems to promote chip-based biological assay.

  5. Development of an Influenza A Master Virus for Generating High-Growth Reassortants for A/Anhui/1/2013(H7N9) Vaccine Production in Qualified MDCK Cells.

    PubMed

    Suzuki, Yasushi; Odagiri, Takato; Tashiro, Masato; Nobusawa, Eri

    2016-01-01

    In 2013, the first case of human infection with an avian influenza A virus (H7N9) was reported in China, and the human infection with this virus has continued as of 2016. At the request of the WHO, we have successfully developed candidate reassortant vaccine virus using A/Anhui/1/2013 and the high egg-growth master virus A/PR/8/1934. Recent plans regarding influenza vaccine production include using cell-cultured systems in Japan and several other countries. However, egg-based vaccine viruses are not always suitable for cell-cultured vaccine production due to potential issues with growth, protein yield and antigenic stability. Therefore, in this study, we have developed a high-growth master virus (hg-PR8) adapted to qualified NIID-MDCK cells that are competent for vaccine production. The virus hg-PR8 was obtained after 20 serial passages of A/Puerto Rico/8/1934 (PR8) in NIID-MDCK cells. The viral titer of hg-PR8 was 108.6 plaque-forming units per milliliter (PFU/mL). Seven amino acid substitutions were identified in the amino acid sequences of PB2, PB1, PA, NA, M and NS of hg-PR8 compared to the sequence of the original PR8 (org-PR8) strain. The growth capacities of the reassortant viruses, which possess heterologous internal genes from hg-PR8 or org-PR8, indicated that the amino acid changes in PB2 and NS2 similarly affected growth capacity in NIID-MDCK cells. To assess the suitability of hg-PR8 as a master virus, we generated 6:2 reassortant viruses possessing the HA and NA segments from A/Anhui/1/2013 (H7N9) and the remaining segments from hg-PR8. The virus titers of the reassortant strains were 107-108 PFU/mL. The antigenicity of the viruses was stable during ten passages of the viruses in NIID-MDCK cells. In comparison with the egg-based reassortant vaccine viruses with identical HA and NA segments, the hg-PR8-based viruses showed 1.5- to 2-fold higher protein yields in NIID-MDCK cells.

  6. Development of an Influenza A Master Virus for Generating High-Growth Reassortants for A/Anhui/1/2013(H7N9) Vaccine Production in Qualified MDCK Cells

    PubMed Central

    Suzuki, Yasushi; Odagiri, Takato; Tashiro, Masato; Nobusawa, Eri

    2016-01-01

    In 2013, the first case of human infection with an avian influenza A virus (H7N9) was reported in China, and the human infection with this virus has continued as of 2016. At the request of the WHO, we have successfully developed candidate reassortant vaccine virus using A/Anhui/1/2013 and the high egg-growth master virus A/PR/8/1934. Recent plans regarding influenza vaccine production include using cell-cultured systems in Japan and several other countries. However, egg-based vaccine viruses are not always suitable for cell-cultured vaccine production due to potential issues with growth, protein yield and antigenic stability. Therefore, in this study, we have developed a high-growth master virus (hg-PR8) adapted to qualified NIID-MDCK cells that are competent for vaccine production. The virus hg-PR8 was obtained after 20 serial passages of A/Puerto Rico/8/1934 (PR8) in NIID-MDCK cells. The viral titer of hg-PR8 was 108.6 plaque-forming units per milliliter (PFU/mL). Seven amino acid substitutions were identified in the amino acid sequences of PB2, PB1, PA, NA, M and NS of hg-PR8 compared to the sequence of the original PR8 (org-PR8) strain. The growth capacities of the reassortant viruses, which possess heterologous internal genes from hg-PR8 or org-PR8, indicated that the amino acid changes in PB2 and NS2 similarly affected growth capacity in NIID-MDCK cells. To assess the suitability of hg-PR8 as a master virus, we generated 6:2 reassortant viruses possessing the HA and NA segments from A/Anhui/1/2013 (H7N9) and the remaining segments from hg-PR8. The virus titers of the reassortant strains were 107−108 PFU/mL. The antigenicity of the viruses was stable during ten passages of the viruses in NIID-MDCK cells. In comparison with the egg-based reassortant vaccine viruses with identical HA and NA segments, the hg-PR8-based viruses showed 1.5- to 2-fold higher protein yields in NIID-MDCK cells. PMID:27454606

  7. Ex-vivo generation of human red cells for transfusion.

    PubMed

    Anstee, David J; Gampel, Alexandra; Toye, Ashley M

    2012-05-01

    The present article reviews the recent data concerning the generation of red blood cells from haematopoietic stem cells using laboratory culture and discusses the potential for generating cultured red cells in sufficient quantity for use in transfusion practice. Functional human reticulocytes have been generated from adult peripheral blood haematopoietic stem cells in laboratory culture without the use of heterologous feeder cells and their viability was demonstrated in vivo. Human erythroid progenitor cells lines have been produced from cord and human induced pluripotent stem cell (hiPSC) haematopoietic progenitors. Availability of cultured human red cells from haematopoietic stem cells in the quantities required for transfusion therapy would have a major impact on healthcare provision worldwide. Recent studies provide cause for optimism that this ambitious goal is achievable. Functional adult reticulocytes have been made in culture and shown to survive in vivo. Erythroid progenitor cell lines have been derived from cord blood and from human induced pluripotent stem cells, suggesting that large-scale culture of erythroid cell lines and their differentiation to reticulocytes will be possible. Significant problems remain. More efficient enucleation and induction of maturation to an adult phenotype will be required in order to exploit high proliferative capacity of human embryonic stem cells and hiPSCs. Novel bioengineering solutions will be required to generate cultured red cells in the large quantities required, and in this context, use of synthetic three-dimensional scaffolds to mimic the bone marrow niche holds great promise for the future.

  8. Generation of pluripotent stem cells from adult human testis.

    PubMed

    Conrad, Sabine; Renninger, Markus; Hennenlotter, Jörg; Wiesner, Tina; Just, Lothar; Bonin, Michael; Aicher, Wilhelm; Bühring, Hans-Jörg; Mattheus, Ulrich; Mack, Andreas; Wagner, Hans-Joachim; Minger, Stephen; Matzkies, Matthias; Reppel, Michael; Hescheler, Jürgen; Sievert, Karl-Dietrich; Stenzl, Arnulf; Skutella, Thomas

    2008-11-20

    Human primordial germ cells and mouse neonatal and adult germline stem cells are pluripotent and show similar properties to embryonic stem cells. Here we report the successful establishment of human adult germline stem cells derived from spermatogonial cells of adult human testis. Cellular and molecular characterization of these cells revealed many similarities to human embryonic stem cells, and the germline stem cells produced teratomas after transplantation into immunodeficient mice. The human adult germline stem cells differentiated into various types of somatic cells of all three germ layers when grown under conditions used to induce the differentiation of human embryonic stem cells. We conclude that the generation of human adult germline stem cells from testicular biopsies may provide simple and non-controversial access to individual cell-based therapy without the ethical and immunological problems associated with human embryonic stem cells.

  9. Development of a Ship Service Fuel Cell

    DTIC Science & Technology

    2000-10-01

    Sanderson FuelCell Energy, Inc. 3 Great Pasture Road Danbury, CT 06811 USA sabens@fce.com Sommaire Sous un programme � trois phases commandit� par...lÕOffice of Naval Research (ONR), FuelCell Energy, Inc. est en train de d�velopper une centrale � piles � combustible de 2,5 MW pour la production dÕ...sponsored by the Office of Naval Research (ONR), FuelCell Energy, Inc. is developing a 2.5 MW fuel cell power plant for ship service power generation

  10. Reprogramming of fetal cells by avian EE for generation of pluripotent stem cell like cells in caprine.

    PubMed

    Bharadwaj, Parul; Kumar, Kuldeep; Singh, Renu; Puri, Gopal; Yasotha, T; Kumar, Manish; Bhure, Sanjeev; Das, B C; Sarkar, M; Bag, Sadhan

    2013-10-01

    The present work was carried out to study the ability of avian "Extract Egg" (EE) for reprogramming caprine fetal cells. The isolated caprine fetal cells were cultured in stem cell media supplemented with different percentages of either EE or FBS. The results indicated that the supplementation of 2-4% EE formed lesser but larger size stem cell like cell colonies as compared to 6% or 10% EE. The expression of pluripotent genes were comparatively higher in colonies developed in 2% or 4% as compared to 6% or 10% EE. Further, immunocytochemistry revealed that the colonies developed in all percentage of EE expressed pluripotent markers like Oct4, Nanog, TRA-1-60 and TRA-1-81. Our findings indicated that avian EE has the potentiality to reprogram caprine fetal cells into embryonic state which may help in generation of pluripotent stem cells without using viral vector. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Design and development of thermoelectric generator

    SciTech Connect

    Prem Kumar, D. S. Mahajan, Ishan Vardhan Anbalagan, R. Mallik, Ramesh Chandra

    2014-04-24

    In this paper we discuss the fabrication, working and characteristics of a thermoelectric generator made up of p and n type semiconductor materials. The device consists of Fe{sub 0.2}Co{sub 3.8}Sb{sub 11.5}Te{sub 0.5} (zT = 1.04 at 818 K) as the n-type and Zn4Sb3 (zT=0.8 at 550 K) as the p-type material synthesized by vacuum hot press method. Carbon paste has been used to join the semiconductor legs to metal (Molybdenum) electrodes to reduce the contact resistance. The multi-couple (4 legs) generator results a maximum output power of 1.083 mW at a temperature difference of 240 K between the hot and cold sides. In this investigation, an I-V characteristic, maximum output power of the thermoelectric module is presented. The efficiency of thermoelectric module is obtained as η = 0.273 %.

  12. Managerial Career Development and the Generational Confrontation

    ERIC Educational Resources Information Center

    Moment, David; Fisher, Dalmar

    1973-01-01

    The authors propose that the manager's total career life (total life space, middle level behavior alternatives subject to personal control, and interactive, interpersonal communication, focused on mutual career development) be considered in approaching career development, rather than artificially isolating segments of the individual's life. This…

  13. Fuel cell power plants in a distributed generator application

    SciTech Connect

    Smith, M.J.

    1996-12-31

    ONSI`s (a subsidiary of International Fuel Cells Corporation) world wide fleet of 200-kW PC25{trademark} phosphoric acid fuel cell power plants which began operation early in 1992 has shown excellent performance and reliability in over 1 million hours of operation. This experience has verified the clean, quiet, reliable operation of the PC25 and confirmed its application as a distributed generator. Continuing product development efforts have resulted in a one third reduction of weight and volume as well as improved installation and operating characteristics for the PC25 C model. Delivery of this unit began in 1995. International Fuel Cells (IFC) continues its efforts to improve product design and manufacturing processes. This progress has been sustained at a compounded rate of 10 percent per year since the late 1980`s. These improvements will permit further reductions in the initial cost of the power plant and place increased emphasis on market development as the pacing item in achieving business benefits from the PC25 fuel cell. Derivative product opportunities are evolving with maturation of the technologies in a commercial environment. The recent announcement of Praxair, Inc., and IFC introducing a non-cryogenic hydrogen supply system utilizing IFC`s steam reformer is an example. 11 figs.

  14. Generation of functional thyroid from embryonic stem cells

    PubMed Central

    Antonica, Francesco; Kasprzyk, Dominika Figini; Opitz, Robert; Iacovino, Michelina; Liao, Xiao-Hui; Dumitrescu, Alexandra Mihaela; Refetoff, Samuel; Peremans, Kathelijne; Manto, Mario; Kyba, Michael; Costagliola, Sabine

    2013-01-01

    The primary function of thyroid gland is to metabolize iodide by synthesizing thyroid hormones that are critical regulators of growth, development and metabolism in virtually all tissues. To date, research on thyroid morphogenesis was missing an efficient stem-cell model system which allows to recapitulate in vitro the molecular and morphogenic events regulating thyroid follicular cells differentiation and subsequent assembly into functional thyroid follicles. Here we report that a transient overexpression of the transcription factors NKX2.1 and PAX8 is sufficient to direct mouse embryonic stem-cells (mESC) differentiation into thyroid follicular cells which organized into three-dimensional follicular structures when treated with thyrotropin. Those in vitro derived follicles showed significant iodide organification activity. Importantly, when grafted in vivo into athyreoid mice, these follicles rescued thyroid hormone plasma levels and promoted subsequent symptomatic recovery. Thus, mESC can be induced to differentiate into thyroid follicular cells in vitro and generate functional thyroid tissue. PMID:23051751

  15. Generation of Viable Cell and Biomaterial Patterns by Laser Transfer

    NASA Astrophysics Data System (ADS)

    Ringeisen, Bradley

    2001-03-01

    In order to fabricate and interface biological systems for next generation applications such as biosensors, protein recognition microarrays, and engineered tissues, it is imperative to have a method of accurately and rapidly depositing different active biomaterials in patterns or layered structures. Ideally, the biomaterial structures would also be compatible with many different substrates including technologically relevant platforms such as electronic circuits or various detection devices. We have developed a novel laser-based technique, termed matrix assisted pulsed laser evaporation direct write (MAPLE DW), that is able to direct write patterns and three-dimensional structures of numerous biologically active species ranging from proteins and antibodies to living cells. Specifically, we have shown that MAPLE DW is capable of forming mesoscopic patterns of living prokaryotic cells (E. coli bacteria), living mammalian cells (Chinese hamster ovaries), active proteins (biotinylated bovine serum albumin, horse radish peroxidase), and antibodies specific to a variety of classes of cancer related proteins including intracellular and extracellular matrix proteins, signaling proteins, cell cycle proteins, growth factors, and growth factor receptors. In addition, patterns of viable cells and active biomolecules were deposited on different substrates including metals, semiconductors, nutrient agar, and functionalized glass slides. We will present an explanation of the laser-based transfer mechanism as well as results from our recent efforts to fabricate protein recognition microarrays and tissue-based microfluidic networks.

  16. Septins and Generation of Asymmetries in Fungal Cells

    PubMed Central

    Khan, Anum; McQuilken, Molly

    2017-01-01

    Polarized growth is critical for the development and maintenance of diverse organisms and tissues, but particularly central to fungi where nutrient uptake, communication, and reproduction all rely on cell asymmetries. To achieve polarized growth, fungi spatially organize both their cytosol and cortical membranes. The septins, a family of GTP-binding proteins, have emerged as key regulators of spatial compartmentalization in fungi and other eukaryotes. By forming higher-order structures on fungal plasma membranes, septins are thought to contribute to the generation of cell asymmetries by acting as molecular scaffolds and forming diffusional barriers. Here we discuss the links between septins and polarized growth and consider molecular models for how septins contribute to cellular asymmetry in fungi. PMID:26488282

  17. Generation of germ cells in vitro in the era of induced pluripotent stem cells.

    PubMed

    Imamura, Masanori; Hikabe, Orie; Lin, Zachary Yu-Ching; Okano, Hideyuki

    2014-01-01

    Induced pluripotent stem cells (iPSCs) are stem cells that can be artificially generated via "cellular reprogramming" using gene transduction in somatic cells. iPSCs have enormous potential in stem-cell biology as they can give rise to numerous cell lineages, including the three germ layers. An evaluation of germ-line competency by blastocyst injection or tetraploid complementation, however, is critical for determining the developmental potential of mouse iPSCs towards germ cells. Recent studies have demonstrated that primordial germ cells obtained by the in vitro differentiation of iPSCs produce functional gametes as well as healthy offspring. These findings illustrate not only that iPSCs are developmentally similar to embryonic stem cells (ESCs), but also that somatic cells from adult tissues can produce gametes in vitro, that is, if they are reprogrammed into iPSCs. In this review, we discuss past and recent advances in the in vitro differentiation of germ cells using pluripotent stem cells, with an emphasis on ESCs and iPSCs. While this field of research is still at a stage of infancy, it holds great promises for investigating the mechanisms of germ-cell development, especially in humans, and for advancing reproductive and developmental engineering technologies in the future. © 2013 Wiley Periodicals, Inc.

  18. Developing a new generation of nurse entrepreneurs.

    PubMed

    Faugier, Jean

    This article reviews the policy implications associated with the creation of nurse entrepreneurs, the levels of progress achieved and the major obstacles to developing these roles. International experience and the cultural climate of the NHS in the U.K. are also discussed. The way in which entrepreneurial roles are evolving within the NHS and the future implications and developments for the wider not-for-profit and private sectors are explored.

  19. Generation and transmission improvements in developing countries

    SciTech Connect

    Hammons, T.J.; Willingham, M.; Mak, K.N.; Da Silva, M.; Morozowski, M.; Blyden, B.K.

    1999-09-01

    This paper discusses new realities in Power Development in Developing Countries as seen by the United Nations, The World Energy Council, Asia, Latin America, and Africa. At the outset, technical assistance given by the United Nations for global sustainability projects is summarized. Power system expansion and interconnection in China, greenhouse gas emission reduction in Egypt, and integrated development of the Arab-Mediterranean Regional and environmental considerations are among the projects that are highlighted. The pressing need of Developing Countries as seen by the World Energy Council to meet energy needs without prejudice to the environment where technological advances in the production, delivery and utilization of electrical energy are central to resolving conflicts between energy and the environment is then discussed. The paper goes on to discuss power system planning in deregulated environments where the Brazilian experience is highlighted. Global dynamics and potential for an integrated African Grid is then examined. Concepts associated with the growing interest in renewable resources in Central and East Africa for domestic, continental and international utilization are synthesized. Current and future energy development proposals are discussed with emphasis on operational reliability as a basis for potential large system design. Given are generalized representations to illustrate hydroelectric potential of the Central and East African regions and the kind of centralized pool that could be developed as a result. Other studies which include the Africa-Europe and Zaire-Egypt initiatives are also discussed.

  20. Distributed generation system using wind/photovoltaic/fuel cell

    NASA Astrophysics Data System (ADS)

    Buasri, Panhathai

    This dissertation investigates the performance and the operation of a distributed generation (DG) power system using wind/photovoltaic/fuel cell (W/PV/FC). The power system consists of a 2500 W photovoltaic array subsystem, a 500 W proton exchange membrane fuel cell (PEMFC) stack subsystem, 300 W wind turbine, 500 W wind turbine, and 1500 W wind energy conversion subsystems. To extract maximum power from the PV, a maximum power point tracker was designed and fabricated. A 4 kW single phase inverter was used to convert the DC voltage to AC voltage; also a 44 kWh battery bank was used to store energy and prevent fluctuation of the power output of the DG system. To connect the fuel cell to the batteries, a DC/DC controller was designed and fabricated. To monitor and study the performance of the DG system under variable conditions, a data acquisition system was designed and installed. The fuel cell subsystem performance was evaluated under standalone operation using a variable resistance and under interactive mode, connected to the batteries. The manufacturing data and the experimental data were used to develop an electrical circuit model to the fuel cell. Furthermore, harmonic analysis of the DG system was investigated. For an inverter, the AC voltage delivered to the grid changed depending on the time, load, and electronic equipment that was connected. The quality of the DG system was evaluated by investigating the harmonics generated by the power electronics converters. Finally, each individual subsystem of the DG system was modeled using the neuro-fuzzy approach. The model was used to predict the performance of the DG system under variable conditions, such as passing clouds and wind gust conditions. The steady-state behaviors of the model were validated by the experimental results under different operating conditions.

  1. Microscale Strategies for Generating Cell-Encapsulating Hydrogels

    PubMed Central

    Selimović, Šeila; Oh, Jonghyun; Bae, Hojae; Dokmeci, Mehmet; Khademhosseini, Ali

    2013-01-01

    Hydrogels in which cells are encapsulated are of great potential interest for tissue engineering applications. These gels provide a structure inside which cells can spread and proliferate. Such structures benefit from controlled microarchitectures that can affect the behavior of the enclosed cells. Microfabrication-based techniques are emerging as powerful approaches to generate such cell-encapsulating hydrogel structures. In this paper we introduce common hydrogels and their crosslinking methods and review the latest microscale approaches for generation of cell containing gel particles. We specifically focus on microfluidics-based methods and on techniques such as micromolding and electrospinning. PMID:23626908

  2. Corner heating in rectangular solid oxide electrochemical cell generators

    DOEpatents

    Reichner, Philip

    1989-01-01

    Disclosed is an improvement in a solid oxide electrochemical cell generator 1 having a rectangular design with four sides that meet at corners, and containing multiplicity of electrically connected fuel cells 11, where a fuel gas is passed over one side of said cells and an oxygen containing gas is passed into said cells, and said fuel is burned to form heat, electricity, and an exhaust gas. The improvement comprises passing the exhaust gases over the multiplicity of cells 11 in such a way that more of the heat in said exhaust gases flows at the corners of the generator, such as through channels 19.

  3. β-globin-expressing definitive erythroid progenitor cells generated from embryonic and induced pluripotent stem cell-derived sacs

    PubMed Central

    Fujita, Atsushi; Uchida, Naoya; Haro-Mora, Juan J.; Winkler, Thomas; Tisdale, John

    2016-01-01

    Human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells represent a potential alternative source for red blood cell transfusion. However, when using traditional methods with embryoid bodies, ES cell-derived erythroid cells predominantly express embryonic type ε-globin, with lesser fetal type γ-globin and very little adult type β-globin. Furthermore, no β-globin expression is detected in iPS cell-derived erythroid cells. ES cell-derived sacs (ES sacs) have been recently used to generate functional platelets. Due to its unique structure, we hypothesized that ES sacs serve as hemangioblast-like progenitors capable to generate definitive erythroid cells that express β-globin. With our ES sac-derived erythroid differentiation protocol, we obtained ~120 erythroid cells per single ES cell. Both primitive (ε-globin expressing) and definitive (γ- and β-globin expressing) erythroid cells were generated from not only ES cells but also iPS cells. Primitive erythropoiesis is gradually switched to definitive erythropoiesis during prolonged ES sac maturation, concurrent with the emergence of hematopoietic progenitor cells. Primitive and definitive erythroid progenitor cells were selected on the basis of GPA or CD34 expression from cells within the ES sacs before erythroid differentiation. This selection and differentiation strategy represents an important step toward the development of in vitro erythroid cell production systems from pluripotent stem cells. Further optimization to improve expansion should be required for clinical application. PMID:26866725

  4. Generation of Functional Lentoid Bodies From Human Induced Pluripotent Stem Cells Derived From Urinary Cells.

    PubMed

    Fu, Qiuli; Qin, Zhenwei; Jin, Xiuming; Zhang, Lifang; Chen, Zhijian; He, Jiliang; Ji, Junfeng; Yao, Ke

    2017-01-01

    The pathological mechanisms underlying cataract formation remain largely unknown on account of the lack of appropriate in vitro cellular models. The aim of this study is to develop a stable in vitro system for human lens regeneration using pluripotent stem cells. Isolated human urinary cells were infected with four Yamanaka factors to generate urinary human induced pluripotent stem cells (UiPSCs), which were induced to differentiate into lens progenitor cells and lentoid bodies (LBs). The expression of lens-specific markers was examined by real-time PCR, immunostaining, and Western blotting. The structure and magnifying ability of LBs were investigated using transmission electron microscopy and observing the magnification of the letter "X," respectively. We developed a "fried egg" differentiation method to generate functional LBs from UiPSCs. The UiPSC-derived LBs exhibited crystalline lens-like morphology and a transparent structure and expressed lens-specific markers αA-, αB-, β-, and γ-crystallin and MIP. During LB differentiation, the placodal markers SIX1, EYA1, DLX3, PAX6, and the specific early lens markers SOX1, PROX1, FOXE3, αA-, and αB-crystallin were observed at certain time points. Microscopic examination revealed the presence of lens epithelial cells adjacent to the lens capsule as well as both immature and mature fiber-like cells. Optical analysis further demonstrated the magnifying ability (1.7×) of the LBs generated from UiPSCs. Our study provides the first evidence toward generating functional LBs from UiPSCs, thereby establishing an in vitro system that can be used to study human lens development and cataractogenesis and perhaps even be useful for drug screening.

  5. Single module pressurized fuel cell turbine generator system

    DOEpatents

    George, Raymond A.; Veyo, Stephen E.; Dederer, Jeffrey T.

    2001-01-01

    A pressurized fuel cell system (10), operates within a common pressure vessel (12) where the system contains fuel cells (22), a turbine (26) and a generator (98) where preferably, associated oxidant inlet valve (52), fuel inlet valve (56) and fuel cell exhaust valve (42) are outside the pressure vessel.

  6. D-D neutron generator development at LBNL.

    PubMed

    Reijonen, J; Gicquel, F; Hahto, S K; King, M; Lou, T-P; Leung, K-N

    2005-01-01

    The plasma and ion source technology group in Lawrence Berkeley National Laboratory is developing advanced, next generation D-D neutron generators. There are three distinctive developments, which are discussed in this presentation, namely, multi-stage, accelerator-based axial neutron generator, high-output co-axial neutron generator and point source neutron generator. These generators employ RF-induction discharge to produce deuterium ions. The distinctive feature of RF-discharge is its capability to generate high atomic hydrogen species, high current densities and stable and long-life operation. The axial neutron generator is designed for applications that require fast pulsing together with medium to high D-D neutron output. The co-axial neutron generator is aimed for high neutron output with cw or pulsed operation, using either the D-D or D-T fusion reaction. The point source neutron generator is a new concept, utilizing a toroidal-shaped plasma generator. The beam is extracted from multiple apertures and focus to the target tube, which is located at the middle of the generator. This will generate a point source of D-D, T-T or D-T neutrons with high output flux. The latest development together with measured data will be discussed in this article.

  7. Psychological development in men: generativity and involvement with young children.

    PubMed

    Bailey, W T

    1992-12-01

    The personality development of 50 white men was investigated in terms of Eriksonian generativity and involvement with young children. Generativity was not related to caregiving; however, it was associated with social involvement. Generativity was also associated with several aspects of male personality including self-esteem, locus of control, and instrumentality.

  8. Patient-Specific Induced Pluripotent Stem Cell Models: Generation and Characterization of Cardiac Cells

    PubMed Central

    Zanella, Fabian; Sheikh, Farah

    2017-01-01

    The generation of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes has been of utmost interest for the study of cardiac development, cardiac disease modeling, and evaluation of cardiotoxic effects of novel candidate drugs. Several protocols have been developed to guide human stem cells toward the cardiogenic path. Pioneering work used serum to promote cardiogenesis; however, low cardiogenic throughputs, lack of chemical definition, and batch-to-batch variability of serum lots constituted a considerable impediment to the implementation of those protocols to large-scale cell biology. Further work focused on the manipulation of pathways that mouse genetics indicated to be fundamental in cardiac development to promote cardiac differentiation in stem cells. Although extremely elegant, those serum-free protocols involved the use of human recombinant cytokines that tend to be quite costly and which can also be variable between lots. The latest generation of cardiogenic protocols aimed for a more cost-effective and reproducible definition of the conditions driving cardiac differentiation, using small molecules to manipulate cardiogenic pathways overriding the need for cytokines. This chapter details methods based on currently available cardiac differentiation protocols for the generation and characterization of robust numbers of hiPSC-derived cardiomyocytes under chemically defined conditions. PMID:25520292

  9. Patient-Specific Induced Pluripotent Stem Cell Models: Generation and Characterization of Cardiac Cells.

    PubMed

    Zanella, Fabian; Sheikh, Farah

    2016-01-01

    The generation of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes has been of utmost interest for the study of cardiac development, cardiac disease modeling, and evaluation of cardiotoxic effects of novel candidate drugs. Several protocols have been developed to guide human stem cells toward the cardiogenic path. Pioneering work used serum to promote cardiogenesis; however, low cardiogenic throughputs, lack of chemical definition, and batch-to-batch variability of serum lots constituted a considerable impediment to the implementation of those protocols to large-scale cell biology. Further work focused on the manipulation of pathways that mouse genetics indicated to be fundamental in cardiac development to promote cardiac differentiation in stem cells. Although extremely elegant, those serum-free protocols involved the use of human recombinant cytokines that tend to be quite costly and which can also be variable between lots. The latest generation of cardiogenic protocols aimed for a more cost-effective and reproducible definition of the conditions driving cardiac differentiation, using small molecules to manipulate cardiogenic pathways overriding the need for cytokines. This chapter details methods based on currently available cardiac differentiation protocols for the generation and characterization of robust numbers of hiPSC-derived cardiomyocytes under chemically defined conditions.

  10. ZERO EMISSION POWER GENERATION TECHNOLOGY DEVELOPMENT

    SciTech Connect

    Ronald Bischoff; Stephen Doyle

    2005-01-20

    Clean Energy Systems (CES) was previously funded by DOE's ''Vision 21'' program. This program provided a proof-of-concept demonstration that CES' novel gas generator (combustor) enabled production of electrical power from fossil fuels without pollution. CES has used current DOE funding for additional design study exercises which established the utility of the CES-cycle for retrofitting existing power plants for zero-emission operations and for incorporation in zero-emission, ''green field'' power plant concepts. DOE funding also helped define the suitability of existing steam turbine designs for use in the CES-cycle and explored the use of aero-derivative turbines for advanced power plant designs. This work is of interest to the California Energy Commission (CEC) and the Norwegian Ministry of Petroleum & Energy. California's air quality districts have significant non-attainment areas in which CES technology can help. CEC is currently funding a CES-cycle technology demonstration near Bakersfield, CA. The Norwegian government is supporting conceptual studies for a proposed 40 MW zero-emission power plant in Stavager, Norway which would use the CES-cycle. The latter project is called Zero-Emission Norwegian Gas (ZENG). In summary, current engineering studies: (1) supported engineering design of plant subsystems applicable for use with CES-cycle zero-emission power plants, and (2) documented the suitability and availability of steam turbines for use in CES-cycle power plants, with particular relevance to the Norwegian ZENG Project.

  11. Hyaluronan Is Required for Generation of Hematopoietic Cells during Differentiation of Human Embryonic Stem Cells

    PubMed Central

    Schraufstatter, Ingrid U.; Serobyan, Naira; Loring, Jeanne; Khaldoyanidi, Sophia K.

    2010-01-01

    Hyaluronan (HA) is an important component of the microenvironment in bone marrow, but its role in regulation of the development of hematopoietic cells is not well understood. To address the role of HA in regulation of human embryonic stem cell (hESC) differentiation into the hematopoietic lineage, we screened for genes encoding components of the HA pathway. Using gene arrays, we found that HA synthases and HA receptors are expressed in both undifferentiated and differentiating hESCs. Enzymatic degradation of HA resulted in decreased numbers of hematopoietic progenitors and lower numbers of CD45+ cells generated in HA-deprived embryoid bodies (EBs). In addition, deprivation of HA resulted in the inhibition of generation of CD31+ cells, stromal fibroblast-like cells and contracting myocytes in EBs. RT-PCR and immunocytochemistry revealed that HA deprivation did not influence the dynamics of OCT4 expression, but decreased the expression of BRY, an early mesoderm marker, and BMP2, a later mesoderm marker in differentiating EBs. In addition, the endoderm markers α-FP and SOX17 were decreased, whereas the expression of the ectoderm markers GFAP and FGF5 was higher in HA-deprived cultures. Our findings indicate that endogenously produced HA contributes to the network that regulates the differentiation of hESC and the generation of mesodermal lineage in general and hematopoietic cells specifically. PMID:20861924

  12. Developing the next generation of nurse scientists.

    PubMed

    Burkhart, Patricia V; Hall, Lynne A

    2015-01-01

    This article describes an undergraduate nursing research internship program in which students are engaged in research with a faculty mentor. Since 2002, more than 130 undergraduate nursing students have participated. Interns coauthored publications, presented papers and posters at conferences, and received awards. This highly successful program provides a model that can be easily replicated to foster the development of future nurse scientists.

  13. Clinical grade of generation of dendritic cells for immunotherapy.

    PubMed

    Tang, Duozhuang; Tao, Si; Cao, Yang; Zhou, Jianfeng; Ma, Ding; Huang, Wei

    2007-06-01

    In order to develop a protocol for clinical grade generation of dendritic cells (DCs) for cancer immunotherapy, aphereses were performed with the continuous flow cell separator and materials were derived from 10 leukemia patients that had achieved complete remission. Peripheral blood monocytes were cultured in vitro with GM-CSF, IL-4 for 6 days, then TNF-(the TNF-group) or TNF-, IL-1, IL-6, PGE2 (the cytokine mixture group) were added to promote maturation. Cell number was counted by hematology analyzer, and phenotype study (CD1a, CD14, CD83) was carried out by flow cytometry, and the function of DCs was examined by mixed lymphocyte reaction. The results showed that (0.70+/-0.13)x10(7)/mL (the TNF-alpha group) and (0.79+/-0.04)x10(7)/mL (the cytokine mixture group) DCs were generated respectively in peripheral blood obtained by leucapheresis. The phenotypes were as follows: CD1a+ (74.65+/-4.45)%, CD83+ (39.50+/-4.16)%, CD14+ (2.90+/-1.76)% in TNF-alpha group, and CD1a+ (81.86+/-5.87)%, CD83+ (81.65+/-6.36)%, CD14+ (2.46+/-1.68)% in the cytokine mixture group. It was concluded that leucapheresis may be a feasible way to provide large number of peripheral blood monocytes for DC generation, and combined administration of TNF-, IL-1, IL-6, and PGE2 may greatly promote maturity.

  14. The role of OX40 (CD134) in T-cell memory generation.

    PubMed

    Weinberg, Andrew D

    2010-01-01

    Memory T-cell generation is limited by activation-induced cell death during the effector T-cell stage. Cell surface proteins are known to transmit signals that either accentuate or limit T-cell death after activation. This chapter will focus on the TNF-receptor family member OX40, which is expressed on effector T cells and when engaged greatly enhances survival of T cells leading to increased memory T-cell generation. Targeting OX40 in vivo can alter the fate ofT-cell survival. Enhancing OX40 signaling during Ag priming through agonists increases memory T-cell development, while blocking OX40 signaling decreases the memory T-cell pool. These two opposing outcomes provide therapeutic tools for blocking inflammation in autoimmune conditions and enhancing immunity in hosts harboring cancer or chronic pathogens. OX40 agonists and antagonists are in the first stages of human clinical trials and their therapeutic potential will soon be realized.

  15. Generation of murine sympathoadrenergic progenitor-like cells from embryonic stem cells and postnatal adrenal glands.

    PubMed

    Saxena, Shobhit; Wahl, Joachim; Huber-Lang, Markus S; Stadel, Dominic; Braubach, Peter; Debatin, Klaus-Michael; Beltinger, Christian

    2013-01-01

    Sympathoadrenergic progenitor cells (SAPs) of the peripheral nervous system (PNS) are important for normal development of the sympathetic PNS and for the genesis of neuroblastoma, the most common and often lethal extracranial solid tumor in childhood. However, it remains difficult to isolate sufficient numbers of SAPs for investigations. We therefore set out to improve generation of SAPs by using two complementary approaches, differentiation from murine embryonic stem cells (ESCs) and isolation from postnatal murine adrenal glands. We provide evidence that selecting for GD2 expression enriches for ESC-derived SAP-like cells and that proliferating SAP-like cells can be isolated from postnatal adrenal glands of mice. These advances may facilitate investigations about the development and malignant transformation of the sympathetic PNS.

  16. Generation of Murine Sympathoadrenergic Progenitor-Like Cells from Embryonic Stem Cells and Postnatal Adrenal Glands

    PubMed Central

    Saxena, Shobhit; Wahl, Joachim; Huber-Lang, Markus S.; Stadel, Dominic; Braubach, Peter; Debatin, Klaus-Michael; Beltinger, Christian

    2013-01-01

    Sympathoadrenergic progenitor cells (SAPs) of the peripheral nervous system (PNS) are important for normal development of the sympathetic PNS and for the genesis of neuroblastoma, the most common and often lethal extracranial solid tumor in childhood. However, it remains difficult to isolate sufficient numbers of SAPs for investigations. We therefore set out to improve generation of SAPs by using two complementary approaches, differentiation from murine embryonic stem cells (ESCs) and isolation from postnatal murine adrenal glands. We provide evidence that selecting for GD2 expression enriches for ESC-derived SAP-like cells and that proliferating SAP-like cells can be isolated from postnatal adrenal glands of mice. These advances may facilitate investigations about the development and malignant transformation of the sympathetic PNS. PMID:23675538

  17. Nanostructured photovoltaic devices for next generation solar cell

    NASA Astrophysics Data System (ADS)

    Kim, Sung Jin

    2008-10-01

    As the search for alternative sources of energy other than petroleum continues to expand, solar energy conversion has already been identified as one of the most promising technologies. In the past few years there has been extensive research focused on the next generation solar cells that can exceed the Shockley-Queisser limit (a model that predicts the maximum achievable efficiency for a given material with a given bandgap). Moreover, nanoengineering approaches to enhance solar power conversion efficiency have started to receive considerable interest. Even in the most efficient commercially available solar devices utilizing crystalline silicon, a major portion of the absorbed ultraviolet photon energy is wasted as heat. Furthermore, this heat is detrimental to device reliability. Colloidal nanocrystal quantum dots (NQDs) offer the exciting prospect of simultaneously manipulating device and material structures and processes to enable more efficient solar energy conversion. Most importantly, these colloidal nanocrystal quantum dots are amenable to inexpensive fabrication techniques such as dip coating or spray coating of the constituent nanoscale materials onto various substrates. This dissertation focuses on the development of nanostructured photovoltaic devices, that exhibit multiple exciton generation, and that exploit the wide absorption spectra enabled by the quantum dots for next generation highly efficient, low cost, solar cells. Firstly, multiple exciton generation and subsequent electrical extraction from a thin film photoconductive device constructed from PbSe NQDs is demonstrated. As an extension of this work, this PbSe NQD photoconductor was used in a tandem structure with a polymer solar cell to demonstrate multiple carrier extraction the application of an external electric field. This structure exhibited improved device durability from UV irradiation due to the self-passivating effect provided by the PbSe layer. In order to achieve better exciton

  18. Cell polarity-driven instability generates self-organized, fractal patterning of cell layers.

    PubMed

    Rudge, Timothy J; Federici, Fernán; Steiner, Paul J; Kan, Anton; Haseloff, Jim

    2013-12-20

    As a model system to study physical interactions in multicellular systems, we used layers of Escherichia coli cells, which exhibit little or no intrinsic coordination of growth. This system effectively isolates the effects of cell shape, growth, and division on spatial self-organization. Tracking the development of fluorescence-labeled cellular domains, we observed the emergence of striking fractal patterns with jagged, self-similar shapes. We then used a large-scale, cellular biophysical model to show that local instabilities due to polar cell-shape, repeatedly propagated by uniaxial growth and division, are responsible for generating this fractal geometry. Confirming this result, a mutant of E. coli with spherical shape forms smooth, nonfractal cellular domains. These results demonstrate that even populations of relatively simple bacterial cells can possess emergent properties due to purely physical interactions. Therefore, accurate physico-genetic models of cell growth will be essential for the design and understanding of genetically programmed multicellular systems.

  19. MEDEA II two-pulse generator development

    NASA Astrophysics Data System (ADS)

    Bieniosek, F. M.; Honig, J.; Theby, E. A.

    1990-06-01

    This article discusses improvements in the efficiency, output power, and operational flexibility of MEDEA II, a double-pulse electron beam accelerator at McDonnell Douglas Research Laboratories. A modified charging circuit, based on the triple-resonance pulse transformer concept, was implemented on both of MEDEA II's two stages. The output switches were modified to increase maximum output voltages, and a new, second output switch with asymmetric breakdown characteristics was developed. To avoid degradation of the second-pulse output waveform at the diode, a keep-alive circuit was installed. The effects of diode closure on double-pulse operation are also discussed.

  20. Cell cycle in mouse development.

    PubMed

    Ciemerych, Maria A; Sicinski, Peter

    2005-04-18

    Mice likely represent the most-studied mammalian organism, except for humans. Genetic engineering in embryonic stem cells has allowed derivation of mouse strains lacking particular cell cycle proteins. Analyses of these mutant mice, and cells derived from them, facilitated the studies of the functions of cell cycle apparatus at the organismal and cellular levels. In this review, we give some background about the cell cycle progression during mouse development. We next discuss some insights about in vivo functions of the cell cycle proteins, gleaned from mouse knockout experiments. Our text is meant to provide examples of the recent experiments, rather than to supply an extensive and complete list.

  1. Development of a low cost, portable solar hydrogen generation device

    NASA Astrophysics Data System (ADS)

    Rose, Kyle; Aggarwal, M. D.; Batra, Ashok; Wingo, Dennis

    2014-10-01

    Hydrogen is a clean energy source that is environmentally friendly and safe. It is well known that electrolysis is a common method used to produce hydrogen. Other high cost methods for hydrogen production can be countered by the development of this low cost pulse width modulated circuit, using direct current provided by naturally existing solar energy as a power source. Efforts are being made in the scientific community to produce a low cost, portable, solar hydrogen generating device for a number of clean energy applications such as fuel cells and energy storage. Proof of concept has already been tested in the laboratory and a small prototype system is being designed and fabricated in the workshop at Alabama A&M University. Our results of this study and details of the electronic circuit and the prototype are presented.

  2. Generation 6 Li-Ion Cell Vibration Testing at ABSL Space Products

    NASA Astrophysics Data System (ADS)

    Defer, M.; Borthomieu, Y.; Ligneel, E.; Badet, S.

    2014-08-01

    This paper presents the design of Saft's Generation6 Li-Ion cell, the main challenges in the course of the development, the main BOL characteristics and performances achieved during the development program. Finally, it also describes how this cell fits in Saft's battery range and the benefits of it.

  3. Organogenesis from dissociated cells: generation of mature cycling hair follicles from skin-derived cells.

    PubMed

    Zheng, Ying; Du, Xiabing; Wang, Wei; Boucher, Marylene; Parimoo, Satish; Stenn, Kurts

    2005-05-01

    Hair follicle formation and cycling involve extensive and continuous interactions between epithelial and mesenchymal components. A system for rapidly and reproducibly generating hair follicles from dissociated epithelial and mesenchymal cells is described here. The system serves both as a tool for measuring the trichogenic property of cells and as a tool for studying the mechanisms that dissociated cells use to assemble an organ. In this system, hair follicles develop when dissociated cells, isolated from newborn mouse skin, are injected into adult mouse truncal skin. This morphogenetic process involves the aggregation of epithelial cells to form clusters that are sculpted by apoptosis to generate "infundibular cysts". From the "infundibular cysts", hair germs form centrifugally followed by follicular buds and then pegs that grow asymmetrically to differentiate into cycling mature pilosebaceous structures. Marker studies correlate the molecular differentiation of these follicles with in situ systems. This study suggests that the earliest phase of a developing epithelial-mesenchymal system--even from dissociated cell preparations--requires an epithelial platform.

  4. Developing the Next Generation of Geoscientists

    NASA Astrophysics Data System (ADS)

    Sparrow, E. B.; Kopplin, M. R.

    2012-12-01

    The Monitoring Seasons Through Global Learning Communities (Seasons and Biomes), an inquiry- and project- based program, works with K-12 teachers and their students worldwide to increase awareness and understanding of the Earth as a system, and the science process. Seasons and Biomes is one of four GLOBE (Global learning and Observations to Benefit the Environment, www.globe.gov) earth system science projects. Seasons and Biomes engage students in ongoing research investigations as way of learning science. We do this by conducting for teachers, professional development workshops that incorporate science content, best teaching practices (that include inquiry, integrating science with math, language and art, authentic assessments, concept mapping), a model for student scientific research, and an earth system science approach. Teachers learn and practice standardized measurement protocols developed by GLOBE in the following areas of investigations: atmosphere, hydrology, soils, phenology and land cover/biology, as well as those developed by Seasons and Biomes on ice seasonality (freeze-up and break-up of rivers and lakes), active layer/depth of soil freezing (frost tube), mosquitoes (larvae abundance and identification of mosquito vectors for malaria and dengue fever) and plant invasive species. They also learn how to enter data as well as access data on the GLOBE website. Teachers in turn teach and work with their students in doing authentic science, contribute data to ongoing research as well as conduct their own studies. During the workshops we also provide guidance and opportunity for early career scientists to share their research, work with teachers and mentor them as well as to develop measurement protocols pertinent to their research. Similarly we work with GLOBE Alumni, students who were in the GLOBE program when they were in primary and/or secondary schools and have graduated from college, yet are still very much inspired and dedicated to working with

  5. Multiple Exciton Generation for Highly Efficient Solar Cells

    NASA Astrophysics Data System (ADS)

    Nozik, Arthur

    2007-03-01

    In order to utilize solar power for the production of electricity and fuel on a massive scale, it will be necessary to develop solar photon conversion systems that have an appropriate combination of high efficiency and low capital cost (/m^2). One new potential approach to high solar cell efficiency is to utilize the unique properties of semiconductor quantum dot nanostructures to control the relaxation dynamics of photogenerated carriers to produce either enhanced photocurrent through efficient multiple exciton generation (MEG) or enhanced photopotential through hot electron transport and transfer processes. To achieve these desirable effects it is necessary to understand and control the dynamics of electron relaxation, cooling, multiple exciton generation , transport, and interfacial electron transfer of the photogenerated carriers with fs to ns time resolution. We have been studying these fundamental dynamics in bulk and nanoscale semiconductors (quantum dots, quantum wires, and quantum wells) using femtosecond transient absorption, photoluminescence, and THz spectroscopy. This work will be summarized and recent advances in creating multiple excitons from a single photon will be discussed, including a unique model to explain efficient MEG based on the coherent superposition of multiple excitonic states. Various possible configurations for quantum dot solar cells that could produce ultra-high conversion efficiencies for the production of electricity, as well as for producing solar fuels (for example, hydrogen from water splitting), will be discussed, along with associated thermodynamic calculations that show the increase in the maximum theoretical gain in solar photon conversion efficiency for both electricity and fuel production.

  6. Development of respiratory rhythm generation in ectothermic vertebrates.

    PubMed

    Hedrick, Michael S

    2005-11-15

    Compared with birds and mammals, very little is known about the development and regulation of respiratory rhythm generation in ectothermic vertebrates. The development and regulation of respiratory rhythm generation in ectothermic vertebrates (fish, amphibians and reptiles) should provide insight into the evolution of these mechanisms. One useful model for examining the development of respiratory rhythm generation in ectothermic vertebrates has emerged from studies with the North American bullfrog (Rana catesbeiana). A major advantage of bullfrogs as a comparative model for respiratory rhythm generation is that respiratory output may be measured at all stages of development, both in vivo and in vitro. An emerging view of recent studies in developing bullfrogs is that many of the mechanisms of respiratory rhythm generation are very similar to those seen in birds and mammals. The overall conclusion from these studies is that respiratory rhythm generation during development may be highly conserved during evolution. The development of respiratory rhythm generation in mammals may, therefore, reflect the antecedent mechanisms seen in ectothermic vertebrates. The main focus of this brief review is to discuss recent data on the development of respiratory rhythm generation in ectothermic vertebrates, with particular emphasis on the North American bullfrog (R. catesbeiana) as a model.

  7. Materials Development for Next Generation Optical Fiber

    PubMed Central

    Ballato, John; Dragic, Peter

    2014-01-01

    Optical fibers, the enablers of the Internet, are being used in an ever more diverse array of applications. Many of the rapidly growing deployments of fibers are in high-power and, particularly, high power-per-unit-bandwidth systems where well-known optical nonlinearities have historically not been especially consequential in limiting overall performance. Today, however, nominally weak effects, most notably stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) are among the principal phenomena restricting continued scaling to higher optical power levels. In order to address these limitations, the optical fiber community has focused dominantly on geometry-related solutions such as large mode area (LMA) designs. Since such scattering, and all other linear and nonlinear optical phenomena including higher order mode instability (HOMI), are fundamentally materials-based in origin, this paper unapologetically advocates material solutions to present and future performance limitations. As such, this paper represents a ‘call to arms’ for material scientists and engineers to engage in this opportunity to drive the future development of optical fibers that address many of the grand engineering challenges of our day. PMID:28788683

  8. High voltage solar cell power generating system

    NASA Technical Reports Server (NTRS)

    Levy, E., Jr.; Opjorden, R. W.; Hoffman, A. C.

    1974-01-01

    A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kW), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2,560 series-connected cells. Each light source consists of twenty 500-watt tungsten iodide lamps providing plus or minus 5 percent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water-cooled plate, a vacuum hold-down system, and air flushing.

  9. Hamiltonian Description of Convective-cell Generation

    SciTech Connect

    J.A. Krommes and R.A. Kolesnikov

    2004-03-11

    The nonlinear statistical growth rate eq for convective cells driven by drift-wave (DW) interactions is studied with the aid of a covariant Hamiltonian formalism for the gyrofluid nonlinearities. A statistical energy theorem is proven that relates eq to a second functional tensor derivative of the DW energy. This generalizes to a wide class of systems of coupled partial differential equations a previous result for scalar dynamics. Applications to (i) electrostatic ion-temperature-gradient-driven modes at small ion temperature, and (ii) weakly electromagnetic collisional DW's are noted.

  10. Successful differentiation to T cells, but unsuccessful B-cell generation, from B-cell-derived induced pluripotent stem cells.

    PubMed

    Wada, Haruka; Kojo, Satoshi; Kusama, Chie; Okamoto, Naoki; Sato, Yorino; Ishizuka, Bunpei; Seino, Ken-ichiro

    2011-01-01

    Forced expression of certain transcription factors in somatic cells results in generation of induced pluripotent stem (iPS) cells, which differentiate into various cell types. We investigated T-cell and B-cell lineage differentiation from iPS cells in vitro. To evaluate the impact of iPS cell source, murine splenic B-cell-derived iPS (B-iPS) cells were generated after retroviral transduction of four transcription factors (Oct4, Sox2, Klf4 and c-Myc). B-iPS cells were identical to embryonic stem (ES) cells and mouse embryonic fibroblast (MEF)-derived iPS cells in morphology, ES cell marker expression as well as teratoma and chimera mouse formation. Both B-iPS and MEF-derived iPS cells differentiated into lymphocytes in OP9 co-culture systems. Both efficiently differentiated into T-cell lineage that produced IFN-γ on T-cell receptor stimulation. However, iPS cells including B-iPS cells were relatively resistant to B-cell lineage differentiation. One of the reasons of the failure of B-cell lineage differentiation seemed due to a defect of Pax5 expression in the differentiated cells. Therefore, current in vitro differentiation systems using iPS cells are sufficient for inducing T-cell but not B-cell lineage.

  11. Collective cell migration in development

    PubMed Central

    Scarpa, Elena

    2016-01-01

    During embryonic development, tissues undergo major rearrangements that lead to germ layer positioning, patterning, and organ morphogenesis. Often these morphogenetic movements are accomplished by the coordinated and cooperative migration of the constituent cells, referred to as collective cell migration. The molecular and biomechanical mechanisms underlying collective migration of developing tissues have been investigated in a variety of models, including border cell migration, tracheal branching, blood vessel sprouting, and the migration of the lateral line primordium, neural crest cells, or head mesendoderm. Here we review recent advances in understanding collective migration in these developmental models, focusing on the interaction between cells and guidance cues presented by the microenvironment and on the role of cell–cell adhesion in mechanical and behavioral coupling of cells within the collective. PMID:26783298

  12. The Human ‘Treg MLR’: Immune Monitoring for Foxp3+ T Regulatory Cell Generation

    PubMed Central

    Levitsky, Josh; Miller, Joshua; Leventhal, Joseph; Huang, Xuemei; Flaa, Cathy; Wang, Edward; Tambur, Anat; Burt, Richard K.; Gallon, Lorenzo; Mathew, James M.

    2009-01-01

    Background Controversy exists about the conditions effecting the development of FOXP3 expressing T cells and their relevance in transplant recipients. Methods We generated CFSE-labeled CD4+CD25highFOXP3+ cells in MLRs (‘the Treg MLR’), with varying HLA disparities and cell components. Five color flow cytometry and 3H TdR uptakes were the readouts. Results 1) Despite lower Stimulation Indices (SI) than 2 DR-mismatched MLRs, 2 DR-matched MLRs generated >2 fold higher percentages when gating on proliferating CD4+CD25highFOXP3+ cells; 2) Even with low numbers of proliferating cells, autologous and HLA identical MLRs generated the highest FOXP3+ : FOXP3- cell ratios; 3) Elimination of either non-CD3+ responding cells (resulting in ‘direct presentation’ only) or responding CD25+ (Treg generating) cells increased the SI but inhibited proliferating CD4+CD25HighFOXP3+ cell development; 4) MLR-generated CD4+CD25HighFOXP3+ cells added as third components specifically inhibited the same freshly set MLR SI and caused recruitment of new CD4+CD25HighFOXP3+ cells. As an example of the ‘Treg MLR’ immune monitoring potential, addition of third component PBMC containing high percentages of CD4+CD25highFOXP3+ cells from an HLA identical kidney transplant recipient (in a tolerance protocol) caused donor-specific Treg MLR inhibition/recruitment. This was similar to the third component MLR Tregs generated entirely in vitro. Conclusion In the ‘Treg MLR’, the generation of CD4+CD25High FOXP3+ cells is more pronounced in the context of self-recognition (HLA matching, indirect presentation). These cells can be assayed for MLR inhibitory and Treg recruitment functions, so as to immunologically monitor allo-specific regulation after transplantation. PMID:19996930

  13. Generation of Gene Knockout Mice by ES Cell Microinjection

    PubMed Central

    Longenecker, Glenn; Kulkarni, Ashok B

    2009-01-01

    This unit lists and describes protocols used in the production of chimeric mice leading to the generation of gene knockout mice. These protocols include the collection of blastocyst embryos, ES cell injection, and uterine transfer of injected blastocysts. Support protocols in the superovulation of blastocyst donor mice, generation of pseudopregnant recipients, fabrication of glass pipettes, and generation of germline mice are also included. Practical tips and solutions are mentioned to help troubleshoot problems that may occur. PMID:19731226

  14. Electrolysis cell functions as water vapor dehumidifier and oxygen generator

    NASA Technical Reports Server (NTRS)

    Clifford, J. E.

    1971-01-01

    Water vapor is absorbed in hygroscopic electrolyte, and oxygen generated by absorbed water electrolysis at anode is added simultaneously to air stream. Cell applications include on-board aircraft oxygen systems, portable oxygen generators, oxygen concentration requirements, and commercial air conditioning and dehumidifying systems.

  15. Generation of diverse neural cell types through direct conversion

    PubMed Central

    Petersen, Gayle F; Strappe, Padraig M

    2016-01-01

    A characteristic of neurological disorders is the loss of critical populations of cells that the body is unable to replace, thus there has been much interest in identifying methods of generating clinically relevant numbers of cells to replace those that have been damaged or lost. The process of neural direct conversion, in which cells of one lineage are converted into cells of a neural lineage without first inducing pluripotency, shows great potential, with evidence of the generation of a range of functional neural cell types both in vitro and in vivo, through viral and non-viral delivery of exogenous factors, as well as chemical induction methods. Induced neural cells have been proposed as an attractive alternative to neural cells derived from embryonic or induced pluripotent stem cells, with prospective roles in the investigation of neurological disorders, including neurodegenerative disease modelling, drug screening, and cellular replacement for regenerative medicine applications, however further investigations into improving the efficacy and safety of these methods need to be performed before neural direct conversion becomes a clinically viable option. In this review, we describe the generation of diverse neural cell types via direct conversion of somatic cells, with comparison against stem cell-based approaches, as well as discussion of their potential research and clinical applications. PMID:26981169

  16. Generation of cardiac pacemaker cells by programming and differentiation.

    PubMed

    Husse, Britta; Franz, Wolfgang-Michael

    2016-07-01

    A number of diseases are caused by faulty function of the cardiac pacemaker and described as "sick sinus syndrome". The medical treatment of sick sinus syndrome with electrical pacemaker implants in the diseased heart includes risks. These problems may be overcome via "biological pacemaker" derived from different adult cardiac cells or pluripotent stem cells. The generation of cardiac pacemaker cells requires the understanding of the pacing automaticity. Two characteristic phenomena the "membrane-clock" and the "Ca(2+)-clock" are responsible for the modulation of the pacemaker activity. Processes in the "membrane-clock" generating the spontaneous pacemaker firing are based on the voltage-sensitive membrane ion channel activity starting with slow diastolic depolarization and discharging in the action potential. The influence of the intracellular Ca(2+) modulating the pacemaker activity is characterized by the "Ca(2+)-clock". The generation of pacemaker cells started with the reprogramming of adult cardiac cells by targeted induction of one pacemaker function like HCN1-4 overexpression and enclosed in an activation of single pacemaker specific transcription factors. Reprogramming of adult cardiac cells with the transcription factor Tbx18 created cardiac cells with characteristic features of cardiac pacemaker cells. Another key transcription factor is Tbx3 specifically expressed in the cardiac conduction system including the sinoatrial node and sufficient for the induction of the cardiac pacemaker gene program. For a successful cell therapeutic practice, the generated cells should have all regulating mechanisms of cardiac pacemaker cells. Otherwise, the generated pacemaker cells serve only as investigating model for the fundamental research or as drug testing model for new antiarrhythmics. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  17. Fuel cells: a survey of current developments

    NASA Astrophysics Data System (ADS)

    Cropper, Mark A. J.; Geiger, Stefan; Jollie, David M.

    Since the first practical uses of fuel cells were developed, it has become clear that they could find use in many products over a wide power range of milliwatts to tens of megawatts. Throughout the 1990s, and later, there has been significant work carried out on adapting the various different fuel cell technologies for use in targetted consumer and industrial applications. This paper discusses these developments and gives details on the specific market segments for providing power to vehicles, portable devices and large- and small-scale stationary power generation.

  18. Distributed Generation to Support Development-Focused Climate Action

    SciTech Connect

    Cox, Sadie; Gagnon, Pieter; Stout, Sherry; Zinaman, Owen; Watson, Andrea; Hotchkiss, Eliza

    2016-09-01

    This paper explores the role of distributed generation, with a high renewable energy contribution, in supporting low emission climate-resilient development. The paper presents potential impacts on development (via energy access), greenhouse gas emission mitigation, and climate resilience directly associated with distributed generation, as well as specific actions that may enhance or increase the likelihood of climate and development benefits. This paper also seeks to provide practical and timely insights to support distributed generation policymaking and planning within the context of common climate and development goals as the distributed generation landscape rapidly evolves globally. Country-specific distributed generation policy and program examples, as well as analytical tools that can inform efforts internationally, are also highlighted throughout the paper.

  19. [Development of blood cell measurement].

    PubMed

    Okada, T

    2000-10-01

    Automated blood cell analyzers used in hematology laboratories are required to measure many specimens rapidly and efficiency has been realized through increasing the measurement parameters and throughput volume in one instrument. In the period of 1950's through the early part of 1960's, only red blood cells and white blood cells could be counted. In 1965, Technicon Corporation developed an instrument which can measure the number of blood cells, hemoglobin, hematocrit and calculate corpuscular constants simultaneously. Thereafter, the methodologies for simultaneous platelet measurement and precise determination of blood cell distribution have been developed. Then, the development of new reagents has achieved three part differentials in the distribution of white blood cells. Thanks to this development, microscopic white blood cell differentials has been replaced by blood cell analyzers in screening tests. Though blood cell analyzers may be further improved by expanding of the number of parameters available for simultaneous measurements, meeting social needs in the new era will not be possible without the creation and realization of new concepts employing new technologies such as IT (Information Technology).

  20. Duration of red blood cell storage and inflammatory marker generation

    PubMed Central

    Sut, Caroline; Tariket, Sofiane; Chou, Ming Li; Garraud, Olivier; Laradi, Sandrine; Hamzeh-Cognasse, Hind; Seghatchian, Jerard; Burnouf, Thierry; Cognasse, Fabrice

    2017-01-01

    Red blood cell (RBC) transfusion is a life-saving treatment for several pathologies. RBCs for transfusion are stored refrigerated in a preservative solution, which extends their shelf-life for up to 42 days. During storage, the RBCs endure abundant physicochemical changes, named RBC storage lesions, which affect the overall quality standard, the functional integrity and in vivo survival of the transfused RBCs. Some of the changes occurring in the early stages of the storage period (for approximately two weeks) are reversible but become irreversible later on as the storage is extended. In this review, we aim to decipher the duration of RBC storage and inflammatory marker generation. This phenomenon is included as one of the causes of transfusion-related immunomodulation (TRIM), an emerging concept developed to potentially elucidate numerous clinical observations that suggest that RBC transfusion is associated with increased inflammatory events or effects with clinical consequence. PMID:28263172

  1. Cellular interactions via conditioned media induce in vivo nephron generation from tubular epithelial cells or mesenchymal stem cells

    SciTech Connect

    Machiguchi, Toshihiko Nakamura, Tatsuo

    2013-06-07

    Highlights: •We have attempted in vivo nephron generation using conditioned media. •Vascular and tubular cells do cross-talks on cell proliferation and tubular changes. •Tubular cells suppress these changes in mesenchymal stem cells. •Tubular cells differentiate mesenchymal stem cells into tubular cells. •Nephrons can be created from implanted tubular cells or mesenchymal stem cells. -- Abstract: There are some successful reports of kidney generation by utilizing the natural course of kidney development, namely, the use of an artificially treated metanephros, blastocyst or ureteric bud. Under a novel concept of cellular interactions via conditioned media (CMs), we have attempted in vivo nephron generation from tubular epithelial cells (TECs) or mesenchymal stem cells (MSCs). Here we used 10× CMs of vascular endothelial cells (VECs) and TECs, which is the first to introduce a CM into the field of organ regeneration. We first present stimulative cross-talks induced by these CMs between VECs and TECs on cell proliferation and morphological changes. In MSCs, TEC-CM suppressed these changes, however, induced cytokeratin expression, indicating the differentiation of MSCs into TECs. As a result, glomerular and tubular structures were created following the implantation of TECs or MSCs with both CMs. Our findings suggest that the cellular interactions via CMs might induce in vivo nephron generation from TECs or MSCs. As a promoting factor, CMs could also be applied to the regeneration of other organs and tissues.

  2. Teaching Generation Text: Using Cell Phones to Enhance Learning

    ERIC Educational Resources Information Center

    Nielsen, Lisa; Webb, Willyn

    2011-01-01

    "Teaching Generation Text" shows how teachers can turn cell phones into an educational opportunity instead of an annoying distraction. With a host of innovative ideas, activities, lessons, and strategies, Nielsen and Webb offer a unique way to use students' preferred method of communication in the classroom. Cell phones can remind students to…

  3. Teaching Generation Text: Using Cell Phones to Enhance Learning

    ERIC Educational Resources Information Center

    Nielsen, Lisa; Webb, Willyn

    2011-01-01

    "Teaching Generation Text" shows how teachers can turn cell phones into an educational opportunity instead of an annoying distraction. With a host of innovative ideas, activities, lessons, and strategies, Nielsen and Webb offer a unique way to use students' preferred method of communication in the classroom. Cell phones can remind students to…

  4. Compost in plant microbial fuel cell for bioelectricity generation.

    PubMed

    Moqsud, M A; Yoshitake, J; Bushra, Q S; Hyodo, M; Omine, K; Strik, David

    2015-02-01

    Recycling of organic waste is an important topic in developing countries as well as developed countries. Compost from organic waste has been used for soil conditioner. In this study, an experiment has been carried out to produce green energy (bioelectricity) by using paddy plant microbial fuel cells (PMFCs) in soil mixed with compost. A total of six buckets filled with the same soil were used with carbon fiber as the electrodes for the test. Rice plants were planted in five of the buckets, with the sixth bucket containing only soil and an external resistance of 100 ohm was used for all cases. It was observed that the cells with rice plants and compost showed higher values of voltage and power density with time. The highest value of voltage showed around 700 mV when a rice plant with 1% compost mixed soil was used, however it was more than 95% less in the case of no rice plant and without compost. Comparing cases with and without compost but with the same number of rice plants, cases with compost depicted higher voltage to as much as 2 times. The power density was also 3 times higher when the compost was used in the paddy PMFCs which indicated the influence of compost on bio-electricity generation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Fuel cell development for transportation: Catalyst development

    SciTech Connect

    Doddapaneni, N.; Ingersoll, D.

    1996-12-31

    Fuel cells are being considered as alternative power sources for transportation and stationary applications. The degradation of commonly used electrode catalysts (e.g. Pt, Ag, and others) and corrosion of carbon substrates are making commercialization of fuel cells incorporating present day technologies economically problematic. Furthermore, due to the instability of the Pt catalyst, the performance of fuel cells declines on long-term operation. When methanol is used as the fuel, a voltage drop, as well as significant thermal management problems can be encountered, the later being due to chemical oxidation of methanol at the platinized carbon at the cathode. Though extensive work was conducted on platinized electrodes for both the oxidation and reduction reactions, due to the problems mentioned above, fuel cells have not been fully developed for widespread commercial use. Several investigators have previously evaluated metal macrocyclic complexes as alternative catalysts to Pt and Pt/Ru in fuel cells. Unfortunately, though they have demonstrated catalytic activity, these materials were found to be unstable on long term use in the fuel cell environment. In order to improve the long-term stability of metal macrocyclic complexes, we have chemically bonded these complexes to the carbon substrate, thereby enhancing their catalytic activity as well as their chemical stability in the fuel cell environment. We have designed, synthesized, and evaluated these catalysts for O{sub 2} reduction, H{sub 2} oxidation, and direct methanol oxidation in Proton Exchange Membrane (PEM) and aqueous carbonate fuel cells. These catalysts exhibited good catalytic activity and long-term stability. In this paper we confine our discussion to the initial performance results of some of these catalysts in H{sub 2}/O{sub 2} PEM fuel cells, including their long-term performance characteristics as well as CO poisoning effects on these catalysts.

  6. Development of a Team Scenario Content Generation Framework

    DTIC Science & Technology

    2010-03-01

    Development of a Team Scenario Content Generation Framework Andrew Morton Barbara D. Adams Project Manager: Barbara D. Adams Contract No. W7711... GENERATION FRAMEWORK by: Andrew Morton and Barbara D. Adams Humansystems® Incorporated 111 Farquhar Street Guelph, ON N1H 3N4 Project... Generation Framework Page i Abstract Web-based software called ELICIT (Experimental Laboratory for the Investigation of Collaboration, Information-sharing

  7. Generation of human pluripotent stem cell-derived hepatocyte-like cells for drug toxicity screening.

    PubMed

    Takayama, Kazuo; Mizuguchi, Hiroyuki

    2017-02-01

    Because drug-induced liver injury is one of the main reasons for drug development failures, it is important to perform drug toxicity screening in the early phase of pharmaceutical development. Currently, primary human hepatocytes are most widely used for the prediction of drug-induced liver injury. However, the sources of primary human hepatocytes are limited, making it difficult to supply the abundant quantities required for large-scale drug toxicity screening. Therefore, there is an urgent need for a novel unlimited, efficient, inexpensive, and predictive model which can be applied for large-scale drug toxicity screening. Human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are able to replicate indefinitely and differentiate into most of the body's cell types, including hepatocytes. It is expected that hepatocyte-like cells generated from human ES/iPS cells (human ES/iPS-HLCs) will be a useful tool for drug toxicity screening. To apply human ES/iPS-HLCs to various applications including drug toxicity screening, homogenous and functional HLCs must be differentiated from human ES/iPS cells. In this review, we will introduce the current status of hepatocyte differentiation technology from human ES/iPS cells and a novel method to predict drug-induced liver injury using human ES/iPS-HLCs.

  8. Generation of cellular immune memory and B-cell immunity is impaired by natural killer cells.

    PubMed

    Rydyznski, Carolyn; Daniels, Keith A; Karmele, Erik P; Brooks, Taylor R; Mahl, Sarah E; Moran, Michael T; Li, Caimei; Sutiwisesak, Rujapak; Welsh, Raymond M; Waggoner, Stephen N

    2015-02-27

    The goal of most vaccines is the induction of long-lived memory T and B cells capable of protecting the host from infection by cytotoxic mechanisms, cytokines and high-affinity antibodies. However, efforts to develop vaccines against major human pathogens such as HIV and HCV have not been successful, thereby highlighting the need for novel approaches to circumvent immunoregulatory mechanisms that limit the induction of protective immunity. Here, we show that mouse natural killer (NK) cells inhibit generation of long-lived virus-specific memory T- and B cells as well as virus-specific antibody production after acute infection. Mechanistically, NK cells suppressed CD4 T cells and follicular helper T cells (T(FH)) in a perforin-dependent manner during the first few days of infection, resulting in a weaker germinal centre (GC) response and diminished immune memory. We anticipate that innovative strategies to relieve NK cell-mediated suppression of immunity should facilitate development of efficacious new vaccines targeting difficult-to-prevent infections.

  9. Generation of Multipotent Foregut Stem Cells from Human Pluripotent Stem Cells

    PubMed Central

    Hannan, Nicholas R.F.; Fordham, Robert P.; Syed, Yasir A.; Moignard, Victoria; Berry, Andrew; Bautista, Ruben; Hanley, Neil A.; Jensen, Kim B.; Vallier, Ludovic

    2013-01-01

    Summary Human pluripotent stem cells (hPSCs) could provide an infinite source of clinically relevant cells with potential applications in regenerative medicine. However, hPSC lines vary in their capacity to generate specialized cells, and the development of universal protocols for the production of tissue-specific cells remains a major challenge. Here, we have addressed this limitation for the endodermal lineage by developing a defined culture system to expand and differentiate human foregut stem cells (hFSCs) derived from hPSCs. hFSCs can self-renew while maintaining their capacity to differentiate into pancreatic and hepatic cells. Furthermore, near-homogenous populations of hFSCs can be obtained from hPSC lines which are normally refractory to endodermal differentiation. Therefore, hFSCs provide a unique approach to bypass variability between pluripotent lines in order to obtain a sustainable source of multipotent endoderm stem cells for basic studies and to produce a diversity of endodermal derivatives with a clinical value. PMID:24319665

  10. In utero development of memory T cells.

    PubMed

    Zhivaki, Dania; Lo-Man, Richard

    2017-09-12

    Pathogen-specific immune memory develops subsequent to primary exposure to antigen, mainly in the context of infection or vaccination to provide protection. Although a safe fetal life requires a tolerogenic environment in order to circumvent unnecessary inflammatory responses, it needs to be prepared in utero to face the microbial environment outside the womb. The possibility of immune memory generation in the fetus would help such transition providing protection in early life. This requires fetal T cell exposure to foreign antigens presented by dendritic cells. There are evidences of fetal T cell priming in several cases of congenital infections or in uninfected children born of infected mothers. Fetal T cell memory seems to arise also without any reported infection during pregnancy. Such memory T cells display various effector functions, including Th1, Th2, or Th17 profiles, raising the issue of benefits and risks for postnatal life when considering maternal vaccination, susceptibility to infection, or environmental allergen sensitization.

  11. Development and Test of a Prototype 100MVA Superconducting Generator

    SciTech Connect

    Fogarty, James M.; Bray, James W.

    2007-05-25

    In 2002, General Electric and the US Department of Energy (DOE) entered into a cooperative agreement for the development of a commercialized 100 MVA generator using high temperature superconductors (HTS) in the field winding. The intent of the program was to: • Identify and develop technologies that would be needed for such a generator. • Develop conceptual designs for generators with ratings of 100 MVA and higher using HTS technology. • Perform proof of concept tests at the 1.5 MW level for GE’s proprietary warm iron rotor HTS generator concept. • Design, build, and test a prototype of a commercially viable 100 MVA generator that could be placed on the power grid. This report summarizes work performed during the program and is provided as one of the final program deliverables.

  12. The Multidimensional Nursing Generations Questionnaire: development, reliability, and validity assessments.

    PubMed

    Stevanin, Simone; Bressan, Valentina; Vehviläinen-Julkunen, Katri; Pagani, Laura; Poletti, Piera; Kvist, Tarja

    2017-05-01

    To develop and perform reliability and validity assessments of the international Multidimensional Nursing Generations Questionnaire. There are three generations of nurses in the European workforce. There is little research on the characteristics of these generations and the ways in which to manage them professionally, and no instrument has yet been developed to measure these aspects specifically. With results from previous studies, 69 nursing generations-oriented items were created in English, translated into Italian and Finnish, and pretested to form the basis of an instrument that was tested between September and October 2014 on a sample of Finnish and Italian nurses (n = 1302) using principal component analysis and Cronbach's alpha. Fifty-four items and eight components (Cronbach's α range: 0.61-0.81) were identified in the instrument: (1) conflicts between generations; (2) patient safety view; (3) relationships between generations; (4) working as a multigenerational team; (5) orientation to change; (6) presenteeism and job propensity; (7) intention to leave, and (8) flexibility and availability. The instrument showed acceptable preliminary psychometric properties and satisfactory internal consistency. The Multidimensional Nursing Generations Questionnaire is a useful tool to measure the characteristics of different generations of nurses and to develop management strategies tailored to those generations. © 2017 John Wiley & Sons Ltd.

  13. Developments and trends in three-dimensional mesh generation

    NASA Technical Reports Server (NTRS)

    Baker, Timothy J.

    1989-01-01

    An intense research effort over the last few years has produced several competing and apparently diverse methods for generating meshes. Recent progress is reviewed and the central themes are emphasized which form a solid foundation for future developments in mesh generation.

  14. Next Generation Bipolar Plates for Automotive PEM Fuel Cells

    SciTech Connect

    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

  15. Mouse differentiating spermatogonia can generate germinal stem cells in vivo.

    PubMed

    Barroca, Vilma; Lassalle, Bruno; Coureuil, Mathieu; Louis, Jean Paul; Le Page, Florence; Testart, Jacques; Allemand, Isabelle; Riou, Lydia; Fouchet, Pierre

    2009-02-01

    In adults, stem cells are responsible for the maintenance of many actively renewing tissues, such as haematopoietic, skin, gut and germinal tissues. These stem cells can self-renew or be committed to becoming progenitors. Stem-cell commitment is thought to be irreversible but in male and female Drosophila melanogaster, it was shown recently that differentiating germ cells can revert to functional stem cells that can restore germinal lineage. Whether progenitors are also able to generate stem cells in mammals remains unknown. Here we show that purified mouse spermatogonial progenitors committed to differentiation can generate functional germinal stem cells that can repopulate germ-cell-depleted testes when transplanted into adult mice. We found that GDNF, a key regulator of the stem-cell niche, and FGF2 are able to reprogram in vitro spermatogonial progenitors for reverse differentiation. This study supports the emerging concept that the stem-cell identity is not restricted in adults to a definite pool of cells that self-renew, but that stemness could be acquired by differentiating progenitors after tissue injury and throughout life.

  16. Fusion of human bone hemopoietic stem cell with esophageal carcinoma cells didn't generate esophageal cancer stem cell.

    PubMed

    Fan, H; Lu, S

    2014-01-01

    Prior studies showed that cell fusion between bone marrow-derived cell (BMDC) and somatic cell might be the origin of cancer stem cell. Our previous study suggested that cell fusion of human bone marrow-derived mesenchymal stem cell (MSC) with esophageal cancer cell did not generate cancer stem cells. But up to now, the origin of cancer stem cell is still ambiguous. In this study, we carried out the cell fusion experiment between hemopoietic stem cells (HSCs) and human esophageal cancer cells, and found that cell fusion slowed the growth speed of esophageal cancer cells and decreased the clone formation ability and tumorigenicity in NOD/SCID mice. In addition, cell fusion did not increase the ratio of side population (SP) cells and the resistance to chemotherapeutic drugs. Collectively, our data indicated that cell fusion between HSCs and esophageal cancer cells has a therapeutic effect rather than generate cells with characteristics of esophageal cancer stem cells.

  17. Hesr1 and Hesr3 are essential to generate undifferentiated quiescent satellite cells and to maintain satellite cell numbers.

    PubMed

    Fukada, So-ichiro; Yamaguchi, Masahiko; Kokubo, Hiroki; Ogawa, Ryo; Uezumi, Akiyoshi; Yoneda, Tomohiro; Matev, Miroslav M; Motohashi, Norio; Ito, Takahito; Zolkiewska, Anna; Johnson, Randy L; Saga, Yumiko; Miyagoe-Suzuki, Yuko; Tsujikawa, Kazutake; Takeda, Shin'ichi; Yamamoto, Hiroshi

    2011-11-01

    Satellite cells, which are skeletal muscle stem cells, divide to provide new myonuclei to growing muscle fibers during postnatal development, and then are maintained in an undifferentiated quiescent state in adult skeletal muscle. This state is considered to be essential for the maintenance of satellite cells, but their molecular regulation is unknown. We show that Hesr1 (Hey1) and Hesr3 (Heyl) (which are known Notch target genes) are expressed simultaneously in skeletal muscle only in satellite cells. In Hesr1 and Hesr3 single-knockout mice, no obvious abnormalities of satellite cells or muscle regenerative potentials are observed. However, the generation of undifferentiated quiescent satellite cells is impaired during postnatal development in Hesr1/3 double-knockout mice. As a result, myogenic (MyoD and myogenin) and proliferative (Ki67) proteins are expressed in adult satellite cells. Consistent with the in vivo results, Hesr1/3-null myoblasts generate very few Pax7(+) MyoD(-) undifferentiated cells in vitro. Furthermore, the satellite cell number gradually decreases in Hesr1/3 double-knockout mice even after it has stabilized in control mice, and an age-dependent regeneration defect is observed. In vivo results suggest that premature differentiation, but not cell death, is the reason for the reduced number of satellite cells in Hesr1/3 double-knockout mice. These results indicate that Hesr1 and Hesr3 are essential for the generation of adult satellite cells and for the maintenance of skeletal muscle homeostasis.

  18. Generation of induced pluripotent stem cells with high efficiency from human embryonic renal cortical cells

    PubMed Central

    Yao, Ling; Chen, Ruifang; Wang, Pu; Zhang, Qi; Tang, Hailiang; Sun, Huaping

    2016-01-01

    Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) emerges as a prospective therapeutic angle in regenerative medicine and a tool for drug screening. Although increasing numbers of iPSCs from different sources have been generated, there has been limited progress in yield of iPSC. Here, we show that four Yamanaka factors Oct4, Sox2, Klf4 and c-Myc can convert human embryonic renal cortical cells (hERCCs) to pluripotent stem cells with a roughly 40-fold higher reprogramming efficiency compared with that of adult human dermal fibroblasts. These iPSCs show pluripotency in vitro and in vivo, as evidenced by expression of pluripotency associated genes, differentiation into three embryonic germ layers by teratoma tests, as well as neuronal fate specification by embryoid body formation. Moreover, the four exogenous genes are effectively silenced in these iPSCs. This study highlights the use of hERCCs to generate highly functional human iPSCs which may aid the study of genetic kidney diseases and accelerate the development of cell-based regenerative therapy. PMID:27904699

  19. Dynamics of Cell Generation and Turnover in the Human Heart.

    PubMed

    Bergmann, Olaf; Zdunek, Sofia; Felker, Anastasia; Salehpour, Mehran; Alkass, Kanar; Bernard, Samuel; Sjostrom, Staffan L; Szewczykowska, Mirosława; Jackowska, Teresa; Dos Remedios, Cris; Malm, Torsten; Andrä, Michaela; Jashari, Ramadan; Nyengaard, Jens R; Possnert, Göran; Jovinge, Stefan; Druid, Henrik; Frisén, Jonas

    2015-06-18

    The contribution of cell generation to physiological heart growth and maintenance in humans has been difficult to establish and has remained controversial. We report that the full complement of cardiomyocytes is established perinataly and remains stable over the human lifespan, whereas the numbers of both endothelial and mesenchymal cells increase substantially from birth to early adulthood. Analysis of the integration of nuclear bomb test-derived (14)C revealed a high turnover rate of endothelial cells throughout life (>15% per year) and more limited renewal of mesenchymal cells (<4% per year in adulthood). Cardiomyocyte exchange is highest in early childhood and decreases gradually throughout life to <1% per year in adulthood, with similar turnover rates in the major subdivisions of the myocardium. We provide an integrated model of cell generation and turnover in the human heart.

  20. ARPA advanced fuel cell development

    SciTech Connect

    Dubois, L.H.

    1995-08-01

    Fuel cell technology is currently being developed at the Advanced Research Projects Agency (ARPA) for several Department of Defense applications where its inherent advantages such as environmental compatibility, high efficiency, and low noise and vibration are overwhelmingly important. These applications range from man-portable power systems of only a few watts output (e.g., for microclimate cooling and as direct battery replacements) to multimegawatt fixed base systems. The ultimate goal of the ARPA program is to develop an efficient, low-temperature fuel cell power system that operates directly on a military logistics fuel (e.g., DF-2 or JP-8). The absence of a fuel reformer will reduce the size, weight, cost, and complexity of such a unit as well as increase its reliability. In order to reach this goal, ARPA is taking a two-fold, intermediate time-frame approach to: (1) develop a viable, low-temperature proton exchange membrane (PEM) fuel cell that operates directly on a simple hydrocarbon fuel (e.g., methanol or trimethoxymethane) and (2) demonstrate a thermally integrated fuel processor/fuel cell power system operating on a military logistics fuel. This latter program involves solid oxide (SOFC), molten carbonate (MCFC), and phosphoric acid (PAFC) fuel cell technologies and concentrates on the development of efficient fuel processors, impurity scrubbers, and systems integration. A complementary program to develop high performance, light weight H{sub 2}/air PEM and SOFC fuel cell stacks is also underway. Several recent successes of these programs will be highlighted.

  1. Generation of development environments for the Arden Syntax.

    PubMed Central

    Bång, M.; Eriksson, H.

    1997-01-01

    Providing appropriate development environments for specialized languages requires a significant development and maintenance effort. Specialized environments are therefore expensive when compared to their general-language counterparts. The Arden Syntax for Medical Logic Modules (MLM) is a standardized language for representing medical knowledge. We have used PROTEGE-II, a knowledge-engineering environment, to generate a number of experimental development environments for the Arden Syntax. MEDAILLE is the resulting MLM editor, which provides a user-friendly environment that allows users to create and modify MLM definitions. Although MEDAILLE is a generated editor, it has similar functionality, while reducing the programming effort, as compared to other MLM editors developed using traditional programming techniques. We discuss how developers can use PROTEGE-II to generate development environments for other standardized languages and for general programming languages. PMID:9357639

  2. Immunologic considerations for generating memory CD8 T cells through vaccination.

    PubMed

    Butler, Noah S; Nolz, Jeffrey C; Harty, John T

    2011-07-01

    Following infection or vaccination, naïve CD8 T cells that receive the appropriate integration of antigenic, co-stimulatory and inflammatory signals undergo a programmed series of biological changes that ultimately results in the generation of memory cells. Memory CD8 T cells, in contrast to naïve cells, more effectively limit or prevent pathogen re-infection because of both qualitative and quantitative changes that occur following their induction. Unlike vaccination strategies aimed at generating antibody production, the ability to generate protective memory CD8 T cells has proven more complicated and problematic. However, recent experimental results have revealed important principles regarding the molecular and genetic basis for memory CD8 T cell formation, as well as identified ways to manipulate their development through vaccination, resulting in potential new avenues to enhance protective immunity. © 2011 Blackwell Publishing Ltd.

  3. T cells generated in the absence of a thoracic thymus fail to establish homeostasis.

    PubMed

    Smolarchuk, Christa; Zhu, Lin Fu; Chan, William F N; Anderson, Colin C

    2014-08-01

    Cervical thymus mimics the thoracic thymus in supporting T-cell development and exists in a subset of mice and humans. Importantly, it remains unknown whether the cervical thymus can generate T cells that are self-tolerant in the complete absence of signals from the thoracic thymus. Using a fetal liver reconstitution model in thoracic thymectomized RAG(-/-) mice, we found that T cells could be generated without contribution from the thoracic thymus. However, these mice had decreased T cells, increased proportions of effector memory T cells and Treg phenotype cells, increased serum IgG1/2b, and increased frequency of T cells expressing IFN-γ, IL-17 or IL-10. Half of the mice that received a thoracic thymectomy and fetal liver cells, unlike sham surgery controls, developed substantial morbidity with age. Disease was associated with lymphopenia-driven activation rather than inherent defects in the cervical thymus, as both thoracic and cervical thymocytes could generate disease in lymphopenic recipients. Administration of the homeostatic cytokine IL-7 caused a rapid, transient increase in T-cell numbers and reduced the time to disease onset. Together the data suggests that the cervical thymus can function in the complete absence of the thoracic thymus; however, the T cells generated do not establish homeostasis.

  4. High-Temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

    2004-01-01

    The vast majority of satellites and near-earth probes developed to date have relied upon photovoltaic power generation. If future missions to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. For example, the equilibrium temperature of a Mercury surface station will be about 450 C, and the temperature of solar arrays on the proposed "Solar Probe" mission will extend to temperatures as high as 2000 C (although it is likely that the craft will operate on stored power rather than solar energy during the closest approach to the sun). Advanced thermal design principles, such as replacing some of the solar array area with reflectors, off-pointing, and designing the cells to reflect rather than absorb light out of the band of peak response, can reduce these operating temperature somewhat. Nevertheless, it is desirable to develop approaches to high-temperature solar cell design that can operate under temperature extremes far greater than today's cells. Solar cells made from wide bandgap (WBG) compound semiconductors are an obvious choice for such an application. In order to aid in the experimental development of such solar cells, we have initiated a program studying the theoretical and experimental photovoltaic performance of wide bandgap materials. In particular, we have been investigating the use of GaP, SiC, and GaN materials for space solar cells. We will present theoretical results on the limitations on current cell technologies and the photovoltaic performance of these wide-bandgap solar cells in a variety of space conditions. We will also give an overview of some of NASA's cell developmental efforts in this area and discuss possible future mission applications.

  5. Indomethacin augments lymphokine-activated killer cell generation by patients with malignant mesothelioma

    SciTech Connect

    Manning, L.S.; Bowman, R.V.; Davis, M.R.; Musk, A.W.; Robinson, B.W. )

    1989-10-01

    Human malignant mesothelioma (MM) cells are resistant to natural killer (NK) cell lysis but susceptible to lysis by lymphokine-activated killer (LAK) cells from control individuals. The present study was performed to determine the capacity of patients with MM (n = 22) and individuals occupationally exposed to asbestos (the major population at risk of developing this disease, n = 52) to generate LAK cells capable of effectively lysing human mesothelioma cells. Compared to controls (n = 20), both patient groups demonstrated significantly depressed LAK cell activity against mesothelioma tumor cell targets (55 +/- 3% lysis by controls vs 34 +/- 3% lysis by patients with MM, P less than 0.005; and 45 +/- 3% lysis by asbestos-exposed individuals, P less than 0.025). Addition of 10 micrograms/ml indomethacin during LAK cell generation restored normal LAK cell activity for patients with MM (52 +/- 6% lysis of cultured human MM cells, P = NS compared to controls), suggesting that the defective cytolytic cell function observed in some patients with MM is a result of prostaglandin-induced immunosuppression. The ability of indomethacin to restore suppressed LAK cell activity in patients with MM suggests that the concomitant use of this agent in ex vivo LAK cell generation and in patients undergoing interleukin/LAK cell therapy may be beneficial.

  6. Functional imaging of muscle cells by second harmonic generation

    NASA Astrophysics Data System (ADS)

    Nucciotti, Valentina; Sacconi, Leonardo; Linari, Marco; Lombardi, Vincenzo; Piazzesi, Gabriella; Piroddi, Nicoletta; Poggesi, Corrado; Tesi, Chiara; Vanzi, Francesco; Pavone, Francesco S.

    2006-02-01

    The intrinsically ordered arrays of proteins (mainly actin and myosin) constituting the myofibrils within muscle cells are at the basis of a strong Second Harmonic Generation (SHG) from muscle fibers and isolated myofibrils. We have characterized the SHG signal with regard to its polarization and potential source within the muscle cell. The lateral resolution that can be achieved through SHG imaging of muscle strongly depends on sample depth. In fact, a comparison between intact muscle fibers and single myofibrils demonstrates that, whereas in both cases the alternation of dark I bands and bright A bands is visible, the contours of these bands are much better resolved in myofibrils than in fibers. Further, imaging of myofibrils revealed the presence of a darker zone in the centre of the A band. These effects of scattering by tissue on the image resolution were also studied with regard to the polarization of the SHG signal. The polarization-dependence of SHG intensity represents a powerful tool for the investigation of the structural dynamics occurring in the emitting proteins during the active cycle of muscle contraction. The prospective to perform functional studies requires a complete characterization of the effects of scattering and possibly multiple emitting populations on the measured SHG signal. Also, SHG is extremely sensitive to the degree of order present in the filament array, offering an interesting potential in the development of non-invasive tools for the diagnosis of degenerative diseases affecting skeletal muscles.

  7. Generating kidney organoids from human pluripotent stem cells

    PubMed Central

    Takasato, Minoru; Er, Pei X; Chiu, Han S; Little, Melissa H

    2016-01-01

    The human kidney develops from four progenitor populations; nephron progenitors, ureteric epithelial progenitors, renal interstitial progenitors and endothelial progenitors; resulting in the formation of maximally 2 million nephrons. Until recently, methods differentiating human pluripotent stem cells (hPSCs) into either nephron progenitor or ureteric epithelial progenitor had been reported, consequently forming only nephrons or collecting ducts, respectively. Here, we detail a protocol that simultaneously induces all four progenitors to generate kidney organoids within which segmented nephrons are connected to collecting ducts and surrounded by renal interstitial cells and an endothelial network. As evidence of functional maturity, proximal tubules within organoids display megalin-mediated and cubilin-mediated endocytosis, and respond to a nephrotoxicant to undergo apoptosis. This protocol consists of 7 days of monolayer culture for intermediate mesoderm induction followed by 18 days of three-dimensional culture to facilitate self-organising renogenic events leading to organoid formation. Personnel experienced in culturing hPSCs are required to conduct this protocol. PMID:27560173

  8. Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations

    PubMed Central

    Swelstad, Brad B; Kerr, Candace L

    2010-01-01

    Pluripotent stem cells have been derived from various embryonic, fetal and adult sources. Embryonic stem cells (ESCs) and parthenogenic ESCs (pESCs) are derived from the embryo proper while embryonic germ cells (EGCs), embryonal carcinoma cells (ECCs), and germ-line stem cells (GSC) are produced from germ cells. ECCs were the first pluripotent stem cell lines established from adult testicular tumors while EGCs are generated in vitro from primordial germ cells (PGCs) isolated in late embryonic development. More recently, studies have also demonstrated the ability to produce GSCs from adult germ cells, known as spermatogonial stem cells. Unlike ECCs, the source of GSCs are normal, non-cancerous adult tissue. The study of these unique cell lines has provided information that has led to the ability to reprogram somatic cells into an ESC-like state. These cells, called induced pluripotent stem cells (iPSCs), have been derived from a number of human fetal and adult origins. With the promises pluripotent stem cells bring to cell-based therapies there remain several considerations that need to be carefully studied prior to their clinical use. Many of these issues involve understanding key factors regulating their generation, including those which define pluripotency. In this regard, the following article discusses critical aspects of pluripotent stem cell derivation and current issues about their therapeutic potential. PMID:24198508

  9. Generation of Human Corneal Endothelial Cells via In Vitro Ocular Lineage Restriction of Pluripotent Stem Cells

    PubMed Central

    Zhao, Jiagang J.; Afshari, Natalie A.

    2016-01-01

    Purpose We generate a renewable supply of corneal endothelial cells (CEC) from human pluripotent stem cells (PSCs) under defined culture conditions. Methods Corneal endothelial cell induction was driven by small molecules in a stepwise fashion of lineage specification. During the initial phase, PSC fate was restricted to the eye field-like state and became eye field stem cells (EFSCs). In the second phase, PSC-derived EFSCs were further directed toward either neural crest lineage or retinal lineage. The CECs were directly induced from ocular neural crest stem cells (NCSCs) by suppressing TGF-β and ROCK signaling. Results Under chemically defined conditions, PSCs were massively converted into EFSCs and subsequently NCSCs. Eye field cell identity was characterized by the expression of key fate restriction factors for early eye field cells, such as PAX6, LHX2, and VSX2. The induction of ocular NCSCs was initiated by promoting WNT signaling in EFSCs. Within 2 weeks of induction, the majority of cells expressed the typical neural crest markers p75NTR and HNK-1. Eye field stem cell-derived NCSCs can be propagated and cryopreserved. Subsequently, a CEC monolayer was induced from adherent NCSCs in the presence of small molecular inhibitors to suppress TGF-β and ROCK signaling. The polygon-shaped CEC-like cells became visible after a week in culture. The NCSC-derived CECs expressed typical CEC markers, such as N-Cadherin and Na+/K+-ATPase. Conclusions A novel small molecule-based approach was developed to derive human CECs from PSCs via ocular lineage specification. Moreover, EFSC-derived NCSCs could serve as an immediate source cell for rapid CEC induction in vitro. PMID:28002562

  10. Neural stem cells: generating and regenerating the brain.

    PubMed

    Gage, Fred H; Temple, Sally

    2013-10-30

    One of the landmark events of the past 25 years in neuroscience research was the establishment of neural stem cells (NSCs) as a life-long source of neurons and glia, a concept that shattered the dogma that the nervous system lacked regenerative power. Stem cells afford the plasticity to generate, repair, and change nervous system function. Combined with reprogramming technology, human somatic cell-derived NSCs and their progeny can model neurological diseases with improved accuracy. As technology advances, we anticipate further important discoveries and novel therapies based on the knowledge and application of these powerful cells.

  11. Generating pluripotent stem cells: differential epigenetic changes during cellular reprogramming.

    PubMed

    Tobin, Stacey C; Kim, Kitai

    2012-08-31

    Pluripotent stem cells hold enomous potential for therapuetic applications in tissue replacement therapy. Reprogramming somatic cells from a patient donor to generate pluripotent stem cells involves both ethical concerns inherent in the use of embryonic and oocyte-derived stem cells, as well as issues of histocompatibility. Among the various pluripotent stem cells, induced pluripotent stem cells (iPSC)--derived by ectopic expression of four reprogramming factors in donor somatic cells--are superior in terms of ethical use, histocompatibility, and derivation method. However, iPSC also show genetic and epigenetic differences that limit their differentiation potential, functionality, safety, and potential clinical utility. Here, we discuss the unique characteristics of iPSC and approaches that are being taken to overcome these limitations.

  12. Lithium-Air Cell Development

    NASA Technical Reports Server (NTRS)

    Reid, Concha M.; Dobley, Arthur; Seymour, Frasier W.

    2014-01-01

    Lithium-air (Li-air) primary batteries have a theoretical specific capacity of 11,400 Wh/kg, the highest of any common metal-air system. NASA is developing Li-air technology for a Mobile Oxygen Concentrator for Spacecraft Emergencies, an application which requires an extremely lightweight primary battery that can discharge over 24 hours continuously. Several vendors were funded through the NASA SBIR program to develop Li-air technology to fulfill the requirements of this application. New catalysts and carbon cathode structures were developed to enhance the oxygen reduction reaction and increase surface area to improve cell performance. Techniques to stabilize the lithium metal anode surface were explored. Experimental results for prototype laboratory cells are given. Projections are made for the performance of hypothetical cells constructed from the materials that were developed.

  13. Generating Aptamers for Recognition of Virus-Infected Cells

    PubMed Central

    Tang, Zhiwen; Parekh, Parag; Turner, Pete; Moyer, Richard W.; Tan, Weihong

    2013-01-01

    Background The development of molecular probes capable of recognizing virus-infected cells is essential to meet the serious clinical, therapeutic, and national-security challenges confronting virology today. We report the development of DNA aptamers as probes for the selective targeting of virus-infected living cells. Methods To create aptamer probes capable of recognizing virus-infected cells, we used cell-SELEX (systematic evolution of ligands via exponential enrichment), which uses intact infected live cells as targets for aptamer selection. In this study, vaccinia virus– infected and –uninfected lung cancer A549 cells were chosen to develop our model probes. Results A panel of aptamers has been evolved by means of the infected cell–SELEX procedure. The results demonstrate that the aptamers bind selectively to vaccinia virus–infected A549 cells with apparent equilibrium dissociation constants in the nanomolar range. In addition, these aptamers can specifically recognize a variety of target infected cell lines. The aptamers' target is most likely a viral protein located on the cell surface. Conclusions The success of developing a panel of DNA-aptamer probes capable of recognizing virus-infected cells via a whole living cell–SELEX selection strategy may increase our understanding of the molecular signatures of infected cells. Our findings suggest that aptamers can be developed as molecular probes for use as diagnostic and therapeutic reagents and for facilitating drug delivery against infected cells. PMID:19246617

  14. Mechanisms of iPS cell generation and beyond.

    PubMed

    Kaji, Keisuke

    2017-01-01

    The generation of induced pluripotent stem cells (iPSCs) achieved by overexpression of Oct4, Sox2, Klf4 and c-Myc, transformed our classical views of the cellular epigenetic landscape and delivered a new concept for cell and tissue engineering. In addition to iPSCs, several other cell types have also been generated by master transcription factor (TF)-mediated transdifferentiation. However, the critical molecular mechanisms amongst diverse cellular identity changes are not well understood. Through the investigation of reprogramming mechanisms, we recently revealed that over-expression of constitutive active Smad3 boosted not only iPSC generation, but also 3 other master TF-mediated conversions, from B cells to macrophages, myoblasts to adipocytes, and human fibroblasts to neurons. This demonstrated that there were common mechanisms underlying different master TF-mediated cell conversions. To illuminate such mechanisms further, we have recently performed CRISPR/Cas9-mediated genome-wide knockout screening during reprogramming with a lentiviral gRNA library containing 90,000 gRNAs. This screening provided us with ~15 novel reprogramming roadblock genes as well as ~20 candidate genes essential for the reprogramming process but not for ES cell self-renewal. This data set will be a valuable resource to further understand how overexpression of master TFs alters cellular identity, and to achieve more faithful, efficient cell conversions for regenerative medicine.(Presented at the 1934th Meeting, March 17, 2017).

  15. HLA type-independent generation of antigen-specific T cells for adoptive immunotherapy.

    PubMed

    Hammer, Markus H; Meyer, Sonja; Brestrich, Gordon; Moosmann, Andreas; Kern, Florian; Tesfa, Lydia; Babel, Nina; Mittenzweig, Alexa; Rooney, Cliona M; Hammerschmidt, Wolfgang; Volk, Hans-Dieter; Reinke, Petra

    2005-07-01

    Adoptive immunotherapy with antigen-specific T cells has been successfully used to treat certain infectious diseases and cancers. Although more patients may profit from T cell therapy, its more frequent use is restricted by limitations in current T cell generation strategies. The most commonly applied peptide-based approaches rely on the knowledge of relevant epitopes. Therefore, T cells cannot be generated for diseases with unknown epitopes or for patients with unfavorable HLA types. We developed a peptide-based approach for HLA type-independent generation of specific T cells against various proteins. It is based on short-time stimulation with peptide libraries that cover most CD4(+) and CD8(+) T cell epitopes of given proteins. The procedure requires no prior knowledge of epitopes because libraries are synthesized solely on the basis of the protein's amino acid sequence. Stimulation is followed by immunomagnetic selection of activated IFN-gamma-secreting cells and nonspecific expansion. To evaluate the protocol, we generated autologous T cells specific for a well-characterized antigen, the human cytomegalovirus phosphoprotein 65 (pp65). Generated T cell lines consisted of pp65-specific CD4(+) and CD8(+) lymphocytes that displayed antigen-specific killing and proliferation. The protocol combines the biosafety of peptide-based approaches with HLA type independence and may help to advance adoptive immunotherapy in the future.

  16. Riboflavin in development and cell fate.

    PubMed

    Powers, Hilary J; Corfe, B M; Nakano, E

    2012-01-01

    Riboflavin (7,8-dimethyl-10-ribitylisoalloxazine; vitamin B2) is a water-soluble vitamin, cofactor derivatives of which (FAD, FMN) act as electron acceptors in the oxidative metabolism of carbohydrate, amino acids and fatty acids and which in the reduced state can donate electrons to complex II of the electron transport chain. This means that riboflavin is essential for energy generation in the aerobic cell, through oxidative phosphorylation. The classic effects of riboflavin deficiency on growth and development have generally been explained in terms of these functions. However, research also suggests that riboflavin may have specific functions associated with cell fate determination, which would have implications for growth and development. In particular, riboflavin depletion interferes with the normal progression of the cell cycle, probably through effects on the expression of regulatory genes, exerted at both the transcriptional and proteomic level.

  17. Silicon concentrator solar cell development

    NASA Astrophysics Data System (ADS)

    Green, Martin A.; Jianhua, Zhao; Aihua, Wang; Blakers, A. W.

    1990-05-01

    This project involved the development and supply of 550 silicon concentrator solar cells for use in prototype point-focus concentrator modules. The cells were to have a designed illumination area of 12.5 by 12.5 mm and to be designed for use with prismatic covers at a geometric concentration ratio of 200X. The target efficiency of 24 percent was comfortably exceeded, with efficiencies as high as 25.2 percent reached in the designed concentration ratio range. A combined lens/cell efficiency of 24.4 percent was measured at Sandia using a cell supplied during this project and a point focus Fresnel lens. Subsequently, a peak module efficiency of 20.3 percent was achieved at Sandia using 12 cells and lenses. This is believed to be the first photovoltaic module to surpass the 20 percent efficiency milestone.

  18. Generation of folliculogenic human epithelial stem cells from induced pluripotent stem cells

    NASA Astrophysics Data System (ADS)

    Yang, Ruifeng; Zheng, Ying; Burrows, Michelle; Liu, Shujing; Wei, Zhi; Nace, Arben; Guo, Wei; Kumar, Suresh; Cotsarelis, George; Xu, Xiaowei

    2014-01-01

    Epithelial stem cells (EpSCs) in the hair follicle bulge are required for hair follicle growth and cycling. The isolation and propagation of human EpSCs for tissue engineering purposes remains a challenge. Here we develop a strategy to differentiate human iPSCs (hiPSCs) into CD200+/ITGA6+ EpSCs that can reconstitute the epithelial components of the hair follicle and interfollicular epidermis. The hiPSC-derived CD200+/ITGA6+ cells show a similar gene expression signature as EpSCs directly isolated from human hair follicles. Human iPSC-derived CD200+/ITGA6+ cells are capable of generating all hair follicle lineages including the hair shaft, and the inner and outer root sheaths in skin reconstitution assays. The regenerated hair follicles possess a KRT15+ stem cell population and produce hair shafts expressing hair-specific keratins. These results suggest an approach for generating large numbers of human EpSCs for tissue engineering and new treatments for hair loss, wound healing and other degenerative skin disorders.

  19. Progress and obstacles towards generating hematopoietic stem cells from pluripotent stem cells

    PubMed Central

    Lee, Jungmin; Dykstra, Brad; Sackstein, Robert; Rossi, Derrick J.

    2015-01-01

    Purpose of review Human pluripotent stem cells (PSCs) have the potential to provide an inexhaustible source of hematopoietic stem cells (HSCs) that could be used in disease modeling and in clinical applications such as transplantation. Although the goal of deriving definitive HSCs from PSCs has not been achieved, recent studies indicate that progress is being made. This review will provide information on the current status of deriving HSCs from PSCs, and will highlight existing challenges and obstacles. Recent findings Recent strides in HSC generation from PSCs has included derivation of developmental intermediates, identification of transcription factors and small molecules that support hematopoietic derivation, and the development of strategies to recapitulate niche-like conditions. Summary Despite considerable progress in defining the molecular events driving derivation of hematopoietic progenitor cells (HPCs) from PSCs, the generation of robust transplantable HSCs from PSCs remains elusive. We propose that this goal can be facilitated by better understanding of the regulatory pathways governing HSC identity, development of HSC supportive conditions, and examining the marrow homing properties of PSC-derived HSCs. PMID:26049752

  20. Next Generation Photovoltaics Based on Multiple Exciton Generation in Quantum Dot Solar Cells

    NASA Astrophysics Data System (ADS)

    Nozik, Arthur J.

    Next Generation solar cells based onMultiple Exciton Generation (MEG) in semiconductorquantum dots (QDs) are described. This application of QDs depends upon efficient MEG in QDs incorporated into PV cells, followed by efficient exciton splitting into free electrons and holes and their efficient separation and collection in the cell contacts to produce multiple free carriers per absorbed photon. Using time-resolved transient absorption, bleaching, photoluminescence and THz spectroscopy, MEG has been initially confirmed in several Group IV-VI, III-V, II-VI, and IV colloidal semiconductor QDs. Some controversy using these techniques have now been attributed to effects of the variable of the QD surface chemisty and under certain conditions to artifacts arising from long-lived trapping of photoinduced charge; in our opinion these controversies have been resolved and are discussed here. Furthermore, various photovoltaic cell architectures utilizing QDs have recently been constructed and the photocurrent and photovoltage characterisitics have been studied. These photocurrent measurements provide a more direct measurement of MEG since the photogenerated carriers are counted directly via the current, and they are very consistent with the QYs of MEG reported using the proper spectroscopic techniques; thus, these new photocurrent measurements confirm the existence of enhanced exciton and carrier multiplication in QDs. The past work and prognosis for QD-based Next Generation PV cells based on MEG are discussed.

  1. Converting cell fates: generating hematopoietic stem cells de novo via transcription factor reprogramming.

    PubMed

    Daniel, Michael G; Lemischka, Ihor R; Moore, Kateri

    2016-04-01

    Even though all paradigms of stem cell therapy and regenerative medicine emerged from the study of hematopoietic stem cells (HSCs), the inability to generate these cells de novo or expand them in vitro persists. Initial efforts to obtain these cells began with the use of embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) technologies, but these strategies have yet to yield fully functional cells. Subsequently, more recent approaches involve transcription factor (TF) overexpression to reprogram PSCs and various somatic cells. The induction of pluripotency with just four TFs by Yamanaka informs our ability to convert cell fates and demonstrates the feasibility of utilizing terminally differentiated cells to generate cells with multilineage potential. In this review, we discuss the recent efforts undertaken using TF-based reprogramming strategies to convert several cell types into HSCs. © 2016 New York Academy of Sciences.

  2. Bcl10 plays a divergent role in NK cell-mediated cytotoxicity and cytokine generation.

    PubMed

    Malarkannan, Subramaniam; Regunathan, Jeyarani; Chu, Haiyan; Kutlesa, Snjezana; Chen, Yuhong; Zeng, Hu; Wen, Renren; Wang, Demin

    2007-09-15

    Activating receptors such as NKG2D and Ly49D mediate a multitude of effector functions including cytotoxicity and cytokine generation in NK cells. However, specific signaling events that are responsible for the divergence of distinct effector functions have yet to be determined. In this study, we show that lack of caspase recruitment domain-containing protein Bcl10 significantly affected receptor-mediated cytokine and chemokine generation, but not cytotoxicity against tumor cells representing "missing-self" or "induced-self." Lack of Bcl10 completely abrogated the generation of GM-CSF and chemokines and it significantly reduced the generation of IFN-gamma (>75%) in NK cells. Commitment, development, and terminal maturation of NK cells were largely unaffected in the absence of Bcl10. Although IL-2-activated NK cells could mediate cytotoxicity to the full extent, the ability of the freshly isolated NK cells to mediate cytotoxicity was somewhat reduced. Therefore, we conclude that the Carma1-Bcl10-Malt1 signaling axis is critical for cytokine and chemokine generation, although it is dispensable for cytotoxic granule release depending on the activation state of NK cells. These results indicate that Bcl10 represents an exclusive "molecular switch" that links the upstream receptor-mediated signaling to cytokine and chemokine generations.

  3. CD4 T-Cell Memory Generation and Maintenance

    PubMed Central

    Gasper, David J.; Tejera, Melba Marie; Suresh, M.

    2014-01-01

    Immunologic memory is the adaptive immune system's powerful ability to remember a previous antigen encounter and react with accelerated vigor upon antigen re-exposure. It provides durable protection against reinfection with pathogens and is the foundation for vaccine-induced immunity. Unlike the relatively restricted immunologic purview of memory B cells and CD8 T cells, the field of CD4 T-cell memory must account for multiple distinct lineages with diverse effector functions, the issue of lineage commitment and plasticity, and the variable distribution of memory cells within each lineage. Here, we discuss the evidence for lineage-specific CD4 T-cell memory and summarize the known factors contributing to memory-cell generation, plasticity, and long-term maintenance. PMID:24940912

  4. Generation of functional podocytes from human induced pluripotent stem cells.

    PubMed

    Ciampi, Osele; Iacone, Roberto; Longaretti, Lorena; Benedetti, Valentina; Graf, Martin; Magnone, Maria Chiara; Patsch, Christoph; Xinaris, Christodoulos; Remuzzi, Giuseppe; Benigni, Ariela; Tomasoni, Susanna

    2016-07-01

    Generating human podocytes in vitro could offer a unique opportunity to study human diseases. Here, we describe a simple and efficient protocol for obtaining functional podocytes in vitro from human induced pluripotent stem cells. Cells were exposed to a three-step protocol, which induced their differentiation into intermediate mesoderm, then into nephron progenitors and, finally, into mature podocytes. After differentiation, cells expressed the main podocyte markers, such as synaptopodin, WT1, α-Actinin-4, P-cadherin and nephrin at the protein and mRNA level, and showed the low proliferation rate typical of mature podocytes. Exposure to Angiotensin II significantly decreased the expression of podocyte genes and cells underwent cytoskeleton rearrangement. Cells were able to internalize albumin and self-assembled into chimeric 3D structures in combination with dissociated embryonic mouse kidney cells. Overall, these findings demonstrate the establishment of a robust protocol that, mimicking developmental stages, makes it possible to derive functional podocytes in vitro.

  5. Generating pluripotent stem cells: Differential epigenetic changes during cellular reprogramming

    PubMed Central

    Tobin, Stacey C.; Kim, Kitai

    2013-01-01

    Pluripotent stem cells hold enomous potential for therapuetic applications in tissue replacement therapy. Reprogramming somatic cells from a patient donor to generate pluripotent stem cells involves both ethical concerns inherent in the use of embryonic and oocyte-derived stem cells, as well as issues of histocompatibility. Among the various pluripotent stem cells, induced pluripotent stem cells (iPSC)—derived by ectopic expression of four reprogramming factors in donor somatic cells—are superior in terms of ethical use, histocompatibility, and derivation method. However, iPSC also show genetic and epigenetic differences that limit their differentiation potential, functionality, safety, and potential clinical utility. Here, we discuss the unique characteristics of iPSC and approaches that are being taken to overcome these limitations. PMID:22819821

  6. CD4 T-cell memory generation and maintenance.

    PubMed

    Gasper, David J; Tejera, Melba Marie; Suresh, M

    2014-01-01

    Immunologic memory is the adaptive immune system's powerful ability to remember a previous antigen encounter and react with accelerated vigor upon antigen re-exposure. It provides durable protection against reinfection with pathogens and is the foundation for vaccine-induced immunity. Unlike the relatively restricted immunologic purview of memory B cells and CD8 T cells, the field of CD4 T-cell memory must account for multiple distinct lineages with diverse effector functions, the issue of lineage commitment and plasticity, and the variable distribution of memory cells within each lineage. Here, we discuss the evidence for lineage-specific CD4 T-cell memory and summarize the known factors contributing to memory-cell generation, plasticity, and long-term maintenance.

  7. Developing Assessments for the Next Generation Science Standards

    ERIC Educational Resources Information Center

    Pellegrino, James W., Ed.; Wilson, Mark R., Ed.; Koenig, Judith A., Ed.; Beatty, Alexandra S., Ed.

    2014-01-01

    Assessments, understood as tools for tracking what and how well students have learned, play a critical role in the classroom. "Developing Assessments for the Next Generation Science Standards" develops an approach to science assessment to meet the vision of science education for the future as it has been elaborated in "A Framework…

  8. Developing Assessments for the Next Generation Science Standards

    ERIC Educational Resources Information Center

    Pellegrino, James W., Ed.; Wilson, Mark R., Ed.; Koenig, Judith A., Ed.; Beatty, Alexandra S., Ed.

    2014-01-01

    Assessments, understood as tools for tracking what and how well students have learned, play a critical role in the classroom. "Developing Assessments for the Next Generation Science Standards" develops an approach to science assessment to meet the vision of science education for the future as it has been elaborated in "A Framework…

  9. Generation of transgenic rats through induced pluripotent stem cells.

    PubMed

    Jiang, Ming-Gui; Li, Tianda; Feng, Chunjing; Fu, Rui; Yuan, Yan; Zhou, Quan; Li, Xin; Wan, Haifeng; Wang, Liu; Li, Wei; Xiao, Yamei; Zhao, Xiao-Yang; Zhou, Qi

    2013-09-20

    The rat is an important animal model for human disease research. Using inhibitors of glycogen synthase kinase 3 and MAPK signaling pathways, rat embryonic stem cells and rat induced pluripotent stem cells (riPSCs) have been derived. However, unlike rat embryonic stem cells, germ line competent riPSCs have only been derived from Wistar rats at low efficiency. Here, we found that an optimized induction medium containing knock-out serum replacement and vitamin C improved the rate and efficiency of riPSCs generation from Dark Agouti rat fibroblasts and Sertoli cells. riPSCs maintained an undifferentiated status for >30 passages and could differentiate into various cells types including germ cells when injected into rat blastocysts. Moreover, transgenic riPSCs could be generated through the PiggyBac transposon, which could be used to generate transgenic rats through germ line transmission. riPSCs can be used as a novel tool in genetic and genomic studies of the rat.

  10. Generation of male differentiated germ cells from various types of stem cells.

    PubMed

    Hou, Jingmei; Yang, Shi; Yang, Hao; Liu, Yang; Liu, Yun; Hai, Yanan; Chen, Zheng; Guo, Ying; Gong, Yuehua; Gao, Wei-Qiang; Li, Zheng; He, Zuping

    2014-06-01

    Infertility is a major and largely incurable disease caused by disruption and loss of germ cells. It affects 10-15% of couples, and male factor accounts for half of the cases. To obtain human male germ cells 'especially functional spermatids' is essential for treating male infertility. Currently, much progress has been made on generating male germ cells, including spermatogonia, spermatocytes, and spermatids, from various types of stem cells. These germ cells can also be used in investigation of the pathology of male infertility. In this review, we focused on advances on obtaining male differentiated germ cells from different kinds of stem cells, with an emphasis on the embryonic stem (ES) cells, the induced pluripotent stem (iPS) cells, and spermatogonial stem cells (SSCs). We illustrated the generation of male differentiated germ cells from ES cells, iPS cells and SSCs, and we summarized the phenotype for these stem cells, spermatocytes and spermatids. Moreover, we address the differentiation potentials of ES cells, iPS cells and SSCs. We also highlight the advantages, disadvantages and concerns on derivation of the differentiated male germ cells from several types of stem cells. The ability of generating mature and functional male gametes from stem cells could enable us to understand the precise etiology of male infertility and offer an invaluable source of autologous male gametes for treating male infertility of azoospermia patients. © 2014 Society for Reproduction and Fertility.

  11. 2nd Generation Reusable Launch Vehicle Potential Commercial Development Scenarios

    NASA Technical Reports Server (NTRS)

    Creech, Stephen D.; Rogacki, John R. (Technical Monitor)

    2001-01-01

    The presentation will discuss potential commercial development scenarios for a Second Generation Reusable Launch Vehicle. The analysis of potential scenarios will include commercial rates of return, government return on investment, and market considerations. The presentation will include policy considerations in addition to analysis of Second Generation Reusable Launch Vehicle economics. The data discussed is being developed as a part of NASA's Second Generation Reusable Launch Vehicle Program, for consideration as potential scenarios for enabling a next generation system. Material will include potential scenarios not previously considered by NASA or presented at other conferences. Candidate paper has not been presented at a previous meeting, and conference attendance of the author has been approved by NASA.

  12. 2nd Generation Reusable Launch Vehicle Potential Commercial Development Scenarios

    NASA Technical Reports Server (NTRS)

    Creech, Stephen D.; Rogacki, John R. (Technical Monitor)

    2001-01-01

    The presentation will discuss potential commercial development scenarios for a Second Generation Reusable Launch Vehicle. The analysis of potential scenarios will include commercial rates of return, government return on investment, and market considerations. The presentation will include policy considerations in addition to analysis of Second Generation Reusable Launch Vehicle economics. The data discussed is being developed as a part of NASA's Second Generation Reusable Launch Vehicle Program, for consideration as potential scenarios for enabling a next generation system. Material will include potential scenarios not previously considered by NASA or presented at other conferences. Candidate paper has not been presented at a previous meeting, and conference attendance of the author has been approved by NASA.

  13. Expedient generation of patterned surface aldehydes by microfluidic oxidation for chemoselective immobilization of ligands and cells.

    PubMed

    Westcott, Nathan P; Pulsipher, Abigail; Lamb, Brian M; Yousaf, Muhammad N

    2008-09-02

    An expedient and inexpensive method to generate patterned aldehydes on self-assembled monolayers (SAMs) of alkanethiolates on gold with control of density for subsequent chemoselective immobilization from commercially available starting materials has been developed. Utilizing microfluidic cassettes, primary alcohol oxidation of tetra(ethylene glycol) undecane thiol and 11-mercapto-1-undecanol SAMs was performed directly on the surface generating patterned aldehyde groups with pyridinium chlorochromate. The precise density of surface aldehydes generated can be controlled and characterized by electrochemistry. For biological applications, fibroblast cells were seeded on patterned surfaces presenting biospecifc cell adhesive (Arg-Glyc-Asp) RGD peptides.

  14. Prospective Identification of Glioblastoma Cells Generating Dormant Tumors

    PubMed Central

    Segal, Ehud; Ma, Lili; Dixit, Niharika; Ijaz, Ambreen; Hlatky, Lynn; Abdollahi, Amir; Almog, Nava

    2012-01-01

    Although dormant tumors are highly prevalent within the human population, the underlying mechanisms are still mostly unknown. We have previously identified the consensus gene expression pattern of dormant tumors. Here, we show that this gene expression signature could be used for the isolation and identification of clones which generate dormant tumors. We established single cell-derived clones from the aggressive tumor-generating U-87 MG human glioblastoma cell line. Based only on the expression pattern of genes which were previously shown to be associated with tumor dormancy, we identified clones which generate dormant tumors. We show that very high expression levels of thrombospondin and high expression levels of angiomotin and insulin-like growth factor binding protein 5 (IGFBP5), together with low levels of endothelial specific marker (ESM) 1 and epithelial growth factor receptor (EGFR) characterize the clone which generates dormant U-87 MG derived glioblastomas. These tumors remained indolent both in subcutaneous and orthotopic intracranial sites, in spite of a high prevalence of proliferating cells. We further show that tumor cells which form U-87 MG derived dormant tumors have an impaired angiogenesis potential both in vitro and in vivo and have a slower invasion capacity. This work demonstrates that fast-growing tumors contain tumor cells that when isolated will form dormant tumors and serves as a proof-of-concept for the use of transcriptome profiles in the identification of such cells. Isolating the tumor cells that form dormant tumors will facilitate understanding of the underlying mechanisms of dormant micro-metastases, late recurrence, and changes in rate of tumor progression. PMID:22970208

  15. Aire and T cell Development

    PubMed Central

    Anderson, Mark S.; Su, Maureen A.

    2011-01-01

    In the thymus, developing T cells that react against self-antigens with high affinity are deleted in the process of negative selection. An essential component of this process is the display of self-antigens, including those whose expression are usually restricted to specific tissues, to developing T cells within the thymus. The Autoimmune Regulator (Aire) gene plays a critical role in the expression of tissue specific self-antigens within the thymus, and disruption of Aire function results in spontaneous autoimmunity in both humans and mice. Recent advances have been made in our understanding of how Aire influences the expression of thousands of tissue-specific antigens in the thymus. Additional roles of Aire, including roles in chemokine and cytokine expression, have also been revealed. Factors important in the differentiation of Aire-expressing medullary thymic epithelial cells have been defined. Finally, the identity of antigen presenting cells in negative selection, including the role of medullary thymic epithelial cells in displaying tissue specific antigens to T cells, has also been clarified. PMID:21163636

  16. Generation of bovine transgenics using somatic cell nuclear transfer

    PubMed Central

    Hodges, Craig A; Stice, Steven L

    2003-01-01

    The ability to produce transgenic animals through the introduction of exogenous DNA has existed for many years. However, past methods available to generate transgenic animals, such as pronuclear microinjection or the use of embryonic stem cells, have either been inefficient or not available in all animals, bovine included. More recently somatic cell nuclear transfer has provided a method to create transgenic animals that overcomes many deficiencies present in other methods. This review summarizes the benefits of using somatic cell nuclear transfer to create bovine transgenics as well as the possible opportunities this method creates for the future. PMID:14613543

  17. Generation of bovine transgenics using somatic cell nuclear transfer.

    PubMed

    Hodges, Craig A; Stice, Steven L

    2003-11-07

    The ability to produce transgenic animals through the introduction of exogenous DNA has existed for many years. However, past methods available to generate transgenic animals, such as pronuclear microinjection or the use of embryonic stem cells, have either been inefficient or not available in all animals, bovine included. More recently somatic cell nuclear transfer has provided a method to create transgenic animals that overcomes many deficiencies present in other methods. This review summarizes the benefits of using somatic cell nuclear transfer to create bovine transgenics as well as the possible opportunities this method creates for the future.

  18. CIF2Cell: Generating geometries for electronic structure programs

    NASA Astrophysics Data System (ADS)

    Björkman, Torbjörn

    2011-05-01

    The CIF2Cell program generates the geometrical setup for a number of electronic structure programs based on the crystallographic information in a Crystallographic Information Framework (CIF) file. The program will retrieve the space group number, Wyckoff positions and crystallographic parameters, make a sensible choice for Bravais lattice vectors (primitive or principal cell) and generate all atomic positions. Supercells can be generated and alloys are handled gracefully. The code currently has output interfaces to the electronic structure programs ABINIT, CASTEP, CPMD, Crystal, Elk, Exciting, EMTO, Fleur, RSPt, Siesta and VASP. Program summaryProgram title: CIF2Cell Catalogue identifier: AEIM_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIM_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPL version 3 No. of lines in distributed program, including test data, etc.: 12 691 No. of bytes in distributed program, including test data, etc.: 74 933 Distribution format: tar.gz Programming language: Python (versions 2.4-2.7) Computer: Any computer that can run Python (versions 2.4-2.7) Operating system: Any operating system that can run Python (versions 2.4-2.7) Classification: 7.3, 7.8, 8 External routines: PyCIFRW [1] Nature of problem: Generate the geometrical setup of a crystallographic cell for a variety of electronic structure programs from data contained in a CIF file. Solution method: The CIF file is parsed using routines contained in the library PyCIFRW [1], and crystallographic as well as bibliographic information is extracted. The program then generates the principal cell from symmetry information, crystal parameters, space group number and Wyckoff sites. Reduction to a primitive cell is then performed, and the resulting cell is output to suitably named files along with documentation of the information source generated from any bibliographic information contained in the CIF

  19. Generation of oxygen gradients in microfluidic devices for cell culture using spatially confined chemical reactions.

    PubMed

    Chen, Yung-Ann; King, Andrew D; Shih, Hsiu-Chen; Peng, Chien-Chung; Wu, Chueh-Yu; Liao, Wei-Hao; Tung, Yi-Chung

    2011-11-07

    This paper reports a microfluidic device capable of generating oxygen gradients for cell culture using spatially confined chemical reactions with minimal chemical consumption. The microfluidic cell culture device is constructed by single-layer polydimethylsiloxane (PDMS) microfluidic channels, in which the cells can be easily observed by microscopes. The device can control the oxygen gradients without the utilization of bulky pressurized gas cylinders, direct addition of oxygen scavenging agents, or tedious gas interconnections and sophisticated flow control. In addition, due to the efficient transportation of oxygen within the device using the spatially confined chemical reactions, the microfluidic cell culture device can be directly used in conventional cell incubators without altering their gaseous compositions. The oxygen gradients generated in the device are numerically simulated and experimentally characterized using an oxygen-sensitive fluorescence dye. In this paper, carcinomic human alveolar basal epithelial (A549) cells have been cultured in the microfluidic device with a growth medium and an anti-cancer drug (Tirapazamine, TPZ) under various oxygen gradients. The cell experiment results successfully demonstrate the hyperoxia-induced cell death and hypoxia-induced cytotoxicity of TPZ. In addition, the results confirm the great cell compatibility and stable oxygen gradient generation of the developed device. Consequently, the microfluidic cell culture device developed in this paper is promising to be exploited in biological labs with minimal instrumentation to study cellular responses under various oxygen gradients. This journal is © The Royal Society of Chemistry 2011

  20. Inactivation of Geminin in neural crest cells affects the generation and maintenance of enteric progenitor cells, leading to enteric aganglionosis.

    PubMed

    Stathopoulou, Athanasia; Natarajan, Dipa; Nikolopoulou, Pinelopi; Patmanidi, Alexandra L; Lygerou, Zoi; Pachnis, Vassilis; Taraviras, Stavros

    2016-01-15

    Neural crest cells comprise a multipotent, migratory cell population that generates a diverse array of cell and tissue types, during vertebrate development. Enteric Nervous System controls the function of the gastrointestinal tract and is mainly derived from the vagal and sacral neural crest cells. Deregulation on self-renewal and differentiation of the enteric neural crest cells is evident in enteric nervous system disorders, such as Hirschsprung disease, characterized by the absence of ganglia in a variable length of the distal bowel. Here we show that Geminin is essential for Enteric Nervous System generation as mice that lacked Geminin expression specifically in neural crest cells revealed decreased generation of vagal neural crest cells, and enteric neural crest cells (ENCCs). Geminin-deficient ENCCs showed increased apoptosis and decreased cell proliferation during the early stages of gut colonization. Furthermore, decreased number of committed ENCCs in vivo and the decreased self-renewal capacity of enteric progenitor cells in vitro, resulted in almost total aganglionosis resembling a severe case of Hirschsprung disease. Our results suggest that Geminin is an important regulator of self-renewal and survival of enteric nervous system progenitor cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Development of large wind energy power generation system

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The background and development of an experimental 100 kW wind-energy generation system are described, and the results of current field tests are presented. The experimental wind turbine is a two-bladed down-wind horizontal axis propeller type with a 29.4 m diameter rotor and a tower 28 m in height. The plant was completed in March, 1983, and has been undergoing trouble-free tests since then. The present program calls for field tests during two years from fiscal 1983 to 1984. The development of technologies relating to the linkage and operation of wind-energy power generation system networks is planned along with the acquisition of basic data for the development of a large-scale wind energy power generation system.

  2. Generation and sequencing of pulmonary carcinoid tumor cell lines.

    PubMed

    Asiedu, Michael K; Thomas, Charles F; Tomaszek, Sandra C; Peikert, Tobias; Sanyal, Bharati; Sutor, Shari L; Aubry, Marie-Christine; Li, Peter; Wigle, Dennis A

    2014-12-01

    Pulmonary carcinoid tumors account for approximately 5% of all lung malignancies in adults, and comprise 30% of all carcinoid tumors. There are limited reagents available to study these rare tumors, and consequently no major advances have been made for patient treatment. We report the generation and characterization of human pulmonary carcinoid tumor cell lines to study underlying biology, and to provide models for testing novel chemotherapeutic agents. Tissue was harvested from three patients with primary pulmonary typical carcinoid tumors undergoing surgical resection. The tumor was dissociated and plated onto dishes in culture media. The established cell lines were characterized by immunohistochemistry, Western blotting, and cell proliferation assays. Tumorigenicity was confirmed by soft agar growth and the ability to form tumors in a mouse xenograft model. Exome and RNA sequencing of patient tumor samples and cell lines was performed using standard protocols. Three typical carcinoid tumor lines grew as adherent monolayers in vitro, expressed neuroendocrine markers consistent with the primary tumor, and formed colonies in soft agar. A single cell line produced lung tumors in nude mice after intravenous injection. Exome and RNA sequencing of this cell line showed lineage relationship with the primary tumor, and demonstrated mutations in a number of genes related to neuronal differentiation. Three human pulmonary typical carcinoid tumor cell lines have been generated and characterized as a tool for studying the biology and novel treatment approaches for these rare tumors.

  3. Large-scale generation of cell-derived nanovesicles

    NASA Astrophysics Data System (ADS)

    Jo, W.; Kim, J.; Yoon, J.; Jeong, D.; Cho, S.; Jeong, H.; Yoon, Y. J.; Kim, S. C.; Gho, Y. S.; Park, J.

    2014-09-01

    Exosomes are enclosed compartments that are released from cells and that can transport biological contents for the purpose of intercellular communications. Research into exosomes is hindered by their rarity. In this article, we introduce a device that uses centrifugal force and a filter with micro-sized pores to generate a large quantity of cell-derived nanovesicles. The device has a simple polycarbonate structure to hold the filter, and operates in a common centrifuge. Nanovesicles are similar in size and membrane structure to exosomes. Nanovesicles contain intracellular RNAs ranging from microRNA to mRNA, intracellular proteins, and plasma membrane proteins. The quantity of nanovesicles produced using the device is 250 times the quantity of naturally secreted exosomes. Also, the quantity of intracellular contents in nanovesicles is twice that in exosomes. Nanovesicles generated from murine embryonic stem cells can transfer RNAs to target cells. Therefore, this novel device and the nanovesicles that it generates are expected to be used in exosome-related research, and can be applied in various applications such as drug delivery and cell-based therapy.

  4. Large-scale generation of cell-derived nanovesicles.

    PubMed

    Jo, W; Kim, J; Yoon, J; Jeong, D; Cho, S; Jeong, H; Yoon, Y J; Kim, S C; Gho, Y S; Park, J

    2014-10-21

    Exosomes are enclosed compartments that are released from cells and that can transport biological contents for the purpose of intercellular communications. Research into exosomes is hindered by their rarity. In this article, we introduce a device that uses centrifugal force and a filter with micro-sized pores to generate a large quantity of cell-derived nanovesicles. The device has a simple polycarbonate structure to hold the filter, and operates in a common centrifuge. Nanovesicles are similar in size and membrane structure to exosomes. Nanovesicles contain intracellular RNAs ranging from microRNA to mRNA, intracellular proteins, and plasma membrane proteins. The quantity of nanovesicles produced using the device is 250 times the quantity of naturally secreted exosomes. Also, the quantity of intracellular contents in nanovesicles is twice that in exosomes. Nanovesicles generated from murine embryonic stem cells can transfer RNAs to target cells. Therefore, this novel device and the nanovesicles that it generates are expected to be used in exosome-related research, and can be applied in various applications such as drug delivery and cell-based therapy.

  5. Optimized Sleeping Beauty transposons rapidly generate stable transgenic cell lines.

    PubMed

    Kowarz, Eric; Löscher, Denise; Marschalek, Rolf

    2015-04-01

    Stable gene expression in mammalian cells is a prerequisite for many in vitro and in vivo experiments. However, either the integration of plasmids into mammalian genomes or the use of retro-/lentiviral systems have intrinsic limitations. The use of transposable elements, e.g. the Sleeping Beauty system (SB), circumvents most of these drawbacks (integration sites, size limitations) and allows the quick generation of stable cell lines. The integration process of SB is catalyzed by a transposase and the handling of this gene transfer system is easy, fast and safe. Here, we report our improvements made to the existing SB vector system and present two new vector types for robust constitutive or inducible expression of any gene of interest. Both types are available in 16 variants with different selection marker (puromycin, hygromycin, blasticidin, neomycin) and fluorescent protein expression (GFP, RFP, BFP) to fit most experimental requirements. With this system it is possible to generate cell lines from stable transfected cells quickly and reliably in a medium-throughput setting (three to five days). Cell lines robustly express any gene-of-interest, either constitutively or tightly regulated by doxycycline. This allows many laboratory experiments to speed up generation of data in a rapid and robust manner. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Pluripotent stem cell-derived radial glia-like cells as stable intermediate for efficient generation of human oligodendrocytes.

    PubMed

    Gorris, Raphaela; Fischer, Julia; Erwes, Kim Lina; Kesavan, Jaideep; Peterson, Daniel A; Alexander, Michael; Nöthen, Markus M; Peitz, Michael; Quandel, Tamara; Karus, Michael; Brüstle, Oliver

    2015-12-01

    Neural precursor cells (NPCs) derived from human pluripotent stem cells (hPSCs) represent an attractive tool for the in vitro generation of various neural cell types. However, the developmentally early NPCs emerging during hPSC differentiation typically show a strong propensity for neuronal differentiation, with more limited potential for generating astrocytes and, in particular, for generating oligodendrocytes. This phenomenon corresponds well to the consecutive and protracted generation of neurons and GLIA during normal human development. To obtain a more gliogenic NPC type, we combined growth factor-mediated expansion with pre-exposure to the differentiation-inducing agent retinoic acid and subsequent immunoisolation of CD133-positive cells. This protocol yields an adherent and self-renewing population of hindbrain/spinal cord radial glia (RG)-like neural precursor cells (RGL-NPCs) expressing typical neural stem cell markers such as nestin, ASCL1, SOX2, and PAX6 as well as RG markers BLBP, GLAST, vimentin, and GFAP. While RGL-NPCs maintain the ability for tripotential differentiation into neurons, astrocytes, and oligodendrocytes, they exhibit greatly enhanced propensity for oligodendrocyte generation. Under defined differentiation conditions promoting the expression of the major oligodendrocyte fate-determinants OLIG1/2, NKX6.2, NKX2.2, and SOX10, RGL-NPCs efficiently convert into NG2-positive oligodendroglial progenitor cells (OPCs) and are subsequently capable of in vivo myelination. Representing a stable intermediate between PSCs and OPCs, RGL-NPCs expedite the generation of PSC-derived oligodendrocytes with O4-, 4860-, and myelin basic protein (MBP)-positive cells that already appear within 7 weeks following growth factor withdrawal-induced differentiation. Thus, RGL-NPCs may serve as robust tool for time-efficient generation of human oligodendrocytes from embryonic and induced pluripotent stem cells.

  7. Hydrogen generation at ambient conditions: application in fuel cells.

    PubMed

    Boddien, Albert; Loges, Björn; Junge, Henrik; Beller, Matthias

    2008-01-01

    The efficient generation of hydrogen from formic acid/amine adducts at ambient temperature is demonstrated. The highest catalytic activity (TOF up to 3630 h(-1) after 20 min) was observed in the presence of in situ generated ruthenium phosphine catalysts. Compared to the previously known methods to generate hydrogen from liquid feedstocks, the systems presented here can be operated at room temperature without the need for any high-temperature reforming processes, and the hydrogen produced can then be directly used in fuel cells. A variety of Ru precursors and phosphine ligands were investigated for the decomposition of formic acid/amine adducts. These catalytic systems are particularly interesting for the generation of H2 for new applications in portable electric devices.

  8. Advanced Cell Development and Degradation Studies

    SciTech Connect

    J. E. O'Brien; C. M. Stoots; J. S. Herring; R. C. O'Brien; K. G. Condie; M. Sohal; G. K. Housley; J. J. Hartvigsen; D. Larsen; G. Tao; B. Yildiz; V. Sharma; P. Singh; N. Petigny; T. L. Cable

    2010-09-01

    The Idaho National Laboratory (INL) has been researching the application of solid-oxide electrolysis cells for large-scale hydrogen production from steam over a temperature range of 800 to 900ºC. From 2003 – 2009, this work was sponsored by the DOE Nuclear Hydrogen Initiative (NHI). Starting in 2010, the HTE research program has been sponsored by the Next Generation Nuclear Plant (NGNP) program. HTSE research priorities in FY10 are centered on understanding and reducing cell and stack performance degradation to an acceptable level to advance the technology readiness level of HTSE and to justify further large-scale demonstration activities. This report provides a summary of our FY10 experimental program, which has been focused on advanced cell and stack development and degradation studies. Advanced cell and stack development activities are under way at five technology partners: MSRI, Versa Power, Ceramatec, NASA Glenn, and St. Gobain. Performance evaluation of the advanced technology cells and stacks has been performed by the technology partners, by MIT and the University of Connecticut and at the INL HTE Laboratory. Summaries of these development activities and test results are presented.

  9. Generation of mesenchymal stem cell lines from murine bone marrow.

    PubMed

    Sreejit, P; Dilip, K B; Verma, R S

    2012-10-01

    Mesenchymal stem cells (MSC), because of their multipotency and ease of purification and amplification, are an ideal stem cell source for cell therapies. Bone-marrow-derived stem cells (BMSC) can be used to develop MSC-like immortalized cell lines with large proliferation and differentiation potentialities. Their immortalized status prevents the maintenance of MSC function and characters; this can be negated by modifying the isolation and maintenance protocol. Adult murine BMSC were isolated and maintained in media without additional growth factors together with passage-dependent reseeding following trypsinization. Cells maintained over 25 passages were considered as putative cell lines and characterized. The phenotypic and genotypic characteristics and multilineage differentiation potential of the cells were assessed by morphological, phenotypic, and molecular assays at various passages. The putative BMSC cell lines showed the characteristics of MSC and were able to maintain these characteristics, even after immortalization. The phenotypic data demonstrated difference among two cell lines; this was further validated by the difference in their multilineage differentiation potential following specific induction. More importantly, no changes were observed in the genotypic level in comparison with control cells, even after more than 50 passages. Our protocol thus advances the isolation and maintenance of BMSC and the development of putative BMSC cell lines that maintain characteristics of MSC, including multilineage differentiation potential, after more than 40 passages.

  10. IVHM for the 3rd Generation RLV Program: Technology Development

    NASA Technical Reports Server (NTRS)

    Kahle, Bill

    2000-01-01

    The objective behind the Integrated Vehicle Health Management (IVHM) project is to develop and integrate the technologies which can provide a continuous, intelligent, and adaptive health state of a vehicle and use this information to improve safety and reduce costs of operations. Technological areas discussed include: developing, validating, and transfering next generation IVHM technologies to near term industry and government reusable launch systems; focus NASA on the next generation and highly advanced sensor and software technologies; and validating IVHM systems engineering design process for future programs.

  11. The Peptide Specificity of the Endogenous T Follicular Helper Cell Repertoire Generated after Protein Immunization

    PubMed Central

    Leddon, Scott A.; Sant, Andrea J.

    2012-01-01

    T follicular helper (Tfh) cells potentiate high-affinity, class-switched antibody responses, the predominant correlate of protection from vaccines. Despite intense interest in understanding both the generation and effector functions of this lineage, little is known about the epitope specificity of Tfh cells generated during polyclonal responses. To date, studies of peptide-specific Tfh cells have relied on either the transfer of TcR transgenic cells or use of peptide∶MHC class II tetramers and antibodies to stain TcR and follow limited peptide specificities. In order to comprehensively evaluate polyclonal responses generated from the natural endogenous TcR repertoire, we developed a sorting strategy to separate Tfh cells from non-Tfh cells and found that their epitope-specific responses could be tracked with cytokine-specific ELISPOT assays. The immunodominance hierarchies of Tfh and non-Tfh cells generated in response to immunization with several unrelated protein antigens were remarkably similar. Additionally, increasing the kinetic stability of peptide-MHC class II complexes enhanced the priming of both Tfh and conventional CD4 T cells. These findings may provide us with a strategy to rationally and selectively modulate epitope-specific Tfh responses. By understanding the parameters that control epitope-specific priming, vaccines may be tailored to enhance or focus Tfh responses to facilitate optimal B cell responses. PMID:23077537

  12. Proinflammatory cytokine signaling required for the generation of natural killer cell memory

    PubMed Central

    Sun, Joseph C.; Madera, Sharline; Bezman, Natalie A.; Beilke, Joshua N.; Kaplan, Mark H.

    2012-01-01

    Although natural killer (NK) cells are classified as innate immune cells, recent studies demonstrate that NK cells can become long-lived memory cells and contribute to secondary immune responses. The precise signals that promote generation of long-lived memory NK cells are unknown. Using cytokine receptor-deficient mice, we show that interleukin-12 (IL-12) is indispensible for mouse cytomegalovirus (MCMV)-specific NK cell expansion and generation of memory NK cells. In contrast to wild-type NK cells that proliferated robustly and resided in lymphoid and nonlymphoid tissues for months after MCMV infection, IL-12 receptor–deficient NK cells failed to expand and were unable to mediate protection after MCMV challenge. We further demonstrate that a STAT4-dependent IFN-γ–independent mechanism contributes toward the generation of memory NK cells during MCMV infection. Understanding the full contribution of inflammatory cytokine signaling to the NK cell response against viral infection will be of interest for the development of vaccines and therapeutics. PMID:22493516

  13. Proinflammatory cytokine signaling required for the generation of natural killer cell memory.

    PubMed

    Sun, Joseph C; Madera, Sharline; Bezman, Natalie A; Beilke, Joshua N; Kaplan, Mark H; Lanier, Lewis L

    2012-05-07

    Although natural killer (NK) cells are classified as innate immune cells, recent studies demonstrate that NK cells can become long-lived memory cells and contribute to secondary immune responses. The precise signals that promote generation of long-lived memory NK cells are unknown. Using cytokine receptor-deficient mice, we show that interleukin-12 (IL-12) is indispensible for mouse cytomegalovirus (MCMV)-specific NK cell expansion and generation of memory NK cells. In contrast to wild-type NK cells that proliferated robustly and resided in lymphoid and nonlymphoid tissues for months after MCMV infection, IL-12 receptor-deficient NK cells failed to expand and were unable to mediate protection after MCMV challenge. We further demonstrate that a STAT4-dependent IFN-γ-independent mechanism contributes toward the generation of memory NK cells during MCMV infection. Understanding the full contribution of inflammatory cytokine signaling to the NK cell response against viral infection will be of interest for the development of vaccines and therapeutics.

  14. Polymer electrolyte fuel cells: a review of recent developments

    NASA Astrophysics Data System (ADS)

    Prater, Keith B.

    The very high power density available from proton-exchange membrane (PEM) fuel cells combined with the potential for very low cost suggests the PEM fuel cell as the most probable power plant for the next generation, non-polluting automobile engine. The demonstrated capability of the PEM fuel cell to produce power from avilable hydrocarbon fuels opens the possibility of reliable, efficient, power generation located near the user. This review summarizes the operating principles of the fuel cell stack and power systems, describes the current status of the technology, focusing on recent developments, and discusses the technical challenges and commercial prospectis for this fuel cell technology.

  15. Lentiviral transduction of primary myeloma cells with CD80 and CD154 generates antimyeloma effector T cells.

    PubMed

    Cignetti, Alessandro; Vallario, Antonella; Follenzi, Antonia; Circosta, Paola; Capaldi, Antonio; Gottardi, Daniela; Naldini, Luigi; Caligaris-Cappio, Federico

    2005-04-01

    The development of immunotherapy approaches designed to obtain tumor-specific T cells might help eradicate residual malignant cells in multiple myeloma (MM) patients. To this end, we used autologous primary MM cells as antigen-presenting cells (APC). Gene transfer of both CD80 and CD154 by lentiviral vectors was necessary to significantly improve the APC function of human MM cells. Simultaneous CD80/CD154 expression on MM cells allowed the generation of CD8+ T cells that recognized unmodified MM cells in 11 of 16 cases, specifically in six of six patients with low-stage disease, but only in five of ten patients with advanced disease. The activity of CD8+ T cells was MHC restricted and MM specific. In seven of seven cases, CD8+ T cell activity was inhibited by monoclonal antibodies against HLA class I, and in four of four cases, CD8+ T cells recognized autologous MM cells but not autologous normal B and T lymphocytes nor bone marrow stromal cells. In addition, the activity of CD8+ T cells was directed against allogeneic MM cells that shared at least one MHC allele with the autologous counterpart, but not against MHC mismatched MM cells. These data lay the ground for the isolation of new MM antigens and for the design of vaccination protocols with primary MM cells genetically engineered to express immunostimulatory molecules.

  16. Generation of parthenogenetic induced pluripotent stem cells from parthenogenetic neural stem cells.

    PubMed

    Do, Jeong Tae; Joo, Jin Young; Han, Dong Wook; Araúzo-Bravo, Marcos J; Kim, Min Jung; Greber, Boris; Zaehres, Holm; Sobek-Klocke, Ingeborg; Chung, Hyung Min; Schöler, Hans R

    2009-12-01

    Somatic cells can achieve a pluripotent cell state in a process called pluripotential reprogramming. Multipotent stem cells can differentiate into cells of only one lineage, but pluripotent stem cells can give rise to cells of all three germ layers of an organism. In this study, we generated induced pluripotent stem (iPS) cells from bimaternal (uniparental) parthenogenetic neural stem cells (pNSCs) by transduction with either four (4F: Oct4, Klf4, Sox2, and c-Myc) or two (2F: Oct4 and Klf4) transcription factors. The resultant maternal iPS cells, which were reprogrammed directly from pNSCs, were capable of generating germ line-competent chimeras. Interestingly, analysis of global gene expression and imprinting status revealed that parthenogenetic iPS cells clustered closer to parthenogenetic ESCs than to female ESCs, with patterns that were clearly distinct from those of pNSCs.

  17. Functional Neurons Generated from T Cell-Derived Induced Pluripotent Stem Cells for Neurological Disease Modeling

    PubMed Central

    Matsumoto, Takuya; Fujimori, Koki; Andoh-Noda, Tomoko; Ando, Takayuki; Kuzumaki, Naoko; Toyoshima, Manabu; Tada, Hirobumi; Imaizumi, Kent; Ishikawa, Mitsuru; Yamaguchi, Ryo; Isoda, Miho; Zhou, Zhi; Sato, Shigeto; Kobayashi, Tetsuro; Ohtaka, Manami; Nishimura, Ken; Kurosawa, Hiroshi; Yoshikawa, Takeo; Takahashi, Takuya; Nakanishi, Mahito; Ohyama, Manabu; Hattori, Nobutaka; Akamatsu, Wado; Okano, Hideyuki

    2016-01-01

    Summary Modeling of neurological diseases using induced pluripotent stem cells (iPSCs) derived from the somatic cells of patients has provided a means of elucidating pathogenic mechanisms and performing drug screening. T cells are an ideal source of patient-specific iPSCs because they can be easily obtained from samples. Recent studies indicated that iPSCs retain an epigenetic memory relating to their cell of origin that restricts their differentiation potential. The classical method of differentiation via embryoid body formation was not suitable for T cell-derived iPSCs (TiPSCs). We developed a neurosphere-based robust differentiation protocol, which enabled TiPSCs to differentiate into functional neurons, despite differences in global gene expression between TiPSCs and adult human dermal fibroblast-derived iPSCs. Furthermore, neurons derived from TiPSCs generated from a juvenile patient with Parkinson's disease exhibited several Parkinson's disease phenotypes. Therefore, we conclude that TiPSCs are a useful tool for modeling neurological diseases. PMID:26905201

  18. Developing models in virtual cell.

    PubMed

    Neves, Susana R

    2011-09-20

    This Teaching Resource provides lecture notes, slides, and a student assignment for a two-part lecture on mathematical modeling using the Virtual Cell environment. The lectures discuss the steps involved in developing and running simulations using Virtual Cell, with particular focus on spatial partial differential equation models. We discuss how to construct both ordinary differential equation models, in which the cytoplasm is considered a well-mixed cellular compartment, and partial differential equation models, which calculate how chemical species change as a function of both time and location. The Virtual Cell environment is especially well suited for models that explore spatial specificity of cellular reactions. Partial differential equation models in Virtual Cell can give rise to simulations using predefined cellular geometries, which enable direct comparison with imaging data. These models address questions regarding the regulatory capability arising from spatial organization of the cell. Examples are provided of studies that have successfully exploited the Virtual Cell software to address the spatial contribution to signaling.

  19. Minocycline promotes the generation of dendritic cells with regulatory properties

    PubMed Central

    Im, Sun-A; Kim, Ji-Wan; Lee, Jae-Hee; Park, Young-Jun; Song, Sukgil; Lee, Chong-Kil

    2016-01-01

    Minocycline, which has long been used as a broad-spectrum antibiotic, also exhibits non-antibiotic properties such as inhibition of inflammation and angiogenesis. In this study, we show that minocycline significantly enhances the generation of dendritic cells (DCs) from mouse bone marrow (BM) cells when used together with GM-CSF and IL-4. DCs generated from BM cells in the presence of minocycline (Mino-DCs) demonstrate the characteristics of regulatory DCs. Compared with control DCs, Mino-DCs are resistant to subsequent maturation stimuli, impaired in MHC class II-restricted exogenous Ag presentation, and show decreased cytokine secretion. Mino-DCs also show decreased ability to prime allogeneic-specific T cells, while increasing the expansion of CD4+CD25+Foxp3+ T regulatory cells both in vitro and in vivo. In addition, pretreatment with MOG35-55 peptide-pulsed Mino-DCs ameliorates clinical signs of experimental autoimmune encephalitis induced by MOG peptide injection. Our study identifies minocycline as a new pharmacological agent that could be potentially used to increase the production of regulatory DCs for cell therapy to treat autoimmune disorders, allergy, and transplant rejection. PMID:27463004

  20. Development and Interaction of Artificially Generated Hairpin Vortices

    NASA Astrophysics Data System (ADS)

    Sabatino, Daniel; McKenna, Christopher

    2012-11-01

    The development and interaction of hairpin vortices are examined and categorized to better understand their role in fully turbulent boundary layers. Hairpin vortices are generated within an otherwise laminar boundary layer using a free surface water channel. Direct injection is the primary generation method and the behavior of the vortices is first examined using flow visualization. Hydrogen bubble wire is combined with dye injection to help clarify the role of the vorticity in the fluid immediately surrounding the hairpin vortex. PIV data is also used to classify the development and maturity of the vortices for a range of free stream and injection conditions. The interactions of two hairpin vortices of varying maturity are characterized to investigate the potential mechanisms for the formation of hairpin packets beyond autogeneration. Finally, the behavior of hairpin vortices generated with a new technique that uses a transient hemispherical protrusion is also examined. Supported by the National Science Foundation under Grant CBET-1040236.

  1. Generation of mouse and human dendritic cells in vitro.

    PubMed

    Guo, Xueheng; Zhou, Yifan; Wu, Tao; Zhu, Xinyi; Lai, Wenlong; Wu, Li

    2016-05-01

    Dendritic cells (DC) that can orchestrate immune responses and maintain host homeostasis, are indispensable components of the immune system. Although distributed widely in many lymphoid and non-lymphoid tissues, their rarity in number has become a limiting factor for DC related research and therapies. Therefore, methods for efficiently generating large numbers of DC resembling their in vivo counterparts are urgently needed for DC related research and therapies. Herein we summarize the current methods for generating mouse and human DC in vitro and hope that these will facilitate both studies of DC biology and their clinical applications.

  2. UWB SAR system PULSAR: new generator and antenna developments

    NASA Astrophysics Data System (ADS)

    Delmonte, Philippe; Dubois, Cyril; Andrieu, Jo"l.; Beillard, Bruno; Lalande, Michèle; Bertrand, Valérie; Jecko, Bernard; Pecastaing, Laurent; Gibert, Alain; Paillol, Jean; Domens, Pierre; Guillerey, Régis; Monnier, Francis; Legoff, Marc

    2003-08-01

    PULSAR is an Ultra Wide-Band short pulse Radar developed by the CELAR (French Technical Centre for Armament Electronics) and the IRCOM (Research Institute of Microwave and Optical Communications) in order to detect foliage and ground concealed targets. One of the most promising mission of such potential radar is the detection of buried and surface land mine fields. An instrumentation measurement system has been designed and implemented. This paper deals with the recent development efforts on this system, specially on a new pulse generator and a new UWB antenna. Recently, the LGE (Laboratoire de Génie Electrique) has developed a high voltage pulse coaxial generator. These recent developments allowed to increase the pulse output voltage and the pulse rise time. The new UWB antenna is able to support a very high voltage; the bandwidth and the gain are greater than the ones of the previous antenna.

  3. Beyond Idea Generation: The Power of Groups in Developing Ideas

    ERIC Educational Resources Information Center

    McMahon, Kibby; Ruggeri, Azzurra; Kämmer, Juliane E.; Katsikopoulos, Konstantinos V.

    2016-01-01

    Brainstorming research has claimed that individuals are more creative than groups. However, these conclusions are largely based on measuring creativity by the number of ideas generated, and researchers have tended to neglect other important components of creativity, such as the quality of developed ideas. These studies aim to address this gap in…

  4. Thermoelectric Materials Development for Low Temperature Geothermal Power Generation

    DOE Data Explorer

    Tim Hansen

    2016-01-29

    Data includes characterization results for novel thermoelectric materials developed specifically for power generation from low temperature geothermal brines. Materials characterization data includes material density, thickness, resistance, Seebeck coefficient. This research was carried out by Novus Energy Partners in Cooperation with Southern Research Institute for a Department of Energy Sponsored Project.

  5. Development and Design of a Dynamic Multimedia Item Generation Mechanism

    ERIC Educational Resources Information Center

    Weng, Ting-Sheng

    2012-01-01

    This research applies multimedia technology to design a dynamic item generation method that can adaptively adjust the difficulty level of items according to the level of the testee. The method is based on interactive testing software developed by Flash Actionscript, and provides a testing solution for users by automatically distributing items of…

  6. Beyond Idea Generation: The Power of Groups in Developing Ideas

    ERIC Educational Resources Information Center

    McMahon, Kibby; Ruggeri, Azzurra; Kämmer, Juliane E.; Katsikopoulos, Konstantinos V.

    2016-01-01

    Brainstorming research has claimed that individuals are more creative than groups. However, these conclusions are largely based on measuring creativity by the number of ideas generated, and researchers have tended to neglect other important components of creativity, such as the quality of developed ideas. These studies aim to address this gap in…

  7. Development and Design of a Dynamic Multimedia Item Generation Mechanism

    ERIC Educational Resources Information Center

    Weng, Ting-Sheng

    2012-01-01

    This research applies multimedia technology to design a dynamic item generation method that can adaptively adjust the difficulty level of items according to the level of the testee. The method is based on interactive testing software developed by Flash Actionscript, and provides a testing solution for users by automatically distributing items of…

  8. Development and Testing of Next Generation AWACS SF Processing

    DTIC Science & Technology

    1999-01-01

    dimensional assignment problems could be generalized to n- dimensions, then it would solve the tracking sensor fusion problem. Although the true n...Dates Covered (from... to) ("DD MON YYYY") Title and Subtitle Development and Testing of Next Generation AWACS SF Processing Contract or Grant

  9. RICOR development of the next generation highly reliable rotary cryocooler

    NASA Astrophysics Data System (ADS)

    Regev, Itai; Nachman, Ilan; Livni, Dorit; Riabzev, Sergey; Filis, Avishai; Segal, Victor

    2016-05-01

    Early rotary cryocoolers were designed for the lifetime of a few thousands operating hours. Ricor K506 model's life expectancy was only 5,000 hours, then the next generation K508 model was designed to achieve 10,000 operating hours in basic conditions, while the modern K508N was designed for 20,000 operating hours. Nowadays, the new challenges in the field of rotary cryocoolers require development of a new generation cooler that could compete with the linear cryocooler reliability, achieving the lifetime goal of 30,000 operating hours, and even more. Such new advanced cryocooler can be used for upgrade existing systems, or to serve the new generation of high-temperature detectors that are currently under development, enabling the cryocooler to work more efficiently in the field. The improvement of the rotary cryocooler reliability is based on a deep analysis and understating of the root failure causes, finding solutions to reduce bearings wear, using modern materials and lubricants. All of those were taken into consideration during the development of the new generation rotary coolers. As a part of reliability challenges, new digital controller was also developed, which allows new options, such as discrete control of the operating frequency, and can extend the cooler operating hours due to new controlling technique. In addition, the digital controller will be able to collect data during cryocooler operation, aiming end of life prediction.

  10. Generativity-Stagnation: Development of a Status Model.

    ERIC Educational Resources Information Center

    Bradley, Cheryl L.

    1997-01-01

    Reviews theoretical and empirical developments in Erik Erikson's construct of generativity-stagnation. Presents a five-category model describing styles of resolving the issue using combinations of level of involvement or active concern for the growth of self and others; and level of inclusivity or scope of caregiving concern. Discusses model in…

  11. Generating and Implementing School Based Management of Program Development.

    ERIC Educational Resources Information Center

    Moeller, Jean

    Described are the efforts of generating and implementing a generic model for program development at a kindergarten through sixth-grade elementary school in order to satisfy identified needs for program improvements in science. The implementation of the program involved a steering committee, the teaching staff, community members and external…

  12. A novel microbial fuel cell and photobioreactor system for continuous domestic wastewater treatment and bioelectricity generation.

    PubMed

    Jiang, Haiming; Luo, Shengjun; Shi, Xiaoshuang; Dai, Meng; Guo, Rong-Bo

    2012-07-01

    A system containing a sequential anode-cathode configuration microbial fuel cell and a photobioreactor was developed for continuous treatment of wastewater and electricity generation. Wastewater was treated by the fuel cell to decrease the chemical oxygen demand (COD), phosphorus and nitrogen and to produce electricity. The effluent from the cathode compartment of the cell was continuously fed to an external photobioreactor to remove the remaining P and N using microalgae. Alone, the fuel cell generated a maximum power of 20.3 W/m(3) and achieved removal of 85 % COD, 58 % total phosphorus (TP) and 91 % NH(4) (+)-N. When coupled with the photobioreactor, the system removed 92 % TP and 99 % NH(4) (+)-N. These results demonstrate both the effectiveness and the potential application of the coupled system to continuously treat domestic wastewater and simultaneously generate electricity.

  13. Development of alkaline fuel cells.

    SciTech Connect

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov

    2013-09-01

    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassovs research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herrings group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

  14. Development of concentrator solar cells

    SciTech Connect

    Not Available

    1994-08-01

    A limited pilot production run on PESC silicon solar cells for use at high concentrations (200 to 400 suns) is summarized. The front contact design of the cells was modified for operation without prismatic covers. The original objective of the contract was to systematically complete a process consolidation phase, in which all the, process improvements developed during the contract would be combined in a pilot production run. This pilot run was going to provide, a basis for estimating cell costs when produced at high throughput. Because of DOE funding limitations, the Photovoltaic Concentrator Initiative is on hold, and Applied Solar`s contract was operated at a low level of effort for most of 1993. The results obtained from the reduced scope pilot run showed the effects of discontinuous process optimization and characterization. However, the run provided valuable insight into the technical areas that can be optimized to achieve the original goals of the contract.

  15. Generation of pattern and form in the developing limb.

    PubMed

    Towers, Matthew; Tickle, Cheryll

    2009-01-01

    The developing limb is a major model for pattern formation in vertebrate embryos. Many of the seminal discoveries of the mechanisms involved in patterning have been made using chick embryos because of the ease of manipulating their developing limbs. More recently, the molecular basis of limb pattern formation has been increasingly uncovered and now, with the availability of genomic resources, the genetic approaches available are even more powerful. Nevertheless, since the limb is ultimately built of cells, gene action must ultimately be translated into cell behaviour and a major challenge will be to integrate genetics with molecular and cellular biology. In this review, we will first outline the stages in limb development, the major interacting signalling pathways that pattern the limb and the molecules involved. We will describe fate maps of the developing limb, and discuss what is known about cellular activities including proliferation, death, adhesiveness, communication and migration during the patterning process. Finally we will explore how these cell activities produce form.

  16. Generation of L cells in mouse and human small intestine organoids.

    PubMed

    Petersen, Natalia; Reimann, Frank; Bartfeld, Sina; Farin, Henner F; Ringnalda, Femke C; Vries, Robert G J; van den Brink, Stieneke; Clevers, Hans; Gribble, Fiona M; de Koning, Eelco J P

    2014-02-01

    Upon a nutrient challenge, L cells produce glucagon-like peptide 1 (GLP-1), a powerful stimulant of insulin release. Strategies to augment endogenous GLP-1 production include promoting L-cell differentiation and increasing L-cell number. Here we present a novel in vitro platform to generate functional L cells from three-dimensional cultures of mouse and human intestinal crypts. We show that short-chain fatty acids selectively increase the number of L cells, resulting in an elevation of GLP-1 release. This is accompanied by the upregulation of transcription factors associated with the endocrine lineage of intestinal stem cell development. Thus, our platform allows us to study and modulate the development of L cells in mouse and human crypts as a potential basis for novel therapeutic strategies in patients with type 2 diabetes.

  17. Epithelial cell guidance by self-generated EGF gradients†

    PubMed Central

    Scherber, Cally; Aranyosi, Alexander J.; Kulemann, Birte; Thayer, Sarah P.; Toner, Mehmet; Iliopoulos, Othon

    2012-01-01

    Cancer epithelial cells often migrate away from the primary tumor to invade into the surrounding tissues. Their migration is commonly assumed to be directed by pre-existent spatial gradients of chemokines and growth factors in the target tissues. Unexpectedly however, we found that the guided migration of epithelial cells is possible in vitro in the absence of pre-existent chemical gradients. We observed that both normal and cancer epithelial cells can migrate persistently and reach the exit along the shortest path from microscopic mazes filled with uniform concentrations of media. Using microscale engineering techniques and biophysical models, we uncovered a self-guidance strategy during which epithelial cells generate their own guiding cues under conditions of biochemical confinement. The self-guidance strategy depends on the balance between three interdependent processes: epidermal growth factor (EGF) uptake by the cells (U), the restricted transport of EGF through the structured microenvironment (T), and cell chemotaxis toward the resultant EGF gradients (C). The UTC self-guidance strategy can be perturbed by inhibition of signalling through EGF-receptors and appears to be independent from chemokine signalling. Better understanding of the UTC self-guidance strategy could eventually help devise new ways for modulating epithelial cell migration and delaying cancer cell invasion or accelerating wound healing. PMID:22314635

  18. Microfluidic geometric metering-based multi-reagent mixture generator for robust live cell screening array.

    PubMed

    Wang, Han; Kim, Jeongyun; Jayaraman, Arul; Han, Arum

    2014-12-01

    Microfluidic live cell arrays with integrated concentration gradient or mixture generators have been utilized in screening cellular responses to various biomolecular cues. Microfluidic network-based gradient generators that can create concentration gradients by repeatedly splitting and mixing different solutions using networks of serpentine channels are commonly used. However, in this method the generation of concentration gradients relies on the continuous flow of sample solutions at optimized flow rates, which poses challenges in maintaining the pressure and flow stability throughout the entire assay period. Here we present a microfluidic live cell screening array with an on-demand multi-reagent mixture generator where the mixing ratios, thus generated concentrations, are hard-wired into the chip itself through a geometric metering method. This platform showed significantly improved robustness and repeatability in generating concentration gradients of fluorescent dyes (average coefficient of variance C.V. = 9 %) compared to the conventional network-based gradient generators (average C.V. = 21 %). In studying the concentration dependent effects of the environmental toxicant 3-methylcholanthrene (3MC) on the activation of cytochrome P450 1A1 (Cyp 1A1) enzyme in H4IIE rat hepatoma cells, statistical variation of the Cyp 1A1 response was significantly lower (C.V. = 5 %) when using the developed mixture generator compared to that using the conventional gradient generator (C.V. = 12 %). Reduction in reagent consumption by 12-times was also achieved. This robust, accurate, and scalable multi-reagent mixture generator integrated with a cell culture array as a live cell assay platform can be readily implemented into various screening applications where repeatability, robustness, and low reagent consumptions over long periods of assay time are of importance.

  19. Generation and identification of tumor-evoked regulatory B cells

    PubMed Central

    Biragyn, Arya; Lee-Chang, Catalina; Bodogai, Monica

    2014-01-01

    The involvement of Bregs in cancer remains poorly understood despite their well-documented regulation of responses to the self and protection from harmful autoimmunity. We recently discovered a unique regulatory B cell subset evoked by breast cancer to mediate protection of metastasizing cancer cells. These results together with the wealth of findings of the last 40 years on B cells in tumorigenesis suggest the existence of additional cancer Bregs modulating anticancer responses. To facilitate the search for them, here we provide our detailed protocol for the characterization and generation of tumor-evoked regulatory B cells. Wherever applicable, we also discuss nuances and uniqueness of a Breg study in cancer to warn potential pitfalls. PMID:25015287

  20. Development of a circuit breaker for large generators. Final report

    SciTech Connect

    Garzon, R.D.; Wu, J.L.

    1982-01-01

    This report deals with the evaluation of design concepts for the development of Circuit Breakers for large generators and attempts to define a rating structure for a generator circuit breaker. It includes studies on the influence of the system upon the performance of the circuit breaker. This study covers: The harmonic content in the fault current, the absence of current zeros, the influence of the dynamics of the generator shaft upon the current, and the magnitude and characteristics of the inherent transient recovery voltage produced by the system. Design requirements such as storage volumes, operating pressures and size of nozzle's orifice are identified for SF/sub 6/ synchronous and non synchronous interrupters of the axial flow type. The concept of a current limiting generator circuit breaker is introduced and two variations of a current limiting element are evaluated. One of the concepts uses liquid metal (NaK 78) as the current limiting element, and the other considers the use of a frangible conductor. The preliminary results obtained with an experimental model of a NaK device shows that a magnetic pinching effect reduces the time required for the initiation of the liquid metal vaporization which determines the onset of current limitation and shows that the NaK device appears to offer promise for the development of a current limiting generator breaker.

  1. An Abbreviated Protocol for In Vitro Generation of Functional Human Embryonic Stem Cell-Derived Beta-Like Cells

    PubMed Central

    Massumi, Mohammad; Pourasgari, Farzaneh; Nalla, Amarnadh; Batchuluun, Battsetseg; Nagy, Kristina; Neely, Eric; Gull, Rida; Nagy, Andras; Wheeler, Michael B.

    2016-01-01

    The ability to yield glucose-responsive pancreatic beta-cells from human pluripotent stem cells in vitro will facilitate the development of the cell replacement therapies for the treatment of Type 1 Diabetes. Here, through the sequential in vitro targeting of selected signaling pathways, we have developed an abbreviated five-stage protocol (25–30 days) to generate human Embryonic Stem Cell-Derived Beta-like Cells (ES-DBCs). We showed that Geltrex, as an extracellular matrix, could support the generation of ES-DBCs more efficiently than that of the previously described culture systems. The activation of FGF and Retinoic Acid along with the inhibition of BMP, SHH and TGF-beta led to the generation of 75% NKX6.1+/NGN3+ Endocrine Progenitors. The inhibition of Notch and tyrosine kinase receptor AXL, and the treatment with Exendin-4 and T3 in the final stage resulted in 35% mono-hormonal insulin positive cells, 1% insulin and glucagon positive cells and 30% insulin and NKX6.1 co-expressing cells. Functionally, ES-DBCs were responsive to high glucose in static incubation and perifusion studies, and could secrete insulin in response to successive glucose stimulations. Mitochondrial metabolic flux analyses using Seahorse demonstrated that the ES-DBCs could efficiently metabolize glucose and generate intracellular signals to trigger insulin secretion. In conclusion, targeting selected signaling pathways for 25–30 days was sufficient to generate ES-DBCs in vitro. The ability of ES-DBCs to secrete insulin in response to glucose renders them a promising model for the in vitro screening of drugs, small molecules or genes that may have potential to influence beta-cell function. PMID:27755557

  2. [Cell membrane electroporator with digital generation of random shaped pulses].

    PubMed

    Iakovenko, S A; Trubitsin, B V

    2003-01-01

    A Digital Poration System (DPS), a versatile device for electrotreatment of biological objects by electric field pulses; was designed, constructed, and implemented. A feature distinguishing DPS from the currently available electroporators based on capacitor discharge through the load is the use of a digital-to-analog converter card as a generator of pulses applied for electroporation of biological membranes, with further amplification of the pulse by both voltage and current. The shape of pulses, including bipolar pulses, is arbitrarily programmable in DPS unlike other electroporators providing exponentially decaying and square-wave pulses only. Thus, the application area of DPS is substantially extended. In DPS, many of the drawbacks inherent in capacitor electroporators are removed, including the need for an additional external pulse analyzer monitoring and logging the electroporation processes, the necessity to recharge the capacitor before any new pulse, a poor precision of setting and measuring the pulse parameters, the need for an additional generator of long-lasting low-voltage signals for electrophoresis of ions into the porated object, the need for additional AC generators for the alignment of cells before, after, and during electroporation, and the need for an additional microprocessor to control multi-pulse and/or repetitive protocols. DPS provides a slew rate of about 1 V/1 ns required for the electroporation of most mammalian somatic cells, with +/- 250 V output voltage and 500 Ohm load resistance. The application area of DPS is much wider than for the available porators. It includes electrochemotherapy, cell electrofusion, oocyte activation by mimicking calcium waves (the latter two are the crucial components of mammalian organism cloning technology), dielectrophoretic bunching and orientation ordering of cells, sorting of cells, and electrophoresis of charged species into the cells.

  3. Control of cell identity in pancreas development and regeneration.

    PubMed

    Stanger, Ben Z; Hebrok, Matthias

    2013-06-01

    The endocrine and exocrine cells in the adult pancreas are not static, but can change their differentiation state in response to injury or stress. This concept of cells in flux means that there may be ways to generate certain types of cells (such as insulin-producing β-cells) and prevent formation of others (such as transformed neoplastic cells). We review different aspects of cell identity in the pancreas, discussing how cells achieve their identity during embryonic development and maturation, and how this identity remains plastic, even in the adult pancreas.

  4. Third harmonic generation microscopy of cells and tissue organization.

    PubMed

    Weigelin, Bettina; Bakker, Gert-Jan; Friedl, Peter

    2016-01-15

    The interaction of cells within their microenvironmental niche is fundamental to cell migration, positioning, growth and differentiation in order to form and maintain complex tissue organization and function. Third harmonic generation (THG) microscopy is a label-free scatter process that is elicited by water-lipid and water-protein interfaces, including intra- and extracellular membranes, and extracellular matrix structures. In applied life sciences, THG delivers a versatile contrast modality to complement multi-parameter fluorescence, second harmonic generation and fluorescence lifetime microscopy, which allows detection of cellular and molecular cell functions in three-dimensional tissue culture and small animals. In this Commentary, we review the physical and technical basis of THG, and provide considerations for optimal excitation, detection and interpretation of THG signals. We further provide an overview on how THG has versatile applications in cell and tissue research, with a particular focus on analyzing tissue morphogenesis and homeostasis, immune cell function and cancer research, as well as the emerging applicability of THG in clinical practice. © 2016. Published by The Company of Biologists Ltd.

  5. Hydride generation from the Exide load-leveling cells

    NASA Astrophysics Data System (ADS)

    Marr, J. J.; Smaga, J. A.

    1987-05-01

    Stibine and arsine evolution from lead-acid cells in a 36-kWh Exide load-leveling module was measured as this module approached 1900 cycles of operation. A gas-collection apparatus enabled us to determine the maximum and average rates for evolution of both toxic hydrides. Hydride generation began once the cell voltage exceeded 2.4 V. The maximum rate for arsine occurred just above 2.5 V and consistently preceded the peak rate for stibine for each sampled cell. The average rates of hydride generation were found to be 175 g/min for stibine and 12.6 g/min for arsine. The former rate proved to be the critical value in determining safe ventilation requirements for cell off-gases. The minimum airflow requirement was calculated to be 340 L/min per cell. Projections for a hypothetical 1-MWh Exide battery without an abatement system indicated that the normal ventilation capacity in the Battery Energy Storage Test facility provides nearly five times the airflow needed for safe hydride removal.

  6. Generation of living cell arrays for atomic force microscopy studies.

    PubMed

    Formosa, Cécile; Pillet, Flavien; Schiavone, Marion; Duval, Raphaël E; Ressier, Laurence; Dague, Etienne

    2015-01-01

    Atomic force microscopy (AFM) is a useful tool for studying the morphology or the nanomechanical and adhesive properties of live microorganisms under physiological conditions. However, to perform AFM imaging, living cells must be immobilized firmly enough to withstand the lateral forces exerted by the scanning tip, but without denaturing them. This protocol describes how to immobilize living cells, ranging from spores of bacteria to yeast cells, into polydimethylsiloxane (PDMS) stamps, with no chemical or physical denaturation. This protocol generates arrays of living cells, allowing statistically relevant measurements to be obtained from AFM measurements, which can increase the relevance of results. The first step of the protocol is to generate a microstructured silicon master, from which many microstructured PDMS stamps can be replicated. Living cells are finally assembled into the microstructures of these PDMS stamps using a convective and capillary assembly. The complete procedure can be performed in 1 week, although the first step is done only once, and thus repeats can be completed within 1 d.

  7. De novo Generation of Cells within Human Nurse Macrophages and Consequences following HIV-1 Infection

    PubMed Central

    Gartner, Suzanne

    2012-01-01

    Nurse cells are defined as those that provide for the development of other cells. We report here, that in vitro, human monocyte-derived macrophages can behave as nurse cells with functional capabilities that include de novo generation of CD4+ T-lymphocytes and a previously unknown small cell with monocytoid characteristics. We named these novel cells “self-renewing monocytoid cells” (SRMC), because they could develop into nurse macrophages that produced another generation of SRMC. SRMC were not detectable in blood. Their transition to nurse behavior was characterized by expression of CD10, a marker of thymic epithelium and bone marrow stroma, typically absent on macrophages. Bromodeoxyuridine labeling and immunostaining for cdc6 expression confirmed DNA synthesis within nurse macrophages. T-cell excision circles were detected in macrophages, along with expression of pre-T-cell receptor alpha and recombination activating gene 1, suggesting that genetic recombination events associated with generation of the T-cell receptor were occurring in these cells. SRMC expressed CCR5, the coreceptor for R5 HIV-1 isolates, and were highly susceptible to HIV-1 entry leading to productive infection. While expressing HIV-1, SRMC could differentiate into nurse macrophages that produced another generation of HIV-1-expressing SRMC. The infected nurse macrophage/SRMC cycle could continue in vitro for multiple generations, suggesting it might represent a mechanism whereby HIV-1 can maintain persistence in vivo. HIV-1 infection of nurse macrophages led to a decline in CD4+ T-cell production. There was severe, preferential loss of the CCR5+ CD4+ T-cell subpopulation. Confocal microscopy revealed individual HIV-1-expressing nurse macrophages simultaneously producing both HIV-1-expressing SRMC and non-expressing CD3+ cells, suggesting that nurse macrophages might be a source of latently infected CD4+ T-cells. Real-time PCR experiments confirmed this by demonstrating 10-fold more HIV-1

  8. Lgr5-Positive Supporting Cells Generate New Hair Cells in the Postnatal Cochlea

    PubMed Central

    Bramhall, Naomi F.; Shi, Fuxin; Arnold, Katrin; Hochedlinger, Konrad; Edge, Albert S.B.

    2014-01-01

    Summary The prevalence of hearing loss after damage to the mammalian cochlea has been thought to be due to a lack of spontaneous regeneration of hair cells, the primary receptor cells for sound. Here, we show that supporting cells, which surround hair cells in the normal cochlear epithelium, differentiate into new hair cells in the neonatal mouse following ototoxic damage. Using lineage tracing, we show that new hair cells, predominantly outer hair cells, arise from Lgr5-expressing inner pillar and third Deiters cells and that new hair cell generation is increased by pharmacological inhibition of Notch. These data suggest that the neonatal mammalian cochlea has some capacity for hair cell regeneration following damage alone and that Lgr5-positive cells act as hair cell progenitors in the cochlea. PMID:24672754

  9. Stromelysin generates a fibronectin fragment that inhibits Schwann cell proliferation

    PubMed Central

    1992-01-01

    Our previous report (Muir, D., S. Varon, and M. Manthorpe. 1990. J. Cell Biol. 109:2663-2672) described the isolation and partial characterization of a 55-kD antiproliferative protein found in Schwann cell (SC) and schwannoma cell line-conditioned media and we concluded that SC proliferation is under negative autocrine control. In the present study the 55-kD protein was found to possess metalloprotease activity and stromelysin immunoreactivity. The SC-derived metalloprotease shares many properties with stromelysin isolated from other sources including the ability to cleave fibronectin (FN). Furthermore, limited proteolysis of FN by the SC-derived protease generated a FN fragment which itself expresses a potent antiproliferative activity for SCs. The active FN fragment corresponds to the 29-kD amino-terminal region of the FN molecule which was also identified as an active component in SC CM. Additional evidence that a proteolytic fragment of FN can possess antiproliferative activity for SCs was provided by the finding that plasmin can generate an amino- terminal FN fragment which mimicked the activity of the SC metalloprotease-generated antiproliferative FN fragment. Both the 55-kD SC metalloprotease and the 29-kD FN fragment could completely and reversibly inhibit proliferation of SCs treated with various mitogens and both were largely ineffective at inhibiting proliferation by immortalized or transformed SC lines. Normal and transformed SC types do secrete the proform of stromelysin, however, transformed cultures do not produce activated stromelysin and thus cannot generate the antiproliferative fragment of FN. These results suggest that, once activated, a SC-derived protease similar to stromelysin cleaves FN and generates an antiproliferative activity which can maintain normal SC quiescence in vitro. PMID:1730742

  10. [Development of multi-function ECG signal generator].

    PubMed

    Cheng, F; Wei, Y X

    2000-07-01

    This paper describes the development of a portable multi-function ECG signal generator, which is based on micro-controller. It uses technique of LCD screen, and realizes man-machine interaction by keyboard. In constructing and disposing data module of the ECG signal, Eigen-heartbeat Code mapping method gets ROM saved greatly. Therefore it can generate all kinds of user-defined ECG signal sequence with no extension of on-board memory chips. This system can also simulate kinds of ECG signals, which have various heart rates and symptoms. It can meet the needs of researching and maintenance of kinds of ECG instruments.

  11. Generation of Induced Pluripotent Stem Cells from Mammalian Endangered Species.

    PubMed

    Ben-Nun, Inbar Friedrich; Montague, Susanne C; Houck, Marlys L; Ryder, Oliver; Loring, Jeanne F

    2015-01-01

    For some highly endangered species there are too few reproductively capable animals to maintain adequate genetic diversity, and extraordinary measures are necessary to prevent their extinction. Cellular reprogramming is a means to capture the genomes of individual animals as induced pluripotent stem cells (iPSCs), which may eventually facilitate reintroduction of genetic material into breeding populations. Here, we describe a method for generating iPSCs from fibroblasts of mammalian endangered species.

  12. A Bio-Based Fuel Cell for Distributed Energy Generation

    SciTech Connect

    Anthony Terrinoni; Sean Gifford

    2008-06-30

    The technology we propose consists primarily of an improved design for increasing the energy density of a certain class of bio-fuel cell (BFC). The BFCs we consider are those which harvest electrons produced by microorganisms during their metabolism of organic substrates (e.g. glucose, acetate). We estimate that our technology will significantly enhance power production (per unit volume) of these BFCs, to the point where they could be employed as stand-alone systems for distributed energy generation.

  13. Deployable Fuel Cell Power Generator - Multi-Fuel Processor

    DTIC Science & Technology

    2009-02-01

    nationals. Copies may be obtained from the Defense Technical Information Center (DTIC) (http://www.dtic.mil). REPORT NUMBER AFRL-RX-TY-TR-2008-4607 HAS...This report is published in the interest of scientific and technical information exchange, and its publication does not constitute the...introduction of more efficient and quiet fuel cell electric generators into power applications. This report describes the demonstration of the direct

  14. Preventing hypoxia-induced cell death in beta cells and islets via hydrolytically activated, oxygen-generating biomaterials

    PubMed Central

    Pedraza, Eileen; Coronel, Maria M.; Fraker, Christopher A.; Ricordi, Camillo; Stabler, Cherie L.

    2012-01-01

    A major hindrance in engineering tissues containing highly metabolically active cells is the insufficient oxygenation of these implants, which results in dying or dysfunctional cells in portions of the graft. The development of methods to increase oxygen availability within tissue-engineered implants, particularly during the early engraftment period, would serve to allay hypoxia-induced cell death. Herein, we designed and developed a hydrolytically activated oxygen-generating biomaterial in the form of polydimethylsiloxane (PDMS)-encapsulated solid calcium peroxide, PDMS-CaO2. Encapsulation of solid peroxide within hydrophobic PDMS resulted in sustained oxygen generation, whereby a single disk generated oxygen for more than 6 wk at an average rate of 0.026 mM per day. The ability of this oxygen-generating material to support cell survival was evaluated using a β cell line and pancreatic rat islets. The presence of a single PDMS-CaO2 disk eliminated hypoxia-induced cell dysfunction and death for both cell types, resulting in metabolic function and glucose-dependent insulin secretion comparable to that in normoxic controls. A single PDMS-CaO2 disk also sustained enhanced β cell proliferation for more than 3 wk under hypoxic culture conditions. Incorporation of these materials within 3D constructs illustrated the benefits of these materials to prevent the development of detrimental oxygen gradients within large implants. Mathematical simulations permitted accurate prediction of oxygen gradients within 3D constructs and highlighted conditions under which supplementation of oxygen tension would serve to benefit cellular viability. Given the generality of this platform, the translation of these materials to other cell-based implants, as well as ischemic tissues in general, is envisioned. PMID:22371586

  15. Monolithic solid oxide fuel cell technology advancement for coal-based power generation

    SciTech Connect

    Not Available

    1992-04-14

    The program is conducted by a team consisting of AiResearch Los Angeles Division of Allied-Signal Aerospace Company and Argonne National Laboratory (ANL). The objective of the program is to advance materials and fabrication methodologies to develop a monolithic solid oxide fuel cell (MSOFC) system capable of meeting performance, life, and cost goals for coal-based power generation. The program focuses on materials research and development, fabrication process development, cell/stack performance testing and characterization, cost and system analysis, and quality development.

  16. Solid oxide fuel cell generator with removable modular fuel cell stack configurations

    DOEpatents

    Gillett, James E.; Dederer, Jeffrey T.; Zafred, Paolo R.; Collie, Jeffrey C.

    1998-01-01

    A high temperature solid oxide fuel cell generator produces electrical power from oxidation of hydrocarbon fuel gases such as natural gas, or conditioned fuel gases, such as carbon monoxide or hydrogen, with oxidant gases, such as air or oxygen. This electrochemical reaction occurs in a plurality of electrically connected solid oxide fuel cells bundled and arrayed in a unitary modular fuel cell stack disposed in a compartment in the generator container. The use of a unitary modular fuel cell stack in a generator is similar in concept to that of a removable battery. The fuel cell stack is provided in a pre-assembled self-supporting configuration where the fuel cells are mounted to a common structural base having surrounding side walls defining a chamber. Associated generator equipment may also be mounted to the fuel cell stack configuration to be integral therewith, such as a fuel and oxidant supply and distribution systems, fuel reformation systems, fuel cell support systems, combustion, exhaust and spent fuel recirculation systems, and the like. The pre-assembled self-supporting fuel cell stack arrangement allows for easier assembly, installation, maintenance, better structural support and longer life of the fuel cells contained in the fuel cell stack.

  17. Solid oxide fuel cell generator with removable modular fuel cell stack configurations

    DOEpatents

    Gillett, J.E.; Dederer, J.T.; Zafred, P.R.; Collie, J.C.

    1998-04-21

    A high temperature solid oxide fuel cell generator produces electrical power from oxidation of hydrocarbon fuel gases such as natural gas, or conditioned fuel gases, such as carbon monoxide or hydrogen, with oxidant gases, such as air or oxygen. This electrochemical reaction occurs in a plurality of electrically connected solid oxide fuel cells bundled and arrayed in a unitary modular fuel cell stack disposed in a compartment in the generator container. The use of a unitary modular fuel cell stack in a generator is similar in concept to that of a removable battery. The fuel cell stack is provided in a pre-assembled self-supporting configuration where the fuel cells are mounted to a common structural base having surrounding side walls defining a chamber. Associated generator equipment may also be mounted to the fuel cell stack configuration to be integral therewith, such as a fuel and oxidant supply and distribution systems, fuel reformation systems, fuel cell support systems, combustion, exhaust and spent fuel recirculation systems, and the like. The pre-assembled self-supporting fuel cell stack arrangement allows for easier assembly, installation, maintenance, better structural support and longer life of the fuel cells contained in the fuel cell stack. 8 figs.

  18. Generation of functional platelets from canine induced pluripotent stem cells.

    PubMed

    Nishimura, Toshiya; Hatoya, Shingo; Kanegi, Ryoji; Sugiura, Kikuya; Wijewardana, Viskam; Kuwamura, Mitsuru; Tanaka, Miyuu; Yamate, Jyoji; Izawa, Takeshi; Takahashi, Masahiro; Kawate, Noritoshi; Tamada, Hiromichi; Imai, Hiroshi; Inaba, Toshio

    2013-07-15

    Thrombocytopenia (TTP) is a blood disease common to canines and human beings. Currently, there is no valid therapy for this disease except blood transfusion. In this study, we report the generation of canine induced pluripotent stem cells (ciPSCs) from canine embryonic fibroblasts, and a novel protocol for creating mature megakaryocytes (MKs) and functional platelets from ciPSCs. The ciPSCs were generated using lentiviral vectors, and differentiated into MKs and platelets on OP9 stromal cells supplemented with growth factors. Our ciPSCs presented in a tightly domed shape and showed expression of a critical pluripotency marker, REX1, and normal karyotype. Additionally, ciPSCs differentiated into cells derived from three germ layers via the formation of an embryoid body. The MKs derived from ciPSCs had hyperploidy and transformed into proplatelets. The proplatelets released platelets early on that expressed specific MK and platelet marker CD41/61. Interestingly, these platelets, when activated with adenosine diphosphate or thrombin, bind to fibrinogen. Moreover, electron microscopy showed that the platelets had the same ultrastructure as peripheral platelets. Thus, we have demonstrated for the first time the generation of ciPSCs that are capable of differentiating into MKs and release functional platelets in vitro. Our system for differentiating ciPSCs into MKs and platelets promises a critical therapy for canine TTP and appears to be extensible in principle to resolve human TTP.

  19. Defined and Scalable Generation of Hepatocyte-like Cells from Human Pluripotent Stem Cells.

    PubMed

    Wang, Yu; Alhaque, Sharmin; Cameron, Kate; Meseguer-Ripolles, Jose; Lucendo-Villarin, Baltasar; Rashidi, Hassan; Hay, David C

    2017-03-02

    Human pluripotent stem cells (hPSCs) possess great value for biomedical research. hPSCs can be scaled and differentiated to all cell types found in the human body. The differentiation of hPSCs to human hepatocyte-like cells (HLCs) has been extensively studied, and efficient differentiation protocols have been established. The combination of extracellular matrix and biological stimuli, including growth factors, cytokines, and small molecules, have made it possible to generate HLCs that resemble primary human hepatocytes. However, the majority of procedures still employ undefined components, giving rise to batch-to-batch variation. This serves as a significant barrier to the application of the technology. To tackle this issue, we developed a defined system for hepatocyte differentiation using human recombinant laminins as extracellular matrices in combination with a serum-free differentiation process. Highly efficient hepatocyte specification was achieved, with demonstrated improvements in both HLC function and phenotype. Importantly, this system is easy to scale up using research and GMP-grade hPSC lines promising advances in cell-based modelling and therapies.

  20. Lung-resident tissue macrophages generate Foxp3+ regulatory T cells and promote airway tolerance

    PubMed Central

    Soroosh, Pejman; Doherty, Taylor A.; Duan, Wei; Mehta, Amit Kumar; Choi, Heonsik; Adams, Yan Fei; Mikulski, Zbigniew; Khorram, Naseem; Rosenthal, Peter; Broide, David H.

    2013-01-01

    Airway tolerance is the usual outcome of inhalation of harmless antigens. Although T cell deletion and anergy are likely components of tolerogenic mechanisms in the lung, increasing evidence indicates that antigen-specific regulatory T cells (inducible Treg cells [iTreg cells]) that express Foxp3 are also critical. Several lung antigen-presenting cells have been suggested to contribute to tolerance, including alveolar macrophages (MØs), classical dendritic cells (DCs), and plasmacytoid DCs, but whether these possess the attributes required to directly promote the development of Foxp3+ iTreg cells is unclear. Here, we show that lung-resident tissue MØs coexpress TGF-β and retinal dehydrogenases (RALDH1 and RALDH 2) under steady-state conditions and that their sampling of harmless airborne antigen and presentation to antigen-specific CD4 T cells resulted in the generation of Foxp3+ Treg cells. Treg cell induction in this model depended on both TGF-β and retinoic acid. Transfer of the antigen-pulsed tissue MØs into the airways correspondingly prevented the development of asthmatic lung inflammation upon subsequent challenge with antigen. Moreover, exposure of lung tissue MØs to allergens suppressed their ability to generate iTreg cells coincident with blocking airway tolerance. Suppression of Treg cell generation required proteases and TLR-mediated signals. Therefore, lung-resident tissue MØs have regulatory functions, and strategies to target these cells might hold promise for prevention or treatment of allergic asthma. PMID:23547101

  1. The design and development of a third generation OSEE instrument

    NASA Astrophysics Data System (ADS)

    Perey, D. F.; Yost, W. T.; Stone, F. D.; Welch, C. S.; Scales, E.; Gasser, E. S.; Joe, E.; Goodman, T.; Pascual, X.; Hefner, B.

    1995-03-01

    Optically Stimulated Electron Emission (OSEE) has been used to quantify surface contamination in the aerospace community. As advances are made towards the understanding of OSEE, it is desirable to incorporate technological advances with succeeding generations of instrumentation, so that improvements in the practical application of OSEE may be disseminated among the user community. Several studies undertaken by Yost, Welch, Abedin and others have expanded the knowledge base related to the underlying principles of OSEE. The conclusions of these studies, together with inputs from the user community were the foundation upon which the development of a third generation OSEE instrument was based. This manuscript describes the significant improvements incorporated into a third generation OSEE instrument as well as the elements unique to its design.

  2. The design and development of a third generation OSEE instrument

    NASA Technical Reports Server (NTRS)

    Perey, D. F.; Yost, W. T.; Stone, F. D.; Welch, C. S.; Scales, E.; Gasser, E. S.; Joe, E.; Goodman, T.; Pascual, X.; Hefner, B.

    1995-01-01

    Optically Stimulated Electron Emission (OSEE) has been used to quantify surface contamination in the aerospace community. As advances are made towards the understanding of OSEE, it is desirable to incorporate technological advances with succeeding generations of instrumentation, so that improvements in the practical application of OSEE may be disseminated among the user community. Several studies undertaken by Yost, Welch, Abedin and others have expanded the knowledge base related to the underlying principles of OSEE. The conclusions of these studies, together with inputs from the user community were the foundation upon which the development of a third generation OSEE instrument was based. This manuscript describes the significant improvements incorporated into a third generation OSEE instrument as well as the elements unique to its design.

  3. Thymus medulla fosters generation of natural Treg cells, invariant γδ T cells, and invariant NKT cells: what we learn from intrathymic migration.

    PubMed

    Cowan, Jennifer E; Jenkinson, William E; Anderson, Graham

    2015-03-01

    The organization of the thymus into distinct cortical and medullary regions enables it to control the step-wise migration and development of immature T-cell precursors. Such a process provides access to specialized cortical and medullary thymic epithelial cells at defined stages of maturation, ensuring the generation of self-tolerant and MHC-restricted conventional CD4(+) and CD8(+) αβ T cells. The migratory cues and stromal cell requirements that regulate the development of conventional αβ T cells have been well studied. However, the thymus also fosters the generation of several immunoregulatory T-cell populations that form key components of both innate and adaptive immune responses. These include Foxp3(+) natural regulatory T cells, invariant γδ T cells, and CD1d-restricted invariant natural killer T cells (iNKT cells). While less is known about the intrathymic requirements of these nonconventional T cells, recent studies have highlighted the importance of the thymus medulla in their development. Here, we review recent findings on the mechanisms controlling the intrathymic migration of distinct T-cell subsets, and relate this to knowledge of the microenvironmental requirements of these cells.

  4. Development and Buildup of a Stirling Radioisotope Generator Electrical Simulator

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F.; Krasowski, Michael J.; Greer, Lawrence C.; Flatico, Joseph M.; Spina, Dan C.

    2008-01-01

    This paper describes the development of a Stirling Radioisotope Generator (SRG) Simulator for use in a prototype lunar robotic rover. The SRG developed at NASA Glenn Research Center (GRC) is a promising power source for the robotic exploration of the sunless areas of the moon. The simulator designed provides a power output similar to the SRG output of 5.7 A at 28 Vdc, while using ac wall power as the input power source. The designed electrical simulator provides rover developers the physical and electrical constraints of the SRG supporting parallel development of the SRG and rover. Parallel development allows the rover design team to embrace the SRG s unique constraints while development of the SRG is continued to a flight qualified version.

  5. Hesr1 and Hesr3 are essential to generate undifferentiated quiescent satellite cells and to maintain satellite cell numbers

    PubMed Central

    Fukada, So-ichiro; Yamaguchi, Masahiko; Kokubo, Hiroki; Ogawa, Ryo; Uezumi, Akiyoshi; Yoneda, Tomohiro; Matev, Miroslav M.; Motohashi, Norio; Ito, Takahito; Zolkiewska, Anna; Johnson, Randy L.; Saga, Yumiko; Miyagoe-Suzuki, Yuko; Tsujikawa, Kazutake; Takeda, Shin’ichi; Yamamoto, Hiroshi

    2011-01-01

    Satellite cells, which are skeletal muscle stem cells, divide to provide new myonuclei to growing muscle fibers during postnatal development, and then are maintained in an undifferentiated quiescent state in adult skeletal muscle. This state is considered to be essential for the maintenance of satellite cells, but their molecular regulation is unknown. We show that Hesr1 (Hey1) and Hesr3 (Heyl) (which are known Notch target genes) are expressed simultaneously in skeletal muscle only in satellite cells. In Hesr1 and Hesr3 single-knockout mice, no obvious abnormalities of satellite cells or muscle regenerative potentials are observed. However, the generation of undifferentiated quiescent satellite cells is impaired during postnatal development in Hesr1/3 double-knockout mice. As a result, myogenic (MyoD and myogenin) and proliferative (Ki67) proteins are expressed in adult satellite cells. Consistent with the in vivo results, Hesr1/3-null myoblasts generate very few Pax7+ MyoD– undifferentiated cells in vitro. Furthermore, the satellite cell number gradually decreases in Hesr1/3 double-knockout mice even after it has stabilized in control mice, and an age-dependent regeneration defect is observed. In vivo results suggest that premature differentiation, but not cell death, is the reason for the reduced number of satellite cells in Hesr1/3 double-knockout mice. These results indicate that Hesr1 and Hesr3 are essential for the generation of adult satellite cells and for the maintenance of skeletal muscle homeostasis. PMID:21989910

  6. A xenogeneic-free system generating functional human gut organoids from pluripotent stem cells.

    PubMed

    Uchida, Hajime; Machida, Masakazu; Miura, Takumi; Kawasaki, Tomoyuki; Okazaki, Takuya; Sasaki, Kengo; Sakamoto, Seisuke; Ohuchi, Noriaki; Kasahara, Mureo; Umezawa, Akihiro; Akutsu, Hidenori

    2017-01-12

    Functional intestines are composed of cell types from all 3 primary germ layers and are generated through a highly orchestrated and serial developmental process. Directed differentiation of human pluripotent stem cells (hPSCs) has been shown to yield gut-specific cell types; however, these structures do not reproduce critical functional interactions between cell types of different germ layers. Here, we developed a simple protocol for the generation of mature functional intestinal organoids from hPSCs under xenogeneic-free conditions. The stem cell-derived gut organoids produced here were found to contain distinct types of intestinal cells, including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells, that were derived from all 3 germ layers; moreover, they demonstrated intestinal functions, including peptide absorption, and showed innervated bowel movements in response to stimulation with histamine and anticholinergic drugs. Importantly, the gut organoids obtained using this xenogeneic-free system could be stably maintained in culture for prolonged periods and were successfully engrafted in vivo. Our xenogeneic-free approach for generating gut organoids from hPSCs provides a platform for studying human intestinal diseases and for pharmacological testing.

  7. Recent advancements in plasmon-enhanced promising third-generation solar cells

    NASA Astrophysics Data System (ADS)

    Thrithamarassery Gangadharan, Deepak; Xu, Zhenhe; Liu, Yanlong; Izquierdo, Ricardo; Ma, Dongling

    2017-01-01

    The unique optical properties possessed by plasmonic noble metal nanostructures in consequence of localized surface plasmon resonance (LSPR) are useful in diverse applications like photovoltaics, sensing, non-linear optics, hydrogen generation, and photocatalytic pollutant degradation. The incorporation of plasmonic metal nanostructures into solar cells provides enhancement in light absorption and scattering cross-section (via LSPR), tunability of light absorption profile especially in the visible region of the solar spectrum, and more efficient charge carrier separation, hence maximizing the photovoltaic efficiency. This review discusses about the recent development of different plasmonic metal nanostructures, mainly based on Au or Ag, and their applications in promising third-generation solar cells such as dye-sensitized solar cells, quantum dot-based solar cells, and perovskite solar cells.

  8. TCR ITAM multiplicity is required for the generation of follicular helper T-cells.

    PubMed

    Hwang, SuJin; Palin, Amy C; Li, LiQi; Song, Ki-Duk; Lee, Jan; Herz, Jasmin; Tubo, Noah; Chu, Hamlet; Pepper, Marion; Lesourne, Renaud; Zvezdova, Ekaterina; Pinkhasov, Julia; Jenkins, Marc K; McGavern, Dorian; Love, Paul E

    2015-05-11

    The T-cell antigen receptor (TCR) complex contains 10 copies of a di-tyrosine Immunoreceptor-Tyrosine-based-Activation-Motif (ITAM) that initiates TCR signalling by recruiting protein tyrosine kinases. ITAM multiplicity amplifies TCR signals, but the importance of this capability for T-cell responses remains undefined. Most TCR ITAMs (6 of 10) are contributed by the CD3ζ subunits. We generated 'knock-in' mice that express non-signalling CD3ζ chains in lieu of wild-type CD3ζ. Here we demonstrate that ITAM multiplicity is important for the development of innate-like T-cells and follicular helper T-cells, events that are known to require strong/sustained TCR-ligand interactions, but is not essential for 'general' T-cell responses including proliferation and cytokine production or for the generation of a diverse antigen-reactive TCR repertoire.

  9. Recent advancements in plasmon-enhanced promising third-generation solar cells

    NASA Astrophysics Data System (ADS)

    Thrithamarassery Gangadharan, Deepak; Xu, Zhenhe; Liu, Yanlong; Izquierdo, Ricardo; Ma, Dongling

    2016-08-01

    The unique optical properties possessed by plasmonic noble metal nanostructures in consequence of localized surface plasmon resonance (LSPR) are useful in diverse applications like photovoltaics, sensing, non-linear optics, hydrogen generation, and photocatalytic pollutant degradation. The incorporation of plasmonic metal nanostructures into solar cells provides enhancement in light absorption and scattering cross-section (via LSPR), tunability of light absorption profile especially in the visible region of the solar spectrum, and more efficient charge carrier separation, hence maximizing the photovoltaic efficiency. This review discusses about the recent development of different plasmonic metal nanostructures, mainly based on Au or Ag, and their applications in promising third-generation solar cells such as dye-sensitized solar cells, quantum dot-based solar cells, and perovskite solar cells.

  10. High-throughput generation of spheroids using magnetic nanoparticles for three-dimensional cell culture.

    PubMed

    Kim, Jeong Ah; Choi, Jong-Ho; Kim, Minsoo; Rhee, Won Jong; Son, Boram; Jung, Hyun-Kyo; Park, Tai Hyun

    2013-11-01

    Various attempts have been made to develop three-dimensional (3-D) cell culture methods because 3-D cells mimic the structures and functional properties of real tissue compared with those of monolayer cultures. Here, we report on a highly simple and efficient 3-D spheroid generation method based on a magnetic pin-array system to concentrate magnetic nanoparticle-incorporated cells in a focal direction. This system was comprised only of external magnets and magnetically induced iron pins to generate a concentrated magnetic field for attracting cells in a focused direction. 3-D spheroid generation was achieved simply by adding magnetic nanoparticle-incorporated cells into a well and covering the plate with a magnetic lid. Cell clustering occurred rapidly within 5 min and created more compact cells with time through the focused magnetic force. This system ensured not only reproducible and size-controlled generation of spheroids but also versatile types of spheroids such as random mixed, core-shell, and fused spheroids, providing a very useful tool for various biological applications.

  11. Generation recruitment and death of brain cells throughout the life cycle of Sorex shrews (Lipotyphla).

    PubMed

    Bartkowska, Katarzyna; Djavadian, Rouzanna L; Taylor, Jan R E; Turlejski, Kris

    2008-04-01

    Young shrews of the genus Sorex that are born in early summer reduce their body size before wintering, including a reduction of brain weight of 10-30%. In the spring they mature sexually, double their body weight and regain about half of the loss in brain weight. To investigate the mechanisms of brain weight oscillations we studied the rate of cell death and generation in the brain during the whole life cycle of the common shrew (Sorex araneus) and pygmy shrew (S. minutus). After weaning, shrews generate new brain cells in only two mammalian neurogenic zones and approximately 80% of these develop into neurones. The increase of the shrew brain weight in the spring did not depend on recruitment of new cells. Moreover, adult Sorex shrews did not generate new cells in the dentate gyri. Injections of 5-HT1A receptor agonists in the adult shrews induced neurogenesis in their dentate gyri, showing the presence of dormant progenitor cells. Generation of new neurones in the subventricular zone of the lateral ventricles and their recruitment to olfactory bulbs continued throughout life. TUNEL labelling showed that the rate of cell death in all brain structures, including the proliferation zones and olfactory bulb, was very low throughout life. We conclude that neither cell death nor recruitment significantly contributes to seasonal oscillations and the net loss of brain weight in the Sorex shrews. With the exception of dentate gyrus and olfactory bulb, cellular populations of brain structures are stable throughout the life cycle of these shrews.

  12. In vitro T cell-mediated killing of Pseudomonas aeruginosa. V. Generation of bactericidal T cells in nonresponder mice.

    PubMed

    Powderly, W G; Pier, G B; Markham, R B

    1987-04-01

    We have previously reported that BALB/c mice immunized with 10 micrograms of a Pseudomonas aeruginosa polysaccharide antigen (PS) and 100 micrograms vinblastine sulfate develop T cell-mediated protective immunity, but fail to generate an antibody response. Vinblastine functions in this system to remove a suppressor cell that normally inhibits expression of this form of immunity after PS immunization. T cells from CB.20 mice immunized with the 10 micrograms of PS and 100 micrograms vinblastine fail to kill P. aeruginosa in vitro. These mice are allotype congenic with BALB/c mice, differing at loci closely linked to the IgH-1 locus. Immunization of CB.20 mice with 10 micrograms PS and 100 micrograms vinblastine results in the appearance of T cells which suppress in vitro bactericidal activity of BALB/c T cells. In the current study we found that T cell-mediated bactericidal activity can be generated in CB.20 mice by increasing the dose of vinblastine given at the time of PS immunization. The phenotype of the CB.20 bactericidal T cell generated by high dose vinblastine is identical to that of the BALB/c bactericidal T cell, and the CB.20 bactericidal T cell can adoptively transfer protective immunity to granulocytopenic mice. After immunization of BALB/c and CB.20 mice with PS alone, approximately one log fewer CB.20 T cells than BALB/c T cells are required to suppress bacterial killing in vitro. Furthermore, the number of CB.20 T cells required to suppress in vitro bacterial killing is directly correlated with the dose of vinblastine administered at the time of immunization. Increasing the immunizing dose of PS overcomes suppressor activity and allows the generation of bactericidal T cells in BALB/c mice without a requirement for vinblastine. CB.20 mice fail to generate bactericidal T cells after immunization with high doses of PS. These results indicate that CB.20 and BALB/c mice both possess the full repertoire of T cells required to express bactericidal T cell

  13. Generation and genetic modification of induced pluripotent stem cells.

    PubMed

    Schambach, Axel; Cantz, Tobias; Baum, Christopher; Cathomen, Toni

    2010-07-01

    The generation of induced pluripotent stem cells (iPSCs) enabled by exogenous expression of the canonical Oct4, Sox2, Klf4 and c-Myc reprogramming factors has opened new ways to create patient- or disease-specific pluripotent cells. iPSCs represent an almost inexhaustible source of cells for targeted differentiation into somatic effector cells and hence are likely to be invaluable for therapeutic applications and disease-related research. After an introduction on the biology of reprogramming we cover emerging technological advances, including new reprogramming approaches, small-molecule compounds and tailored genetic modification, and give an outlook towards potential clinical applications of iPSCs. Although this field is progressing rapidly, reprogramming is still an inefficient process. The reader will learn about innovative tools to generate patient-specific iPSCs and how to modify these established lines in a safe way. Ideally, the disease-causing mutation is edited directly in the genome using novel technologies based on artificial nucleases, such as zinc-finger nucleases. Human iPSCs create fascinating options with regard to disease modeling, drug testing, developmental studies and therapeutic applications. However, important hurdles have to be taken and more efficient protocols to be established to achieve the ambitious goal of bringing iPSCs into clinical use.

  14. International Space Station United States Oxygen Generator Development Testing

    NASA Technical Reports Server (NTRS)

    Erickson, Robert J.; Mason, Richard K.

    2000-01-01

    A life test of a liquid anode feed oxygen generator assembly (OGA) using SPE(R) (United Technologies Corporation, Hamilton Sundstrand Division) membrane technology was terminated in June of 1999. In the total 15,658 hours of operation at MSFC since delivery in 1995, the OGA has produced 2,103 kilograms (kg) (4,632 pounds mass (lbm)) of oxygen, and 263 kg (579 lbm) of hydrogen. Evaluation of cell stack characteristics and oxygen and hydrogen hydrophilic/hydrophobic membrane separators will be discussed.

  15. High Efficiency Quantum Dot Solar Cells Based on Multiple Exciton Generation

    SciTech Connect

    Breeze, Alison

    2011-04-15

    The objective of this project was to demonstrate that efficient multiple exciton generation observed in quantum dot materials could be harvested in nanostructured solar cells to dramatically improve the maximum power efficiency obtainable in photovoltaic modules. This proposal aimed to develop a high efficiency solar cell through a combination of quantum dot materials, nanostructured surfaces and atomic layer deposition for fabricating conformal and ultrathin films.

  16. Isolation and Analysis of Novel Electrochemically Active Bacteria for Enhanced Power Generation in Microbial Fuel Cells

    DTIC Science & Technology

    2009-03-07

    reducing strain ( Geobacter sulfurreducens ) produced less power than a mixed culture dominated by the same strain. Using a newly developed U-tube MFC, we...Pictures by D. Xing). CBET 0730359, Pi-Logan. Microbial fuel cell architecture Comparison of electrode reduction activities of Geobacter sulfurreducens ...and an enriched consortium in an air-cathode microbial fuel cell. An electricity generating bacterium, Geobacter sulfurreducens PCA, was inoculated

  17. Diaphragm Pressure Wave Generator Developments at Industrial Research Ltd

    NASA Astrophysics Data System (ADS)

    Caughley, A. J.; Emery, N.; Glasson, N. D.

    2010-04-01

    Industrial Research Ltd (IRL) have been developing a unique diaphragm based pressure wave generator technology for pulse tube and Stirling cryocoolers. Our system uses a metal diaphragm to separate the clean cryocooler gas circuit from a conventionally lubricated mechanical driver, thus producing a clean pressure wave with a long life drive that does not require the precision manufacture and associated costs of large linear motors. The first successful diaphragm pressure wave generator produced 3.2 kW of acoustic power at an electro-acoustic efficiency of 72% with a swept volume of 200 ml and a prototype has now accumulated over 2500 hours running. This paper describes recent developments in the technology. To explore scaling, a small diaphragm pressure wave generator with a swept volume of 20 ml has been constructed and has delivered 454 W of acoustic power at an electro-acoustic efficiency of 60%. Improvements have been made to the hydraulic force amplifier mechanism for driving the diaphragms resulting in a cheaper and lighter mechanism than the mechanical linkage originally used. To meet a customer's specific requirements, the 200 ml pressure wave generator's stroke was extended to achieve 240 ml of swept volume thereby increasing its acoustic power delivery to 4.1 kW without compromising efficiency.

  18. Asymmetric cell divisions: a view from plant development.

    PubMed

    Abrash, Emily B; Bergmann, Dominique C

    2009-06-01

    All complex multicellular organisms must solve the problem of generating diverse and appropriately patterned cell types. Asymmetric division, in which a single mother cell gives rise to daughters with distinct identities, is instrumental in the generation of cellular diversity and higher-level patterns. In animal systems, there exists considerable evidence for conserved mechanisms of polarization and asymmetric division. Here, we consider asymmetric cell divisions in plants, highlighting the unique aspects of plant cell biology and organismal development that constrain the process, but also emphasizing conceptual and mechanistic similarities with animal asymmetric divisions.

  19. Generation and properties of a new human ventral mesencephalic neural stem cell line

    SciTech Connect

    Villa, Ana; Liste, Isabel; Courtois, Elise T.; Seiz, Emma G.; Ramos, Milagros; Meyer, Morten; Juliusson, Bengt; Kusk, Philip

    2009-07-01

    Neural stem cells (NSCs) are powerful research tools for the design and discovery of new approaches to cell therapy in neurodegenerative diseases like Parkinson's disease. Several epigenetic and genetic strategies have been tested for long-term maintenance and expansion of these cells in vitro. Here we report the generation of a new stable cell line of human neural stem cells derived from ventral mesencephalon (hVM1) based on v-myc immortalization. The cells expressed neural stem cell and radial glia markers like nestin, vimentin and 3CB2 under proliferation conditions. After withdrawal of growth factors, proliferation and expression of v-myc were dramatically reduced and the cells differentiated into astrocytes, oligodendrocytes and neurons. hVM1 cells yield a large number of dopaminergic neurons (about 12% of total cells are TH{sup +}) after differentiation, which also produce dopamine. In addition to proneural genes (NGN2, MASH1), differentiated cells show expression of several genuine mesencephalic dopaminergic markers such as: LMX1A, LMX1B, GIRK2, ADH2, NURR1, PITX3, VMAT2 and DAT, indicating that they retain their regional identity. Our data indicate that this cell line and its clonal derivatives may constitute good candidates for the study of development and physiology of human dopaminergic neurons in vitro, and to develop tools for Parkinson's disease cell replacement preclinical research and drug testing.

  20. Meiosis and retrotransposon silencing during germ cell development in mice.

    PubMed

    Ollinger, Rupert; Reichmann, Judith; Adams, Ian R

    2010-03-01

    In mammals, germ cells derive from the pluripotent cells that are present early in embryogenesis, and then differentiate into male sperm or female eggs as development proceeds. Fusion between an egg and a sperm at fertilization allows genetic information from both parents to be transmitted to the next generation, and produces a pluripotent zygote to initiate the next round of embryogenesis. Meiosis is a central event in this self-perpetuating cycle that creates genetic diversity by generating new combinations of existing genetic alleles, and halves the number of chromosomes in the developing male and female germ cells to allow chromosome number to be maintained through successive generations. The developing germ cells also help to maintain genetic and chromosomal stability through the generations by protecting the genome from excessive de novo mutation. Several mouse mutants have recently been characterised whose germ cells exhibit defects in silencing the potentially mutagenic endogenous retroviruses and other retrotransposons that are prevalent in mammalian genomes, and these germ cells also exhibit defects in progression through meiosis. Here we review how mouse germ cells develop and proceed through meiosis, how mouse germ cells silence endogenous retroviruses and other retrotransposons, and discuss why silencing of endogenous retroviruses and other retrotransposons may be required for meiotic progression in mice.

  1. Generation of cell diversity and segmental pattern in the embryonic central nervous system of Drosophila.

    PubMed

    Technau, Gerhard M; Berger, Christian; Urbach, Rolf

    2006-04-01

    Development of the central nervous system (CNS) involves the transformation of a two-dimensional epithelial sheet of uniform ectodermal cells, the neuroectoderm, into a highly complex three-dimensional structure consisting of a huge variety of different neural cell types. Characteristic numbers of each cell type become arranged in reproducible spatial patterns, which is a prerequisite for the establishment of specific functional contacts. The fruitfly Drosophila is a suitable model to approach the mechanisms controlling the generation of cell diversity and pattern in the developing CNS, as it allows linking of gene function to individually identifiable cells. This review addresses aspects of the formation and specification of neural stem cells (neuroblasts) in Drosophila in the light of recent studies on their segmental diversification.

  2. Generating trunk neural crest from human pluripotent stem cells.

    PubMed

    Huang, Miller; Miller, Matthew L; McHenry, Lauren K; Zheng, Tina; Zhen, Qiqi; Ilkhanizadeh, Shirin; Conklin, Bruce R; Bronner, Marianne E; Weiss, William A

    2016-01-27

    Neural crest cells (NCC) are stem cells that generate different lineages, including neuroendocrine, melanocytic, cartilage, and bone. The differentiation potential of NCC varies according to the level from which cells emerge along the neural tube. For example, only anterior "cranial" NCC form craniofacial bone, whereas solely posterior "trunk" NCC contribute to sympathoadrenal cells. Importantly, the isolation of human fetal NCC carries ethical and scientific challenges, as NCC induction typically occur before pregnancy is detectable. As a result, current knowledge of NCC biology derives primarily from non-human organisms. Important differences between human and non-human NCC, such as expression of HNK1 in human but not mouse NCC, suggest a need to study human NCC directly. Here, we demonstrate that current protocols to differentiate human pluripotent stem cells (PSC) to NCC are biased toward cranial NCC. Addition of retinoic acid drove trunk-related markers and HOX genes characteristic of a posterior identity. Subsequent treatment with bone morphogenetic proteins (BMPs) enhanced differentiation to sympathoadrenal cells. Our approach provides methodology for detailed studies of human NCC, and clarifies roles for retinoids and BMPs in the differentiation of human PSC to trunk NCC and to sympathoadrenal lineages.

  3. Generating trunk neural crest from human pluripotent stem cells

    PubMed Central

    Huang, Miller; Miller, Matthew L.; McHenry, Lauren K.; Zheng, Tina; Zhen, Qiqi; Ilkhanizadeh, Shirin; Conklin, Bruce R.; Bronner, Marianne E.; Weiss, William A.

    2016-01-01

    Neural crest cells (NCC) are stem cells that generate different lineages, including neuroendocrine, melanocytic, cartilage, and bone. The differentiation potential of NCC varies according to the level from which cells emerge along the neural tube. For example, only anterior “cranial” NCC form craniofacial bone, whereas solely posterior “trunk” NCC contribute to sympathoadrenal cells. Importantly, the isolation of human fetal NCC carries ethical and scientific challenges, as NCC induction typically occur before pregnancy is detectable. As a result, current knowledge of NCC biology derives primarily from non-human organisms. Important differences between human and non-human NCC, such as expression of HNK1 in human but not mouse NCC, suggest a need to study human NCC directly. Here, we demonstrate that current protocols to differentiate human pluripotent stem cells (PSC) to NCC are biased toward cranial NCC. Addition of retinoic acid drove trunk-related markers and HOX genes characteristic of a posterior identity. Subsequent treatment with bone morphogenetic proteins (BMPs) enhanced differentiation to sympathoadrenal cells. Our approach provides methodology for detailed studies of human NCC, and clarifies roles for retinoids and BMPs in the differentiation of human PSC to trunk NCC and to sympathoadrenal lineages. PMID:26812940

  4. Development of a fourth generation predictive capability maturity model.

    SciTech Connect

    Hills, Richard Guy; Witkowski, Walter R.; Urbina, Angel; Rider, William J.; Trucano, Timothy Guy

    2013-09-01

    The Predictive Capability Maturity Model (PCMM) is an expert elicitation tool designed to characterize and communicate completeness of the approaches used for computational model definition, verification, validation, and uncertainty quantification associated for an intended application. The primary application of this tool at Sandia National Laboratories (SNL) has been for physics-based computational simulations in support of nuclear weapons applications. The two main goals of a PCMM evaluation are 1) the communication of computational simulation capability, accurately and transparently, and 2) the development of input for effective planning. As a result of the increasing importance of computational simulation to SNLs mission, the PCMM has evolved through multiple generations with the goal to provide more clarity, rigor, and completeness in its application. This report describes the approach used to develop the fourth generation of the PCMM.

  5. Development and evaluation of a hybrid averaged orbit generator

    NASA Technical Reports Server (NTRS)

    Mcclain, W. D.; Long, A. C.; Early, L. W.

    1978-01-01

    A rapid orbit generator based on a first-order application of the Generalized Method of Averaging has been developed for the Research and Development (R&D) version of the Goddard Trajectory Determination System (GTDS). The evaluation of the averaged equations of motion can use both numerically averaged and recursively evaluated, analytically averaged perturbation models. These equations are numerically integrated to obtain the secular and long-period motion. Factors affecting efficient orbit prediction are discussed and guidelines are presented for treatment of each major perturbation. Guidelines for obtaining initial mean elements compatible with the theory are presented. An overview of the orbit generator is presented and comparisons with high precision methods are given.

  6. Development of Composite Technologies for the European Next Generation Launcher

    NASA Astrophysics Data System (ADS)

    Fatemi, Javad; van der Bas, Finn

    2014-06-01

    In the frame of the European Space Agency's Future Launchers Preparatory Programme (FLPP), in conjunction with national Research and Technology programs, Dutch Space has undertaken the development of composite technologies for application in the Europe's next generation launcher, Ariane 6. The efforts have focused on development of a Carbon Fibre Reinforced Plastic (CFRP) Engine Thrust Frame (ETF) for the upper-stage of Ariane6 launcher. These new technologies are expected to improve performance and to lower cost of development and exploitation of the launcher. Although the first targeted application is the thrust frame, the developed technologies are set to be generic in the sense that they can be applied to other structures of the launcher, e.g. inter-stage structures.This paper addresses the design, analysis, manufacturing and testing activities related to the composite technology developments.

  7. Fuel cell development for transportation: Catalyst development

    SciTech Connect

    Doddapaneni, N.

    1996-04-01

    Fuel cells are being considered as alternate power sources for transportation and stationary applications. With proton exchange membrane (PEM) fuel cells the fuel crossover to cathodes causes severe thermal management and cell voltage drop due to oxidation of fuel at the platinized cathodes. The main goal of this project was to design, synthesize, and evaluate stable and inexpensive transition metal macrocyclic catalysts for the reduction of oxygen and be electrochemically inert towards anode fuels such as hydrogen and methanol.

  8. NNSA Program Develops the Next Generation of Nuclear Security Experts

    SciTech Connect

    Brim, Cornelia P.; Disney, Maren V.

    2015-09-02

    NNSA is fostering the next generation of nuclear security experts is through its successful NNSA Graduate Fellowship Program (NGFP). NGFP offers its Fellows an exceptional career development opportunity through hands-on experience supporting NNSA mission areas across policy and technology disciplines. The one-year assignments give tomorrow’s leaders in global nuclear security and nonproliferation unparalleled exposure through assignments to Program Offices across NNSA.

  9. Radioisotope thermoelectric generator transportation system subsystem 143 software development plan

    SciTech Connect

    King, D.A.

    1994-11-10

    This plan describes the activities to be performed and the controls to be applied to the process of specifying, developing, and qualifying the data acquisition software for the Radioisotope Thermoelectric Generator (RTG) Transportation System Subsystem 143 Instrumentation and Data Acquisition System (IDAS). This plan will serve as a software quality assurance plan, a verification and validation (V and V) plan, and a configuration management plan.

  10. Radioisotope thermoelectric generator transportation system subsystem 143 software development plan

    NASA Astrophysics Data System (ADS)

    King, D. A.

    1994-11-01

    This plan describes the activities to be performed and the controls to be applied to the process of specifying, developing, and qualifying the data acquisition software for the Radioisotope Thermoelectric Generator (RTG) Transportation System Subsystem 143 Instrumentation and Data Acquisition System (IDAS). This plan will serve as a software quality assurance plan, a verification and validation (V and V) plan, and a configuration management plan.

  11. The next generation high data rate VCSEL development at SEDU

    NASA Astrophysics Data System (ADS)

    Xie, Chuan; Li, Neinyi; Huang, Shenghong; Liu, Chiyu; Wang, Li; Jackson, Kenneth P.

    2013-03-01

    In May of 2012, Emcore's VCSEL FAB and VCSEL based transceiver business joined Sumitomo Electric Device Innovations USA (SEDU). After this change of ownership, our high speed VCSEL development effort continues. In this paper, we will report the progress we made in the past year in our 25Gbps to 28Gbps VCSEL. This next generation device is targeted for EDR, 32GFC as well as other optical interconnect applications.

  12. Early stage hot spot analysis through standard cell base random pattern generation

    NASA Astrophysics Data System (ADS)

    Jeon, Joong-Won; Song, Jaewan; Kim, Jeong-Lim; Park, Seongyul; Yang, Seung-Hune; Lee, Sooryong; Kang, Hokyu; Madkour, Kareem; ElManhawy, Wael; Lee, SeungJo; Kwan, Joe

    2017-04-01

    Due to limited availability of DRC clean patterns during the process and RET recipe development, OPC recipes are not tested with high pattern coverage. Various kinds of pattern can help OPC engineer to detect sensitive patterns to lithographic effects. Random pattern generation is needed to secure robust OPC recipe. However, simple random patterns without considering real product layout style can't cover patterning hotspot in production levels. It is not effective to use them for OPC optimization thus it is important to generate random patterns similar to real product patterns. This paper presents a strategy for generating random patterns based on design architecture information and preventing hotspot in early process development stage through a tool called Layout Schema Generator (LSG). Using LSG, we generate standard cell based on random patterns reflecting real design cell structure - fin pitch, gate pitch and cell height. The output standard cells from LSG are applied to an analysis methodology to assess their hotspot severity by assigning a score according to their optical image parameters - NILS, MEEF, %PV band and thus potential hotspots can be defined by determining their ranking. This flow is demonstrated on Samsung 7nm technology optimizing OPC recipe and early enough in the process avoiding using problematic patterns.

  13. T-cell libraries allow simple parallel generation of multiple peptide-specific human T-cell clones.

    PubMed

    Theaker, Sarah M; Rius, Cristina; Greenshields-Watson, Alexander; Lloyd, Angharad; Trimby, Andrew; Fuller, Anna; Miles, John J; Cole, David K; Peakman, Mark; Sewell, Andrew K; Dolton, Garry

    2016-03-01

    Isolation of peptide-specific T-cell clones is highly desirable for determining the role of T-cells in human disease, as well as for the development of therapies and diagnostics. However, generation of monoclonal T-cells with the required specificity is challenging and time-consuming. Here we describe a library-based strategy for the simple parallel detection and isolation of multiple peptide-specific human T-cell clones from CD8(+) or CD4(+) polyclonal T-cell populations. T-cells were first amplified by CD3/CD28 microbeads in a 96U-well library format, prior to screening for desired peptide recognition. T-cells from peptide-reactive wells were then subjected to cytokine-mediated enrichment followed by single-cell cloning, with the entire process from sample to validated clone taking as little as 6 weeks. Overall, T-cell libraries represent an efficient and relatively rapid tool for the generation of peptide-specific T-cell clones, with applications shown here in infectious disease (Epstein-Barr virus, influenza A, and Ebola virus), autoimmunity (type 1 diabetes) and cancer.

  14. Optimal culture conditions for the generation of natural killer cell-induced dendritic cells for cancer immunotherapy.

    PubMed

    Nguyen-Pham, Thanh-Nhan; Yang, Deok-Hwan; Nguyen, Truc-Anh Thi; Lim, Mi-Seon; Hong, Cheol Yi; Kim, Mi-Hyun; Lee, Hyun Ju; Lee, Youn-Kyung; Cho, Duck; Bae, Soo-Young; Ahn, Jae-Sook; Kim, Yeo-Kyeoung; Chung, Ik-Joo; Kim, Hyeoung-Joon; Lee, Je-Jung

    2012-01-01

    Dendritic cell (DC)-based vaccines continue to be considered an attractive tool for cancer immunotherapy. DCs require an additional signal from the environment or other immune cells to polarize the development of immune responses toward T helper 1 (Th1) or Th2 responses. DCs play a role in natural killer (NK) cell activation, and NK cells are also able to activate and induce the maturation of DCs. We investigated the types of NK cells that can induce the maturation and enhanced function of DCs and the conditions under which these interactions occur. DCs that were activated by resting NK cells in the presence of inflammatory cytokines exhibited increased expression of several costimulatory molecules and an enhanced ability to produce IL-12p70. NK cell-stimulated DCs potently induced Th1 polarization and exhibited the ability to generate tumor antigen-specific cytotoxic T lymphocyte responses. Our data demonstrate that functional DCs can be generated by coculturing immature DCs with freshly isolated resting NK cells in the presence of Toll-like receptor agonists and proinflammatory cytokines and that the resulting DCs effectively present antigens to induce tumor-specific T-cell responses, which suggests that these cells may be useful for cancer immunotherapy.

  15. T-cell libraries allow simple parallel generation of multiple peptide-specific human T-cell clones

    PubMed Central

    Theaker, Sarah M.; Rius, Cristina; Greenshields-Watson, Alexander; Lloyd, Angharad; Trimby, Andrew; Fuller, Anna; Miles, John J.; Cole, David K.; Peakman, Mark; Sewell, Andrew K.; Dolton, Garry

    2016-01-01

    Isolation of peptide-specific T-cell clones is highly desirable for determining the role of T-cells in human disease, as well as for the development of therapies and diagnostics. However, generation of monoclonal T-cells with the required specificity is challenging and time-consuming. Here we describe a library-based strategy for the simple parallel detection and isolation of multiple peptide-specific human T-cell clones from CD8+ or CD4+ polyclonal T-cell populations. T-cells were first amplified by CD3/CD28 microbeads in a 96U-well library format, prior to screening for desired peptide recognition. T-cells from peptide-reactive wells were then subjected to cytokine-mediated enrichment followed by single-cell cloning, with the entire process from sample to validated clone taking as little as 6 weeks. Overall, T-cell libraries represent an efficient and relatively rapid tool for the generation of peptide-specific T-cell clones, with applications shown here in infectious disease (Epstein–Barr virus, influenza A, and Ebola virus), autoimmunity (type 1 diabetes) and cancer. PMID:26826277

  16. Serum- and stromal cell-free hypoxic generation of embryonic stem cell-derived hematopoietic cells in vitro, capable of multilineage repopulation of immunocompetent mice.

    PubMed

    Lesinski, Dietrich Armin; Heinz, Niels; Pilat-Carotta, Sandra; Rudolph, Cornelia; Jacobs, Roland; Schlegelberger, Brigitte; Klump, Hannes; Schiedlmeier, Bernhard

    2012-08-01

    Induced pluripotent stem cells (iPSCs) may become a promising source for the generation of patient-specific hematopoietic stem cells (HSCs) in vitro. A crucial prerequisite will be the availability of reliable protocols for the directed and efficient differentiation toward HSCs. So far, the most robust strategy for generating HSCs from pluripotent cells in vitro has been established in the mouse model involving ectopic expression of the human transcription factor HOXB4. However, most differentiation protocols include coculture on a xenogenic stroma cell line and the use of animal serum. Involvement of any of both would pose a major barrier to the translation of those protocols to human autologous iPSCs intended for clinical use. Therefore, we asked whether long-term repopulating HSCs can, in principle, be generated from embryonic stem cells without stroma cells or serum. Here, we showed that long-term multilineage engraftment could be accomplished in immunocompetent mice when HSCs were generated in serum-free medium without stroma cell support and when hypoxic conditions were used. Under those conditions, HOXB4(+) embryonic stem cell-derived hematopoietic stem and progenitor cells were immunophenotypically similar to definitive bone marrow resident E-SLAM(+) (CD150(+)CD48(-)CD45(+)CD201(+)) HSCs. Thus, our findings may ease the development of definitive, adult-type HSCs from pluripotent stem cells, entirely in vitro.

  17. Development and bottlenecks of renewable electricity generation in China: a critical review.

    PubMed

    Hu, Yuanan; Cheng, Hefa

    2013-04-02

    This review provides an overview on the development and status of electricity generation from renewable energy sources, namely hydropower, wind power, solar power, biomass energy, and geothermal energy, and discusses the technology, policy, and finance bottlenecks limiting growth of the renewable energy industry in China. Renewable energy, dominated by hydropower, currently accounts for more than 25% of the total electricity generation capacity. China is the world's largest generator of both hydropower and wind power, and also the largest manufacturer and exporter of photovoltaic cells. Electricity production from solar and biomass energy is at the early stages of development in China, while geothermal power generation has received little attention recently. The spatial mismatch in renewable energy supply and electricity demand requires construction of long-distance transmission networks, while the intermittence of renewable energy poses significant technical problems for feeding the generated electricity into the power grid. Besides greater investment in research and technology development, effective policies and financial measures should also be developed and improved to better support the healthy and sustained growth of renewable electricity generation. Meanwhile, attention should be paid to the potential impacts on the local environment from renewable energy development, despite the wider benefits for climate change.

  18. Bacillus subtilis Swarmer Cells Lead the Swarm, Multiply, and Generate a Trail of Quiescent Descendants

    PubMed Central

    Hamouche, Lina; Laalami, Soumaya; Daerr, Adrian; Song, Solène; Holland, I. Barry; Séror, Simone J.; Hamze, Kassem

    2017-01-01

    ABSTRACT Bacteria adopt social behavior to expand into new territory, led by specialized swarmers, before forming a biofilm. Such mass migration of Bacillus subtilis on a synthetic medium produces hyperbranching dendrites that transiently (equivalent to 4 to 5 generations of growth) maintain a cellular monolayer over long distances, greatly facilitating single-cell gene expression analysis. Paradoxically, while cells in the dendrites (nonswarmers) might be expected to grow exponentially, the rate of swarm expansion is constant, suggesting that some cells are not multiplying. Little attention has been paid to which cells in a swarm are actually multiplying and contributing to the overall biomass. Here, we show in situ that DNA replication, protein translation and peptidoglycan synthesis are primarily restricted to the swarmer cells at dendrite tips. Thus, these specialized cells not only lead the population forward but are apparently the source of all cells in the stems of early dendrites. We developed a simple mathematical model that supports this conclusion. PMID:28174308

  19. Dynamic behaviour of human neuroepithelial cells in the developing forebrain

    PubMed Central

    Subramanian, Lakshmi; Bershteyn, Marina; Paredes, Mercedes F.; Kriegstein, Arnold R.

    2017-01-01

    To understand how diverse progenitor cells contribute to human neocortex development, we examined forebrain progenitor behaviour using timelapse imaging. Here we find that cell cycle dynamics of human neuroepithelial (NE) cells differ from radial glial (RG) cells in both primary tissue and in stem cell-derived organoids. NE cells undergoing proliferative, symmetric divisions retract their basal processes, and both daughter cells regrow a new process following cytokinesis. The mitotic retraction of the basal process is recapitulated by NE cells in cerebral organoids generated from human-induced pluripotent stem cells. In contrast, RG cells undergoing vertical cleavage retain their basal fibres throughout mitosis, both in primary tissue and in older organoids. Our findings highlight developmentally regulated changes in mitotic behaviour that may relate to the role of RG cells to provide a stable scaffold for neuronal migration, and suggest that the transition in mitotic dynamics can be studied in organoid models. PMID:28139695

  20. Cell fate control in the developing central nervous system

    SciTech Connect

    Guérout, Nicolas; Li, Xiaofei; Barnabé-Heider, Fanie

    2014-02-01

    The principal neural cell types forming the mature central nervous system (CNS) are now understood to be diverse. This cellular subtype diversity originates to a large extent from the specification of the earlier proliferating progenitor populations during development. Here, we review the processes governing the differentiation of a common neuroepithelial cell progenitor pool into mature neurons, astrocytes, oligodendrocytes, ependymal cells and adult stem cells. We focus on studies performed in mice and involving two distinct CNS structures: the spinal cord and the cerebral cortex. Understanding the origin, specification and developmental regulators of neural cells will ultimately impact comprehension and treatments of neurological disorders and diseases. - Highlights: • Similar mechanisms regulate cell fate in different CNS cell types and structures. • Cell fate regulators operate in a spatial–temporal manner. • Different neural cell types rely on the generation of a diversity of progenitor cells. • Cell fate decision is dictated by the integration of intrinsic and extrinsic signals.

  1. Induced Pluripotent Stem Cells Generated from P0-Cre;Z/EG Transgenic Mice.

    PubMed

    Ogawa, Yasuhiro; Eto, Akira; Miyake, Chisato; Tsuchida, Nana; Miyake, Haruka; Takaku, Yasuhiro; Hagiwara, Hiroaki; Oishi, Kazuhiko

    2015-01-01

    Neural crest (NC) cells are a migratory, multipotent cell population that arises at the neural plate border, and migrate from the dorsal neural tube to their target tissues, where they differentiate into various cell types. Abnormal development of NC cells can result in severe congenital birth defects. Because only a limited number of cells can be obtained from an embryo, mechanistic studies are difficult to perform with directly isolated NC cells. Protein zero (P0) is expressed by migrating NC cells during the early embryonic period. In the P0-Cre;Z/EG transgenic mouse, transient activation of the P0 promoter induces Cre-mediated recombination, indelibly tagging NC-derived cells with enhanced green fluorescent protein (EGFP). Induced pluripotent stem cell (iPSC) technology offers new opportunities for both mechanistic studies and development of stem cell-based therapies. Here, we report the generation of iPSCs from the P0-Cre;Z/EG mouse. P0-Cre;Z/EG mouse-derived iPSCs (P/G-iPSCs) exhibited pluripotent stem cell properties. In lineage-directed differentiation studies, P/G-iPSCs were efficiently differentiated along the neural lineage while expressing EGFP. These results suggest that P/G-iPSCs are useful to study NC development and NC-associated diseases.

  2. Generation of functional, antigen-specific CD8+ human T cells from cord blood stem cells using exogenous Notch and tetramer-TCR signaling.

    PubMed

    Fernandez, Irina; Ooi, Tracy P; Roy, Krishnendu

    2014-01-01

    In vitro differentiation of mouse and human stem cells into early T cells has been successfully demonstrated using artificial Notch signaling systems. However, generation of mature, antigen-specific, functional T cells, directly from human stem cells has remained elusive, except when using stromal coculture of stem cells retrovirally transfected with antigen-specific T cell receptors (TCRs). Here we show that human umbilical cord blood (UCB)-derived CD34+CD38-/low hematopoietic stem cells can be successfully differentiated into functional, antigen-specific cytotoxic CD8+ T cells without direct stromal coculture or retroviral TCR transfection. Surface-immobilized Notch ligands (DLL1) and stromal cell conditioned medium successfully induced the development of CD1a+CD7+ and CD4+CD8+ early T cells. These cells, upon continued culture with cytomegalovirus (CMV) or influenza-A virus M1 (GIL) epitope-loaded human leukocyte antigen (HLA)-A*0201 tetramers, resulted in the generation of a polyclonal population of CMV-specific or GIL-specific CD8+ T cells, respectively. Upon further activation with antigen-loaded target cells, these antigen-specific, stem cell-derived T cells exhibited cytolytic functionality, specifically CD107a surface mobilization, interferon gamma (IFNg) production, and Granzyme B secretion. Such scalable, in vitro generation of functional, antigen-specific T cells from human stem cells could eventually provide a readily available cell source for adoptive transfer immunotherapies and also allow better understanding of human T cell development.

  3. Development of Next Generation Segmented Thermoelectric Radioisotope Power Systems

    NASA Astrophysics Data System (ADS)

    Fleurial, J.; Caillat, T.; Ewell, R. C.

    2005-12-01

    Radioisotope thermoelectric generators have been used for space-based applications since 1961 with a total of 22 space missions that have successfully used RTGs for electrical power production. The key advantages of radioisotope thermoelectric generators (RTGs) are their long life, robustness, compact size, and high reliability. Thermoelectric converters are easily scalable, and possess a linear current-voltage curve, making power generation easy to control via a shunt regulator and shunt radiator. They produce no noise, vibration or torque during operation. These properties have made RTGs ideally suitable for autonomous missions in the extreme environments of outer space and on planetary surfaces. More advanced radioisotope power systems (RPS) with higher specific power (W/kg) and/or power output are desirable for future NASA missions, including the Europa Geophysical Orbiter mission. For the past few years, the Jet Propulsion Laboratory (JPL) has been developing more efficient thermoelectric materials and has demonstrated significant increases in the conversion efficiency of high temperature thermocouples, up to 14% when operated across a 975K to 300K temperature differential. In collaboration with NASA Glenn Research Center, universities (USC and UNM), Ceramic and Metal Composites Corporation and industrial partners, JPL is now planning to lead the research and development of advanced thermoelectric technology for integration into the next generations of RPS. Preliminary studies indicate that this technology has the potential for improving the RPS specific power by more than 50% over the current state-of-the-art multi-mission RTG being built for the Mars Science Laboratory mission. A second generation advanced RPS is projected at more than doubling the specific power.

  4. Multiple exciton generation in nanocrystalline solar cells (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Boehm, Marcus; Davis, Nathaniel; Greenham, Neil C.

    2016-09-01

    Multiple exciton generation (MEG) - a process in which multiple charge-carrier pairs are generated from a single optical excitation - is a promising way to improve the photocurrent in photovoltaic devices and offers the potential of breaking the Shockley-Queisser limit. It remains, however, challenging to harvest charge-carrier pairs generated by MEG in working solar cells. Initial yields of additional carrier pairs may be reduced due to ultra-fast intraband relaxation processes, which compete with MEG at early times. Quantum dots of materials, which display reduced carrier cooling rates (e.g. PbTe)[1] or one-dimensional nanostructures (e.g. nano rods)[2] which accelerate the carrier multiplication process are therefore promising candidates to increase the impact of MEG in photovoltaic devices. Here we show that both theorised strategies can lead to solar cells, which produce extractable charge carrier pairs with an external quantum efficiency above 120%, and we estimate an internal quantum efficiency exceeding 150%. Resolving the charge carrier kinetics on the ultra-fast timescale with pump-probe transient absorption and pump-push-photocurrent measurements, we identify a delayed cooling effect above the experimentally- determined threshold energy for MEG[1].

  5. Functional development of mechanosensitive hair cells in stem cell-derived organoids parallels native vestibular hair cells

    PubMed Central

    Liu, Xiao-Ping; Koehler, Karl R.; Mikosz, Andrew M.; Hashino, Eri; Holt, Jeffrey R.

    2016-01-01

    Inner ear sensory epithelia contain mechanosensitive hair cells that transmit information to the brain through innervation with bipolar neurons. Mammalian hair cells do not regenerate and are limited in number. Here we investigate the potential to generate mechanosensitive hair cells from mouse embryonic stem cells in a three-dimensional (3D) culture system. The system faithfully recapitulates mouse inner ear induction followed by self-guided development into organoids that morphologically resemble inner ear vestibular organs. We find that organoid hair cells acquire mechanosensitivity equivalent to functionally mature hair cells in postnatal mice. The organoid hair cells also progress through a similar dynamic developmental pattern of ion channel expression, reminiscent of two subtypes of native vestibular hair cells. We conclude that our 3D culture system can generate large numbers of fully functional sensory cells which could be used to investigate mechanisms of inner ear development and disease as well as regenerative mechanisms for inner ear repair. PMID:27215798

  6. Functional Human Podocytes Generated in Organoids from Amniotic Fluid Stem Cells.

    PubMed

    Xinaris, Christodoulos; Benedetti, Valentina; Novelli, Rubina; Abbate, Mauro; Rizzo, Paola; Conti, Sara; Tomasoni, Susanna; Corna, Daniela; Pozzobon, Michela; Cavallotti, Daniela; Yokoo, Takashi; Morigi, Marina; Benigni, Ariela; Remuzzi, Giuseppe

    2016-05-01

    Generating kidney organoids using human stem cells could offer promising prospects for research and therapeutic purposes. However, no cell-based strategy has generated nephrons displaying an intact three-dimensional epithelial filtering barrier. Here, we generated organoids using murine embryonic kidney cells, and documented that these tissues recapitulated the complex three-dimensional filtering structure of glomerular slits in vivo and accomplished selective glomerular filtration and tubular reabsorption. Exploiting this technology, we mixed human amniotic fluid stem cells with mouse embryonic kidney cells to establish three-dimensional chimeric organoids that engrafted in vivo and grew to form vascularized glomeruli and tubular structures. Human cells contributed to the formation of glomerular structures, differentiated into podocytes with slit diaphragms, and internalized exogenously infused BSA, thus attaining in vivo degrees of specialization and function unprecedented for donor stem cells. In conclusion, human amniotic fluid stem cell chimeric organoids may offer new paths for studying renal development and human podocyte disease, and for facilitating drug discovery and translational research.

  7. A xenogeneic-free system generating functional human gut organoids from pluripotent stem cells

    PubMed Central

    Uchida, Hajime; Machida, Masakazu; Miura, Takumi; Kawasaki, Tomoyuki; Sasaki, Kengo; Sakamoto, Seisuke; Ohuchi, Noriaki; Kasahara, Mureo; Umezawa, Akihiro

    2017-01-01

    Functional intestines are composed of cell types from all 3 primary germ layers and are generated through a highly orchestrated and serial developmental process. Directed differentiation of human pluripotent stem cells (hPSCs) has been shown to yield gut-specific cell types; however, these structures do not reproduce critical functional interactions between cell types of different germ layers. Here, we developed a simple protocol for the generation of mature functional intestinal organoids from hPSCs under xenogeneic-free conditions. The stem cell–derived gut organoids produced here were found to contain distinct types of intestinal cells, including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells, that were derived from all 3 germ layers; moreover, they demonstrated intestinal functions, including peptide absorption, and showed innervated bowel movements in response to stimulation with histamine and anticholinergic drugs. Importantly, the gut organoids obtained using this xenogeneic-free system could be stably maintained in culture for prolonged periods and were successfully engrafted in vivo. Our xenogeneic-free approach for generating gut organoids from hPSCs provides a platform for studying human intestinal diseases and for pharmacological testing. PMID:28097227

  8. Functional Human Podocytes Generated in Organoids from Amniotic Fluid Stem Cells

    PubMed Central

    Benedetti, Valentina; Novelli, Rubina; Abbate, Mauro; Rizzo, Paola; Conti, Sara; Tomasoni, Susanna; Corna, Daniela; Pozzobon, Michela; Cavallotti, Daniela; Yokoo, Takashi; Morigi, Marina; Benigni, Ariela; Remuzzi, Giuseppe

    2016-01-01

    Generating kidney organoids using human stem cells could offer promising prospects for research and therapeutic purposes. However, no cell-based strategy has generated nephrons displaying an intact three-dimensional epithelial filtering barrier. Here, we generated organoids using murine embryonic kidney cells, and documented that these tissues recapitulated the complex three-dimensional filtering structure of glomerular slits in vivo and accomplished selective glomerular filtration and tubular reabsorption. Exploiting this technology, we mixed human amniotic fluid stem cells with mouse embryonic kidney cells to establish three-dimensional chimeric organoids that engrafted in vivo and grew to form vascularized glomeruli and tubular structures. Human cells contributed to the formation of glomerular structures, differentiated into podocytes with slit diaphragms, and internalized exogenously infused BSA, thus attaining in vivo degrees of specialization and function unprecedented for donor stem cells. In conclusion, human amniotic fluid stem cell chimeric organoids may offer new paths for studying renal development and human podocyte disease, and for facilitating drug discovery and translational research. PMID:26516208

  9. Targeted organ generation using Mixl1-inducible mouse pluripotent stem cells in blastocyst complementation.

    PubMed

    Kobayashi, Toshihiro; Kato-Itoh, Megumi; Nakauchi, Hiromitsu

    2015-01-15

    Generation of functional organs from patients' own cells is one of the ultimate goals of regenerative medicine. As a novel approach to creation of organs from pluripotent stem cells (PSCs), we employed blastocyst complementation in organogenesis-disabled animals and successfully generated PSC-derived pancreas and kidneys. Blastocyst complementation, which exploits the capacity of PSCs to participate in forming chimeras, does not, however, exclude contribution of PSCs to the development of tissues-including neural cells or germ cells-other than those specifically targeted by disabling of organogenesis. This fact provokes ethical controversy if human PSCs are to be used. In this study, we demonstrated that forced expression of Mix-like protein 1 (encoded by Mixl1) can be used to guide contribution of mouse embryonic stem cells to endodermal organs after blastocyst injection. We then succeeded in applying this method to generate functional pancreas in pancreatogenesis-disabled Pdx1 knockout mice using a newly developed tetraploid-based organ-complementation method. These findings hold promise for targeted organ generation from patients' own PSCs in livestock animals.

  10. Electricity generation from synthetic acid-mine drainage (AMD) water using fuel cell technologies

    SciTech Connect

    Shaoan Cheng; Brian A. Dempsey; Bruce E. Logan

    2007-12-15

    Acid-mine drainage (AMD) is difficult and costly to treat. We investigated a new approach to AMD treatment using fuel cell technologies to generate electricity while removing iron from the water. Utilizing a recently developed microbial fuel cell architecture, we developed an acid-mine drainage fuel cell (AMD-FC) capable of abiotic electricity generation. The AMD-FC operated in fed-batch mode generated a maximum power density of 290 mW/m{sup 2} at a Coulombic efficiency greater than 97%. Ferrous iron was completely removed through oxidation to insoluble Fe(III), forming a precipitate in the bottom of the anode chamber and on the anode electrode. Several factors were examined to determine their effect on operation, including pH, ferrous iron concentration, and solution chemistry. Optimum conditions were a pH of 6.3 and a ferrous iron concentration above about 0.0036 M. These results suggest that fuel cell technologies can be used not only for treating AMD through removal of metals from solution, but also for producing useful products such as electricity and recoverable metals. Advances being made in wastewater fuel cells will enable more efficient power generation and systems suitable for scale-up. 35 refs., 8 figs.

  11. Electricity generation from cysteine in a microbial fuel cell.

    PubMed

    Logan, Bruce E; Murano, Cassandro; Scott, Keith; Gray, Neil D; Head, Ian M

    2005-03-01

    In a microbial fuel cell (MFC), power can be generated from the oxidation of organic matter by bacteria at the anode, with reduction of oxygen at the cathode. Proton exchange membranes used in MFCs are permeable to oxygen, resulting in the diffusion of oxygen into the anode chamber. This could either lower power generation by obligate anaerobes or result in the loss in electron donor from aerobic respiration by facultative or other aerobic bacteria. In order to maintain anaerobic conditions in conventional anaerobic laboratory cultures, chemical oxygen scavengers such as cysteine are commonly used. It is shown here that cysteine can serve as a substrate for electricity generation by bacteria in a MFC. A two-chamber MFC containing a proton exchange membrane was inoculated with an anaerobic marine sediment. Over a period of a few weeks, electricity generation gradually increased to a maximum power density of 19 mW/m(2) (700 or 1000 Omega resistor; 385 mg/L of cysteine). Power output increased to 39 mW/m(2) when cysteine concentrations were increased up to 770 mg/L (493 Omega resistor). The use of a more active cathode with Pt- or Pt-Ru, increased the maximum power from 19 to 33 mW/m(2) demonstrating that cathode efficiency limited power generation. Power was always immediately generated upon addition of fresh medium, but initial power levels consistently increased by ca. 30% during the first 24 h. Electron recovery as electricity was 14% based on complete cysteine oxidation, with an additional 14% (28% total) potentially lost to oxygen diffusion through the proton exchange membrane. 16S rRNA-based analysis of the biofilm on the anode of the MFC indicated that the predominant organisms were Shewanella spp. closely related to Shewanella affinis (37% of 16S rRNA gene sequences recovered in clone libraries).

  12. Cellular Silica Encapsulation for Development of Robust Cell Based Biosensors

    NASA Astrophysics Data System (ADS)

    Johnston, Robert; Rogelj, Snezna; Harper, Jason; Tartis, Michaelann

    2014-03-01

    In order to detect chemical and biological threats both on the battlefield and in civilian life, development of portable, robust detection systems capable of real-time identification of the chemical and biological agents are needed. Living cell-based sensors have proven effective as sensitive, specific, near real-time detectors; however, living cell-based sensors require frequent cell replenishment due to cell sensitivity to the ex-vivo environment, which limits sensor stability. Incorporation of living cells within a biocompatible matrix that provides mechanical protection and maintains access to the external environment may facilitate the development of long-term stable cell-based biosensors. We are exploring the use of a novel Chemical Vapor into Liquid (CViL) deposition process for whole cell encapsulation in silica. In CViL, the high vapor pressure of common silica alkoxides is utilized to deliver silica into an aqueous medium, creating a silica sol. Mixing of cells with the resulting silica sol facilitates encapsulation of cells in silica while minimizing cell contact with the cytotoxic products of silica generating reactions. Using fluorescence microscopy analysis with multiple silica specific markers, encapsulation of multiple eukaryotic cell types (Saccharomyces cerevisiae, Jurkat, HeLa, and U87 cells) with CViL generated silica is shown, providing a foundation for development of long -term stable cell-based biosensors with diverse sensing capabilities.

  13. Generation of Transgenic Mouse Fluorescent Reporter Lines for Studying Hematopoietic Development

    PubMed Central

    Vacaru, Andrei M.; Vitale, Joseph; Nieves, Johnathan; Baron, Margaret H.

    2015-01-01

    During the development of the hematopoietic system, at least 8 distinct lineages are generated in the mouse embryo. Transgenic mice expressing fluorescent proteins at various points in the hematopoietic hierarchy, from hematopoietic stem cell to multipotent progenitors to each of the final differentiated cell types, have provided valuable tools for tagging, tracking, and isolating these cells. In this chapter, we discuss general considerations in designing a transgene, survey available fluorescent probes, and methods for confirming and analyzing transgene expression in the hematopoietic systems of the embryo, fetus, and postnatal/adult animal. PMID:25064110

  14. Measuring cell-generated forces: a guide to the available tools.

    PubMed

    Polacheck, William J; Chen, Christopher S

    2016-04-28

    Forces generated by cells are critical regulators of cell adhesion, signaling, and function, and they are also essential drivers in the morphogenetic events of development. Over the past 20 years, several methods have been developed to measure these forces. However, despite recent substantial interest in understanding the contribution of these forces in biology, implementation and adoption of the developed methods by the broader biological community remain challenging because of the inherently multidisciplinary expertise required to conduct and interpret the measurements. In this review, we introduce the established methods and highlight the technical challenges associated with implementing each technique in a biological laboratory.

  15. Generation of monoclonal antibodies specific for cell surface molecules expressed on early mouse endoderm.

    PubMed

    Gadue, Paul; Gouon-Evans, Valerie; Cheng, Xin; Wandzioch, Ewa; Zaret, Kenneth S; Grompe, Markus; Streeter, Philip R; Keller, Gordon M

    2009-09-01

    The development of functional cell populations such as hepatocytes and pancreatic beta cells from embryonic stem cell (ESC) is dependent on the efficient induction of definitive endoderm early in the differentiation process. To monitor definitive endoderm formation in mouse ESC differentiation cultures in a quantitative fashion, we generated a reporter cell line that expresses human CD25 from the Foxa3 locus and human CD4 from the Foxa2 locus. Induction of these reporter ESCs with high concentrations of activin A led to the development of a CD25-Foxa3+CD4-Foxa2+ population within 4-5 days of culture. Isolation and characterization of this population showed that it consists predominantly of definitive endoderm that is able to undergo hepatic specification under the appropriate conditions. To develop reagents that can be used for studies on endoderm development from unmanipulated ESCs, from induced pluripotent stem cells, and from the mouse embryo, we generated monoclonal antibodies against the CD25-Foxa3+CD4-Foxa2+ population. With this approach, we identified two antibodies that react specifically with endoderm from ESC cultures and from the early embryo. The specificity of these antibodies enables one to quantitatively monitor endoderm development in ESC differentiation cultures, to study endoderm formation in the embryo, and to isolate pure populations of culture- or embryo-derived endodermal cells.

  16. Generation of retinal pigment epithelial cells from human embryonic stem cell-derived spherical neural masses.

    PubMed

    Cho, Myung Soo; Kim, Sang Jin; Ku, Seung-Yup; Park, Jung Hyun; Lee, Haksup; Yoo, Dae Hoon; Park, Un Chul; Song, Seul Ae; Choi, Young Min; Yu, Hyeong Gon

    2012-09-01

    Dysfunction and loss of retinal pigment epithelium (RPE) are major pathologic changes observed in various retinal degenerative diseases such as aged-related macular degeneration. RPE generated from human pluripotent stem cells can be a good candidate for RPE replacement therapy. Here, we show the differentiation of human embryonic stem cells (hESCs) toward RPE with the generation of spherical neural masses (SNMs), which are pure masses of hESCs-derived neural precursors. During the early passaging of SNMs, cystic structures arising from opened neural tube-like structures showed pigmented epithelial morphology. These pigmented cells were differentiated into functional RPE by neuroectodermal induction and mechanical purification. Most of the differentiated cells showed typical RPE morphologies, such as a polygonal-shaped epithelial monolayer, and transmission electron microscopy revealed apical microvilli, pigment granules, and tight junctions. These cells also expressed molecular markers of RPE, including Mitf, ZO-1, RPE65, CRALBP, and bestrophin. The generated RPE also showed phagocytosis of isolated bovine photoreceptor outer segment and secreting pigment epithelium-derived factor and vascular endothelial growth factor. Functional RPE could be generated from SNM in our method. Because SNMs have several advantages, including the capability of expansion for long periods without loss of differentiation capability, easy storage and thawing, and no need for feeder cells, our method for RPE differentiation may be used as an efficient strategy for generating functional RPE cells for retinal regeneration therapy.

  17. Rapid and robust generation of long-term self-renewing human neural stem cells with the ability to generate mature astroglia

    PubMed Central

    Palm, Thomas; Bolognin, Silvia; Meiser, Johannes; Nickels, Sarah; Träger, Claudia; Meilenbrock, Ralf-Leslie; Brockhaus, Johannes; Schreitmüller, Miriam; Missler, Markus; Schwamborn, Jens Christian

    2015-01-01

    Induced pluripotent stem cell bear the potential to differentiate into any desired cell type and hold large promise for disease-in-a-dish cell-modeling approaches. With the latest advances in the field of reprogramming technology, the generation of patient-specific cells has become a standard technology. However, directed and homogenous differentiation of human pluripotent stem cells into desired specific cell types remains an experimental challenge. Here, we report the development of a novel hiPSCs-based protocol enabling the generation of expandable homogenous human neural stem cells (hNSCs) that can be maintained under self-renewing conditions over high passage numbers. Our newly generated hNSCs retained differentiation potential as evidenced by the reliable generation of mature astrocytes that display typical properties as glutamate up-take and expression of aquaporin-4. The hNSC-derived astrocytes showed high activity of pyruvate carboxylase as assessed by stable isotope assisted metabolic profiling. Moreover, using a cell transplantation approach, we showed that grafted hNSCs were not only able to survive but also to differentiate into astroglial in vivo. Engraftments of pluripotent stem cells derived from somatic cells carry an inherent tumor formation potential. Our results demonstrate that hNSCs with self-renewing and differentiation potential may provide a safer alternative strategy, with promising applications especially for neurodegenerative disorders. PMID:26541394

  18. Pancreatic beta-cells: from generation to regeneration

    PubMed Central

    Collombat, Patrick; Xu, Xiaobo; Heimberg, Harry; Mansouri, Ahmed

    2010-01-01

    Summary The pancreas is composed of two main compartments consisting of endocrine and exocrine tissues. The majority of the organ is exocrine and responsible for the synthesis of digestive enzymes and for their transport via an intricate ductal system into the duodenum. The endocrine tissue represents less than 2% of the organ and is organized into functional units called islets of Langerhans, comprising alpha-, beta-, delta-, epsilon- and PP–cells, producing the hormones glucagon, insulin, somatostatin, ghrelin and pancreatic polypeptide (PP), respectively. Insulin-producing beta-cells play a central role in the control of the glucose homeostasis. Accordingly, absolute or relative deficiency in beta-cells may ultimately lead to type 1 and/or type 2 diabetes, respectively. One major goal of diabetes research is therefore to understand the molecular mechanisms controlling the development of beta-cells during pancreas morphogenesis, but also those underlying the regeneration of adult injured pancreas, and assess their significance for future cell-based therapy. In this review, we will therefore present new insights into beta-cell development with focus on beta-cell regeneration. PMID:20688184

  19. Generation of T cell effectors using tumor cell-loaded dendritic cells for adoptive T cell therapy.

    PubMed

    Vavrova, Katerina; Vrabcova, Petra; Filipp, Dominik; Bartunkova, Jirina; Horvath, Rudolf

    2016-12-01

    Adoptive T cell transfer has been shown to be an effective method used to boost tumor-specific immune responses in several types of malignancies. In this study, we set out to optimize the ACT protocol for the experimental treatment of prostate cancer. The protocol includes a pre-stimulation step whereby T cells were primed with autologous dendritic cells loaded with the high hydrostatic pressure-treated prostate cancer cell line, LNCaP. Primed T cells were further expanded in vitro with anti-CD3/CD28 Dynabeads in the WAVE bioreactor 2/10 system and tested for cytotoxicity. Our data indicates that the combination of pre-stimulation and expansion steps resulted in the induction and enrichment of tumor-responsive CD4(+) and CD8(+) T cells at clinically relevant numbers. The majority of both CD4(+) and CD8(+) IFN-γ producing cells were CD62L, CCR7 and CD57 negative but CD28 and CD27 positive, indicating an early antigen experienced phenotype in non-terminal differentiation phase. Expanded T cells showed significantly greater cytotoxicity against LNCaP cells compared to the control SKOV-3, an ovarian cancer line. In summary, our results suggest that the ACT approach together with LNCaP-loaded dendritic cells provides a viable way to generate prostate cancer reactive T cell effectors that are capable of mounting efficient and targeted antitumor responses and can be thus considered for further testing in a clinical setting.

  20. Co-transplantation of human hematopoietic stem cells and human breast cancer cells in NSG mice: a novel approach to generate tumor cell specific human antibodies.

    PubMed

    Wege, Anja K; Schmidt, Marcus; Ueberham, Elke; Ponnath, Marvin; Ortmann, Olaf; Brockhoff, Gero; Lehmann, Jörg

    2014-01-01

    Humanized tumor mice (HTM) were generated by the co-transplantation of human hematopoietic stem cells and human breast cancer cells overexpressing HER2 into neonatal NOD-scid IL2Rγ(null) (NSG) mice. These mice are characterized by the development of a human immune system in combination with human breast cancer growth. Due to concurrent transplantation into newborn mice, transfer of MHC-mismatched tumor cells resulted in solid coexistence and immune cell activation (CD4(+) T cells, natural killer cells, and myeloid cells), but without evidence for rejection. Histological staining of the spleen of HTM revealed co-localization of human antigen-presenting cells together with human T and B cells allowing MHC-dependent interaction, and thereby the generation of T cell-dependent antibody production. Here, we investigated the capability of these mice to generate human tumor-specific antibodies and correlated immunoglobulin titers with tumor outgrowth. We found detectable IgM and also IgG amounts in the serum of HTM, which apparently controlled tumor development when IgG serum concentrations were above 10 µg/ml. Western blot analyses revealed that the tumor-specific antibodies generated in HTM did not recognize HER2/neu antigens, but different, possibly relevant antigens for breast cancer therapy. In conclusion, HTM offer a novel approach to generate complete human monoclonal antibodies that do not require further genetic manipulation (e. g., humanization) for a potential application in humans. In addition, efficacy and safety of the generated antibodies can be tested in the same mouse model under human-like conditions. This might be of particular interest for cancer subtypes with no currently available antibody therapy.

  1. Ceramide Synthase-dependent Ceramide Generation and Programmed Cell Death

    PubMed Central

    Mullen, Thomas D.; Jenkins, Russell W.; Clarke, Christopher J.; Bielawski, Jacek; Hannun, Yusuf A.; Obeid, Lina M.

    2011-01-01

    The sphingolipid ceramide has been widely implicated in the regulation of programmed cell death or apoptosis. The accumulation of ceramide has been demonstrated in a wide variety of experimental models of apoptosis and in response to a myriad of stimuli and cellular stresses. However, the detailed mechanisms of its generation and regulatory role during apoptosis are poorly understood. We sought to determine the regulation and roles of ceramide production in a model of ultraviolet light-C (UV-C)-induced programmed cell death. We found that UV-C irradiation induces the accumulation of multiple sphingolipid species including ceramide, dihydroceramide, sphingomyelin, and hexosylceramide. Late ceramide generation was also found to be regulated by Bcl-xL, Bak, and caspases. Surprisingly, inhibition of de novo synthesis using myriocin or fumonisin B1 resulted in decreased overall cellular ceramide levels basally and in response to UV-C, but only fumonisin B1 inhibited cell death, suggesting the presence of a ceramide synthase (CerS)-dependent, sphingosine-derived pool of ceramide in regulating programmed cell death. We found that this pool did not regulate the mitochondrial pathway, but it did partially regulate activation of caspase-7 and, more importantly, was necessary for late plasma membrane permeabilization. Attempting to identify the CerS responsible for this effect, we found that combined knockdown of CerS5 and CerS6 was able to decrease long-chain ceramide accumulation and plasma membrane permeabilization. These data identify a novel role for CerS and the sphingosine salvage pathway in regulating membrane permeability in the execution phase of programmed cell death. PMID:21388949

  2. Development of Advanced Stirling Radioisotope Generator for Space Exploration

    NASA Technical Reports Server (NTRS)

    Chan, Jack; Wood, J. Gary; Schreiber, Jeffrey G.

    2007-01-01

    Under the joint sponsorship of the Department of Energy and NASA, a radioisotope power system utilizing Stirling power conversion technology is being developed for potential future space missions. The higher conversion efficiency of the Stirling cycle compared with that of Radioisotope Thermoelectric Generators (RTGs) used in previous missions (Viking, Pioneer, Voyager, Galileo, Ulysses, Cassini, and New Horizons) offers the advantage of a four-fold reduction in PuO2 fuel, thereby saving cost and reducing radiation exposure to support personnel. With the advancement of state-of-the-art Stirling technology development under the NASA Research Announcement (NRA) project, the Stirling Radioisotope Generator program has evolved to incorporate the advanced Stirling convertor (ASC), provided by Sunpower, into an engineering unit. Due to the reduced envelope and lighter mass of the ASC compared to the previous Stirling convertor, the specific power of the flight generator is projected to increase from 3.5 to 7 We/kg, along with a 25 percent reduction in generator length. Modifications are being made to the ASC design to incorporate features for thermal, mechanical, and electrical integration with the engineering unit. These include the heat collector for hot end interface, cold-side flange for waste heat removal and structural attachment, and piston position sensor for ASC control and power factor correction. A single-fault tolerant, active power factor correction controller is used to synchronize the Stirling convertors, condition the electrical power from AC to DC, and to control the ASCs to maintain operation within temperature and piston stroke limits. Development activities at Sunpower and NASA Glenn Research Center (GRC) are also being conducted on the ASC to demonstrate the capability for long life, high reliability, and flight qualification needed for use in future missions.

  3. Development of Advanced Stirling Radioisotope Generator for Space Exploration

    NASA Astrophysics Data System (ADS)

    Chan, Jack; Wood, J. Gary; Schreiber, Jeffrey G.

    2007-01-01

    Under the joint sponsorship of the Department of Energy and NASA, a radioisotope power system utilizing Stirling power conversion technology is being developed for potential future space missions. The higher conversion efficiency of the Stirling cycle compared with that of Radioisotope Thermoelectric Generators (RTGs) used in previous missions (Viking, Pioneer, Voyager, Galileo, Ulysses, Cassini, and New Horizons) offers the advantage of a four-fold reduction in PuO2 fuel, thereby saving cost and reducing radiation exposure to support personnel. With the advancement of state-of-the-art Stirling technology development under the NASA Research Announcement (NRA) project, the Stirling Radioisotope Generator program has evolved to incorporate the advanced Stirling convertor (ASC), provided by Sunpower, into an engineering unit. Due to the reduced envelope and lighter mass of the ASC compared to the previous Stirling convertor, the specific power of the flight generator is projected to increase from 3.5 We/kg to 7 We/kg, along with a 25% reduction in generator length. Modifications are being made to the ASC design to incorporate features for thermal, mechanical, and electrical integration with the engineering unit. These include the heat collector for hot end interface, cold-side flange for waste heat removal and structural attachment, and piston position sensor for ASC control and power factor correction. A single-fault tolerant, active power factor correction controller is used to synchronize the Stirling convertors, condition the electrical power from AC to DC, and to control the ASCs to maintain operation within temperature and piston stroke limits. Development activities at Sunpower and NASA Glenn Research Center (GRC) are also being conducted on the ASC to demonstrate the capability for long life, high reliability, and flight qualification needed for use in future missions.

  4. Developing Next Generation Natural Fracture Detection and Prediction Technology

    SciTech Connect

    R.L. Billingsley

    2005-05-01

    The purpose of the ''Next Generation'' project was to develop technology that will provide a quantitative description of natural fracture properties and locations in low-permeability reservoirs. The development of this technology has consistently been ranked as one of the highest priority needs by industry. Numerous researchers and resource assessment groups have stated that the ability to identify area where intense clusters of natural fractures co-exist with gas-charged sands, the so called ''sweet spots'', will be the key to unlocking the vast quantities of gas in-place contained in these low-permeability gas basins. To meet this technology need, the ''Next Generation'' project was undertaken with three performance criteria in mind: (1) provide an integrated assessment of the burial and tectonic stresses in a basin responsible for natural fracture genesis (using seismic data, a significantly modified application of geomechanics, and a discrete natural fracture generation model); (2) link the assessment of natural fracture properties and locations to the reservoir's fluid, storage and flow properties; and, (3) provide a reservoir simulation-based calculation of the gas (and water) production capacity of a naturally fractured reservoir system. Phase III of the ''Next Generation'' project entailed the performance of a field demonstration of the software in an ''exploration'' setting. The search for an Industry Partner willing to host an exploratory field demonstration was unsuccessful and Phase III was canceled effective May, 31, 2005. The failure to find an Industry Partner can be attributed to severe changes in the petroleum industry competitive environment between 1999 when the project was initiated and 2005 when further demonstration efforts were halted. The software was employed in portions of other, non-exploratory, projects underway during the development time period, and insights gained will be summarized here in lieu of a full field demonstration.

  5. Dynamics of vegetative cytoplasm during generative cell formation and pollen maturation in Arabidopsis thaliana

    NASA Technical Reports Server (NTRS)

    Kuang, A.; Musgrave, M. E.

    1996-01-01

    Ultrastructural changes of pollen cytoplasm during generative cell formation and pollen maturation in Arabidopsis thaliana were studied. The pollen cytoplasm develops a complicated ultrastructure and changes dramatically during these stages. Lipid droplets increase after generative cell formation and their organization and distribution change with the developmental stage. Starch grains in amyloplasts increase in number and size during generative and sperm cell formation and decrease at pollen maturity. The shape and membrane system of mitochondria change only slightly. Dictyosomes become very prominent, and numerous associated vesicles are observed during and after sperm cell formation. Endoplasmic reticulum appears extensively as stacks during sperm cell formation. Free and polyribosomes are abundant in the cytoplasm at all developmental stages although they appear denser at certain stages and in some areas. In mature pollen, all organelles are randomly distributed throughout the vegetative cytoplasm and numerous small particles appear. Organization and distribution of storage substances and appearance of these small particles during generative and sperm cell formation and pollen maturation are discussed.

  6. Dynamics of vegetative cytoplasm during generative cell formation and pollen maturation in Arabidopsis thaliana

    NASA Technical Reports Server (NTRS)

    Kuang, A.; Musgrave, M. E.

    1996-01-01

    Ultrastructural changes of pollen cytoplasm during generative cell formation and pollen maturation in Arabidopsis thaliana were studied. The pollen cytoplasm develops a complicated ultrastructure and changes dramatically during these stages. Lipid droplets increase after generative cell formation and their organization and distribution change with the developmental stage. Starch grains in amyloplasts increase in number and size during generative and sperm cell formation and decrease at pollen maturity. The shape and membrane system of mitochondria change only slightly. Dictyosomes become very prominent, and numerous associated vesicles are observed during and after sperm cell formation. Endoplasmic reticulum appears extensively as stacks during sperm cell formation. Free and polyribosomes are abundant in the cytoplasm at all developmental stages although they appear denser at certain stages and in some areas. In mature pollen, all organelles are randomly distributed throughout the vegetative cytoplasm and numerous small particles appear. Organization and distribution of storage substances and appearance of these small particles during generative and sperm cell formation and pollen maturation are discussed.

  7. Development of second-generation pressurized fluidized bed combustion process

    SciTech Connect

    Wolowodiuk, W.; Robertson, A.; Bonk, D.

    1995-12-01

    Under the sponsorship of the United States Department of Energy, Foster Wheeler Development Corporation, and its team members, Westinghouse, Gilbert/Commonwealth, and the Institute of Gas Technology are developing second-generation pressurized fluidized bed combustion technology capable of achieving net plant efficiency in excess of 45 percent based on the higher heating value of the coal. A three-phase program entails design and costing of a 500 MWe power plant and identification of developments needed to commercialize this technology (Phase 1), testing of individual components (Phase 2), and finally testing these components in an integrated mode (Phase 3). This paper briefly describes the results of the first two phases as well as the progress on the third phase. Since other projects which use the same technology are in construction or in negotiation stages-namely, the Power System Development Facility and the Four Rivers Energy Modernization Projects-brief descriptions of these are also included.

  8. Development, differentiation and manipulation of chicken germ cells.

    PubMed

    Nakamura, Yoshiaki; Kagami, Hiroshi; Tagami, Takahiro

    2013-01-01

    Germ cells are the only cell type capable of transmitting genetic information to the next generation. During development, they are set aside from all somatic cells of the embryo. In many species, germ cells form at the fringe of the embryo proper and then traverse through several developing somatic tissues on their migration to the emerging gonads. Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. Unlike other species, in avian embryos, PGCs use blood circulation for transport to the future gonadal region. This unique accessibility of avian PGCs during early development provides an opportunity to collect and transplant PGCs. The recent development of methods for production of germline chimeras by transfer of PGCs, and long-term cultivation methods of chicken PGCs without losing their germline transmission ability have provided important breakthroughs for the preservation of germplasm , for the production of transgenic birds and study the germ cell system. This review will describe the development, migration, differentiation and manipulation of germ cells, and discuss the prospects that germ cell technologies offer for agriculture, biotechnology and academic research. © 2013 The Authors Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

  9. Models of charge pair generation in organic solar cells.

    PubMed

    Few, Sheridan; Frost, Jarvist M; Nelson, Jenny

    2015-01-28

    Efficient charge pair generation is observed in many organic photovoltaic (OPV) heterojunctions, despite nominal electron-hole binding energies which greatly exceed the average thermal energy. Empirically, the efficiency of this process appears to be related to the choice of donor and acceptor materials, the resulting sequence of excited state energy levels and the structure of the interface. In order to establish a suitable physical model for the process, a range of different theoretical studies have addressed the nature and energies of the interfacial states, the energetic profile close to the heterojunction and the dynamics of excited state transitions. In this paper, we review recent developments underpinning the theory of charge pair generation and phenomena, focussing on electronic structure calculations, electrostatic models and approaches to excited state dynamics. We discuss the remaining challenges in achieving a predictive approach to charge generation efficiency.

  10. Sonic hedgehog acts cell-autonomously on muscle precursor cells to generate limb muscle diversity

    PubMed Central

    Anderson, Claire; Williams, Victoria C.; Moyon, Benjamin; Daubas, Philippe; Tajbakhsh, Shahragim; Buckingham, Margaret E.; Shiroishi, Toshihiko; Hughes, Simon M.; Borycki, Anne-Gaëlle

    2012-01-01

    How muscle diversity is generated in the vertebrate body is poorly understood. In the limb, dorsal and ventral muscle masses constitute the first myogenic diversification, as each gives rise to distinct muscles. Myogenesis initiates after muscle precursor cells (MPCs) have migrated from the somites to the limb bud and populated the prospective muscle masses. Here, we show that Sonic hedgehog (Shh) from the zone of polarizing activity (ZPA) drives myogenesis specifically within the ventral muscle mass. Shh directly induces ventral MPCs to initiate Myf5 transcription and myogenesis through essential Gli-binding sites located in the Myf5 limb enhancer. In the absence of Shh signaling, myogenesis is delayed, MPCs fail to migrate distally, and ventral paw muscles fail to form. Thus, Shh production in the limb ZPA is essential for the spatiotemporal control of myogenesis and coordinates muscle and skeletal development by acting directly to regulate the formation of specific ventral muscles. PMID:22987640

  11. Generation of Endoderm derived Human iPS cells from Primary Hepatocytes

    PubMed Central

    Liu, Hua; Ye, Zhaohui; Kim, Yong-Hak; Sharkis, Saul; Jang, Yoon-Young

    2010-01-01

    Recent advances in induced pluripotent stem (iPS) cell research significantly changed our perspective on regenerative medicine. Patient specific iPS cells have been derived not only for disease modeling but also as sources for cell replacement therapy. However, there have been insufficient data to prove that iPS cells are functionally equivalent to hES cells or safer than hES cells. There are several important issues which need to be addressed and foremost are the safety and efficacy of human iPS cells from different origins. Human iPS cells have been derived mostly from cells originated from mesoderm, with a few cases from ectoderm. So far there has been no report of endoderm derived human iPS cells, preventing comprehensive comparative investigations on the quality of human iPS cells from different origins. Here we show for the first time reprogramming of human endoderm derived cells (i.e. primary hepatocytes) to pluripotency. Hepatocyte-derived iPS cells appear indistinguishable from human embryonic stem cells in colony morphology, growth properties, expression of pluripotency-associated transcription factors and surface markers, and differentiation potential in embryoid body formation and teratoma assays. In addition, these cells were able to directly differentiate into definitive endoderm, hepatic progenitors, and mature hepatocytes. The technology to develop endoderm derived human iPS cell lines, together with other established cell lines, will provide a foundation to elucidate the mechanisms of cellular reprogramming and to study the safety and efficacy of differentially originated human iPS cells for cell therapy. For studying liver disease pathogenesis, this technology also provides a potentially more amenable system to generate liver disease specific iPS cells. PMID:20432258

  12. Fuel cells for power generation and waste treatment

    NASA Astrophysics Data System (ADS)

    Gair, S.; Cruden, A.; McDonald, J.; Hegarty, T.; Chesshire, M.

    It is now becoming increasingly clear that the in situ use of biomass and organic waste streams are likely to provide the key to energy self sustainability for islands and remote communities. Traditionally biofuels have been used in combustion engines for electric power generation, however, when replaced by fuel cells there is the prospect of achieving higher generating efficiencies, coupled with, in some instances, the opportunity to produce biofuel at a cheaper rate than conventional fuels. Additionally, important environmental benefits can be achieved by way of mitigating greenhouse gas emissions, whilst providing a carbon sink. This paper presents the design details of such an installation that will provide a practical solution on an island (and be applicable in other remote and rural areas) where connection to the grid can be expensive, and where biofuels can be produced on site at no significant extra cost.

  13. Generation and Characterization of JCV Permissive Hybrid Cell Lines

    PubMed Central

    Sariyer, Ilker K.; Safak, Mahmut; Gordon, Jennifer; Khalili, Kamel

    2009-01-01

    JC virus (JCV) is a human neurotropic polyomavirus whose replication in the central nervous system induces the fatal demyelinating disease, progressive multifocal leukoencephalopathy (PML). JCV particles have been detected primarily in oligodendrocytes and astrocytes of the brains of patients with PML and in the laboratory its propagation is limited to primary cultures of human fetal glial cells. In this short communication, the development of a new cell culture system is described through the fusion of primary human fetal astrocytes with the human glioblastoma cell line, U-87MG. The new hybrid cell line obtained from this fusion has the capacity to support efficiently expression of JCV and replication of viral DNA in vitro up to 16 passages. This cell line can serve as a reliable culture system to study the biology of JCV host cell interaction, determine the mechanisms involved in cell type specific replication of JCV, and provide a convenient cell culture system for high throughput screening of anti-viral agents. PMID:19442856

  14. Generation of Self-Renewing Hepatoblasts From Human Embryonic Stem Cells by Chemical Approaches.

    PubMed

    Zhang, Muzi; Sun, Pingxin; Wang, Yusheng; Chen, Junnan; Lv, Linjie; Wei, Wanguo; Jin, Caixia; Li, Wenlin

    2015-11-01

    Somatic stem cells play crucial roles in organogenesis and tissue homeostasis and regeneration and may ultimately prove useful for cell therapy for a variety of degenerative diseases and injuries; however, isolation and expansion of most types of somatic stem cells from tissues are technically challenging. Human pluripotent stem cells are a renewable source for any adult cell types, including somatic stem cells. Generation of somatic stem cells from human pluripotent stem cells is a promising strategy to get these therapeutically valuable cells. Previously, we developed a chemically defined condition for mouse hepatoblast self-renewal through a reiterative screening strategy. In the present study, we efficiently generated hepatoblasts from human embryonic stem cells by a stepwise induction strategy. Importantly, these human embryonic stem cell-derived hepatoblasts can be captured and stably maintained using conditions previously established for mouse hepatoblast self-renewal, which includes basal media supplemented with insulin, transferrin, sodium selenite, epidermal growth factor, glycogen synthase kinase 3 inhibitor, transforming growth factor β receptor inhibitor, lysophosphatidic acid, and sphingosine 1-phosphate. The cells can stably retain hepatoblast phenotypes during prolonged culture and can differentiate into mature hepatocytes through in vitro provision of hepatocyte lineage developmental cues. After being embedded into three-dimensional Matrigel, these cells efficiently formed bile duct-like structures resembling native bile duct tissues. These human embryonic stem cell-derived hepatoblasts would be useful as a renewable source for cell therapy of liver diseases. Somatic stem cells have been proposed as promising candidates for cell-based therapy; however, isolation of somatic stem cells from adult tissues is usually invasive and technically challenging. In the present study, hepatoblasts from human embryonic stem cells were efficiently generated

  15. On generating cell exemplars for detection of mitotic cells in breast cancer histopathology images.

    PubMed

    Aloraidi, Nada A; Sirinukunwattana, Korsuk; Khan, Adnan M; Rajpoot, Nasir M

    2014-01-01

    Mitotic activity is one of the main criteria that pathologists use to decide the grade of the cancer. Computerised mitotic cell detection promises to bring efficiency and accuracy into the grading process. However, detection and classification of mitotic cells in breast cancer histopathology images is a challenging task because of the large intra-class variation in the visual appearance of mitotic cells in various stages of cell division life cycle. In this paper, we test the hypothesis that cells in histopathology images can be effectively represented using cell exemplars derived from sub-images of various kinds of cells in an image for the purposes of mitotic cell classification. We compare three methods for generating exemplar cells. The methods have been evaluated in terms of classification performance on the MITOS dataset. The experimental results demonstrate that eigencells combined with support vector machines produce reasonably high detection accuracy among all the methods.

  16. CD4+ T cell anergy prevents autoimmunity and generates regulatory T cell precursors

    PubMed Central

    Kalekar, Lokesh A.; Schmiel, Shirdi E.; Nandiwada, Sarada L.; Lam, Wing Y.; Barsness, Laura O.; Zhang, Na; Stritesky, Gretta L.; Malhotra, Deepali; Pauken, Kristen E.; Linehan, Jonathan L.; O’Sullivan, M. Gerard; Fife, Brian T.; Hogquist, Kristin A.; Jenkins, Marc K.; Mueller, Daniel L.

    2015-01-01

    The role that anergy, an acquired state of T cell functional unresponsiveness, plays in natural peripheral tolerance remains unclear. In this study, we demonstrate that anergy is selectively induced in fetal antigen-specific maternal CD4+ T cells during pregnancy. A naturally occurring subpopulation of anergic polyclonal CD4+ T cells, enriched in self antigen-specific T cell receptors, is also observed in healthy hosts. Neuropilin-1 expression in anergic conventional CD4+ T cells is associated with thymic regulatory T cell (Treg cell)-related gene hypomethylation, and this correlates with their capacity to differentiate into Foxp3+ Treg cells that suppress immunopathology. Thus, our data suggest that not only is anergy induction important in preventing autoimmunity, but it also generates the precursors for peripheral Treg cell differentiation. PMID:26829766

  17. Generation of functional hepatocyte-like cells from human deciduous periodontal ligament stem cells.

    PubMed

    Vasanthan, Punitha; Jayaraman, Pukana; Kunasekaran, Wijenthiran; Lawrence, Anthony; Gnanasegaran, Nareshwaran; Govindasamy, Vijayendran; Musa, Sabri; Kasim, Noor Hayaty Abu

    2016-08-01

    Human deciduous periodontal ligament stem cells have been introduced for as an easily accessible source of stem cells from dental origin. Although recent studies have revealed the ability of these stem cells in multipotential attribute, their efficiency of hepatic lineage differentiation has not been addressed so far. The aim of this study is to investigate hepatic lineage fate competence of periodontal ligament stem cells through direct media induction. Differentiation of periodontal ligament stem cells into hepatocyte-like cells was conducted by the exposure of two phase media induction. First phase was performed in the presence of hepatocyte growth factors to induce a definitive endoderm formation. In the subsequent phase, the cells were treated with oncostatin M and dexamethosone followed by insulin and transferrin to generate hepatocyte-like cells. Hepatic-related characters of the generated hepatocyte-like cells were determined at both mRNA and protein level followed by functional assays. Foremost changes observed in the generation of hepatocyte-like cells were the morphological features in which these cells were transformed from fibroblastic shape to polygonal shape. Temporal expression of hepatic markers ranging from early endodermal up to late markers were detected in the hepatocyte-like cells. Crucial hepatic markers such as glycogen storage, albumin, and urea secretion were also shown. These findings exhibited the ability of periodontal ligament stem cells of dental origin to be directed into hepatic lineage fate. These cells can be regarded as an alternative autologous source in the usage of stem cell-based treatment for liver diseases.

  18. Generation of functional hepatocyte-like cells from human deciduous periodontal ligament stem cells

    NASA Astrophysics Data System (ADS)

    Vasanthan, Punitha; Jayaraman, Pukana; Kunasekaran, Wijenthiran; Lawrence, Anthony; Gnanasegaran, Nareshwaran; Govindasamy, Vijayendran; Musa, Sabri; Kasim, Noor Hayaty Abu

    2016-08-01

    Human deciduous periodontal ligament stem cells have been introduced for as an easily accessible source of stem cells from dental origin. Although recent studies have revealed the ability of these stem cells in multipotential attribute, their efficiency of hepatic lineage differentiation has not been addressed so far. The aim of this study is to investigate hepatic lineage fate competence of periodontal ligament stem cells through direct media induction. Differentiation of periodontal ligament stem cells into hepatocyte-like cells was conducted by the exposure of two phase media induction. First phase was performed in the presence of hepatocyte growth factors to induce a definitive endoderm formation. In the subsequent phase, the cells were treated with oncostatin M and dexamethosone followed by insulin and transferrin to generate hepatocyte-like cells. Hepatic-related characters of the generated hepatocyte-like cells were determined at both mRNA and protein level followed by functional assays. Foremost changes observed in the generation of hepatocyte-like cells were the morphological features in which these cells were transformed from fibroblastic shape to polygonal shape. Temporal expression of hepatic markers ranging from early endodermal up to late markers were detected in the hepatocyte-like cells. Crucial hepatic markers such as glycogen storage, albumin, and urea secretion were also shown. These findings exhibited the ability of periodontal ligament stem cells of dental origin to be directed into hepatic lineage fate. These cells can be regarded as an alternative autologous source in the usage of stem cell-based treatment for liver diseases.

  19. A developmentally plastic adult mouse kidney cell line spontaneously generates multiple adult kidney structures

    SciTech Connect

    Webb, Carol F.; Ratliff, Michelle L.; Powell, Rebecca; Wirsig-Wiechmann, Celeste R.; Lakiza, Olga; Obara, Tomoko

    2015-08-07

    Despite exciting new possibilities for regenerative therapy posed by the ability to induce pluripotent stem cells, recapitulation of three-dimensional kidneys for repair or replacement has not been possible. ARID3a-deficient mouse tissues generated multipotent, developmentally plastic cells. Therefore, we assessed the adult mouse ARID3a−/− kidney cell line, KKPS5, which expresses renal progenitor surface markers as an alternative cell source for modeling kidney development. Remarkably, these cells spontaneously developed into multicellular nephron-like structures in vitro, and engrafted into immunocompromised medaka mesonephros, where they formed mouse nephron structures. These data implicate KKPS5 cells as a new model system for studying kidney development. - Highlights: • An ARID3a-deficient mouse kidney cell line expresses multiple progenitor markers. • This cell line spontaneously forms multiple nephron-like structures in vitro. • This cell line formed mouse kidney structures in immunocompromised medaka fish kidneys. • Our data identify a novel model system for studying kidney development.

  20. Development of a vortex generator to perturb fish locomotion.

    PubMed

    Seth, Deeksha; Flammang, Brooke E; Lauder, George V; Tangorra, James L

    2017-03-15

    Knowledge about the stiffness of fish fins, and whether stiffness is modulated during swimming, is important for understanding the mechanics of a fin's force production. However, the mechanical properties of fins have not been studied during natural swimming, in part because of a lack of instrumentation. To remedy this, a vortex generator was developed that produces traveling vortices of adjustable strength which can be used to perturb the fins of swimming fish. Experiments were conducted to understand how the generator's settings affected the resulting vortex rings. A variety of vortices (14-32 mm diameter traveling at 371-2155 mm s(-1)) were produced that elicited adequate responses from the fish fins to help us to understand the fin's mechanical properties at various swimming speeds (0-350 mm s(-1)).

  1. The generation and antigen-specificity of CD4+CD25+ regulatory T cells.

    PubMed

    Taams, Leonie S; Curnow, S John; Vukmanovic-Stejic, M; Akbar, Arne N

    2006-09-01

    CD4+CD25+ regulatory T cells are essential components of the immune system. They help to maintain immune tolerance by exerting suppressive effects on cells of the adaptive and innate immune system. In the last few years there has been an abundance of papers addressing the suppressive effects of CD4+CD25+ regulatory T cells and their putative role in various experimental disease models and human diseases. Despite the enormous amounts of data on these cells a number of controversial issues still exists. CD4+CD25+ regulatory T cells were originally described as thymus-derived anergic/suppressive T cells. Recent papers however indicate that these cells might also be generated in the periphery. Due to the thymic development of CD4+CD25+ regulatory T cells it was thought that these cells were specific for self-antigens. Indeed it was shown that CD4+CD25+ regulatory T cells could be positively selected upon high affinity interaction with self-antigens. However, evidence is accumulating that these cells might also interact with non-self antigens. Finally, in the literature there is conflicting evidence regarding the role of soluble factors versus cell-contact in the mechanism of suppression. The aim of this review is to summarize the evidence supporting these opposing viewpoints and to combine them into a general model for the origin, function and antigen-specificity of CD4+CD25+ regulatory T cells.

  2. Spatial and Age-Dependent Hair Cell Generation in the Postnatal Mammalian Utricle.

    PubMed

    Gao, Zhen; Kelly, Michael C; Yu, Dehong; Wu, Hao; Lin, Xi; Chi, Fang-Lu; Chen, Ping

    2016-04-01

    Loss of vestibular hair cells is a common cause of balance disorders. Current treatment options for bilateral vestibular dysfunction are limited. During development, atonal homolog 1 (Atoh1) is sufficient and necessary for the formation of hair cells and provides a promising gene target to induce hair cell generation in the mammals. In this study, we used a transgenic mouse line to test the age and cell type specificity of hair cell induction in the postnatal utricle in mice. We found that forced Atoh1 expression in vivo can induce hair cell formation in the utricle from postnatal days 1 to 21, while the efficacy of hair cell induction is progressively reduced as the animals become older. In the utricle, the induction of hair cells occurs both within the sensory region and in cells in the transitional epithelium next to the sensory region. Within the sensory epithelium, the central region, known as the striola, is most subjective to the induction of hair cell formation. Furthermore, forced Atoh1 expression can promote proliferation in an age-dependent manner that mirrors the progressively reduced efficacy of hair cell induction in the postnatal utricle. These results suggest that targeting both cell proliferation and Atoh1 in the utricle striolar region may be explored to induce hair cell regeneration in mammals. The study also demonstrates the usefulness of the animal model that provides an in vivo Atoh1 induction model for vestibular regeneration studies.

  3. Interactions between zebrafish pigment cells responsible for the generation of Turing patterns

    PubMed Central

    Nakamasu, Akiko; Takahashi, Go; Kanbe, Akio; Kondo, Shigeru

    2009-01-01

    The reaction–diffusion system is one of the most studied nonlinear mechanisms that generate spatially periodic structures autonomous. On the basis of many mathematical studies using computer simulations, it is assumed that animal skin patterns are the most typical examples of the Turing pattern (stationary periodic pattern produced by the reaction–diffusion system). However, the mechanism underlying pattern formation remains unknown because the molecular or cellular basis of the phenomenon has yet to be identified. In this study, we identified the interaction network between the pigment cells of zebrafish, and showed that this interaction network possesses the properties necessary to form the Turing pattern. When the pigment cells in a restricted region were killed with laser treatment, new pigment cells developed to regenerate the striped pattern. We also found that the development and survival of the cells were influenced by the positioning of the surrounding cells. When melanophores and xanthophores were located at adjacent positions, these cells excluded one another. However, melanophores required a mass of xanthophores distributed in a more distant region for both differentiation and survival. Interestingly, the local effect of these cells is opposite to that of their effects long range. This relationship satisfies the necessary conditions required for stable pattern formation in the reaction–diffusion model. Simulation calculations for the deduced network generated wild-type pigment patterns as well as other mutant patterns. Our findings here allow further investigation of Turing pattern formation within the context of cell biology. PMID:19433782

  4. Electricity generation from macroalgae Enteromorpha prolifera hydrolysates using an alkaline fuel cell.

    PubMed

    Liu, Susu; Liu, Xianhua; Wang, Ying; Zhang, Pingping

    2016-12-01

    The goal of this work was to develop a method for the direct power generation using macroalgae Enteromorpha prolifera. The process conditions for the saccharification of macroalgae were optimized and a type of alkaline fuel cell contained no precious metal catalysts was developed. Under optimum conditions (170°C and 2% hydrochloric acid for 45min), dilute acid hydrolysis of the homogenized plants yielded 272.25g reducing sugar/kg dry algal biomass. The maximum power density reached 3.81W/m(2) under the condition of 3M KOH and 18.15g/L reducing sugar in hydrolysate, higher than any other reported algae-fed fuel cells. This study represents the first report on direct electricity generation from macroalgae using alkaline fuel cells, suggesting that there is great potential for the production of renewable energy using marine biomass.

  5. Microbial fuel cells - Applications for generation of electrical power and beyond.

    PubMed

    Mathuriya, Abhilasha Singh; Yakhmi, J V

    2016-01-01

    A Microbial Fuel Cell is a bioelectrochemical device that exploits metabolic activities of living microorganisms for generation of electric current. The usefulness and unique and exclusive architecture of this device has received wide attention recently of engineers and researchers of various disciplines such as microbiologists, chemical engineers, biotechnologists, environment engineers and mechanical engineers, and the subject of MFCs has thereby progressed as a well-developed technology. Sustained innovations and continuous development efforts have established the usefulness of MFCs towards many specialized and value-added applications beyond electricity generation, such as wastewater treatment and implantable body devices. This review is an attempt to provide an update on this rapidly growing technology.

  6. Somatic cell reprogramming-free generation of genetically modified pigs

    PubMed Central

    Tanihara, Fuminori; Takemoto, Tatsuya; Kitagawa, Eri; Rao, Shengbin; Do, Lanh Thi Kim; Onishi, Akira; Yamashita, Yukiko; Kosugi, Chisato; Suzuki, Hitomi; Sembon, Shoichiro; Suzuki, Shunichi; Nakai, Michiko; Hashimoto, Masakazu; Yasue, Akihiro; Matsuhisa, Munehide; Noji, Sumihare; Fujimura, Tatsuya; Fuchimoto, Dai-ichiro; Otoi, Takeshige

    2016-01-01

    Genetically modified pigs for biomedical applications have been mainly generated using the somatic cell nuclear transfer technique; however, this approach requires complex micromanipulation techniques and sometimes increases the risks of both prenatal and postnatal death by faulty epigenetic reprogramming of a donor somatic cell nucleus. As a result, the production of genetically modified pigs has not been widely applied. We provide a simple method for CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 gene editing in pigs that involves the introduction of Cas9 protein and single-guide RNA into in vitro fertilized zygotes by electroporation. The use of gene editing by electroporation of Cas9 protein (GEEP) resulted in highly efficient targeted gene disruption and was validated by the efficient production of Myostatin mutant pigs. Because GEEP does not require the complex methods associated with micromanipulation for somatic reprogramming, it has the potential for facilitating the genetic modification of pigs. PMID:27652340

  7. Somatic cell reprogramming-free generation of genetically modified pigs.

    PubMed

    Tanihara, Fuminori; Takemoto, Tatsuya; Kitagawa, Eri; Rao, Shengbin; Do, Lanh Thi Kim; Onishi, Akira; Yamashita, Yukiko; Kosugi, Chisato; Suzuki, Hitomi; Sembon, Shoichiro; Suzuki, Shunichi; Nakai, Michiko; Hashimoto, Masakazu; Yasue, Akihiro; Matsuhisa, Munehide; Noji, Sumihare; Fujimura, Tatsuya; Fuchimoto, Dai-Ichiro; Otoi, Takeshige

    2016-09-01

    Genetically modified pigs for biomedical applications have been mainly generated using the somatic cell nuclear transfer technique; however, this approach requires complex micromanipulation techniques and sometimes increases the risks of both prenatal and postnatal death by faulty epigenetic reprogramming of a donor somatic cell nucleus. As a result, the production of genetically modified pigs has not been widely applied. We provide a simple method for CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 gene editing in pigs that involves the introduction of Cas9 protein and single-guide RNA into in vitro fertilized zygotes by electroporation. The use of gene editing by electroporation of Cas9 protein (GEEP) resulted in highly efficient targeted gene disruption and was validated by the efficient production of Myostatin mutant pigs. Because GEEP does not require the complex methods associated with micromanipulation for somatic reprogramming, it has the potential for facilitating the genetic modification of pigs.

  8. Development of a synthetic vision display of the second generation

    NASA Astrophysics Data System (ADS)

    Smietanski, Guillaume; Lenhart, Peter M.; Kranz, Stephan; Mayer, Udo

    2000-06-01

    The Darmstadt University of Technology (TUD) develops displays with 3D terrain depiction to improve pilots spatial situation awareness. This will enhance safety and will lead to economical benefits by supporting new traffic procedures (i.e. SMGCS taxiing). Flight tests and simulation with a first generation of displays gave proof of the concept. However, for global usability it was necessary to rebuild the software concept. Displays of second generation utilise a worldwide database instead of a local and experimental one. With this new software concept either the database of the tools, to build it, should be certifiable. For performance reasons, logic information is included in the database. This means that the animation information about special objects is described in the database and not in the display software routines. This was the motivation to implement a new version of the software instead of an update of the first generation. A graphics library, written to build 3D graphic applications is used. This library makes optimal use of the graphic hardware and supports database. The new version provides a lot of flexibility, without decreasing the performance of the displays software. It is build for experimental research and not as a final product. The display format must have a lot of flexibility, because the software is contributing to different research projects in different configurations. It is also necessary to have a great flexibility for the interface configuration. Important steps in the development process of TUD's second generation Synthetic Vision Displays will be presented. Furthermore, features of the drawing process and the communication interface of the software will be explained.

  9. Mesenchymal stem cells in tumor development

    PubMed Central

    Cuiffo, Benjamin G.; Karnoub, Antoine E.

    2012-01-01

    Mesenchymal stem cells (MSCs) are multipotent progenitor cells that participate in the structural and functional maintenance of connective tissues under normal homeostasis. They also act as trophic mediators during tissue repair, generating bioactive molecules that help in tissue regeneration following injury. MSCs serve comparable roles in cases of malignancy and are becoming increasingly appreciated as critical components of the tumor microenvironment. MSCs home to developing tumors with great affinity, where they exacerbate cancer cell proliferation, motility, invasion and metastasis, foster angiogenesis, promote tumor desmoplasia and suppress anti-tumor immune responses. These multifaceted roles emerge as a product of reciprocal interactions occurring between MSCs and cancer cells and serve to alter the tumor milieu, setting into motion a dynamic co-evolution of both tumor and stromal tissues that favors tumor progression. Here, we summarize our current knowledge about the involvement of MSCs in cancer pathogenesis and review accumulating evidence that have placed them at the center of the pro-malignant tumor stroma. PMID:22863739

  10. Establishment of immortalized dental follicle cells for generating periodontal ligament in vivo.

    PubMed

    Yokoi, T; Saito, M; Kiyono, T; Iseki, S; Kosaka, K; Nishida, E; Tsubakimoto, T; Harada, H; Eto, K; Noguchi, T; Teranaka, T

    2007-02-01

    The dental follicle is a mesenchymal tissue that surrounds the developing tooth germ. During tooth root formation, periodontal components, viz., cementum, periodontal ligament (PDL), and alveolar bone, are created by dental follicle progenitors. Here, we report the presence of PDL progenitors in mouse dental follicle (MDF) cells. MDF cells were obtained from mouse incisor tooth germs and immortalized by the expression of a mutant human papilloma virus type 16 E6 gene lacking the PDZ-domain-binding motif. MDF cells expressing the mutant E6 gene (MDF( E6-EGFP ) cells) had an extended life span, beyond 150 population doublings (PD). In contrast, normal MDF cells failed to proliferate beyond 10 PD. MDF( E6-EGFP ) cells expressed tendon/ligament phenotype-related genes such as Scleraxis (Scx), growth and differentiation factor-5, EphA4, Six-1, and type I collagen. In addition, the expression of periostin was observed. To elucidate the differentiation capacity of MDF( E6-EGFP ) cells in vivo, the cells were transplanted into severe combined immunodeficiency mice. At 4 weeks, MDF( E6-EGFP ) cell transplants had the capacity to generate a PDL-like tissue that expressed periostin, Scx, and type XII collagen and the fibrillar assembly of type I collagen. Our findings suggest that MDF( E6-EGFP ) cells can act as PDL progenitors, and that these cells may be a useful research tool for studying PDL formation and for developing regeneration therapies.

  11. In Vitro T-Cell Generation From Adult, Embryonic, and Induced Pluripotent Stem Cells: Many Roads to One Destination.

    PubMed

    Smith, Michelle J; Webber, Beau R; Mohtashami, Mahmood; Stefanski, Heather E; Zúñiga-Pflücker, Juan Carlos; Blazar, Bruce R

    2015-11-01

    T lymphocytes are critical mediators of the adaptive immune system and have the capacity to serve as therapeutic agents in the areas of transplant and cancer immunotherapy. While T cells can be isolated and expanded from patients, T cells derived in vitro from both hematopoietic stem/progenitor cells (HSPCs) and human pluripotent stem cells (hPSCs) offer great potential advantages in generating a self-renewing source of T cells that can be readily genetically modified. T-cell differentiation in vivo is a complex process requiring tightly regulated signals; providing the correct signals in vitro to induce T-cell lineage commitment followed by their development into mature, functional, single positive T cells, is similarly complex. In this review, we discuss current methods for the in vitro derivation of T cells from murine and human HSPCs and hPSCs that use feeder-cell and feeder-cell-free systems. Furthermore, we explore their potential for adoption for use in T-cell-based therapies.

  12. Photovoltaic power conditioners: Development, evolution, and the next generation

    SciTech Connect

    Bulawka, A.; Krauthamer, S.; Das, R.; Bower, W.

    1994-07-01

    Market-place acceptance of utility-connected photovoltaic (PV) power generation systems and their accelerated installation into residential and commercial applications are heavily dependent upon the ability of their power conditioning subsystems (PCS) to meet high reliability, low cost, and high performance goals. Many PCS development efforts have taken place over the last 15 years, and those efforts have resulted in substantial PCS hardware improvements. These improvements, however, have generally fallen short of meeting many reliability, cost and performance goals. Continuously evolving semiconductor technology developments, coupled with expanded market opportunities for power processing, offer a significant promise of improving PCS reliability, cost and performance, as they are integrated into future PCS designs. This paper revisits past and present development efforts in PCS design, identifies the evolutionary improvements and describes the new opportunities for PCS designs. The new opportunities are arising from the increased availability and capability of semiconductor switching components, smart power devices, and power integrated circuits (PICS).

  13. Scientific and Technical Development of the Next Generation Space Telescope

    NASA Technical Reports Server (NTRS)

    Burg, Richard

    2003-01-01

    The Next Generation Space Telescope (NGST) is part of the Origins program and is the key mission to discover the origins of galaxies in the Universe. It is essential that scientific requirements be translated into technical specifications at the beginning of the program and that there is technical participation by astronomers in the design and modeling of the observatory. During the active time period of this grant, the PI participated in the NGST program at GSFC by participating in the development of the Design Reference Mission, the development of the full end-to-end model of the observatory, the design trade-off based on the modeling, the Science Instrument Module definition and modeling, the study of proto-mission and test-bed development, and by participating in meetings including quarterly reviews and support of the NGST SWG. This work was documented in a series of NGST Monographs that are available on the NGST web site.

  14. Fetal programming of infant neuromotor development: the generation R study.

    PubMed

    van Batenburg-Eddes, Tamara; de Groot, Laila; Steegers, Eric A P; Hofman, Albert; Jaddoe, Vincent W V; Verhulst, Frank C; Tiemeier, Henning

    2010-02-01

    The objective of the study was to examine whether infant neuromotor development is determined by fetal size and body symmetry in the general population. This study was embedded within the Generation R Study, a population-based cohort in Rotterdam. In 2965 fetuses, growth parameters were measured in mid-pregnancy and late pregnancy. After birth, at age 9 to 15 wks, neuromotor development was assessed with an adapted version of Touwen's Neurodevelopmental Examination. Less optimal neuromotor development was defined as a score in the highest tertile. We found that higher fetal weight was beneficial to infant neurodevelopment. A fetus with a 1-SD score higher weight in mid-pregnancy had an 11% lower risk of less optimal neuromotor development (OR: 0.89; 95% CI: 0.82-0.97). Similarly, a fetus with a 1-SD score larger abdominal-to-head circumference (AC/HC) ratio had a 13% lower risk of less optimal neuromotor development (OR: 0.87; 95% CI: 0.79-0.96). These associations were also present in late pregnancy. Our findings show that fetal size and body symmetry in pregnancy are associated with infant neuromotor development. These results suggest that differences in infant neuromotor development, a marker of behavioral and cognitive problems, are at least partly caused by processes occurring early in fetal life.

  15. Generation of cancer stem-like cells through the formation of polyploid giant cancer cells.

    PubMed

    Zhang, S; Mercado-Uribe, I; Xing, Z; Sun, B; Kuang, J; Liu, J

    2014-01-02

    Polyploid giant cancer cells (PGCCs) have been observed by pathologists for over a century. PGCCs contribute to solid tumor heterogeneity, but their functions are largely undefined. Little attention has been given to these cells, largely because PGCCs have been generally thought to originate from repeated failure of mitosis/cytokinesis and have no capacity for long-term survival or proliferation. Here we report our successful purification and culture of PGCCs from human ovarian cancer cell lines and primary ovarian cancer. These cells are highly resistant to oxygen deprivation and could form through endoreduplication or cell fusion, generating regular-sized cancer cells quickly through budding or bursting similar to simple organisms like fungi. They express normal and cancer stem cell markers, they divide asymmetrically and they cycle slowly. They can differentiate into adipose, cartilage and bone. A single PGCC formed cancer spheroids in vitro and generated tumors in immunodeficient mice. These PGCC-derived tumors gained a mesenchymal phenotype with increased expression of cancer stem cell markers CD44 and CD133 and become more resistant to treatment with cisplatin. Taken together, our results reveal that PGCCs represent a resistant form of human cancer using an ancient, evolutionarily conserved mechanism in response to hypoxia stress; they can contribute to the generation of cancer stem-like cells, and also play a fundamental role in regulating tumor heterogeneity, tumor growth and chemoresistance in human cancer.

  16. Development and dynamics of cell polarity at a glance.

    PubMed

    Campanale, Joseph P; Sun, Thomas Y; Montell, Denise J

    2017-04-01

    Cells exhibit morphological and molecular asymmetries that are broadly categorized as cell polarity. The cell polarity established in early embryos prefigures the macroscopic anatomical asymmetries characteristic of adult animals. For example, eggs and early embryos have polarized distributions of RNAs and proteins that generate global anterior/posterior and dorsal/ventral axes. The molecular programs that polarize embryos are subsequently reused in multiple contexts. Epithelial cells require apical/basal polarity to establish their barrier function. Migrating cells polarize in the direction of movement, creating distinct leading and trailing structures. Asymmetrically dividing stem cells partition different molecules between themselves and their daughter cells. Cell polarity can develop de novo, be maintained through rounds of cell division and be dynamically remodeled. In this Cell Science at a Glance review and poster, we describe molecular asymmetries that underlie cell polarity in several cellular contexts. We highlight multiple developmental systems that first establish cell/developmental polarity, and then maintain it. Our poster showcases repeated use of the Par, Scribble and Crumbs polarity complexes, which drive the development of cell polarity in many cell types and organisms. We then briefly discuss the diverse and dynamic changes in cell polarity that occur during cell migration, asymmetric cell division and in planar polarized tissues.

  17. New-generation mass spectrometry expands the toolbox of cell and developmental biology.

    PubMed

    Lombard-Banek, Camille; Portero, Erika P; Onjiko, Rosemary M; Nemes, Peter

    2017-01-01

    Systems cell biology understanding of development requires characterization of all the molecules produced in the biological system. Decades of research and new-generation sequencing provided functional information on key genes and transcripts. However, there is less information available on how differential gene expression translates into the domains of functionally important proteins, peptides, and metabolites, and how changes in these molecules impact development. Mass spectrometry (MS) is the current technology of choice for the detection and quantification of large numbers of proteins and metabolites, because it requires no use of antibodies, functional probes, or a priori knowledge of molecules produced in the system. This review focuses on recent technologies that have improved MS sensitivity for proteins and metabolites and enabled new functionalities to assess their temporal and spatial changes during vertebrate embryonic development. This review highlights case studies, in which new-generation MS tools have enabled the study of hundreds-to-thousands of proteins and metabolites in tissues, cell populations, and single cells in model systems of vertebrate development, particularly the frog (Xenopus), zebrafish, and mouse. New-generation MS expands the toolbox of cell and developmental studies, raising exciting potentials to advance basic and translational research in the life sciences. © 2017 Wiley Periodicals, Inc.

  18. Optofluidics based micro-photocatalytic fuel cell for efficient wastewater treatment and electricity generation.

    PubMed

    Li, Lin; Wang, Guanyi; Chen, Rong; Zhu, Xun; Wang, Hong; Liao, Qiang; Yu, Youxu

    2014-09-07

    In this work, an optofluidics based micro-photocatalytic fuel cell with a membrane-free and air-breathing mode was proposed to greatly enhance the cell performance. The incorporation of the optofluidic technology into a photocatalytic fuel cell not only enlarges the specific illumination and reaction area but also enhances the photon and mass transfer, which eventually boosts the photocatalytic reaction rate. Our results show that this new photocatalytic fuel cell yields a much higher performance in converting organics into electricity. A maximum power density of 0.58 mW cm(-2) was achieved. The degradation performance of this new optofluidic micro-photocatalytic fuel cell was also evaluated and the maximum degradation efficiency reached 83.9%. In short, the optofluidic micro-photocatalytic fuel cell developed in this work shows promising potential for simultaneously degrading organic pollutants and generating electricity.

  19. Human Cord Blood and Bone Marrow CD34+ Cells Generate Macrophages That Support Erythroid Islands

    PubMed Central

    Belay, Eyayu; Hayes, Brian J.; Blau, C. Anthony; Torok-Storb, Beverly

    2017-01-01

    Recently, we developed a small molecule responsive hyperactive Mpl-based Cell Growth Switch (CGS) that drives erythropoiesis associated with macrophages in the absence of exogenous cytokines. Here, we compare the physical, cellular and molecular interaction between the macrophages and erythroid cells in CGS expanded CD34+ cells harvested from cord blood, marrow or G-CSF-mobilized peripheral blood. Results indicated that macrophage based erythroid islands could be generated from cord blood and marrow CD34+ cells but not from G-CSF-mobilized CD34+ cells. Additional studies suggest that the deficiency resides with the G-CSF-mobilized CD34+ derived monocytes. Gene expression and proteomics studies of the in vitro generated erythroid islands detected the expression of erythroblast macrophage protein (EMP), intercellular adhesion molecule 4 (ICAM-4), CD163 and DNASE2. 78% of the erythroblasts in contact with macrophages reached the pre reticulocyte orthochromatic stage of differentiation within 14 days of culture. The addition of conditioned medium from cultures of CD146+ marrow fibroblasts resulted in a 700-fold increase in total cell number and a 90-fold increase in erythroid cell number. This novel CD34+ cell derived erythroid island may serve as a platform to explore the molecular basis of red cell maturation and production under normal, stress and pathological conditions. PMID:28135323

  20. Combustion Stability Analyses for J-2X Gas Generator Development

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.; Protz, C. S.; Casiano, M. J.; Kenny, R. J.

    2010-01-01

    The National Aeronautics and Space Administration (NASA) is developing a liquid oxygen/liquid hydrogen rocket engine for upper stage and trans-lunar applications of the Ares vehicles for the Constellation program. This engine, designated the J-2X, is a higher pressure, higher thrust variant of the Apollo-era J-2 engine. Development was contracted to Pratt & Whitney Rocketdyne in 2006. Over the past several years, development of the gas generator for the J-2X engine has progressed through a variety of workhorse injector, chamber, and feed system configurations. Several of these configurations have resulted in injection-coupled combustion instability of the gas generator assembly at the first longitudinal mode of the combustion chamber. In this paper, the longitudinal mode combustion instabilities observed on the workhorse test stand are discussed in detail. Aspects of this combustion instability have been modeled at the NASA Marshall Space Flight Center with several codes, including the Rocket Combustor Interaction Design and Analysis (ROCCID) code and a new lumped-parameter MatLab model. To accurately predict the instability characteristics of all the chamber and injector geometries and test conditions, several features of the submodels in the ROCCID suite of calculations required modification. Finite-element analyses were conducted of several complicated combustion chamber geometries to determine how to model and anchor the chamber response in ROCCID. A large suite of sensitivity calculations were conducted to determine how to model and anchor the injector response in ROCCID. These modifications and their ramification for future stability analyses of this type are discussed in detail. The lumped-parameter MatLab model of the gas generator assembly was created as an alternative calculation to the ROCCID methodology. This paper also describes this model and the stability calculations.