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Sample records for alveolar ti cell

  1. Repopulation of denuded tracheal grafts with alveolar type II cells

    International Nuclear Information System (INIS)

    Johnson, N.F.

    1988-01-01

    Repopulation of denuded heterotopic tracheal grafts with populations of specific epithelial cell types is one approach to study the differentiation potential of various cell types. This technique has been adopted to delineate the differentiation pathways of alveolar type II cells isolated from rat lungs. Under the conditions of this experiment, the reestablished epithelial lining was alveolar-like, however, ultrastructural analysis of the cells showed them to be like Clara cells. These preliminary results suggest that the secretary cells of the lung parenchyma and terminal airways may share a common ancestry. (author)

  2. Modeling Alveolar Epithelial Cell Behavior In Spatially Designed Hydrogel Microenvironments

    Science.gov (United States)

    Lewis, Katherine Jean Reeder

    The alveolar epithelium consists of two cell phenotypes, elongated alveolar type I cells (AT1) and rounded alveolar type II cells (ATII), and exists in a complex three-dimensional environment as a polarized cell layer attached to a thin basement membrane and enclosing a roughly spherical lumen. Closely surrounding the alveolar cysts are capillary endothelial cells as well as interstitial pulmonary fibroblasts. Many factors are thought to influence alveolar epithelial cell differentiation during lung development and wound repair, including physical and biochemical signals from the extracellular matrix (ECM), and paracrine signals from the surrounding mesenchyme. In particular, disrupted signaling between the alveolar epithelium and local fibroblasts has been implicated in the progression of several pulmonary diseases. However, given the complexity of alveolar tissue architecture and the multitude of signaling pathways involved, designing appropriate experimental platforms for this biological system has been difficult. In order to isolate key factors regulating cellular behavior, the researcher ideally should have control over biophysical properties of the ECM, as well as the ability to organize multiple cell types within the scaffold. This thesis aimed to develop a 3D synthetic hydrogel platform to control alveolar epithelial cyst formation, which could then be used to explore how extracellular cues influence cell behavior in a tissue-relevant cellular arrangement. To accomplish this, a poly(ethylene glycol) (PEG) hydrogel network containing enzymatically-degradable crosslinks and bioadhesive pendant peptides was employed as a base material for encapsulating primary alveolar epithelial cells. First, an array of microwells of various cross-sectional shapes was photopatterned into a PEG gel containing photo-labile crosslinks, and primary ATII cells were seeded into the wells to examine the role of geometric confinement on differentiation and multicellular arrangement

  3. The development and plasticity of alveolar type 1 cells

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    Yang, Jun; Hernandez, Belinda J.; Martinez Alanis, Denise; Narvaez del Pilar, Odemaris; Vila-Ellis, Lisandra; Akiyama, Haruhiko; Evans, Scott E.; Ostrin, Edwin J.; Chen, Jichao

    2016-01-01

    Alveolar type 1 (AT1) cells cover >95% of the gas exchange surface and are extremely thin to facilitate passive gas diffusion. The development of these highly specialized cells and its coordination with the formation of the honeycomb-like alveolar structure are poorly understood. Using new marker-based stereology and single-cell imaging methods, we show that AT1 cells in the mouse lung form expansive thin cellular extensions via a non-proliferative two-step process while retaining cellular plasticity. In the flattening step, AT1 cells undergo molecular specification and remodel cell junctions while remaining connected to their epithelial neighbors. In the folding step, AT1 cells increase in size by more than 10-fold and undergo cellular morphogenesis that matches capillary and secondary septa formation, resulting in a single AT1 cell spanning multiple alveoli. Furthermore, AT1 cells are an unexpected source of VEGFA and their normal development is required for alveolar angiogenesis. Notably, a majority of AT1 cells proliferate upon ectopic SOX2 expression and undergo stage-dependent cell fate reprogramming. These results provide evidence that AT1 cells have both structural and signaling roles in alveolar maturation and can exit their terminally differentiated non-proliferative state. Our findings suggest that AT1 cells might be a new target in the pathogenesis and treatment of lung diseases associated with premature birth. PMID:26586225

  4. Carbon black nanoparticles induce type II epithelial cells to release chemotaxins for alveolar macrophages

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    Donaldson Ken

    2005-12-01

    Full Text Available Abstract Background Alveolar macrophages are a key cell in dealing with particles deposited in the lungs and in determining the subsequent response to that particle exposure. Nanoparticles are considered a potential threat to the lungs and the mechanism of pulmonary response to nanoparticles is currently under intense scrutiny. The type II alveolar epithelial cell has previously been shown to release chemoattractants which can recruit alveolar macrophages to sites of particle deposition. The aim of this study was to assess the responses of a type II epithelial cell line (L-2 to both fine and nanoparticle exposure in terms of secretion of chemotactic substances capable of inducing macrophage migration. Results Exposure of type II cells to carbon black nanoparticles resulted in significant release of macrophage chemoattractant compared to the negative control and to other dusts tested (fine carbon black and TiO2 and nanoparticle TiO2 as measured by macrophage migration towards type II cell conditioned medium. SDS-PAGE analysis of the conditioned medium from particle treated type II cells revealed that a higher number of protein bands were present in the conditioned medium obtained from type II cells treated with nanoparticle carbon black compared to other dusts tested. Size-fractionation of the chemotaxin-rich supernatant determined that the chemoattractants released from the epithelial cells were between 5 and 30 kDa in size. Conclusion The highly toxic nature and reactive surface chemistry of the carbon black nanoparticles has very likely induced the type II cell line to release pro-inflammatory mediators that can potentially induce migration of macrophages. This could aid in the rapid recruitment of inflammatory cells to sites of particle deposition and the subsequent removal of the particles by phagocytic cells such as macrophages and neutrophils. Future studies in this area could focus on the exact identity of the substance(s released by the

  5. Human alveolar bone cell proliferation, expression of osteoblastic phenotype, and matrix mineralization on porous titanium produced by powder metallurgy.

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    Rosa, Adalberto Luiz; Crippa, Grasiele Edilaine; de Oliveira, Paulo Tambasco; Taba, Mario; Lefebvre, Louis-Philippe; Beloti, Marcio Mateus

    2009-05-01

    This study aimed at investigating the influence of the porous titanium (Ti) structure on the osteogenic cell behaviour. Porous Ti discs were fabricated by the powder metallurgy process with the pore size typically between 50 and 400 microm and a porosity of 60%. Osteogenic cells obtained from human alveolar bone were cultured until subconfluence and subcultured on dense Ti (control) and porous Ti for periods of up to 17 days. Cultures grown on porous Ti exhibited increased cell proliferation and total protein content, and lower levels of alkaline phosphatase (ALP) activity than on dense Ti. In general, gene expression of osteoblastic markers-runt-related transcription factor 2, collagen type I, alkaline phosphatase, bone morphogenetic protein-7, and osteocalcin was lower at day 7 and higher at day 17 in cultures grown on porous Ti compared with dense Ti, a finding consistent with the enhanced growth rate for such cultures. The amount of mineralized matrix was greater on porous Ti compared with the dense one. These results indicate that the porous Ti is an appropriate substrate for osteogenic cell adhesion, proliferation, and production of a mineralized matrix. Because of the three-dimensional environment it provides, porous Ti should be considered an advantageous substrate for promoting desirable implant surface-bone interactions.

  6. Alveolar cell carcinoma: diagnostic pitfalls in evaluating the chest roentgenogram

    International Nuclear Information System (INIS)

    Shin, M.S.; Bailey, W.C.

    1985-01-01

    A report is given of two patients with initial symptoms of congestive heart failure who had an extensive work-up that failed to reveal any signs of pulmonary malignancy. Subsequent biopsy by fiberoptic bronchoscopy confirmed alveolar cell carcinoma in both cases, suggesting that bronchoscopy with biopsy should be considered in patients with congestive heart failure if pulmonary edema does not resolve with appropriate therapy. 11 references, 2 figures

  7. Metabolic shift in lung alveolar cell mitochondria following acrolein exposure.

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    Agarwal, Amit R; Yin, Fei; Cadenas, Enrique

    2013-11-15

    Acrolein, an α,β unsaturated electrophile, is an environmental pollutant released in ambient air from diesel exhausts and cooking oils. This study examines the role of acrolein in altering mitochondrial function and metabolism in lung-specific cells. RLE-6TN, H441, and primary alveolar type II (pAT2) cells were exposed to acrolein for 4 h, and its effect on mitochondrial oxygen consumption rates was studied by XF Extracellular Flux analysis. Low-dose acrolein exposure decreased mitochondrial respiration in a dose-dependent manner because of alteration in the metabolism of glucose in all the three cell types. Acrolein inhibited glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity, leading to decreased substrate availability for mitochondrial respiration in RLE-6TN, H441, and pAT2 cells; the reduced GAPDH activity was compensated in pAT2 cells by an increase in the activity of glucose-6-phosphate dehydrogenase, the regulatory control of the pentose phosphate pathway. The decrease in pyruvate from glucose metabolism resulted in utilization of alternative sources to support mitochondrial energy production: palmitate-BSA complex increased mitochondrial respiration in RLE-6TN and pAT2 cells. The presence of palmitate in alveolar cells for surfactant biosynthesis may prove to be the alternative fuel source for mitochondrial respiration. Accordingly, a decrease in phosphatidylcholine levels and an increase in phospholipase A2 activity were found in the alveolar cells after acrolein exposure. These findings have implications for understanding the decrease in surfactant levels frequently observed in pathophysiological situations with altered lung function following exposure to environmental toxicants.

  8. Alveolar type II epithelial cell dysfunction in rat experimental hepatopulmonary syndrome (HPS.

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    Wenli Yang

    Full Text Available The hepatopulmonary syndrome (HPS develops when pulmonary vasodilatation leads to abnormal gas exchange. However, in human HPS, restrictive ventilatory defects are also observed supporting that the alveolar epithelial compartment may also be affected. Alveolar type II epithelial cells (AT2 play a critical role in maintaining the alveolar compartment by producing four surfactant proteins (SPs, SP-A, SP-B, SP-C and SP-D which also facilitate alveolar repair following injury. However, no studies have evaluated the alveolar epithelial compartment in experimental HPS. In this study, we evaluated the alveolar epithelial compartment and particularly AT2 cells in experimental HPS induced by common bile duct ligation (CBDL. We found a significant reduction in pulmonary SP production associated with increased apoptosis in AT2 cells after CBDL relative to controls. Lung morphology showed decreased mean alveolar chord length and lung volumes in CBDL animals that were not seen in control models supporting a selective reduction of alveolar airspace. Furthermore, we found that administration of TNF-α, the bile acid, chenodeoxycholic acid, and FXR nuclear receptor activation (GW4064 induced apoptosis and impaired SP-B and SP-C production in alveolar epithelial cells in vitro. These results imply that AT2 cell dysfunction occurs in experimental HPS and is associated with alterations in the alveolar epithelial compartment. Our findings support a novel contributing mechanism in experimental HPS that may be relevant to humans and a potential therapeutic target.

  9. Characterization of immortalized MARCO and SR-AI/II-deficient murine alveolar macrophage cell lines

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    Imrich Amy

    2008-05-01

    Full Text Available Abstract Background Alveolar macrophages (AM avidly bind and ingest unopsonized inhaled particles and bacteria through class A scavenger receptors (SRAs MARCO and SR-AI/II. Studies to characterize the function of these SRAs have used AMs from MARCO or SR-AI/II null mice, but this approach is limited by the relatively low yield of AMs. Moreover, studies using both MARCO and SR-AI/II-deficient (MS-/- mice have not been reported yet. Hence, we sought to develop continuous cell lines from primary alveolar macrophages from MS-/- mice. Results We used in vitro infection of the primary AMs with the J2 retrovirus carrying the v-raf and v-myc oncogenes. Following initial isolation in media supplemented with murine macrophage colony-stimulating factor (M-CSF, we subcloned three AM cell lines, designated ZK-1, ZK-2 and ZK-6. These cell lines grow well in RPMI-1640-10% FBS in the absence of M-CSF. These adherent but trypsin-sensitive cell lines have a doubling time of approximately 14 hours, exhibit typical macrophage morphology, and express macrophage-associated cell surface Mac-1 (CD11b and F4/80 antigens. The cell lines show robust Fc-receptor dependent phagocytosis of opsonized red blood cells. Similar to freshly isolated AMs from MS-/- mice, the cell lines exhibit decreased phagocytosis of unopsonized titanium dioxide (TiO2, fluorescent latex beads and bacteria (Staphylococcus aureus compared with the primary AMs from wild type (WT C57BL/6 mice. Conclusion Our results indicated that three contiguous murine alveolar macrophage cell lines with MS-/- (ZK1, ZK2 and ZK6 were established successfully. These cell lines demonstrated macrophage morphology and functional activity. Interestingly, similar to freshly isolated AMs from MS-/- mice, the cell lines have a reduced, but not absent, ability to bind and ingest particles, with an altered pattern of blockade by scavenger receptor inhibitors. These cell lines will facilitate in vitro studies to further define

  10. The Milieu of Damaged Alveolar Epithelial Type 2 Cells Stimulates Alveolar Wound Repair by Endogenous and Exogenous Progenitors

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    Buckley, Susan; Shi, Wei; Carraro, Gianni; Sedrakyan, Sargis; Da Sacco, Stefano; Driscoll, Barbara A.; Perin, Laura; De Filippo, Roger E.

    2011-01-01

    Alveolar epithelial integrity is dependent upon the alveolar milieu, yet the milieu of the damaged alveolar epithelial cell type 2 (AEC2) has been little studied. Characterization of its components may offer the potential for ex vivo manipulation of stem cells to optimize their therapeutic potential. We examined the cytokine profile of AEC2 damage milieu, hypothesizing that it would promote endogenous epithelial repair while recruiting cells from other locations and instructing their engraftment and differentiation. Bronchoalveolar lavage and lung extract from hyperoxic rats represented AEC2 in vivo damage milieu, and medium from a scratch-damaged AEC2 monolayer represented in vitro damage. CINC-2 and ICAM, the major cytokines detected by proteomic cytokine array in AEC2 damage milieu, were chemoattractive to normoxic AECs and expedited in vitro wound healing, which was blocked by their respective neutralizing antibodies. The AEC2 damage milieu was also chemotactic for exogenous uncommitted human amniotic fluid stem cells (hAFSCs), increasing migration greater than 20-fold. hAFSCs attached within an in vitro AEC2 wound and expedited wound repair by contributing cytokines migration inhibitory factor and plasminogen activator inhibitor 1 to the AEC2 damage milieu, which promoted wound healing. The AEC2 damage milieu also promoted differentiation of a subpopulation of hAFSCs to express SPC, TTF-1, and ABCA3, phenotypic markers of distal alveolar epithelium. Thus, the microenvironment created by AEC2 damage not only promotes autocrine repair but also can attract uncommitted stem cells, which further augment healing through cytokine secretion and differentiation. PMID:21700959

  11. HES6 enhances the motility of alveolar rhabdomyosarcoma cells

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    Wickramasinghe, Caroline M [MRC Cancer Cell Unit, Hutchison-MRC Research centre, Addenbrooke' s Hospital Cambridge, CB2 0XZ (United Kingdom); MRC Laboratory of Molecular Biology, Addenbrooke' s Hospital Cambridge, CB2 0QH (United Kingdom); Domaschenz, Renae [MRC Cancer Cell Unit, Hutchison-MRC Research centre, Addenbrooke' s Hospital Cambridge, CB2 0XZ (United Kingdom); Gene Regulation and Chromatin Group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Campus, Du Cane Road, London W12 ONN (United Kingdom); Amagase, Yoko [MRC Cancer Cell Unit, Hutchison-MRC Research centre, Addenbrooke' s Hospital Cambridge, CB2 0XZ (United Kingdom); Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women' s College of Liberal Arts, Kodo, Kyotanabe, Kyoto 610-0395 (Japan); Williamson, Daniel [Molecular Cytogenetics, The Institute of Cancer Research, Sutton SM2 5NG (United Kingdom); Northern Institute for Cancer Research, Paul O' Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH (United Kingdom); Missiaglia, Edoardo; Shipley, Janet [Molecular Cytogenetics, The Institute of Cancer Research, Sutton SM2 5NG (United Kingdom); Murai, Kasumi [MRC Cancer Cell Unit, Hutchison-MRC Research centre, Addenbrooke' s Hospital Cambridge, CB2 0XZ (United Kingdom); Jones, Philip H, E-mail: phj20@cam.ac.uk [MRC Cancer Cell Unit, Hutchison-MRC Research centre, Addenbrooke' s Hospital Cambridge, CB2 0XZ (United Kingdom)

    2013-01-01

    Absract: HES6, a member of the hairy-enhancer-of-split family of transcription factors, plays multiple roles in myogenesis. It is a direct target of the myogenic transcription factor MyoD and has been shown to regulate the formation of the myotome in development, myoblast cell cycle exit and the organization of the actin cytoskeleton during terminal differentiation. Here we investigate the expression and function of HES6 in rhabdomyosarcoma, a soft tissue tumor which expresses myogenic genes but fails to differentiate into muscle. We show that HES6 is expressed at high levels in the subset of alveolar rhabdomyosarcomas expressing PAX/FOXO1 fusion genes (ARMSp). Knockdown of HES6 mRNA in the ARMSp cell line RH30 reduces proliferation and cell motility. This phenotype is rescued by expression of mouse Hes6 which is insensitive to HES6 siRNA. Furthermore, expression microarray analysis indicates that the HES6 knockdown is associated with a decrease in the levels of Transgelin, (TAGLN), a regulator of the actin cytoskeleton. Knockdown of TAGLN decreases cell motility, whilst TAGLN overexpression rescues the motility defect resulting from HES6 knockdown. These findings indicate HES6 contributes to the pathogenesis of ARMSp by enhancing both proliferation and cell motility.

  12. Alveolar epithelial type II cells induce T cell tolerance to specific antigen

    DEFF Research Database (Denmark)

    Lo, Bernice; Hansen, Søren; Evans, Kathy

    2008-01-01

    The lungs face the immunologic challenge of rapidly eliminating inhaled pathogens while maintaining tolerance to innocuous Ags. A break in this immune homeostasis may result in pulmonary inflammatory diseases, such as allergies or asthma. The observation that alveolar epithelial type II cells (Type...... II) constitutively express the class II MHC led us to hypothesize that Type II cells play a role in the adaptive immune response. Because Type II cells do not express detectable levels of the costimulatory molecules CD80 and CD86, we propose that Type II cells suppress activation of naive T cells...

  13. Transcriptomic profiling of primary alveolar epithelial cell differentiation in human and rat

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    Crystal N. Marconett

    2014-12-01

    Full Text Available Cell-type specific gene regulation is a key to gaining a full understanding of how the distinct phenotypes of differentiated cells are achieved and maintained. Here we examined how changes in transcriptional activation during alveolar epithelial cell (AEC differentiation determine phenotype. We performed transcriptomic profiling using in vitro differentiation of human and rat primary AEC. This model recapitulates in vitro an in vivo process in which AEC transition from alveolar type 2 (AT2 cells to alveolar type 1 (AT1 cells during normal maintenance and regeneration following lung injury. Here we describe in detail the quality control, preprocessing, and normalization of microarray data presented within the associated study (Marconett et al., 2013. We also include R code for reproducibility of the referenced data and easily accessible processed data tables.

  14. B Cell IgD Deletion Prevents Alveolar Bone Loss Following Murine Oral Infection

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    Pamela J. Baker

    2009-01-01

    and CD4+ T cells in immune normal mice compared to IgD deficient mice. These data suggest that IgD is an important mediator of alveolar bone resorption, possibly through antigen-specific coactivation of B cells and CD4+ T cells.

  15. Glucose-6-phosphate dehydrogenase in rat lung alveolar epithelial cells. An ultrastructural enzyme-cytochemical study

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    S Matsubara

    2010-01-01

    Full Text Available Glucose-6-phosphate dehydrogenase (G6PD is the key enzyme of the pentose phosphate pathway in carbohydrate metabolism, and it plays an important role in cell proliferation and antioxidant regulation within cells in various organs. Although marked cell proliferation and oxidant/antioxidant metabolism occur in lung alveolar epithelial cells, definite data has been lacking as to whether cytochemically detectable G6PD is present in alveolar epithelial cells. The distribution pattern of G6PD within these cells, if it is present, is also unknown. The purpose of the present study was to investigate the subcellular localization of G6PD in alveolar cells in the rat lung using a newly- developed enzyme-cytochemistry (copper-ferrocyanide method. Type I cells and stromal endothelia and fibroblasts showed no activities. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of type II alveolar epithelial cells. The cytochemical controls ensured specific detection of enzyme activity. This enzyme may play a role in airway defense by delivering substances for cell proliferation and antioxidant forces, thus maintaining the airway architecture.

  16. Stimulation of DNA synthesis in cultured rat alveolar type II cells

    International Nuclear Information System (INIS)

    Leslie, C.C.; McCormick-Shannon, K.; Robinson, P.C.; Mason, R.J.

    1985-01-01

    Restoration of the alveolar epithelium after injury is thought to be dependent on the proliferation of alveolar type II cells. To understand the factors that may be involved in promoting type II cell proliferation in vivo, we determined the effect of potential mitogens and culture substrata on DNA synthesis in rat alveolar type II cells in primary culture. Type II cells cultured in basal medium containing 10% fetal bovine serum (FBS) exhibited essentially no DNA synthesis. Factors that stimulated 3 H-thymidine incorporation included cholera toxin, epidermal growth factor, and rat serum. The greatest degree of stimulation was achieved by plating type II cells on an extracellular matrix prepared from bovine corneal endothelial cells and then by culturing the pneumocytes in medium containing rat serum, cholera toxin, insulin, and epidermal growth factor. Under conditions of stimulation of 3 H-thymidine incorporation there was an increased DNA content per culture dish but no increase in cell number. The ability of various culture conditions to promote DNA synthesis in type II cells was verified by autoradiography. Type II cells were identified by the presence of cytoplasmic inclusions, which were visualized by tannic acid staining before autoradiography. These results demonstrate the importance of soluble factors and culture substratum in stimulating DNA synthesis in rat alveolar type II cells in primary culture

  17. Alveolar Epithelial Cells in Mycobacterium tuberculosis Infection: Active Players or Innocent Bystanders?

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    Scordo, Julia M; Knoell, Daren L; Torrelles, Jordi B

    2016-01-01

    Tuberculosis (TB) is a disease that kills one person every 18 s. TB remains a global threat due to the emergence of drug-resistant Mycobacterium tuberculosis (M.tb) strains and the lack of an efficient vaccine. The ability of M.tb to persist in latency, evade recognition following seroconversion, and establish resistance in vulnerable populations warrants closer examination. Past and current research has primarily focused on examination of the role of alveolar macrophages and dendritic cells during M.tb infection, which are critical in the establishment of the host response during infection. However, emerging evidence indicates that the alveolar epithelium is a harbor for M.tb and critical during progression to active disease. Here we evaluate the relatively unexplored role of the alveolar epithelium as a reservoir and also its capacity to secrete soluble mediators upon M.tb exposure, which influence the extent of infection. We further discuss how the M.tb-alveolar epithelium interaction instigates cell-to-cell crosstalk that regulates the immune balance between a proinflammatory and an immunoregulatory state, thereby prohibiting or allowing the establishment of infection. We propose that consideration of alveolar epithelia provides a more comprehensive understanding of the lung environment in vivo in the context of host defense against M.tb. © 2015 S. Karger AG, Basel.

  18. Alveolar epithelial cells in Mycobacterium tuberculosis infection: Active Players or Innocent Bystanders

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    Scordo, Julia M.; Knoell, Daren L.; Torrelles, Jordi B.

    2015-01-01

    Tuberculosis (TB) is a disease that kills one person every 18 seconds. TB remains a global threat due to the emergence of drug resistance Mycobacterium tuberculosis (M.tb) strains and the lack of an efficient vaccine. The ability of M.tb to persist in latency, evade recognition following sero-conversion and establish resistance in vulnerable populations warrants closer examination. Past and current research has primarily focused on examination of the role of alveolar macrophages and dendritic cells during M.tb infection, which are critical in the establishment of the host response during infection. However, emerging evidence indicates that the alveolar epithelium is a harbor for M.tb and critical during progression to active disease. Here we evaluate the relatively unexplored role of the alveolar epithelium as a reservoir and also its capacity to secrete soluble mediators upon M.tb exposure that influence the extent of infection. We further discuss how the M.tb-alveolar epithelia interaction instigate cell to cell crosstalk that regulates immune balance between a pro-inflammatory or immunoregulatory state thereby prohibiting or allowing the establishment of infection. We propose that consideration of the alveolar epithelia provides a more comprehensive understanding of the lung environment in vivo in the context of host defense against M.tb. PMID:26384325

  19. Development of a lung slice preparation for recording ion channel activity in alveolar epithelial type I cells

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    Crandall Edward D

    2005-04-01

    Full Text Available Abstract Background Lung fluid balance in the healthy lung is dependent upon finely regulated vectorial transport of ions across the alveolar epithelium. Classically, the cellular locus of the major ion transport processes has been widely accepted to be the alveolar type II cell. Although evidence is now emerging to suggest that the alveolar type I cell might significantly contribute to the overall ion and fluid homeostasis of the lung, direct assessment of functional ion channels in type I cells has remained elusive. Methods Here we describe a development of a lung slice preparation that has allowed positive identification of alveolar type I cells within an intact and viable alveolar epithelium using living cell immunohistochemistry. Results This technique has allowed, for the first time, single ion channels of identified alveolar type I cells to be recorded using the cell-attached configuration of the patch-clamp technique. Conclusion This exciting new development should facilitate the ascription of function to alveolar type I cells and allow us to integrate this cell type into the general model of alveolar ion and fluid balance in health and disease.

  20. Inflammasome Inhibition Suppresses Alveolar Cell Permeability Through Retention of Neuregulin-1 (NRG-1

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    Rajanbabu Venugopal

    2015-07-01

    Full Text Available Background: Neuregulin (NRG-1-human epidermal receptor (HER-2 signaling pathway is a key regulator of IL-1β-mediated pulmonary inflammation and epithelial permeability. The inflammasome is a newly discovered molecular platform required for caspase-1 activation and maturation of IL-1β. However, the role of the inflammasome in NRG-1-HER2 signaling-mediated alveolar cell permeability is unknown. Methods: The inflammasome was activated or inhibited in THP-1 cells; supernatants from these cells were added to A549 cells and human small airway epithelial cells (HSAEC. The protein expression of NRG-1 and phospho-HER2 (pHER2 were measured by Western blot analysis and epithelial permeability was measured using Lucifer yellow dye. Results: Results reveal that alveolar permeability in A549 cells and HSAEC is increased when treated with supernatants of inflammasome-activated THP-1 cells. Alveolar permeability is significantly suppressed when treated with supernatant of inflammasome-inhibited THP-1 cells. Inflammasome-mediated permeability is decreased when A549 cells and HSAEC are pretreated with IL-1β receptor antagonist (IL-1βRA. In addition, HER2 kinase inhibitor AG825 or NRG-1 inhibitor TAPI inhibits inflammasome-mediated permeability in A549 cells and HSAEC demonstrating critical roles of IL-1β, NRG-1, and HER2 in inflammasome-mediated alveolar permeability. Conclusion: These findings suggest that inflammasome-induced alveolar cell permeability is mediated by NRG-1/HER2 signaling through IL-1β regulation.

  1. Cigarette Smoke Enhances the Expression of Profibrotic Molecules in Alveolar Epithelial Cells.

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    Marco Checa

    Full Text Available Idiopathic pulmonary fibrosis (IPF is a progressive and lethal disease of unknown etiology. A growing body of evidence indicates that it may result from an aberrant activation of alveolar epithelium, which induces the expansion of the fibroblast population, their differentiation to myofibroblasts and the excessive accumulation of extracellular matrix. The mechanisms that activate the alveolar epithelium are unknown, but several studies indicate that smoking is the main environmental risk factor for the development of IPF. In this study we explored the effect of cigarette smoke on the gene expression profile and signaling pathways in alveolar epithelial cells. Lung epithelial cell line from human (A549, was exposed to cigarette smoke extract (CSE for 1, 3, and 5 weeks at 1, 5 and 10% and gene expression was evaluated by complete transcriptome microarrays. Signaling networks were analyzed with the Ingenuity Pathway Analysis software. At 5 weeks of exposure, alveolar epithelial cells acquired a fibroblast-like phenotype. At this time, gene expression profile revealed a significant increase of more than 1000 genes and deregulation of canonical signaling pathways such as TGF-β and Wnt. Several profibrotic genes involved in EMT were over-expressed, and incomplete EMT was observed in these cells, and corroborated in mouse (MLE-12 and rat (RLE-6TN epithelial cells. The secretion of activated TGF-β1 increased in cells exposed to cigarette smoke, which decreased when the integrin alpha v gene was silenced. These findings suggest that the exposure of alveolar epithelial cells to CSE induces the expression and release of a variety of profibrotic genes, and the activation of TGF-β1, which may explain at least partially, the increased risk of developing IPF in smokers.

  2. Evidence for an intracellular niche for Bordetella pertussis in broncho-alveolar lavage cells of mice

    NARCIS (Netherlands)

    Hellwig, SMM; Hazenbos, WLW; van de Winkel, JGJ; Mooi, FR

    1999-01-01

    Bordetella pertussis can attach, invade and survive intracellularly in human macrophages in vitro. To study the significance of this bacterial feature in vivo, we analyzed the presence of viable bacteria in broncho-alveolar lavage (BAL) cells of mice infected with B, pertussis. We found B. pertussis

  3. Proteinase-activated receptor 4 stimulation-induced epithelial-mesenchymal transition in alveolar epithelial cells

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    Araki Hiromasa

    2007-04-01

    Full Text Available Abstract Background Proteinase-activated receptors (PARs; PAR1–4 that can be activated by serine proteinases such as thrombin and neutrophil catepsin G are known to contribute to the pathogenesis of various pulmonary diseases including fibrosis. Among these PARs, especially PAR4, a newly identified subtype, is highly expressed in the lung. Here, we examined whether PAR4 stimulation plays a role in the formation of fibrotic response in the lung, through alveolar epithelial-mesenchymal transition (EMT which contributes to the increase in myofibroblast population. Methods EMT was assessed by measuring the changes in each specific cell markers, E-cadherin for epithelial cell, α-smooth muscle actin (α-SMA for myofibroblast, using primary cultured mouse alveolar epithelial cells and human lung carcinoma-derived alveolar epithelial cell line (A549 cells. Results Stimulation of PAR with thrombin (1 U/ml or a synthetic PAR4 agonist peptide (AYPGKF-NH2, 100 μM for 72 h induced morphological changes from cobblestone-like structure to elongated shape in primary cultured alveolar epithelial cells and A549 cells. In immunocytochemical analyses of these cells, such PAR4 stimulation decreased E-cadherin-like immunoreactivity and increased α-SMA-like immunoreactivity, as observed with a typical EMT-inducer, tumor growth factor-β (TGF-β. Western blot analyses of PAR4-stimulated A549 cells also showed similar changes in expression of these EMT-related marker proteins. Such PAR4-mediated changes were attenuated by inhibitors of epidermal growth factor receptor (EGFR kinase and Src. PAR4-mediated morphological changes in primary cultured alveolar epithelial cells were reduced in the presence of these inhibitors. PAR4 stimulation increased tyrosine phosphorylated EGFR or tyrosine phosphorylated Src level in A549 cells, and the former response being inhibited by Src inhibitor. Conclusion PAR4 stimulation of alveolar epithelial cells induced epithelial

  4. Cultured alveolar epithelial cells from septic rats mimic in vivo septic lung.

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    Taylor S Cohen

    2010-06-01

    Full Text Available Sepsis results in the formation of pulmonary edema by increasing in epithelial permeability. Therefore we hypothesized that alveolar epithelial cells isolated from septic animals develop tight junctions with different protein composition and reduced barrier function relative to alveolar epithelial cells from healthy animals. Male rats (200-300 g were sacrificed 24 hours after cecal ligation and double puncture (2CLP or sham surgery. Alveolar epithelial cells were isolated and plated on fibronectin-coated flexible membranes or permeable, non-flexible transwell substrates. After a 5 day culture period, cells were either lysed for western analysis of tight junction protein expressin (claudin 3, 4, 5, 7, 8, and 18, occludin, ZO-1, and JAM-A and MAPk (JNK, ERK, an p38 signaling activation, or barrier function was examined by measuring transepithelial resistance (TER or the flux of two molecular tracers (5 and 20 A. Inhibitors of JNK (SP600125, 20 microM and ERK (U0126, 10 microM were used to determine the role of these pathways in sepsis induced epithelial barrier dysfunction. Expression of claudin 4, claudin 18, and occludin was significantly lower, and activation of JNK and ERK signaling pathways was significantly increased in 2CLP monolayers, relative to sham monolayers. Transepithelial resistance of the 2CLP monolayers was reduced significantly compared to sham (769 and 1234 ohm-cm(2, respectively, however no significant difference in the flux of either tracer was observed. Inhibition of ERK, not JNK, significantly increased TER and expression of claudin 4 in 2CLP monolayers, and prevented significant differences in claudin 18 expression between 2CLP and sham monolayers. We conclude that alveolar epithelial cells isolated from septic animals form confluent monolayers with impaired barrier function compared to healthy monolayers, and inhibition of ERK signaling partially reverses differences between these monolayers. This model provides a unique

  5. Dexmedetomidine Attenuates Oxidative Stress Induced Lung Alveolar Epithelial Cell Apoptosis In Vitro

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    Jian Cui

    2015-01-01

    Full Text Available Background. Oxidative stress plays a pivotal role in the lung injuries of critical ill patients. This study investigates the protection conferred by α2 adrenoceptor agonist dexmedetomidine (Dex from lung alveolar epithelial cell injury induced by hydrogen peroxide (H2O2 and the underlying mechanisms. Methods. The lung alveolar epithelial cell line, A549, was cultured and then treated with 500 μM H2O2 with or without Dex (1 nM or Dex in combination with atipamezole (10 nM, an antagonist of α2 receptors. Their effect on mitochondrial membrane potential (Δψm, reactive oxygen species (ROS, and the cell cycle was assessed by flow cytometry. Cleaved-caspases 3 and 9, BAX, Bcl-2, phospho-mTOR (p-mTOR, ERK1/2, and E-cadherin expression were also determined with immunocytochemistry. Results. Upregulation of cleaved-caspases 3 and 9 and BAX and downregulation of Bcl-2, p-mTOR, and E-cadherin were found following H2O2 treatment, and all of these were reversed by Dex. Dex also prevented the ROS generation, cytochrome C release, and cell cycle arrest induced by H2O2. The effects of Dex were partially reversed by atipamezole. Conclusion. Our study demonstrated that Dex protected lung alveolar epithelial cells from apoptotic injury, cell cycle arrest, and loss of cell adhesion induced by H2O2 through enhancing the cell survival and proliferation.

  6. When Is an Alveolar Type 2 Cell an Alveolar Type 2 Cell? A Conundrum for Lung Stem Cell Biology and Regenerative Medicine.

    Science.gov (United States)

    Beers, Michael F; Moodley, Yuben

    2017-07-01

    Generating mature, differentiated, adult lung cells from pluripotent cells, such as induced pluripotent stem cells and embryonic stem cells, offers the hope of both generating disease-specific in vitro models and creating definitive and personalized therapies for a host of debilitating lung parenchymal and airway diseases. With the goal of advancing lung-regenerative medicine, several groups have developed and reported on protocols using defined media, coculture with mesenchymal components, or sequential treatments mimicking lung development, to obtain distal lung epithelial cells from stem cell precursors. However, there remains significant controversy about the degree of differentiation of these cells compared with their primary counterparts, coupled with a lack of consistency or uniformity in assessing the resultant phenotypes. Given the inevitable, exponential expansion of these approaches and the probable, but yet-to-emerge second and higher generation techniques to create such assets, we were prompted to pose the question, what makes a lung epithelial cell a lung epithelial cell? More specifically for this Perspective, we also posed the question, what are the minimum features that constitute an alveolar type (AT) 2 epithelial cell? In addressing this, we summarize a body of work spanning nearly five decades, amassed by a series of "lung epithelial cell biology pioneers," which carefully describes well characterized molecular, functional, and morphological features critical for discriminately assessing an AT2 phenotype. Armed with this, we propose a series of core criteria to assist the field in confirming that cells obtained following a differentiation protocol are indeed mature and functional AT2 epithelial cells.

  7. Bronchoalveolar lavage fluid from normal rats stimulates DNA synthesis in rat alveolar type II cells

    International Nuclear Information System (INIS)

    Leslie, C.C.; McCormick-Shannon, K.; Mason, R.J.

    1989-01-01

    Proliferation of alveolar type II cells after lung injury is important for the restoration of the alveolar epithelium. Bronchoalveolar lavage fluid (BALF) may represent an important source of growth factors for alveolar type II cells. To test this possibility, BALF fluid was collected from normal rats, concentrated 10-fold by Amicon filtration, and tested for its ability to stimulate DNA synthesis in rat alveolar type II cells in primary culture. BALF induced a dose-dependent increase in type II cell DNA synthesis resulting in a 6-fold increase in [3H]thymidine incorporation. Similar doses also stimulated [3H]thymidine incorporation into rat lung fibroblasts by 6- to 8-fold. Removal of pulmonary surface active material by centrifugation did not significantly reduce the stimulatory activity of BALF for type II cells. The stimulation of type II cell DNA synthesis by BALF was reduced by 100% after heating at 100 degrees C for 10 min, and by approximately 80% after reduction with dithiothreitol, and after trypsin treatment. Dialysis of BALF against 1 N acetic acid resulted in a 27% reduction in stimulatory activity. The effect of BALF in promoting type II cell DNA synthesis was more pronounced when tested in the presence of serum, although serum itself has very little effect on type II cell DNA synthesis. When BALF was tested in combination with other substances that stimulate type II cell DNA synthesis (cholera toxin, insulin, epidermal growth factor, and acidic fibroblast growth factor), additive effects or greater were observed. When BALF was chromatographed over Sephadex G150, the activity eluted with an apparent molecular weight of 100 kDa

  8. Interfacial stress affects rat alveolar type II cell signaling and gene expression.

    Science.gov (United States)

    Hobi, Nina; Ravasio, Andrea; Haller, Thomas

    2012-07-01

    Previous work from our group (Ravasio A, Hobi N, Bertocchi C, Jesacher A, Dietl P, Haller T. Am J Physiol Cell Physiol 300: C1456-C1465, 2011.) showed that contact of alveolar epithelial type II cells with an air-liquid interface (I(AL)) leads to a paradoxical situation. It is a potential threat that can cause cell injury, but also a Ca(2+)-dependent stimulus for surfactant secretion. Both events can be explained by the impact of interfacial tensile forces on cellular structures. Here, the strength of this mechanical stimulus became also apparent in microarray studies by a rapid and significant change on the transcriptional level. Cells challenged with an I(AL) in two different ways showed activation/inactivation of cellular pathways involved in stress response and defense, and a detailed Pubmatrix search identified genes associated with several lung diseases and injuries. Altogether, they suggest a close relationship of interfacial stress sensation with current models in alveolar micromechanics. Further similarities between I(AL) and cell stretch were found with respect to the underlying signaling events. The source of Ca(2+) was extracellular, and the transmembrane Ca(2+) entry pathway suggests the involvement of a mechanosensitive channel. We conclude that alveolar type II cells, due to their location and morphology, are specific sensors of the I(AL), but largely protected from interfacial stress by surfactant release.

  9. Dichloroacetate Decreases Cell Health and Activates Oxidative Stress Defense Pathways in Rat Alveolar Type II Pneumocytes

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    Alexis Valauri-Orton

    2015-01-01

    Full Text Available Dichloroacetate (DCA is a water purification byproduct that is known to be hepatotoxic and hepatocarcinogenic and to induce peripheral neuropathy and damage macrophages. This study characterizes the effects of the haloacetate on lung cells by exposing rat alveolar type II (L2 cells to 0–24 mM DCA for 6–24 hours. Increasing DCA concentration and the combination of increasing DCA concentration plus longer exposures decrease measures of cellular health. Length of exposure has no effect on oxidative stress biomarkers, glutathione, SOD, or CAT. Increasing DCA concentration alone does not affect total glutathione or its redox ratio but does increase activity in the SOD/CAT oxidative stress defense pathway. These data suggest that alveolar type II cells rely on SOD and CAT more than glutathione to combat DCA-induced stress.

  10. Influenza H5N1 virus infection of polarized human alveolar epithelial cells and lung microvascular endothelial cells

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    Yuen Kit M

    2009-10-01

    Full Text Available Abstract Background Highly pathogenic avian influenza (HPAI H5N1 virus is entrenched in poultry in Asia and Africa and continues to infect humans zoonotically causing acute respiratory disease syndrome and death. There is evidence that the virus may sometimes spread beyond respiratory tract to cause disseminated infection. The primary target cell for HPAI H5N1 virus in human lung is the alveolar epithelial cell. Alveolar epithelium and its adjacent lung microvascular endothelium form host barriers to the initiation of infection and dissemination of influenza H5N1 infection in humans. These are polarized cells and the polarity of influenza virus entry and egress as well as the secretion of cytokines and chemokines from the virus infected cells are likely to be central to the pathogenesis of human H5N1 disease. Aim To study influenza A (H5N1 virus replication and host innate immune responses in polarized primary human alveolar epithelial cells and lung microvascular endothelial cells and its relevance to the pathogenesis of human H5N1 disease. Methods We use an in vitro model of polarized primary human alveolar epithelial cells and lung microvascular endothelial cells grown in transwell culture inserts to compare infection with influenza A subtype H1N1 and H5N1 viruses via the apical or basolateral surfaces. Results We demonstrate that both influenza H1N1 and H5N1 viruses efficiently infect alveolar epithelial cells from both apical and basolateral surface of the epithelium but release of newly formed virus is mainly from the apical side of the epithelium. In contrast, influenza H5N1 virus, but not H1N1 virus, efficiently infected polarized microvascular endothelial cells from both apical and basolateral aspects. This provides a mechanistic explanation for how H5N1 virus may infect the lung from systemic circulation. Epidemiological evidence has implicated ingestion of virus-contaminated foods as the source of infection in some instances and our

  11. Expression of functional toll-like receptor-2 and -4 on alveolar epithelial cells.

    Science.gov (United States)

    Armstrong, Lynne; Medford, Andrew R L; Uppington, Kay M; Robertson, John; Witherden, Ian R; Tetley, Teresa D; Millar, Ann B

    2004-08-01

    The recognition of potentially harmful microorganisms involves the specific recognition of pathogen-associated molecular patterns (PAMPs) and the family of Toll-like receptors (TLRs) is known to play a central role in this process. TLR-4 is the major recognition receptor for lipopolysaccharide (LPS), a component of gram-negative bacterial cell walls, whereas TLR-2 responds to bacterial products from gram-positive organisms. Although resident alveolar macrophages are the first line of defense against microbial attack, it is now understood that the alveolar epithelium also plays a pivotal role in the innate immunity of the lung. The purpose of the current study was to determine whether human primary type II alveolar epithelial cells (ATII) express functional TLR-2 and TLR-4 and how they may be regulated by inflammatory mediators. We have used reverse transcriptase-polymerase chain reaction and flow cytometry to determine basal and inducible expression on ATII. We have used highly purified preparations of the gram-positive bacterial product lipoteichoic acid (LTA) and LPS to look at the functional consequences of TLR-2 and TLR-4 ligation, respectively, in terms of interleukin-8 release. We have shown that human primary ATII cells express mRNA and protein for both TLR-2 and TLR-4, which can be modulated by incubation with LPS and tumor necrosis factor. Furthermore, we have demonstrated that these receptors are functional. This suggests that ATII have the potential to contribute significantly to the host defense of the human alveolus against bacteria.

  12. Glutathione synthesis and homeostasis in isolated type II alveolar cells

    International Nuclear Information System (INIS)

    Saito, K.; Warshaw, J.B.; Prough, R.A.

    1986-01-01

    After isolation of Type II cells from neonatal rat lung, the glutathione (GSH) levels in these cells were greatly depressed. The total glutathione content could be increased 5-fold within 12-24 h by incubating the cells in media containing sulfur amino acids. Similarly, the activity of γ-glutamyltranspeptidase was low immediately after isolation, but was increased 2-fold during the first 24 h culture. Addition of either GSH or GSSG to the culture media increased the GSH content of Type II cells 2-2.5-fold. Buthionine sulfoximine and NaF prevented this replenishment of GSH during 24 h culture. When the rates of de novo synthesis of GSH and GSSG from 35 S-cysteine were measured, the amounts of newly formed GSH decreased to 80% in the presence of GSH or GSSG. This suggests that exogenous GSH/GSSG can be taken up by the Type II cells to replenish the intracellular pool of GSH. Methionine was not as effective as cysteine in the synthesis of GSH. These results suggest that GSH levels in the isolated Type II cell can be maintained by de novo synthesis or uptake of exogenous GSH. Most of the GSH synthesized from cysteine, however, was excreted into the media of the cultured cells indicative of a potential role for the type II cell in export of the non-protein thiol

  13. Interfacial stress affects rat alveolar type II cell signaling and gene expression

    OpenAIRE

    Hobi, Nina; Ravasio, Andrea; Haller, Thomas

    2012-01-01

    Previous work from our group (Ravasio A, Hobi N, Bertocchi C, Jesacher A, Dietl P, Haller T. Am J Physiol Cell Physiol 300: C1456–C1465, 2011.) showed that contact of alveolar epithelial type II cells with an air-liquid interface (IAL) leads to a paradoxical situation. It is a potential threat that can cause cell injury, but also a Ca2+-dependent stimulus for surfactant secretion. Both events can be explained by the impact of interfacial tensile forces on cellular structures. Here, the streng...

  14. Establishment and evaluation of a stable cattle type II alveolar epithelial cell line.

    Directory of Open Access Journals (Sweden)

    Feng Su

    Full Text Available Macrophages and dendritic cells are recognized as key players in the defense against mycobacterial infection. Recent research has confirmed that alveolar epithelial cells (AECs also play important roles against mycobacterium infections. Thus, establishing a stable cattle AEC line for future endogenous immune research on bacterial invasion is necessary. In the present study, we first purified and immortalized type II AECs (AEC II cells by transfecting them with a plasmid containing the human telomerase reverse trancriptase gene. We then tested whether or not the immortalized cells retained the basic physiological properties of primary AECs by reverse-transcription polymerase chain reaction and Western blot. Finally, we tested the secretion capacity of immortalized AEC II cells upon stimulation by bacterial invasion. The cattle type II alveolar epithelial cell line (HTERT-AEC II that we established retained lung epithelial cell characteristics: the cells were positive for surfactants A and B, and they secreted tumor necrosis factor-α and interleukin-6 in response to bacterial invasion. Thus, the cell line we established is a potential tool for research on the relationship between AECs and Mycobacterium tuberculosis.

  15. Ghrelin ameliorates the human alveolar epithelial A549 cell apoptosis induced by lipopolysaccharide

    International Nuclear Information System (INIS)

    Huang, Chunrong; Zheng, Haichong; He, Wanmei; Lu, Guifang; Li, Xia; Deng, Yubin; Zeng, Mian

    2016-01-01

    Ghrelin is a gastric acyl-peptide that plays an inhibitory role in cell apoptosis. Herein we investigate the protective effects of ghrelin in LPS-induced apoptosis of human alveolar epithelial A549 cells, along with the possible molecular mechanisms. LPS exposure impaired cell viability and increased apoptosis of A549 cells significantly in concentration- and time-dependent manners embodied in increased Bax and cleaved caspase-3 production, coupled with decreased Bcl-2 levels. Simultaneously, LPS remarkably decreased the expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinas (ERK) in A549 cells. However, ghrelin'pretreatment ameliorated LPS-caused alterations in the ratio of Bax/Bcl-2 and cleaved caspase-3 expression, whereas activated the PI3K/Akt and ERK signaling. These results demonstrate that ghrelin lightens LPS-induced apoptosis of human alveolar epithelial cells partly through activating the PI3K/Akt and ERK pathway and thereby might benefit alleviating septic ALI. -- Graphical abstract: Ghrelin ameliorates the human alveolar epithelial A549 cells apoptosis induced by lipopolysaccharide partly through activating the PI3K/Akt and ERK pathway. Display Omitted -- Highlights: •It has been observed that LPS insult significantly increased apoptosis in A549 cells. •Both Akt and ERK signaling are critical adapter molecules to mediate the ghrelin-mediated proliferative effect. •Ghrelin may have a therapeutic effect in the prevention of LPS-induced apoptosis.

  16. Ghrelin ameliorates the human alveolar epithelial A549 cell apoptosis induced by lipopolysaccharide

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chunrong; Zheng, Haichong; He, Wanmei; Lu, Guifang; Li, Xia [Department of Medical Intensive Care Unit, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080 (China); Deng, Yubin, E-mail: dengyub@mail.sysu.edu.cn [Research Center of Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080 (China); Zeng, Mian, E-mail: zengmian2004@163.com [Department of Medical Intensive Care Unit, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080 (China)

    2016-05-20

    Ghrelin is a gastric acyl-peptide that plays an inhibitory role in cell apoptosis. Herein we investigate the protective effects of ghrelin in LPS-induced apoptosis of human alveolar epithelial A549 cells, along with the possible molecular mechanisms. LPS exposure impaired cell viability and increased apoptosis of A549 cells significantly in concentration- and time-dependent manners embodied in increased Bax and cleaved caspase-3 production, coupled with decreased Bcl-2 levels. Simultaneously, LPS remarkably decreased the expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinas (ERK) in A549 cells. However, ghrelin'pretreatment ameliorated LPS-caused alterations in the ratio of Bax/Bcl-2 and cleaved caspase-3 expression, whereas activated the PI3K/Akt and ERK signaling. These results demonstrate that ghrelin lightens LPS-induced apoptosis of human alveolar epithelial cells partly through activating the PI3K/Akt and ERK pathway and thereby might benefit alleviating septic ALI. -- Graphical abstract: Ghrelin ameliorates the human alveolar epithelial A549 cells apoptosis induced by lipopolysaccharide partly through activating the PI3K/Akt and ERK pathway. Display Omitted -- Highlights: •It has been observed that LPS insult significantly increased apoptosis in A549 cells. •Both Akt and ERK signaling are critical adapter molecules to mediate the ghrelin-mediated proliferative effect. •Ghrelin may have a therapeutic effect in the prevention of LPS-induced apoptosis.

  17. Regeneration of alveolar type I and II cells from Scgb1a1-expressing cells following severe pulmonary damage induced by bleomycin and influenza.

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    Dahai Zheng

    Full Text Available The lung comprises an extensive surface of epithelia constantly exposed to environmental insults. Maintaining the integrity of the alveolar epithelia is critical for lung function and gaseous exchange. However, following severe pulmonary damage, what progenitor cells give rise to alveolar type I and II cells during the regeneration of alveolar epithelia has not been fully determined. In this study, we have investigated this issue by using transgenic mice in which Scgb1a1-expressing cells and their progeny can be genetically labeled with EGFP. We show that following severe alveolar damage induced either by bleomycin or by infection with influenza virus, the majority of the newly generated alveolar type II cells in the damaged parenchyma were labeled with EGFP. A large proportion of EGFP-expressing type I cells were also observed among the type II cells. These findings strongly suggest that Scgb1a1-expressing cells, most likely Clara cells, are a major cell type that gives rise to alveolar type I and II cells during the regeneration of alveolar epithelia in response to severe pulmonary damage in mice.

  18. Mycobacterium tuberculosis infection causes different levels of apoptosis and necrosis in human macrophages and alveolar epithelial cells.

    Science.gov (United States)

    Danelishvili, Lia; McGarvey, Jeffery; Li, Yong-Jun; Bermudez, Luiz E

    2003-09-01

    Mycobacterium tuberculosis interacts with macrophages and epithelial cells in the alveolar space of the lung, where it is able to invade and replicate in both cell types. M. tuberculosis-associated cytotoxicity to these cells has been well documented, but the mechanisms of host cell death are not well understood. We examined the induction of apoptosis and necrosis of human macrophages (U937) and type II alveolar epithelial cells (A549) by virulent (H37Rv) and attenuated (H37Ra) M. tuberculosis strains. Apoptosis was determined by both enzyme-linked immunosorbent assay (ELISA) and TdT-mediated dUTP nick end labelling (TUNEL) assay, whereas necrosis was evaluated by the release of lactate dehydrogenase (LDH). Both virulent and attenuated M. tuberculosis induced apoptosis in macrophages; however, the attenuated strain resulted in significantly more apoptosis than the virulent strain after 5 days of infection. In contrast, cytotoxicity of alveolar cells was the result of necrosis, but not apoptosis. Although infection with M. tuberculosis strains resulted in apoptosis of 14% of the cells on the monolayer, cell death associated with necrosis was observed in 59% of alveolar epithelial cells after 5 days of infection. Infection with M. tuberculosis suppressed apoptosis of alveolar epithelial cells induced by the kinase inhibitor, staurosporine. Because our findings suggest that M. tuberculosis can modulate the apoptotic response of macrophages and epithelial cells, we carried out an apoptosis pathway-specific cDNA microarray analysis of human macrophages and alveolar epithelial cells. Whereas the inhibitors of apoptosis, bcl-2 and Rb, were upregulated over 2.5-fold in infected (48 h) alveolar epithelial cells, the proapoptotic genes, bad and bax, were downregulated. The opposite was observed when U937 macrophages were infected with M. tuberculosis. Upon infection of alveolar epithelial cells with M. tuberculosis, the generation of apoptosis, as determined by the

  19. Arachidonate metabolism increases as rat alveolar type II cells differentiate in vitro

    International Nuclear Information System (INIS)

    Lipchik, R.J.; Chauncey, J.B.; Paine, R.; Simon, R.H.; Peters-Golden, M.

    1990-01-01

    Rat type II alveolar epithelial cells are known to undergo morphological and functional changes when maintained in culture for several days. Having previously demonstrated that these cells can deacylate free arachidonic acid (AA) and metabolize it to products of the cyclooxygenase pathway, the present study was undertaken to determine whether in vitro differentiation was accompanied by alterations in the availability and metabolism of AA. We assessed the constitutive and ionophore A23187-induced deacylation and metabolism of endogenous AA, as well as the metabolism of exogenously supplied AA, in primary cultures of rat type II cells at days 2, 4, and 7 after isolation. Levels of free endogenous AA were increased at day 4, whereas eicosanoid synthesis, predominantly prostaglandin E2 and prostacyclin, increased markedly only at day 7. A similar time course of augmentation of prostanoid release was seen in response to exogenous AA. Type II cells cultured on fibronectin, intended to hasten cell flattening and spreading, demonstrated accelerated increases in available free AA in response to A23187; cells cultured on basement membrane derived from Engelbreth-Holm-Swarm mouse sarcoma, known to maintain the type II phenotype, exhibited diminished levels of available free AA. From these findings, we conclude that alterations in arachidonate metabolism are linked to alterations in cellular phenotype. The potentiation of eicosanoid synthesis accompanying in vitro differentiation suggests a possible role for the alveolar epithelium in the modulation of inflammation and fibrosis in the distal lung

  20. Evidence for the involvement of cofilin in Aspergillus fumigatus internalization into type II alveolar epithelial cells.

    Science.gov (United States)

    Bao, Zhiyao; Han, Xuelin; Chen, Fangyan; Jia, Xiaodong; Zhao, Jingya; Zhang, Changjian; Yong, Chen; Tian, Shuguang; Zhou, Xin; Han, Li

    2015-08-13

    The internalization of Aspergillus fumigatus into alveolar epithelial cells (AECs) is tightly controlled by host cellular actin dynamics, which require close modulation of the ADF (actin depolymerizing factor)/cofilin family. However, the role of cofilin in A. fumigatus internalization into AECs remains unclear. Here, we demonstrated that germinated A. fumigatus conidia were able to induce phosphorylation of cofilin in A549 cells during the early stage of internalization. The modulation of cofilin activity by overexpression, knockdown, or mutation of the cofilin gene in A549 cells decreased the efficacy of A. fumigatus internalization. Reducing the phosphorylation status of cofilin with BMS-5 (LIM kinase inhibitor) or overexpression of the slingshot phosphatases also impeded A. fumigatus internalization. Both the C. botulimun C3 transferase (a specific RhoA inhibitor) and Y27632 (a specific ROCK inhibitor) reduced the internalization of A. fumigatus and the level of phosphorylated cofilin. β-1,3-glucan (the major component of the conidial cell wall) and its host cell receptor dectin-1 did not seem to be associated with cofilin phosphorylation during A. fumigatus infection. These results indicated that cofilin might be involved in the modulation of A. fumigatus internalization into type II alveolar epithelial cells through the RhoA-ROCK-LIM kinase pathway.

  1. Decreased CXCL12 is associated with impaired alveolar epithelial cell migration and poor lung healing after lung resection.

    Science.gov (United States)

    Kanter, Jacob A; Sun, Haiying; Chiu, Stephen; DeCamp, Malcolm M; Sporn, Peter H S; Sznajder, Jacob I; Bharat, Ankit

    2015-10-01

    Prolonged air leak (PAL) is an important cause of morbidity and mortality after lung resection, but its pathogenesis has not been elucidated. Migration of alveolar type II epithelial cells is essential for lung wound repair. Here we determined the role of C-X-C motif chemokine 12 (CXCL12) on alveolar epithelial cell migration and lung wound healing. CXCL12 in the pleural fluid of patients was analyzed using enzyme-linked immunosorbent assay. Human A549 and murine MLE12 alveolar epithelial cell lines were used for wound closure, cell migration, and proliferation assays. Western blot was used to analyze Rac1 and cofilin. Pleural CXCL12 was decreased in patients with PAL (1,389 ± 192 vs 3,270 ± 247 pg/mL; P alveolar epithelial cell migration by binding to its receptor CXCR4 and may have a role in lung healing. CXCL12-mediated alveolar epithelial cell migration is associated with Rac1 and cofilin activation. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Deletion of SMARCA4 impairs alveolar epithelial type II cells proliferation and aggravates pulmonary fibrosis in mice

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    Danyi Peng

    2017-12-01

    Full Text Available Alveolar epithelial cells (AECs injury and failed reconstitution of the AECs barrier are both integral to alveolar flooding and subsequent pulmonary fibrosis (PF. Nevertheless, the exact mechanisms regulating the regeneration of AECs post-injury still remain unclear. SMARCA4 is a part of the large ATP-dependent chromatin remodelling complex SWI/SNF, which is essential for kidney and heart fibrosis. We investigates SMARCA4 function in lung fibrosis by establishing PF mice model with bleomycin firstly and found that the expression of SMARCA4 was mainly enhanced in alveolar type II (ATII cells. Moreover, we established an alveolar epithelium-specific SMARCA4-deleted SP-C-rtTA/(tetO7-Cre/SMARCA4f/f mice (SOSM4Δ/Δ model, as well as a new SMARCA4-deleted alveolar type II (ATII-like mle-12 cell line. We found that the bleomycin-induced PF was more aggressive in SOSM4Δ/Δ mice. Also, the proliferation of ATII cells was decreased with the loss of SMARCA4 in vivo and in vitro. In addition, we observed increased proliferation of ATII cells accompanied by abnormally high expression of SMARCA4 in human PF lung sections. These data uncovered the indispensable role of SMARCA4 in the proliferation of ATII cells, which might affect the progression of PF.

  3. Protein Expression Profile of Rat Type Two Alveolar Epithelial Cells During Hyperoxic Stress and Recovery

    Science.gov (United States)

    Bhargava, Maneesh

    Rationale: In rodent model systems, the sequential changes in lung morphology resulting from hyperoxic injury are well characterized, and are similar to changes in human acute respiratory distress syndrome (ARDS). In the injured lung, alveolar type two (AT2) epithelial cells play a critical role restoring the normal alveolar structure. Thus characterizing the changes in AT2 cells will provide insights into the mechanisms underpinning the recovery from lung injury. Methods: We applied an unbiased systems level proteomics approach to elucidate molecular mechanisms contributing to lung repair in a rat hyperoxic lung injury model. AT2 cells were isolated from rat lungs at predetermined intervals during hyperoxic injury and recovery. Protein expression profiles were determined by using iTRAQRTM with tandem mass spectrometry. Results: Of 959 distinct proteins identified, 183 significantly changed in abundance during the injury-recovery cycle. Gene Ontology enrichment analysis identified cell cycle, cell differentiation, cell metabolism, ion homeostasis, programmed cell death, ubiquitination, and cell migration to be significantly enriched by these proteins. Gene Set Enrichment Analysis of data acquired during lung repair revealed differential expression of gene sets that control multicellular organismal development, systems development, organ development, and chemical homeostasis. More detailed analysis identified activity in two regulatory pathways, JNK and miR 374. A Short Time-series Expression Miner (STEM) algorithm identified protein clusters with coherent changes during injury and repair. Conclusion: Coherent changes occur in the AT2 cell proteome in response to hyperoxic stress. These findings offer guidance regarding the specific molecular mechanisms governing repair of the injured lung.

  4. Alveolar architecture of clear cell renal carcinomas (≤5.0 cm) show high attenuation on dynamic CT scanning

    International Nuclear Information System (INIS)

    Fujimoto, Hiroyuki; Wakao, Fumihiko; Moriyama, Noriyuki; Tobisu, Kenichi; Kakizoe, Tadao; Sakamoto, Michiie

    1999-01-01

    To establish the correlation between tumor appearance on CT and tumor histology in renal cell carcinomas. The density and attenuation patterns of 96 renal cell carcinomas, each ≤5 cm in greatest diameter, were studied by non-enhanced CT and early and late after bolus injection of contrast medium using dynamic CT. The density and attenuation patterns and pathological maps of each tumor were individually correlated. High attenuated areas were present in 72 of the 96 tumors on early enhanced dynamic CT scanning. All 72 high attenuated areas were of the clear cell renal cell carcinoma and had alveolar architecture. The remaining 24 tumors that did not demonstrate high attenuated foci on early enhanced scanning included three clear cell, nine granular cell, six papillary, five chromophobe and one collecting duct type. With respect to tumor architecture, all clear cell tumors of alveolar architecture demonstrated high attenuation on early enhanced scanning. Clear cell renal cell carcinomas of alveolar architecture show high attenuation on early enhanced dynamic CT scanning. A larger number of patients are indispensable to obtaining clear results. However, these findings seem to be an important clue to the diagnosis of renal cell carcinomas as having an alveolar structure. (author)

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

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    Sun-Kyoung Im

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

  6. Receptor for advanced glycation end-products is a marker of type I lung alveolar cells.

    Science.gov (United States)

    Shirasawa, Madoka; Fujiwara, Naoyuki; Hirabayashi, Susumu; Ohno, Hideki; Iida, Junko; Makita, Koshi; Hata, Yutaka

    2004-02-01

    Lung alveolar epithelial cells are comprised of type I (ATI) and type II (ATII) cells. ATI cells are polarized, although they have very flat morphology. The identification of marker proteins for apical and basolateral membranes of ATI cells is important to investigate into the differentiation of ATI cells. In this paper, we characterized receptor for advanced glycation end-products (RAGE) as a marker for ATI cells. RAGE was localized on basolateral membranes of ATI cells in the immunoelectron microscopy and its expression was enhanced in a parallel manner to the differentiation of ATI cells in vivo and in primary cultures of ATII cells. RAGE and T1 alpha, a well-known ATI marker protein, were targeted to basolateral and apical membranes, respectively, when expressed in polarized Madine Darby canine kidney cells. Moreover, RAGE was expressed in ATI cells after T1 alpha in vivo and in ex in vivo organ cultures. In conclusion, RAGE is a marker for basolateral membranes of well-differentiated ATI cells. ATI cells require some signal provided by the in vivo environment to express RAGE.

  7. Silencing hyperoxia-induced C/EBPα in neonatal mice improves lung architecture via enhanced proliferation of alveolar epithelial cells

    Science.gov (United States)

    Yang, Guang; Hinson, Maurice D.; Bordner, Jessica E.; Lin, Qing S.; Fernando, Amal P.; La, Ping; Wright, Clyde J.

    2011-01-01

    Postnatal lung development requires proliferation and differentiation of specific cell types at precise times to promote proper alveolar formation. Hyperoxic exposure can disrupt alveolarization by inhibiting cell growth; however, it is not fully understood how this is mediated. The transcription factor CCAAT/enhancer binding protein-α (C/EBPα) is highly expressed in the lung and plays a role in cell proliferation and differentiation in many tissues. After 72 h of hyperoxia, C/EBPα expression was significantly enhanced in the lungs of newborn mice. The increased C/EBPα protein was predominantly located in alveolar type II cells. Silencing of C/EBPα with a transpulmonary injection of C/EBPα small interfering RNA (siRNA) prior to hyperoxic exposure reduced expression of markers of type I cell and differentiation typically observed after hyperoxia but did not rescue the altered lung morphology at 72 h. Nevertheless, when C/EBPα hyperoxia-exposed siRNA-injected mice were allowed to recover for 2 wk in room air, lung epithelial cell proliferation was increased and lung morphology was restored compared with hyperoxia-exposed control siRNA-injected mice. These data suggest that C/EBPα is an important regulator of postnatal alveolar epithelial cell proliferation and differentiation during injury and repair. PMID:21571903

  8. Spatiotemporal dynamics of actin remodeling and endomembrane trafficking in alveolar epithelial type I cell wound healing.

    Science.gov (United States)

    Godin, Lindsay M; Vergen, Jorge; Prakash, Y S; Pagano, Richard E; Hubmayr, Rolf D

    2011-04-01

    Alveolar epithelial type I cell (ATI) wounding is prevalent in ventilator-injured lungs and likely contributes to pathogenesis of "barotrauma" and "biotrauma." In experimental models most wounded alveolar cells repair plasma membrane (PM) defects and survive insults. Considering the force balance between edge energy at the PM wound margins and adhesive interactions of the lipid bilayer with the underlying cytoskeleton (CSK), we tested the hypothesis that subcortical actin depolymerization is a key facilitator of PM repair. Using real-time fluorescence imaging of primary rat ATI transfected with a live cell actin-green fluorescent protein construct (Lifeact-GFP) and loaded with N-rhodamine phosphatidylethanolamine (PE), we examined the spatial and temporal coordination between cytoskeletal remodeling and PM repair following micropuncture. Membrane integrity was inferred from the fluorescence intensity profiles of the cytosolic label calcein AM. Wounding led to rapid depolymerization of the actin CSK near the wound site, concurrent with accumulation of endomembrane-derived N-rhodamine PE. Both responses were sustained until PM integrity was reestablished, which typically occurs between ∼10 and 40 s after micropuncture. Only thereafter did the actin CSK near the wound begin to repolymerize, while the rate of endomembrane lipid accumulation decreased. Between 60 and 90 s after successful PM repair, after translocation of the actin nucleation factor cortactin, a dense actin fiber network formed. In cells that did not survive micropuncture injury, actin remodeling did not occur. These novel results highlight the importance of actin remodeling in ATI cell repair and suggest molecular targets for modulating the repair process.

  9. Lung fibroblasts accelerate wound closure in human alveolar epithelial cells through hepatocyte growth factor/c-Met signaling.

    Science.gov (United States)

    Ito, Yoko; Correll, Kelly; Schiel, John A; Finigan, Jay H; Prekeris, Rytis; Mason, Robert J

    2014-07-01

    There are 190,600 cases of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) each year in the United States, and the incidence and mortality of ALI/ARDS increase dramatically with age. Patients with ALI/ARDS have alveolar epithelial injury, which may be worsened by high-pressure mechanical ventilation. Alveolar type II (ATII) cells are the progenitor cells for the alveolar epithelium and are required to reestablish the alveolar epithelium during the recovery process from ALI/ARDS. Lung fibroblasts (FBs) migrate and proliferate early after lung injury and likely are an important source of growth factors for epithelial repair. However, how lung FBs affect epithelial wound healing in the human adult lung has not been investigated in detail. Hepatocyte growth factor (HGF) is known to be released mainly from FBs and to stimulate both migration and proliferation of primary rat ATII cells. HGF is also increased in lung tissue, bronchoalveolar lavage fluid, and serum in patients with ALI/ARDS. Therefore, we hypothesized that HGF secreted by FBs would enhance wound closure in alveolar epithelial cells (AECs). Wound closure was measured using a scratch wound-healing assay in primary human AEC monolayers and in a coculture system with FBs. We found that wound closure was accelerated by FBs mainly through HGF/c-Met signaling. HGF also restored impaired wound healing in AECs from the elderly subjects and after exposure to cyclic stretch. We conclude that HGF is the critical factor released from FBs to close wounds in human AEC monolayers and suggest that HGF is a potential strategy for hastening alveolar repair in patients with ALI/ARDS. Copyright © 2014 the American Physiological Society.

  10. Gene expression patterns induced at different stages of rhinovirus infection in human alveolar epithelial cells.

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    Mohammad Reza Etemadi

    Full Text Available Human rhinovirus (HRV is the common virus that causes acute respiratory infection (ARI and is frequently associated with lower respiratory tract infections (LRTIs. We aimed to investigate whether HRV infection induces a specific gene expression pattern in airway epithelial cells. Alveolar epithelial cell monolayers were infected with HRV species B (HRV-B. RNA was extracted from both supernatants and infected monolayer cells at 6, 12, 24 and 48 hours post infection (hpi and transcriptional profile was analyzed using Affymetrix GeneChip and the results were subsequently validated using quantitative Real-time PCR method. HRV-B infects alveolar epithelial cells which supports implication of the virus with LRTIs. In total 991 genes were found differentially expressed during the course of infection. Of these, 459 genes were up-regulated whereas 532 genes were down-regulated. Differential gene expression at 6 hpi (187 genes up-regulated vs. 156 down-regulated were significantly represented by gene ontologies related to the chemokines and inflammatory molecules indicating characteristic of viral infection. The 75 up-regulated genes surpassed the down-regulated genes (35 at 12 hpi and their enriched ontologies fell into discrete functional entities such as regulation of apoptosis, anti-apoptosis, and wound healing. At later time points of 24 and 48 hpi, predominated down-regulated genes were enriched for extracellular matrix proteins and airway remodeling events. Our data provides a comprehensive image of host response to HRV infection. The study suggests the underlying molecular regulatory networks genes which might be involved in pathogenicity of the HRV-B and potential targets for further validations and development of effective treatment.

  11. Vitamin E alters alveolar type II cell phospholipid synthesis in oxygen and air

    International Nuclear Information System (INIS)

    Kennedy, K.A.; Snyder, J.M.; Stenzel, W.; Saito, K.; Warshaw, J.B.

    1990-01-01

    Newborn rats were injected with vitamin E or placebo daily until 6 days after birth. The effect of vitamin E pretreatment on in vitro surfactant phospholipid synthesis was examined in isolated type II cells exposed to oxygen or air form 24 h in vitro. Type II cells were also isolated from untreated 6-day-old rats and cultured for 24 h in oxygen or air with control medium or vitamin E supplemented medium. These cells were used to examine the effect of vitamin E exposure in vitro on type II cell phospholipid synthesis and ultrastructure. Phosphatidylcholine (PC) synthesis was reduced in cells cultured in oxygen as compared with air. This decrease was not prevented by in vivo pretreatment or in vitro supplementation with vitamin E. Vitamin E pretreatment increased the ratio of disaturated PC to total PC and increased phosphatidylglycerol synthesis. The volume density of lamellar bodies in type II cells was increased in cells maintained in oxygen. Vitamin E did not affect the volume density of lamellar bodies. We conclude that in vitro hyperoxia inhibits alveolar type II cell phosphatidylcholine synthesis without decreasing lamellar body volume density and that supplemental vitamin E does not prevent hyperoxia-induced decrease in phosphatidylcholine synthesis

  12. Emodin suppresses TGF-β1-induced epithelial-mesenchymal transition in alveolar epithelial cells through Notch signaling pathway

    International Nuclear Information System (INIS)

    Gao, Rundi; Chen, Ruilin; Cao, Yu; Wang, Yuan; Song, Kang; Zhang, Ya; Yang, Junchao

    2017-01-01

    Pulmonary fibrosis is characterized by the destruction of lung tissue architecture and the formation of fibrous foci, currently has no satisfactory treatment. Emodin is a component of Chinese herb that has been reported to be medicament on pancreatic fibrosis and liver fibrosis. However, its role in pulmonary fibrosis has not been established yet. In the present study, we investigated the hypothesis that Emodin plays an inhibitory role in TGF-β1 induced epithelial-mesenchymal transition (EMT) of alveolar epithelial cell, and Emodin exerts its effect through the Notch signaling pathway. Emodin inhibits the proliferation of Rat alveolar type II epithelial cells RLE-6TN in a concentration-dependent manner; reduces the expression of Collagen I, α-SMA and Vimentin, promotes the expression of E-cadherin. Moreover, Emodin could regulate the expression patterns of the Notch signaling pathway-related factors and reduce the Notch-1 nucleus translocation. Knockdown of Notch-1 enhances the inhibitory effect of Emodin on TGF-β1-induced EMT in RLE-6TN cells. In conclusion, the data of the present study suggests that Emodin suppresses TGF-β1-induced EMT in alveolar epithelial cells through Notch signaling pathway and shows the potential to be effective in the treatment of pulmonary fibrosis. - Highlights: • Emodin inhibits TGF-β1-induced EMT in alveolar epithelial cells. • Emodin regulates the expression patterns of the Notch signaling pathway-related factors. • Emodin inhibits TGF-β1-induced Notch-1 nucleus translocation and activation.

  13. Emodin suppresses TGF-β1-induced epithelial-mesenchymal transition in alveolar epithelial cells through Notch signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Rundi; Chen, Ruilin; Cao, Yu [Department of Respiration, The First Affiliated Hospital of Zhejiang Chinese Medicine University, NO. 56, Youdian Road, Shangcheng District, Hangzhou, Zhejiang Province 310006 (China); Wang, Yuan [Department of Pulmonary Function, The First Affiliated Hospital of Zhejiang Chinese Medicine University, NO. 56, Youdian Road, Shangcheng District, Hangzhou, Zhejiang Province 310006 (China); Song, Kang [Department of Respiration, The First Affiliated Hospital of Zhejiang Chinese Medicine University, NO. 56, Youdian Road, Shangcheng District, Hangzhou, Zhejiang Province 310006 (China); Zhang, Ya [Zhejiang Chinese Medicine University, No. 548, Binwen Road, Binjiang District, Hangzhou, Zhejiang Province 310006 (China); Yang, Junchao, E-mail: yangjunchaozj@zcmu.edu.cn [Department of Respiration, The First Affiliated Hospital of Zhejiang Chinese Medicine University, NO. 56, Youdian Road, Shangcheng District, Hangzhou, Zhejiang Province 310006 (China)

    2017-03-01

    Pulmonary fibrosis is characterized by the destruction of lung tissue architecture and the formation of fibrous foci, currently has no satisfactory treatment. Emodin is a component of Chinese herb that has been reported to be medicament on pancreatic fibrosis and liver fibrosis. However, its role in pulmonary fibrosis has not been established yet. In the present study, we investigated the hypothesis that Emodin plays an inhibitory role in TGF-β1 induced epithelial-mesenchymal transition (EMT) of alveolar epithelial cell, and Emodin exerts its effect through the Notch signaling pathway. Emodin inhibits the proliferation of Rat alveolar type II epithelial cells RLE-6TN in a concentration-dependent manner; reduces the expression of Collagen I, α-SMA and Vimentin, promotes the expression of E-cadherin. Moreover, Emodin could regulate the expression patterns of the Notch signaling pathway-related factors and reduce the Notch-1 nucleus translocation. Knockdown of Notch-1 enhances the inhibitory effect of Emodin on TGF-β1-induced EMT in RLE-6TN cells. In conclusion, the data of the present study suggests that Emodin suppresses TGF-β1-induced EMT in alveolar epithelial cells through Notch signaling pathway and shows the potential to be effective in the treatment of pulmonary fibrosis. - Highlights: • Emodin inhibits TGF-β1-induced EMT in alveolar epithelial cells. • Emodin regulates the expression patterns of the Notch signaling pathway-related factors. • Emodin inhibits TGF-β1-induced Notch-1 nucleus translocation and activation.

  14. Autophagy protects type II alveolar epithelial cells from Mycobacterium tuberculosis infection

    International Nuclear Information System (INIS)

    Guo, Xu-Guang; Ji, Tian-Xing; Xia, Yong; Ma, Yue-Yun

    2013-01-01

    Highlights: ► We investigated the protective effect of autophagy pathway against MTB infection. ► MTB-infected A549 cells had higher LDH release. ► Inhibition of autophagy signaling significantly enhanced the MTB-induced necrosis. ► Autophagy prevents apoptosis and promotes cell survival in infected cells. -- Abstract: This study was designed to investigate the protective effect of the autophagy signaling pathway against Mycobacterium tuberculosis infection in type II alveolar epithelial cells. An in vitro M. tuberculosis system was established using human A549 cells. Infection-induced changes in the expression of the autophagic marker LC3 were assessed by reverse transcription-PCR and Western blotting. Morphological changes in autophagosomes were detected by transmission electron microscopy (TEM). The function of the autophagy signaling pathway during infection was assessed by measuring the level of cell death and the amount of lactate dehydrogenase (LDH) released in the presence or absence of the inhibitor 3-methyladenine (3-MA). In addition, effects on LDH release were assessed after the siRNA-mediated knockdown of the essential autophagosomal structural membrane protein Atg5. LC3 mRNA expression was significantly reduced in M.tuberculosis-infected A549 cells (16888.76 ± 1576.34 vs. uninfected: 12744.29 ± 1089.37; P < 0.05). TEM revealed M.tuberculosis bacilli-containing compartments that were surrounded by double membranes characteristic of the autophagic process. M.tuberculosis-infected A549 cells released more LDH (1.45 ± 0.12 vs. uninfected: 0.45 ± 0.04; P < 0.05). The inhibition of autophagy signaling significantly enhanced M.tuberculosis-induced necrosis (3-MA: 75 ± 5% vs. untreated: 15 ± 1%; P < 0.05) and LDH release (3-MA: 2.50 ± 0.24 vs. untreated: 0.45 ± 0.04; Atg5 knockdown: 3.19 ± 0.29 vs. untreated: 1.28 ± 0.11; P < 0.05). Our results indicate that autophagy signaling pathway prevents apoptosis in type II alveolar epithelial cells

  15. A heteromeric molecular complex regulates the migration of lung alveolar epithelial cells during wound healing.

    Science.gov (United States)

    Ghosh, Manik C; Makena, Patrudu S; Kennedy, Joseph; Teng, Bin; Luellen, Charlean; Sinclair, Scott E; Waters, Christopher M

    2017-05-19

    Alveolar type II epithelial cells (ATII) are instrumental in early wound healing in response to lung injury, restoring epithelial integrity through spreading and migration. We previously reported in separate studies that focal adhesion kinase-1 (FAK) and the chemokine receptor CXCR4 promote epithelial repair mechanisms. However, potential interactions between these two pathways were not previously considered. In the present study, we found that wounding of rat ATII cells promoted increased association between FAK and CXCR4. In addition, protein phosphatase-5 (PP5) increased its association with this heteromeric complex, while apoptosis signal regulating kinase-1 (ASK1) dissociated from the complex. Cell migration following wounding was decreased when PP5 expression was decreased using shRNA, but migration was increased in ATII cells isolated from ASK1 knockout mice. Interactions between FAK and CXCR4 were increased upon depletion of ASK1 using shRNA in MLE-12 cells, but unaffected when PP5 was depleted. Furthermore, we found that wounded rat ATII cells exhibited decreased ASK1 phosphorylation at Serine-966, decreased serine phosphorylation of FAK, and decreased association of phosphorylated ASK1 with FAK. These changes in phosphorylation were dependent upon expression of PP5. These results demonstrate a unique molecular complex comprising CXCR4, FAK, ASK1, and PP5 in ATII cells during wound healing.

  16. Vacuolar ATPase regulates surfactant secretion in rat alveolar type II cells by modulating lamellar body calcium.

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    Narendranath Reddy Chintagari

    2010-02-01

    Full Text Available Lung surfactant reduces surface tension and maintains the stability of alveoli. How surfactant is released from alveolar epithelial type II cells is not fully understood. Vacuolar ATPase (V-ATPase is the enzyme responsible for pumping H(+ into lamellar bodies and is required for the processing of surfactant proteins and the packaging of surfactant lipids. However, its role in lung surfactant secretion is unknown. Proteomic analysis revealed that vacuolar ATPase (V-ATPase dominated the alveolar type II cell lipid raft proteome. Western blotting confirmed the association of V-ATPase a1 and B1/2 subunits with lipid rafts and their enrichment in lamellar bodies. The dissipation of lamellar body pH gradient by Bafilomycin A1 (Baf A1, an inhibitor of V-ATPase, increased surfactant secretion. Baf A1-stimulated secretion was blocked by the intracellular Ca(2+ chelator, BAPTA-AM, the protein kinase C (PKC inhibitor, staurosporine, and the Ca(2+/calmodulin-dependent protein kinase II (CaMKII, KN-62. Baf A1 induced Ca(2+ release from isolated lamellar bodies. Thapsigargin reduced the Baf A1-induced secretion, indicating cross-talk between lamellar body and endoplasmic reticulum Ca(2+ pools. Stimulation of type II cells with surfactant secretagogues dissipated the pH gradient across lamellar bodies and disassembled the V-ATPase complex, indicating the physiological relevance of the V-ATPase-mediated surfactant secretion. Finally, silencing of V-ATPase a1 and B2 subunits decreased stimulated surfactant secretion, indicating that these subunits were crucial for surfactant secretion. We conclude that V-ATPase regulates surfactant secretion via an increased Ca(2+ mobilization from lamellar bodies and endoplasmic reticulum, and the activation of PKC and CaMKII. Our finding revealed a previously unrealized role of V-ATPase in surfactant secretion.

  17. S-carboxymethylcysteine inhibits adherence of Streptococcus pneumoniae to human alveolar epithelial cells.

    Science.gov (United States)

    Sumitomo, Tomoko; Nakata, Masanobu; Yamaguchi, Masaya; Terao, Yutaka; Kawabata, Shigetada

    2012-01-01

    Streptococcus pneumoniae is a major pathogen of respiratory infections that utilizes platelet-activating factor receptor (PAFR) for firm adherence to host cells. The mucolytic agent S-carboxymethylcysteine (S-CMC) has been shown to exert inhibitory effects against infection by several respiratory pathogens including S. pneumoniae in vitro and in vivo. Moreover, clinical studies have implicated the benefits of S-CMC in preventing exacerbation of chronic obstructive pulmonary disease, which is considered to be related to respiratory infections. In this study, to assess whether the potency of S-CMC is attributable to inhibition of pneumococcal adherence to host cells, an alveolar epithelial cell line stimulated with interleukin-1α was used as a model of inflamed epithelial cells. Despite upregulation of PAFR by inflammatory activation, treatment with S-CMC efficiently inhibited pneumococcal adherence to host epithelial cells. In order to gain insight into the inhibitory mechanism, the effects of S-CMC on PAFR expression were also investigated. Following treatment with S-CMC, PAFR expression was reduced at both mRNA and post-transcriptional levels. Interestingly, S-CMC was also effective in inhibiting pneumococcal adherence to cells transfected with PAFR small interfering RNAs. These results indicate S-CMC as a probable inhibitor targeting numerous epithelial receptors that interact with S. pneumoniae.

  18. Cytotoxicity and gene expression profiling of polyhexamethylene guanidine hydrochloride in human alveolar A549 cells.

    Science.gov (United States)

    Jung, Ha-Na; Zerin, Tamanna; Podder, Biswajit; Song, Ho-Yeon; Kim, Yong-Sik

    2014-06-01

    In Korea, lung disease of children and pregnant women associated with humidifier disinfectant use has become a major concern. A common sterilizer is polyhexamethylene guanidine (PHMG), a member of the guanidine family of antiseptics. This study was done to elucidate the putative cytotoxic effect of PHMG and the PHMG-mediated altered gene expression in human alveolar epithelial A549 cells in vitro. Cell viability analyses revealed the potent cytotoxicity of PHMG, with cell death evident at as low as 5 μg/mL. Death was dose- and time-dependent, and was associated with formation of intracellular reactive oxygen species, and apoptosis significantly, at even 2 μg/mL concentration. The gene expression profile in A549 cells following 24 h exposure to 5 μg/mL of PHMG was investigated using DNA microarray analysis. Changes in gene expression relevant to the progression of cell death included induction of genes related to apoptosis, autophagy, fibrosis, and cell cycle. However, the expressions of genes encoding antioxidant and detoxifying enzymes were down-regulated or not affected. The altered expression of selected genes was confirmed by quantitative reverse transcription-polymerase chain reaction and Western blot analyses. The collective data suggest that PHMG confers cellular toxicity through the generation of intracellular reactive oxygen species and alteration of gene expression. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Macrophage-expressed IFN-β contributes to apoptotic alveolar epithelial cell injury in severe influenza virus pneumonia.

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    Katrin Högner

    2013-02-01

    Full Text Available Influenza viruses (IV cause pneumonia in humans with progression to lung failure and fatal outcome. Dysregulated release of cytokines including type I interferons (IFNs has been attributed a crucial role in immune-mediated pulmonary injury during severe IV infection. Using ex vivo and in vivo IV infection models, we demonstrate that alveolar macrophage (AM-expressed IFN-β significantly contributes to IV-induced alveolar epithelial cell (AEC injury by autocrine induction of the pro-apoptotic factor TNF-related apoptosis-inducing ligand (TRAIL. Of note, TRAIL was highly upregulated in and released from AM of patients with pandemic H1N1 IV-induced acute lung injury. Elucidating the cell-specific underlying signalling pathways revealed that IV infection induced IFN-β release in AM in a protein kinase R- (PKR- and NF-κB-dependent way. Bone marrow chimeric mice lacking these signalling mediators in resident and lung-recruited AM and mice subjected to alveolar neutralization of IFN-β and TRAIL displayed reduced alveolar epithelial cell apoptosis and attenuated lung injury during severe IV pneumonia. Together, we demonstrate that macrophage-released type I IFNs, apart from their well-known anti-viral properties, contribute to IV-induced AEC damage and lung injury by autocrine induction of the pro-apoptotic factor TRAIL. Our data suggest that therapeutic targeting of the macrophage IFN-β-TRAIL axis might represent a promising strategy to attenuate IV-induced acute lung injury.

  20. Quantitation and renewal of alveolar and bronchiolar cell populations of rat lungs. Changes during some pathological processes

    International Nuclear Information System (INIS)

    Fritsch, Paul.

    1979-02-01

    The various cells of alveolar and bronchiolar tissues of rat lungs were studied qualitatively and quantitatively. In physiological conditions, the renewal rate of the cell populations is low and the frequency of the various cell types is constant. This stability, especially at the level of the alveolar tissue, was also found during the latency period and the development of radiation-induced lung cancers. A particular cellular population was demonstrated: marginated leukocyte pool at the level of the pulmonary circulation. This pool was different both qualitatively and quantitatively from the leukocytes of the systemic circulation and, in physiological conditions, behaved as a cellular reservoir of monocytes chiefly re-distributed according to the body needs. In pathological conditions, its fast migration contributed to the defence of the alveolar medium. A quantitative study of the renewal of alveolar macrophages showed that under 1 p. cent of the marginated leukocyte pool is used daily to keep up this population. This fraction undergoes a maturation stage by cellular division within the endoalveolar medium. In some pathological conditions, this division can be completely inhibited [fr

  1. Pulmonary surfactant and its components inhibit secretion of phosphatidylcholine from cultured rat alveolar type II cells

    International Nuclear Information System (INIS)

    Dobbs, L.G.; Wright, J.R.; Hawgood, S.; Gonzalez, R.; Venstrom, K.; Nellenbogen, J.

    1987-01-01

    Pulmonary surfactant is synthesized and secreted by alveolar type II cells. Radioactive phosphatidylcholine has been used as a marker for surfactant secretion. The authors report findings that suggest that surfactant inhibits secretion of 3 H-labeled phosphatidylcholine by cultured rat type II cells. The lipid components and the surfactant protein group of M/sub r/ 26,000-36,000 (SP 26-36) inhibit secretion to different extents. Surfactant lipids do not completely inhibit release; in concentrations of 100 μg/ml, lipids inhibit stimulated secretion by 40%. SP 26-36 inhibits release with an EC 50 of 0.1 μg/ml. At concentrations of 1.0 μg/ml, SP 26-36 inhibits basal secretion and reduces to basal levels secretion stimulated by terbutaline, phorbol 12-myristate 13-acetate, and the ionophore A23187. The inhibitory effect of SP 26-36 can be blocked by washing type II cells after adding SP 26-36, by heating the proteins to 100 0 C for 10 min, by adding antiserum specific to SP 26-36, or by incubating cells in the presence of 0.2 mM EGTA. SP 26-36 isolated from canine and human sources also inhibits phosphatidylcholine release from rat type II cells. Neither type I collagen nor serum apolipoprotein A-1 inhibits secretion. These findings are compatible with the hypothesis that surfactant secretion is under feedback regulatory control

  2. Mitochondrial catalase overexpressed transgenic mice are protected against lung fibrosis in part via preventing alveolar epithelial cell mitochondrial DNA damage.

    Science.gov (United States)

    Kim, Seok-Jo; Cheresh, Paul; Jablonski, Renea P; Morales-Nebreda, Luisa; Cheng, Yuan; Hogan, Erin; Yeldandi, Anjana; Chi, Monica; Piseaux, Raul; Ridge, Karen; Michael Hart, C; Chandel, Navdeep; Scott Budinger, G R; Kamp, David W

    2016-12-01

    Alveolar epithelial cell (AEC) injury and mitochondrial dysfunction are important in the development of lung fibrosis. Our group has shown that in the asbestos exposed lung, the generation of mitochondrial reactive oxygen species (ROS) in AEC mediate mitochondrial DNA (mtDNA) damage and apoptosis which are necessary for lung fibrosis. These data suggest that mitochondrial-targeted antioxidants should ameliorate asbestos-induced lung. To determine whether transgenic mice that express mitochondrial-targeted catalase (MCAT) have reduced lung fibrosis following exposure to asbestos or bleomycin and, if so, whether this occurs in association with reduced AEC mtDNA damage and apoptosis. Crocidolite asbestos (100µg/50µL), TiO 2 (negative control), bleomycin (0.025 units/50µL), or PBS was instilled intratracheally in 8-10 week-old wild-type (WT - C57Bl/6J) or MCAT mice. The lungs were harvested at 21d. Lung fibrosis was quantified by collagen levels (Sircol) and lung fibrosis scores. AEC apoptosis was assessed by cleaved caspase-3 (CC-3)/Surfactant protein C (SFTPC) immunohistochemistry (IHC) and semi-quantitative analysis. AEC (primary AT2 cells from WT and MCAT mice and MLE-12 cells) mtDNA damage was assessed by a quantitative PCR-based assay, apoptosis was assessed by DNA fragmentation, and ROS production was assessed by a Mito-Sox assay. Compared to WT, crocidolite-exposed MCAT mice exhibit reduced pulmonary fibrosis as measured by lung collagen levels and lung fibrosis score. The protective effects in MCAT mice were accompanied by reduced AEC mtDNA damage and apoptosis. Similar findings were noted following bleomycin exposure. Euk-134, a mitochondrial SOD/catalase mimetic, attenuated MLE-12 cell DNA damage and apoptosis. Finally, compared to WT, asbestos-induced MCAT AT2 cell ROS production was reduced. Our finding that MCAT mice have reduced pulmonary fibrosis, AEC mtDNA damage and apoptosis following exposure to asbestos or bleomycin suggests an important role

  3. Amiodarone increases the accumulation of DEA in a human alveolar epithelium-derived cell line.

    Science.gov (United States)

    Seki, Satoru; Itagaki, Shirou; Kobayashi, Masaki; Hirano, Takeshi; Iseki, Ken

    2008-07-01

    Amiodarone (AMD)-induced pulmonary toxicity (AIPT) is the most life-threatening side-effect of AMD treatment. N-Monodesethylamiodarone (DEA), an active metabolite of AMD, also exhibits cytotoxicity and tends to accumulate in the lung more intensively than AMD. In this study, we characterized the mechanism of DEA accumulation using A549 cells as a model of the alveolar epithelium. Typical ATP-depletion compounds caused an approximately 30% increase in the accumulation of DEA in A549 cells, although these effects were less than those in Caco-2 cells. Triiodothyronine (T(3)), which exhibited an inhibitory effect on DEA efflux in Caco-2 cells, did not affect the accumulation of DEA in A549 cells. On the other hand, 100 microM AMD caused an approximately 200% increase in DEA content in A549 cells, although AMD accumulation was not affected by 100 microM DEA. Since the reducing effect of AMD on cellular ATP levels and that of FCCP were similar, the mechanism by which DEA accumulation is increased by AMD might be different from the ATP-dependent DEA efflux mechanism. The decrease in cell viability by DEA in the presence of AMD (IC(50) value of DEA for A549 cell viability: 25.4+/-2.4 microM) was more pronounced than that by DEA alone (IC(50) value: 11.5+/-3.0 microM). This further DEA accumulation by AMD might be a factor responsible for the greater accumulation of DEA than that of AMD in the lung in long-term AMD-treated patients.

  4. Injurious effects of wool and grain dusts on alveolar epithelial cells and macrophages in vitro.

    Science.gov (United States)

    Brown, D M; Donaldson, K

    1991-01-01

    Epidemiological studies of workers in wool textile mills have shown a direct relation between the concentration of wool dust in the air and respiratory symptoms. Injurious effects of wool dust on the bronchial epithelium could be important in causing inflammation and irritation. A pulmonary epithelial cell line in vitro was therefore used to study the toxic effects of wool dust. Cells of the A549 epithelial cell line were labelled with 51Cr and treated with whole wool dusts and extracts of wool, after which injury was assessed. Also, the effects of grain dust, which also causes a form of airway obstruction, were studied. The epithelial injury was assessed by measuring 51Cr release from cells as an indication of lysis, and by monitoring cells which had detached from the substratum. No significant injury to A549 cells was caused by culture with any of the dusts collected from the air but surface "ledge" dust caused significant lysis at some doses. Quartz, used as a toxic control dust, caused significant lysis at the highest concentration of 100 micrograms/well. To determine whether any injurious material was soluble the dusts were incubated in saline and extracts collected. No extracts caused significant injury to epithelial cells. A similar lack of toxicity was found when 51Cr labelled control alveolar macrophages were targets for injury. Significant release of radiolabel was evident when macrophages were exposed to quartz at concentrations of 10 and 20 micrograms/well, there being no significant injury with either wool or grain dusts. These data suggest that neither wool nor grain dust produce direct injury to epithelial cells, and further studies are necessary to explain inflammation leading to respiratory symptoms in wool and grain workers. PMID:2015211

  5. An in vitro cytotoxicity assessment of graphene nanosheets on alveolar cells

    Science.gov (United States)

    Dervin, Saoirse; Murphy, James; Aviles, Ruth; Pillai, Suresh C.; Garvey, Mary

    2018-03-01

    The collection of intrinsic properties possessed by graphene family nanomaterials (GFNs) results in their continuous exploitation for biomedical applications. The materials biomedical potential has motivated an upsurge in green preparation routes for the production of graphene like materials with limited toxicity. A number of bio-friendly reducing agents have been utilized for the preparation of chemically reduced graphene oxide (GO), and their resulting cytotoxic effects examined. However, the toxicology effects of one of the first biomolecules implemented for the reduction of GO, ascorbic acid (AA) has yet to be investigated. Herein, the toxicity of three distinct GFNs; GO, hydrazine reduced GO (H.rGO) and AA.rGO, prepared through diverse chemical routes are studied, to demonstrate the cytotoxic activity of a green reducer, in comparison to an established reduction method using hydrazine hydrate. The variation in atomic structure of GO, H.rGO and AA.rGO resulting from different synthesis techniques demonstrates the dependence of toxicity on particle shape and size. All GFNs induced high levels of alveolar cell toxicity. Interaction of AA.rGO with the A549 human lung epithelial carcinoma cell line resulted in increased leakage of lactate dehydrogenase, indicative of diminished cell membrane integrity. The uncharacteristic shape of the AA.rGO may be responsible for this proliferated release of the essential protein. The presented data therefore demonstrates that modification of synthetic processes significantly alter the biological activities of GFNs.

  6. Morphometric Characterization of Rat and Human Alveolar Macrophage Cell Models and their Response to Amiodarone using High Content Image Analysis.

    Science.gov (United States)

    Hoffman, Ewelina; Patel, Aateka; Ball, Doug; Klapwijk, Jan; Millar, Val; Kumar, Abhinav; Martin, Abigail; Mahendran, Rhamiya; Dailey, Lea Ann; Forbes, Ben; Hutter, Victoria

    2017-12-01

    Progress to the clinic may be delayed or prevented when vacuolated or "foamy" alveolar macrophages are observed during non-clinical inhalation toxicology assessment. The first step in developing methods to study this response in vitro is to characterize macrophage cell lines and their response to drug exposures. Human (U937) and rat (NR8383) cell lines and primary rat alveolar macrophages obtained by bronchoalveolar lavage were characterized using high content fluorescence imaging analysis quantification of cell viability, morphometry, and phospholipid and neutral lipid accumulation. Cell health, morphology and lipid content were comparable (p content. Responses to amiodarone, a known inducer of phospholipidosis, required analysis of shifts in cell population profiles (the proportion of cells with elevated vacuolation or lipid content) rather than average population data which was insensitive to the changes observed. A high content image analysis assay was developed and used to provide detailed morphological characterization of rat and human alveolar-like macrophages and their response to a phospholipidosis-inducing agent. This provides a basis for development of assays to predict or understand macrophage vacuolation following inhaled drug exposure.

  7. Interactions of Francisella tularensis with Alveolar Type II Epithelial Cells and the Murine Respiratory Epithelium.

    Directory of Open Access Journals (Sweden)

    Matthew Faron

    Full Text Available Francisella tularensis is classified as a Tier 1 select agent by the CDC due to its low infectious dose and the possibility that the organism can be used as a bioweapon. The low dose of infection suggests that Francisella is unusually efficient at evading host defenses. Although ~50 cfu are necessary to cause human respiratory infection, the early interactions of virulent Francisella with the lung environment are not well understood. To provide additional insights into these interactions during early Francisella infection of mice, we performed TEM analysis on mouse lungs infected with F. tularensis strains Schu S4, LVS and the O-antigen mutant Schu S4 waaY::TrgTn. For all three strains, the majority of the bacteria that we could detect were observed within alveolar type II epithelial cells at 16 hours post infection. Although there were no detectable differences in the amount of bacteria within an infected cell between the three strains, there was a significant increase in the amount of cellular debris observed in the air spaces of the lungs in the Schu S4 waaY::TrgTn mutant compared to either the Schu S4 or LVS strain. We also studied the interactions of Francisella strains with human AT-II cells in vitro by characterizing the ability of these three strains to invade and replicate within these cells. Gentamicin assay and confocal microscopy both confirmed that F. tularensis Schu S4 replicated robustly within these cells while F. tularensis LVS displayed significantly lower levels of growth over 24 hours, although the strain was able to enter these cells at about the same level as Schu S4 (1 organism per cell, as determined by confocal imaging. The Schu S4 waaY::TrgTn mutant that we have previously described as attenuated for growth in macrophages and mouse virulence displayed interesting properties as well. This mutant induced significant airway inflammation (cell debris and had an attenuated growth phenotype in the human AT-II cells. These

  8. The Role of Mitochondrial DNA in Mediating Alveolar Epithelial Cell Apoptosis and Pulmonary Fibrosis

    Science.gov (United States)

    Kim, Seok-Jo; Cheresh, Paul; Jablonski, Renea P.; Williams, David B.; Kamp, David W.

    2015-01-01

    Convincing evidence has emerged demonstrating that impairment of mitochondrial function is critically important in regulating alveolar epithelial cell (AEC) programmed cell death (apoptosis) that may contribute to aging-related lung diseases, such as idiopathic pulmonary fibrosis (IPF) and asbestosis (pulmonary fibrosis following asbestos exposure). The mammalian mitochondrial DNA (mtDNA) encodes for 13 proteins, including several essential for oxidative phosphorylation. We review the evidence implicating that oxidative stress-induced mtDNA damage promotes AEC apoptosis and pulmonary fibrosis. We focus on the emerging role for AEC mtDNA damage repair by 8-oxoguanine DNA glycosylase (OGG1) and mitochondrial aconitase (ACO-2) in maintaining mtDNA integrity which is important in preventing AEC apoptosis and asbestos-induced pulmonary fibrosis in a murine model. We then review recent studies linking the sirtuin (SIRT) family members, especially SIRT3, to mitochondrial integrity and mtDNA damage repair and aging. We present a conceptual model of how SIRTs modulate reactive oxygen species (ROS)-driven mitochondrial metabolism that may be important for their tumor suppressor function. The emerging insights into the pathobiology underlying AEC mtDNA damage and apoptosis is suggesting novel therapeutic targets that may prove useful for the management of age-related diseases, including pulmonary fibrosis and lung cancer. PMID:26370974

  9. In vivo autoradiographic demonstration of β-adrenergic binding sites in adult rat type II alveolar epithelial cells

    International Nuclear Information System (INIS)

    Smith, D.M.; Sidhu, M.K.

    1984-01-01

    Adult male rats were injected intravenously with the muscarinic binding probe 3 H-Quinuclidinyl benzilate (QNB) or the β-adrenergic probe 3 H-dihydroalprenolol (DHA). Other rats were pre-treated with an intraperitoneal injection of a 500-fold excess of L-isoproterenol prior to the DHA. Light microscopic autoradiography of 0.5 μm sections of lung from the QNB group demonstrated very little labelling even after 6 months of exposure. In constrast, trachealis smooth muscle from these animals contained substantial labelling. Autoradiographs of lung from rats injected with DHA demonstrated labelling which was well localized over alveolar septa and concentrated over the cytoplasm of type II cells. Quantitative analysis of labelling in the DHA groups indicated a significant reduction of labelling in animals treated with L-isoproterenol prior to DHA, in both the alveolar parenchyma in general and over type II cells. The results of this study provide morphologic evidence for the uptake and specific binding of β-adrenergic antagonists by the adult lung in vivo, while failing to demonstrate similar binding of a muscarinic probe. In addition, the results demonstrate specific β-adrenergic receptors on type II cells in vivo and substantiate the view of a direct effect of β-adrenergic agonists on alveolar type II cells

  10. Differential Regulation of Gene Expression of Alveolar Epithelial Cell Markers in Human Lung Adenocarcinoma-Derived A549 Clones

    Directory of Open Access Journals (Sweden)

    Hiroshi Kondo

    2015-01-01

    Full Text Available Stem cell therapy appears to be promising for restoring damaged or irreparable lung tissue. However, establishing a simple and reproducible protocol for preparing lung progenitor populations is difficult because the molecular basis for alveolar epithelial cell differentiation is not fully understood. We investigated an in vitro system to analyze the regulatory mechanisms of alveolus-specific gene expression using a human alveolar epithelial type II (ATII cell line, A549. After cloning A549 subpopulations, each clone was classified into five groups according to cell morphology and marker gene expression. Two clones (B7 and H12 were further analyzed. Under serum-free culture conditions, surfactant protein C (SPC, an ATII marker, was upregulated in both H12 and B7. Aquaporin 5 (AQP5, an ATI marker, was upregulated in H12 and significantly induced in B7. When the RAS/MAPK pathway was inhibited, SPC and thyroid transcription factor-1 (TTF-1 expression levels were enhanced. After treatment with dexamethasone (DEX, 8-bromoadenosine 3′5′-cyclic monophosphate (8-Br-cAMP, 3-isobutyl-1-methylxanthine (IBMX, and keratinocyte growth factor (KGF, surfactant protein B and TTF-1 expression levels were enhanced. We found that A549-derived clones have plasticity in gene expression of alveolar epithelial differentiation markers and could be useful in studying ATII maintenance and differentiation.

  11. Biomineralisation with Saos-2 bone cells on TiSiN sputtered Ti alloys.

    Science.gov (United States)

    V V, Anusha Thampi; Bendavid, Avi; Martin, P J; Vaithilingam, Vijay; Bean, Penelope A; Evans, Margaret D M; Subramanian, B

    2017-07-01

    Surface modifications of metallic implants are important in order to protect the underlying metals from the harsh corrosive environment inside the human body and to minimize the losses caused by wear. Recently, researches are carried out in developing bioactive surfaces on metallic implants, which supports the growth and proliferation of cells on to these surfaces. Titanium silicon nitride (TiSiN) hard nanocomposites thin films were fabricated on Ti alloys (Ti-6Al-4V) by pulsed direct current (DC) reactive magnetron sputtering. The films were characterized for its microstructural and electrochemical behavior. The higher charge transfer resistance (Rct) and positive shift in Ecorr value of TiSiN/Ti alloys than the bare Ti-alloys indicates a better corrosion resistance offered by the TiSiN thin films to the underlying substrates. The biological response to TiSiN/Ti alloys and control bare Ti-alloys was measured in vitro using cell-based assays with two main outcomes. Firstly, neither the Ti alloy nor the TiSiN thin film was cytotoxic to cells. Secondly, the TiSiN thin film promoted differentiation of human bone cells above the bare control Ti alloy as measured by alkaline phosphatase and calcium production. TiSiN thin films provide better corrosion resistance and protect the underlying metal from the corrosive environment. The thin film surface is both biocompatible and bioactive as indicated from the cytotoxicity and biomineralization studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Effect of SLC34A2 gene mutation on extracellular phosphorus transport in PAM alveolar epithelial cells.

    Science.gov (United States)

    Ma, Tiangang; Qu, Danhua; Yan, Bingdi; Zhang, Qinghua; Ren, Jin; Hu, Yanbing

    2018-01-01

    A mutation in the IIb sodium phosphate transporter SLC34A2 gene has recently been described in pulmonary alveolar microlithiasis (PAM) patients. Experiments in this study were aimed at confirming the role of the gene product in PAM by comparing phosphorylated products in extracellular fluid of alveolar epithelial cells overexpressing the SLC34A2 gene or its mutated version. Eukaryotic expression vectors were constructed and transfected into A549 human alveolar epithelial cells. There were three groups of cells including those transfected with empty vector plasmid pcDNA3.1(+) (plasmid control group), those transfected with normal SLC34A2 gene expressed from pcDNA3.1 (normal control group), and those transfected with a version of the PAM SLC34A2 gene linked to the pcDNA3.1(+) (PAM group). Transfection efficiencies were detected by reverse transcription-polymerase chain reaction (RT-PCR). At 48 h after transfection, the concentration of inorganic phosphorus in the culture medium was detected using an automatic biochemical analyzer. Our results showed the concentration of inorganic phosphorus in the supernatant of the normal control group was significantly lower than that in the plasmid control and PAM groups (PPAM group was significantly lower than that in the plasmid control group (PPAM patients, given that the function of the phosphate transporter seems to be affected and it is conceivable that it would lead to extracellular fluid alterations in vivo .

  13. Mast cell granules modulate alveolar macrophage respiratory-burst activity and eicosanoid metabolism.

    Science.gov (United States)

    Rock, M J; Despot, J; Lemanske, R F

    1990-10-01

    Alveolar macrophages (AMs) and mast cells reside in the airway, and both have been demonstrated to contribute independently to allergic inflammatory responses through the generation of respiratory-burst metabolites and the release of biologically active mediators, respectively. Since mast cell granules (MCGs) contain mediators that could potentially interact with the AM respiratory burst, we investigated the effects of isolated MCGs on this important inflammatory pathway of the AM. MCGs and AMs were obtained by peritoneal and tracheoalveolar lavage, respectively, of Sprague-Dawley rats. First, the overall respiratory-burst activity was measured by luminal-enhanced chemiluminescence (CL), and second, the individual oxygen species contributing to CL (superoxide anion [O2-], hydrogen peroxide [H2O2], and hypochlorous acid) were measured. MCGs alone enhanced AM CL responses to an equivalent degree compared to zymosan-stimulated AMs. However, AMs preincubated with MCGs followed by zymosan stimulation significantly and synergistically enhanced the CL responses. This enhanced CL was not due to an increased production of O2-, H2O2, or hypochlorous acid; in fact, there were decreased measured amounts of O2- and H2O2 from zymosan-stimulated AMs in the presence of MCGs, most likely caused by the content of granules of superoxide dismutase and peroxidase, respectively. The lipoxygenase inhibitor, nordihydroguaiaretic acid, completely abolished the enhanced CL of AM preincubated with MCGs and subsequently stimulated by zymosan, but O2- production was not affected by nordihydroguaiaretic acid. Taken together, these results suggest that derivatives of arachidonic acid metabolism, most likely those of the lipoxygenase pathway, are responsible for the enhanced AM CL response observed in the presence of MCGs. Thus, mast cell-macrophage interactions may be important within the airway in enhancing the generation of mediators that contribute to tissue inflammation and bronchospasm.

  14. Modulation pf pulmonary surfactant secretion from alveolar type II cells by cytoplasmic free calcium ([Ca2+]/sub i/)

    International Nuclear Information System (INIS)

    Sano, K.; Voelker, D.R.; Mason, R.J.

    1986-01-01

    Ca 2+ is regulator of a variety of cellular functions including exocytosis. TPA and terbutaline have been shown to stimulate surfactant secretion from alveolar type II cells. The authors examined changes in [Ca 2+ ]/sub i/ and surfactant secretion by secretagogues in primary culture of alveolar type II cells. Cells were isolated from adult rats and were cultured for 24 h with 3 H-choline to label phosphatidylcholine. Percent secretion was determined by counting the lipids of cells and medium; cytotoxicity was excluded by measuring lactate dehydrogenase as cells and medium. [Ca 2+ ]/sub i/ was determined by measuring quin2 fluroescence of cells cultured on a glass coverslip. Ionomycin increased secretion as well as [Ca 2+ ] in dose dependent manner at the concentration from 25 to 400 nM. Ionomycin (50 nM) increased terbutaline-induced secretion in a synergistic manner but only increased TPA-induced secretion in an additive manner. Terbutaline mobilized [Ca 2+ ]/sub i/ from intracellular stores and increased [Ca 2+ ]/sub i/ by 20% from a basal level of 140 nM. TPA itself did not change [Ca 2+ ]/sub i/ but inhibited the effect of terbutaline on [Ca 2+ ]/sub i/. Loading of quin2 in the absence of extracellular calcium lowered [Ca 2+ ]/sub i/ from 143 nM to 31 nM. Lowering [Ca 2+ ]/sub i/ inhibited TPA- or terbutaline-induced secretion by 22% and 40% respectively. These results indicate that [Ca 2+ ]/sub i/ effects cAMp-induced secretion more than protein kinase C-mediated secretion in alveolar type II cells

  15. Secretory activity and cell cycle alteration of alveolar type II cells in the early and late phase after irradiation

    International Nuclear Information System (INIS)

    Willner, Jochen; Vordermark, Dirk; Schmidt, Michael; Gassel, Andreamaria; Flentje, Michael; Wirtz, Hubert

    2003-01-01

    Purpose: Type II cells and the surfactant system have been proposed to play a central role in pathogenesis of radiation pneumonitis. We analyzed the secretory function and proliferation parameters of alveolar type II cells in the early (until 24 h) and late phase (1-5 weeks) after irradiation (RT) in vitro and in vivo. Methods and Materials: Type II cells were isolated from rats according to the method of Dobbs. Stimulation of secretion was induced with terbutaline, adenosine triphosphate (ATP), and 12-O-tetradecanoylphorbol-13-acetate (TPA) for a 2-h period. Determination of secretion was performed using 3 H-labeled phosphatidylcholine. For the early-phase analysis, freshly isolated and adherent type II cells were irradiated in vitro with 9-21 Gy (stepwise increase of 3 Gy). Secretion stimulation was initiated 1, 6, 24, and 48 h after RT. For late-phase analysis, type II cells were isolated 1-5 weeks after 18 Gy whole lung or sham RT. Each experiment was repeated at least fivefold. Flow cytometry was used to determine cell cycle distribution and proliferating cell nuclear antigen index. Results: During the early-phase (in vitro) analysis, we found a normal stimulation of surfactant secretion in irradiated, as well as unirradiated, cells. No change in basal secretion and no dose effect were seen. During the late phase, 1-5 weeks after whole lung RT, we observed enhanced secretory activity for all secretagogues and a small increase in basal secretion in Weeks 3 and 4 (pneumonitis phase) compared with controls. The total number of isolated type II cells, as well as the rate of viable cells, decreased after the second post-RT week. Cell cycle alterations suggesting an irreversible G 2 /M block occurred in the second post-RT week and did not resolve during the observation period. The proliferating cell nuclear antigen index of type II cells from irradiated rats did not differ from that of controls. Conclusion: In contrast to literature data, we observed no direct

  16. Differential replication of avian influenza H9N2 viruses in human alveolar epithelial A549 cells

    Directory of Open Access Journals (Sweden)

    Peiris Malik

    2010-03-01

    Full Text Available Abstract Avian influenza virus H9N2 isolates cause a mild influenza-like illness in humans. However, the pathogenesis of the H9N2 subtypes in human remains to be investigated. Using a human alveolar epithelial cell line A549 as host, we found that A/Quail/Hong Kong/G1/97 (H9N2/G1, which shares 6 viral "internal genes" with the lethal A/Hong Kong/156/97 (H5N1/97 virus, replicates efficiently whereas other H9N2 viruses, A/Duck/Hong Kong/Y280/97 (H9N2/Y280 and A/Chicken/Hong Kong/G9/97 (H9N2/G9, replicate poorly. Interestingly, we found that there is a difference in the translation of viral protein but not in the infectivity or transcription of viral genes of these H9N2 viruses in the infected cells. This difference may possibly be explained by H9N2/G1 being more efficient on viral protein production in specific cell types. These findings suggest that the H9N2/G1 virus like its counterpart H5N1/97 may be better adapted to the human host and replicates efficiently in human alveolar epithelial cells.

  17. DJ-1 Modulates Nuclear Erythroid 2-Related Factor-2-Mediated Protection in Human Primary Alveolar Type II Cells in Smokers.

    Science.gov (United States)

    Bahmed, Karim; Messier, Elise M; Zhou, Wenbo; Tuder, Rubin M; Freed, Curt R; Chu, Hong Wei; Kelsen, Steven G; Bowler, Russell P; Mason, Robert J; Kosmider, Beata

    2016-09-01

    Cigarette smoke (CS) is a main source of oxidative stress and a key risk factor for emphysema, which consists of alveolar wall destruction. Alveolar type (AT) II cells are in the gas exchange regions of the lung. We isolated primary ATII cells from deidentified organ donors whose lungs were not suitable for transplantation. We analyzed the cell injury obtained from nonsmokers, moderate smokers, and heavy smokers. DJ-1 protects cells from oxidative stress and induces nuclear erythroid 2-related factor-2 (Nrf2) expression, which activates the antioxidant defense system. In ATII cells isolated from moderate smokers, we found DJ-1 expression by RT-PCR, and Nrf2 and heme oxygenase (HO)-1 translocation by Western blotting and immunocytofluorescence. In ATII cells isolated from heavy smokers, we detected Nrf2 and HO-1 cytoplasmic localization. Moreover, we found high oxidative stress, as detected by 4-hydroxynonenal (4-HNE) (immunoblotting), inflammation by IL-8 and IL-6 levels by ELISA, and apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay in ATII cells obtained from heavy smokers. Furthermore, we detected early DJ-1 and late Nrf2 expression after ATII cell treatment with CS extract. We also overexpressed DJ-1 by adenovirus construct and found that this restored Nrf2 and HO-1 expression and induced nuclear translocation in heavy smokers. Moreover, DJ-1 overexpression also decreased ATII cell apoptosis caused by CS extract in vitro. Our results indicate that DJ-1 activates the Nrf2-mediated antioxidant defense system. Furthermore, DJ-1 overexpression can restore the impaired Nrf2 pathway, leading to ATII cell protection in heavy smokers. This suggests a potential therapeutic strategy for targeting DJ-1 in CS-related lung diseases.

  18. Exogenous surfactant application in a rat lung ischemia reperfusion injury model: effects on edema formation and alveolar type II cells

    Directory of Open Access Journals (Sweden)

    Richter Joachim

    2008-01-01

    Full Text Available Abstract Background Prophylactic exogenous surfactant therapy is a promising way to attenuate the ischemia and reperfusion (I/R injury associated with lung transplantation and thereby to decrease the clinical occurrence of acute lung injury and acute respiratory distress syndrome. However, there is little information on the mode by which exogenous surfactant attenuates I/R injury of the lung. We hypothesized that exogenous surfactant may act by limiting pulmonary edema formation and by enhancing alveolar type II cell and lamellar body preservation. Therefore, we investigated the effect of exogenous surfactant therapy on the formation of pulmonary edema in different lung compartments and on the ultrastructure of the surfactant producing alveolar epithelial type II cells. Methods Rats were randomly assigned to a control, Celsior (CE or Celsior + surfactant (CE+S group (n = 5 each. In both Celsior groups, the lungs were flush-perfused with Celsior and subsequently exposed to 4 h of extracorporeal ischemia at 4°C and 50 min of reperfusion at 37°C. The CE+S group received an intratracheal bolus of a modified natural bovine surfactant at a dosage of 50 mg/kg body weight before flush perfusion. After reperfusion (Celsior groups or immediately after sacrifice (Control, the lungs were fixed by vascular perfusion and processed for light and electron microscopy. Stereology was used to quantify edematous changes as well as alterations of the alveolar epithelial type II cells. Results Surfactant treatment decreased the intraalveolar edema formation (mean (coefficient of variation: CE: 160 mm3 (0.61 vs. CE+S: 4 mm3 (0.75; p 3 (0.90 vs. CE+S: 0 mm3; p 3 (0.39 vs. CE+S: 268 mm3 (0.43; p 3(0.10 and CE+S (481 μm3(0.10 compared with controls (323 μm3(0.07; p Conclusion Intratracheal surfactant application before I/R significantly reduces the intraalveolar edema formation and development of atelectases but leads to an increased development of

  19. Enolase 1 (ENO1 and protein disulfide-isomerase associated 3 (PDIA3 regulate Wnt/β-catenin-driven trans-differentiation of murine alveolar epithelial cells

    Directory of Open Access Journals (Sweden)

    Kathrin Mutze

    2015-08-01

    Full Text Available The alveolar epithelium represents a major site of tissue destruction during lung injury. It consists of alveolar epithelial type I (ATI and type II (ATII cells. ATII cells are capable of self-renewal and exert progenitor function for ATI cells upon alveolar epithelial injury. Cell differentiation pathways enabling this plasticity and allowing for proper repair, however, are poorly understood. Here, we applied proteomics, expression analysis and functional studies in primary murine ATII cells to identify proteins and molecular mechanisms involved in alveolar epithelial plasticity. Mass spectrometry of cultured ATII cells revealed a reduction of carbonyl reductase 2 (CBR2 and an increase in enolase 1 (ENO1 and protein disulfide-isomerase associated 3 (PDIA3 protein expression during ATII-to-ATI cell trans-differentiation. This was accompanied by increased Wnt/β-catenin signaling, as analyzed by qRT-PCR and immunoblotting. Notably, ENO1 and PDIA3, along with T1α (podoplanin; an ATI cell marker, exhibited decreased protein expression upon pharmacological and molecular Wnt/β-catenin inhibition in cultured ATII cells, whereas CBR2 levels were stabilized. Moreover, we analyzed primary ATII cells from mice with bleomycin-induced lung injury, a model exhibiting activated Wnt/β-catenin signaling in vivo. We observed reduced CBR2 significantly correlating with surfactant protein C (SFTPC, whereas ENO1 and PDIA3 along with T1α were increased in injured ATII cells. Finally, siRNA-mediated knockdown of ENO1, as well as PDIA3, in primary ATII cells led to reduced T1α expression, indicating diminished cell trans-differentiation. Our data thus identified proteins involved in ATII-to-ATI cell trans-differentiation and suggest a Wnt/β-catenin-driven functional role of ENO1 and PDIA3 in alveolar epithelial cell plasticity in lung injury and repair.

  20. Antibacterial activity and cell compatibility of TiZrN, TiZrCN, and TiZr-amorphous carbon coatings

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Heng-Li [School of Dentistry, China Medical University, Taichung 404, Taiwan (China); Department of Bioinformatics and Medical Engineering, Asia University, Taichung 41354, Taiwan (China); Chang, Yin-Yu, E-mail: yinyu@nfu.edu.tw [Department of Mechanical and Computer-aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Liu, Jia-Xu [Department of Mechanical and Computer-aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Tsai, Ming-Tzu [Department of Biomedical Engineering, Hungkuang University, Taichung 433, Taiwan (China); Lai, Chih-Ho [Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan (China)

    2015-12-01

    A cathodic-arc evaporation system with plasma-enhanced duct equipment was used to deposit TiZrN, TiZrCN, and TiZr/a-C coatings. Reactive gases (N{sub 2} and C{sub 2}H{sub 2}) activated by the Ti and Zr plasma in the evaporation process was used to deposit the TiZrCN and TiZr/a-C coatings with different C and nitrogen contents. The crystalline structures and bonding states of coatings were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. The microbial activity of the coatings was evaluated against Staphylococcus aureus (Gram-positive bacteria) and Actinobacillus actinomycetemcomitans (Gram-negative bacteria) by in vitro antibacterial analysis using a fluorescence staining method employing SYTO9 and a bacterial-viability test on an agar plate. The cell compatibility and morphology related to CCD-966SK cell-line human skin fibroblast cells on the coated samples were also determined using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, reverse-transcriptase-polymerase chain reaction, and scanning electron microscopy. The results suggest that the TiZrCN coatings not only possess better antibacterial performance than TiZrN and TiZr/a-C coatings but also maintain good compatibility with human skin fibroblast cells. - Highlights: • TiZrN, TiZrCN, and TiZr/a-C coatings were deposited using cathodic arc evaporation. • The TiZrCN showed a composite structure containing TiN, ZrN, and a-C. • The TiZrCN-coated Ti showed the least hydrophobicity among the samples. • The TiZrCN-coated Ti showed good human skin fibroblast cell viability. • The TiZrCN-coated Ti exhibited good antibacterial performance.

  1. Acute Exposure to Electronic and Combustible Cigarette Aerosols: Effects in an Animal Model and in Human Alveolar Cells.

    Science.gov (United States)

    Husari, Ahmad; Shihadeh, Alan; Talih, Soha; Hashem, Yasmine; El Sabban, Marwan; Zaatari, Ghazi

    2016-05-01

    Smoking electronic cigarettes (ECIG) is promoted as a safer alternative to smoking combustible cigarettes. This study investigates the effects of ECIG aerosol and cigarette smoke (CS) in an animal model and in human alveolar cell cultures (A549). Mice were divided into Control, ECIG, and CS. Animals were exposed for 6h/d to either lab air, ECIG or CS, for of 3 days. Total particulate matter exposure for the ECIG was set at higher levels compared to CS. Lung injury was determined by: (1) measurement of wet-to-dry ratio; (2) albumin concentration in the bronchoalveolar lavage fluid; (3) transcriptional expression of inflammatory mediators IL-1β, IL-6, TNF-α; (4) oxidative stress; (5) assessment of cell death; and (6) lung histopathology. Human alveolar cell cultures were treated with various concentrations of ECIG and CS aerosol extracts and the effects on cell proliferation were evaluated. Wet-to-dry ratio was higher in CS when compared to ECIG. Albumin leak in bronchoalveolar lavage fluid was evident in CS but not in ECIG. ECIG exposure was only associated with a significant increase in IL-1β. In contrast, CS exposure resulted in significant increases in IL-1β, IL-6, TNF-α expression, and oxidative stress. TUNEL staining demonstrated significant cell death in CS but not in ECIG. At the cellular level, ECIG and CS extracts reduced cell proliferation, however, CS exhibited effects at lower concentrations. Despite higher exposure conditions, ECIG exhibited less toxic effects on lungs of experimental animals and on A549 cell cultures when compared to CS. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Contribution of an alveolar cell of origin to the high-grade malignant phenotype of pregnancy-associated breast cancer.

    Science.gov (United States)

    Haricharan, S; Hein, S M; Dong, J; Toneff, M J; Aina, O H; Rao, P H; Cardiff, R D; Li, Y

    2014-12-11

    Pregnancy-associated breast cancers (PABCs) are tumors diagnosed during pregnancy or up to 5 years following parturition, and are usually high-grade, connective tissue-rich, and estrogen receptor (ER)/progesterone receptor-negative. Little is known about the cellular origin of PABCs or the mechanisms by which PABCs are initiated. Using the RCAS retrovirus to deliver the ErbB2 oncogene into the mammary epithelium of our previously reported MMTV-tva transgenic mice, we detected high-grade, poorly differentiated, stroma-rich and ER-negative tumors during pregnancy and lactation. These high-grade and stroma-rich tumors were less frequent in involuted mice or in age-matched nulliparous mice. More importantly, by generating a WAP-tva transgenic line for expression of ErbB2 selectively in WAP(+) mammary alveolar cells, we found that tumors had similar morphological phenotypes (high grade, poorly differentiated, stroma-rich and ER-negative), irrespective of the time since pregnancy and even in the absence of pregnancy. These data suggest that PABCs arise preferentially from an alveolar cell population that expands during pregnancy and lactation. This somatic mouse model may also be useful for preclinical testing of new prophylactic and therapeutic strategies against PABC.

  3. Contribution of an alveolar cell of origin to the aggressive phenotype of pregnancy-associated breast cancer

    Science.gov (United States)

    Haricharan, Svasti; Hein, Sarah; Dong, Jie; Toneff, Michael; Aina, Olulana; Rao, Pulivarthi H.; Cardiff, Robert; Li, Yi

    2014-01-01

    Pregnancy-associated breast cancers (PABCs) are malignancies diagnosed during pregnancy or up to five years following parturition, and are usually aggressive, stroma-rich, and estrogen receptor/progesterone receptor-negative; but little is known about the cellular origin of PABCs or the mechanisms by which PABCs initiate. Using the RCAS retrovirus to deliver the ErbB2 oncogene into the mammary epithelium of our previous reported MMTV-tva transgenic mice, we detected human PABC-like tumors during pregnancy and lactation but not in involuted mice or in age-matched virgin mice. More importantly, by generating a WAP-tva transgenic line for expression of ErbB2 selectively in WAP+ mammary alveolar cells, we found that the resulting tumors exhibited the hallmarks of PABCs irrespective of the time since pregnancy and even in the absence of pregnancy. These data suggest that PABCs arise preferentially from an alveolar cell population that expands during pregnancy and lactation. This somatic mouse model may also be useful for preclinical testing of new prophylactic and therapeutic strategies against PABC. PMID:24317513

  4. CXCL9 Regulates TGF-β1-Induced Epithelial to Mesenchymal Transition in Human Alveolar Epithelial Cells.

    Science.gov (United States)

    O'Beirne, Sarah L; Walsh, Sinead M; Fabre, Aurélie; Reviriego, Carlota; Worrell, Julie C; Counihan, Ian P; Lumsden, Robert V; Cramton-Barnes, Jennifer; Belperio, John A; Donnelly, Seamas C; Boylan, Denise; Marchal-Sommé, Joëlle; Kane, Rosemary; Keane, Michael P

    2015-09-15

    Epithelial to mesenchymal cell transition (EMT), whereby fully differentiated epithelial cells transition to a mesenchymal phenotype, has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). CXCR3 and its ligands are recognized to play a protective role in pulmonary fibrosis. In this study, we investigated the presence and extent of EMT and CXCR3 expression in human IPF surgical lung biopsies and assessed whether CXCR3 and its ligand CXCL9 modulate EMT in alveolar epithelial cells. Coexpression of the epithelial marker thyroid transcription factor-1 and the mesenchymal marker α-smooth muscle actin and CXCR3 expression was examined by immunohistochemical staining of IPF surgical lung biopsies. Epithelial and mesenchymal marker expression was examined by quantitative real-time PCR, Western blotting, and immunofluorescence in human alveolar epithelial (A549) cells treated with TGF-β1 and CXCL9, with Smad2, Smad3, and Smad7 expression and cellular localization examined by Western blotting. We found that significantly more cells were undergoing EMT in fibrotic versus normal areas of lung in IPF surgical lung biopsy samples. CXCR3 was expressed by type II pneumocytes and fibroblasts in fibrotic areas in close proximity to cells undergoing EMT. In vitro, CXCL9 abrogated TGF-β1-induced EMT. A decrease in TGF-β1-induced phosphorylation of Smad2 and Smad3 occurred with CXCL9 treatment. This was associated with increased shuttling of Smad7 from the nucleus to the cytoplasm where it inhibits Smad phosphorylation. This suggests a role for EMT in the pathogenesis of IPF and provides a novel mechanism for the inhibitory effects of CXCL9 on TGF-β1-induced EMT. Copyright © 2015 by The American Association of Immunologists, Inc.

  5. Porphyromonas gingivalis GroEL induces osteoclastogenesis of periodontal ligament cells and enhances alveolar bone resorption in rats.

    Directory of Open Access Journals (Sweden)

    Feng-Yen Lin

    Full Text Available Porphyromonas gingivalis is a major periodontal pathogen that contains a variety of virulence factors. The antibody titer to P. gingivalis GroEL, a homologue of HSP60, is significantly higher in periodontitis patients than in healthy control subjects, suggesting that P. gingivalis GroEL is a potential stimulator of periodontal disease. However, the specific role of GroEL in periodontal disease remains unclear. Here, we investigated the effect of P. gingivalis GroEL on human periodontal ligament (PDL cells in vitro, as well as its effect on alveolar bone resorption in rats in vivo. First, we found that stimulation of PDL cells with recombinant GroEL increased the secretion of the bone resorption-associated cytokines interleukin (IL-6 and IL-8, potentially via NF-κB activation. Furthermore, GroEL could effectively stimulate PDL cell migration, possibly through activation of integrin α1 and α2 mRNA expression as well as cytoskeletal reorganization. Additionally, GroEL may be involved in osteoclastogenesis via receptor activator of nuclear factor κ-B ligand (RANKL activation and alkaline phosphatase (ALP mRNA inhibition in PDL cells. Finally, we inoculated GroEL into rat gingiva, and the results of microcomputed tomography (micro-CT and histomorphometric assays indicated that the administration of GroEL significantly increased inflammation and bone loss. In conclusion, P. gingivalis GroEL may act as a potent virulence factor, contributing to osteoclastogenesis of PDL cells and resulting in periodontal disease with alveolar bone resorption.

  6. Cytotoxicity and inflammation in human alveolar epithelial cells following exposure to occupational levels of gold and silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bachand, George D., E-mail: gdbacha@sandia.gov [Sandia National Laboratories, Center for Integrated Nanotechnologies (United States); Allen, Amy [Sandia National Laboratories, Department of Analytical Science (United States); Bachand, Marlene [Sandia National Laboratories, Department of Nanobiology (United States); Achyuthan, Komandoor E. [Sandia National Laboratories, Department of Biosensors and Nanomaterials (United States); Seagrave, Jean Clare [Lovelace Respiratory Research Institute, Applied Life Science and Toxicology Division (United States); Brozik, Susan M. [Sandia National Laboratories, Department of Biosensors and Nanomaterials (United States)

    2012-10-15

    While inhalation represents one of the most likely routes of exposure, the toxicity and response of nanoparticles at concentrations expected from such an exposure are not well understood. Here we characterized the in vitro response of human A549 adenocarcinomic alveolar epithelial cells following exposure to gold (AuNP) and silver (AgNP) nanoparticles at levels approximating an occupational exposure. Changes in neither oxidative stress nor cytotoxicity were significantly affected by exposure to AgNPs and AuNPs, regardless of NP type (Ag vs. Au), concentration, surface ligand (citrate or tannic acid), or size. An inflammatory response was, however, observed in response to 20 nm AgNPs and 20 nm AuNPs, where significant differences in the release of interleukin (IL)-8 but not IL-6 were observed. Additional data demonstrated that increased IL-8 secretion was strongly dependent on both nanoparticle size and concentration. Overall these data suggest that, while not acutely toxic, occupational exposure to AuNPs and AgNPs may trigger a significant inflammatory response in alveolar epithelium. Moreover, the differential responses in IL-8 and IL-6 secretion suggest that NPs may induce a response pathway that is distinct from those commonly elicited by allergens and pathogens.

  7. Transplantation of osteoporotic bone marrow stromal cells rejuvenated by the overexpression of SATB2 prevents alveolar bone loss in ovariectomized rats.

    Science.gov (United States)

    Xu, Rongyao; Fu, Zongyun; Liu, Xue; Xiao, Tao; Zhang, Ping; Du, Yifei; Yuan, Hua; Cheng, Jie; Jiang, Hongbing

    2016-11-01

    Estrogen-deficient osteoporosis is an aging-related disease with high morbidity that not only significantly increases a woman's risk of fragility fracture but is also associated with tooth and bone loss in the supporting alveolar bone of the jaw. Emerging evidence suggests that the aging of bone marrow stromal cells (BMSCs) contributes to the development of osteoporosis. In this study, we aimed to investigate the role of the special AT-rich sequence-binding protein 2 (SATB2), a stemness and senescence regulator of craniofacial BMSCs, in rat ovariectomy-induced alveolar osteoporosis. We also sought to determine whether transplantation of SATB2-modified BMSCs could ameliorate estrogen deficient alveolar bone loss. Our data revealed that BMSCs from ovariectomy-induced alveolar bone exhibited typical senescence phenotypes such as diminished stemness and osteogenic capacity, increased expression of senescence or osteoclastic markers and enhanced adipogenic potential. These phenotypic changes are a result of SATB2-mediated senescence dysregulation as evidenced by nuclear γH2AX foci formation. Moreover, overexpression of SATB2 significantly alleviated the senescence of osteoporotic BMSCs in vitro. Importantly, transplantation of SATB2-modified BMSCs significantly attenuated ovariectomy-induced alveolar bone loss in vivo. Together, our results revealed that SATB2 is a critical regulator of alveolar BMSC senescence, and its overexpression decreases these senescent changes both in vitro and in vivo. SATB2-modified BMSC delivery could be a viable and promising therapeutic strategy for alveolar bone loss induced by estrogen-deficient osteoporosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. B cell, CD8 + T cell and gamma delta T cell infiltration alters alveolar immune cell homeostasis in HIV-infected Malawian adults [version 2; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    Andrew Mwale

    2017-12-01

    Full Text Available Background: HIV infection is associated with increased risk to lower respiratory tract infections (LRTI. However, the impact of HIV infection on immune cell populations in the lung is not well defined. We sought to comprehensively characterise the impact of HIV infection on immune cell populations in the lung. Methods: Twenty HIV-uninfected controls and 17 HIV-1 infected ART-naïve adults were recruited from Queen Elizabeth Central Hospital, Malawi. Immunophenotyping of lymphocyte and myeloid cell populations was done on bronchoalveolar lavage fluid and peripheral blood cells. Results: We found that the numbers of CD8 + T cells, B cells and gamma delta T cells were higher in BAL fluid of HIV-infected adults compared to HIV-uninfected controls (all p<0.05. In contrast, there was no difference in the numbers of alveolar CD4 + T cells in HIV-infected adults compared to HIV-uninfected controls (p=0.7065. Intermediate monocytes were the predominant monocyte subset in BAL fluid (HIV-, 63%; HIV+ 81%, while the numbers of classical monocytes was lower in HIV-infected individuals compared to HIV-uninfected adults (1 × 10 5 vs. 2.8 × 10 5 cells/100ml of BAL fluid, p=0.0001. The proportions of alveolar macrophages and myeloid dendritic cells was lower in HIV-infected adults compared to HIV-uninfected controls (all p<0.05. Conclusions: Chronic HIV infection is associated with broad alteration of immune cell populations in the lung, but does not lead to massive depletion of alveolar CD4 + T cells. Disruption of alveolar immune cell homeostasis likely explains in part the susceptibility for LRTIs in HIV-infected adults.

  9. Role of alveolar epithelial Early growth response-1 (Egr-1) in CD8+ T Cell mediated Lung Injury

    Science.gov (United States)

    Ramana, Chilakamarti V.; Cheng, Guang-Shing; Kumar, Aseem; Kwon, Hyung- Joo; Enelow, Richard I.

    2009-01-01

    Influenza infection of the distal airways results in severe lung injury, a considerable portion of which is immunopathologic and attributable to the host responses. We have used a mouse model to specifically investigate the role of antiviral CD8+ T cells in this injury, and have found that the critical effector molecule is TNF-α expressed by the T cells upon antigen recognition. Interestingly, the immunopathology which ensues is characterized by significant accumulation of host inflammatory cells, recruited by chemokines expressed by the target alveolar epithelial cells. In this study we analyzed the mechanisms involved in the induction of epithelial chemokine expression triggered by antigen-specific CD8+ T cell recognition, and demonstrate that the Early growth response-1 (Egr-1) transcription factor is rapidly induced in epithelial cells, both in vitro and ex vivo, and that this is a critical regulator of a host of inflammatory chemokines. Genetic deficiency of Egr-1 significantly abrogates both the chemokine expression and the immunopathologic injury associated with T cell recognition, and it directly regulates transcriptional activity of a model CXC chemokine, MIP-2. We further demonstrate that Egr-1 induction is triggered by TNF-α– dependent ERK activation, and inhibition of this pathway ablates Egr-1 expression. These findings suggest that Egr-1 may represent an important target in mitigating the immunopathology of severe influenza infection. PMID:19786304

  10. Role of alveolar epithelial early growth response-1 (Egr-1) in CD8+ T cell-mediated lung injury.

    Science.gov (United States)

    Ramana, Chilakamarti V; Cheng, Guang-Shing; Kumar, Aseem; Kwon, Hyung-Joo; Enelow, Richard I

    2009-12-01

    Influenza infection of the distal airways results in severe lung injury, a considerable portion of which is immunopathologic and attributable to the host responses. We have used a mouse model to specifically investigate the role of antiviral CD8(+) T cells in this injury, and have found that the critical effector molecule is TNF-alpha expressed by the T cells upon antigen recognition. Interestingly, the immunopathology which ensues is characterized by significant accumulation of host inflammatory cells, recruited by chemokines expressed by the target alveolar epithelial cells. In this study we analyzed the mechanisms involved in the induction of epithelial chemokine expression triggered by antigen-specific CD8(+) T cell recognition, and demonstrate that the early growth response-1 (Egr-1) transcription factor is rapidly induced in epithelial cells, both in vitro and ex vivo, and that this is a critical regulator of a host of inflammatory chemokines. Genetic deficiency of Egr-1 significantly abrogates both the chemokine expression and the immunopathologic injury associated with T cell recognition, and it directly regulates transcriptional activity of a model CXC chemokine, MIP-2. We further demonstrate that Egr-1 induction is triggered by TNF-alpha-dependent ERK activation, and inhibition of this pathway ablates Egr-1 expression. These findings suggest that Egr-1 may represent an important target in mitigating the immunopathology of severe influenza infection.

  11. Human decidua-derived mesenchymal stem cells differentiate into functional alveolar type II-like cells that synthesize and secrete pulmonary surfactant complexes.

    Directory of Open Access Journals (Sweden)

    Alejandro Cerrada

    Full Text Available Lung alveolar type II (ATII cells are specialized in the synthesis and secretion of pulmonary surfactant, a lipid-protein complex that reduces surface tension to minimize the work of breathing. Surfactant synthesis, assembly and secretion are closely regulated and its impairment is associated with severe respiratory disorders. At present, well-established ATII cell culture models are not available. In this work, Decidua-derived Mesenchymal Stem Cells (DMSCs have been differentiated into Alveolar Type II- Like Cells (ATII-LCs, which display membranous cytoplasmic organelles resembling lamellar bodies, the organelles involved in surfactant storage and secretion by native ATII cells, and accumulate disaturated phospholipid species, a surfactant hallmark. Expression of characteristic ATII cells markers was demonstrated in ATII-LCs at gene and protein level. Mimicking the response of ATII cells to secretagogues, ATII-LCs were able to exocytose lipid-rich assemblies, which displayed highly surface active capabilities, including faster interfacial adsorption kinetics than standard native surfactant, even in the presence of inhibitory agents. ATII-LCs could constitute a highly useful ex vivo model for the study of surfactant biogenesis and the mechanisms involved in protein processing and lipid trafficking, as well as the packing and storage of surfactant complexes.

  12. Intrauterine growth restriction decreases pulmonary alveolar and vessel growth and causes pulmonary artery endothelial cell dysfunction in vitro in fetal sheep

    Science.gov (United States)

    Seedorf, Gregory J.; Brown, Alicia; Roe, Gates; O'Meara, Meghan C.; Gien, Jason; Tang, Jen-Ruey; Abman, Steven H.

    2011-01-01

    Intrauterine growth restriction (IUGR) increases the risk for bronchopulmonary dysplasia (BPD). Abnormal lung structure has been noted in animal models of IUGR, but whether IUGR adversely impacts fetal pulmonary vascular development and pulmonary artery endothelial cell (PAEC) function is unknown. We hypothesized that IUGR would decrease fetal pulmonary alveolarization, vascular growth, and in vitro PAEC function. Studies were performed in an established model of severe placental insufficiency and IUGR induced by exposing pregnant sheep to elevated temperatures. Alveolarization, quantified by radial alveolar counts, was decreased 20% (P growth by 68% (P growth was reduced in IUGR PAECs by 29% at baseline (P growth and PAEC dysfunction in vitro. This may contribute to the increased risk for adverse respiratory outcomes and BPD in infants with IUGR. PMID:21873446

  13. Dual role for plasminogen activator inhibitor type 1 as soluble and as matricellular regulator of epithelial alveolar cell wound healing.

    Science.gov (United States)

    Maquerlot, François; Galiacy, Stephane; Malo, Michel; Guignabert, Christophe; Lawrence, Daniel A; d'Ortho, Maria-Pia; Barlovatz-Meimon, Georgia

    2006-11-01

    Epithelium repair, crucial for restoration of alveolo-capillary barrier integrity, is orchestrated by various cytokines and growth factors. Among them keratinocyte growth factor plays a pivotal role in both cell proliferation and migration. The urokinase plasminogen activator (uPA) system also influences cell migration through proteolysis during epithelial repair. In addition, the complex formed by uPAR-uPA and matrix-bound plasminogen activator inhibitor type-1 (PAI-1) exerts nonproteolytic roles in various cell types. Here we present new evidence about the dual role of PAI-1 under keratinocyte growth factor stimulation using an in vitro repair model of rat alveolar epithelial cells. Besides proteolytic involvement of the uPA system, the availability of matrix-bound-PAI-1 is also required for an efficient healing. An unexpected decrease of healing was shown when PAI-1 activity was blocked. However, the proteolytic action of uPA and plasmin were still required. Moreover, immediately after wounding, PAI-1 was dramatically increased in the newly deposited matrix at the leading edge of wounds. We thus propose a dual role for PAI-1 in epithelial cell wound healing, both as a soluble inhibitor of proteolysis and also as a matrix-bound regulator of cell migration. Matrix-bound PAI-1 could thus be considered as a new member of the matricellular protein family.

  14. A rare case of sarcoid-like reaction of lymph nodes associated with squamous cell carcinoma of alveolar mucosa

    Directory of Open Access Journals (Sweden)

    Nag Shweta

    2009-01-01

    Full Text Available Non-necrotizing granulomas are occasionally seen in patients with certain malignant disorders and are termed as "sarcoid-like reaction," which have many similarities with sarcoidosis. Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by organ involvement and interference of organ function by granuloma or fibrosis. Sarcoidosis is occasionally found in a variety of malignant diseases with an overall incidence of 4.4% in carcinoma patients. We present here a rare case of moderately differentiated squamous cell carcinoma of alveolar mucosa with regard to mandible associated with sarcoid-like reaction of cervical lymph nodes in a female patient in the absence of clinical evidence of systemic sarcoidosis. The relevant literature including pathogenesis is also discussed.

  15. Balance of life and death in alveolar epithelial type II cells: proliferation, apoptosis, and the effects of cyclic stretch on wound healing.

    Science.gov (United States)

    Crosby, Lynn M; Luellen, Charlean; Zhang, Zhihong; Tague, Larry L; Sinclair, Scott E; Waters, Christopher M

    2011-10-01

    After acute lung injury, repair of the alveolar epithelium occurs on a substrate undergoing cyclic mechanical deformation. While previous studies showed that mechanical stretch increased alveolar epithelial cell necrosis and apoptosis, the impact of cell death during repair was not determined. We examined epithelial repair during cyclic stretch (CS) in a scratch-wound model of primary rat alveolar type II (ATII) cells and found that CS altered the balance between proliferation and cell death. We measured cell migration, size, and density; intercellular gap formation; cell number, proliferation, and apoptosis; cytoskeletal organization; and focal adhesions in response to scratch wounding followed by CS for up to 24 h. Under static conditions, wounds were closed by 24 h, but repair was inhibited by CS. Wounding stimulated cell motility and proliferation, actin and vinculin redistribution, and focal adhesion formation at the wound edge, while CS impeded cell spreading, initiated apoptosis, stimulated cytoskeletal reorganization, and attenuated focal adhesion formation. CS also caused significant intercellular gap formation compared with static cells. Our results suggest that CS alters several mechanisms of epithelial repair and that an imbalance occurs between cell death and proliferation that must be overcome to restore the epithelial barrier.

  16. Effects of β-Glucans Ingestion on Alveolar Bone Loss, Intestinal Morphology, Systemic Inflammatory Profile, and Pancreatic β-Cell Function in Rats with Periodontitis and Diabetes

    Science.gov (United States)

    Silva, Viviam de O.; Lobato, Raquel V.; Orlando, Débora R.; Borges, Bruno D.B.; de Sousa, Raimundo V.

    2017-01-01

    This study aimed to evaluate the effects of β-glucan ingestion (Saccharomyces cerevisiae) on the plasmatic levels of tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10), alveolar bone loss, and pancreatic β-cell function (HOMA-BF) in diabetic rats with periodontal disease (PD). Besides, intestinal morphology was determined by the villus/crypt ratio. A total of 48 Wistar rats weighing 203 ± 18 g were used. Diabetes was induced by the intraperitoneal injection of streptozotocin (80 mg/kg) and periodontal inflammation, by ligature. The design was completely randomized in a factorial scheme 2 × 2 × 2 (diabetic or not, with or without periodontitis, and ingesting β-glucan or not). The animals received β-glucan by gavage for 28 days. Alveolar bone loss was determined by scanning electron microscopy (distance between the cementoenamel junction and alveolar bone crest) and histometric analysis (bone area between tooth roots). β-glucan reduced plasmatic levels of TNF-α in diabetic animals with PD and of IL-10 in animals with PD (p < 0.05). β-glucan reduced bone loss in animals with PD (p < 0.05). In diabetic animals, β-glucan improved β-cell function (p < 0.05). Diabetic animals had a higher villus/crypt ratio (p < 0.05). In conclusion, β-glucan ingestion reduced the systemic inflammatory profile, prevented alveolar bone loss, and improved β-cell function in diabetic animals with PD. PMID:28906456

  17. Environmental particulate (PM2.5 augments stiffness-induced alveolar epithelial cell mechanoactivation of transforming growth factor beta.

    Directory of Open Access Journals (Sweden)

    Marilyn M Dysart

    Full Text Available Dysfunctional pulmonary homeostasis and repair, including diseases such as pulmonary fibrosis (PF, chronic obstructive pulmonary disease (COPD, and tumorigenesis have been increasing over the past decade, a fact that heavily implicates environmental influences. Several investigations have suggested that in response to increased transforming growth factor--beta (TGFβ signaling, the alveolar type II (ATII epithelial cell undergoes phenotypic changes that may contribute to the complex pathobiology of PF. We have previously demonstrated that increased tissue stiffness associated with PF is a potent extracellular matrix (ECM signal for epithelial cell activation of TGFβ. The work reported here explores the relationship between tissue stiffness and exposure to environmental stimuli in the activation of TGFβ. We hypothesized that exposure of ATII cells to fine particulate matter (PM2.5 will result in enhanced cell contractility, TGFβ activation, and subsequent changes to ATII cell phenotype. ATII cells were cultured on increasingly stiff substrates with or without addition of PM2.5. Exposure to PM2.5 resulted in increased activation of TGFβ, increased cell contractility, and elongation of ATII cells. Most notably, on 8 kPa substrates, a stiffness greater than normal but less than established fibrotic lung, addition of PM2.5 resulted in increased cortical cell stiffness, enhanced actin staining and cell elongation; a result not seen in the absence of PM2.5. Our work suggests that PM2.5 exposure additionally enhances the existing interaction between ECM stiffness and TGFβ that has been previously reported. Furthermore, we show that this additional enhancement is likely a consequence of intracellular reactive oxygen species (ROS leading to increased TGFβ signaling events. These results highlight the importance of both the micromechanical and biochemical environment in lung disease initiation and suggest that individuals in early stages of lung

  18. Wnt-inducible protein (WISP-1 is a key regulator of alveolar epithelial cell hyperplasia in pulmonary fibrosis

    Directory of Open Access Journals (Sweden)

    Melanie Königshoff

    2006-12-01

    Full Text Available Fibrotic lung disease is characterized by distorted lung architecture and severe loss of respiratory function secondary to alveolar epithelial cell (AEC hyperplasia, enhanced extracellular matrix (ECM deposition and fibroblast proliferation. Repetitive epithelial injuries with impaired alveolar wound healing and altered AEC gene expression represent a trigger mechanism for development of fibrosis. To reveal gene regulatory networks in lung fibrosis, we compared gene expression profiles of freshly isolated AEC obtained from mice 14 days after saline or bleomycin (BM instillation using whole genome microarray analysis. Several genes of the Wnt signaling pathway, in particular WISP-1, a member of the CCN family, were highly regulated. WISP-1 protein expression was demonstrated in proliferating AEC in BM-treated lungs by immunofluorescence. When analyzing all six CCN family members, WISP-1 was upregulated the most 14 days after BM challenge, as analyzed by qRT-PCR. To elucidate WISP-1 function, cultured primary mouse AEC were stimulated with WISP-1 and demonstrated a 230% increase in proliferation, analyzed by 3H-thymidine incorporation. This was mediated through enhanced phosphorylation, but not expression of protein kinase B (PKB/Akt, as detected by immunoblot. Finally, increased expression of WISP-1 was detected in lung homogenates and isolated AEC from IPF patients, using qRT-PCR. Immunohistochemical analysis of WISP-1 and Ki67 verified the existence of hyperplastic and proliferative AEC expressing WISP-1 in vivo. Our study thus identifies WISP-1 as a novel regulator of AEC injury and repair, and suggests that WISP-1 is a key mediator in pulmonary fibrosis.

  19. CCR2 and CXCR3 agonistic chemokines are differently expressed and regulated in human alveolar epithelial cells type II

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    Prasse Antje

    2005-07-01

    Full Text Available Abstract The attraction of leukocytes from circulation to inflamed lungs depends on the activation of both the leukocytes and the resident cells within the lung. In this study we determined gene expression and secretion patterns for monocyte chemoattractant protein-1 (MCP-1/CCL2 and T-cell specific CXCR3 agonistic chemokines (Mig/CXCL9, IP-10/CXCL10, and I-TAC/CXCL11 in TNF-α-, IFN-γ-, and IL-1β-stimulated human alveolar epithelial cells type II (AEC-II. AEC-II constitutively expressed high level of CCL2 mRNA in vitro and in situ , and released CCL2 protein in vitro . Treatment of AEC-II with proinflammatory cytokines up-regulated both CCL2 mRNA expression and release of immunoreactive CCL2, whereas IFN-γ had no effect on CCL2 release. In contrast, CXCR3 agonistic chemokines were not detected in freshly isolated AEC-II or in non-stimulated epithelial like cell line A549. IFN-γ, alone or in combination with IL-1β and TNF-α resulted in an increase in CXCL10, CXCL11, and CXCL9 mRNA expression and generation of CXCL10 protein by AEC-II or A549 cells. CXCL10 gene expression and secretion were induced in dose-dependent manner after cytokine-stimulation of AEC-II with an order of potency IFN-γ>>IL-1β ≥ TNF-α. Additionally, we localized the CCL2 and CXCL10 mRNAs in human lung tissue explants by in situ hybridization, and demonstrated the selective effects of cytokines and dexamethasone on CCL2 and CXCL10 expression. These data suggest that the regulation of the CCL2 and CXCL10 expression exhibit significant differences in their mechanisms, and also demonstrate that the alveolar epithelium contributes to the cytokine milieu of the lung, with the ability to respond to locally generated cytokines and to produce potent mediators of the local inflammatory response.

  20. Rhizoma Dioscoreae extract protects against alveolar bone loss by regulating the cell cycle: A predictive study based on the protein‑protein interaction network.

    Science.gov (United States)

    Zhang, Zhi-Guo; Song, Chang-Heng; Zhang, Fang-Zhen; Chen, Yan-Jing; Xiang, Li-Hua; Xiao, Gary Guishan; Ju, Da-Hong

    2016-06-01

    Rhizoma Dioscoreae extract (RDE) exhibits a protective effect on alveolar bone loss in ovariectomized (OVX) rats. The aim of this study was to predict the pathways or targets that are regulated by RDE, by re‑assessing our previously reported data and conducting a protein‑protein interaction (PPI) network analysis. In total, 383 differentially expressed genes (≥3‑fold) between alveolar bone samples from the RDE and OVX group rats were identified, and a PPI network was constructed based on these genes. Furthermore, four molecular clusters (A‑D) in the PPI network with the smallest P‑values were detected by molecular complex detection (MCODE) algorithm. Using Database for Annotation, Visualization and Integrated Discovery (DAVID) and Ingenuity Pathway Analysis (IPA) tools, two molecular clusters (A and B) were enriched for biological process in Gene Ontology (GO). Only cluster A was associated with biological pathways in the IPA database. GO and pathway analysis results showed that cluster A, associated with cell cycle regulation, was the most important molecular cluster in the PPI network. In addition, cyclin‑dependent kinase 1 (CDK1) may be a key molecule achieving the cell‑cycle‑regulatory function of cluster A. From the PPI network analysis, it was predicted that delayed cell cycle progression in excessive alveolar bone remodeling via downregulation of CDK1 may be another mechanism underling the anti‑osteopenic effect of RDE on alveolar bone.

  1. Evaluation of amniotic mesenchymal cell derivatives on cytokine production in equine alveolar macrophages: an in vitro approach to lung inflammation.

    Science.gov (United States)

    Zucca, Enrica; Corsini, Emanuela; Galbiati, Valentina; Lange-Consiglio, Anna; Ferrucci, Francesco

    2016-09-20

    Data obtained in both animal models and clinical trials suggest that cell-based therapies represent a potential therapeutic strategy for lung repair and remodeling. Recently, new therapeutic approaches based on the use of stem cell derivatives (e.g., conditioned medium (CM) and microvesicles (MVs)) to regenerate tissues and improve their functions were proposed. The aim of this study was to investigate the immunomodulatory effects of equine amniotic mesenchymal cell derivatives on lipopolysaccharide (LPS)-induced cytokine production in equine alveolar macrophages, which may be beneficial in lung inflammatory disorders such as recurrent airway obstruction (RAO) in horses. RAO shares many features with human asthma, including an increased number of cells expressing mRNA for interleukin (IL)-4 and IL-5 and a decreased expression of IFN-γ in bronchoalveolar lavage fluid (BALF) of affected horses. The release of TNF-α, IL-6, and TGF-β1 at different time points (1, 24, 48, and 72 h) was measured in equine alveolar macrophages stimulated or not with LPS (10 and 100 ng/mL) in the presence or absence of 10 % CM or 50 × 10(6) MVs/mL. Cytokines were measured using commercially available ELISA kits. For multiple comparisons, analysis of variance was used with Tukey post-hoc test. Differences were considered significant at p ≤ 0.05. Significant modulatory effects of CM on LPS-induced TNF-α release at 24 h, and of both CM and MVs on TNF-α release at 48 h were observed. A trend toward a modulatory effect of both CM and MVs on the release of TGF-β and possibly IL-6 was visible over time. Results support the potential use of CM and MVs in lung regenerative medicine, especially in situations in which TGF-β may be detrimental, such as respiratory allergy. Further studies should evaluate the potential clinical applications of CM and MVs in equine lung diseases, such as RAO and other inflammatory disorders.

  2. Cooperativity between CD8+ T cells, non-neutralizing antibodies, and alveolar macrophages is important for heterosubtypic influenza virus immunity.

    Directory of Open Access Journals (Sweden)

    Brian J Laidlaw

    2013-03-01

    Full Text Available Seasonal epidemics of influenza virus result in ∼36,000 deaths annually in the United States. Current vaccines against influenza virus elicit an antibody response specific for the envelope glycoproteins. However, high mutation rates result in the emergence of new viral serotypes, which elude neutralization by preexisting antibodies. T lymphocytes have been reported to be capable of mediating heterosubtypic protection through recognition of internal, more conserved, influenza virus proteins. Here, we demonstrate using a recombinant influenza virus expressing the LCMV GP33-41 epitope that influenza virus-specific CD8+ T cells and virus-specific non-neutralizing antibodies each are relatively ineffective at conferring heterosubtypic protective immunity alone. However, when combined virus-specific CD8 T cells and non-neutralizing antibodies cooperatively elicit robust protective immunity. This synergistic improvement in protective immunity is dependent, at least in part, on alveolar macrophages and/or other lung phagocytes. Overall, our studies suggest that an influenza vaccine capable of eliciting both CD8+ T cells and antibodies specific for highly conserved influenza proteins may be able to provide heterosubtypic protection in humans, and act as the basis for a potential "universal" vaccine.

  3. Effects of PPARγ ligands on TGF-β1-induced epithelial-mesenchymal transition in alveolar epithelial cells

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    Dagher Hayat

    2010-02-01

    Full Text Available Abstract Background Transforming growth factor β1 (TGF-β1-mediated epithelial mesenchymal transition (EMT of alveolar epithelial cells (AEC may contribute to lung fibrosis. Since PPARγ ligands have been shown to inhibit fibroblast activation by TGF-β1, we assessed the ability of the thiazolidinediones rosiglitazone (RGZ and ciglitazone (CGZ to regulate TGF-β1-mediated EMT of A549 cells, assessing changes in cell morphology, and expression of cell adhesion molecules E-cadherin (epithelial cell marker and N-cadherin (mesenchymal cell marker, and collagen 1α1 (COL1A1, CTGF and MMP-2 mRNA. Methods Serum-deprived A549 cells (human AEC cell line were pre-incubated with RGZ and CGZ (1 - 30 μM in the absence or presence of the PPARγ antagonist GW9662 (10 μM before TGFβ-1 (0.075-7.5 ng/ml treatment for up to 72 hrs. Changes in E-cadherin, N-cadherin and phosphorylated Smad2 and Smad3 levels were analysed by Western blot, and changes in mRNA levels including COL1A1 assessed by RT-PCR. Results TGFβ-1 (2.5 ng/ml-induced reductions in E-cadherin expression were associated with a loss of epithelial morphology and cell-cell contact. Concomitant increases in N-cadherin, MMP-2, CTGF and COL1A1 were evident in predominantly elongated fibroblast-like cells. Neither RGZ nor CGZ prevented TGFβ1-induced changes in cell morphology, and PPARγ-dependent inhibitory effects of both ligands on changes in E-cadherin were only evident at submaximal TGF-β1 (0.25 ng/ml. However, both RGZ and CGZ inhibited the marked elevation of N-cadherin and COL1A1 induced by TGF-β1 (2.5 ng/ml, with effects on COL1A1 prevented by GW9662. Phosphorylation of Smad2 and Smad3 by TGF-β1 was not inhibited by RGZ or CGZ. Conclusions RGZ and CGZ inhibited profibrotic changes in TGF-β1-stimulated A549 cells independently of inhibition of Smad phosphorylation. Their inhibitory effects on changes in collagen I and E-cadherin, but not N-cadherin or CTGF, appeared to be PPAR

  4. Titanium carbide and its core-shelled derivative TiC-TiO2 as catalyst supports for proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Ignaszak, Anna; Song, Chaojie; Zhu, Weimin; Zhang, Jiujun; Bauer, Alex; Baker, Ryan; Neburchilov, Vladimir; Ye, Siyu; Campbell, Stephen

    2012-01-01

    Both TiC and core-shelled TiC-TiO 2 are investigated as catalyst supports for proton exchange membrane fuel cells (PEMFCs). TiC is thermally stable, possesses both low solubility in sulphuric acid and high electronic conductivity. However, TiC undergoes irreversible electrochemical oxidation in dilute perchloric acid and the operating potential range of 0–1.2 V RHE . TiC-TiO 2 core–shell composite is found to be more stable than TiC. Both these materials are used as supports for Pt and Pt–Pd alloy catalysts (Pt/TiC, Pt 3 Pd/TiC and Pt 3 Pd/TiC-TiO 2 ) and are synthesized by microwave-assisted polyol process. The catalytic activities of both Pt 3 Pd/TiC and Pt 3 Pd/TiC-TiO 2 toward the oxygen reduction reaction (ORR) are much higher than those for Pt/TiC. Accelerated durability tests show that TiC supported catalysts are not electrochemically stable. The corresponding TiC-TiO 2 supported catalyst is more stable than that supported by TiC, indicating that with a protective oxide layer on the TiC core, TiC-TiO 2 is a promising PEMFC catalyst support.

  5. Effect of substratum, serum and linoleic acid on the lipid synthesis of isolated alveolar type II cells

    International Nuclear Information System (INIS)

    Cott, G.R.; Edeen, K.E.; Hale, S.G.; Mason, R.J.

    1986-01-01

    The authors examined the effect of cellular substratum (plastic or amnionic basement membrane (ABM)) and serum additive (fetal bovine (FBS), pork, horse, rat or human) on phospholipid synthesis in alveolar type II cells. The cells were isolated from adult rats, cultured for 48 hours under the various substratum and serum conditions, and then incubated for an additional 2 hours with [1- 14 C] acetate. ABM consistently caused a significant increase in the percent of radiolabel incorporated into phosphatidylcholine (PC) and/or phosphatidylglycerol (PG). Serum also had a significant effect with the highest values of PC and saturated PC being obtained with rat serum and the highest PG values with horse serum. The fatty acid composition of the sera used varied according to species with the largest variations in percent linoleic acid. Supplementing media with linoleic acid resulted in a marked increase in saturated PC values and a fall in PG values. Therefore, they conclude that: 1) ABM improves differentiated function, 2) FBS supplementation may not be optimal, and 3) the different effects of linoleic acid supplementation on PC, saturated PC, and PG values suggests an independent regulation of synthesis for these lipid species in vitro

  6. Exposure to Bordetella pertussis adenylate cyclase toxin affects integrin-mediated adhesion and mechanics in alveolar epithelial cells.

    Science.gov (United States)

    Angely, Christelle; Nguyen, Ngoc-Minh; Andre Dias, Sofia; Planus, Emmanuelle; Pelle, Gabriel; Louis, Bruno; Filoche, Marcel; Chenal, Alexandre; Ladant, Daniel; Isabey, Daniel

    2017-08-01

    The adenylate cyclase (CyaA) toxin is a major virulent factor of Bordetella pertussis, the causative agent of whooping cough. CyaA toxin is able to invade eukaryotic cells where it produces high levels of cyclic adenosine monophosphate (cAMP) affecting cellular physiology. Whether CyaA toxin can modulate cell matrix adhesion and mechanics of infected cells remains largely unknown. In this study, we use a recently proposed multiple bond force spectroscopy (MFS) with an atomic force microscope to assess the early phase of cell adhesion (maximal detachment and local rupture forces) and cell rigidity (Young's modulus) in alveolar epithelial cells (A549) for toxin exposure 95%) at CyaA concentration of 0.5 nM, but a significant effect (≈81%) at 10 nM. MFS performed on A549 for three different concentrations (0.5, 5 and 10 nM) demonstrates that CyaA toxin significantly affects both cell adhesion (detachment forces are decreased) and cell mechanics (Young's modulus is increased). CyaA toxin (at 0.5 nM) assessed at three indentation/retraction speeds (2, 5 and 10 μm/s) significantly affects global detachment forces, local rupture events and Young modulus compared with control conditions, while an enzymatically inactive variant CyaAE5 has no effect. These results reveal the loading rate dependence of the multiple bonds newly formed between the cell and integrin-specific coated probe as well as the individual bond kinetics which are only slightly affected by the patho-physiological dose of CyaA toxin. Finally, theory of multiple bond force rupture enables us to deduce the bond number N which is reduced by a factor of 2 upon CyaA exposure (N ≈ 6 versus N ≈ 12 in control conditions). MFS measurements demonstrate that adhesion and mechanical properties of A549 are deeply affected by exposure to the CyaA toxin but not to an enzymatically inactive variant. This indicates that the alteration of cell mechanics triggered by CyaA is a consequence of the increase in

  7. Differential cell reaction upon Toll-like receptor 4 and 9 activation in human alveolar and lung interstitial macrophages

    Directory of Open Access Journals (Sweden)

    Meyerhans Andreas

    2010-09-01

    Full Text Available Abstract Background Investigations on pulmonary macrophages (MΦ mostly focus on alveolar MΦ (AM as a well-defined cell population. Characteristics of MΦ in the interstitium, referred to as lung interstitial MΦ (IM, are rather ill-defined. In this study we therefore aimed to elucidate differences between AM and IM obtained from human lung tissue. Methods Human AM and IM were isolated from human non-tumor lung tissue from patients undergoing lung resection. Cell morphology was visualized using either light, electron or confocal microscopy. Phagocytic activity was analyzed by flow cytometry as well as confocal microscopy. Surface marker expression was measured by flow cytometry. Toll-like receptor (TLR expression patterns as well as cytokine expression upon TLR4 or TLR9 stimulation were assessed by real time RT-PCR and cytokine protein production was measured using a fluorescent bead-based immunoassay. Results IM were found to be smaller and morphologically more heterogeneous than AM, whereas phagocytic activity was similar in both cell types. HLA-DR expression was markedly higher in IM compared to AM. Although analysis of TLR expression profiles revealed no differences between the two cell populations, AM and IM clearly varied in cell reaction upon activation. Both MΦ populations were markedly activated by LPS as well as DNA isolated from attenuated mycobacterial strains (M. bovis H37Ra and BCG. Whereas AM expressed higher amounts of inflammatory cytokines upon activation, IM were more efficient in producing immunoregulatory cytokines, such as IL10, IL1ra, and IL6. Conclusion AM appear to be more effective as a non-specific first line of defence against inhaled pathogens, whereas IM show a more pronounced regulatory function. These dissimilarities should be taken into consideration in future studies on the role of human lung MΦ in the inflammatory response.

  8. Small airway epithelial cells exposure to printer-emitted engineered nanoparticles induces cellular effects on human microvascular endothelial cells in an alveolar-capillary co-culture model.

    Science.gov (United States)

    Sisler, Jennifer D; Pirela, Sandra V; Friend, Sherri; Farcas, Mariana; Schwegler-Berry, Diane; Shvedova, Anna; Castranova, Vincent; Demokritou, Philip; Qian, Yong

    2015-01-01

    The printer is one of the most common office equipment. Recently, it was reported that toner formulations for printing equipment constitute nano-enabled products (NEPs) and contain engineered nanomaterials (ENMs) that become airborne during printing. To date, insufficient research has been performed to understand the potential toxicological properties of printer-emitted particles (PEPs) with several studies using bulk toner particles as test particles. These studies demonstrated the ability of toner particles to cause chronic inflammation and fibrosis in animal models. However, the toxicological implications of inhalation exposures to ENMs emitted from laser printing equipment remain largely unknown. The present study investigates the toxicological effects of PEPs using an in vitro alveolar-capillary co-culture model with Human Small Airway Epithelial Cells (SAEC) and Human Microvascular Endothelial Cells (HMVEC). Our data demonstrate that direct exposure of SAEC to low concentrations of PEPs (0.5 and 1.0 µg/mL) caused morphological changes of actin remodeling and gap formations within the endothelial monolayer. Furthermore, increased production of reactive oxygen species (ROS) and angiogenesis were observed in the HMVEC. Analysis of cytokine and chemokine levels demonstrates that interleukin (IL)-6 and MCP-1 may play a major role in the cellular communication observed between SAEC and HMVEC and the resultant responses in HMVEC. These data indicate that PEPs at low, non-cytotoxic exposure levels are bioactive and affect cellular responses in an alveolar-capillary co-culture model, which raises concerns for potential adverse health effects.

  9. Mesenchymal Stem Cell Conditioned Medium Promotes Proliferation and Migration of Alveolar Epithelial Cells under Septic Conditions In Vitro via the JNK-P38 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Jie Chen

    2015-11-01

    Full Text Available Background/Aims: Mesenchymal stem cell (MSC based therapies may be useful for treating acute respiratory distress syndrome (ARDS, but the underlying mechanisms are incompletely understood. We investigated the impact of human umbilical cord Wharton's jelly-derived MSC (hUC-MSC secreted factors on alveolar epithelial cells under septic conditions and determined the relevant intracellular signaling pathways. Methods: Human alveolar epithelial cells (AEC and primary human small airway epithelial cells (SAEC were subjected to lipopolysaccharide (LPS with or without the presence of hUC-MSC-conditioned medium (CM. Proliferation and migration of AEC and SAEC were determined via an MTT assay, a wound healing assay and a transwell migration assay (only for AEC. Protein phosphorylation was determined by western blot and the experiments were repeated in presence of small-molecule inhibitors. The hMSC-secretory proteins were identified by LC-MS/MS mass spectrometry. Results: MSC-CM enhanced proliferation and migration. Activation of JNK and P38, but not ERK, was required for the proliferation and migration of AEC and SAEC. Pretreatment of AEC or SAEC with SP600125, an inhibitor of JNK1 or SB200358, an inhibitor of P38, significantly reduced cell proliferation and migration. An array of proteins including TGF-beta receptor type-1, TGF-beta receptor type-2, Ras-related C3 botulinum toxin substrate 1 and Ras-related C3 botulinum toxin substrate 2 which influencing the proliferation and migration of AEC and SAEC were detected in MSC-CM. Conclusion: Our data suggest MSC promote epithelial cell repair through releasing a repertoire of paracrine factors via activation of JNK and P38 MAPK.

  10. Basaloid Squamous Cell Carcinoma Involving the Alveolar Ridge, Buccal & Lingual Vestibule - A Case Report

    Directory of Open Access Journals (Sweden)

    Supriya Koshti

    2013-01-01

    Full Text Available Background: Basaloid squamous cell carcinoma of oral mucosa is a rare and aggressive variant of squamous cell carcinoma. They can be differentiated from squamous cell carcinomas by their distinct clinical and histopathological features. Methods: 45 year old female patient presented with extra oral exophytic mass and intra-oral ulcerative lesion on right buccal mucosa and vestibule. The patient was referred for routine blood examination and radiography followed by incisional biopsy. The biopsy specimen was fixed, processed and stained with Hematoxylin and Eosin for further microscopic examination. Results: On microscopic examination basaloid cells were seen proliferating along with dysplastic squamous cells in the connective tissue stroma. Conclusion: Based on the histopathological findings a diagnosis of ′Basaloid squamous cell carcinoma′ was made. The patient was referred to department of Oral and Maxillofacial Surgery for excision of the lesion followed by radiotherapy.

  11. Enhancement of the repair of dog alveolar cleft by an autologous iliac bone, bone marrow-derived mesenchymal stem cell, and platelet-rich fibrin mixture.

    Science.gov (United States)

    Yuanzheng, Chen; Yan, Gao; Ting, Li; Yanjie, Fu; Peng, Wu; Nan, Bai

    2015-05-01

    Autologous bone graft has been regarded as the criterion standard for the repair of alveolar cleft. However, the most prominent issue in alveolar cleft treatment is the high absorption rate of the bone graft. The authors' objective was to investigate the effects of an autologous iliac bone, bone marrow-derived mesenchymal stem cell, and platelet-rich fibrin mixture on the repair of dog alveolar cleft. Twenty beagle dogs with unilateral alveolar clefts created by surgery were divided randomly into four groups: group A underwent repair with an autologous iliac bone, bone marrow-derived mesenchymal stem cell, and platelet-rich fibrin mixture; group B underwent repair with autologous iliac bone and bone marrow-derived mesenchymal stem cells; group C underwent repair with autologous iliac bone and platelet-rich fibrin; and group D underwent repair with autologous iliac bone as the control. One day and 6 months after transplantation, the transplant volumes and bone mineral density were assessed by quantitative computed tomography. All of the transplants were harvested for hematoxylin and eosin staining 6 months later. Bone marrow-derived mesenchymal stem cells and platelet-rich fibrin transplants formed the greatest amounts of new bone among the four groups. The new bone formed an extensive union with the underlying maxilla in groups A, B, and C. Transplants with the bone marrow-derived mesenchymal stem cells, platelet-rich fibrin, and their mixture retained the majority of their initial volume, whereas the transplants in the control group showed the highest absorption rate. Bone mineral density of transplants with the bone marrow-derived mesenchymal stem cells, platelet-rich fibrin, and their mixture 6 months later was significantly higher than in the control group (p platelet-rich fibrin mixed transplants. Hematoxylin and eosin staining showed that the structure of new bones formed the best in group A. Both bone marrow-derived mesenchymal stem cells and platelet

  12. Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF α mediators

    International Nuclear Information System (INIS)

    Orona, N.S.; Tasat, D.R.

    2012-01-01

    Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 μM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO 3 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO 3 . We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O 2 − ). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O 2 − may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O 2 − may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium‐related diseases. -- Highlights: ► Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ► At low doses uranyl nitrate induces generation of superoxide anion. ► At high doses uranyl nitrate provokes secretion of TNFα. ► Uranyl nitrate induces apoptosis through all the range of doses tested.

  13. Changes in the rat lung after exposure to radon and its progeny: Effects on incorporation of bromodeoxyuridine in epithelial cells and on the incidence of nuclear aberrations in Alveolar macrophages

    International Nuclear Information System (INIS)

    Taya, A.; Morgan, A.; Baker, S.T.; Humphreys, J.A.H.; Collier, C.G.; Bisson, M.

    1994-01-01

    The aim of this study was to investigate some responses of cells in the rat respiratory tract as a function of time after inhalation exposure to various levels of radon and its progeny. Rats were exposed to a constant concentration of radon and its progeny to give cumulative exposure levels of 120, 225, 440 and 990 working level months (WLM). An additional unexposed group of rats served as controls. The end points selected for investigation were (a) the incorporation of bromodeoxyuridine (BrdU) in epithelial cells of the conducting airways and of the alveolar region of the respiratory tract and (b) the incidence of alveolar macrophages with nuclear aberrations. After exposure, the incidence of epithelial cells incorporating BrdU-the labeling index-increased in all regions of the respiratory tract examined, but the increase occurred later in alveolar than in airway epithelial cells. The highest labeling index was found in bronchial epithelial cells, which probably received the highest radiation dose. After an initial induction period, the incidence of alveolar macrophages with nuclear aberrations also increased. The possibility of using the labeling index of alveolar and airway epithelial cells, and/or the incidence of nuclear aberrations in alveolar macrophages, to estimate the radiation dose to various regions of the respiratory tract after exposure of rats to radon and its progeny is discussed. 22 refs., 3 figs., 1 tab

  14. Characterization of T cell receptor assembly and expression in a Ti gamma delta-positive cell line

    DEFF Research Database (Denmark)

    Kuhlmann, J; Caspar-Bauguil, S; Geisler, C

    1993-01-01

    - variants of the T cell Lyon were induced and found to produce all of the Ti/CD3 components, with the exception of Ti-delta. Biochemical analysis indicated that: (1) Ti-gamma/CD3 gamma, delta, epsilon complexes were formed in the endoplasmic reticulum in the absence of Ti-delta; (2) the CD3-zeta chain did...

  15. Blockage of glycolysis by targeting PFKFB3 alleviates sepsis-related acute lung injury via suppressing inflammation and apoptosis of alveolar epithelial cells.

    Science.gov (United States)

    Gong, Yuanqi; Lan, Haibing; Yu, Zhihong; Wang, Meng; Wang, Shu; Chen, Yu; Rao, Haiwei; Li, Jingying; Sheng, Zhiyong; Shao, Jianghua

    2017-09-16

    Sepsis-related acute lung injury (ALI) is characterized by excessive lung inflammation and apoptosis of alveolar epithelial cells resulting in acute hypoxemic respiratory failure. Recent studies indicated that anaerobic glycolysis play an important role in sepsis. However, whether inhibition of aerobic glycolysis exhibits beneficial effect on sepsis-induced ALI is not known. In vivo, a cecal ligation and puncture (CLP)-induced ALI mouse model was set up and mice treated with glycolytic inhibitor 3PO after CLP. The mice treated with the 3PO ameliorated the survival rate, histopathological changes, lung inflammation, lactate increased and lung apoptosis of mice with CLP-induced sepsis. In vitro, the exposure of human alveolar epithelial A549 cells to lipopolysaccharide (LPS) resulted in cell apoptosis, inflammatory cytokine production, enhanced glycolytic flux and reactive oxygen species (ROS) increased. While these changes were attenuated by 3PO treatment. Sequentially, treatment of A549 cells with lactate caused cell apoptosis and enhancement of ROS. Pretreatment with N-acetylcysteine (NAC) significantly lowered LPS and lactate-induced the generation of ROS and cell apoptosis in A549 cells. Therefore, these results indicate that anaerobic glycolysis may be an important contributor in cell apoptosis of sepsis-related ALI. Moreover, LPS specifically induces apoptotic insults to A549 cell through lactate-mediated enhancement of ROS. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Cell adhesion on Ti surface with controlled roughness

    Directory of Open Access Journals (Sweden)

    Burgos-Asperilla, Laura

    2015-06-01

    Full Text Available In this report, the in situ interaction between Saos-2 osteoblast cells and a smooth Ti surface was examined over time. The adhesion kinetics and mechanisms of cellular proliferation were monitored by quartz crystal microbalance (QCM and electrochemical impedance spectroscopy (EIS. The rate of Saos-2 attachment on Ti surfaces, obtained from the measurements performed with the QCM, is a first-order reaction, with k=2.10−3 min−1. The impedance measurements indicate that in the absence of cells, the Ti resistance diminishes over time (7 days, due to the presence of amino acids and proteins from the culture medium that have been a dsorbed, while in the presence of osteoblasts, this decrease is much greater because of the compounds generated by the cells that accelerate the dissolution of Ti.En este trabajo, se ha estudiado la interacción in situ entre células osteoblásticas Saos-2 y una superficie de Ti de rugosidad controlada a lo largo del tiempo. El estudio de la cinética y los mecanismos de proliferación celular de adhesión se ha realizado a través de la microbalanza de cristal de cuarzo (QCM y espectroscopía de impedancia electroquímica (EIS. La velocidad de adhesión de los osteoblastos sobre la superficie de Ti obtenida a través de medidas con la QCM, sigue una reacción de primer orden, con k=2×10−3 min−1. Los ensayos de impedancia indican que, en ausencia de las células, la resistencia del Ti disminuye con el tiempo (7 días, debido a la presencia de aminoácidos y proteínas del medio de cultivo que se han adsorbido, mientras que en presencia de células, esta disminución es mucho mayor debido a los productos metabólicos generados por las células que aceleran la disolución del Ti.

  17. Quantitative Analysis of Proteome Modulations in Alveolar Epithelial Type II Cells in Response to Pulmonary Aspergillus fumigatus Infection.

    Science.gov (United States)

    Seddigh, Pegah; Bracht, Thilo; Molinier-Frenkel, Válerie; Castellano, Flavia; Kniemeyer, Olaf; Schuster, Marc; Weski, Juliane; Hasenberg, Anja; Kraus, Andreas; Poschet, Gernot; Hager, Thomas; Theegarten, Dirk; Opitz, Christiane A; Brakhage, Axel A; Sitek, Barbara; Hasenberg, Mike; Gunzer, Matthias

    2017-12-01

    The ubiquitous mold Aspergillus fumigatus threatens immunosuppressed patients as inducer of lethal invasive aspergillosis. A. fumigatus conidia are airborne and reach the alveoli, where they encounter alveolar epithelial cells (AEC). Previous studies reported the importance of the surfactant-producing AEC II during A. fumigatus infection via in vitro experiments using cell lines. We established a negative isolation protocol yielding untouched primary murine AEC II with a purity >90%, allowing ex vivo analyses of the cells, which encountered the mold in vivo By label-free proteome analysis of AEC II isolated from mice 24h after A. fumigatus or mock infection we quantified 2256 proteins and found 154 proteins to be significantly differentially abundant between both groups (ANOVA p value ≤ 0.01, ratio of means ≥1.5 or ≤0.67, quantified with ≥2 peptides). Most of these proteins were higher abundant in the infected condition and reflected a comprehensive activation of AEC II on interaction with A. fumigatus This was especially represented by proteins related to oxidative phosphorylation, hence energy production. However, the most strongly induced protein was the l-amino acid oxidase (LAAO) Interleukin 4 induced 1 (IL4I1) with a 42.9 fold higher abundance (ANOVA p value 2.91 -10 ). IL4I1 has previously been found in B cells, macrophages, dendritic cells and rare neurons. Increased IL4I1 abundance in AEC II was confirmed by qPCR, Western blot and immunohistology. Furthermore, A. fumigatus infected lungs showed high levels of IL4I1 metabolic products. Importantly, higher IL4I1 abundance was also confirmed in lung tissue from human aspergilloma. Because LAAO are key enzymes for bactericidal product generation, AEC II might actively participate in pathogen defense. We provide insights into proteome changes of primary AEC II thereby opening new avenues to analyze the molecular changes of this central lung cell on infectious threats. Data are available via Proteome

  18. Clinical applications of cell-based approaches in alveolar bone augmentation: a systematic review.

    Science.gov (United States)

    Shanbhag, Siddharth; Shanbhag, Vivek

    2015-01-01

    Cell-based approaches, utilizing adult mesenchymal stem cells (MSCs), are reported to overcome the limitations of conventional bone augmentation procedures. The study aims to systematically review the available evidence on the characteristics and clinical effectiveness of cell-based ridge augmentation, socket preservation, and sinus-floor augmentation, compared to current evidence-based methods in human adult patients. MEDLINE, EMBASE, and CENTRAL databases were searched for related literature. Both observational and experimental studies reporting outcomes of "tissue engineered" or "cell-based" augmentation in ≥5 adult patients alone, or in comparison with non-cell-based (conventional) augmentation methods, were eligible for inclusion. Primary outcome was histomorphometric analysis of new bone formation. Effectiveness of cell-based augmentation was evaluated based on outcomes of controlled studies. Twenty-seven eligible studies were identified. Of these, 15 included a control group (8 randomized controlled trials [RCTs]), and were judged to be at a moderate-to-high risk of bias. Most studies reported the combined use of cultured autologous MSCs with an osteoconductive bone substitute (BS) scaffold. Iliac bone marrow and mandibular periosteum were frequently reported sources of MSCs. In vitro culture of MSCs took between 12 days and 1.5 months. A range of autogenous, allogeneic, xenogeneic, and alloplastic scaffolds was identified. Bovine bone mineral scaffold was frequently reported with favorable outcomes, while polylactic-polyglycolic acid copolymer (PLGA) scaffold resulted in graft failure in three studies. The combination of MSCs and BS resulted in outcomes similar to autogenous bone (AB) and BS. Three RCTs and one controlled trial reported significantly greater bone formation in cell-based than conventionally grafted sites after 3 to 8 months. Based on limited controlled evidence at a moderate-to-high risk of bias, cell-based approaches are comparable, if

  19. Unconventional cells of TiO2 doped with erbium

    International Nuclear Information System (INIS)

    Ribeiro, P.C.; Campos, R.D.; Oliveira, A.S.; Wellen, R.; Diniz, V.C.S.; Costa, A.C.F.M. da

    2016-01-01

    The technology used in TiO_2 solar cells is in constant improvement, new configurations have been developed, aiming practicality and leading to efficiency increase of photovoltaic devices. This paper proposes a new technology for the production of solar cells in order to investigate a better utilization of solar spectrum of TiO2 doped with erbium (Er"3"+), proven by energetic conversion. The Ti_0_,_9Er_0_,_1O2 system was obtained by Pechini method. Nanoparticles have a crystallite size 65.30 nm and surface area 118.48 m"2/g. These characteristics are essential for the formation of the film to be deposited on the conductive glass substrate constituting the cell's photoelectrode. The other side of the cell is the platinum counter electrode. The cell will have the faces sealed by a thermoplastic and, finally the electrolyte will be inserted, then they will be electrically evaluated through energy efficiency and confronted with the literature data base. (author)

  20. Transparent TiO2 nanowire networks via wet corrosion of Ti thin films for dye-sensitized solar cells

    Science.gov (United States)

    Shin, Eunhye; Jin, Saera; Hong, Jongin

    2017-09-01

    Transparent TiO2 nanowire networks were prepared by corrosion of Ti thin films on F-doped SnO2 glass substrates in an alkaline (potassium hydroxide: KOH) solution. The formation of the porous TiO2 nanostructures from the Ti thin films was thoroughly investigated. Dye-sensitized solar cells with a photoanode of 1.2-μm-thick nanowire networks exhibit an average optical transmittance of 40% in the visible light region and a power conversion efficiency of 1.0% under one sun illumination.

  1. Hypoxia inducible factor 3α plays a critical role in alveolarization and distal epithelial cell differentiation during mouse lung development.

    Directory of Open Access Journals (Sweden)

    Yadi Huang

    Full Text Available Lung development occurs under relative hypoxia and the most important oxygen-sensitive response pathway is driven by Hypoxia Inducible Factors (HIF. HIFs are heterodimeric transcription factors of an oxygen-sensitive subunit, HIFα, and a constitutively expressed subunit, HIF1β. HIF1α and HIF2α, encoded by two separate genes, contribute to the activation of hypoxia inducible genes. A third HIFα gene, HIF3α, is subject to alternative promoter usage and splicing, leading to three major isoforms, HIF3α, NEPAS and IPAS. HIF3α gene products add to the complexity of the hypoxia response as they function as dominant negative inhibitors (IPAS or weak transcriptional activators (HIF3α/NEPAS. Previously, we and others have shown the importance of the Hif1α and Hif2α factors in lung development, and here we investigated the role of Hif3α during pulmonary development. Therefore, HIF3α was conditionally expressed in airway epithelial cells during gestation and although HIF3α transgenic mice were born alive and appeared normal, their lungs showed clear abnormalities, including a post-pseudoglandular branching defect and a decreased number of alveoli. The HIF3α expressing lungs displayed reduced numbers of Clara cells, alveolar epithelial type I and type II cells. As a result of HIF3α expression, the level of Hif2α was reduced, but that of Hif1α was not affected. Two regulatory genes, Rarβ, involved in alveologenesis, and Foxp2, a transcriptional repressor of the Clara cell specific Ccsp gene, were significantly upregulated in the HIF3α expressing lungs. In addition, aberrant basal cells were observed distally as determined by the expression of Sox2 and p63. We show that Hif3α binds a conserved HRE site in the Sox2 promoter and weakly transactivated a reporter construct containing the Sox2 promoter region. Moreover, Hif3α affected the expression of genes not typically involved in the hypoxia response, providing evidence for a novel

  2. Mammary alveolar epithelial cells convert to brown adipocytes in post-lactating mice

    DEFF Research Database (Denmark)

    Giordano, Antonio; Perugini, Jessica; Kristensen, David Møbjerg

    2017-01-01

    During pregnancy and lactation, subcutaneous white adipocytes in the mouse mammary gland transdifferentiate reversibly to milk-secreting epithelial cells. In this study, we demonstrate by transmission electron microscopy that in the post-lactating mammary gland interscapular multilocular adipocyt...... organ plasticity...

  3. Characterisation of cellular adhesion reinforcement by multiple bond force spectroscopy in alveolar epithelial cells.

    Science.gov (United States)

    Nguyen, Ngoc-Minh; Angely, Christelle; Andre Dias, Sofia; Planus, Emmanuelle; Filoche, Marcel; Pelle, Gabriel; Louis, Bruno; Isabey, Daniel

    2017-07-01

    Integrin-mediated adhesion is a key process by which cells physically connect with their environment, and express sensitivity and adaptation through mechanotransduction. A critical step of cell adhesion is the formation of the first bonds which individually generate weak contacts (∼tens pN) but can sustain thousand times higher forces (∼tens nN) when associated. We propose an experimental validation by multiple bond force spectroscopy (MFS) of a stochastic model predicting adhesion reinforcement permitted by non-cooperative, multiple bonds on which force is homogeneously distributed (called parallel bond configuration). To do so, spherical probes (diameter: 6.6 μm), specifically coated by RGD-peptide to bind integrins, are used to statically indent and homogenously stretch the multiple bonds created for short contact times (2 s) between the bead and the surface of epithelial cells (A549). Using different separation speeds (v = 2, 5, 10 μm/s) and measuring cellular Young's modulus as well as the local stiffness preceding local rupture events, we obtain cell-by-cell the effective loading rates both at the global cell level and at the local level of individual constitutive bonds. Local rupture forces are in the range: f*=60-115 pN , whereas global rupture (detachment) forces reach F*=0.8-1.7 nN . Global and local rupture forces both exhibit linear dependencies with the effective loading rate, the slopes of these two linear relationships providing an estimate of the number of independent integrin bonds constituting the tested multiple bond structure (∼12). The MFS method enables to validate the reinforcement of integrin-mediated adhesion induced by the multiple bond configuration in which force is homogeneously distributed amongst parallel bonds. Local rupture events observed in the course of a spectroscopy manoeuver (MFS) lead to rupture force values considered in the literature as single-integrin bonds. Adhesion reinforcement permitted by the parallel

  4. Edaravone protects rats and human pulmonary alveolar epithelial cells against hyperoxia injury: heme oxygenase-1 and PI3K/Akt pathway may be involved.

    Science.gov (United States)

    Cao, Huifang; Feng, Ying; Ning, Yunye; Zhang, Zinan; Li, Weihao; Li, Qiang

    2015-01-01

    Hyperoxic acute lung injury (HALI) is a clinical syndrome as a result of prolonged supplement of high concentrations of oxygen. As yet, no specific treatment is available for HALI. The present study aims to investigate the effects of edaravone on hyperoxia-induced oxidative injury and the underlying mechanism. We treated rats and human pulmonary alveolar epithelial cells with hyperoxia and different concentration of edaravone, then examined the effects of edaravone on cell viability, cell injury and two oxidative products. The roles of heme oxygenase-1 (HO-1) and PI3K/Akt pathway were explored using Western blot and corresponding inhibitors. The results showed that edaravone reduced lung biochemical alterations induced by hyperoxia and mortality of rats, dose-dependently alleviated cell mortality, cell injury, and peroxidation of cellular lipid and DNA oxidative damage. It upregulated cellular HO-1 expression and activity, which was reversed by PI3K/Akt pathway inhibition. The administration of zinc protoporphyrin-IX, a HO-1 inhibitor, and LY249002, a PI3K/Akt pathway inhibitor, abolished the protective effects of edaravone in cells. This study indicates that edaravone protects rats and human pulmonary alveolar epithelial cells against hyperoxia-induced injury and the antioxidant effect may be related to upregulation of HO-1, which is regulated by PI3K/Akt pathway.

  5. Osteoblast Cell Response on the Ti6Al4V Alloy Heat-Treated

    Directory of Open Access Journals (Sweden)

    Mercedes Paulina Chávez-Díaz

    2017-04-01

    Full Text Available In an effort to examine the effect of the microstructural changes of the Ti6Al4V alloy, two heat treatments were carried out below (Ti6Al4V800 and above (Ti6Al4V1050 its β-phase transformation temperature. After each treatment, globular and lamellar microstructures were obtained. Saos-2 pre-osteoblast human osteosarcoma cells were seeded onto Ti6Al4V alloy disks and immersed in cell culture for 7 days. Electrochemical assays in situ were performed using OCP and EIS measurements. Impedance data show a passive behavior for the three Ti6Al4V alloys; additionally, enhanced impedance values were recorded for Ti6Al4V800 and Ti6Al4V1050 alloys. This passive behavior in culture medium is mostly due to the formation of TiO2 during their sterilization. Biocompatibility and cell adhesion were characterized using the SEM technique; Ti6Al4V as received and Ti6Al4V800 alloys exhibited polygonal and elongated morphology, whereas Ti6Al4V1050 alloy displayed a spherical morphology. Ti and O elements were identified by EDX analysis due to the TiO2 and signals of C, N and O, related to the formation of organic compounds from extracellular matrix. These results suggest that cell adhesion is more likely to occur on TiO2 formed in discrete α-phase regions (hcp depending on its microstructure (grains.

  6. Ablation of the Leptin receptor in Myeloid Cells Impairs Pulmonary Clearance of Streptococcus Pneumoniae and Alveolar Macrophage Bactericidal Function.

    Science.gov (United States)

    Mancuso, Peter; Curtis, Jeffrey L; Freeman, Christine M; Peters-Golden, Marc; Weinberg, Jason B; Myers, Martin G

    2018-03-22

    Leptin is a pleiotropic hormone produced by white adipose tissue that regulates appetite and many physiologic functions including the immune response to infection. Genetic leptin deficiency in humans and mice impairs host defenses against respiratory tract infections. Since leptin deficiency is associated with obesity and other metabolic abnormalities, we generated mice that lack the leptin receptor (LepRb) in cells of the myeloid linage (LysM-LepRb-KO) to evaluate its impact in lean metabolically normal mice in a murine model of pneumococcal pneumonia. We observed higher lung and spleen bacterial burdens in LysM-LepRb-KO mice following an intratracheal challenge with S. pneumoniae. Although numbers of leukocytes recovered from bronchoalveolar lavage fluid did not differ between groups, we did observe higher levels of pulmonary IL-13 and TNFα in LysM-LepRb-KO mice 48 h post-infection. Phagocytosis and killing of ingested S. pneumoniae were also impaired in alveolar macrophages (AM)s from LysM-LepRb-KO mice in vitro, and was associated with reduced LTB4 and enhanced PGE2 synthesis in vitro. Pretreatment of AMs with LTB4 and the cyclooxygenase inhibitor, indomethacin, restored phagocytosis but not bacterial killing in vitro. These results, confirm our previous observations in leptin-deficient (ob/ob) and fasted mice, and demonstrate that decreased leptin action, as opposed to metabolic irregularities associated with obesity or starvation, are responsible for the defective host defense against pneumococcal pneumonia. They also provide novel targets for therapeutic intervention in humans with bacterial pneumonia.

  7. Sonicated Protein Fractions of Mycoplasma hyopneumoniae Induce Inflammatory Responses and Differential Gene Expression in a Murine Alveolar Macrophage Cell Line.

    Science.gov (United States)

    Damte, Dereje; Lee, Seung-Jin; Birhanu, Biruk Tesfaye; Suh, Joo-Won; Park, Seung-Chun

    2015-12-28

    Mycoplasma hyopneumoniae is known to cause porcine enzootic pneumonia (EP), an important disease in swine production. The objective of this study was to examine the effects of sonicated protein fractions of M. hyopneumoniae on inflammatory response and gene expression in the murine alveolar macrophage MH-S cell line. The effects of sonicated protein fractions and intact M. hyopneumoniae on the gene expression of cytokines and iNOS were assessed using RT-PCR. The Annealing Control Primer (ACP)-based PCR method was used to screen differentially expressed genes. Increased transcription of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, COX-2, and iNOS mRNA was observed after exposure to the supernatant (SPT), precipitant (PPT), and intact M. hyopneumoniae protein. A time-dependent analysis of the mRNA expression revealed an upregulation after 4 h for IL-6 and iNOS and after 12 h for IL-1β and TNF-α, for both SPT and PPT; the fold change in COX-2 expression was less. A dose- and time-dependent correlation was observed in nitrite (NO) production for both protein fractions; however, there was no significant difference between the effects of the two protein fractions. In a differential gene analysis, PCR revealed differential expression for nine gene bands after 3 h of stimulation - only one gene was downregulated, while the remaining eight were upregulated. The results of this study provide insights that help improve our understanding of the mechanisms underlying the pathogenesis of and macrophage defenses against M. hyopneumoniae assault, and suggest targets for future studies on therapeutic interventions for M. hyopneumoniae infections.

  8. TiO2-Anatase Nanowire Dispersed Composite Electrode for Dye-Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Asagoe, K; Suzuki, Y; Ngamsinlapasathian, S; Yoshikawa, S

    2007-01-01

    TiO 2 anatase nanowires have been prepared by a hydrothermal process followed by post-heat treatment in air. TiO 2 nanoparticle/TiO 2 nanowire composite electrodes were prepared for dye-sensitized solar cells (DSC) in order to improve light-to-electricity conversion efficiency. The TiO 2 NP/TiO 2 NW composite cells showed higher DSC performance than ordinary nanoparticle cells and fully nanowire cells: efficiency (η = 6.53 % for DSC with 10% nanowire, whereas 5.59% for 0% nanowire, and 2.42% for 100% nanowire

  9. Design-based stereological analysis of the lung parenchymal architecture and alveolar type II cells in surfactant protein A and D double deficient mice

    DEFF Research Database (Denmark)

    Jung, A; Allen, L; Nyengaard, Jens Randel

    2005-01-01

    Alveolar epithelial type II cells synthesize and secrete surfactant. The surfactant-associated proteins A and D (SP-A and SP-D), members of the collectin protein family, participate in pulmonary immune defense, modulation of inflammation, and surfactant metabolism. Both proteins are known to have......, but the mean volume of a single lamellar body remains constant. These results demonstrate that chronic deficiency of SP-A and SP-D in mice leads to parenchymal remodeling, type II cell hyperplasia and hypertrophy, and disturbed intracellular surfactant metabolism. The design-based stereological approach...

  10. The cytoprotective role of DJ-1 and p45 NFE2 against human primary alveolar type II cell injury and emphysema.

    Science.gov (United States)

    Tan, Li Hui; Bahmed, Karim; Lin, Chih-Ru; Marchetti, Nathaniel; Bolla, Sudhir; Criner, Gerard J; Kelsen, Steven; Madesh, Muniswamy; Kosmider, Beata

    2018-02-23

    Emphysema is characterized by irreversibly enlarged airspaces and destruction of alveolar walls. One of the factors contributing to this disease pathogenesis is an elevation in extracellular matrix (ECM) degradation in the lung. Alveolar type II (ATII) cells produce and secrete pulmonary surfactants and proliferate to restore the epithelium after damage. We isolated ATII cells from control non-smokers, smokers and patients with emphysema to determine the role of NFE2 (nuclear factor, erythroid-derived 2). NFE2 is a heterodimer composed of two subunits, a 45 kDa (p45 NFE2) and 18 kDa (p18 NFE2) polypeptides. Low expression of p45 NFE2 in patients with emphysema correlated with a high ECM degradation. Moreover, we found that NFE2 knockdown increased cell death induced by cigarette smoke extract. We also studied the cross talk between p45 NFE2 and DJ-1. DJ-1 protein is a redox-sensitive chaperone that protects cells from oxidative stress. We detected that cigarette smoke significantly increased p45 NFE2 levels in DJ-1 KO mice compared to wild-type mice. Our results indicate that p45 NFE2 expression is induced by exposure to cigarette smoke, has a cytoprotective activity against cell injury, and its downregulation in human primary ATII cells may contribute to emphysema pathogenesis.

  11. Gene expression profiles of human dendritic cells interacting with Aspergillus fumigatus in a bilayer model of the alveolar epithelium/endothelium interface.

    Directory of Open Access Journals (Sweden)

    Charles Oliver Morton

    Full Text Available The initial stages of the interaction between the host and Aspergillus fumigatus at the alveolar surface of the human lung are critical in the establishment of aspergillosis. Using an in vitro bilayer model of the alveolus, including both the epithelium (human lung adenocarcinoma epithelial cell line, A549 and endothelium (human pulmonary artery epithelial cells, HPAEC on transwell membranes, it was possible to closely replicate the in vivo conditions. Two distinct sub-groups of dendritic cells (DC, monocyte-derived DC (moDC and myeloid DC (mDC, were included in the model to examine immune responses to fungal infection at the alveolar surface. RNA in high quantity and quality was extracted from the cell layers on the transwell membrane to allow gene expression analysis using tailored custom-made microarrays, containing probes for 117 immune-relevant genes. This microarray data indicated minimal induction of immune gene expression in A549 alveolar epithelial cells in response to germ tubes of A. fumigatus. In contrast, the addition of DC to the system greatly increased the number of differentially expressed immune genes. moDC exhibited increased expression of genes including CLEC7A, CD209 and CCL18 in the absence of A. fumigatus compared to mDC. In the presence of A. fumigatus, both DC subgroups exhibited up-regulation of genes identified in previous studies as being associated with the exposure of DC to A. fumigatus and exhibiting chemotactic properties for neutrophils, including CXCL2, CXCL5, CCL20, and IL1B. This model closely approximated the human alveolus allowing for an analysis of the host pathogen interface that complements existing animal models of IA.

  12. Alveolar Soft Part Sarcoma.

    Science.gov (United States)

    Jaber, Omar I; Kirby, Patricia A

    2015-11-01

    Alveolar soft part sarcoma is a rare neoplasm usually arising in the soft tissues of the lower limbs in adults and in the head and neck region in children. It presents primarily as a slowly growing mass or as metastatic disease. It is characterized by a specific chromosomal alteration, der(17)t(X:17)(p11:q25), resulting in fusion of the transcription factor E3 (TFE3) with alveolar soft part sarcoma critical region 1 (ASPSCR1) at 17q25. This translocation is diagnostically useful because the tumor nuclei are positive for TFE3 by immunohistochemistry. Real-time polymerase chain reaction to detect the ASPSCR1-TFE3 fusion transcript on paraffin-embedded tissue blocks has been shown to be more sensitive and specific than detection of TFE3 by immunohistochemical stain. Cathepsin K is a relatively recent immunohistochemical stain that can aid in the diagnosis. The recent discovery of the role of the ASPSCR1-TFE3 fusion protein in the MET proto-oncogene signaling pathway promoting angiogenesis and cell proliferation offers a promising targeted molecular therapy.

  13. Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF α mediators

    Energy Technology Data Exchange (ETDEWEB)

    Orona, N.S. [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); Tasat, D.R., E-mail: deborah.tasat@unsam.edu.ar [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); School of Dentistry, University of Buenos Aires, M. T. de Alvear 2142 (1122), Buenos Aires (Argentina)

    2012-06-15

    Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 μM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO{sub 3} 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO{sub 3}. We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O{sub 2}{sup −}). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O{sub 2}{sup −} may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O{sub 2}{sup −} may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium‐related diseases. -- Highlights: ► Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ► At low doses uranyl nitrate induces generation of superoxide anion. ► At high doses uranyl nitrate provokes secretion of TNFα. ► Uranyl nitrate induces apoptosis through

  14. DJ-1 Modulates Nuclear Erythroid 2–Related Factor-2–Mediated Protection in Human Primary Alveolar Type II Cells in Smokers

    Science.gov (United States)

    Bahmed, Karim; Messier, Elise M.; Zhou, Wenbo; Tuder, Rubin M.; Freed, Curt R.; Chu, Hong Wei; Kelsen, Steven G.; Bowler, Russell P.; Mason, Robert J.

    2016-01-01

    Cigarette smoke (CS) is a main source of oxidative stress and a key risk factor for emphysema, which consists of alveolar wall destruction. Alveolar type (AT) II cells are in the gas exchange regions of the lung. We isolated primary ATII cells from deidentified organ donors whose lungs were not suitable for transplantation. We analyzed the cell injury obtained from nonsmokers, moderate smokers, and heavy smokers. DJ-1 protects cells from oxidative stress and induces nuclear erythroid 2–related factor-2 (Nrf2) expression, which activates the antioxidant defense system. In ATII cells isolated from moderate smokers, we found DJ-1 expression by RT-PCR, and Nrf2 and heme oxygenase (HO)-1 translocation by Western blotting and immunocytofluorescence. In ATII cells isolated from heavy smokers, we detected Nrf2 and HO-1 cytoplasmic localization. Moreover, we found high oxidative stress, as detected by 4-hydroxynonenal (4-HNE) (immunoblotting), inflammation by IL-8 and IL-6 levels by ELISA, and apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay in ATII cells obtained from heavy smokers. Furthermore, we detected early DJ-1 and late Nrf2 expression after ATII cell treatment with CS extract. We also overexpressed DJ-1 by adenovirus construct and found that this restored Nrf2 and HO-1 expression and induced nuclear translocation in heavy smokers. Moreover, DJ-1 overexpression also decreased ATII cell apoptosis caused by CS extract in vitro. Our results indicate that DJ-1 activates the Nrf2-mediated antioxidant defense system. Furthermore, DJ-1 overexpression can restore the impaired Nrf2 pathway, leading to ATII cell protection in heavy smokers. This suggests a potential therapeutic strategy for targeting DJ-1 in CS-related lung diseases. PMID:27093578

  15. /TiN Resistive RAM (RRAM) Cells

    Science.gov (United States)

    Chen, Z. X.; Fang, Z.; Wang, Y.; Yang, Y.; Kamath, A.; Wang, X. P.; Singh, N.; Lo, G.-Q.; Kwong, D.-L.; Wu, Y. H.

    2014-11-01

    We present a study of Ni silicide as the bottom electrode in HfO2-based resistive random-access memory cells. Various silicidation conditions were used for each device, yielding different Ni concentrations within the electrode. A higher concentration of Ni in the bottom electrode was found to cause a parasitic SET operation during certain RESET operation cycles, being attributed to field-assisted Ni cation migration creating a Ni filament. As such, the RESET is affected unless an appropriate RESET voltage is used. Bottom electrodes with lower concentrations of Ni were able to switch at ultralow currents (RESET current <1 nA) by using a low compliance current (<500 nA). The low current is attributed to the tunneling barrier formed by the native SiO2 at the Ni silicide/HfO2 interface.

  16. Comparison of Omadacycline and Tigecycline Pharmacokinetics in the Plasma, Epithelial Lining Fluid, and Alveolar Cells of Healthy Adult Subjects.

    Science.gov (United States)

    Gotfried, Mark H; Horn, Karolyn; Garrity-Ryan, Lynne; Villano, Stephen; Tzanis, Evan; Chitra, Surya; Manley, Amy; Tanaka, S Ken; Rodvold, Keith A

    2017-09-01

    The steady-state concentrations of omadacycline and tigecycline in the plasma, epithelial lining fluid (ELF), and alveolar cells (AC) of 58 healthy adult subjects were obtained. Subjects were administered either omadacycline at 100 mg intravenously (i.v.) every 12 h for two doses followed by 100 mg i.v. every 24 h for three doses or tigecycline at an initial dose of 100 mg i.v. followed by 50 mg i.v. every 12 h for six doses. A bronchoscopy and bronchoalveolar lavage were performed once in each subject following the start of the fifth dose of omadacycline at 0.5, 1, 2, 4, 8, 12, or 24 h and after the start of the seventh dose of tigecycline at 2, 4, 6, or 12 h. The value of the area under the concentration-time curve (AUC) from time zero to 24 h postdosing (AUC 0-24 ) (based on mean concentrations) in ELF and the ratio of the ELF to total plasma omadacycline concentration based on AUC 0-24 values were 17.23 mg · h/liter and 1.47, respectively. The AUC 0-24 value in AC was 302.46 mg · h/liter, and the ratio of the AC to total plasma omadacycline concentration was 25.8. In comparison, the values of the AUC from time zero to 12 h postdosing (AUC 0-12 ) based on the mean concentrations of tigecycline in ELF and AC were 3.16 and 38.50 mg · h/liter, respectively. The ratio of the ELF and AC to total plasma concentrations of tigecycline based on AUC 0-12 values were 1.71 and 20.8, respectively. The pharmacokinetic advantages of higher and sustained concentrations of omadacycline compared to those of tigecycline in plasma, ELF, and AC suggest that omadacycline is a promising antibacterial agent for the treatment of lower respiratory tract bacterial infections caused by susceptible pathogens. Copyright © 2017 Gotfried et al.

  17. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes junction for dye sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Nguyen Huy Hao

    2016-08-01

    Full Text Available The dye sensitized solar cell (DSSC, which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

  18. Preparation of Nanoporous TiO2 Electrodes for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Hsiue-Hsyan Wang

    2011-01-01

    Full Text Available Nano-porous TiO2 thin films have been widely used as the working electrodes in dye-sensitized solar cells (DSSCs. In this work, the phase-pure anatase TiO2 (a-TiO2 and rutile TiO2 (r-TiO2 have been prepared using hydrothermal processes. The investigation of photo-to-electron conversion efficiency of DSSCs fabricated from mixed-TiO2 with a-TiO2 and r-TiO2 ratio of 80 : 20 (A8R2 was performed and compared to that from commercial TiO2 (DP-25. The results showed higher efficiency of DSSC for A8R2 cells with same dependence of cell efficiency on the film thickness for both A8R2 and DP-25 cells. The best efficiency obtained in this work is 5.2% from A8R2 cell with TiO2 film thickness of 12.0 μm. The correlation between the TiO2 films thickness and photoelectron chemical properties of DSSCs fabricated from A8R2 and DP-25 was compared and discussed.

  19. Differentiation and cytokine synthesis of human alveolar osteoblasts compared to osteoblast-like cells (MG63) in response to titanium surfaces.

    Science.gov (United States)

    Rausch-fan, Xiaohui; Qu, Zhe; Wieland, Marco; Matejka, Michael; Schedle, Andreas

    2008-01-01

    The aim of this study was to investigate the influence of different implant surface topographies and chemistries on the expression of differentiation/proliferation markers on MG63 cells and primary human alveolar osteoblasts. Hydrophobic acid-etched (A) and hydrophobic coarse-grit-blasted, acid-etched (SLA) surfaces and hydrophilic acid-etched (modA) and hydrophilic coarse-grit-blasted (modSLA) surfaces were produced. Thereby, modA and modSLA surfaces were rinsed under nitrogen protection and stored in a sealed glass tube containing isotonic NaCl solution at pH 4-6. Tissue culture plates without specimens served as controls. The behavior of MG63 cells and primary human alveolar osteoblasts (AOB) grown on all surfaces was compared through determination of alkaline phosphatase (ALP) activity, cell proliferation ((3)H-thymidin incorporation, MTT colorimetric assay) and expression of osteocalcin (OC), osteoprotegerin (OPG), transforming growth factor-beta1 (TGF-beta(1)) and vascular endothelial growth factor (VEGF), detected with commercial available test kits. Proliferation of MG63 and primary cells was highest on controls, followed by A surfaces, modA and SLA surfaces being almost on the same level and lowest on modSLA surfaces. modSLA surfaces exhibited highest ALP and OC production, followed by SLA, modA and A surfaces. Proliferation and OC production were comparable for MG63 cells and AOB. OPG, TGF-beta(1) and VEGF produced on primary cells showed a slightly different rank order on different surfaces compared to MG63 cells. modSLA still showed the highest production of OPG, TGF-beta(1) and VEGF, but was followed by modA, SLA and A. Statistical significance was checked by ANOVA (pmodA surfaces showed enhanced expression of OPG, TGF-beta(1) and VEGF on MG63 cells compared to primary human alveolar osteoblasts. Overall, the lowest proliferation rates and the highest expressions of differentiation markers and growth factor productions were observed on modSLA.

  20. Proteinosis alveolar pulmonar Pulmonary alveolar proteinosis

    Directory of Open Access Journals (Sweden)

    Concepción Sánchez Infante

    2011-12-01

    Full Text Available La proteinosis alveolar pulmonar es una enfermedad respiratoria crónica, caracterizada por alteración en el metabolismo del surfactante, lo que determina su acumulación anormal en el espacio alveolar. Es una enfermedad extremadamente rara. Se han reportado solamente 500 casos en la literatura. Se describió por primera vez en 1958. Se presenta un caso de proteinosis alveolar pulmonar en un lactante de 2 meses, con desnutrición proteico energética, que ingresa por dificultad respiratoria e hipoxemia, y, con imágenes radiológicas de tipo retículo-nodulillar, en vidrio deslustrado, en el cual se plantea inicialmente el diagnóstico de bronconeumonía. Ante la evolución desfavorable y no respuesta al tratamiento, se realizó un estudio para descartar enfermedades pulmonares crónicas. El paciente fallece y se confirma el diagnóstico por anatomía patológica. Se realiza una revisión del tema.The pulmonary alveolar proteinosis is a chronic respiratory disease characterized by surfactant metabolism alteration determining its abnormal accumulation in the alveolar space. It is a disease very rare and in literature only 500 cases have been reported; it was described for the first time in 1958. This is a case presentation of pulmonary alveolar proteinosis in an infant aged 2 months with energetic protein malnutrition admitted due to respiratory difficulty and hypoxemia and with radiologic images of the reticulonodulillary, in frosting glass, where initially is made the diagnosis of bronchopneumonia. In the face of unfavorable evolution and no response to treatment, a study was conducted to rule out chronic pulmonary diseases. Patient died confirming the diagnosis according to the pathologic anatomy. A review on subject is carried out.

  1. TiN-conductive carbon black composite as counter electrode for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Li, G.R.; Wang, F.; Song, J.; Xiong, F.Y.; Gao, X.P.

    2012-01-01

    Highlights: ► The TiN nanoparticles are highly dispersed on conductive carbon black matrix (CCB). ► The well dispersion of TiN nanoparticles can improve electrochemical performance. ► The TiN/CCB shows a high photovoltaic performance with high conversion efficiency. - Abstract: TiN-conductive carbon black (CCB)/Ti electrodes are prepared by the nitridation of TiO 2 –CCB mixtures filmed on metallic Ti substrate in ammonia atmosphere. It is demonstrated from X-ray diffraction (XRD) and scanning electron microscopy (SEM) that TiN nanoparticles are highly dispersed on the CCB matrix in the composites. TiN–CCB/Ti electrodes show outstanding electrochemical performances as compared to individual TiN/Ti and CCB/Ti electrodes. In particular, the dye-sensitized solar cell (DSSC) using TiN–CCB (1:1, mass ratio)/Ti electrode presents an energy conversion efficiency of 7.92%, which is higher than that (6.59%) of the device using Pt/FTO (fluorine doped tin oxide) electrode measured under the same test conditions. Based on the analysis of cyclic voltammetry (CV) and electrochemical impedance spectra (EIS), the enhancements for the electrochemical and photochemical performance of TiN–CCB/Ti electrodes are attributed to the fact that the dispersed TiN nanoparticles in the CCB matrix provide an improved electrocatalytic activity and a facilitated diffusion for triiodine ions. This work shows a facile approach to develop metal nitrides–carbon composites as counter electrodes for DSSCs. High energy conversion efficiency and low lost will make the composites have significant potential for replacing the conventional Pt/FTO electrodes in DSSCs.

  2. Importance of the functional state of alveolar macrophages of the lungs for hygienic evaluation of protective reactions and cell damage due to atmospheric pollution

    Energy Technology Data Exchange (ETDEWEB)

    Tusl, M; Vyskocil, A; Duerrer, I; Aulika, B V; Litvinov, N N; Merkur' eva, R V

    1983-01-01

    Total number of cells, their viability and ability to adhesion were examined in surface alveolar macrophages isolated from rat livers after exposure to sulphur dioxide during 2, 4 and 6 weeks (0.05, 0.5, 1.0 and 5.0 mg/m3); to nitrogen oxide during 5, 8 and 15 hours, 28 and 56 days (19 mg/m3) and to carbon monoxide during 2, 28 and 56 days (0.01% or 10 MAC). In the experiment with exposure to sulphur dioxide, the activity of enzymes of varying localization in the macrophages - soluble in the cytoplasm (lactate dehydrogenase) and connected with subcellular structures - lysosomes (beta-galactosidase, beta-glucosidase and acid phosphatase) was tested by means of biochemical methods in parallel with cytological examinations. Low concentrations of various chemical contaminants of the atmospheric air (sulphur dioxide, nitrogen oxides, carbon monoxide) have an unfavourable biological effect on rats, manifest in the impairment of local immunity, i.e., decreased number of alveolar macrophages, disturbance of their viability and reduced ability of the macrophages to adhesion. At the same time, sulphur dioxide induces enzyme disorganization in lactate dehydrogenase and in a number of lysosomal enzymes of the macrophages. These results serve as a basis for the recommendation of cytobiochemical methods of elaborating methodological approaches to the regulation of environmental factors. Alveolar macrophages as a constituent part of the mononuclear phagocytic system ensuring local non-specific and specific resistance of the organism form one of the most important cellular mechanisms of protection of the organism against the harmful effect of environmental factors including chemical contaminants of the atmospheric air (1, 2).

  3. Toxicological consequences of TiO2, SiC nanoparticles and multi-walled carbon nanotubes exposure in several mammalian cell types: an in vitro study

    International Nuclear Information System (INIS)

    Barillet, Sabrina; Simon-Deckers, Angelique; Herlin-Boime, Nathalie; Mayne-L'Hermite, Martine; Reynaud, Cecile; Cassio, Doris; Gouget, Barbara; Carriere, Marie

    2010-01-01

    The development of nanotechnologies may lead to dissemination of potentially toxic nanoparticles in the environment. Toxicology of these nano-sized particles is thus attracting attention of public and governments worldwide. Our research is focused on the in vitro response of eukaryotic cells to nanoparticles exposure. For this purpose, we used cellular models of primary target organs (lung: A549 alveolar epithelial cells), or secondary target organs (liver: WIF-B9, Can-10 and kidneys: NRK-52E, LLC-PK1 proximal cells), i.e., organs exposed if nanoparticles are translocated through epithelial barriers. These cells were exposed to TiO 2 , SiC nanoparticles or multi-walled carbon nanotubes (MWCNT). The influence of nanoparticles physico-chemical characteristics on various toxicological endpoints (cytotoxicity, reactive oxygen species generation, genotoxicity) was specified. Our data demonstrate that nanoparticles toxicity depend on their size, morphology, and chemical composition, the finest, spherical shaped, and anatase TiO 2 nanoparticles being the more cytotoxic to NRK-52E cells, while SiC nanoparticles exert almost no cytotoxicity. MWCNT cytotoxicity neither depended on their length, nor on the presence of metal impurities. Nanoparticles cytotoxicity also depended on the exposed cell line. All the tested nanoparticles were uptaken by cells and caused intracellular reactive oxygen species generation. Relative to genotoxic effects, DNA strand breaks were detected in NRK-52E cells via the alkaline comet assay after exposure of cells to TiO 2 nanoparticles and to a lesser extent after exposure to MWCNT, but no double strand breaks were detected. The originality of this study lies on the panel of nanomaterials which were tested on a variety of cell lines. All these data may lead to a better understanding of nanomaterial toxicity and hazards for health.

  4. Stem cell property of postmigratory cranial neural crest cells and their utility in alveolar bone regeneration and tooth development.

    Science.gov (United States)

    Chung, Il-Hyuk; Yamaza, Takayoshi; Zhao, Hu; Choung, Pill-Hoon; Shi, Songtao; Chai, Yang

    2009-04-01

    The vertebrate neural crest is a multipotent cell population that gives rise to a variety of different cell types. We have discovered that postmigratory cranial neural crest cells (CNCCs) maintain mesenchymal stem cell characteristics and show potential utility for the regeneration of craniofacial structures. We are able to induce the osteogenic differentiation of postmigratory CNCCs, and this differentiation is regulated by bone morphogenetic protein (BMP) and transforming growth factor-beta signaling pathways. After transplantation into a host animal, postmigratory CNCCs form bone matrix. CNCC-formed bones are distinct from bones regenerated by bone marrow mesenchymal stem cells. In addition, CNCCs support tooth germ survival via BMP signaling in our CNCC-tooth germ cotransplantation system. Thus, we conclude that postmigratory CNCCs preserve stem cell features, contribute to craniofacial bone formation, and play a fundamental role in supporting tooth organ development. These findings reveal a novel function for postmigratory CNCCs in organ development, and demonstrate the utility of these CNCCs in regenerating craniofacial structures.

  5. Low temperature fabrication of perovskite solar cells with TiO2 nanoparticle layers

    International Nuclear Information System (INIS)

    Kanayama, Masato; Oku, Takeo; Suzuki, Atsushi; Yamada, Masahiro; Sakamoto, Hiroki; Minami, Satoshi; Kohno, Kazufumi

    2016-01-01

    TiO 2 /CH 3 NH 3 PbI 3 -based photovoltaic devices were fabricated by a spin-coating method using a mixture solution. TiO 2 require high-temperature processing to achieve suitably high carrier mobility. TiO 2 electron transport layers and TiO 2 scaffold layers for the perovskite were fabricated from TiO 2 nanoparticles with different grain sizes. The photovoltaic properties and microstructures of solar cells were characterized. Nanoparticle sizes of these TiO 2 were 23 nm and 3 nm and the performance of solar cells was improved by combination of two TiO 2 nanoparticles

  6. Perovskite solar cell with an efficient TiO₂ compact film.

    Science.gov (United States)

    Ke, Weijun; Fang, Guojia; Wang, Jing; Qin, Pingli; Tao, Hong; Lei, Hongwei; Liu, Qin; Dai, Xin; Zhao, Xingzhong

    2014-09-24

    A perovskite solar cell with a thin TiO2 compact film prepared by thermal oxidation of sputtered Ti film achieved a high efficiency of 15.07%. The thin TiO2 film prepared by thermal oxidation is very dense and inhibits the recombination process at the interface. The optimum thickness of the TiO2 compact film prepared by thermal oxidation is thinner than that prepared by spin-coating method. Also, the TiO2 compact film and the TiO2 porous film can be sintered at the same time. This one-step sintering process leads to a lower dark current density, a lower series resistance, and a higher recombination resistance than those of two-step sintering. Therefore, the perovskite solar cell with the TiO2 compact film prepared by thermal oxidation has a higher short-circuit current density and a higher fill factor.

  7. Low temperature fabrication of perovskite solar cells with TiO{sub 2} nanoparticle layers

    Energy Technology Data Exchange (ETDEWEB)

    Kanayama, Masato; Oku, Takeo, E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi [Department of Materials Science, The University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga 522-8533 (Japan); Yamada, Masahiro; Sakamoto, Hiroki [Energy Technology Laboratories, Osaka Gas Co., Ltd., Osaka 554-0051 (Japan); Minami, Satoshi; Kohno, Kazufumi [Frontier Materials Laboratories, Osaka Gas Chemicals Co., Ltd., Osaka 554-0051 (Japan)

    2016-02-01

    TiO{sub 2}/CH{sub 3}NH{sub 3}PbI{sub 3}-based photovoltaic devices were fabricated by a spin-coating method using a mixture solution. TiO{sub 2} require high-temperature processing to achieve suitably high carrier mobility. TiO{sub 2} electron transport layers and TiO{sub 2} scaffold layers for the perovskite were fabricated from TiO{sub 2} nanoparticles with different grain sizes. The photovoltaic properties and microstructures of solar cells were characterized. Nanoparticle sizes of these TiO{sub 2} were 23 nm and 3 nm and the performance of solar cells was improved by combination of two TiO{sub 2} nanoparticles.

  8. Effect of Emdogain enamel matrix derivative and BMP-2 on the gene expression and mineralized nodule formation of alveolar bone proper-derived stem/progenitor cells.

    Science.gov (United States)

    Fawzy El-Sayed, Karim M; Dörfer, Christof; Ungefroren, Hendrick; Kassem, Neemat; Wiltfang, Jörg; Paris, Sebastian

    2014-07-01

    The objective of this study was to evaluate the effect of Emdogain (Enamel Matrix Derivative, EMD) and Bone Morphogenetic Protein-2 (BMP-2), either solely or in combination, on the gene expression and mineralized nodule formation of alveolar bone proper-derived stem/progenitor cells. Stem/progenitor cells were isolated from human alveolar bone proper, magnetically sorted using STRO-1 antibodies, characterized flowcytometrically for their surface markers' expression, and examined for colony formation and multilineage differentiation potential. Subsequently, cells were treated over three weeks with 100 μg/ml Emdogain (EMD-Group), or 100 ng/ml BMP-2 (BMP-Group), or a combination of 100 ng/ml BMP-2 and 100 μg/ml Emdogain (BMP/EMD-Group). Unstimulated stem/progenitor cells (MACS(+)-Group) and osteoblasts (OB-Group) served as controls. Osteogenic gene expression was analyzed using RTq-PCR after 1, 2 and 3 weeks (N = 3/group). Mineralized nodule formation was evaluated by Alizarin-Red staining. BMP and EMD up-regulated the osteogenic gene expression. The BMP Group showed significantly higher expression of Collagen-I, III, and V, Alkaline phosphatase and Osteonectin compared to MACS(+)- and OB-Group (p < 0.05; Two-way ANOVA/Bonferroni) with no mineralized nodule formation. Under in-vitro conditions, Emdogain and BMP-2 up-regulate the osteogenic gene expression of stem/progenitor cells. The combination of BMP-2 and Emdogain showed no additive effect and would not be recommended for a combined clinical stimulation. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  9. Low-temperature processed ultrathin TiO2 for efficient planar heterojunction perovskite solar cells

    International Nuclear Information System (INIS)

    Huang, Xiaokun; Hu, Ziyang; Xu, Jie; Wang, Peng; Zhang, Jing; Zhu, Yuejin

    2017-01-01

    Highlights: • An ultrathin and discrete TiO 2 (u-TiO 2 ) was fabricated at low temperature. • High-performance perovskite solar cells based u-TiO 2 was realized. • u-TiO 2 between perovskite and FTO functions as a bridge for electron transport. • u-TiO 2 accelerates electron transfer and alleviates charge recombination. - Abstract: A compact TiO 2 (c-TiO 2 ) layer fabricated by spin coating or spray pyrolysis following a high-temperature sintering is a routine in high-performance planar heterojunction perovskite solar cells. Here, we demonstrate an effective low-temperature approach to fabricate an ultrathin and discrete TiO 2 (u-TiO 2 ) for enhancing photovoltaic performance of perovskite solar cells. Via hydrolysis of low-concentration TiCl 4 solution at 70 °C, u-TiO 2 was grown on a fluorine doped tin oxide (FTO) substrate, forming the electron selective contact with the photoactive CH 3 NH 3 PbI 3 film. The perovskite solar cell using u-TiO 2 achieves an efficiency of 13.42%, which is compared to 13.56% of the device using c-TiO 2 prepared by high-temperature sintering. Cyclic voltammetry, steady-state photoluminescence spectroscopy and electrical impedance spectroscopy were conducted to study interface engineering and charge carrier dynamics. Our results suggest that u-TiO 2 functions as a bridge for electron transport between perovskite and FTO, which accelerates electron transfer and alleviates charge recombination.

  10. Improved performance of dye-sensitized solar cell based on TiO_2 photoanode with FTO glass and film both treated by TiCl_4

    International Nuclear Information System (INIS)

    Li, Jinlun; Zhang, Haiyan; Wang, Wenguang; Qian, Yannan; Li, Zhenghui

    2016-01-01

    The dye-sensitized solar cell (DSSC) based on TiO_2 photoanode with FTO glass and TiO_2 film co-treated by TiCl_4 were fabricated. The effects of TiCl_4 treatment on the photovoltaic performance of the DSSCs were investigated. TiCl_4 treatment of the FTO glass resulted in the formation of a compact TiO_2 thin layer on its surface, which could increase the electron collection efficiency. Meanwhile, TiCl_4 treatment of the TiO_2 film could fill gaps between nanoparticles in the TiO_2 film, leading to better electron transfer. These advantages make the DSSC exhibit a highest conversion efficiency of 3.34% under a simulated solar irradiation with an intensity of 100 mW/cm"2 (1 sun), increased by 38% compared with that of the untreated DSSC.

  11. Alveolar inflammation in cystic fibrosis

    DEFF Research Database (Denmark)

    Ulrich, Martina; Worlitzsch, Dieter; Viglio, Simona

    2010-01-01

    and ceramide accumulation. We sought to investigate CF lung inflammation in the alveoli. METHODS: Lung tissue from 14 CF patients and four healthy individuals was analyzed for numbers of effector cells, elastin and collagen concentrations, inflammatory markers and density of Pseudomonas aeruginosa....... Additionally, desmosine and isodesmosine concentrations were determined in 52 urine specimens from CF patients to estimate the burden of elastase activities in respiratory secretions. RESULTS: Elastin concentration was significantly decreased and collagen significantly increased in CF alveolar tissues...... as compared to age-matched, healthy individuals. Elastin split products were significantly increased in urine samples from patients with CF and correlated inversely with age, indicating local tissue remodelling due to elastin degradation by unopposed proteolytic enzymes. Alveolar inflammation was also...

  12. Hydrogen protects against hyperoxia-induced apoptosis in type II alveolar epithelial cells via activation of PI3K/Akt/Foxo3a signaling pathway.

    Science.gov (United States)

    Wu, Dan; Liang, Mulin; Dang, Hongxing; Fang, Fang; Xu, Feng; Liu, Chengjun

    2018-01-08

    Oxidative stress is regarded as a key regulator in the pathogenesis of prolonged hyperoxia-induced lung injury, which causes injury to alveolar epithelial cells and eventually leads to development of bronchopulmonary dysplasia (BPD). Many studies have shown that hydrogen has a protective effect in a variety of cells. However, the mechanisms by which hydrogen rescues cells from damage due to oxidative stress in BPD remains to be fully elucidated. This study sought to evaluate the effects of hydrogen on hyperoxia-induced lung injury and to investigate the underlying mechanism. Primary type II alveolar epithelial cells (AECIIs) were divided into four groups: control (21% oxygen), hyperoxia (95% oxygen), hyperoxia + hydrogen, and hyperoxia + hydrogen + LY294002 (a PI3K/Akt inhibitor). Proliferation and apoptosis of AECIIs were assessed using MTS assay and flow cytometry (FCM), respectively. Gene and protein expression were detected by quantitative polymerase chain reaction (q-PCR) and western blot analysis. Stimulation with hyperoxia decreased the expression of P-Akt, P- FoxO3a, cyclinD1 and Bcl-2. Hyperoxic conditions increased levels of Bim, Bax, and Foxo3a, which induced proliferation restriction and apoptosis of AECIIs. These effects of hyperoxia were reversed with hydrogen pretreatment. Furthermore, the protective effects of hydrogen were abrogated by PI3K/Akt inhibitor LY294002. The results indicate that hydrogen protects AECIIs from hyperoxia-induced apoptosis by inhibiting apoptosis factors and promoting the expression of anti-apoptosis factors. These effects were associated with activation of the PI3K/Akt/FoxO3a pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. The Omega-3 Fatty Acid Docosahexaenoic Acid Modulates Inflammatory Mediator Release in Human Alveolar Cells Exposed to Bronchoalveolar Lavage Fluid of ARDS Patients

    Directory of Open Access Journals (Sweden)

    Paolo Cotogni

    2015-01-01

    Full Text Available Background. This study investigated whether the 1 : 2 ω-3/ω-6 ratio may reduce proinflammatory response in human alveolar cells (A549 exposed to an ex vivo inflammatory stimulus (bronchoalveolar lavage fluid (BALF of acute respiratory distress syndrome (ARDS patients. Methods. We exposed A549 cells to the BALF collected from 12 ARDS patients. After 18 hours, fatty acids (FA were added as docosahexaenoic acid (DHA, ω-3 and arachidonic acid (AA, ω-6 in two ratios (1 : 2 or 1 : 7. 24 hours later, in culture supernatants were evaluated cytokines (TNF-α, IL-6, IL-8, and IL-10 and prostaglandins (PGE2 and PGE3 release. The FA percentage content in A549 membrane phospholipids, content of COX-2, level of PPARγ, and NF-κB binding activity were determined. Results. The 1 : 2 DHA/AA ratio reversed the baseline predominance of ω-6 over ω-3 in the cell membranes (P < 0.001. The proinflammatory cytokine release was reduced by the 1 : 2 ratio (P < 0.01 to <0.001 but was increased by the 1 : 7 ratio (P < 0.01. The 1 : 2 ratio reduced COX-2 and PGE2 (P < 0.001 as well as NF-κB translocation into the nucleus (P < 0.01, while it increased activation of PPARγ and IL-10 release (P < 0.001. Conclusion. This study demonstrated that shifting the FA supply from ω-6 to ω-3 decreased proinflammatory mediator release in human alveolar cells exposed to BALF of ARDS patients.

  14. First-in-human study and clinical case reports of the alveolar bone regeneration with the secretome from human mesenchymal stem cells.

    Science.gov (United States)

    Katagiri, Wataru; Osugi, Masashi; Kawai, Takamasa; Hibi, Hideharu

    2016-01-15

    Secreted growth factors and cytokines in the conditioned medium from bone marrow-derived mesenchymal stem cells (MSC-CM) have several effects on cell behavior. Our previous studies revealed that MSC-CM enhances bone regeneration by increasing cell mobilization, angiogenesis, and osteogenesis in vitro and in vivo. This clinical study was undertaken to evaluate the safety and use of MSC-CM for alveolar bone regeneration in eight patients who were diagnosed as needing bone augmentation prior to dental implant placement. The protocol of this clinical study was approved by the ethics committee of Nagoya University Hospital. MSC-CM was prepared from conditioned medium from commercially available human bone marrow-derived MSCs. Patients were treated with beta-tricalcium phosphate (β-TCP) or an atelocollagen sponge soaked with MSC-CM. Clinical and radiographic assessments were performed during the follow-up period. Histological assessments were also performed in some cases. Clinical and histological data from patients who underwent the SFE procedure without MSC-CM were also used retrospectively as reference controls. MSC-CM contained several cytokines such as insulin-like growth factor-1, vascular endothelial growth factor, transforming growth factor-β1, and hepatocyte growth factor in relatively low amounts. No systemic or local complications were reported throughout the study. Radiographic evaluation revealed early bone formation in all cases. Histological evaluation also supported the radiographic findings. Furthermore, infiltration of inflammatory cells was scarce throughout the specimens. MSC-CM was used safely and with less inflammatory signs and appears to have great osteogenic potential for regenerative medicine of bone. This is the first in-human clinical study of alveolar bone regeneration using MSC-CM.

  15. Hydrothermal synthesis of 1D TiO2 nanostructures for dye sensitized solar cells

    International Nuclear Information System (INIS)

    Tacchini, I.; Ansón-Casaos, A.; Yu, Youhai; Martínez, M.T.; Lira-Cantu, M.

    2012-01-01

    Highlights: ► Hydrothermal synthesis allows the preparation of different 1D TiO 2 nanostructures easily. ► Nanotubular morphology demonstrates the highest photovoltaic efficiencies in dye sensitized cells (DSCs). ► Morphology at the nanoscale level is as decisive for DSC efficiency as it is TiO 2 crystal structure and surface area. - Abstract: Mono-dimensional titanium oxide nanostructures (multi-walled nanotubes and nanorods) were synthesized by the hydrothermal method and applied to the construction of dye sensitized solar cells (DSCs). First, nanotubes (TiNTs) and nanotubes loaded with titanium oxide nanoparticles (TiNT/NPs) were synthesized with specific surface areas of 253 m 2 /g and 304 m 2 /g, respectively. After that, thermal treatment of the nanotubes at 500 °C resulted in their transformation into the corresponding anatase nanorods (TiNT-Δ and TiNT/NPs-Δ samples). X-ray diffraction and Raman spectroscopy data indicated that titanium oxide in the pristine TiNT and TiNT/NP samples was converted into anatase phase TiO 2 during the heating. Additionally, specific surface areas and water adsorption capacities decreased after the heat treatment due to the sample agglomeration and the collapse of the inner nanotube channels. DSCs were fabricated with the nanotube TiNT and TiNT/NP samples and with the anatase nanorod TiNT-Δ and TiNT/NPs-Δ samples as well. The highest power conversion efficiency of η = 3.12% was obtained for the TiNT sample, despite its lower specific surface compared with the corresponding nanoparticle-loaded sample (TiNT/NP).

  16. Y-doping TiO2 nanorod arrays for efficient perovskite solar cells

    Science.gov (United States)

    Deng, Xinlian; Wang, Yanqing; Cui, Zhendong; Li, Long; Shi, Chengwu

    2018-05-01

    To improve the electron transportation in TiO2 nanorod arrays and charge separation in the interface of TiO2/perovskite, Y-doping TiO2 nanorod arrays with the length of 200 nm, diameter of 11 nm and areal density of 1050 μm-2 were successfully prepared by the hydrothermal method and the influence of Y/Ti molar ratios of 0%, 3%, 5% in the hydrothermal grown solutions on the growth of TiO2 nanorod arrays was investigated. The results revealed that the appropriate Y/Ti molar ratios can increase the areal density of the corresponding TiO2 nanorod arrays and improve the charge separation in the interface of the TiO2/perovskite. The Y-doping TiO2 nanorod array perovskite solar cells with the Y/Ti molar ratio of 3% exhibited a photoelectric conversion efficiency (PCE) of 18.11% along with an open-circuit voltage (Voc) of 1.06 V, short-circuit photocurrent density (Jsc) of 22.50 mA cm-2 and fill factor (FF) of 76.16%, while the un-doping TiO2 nanorod array perovskite solar cells gave a PCE of 16.42% along with Voc of 1.04 V, Jsc of 21.66 mA cm-2 and FF of 72.97%.

  17. Dye-Sensitized Solar Cells with Anatase TiO2 Nanorods Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Ming-Jer Jeng

    2013-01-01

    Full Text Available The hydrothermal method provides an effective reaction environment for the synthesis of nanocrystalline materials with high purity and well-controlled crystallinity. In this work, we started with various sizes of commercial TiO2 powders and used the hydrothermal method to prepare TiO2 thin films. We found that the synthesized TiO2 nanorods were thin and long when smaller TiO2 particles were used, while larger TiO2 particles produced thicker and shorter nanorods. We also found that TiO2 films prepared by TiO2 nanorods exhibited larger surface roughness than those prepared by the commercial TiO2 particles. It was found that a pure anatase phase of TiO2 nanorods can be obtained from the hydrothermal method. The dye-sensitized solar cells fabricated with TiO2 nanorods exhibited a higher solar efficiency than those fabricated with commercial TiO2 nanoparticles directly. Further, triple-layer structures of TiO2 thin films with different particle sizes were investigated to improve the solar efficiency.

  18. Biomimetic Approach to Solar Cells Based on TiO2 Nanotubes

    National Research Council Canada - National Science Library

    Allen, Jan L; Lee, Ivan C; Wolfenstine, Jeff

    2008-01-01

    The goal of this research was to explore the use of nanotube titanium dioxide (TiO2) as an electrode material in dye-sensitized solar cells in order to further the development of solar cell technology...

  19. Reactive oxygen species mediated DNA damage in human lung alveolar epithelial (A549) cells from exposure to non-cytotoxic MFI-type zeolite nanoparticles.

    Science.gov (United States)

    Bhattacharya, Kunal; Naha, Pratap C; Naydenova, Izabela; Mintova, Svetlana; Byrne, Hugh J

    2012-12-17

    Increasing utilization of engineered nanoparticles in the field of electronics and biomedical applications demands an assessment of risk associated with deliberate or accidental exposure. Metal based nanoparticles are potentially most important of all the nanoparticles in terms of health risks. Microporous alumino-silicates and pure silicates named as zeolites and zeo-type materials with variety of structures, chemical compositions, particle sizes and morphologies have a significant number of industrial uses such as in catalysis, sorption and ion-exchange processes. In particular, the nanosized particles due to their unique properties are used in hybrid organic-inorganic materials for photography, photonics, electronics, labeling, imaging, and sensing. The aim of the current study is to investigate pure silica MFI-type zeolites nanoparticles with sizes of 50nm and 100nm (samples MFI-50 and MFI-100) under suspended conditions and their toxicological effects on human lung alveolar (A549) cells under in vitro conditions. Live cell imaging showed that the nanoparticles precipitated from the colloidal suspension of cell culture media as large agglomerates, coming in contact with the cell surface through sedimentation. A cellular proliferative capacity test showed the zeolite nanoparticles to exhibit no significant cytotoxicity below a concentration of 100μg/ml. However, both the MFI-50 and MFI-100 nanoparticles induced high intracellular reactive oxygen species (ROS) generation and elevated mitochondrial membrane potential in the A549 cells over the measured time period of 12h and at concentrations up to ≤50μg/ml. DNA fragmentation analysis using the comet assay showed that the MFI-50 and MFI-100 nanoparticles cause genotoxicity in a concentration dependent manner. Furthermore, the rate at which maximum genomic damage was caused by MFI-100 nanoparticles in the A549 cells was found to be high as compared to the MFI-50 nanoparticles. However, the damage caused by the

  20. Influence of TiCl4 post-treatment condition on TiO2 electrode for enhancement photovoltaic efficiency of dye-sensitized solar cells.

    Science.gov (United States)

    Eom, Tae Sung; Kim, Kyung Hwan; Bark, Chung Wung; Choi, Hyung Wook

    2014-10-01

    Titanium tetrachloride (TiCl4) treatment processed by chemical bath deposition is usually adopted as pre- and post-treatment for nanocrystalline titanium dioxide (TiO2) film deposition in the dye-sensitized solar cells (DSSCs) technology. TiCl4 post-treatment is a widely known method capable of improving the performance of dye-sensitized solar cells. In this work, the effect of TiCl4 post-treatment on the TiO2 electrode is proposed and compared to the untreated film. A TiO2 passivating layer was deposited on FTO glass by RF magnetron sputtering. The TiO2 sol prepared sol-gel method, nanoporous TiO2 upper layer was deposited by screen printing method on the passivating layer. TiCl4 post-treatment was deposited on the substrate by hydrolysis of TiCl4 aqueous solution. Crystalline structure was adjusted by various TiCl4 concentration and dipping time: 20 mM-150 mM and 30 min-120 min. The conversion efficiency was measured by solar simulator (100 mW/cm2). The dye-sensitized solar cell using TiCl4 post-treatment was measured the maximum conversion efficiency of 5.04% due to electron transport effectively. As a result, the DSSCs based on TiCl4 post-treatment showed better photovoltaic performance than cells made purely of TiO2 nanoparticles. The relative DSSCs devices are characterized in terms of short circuit current density, open circuit voltage, fill factor, conversion efficiency.

  1. Rhabdomyosarcoma of the urinary bladder in adults: predilection for alveolar morphology with anaplasia and significant morphologic overlap with small cell carcinoma.

    Science.gov (United States)

    Paner, Gladell P; McKenney, Jesse K; Epstein, Jonathan I; Amin, Mahul B

    2008-07-01

    Rhabdomyosarcoma (RMS) represents the most common malignant soft tissue tumor in children and adolescents with the urinary bladder representing a frequent site. Most of these urinary bladder tumors are embryonal RMS, predominantly the botryoid subtype. RMSs of the urinary bladder in adults are distinctively rare and the subject of only case reports. We report the clinicopathologic features of 5 bladder neoplasms with rhabdomyosarcomatous differentiation in adults and emphasize the differential diagnosis in the adult setting. The patients, 4 men and 1 woman, ranged in age from 23 to 85 years (mean 65.4 y). Gross hematuria was the most common initial symptom, although 2 patients had metastatic disease at presentation. Four cases were pure primary RMSs of the bladder and 1 case was a sarcomatoid urothelial carcinoma with RMS representing the extensive heterologous component. All 5 cases demonstrated a diffuse growth pattern (ie, non-nested), of which 4 cases had nuclear anaplasia (Wilms criteria without the atypical mitotic figure requirement); only 1 case (the sarcomatoid carcinoma) showed obvious rhabdomyoblastic differentiation (ie, strap cells). Three cases were of the alveolar subtype (1 admixed with embryonal histology) and 2 were RMS, not further classified. Microscopically, all tumors had a primitive undifferentiated morphology with cells containing scant cytoplasm, varying round to fusiform nuclei with even chromatin distribution, and frequent mitoses. The degree of morphologic overlap with small cell carcinoma of the bladder, a relatively more common round cell tumor in adults, was striking. The epithelial component of the sarcomatoid carcinoma was high-grade invasive urothelial carcinoma with glandular differentiation. No other case had previous history of bladder cancer or concurrent carcinoma in situ or invasive urothelial carcinoma. All tumors showed immunohistochemical expression for desmin, myogenin, and/or MyoD1. Synaptophysin was performed in 4 cases

  2. Expression of alveolar type II cell markers in acinar adenocarcinomas and adenoid cystic carcinomas arising from segmental bronchi. A study in a heterotopic bronchogenic carcinoma model in dogs.

    Science.gov (United States)

    TenHave-Opbroek, A. A.; Hammond, W. G.; Benfield, J. R.; Teplitz, R. L.; Dijkman, J. H.

    1993-01-01

    The type II alveolar epithelial cell is one of two pluripotential stem cell phenotypes in normal mammalian lung morphogenesis; cells manifesting this phenotype have been found to constitute bronchioloalveolar regions of canine adenocarcinomas. We now studied type II cell expression in canine acinar adenocarcinomas and adenoid cystic (bronchial gland) carcinomas, using the same bronchogenic carcinoma model (subcutaneous bronchial autografts treated with 3-methylcholanthrene). Distinctive features of type II cells are the approximately cuboid cell shape, large and roundish nucleus, immunofluorescent staining of the cytoplasm for the surfactant protein SP-A, and presence of multilamellar bodies or their precursory forms. Cells with these type II cell characteristics were found in the basal epithelial layer of all tumor lesions and in upper layers as far as the lumen, singly or in clusters; they were also found in early invasive carcinomatous lesions but not in bronchial glands or bronchial epithelium before carcinogen exposure. Immunoblots of tumor homogenates showed reactive proteins within size classes of SP-A (28 to 36 kd) or its dimeric form (56 to 72 kd). These findings and those previously reported are consistent with the concept that chemical carcinogenesis in the adult bronchial epithelium may lead to type II cell carcinomas of varying glandular (acinar, adenoidcystic or bronchioloalveolar) growth patterns. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 PMID:8386445

  3. Non-toxic engineered carbon nanodiamond concentrations induce oxidative/nitrosative stress, imbalance of energy metabolism, and mitochondrial dysfunction in microglial and alveolar basal epithelial cells.

    Science.gov (United States)

    Fresta, Claudia G; Chakraborty, Aishik; Wijesinghe, Manjula B; Amorini, Angela M; Lazzarino, Giacomo; Lazzarino, Giuseppe; Tavazzi, Barbara; Lunte, Susan M; Caraci, Filippo; Dhar, Prajnaparamita; Caruso, Giuseppe

    2018-02-14

    Engineered nanoparticles are finding a wide spectrum of biomedical applications, including drug delivery and capacity to trigger cytotoxic phenomena, potentially useful against tumor cells. The full understanding of their biosafety and interactions with cell processes is mandatory. Using microglial (BV-2) and alveolar basal epithelial (A549) cells, in this study we determined the effects of engineered carbon nanodiamonds (ECNs) on cell viability, nitric oxide (NO) and reactive oxygen species (ROS) production, as well as on energy metabolism. Particularly, we initially measured decrease in cell viability as a function of increasing ECNs doses, finding similar cytotoxic ECN effects in the two cell lines. Subsequently, using apparently non-cytotoxic ECN concentrations (2 µg/mL causing decrease in cell number < 5%) we determined NO and ROS production, and measured the concentrations of compounds related to energy metabolism, mitochondrial functions, oxido-reductive reactions, and antioxidant defences. We found that in both cell lines non-cytotoxic ECN concentrations increased NO and ROS production with sustained oxidative/nitrosative stress, and caused energy metabolism imbalance (decrease in high energy phosphates and nicotinic coenzymes) and mitochondrial malfunctioning (decrease in ATP/ADP ratio).These results underline the importance to deeply investigate the molecular and biochemical changes occurring upon the interaction of ECNs (and nanoparticles in general) with living cells, even at apparently non-toxic concentration. Since the use of ECNs in biomedical field is attracting increasing attention the complete evaluation of their biosafety, toxicity and/or possible side effects both in vitro and in vivo is mandatory before these highly promising tools might find the correct application.

  4. Block copolymer directed synthesis of mesoporous TiO 2 for dye-sensitized solar cells

    KAUST Repository

    Nedelcu, Mihaela; Lee, Jinwoo; Crossland, Edward J. W.; Warren, Scott C.; Orilall, M. Christopher; Guldin, Stefan; Hü ttner, Sven; Ducati, Catarina; Eder, Dominik; Wiesner, Ulrich; Steiner, Ullrich; Snaith, Henry J.

    2009-01-01

    The morphology of TiO2 plays an important role in the operation of solid-state dye-sensitized solar cells. By using polyisoprene-block- ethyleneoxide (PI-b-PEO) copolymers as structure directing agents for a sol-gel based synthesis of mesoporous TiO

  5. Electrochemical Characterization of TiO 2 Blocking Layers for Dye-Sensitized Solar Cells

    KAUST Repository

    Kavan, Ladislav; Té treault, Nicolas; Moehl, Thomas; Grä tzel, Michael

    2014-01-01

    Thin compact layers of TiO2 are grown by thermal oxidation of Ti, by spray pyrolysis, by electrochemical deposition, and by atomic layer deposition. These layers are used in dye-sensitized solar cells to prevent recombination of electrons from

  6. Effects of Surface Structure and Chemical Composition of Binary Ti Alloys on Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Ok-Sung Han

    2016-07-01

    Full Text Available Binary Ti alloys containing Fe, Mo, V and Zr were micro-arc oxidized and hydrothermally treated to obtain micro- and nano-porous layers. This study aimed to investigate cell differentiation on micro and micro/nanoporous oxide layers of Ti alloys. The properties of the porous layer formed on Ti alloys were characterized by X-ray diffraction pattern, microstructural and elemental analyses and inductively coupled plasma mass spectrometry (ICP-MS method. The MTT assay, total protein production and alkaline phosphatase (ALPase activity were evaluated using human osteoblast-like cells (MG-63. Microporous structures of micro-arc oxidized Ti alloys were changed to micro/nanoporous surfaces after hydrothermal treatment. Micro/nanoporous surfaces consisted of acicular TiO2 nanoparticles and micron-sized hydroxyapatite particles. From ICP and MTT tests, the Mo and V ions released from porous oxide layers were positive for cell viability, while the released Fe ions were negative for cell viability. Although the micro/nanoporous surfaces led to a lower total protein content than the polished and microporous Ti surfaces after cell incubation for 7 days, they caused higher ALPase activities after 7 days and 14 days of incubation except for V-containing microporous surfaces. The micro/nanoporous surfaces of Ti alloys were more efficient in inducing MG-63 cell differentiation.

  7. High-stability Ti{sup 4+} precursor for the TiO{sub 2} compact layer of dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Qinghua; Cong, Shan; Wang, Hao; Wang, Yun; Dai, Xiao; Zhao, Jie; Sun, Yinghui; Lou, Yanhui; Zou, Guifu, E-mail: zouguifu@suda.edu.cn

    2015-11-30

    Graphical abstract: - Highlights: • We developed an aqueous polymer-assisted deposition method to improve the chemical stability of the TiCl{sub 4} aqueous solution. • The Ti{sup 4+} is encapsulated by the polymer can maintain their initial performances for several months. • The film is dense, smooth and uniform, preparing by this method. • The power conversion efficiency of the DSSC based on P-TiO{sub 2} compact film is about 12.5% higher than that based on H-TiO{sub 2}. - Abstract: A compact layer (blocking layer) can effectively block the direct contact between the fluorine-doped tin oxide (FTO) glass substrate and electrolyte in dye-sensitized solar cells (DSSCs). The TiCl{sub 4} hydrolysis has been widely adopted for preparing the TiO{sub 2} compact layer (H-TiO{sub 2}). However, the TiCl{sub 4} aqueous solution is unstable for its high reactivity. To improve the chemical stability of TiCl{sub 4} aqueous solution, the Ti{sup 4+} is encapsulated by the polymer, polyethyleneimine (PEI). Experimentals show that the Ti-PEI precursor solution can maintain their initial performances for several months. The resulting TiO{sub 2} film (P-TiO{sub 2}) grown by the Ti-PEI precursor is dense, smooth and uniform without any visible and detectable cracks or voids. The P-TiO{sub 2} compact layer is even denser than the H-TiO{sub 2} compact layer, suggesting reducing the electron recombination and prolonging the electron lifetime in dye-sensitized solar cells. Indeed, the electron lifetime of the DSSC based on the P-TiO{sub 2} is 13.15 ms, which is longer than the 10.83 ms based on H-TiO{sub 2}. Meanwhile, the power conversion efficiency of the DSSC based on P-TiO{sub 2} compact film is about 12.5% higher than that based on H-TiO{sub 2}. Therefore, this encapsulation technology can not only improve the stability of the metal ions solution but also meet a large-scale fabrication demand of the TiO{sub 2} compact layer in future DSSCs.

  8. W-doped TiO2 photoanode for high performance perovskite solar cell

    International Nuclear Information System (INIS)

    Liu, Jinwang; Zhang, Jing; Yue, Guoqiang; Lu, Xingwei; Hu, Ziyang; Zhu, Yuejin

    2016-01-01

    Titanium dioxide (TiO 2 ) with dispersed W-doping shows its capability for efficient electron collection from perovskite to TiO 2 in perovskite solar cell. The conduction band (CB) of TiO 2 moves downward (positive shift) with increasing the tungsten (W) content, which enlarges the energy gap between the CB of TiO 2 and the perovskite. Thus, the efficiency of electron injection from perovskite to TiO 2 is increased. Due to the increased electron injection, W-doped TiO 2 (≤0.2% W content) enhances the short-circuit photocurrent (J sc ) of perovskite solar cell and improves the performance of perovskite solar cell. Perovskite solar cell with 0.1% W-doped photoanode obtains the highest power conversion efficiency (η = 10.6%), which shows enhancement by 13% in J sc and by 17% in η, as compared with the undoped TiO 2 perovskite solar cell.

  9. Investigation of in vitro bone cell adhesion and proliferation on Ti using direct current stimulation

    International Nuclear Information System (INIS)

    Bodhak, Subhadip; Bose, Susmita; Kinsel, William C.; Bandyopadhyay, Amit

    2012-01-01

    Our objective was to establish an in vitro cell culture protocol to improve bone cell attachment and proliferation on Ti substrate using direct current stimulation. For this purpose, a custom made electrical stimulator was developed and a varying range of direct currents, from 5 to 25 μA, was used to study the current stimulation effect on bone cells cultured on conducting Ti samples in vitro. Cell–material interaction was studied for a maximum of 5 days by culturing with human fetal osteoblast cells (hFOB). The direct current was applied in every 8 h time interval and the duration of electrical stimulation was kept constant at 15 min for all cases. In vitro results showed that direct current stimulation significantly favored bone cell attachment and proliferation in comparison to nonstimulated Ti surface. Immunochemistry and confocal microscopy results confirmed that the cell adhesion was most pronounced on 25 μA direct current stimulated Ti surfaces as hFOB cells expressed higher vinculin protein with increasing amount of direct current. Furthermore, MTT assay results established that cells grew 30% higher in number under 25 μA electrical stimulation as compared to nonstimulated Ti surface after 5 days of culture period. In this work we have successfully established a simple and cost effective in vitro protocol offering easy and rapid analysis of bone cell–material interaction which can be used in promotion of bone cell attachment and growth on Ti substrate using direct current electrical stimulation in an in vitro model. - Highlights: ► D.C. stimulation was used to enhance in vitro bone cell adhesion and proliferation. ► Cells cultured on Ti were stimulated by using a custom made electrical stimulator. ► Optimization was performed by using a varying range of direct currents ∼ 5 to 25 μA. ► 25 μA stimulation was found most beneficial for promotion of cell adhesion/growth.

  10. ZnO/TiO{sub 2} particles and their solar cell application

    Energy Technology Data Exchange (ETDEWEB)

    Kerli, S., E-mail: suleymankerli@ksu.edu.tr [Department of EnergySystemsEngineering, Faculty of Elbistan Technology, Kahramanmaras SutcuImamUniversity, Kahramanmaras (Turkey); Akgül, Ö., E-mail: omeraakgul@gmail.com [Kahramanmaras Sutcu Imam University, Dept. of Physics, 46100 K.Maras-Turkey (Turkey); Alver, Ü., E-mail: ualver@ktu.edu.tr [Karadeniz Technical University, Dept. of Metallurgical and Materials Eng. 61080, Trabzon-Turkey (Turkey)

    2016-03-25

    ZnO/TiO{sub 2} particles were investigated for dye-sensitized solar cells (DSSC). Nano-structured ZnO particles were produced by the hydrothermal method. TiO{sub 2} (P25) nanoparticles, was bought from the company of Degussa. Crystal structures and morphological properties of particles were examined by XRD and SEM. As an application, dye sensitized solar cells were fabricated from nano-structured produced metal oxide particles. The working electrodes of the DSSCs were obtained by mixture of ZnO and TiO{sub 2} powders. I-V characteristics of the cells were measured by using a solar simulator and the efficiency of the solar cells were obtained by using I-V graphs. ZnO cells sensitized with Ruthenium 535-bisTBA (N719) dyes yield higher efficiencies than corresponding TiO{sub 2} cells. By increasing TiO{sub 2} amount in the mixture of ZnO/TiO{sub 2}, it was observed that efficiencies of cells are getting lower.

  11. Preparation of flexible TiO2 photoelectrodes for dye-sensitized solar cells

    Science.gov (United States)

    Li, Wen-Ren; Wang, Hsiu-Hsuan; Lin, Chia-Feng; Su, Chaochin

    2014-09-01

    Dye-sensitized solar cells (DSSCs) based on nanocrystalline TiO2 photoelectrodes on indium tin oxide (ITO) coated polymer substrates have drawn great attention due to its lightweight, flexibility and advantages in commercial applications. However, the thermal instability of polymer substrates limits the process temperature to below 150 °C. In order to assure high and firm interparticle connection between TiO2 nanocrystals (TiO2-NC) and polymer substrates, the post-treatment of flexible TiO2 photoelectrodes (F-TiO2-PE) by mechanical compression was employed. In this work, Degussa P25 TiO2-NC was mixed with tert-butyl alcohol and DI-water to form TiO2 paste. F-TiO2-PE was then prepared by coating the TiO2 paste onto ITO coated polyethylene terephthalate (PET) substrate using doctor blade followed by low temperature sintering at 120 °C for 2 hours. To study the effect of mechanical compression, we applied 50 and 100 kg/cm2 pressure on TiO2/PET to complete the fabrication of F-TiO2-PE. The surface morphology of F-TiO2-PE was characterized using scanning electron microscopy. The resultant F-TiO2-PE sample exhibited a smooth, crack-free structure indicating the great improvement in the interparticle connection of TiO2-NC. Increase of compression pressure could lead to the increase of DSSC photoconversion efficiency. The best photoconversion efficiency of 4.19 % (open circuit voltage (Voc) = 0.79 V, short-circuit photocurrent density (Jsc) = 7.75 mA/cm2, fill factor (FF) = 0.68) was obtained for the F-TiO2-PE device, which showed great enhancement compared with the F-TiO2-PE cell without compression treatment. The effect of compression in DSSC performance was vindicated by the electrochemical impedance spectroscopy measurement.

  12. Andrographolide antagonizes cigarette smoke extract-induced inflammatory response and oxidative stress in human alveolar epithelial A549 cells through induction of microRNA-218.

    Science.gov (United States)

    Li, Ying-jie; Yu, Chang-hai; Li, Jing-bo; Wu, Xi-ya

    2013-12-01

    Andrographolide is a major bioactive labdane diterpenoid isolated from Andrographis paniculata and has protective effects against cigarette smoke (CS)-induced lung injury. This study was done to determine whether such protective effects were mediated through modulation of microRNA (miR)-218 expression. Therefore, we exposed human alveolar epithelial A549 cells to cigarette smoke extract (CSE) with or without andrographolide pretreatment and measured the level of glutathione, nuclear factor-kappaB (NF-κB) activation, proinflammatory cytokine production, and miR-218 expression. We found that andrographolide pretreatment significantly restored the glutathione level in CSE-exposed A549 cells, coupled with reduced inhibitor κB (IκB)-α phosphorylation and p65 nuclear translocation and interleukin (IL)-8 and IL-6 secretion. The miR-218 expression was significantly upregulated by andrographolide pretreatment. To determine the biological role of miR-218, we overexpressed and downregulated its expression using miR-218 mimic and anti-miR-218 inhibitor, respectively. We observed that miR-218 overexpression led to a marked reduction in IκB-α phosphorylation, p65 nuclear accumulation, and NF-κB-dependent transcriptional activity in CSE-treated A549 cells. In contrast, miR-218 silencing enhanced IκB-α phosphorylation and p65 nuclear accumulation in cells with andrographolide pretreatment and reversed andrographolide-mediated reduction of IL-6 and IL-8 production. In addition, depletion of miR-218 significantly reversed the upregulation of glutathione levels in A549 cells by andrographolide. Taken together, our results demonstrate that andrographolide mitigates CSE-induced inflammatory response in A549 cells, largely through inhibition of NF-κB activation via upregulation of miR-218, and thus has preventive benefits in CS-induced inflammatory lung diseases.

  13. Microglial cells (BV-2) internalize titanium dioxide (TiO2) nanoparticles: toxicity and cellular responses.

    Science.gov (United States)

    Rihane, Naima; Nury, Thomas; M'rad, Imen; El Mir, Lassaad; Sakly, Mohsen; Amara, Salem; Lizard, Gérard

    2016-05-01

    Because of their whitening and photocatalytic effects, titanium dioxide nanoparticles (TiO2-NPs) are widely used in daily life. These NPs can be found in paints, plastics, papers, sunscreens, foods, medicines (pills), toothpastes, and cosmetics. However, the biological effect of TiO2-NPs on the human body, especially on the central nervous system, is still unclear. Many studies have demonstrated that the brain is one of the target organs in acute or chronic TiO2-NPs toxicity. The present study aimed to investigate the effect of TiO2-NPs at different concentrations (0.1 to 200 μg/mL) on murine microglial cells (BV-2) to assess their activity on cell growth and viability, as well as their neurotoxicity. Different parameters were measured: cell viability, cell proliferation and DNA content (SubG1 peak), mitochondrial depolarization, overproduction of reactive oxygen species (especially superoxide anions), and ultrastructural changes. Results showed that TiO2-NPs induced some cytotoxic effects with a slight inhibition of cell growth. Thus, at high concentrations, TiO2-NPs were not only able to inhibit cell adhesion but also enhanced cytoplasmic membrane permeability to propidium iodide associated with a loss of mitochondrial transmembrane potential and an overproduction of superoxide anions. No induction of apoptosis based on the presence of a SubG1 peak was detected. The microscopic observations also indicated that small groups of nanosized particles and micron-sized aggregates were engulfed by the BV-2 cells and sequestered as intracytoplasmic aggregates after 24-h exposure to TiO2-NPs. Altogether, our data show that the accumulation TiO2-NPs in microglial BV-2 cells favors mitochondrial dysfunctions and oxidative stress.

  14. Nanographite-TiO2 photoanode for dye sensitized solar cells

    Science.gov (United States)

    Sharma, S. S.; Sharma, Khushboo; Sharma, Vinay

    2016-05-01

    Nanographite-TiO2 (NG-TiO2) composite was successfully synthesized by the hydrothermal method and its performance as the photoanode for dye-sensitized solar cells (DSSCs) was investigated. Environmental Scanning electron microscope (E-SEM) micrographs show the uniform distribution of TiO2 nanoflowers deposited over nanographite sheets. The average performance characteristics of the assembled cell in terms of short-ciruit current density (JSC), open circuit voltage (VOC), fill factor (FF) and photoelectric conversion efficiency (η) were measured.

  15. Nanographite-TiO_2 photoanode for dye sensitized solar cells

    International Nuclear Information System (INIS)

    Sharma, S. S.; Sharma, Khushboo; Sharma, Vinay

    2016-01-01

    Nanographite-TiO_2 (NG-TiO_2) composite was successfully synthesized by the hydrothermal method and its performance as the photoanode for dye-sensitized solar cells (DSSCs) was investigated. Environmental Scanning electron microscope (E-SEM) micrographs show the uniform distribution of TiO_2 nanoflowers deposited over nanographite sheets. The average performance characteristics of the assembled cell in terms of short-ciruit current density (J_S_C), open circuit voltage (V_O_C), fill factor (FF) and photoelectric conversion efficiency (η) were measured.

  16. Detection of alveolar rhabdomyosarcoma in pleural fluid with immunocytochemistry on cell block and determination of PAX/FKHR fusion mRNA by reverse transcription-polymerase chain reaction.

    Science.gov (United States)

    Sawangpanich, Ruchchadol; Larbcharoensub, Noppadol; Jinawath, Artit; Pongtippan, Atcharaporn; Anurathapan, Usanarat; Hongeng, Suradej

    2011-11-01

    Alveolar rhabdomyosarcoma is a primitive malignant round cell neoplasm, which shows skeletal muscle differentiation. Although their histopathologic and immunohistochemical findings are well known, the cytology, immunocytochemistry and molecular study on pleural effusion have not been well documented. To apply molecular method in the diagnosis and monitoring of alveolar rhabdomyosarcoma. The case of a 14-year-old Thai male, who presented with dyspnea and left pleural effusion. Computed tomography of the chest and abdomen showed a huge heterogeneous enhancing mass at the left retroperitoneum. Pleural fluid cytology showed malignant small round blue cells. Immunocytochemical stains on cell block material showed positive reactivity to vimentin, sarcomeric actin, desmin, MyoD1, myogenin, and CD56 in round cell tumor Reverse transcription-polymerase chain reaction (RT-PCR) demonstrated PAX/FKHR fusion transcript. The patient received chemotherapeutic regimen for advanced-stage rhabdomyosarcoma. Finally, he succumbed to the disease, thirteen months after the diagnosis. Immunocytochemistry on cell block in conjunction with determination of PAX/FKHR fusion mRNA by RT-PCR is a molecular method in the diagnosis and monitoring of alveolar rhabdomyosarcoma inpleural fluid.

  17. Sb₂S₃ surface modification induced remarkable enhancement of TiO₂ core/shell nanowries solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiuqing, E-mail: xqmeng@semi.ac.cn [Research Center for Light Emitting Diodes (LED), Zhejiang Normal University, Jinhua 321004 (China); Wang, Xiaozhou; Zhong, Mianzeng; Wu, Fengmin; Fang, Yunzhang [Research Center for Light Emitting Diodes (LED), Zhejiang Normal University, Jinhua 321004 (China)

    2013-05-01

    This study presents the fabrication of a novel dye-sensitized solar cell with Sb₂S₃-modified TiO₂ nanowire (NW) arrays/TiO₂ nanoparticles (NP) (TiO₂(NWs)/TiO₂(NPs)/Sb₂S₃) as the anodes and N719 dye as the sensitizer. A solar conversion efficiency of 4.91% at 1 sun illumination was achieved for the composite cell, which is markedly higher than the efficiency rates obtained using TiO₂ and TiO₂(NWs)/Sb₂S₃/TiO₂(NPs) NW cells, calculated at 2.36% and 3.11%, respectively. The improved efficiency results from the large surface area of the NPs, as well as the expansion of the light absorption region and high absorption coefficient by Sb₂S₃ surface modification. - Graphical abstract: A novel TiO₂(NWs)/TiO₂(NPs)/Sb₂S₃ dye sensitized solar cells (DSSCs) is fabricated, a solar conversion efficiency of 4.91 % at 1 sun illumination is achieved. Highlights: • We fabricate sandwich structured TiO₂ dye-sensitized solar cells. • The anode of the solar cells consist of Sb₂S₃ modified TiO₂ nanowire arrays/TiO₂ nanopartices. • A solar conversion efficiency of 4.91% at 1 sun illumination is achieved. • The high efficiency results from large surface area and expanded light adsorption of the anode.

  18. Vascular cell responses to ECM produced by smooth muscle cells on TiO{sub 2} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Fangyu [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu (China); Key Lab of Advanced Technology of Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Zhu, Ying [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu (China); Key Lab of Advanced Technology of Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Wuhan Dragonbio Orthopedic Products CO., LTD, 18, Qinglnghe Road, Hongshan District, Wuhan 430065 (China); Li, Xin [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu (China); Key Lab of Advanced Technology of Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Luo, Rifang, E-mail: lrifang@126.com [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu (China); Key Lab of Advanced Technology of Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Tu, Qiufen [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu (China); Key Lab of Advanced Technology of Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Laboratory of Biosensing and Micro Mechatronics, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Jin, E-mail: jinxxwang@263.net [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu (China); Key Lab of Advanced Technology of Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Huang, Nan [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu (China); Key Lab of Advanced Technology of Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China)

    2015-09-15

    Graphical abstract: - Highlights: • TiO{sub 2} nanotubes with the tube diameter of 30 nm via anodic oxidation was prepared. • SMCs on TiO{sub 2} nanotubes presented enhanced extracellular matrix secreting. • ECM prepared via decellularization retained the components: Fn, Ln and collagen. • ECM-covered TiO{sub 2} nanotubes significantly improved the proliferation of ECs. - Abstract: There is an increasing interest in developing new methods to promote biocompatibility of biomedical materials. The TiO{sub 2} nanotubes with the tube diameter of 30 nm were prepared by anodization. The response behavior of the human umbilical vein endothelial cell (HUVEC) and human umbilical artery smooth muscle cell (HUASMC) to these different nanotube sizes was investigated. Compared to the flat Ti, the growth and viability of HUVEC are prohibited, but there was no significant difference of HUASMC on 30 nm TiO{sub 2} nanotubes. In this study, extracellular matrix (ECM) as a complex cellular environment which provides structural support to cells and regulates the cells functions was further used to modify the biological properties of TiO{sub 2} nanotubes. The ECM secreted from HUASMC was successfully deposited onto the 30 nm TiO{sub 2} nanotubes. Moreover, immunofluorescence staining of common ECM components, such as fibronectin, laminin and type IV collagen, also indicated the successful ECM-covering on nanotube surfaces. Interestingly, the surface of ECM-covered TiO{sub 2} nanotubes significantly improved the proliferation of HUVECs in vitro. This suggested that the ECM secreted from HUASMCs on the TiO{sub 2} nanotubular surface could further improve the HUVECs adhesion and proliferation.

  19. High-efficiency perovskite solar cells based on anatase TiO{sub 2} nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yan, E-mail: huangyan@ecust.edu.cn [School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237 (China); Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Wu, Jiamin; Gao, Di [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2016-01-01

    Perovskite solar cells (PSCs) based on one-dimensional anatase TiO{sub 2} nanotube arrays were prepared by using a two-step deposition method to fill the arrays of TiO{sub 2} nanotubes in different lengths with perovskite. The photovoltaic performance of PSCs was found to be significantly dependent on the length of the TiO{sub 2} nanotubes, and the power conversion efficiency decreased as the length of the TiO{sub 2} nanotubes increased from ~ 0.40 μm to ~ 0.65 and then to ~ 0.93 μm. The PSC fabricated with ~ 0.40 μm-long anatase TiO{sub 2} nanotube arrays yielded a power conversion efficiency of 11.3% and a fill factor of 0.68 under illumination of 100 mW/cm{sup 2} AM 1.5G simulated sunlight, which is significantly higher than previously reported solar cells based on 1-D TiO{sub 2} nanostructures. Incident photon-to-current efficiency and electrochemical impedance spectroscopy measurements indicated that longer TiO{sub 2} nanotubes led to higher recombination losses of charge carriers, possibly due to poor filling of the nanotube arrays with perovskite. - Highlights: • 1D anatase TiO{sub 2} nanotubes were used to fabricate perovskite solar cells. • The best efficiency of 11.3% was achieved with ~ 0.40 μm-long TiO{sub 2} nanotubes. • The efficiency of the devices decreased with increasing TiO{sub 2} nanotube lengths.

  20. Alveolar macrophage-epithelial cell interaction following exposure to atmospheric particles induces the release of mediators involved in monocyte mobilization and recruitment

    Directory of Open Access Journals (Sweden)

    Mukae Hiroshi

    2005-08-01

    Full Text Available Abstract Background Studies from our laboratory have shown that human alveolar macrophages (AM and bronchial epithelial cells (HBEC exposed to ambient particles (PM10 in vitro increase their production of inflammatory mediators and that supernatants from PM10-exposed cells shorten the transit time of monocytes through the bone marrow and promote their release into the circulation. Methods The present study concerns co-culture of AM and HBEC exposed to PM10 (EHC-93 and the production of mediators involved in monocyte kinetics measured at both the mRNA and protein levels. The experiments were also designed to determine the role of the adhesive interaction between these cells via the intercellular adhesion molecule (ICAM-1 in the production of these mediators. Results AM/HBEC co-cultures exposed to 100 μg/ml of PM10 for 2 or 24 h increased their levels of granulocyte-macrophage colony-stimulating factor (GM-CSF, M-CSF, macrophage inflammatory protein (MIP-1β, monocyte chemotactic protein (MCP-1, interleukin (IL-6 and ICAM-1 mRNA, compared to exposed AM or HBEC mono-cultures, or control non-exposed co-cultures. The levels of GM-CSF, M-CSF, MIP-1β and IL-6 increased in co-cultured supernatants collected after 24 h exposure compared to control cells (p 10-induced increase in co-culture mRNA expression. Conclusion We conclude that an ICAM-1 independent interaction between AM and HBEC, lung cells that process inhaled particles, increases the production and release of mediators that enhance bone marrow turnover of monocytes and their recruitment into tissues. We speculate that this interaction amplifies PM10-induced lung inflammation and contributes to both the pulmonary and systemic morbidity associated with exposure to air pollution.

  1. Quantum Dot Sensitized Solar Cells Based on TiO2/AgInS2

    Science.gov (United States)

    Pawar, Sachin A.; Jeong, Jae Pil; Patil, Dipali S.; More, Vivek M.; Lee, Rochelle S.; Shin, Jae Cheol; Choi, Won Jun

    2018-05-01

    Quantum dot heterojunctions with type-II band alignment can efficiently separate photogenerated electron-hole pairs and, hence, are useful for solar cell studies. In this study, a quantum dot sensitized solar cell (QDSSC) made of TiO2/AgInS2 is achieved to boost the photoconversion efficiency for the TiO2-based system by varying the AgInS2 layer's thickness. The TiO2 nanorods array film is prepared by using a simple hydrothermal technique. The formation of a AgInS2 QD-sensitized TiO2-nanorod photoelectrode is carried out by successive ionic layer adsorption and reaction (SILAR) technique. The effect of the QD layer on the performance of the solar cell is studied by varying the SILAR cycles of the QD coating. The synthesized electrode materials are characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy and solar cell performances. The results indicate that the nanocrystals have effectively covered the outer surfaces of the TiO2 nanorods. The interfacial structure of quantum dots (QDs)/TiO2 is also investigated, and the growth interface is verified. A careful comparison between TiO2/AgInS2 sensitized cells reveals that the trasfer of electrons and hole proceeds efficiently, the recombination is suppressed for the optimum thickness of the QD layer and light from the entire visible spectrum is utilised. Under AM 1.5G illumination, a high photocurrent of 1.36 mAcm-2 with an improved power conversion efficiency of 0.48% is obtained. The solar cell properties of our photoanodes suggest that the TiO2 nanorod array films co-sensitized by AgInS2 nanoclusters have potential applications in solar cells.

  2. Three-dimensional self-branching anatase TiO_2 nanorods with the improved carrier collection for SrTiO_3-based perovskite solar cells

    International Nuclear Information System (INIS)

    Hu, Yajing; Wang, Chen; Tang, Ying; Huang, Lu; Fu, Jianxun; Shi, Weimin; Wang, Linjun; Yang, Weiguang

    2016-01-01

    The organic–inorganic perovskite solar cells based on ternary oxide SrTiO_3 shows a higher Voc, attributed to its slightly higher conduction band edge and better morphology of absorber material. However, its less efficient carrier collection and limited overall interfacial areas between the absorber material and the electron-transport layer (ETL), dramatically reducing the Jsc. Here, By adjusting the concentrations of the Ti(OBu)_4, we successfully prepared the three-dimensional (3D) self-branching anatase TiO_2 nanorod/SrTiO_3 nanocomposites, and slightly tuned the particle size of SrTiO_3. With the incorporation of the three-dimensional (3D) self-branching anatase TiO_2 nanorod, the Jsc of the device based on SrTiO_3 was highly boosted. The best performing solar cell we obtained exhibited a PCE of 9.99% with a Jsc of 19.48 mA/cm"2. The excellent performance could be ascribed to the improvement of charge carrier collection of SrTiO_3, better surface coverage and crystallinity of CH_3NH_3PbI_3, and enhanced light scattering ability caused by 3D self-branching anatase TiO_2 nanorods. - Highlights: • The three-dimensional (3D) self-branching anatase TiO_2 nanorod/SrTiO_3 nanocomposites were prepared. • The particle sizes of SrTiO_3 can be slightly tuned. • The best performing solar cell we obtained exhibited a PCE of 9.99% with the Jsc of 19.48 mA/cm"2.

  3. Polymer Photovoltaic Cell Using TiO2/G-PEDOT Nanocomplex Film as Electrode

    Directory of Open Access Journals (Sweden)

    F. X. Xie

    2008-01-01

    Full Text Available Using TiO2/G-PEDOT (PEDOT/PSS doped with glycerol nanocomplex film as a substitute for metal electrode in organic photovoltaic cell is described. Indium tin oxide (ITO worked as cathode and TiO2/G-PEDOT nanocomplex works as anode. The thickness of TiO2 layer in nanocomplex greatly affects the act of this nonmetallic electrode of the device. To enhance its performance, this inverted organic photovoltaic cell uses another TiO2 layer as electron selective layer contacted to ITO coated glass substrates. All films made by solution processing techniques are coated on the transparent substrate (glass with a conducting film ITO. The efficiency of this solar cell is compared with the conventional device using Al as electrode.

  4. Biocompatibility of Ir/Ti-oxide coatings: Interaction with platelets, endothelial and smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Habibzadeh, Sajjad [Department of Chemical Engineering, McGill University, Montreal, QC (Canada); Li, Ling [Department of Anatomy and Cell Biology, McGill University, Montreal, QC (Canada); Omanovic, Sasha [Department of Chemical Engineering, McGill University, Montreal, QC (Canada); Shum-Tim, Dominique [Divisions of Cardiac Surgery and Surgical Research, Department of Surgery, McGill University, Montreal, QC (Canada); Davis, Elaine C., E-mail: elaine.davis@mcgill.ca [Department of Anatomy and Cell Biology, McGill University, Montreal, QC (Canada)

    2014-05-01

    Graphical abstract: - Highlights: • Ir/Ti-oxide coated surfaces are characterized by the so-called “cracked-mud” morphology. • 40% Ir in the coating material results in a morphologically uniform coating. • ECs and SMCs showed a desirable response to the Ir/Ti-oxide coated surfaces. • Ir/Ti-oxide coated surfaces are more bio/hemocompatible than the untreated 316L stainless steel. - Abstract: Applying surface coatings on a biomedical implant is a promising modification technique which can enhance the implant's biocompatibility via controlling blood constituents- or/and cell-surface interaction. In this study, the influence of composition of Ir{sub x}Ti{sub 1−x}-oxide coatings (x = 0, 0.2, 0.4, 0.6, 0.8, 1) formed on a titanium (Ti) substrate on the responses of platelets, endothelial cells (ECs) and smooth muscle cells (SMCs) was investigated. The results showed that a significant decrease in platelet adhesion and activation was obtained on Ir{sub 0.2}Ti{sub 0.8}-oxide and Ir{sub 0.4}Ti{sub 0.6}-oxide coatings, rendering the surfaces more blood compatible, in comparison to the control (316L stainless steel, 316L-SS) and other coating compositions. Further, a substantial increase in the EC/SMC surface count ratio after 4 h of cell attachment to the Ir{sub 0.2}Ti{sub 0.8}-oxide and Ir{sub 0.4}Ti{sub 0.6}-oxide coatings, relative to the 316L-SS control and the other coating compositions, indicated high potential of these coatings for the enhancement of surface endothelialization. This indicates the capability of the corresponding coating compositions to promote EC proliferation on the surface, while inhibiting that of SMCs, which is important in cardiovascular stents applications.

  5. Nanostructured Polyelectrolytes Based on SPEEK/TiO2 for Direct Ethanol Fuel Cells (DEFCs

    Directory of Open Access Journals (Sweden)

    José Carlos Dutra Filho

    2014-01-01

    Full Text Available Proton-conducting hybrid membranes consisting of poly(ether ether ketone sulfonated (SPEEK and titanium oxide (TiO2 were prepared using the sol-gel technique for application in direct ethanol fuel cells. The effect from TiO2 incorporation on membrane properties such as ethanol uptake, pervaporation and proton conductivity was investigated. The uptake and permeated flux decreased with increasing content of TiO2. The ethanol permeability was about one order of magnitude smaller than Nafion® 117. FTIR spectra indicated that PEEK was sulfonated and the second degradation temperature of SPEEK58 samples confirmed the titanium oxide incorporation. The proton conductivity in ethanol solution was of the order of 10-3 S cm-1 when 4 or 8 wt% TiO2 were added, and generally increased with addition of TiO2.

  6. One-Dimensional TiO2 Nanostructures as Photoanodes for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Jie Qu

    2013-01-01

    Full Text Available Titanium dioxide (TiO2 is star materials due to its remarkable optical and electronic properties, resulting in various applications, especially in the fields of dye-sensitized solar cells (DSSCs. Photoanode is the most important part of the DSSCs, which help to adsorb dye molecules and transport the injected electrons. The size, structure, and morphology of TiO2 photoanode have been found to show significant influence on the photovoltaic performance of DSSCs. In this paper, we briefly summarize the synthesis and properties of one-dimensional (1D TiO2 nanomaterials (bare 1D TiO2 nanomaterial and 1D hierarchical TiO2 and their photovoltaic performance in DSSCs.

  7. Effect of TiO{sub 2} thickness on nanocomposited aligned ZnO nanorod/TiO{sub 2} for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Saurdi, I., E-mail: saurdy788@gmail.com; Ishak, A. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); UiTM Sarawak Kampus Kota Samarahan Jalan Meranek, Sarawak (Malaysia); Shafura, A. K.; Azhar, N. E. A.; Mamat, M. H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); Malek, M. F.; Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), (Centre for Nano-Science and Nano-Technology), Institute of Science - IOS, Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Alrokayan, A. H. Salman; Khan, Haseeb A. [Department of Biochemistry, College of Science, Bldg. 5, King Saud University (KSU) P.O: 2455 Riyadh 1145 (Saudi Arabia)

    2016-07-06

    The TiO{sub 2} films were deposited on glass substrate at different thicknesses with different deposition frequencies (1, 2, 3 and 4 times) using spin coating technique and their structural properties were investigated. Subsequently, the nanocomposited aligned ZnO nanorods and TiO{sub 2} were formed by deposited the TiO{sub 2} on top of aligned ZnO Nanorod on ITO-coated glass at different thicknesses using the same method of TiO{sub 2} deposited on glass substrate. The nanocomposited aligned ZnO nanorod/TiO{sub 2} were coated with different thicknesses of 900µm, 1815µm, 2710µm, 3620µm and ZnO without TiO{sub 2}. The dye-sensitized solar cells were fabricated from the nanocomposited aligned ZnO nanorod/TiO{sub 2} with thickness of 900µm, 1815µm, 2710µm and 3620µm and ZnO without TiO{sub 2} and their photovoltaic properties of the DSSCs were investigated. From the solar simulator measurement the solar energy conversion efficiency (η) of 2.543% under AM 1.5 was obtained for the ZnO nanorod/TiO{sub 2} photoanode-2710µm Dye-Sensitized solar cell.

  8. Carnitine palmitoyltransferase 1A (CPT1A): a transcriptional target of PAX3-FKHR and mediates PAX3-FKHR–dependent motility in alveolar rhabdomyosarcoma cells

    International Nuclear Information System (INIS)

    Liu, Lingling; Wang, Yong-Dong; Wu, Jing; Cui, Jimmy; Chen, Taosheng

    2012-01-01

    Alveolar rhabdomyosarcoma (ARMS) has a high propensity to metastasize, leading to its aggressiveness and a poor survival rate among those with the disease. More than 80% of aggressive ARMSs harbor a PAX3-FKHR fusion transcription factor, which regulates cell migration and promotes metastasis, most likely by regulating the fusion protein’s transcriptional targets. Therefore, identifying druggable transcription targets of PAX3-FKHR that are also downstream effectors of PAX3-FKHR–mediated cell migration and metastasis may lead to novel therapeutic approaches for treating ARMS. To identify genes whose expression is directly affected by the level of PAX3-FKHR in an ARMS cellular-context, we first developed an ARMS cell line in which PAX3-FKHR is stably down-regulated, and showed that stably downregulating PAX3-FKHR in ARMS cells significantly decreased the cells’ motility. We used microarray analysis to identify genes whose expression level decreased when PAX3-FKHR was downregulated. We used mutational analysis, promoter reporter assays, and electrophoretic mobility shift assays to determine whether PAX3-FKHR binds to the promoter region of the target gene. We used siRNA and pharmacologic inhibitor to downregulate the target gene of PAX3-FKHR and investigated the effect of such downregulation on cell motility. We found that when PAX3-FKHR was downregulated, the expression of carnitine palmitoyltransferase 1A (CPT1A) decreased. We showed that PAX3-FKHR binds to a paired-domain binding-site in the CPT1A promoter region, indicating that CPT1A is a novel transcriptional target of PAX3-FKHR. Furthermore, downregulating CPT1A decreased cell motility in ARMS cells, indicating that CPT1A is a downstream effector of PAX3-FKHR–mediated cell migration and metastasis. Taken together, we have identified CPT1A as a novel transcriptional target of PAX3-FKHR and revealed the novel function of CPT1A in promoting cell motility. CPT1A may represent a novel therapeutic target for

  9. Enhancement of Perovskite Solar Cells Efficiency using N-Doped TiO2 Nanorod Arrays as Electron Transfer Layer.

    Science.gov (United States)

    Zhang, Zhen-Long; Li, Jun-Feng; Wang, Xiao-Li; Qin, Jian-Qiang; Shi, Wen-Jia; Liu, Yue-Feng; Gao, Hui-Ping; Mao, Yan-Li

    2017-12-01

    In this paper, N-doped TiO 2 (N-TiO 2 ) nanorod arrays were synthesized with hydrothermal method, and perovskite solar cells were fabricated using them as electron transfer layer. The solar cell performance was optimized by changing the N doping contents. The power conversion efficiency of solar cells based on N-TiO 2 with the N doping content of 1% (N/Ti, atomic ratio) has been achieved 11.1%, which was 14.7% higher than that of solar cells based on un-doped TiO 2 . To get an insight into the improvement, some investigations were performed. The structure was examined with X-ray powder diffraction (XRD), and morphology was examined by scanning electron microscopy (SEM). Energy dispersive spectrometer (EDS) and Tauc plot spectra indicated the incorporation of N in TiO 2 nanorods. Absorption spectra showed higher absorption of visible light for N-TiO 2 than un-doped TiO 2 . The N doping reduced the energy band gap from 3.03 to 2.74 eV. The photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectra displayed the faster electron transfer from perovskite layer to N-TiO 2 than to un-doped TiO 2 . Electrochemical impedance spectroscopy (EIS) showed the smaller resistance of device based on N-TiO 2 than that on un-doped TiO 2 .

  10. Phase transformations in the reaction cell of TiNi-based sintered systems

    Science.gov (United States)

    Artyukhova, Nadezhda; Anikeev, Sergey; Yasenchuk, Yuriy; Chekalkin, Timofey; Gunther, Victor; Kaftaranova, Maria; Kang, Ji-Hoon; Kim, Ji-Soon

    2018-05-01

    The present work addresses the structural-phase state changes of porous TiNi-based compounds fabricated by reaction sintering (RS) of Ti and Ni powders with Co, Mo, and no additives introduced. The study also emphasizes the features of a reaction cell (RC) during the transition from the solid- to liquid-phase sintering. Mechanisms of phase transformations occurring in the solid phase, involving the low-melting Ti2Ni phase within the RC, have been highlighted. Also, the intermediate Ti2Ni phase had a crucial role to provide both the required RS behavior and modified phase composition of RS samples, and besides, it is found to be responsible for the near-equiatomic TiNi saturation of the melt. Both cobalt and molybdenum additives are shown to cause additional structuring of the transition zone (TZ) at the Ti2Ni‑TiNi interface and broadening of this zone. The impact of Co and Mo on the Ti2Ni phase is evident through fissuring of this phase layer, which is referred to solidified stresses increased in the layer due to post-alloying defects in the structure.

  11. Dye sensitized solar cell applications of CdTiO{sub 3}–TiO{sub 2} composite thin films deposited from single molecular complex

    Energy Technology Data Exchange (ETDEWEB)

    Ehsan, Muhammad Ali [Nanotechnology and Catalysis Centre (NANOCAT), University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Khaledi, Hamid [Department of Chemistry, Faculty of Science, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Pandikumar, Alagarsamy; Huang, Nay Ming [Department of Physics, Faculty of Science, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Arifin, Zainudin [Department of Chemistry, Faculty of Science, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Mazhar, Muhammad, E-mail: mazhar42pk@yahoo.com [Department of Chemistry, Faculty of Science, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)

    2015-10-15

    A heterobimetallic complex [Cd{sub 2}Ti{sub 4}(μ-O){sub 6}(TFA){sub 8}(THF){sub 6}]·1.5THF (1) (TFA=trifluoroacetato, THF=tetrahydrofuran) comprising of Cd:Ti (1:2) ratio was synthesized by a chemical reaction of cadmium (II) acetate with titanium (IV) isopropoxide and triflouroacetic acid in THF. The stoichiometry of (1) was recognized by single crystal X-ray diffraction, spectroscopic and elemental analyses. Thermal studies revealed that (1) neatly decomposes at 450 °C to furnish 1:1 ratio of cadmium titanate:titania composite oxides material. The thin films of CdTiO{sub 3}–TiO{sub 2} composite oxides were deposited at 550 °C on fluorine doped tin oxide coated conducting glass substrate in air ambient. The micro-structure, crystallinity, phase identification and chemical composition of microspherical architectured CdTiO{sub 3}–TiO{sub 2} composite thin film have been determined by scanning electron microscopy, X-ray diffraction, Raman spectroscopy and energy dispersive X-ray analysis. The scope of composite thin film having band gap of 3.1 eV was explored as photoanode for dye-sensitized solar cell application. - Graphical abstarct: Microspherical designed CdTiO{sub 3}–TiO{sub 2} composite oxides photoanode film has been fabricated from single source precursor [Cd{sub 2}Ti{sub 4}(μ-O){sub 6}(TFA){sub 8}(THF){sub 6}]·1.5THF via aerosol assisted chemical vapor deposition technique for dye sensitized solar cell application. - Highlights: • Synthesis and characterization of a heterobimetallic Cd–Ti complex. • Fabrication of CdTiO{sub 3}–TiO{sub 2} thin film photoelectrode. • Application as dye sensitized photoanode for solar application.

  12. Exposure to TiO2 nanoparticles increases Staphylococcusaureusinfection of HeLa cells

    Science.gov (United States)

    Xu, Yan; Wei, Ming-Tzo; Walker, Stephen. G.; Wang, Hong Zhan; Gondon, Chris; Brink, Peter; Guterman, Shoshana; Zawacki, Emma; Applebaum, Eliana; Rafailovich, Miriam; Ou-Yang, H. Daniel; Mironava, Tatsiana

    TiO2 is one of the most common nanoparticles in industry from food additives to energy generation. Even though TiO2 is also used as an anti-bacterial agent in combination with UV, we found that, in the absence of UV, exposure of HeLa cells to TiO2 nanoparticles largely increased their risk of bacterial invasion. HeLa cells cultured with low dosage rutile and anatase TiO2 nanoparticles (0.1 mg/ml) for 24 hrs prior to exposure to bacteria had 350% and 250% respectively more bacteria infected per cell. The increase was attributed to increased LDH leakage, and changes in the mechanical response of the cell membrane. On the other hand, macrophages exposed to TiO2 particles ingested 40% fewer bacteria, further increasing the risk of infection. In combination, these two factors raise serious concerns regarding the impact of exposure to TiO2 nanoparticles on the ability of organisms to resist bacterial infection.

  13. Biocompatibility of Ir/Ti-oxide coatings: Interaction with platelets, endothelial and smooth muscle cells

    Science.gov (United States)

    Habibzadeh, Sajjad; Li, Ling; Omanovic, Sasha; Shum-Tim, Dominique; Davis, Elaine C.

    2014-05-01

    Applying surface coatings on a biomedical implant is a promising modification technique which can enhance the implant's biocompatibility via controlling blood constituents- or/and cell-surface interaction. In this study, the influence of composition of IrxTi1-x-oxide coatings (x = 0, 0.2, 0.4, 0.6, 0.8, 1) formed on a titanium (Ti) substrate on the responses of platelets, endothelial cells (ECs) and smooth muscle cells (SMCs) was investigated. The results showed that a significant decrease in platelet adhesion and activation was obtained on Ir0.2Ti0.8-oxide and Ir0.4Ti0.6-oxide coatings, rendering the surfaces more blood compatible, in comparison to the control (316L stainless steel, 316L-SS) and other coating compositions. Further, a substantial increase in the EC/SMC surface count ratio after 4 h of cell attachment to the Ir0.2Ti0.8-oxide and Ir0.4Ti0.6-oxide coatings, relative to the 316L-SS control and the other coating compositions, indicated high potential of these coatings for the enhancement of surface endothelialization. This indicates the capability of the corresponding coating compositions to promote EC proliferation on the surface, while inhibiting that of SMCs, which is important in cardiovascular stents applications.

  14. Titanium Dioxide (TiO2) Dye-Sensitized Solar Cells

    Science.gov (United States)

    Alseadi, Anwar Abdulaziz

    With the increasing global energy consumption and diminishing fossil fuels, various renewable and sustainable energies have been harvested in past decades and related devices have been fabricated. Dye-sensitized solar cells (DSSCs) are the most efficient third-generation solar cells to harvest solar energy into electricity directly. Titanium dioxide (TiO2) based DSSCs were invented in 1988 and have attracted more and more attention since then because of low-cost and high efficiency. TiO2 nanoparticles are one kind of popular anode materials of DSSC because of stability, abundance, environment safety, non-toxicity, and excellent photovoltaic properties. In the project, TiO2 nanoparticles with different crystallographic sizes were produced by ball-milling. Physical properties of the produced TiO 2 nanoparticles were characterized by X-ray powder diffraction, UV-visible spectroscopy, and Raman scattering. TiO2-based DSSCs were fabricated and their photovoltaic performances were tested. The effects of TiO2 layer thickness, crystallographic size, and microsphere fillings were investigated. The project enriched our understanding of TiO2-based DSSCs.

  15. Nanostructured Polyelectrolytes Based on SPEEK/TiO2 for Direct Ethanol Fuel Cells (DEFCs)

    OpenAIRE

    Dutra Filho, José Carlos; Santos, Tamirys Rodrigues dos; Gomes, Aílton de Souza

    2014-01-01

    Proton-conducting hybrid membranes consisting of poly(ether ether ketone) sulfonated (SPEEK) and titanium oxide (TiO2) were prepared using the sol-gel technique for application in direct ethanol fuel cells. The effect from TiO2 incorporation on membrane properties such as ethanol uptake, pervaporation and proton conductivity was investigated. The uptake and permeated flux decreased with increasing content of TiO2. The ethanol permeability was about one order of magnitude smaller than Nafion® ...

  16. Sputter Deposited TiOx Thin-Films as Electron Transport Layers in Organic Solar Cells

    DEFF Research Database (Denmark)

    Mirsafaei, Mina; Bomholt Jensen, Pia; Lakhotiya, Harish

    transparency and favorable energy-level alignment with many commonly used electron-acceptor materials. There are several methods available for fabricating compact TiOx thin-films for use in organic solar cells, including sol-gel solution processing, spray pyrolysis and atomic-layer deposition; however...... of around 7%, by incorporating sputter deposited TiOx thin-films as electron-transport and exciton-blocking layers. In the work, we report on the effect of different TiOx deposition temperatures and thicknesses on the organic-solar-cell device performance. Besides optical characterization, AFM and XRD...... analyses are performed to characterize the morphology and crystal structure of the films, and external quantum efficiency measurements are employed to shed further light on the device performance. Our study presents a novel method for implementation of TiOx thin-films as electron-transport layer in organic...

  17. Dye-Sensitized Solar Cells Based on Bi4Ti3O12

    Directory of Open Access Journals (Sweden)

    Zeng Chen

    2011-01-01

    Full Text Available Bismuth titanate (Bi4Ti3O12 particles were synthesized by hydrothermal treatment and nanoporous thin films were prepared on conducting glass substrates. The structures and morphologies of the samples were examined with X-ray diffraction and scanning electron microscope (SEM. Significant absorbance spectra emerged in visible region which indicated the efficient sensitization of Bi4Ti3O12 with N3 dye. Surface photovoltaic properties of the samples were investigated by surface photovoltage. The results further indicate that N3 can extend the photovoltaic response range of Bi4Ti3O12 nanoparticles to the visible region, which shows potential application in dye-sensitized solar cell. As a working electrode in dye-sensitized solar cells (DSSCs, the overall efficiency reached 0.48% after TiO2 modification.

  18. Pulmonary alveolar microlithiliasis

    International Nuclear Information System (INIS)

    Fasihuddin, S.; Alawi, Malak H.; Abdulshakoor, Bothania M.

    2004-01-01

    We report a patient with plmonary alveolar microlithiliasis who was admitted to King Abdul-Aziz Hospital, Makkah, Kingdom of Saudi Arabia with chest pain, shortness of breath dry cough and swelling of lower limbs.The patient underwent chest radiolgraphs and computerized tomography scan showing multiple diffuse, almost symmetrical bilateral micronodulor opacities of calicific density. The diagnosis was confirmed after percuraneous lung biopsy from the patient. Cardiokinetics, diuretics and oxygen were administerd with slight improvement. (author)

  19. Mechanisms underlying the redistribution of particles among the lung's alveolar macrophages during alveolar phase clearance

    Energy Technology Data Exchange (ETDEWEB)

    Lehnert, B.E.; Oritz, J.B.; Steinkamp, J.A.; Tietjen, G.L.; Sebring, R.J. (Los Alamos National Lab., NM (United States)); Oberdorster, G. (Rochester Univ., NY (United States))

    1991-01-01

    In order to obtain information about the particle redistribution phenomenon following the deposition of inhaled particles, as well as to obtain information about some of the mechanisms that may be operable in the redistribution of particles, lavaged lung free cell analyses and transmission electron microscopic (TEM) analyses of lung tissue and were performed using lungs from rats after they were subchronically exposed to aerosolized dioxide (TiO{sub 2}). TEM analyses indicated that the in situ autolysis of particle-containing Alveolar Macropages (AM) is one important mechanism involved in the redistribution of particles. Evidence was also obtained that indicated that the engulfment of one particle-containing phagocyte by another phagocyte also occurs. Another prominent mechanism of the particle redistribution phenomenon may be the in situ proliferation of particle-laden AM. We used the macrophage cell line J774A.1 as a surrogate for AM to investigate how different particulate loads in macrophages may affect their abilities to proliferate. These in vitro investigations indicated that the normal rate of proliferation of macrophages is essentially unaffected by the containment of relatively high particulate burdens. Overall, the results of our investigations suggest that in situ autolysis of particle-containing AM and the rephagocytosis of freed particles by other phagocytes, the phagocytosis of effete and disintegrating particle-containing phagocytes by other AM, and the in situ division of particle-containing AM are likely mechanisms that underlie the post-depositional redistribution of particles among the lung's AM during alveolar phase clearance. 19 refs., 8 figs., 2 tabs.

  20. Proteinosis alveolar pulmonar

    Directory of Open Access Journals (Sweden)

    Concepción Sánchez Infante

    2011-12-01

    Full Text Available La proteinosis alveolar pulmonar es una enfermedad respiratoria crónica, caracterizada por alteración en el metabolismo del surfactante, lo que determina su acumulación anormal en el espacio alveolar. Es una enfermedad extremadamente rara. Se han reportado solamente 500 casos en la literatura. Se describió por primera vez en 1958. Se presenta un caso de proteinosis alveolar pulmonar en un lactante de 2 meses, con desnutrición proteico energética, que ingresa por dificultad respiratoria e hipoxemia, y, con imágenes radiológicas de tipo retículo-nodulillar, en vidrio deslustrado, en el cual se plantea inicialmente el diagnóstico de bronconeumonía. Ante la evolución desfavorable y no respuesta al tratamiento, se realizó un estudio para descartar enfermedades pulmonares crónicas. El paciente fallece y se confirma el diagnóstico por anatomía patológica. Se realiza una revisión del tema.

  1. Pulmonary alveolar microlithiasis

    International Nuclear Information System (INIS)

    Vallejo, Franco Javier; Vallejo, Alejandro; Parra, Maximiliano

    2007-01-01

    Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by the diffuse and bilateral presence of calcium phosphate microlite in the alveolar spaces. The progression of this potentially lethal disease is show and most of the patients remain asymptomatic during years or decades, resulting in a show deterioration of the pulmonary function. The typical finding of the sand storm in the chest X-ray is characteristic of this entity. Mutations in the SLC34A2 gene that does the coding for the type II co-transporter of sodium phosphate were identified as responsible for this disease. Of the almost 600 cases, only 6 have been reported in Colombia. We are presenting a case of pulmonary alveolar microlite in a 27 year old man, with progressive respiratory distress whose diagnosis was made by the X-ray findings and confirmed by trans bronchial biopsy. In the 2 years follow-up, shows evolution towards deterioration of his respiratory function making him a candidate for lung transplantation.

  2. Copper doping enhanced the oxidative stress-mediated cytotoxicity of TiO2 nanoparticles in A549 cells.

    Science.gov (United States)

    Ahmad, J; Siddiqui, M A; Akhtar, M J; Alhadlaq, H A; Alshamsan, A; Khan, S T; Wahab, R; Al-Khedhairy, A A; Al-Salim, A; Musarrat, J; Saquib, Q; Fareed, M; Ahamed, M

    2018-05-01

    Physicochemical properties of titanium dioxide nanoparticles (TiO 2 NPs) can be tuned by doping with metals or nonmetals. Copper (Cu) doping improved the photocatalytic behavior of TiO 2 NPs that can be applied in various fields such as environmental remediation and nanomedicine. However, interaction of Cu-doped TiO 2 NPs with human cells is scarce. This study was designed to explore the role of Cu doping in cytotoxic response of TiO 2 NPs in human lung epithelial (A549) cells. Characterization data demonstrated the presence of both TiO 2 and Cu in Cu-doped TiO 2 NPs with high-quality lattice fringes without any distortion. The size of Cu-doped TiO 2 NPs (24 nm) was lower than pure TiO 2 NPs (30 nm). Biological results showed that both pure and Cu-doped TiO 2 NPs induced cytotoxicity and oxidative stress in a dose-dependent manner. Low mitochondrial membrane potential and higher caspase-3 enzyme (apoptotic markers) activity were also observed in A549 cells exposed to pure and Cu-doped TiO 2 NPs. We further observed that cytotoxicity caused by Cu-doped TiO 2 NPs was higher than pure TiO 2 NPs. Moreover, antioxidant N-acetyl cysteine effectively prevented the reactive oxygen species generation, glutathione depletion, and cell viability reduction caused by Cu-doped TiO 2 NPs. This is the first report showing that Cu-doped TiO 2 NPs induced cytotoxicity and oxidative stress in A549 cells. This study warranted further research to explore the role of Cu doping in toxicity mechanisms of TiO 2 NPs.

  3. TiO{sub 2} nanotubes and mesosponges. Towards solar cells and related applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Doohun

    2010-07-06

    There has been a considerable interest in nano-oxide materials owing to their remarkable characteristics in electrical, optical and chemical properties which have led to various applications. Among the various oxides, titanium dioxide (TiO{sub 2}) is the most widely studied material, because of its promising applications in photocatalysts, biomedical devices and solar cells with its non-toxic nature, high chemical stability and relatively low production cost. However, photoinduced processes in TiO{sub 2} typically require UV light irradiation due to its comparably high bandgap energy. This does not allow an efficient use of solar energy, because only 2{proportional_to}5% of the solar spectrum are in the UV range. Therefore, considerable efforts have been made to engineer the bandgap by doping of TiO{sub 2} photoelectrode with suitable species or by sensitization with visible light absorbers to enhance the solar light conversion efficiency in the visible range. In many applications, TiO{sub 2} layers have been prepared by a variety of techniques such as sol-gel, e-beam evaporation, magnetron sputtering, anodization, etc. Especially, anodization is a simple and exquisite method for synthesizing TiO{sub 2} nanostructures, and thus anodization is a promising method that can be considered as a convenient and cost-effective process. Since the last decade, a significant body of work on anodization has been dedicated to form self-organized and highly ordered nanotube oxide layers. Their morphologies (e.g. nanotube length, diameter and geometrical modification) and crystallinities (e.g. amorphous, anatase and rutile) can be tuned and adjusted to their applications by tailoring the anodization and annealing conditions. In this work, the electrochemical single step anodization process in fluoride-containing electrolytes is employed to prepare vertically oriented TiO{sub 2} nanotubes. Furthermore, we introduce an entirely novel anodization approach to prepare a mesoporous Ti

  4. Role of alveolar epithelial Early growth response-1 (Egr-1) in CD8+ T Cell mediated Lung Injury

    OpenAIRE

    Ramana, Chilakamarti V.; Cheng, Guang-Shing; Kumar, Aseem; Kwon, Hyung- Joo; Enelow, Richard I.

    2009-01-01

    Influenza infection of the distal airways results in severe lung injury, a considerable portion of which is immunopathologic and attributable to the host responses. We have used a mouse model to specifically investigate the role of antiviral CD8+ T cells in this injury, and have found that the critical effector molecule is TNF-α expressed by the T cells upon antigen recognition. Interestingly, the immunopathology which ensues is characterized by significant accumulation of host inflammatory c...

  5. ZnO@TiO2 Architectures for a High Efficiency Dye-Sensitized Solar Cell

    International Nuclear Information System (INIS)

    Lei, Jianfei; Liu, Shuli; Du, Kai; Lv, Shijie; Liu, Chaojie; Zhao, Lingzhi

    2015-01-01

    Graphical Abstract: A fast and improved electrochemical process was reported to fabricate ZnO@TiO 2 heterogeneous architectures with enhanced power conversion efficiency (ƞ = 2.16%). This paper focuses on achieving high dye loading via binding noncorrosive TiO 2 nanocones to the outermost layer, while retaining the excellent electron transport behavior of the ZnO-based internal layer. Display Omitted -- Highlights: • Nanoconic TiO 2 particles are loaded on the surface of aligned ZnO NWs successfully by a liquid phase deposition method. • ZnO@TiO 2 architectures exhibit high efficiency of the DSSCs. -- Abstract: Instead of the spin coating step, an improved electrochemical process is reported in this paper to prepare ZnO seeded substrates and ZnO nanowires (ZnO NWs). Vertically aligned ZnO NWs are deposited electrochemically on the ZnO seeded substrates directly forming backbones for loading nanoconic TiO 2 particles, and hence ZnO@TiO 2 heterogeneous architectures are obtained. When used as photoanode materials of the dye-sensitized solar cells (DSSCs), ZnO@TiO 2 architectures exhibit enhanced power conversion efficiency (PCE) of the DSSCs. Results of the solar cell testing show that addition of TiO 2 shells to the ZnO NWs significantly increases short circuit current (from 2.6 to 4.7 mA cm −2 ), open circuit voltage (from 0.53 V to 0.77 V) and fill factor (from 0.30 to 0.59). The PCE jumped from 0.4% for bare ZnO NWs to 2.16% for ZnO@TiO 2 architectures under 100 mW cm −2 of AM 1.5 G illumination

  6. Solution-Processed Ultrathin TiO2 Compact Layer Hybridized with Mesoporous TiO2 for High-Performance Perovskite Solar Cells.

    Science.gov (United States)

    Jeong, Inyoung; Park, Yun Hee; Bae, Seunghwan; Park, Minwoo; Jeong, Hansol; Lee, Phillip; Ko, Min Jae

    2017-10-25

    The electron transport layer (ETL) is a key component of perovskite solar cells (PSCs) and must provide efficient electron extraction and collection while minimizing the charge recombination at interfaces in order to ensure high performance. Conventional bilayered TiO 2 ETLs fabricated by depositing compact TiO 2 (c-TiO 2 ) and mesoporous TiO 2 (mp-TiO 2 ) in sequence exhibit resistive losses due to the contact resistance at the c-TiO 2 /mp-TiO 2 interface and the series resistance arising from the intrinsically low conductivity of TiO 2 . Herein, to minimize such resistive losses, we developed a novel ETL consisting of an ultrathin c-TiO 2 layer hybridized with mp-TiO 2 , which is fabricated by performing one-step spin-coating of a mp-TiO 2 solution containing a small amount of titanium diisopropoxide bis(acetylacetonate) (TAA). By using electron microscopies and elemental mapping analysis, we establish that the optimal concentration of TAA produces an ultrathin blocking layer with a thickness of ∼3 nm and ensures that the mp-TiO 2 layer has a suitable porosity for efficient perovskite infiltration. We compare PSCs based on mesoscopic ETLs with and without compact layers to determine the role of the hole-blocking layer in their performances. The hybrid ETLs exhibit enhanced electron extraction and reduced charge recombination, resulting in better photovoltaic performances and reduced hysteresis of PSCs compared to those with conventional bilayered ETLs.

  7. Modifying TiO{sub 2} surface architecture by oxygen plasma to increase dye sensitized solar cell efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Rajmohan, Gayathri Devi [Institute for Frontier Materials, Deakin University, Geelong Waurn Ponds, Victoria 3216 (Australia); Dai, Xiujuan J., E-mail: jane.dai@deakin.edu.au [Institute for Frontier Materials, Deakin University, Geelong Waurn Ponds, Victoria 3216 (Australia); Tsuzuki, Takuya; Lamb, Peter R. [Institute for Frontier Materials, Deakin University, Geelong Waurn Ponds, Victoria 3216 (Australia); Plessis, Johan du [School of Applied Sciences, RMIT University, GPO Box 2476 V, Melbourne, Victoria 3001 (Australia); Huang, Fuzhi; Cheng, Yi-Bing [Department of Materials Engineering, Monash University, Melbourne, Victoria 3800 (Australia)

    2013-10-31

    Oxygen plasma treatment of TiO{sub 2} films has been used to improve the efficiency of dye sensitized solar cells. Both a commercial TiO{sub 2} sample and a TiO{sub 2} thin film synthesized by a sol-gel technique were treated using a custom built inductively coupled plasma apparatus. X-ray photoelectron spectroscopy revealed that oxygen-plasma treatment increased the number of oxygen functional groups (hydroxyl groups) and introduced some Ti{sup 3+} species on the surface of TiO{sub 2}. A sample solar cell with plasma treated TiO{sub 2} showed an overall solar-to-electricity conversion efficiency of 4.3%, about a 13% increase over untreated TiO{sub 2}. The photon conversion efficiency for the plasma treated TiO{sub 2} was 34% higher than untreated TiO{sub 2}. This enhanced cell-performance is partly due to increased dye adsorption from an increase in surface oxygen functional groups and also may be partly due to Ti{sup 3+} states on the surface of TiO{sub 2}. - Highlights: • Oxygen plasma is used to generate hydroxyl groups on the surface of TiO{sub 2} • Parallel study was conducted using a spin coated TiO{sub 2} and a Commercial TiO{sub 2} film. • The plasma functionalization caused increased dye uptake. • Some species in Ti{sup 3+} state are also generated after oxygen plasma. • Dye sensitised solar cell with functionalised electrode showed improved efficiency.

  8. Hybrid TiO2: polymer photovoltaic cells made from a titanium oxide precursor

    NARCIS (Netherlands)

    Slooff, L.H.; Wienk, M.M.; Kroon, J.M.

    2004-01-01

    Hybrid TiO2:polymer photovoltaic cells were made from mixtures of titanium(IV) isopropoxide and poly[2-methoxy-5-(3',7'-dimethyloctyl)-p-phenylene vinylene] (MDMO-PPV) or poly(3-octyl thiophene) (P3OT) via hydrolysis in air. Cells were made with varying titanium(IV) isopropoxide:polymer ratios.

  9. Validation and utilization of a TFE3 break-apart FISH assay for Xp11.2 translocation renal cell carcinoma and alveolar soft part sarcoma.

    Science.gov (United States)

    Pradhan, Dinesh; Roy, Somak; Quiroga-Garza, Gabriela; Cieply, Kathleen; Mahaffey, Alyssa L; Bastacky, Sheldon; Dhir, Rajiv; Parwani, Anil V

    2015-09-29

    Xp11.2 or TFE3 translocation renal cell carcinomas (RCC) and alveolar soft part sarcoma (ASPS) are characterized by chromosome translocations involving the Xp11.2 breakpoint resulting in transcription factor TFE3 gene fusions. The most common translocations documented in TFE3 RCCs are t(X;1) (p11.2;q21) and t(X;17) (p11.2;q25) which leads to fusion of TFE3 gene on Xp11.2 with PRCC or ASPL respectively. TFE3 immunohistochemistry (IHC) has been inconsistent over time due to background staining problems in part related to fixation issues. Karyotyping to detect TFE3 gene rearrangement requires typically unavailable fresh tissue. Reverse transcriptase-polymerase chain reaction (RT-PCR) is generally very challenging due to degradation of RNA in archival material. The study objective was to develop and validate a TFE3 break-apart fluorescence in situ hybridization (FISH) assay to confirm Xp11 translocation RCCs and ASPS. Representative sections of formalin-fixed paraffin-embedded tissue blocks were selected in 40 possible cases. Approximately 60 tumor cells were analyzed in the targeted region. The validation of TFE3 FISH was done with 11 negative and two positive cases. Cut off for a positive result was validated as >7.15 % positive nuclei with any pattern of break-apart signals. FISH evaluation was done blinded of the immunohistochemical or karyotype data. Three out of forty cases were positive for the TFE3 break-apart signals by FISH. The negative cases were reported as clear cell RCC with papillary features (10), clear cell RCC with sarcomatoid areas (2), Papillary RCC with clear cell areas (9), Chromophobe RCC (2), RCC, unclassified type (3) and renal medullary carcinoma (1). 3 of the negative cases were consultation cases for renal tumor with unknown histology. Seven negative cases were soft tissue tumor suspicious for ASPS. Our study validates the utility of TFE3 break-apart FISH on formalin-fixed paraffin-embedded tissue sections for diagnosis and confirmation of

  10. Synthesis and characterization of Nafion/TiO2 nanocomposite membrane for proton exchange membrane fuel cell.

    Science.gov (United States)

    Kim, Tae Young; Cho, Sung Yong

    2011-08-01

    In this study, the syntheses and characterizations of Nafion/TiO2 membranes for a proton exchange membrane fuel cell (PEMFC) were investigated. Porous TiO2 powders were synthesized using the sol-gel method; with Nafion/TiO2 nanocomposite membranes prepared using the casting method. An X-ray diffraction analysis demonstrated that the synthesized TiO2 had an anatase structure. The specific surface areas of the TiO2 and Nafion/TiO2 nanocomposite membrane were found to be 115.97 and 33.91 m2/g using a nitrogen adsorption analyzer. The energy dispersive spectra analysis indicated that the TiO2 particles were uniformly distributed in the nanocomposite membrane. The membrane electrode assembly prepared from the Nafion/TiO2 nanocomposite membrane gave the best PEMFC performance compared to the Nafion/P-25 and Nafion membranes.

  11. Improving the Osteoblast Cell Adhesion on Electron Beam Controlled TiO2 Nanotubes

    Directory of Open Access Journals (Sweden)

    Sung Wook Yoon

    2014-01-01

    Full Text Available Here we investigate the osteogenesis and synostosis processes on the surface-modified TiO2 nanotubes via electron beam irradiation. The TiO2 nanotubes studied were synthesized by anodization process under different anodizing voltage. For the anodization voltage of 15, 20, and 25 V, TiO2 nanotubes with diameters of 59, 82, and 105 nm and length of 115, 276, and 310 nm were obtained, respectively. MC3T3-E1 osteoblast cell line was incubated on the TiO2 nanotubes to monitor the change in the cell adhesion before and after the electron beam irradiation. We observe that the electron beam irradiation affects the number of surviving osteoblast cells as well as the cultivation time. In particular, the high adhesion rate of 155% was obtained when the osteoblast cells were cultivated for 2 hours on the TiO2 nanotube, anodized under 20 V, and irradiated with 5,000 kGy of electron beam.

  12. Deliberate Design of TiO2 Nanostructures towards Superior Photovoltaic Cells.

    Science.gov (United States)

    Sun, Ziqi; Liao, Ting; Sheng, Liyuan; Kou, Liangzhi; Kim, Jung Ho; Dou, Shi Xue

    2016-08-01

    TiO2 nanostructures are being sought after as flexibly utilizable building blocks for the fabrication of the mesoporous thin-film photoelectrodes that are the heart of the third-generation photovoltaic devices, such as dye-sensitized solar cells (DSSCs), quantum-dot-sensitized solar cells (QDSSCs), and the recently promoted perovskite-type solar cells. Here, we report deliberate tailoring of TiO2 nanostructures for superior photovoltaic cells. Morphology engineering of TiO2 nanostructures is realized by designing synthetic protocols in which the precursor hydrolysis, crystal growth, and oligomer self-organization are precisely controlled. TiO2 nanostructures in forms varying from isolated nanocubes, nanorods, and cross-linked nanorods to complex hierarchical structures and shape-defined mesoporous micro-/nanostructures were successfully synthesized. The photoanodes made from the shape-defined mesoporous TiO2 microspheres and nanospindles presented superior performances, owing to the well-defined overall shapes and the inner ordered nanochannels, which allow not only a high amount of dye uptake, but also improved visible-light absorption. This study provides a new way to seek an optimal synthetic protocol to meet the required functionality of the nanomaterials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Cytotoxic and Apoptosis-Inducing Activity of Plants from the Family Asparagaceae in Relation to Human Alveolar Adenocarcinoma Cells

    Directory of Open Access Journals (Sweden)

    Y.N. Kamalova

    2016-06-01

    Full Text Available Cancer is known as the second major mortality cause. The number of new cases is increasing every year. Thus, it is urgent for scientists to search for alternative drugs with selective antitumor action and minimal side effects. It is known that some plant metabolites exhibit antioxidant, cytotoxic, and antitumor activity, while at the same time being less toxic than modern allopathic drugs. In this work, we have investigated the cytotoxic and apoptosis-inducing effects of extracts obtained from plants of the family Asparagaceae on A549 human lung adenocarcinoma cells. The analysis has been performed using flow cytofluorometry. If extracts showed cytotoxicity, the apoptosis-inducing action has been evaluated at the concentration of 50 μg/mL; in other cases, the analyzed concentration range was 50–300 μg/mL. On the basis of the experiments carried out, the following conclusions have been made. Extracts of the leaves and rhizomes of Sansevieria cylindrica and Sansevieria trifasciata do not possess antitumor activity. Extracts of the leaves of Polianthes tuberosa and Furcraea gigantea, which were cytotoxic at high concentrations, cause cell death at 50 μg/mL in the amount of 21.35 ± 1.86 and 15.6 ± 3.23, respectively. Extracts of Polianthes tuberosa bulbs and Yucca filamentosa leaves are able to induce apoptosis at higher concentrations. When the concentration reaches 100 μg/mL, the proportion of apoptotic cells for these plants is 45.76 ± 1.34 and 11.33 ± 0.07, respectively. The number of dead cells at the concentration of 300 μg/mL increased up to 73.33 ± 3.05 and 81.75 ± 4.07. The results have great importance for development of new drugs based on metabolites from these plant extracts.

  14. Behaviour of human endothelial cells on surface modified NiTi alloy.

    Science.gov (United States)

    Plant, Stuart D; Grant, David M; Leach, Lopa

    2005-09-01

    Intravascular stents are being designed which utilise the shape memory properties of NiTi alloy. Despite the clinical advantages afforded by these stents their application has been limited by concerns about the large nickel ion content of the alloy. In this study, the surface chemistry of NiTi alloy was modified by mechanical polishing and oxidising heat treatments and subsequently characterised using X-ray photon spectroscopy (XPS). The effect of these surfaces on monolayer formation and barrier integrity of human umbilical vein endothelial cells (HUVEC) was then assessed by confocal imaging of the adherens junctional molecule VE-cadherin, perijunctional actin and permeability to 42kDa dextrans. Dichlorofluoroscein assays were used to measure oxidative stress in the cells. XPS analysis of NiTi revealed its surface to be dominated by TiO(2). However, where oxidation had occurred after mechanical polishing or post polishing heat treatments at 300 and 400 degrees C in air, a significant amount of metallic nickel or nickel oxide species (10.5 and 18.5 at%) remained on the surface. Exposure of HUVECs to these surfaces resulted in increased oxidative stress within the cells, loss of VE-cadherin and F-actin and significantly increased paracellular permeability. These pathological phenomena were not found in cells grown on NiTi which had undergone heat treatment at 600 degrees C. At this temperature thickening of the TiO(2) layer had occurred due to diffusion of titanium ions from the bulk of the alloy, displacing nickel ions to sub-surface areas. This resulted in a significant reduction in nickel ions detectable on the sample surface (4.8 at%). This study proposes that the integrity of human endothelial monolayers on NiTi is dependent upon the surface chemistry of the alloy and that this can be manipulated, using simple oxidising heat treatments.

  15. Block copolymer directed synthesis of mesoporous TiO 2 for dye-sensitized solar cells

    KAUST Repository

    Nedelcu, Mihaela

    2009-01-01

    The morphology of TiO2 plays an important role in the operation of solid-state dye-sensitized solar cells. By using polyisoprene-block- ethyleneoxide (PI-b-PEO) copolymers as structure directing agents for a sol-gel based synthesis of mesoporous TiO2, we demonstrate a strategy for the detailed control of the semiconductor morphology on the 10 nm length scale. The careful adjustment of polymer molecular weight and titania precursor content is used to systematically vary the material structure and its influence upon solar cell performance is investigated. Furthermore, the use of a partially sp 2 hybridized structure directing polymer enables the crystallization of porous TiO2 networks at high temperatures without pore collapse, improving its performance in solid-state dye-sensitized solar cells. © 2009 The Royal Society of Chemistry.

  16. Regulation of cytokine production in human alveolar macrophages and airway epithelial cells in response to ambient air pollution particles: Further mechanistic studies

    International Nuclear Information System (INIS)

    Becker, Susanne; Mundandhara, Sailaja; Devlin, Robert B.; Madden, Michael

    2005-01-01

    In order to better understand how ambient air particulate matter (PM) affect lung health, the two main airway cell types likely to interact with inhaled particles, alveolar macrophages (AM) and airway epithelial cells have been exposed to particles in vitro and followed for endpoints of inflammation, and oxidant stress. Separation of Chapel Hill PM 10 into fine and coarse size particles revealed that the main proinflammatory response (TNF, IL-6, COX-2) in AM was driven by material present in the coarse PM, containing 90-95% of the stimulatory material in PM10. The particles did not affect expression of hemoxygenase-1 (HO-1), a sensitive marker of oxidant stress. Primary cultures of normal human bronchial epithelial cells (NHBE) also responded to the coarse fraction with higher levels of IL-8 and COX-2, than induced by fine or ultrafine PM. All size PM induced oxidant stress in NHBE, while fine PM induced the highest levels of HO-1 expression. The production of cytokines in AM by both coarse and fine particles was blocked by the toll like receptor 4 (TLR4) antagonist E5531 involved in the recognition of LPS and Gram negative bacteria. The NHBE were found to recognize coarse and fine PM through TLR2, a receptor with preference for recognition of Gram positive bacteria. Compared to ambient PM, diesel PM induced only a minimal cytokine response in both AM and NHBE. Instead, diesel suppressed LPS-induced TNF and IL-8 release in AM. Both coarse and fine ambient air PM were also found to inhibit LPS-induced TNF release while silica, volcanic ash or carbon black had no inhibitory effect. Diesel particles did not affect cytokine mRNA induction nor protein accumulation but interfered with the release of cytokine from the cells. Ambient coarse and fine PM, on the other hand, inhibited both mRNA induction and protein production. Exposure to coarse and fine PM decreased the expression of TLR4 in the macrophages. Particle-induced decrease in TLR4 and hyporesponsiveness to LPS

  17. Cell adhesion on NiTi thin film sputter-deposited meshes

    International Nuclear Information System (INIS)

    Loger, K.; Engel, A.; Haupt, J.; Li, Q.; Lima de Miranda, R.; Quandt, E.; Lutter, G.; Selhuber-Unkel, C.

    2016-01-01

    Scaffolds for tissue engineering enable the possibility to fabricate and form biomedical implants in vitro, which fulfill special functionality in vivo. In this study, free-standing Nickel–Titanium (NiTi) thin film meshes were produced by means of magnetron sputter deposition. Meshes contained precisely defined rhombic holes in the size of 440 to 1309 μm 2 and a strut width ranging from 5.3 to 9.2 μm. The effective mechanical properties of the microstructured superelastic NiTi thin film were examined by tensile testing. These results will be adapted for the design of the holes in the film. The influence of hole and strut dimensions on the adhesion of sheep autologous cells (CD133 +) was studied after 24 h and after seven days of incubation. Optical analysis using fluorescence microscopy and scanning electron microscopy showed that cell adhesion depends on the structural parameters of the mesh. After 7 days in cell culture a large part of the mesh was covered with aligned fibrous material. Cell adhesion is particularly facilitated on meshes with small rhombic holes of 440 μm 2 and a strut width of 5.3 μm. Our results demonstrate that free-standing NiTi thin film meshes have a promising potential for applications in cardiovascular tissue engineering, particularly for the fabrication of heart valves. - Highlights: • Freestanding NiTi thin film scaffolds were fabricated with magnetron sputtering process. • Effective mechanical properties of NiTi scaffolds can be adapted by the mesh structure parameters. • Cell adhesion on the NiTi thin film scaffold is controlled by the structure parameters of the mesh. • Cells strongly adhere after seven days and form a confluent layer on the mesh.

  18. Cell adhesion on NiTi thin film sputter-deposited meshes

    Energy Technology Data Exchange (ETDEWEB)

    Loger, K. [Inorganic Functional Materials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany); Engel, A.; Haupt, J. [Department of Cardiovascular Surgery, University Hospital of Schleswig-Holstein, Kiel (Germany); Li, Q. [Biocompatible Nanomaterials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany); Lima de Miranda, R. [Inorganic Functional Materials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany); ACQUANDAS GmbH, Kiel (Germany); Quandt, E. [Inorganic Functional Materials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany); Lutter, G. [Department of Cardiovascular Surgery, University Hospital of Schleswig-Holstein, Kiel (Germany); Selhuber-Unkel, C. [Biocompatible Nanomaterials, Institute for Materials Science, Faculty of Engineering, University of Kiel (Germany)

    2016-02-01

    Scaffolds for tissue engineering enable the possibility to fabricate and form biomedical implants in vitro, which fulfill special functionality in vivo. In this study, free-standing Nickel–Titanium (NiTi) thin film meshes were produced by means of magnetron sputter deposition. Meshes contained precisely defined rhombic holes in the size of 440 to 1309 μm{sup 2} and a strut width ranging from 5.3 to 9.2 μm. The effective mechanical properties of the microstructured superelastic NiTi thin film were examined by tensile testing. These results will be adapted for the design of the holes in the film. The influence of hole and strut dimensions on the adhesion of sheep autologous cells (CD133 +) was studied after 24 h and after seven days of incubation. Optical analysis using fluorescence microscopy and scanning electron microscopy showed that cell adhesion depends on the structural parameters of the mesh. After 7 days in cell culture a large part of the mesh was covered with aligned fibrous material. Cell adhesion is particularly facilitated on meshes with small rhombic holes of 440 μm{sup 2} and a strut width of 5.3 μm. Our results demonstrate that free-standing NiTi thin film meshes have a promising potential for applications in cardiovascular tissue engineering, particularly for the fabrication of heart valves. - Highlights: • Freestanding NiTi thin film scaffolds were fabricated with magnetron sputtering process. • Effective mechanical properties of NiTi scaffolds can be adapted by the mesh structure parameters. • Cell adhesion on the NiTi thin film scaffold is controlled by the structure parameters of the mesh. • Cells strongly adhere after seven days and form a confluent layer on the mesh.

  19. Formulation of vitamin D encapsulated cinnamon oil nanoemulsion: Its potential anti-cancerous activity in human alveolar carcinoma cells.

    Science.gov (United States)

    Meghani, Nikita; Patel, Pal; Kansara, Krupa; Ranjan, Shivendu; Dasgupta, Nandita; Ramalingam, Chidambaram; Kumar, Ashutosh

    2018-06-01

    Cinnamon oil is used for medicinal purpose since ancient time because of its antioxidant activity. Oil-in-water nanoemulsion (NE) of cinnamon oil was formulated using cinnamon oil, nonionic surfactant Tween 80 and water by ultrasonication technique. Phase diagram was constructed to investigate the influence of oil, water and surfactant concentration. Vitamin D encapsulated cinnamon oil NE was fabricated by wash out method followed by ultrasonication in similar fashion. The hydrodynamic size of cinnamon oil NE and vitamin D encapsulated cinnamon oil NE was observed as 40.52 and 48.96 nm in complete DMEM F12 media respectively. We focused on the cytotoxic and genotoxic responses of NEs in A549 cells in concentration dependent manner. We observed that both NEs induce DNA damage along with corresponding increase in micronucleus frequency that is evident from the comet and CBMN assay. Both the NEs arrested the cell cycle progression in G0/G1 phase, showed increased expression of Bax, capase-3 and caspase-9 and decrease expression of BcL2 proteins along with significant (p oil as carrier for lipophilic nutraceutical like vitamin D. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Research Update: Doping ZnO and TiO2 for solar cells

    Directory of Open Access Journals (Sweden)

    Robert L. Z. Hoye

    2013-12-01

    Full Text Available ZnO and TiO2 are two of the most commonly used n-type metal oxide semiconductors in new generation solar cells due to their abundance, low-cost, and stability. ZnO and TiO2 can be used as active layers, photoanodes, buffer layers, transparent conducting oxides, hole-blocking layers, and intermediate layers. Doping is essential to tailor the materials properties for each application. The dopants used and their impact in solar cells are reviewed. In addition, the advantages, disadvantages, and commercial potential of the various fabrication methods of these oxides are presented.

  1. Alveolar ridge augmentation by osteoinductive materials in goats

    DEFF Research Database (Denmark)

    Pinholt, E M; Haanaes, H R; Roervik, M

    1992-01-01

    The purpose of the present study was to determine whether alveolar ridge augmentation could be induced in goats. In 12 male goats allogenic, demineralized, and lyophilized dentin or bone was implanted subperiosteally on the buccal sides of the natural edentulous regions of the alveolar process...... of the mandible. Light microscopic evaluation revealed fibrous encapsulation, a few multinuclear giant cells, little inflammatory reaction, and no osteoinduction. It was concluded that no osteoinduction took place in goats....

  2. HOS cell adhesion on Ti6Al4V surfaces texturized by laser engraving

    Science.gov (United States)

    Sandoval Amador, A.; Carreño Garcia, H.; Escobar Rivero, P.; Peña Ballesteros, D. Y.; Estupiñán Duran, H. A.

    2016-02-01

    The cell adhesion of the implant is determinate by the chemical composition, topography, wettability, surface energy and biocompatibility of the biomaterial. In this work the interaction between human osteosarcoma HOS cells and textured Ti6Al4V surfaces were evaluated. Ti6Al4V surfaces were textured using a CO2 laser in order to obtain circular spots on the surfaces. Test surfaces were uncoated (C1) used as a control surface, and surfaces with points obtained by laser engraving, with 1mm spacing (C2) and 0.5mm (C3). The HOS cells were cultured in RPMI-1640 medium with 10% fetal bovine serum and 1% antibiotics. No cells toxicity after one month incubation time occurred. The increased cell adhesion and cell spreading was observed after 1, 3 and 5 days without significant differences between the sample surfaces (C2 and C3) and control (uncoated) at the end of the experiment.

  3. HOS cell adhesion on Ti6Al4V surfaces texturized by laser engraving

    International Nuclear Information System (INIS)

    Sandoval Amador, A; Carreño Garcia, H; Escobar Rivero, P; Peña Ballesteros, D Y; Estupiñán Duran, H A

    2016-01-01

    The cell adhesion of the implant is determinate by the chemical composition, topography, wettability, surface energy and biocompatibility of the biomaterial. In this work the interaction between human osteosarcoma HOS cells and textured Ti 6 Al 4 V surfaces were evaluated. Ti 6 Al 4 V surfaces were textured using a CO 2 laser in order to obtain circular spots on the surfaces. Test surfaces were uncoated (C1) used as a control surface, and surfaces with points obtained by laser engraving, with 1mm spacing (C2) and 0.5mm (C3). The HOS cells were cultured in RPMI-1640 medium with 10% fetal bovine serum and 1% antibiotics. No cells toxicity after one month incubation time occurred. The increased cell adhesion and cell spreading was observed after 1, 3 and 5 days without significant differences between the sample surfaces (C2 and C3) and control (uncoated) at the end of the experiment. (paper)

  4. Toxic Effects of the Major Components of Diesel Exhaust in Human Alveolar Basal Epithelial Cells (A549

    Directory of Open Access Journals (Sweden)

    Pavel Rossner

    2016-08-01

    Full Text Available We investigated the toxicity of benzo[a]pyrene (B[a]P, 1-nitropyrene (1-NP and 3-nitrobenzanthrone (3-NBA in A549 cells. Cells were treated for 4 h and 24 h with: B[a]P (0.1 and 1 μM, 1-NP (1 and 10 μM and 3-NBA (0.5 and 5 μM. Bulky DNA adducts, lipid peroxidation, DNA and protein oxidation and mRNA expression of CYP1A1, CYP1B1, NQO1, POR, AKR1C2 and COX2 were analyzed. Bulky DNA adducts were induced after both treatment periods; the effect of 1-NP was weak. 3-NBA induced high levels of bulky DNA adducts even after 4-h treatment, suggesting rapid metabolic activation. Oxidative DNA damage was not affected. 1-NP caused protein oxidation and weak induction of lipid peroxidation after 4-h incubation. 3-NBA induced lipid peroxidation after 24-h treatment. Unlike B[a]P, induction of the aryl hydrocarbon receptor, measured as mRNA expression levels of CYP1A1 and CYP1B1, was low after treatment with polycyclic aromatic hydrocarbon (PAH nitro-derivatives. All test compounds induced mRNA expression of NQO1, POR, and AKR1C2 after 24-h treatment. AKR1C2 expression indicates involvement of processes associated with reactive oxygen species generation. This was supported further by COX2 expression induced by 24-h treatment with 1-NP. In summary, 3-NBA was the most potent genotoxicant, whereas 1-NP exhibited the strongest oxidative properties.

  5. MicroRNA regulatory networks reflective of polyhexamethylene guanidine phosphate-induced fibrosis in A549 human alveolar adenocarcinoma cells.

    Science.gov (United States)

    Shin, Da Young; Jeong, Mi Ho; Bang, In Jae; Kim, Ha Ryong; Chung, Kyu Hyuck

    2018-05-01

    Polyhexamethylene guanidine phosphate (PHMG-phosphate), an active component of humidifier disinfectant, is suspected to be a major cause of pulmonary fibrosis. Fibrosis, induced by recurrent epithelial damage, is significantly affected by epigenetic regulation, including microRNAs (miRNAs). The aim of this study was to investigate the fibrogenic mechanisms of PHMG-phosphate through the profiling of miRNAs and their target genes. A549 cells were treated with 0.75 μg/mL PHMG-phosphate for 24 and 48 h and miRNA microarray expression analysis was conducted. The putative mRNA targets of the miRNAs were identified and subjected to Gene Ontology analysis. After exposure to PHMG-phosphate for 24 and 48 h, 46 and 33 miRNAs, respectively, showed a significant change in expression over 1.5-fold compared with the control. The integrated analysis of miRNA and mRNA microarray results revealed the putative targets that were prominently enriched were associated with the epithelial-mesenchymal transition (EMT), cell cycle changes, and apoptosis. The dose-dependent induction of EMT by PHMG-phosphate exposure was confirmed by western blot. We identified 13 putative EMT-related targets that may play a role in PHMG-phosphate-induced fibrosis according to the Comparative Toxicogenomic Database. Our findings contribute to the comprehension of the fibrogenic mechanism of PHMG-phosphate and will aid further study on PHMG-phosphate-induced toxicity. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Crystal structure mediates mode of cell death in TiO2 nanotoxicity

    International Nuclear Information System (INIS)

    Braydich-Stolle, Laura K.; Schaeublin, Nicole M.; Murdock, Richard C.; Jiang, Jingkun; Biswas, Pratim; Schlager, John J.; Hussain, Saber M.

    2009-01-01

    Certain properties that nanoparticles possess differentiate them from their bulk counterparts, and these characteristics must be evaluated prior to nanoparticle studies and include: size, shape, dispersion, physical and chemical properties, surface area, and surface chemistry. Early nanotoxicity studies evaluating TiO 2 have yielded conflicting data which identify either size or crystal structure as the mediating property for nano-TiO 2 toxicity. However, it is important to note that none of these studies examined size with the crystal structure composition controlled for or examined crystal structure while controlling the nanoparticle size. The goal of this study was to evaluate the role of size and crystal structure in TiO 2 nanotoxicity while controlling for as many other nanoproperties as possible using the HEL-30 mouse keratinocyte cell line as a model for dermal exposure. In the size-dependent studies, all the nanoparticles are 100% anatase, and aggregate sizes were determined in order to take into account the effect of agglomeration on size-dependent toxicity. In addition, varying crystal structures were assessed while the size of the nanoparticles was controlled. We were able to identify that both size and crystal structure contribute to cytotoxicity and that the mechanism of cell death varies based on crystal structure. The 100% anatase TiO 2 nanoparticles, regardless of size, induced cell necrosis, while the rutile TiO 2 nanoparticles initiated apoptosis through formation of reactive oxygen species (ROS).

  7. Crystal structure mediates mode of cell death in TiO{sub 2} nanotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Braydich-Stolle, Laura K.; Schaeublin, Nicole M.; Murdock, Richard C. [Wright-Patterson AFB, Applied Biotechnology Branch, Human Effectiveness Directorate, Air Force Research Laboratory (United States); Jiang, Jingkun; Biswas, Pratim [Washington University in St. Louis, Department of Energy, Environmental, and Chemical Engineering (United States); Schlager, John J.; Hussain, Saber M., E-mail: Saber.Hussain@wpafb.af.mi [Wright-Patterson AFB, Applied Biotechnology Branch, Human Effectiveness Directorate, Air Force Research Laboratory (United States)

    2009-08-15

    Certain properties that nanoparticles possess differentiate them from their bulk counterparts, and these characteristics must be evaluated prior to nanoparticle studies and include: size, shape, dispersion, physical and chemical properties, surface area, and surface chemistry. Early nanotoxicity studies evaluating TiO{sub 2} have yielded conflicting data which identify either size or crystal structure as the mediating property for nano-TiO{sub 2} toxicity. However, it is important to note that none of these studies examined size with the crystal structure composition controlled for or examined crystal structure while controlling the nanoparticle size. The goal of this study was to evaluate the role of size and crystal structure in TiO{sub 2} nanotoxicity while controlling for as many other nanoproperties as possible using the HEL-30 mouse keratinocyte cell line as a model for dermal exposure. In the size-dependent studies, all the nanoparticles are 100% anatase, and aggregate sizes were determined in order to take into account the effect of agglomeration on size-dependent toxicity. In addition, varying crystal structures were assessed while the size of the nanoparticles was controlled. We were able to identify that both size and crystal structure contribute to cytotoxicity and that the mechanism of cell death varies based on crystal structure. The 100% anatase TiO{sub 2} nanoparticles, regardless of size, induced cell necrosis, while the rutile TiO{sub 2} nanoparticles initiated apoptosis through formation of reactive oxygen species (ROS).

  8. Effect of TiO{sub 2} nanoporous size on cell viability

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Elisa Marchezini; Weitzel, Ana Paula dos Reis; Rosario, Camila Jaques; Duarte, Larissa Mara Batista; Martins, Maximiliano Delany, E-mail: elisamarch@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2016-07-01

    Full text: Titanium play an important role in the manufacturing of dental implants. The oxide layer naturally formed on the surface of a titanium device provides biocompatible characteristics, which significantly supports the osseointegration process. It has been supported that a nanostructured TiO{sub 2} surface affects positively the adhesion and proliferation of osteoblasts [1]. A widely technique used for obtaining nanoporous titania is anodizing (or anodic oxidation), which is a non-spontaneous reaction induced by a source of electric current, typically using a solution containing HF [1]. TiO{sub 2} pore diameter can be well controlled in a broad range by adjusting the potentiostatic voltage. J. Park et al. have investigated the development of mesenchymal stem cells on a TiO{sub 2} nanoporous surface and reported a direct relation between the cellular responses with the pore diameter, in the range of 15 - 100 nm [2]. The objective of this work was to investigate deeply the influence of TiO{sub 2} pore diameter in cell viability. Titanium surfaces were anodized by using an electrochemical cell under constant agitation, controlled temperature, and different applied voltages in order to produce different pore diameter, in the nanosize range 15-100 nm. Then, cell proliferation, differentiation, adhesion and viability were investigated in vitro [3]. Surface morphology and chemical composition of the surface treated Ti samples were investigated by SEM, EDS and XPS. The results confirmed the production of a uniform layer of nanoporous TiO{sub 2} with different average porous diameter. The details of sample preparation and the results of cell response tests are going to be presented. [1] S. Minagar et al., Acta Biomat. 8 (2012) 2875; M. Kulkarni et al., Nanotechnology 26 (2015) 062002. [2] J. Park et al., Nano Letters 7 (2007) 1686. [3] G. G. Genchi et al., RSC Adv. 6 (2016) 18502. (author)

  9. TiO2 micro-flowers composed of nanotubes and their application to dye-sensitized solar cells

    Science.gov (United States)

    Kim, Woong-Rae; Park, Hun; Choi, Won-Youl

    2014-02-01

    TiO2 micro-flowers were made to bloom on Ti foil by the anodic oxidation of Ti-protruding dots with a cylindrical shape. Arrays of the Ti-protruding dots were prepared by photolithography, which consisted of coating the photoresists, attaching a patterned mask, illuminating with UV light, etching the Ti surface by reactive ion etching (RIE), and stripping the photoresist on the Ti foil. The procedure for the blooming of the TiO2 micro-flowers was analyzed by field emission scanning electron microscopy (FESEM) as the anodizing time was increased. Photoelectrodes of dye-sensitized solar cells (DSCs) were fabricated using TiO2 micro-flowers. Bare TiO2 nanotube arrays were used for reference samples. The short-circuit current ( J sc) and the power conversion efficiency of the DSCs based on the TiO2 micro-flowers were 4.340 mA/cm2 and 1.517%, respectively. These values of DSCs based on TiO2 micro-flowers were higher than those of bare samples. The TiO2 micro-flowers had a larger surface area for dye adsorption compared to bare TiO2 nanotube arrays, resulting in improved J sc characteristics. The structure of the TiO2 micro-flowers allowed it to adsorb dyes very effectively, also demonstrating the potential to achieve higher power conversion efficiency levels for DSCs compared to a bare TiO2 nanotube array structure and the conventional TiO2 nanoparticle structure.

  10. Sb2S3 surface modification induced remarkable enhancement of TiO2 core/shell nanowries solar cells

    International Nuclear Information System (INIS)

    Meng, Xiuqing; Wang, Xiaozhou; Zhong, Mianzeng; Wu, Fengmin; Fang, Yunzhang

    2013-01-01

    This study presents the fabrication of a novel dye-sensitized solar cell with Sb 2 S 3 -modified TiO 2 nanowire (NW) arrays/TiO 2 nanoparticles (NP) (TiO 2(NWs) /TiO 2(NPs) /Sb 2 S 3 ) as the anodes and N719 dye as the sensitizer. A solar conversion efficiency of 4.91% at 1 sun illumination was achieved for the composite cell, which is markedly higher than the efficiency rates obtained using TiO 2 and TiO 2(NWs) /Sb 2 S 3 /TiO 2(NPs) NW cells, calculated at 2.36% and 3.11%, respectively. The improved efficiency results from the large surface area of the NPs, as well as the expansion of the light absorption region and high absorption coefficient by Sb 2 S 3 surface modification. - Graphical abstract: A novel TiO 2(NWs) /TiO 2(NPs) /Sb 2 S 3 dye sensitized solar cells (DSSCs) is fabricated, a solar conversion efficiency of 4.91 % at 1 sun illumination is achieved. Highlights: ► We fabricate sandwich structured TiO 2 dye-sensitized solar cells. ► The anode of the solar cells consist of Sb 2 S 3 modified TiO 2 nanowire arrays/TiO 2 nanopartices. ► A solar conversion efficiency of 4.91% at 1 sun illumination is achieved. ► The high efficiency results from large surface area and expanded light adsorption of the anode

  11. Interconnected TiO2 Nanowire Networks for PbS Quantum Dot Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Fan Xu

    2012-01-01

    Full Text Available We present a simple method for the fabrication of an interconnected porous TiO2 nanostructured film via dip coating in a colloidal suspension of ultrathin TiO2 nanowires followed by high-temperature annealing. The spheroidization of the nanowires and the fusing of the loosely packed nanowire films at the contact points lead to the formation of nanopores. Using this interconnected TiO2 nanowire network for electron transport, a PbS/TiO2 heterojunction solar cell with a large short-circuit current of 2.5 mA/cm2, a Voc of 0.6 V, and a power conversion efficiency of 5.4% is achieved under 8.5 mW/cm2 white light illumination. Compared to conventional planar TiO2 film structures, these results suggest superior electron transport properties while still providing the large interfacial area between PbS quantum dots and TiO2 required for efficient exciton dissociation.

  12. Electrochemical Characterization of TiO 2 Blocking Layers for Dye-Sensitized Solar Cells

    KAUST Repository

    Kavan, Ladislav

    2014-07-31

    Thin compact layers of TiO2 are grown by thermal oxidation of Ti, by spray pyrolysis, by electrochemical deposition, and by atomic layer deposition. These layers are used in dye-sensitized solar cells to prevent recombination of electrons from the substrate (FTO or Ti) with the hole-conducting medium at this interface. The quality of blocking is evaluated electrochemically by methylviologen, ferro/ferricyanide, and spiro-OMeTAD as the model redox probes. Two types of pinholes in the blocking layers are classified, and their effective area is quantified. Frequency-independent Mott-Schottky plots are fitted from electrochemical impedance spectroscopy. Certain films of the thicknesses of several nanometers allow distinguishing the depletion layer formation both in the TiO2 film and in the FTO substrate underneath the titania film. The excellent blocking function of thermally oxidized Ti, electrodeposited film (60 nm), and atomic-layer-deposited films (>6 nm) is documented by the relative pinhole area of less than 1%. However, the blocking behavior of electrodeposited and atomic-layer-deposited films is strongly reduced upon calcination at 500 °C. The blocking function of spray-pyrolyzed films is less good but also less sensitive to calcination. The thermally oxidized Ti is well blocking and insensitive to calcination. © 2014 American Chemical Society.

  13. Yttrium-substituted nanocrystalline TiO 2 photoanodes for perovskite based heterojunction solar cells

    KAUST Repository

    Qin, Peng; Domanski, Anna L.; Chandiran, Aravind Kumar; Berger, Rü diger; Butt, Hans-Jü rgen; Dar, M. Ibrahim; Moehl, Thomas; Tetreault, Nicolas; Gao, Peng; Ahmad, Shahzada; Nazeeruddin, Mohammad K.; Grä tzel, Michael

    2014-01-01

    We report the use of Y3+-substituted TiO2 (0.5%Y-TiO2) in solid-state mesoscopic solar cells, consisting of CH3NH3PbI3 as the light harvester and spiro-OMeTAD as the hole transport material. A power conversion efficiency of 11.2% under simulated AM 1.5 full sun illumination was measured. A 15% improvement in the short-circuit current density was obtained compared with pure TiO2, due to the effect of Y3+ on the dimensions of perovskite nanoparticles formed on the semiconductor surface, showing that the surface modification of the semiconductor is an effective way to improve the light harvesters' morphology and electron transfer properties in the solid-state mesoscopic solar cells. © 2013 The Royal Society of Chemistry.

  14. Yttrium-substituted nanocrystalline TiO 2 photoanodes for perovskite based heterojunction solar cells

    KAUST Repository

    Qin, Peng

    2014-01-01

    We report the use of Y3+-substituted TiO2 (0.5%Y-TiO2) in solid-state mesoscopic solar cells, consisting of CH3NH3PbI3 as the light harvester and spiro-OMeTAD as the hole transport material. A power conversion efficiency of 11.2% under simulated AM 1.5 full sun illumination was measured. A 15% improvement in the short-circuit current density was obtained compared with pure TiO2, due to the effect of Y3+ on the dimensions of perovskite nanoparticles formed on the semiconductor surface, showing that the surface modification of the semiconductor is an effective way to improve the light harvesters\\' morphology and electron transfer properties in the solid-state mesoscopic solar cells. © 2013 The Royal Society of Chemistry.

  15. Enhanced photovoltaic properties of perovskite solar cells by TiO2 homogeneous hybrid structure.

    Science.gov (United States)

    Su, Pengyu; Fu, Wuyou; Yao, Huizhen; Liu, Li; Ding, Dong; Feng, Fei; Feng, Shuang; Xue, Yebin; Liu, Xizhe; Yang, Haibin

    2017-10-01

    In this paper, we fabricated a TiO 2 homogeneous hybrid structure for application in perovskite solar cells (PSCs) under ambient conditions. Under the standard air mass 1.5 global (AM 1.5G) illumination, PSCs based on homogeneous hybrid structure present a maximum power conversion efficiency of 5.39% which is higher than that of pure TiO 2 nanosheets. The enhanced properties can be explained by the better contact of TiO 2 nanosheets/nanoparticles with CH 3 NH 3 PbI 3 and fewer pinholes in electron transport materials. The advent of such unique structure opens up new avenues for the future development of high-efficiency photovoltaic cells.

  16. Inflammatory effects induced by selected limonene oxidation products: 4-OPA, IPOH, 4-AMCH in human bronchial (16HBE14o-) and alveolar (A549) epithelial cell lines.

    Science.gov (United States)

    Lipsa, Dorelia; Leva, Paolo; Barrero-Moreno, Josefa; Coelhan, Mehmet

    2016-11-16

    Limonene, a monoterpene abundantly present in most of the consumer products (due to its pleasant citrus smell), easily undergoes ozonolysis leading to several limonene oxidation products (LOPs) such as 4-acetyl-1-methylcyclohexene (4-AMCH), 4-oxopentanal (4-OPA) and 3-isopropenyl-6-oxoheptanal (IPOH). Toxicological studies have indicated that human exposure to limonene and ozone can cause adverse airway effects. However, little attention has been paid to the potential health impact of specific LOPs, in particular of IPOH, 4-OPA and 4-AMCH. This study evaluates the cytotoxic effects of the selected LOPs on human bronchial epithelial (16HBE14o-) and alveolar epithelial (A549) cell lines by generating concentration-response curves using the neutral red uptake assay and analyzing the inflammatory response with a series of cytokines/chemokines. The cellular viability was mostly reduced by 4-OPA [IC 50 =1.6mM (A549) and 1.45mM (16HBE14o-)] when compared to IPOH [IC 50 =3.5mM (A549) and 3.4mM (16HBE14o-)] and 4-AMCH [IC 50 could not be calculated]. As a result from the inflammatory response, IPOH [50μM] induced an increase of both IL-6 and IL-8 secretion in A549 (1.5-fold change) and in 16HBE14o- (2.8- and 7-fold change respectively). 4-OPA [50μM] treatment of A549 increased IL-6 (1.4-times) and IL-8 (1.3-times) levels, while in 16HBE14o- had an opposite effect. A549 treated with 4-AMCH [50μM] elevate both IL-6 and IL-8 levels by 1.2-times, while in 16HBE14o- had an opposite effect. Based on our results, lung cellular injury characterized by inflammatory cytokine release was observed for both cell lines treated with the selected chemicals at concentrations that did not affect their cellular viability. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  17. Electrophoretic deposition of nanocrystalline TiO2 films on Ti substrates for use in flexible dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Tan Weiwei; Yin Xiong; Zhou Xiaowen; Zhang Jingbo; Xiao Xurui; Lin Yuan

    2009-01-01

    Nanocrystalline TiO 2 films were prepared on flexible Ti-metal sheets by electrophoretic deposition followed by chemical treatment with tetra-n-butyl titanate (TBT) and sintering at 450 deg. C. X-ray diffraction (XRD) analysis indicates that TBT treatment led to the formation of additional anatase TiO 2 , which plays an important role in improving the interconnection between TiO 2 particles, as well as the adherence of the film to the substrate, and in modifying the surface properties of the nanocrystalline particles. The effect of TBT treatment on the electron transport in the nanocrystalline films was studied by intensity-modulated photocurrent spectroscopy (IMPS). An increase in the conversion efficiency was obtained for the dye-sensitized solar cells with TBT-treated nanocrystalline TiO 2 films. The cell performance was further optimized by designing nanocrystalline TiO 2 films with a double-layer structure composed of a light-scattering layer and a transparent layer. The light-scattering effect of the double-layer nanocrystalline films was evaluated by diffuse reflectance spectra. Employing the double-layer nanocrystalline films as the photoelectrodes resulted in a significant improvement in the incident photo-to-current conversion efficiency of the corresponding cells due to enhanced solar absorption by light scattering. A high conversion efficiency of 6.33% was measured under illumination with 100 mW cm -2 (AM 1.5) simulated sunlight.

  18. Adjustment of Conduction Band Edge of Compact TiO2 Layer in Perovskite Solar Cells Through TiCl4 Treatment.

    Science.gov (United States)

    Murakami, Takurou N; Miyadera, Tetsuhiko; Funaki, Takashi; Cojocaru, Ludmila; Kazaoui, Said; Chikamatsu, Masayuki; Segawa, Hiroshi

    2017-10-25

    Perovskite solar cells (PSCs) without a mesoporous TiO 2 layer, that is, planar-type PSCs exhibit poorer cell performance as compared to PSCs with a porous TiO 2 layer, owing to inefficient electron transfer from the perovskite layer to the compact TiO 2 layer in the former case. The matching of the conduction band levels of perovskite and the compact TiO 2 layer is thus essential for enhancing PSC performance. In this study, we demonstrate the shifting of the conduction band edge (CBE) of the compact TiO 2 layer through a TiCl 4 treatment, with the aim of improving PSC performance. The CBE of the compact TiO 2 layer was shifted to a higher level through the TiCl 4 treatment and then shifted in the opposite direction, that is, to a lower level, through a subsequent heat treatment. These shifts in the CBE were reflected in the PSC performance. The TiCl 4 -treated PSC showed an increase in the open-circuit voltage of more than 150 mV, as well as a decrease of 100 mV after being heated at 450 °C. On the other hand, the short-circuit current decreased after the treatment but increased after heating at temperatures higher than 300 °C. The treated PSC subjected to subsequent heating at 300 °C exhibited the best performance, with the power conversion efficiency of the PSC being 17% under optimized conditions.

  19. Effect of TiOx compact layer with varied components on the performance of dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yanling; Ai, Xianglong; Wang, Xiaomeng; Wang, Qi; Huang, Jianguo; Wu, Tao, E-mail: tao_wu@zju.edu.cn

    2014-05-01

    Graphical abstract: - Highlights: • TiOx compact layers with varied components are deposited by sputtering deposition. • TiOx compact layers suppressed the recombination at the FTO glass/ electrolyte interface effectively. • 20 nm-TiOx compact layer with the lowest x value (named T1) gave the highest charge transfer or transport and reduced recombination most. • Lower value of x in TiOx showed slightly better transmittance. • Lower value of x in TiOx reveals higher conductivity and better charge transfer from the porous TiO{sub 2} to the substrate. - Abstract: In this study, approximately 20 nm thick compact layers of TiOx with varied components are deposited by physical vapor deposition. The performance of these layers in solar cells is investigated. The TiOx compact layers consist of T1 (with Ti{sup 0}, Ti{sup 2+}, Ti{sup 3+}, and Ti{sup 4+}), T2 (with Ti{sup 3+} and Ti{sup 4+}), and T3 (with Ti{sup 4+}). Results show that the optimum compact layer is T1, which exhibits an approximately 61% enhancement in energy conversion efficiency compared with the bare cell. Mott–Schottky plots indicate that the carrier concentration decreases and the flatband becomes less negative with decreasing x, which consequently increases the likelihood of charge transfer from the nanoporous TiO{sub 2} to the TiOx compact layers. Furthermore, a decrease in the x value of TiOx results in lower resistance. Voltage decay and electrical impedance spectrum (EIS) show that the electron-carrier lifetime and charge recombination reduction are improved the most by T1. Consequently, TiOx with smaller x works better as a compact layer. However, a solar cell with T2 shows weak enhancement of photovoltaic performance. Cyclic voltammetry and EIS illustrate that the low recombination blocking and high resistance of T2 may be a result of its large pore size and weak adhesion to fluorine-doped tin oxide glass.

  20. Femtosecond laser-induced microstructures on Ti substrates for reduced cell adhesion

    Science.gov (United States)

    Heitz, J.; Plamadeala, C.; Muck, M.; Armbruster, O.; Baumgartner, W.; Weth, A.; Steinwender, C.; Blessberger, H.; Kellermair, J.; Kirner, S. V.; Krüger, J.; Bonse, J.; Guntner, A. S.; Hassel, A. W.

    2017-12-01

    Miniaturized pacemakers with a surface consisting of a Ti alloy may have to be removed after several years from their implantation site in the heart and shall, therefore, not be completely overgrown by cells or tissue. A method to avoid this may be to create at the surface by laser-ablation self-organized sharp conical spikes, which provide too little surface for cells (i.e., fibroblasts) to grow on. For this purpose, Ti-alloy substrates were irradiated in the air by 790 nm Ti:sapphire femtosecond laser pulses at fluences above the ablation threshold. The laser irradiation resulted in pronounced microstructure formation with hierarchical surface morphologies. Murine fibroblasts were seeded onto the laser-patterned surface and the coverage by cells was evaluated after 3-21 days of cultivation by means of scanning electron microscopy. Compared to flat surfaces, the cell density on the microstructures was significantly lower, the coverage was incomplete, and the cells had a clearly different morphology. The best results regarding suppression of cell growth were obtained on spike structures which were additionally electrochemically oxidized under acidic conditions. Cell cultivation with additional shear stress could reduce further the number of adherent cells.

  1. Growth and Potential Damage of Human Bone-Derived Cells Cultured on Fresh and Aged C60/Ti Films

    Science.gov (United States)

    Kopova, Ivana; Lavrentiev, Vasily; Vacik, Jiri; Bacakova, Lucie

    2015-01-01

    Thin films of binary C60/Ti composites, with various concentrations of Ti ranging from ~ 25% to ~ 70%, were deposited on microscopic glass coverslips and were tested for their potential use in bone tissue engineering as substrates for the adhesion and growth of bone cells. The novelty of this approach lies in the combination of Ti atoms (i.e., widely used biocompatible material for the construction of stomatological and orthopedic implants) with atoms of fullerene C60, which can act as very efficient radical scavengers. However, fullerenes and their derivatives are able to generate harmful reactive oxygen species and to have cytotoxic effects. In order to stabilize C60 molecules and to prevent their possible cytotoxic effects, deposition in the compact form of Ti/C60 composites (with various Ti concentrations) was chosen. The reactivity of C60/Ti composites may change in time due to the physicochemical changes of molecules in an air atmosphere. In this study, we therefore tested the dependence between the age of C60/Ti films (from one week to one year) and the adhesion, morphology, proliferation, viability, metabolic activity and potential DNA damage to human osteosarcoma cells (lines MG-63 and U-2 OS). After 7 days of cultivation, we did not observe any negative influence of fresh or aged C60/Ti layers on cell behavior, including the DNA damage response. The presence of Ti atoms resulted in improved properties of the C60 layers, which became more suitable for cell cultivation. PMID:25875338

  2. TiO2 nanotube-based dye solar cell research in South Africa

    CSIR Research Space (South Africa)

    Cummings, F

    2009-10-01

    Full Text Available Vertically orientated titanium dioxide (TiO2) nanotubes hold great potential for application in dye-sensitized solar cells (DSCs) as they provide an unscathed, one-dimensional transport route for photo-generated charge carriers, thereby increasing...

  3. Process optimization of dye-sensitized solar cells using TiO2 ...

    Indian Academy of Sciences (India)

    2017-11-23

    Nov 23, 2017 ... TiO2 attached closely on the graphene flake is possible to ... spacer between the two electrodes of the cell. Iodide-based .... Doping of high concentration of .... [34] Huang Q, Tian S, Zeng D, Wang X, Song W, Li Y et al 2013.

  4. Optimizing TiO2 nanotube top geometry for use in dye-sensitized solar cells.

    Science.gov (United States)

    Mir, Nooshin; Lee, Kiyoung; Paramasivam, Indhumati; Schmuki, Patrik

    2012-09-17

    Recombination dynamics: For TiO(2) nanotube-based dye-sensitized solar cells, the efficiency can be drastically enhanced by a synergetic effect that occurs when using nanowire-ended nanotubes in combination with an adequate nanoparticle decoration (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Eco-friendly synthesis of TiO2, Au and Pt doped TiO2 nanoparticles for dye sensitized solar cell applications and evaluation of toxicity

    Science.gov (United States)

    Gopinath, K.; Kumaraguru, S.; Bhakyaraj, K.; Thirumal, S.; Arumugam, A.

    2016-04-01

    Driven by the demand of pure TiO2, Au and Pt doped TiO2 NPs were successfully synthesized using Terminalia arjuna bark extract. The eco-friendly synthesized NPs were characterized by UV-Vis-DRS, ATR-FT-IR, PL, XRD, Raman, SEM with EDX and TEM analysis. The synthesized NPs were investigation for dye sensitized solar cell applications. UV-Vis-Diffused Reflectance Spectra clearly showed that the expected TiO2 inter band absorption below 306 nm, incorporation of gold shows surface plasma resonant (SPR) near 555 nm and platinum incorporated TiO2 NPs shows absorbance at 460 nm. The energy conversion efficiency for Au doped TiO2 NPs when compared to pure and Pt doped TiO2 NPs. In addition to that, Au noble metal present TiO2 matrix and an improve open-circuit voltage (Voc) of DSSC. Synthesized NPs was evaluated into antibacterial and antifungal activities by disk diffusion method. It is observed that NPs have not shown any activities in all tested bacterial and fungal strains. In this eco-friendly synthesis method to provide non toxic and environmental friendly nanomaterials can be used for solar energy device application.

  6. TiO2 nanofiber solid-state dye sensitized solar cells with thin TiO2 hole blocking layer prepared by atomic layer deposition

    International Nuclear Information System (INIS)

    Li, Jinwei; Chen, Xi; Xu, Weihe; Nam, Chang-Yong; Shi, Yong

    2013-01-01

    We incorporated a thin but structurally dense TiO 2 layer prepared by atomic layer deposition (ALD) as an efficient hole blocking layer in the TiO 2 nanofiber based solid-state dye sensitized solar cell (ss-DSSC). The nanofiber ss-DSSCs having ALD TiO 2 layers displayed increased open circuit voltage, short circuit current density, and power conversion efficiency compared to control devices with blocking layers prepared by spin-coating liquid TiO 2 precursor. We attribute the improved photovoltaic device performance to the structural integrity of ALD-coated TiO 2 layer and consequently enhanced hole blocking effect that results in reduced dark leakage current and increased charge carrier lifetime. - Highlights: • TiO 2 blocking locking layer prepared by atomic layer deposition (ALD) method. • ALD-coated TiO 2 layer enhanced hole blocking effect. • ALD blocking layer improved the voltage, current and efficiency. • ALD blocking layer reduced dark leakage current and increased electron lifetime

  7. TiO{sub 2} nanofiber solid-state dye sensitized solar cells with thin TiO{sub 2} hole blocking layer prepared by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jinwei; Chen, Xi; Xu, Weihe [Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Nam, Chang-Yong, E-mail: cynam@bnl.gov [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 (United States); Shi, Yong, E-mail: Yong.Shi@stevens.edu [Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)

    2013-06-01

    We incorporated a thin but structurally dense TiO{sub 2} layer prepared by atomic layer deposition (ALD) as an efficient hole blocking layer in the TiO{sub 2} nanofiber based solid-state dye sensitized solar cell (ss-DSSC). The nanofiber ss-DSSCs having ALD TiO{sub 2} layers displayed increased open circuit voltage, short circuit current density, and power conversion efficiency compared to control devices with blocking layers prepared by spin-coating liquid TiO{sub 2} precursor. We attribute the improved photovoltaic device performance to the structural integrity of ALD-coated TiO{sub 2} layer and consequently enhanced hole blocking effect that results in reduced dark leakage current and increased charge carrier lifetime. - Highlights: • TiO{sub 2} blocking locking layer prepared by atomic layer deposition (ALD) method. • ALD-coated TiO{sub 2} layer enhanced hole blocking effect. • ALD blocking layer improved the voltage, current and efficiency. • ALD blocking layer reduced dark leakage current and increased electron lifetime.

  8. Silver Nanoparticles in Alveolar Bone Surgery Devices

    Directory of Open Access Journals (Sweden)

    Stefano Sivolella

    2012-01-01

    Full Text Available Silver (Ag ions have well-known antimicrobial properties and have been applied as nanostrategies in many medical and surgical fields, including dentistry. The use of silver nanoparticles (Ag NPs may be an option for reducing bacterial adhesion to dental implant surfaces and preventing biofilm formation, containing the risk of peri-implant infections. Modifying the structure or surface of bone grafts and membranes with Ag NPs may also prevent the risk of contamination and infection that are common when alveolar bone augmentation techniques are used. On the other hand, Ag NPs have revealed some toxic effects on cells in vitro and in vivo in animal studies. In this setting, the aim of the present paper is to summarize the principle behind Ag NP-based devices and their clinical applications in alveolar bone and dental implant surgery.

  9. Effects of Homogenization Scheme of TiO2 Screen-Printing Paste for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Seigo Ito

    2012-01-01

    Full Text Available TiO2 porous electrodes have been fabricated for photoelectrodes in dye-sensitized solar cells (DSCs using TiO2 screen-printing paste from nanocrystalline TiO2 powder dried from the synthesized sol. We prepared the TiO2 screen-printing paste by two different methods to disperse the nanocrystalline TiO2 powder: a “ball-milling route” and a “mortal-grinding route.” The TiO2 ball-milling (TiO2-BM route gave monodisperse TiO2 nanoparticles, resulting in high photocurrent density (14.2 mA cm−2 and high photoconversion efficiency (8.27%. On the other hand, the TiO2 mortal-grinding (TiO2-MG route gave large aggregate of TiO2 nanoparticles, resulting in low photocurrent density (11.5 mA cm−2 and low photoconversion efficiency (6.43%. To analyze the photovoltaic characteristics, we measured the incident photon-to-current efficiency, light absorption spectroscopy, and electrical impedance spectroscopy of DSCs.

  10. Influence of the Porosity of the TiO2 Film on the Performance of the Perovskite Solar Cell

    Directory of Open Access Journals (Sweden)

    Xiaodan Sun

    2017-01-01

    Full Text Available The structure of mesoporous TiO2 (mp-TiO2 films is crucial to the performance of mesoporous perovskite solar cells (PSCs. In this study, we fabricated highly porous mp-TiO2 films by doping polystyrene (PS spheres in TiO2 paste. The composition of the perovskite films was effectively improved by modifying the mass fraction of the PS spheres in the TiO2 paste. Due to the high porosity of the mp-TiO2 film, PbI2 and CH3NH3I could sufficiently infiltrate into the network of the mp-TiO2 film, which ensured a more complete transformation to CH3NH3PbI3. The surface morphology of the mp-TiO2 film and the photoelectric performance of the perovskite solar cells were investigated. The results showed that an increase in the porosity of the mp-TiO2 film resulted in an improvement in the performance of the PSCs. The best device with the optimized mass fraction of 1.0 wt% PS in TiO2 paste exhibited an efficiency of 12.69%, which is 25% higher than the efficiency of the PSCs without PS spheres.

  11. Structure of the T cell receptor in a Ti alpha V beta 2, alpha V beta 8-positive T cell line

    DEFF Research Database (Denmark)

    Hou, X; Dietrich, J; Kuhlmann, J

    1994-01-01

    not known; however, it has been suggested that each TcR contains two Ti dimers. To gain insight into the structure of the TcR we constructed a Ti alpha V beta 2, alpha V beta 8-positive T cell line which expressed the endogenous human TiV beta 8 and the transfected mouse TiV beta 2 both in association......The T cell receptor (TcR) is composed of at least six different polypeptide chains consisting of the clonotypic Ti heterodimer (Ti alpha beta or Ti gamma delta) and the noncovalently associated CD3 chains (CD3 gamma delta epsilon zeta). The exact number of subunits constituting the TcR is still...... with the endogenous Ti alpha and CD3 chains at the cell surface. Preclearing experiments with radioiodinated cell lysate prepared with digitonin lysis buffer demonstrated that depleting the lysate of Ti alpha V beta 8 by immunoprecipitation with anti V beta 8 monoclonal antibody (mAb) did not reduce the amount of Ti...

  12. Comparative study of the effects of PM1-induced oxidative stress on autophagy and surfactant protein B and C expressions in lung alveolar type II epithelial MLE-12 cells.

    Science.gov (United States)

    Bai, Ru; Guan, Longfei; Zhang, Wei; Xu, Jinxia; Rui, Wei; Zhang, Fang; Ding, Wenjun

    2016-12-01

    There is a strong link between smaller air pollution particles and a range of serious health conditions. Thus, there is a need for understanding the impacts of airborne fine particulate matter (PM) with an aerodynamic diameter of PM1) on lung alveolar epithelial cells. In the present study, mouse lung epithelial type II cell MLE-12 cells were used to examine the intracellular oxidative responses and the surfactant protein expressions after exposure to various concentrations of PM1 collected from an urban site and a steel-factory site (referred as uPM1 and sPM1 hereafter, respectively). Physicochemical characterization of PM1 was performed by using scanning electron microscopy and transmission electron microscopy. Cytotoxicity and autophagy induced by PM1 were assessed by using comprehensive approaches after MLE-12 cells were exposed to different concentrations of PM1 for various times. Expression of surfactant proteins B and C in MLE-12 cells was determined by Western blotting. All of the tested PM1 induced cytotoxicity evidenced by significant decrease of cell viability and increase of lactate dehydrogenase (LDH) release in a time- and concentration-dependent manner in the exposed cells compared with the unexposed cells. A similar pattern of increase of intercellular reactive oxygen species (ROS) generation and decrease of superoxide dismutase (SOD) and catalase (CAT) activities was also observed. PM1-induced autophagy was evidenced by an increase in microtubule-associated protein light chain-3 (LC3) puncta, accumulation of LC3II, and increased levels of beclin1. Data from Western blotting showed significant decrease of surfactant protein B and C expressions. Relatively high concentrations of transition metals, including Fe, Cu and Mn, may be responsible for the higher toxicity of sPM1 compared with uPM1. Moreover, pretreatment with N-acetylcysteine (NAC) or Chelex (a metal chelating agent, which removes a large suite of metals from PM1) prevented the increase of

  13. Fabrication and characterization of perovskite-type solar cells with Nb-doped TiO{sub 2} layers

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Jo; Oku, Takeo, E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi; Akiyama, Tsuyoshi [The University of Shiga Prefecture, Hikone, Shiga 522-8533 (Japan)

    2016-02-01

    Organic-inorganic hybrid heterojunction solar cells containing perovskite CH{sub 3}NH{sub 3}PbI{sub 3} using Nb-doped TiO{sub 2} as an electron-transporting layer were fabricated and characterized. Nb-doped TiO{sub 2} layer showed an improvement of the short-circuit current density and power conversion efficiency using Ti{sub 0.95}Nb{sub 0.05}O{sub 2}.

  14. Sphingosine 1-phosphate-induced ICAM-1 expression via NADPH oxidase/ROS-dependent NF-kappaB cascade on human pulmonary alveolar epithelial cells

    Directory of Open Access Journals (Sweden)

    Chin-Chung eLin

    2016-03-01

    Full Text Available The intercellular adhesion molecule-1 (ICAM-1 expression is frequently correlated with the lung inflammation. A bioactive sphingolipid metabolite, sphingosine-1-phosphate (S1P, was involved in inflammation through the adhesion molecules induction, and then caused lung injury. However, the transduction mechanisms of the S1P stimulation to induce ICAM-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs remain unclear. Here, we demonstrated that exposure of HPAEpiCs to S1P significantly induces ICAM-1 expression leading to increase monocyte adhesion on the surface of HPAEpiCs. These phenomena were effectively attenuated by pretreatments with series of inhibitors such as Rottlerin (PKCdelta, PF431396 (PYK2, diphenyleneiodonium chloride (DPI, apocynin (NADPH oxidase, Edaravone (ROS, and Bay11-7082 (NF-kappaB. Consistently, knockdown with siRNA transfection of PKCdelta, PYK2, p47phox, and p65 exhibited the same results. Pretreatment with both Gq-coupled receptor antagonist (GPA2A and Gi/o-coupled receptor antagonist (GPA2 also blocked S1P-induced ICAM-1 protein and mRNA expression. We observed that S1P induced PYK2 activation via a Gq-coupled receptor/PKCdelta-dependent pathway. In addition, S1P induced NADPH oxidase activation and intracellular ROS generation, which were also reduced by Rottlerin or PF431396. We demonstrated that S1P induced NF-kappaB p65 phosphorylation and translocation from the cytosol to the nucleus in HPAEpiCs, which was inhibited by Rottlerin, PF431396, APO, DPI, or Edaravone. In the in vitro study, we established that S1P induced monocyte adhesion via an ICAM-1-dependent pathway. In the in vivo study, we found that S1P induced ICAM-1 protein and mRNA levels in the lung fractions, pulmonary hematoma, and leukocyte (mainly eosinophils and neutrophils count in bronchoalveolar lavage (BAL fluid in mice via a PKCdelta/PYK2/NADPH oxidase/ROS/NF-kappaB signaling pathway. We concluded that S1P may induce lung

  15. Sphingosine 1-Phosphate-Induced ICAM-1 Expression via NADPH Oxidase/ROS-Dependent NF-κB Cascade on Human Pulmonary Alveolar Epithelial Cells

    Science.gov (United States)

    Lin, Chih-Chung; Yang, Chien-Chung; Cho, Rou-Ling; Wang, Chen-Yu; Hsiao, Li-Der; Yang, Chuen-Mao

    2016-01-01

    The intercellular adhesion molecule-1 (ICAM-1) expression is frequently correlated with the lung inflammation. In lung injury, sphingosine-1-phosphate (S1P, bioactive sphingolipid metabolite), participate gene regulation of adhesion molecule in inflammation progression and aggravate tissue damage. To investigate the transduction mechanisms of the S1P in pulmonary epithelium, we demonstrated that exposure of HPAEpiCs (human pulmonary alveolar epithelial cells) to S1P significantly induces ICAM-1 expression leading to increase monocyte adhesion on the surface of HPAEpiCs. These phenomena were effectively attenuated by pretreatments with series of inhibitors such as Rottlerin (PKCδ), PF431396 (PYK2), diphenyleneiodonium chloride (DPI), apocynin (NADPH oxidase), Edaravone (ROS), and Bay11-7082 (NF-κB). Consistently, knockdown with siRNA transfection of PKCδ, PYK2, p47phox, and p65 exhibited the same results. Pretreatment with both Gq-coupled receptor antagonist (GPA2A) and Gi/o-coupled receptor antagonist (GPA2) also blocked the upregulation of ICAM-1 protein and mRNA induced by S1P. We observed that S1P induced PYK2 activation via a Gq-coupled receptor/PKCδ-dependent pathway. In addition, S1P induced NADPH oxidase activation and intracellular ROS generation, which were also reduced by Rottlerin or PF431396. We demonstrated that S1P induced NF-κB p65 phosphorylation and nuclear translocation in HPAEpiCs. Activated NF-κB was blocked by Rottlerin, PF431396, APO, DPI, or Edaravone. Besides, the results of monocyte adhesion assay indicated that S1P-induced ICAM-1 expression on HPAEpiCs can enhance the monocyte attachments. In the S1P-treated mice, we found that the levels of ICAM-1 protein and mRNA in the lung fractions, the pulmonary hematoma and leukocyte count in bronchoalveolar lavage fluid were enhanced through a PKCδ/PYK2/NADPH oxidase/ROS/NF-κB signaling pathway. We concluded that S1P-accelerated lung damage is due to the ICAM-1 induction associated with

  16. The modulation of stem cell behaviors by functionalized nanoceramic coatings on Ti-based implants

    Directory of Open Access Journals (Sweden)

    Xiangmei Liu

    2016-09-01

    Full Text Available Nanoceramic coating on the surface of Ti-based metallic implants is a clinical potential option in orthopedic surgery. Stem cells have been found to have osteogenic capabilities. It is necessary to study the influences of functionalized nanoceramic coatings on the differentiation and proliferation of stem cells in vitro or in vivo. In this paper, we summarized the recent advance on the modulation of stem cells behaviors through controlling the properties of nanoceramic coatings, including surface chemistry, surface roughness and microporosity. In addition, mechanotransduction pathways have also been discussed to reveal the interaction mechanisms between the stem cells and ceramic coatings on Ti-based metals. In the final part, the osteoinduction and osteoconduction of ceramic coating have been also presented when it was used as carrier of BMPs in new bone formation.

  17. Advantages of using Ti-mesh type electrodes for flexible dye-sensitized solar cells

    International Nuclear Information System (INIS)

    He Weizhen; Kim, Hyung-Kook; Hwang, Yoon-Hwae; Qiu Jijun; Zhuge Fuwei; Li Xiaomin; Lee, Jae-Ho; Kim, Yang-Do

    2012-01-01

    We used Ti meshes for both the photoanodes and counter electrodes of dye-sensitized solar cells (DSSCs) to improve the flexibility and conductivity of the electrodes. These mesh type electrodes showed good transparency and high bendability when subjected to an external force. We demonstrated the advantages of cells using such electrodes compared to traditional transparent conducting oxide based electrodes and back side illuminated DSSCs, such as low sheet resistance, elevated photo-induced current and enhanced sunlight utilization. Nanotube layers of different thicknesses were investigated to determine their effect on the photovoltaic parameters of the cell. The overall efficiency of the best cells was approximately 5.3% under standard air mass 1.5 global (AM 1.5 G) solar conditions. Furthermore, the DSSCs showed an efficiency of approximately 3.15% due to the all Ti-mesh type electrodes even after illumination from the back side. (paper)

  18. TiO{sub 2} nanoparticle-induced ROS correlates with modulated immune cell function

    Energy Technology Data Exchange (ETDEWEB)

    Maurer-Jones, Melissa A.; Christenson, Jenna R.; Haynes, Christy L., E-mail: chaynes@umn.edu [University of Minnesota, Department of Chemistry (United States)

    2012-12-15

    Design of non-toxic nanoparticles will be greatly facilitated by understanding the nanoparticle-cell interaction mechanism on a cell function level. Mast cells are important cells for the immune system's first line of defense, and we can utilize their exocytotic behavior as a model cellular function as it is a conserved process across cell types and species. Perturbations in exocytosis can also have implications for whole organism health. One proposed mode of toxicity is nanoparticle-induced reactive oxygen species (ROS), particularly for titanium dioxide (TiO{sub 2}) nanoparticles. Herein, we have correlated changes in ROS with the perturbation of the critical cell function of exocytosis, using UV light to induce greater levels of ROS in TiO{sub 2} exposed cells. The primary culture mouse peritoneal mast cells (MPMCs) were exposed to varying concentrations of TiO{sub 2} nanoparticles for 24 h. ROS content was determined using 2,7-dihydrodichlorofluorescein diacetate (DCFDA). Cellular viability was determined with the MTT and Trypan blue assays, and exocytosis was measured by the analytical electrochemistry technique of carbon-fiber microelectrode amperometry. MPMCs exposed to TiO{sub 2} nanoparticles experienced a dose-dependent increase in total ROS content. While there was minimal impact of ROS on cellular viability, there is a correlation between ROS amount and exocytosis perturbation. As nanoparticle-induced ROS increases, there is a significant decrease (45 %) in the number of serotonin molecules being released during exocytosis, increase (26 %) in the amount of time for each exocytotic granule to release, and decrease (28 %) in the efficiency of granule trafficking and docking. This is the first evidence that nanoparticle-induced ROS correlates with chemical messenger molecule secretion, possibly making a critical connection between functional impairment and mechanisms contributing to that impairment.

  19. Improved performance of dye-sensitized solar cell based on TiO{sub 2} photoanode with FTO glass and film both treated by TiCl{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jinlun [School of Materials and Energy, Guangdong University of Technology, Guangzhou Higher Education Mega Center 100#, Guangzhou, 510006 (China); Zhang, Haiyan, E-mail: hyzhang@gdut.edu.cn [School of Materials and Energy, Guangdong University of Technology, Guangzhou Higher Education Mega Center 100#, Guangzhou, 510006 (China); Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, Guangzhou, 510006 (China); Wang, Wenguang, E-mail: wenguangwang2005@163.com [School of Materials and Energy, Guangdong University of Technology, Guangzhou Higher Education Mega Center 100#, Guangzhou, 510006 (China); Key Laboratory of Renewable Energy, Chinese Academy of Sciences, Guangzhou, 510640 (China); Qian, Yannan; Li, Zhenghui [School of Materials and Energy, Guangdong University of Technology, Guangzhou Higher Education Mega Center 100#, Guangzhou, 510006 (China)

    2016-11-01

    The dye-sensitized solar cell (DSSC) based on TiO{sub 2} photoanode with FTO glass and TiO{sub 2} film co-treated by TiCl{sub 4} were fabricated. The effects of TiCl{sub 4} treatment on the photovoltaic performance of the DSSCs were investigated. TiCl{sub 4} treatment of the FTO glass resulted in the formation of a compact TiO{sub 2} thin layer on its surface, which could increase the electron collection efficiency. Meanwhile, TiCl{sub 4} treatment of the TiO{sub 2} film could fill gaps between nanoparticles in the TiO{sub 2} film, leading to better electron transfer. These advantages make the DSSC exhibit a highest conversion efficiency of 3.34% under a simulated solar irradiation with an intensity of 100 mW/cm{sup 2} (1 sun), increased by 38% compared with that of the untreated DSSC.

  20. Controllable preparation of TiO{sub 2} nanowire arrays on titanium mesh for flexible dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenwu; Lu, Hui; Zhang, Mei; Guo, Min, E-mail: guomin@ustb.edu.cn

    2015-08-30

    Graphical abstract: TiO{sub 2} nanowire arrays with controlled morphology and density have been synthesized on Ti mesh substrates by hydrothermal approach for flexible dye-sensitized solar cells which showed well photovoltaic efficiency of 3.42%. - Highlights: • Flexible titanium mesh was first used for hydrothermal preparation of TiO{sub 2} NWAs. • The formation mechanism of the TiO{sub 2} nanostructures was discussed. • The density, average diameter, and morphology of TiO{sub 2} NWAs can be controlled. • The effects of the sensitization temperature and time on the properties were studied. - Abstract: TiO{sub 2} nanowire arrays (NWAs) with an average diameter of 80 nm have been successfully synthesized on titanium (Ti) mesh substrates via hydrothermal method. The effects of preparing conditions such as concentration of NaOH solution, reaction time, and hydrothermal temperature on the growth of TiO{sub 2} nanoarrays and its related photovoltaic properties were systematically investigated by scanning electron microscopy, X-ray diffraction, and photovoltaic properties test. The growth mechanism of the Ti mesh-supported TiO{sub 2} nanostructures was discussed in detail. Moreover, a parametric study was performed to determine the optimized temperature and time of the dye sensitized process for the flexible dye-sensitized solar cell (DSSC). It is demonstrated that hydrothermal parameters had obvious influence on the morphology and growth density of the as-prepared TiO{sub 2} nanoarrays. In addition, the performance of the flexible DSSC depended strongly on the sensitization temperature and time. By utilizing Ti mesh-supported TiO{sub 2} NWAs (with a length of about 14 μm) as a photoanode, the flexible DSSC with a short circuit current density of 10.49 mA cm{sup −2}, an open-circuit voltage of 0.69 V, and an overall power conversion efficiency of 3.42% was achieved.

  1. Controllable preparation of TiO2 nanowire arrays on titanium mesh for flexible dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Liu, Wenwu; Lu, Hui; Zhang, Mei; Guo, Min

    2015-01-01

    Graphical abstract: TiO 2 nanowire arrays with controlled morphology and density have been synthesized on Ti mesh substrates by hydrothermal approach for flexible dye-sensitized solar cells which showed well photovoltaic efficiency of 3.42%. - Highlights: • Flexible titanium mesh was first used for hydrothermal preparation of TiO 2 NWAs. • The formation mechanism of the TiO 2 nanostructures was discussed. • The density, average diameter, and morphology of TiO 2 NWAs can be controlled. • The effects of the sensitization temperature and time on the properties were studied. - Abstract: TiO 2 nanowire arrays (NWAs) with an average diameter of 80 nm have been successfully synthesized on titanium (Ti) mesh substrates via hydrothermal method. The effects of preparing conditions such as concentration of NaOH solution, reaction time, and hydrothermal temperature on the growth of TiO 2 nanoarrays and its related photovoltaic properties were systematically investigated by scanning electron microscopy, X-ray diffraction, and photovoltaic properties test. The growth mechanism of the Ti mesh-supported TiO 2 nanostructures was discussed in detail. Moreover, a parametric study was performed to determine the optimized temperature and time of the dye sensitized process for the flexible dye-sensitized solar cell (DSSC). It is demonstrated that hydrothermal parameters had obvious influence on the morphology and growth density of the as-prepared TiO 2 nanoarrays. In addition, the performance of the flexible DSSC depended strongly on the sensitization temperature and time. By utilizing Ti mesh-supported TiO 2 NWAs (with a length of about 14 μm) as a photoanode, the flexible DSSC with a short circuit current density of 10.49 mA cm −2 , an open-circuit voltage of 0.69 V, and an overall power conversion efficiency of 3.42% was achieved

  2. Interface Passivation Effects on the Photovoltaic Performance of Quantum Dot Sensitized Inverse Opal TiO₂ Solar Cells.

    Science.gov (United States)

    Hori, Kanae; Zhang, Yaohong; Tusamalee, Pimsiri; Nakazawa, Naoki; Yoshihara, Yasuha; Wang, Ruixiang; Toyoda, Taro; Hayase, Shuzi; Shen, Qing

    2018-06-25

    Quantum dot (QD)-sensitized solar cells (QDSSCs) are expected to achieve higher energy conversion efficiency than traditional single-junction silicon solar cells due to the unique properties of QDs. An inverse opal (IO)-TiO₂ (IO-TiO₂) electrode is useful for QDSSCs because of its three-dimensional (3D) periodic nanostructures and better electrolyte penetration compared to the normal nanoparticles (NPs)-TiO₂ (NPs-TiO₂) electrode. We find that the open-circuit voltages V oc of the QDSSCs with IO-TiO₂ electrodes are higher than those of QDSSCs with NPs-TiO₂ electrodes. One important strategy for enhancing photovoltaic conversion efficiency of QDSSCs with IO-TiO₂ electrodes is surface passivation of photoanodes using wide-bandgap semiconducting materials. In this study, we have proposed surface passivation on IO-TiO₂ with ZnS coating before QD deposition. The efficiency of QDSSCs with IO-TiO₂ electrodes is largely improved (from 0.74% to 1.33%) because of the enhancements of V oc (from 0.65 V to 0.74 V) and fill factor ( FF ) (from 0.37 to 0.63). This result indicates that ZnS passivation can reduce the interfacial recombination at the IO-TiO₂/QDs and IO-TiO₂/electrolyte interfaces, for which two possible explanations can be considered. One is the decrease of recombination at IO-TiO₂/electrolyte interfaces, and the other one is the reduction of the back-electron injection from the TiO₂ electrode to QDs. All of the above results are effective for improving the photovoltaic properties of QDSSCs.

  3. Synthesis of TiO2 nanotubes with ZnO nanoparticles to achieve antibacterial properties and stem cell compatibility

    Science.gov (United States)

    Liu, Wenwen; Su, Penglei; Chen, Su; Wang, Na; Ma, Yuanping; Liu, Yiran; Wang, Jinshu; Zhang, Zhenting; Li, Hongyi; Webster, Thomas J.

    2014-07-01

    To endow titanium (Ti) with antibacterial properties, different concentrations of zinc oxide (ZnO) nanoparticles were decorated on anodized titanium dioxide (TiO2) nanotubes by a simple hydrothermal treatment method. The particle sizes of ZnO, which were evenly distributed and tightly adherent to the walls of the Ti nanotubes, ranged from 20-50 nm. Results from this study showed that Zn was released from the TiO2 nanotubes in a constant, slow, and biologically inspired manner. Importantly, the results showed that the ZnO decorated TiO2 nanotubular samples inhibited Streptococcus mutants and Porphyromonas gingivalis growth compared to control unmodified Ti samples. Specifically, S. mutants and P. gingivalis growth were both reduced 45-85% on the ZnO decorated Ti samples compared to Ti controls after 7 days of culture. When examining the mechanism of action, it has been further found for the first time that the ZnO decorated Ti samples inhibited the expression of Streptococcus mutans bacterial adhesion genes. Lastly, the results showed that the same samples which decreased bacterial growth the most (0.015 M precursor Zn(NO3)2 samples) did not inhibit mesenchymal stem cell growth compared to Ti controls for up to 7 days. In summary, results from this study showed that compared to plain TiO2 nanotubes, TiO2 decorated with 0.015 M ZnO provided unprecedented antibacterial properties while maintaining the stem cell proliferation capacity necessary for enhancing the use of Ti in numerous medical applications, particularly in dentistry.

  4. Mesoporous TiO2 : an alternative material for PEM fuel cells catalyst support

    Energy Technology Data Exchange (ETDEWEB)

    Do, T.B. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Materials Science; Ruthkosky, M.; Cai, M. [General Motors, Warren, MI (United States). Research and Development Center

    2008-07-01

    This paper discussed the feasibility of using an alternative catalyst support material to replace carbon in proton exchange membrane (PEM) fuel cells. The alternative catalyst support material requires a high surface area with a large porosity but must have comparable conductivity with carbon. A mesoporous titanium oxide (TiO2) material produced by coprecipitation was introduced. The conductivity of the material is about one order of that of carbon. The 8 mole per cent Nb-doped TiO2 was formed and deposited on the surface of a nano polystyrene (PS) template via the hydrolysis of a co-solution of Ti(OC4H9)4 and Nb(OC2H5)5. The removal of PS by heat treatment produced porous structure of TiO2 with the appearance of 3 different pore types, notably open pore, ink-pot pores and closed pores. TiO2 formed from the rutile phase, allowing a lower activation temperature at 850 degrees C in a hydrogen atmosphere. The pore structures were retained after this heat treatment. The BET surface area was 116 m{sup 2}/g, porosity was 22 per cent and the average pore size was 159 angstrom. The conductivity improved considerably from almost non-conductive to one order of that of carbon.

  5. MRI of cerebral alveolar echinococcosis

    International Nuclear Information System (INIS)

    Tunaci, M.; Tunaci, A.; Engin, G.; Oezkorkmaz, B.; Ahishali, B.; Rozanes, I.

    1999-01-01

    Cerebral alveolar echinococcosis is rare. We report a case with multiple intracranial masses which show cauliflower-like contrast enhancement pattern on MRI. The lesions originated from hepatic involvement with invasion of the inferior vena cava. (orig.)

  6. Electron Beam Evaporated TiO2 Layer for High Efficiency Planar Perovskite Solar Cells on Flexible Polyethylene Terephthalate Substrates

    KAUST Repository

    Qiu, Weiming; Paetzold, Ulrich W; Gehlhaar, Robert; Smirnov, Vladimir; Boyen, Hans-Gerd; Tait, Jeffrey Gerhart; Conings, Bert; Zhang, Weimin; Nielsen, Christian; McCulloch, Iain; Froyen, Ludo; Heremans, Paul; Cheyns, David

    2015-01-01

    The TiO2 layer made by electron beam (e-beam) induced evaporation is demonstrated as electron transport layer (ETL) in high efficiency planar junction perovskite solar cells. The temperature of the substrate and the thickness of the TiO2 layer can

  7. Eosin yellowish dye sensitized TiO2 solar cell with PEG/PEO/LiI/I2 as electrolyte

    Science.gov (United States)

    Kanmani, S. S.; Umapathy, S.; Ramachandran, K.

    2012-06-01

    Eosin Yellowish dye sensitized TiO2 nanoparticles (NP) and nanowires (NW) are employed as photo anodes in dye sensitized solar cells with PEO/PEG/LiI/I2 as electrolyte. Material characterization by XRD and SEM confirms the formation of anatase phased TiO2 NP and NW. Effective quenching of UV emission in TiO2 NW than NP is a consequence of reduction in recombination rate, which directly favours for better solar conversion efficiency. The photovoltaic performance of TiO2 NW with an overall conversion efficiency of 0.31 % is better than NP, which is the outcome of improved electron transport in NW.

  8. HOS cell adhesion on Ti6Al4V ELI texturized by CO2 laser

    Science.gov (United States)

    Sandoval-Amador, A.; Bayona–Alvarez, Y. M.; Carreño Garcia, H.; Escobar-Rivero, P.; Y Peña-Ballesteros, D.

    2017-12-01

    In this work, the response of HOS cells on Ti6Al4V ELI textured surfaces by a CO2 laser was evaluated. The test surfaces were; smooth Ti6Al4V, used as the control, and four textured surfaces with linear geometry. These four surfaces had different separation distances between textured lines, D1 (1000 microns), D2 (750 microns), D3 (500 microns) and D4 (250 microns). Toxicity of textured surfaces was assessed by MTT and the cellular adhesion test was performed using HOS ATCC CRL 1543 line cells. This test was done after 5 days of culture in a RPMI 1640 medium supplemented with 10% fetal bovine serum and 1% antibiotics. The results showed that the linear textures present 23% toxicity after 30 days of incubation, nevertheless, the adhesion tests results are inconclusive in such conditions and therefore the effect of the line separation on the cell adhesion cannot be determined.

  9. Controlled synthesis of TiO2-B nanowires and nanoparticles for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Qi Lihong; Liu Yongjun; Li Chunyan

    2010-01-01

    Controllable synthesis of the TiO 2 -B nanowires (NWs) and nanoparticles (NPs) had been achieved via a facile hydrothermal route, respectively, only by tuning the solution volume. The dye-sensitized solar cells prototypes had been fabricated using TiO 2 -B NW and NP electrodes, respectively. The TiO 2 -B NP cells had higher photocurrent and photoelectrical conversion efficiency than the TiO 2 -B NW cells though the latter exhibited larger photovoltage compared to the former. The key factors such as the photogenerated electron injection drive force, surface defects and the interfacial charge transfer, which determined the photoelectrical properties, had been systematically researched with the surface photovoltage spectra (SPS) and the electrochemical impedance spectra (EIS). The SPS proved that there was larger photoelectron injection drive force in TiO 2 -B NP photoelectrode than that in NW photoelectrode. And the electrochemical impedance spectra (EIS) revealed that TiO 2 -B NP cells had faster interface charge transfer compared to TiO 2 -B NW cells. Both proved that NP cells had the higher photocurrents.

  10. Effect of Ti diffusion on the microstructure of Ge2Sb2Te5 in phase-change memory cell.

    Science.gov (United States)

    Park, Jucheol; Bae, JunSoo

    2015-12-01

    The dependence of the microstructure of Ge2Sb2Te5 (GST) on Ti diffusion into GST by annealing in GST/Ti/TiN phase-change random access memory stack was studied by various transmission electron microscopy (TEM) techniques. The microstructure and crystal structure of GST were identified with high-resolution TEM (HRTEM) and image simulation technique, and the Ti diffusion into GST was revealed by scanning transmission electron microscope-energy-dispersive X-ray spectroscopy analysis. It was observed that Ti atoms of Ti/TiN thin layers were incorporated into GST cell through several thermal annealing steps and they could retard the phase transition from face-centered cubic (FCC) phase into hexagonal close-packed (HCP) phase partially and restrain the increase in grain size. Thus, it is concluded that Ti diffusion can affect the microstructure of GST including the type of the crystal phase and grain size of GST. It was shown that the insertion of diffusion barrier between TiN and GST could block Ti diffusion into GST and make it possible for FCC phase to completely transform into HCP phase. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Hydrogenated TiO{sub 2} film for enhancing photovoltaic properties of solar cells and self-sensitized effect

    Energy Technology Data Exchange (ETDEWEB)

    He, Hongcai; Yang, Kui; Wang, Ning, E-mail: ning-wang@uestc.edu.cn; Luo, Feifei; Chen, Haijun [State Key Laboratory of Electronic Thin Films and Integrated Devices and School of Microelectronics and Solid-State Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2013-12-07

    Hydrogenated TiO{sub 2} film was obtained by annealing TiO{sub 2} film at 350 °C for 2 h with hydrogen, and TiO{sub 2} films were prepared by screen printing on fluorine-doped tin oxide glass. Structural characterization by X-ray diffraction and electron microscopy did not show obvious difference between hydrogenated TiO{sub 2} film and pristine TiO{sub 2} film. Through optical and electrochemical characterization, the hydrogenated TiO{sub 2} film showed enhanced absorption and narrowed band gap, as well as reduced TiO{sub 2} surface impedance and dark current. As a result, an obviously enhanced photovoltaic effect was observed in the solar cell with hydrogenated TiO{sub 2} as photoanode without adding any dye due to the self-sensitized effect of hydrogenated TiO{sub 2} film, which excited electrons injecting internal conduction band of TiO{sub 2} to generate more photocurrent.

  12. TiO2-enriched polymeric powder coatings support human mesenchymal cell spreading and osteogenic differentiation

    International Nuclear Information System (INIS)

    Mozumder, Mohammad Sayem; Zhu, Jesse; Perinpanayagam, Hiran

    2011-01-01

    Novel polymeric powder coatings (PPC) were prepared by ultrafine powder coating technology and shown to support human mesenchymal cell attachment and growth. PPC surfaces enriched with nano-TiO 2 (nTiO 2 ) showed enhanced cellular responses, and were compared to commercially pure titanium (cpTi). After cell attachment and growth, osteogenic differentiation and bone matrix formation ensures osseointegration for implantable biomaterials. Therefore, the objective of this study was to determine if mesenchymal cells grown on PPC could undergo osteogenic differentiation by inducing Runx2 and bone matrix proteins, and then initiate mineralization. Atomic force microscopy revealed intricate three-dimensional micro-topographies, and the measures of nano-roughness and porosity were similar for all PPC surfaces. Scanning electron microscopy showed that the cells attached and spread out over all of the surfaces. After 1 week in osteogenic media, RT-PCR analysis showed the induction of Runx2, the up-regulation of type I collagen, and the initial detection of alkaline phosphatase and bone sialoprotein. After 4 weeks, Alizarin Red staining showed mineral deposition. However, cell spreading and osteogenic differentiation were significantly (P 2 additives may enhance their performance.

  13. Production of core–shell type conducting FTO/TiO2 photoanode for dye sensitized solar cells

    International Nuclear Information System (INIS)

    Icli, Kerem Cagatay; Yavuz, Halil Ibrahim; Ozenbas, Macit

    2014-01-01

    Core–shell type photoanode composed of electrically conducting fluorine doped tin dioxide (FTO) matrix and TiO 2 shell layer was prepared and applied in dye sensitized solar cells. Effects of fluorine doping on tin dioxide based cells and precursor material on shell layer were investigated. Fluorine doped tin dioxide nanoparticles were synthesized under hydrothermal conditions and resistivity value down to 17 Ω cm was achieved. Cells constructed from FTO nanoparticles show enhanced performance compared to intrinsic SnO 2 . Deposition of thin blocking TiO 2 layers was conducted using ammonium hexafluorotitanate and titanium tetrachloride aqueous solutions for different dipping durations which yielded significant deviations in the layer morphology and affected cell parameters. Best results were obtained with titanium tetrachloride treated cells giving 11.51 mA/cm 2 photocurrent density and they were comparable with that of pure TiO 2 based cells prepared under identical conditions. - Graphical abstract: Core shell type FTO matrix was formed as TiO 2 is the shell material to create a blocking layer between FTO core and the electrolyte for suppressed recombination and efficiency enhancement. Display Omitted - Highlights: • Core–shell type photoanode using conducting FTO matrix and TiO 2 shell was prepared. • FTO nanoparticles having resistivity value down to 17 Ω cm was achieved. • Best cell parameters were obtained with TiCl 4 treated cells. • FTO nanoparticle based cells show enhanced performance compared to intrinsic SnO 2 . • Photocurrent in TiCl 4 treated cells is found as comparable to pure TiO 2 cell

  14. Production of core–shell type conducting FTO/TiO{sub 2} photoanode for dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Icli, Kerem Cagatay [Micro and Nanotechnology Graduate Program, Middle East Technical University, Dumlupinar Bulvari, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications (GUNAM), Middle East Technical University, Dumlupinar Bulvari, 06800 Ankara (Turkey); Yavuz, Halil Ibrahim [Center for Solar Energy Research and Applications (GUNAM), Middle East Technical University, Dumlupinar Bulvari, 06800 Ankara (Turkey); Department of Metallurgical and Materials Engineering, Middle East Technical University, Dumlupinar Bulvari, 06800 Ankara (Turkey); Ozenbas, Macit, E-mail: ozenbas@metu.edu.tr [Center for Solar Energy Research and Applications (GUNAM), Middle East Technical University, Dumlupinar Bulvari, 06800 Ankara (Turkey); Department of Metallurgical and Materials Engineering, Middle East Technical University, Dumlupinar Bulvari, 06800 Ankara (Turkey)

    2014-02-15

    Core–shell type photoanode composed of electrically conducting fluorine doped tin dioxide (FTO) matrix and TiO{sub 2} shell layer was prepared and applied in dye sensitized solar cells. Effects of fluorine doping on tin dioxide based cells and precursor material on shell layer were investigated. Fluorine doped tin dioxide nanoparticles were synthesized under hydrothermal conditions and resistivity value down to 17 Ω cm was achieved. Cells constructed from FTO nanoparticles show enhanced performance compared to intrinsic SnO{sub 2}. Deposition of thin blocking TiO{sub 2} layers was conducted using ammonium hexafluorotitanate and titanium tetrachloride aqueous solutions for different dipping durations which yielded significant deviations in the layer morphology and affected cell parameters. Best results were obtained with titanium tetrachloride treated cells giving 11.51 mA/cm{sup 2} photocurrent density and they were comparable with that of pure TiO{sub 2} based cells prepared under identical conditions. - Graphical abstract: Core shell type FTO matrix was formed as TiO{sub 2} is the shell material to create a blocking layer between FTO core and the electrolyte for suppressed recombination and efficiency enhancement. Display Omitted - Highlights: • Core–shell type photoanode using conducting FTO matrix and TiO{sub 2} shell was prepared. • FTO nanoparticles having resistivity value down to 17 Ω cm was achieved. • Best cell parameters were obtained with TiCl{sub 4} treated cells. • FTO nanoparticle based cells show enhanced performance compared to intrinsic SnO{sub 2}. • Photocurrent in TiCl{sub 4} treated cells is found as comparable to pure TiO{sub 2} cell.

  15. Nanostructured TiO2 microspheres for dye-sensitized solar cells employing a solid state polymer electrolyte

    International Nuclear Information System (INIS)

    Jung, Hun-Gi; Nagarajan, Srinivasan; Kang, Yong Soo; Sun, Yang-Kook

    2013-01-01

    Bimodal mesoporous, anatase TiO 2 microspheres with particle sizes ranging from 0.3 to 2 μm were synthesized using a facile solvothermal method. The photovoltaic performance of TiO 2 microspheres in dye-sensitized solar cells (DSSCs) using a solid state electrolyte was investigated. The solid state electrolyte DSSC device based on the TiO 2 microspheres exhibits an energy conversion efficiency of 4.2%, which is greater than that of commercial P25 TiO 2 (3.6%). The higher photocurrent density was primarily achieved as a result of the greater specific surface area and pore size, which resulted in an increase in the dye uptake of the TiO 2 microspheres and easy transport of solid electrolyte through mesopores. In addition, the greater electron lifetime and superior light scattering ability also enhanced the photovoltaic performance of the TiO 2 microsphere-based, solid state DSSCs

  16. Preparation of Sb2S3 nanocrystals modified TiO2 dendritic structure with nanotubes for hybrid solar cell

    Science.gov (United States)

    Li, Yingpin; Wei, Yanan; Feng, Kangning; Hao, Yanzhong; Pei, Juan; Sun, Bao

    2018-06-01

    Array of TiO2 dendritic structure with nanotubes was constructed on transparent conductive fluorine-doped tin oxide glass (FTO) with titanium potassium oxalate as titanium source. Sb2S3 nanocrystals were successfully deposited on the TiO2 substrate via spin-coating method. Furthermore, TiO2/Sb2S3/P3HT/PEDOT:PSS composite film was prepared by successively spin-coating P3HT and PEDOT:PSS on TiO2/Sb2S3. It was demonstrated that the modification of TiO2 dendritic structure with Sb2S3 could enhance the light absorption in the visible region. The champion hybrid solar cell assembled by TiO2/Sb2S3/P3HT/PEDOT:PSS composite film achieved a power conversion efficiency (PCE) of 1.56%.

  17. TiO2 coated SnO2 nanosheet films for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Cai Fengshi; Yuan Zhihao; Duan Yueqing; Bie Lijian

    2011-01-01

    TiO 2 -coated SnO 2 nanosheet (TiO 2 -SnO 2 NS) films about 300 nm in thickness were fabricated on fluorine-doped tin oxide glass by a two-step process with facile solution-grown approach and subsequent hydrolysis of TiCl 4 aqueous solution. The as-prepared TiO 2 -SnO 2 NSs were characterized by scanning electron microscopy and X-ray diffraction. The performances of the dye-sensitized solar cells (DSCs) with TiO 2 -SnO 2 NSs were analyzed by current-voltage measurements and electrochemical impedance spectroscopy. Experimental results show that the introduction of TiO 2 -SnO 2 NSs can provide an efficient electron transition channel along the SnO 2 nanosheets, increase the short current density, and finally improve the conversion efficiency for the DSCs from 4.52 to 5.71%.

  18. Electrochemical evaluation of Ti/TiO{sub 2}-polyaniline anodes for microbial fuel cells using hypersaline microbial consortia for synthetic-wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Benetton, X.D.; Navarro-Avila, S.G. [Univ. Autonoma de Yucatan, Yucatan (Mexico). Biotecnologia y Bioingenieria; Carrera-Figueiras, C. [Univ. Autonoma de Yucatan, Yucatan (Mexico). Quimica Fundamental y Aplicada

    2010-07-01

    This paper described the development of a titanium (Ti/TiO{sub 2}) polyaniline composite electrode. The electrode was designed for use with a microbial fuel cell (MFC) that generated electricity through the microbial biodegradation of organic compounds. A modified NBAF medium was used with a 20 mM acetate as an electron donor and 53 mM fumarate as an electron acceptor for a period of 96 hours at 37 degrees C. Strains were cultured under strict anaerobic conditions. Two microbial cultures were used: (1) pure cultures of Geobacter sulfur-reducens; and (2) an uncharacterized stable microbial consortia isolated from hypersaline swamp sediments. The anodes were made with an emeraldine form of PANI deposited over Ti/TiO{sub 2} electrodes. Electrochemical impedance spectroscopy (EIS) monitoring was used to determine the open circuit potential of the MFC. Negative real impedances were obtained and reproduced in all systems studied with the Ti/TiO{sub 2}-PANI anodes. The highest power density was obtained using the Geobacter sulfur-reducens culture. Further research is needed to study the mechanisms that contribute to the occurrence of negative real impedances. 23 refs., 1 tab., 5 figs.

  19. Mechanisms of current conduction in Pt/BaTiO3/Pt resistive switching cell

    International Nuclear Information System (INIS)

    Pan, R.K.; Zhang, T.J.; Wang, J.Y.; Wang, J.Z.; Wang, D.F.; Duan, M.G.

    2012-01-01

    The 80-nm-thickness BaTiO 3 (BT) thin film was prepared on the Pt/Ti/SiO 2 /Si substrate by the RF magnetron sputtering technique. The Pt/BT/Pt/Ti/SiO 2 /Si structure was investigated using X-ray diffraction and scanning electron microscopy. The current–voltage characteristic measurements were performed. The bipolar resistive switching behavior was found in the Pt/BT/Pt cell. The current–voltage curves were well fitted in different voltage regions at the high resistance state (HRS) and the low resistance state (LRS), respectively. The conduction mechanisms are concluded to be Ohmic conduction and Schottky emission at the LRS, while space-charge-limited conduction and Poole–Frenkel emission at the HRS. The electroforming and switching processes were explained in terms of the valence change mechanism, in which oxygen vacancies play a key role in forming conducting paths. - Highlights: ►Pt/BaTiO 3 /Pt cell shows the bipolar resistive switching behavior. ►The current–voltage curves were well fitted for different conduction mechanisms. ►The electroforming and switching processes were explained.

  20. Cytotoxicity Evaluation of Anatase and Rutile TiO₂ Thin Films on CHO-K1 Cells in Vitro.

    Science.gov (United States)

    Cervantes, Blanca; López-Huerta, Francisco; Vega, Rosario; Hernández-Torres, Julián; García-González, Leandro; Salceda, Emilio; Herrera-May, Agustín L; Soto, Enrique

    2016-07-26

    Cytotoxicity of titanium dioxide (TiO₂) thin films on Chinese hamster ovary (CHO-K1) cells was evaluated after 24, 48 and 72 h of culture. The TiO₂ thin films were deposited using direct current magnetron sputtering. These films were post-deposition annealed at different temperatures (300, 500 and 800 °C) toward the anatase to rutile phase transformation. The root-mean-square (RMS) surface roughness of TiO₂ films went from 2.8 to 8.08 nm when the annealing temperature was increased from 300 to 800 °C. Field emission scanning electron microscopy (FESEM) results showed that the TiO₂ films' thickness values fell within the nanometer range (290-310 nm). Based on the results of the tetrazolium dye and trypan blue assays, we found that TiO₂ thin films showed no cytotoxicity after the aforementioned culture times at which cell viability was greater than 98%. Independently of the annealing temperature of the TiO₂ thin films, the number of CHO-K1 cells on the control substrate and on all TiO₂ thin films was greater after 48 or 72 h than it was after 24 h; the highest cell survival rate was observed in TiO₂ films annealed at 800 °C. These results indicate that TiO₂ thin films do not affect mitochondrial function and proliferation of CHO-K1 cells, and back up the use of TiO₂ thin films in biomedical science.

  1. Cytotoxicity Evaluation of Anatase and Rutile TiO2 Thin Films on CHO-K1 Cells in Vitro

    Directory of Open Access Journals (Sweden)

    Blanca Cervantes

    2016-07-01

    Full Text Available Cytotoxicity of titanium dioxide (TiO2 thin films on Chinese hamster ovary (CHO-K1 cells was evaluated after 24, 48 and 72 h of culture. The TiO2 thin films were deposited using direct current magnetron sputtering. These films were post-deposition annealed at different temperatures (300, 500 and 800 °C toward the anatase to rutile phase transformation. The root-mean-square (RMS surface roughness of TiO2 films went from 2.8 to 8.08 nm when the annealing temperature was increased from 300 to 800 °C. Field emission scanning electron microscopy (FESEM results showed that the TiO2 films’ thickness values fell within the nanometer range (290–310 nm. Based on the results of the tetrazolium dye and trypan blue assays, we found that TiO2 thin films showed no cytotoxicity after the aforementioned culture times at which cell viability was greater than 98%. Independently of the annealing temperature of the TiO2 thin films, the number of CHO-K1 cells on the control substrate and on all TiO2 thin films was greater after 48 or 72 h than it was after 24 h; the highest cell survival rate was observed in TiO2 films annealed at 800 °C. These results indicate that TiO2 thin films do not affect mitochondrial function and proliferation of CHO-K1 cells, and back up the use of TiO2 thin films in biomedical science.

  2. Cytotoxicity Evaluation of Anatase and Rutile TiO2 Thin Films on CHO-K1 Cells in Vitro

    Science.gov (United States)

    Cervantes, Blanca; López-Huerta, Francisco; Vega, Rosario; Hernández-Torres, Julián; García-González, Leandro; Salceda, Emilio; Herrera-May, Agustín L.; Soto, Enrique

    2016-01-01

    Cytotoxicity of titanium dioxide (TiO2) thin films on Chinese hamster ovary (CHO-K1) cells was evaluated after 24, 48 and 72 h of culture. The TiO2 thin films were deposited using direct current magnetron sputtering. These films were post-deposition annealed at different temperatures (300, 500 and 800 °C) toward the anatase to rutile phase transformation. The root-mean-square (RMS) surface roughness of TiO2 films went from 2.8 to 8.08 nm when the annealing temperature was increased from 300 to 800 °C. Field emission scanning electron microscopy (FESEM) results showed that the TiO2 films’ thickness values fell within the nanometer range (290–310 nm). Based on the results of the tetrazolium dye and trypan blue assays, we found that TiO2 thin films showed no cytotoxicity after the aforementioned culture times at which cell viability was greater than 98%. Independently of the annealing temperature of the TiO2 thin films, the number of CHO-K1 cells on the control substrate and on all TiO2 thin films was greater after 48 or 72 h than it was after 24 h; the highest cell survival rate was observed in TiO2 films annealed at 800 °C. These results indicate that TiO2 thin films do not affect mitochondrial function and proliferation of CHO-K1 cells, and back up the use of TiO2 thin films in biomedical science. PMID:28773740

  3. The axonal guidance cue semaphorin 3C contributes to alveolar growth and repair.

    Directory of Open Access Journals (Sweden)

    Arul Vadivel

    Full Text Available Lung diseases characterized by alveolar damage such as bronchopulmonary dysplasia (BPD in premature infants and emphysema lack efficient treatments. Understanding the mechanisms contributing to normal and impaired alveolar growth and repair may identify new therapeutic targets for these lung diseases. Axonal guidance cues are molecules that guide the outgrowth of axons. Amongst these axonal guidance cues, members of the Semaphorin family, in particular Semaphorin 3C (Sema3C, contribute to early lung branching morphogenesis. The role of Sema3C during alveolar growth and repair is unknown. We hypothesized that Sema3C promotes alveolar development and repair. In vivo Sema3C knock down using intranasal siRNA during the postnatal stage of alveolar development in rats caused significant air space enlargement reminiscent of BPD. Sema3C knock down was associated with increased TLR3 expression and lung inflammatory cells influx. In a model of O2-induced arrested alveolar growth in newborn rats mimicking BPD, air space enlargement was associated with decreased lung Sema3C mRNA expression. In vitro, Sema3C treatment preserved alveolar epithelial cell viability in hyperoxia and accelerated alveolar epithelial cell wound healing. Sema3C preserved lung microvascular endothelial cell vascular network formation in vitro under hyperoxic conditions. In vivo, Sema3C treatment of hyperoxic rats decreased lung neutrophil influx and preserved alveolar and lung vascular growth. Sema3C also preserved lung plexinA2 and Sema3C expression, alveolar epithelial cell proliferation and decreased lung apoptosis. In conclusion, the axonal guidance cue Sema3C promotes normal alveolar growth and may be worthwhile further investigating as a potential therapeutic target for lung repair.

  4. Chemical bath deposited rutile TiO{sub 2} compact layer toward efficient planar heterojunction perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chao, E-mail: lc401997413@qq.com [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Wu, Zhenhua, E-mail: 80116243@qq.com [Henan Information Engineering School, Zhengzhou 450000 (China); Li, Pengwei, E-mail: pengweili001@126.com [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Fan, Jiajie, E-mail: fanjiajie@zzu.edu.cn [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhang, Yiqiang, E-mail: yqzhang@zzu.edu.cn [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Shao, Guosheng, E-mail: gsshao@zzu.edu.cn [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China)

    2017-01-01

    Highlights: • Rutile TiO{sub 2} thin film can be grown on FTO substrate below 100 °C. • 200 mM TiCl{sub 4} precursor solution results in the best PSC performance. • UV/O{sub 3} treatment can reduce the carrier recombination effectively. • Over 12% power conversion efficiency can be achieved for PSCs. - Abstract: TiO{sub 2} is a best choice of electron transport layers in perovskite solar cells, due to its high electron mobility and stability. However, traditional TiO{sub 2} processing method requires rather high annealing temperature (>500 °C), preventing it from application to flexible devices. Here, we show that TiO{sub 2} thin films can be synthesized via chemical bath deposition below 100 °C. Typically, a compact layer of rutile TiO{sub 2} is deposited onto fluorine-doped tin oxide (FTO) coated substrates, in an aqueous TiCl{sub 4} solution at 70 °C. Through the optimization of precursor concentration and ultraviolet-ozone surface modification, over 12% power conversion efficiency can be achieved for CH{sub 3}NH{sub 3}PbI{sub 3} based perovskite solar cells. These findings offer a potential low-temperature technical solution in using TiO{sub 2} thin film as an effective transport layer for flexible perovskite solar cells.

  5. Quantum dot sensitized solar cell based on TiO2/CdS/Ag2S heterostructure

    Science.gov (United States)

    Pawar, Sachin A.; Patil, Dipali S.; Kim, Jin Hyeok; Patil, Pramod S.; Shin, Jae Cheol

    2017-04-01

    Quantum dot sensitized solar cell (QDSSC) is fabricated based on a stepwise band structure of TiO2/CdS/Ag2S to improve the photoconversion efficiency of TiO2/CdS system by incorporating a low band gap Ag2S QDs. Vertically aligned TiO2 nanorods assembly is prepared by a simple hydrothermal technique. The formation of CdS and Ag2S QDs over TiO2 nanorods assembly as a photoanode is carried out by successive ionic layer adsorption and reaction (SILAR) technique. The synthesized electrode materials are characterized by XRD, XPS, field emission scanning electron microscopy (FE-SEM), Optical, solar cell and electrochemical performances. The results designate that the QDs of CdS and Ag2S have efficiently covered exterior surfaces of TiO2 nanorods assembly. A cautious evaluation between TiO2/CdS and TiO2/CdS/Ag2S sensitized cells tells that CdS and Ag2S synergetically helps to enhance the light harvesting ability. Under AM 1.5G illumination, the photoanodes show an improved power conversion efficiency of 1.87%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 7.03 mA cm-2 which is four fold higher than that of a TiO2/CdS system.

  6. Improved conversion efficiency of dye sensitized solar cell using Zn doped TiO_2-ZrO_2 nanocomposite

    International Nuclear Information System (INIS)

    Tomar, Laxmi J.; Bhatt, Piyush J.; Desai, Rahul K.; Chakrabarty, B. S.; Panchal, C. J.

    2016-01-01

    TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites were prepared by hydrothermal method for dye sensitized solar cell (DSSC) application. The structural and optical properties were investigated by X –ray diffraction (XRD) and UV-Visible spectroscopy respectively. XRD results revealed the formation of material in nano size. The average crystallite size is 22.32 nm, 17.41 nm and 6.31 nm for TiO_2, TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites respectively. The optical bandgap varies from 2.04 eV to 3.75 eV. Dye sensitized solar cells were fabricated using the prepared material. Pomegranate juice was used as a sensitizer and graphite coated conducting glass plate was used as counter electrode. The I – V characteristics were recorded to measure photo response of DSSC. Photovoltaic parameter like open circuit voltage, power conversion efficiency, and fill factor were evaluated for fabricated solar cell. The power conversion efficiency of DSSC fabricated with TiO_2, TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites were found 0.71%, 1.97% and 4.58% respectively.

  7. Improved conversion efficiency of dye sensitized solar cell using Zn doped TiO2-ZrO2 nanocomposite

    Science.gov (United States)

    Tomar, Laxmi J.; Bhatt, Piyush J.; Desai, Rahul K.; Chakrabarty, B. S.; Panchal, C. J.

    2016-05-01

    TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites were prepared by hydrothermal method for dye sensitized solar cell (DSSC) application. The structural and optical properties were investigated by X -ray diffraction (XRD) and UV-Visible spectroscopy respectively. XRD results revealed the formation of material in nano size. The average crystallite size is 22.32 nm, 17.41 nm and 6.31 nm for TiO2, TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites respectively. The optical bandgap varies from 2.04 eV to 3.75 eV. Dye sensitized solar cells were fabricated using the prepared material. Pomegranate juice was used as a sensitizer and graphite coated conducting glass plate was used as counter electrode. The I - V characteristics were recorded to measure photo response of DSSC. Photovoltaic parameter like open circuit voltage, power conversion efficiency, and fill factor were evaluated for fabricated solar cell. The power conversion efficiency of DSSC fabricated with TiO2, TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites were found 0.71%, 1.97% and 4.58% respectively.

  8. Effects of TiO₂ and Co₃O₄ nanoparticles on circulating angiogenic cells.

    Directory of Open Access Journals (Sweden)

    Valentina Spigoni

    Full Text Available Sparse evidence suggests a possible link between exposure to airborne nanoparticles (NPs and cardiovascular (CV risk, perhaps through mechanisms involving oxidative stress and inflammation. We assessed the effects of TiO2 and Co3O4 NPs in human circulating angiogenic cells (CACs, which take part in vascular endothelium repair/replacement.CACs were isolated from healthy donors' buffy coats after culturing lymphomonocytes on fibronectin-coated dishes in endothelial medium for 7 days. CACs were pre-incubated with increasing concentration of TiO2 and Co3O4 (from 1 to 100 μg/ml to test the effects of NP – characterized by Transmission Electron Microscopy – on CAC viability, apoptosis (caspase 3/7 activation, function (fibronectin adhesion assay, oxidative stress and inflammatory cytokine gene expression.Neither oxidative stress nor cell death were associated with exposure to TiO2 NP (except at the highest concentration tested, which, however, induced a higher pro-inflammatory effect compared to Co3O4 NPs (p<0.01. Exposure to Co3O4 NPs significantly reduced cell viability (p<0.01 and increased caspase activity (p<0.01, lipid peroxidation end-products (p<0.05 and pro-inflammatory cytokine gene expression (p<0.05 or lower. Notably, CAC functional activity was impaired after exposure to both TiO2 (p<0.05 or lower and Co3O4 (p<0.01 NPs.In vitro exposure to TiO2 and Co3O4 NPs exerts detrimental effects on CAC viability and function, possibly mediated by accelerated apoptosis, increased oxidant stress (Co3O4 NPs only and enhancement of inflammatory pathways (both TiO2 and Co3O4 NPs. Such adverse effects may be relevant for a potential role of exposure to TiO2 and Co3O4 NPs in enhancing CV risk in humans.

  9. Effects of TiO2 and Co3O4 Nanoparticles on Circulating Angiogenic Cells

    Science.gov (United States)

    Spigoni, Valentina; Cito, Monia; Alinovi, Rossella; Pinelli, Silvana; Passeri, Giovanni; Zavaroni, Ivana; Goldoni, Matteo; Campanini, Marco; Aliatis, Irene; Mutti, Antonio

    2015-01-01

    Background and Aim Sparse evidence suggests a possible link between exposure to airborne nanoparticles (NPs) and cardiovascular (CV) risk, perhaps through mechanisms involving oxidative stress and inflammation. We assessed the effects of TiO2 and Co3O4 NPs in human circulating angiogenic cells (CACs), which take part in vascular endothelium repair/replacement. Methods CACs were isolated from healthy donors’ buffy coats after culturing lymphomonocytes on fibronectin-coated dishes in endothelial medium for 7 days. CACs were pre-incubated with increasing concentration of TiO2 and Co3O4 (from 1 to 100 μg/ml) to test the effects of NP – characterized by Transmission Electron Microscopy – on CAC viability, apoptosis (caspase 3/7 activation), function (fibronectin adhesion assay), oxidative stress and inflammatory cytokine gene expression. Results Neither oxidative stress nor cell death were associated with exposure to TiO2 NP (except at the highest concentration tested), which, however, induced a higher pro-inflammatory effect compared to Co3O4 NPs (p<0.01). Exposure to Co3O4 NPs significantly reduced cell viability (p<0.01) and increased caspase activity (p<0.01), lipid peroxidation end-products (p<0.05) and pro-inflammatory cytokine gene expression (p<0.05 or lower). Notably, CAC functional activity was impaired after exposure to both TiO2 (p<0.05 or lower) and Co3O4 (p<0.01) NPs. Conclusions In vitro exposure to TiO2 and Co3O4 NPs exerts detrimental effects on CAC viability and function, possibly mediated by accelerated apoptosis, increased oxidant stress (Co3O4 NPs only) and enhancement of inflammatory pathways (both TiO2 and Co3O4 NPs). Such adverse effects may be relevant for a potential role of exposure to TiO2 and Co3O4 NPs in enhancing CV risk in humans. PMID:25803285

  10. Nanometer-thin TiO2 enhances skeletal muscle cell phenotype and behavior

    Directory of Open Access Journals (Sweden)

    Ishizaki K

    2011-10-01

    Full Text Available Ken Ishizaki*, Yoshihiko Sugita*, Fuminori Iwasa, Hajime Minamikawa, Takeshi Ueno, Masahiro Yamada, Takeo Suzuki, Takahiro OgawaLaboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA*Authors contributed equally to this workBackground: The independent role of the surface chemistry of titanium in determining its biological properties is yet to be determined. Although titanium implants are often in contact with muscle tissue, the interaction of muscle cells with titanium is largely unknown. This study tested the hypotheses that the surface chemistry of clinically established microroughened titanium surfaces could be controllably varied by coating with a minimally thin layer of TiO2 (ideally pico-to-nanometer in thickness without altering the existing topographical and roughness features, and that the change in superficial chemistry of titanium is effective in improving the biological properties of titanium.Methods and results: Acid-etched microroughened titanium surfaces were coated with TiO2 using slow-rate sputter deposition of molten TiO2 nanoparticles. A TiO2 coating of 300 pm to 6.3 nm increased the surface oxygen on the titanium substrates in a controllable manner, but did not alter the existing microscale architecture and roughness of the substrates. Cells derived from rat skeletal muscles showed increased attachment, spread, adhesion strength, proliferation, gene expression, and collagen production at the initial and early stage of culture on 6.3 nm thick TiO2-coated microroughened titanium surfaces compared with uncoated titanium surfaces.Conclusion: Using an exemplary slow-rate sputter deposition technique of molten TiO2 nanoparticles, this study demonstrated that titanium substrates, even with microscale roughness, can be sufficiently chemically modified to

  11. Release of titanium ions from an implant surface and their effect on cytokine production related to alveolar bone resorption

    International Nuclear Information System (INIS)

    Wachi, Takanori; Shuto, Takahiro; Shinohara, Yoshinori; Matono, Yoshinari; Makihira, Seicho

    2015-01-01

    Although interest in peri-implant mucositis and peri-implantitis has recently been increasing, the mechanisms driving these diseases remain unknown. Here, the effects of titanium ions on the inflammation and bone resorption around an implant were investigated. First, the accumulated amount of Ti ions released into gingival and bone tissues from an implant exposed to sodium fluoride solution was measured using inductively coupled plasma mass spectrometry. Next, the cellular responses in gingival and bone tissues to Ti ions and/or Porphyromonas gingivalis-lipopolysaccharide (P. gingivalis-LPS) were assessed using a rat model. More Ti ions were detected in the gingival tissues around an implant after treatment with sodium fluoride (pH 4.2) than in its absence, which suggests that the fluoride corroded the implant surface under salivary buffering capacity. The injection of Ti ions (9 ppm) significantly increased the mRNA expression and protein accumulation of chemokine (C–C motif) ligand 2, as well as the ratio of receptor activator of nuclear factor-κB ligand to osteoprotegerin, in rat gingival tissues exposed to P. gingivalis-LPS in a synergistic manner. In addition, the enhanced localization of toll-like receptor 4, which is an LPS receptor, was observed in gingival epithelium loaded with Ti ions (9 ppm). These data suggest that Ti ions may be partly responsible for the infiltration of monocytes and osteoclast differentiation by increasing the sensitivity of gingival epithelial cells to microorganisms in the oral cavity. Therefore, Ti ions may be involved in the deteriorating effects of peri-implant mucositis, which can develop into peri-implantitis accompanied by alveolar bone resorption

  12. Proteomic Analysis of Gingival Tissue and Alveolar Bone during Alveolar Bone Healing*

    OpenAIRE

    Yang, Hee-Young; Kwon, Joseph; Kook, Min-Suk; Kang, Seong Soo; Kim, Se Eun; Sohn, Sungoh; Jung, Seunggon; Kwon, Sang-Oh; Kim, Hyung-Seok; Lee, Jae Hyuk; Lee, Tae-Hoon

    2013-01-01

    Bone tissue regeneration is orchestrated by the surrounding supporting tissues and involves the build-up of osteogenic cells, which orchestrate remodeling/healing through the expression of numerous mediators and signaling molecules. Periodontal regeneration models have proven useful for studying the interaction and communication between alveolar bone and supporting soft tissue. We applied a quantitative proteomic approach to analyze and compare proteins with altered expression in gingival sof...

  13. Heterostructured TiO2/NiTiO3 Nanorod Arrays for Inorganic Sensitized Solar Cells with Significantly Enhanced Photovoltaic Performance and Stability.

    Science.gov (United States)

    Li, Yue-Ying; Wang, Jian-Gan; Sun, Huan-Huan; Wei, Bingqing

    2018-04-11

    Organic dyes used in the conventional dye-sensitized solar cells (DSSCs) suffer from poor light stability and high cost. In this work, we demonstrate a new inorganic sensitized solar cell based on ordered one-dimensional semiconductor nanorod arrays of TiO 2 /NiTiO 3 (NTO) heterostructures prepared via a facile two-step hydrothermal approach. The semiconductor heterostructure arrays are highly desirable and promising for DSSCs because of their direct charge transport capability and slow charge recombination rate. The low-cost NTO inorganic semiconductor possesses an appropriate band gap that matches well with TiO 2 , which behaves like a "dye" to enable efficient light harvesting and fast electron-hole separation. The solar cells constructed by the ordered TiO 2 /NTO heterostructure photoanodes show a significantly improved power conversion efficiency, high fill factor, and more promising, outstanding life stability. The present work will open up an avenue to design heterostructured inorganics for high-performance solar cells.

  14. Improved conductivity in dye-sensitised solar cells through block-copolymer confined TiO 2 crystallisation

    KAUST Repository

    Guldin, Stefan; Hü ttner, Sven; Tiwana, Priti; Orilall, M. Christopher; Ü lgü t, Burak; Stefik, Morgan; Docampo, Pablo; Kolle, Matthias; Divitini, Giorgio; Ducati, Caterina; Redfern, Simon A. T.; Snaith, Henry J.; Wiesner, Ulrich; Eder, Dominik; Steiner, Ullrich

    2011-01-01

    Anatase TiO2 is typically a central component in high performance dye-sensitised solar cells (DSCs). This study demonstrates the benefits of high temperature synthesised mesoporous titania for the performance of solid-state DSCs. In contrast

  15. Parameters determining efficiency and degradation of TiO2 vertical bar dye vertical bar CuI solar cells

    International Nuclear Information System (INIS)

    Sirimanne, P.M.; Tributsch, Helmut

    2004-01-01

    The influence of the micro-morphological structure of the TiO 2 film, the distribution of CuI in TiO 2 pores and the concentration of added surfactant in the CuI coating solution on the photocurrent of solid-state TiO 2 vertical bar dye vertical bar CuI solar cells was examined by space resolved photocurrent imaging technique. Iodine is found to be competing with the oxidized dye molecules in accepting electrons from CuI and decreases the efficiency of the cell. TiO 2 vertical bar dye vertical bar CuI cell degrade two hundred times faster than wet sensitization cells. This instability is considered to be due to the decomposition of the electron transfer-bridge between the sensitizer and CuI

  16. Amplification of arsenic genotoxicity by TiO2 nanoparticles in mammalian cells: new insights from physicochemical interactions and mitochondria.

    Science.gov (United States)

    Wang, Xinan; Liu, Yun; Wang, Juan; Nie, Yaguang; Chen, Shaopeng; Hei, Tom K; Deng, Zhaoxiang; Wu, Lijun; Zhao, Guoping; Xu, An

    2017-10-01

    Titanium dioxide nanoparticles (TiO 2 NPs) have shown great adsorption capacity for arsenic (As); however, the potential impact of TiO 2 NPs on the behavior and toxic responses of As remains largely unexplored. In the present study, we focused on the physicochemical interaction between TiO 2 NPs and As(III) to clarify the underlying mechanisms involved in their synergistic genotoxic effect on mammalian cells. Our data showed that As(III) mainly interacted with TiO 2 NPs by competitively occupying the sites of hydroxyl groups on the surface of TiO 2 NP aggregates, resulting in more aggregation of TiO 2 NPs. Although TiO 2 NPs at concentrations used here had no cytotoxic or genotoxic effects on cells, they efficiently increased the genotoxicity of As(III) in human-hamster hybrid (A L ) cells. The synergistic genotoxicity of TiO 2 NPs and As(III) was partially inhibited by various endocytosis pathway inhibitors while it was completely blocked by an As(III)-specific chelator. Using a mitochondrial membrane potential fluorescence probe, a reactive oxygen species (ROS) probe together with mitochondrial DNA-depleted ρ 0 A L cells, we discovered that mitochondria were essential for mediating the synergistic DNA-damaging effects of TiO 2 NPs and As(III). These data provide novel mechanistic proof that TiO 2 NPs enhanced the genotoxicity of As(III) via physicochemical interactions, which were mediated by mitochondria-dependent ROS.

  17. Structurally stabilized mesoporous TiO2 nanofibres for efficient dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Fargol Hasani Bijarbooneh

    2013-09-01

    Full Text Available One-dimensional (1D TiO2 nanostructures are very desirable for providing fascinating properties and features, such as high electron mobility, quantum confinement effects, and high specific surface area. Herein, 1D mesoporous TiO2 nanofibres were prepared using the electrospinning method to verify their potential for use as the photoelectrode of dye-sensitized solar cells (DSSCs. The 1D mesoporous nanofibres, 300 nm in diameter and 10-20 μm in length, were aggregated from anatase nanoparticles 20-30 nm in size. The employment of these novel 1D mesoporous nanofibres significantly improved dye loading and light scattering of the DSSC photoanode, and resulted in conversion cell efficiency of 8.14%, corresponding to an ∼35% enhancement over the Degussa P25 reference photoanode.

  18. Effects of RGD immobilization on light-induced cell sheet detachment from TiO{sub 2} nanodots films

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Kui; Wang, Tiantian [School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Yu, Mengliu [The Affiliated Stomatologic Hospital, Zhejiang University, Hangzhou 310003 (China); The First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, 310003 (China); Wan, Hongping [School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Lin, Jun [The First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, 310003 (China); Weng, Wenjian, E-mail: wengwj@zju.edu.cn [School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); The Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Wang, Huiming, E-mail: hmwang1960@hotmail.com [The Affiliated Stomatologic Hospital, Zhejiang University, Hangzhou 310003 (China); The First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, 310003 (China)

    2016-06-01

    Light-induced cell detachment is reported to be a safe and effective cell sheet harvest method. In the present study, the effects of arginine–glycine–aspartic acid (RGD) immobilization on cell growth, cell sheet construction and cell harvest through light illumination are investigated. RGD was first immobilized on TiO{sub 2} nanodots films through simple physical adsorption, and then mouse pre-osteoblastic MC3T3-E1 cells were seeded on the films. It was found that RGD immobilization promoted cell adhesion and proliferation. It was also observed that cells cultured on RGD immobilized films showed relatively high level of pan-cadherin. Cells harvested with ultraviolet illumination (365 nm) showed good viability on both RGD immobilized and unmodified TiO{sub 2} nanodot films. Single cell detachment assay showed that cells detached more quickly on RGD immobilized TiO{sub 2} nanodot films. That could be ascribed to the RGD release after UV365 illumination. The current study demonstrated that RGD immobilization could effectively improve both the cellular responses and light-induced cell harvest. - Highlights: • RGD immobilization on TiO{sub 2} nanodots film favors light-induced cell sheet detachment. • Physically adsorbed RGD detaches from the film through ultraviolet illumination. • RGD detachment promotes cells and cell sheets detachment.

  19. TiO2 nanotube formation by Ti film anodization and their transport properties for dye-sensitized solar cells

    NARCIS (Netherlands)

    Iraj, M.; Kolahdouz, M.; Asl-Soleimani, E.; Esmaeili, E.; Kolahdouz Esfahani, Z.

    2016-01-01

    In this paper, we present the synthesis of TiO2 nanotube (NT) arrays formed by anodization of Ti film deposited on a fluorine-doped tin oxide-coated glass substrate by direct current magnetron sputtering. NH4F/ethylene glycol electrolyte was used to demonstrate the growth of stable nanotubes at room

  20. Tunable TiO2 Nanotube Arrays for Flexible Bio-Sensitized Solar Cells

    Science.gov (United States)

    2012-08-01

    microid extender followed by a colloidal silica /wetted imperial cloth. The foil was then cut into 1- × 2-cm samples. Then, the substrates were...17. Lei, B.; Liao, J.; Wang, R. J.; Su, C.; Kuang, D. Ordered Crystalline Ti02 Nanotube Arrays on Transparent FTO Glass for Efficient Dye...combined with a transparent , Indium Tin Dioxide coated PET film are attractive candidates for efficient, flexible DSSC’s. Flexible solar cells offer

  1. Icariin-Loaded TiO2 Nanotubes for Regulation of the Bioactivity of Bone Marrow Cells

    Directory of Open Access Journals (Sweden)

    Yanli Zhang

    2018-01-01

    Full Text Available To explore the effects of icariin on the biocompatibility of dental implants, icariin- (ICA- loaded TiO2 nanotubes were fabricated on Ti substrates via anodic oxidation and physical absorption. The surface characteristics of the specimens were monitored by field emission scanning electron microscopy (FE-SEM, X-ray diffractometry (XRD, contact angle measurements (CA, and high-pressure liquid chromatography. Additionally, the activities of bone marrow cells, such as cytoskeletal, proliferative activities, mineralization, and osteogenesis-related gene expression on the substrates were investigated in detail. The characterization results demonstrated that ICA-loaded TiO2 nanotubes were successfully fabricated and the hydrophilicity of these TiO2 nanotubes was significantly higher than that of the pure Ti groups. The results also showed that ICA-loaded TiO2 nanotubes might not have enhanced effects on cell proliferation and ALP expression. However, it seemed to significantly promote differentiation of bone marrow cells, demonstrated by enhancing the formation of mineralized nodule and the upregulation of the gene expression such as OC, BSP, OPN, and COL-1. The results indicated that ICA-loaded TiO2 nanotubes can modulate bioactivity of bone marrow cells, which is promising for potential applications in the orthopedics field.

  2. Efficiency enhancement of ZnO-based dye-sensitized solar cell by hollow TiO{sub 2} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fengrong; Wang, Guangchao; Jiao, Yu [Faculty of Materials, Optoelectronics and Physics, Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, Hunan (China); Li, Jiangyu [Department of Mechanical Engineering, University of Washington, Seattle, WA 98195-2600 (United States); Xie, Shuhong, E-mail: shxie@xtu.edu.cn [Faculty of Materials, Optoelectronics and Physics, Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, Hunan (China)

    2014-10-25

    Highlights: • The hollow TiO{sub 2} nanofibers were synthesized by one step electrospinning method. • We studied the performance of DSSC with different TiO{sub 2} weight ratioes. • The hollow TiO{sub 2} nanofibers enhance light scattering and suppress electrons recombination. • The efficiency of DSSC improved from 2.82% to 4.59% by adding 10 wt.% of TiO{sub 2}. - Abstract: One-dimensional nanostructures as the photoanode of dye-sensitized solar cell (DSSC) can provide a direct transport pathway for electrons injection to increase electrons transfer efficiency. In this work, hollow TiO{sub 2} nanofibers were fabricated by one step electrospinning based on sol–gel method, and were used to successfully enhance the conversion efficiency of ZnO-based DSSC. The effects of different TiO{sub 2} weight percentages on the performance of TiO{sub 2}/ZnO composite photoanode were investigated systematically. The results indicate that the light scattering of the photoanode film is increased and the electrons recombination is suppressed when appropriate amount of hollow TiO{sub 2} nanofibers was added into ZnO. The maximal energy conversion efficiency reaches 4.59% by adding 10 wt.% of hollow TiO{sub 2} nanofibers, which is 62% higher than that of DSSC based on pure ZnO nanoparticles.

  3. Growth of TiO2-ZrO2 Binary Oxide Electrode for Dye Sensitized Solar Cell Application

    International Nuclear Information System (INIS)

    Than Than Win; Aye Myint Myat Kywe; Shwe Yee Win; Honey Thaw; Yin Maung Maung; Ko Ko Kyaw Soe

    2011-12-01

    TiO2-ZrO2 fine binary oxide was prepared by mechanochemical milling process to be homogeneous binary oxide powder. TiO2-ZrO2 paste was deposited on microscopic glass slide by rolling. It was immersed in the henna solution and annealed at 100C for 2h. It was deposited onto another glass slide and used as counter electrode (second electrode). Two glass slides were offset and two binder clips were used to hold the electrodes together. Photovoltaic properties of TiO2-ZrO2 cell were measured and it was expected to utilize the dye sensitized solar cells application.

  4. Bactericidal Activity of TiO2 on Cells of Pseudomonas aeruginosa ATCC 27853

    Directory of Open Access Journals (Sweden)

    J. L. Aguilar Salinas

    2013-01-01

    Full Text Available The photocatalytic activity of semiconductors is increasingly being used to disinfect water, air, soils, and surfaces. Titanium dioxide (TiO2 is widely used as a photocatalyst in thin films, powder, and in mixtures with other semiconductors or metals. This work presents the antibacterial effects of TiO2 and light exposure (at 365 nm on Pseudomonas aeruginosa ATCC 27853. TiO2 powder was prepared from a mixture of titanium isopropoxide, ethanol, and nitric acid using a green and short time sol-gel technique. The obtained gel annealed at 450°C was characterized by X-ray diffraction, Raman spectroscopy, ultraviolet-visible spectroscopy, diffuse reflectance, scanning electron microscopy, and transmission electron microscopy. The nanocomposite effectively catalyzed the inactivation of Pseudomonas aeruginosa. Following 90 minutes exposure to TiO2 and UV light, logarithm of cell density was reduced from 6 to 3. These results were confirmed by a factorial design incorporating two experimental replicates and two independent factors.

  5. Preparation and characterization of dye-sensitized TiO{sub 2} nanorod solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Lijian, E-mail: ljm@isep.ipp.pt [Departamento de Física, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto (Portugal); Centro de Física, Universidade do Minho, 4800-058 Guimarães (Portugal); Chen, Hong [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, fine Mechanics and Physics of Chinese Academy of Science, Changchun 130033 (China); Li, Can [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023,China (China); Santos, M.P. dos [CEFITEC, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Departamento de Física, Escola de Ciências e Tecnologia, Universidade de Évora (Portugal)

    2015-02-27

    TiO{sub 2} nanorods were prepared by DC reactive magnetron sputtering technique and applied to dye-sensitized solar cells (DSSCs). The length of the TiO{sub 2} nanorods was varied from 1 μm to 6 μm. The scanning electron microscopy images show that the nanorods are perpendicular to the substrate. Both the X-ray diffraction patterns and Raman scattering results show that the nanorods have an anatase phase; no other phase has been observed. (101) and the (220) diffraction peaks have been observed for the TiO{sub 2} nanorods. The (101) diffraction peak intensity remained constant despite the increase of nanorod length, while the intensity of the (220) diffraction peak increased almost linearly with the nanorod length. These nanorods were used as the working electrodes in DSSCs and the effect of the nanorod length on the conversion efficiency has been studied. An optimum photoelectric conversion efficiency of 4.8% has been achieved for 4 μm length nanorods. - Highlights: • [110] oriented TiO{sub 2} nanorods were deposited on ITO substrate by dc reactive magnetron sputtering. • The structural properties of these nanorods have been studied. • The (110) texture is dominated by strain energy minimization. • DSSCs were assembled using these nanorods as electrode.

  6. Systems-level comparison of host responses induced by pandemic and seasonal influenza A H1N1 viruses in primary human type I-like alveolar epithelial cells in vitro

    Directory of Open Access Journals (Sweden)

    Guan Yi

    2010-10-01

    Full Text Available Abstract Background Pandemic influenza H1N1 (pdmH1N1 virus causes mild disease in humans but occasionally leads to severe complications and even death, especially in those who are pregnant or have underlying disease. Cytokine responses induced by pdmH1N1 viruses in vitro are comparable to other seasonal influenza viruses suggesting the cytokine dysregulation as seen in H5N1 infection is not a feature of the pdmH1N1 virus. However a comprehensive gene expression profile of pdmH1N1 in relevant primary human cells in vitro has not been reported. Type I alveolar epithelial cells are a key target cell in pdmH1N1 pneumonia. Methods We carried out a comprehensive gene expression profiling using the Affymetrix microarray platform to compare the transcriptomes of primary human alveolar type I-like alveolar epithelial cells infected with pdmH1N1 or seasonal H1N1 virus. Results Overall, we found that most of the genes that induced by the pdmH1N1 were similarly regulated in response to seasonal H1N1 infection with respect to both trend and extent of gene expression. These commonly responsive genes were largely related to the interferon (IFN response. Expression of the type III IFN IL29 was more prominent than the type I IFN IFNβ and a similar pattern of expression of both IFN genes was seen in pdmH1N1 and seasonal H1N1 infection. Genes that were significantly down-regulated in response to seasonal H1N1 but not in response to pdmH1N1 included the zinc finger proteins and small nucleolar RNAs. Gene Ontology (GO and pathway over-representation analysis suggested that these genes were associated with DNA binding and transcription/translation related functions. Conclusions Both seasonal H1N1 and pdmH1N1 trigger similar host responses including IFN-based antiviral responses and cytokine responses. Unlike the avian H5N1 virus, pdmH1N1 virus does not have an intrinsic capacity for cytokine dysregulation. The differences between pdmH1N1 and seasonal H1N1 viruses

  7. Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO{sub 2} overlay coating on TiO{sub 2} nanoparticle working electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xueyang; Fang, Jian [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia); Gao, Mei [CSIRO Materials Science and Engineering, Melbourne, VIC 3169 (Australia); Wang, Hongxia [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia); Yang, Weidong [CSIRO Materials Science and Engineering, Melbourne, VIC 3169 (Australia); Lin, Tong, E-mail: tong.lin@deakin.edu.au [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia)

    2015-02-01

    Novel TiO{sub 2} single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO{sub 2} nanorods on TiO{sub 2} nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO{sub 2} nanorods had lower dye loading than TiO{sub 2} nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO{sub 2} nanorods received less resistance than that in TiO{sub 2} nanoparticle aggregation. By just applying a thin layer of TiO{sub 2} nanorods on TiO{sub 2} nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO{sub 2} nanoparticle layer covered with 3 μm thick TiO{sub 2} nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs. - Highlights: • Single crystalline TiO{sub 2} nanorods were prepared for DSSC application. • TiO{sub 2} nanorods show effective light scattering performance. • TiO{sub 2} nanorods have higher electron transfer efficiency than TiO{sub 2} nanoparticles. • TiO{sub 2} nanorods on TiO{sub 2} nanoparticle electrode improve DSSC efficiency.

  8. Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO2 overlay coating on TiO2 nanoparticle working electrode

    International Nuclear Information System (INIS)

    Liu, Xueyang; Fang, Jian; Gao, Mei; Wang, Hongxia; Yang, Weidong; Lin, Tong

    2015-01-01

    Novel TiO 2 single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO 2 nanorods on TiO 2 nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO 2 nanorods had lower dye loading than TiO 2 nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO 2 nanorods received less resistance than that in TiO 2 nanoparticle aggregation. By just applying a thin layer of TiO 2 nanorods on TiO 2 nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO 2 nanoparticle layer covered with 3 μm thick TiO 2 nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs. - Highlights: • Single crystalline TiO 2 nanorods were prepared for DSSC application. • TiO 2 nanorods show effective light scattering performance. • TiO 2 nanorods have higher electron transfer efficiency than TiO 2 nanoparticles. • TiO 2 nanorods on TiO 2 nanoparticle electrode improve DSSC efficiency

  9. Nafion-TiO{sub 2} hybrid membranes for medium temperature polymer electrolyte fuel cells (PEFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Sacca, A.; Carbone, A.; Passalacqua, E. [CNR-ITAE, Via Salita S. Lucia Sopra Contesse, 98126 Messina (Italy); D' Epifanio, A.; Licoccia, S.; Traversa, E. [Department of Chemical Science and Technology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Sala, E.; Traini, F.; Ornelas, R. [Nuvera Fuel Cells, Via Bistolfi 35, 20134 Milan (Italy)

    2005-12-01

    A nanocomposite re-cast Nafion hybrid membrane containing titanium oxide calcined at T=400{sup o}C as an inorganic filler was developed in order to work at medium temperature in polymer electrolyte fuel cells (PEFCs) maintaining a suitable membrane hydration under fuel cell operative critical conditions. Nanometre TiO{sub 2} powder was synthesized via a sol-gel procedure by a rapid hydrolysis of Ti(OiPr){sub 4}. The membrane was prepared by mixing a Nafion-dimethylacetammide (DMAc) dispersion with a 3wt% of TiO{sub 2} powder and casting the mixture by Doctor Blade technique. The resulting film was characterised in terms of water uptake and ion exchange capacity (IEC). The membrane was tested in a single cell from 80 to 130{sup o}C in humidified H{sub 2}/air. The obtained results were compared with the commercial Nafion115 and a home-made recast Nafion membrane. Power density values of 0.514 and 0.256Wcm{sup -2} at 0.56V were obtained at 110 and 130{sup o}C, respectively, for the composite Nafion-Titania membrane. Preliminary tests carried out using steam reforming (SR) synthetic fuel at about 110{sup o}C have highlighted the benefit of the inorganic filler introduction when PEFC operates at medium temperature and with processed hydrogen. (author)

  10. Effect of TiO{sub 2} nanopatterns on the performance of hydrogenated amorphous silicon thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Joon-Ho [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Yang, Ji-Hwan; Lim, Koeng Su [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Han, Kang-Soo; Kim, Yang-Doo; Lee, Heon; Song, Jun-Hyuk [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Kyoung-Kook [Department of Nano-Optical Engineering, Korea Polytechnic University, Gyeonggi 429-793 (Korea, Republic of); Seong, Tae-Yeon, E-mail: tyseong@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2012-07-31

    We investigate how TiO{sub 2} nanopatterns formed onto ZnO:Al (AZO) films affect the performance of hydrogenated amorphous silicon (a-Si:H) solar cells. Scanning electron microscopy results show that the dome-shaped TiO{sub 2} nanopatterns (300 nm in diameter) having a period of 500 nm are formed onto AZO films and vary from 60 to 180 nm in height. Haze factor increases with an increase in the height of the nanopatterns in the wavelength region below 530 nm. Short circuit current density also increases with an increase in the height of the nanopatterns. As the nanopatterns increases in height, the fill factor of the cells slightly increases, reaches maximum (0.64) at 100 nm, and then decreases. Measurements show that a-Si:H solar cells fabricated with 100 nm-high TiO{sub 2} nanopatterns exhibit the highest conversion efficiency (6.34%) among the solar cells with the nanopatterns and flat AZO sample. - Highlights: Black-Right-Pointing-Pointer We investigated the height effect of TiO{sub 2} nanopatterns on the a-Si:H solar cells. Black-Right-Pointing-Pointer Light scattering and anti-reflection were introduced by TiO{sub 2} nanopatterns. Black-Right-Pointing-Pointer a-Si:H Solar cells with the 100 nm-high TiO{sub 2} nanopatterns showed highest efficiency.

  11. Influence of different grained powders and pellets made of Niobium and Ti-42Nb on human cell viability

    Energy Technology Data Exchange (ETDEWEB)

    Markhoff, Jana, E-mail: markhoffj@gmail.com [University Medicine Rostock, Department of Orthopedics, Biomechanics and Implant Technology Laboratory, Doberaner Strasse 142, 18057 Rostock (Germany); Weinmann, Markus [H.C. Starck Tantalum and Niobium GmbH, Im Schleeke 78-91, 38642 Goslar (Germany); Schulze, Christian; Bader, Rainer [University Medicine Rostock, Department of Orthopedics, Biomechanics and Implant Technology Laboratory, Doberaner Strasse 142, 18057 Rostock (Germany)

    2017-04-01

    Nowadays, biomaterials can be used to maintain or replace several functions of the human body if necessary. Titanium and its alloys, i.e. Ti6Al4V are the most common materials (70 to 80%) used for structural orthopedic implants due to their unique combination of good mechanical properties, corrosion resistance and biocompatibility. Addition of β-stabilizers, e.g. niobium, can improve the mechanical properties of such titanium alloys further, simultaneously offering excellent biocompatibility. In this in vitro study, human osteoblasts and fibroblasts were cultured on different niobium specimens (Nb Amperit, Nb Ampertec), Nb sheets and Ti-42Nb (sintered and 3D-printed by selective laser melting, SLM) and compared with forged Ti6Al4V specimens. Furthermore, human osteoblasts were incubated with particulates of the Nb and Ti-42Nb specimens in three concentrations over four and seven days to imitate influence of wear debris. Thereby, the specimens with the roughest surfaces, i.e. Ti-42Nb and Nb Ampertec, revealed excellent and similar results for both cell types concerning cell viability and collagen synthesis superior to forged Ti6Al4V. Examinations with particulate debris disclosed a dose-dependent influence of all powders with Nb Ampertec showing the highest decrease of cell viability and collagen synthesis. Furthermore, interleukin synthesis was only slightly increased for all powders. In summary, Nb Ampertec (sintered Nb) and Ti-42Nb materials seem to be promising alternatives for medical applications compared to common materials like forged or melted Ti6Al4V. - Highlights: • Titanium and its alloys most common materials used for structural orthopedic implants • Addition of β-stabilizers to improve mechanical properties • Roughest surfaces, Nb ampertec and Ti-42Nb, with excellent results concerning cell viability and collagen synthesis • No cell-specific differences between human osteoblasts and fibroblasts • Niobium based powders with dose- and partly

  12. TiO2 coating promotes human mesenchymal stem cell proliferation without the loss of their capacity for chondrogenic differentiation

    International Nuclear Information System (INIS)

    Kaitainen, Salla; Lappalainen, Reijo; Mähönen, Anssi J; J Lammi, Mikko; Qu, Chengjuan; Kröger, Heikki

    2013-01-01

    Human mesenchymal stem cells (hMSCs) are used in applications, which may require a large amount of cells; therefore, efficient expansion of the cells is desired. We studied whether TiO 2 coating on plastic cell culture dishes could promote proliferation of hMSCs without adverse effects in chondrogenic differentiation. TiO 2 -films were deposited on polystyrene dishes and glass coverslips using an ultrashort pulsed laser deposition technique. Human MSCs from three donors were expanded on them until 95% confluence, and the cells were evaluated by morphology, immunocytochemistry and quantitative RT-PCR (qRT-PCR). The chondrogenic differentiation in pellets was performed after cultivation on TiO 2 -coated dishes. Chondrogenesis was evaluated by histological staining of proteoglycans and type II collagen, and qRT-PCR. Human MSC-associated markers STRO-1, CD44, CD90 and CD146 did not change after expansion on TiO 2 -coated coverslips. However, the cell number after a 48h-culture period was significantly higher on TiO 2 -coated culture dishes. Importantly, TiO 2 coating caused no significant differences in the proteoglycan and type II collagen staining of the pellets, or the expression of chondrocyte-specific genes in the chondrogenesis assay. Thus, the proliferation of hMSCs could be significantly increased when cultured on TiO 2 -coated dishes without weakening their chondrogenic differentiation capacity. The transparency of TiO 2 -films allows easy monitoring of the cell growth and morphology under a phase-contrast microscope. (paper)

  13. Laser induced photocurrent and photovoltage transient measurements of dye-sensitized solar cells based on TiO_2 nanosheets and TiO_2 nanoparticles

    International Nuclear Information System (INIS)

    Ghaithan, Hamid M.; Qaid, Saif M.H.; Hezam, Mahmoud; Labis, Joselito P.; Alduraibi, Mohammad; Bedja, Idriss M.; Aldwayyan, Abdullah S.

    2016-01-01

    Dye-sensitized solar cells (DSSCs) based on TiO_2 nanoparticles and TiO_2 nanosheets with exposed {001} facets are investigated using laser-induced photovoltage and photocurrent transient decay (LIPVCD) measurements. We adopted a simplified version of LIPVCD technique, in which a single illumination light source and a laboratory oscilloscope could be conveniently used for the measurements. Although the {001} surface of TiO_2 nanosheets allowed a noticeably slower recombination with the electrolyte, this was counterpoised by a slower electron transport probably due to its planar morphology, resulting in a shorter diffusion length in TiO_2 nanosheets. The nanosheet morphology also resulted in less surface area and therefore reduced short circuit current density in the fabricated devices. Our work highlights the fact that the morphological parameters of TiO_2 nanosheets finally resulting after electrode film deposition is of no less importance than the reported efficient dye adsorption and slow electron recombination at the surface of individual nanosheets.

  14. Al2O3 doping of TiO2 electrodes and applications in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Eom, Tae Sung; Kim, Kyung Hwan; Bark, Chung Wung; Choi, Hyung Wook

    2014-01-01

    Dye-sensitized solar cells (DSSCs) have been intensively studied since their discovery in 1991. DSSCs have been extensively researched over the past decades as cheaper alternatives to silicon solar cells due to their high energy-conversion efficiency and their low production cost. However, some problems need to be solved in order to enhance the efficiency of DSSCs. In particular, the electron recombination that occurs due to the contact between the transparent conductive oxide (TCO) and a redox electrolyte is one of the main limiting factors of efficiency. In this work, we report for the first time the improvement of the photovoltaic characteristics of DSSCs by doping TiO 2 with Al 2 O 3 . DSSCs were constructed using composite particles of Al 2 O 3 -doped TiO 2 and TiO 2 nanoparticles. The DSSCs using Al 2 O 3 showed the maximum conversion efficiency of 6.29% due to effective electron transport. DSSCs based on Al 2 O 3 -doped TiO 2 films showed better photovoltaic performance than cells fabricated with only TiO 2 nanoparticles. This result is attributed to the prevention of electron recombination between electrons in the TiO 2 conduction band with holes in the dye or the electrolyte. There mechanism is suggested based on impedance results, which indicated improved electron transport at the TiO 2 /dye/electrolyte interface.

  15. Thin nanostructured crystalline TiO{sub 2} films and their applications in solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Yajun

    2007-06-15

    Research on thin nanostructured crystalline TiO{sub 2} films has attracted considerable interests because of their intriguing physical properties and potential applications in photovoltaics. Nanostructured TiO{sub 2} film plays an important role in the TiO{sub 2} based dye-sensitized solar cells because they act as a substrate for the adsorption of dye molecules and a matrix for the transportation of electrons as well. Thus they can influence the solar cell performance significantly. Consequently, the control of the morphology including the shape, size and size distribution of the TiO{sub 2} nanostructures is critical to tune and optimize the performance of the solar cells. To control the TiO{sub 2} morphology, a strategy using amphiphilic block copolymer as templating agent coupled with sol-gel chemistry has been applied. Especially, a good-poor solvent pair induced phase separation process has been developed to guide the microphase separation behavior of the block copolymers. The amphiphilic block copolymers used include polystyrene-block-poly (ethylene oxide) (PS-b-PEO), poly (methyl methacrylate)-block-poly (ethylene oxide) (PMMA-b-PEO), and poly (ethylene oxide)-block-polystyrene-block-poly (ethylene oxide) (PEO-b-PS-b-PEO). The block copolymer undergoes a good-poor-solvent pair induced phase separation in a mixed solution of 1, 4-dioxane or N, N-dimethyl formamide (DMF), concentrated hydrochloric acid (HCl) and Titanium tetraisopropoxide (TTIP). Specifically, in the system of PS-b-PEO, a morphology phase diagram of the inorganic-copolymer composite films was mapped by adjusting the weight fractions among 1, 4-dioxane, HCl, and TTIP in solution. The amorphous TiO{sub 2} within the titania-block copolymer composite films was crystallized by calcination at temperatures above 400 C, where the organic block copolymer was simultaneously burned away. This strategy is further extended to other amphiphilic block copolymers of PMMA-b-PEO and PEO-b-PS-b-PEO, where the

  16. Electrochemical properties of TiO{sub 2} encapsulated ZnO nanorod aggregates dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Justin Raj, C.; Karthick, S.N.; Dennyson Savariraj, A.; Hemalatha, K.V.; Park, Song-Ki; Kim, Hee-Je [Pusan National University, Department of Electrical Engineering, San 30, Jangjeong-Dong, Gumjeong-Ku, Busan 609 735 (Korea, Republic of); Prabakar, K., E-mail: prabakar@pusan.ac.kr [Pusan National University, Department of Electrical Engineering, San 30, Jangjeong-Dong, Gumjeong-Ku, Busan 609 735 (Korea, Republic of)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer ZnO nanorod aggregates were synthesized by simple co-precipitation technique. Black-Right-Pointing-Pointer TiO{sub 2} encapsulated ZnO nanorod aggregates photoanode was used for the DSSC. Black-Right-Pointing-Pointer TiO{sub 2} encapsulated ZnO nanorod aggregates shows an enhanced efficiency. Black-Right-Pointing-Pointer The electron recombination and transport properties were studied using EIS method. - Abstract: Dye sensitized solar cells based on TiO{sub 2} encapsulated ZnO nanorod (NR) aggregates were fabricated and electrochemical performance was analyzed using impedance spectroscopy as a function of forward bias voltage. Charge transfer properties such as electron life time ({tau}{sub n}), electron diffusion coefficient (D{sub n}) and electron diffusion length (L{sub n}) were calculated in order to ensure the influence of TiO{sub 2} layer over the ZnO NR aggregates. It is found that the short circuit current density (Jsc = 5.8 mA cm{sup -2}), open circuit potential (V{sub oc} = 0.743 V), fill factor (FF = 0.57) and conversion efficiency are significantly improved by the introduction of TiO{sub 2} layer over ZnO photoanode. A power conversion efficiency of about 2.48% has been achieved for TiO{sub 2}/ZnO cell, which is higher than that of bare ZnO NR aggregate based cells (1.73%). The formation of an inherent energy barrier between TiO{sub 2} and ZnO films and the passivation of surface traps on the ZnO film caused by the introduction of TiO{sub 2} layer increase the dye absorption and favor the electron transport which may be responsible for the enhanced performance of TiO{sub 2}/ZnO cell.

  17. Electrochemical properties of TiO2 encapsulated ZnO nanorod aggregates dye sensitized solar cells

    International Nuclear Information System (INIS)

    Justin Raj, C.; Karthick, S.N.; Dennyson Savariraj, A.; Hemalatha, K.V.; Park, Song-Ki; Kim, Hee-Je; Prabakar, K.

    2012-01-01

    Highlights: ► ZnO nanorod aggregates were synthesized by simple co-precipitation technique. ► TiO 2 encapsulated ZnO nanorod aggregates photoanode was used for the DSSC. ► TiO 2 encapsulated ZnO nanorod aggregates shows an enhanced efficiency. ► The electron recombination and transport properties were studied using EIS method. - Abstract: Dye sensitized solar cells based on TiO 2 encapsulated ZnO nanorod (NR) aggregates were fabricated and electrochemical performance was analyzed using impedance spectroscopy as a function of forward bias voltage. Charge transfer properties such as electron life time (τ n ), electron diffusion coefficient (D n ) and electron diffusion length (L n ) were calculated in order to ensure the influence of TiO 2 layer over the ZnO NR aggregates. It is found that the short circuit current density (Jsc = 5.8 mA cm −2 ), open circuit potential (V oc = 0.743 V), fill factor (FF = 0.57) and conversion efficiency are significantly improved by the introduction of TiO 2 layer over ZnO photoanode. A power conversion efficiency of about 2.48% has been achieved for TiO 2 /ZnO cell, which is higher than that of bare ZnO NR aggregate based cells (1.73%). The formation of an inherent energy barrier between TiO 2 and ZnO films and the passivation of surface traps on the ZnO film caused by the introduction of TiO 2 layer increase the dye absorption and favor the electron transport which may be responsible for the enhanced performance of TiO 2 /ZnO cell.

  18. Chemical synthesis of CdS onto TiO2 nanorods for quantum dot sensitized solar cells

    Science.gov (United States)

    Pawar, Sachin A.; Patil, Dipali S.; Lokhande, Abhishek C.; Gang, Myeng Gil; Shin, Jae Cheol; Patil, Pramod S.; Kim, Jin Hyeok

    2016-08-01

    A quantum dot sensitized solar cell (QDSSC) is fabricated using hydrothermally grown TiO2 nanorods and successive ionic layer adsorption and reaction (SILAR) deposited CdS. Surface morphology of the TiO2 films coated with different SILAR cycles of CdS is examined by Scanning Electron Microscopy which revealed aggregated CdS QDs coverage grow on increasing onto the TiO2 nanorods with respect to cycle number. Under AM 1.5G illumination, we found the TiO2/CdS QDSSC photoelectrode shows a power conversion efficiency of 1.75%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 4.04 mA/cm2 which is higher than that of a bare TiO2 nanorods array.

  19. Adsorption Equilibrium and Kinetics of Gardenia Blue on TiO2 Photoelectrode for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Tae-Young Kim

    2014-01-01

    Full Text Available Nanostructured porous TiO2 paste was deposited on the FTO conductive glass using squeeze printing technique in order to obtain a TiO2 thin film with a thickness of 10 μm and an area of 4 cm2. Gardenia blue (GB extracted from Gardenia jasminode Ellis was employed as the natural dye for a dye-sensitized solar cell (DSSC. Adsorption studies indicated that the maximum adsorption capacity of GB on the surface of TiO2 thin film was approximately 417 mg GB/g TiO2 photoelectrode. The commercial and natural dyes, N-719 and GB, respectively, were employed to measure the adsorption kinetic data, which were analyzed by pseudo-first-order and pseudo-second-order models. The energy conversion efficiency of the TiO2 electrode with successive adsorptions of GB dye was about 0.2%.

  20. In vitro biocorrosion of Ti-6Al-4V implant alloy by a mouse macrophage cell line.

    Science.gov (United States)

    Lin, Hsin-Yi; Bumgardner, Joel D

    2004-03-15

    Corrosion of implant alloys releasing metal ions has the potential to cause adverse tissue reactions and implant failure. We hypothesized that macrophage cells and their released reactive chemical species (RCS) affect the alloy's corrosion properties. A custom cell culture corrosion box was used to evaluate how cell culture medium, macrophage cells and RCS altered the Ti-6Al-4V corrosion behaviors in 72 h and how corrosion products affected the cells. There was no difference in the charge transfer in the presence (75.2 +/- 17.7 mC) and absence (62.3 +/- 18.8 mC) of cells. The alloy had the lowest charge transfer (28.2 +/- 4.1 mC) and metal ion release (Ti < 10 ppb, V < 2 ppb) with activated cells (releasing RCS) compared with the other two conditions. This was attributed to an enhancement of the surface oxides by RCS. Metal ion release was very low (Ti < 20 ppb, V < 10 ppb) with nonactivated cells and did not change cell morphology, viability, and NO and ATP release compared with controls. However, IL-1beta released from the activated cells and the proliferation of nonactivated cells were greater on the alloy than the controls. In summary, macrophage cells and RCS reduced the corrosion of Ti-6Al-4V alloys as hypothesized. These data are important in understanding host tissue-material interactions. Copyright 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 717-724, 2004

  1. Dye-sensitized solar cells based on Cr-doped TiO2 nanotube photoanodes

    Institute of Scientific and Technical Information of China (English)

    M.M.Momeni

    2017-01-01

    The effect of chromium doping on the photovoltaic efficiency of dye-sensitized solar cells (DSSCs) with anodized TiO2 nanotubes followed by an annealing process was investigated.Cr-doped TiO2 nanotubes (CrTNs) with different amounts of chromium were obtained by anodizing of titanium foils in a single-step process using potassium chromate as the chromium source.Film features were investigated by scanning electron microscopy (SEM),X-ray diffraction (XRD),energy-dispersive X-ray spectroscopy (EDX),and ultraviolet-visible (UV-Vis) spectroscopy.It is clearly seen that highly ordered TiO2 nanotubes are formed in an anodizing solution free of potassium chromate,and with a gradual increase in the potassium chromate concentration,these nanotube structures change to nanoporous and compact films without porosity.The photovoltaic efficiencies of fabricated DSSCs were characterized by a solar cell measurement system via the photocurrent-voltage (Ⅰ-Ⅴ) curves.It is found that the photovoltaic efficiency of DSSCs with CrTNsl sample is improved by more than three times compared to that of DSSCs with undoped TNs.The energy conversion efficiency increases from 1.05 % to 3.89 % by doping of chromium.

  2. Performance and electron transport properties of TiO2 nanocomposite dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Wu, J-J; Chen, G-R; Lu, C-C; Wu, W-T; Chen, J-S

    2008-01-01

    TiO 2 nanowire (NW)/nanoparticle (NP) composite films have been fabricated by hybridizing various ratios of hydrothermal anatase NWs and TiO 2 NPs for use in dye-sensitized solar cells (DSSCs). Scanning electron microscopy (SEM) images reveal that uniform NW/NP composite films were formed on fluorine-doped tin oxide (FTO) substrates by the dip-coating method. The NWs are randomly but neither vertically nor horizontally oriented within the composite film. The TiO 2 NP DSSC possesses superior performance to those of the NW/NP composite and the pure NW cells, and the efficiency of the NW/NP composite DSSC increases on increasing the NP/NW ratio in the composite anode. All types of DSSC possess the same dependence of performance on the anode thickness that the efficiency increases with the anode thickness to a maximum value, then it decreases when the anode is thickened further. Electrochemical impedance spectroscopy analyses reveal that the NP DSSCs possess larger effective electron diffusion coefficients (D eff ) in the photoanodes and smaller diffusion resistances of I 3 - in electrolytes compared to those in the NW/NP and the NW DSSCs. D eff decreases when NWs are added into the photoanode. These results suggest that the vertical feature of the NWs within the anodes is crucial for achieving a high electron transport rate in the anode

  3. Phycocyanin assemblies onto nanostructured TiO2 for photovoltaic cells

    Directory of Open Access Journals (Sweden)

    Paula Enciso

    2013-01-01

    Full Text Available The use of renewable energies is of increasing importance due to depletion of fossil fuel sources and environmental damages caused by their utilization. The energy available from the sun is clean and widely distributed. Solar cells are devices used to convert solar energy into electricity. Among them, dye sensitized solar cells are an interesting alternative to conventional silicon ones, because of their low cost and simple assembly process. They are made of a semiconductor with colored dyes adsorbed onto the surface that work as antennas to catch energy in the visible range of the spectra. In this work, nanostructured TiO2 was synthesized and the protein phycocyanin was used as dye. TiO2 was characterized by electron microscopy, X ray diffraction and infrared spectroscopy (FTIR. Phycocyanin was extracted from commercial Spirulina spp. capsules. The assembly process of the electrode covered with TiO2 and phycocyanin was controlled by cyclic voltammetry and FTIR. Results were in accordance with the assembling of an electrode sensitized with phycocyanin.

  4. Unconventional cells of TiO2 doped with erbium; Celulas nao convencionais de TiO2 dopado com erbio

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, P.C.; Campos, R.D.; Oliveira, A.S.; Wellen, R., E-mail: pollyana@cear.ufpb.edu.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Diniz, V.C.S.; Costa, A.C.F.M. da [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais

    2016-07-01

    The technology used in TiO{sub 2} solar cells is in constant improvement, new configurations have been developed, aiming practicality and leading to efficiency increase of photovoltaic devices. This paper proposes a new technology for the production of solar cells in order to investigate a better utilization of solar spectrum of TiO2 doped with erbium (Er{sup 3+}), proven by energetic conversion. The Ti{sub 0,9}Er{sub 0,1}O2 system was obtained by Pechini method. Nanoparticles have a crystallite size 65.30 nm and surface area 118.48 m{sup 2}/g. These characteristics are essential for the formation of the film to be deposited on the conductive glass substrate constituting the cell's photoelectrode. The other side of the cell is the platinum counter electrode. The cell will have the faces sealed by a thermoplastic and, finally the electrolyte will be inserted, then they will be electrically evaluated through energy efficiency and confronted with the literature data base. (author)

  5. Enhanced conversion efficiency of dye-sensitized solar cells using a CNT-incorporated TiO2 slurry-based photoanode

    OpenAIRE

    Jiaoping Cai; Zexiang Chen; Jun Li; Yan Wang; Dong Xiang; Jijun Zhang; Hai Li

    2015-01-01

    A new titanium dioxide (TiO2) slurry formulation is herein reported for the fabrication of TiO2 photoanode for use in dye-sensitized solar cells (DSSCs). The prepared TiO2 photoanode featured a highly uniform mesoporous structure with well-dispersed TiO2 nanoparticles. The energy conversion efficiency of the resulting TiO2 slurry-based DSSC was ∼63% higher than that achieved by a DSSC prepared using a commercial TiO2 slurry. Subsequently, the incorporation of acid-treated multi-walled carbon ...

  6. Obtainment of TiO2 powders solar cells photo electrodes dye sensitized

    International Nuclear Information System (INIS)

    Forbeck, Guilherme; Folgueras, Marilena V.; Chinelatto, Adilson L.

    2012-01-01

    Titanium dioxide in its polymorphic anatase phase, presents interesting properties for solar cells photo electrodes dye sensitized such as the forbidden energy band, high refractive index and high constant dielectric. In this study, powders of nanometric titanium dioxide were produced with predominantly the anatase phase and high surface area. We used the sol-gel method, and titanium tetraisopropoxide as a precursor, which was hydrolyzed in nitric acid solution. The obtained powder was heated to 450 ° C, varying the time for each lot (0, 20 or 120 minutes). The powders were characterized by X-ray diffraction, atomic force microscopy and surface area analysis. For all lots nanosized crystallites predominated. It was observed that in the batch with 120min heating an increase rutile content. The TiO 2 with 20min heating showed high surface area, greater than that of TiO 2 as taken reference

  7. Bifacial dye-sensitized solar cells based on vertically oriented TiO2 nanotube arrays

    International Nuclear Information System (INIS)

    Liu Zhaoyue; Misra, Mano

    2010-01-01

    In this work we describe a novel bifacial design concept for dye-sensitized solar cells (DSCs). Bifacial DSCs are fabricated with ruthenium complex chemisorbed double-sided TiO 2 nanotube arrays on a Ti metal substrate, in combination with two electron-collecting counter electrodes. Our investigation shows that the present bifacial DSCs have similar conversion efficiencies when illuminated from either their front or rear side, and a summated output power when illuminated on both sides. Furthermore, this type of bifacial DSC is also able to summate the output power of each side when working at an 'unsymmetrical' mode, in which much different output powers are generated by the front and rear sides. Therefore, this bifacial design concept exhibits a promising potential to reduce the cost of solar electricity when DSCs are operated at a location where a high albedo radiation is available.

  8. A Novel of Buton Asphalt and Methylene Blue as Dye-Sensitized Solar Cell using TiO2/Ti Nanotubes Electrode

    Science.gov (United States)

    Nurhidayani; Muzakkar, M. Z.; Maulidiyah; Wibowo, D.; Nurdin, M.

    2017-11-01

    A study of TiO2/Ti nanotubes arrays (NTAs) based on Dye-Sensitized Solar Cell (DSSC) used Asphalt Buton (Asbuton) extract and methylene blue (MB) as a photosensitizer dye has been conducted. The aim of this research is that the Asbuton extract and Methylene Blue (MB) performance as a dye on DSSC solar cells is able to obtain the voltage-currents produced by visible light irradiation. Electrode TiO2/Ti NTAs have been successfully synthesized by anodizing methods, then characterized by using XRD showed that the anatase crystals formed. Subsequently, the morphology showed that the nanotubes formed which has coated by Asbuton extract. The DSSC system was formed by a sandwich structure and tested by using Multimeter Digital with Potentiostat instrument. The characteristics of current (I) and potential (V) versus time indicated that the Asbuton was obtained in a high-performance in 30s of 14,000µV 0.844µA, meanwhile MB dyes were 8,000µV0.573µA. Based on this research, the Asbuton extract from Buton Island-Southeast Sulawesi-Indonesia was potential for natural dyes in DSSC system.

  9. Nanostructured TiOx as a catalyst support material for proton exchange membrane fuel cells

    Science.gov (United States)

    Phillips, Richard S.

    Recent interest in the development of new catalyst support materials for proton exchange membrane fuel cells (PEMFCs) has stimulated research into the viability of TiO2-based support structures. Specifically, substoichiometric TiO2 (TiOx) has been reported to exhibit a combination of high conductivity, stability, and corrosion resistance. These properties make TiOx-based support materials a promising prospect when considering the inferior corrosion resistance of traditional carbon-based supports. This document presents an investigation into the formation of conductive and stable TiOx thin films employing atomic layer deposition (ALD) and a post deposition oxygen reducing anneal (PDORA). Techniques for manufacturing TiOx-based catalyst support nanostructures by means of ALD in conjunction with carbon black (CB), anodic aluminum oxide (AAO) and silicon nanowires (SiNWs) will also be presented. The composition and thickness of resulting TiOx thin films was determined with the aid of Auger electron spectroscopy (AES), Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). Film crystal structure was determined with X-ray diffraction (XRD) analysis. Film conductivity was calculated using four-point probe (4-PP) and film thickness measurement data. Resulting thin films show a significant decrease of oxygen in ALD TiOx films corresponding with a great increase in conductivity following the PDORA. The effectiveness of the PDORA was also found to be highly dependent on ALD process parameters. TiOx-based nanostructures were coated with platinum using one of three Pt deposition techniques. First, liquid phase deposition (LPD), which was performed at room temperature, provided equal access to catalyst support material surfaces which were suspended in solution. Second, plasma enhanced atomic layer deposition (PEALD), which was performed at 450°C, provided good Pt

  10. Differential effect of aqueous Desmodium gangeticum root extract mediated TiO2 nanoparticles on isolated mitochondria, cells and Wistar rats

    Directory of Open Access Journals (Sweden)

    Mahalakshmi Ansari

    2017-11-01

    Conclusions: The biochemical findings in renal tissue and epithelial cell (LLC-PK1 supported by histopathology examination and isolated mitochondrial activity showed minor toxicity with TiNPs prepared by green route (TiNP DG than TiNP Chem.

  11. Enhanced performance of inverted organic photovoltaic cells using CNTs-TiO(X) nanocomposites as electron injection layer.

    Science.gov (United States)

    Zhang, Hong; Xu, Meifeng; Cui, Rongli; Guo, Xihong; Yang, Shangyuan; Liao, Liangsheng; Jia, Quanjie; Chen, Yu; Dong, Jinquan; Sun, Baoyun

    2013-09-06

    In this study, we fabricated inverted organic photovoltaic cells with the structure ITO/carbon nanotubes (CNTs)-TiO(X)/P3HT:PCBM/MoO₃/Al by spin casting CNTs-TiO(X) nanocomposite (CNTs-TiO(X)) as the electron injection layer onto ITO/glass substrates. The power conversion efficiency (PCE) of the 0.1 wt% single-walled nanotubes (SWNTs)-TiO(X) nanocomposite device was almost doubled compared with the TiO(X) device, but with increasing concentration of the incorporated SWNTs in the TiO(X) film, the performance of the devices appeared to decrease rapidly. Devices with multi-walled NTs in the TiO(X) film have a similar trend. This phenomenon mainly depends on the inherent physical and chemical characteristics of CNTs such as their high surface area, their electron-accepting properties and their excellent carrier mobility. However, with increasing concentration of CNTs, CNTs-TiO(X) current leakage pathways emerged and also a recombination of charges at the interfaces. In addition, there was a significant discovery. The incorporated CNTs were highly conducive to enhancing the degree of crystallinity and the ordered arrangement of the P3HT in the active layers, due to the intermolecular π-π stacking interactions between CNTs and P3HT.

  12. Comparative analysis of Dye-Sensitized Solar Cells (DSSC) having different nanocrystalline TiO2 layer structures

    International Nuclear Information System (INIS)

    Forcade, Fresnel; Gonzalez, Bernardo; Vigil, Elena; Jennings, James R.; Duna, Halina; Wang, Hongxia; Peter, Laurence M.

    2009-01-01

    Full text: Dye-sensitized solar cells (DSSC) are very prospective because of their low cost and comparatively not so low efficiency. This represents an advantage together with the innocuous character of the constituent materials. We study different types of DSSC. The procedure for making them has been the same except for the TiO 2 layer structure. This layer must be porous and nanocrystalline in order to increase light absorption by the sensitizer. On the other hand, this condition causes that the electrolyte contacts the transparent conducting oxide (TCO) underneath the TiO 2 originating undesired recombinations. Also the electrical contact of the Tio to the TCO depends on the technology used to deposit the TiO 2 . In order to avoid possible leakage currents caused by recombinations from the TCO to the electrolyte and improve TiO 2 -TCO electrical contact, a thin TiO 2 film is placed in between the porous TiO 2 layer and the TCO. Different structures are obtained using different technologies to obtain the thin TiO 2 film. These structures are analyzed from their volt-amperic characteristic, external quantum efficiency spectra and voltage decay observed when light is suppressed. Results obtained allow making recommendations regarding nanocrystalline TiO 2 structure to be used in DSSC. (author)

  13. Theoretical Study of Ultrafast Electron Injection into a Dye/TiO2 System in Dye-Sensitized Solar Cells

    Science.gov (United States)

    Lin, Chundan; Xia, Qide; Li, Kuan; Li, Juan; Yang, Zhenqing

    2018-06-01

    The ultrafast injection of excited electrons in dye/TiO2 system plays a critical role, which determines the device's efficiency in large part. In this work, we studied the geometrical structures and electronic properties of a dye/TiO2 composite system for dye-sensitized solar cells (DSSCs) by using density functional theory, and we analyzed the mechanism of ultrafast electron injection with emphasis on the power conversion efficiency. The results show that the dye SPL103/TiO2 (101) surface is more stable than dye SPL101. The electron injection driving force of SPL103/TiO2 (101) is 3.55 times that of SPL101, indicating that SPL103/TiO2 (101) has a strong ability to transfer electrons. SPL103 and SPL101/TiO2 (101) both have fast electron transfer processes, and especially the electron injection time of SPL103/TiO2 (101) is only 1.875 fs. The results of this work are expected to provide a new understanding of the mechanism of electron injection in dyes/TiO2 systems for use in highly effective DSSCs.

  14. In situ modification of cell-culture scaffolds by photocatalysis of visible-light-responsive TiO2 film

    Science.gov (United States)

    Kono, Sho; Furusawa, Kohei; Kurotobi, Atsushi; Hattori, Kohei; Yamamoto, Hideaki; Hirano-Iwata, Ayumi; Tanii, Takashi

    2018-02-01

    We propose a novel process to modify the cell affinity of scaffolds in a cell-culture environment using the photocatalytic activity of visible-light (VL)-responsive TiO2. The proposed process is the improved version of our previous demonstration in which ultraviolet (UV)-responsive TiO2 was utilized. In that demonstration, we showed that cell-repellent molecules on TiO2 were decomposed and replaced with cell-permissive molecules upon UV exposure in the medium where cells are being cultured. However, UV irradiation involves taking the risk of inducing damage to the cells. In this work, a TiO2 film was sputter-deposited on a quartz coverslip at 640 °C without O2 gas injection to create a rutile structure containing oxygen defects, which is known to exhibit photocatalytic activity upon VL exposure. We show that the cell adhesion site and migration area can be controlled with the photocatalytic activity of the VL-responsive TiO2 film, while the cellular oxidative stress is reduced markedly by the substitution of VL for UV.

  15. Influence of different TiO2 blocking films on the photovoltaic performance of perovskite solar cells

    Science.gov (United States)

    Zhang, Chenxi; Luo, Yudan; Chen, Xiaohong; Ou-Yang, Wei; Chen, Yiwei; Sun, Zhuo; Huang, Sumei

    2016-12-01

    Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic (PV) cells. Cell structures based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive and brisk advances, holding great potential to grow into a mature PV technology. High power conversion efficiency (PCE) values have been obtained from the mesoscopic configuration in which a few hundred nano-meter thick mesoporous scaffold (e.g. TiO2 or Al2O3) infiltrated by perovskite absorber was sandwiched between the electron and hole transport layers. A uniform and compact hole-blocking layer is necessary for high efficient perovskite-based thin film solar cells. In this study, we investigated the characteristics of TiO2 compact layer using various methods and its effects on the PV performance of perovskite solar cells. TiO2 compact layer was prepared by a sol-gel method based on titanium isopropoxide and HCl, spin-coating of titanium diisopropoxide bis (acetylacetonate), screen-printing of Dyesol's bocking layer titania paste, and a chemical bath deposition (CBD) technique via hydrolysis of TiCl4, respectively. The morphological and micro-structural properties of the formed compact TiO2 layers were characterized by scanning electronic microscopy and X-ray diffraction. The analyses of devices performance characteristics showed that surface morphologies of TiO2 compact films played a critical role in affecting the efficiencies. The nanocrystalline TiO2 film deposited via the CBD route acts as the most efficient hole-blocking layer and achieves the best performance in perovskite solar cells. The CBD-based TiO2 compact and dense layer offers a small series resistance and a large recombination resistance inside the device, and makes it possible to achieve a high power conversion efficiency of 12.80%.

  16. Hydrothermal synthesis, characterization, photocatalytic activity and dye-sensitized solar cell performance of mesoporous anatase TiO2 nanopowders

    International Nuclear Information System (INIS)

    Pavasupree, Sorapong; Jitputti, Jaturong; Ngamsinlapasathian, Supachai; Yoshikawa, Susumu

    2008-01-01

    Mesoporous anatase TiO 2 nanopowder was synthesized by hydrothermal method at 130 deg. C for 12 h. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), HRTEM, and Brunauer-Emmett-Teller (BET) surface area. The as-synthesized sample with narrow pore size distribution had average pore diameter about 3-4 nm. The specific BET surface area of the as-synthesized sample was about 193 m 2 /g. Mesoporous anatase TiO 2 nanopowders (prepared by this study) showed higher photocatalytic activity than the nanorods TiO 2 , nanofibers TiO 2 mesoporous TiO 2 , and commercial TiO 2 nanoparticles (P-25, JRC-01, and JRC-03). The solar energy conversion efficiency (η) of the cell using the mesoporous anatase TiO 2 was about 6.30% with the short-circuit current density (Jsc) of 13.28 mA/cm 2 , the open-circuit voltage (Voc) of 0.702 V and the fill factor (ff) of 0.676; while η of the cell using P-25 reached 5.82% with Jsc of 12.74 mA/cm 2 , Voc of 0.704 V and ff of 0.649

  17. Multifunctional graded index TiO{sub 2} compact layer for performance enhancement in dye sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, M.H., E-mail: abuhanifahabllh@yahoo.com [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Rusop, M. [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia)

    2013-11-01

    A specially tailored index TiO{sub 2} compact layer (arc-TiO{sub 2}) has been successfully deposited to serve as photoanode of a dye-sensitized solar cell (DSSC) by radio-frequency magnetron sputtering. The employment of the TiO{sub 2} compact layer in the DSSC was systematically investigated by means of UV-absorption spectra, incident photon to current efficiency (IPCE), open-circuit voltage decay (OCVD) and electrochemical impedance spectroscopy (EIS). The higher and red-shifted transmittance spectra of the ITO/arc-TiO{sub 2} electrode mimic the IPCE spectra of the DSSC, in a specific wavelength region. Furthermore, the blue-shift of the UV-absorption spectra and lower R{sub 1} value obtained from EIS measurements implied the decrease of the charge interfacial resistance, and this consequently facilitates the charge transport from the nanocrystalline-TiO{sub 2} to the ITO. The integrated effects of the arc-TiO{sub 2} compact layer originate the remarkable improvement in this type of DSSC applications. As a result, the arc-TiO{sub 2}-based DSSC showed higher conversion efficiency of about 4.38%, representing almost 53% increment compared to bare ITO cell. This work also discuss the fundamental insight of the compact layer that determines the origin of such improvement in the DSSC performance.

  18. Influence of sterilization methods on cell behavior and functionality of osteoblasts cultured on TiO2 nanotubes

    International Nuclear Information System (INIS)

    Oh, Seunghan; Brammer, Karla S.; Moon, Kyung-Suk; Bae, Ji-Myung; Jin, Sungho

    2011-01-01

    We investigated the adhesion, proliferation and osteogenic functionality of osteoblasts cultured on titanium dioxide (TiO 2 ) nanotubes in response to different sterilization methods (dry autoclaving vs. wet autoclaving). We prepared various sizes (30-100 nm diameter) of TiO 2 nanotubes on titanium substrates by anodization, sterilized nanotubes by different conditions, and seeded osteoblast cells onto the nanotube surfaces with two different cell seeding densities (10,000 vs. 50,000 cells/well in 12-culture well). The result of this study indicates that the adhesion, proliferation and alkaline phosphatase activity of osteoblasts cultured on only the larger 70 and 100 nm TiO 2 nanotube arrays were dramatically changed by the different sterilization conditions at a low cell seeding density. However, with a higher cell seeding density (50,000 cells/well in 12-cell culture well), the results revealed no significant difference among altered nanotube geometry, 30-100 nm diameters, nor sterilization methods. Next, it was revealed that the nanofeatures of proteins adhered on nanotubular TiO 2 morphology are altered by the sterilization method. It was determined that this protein adhesion effect, in combination with the cell density of osteoblasts seeded onto such TiO 2 nanotube surfaces, has profound effects on cell behavior. This study clearly shows that these are some of the important in vitro culture factors that need to be taken into consideration, as well as TiO 2 nanotube diameters which play an important role in the improvement of cell behavior and functionality.

  19. Biological Behavior of Osteoblast Cell and Apatite Forming Ability of the Surface Modified Ti Alloys.

    Science.gov (United States)

    Zhao, Jingming; Hwang, K H; Choi, W S; Shin, S J; Lee, J K

    2016-02-01

    Titanium as one kind of biomaterials comes in direct contact with the body, making evaluation of biocompatibility an important aspect to biomaterials development. Surface chemistry of titanium plays an important role in osseointegration. Different surface modification alters the surface chemistry and result in different biological response. In this study, three kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coating successfully formed on the Ti surfaces in simulated body fluid. Strong mixed acid increased the roughness of the metal surface, because the porous and rough surface allows better adhesion between Ca-P coatings and substrates. After modification of titanium surface by mixed acidic solution and subsequently H2O2/HCL treatment evaluation of biocompatibility was conducted from hydroxyapatite formation by biomimetic process and cell viability on modified titanium surface. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Results from this study indicated that surface treatment methods affect the surface morphology, type of TiO2 layer formed and subsequent apatite deposition and biological responses. The thermo scientific alamarblue cell viability assay reagent is used to quantitatively measure the viability of mammalian cell lines, bacteria and fungi by incorporating a rapid, sensitive and reliable fluorometric/colorimetric growth indicator, without any toxic and side effect to cell line. In addition, mixed acid treatment uses a lower temperature and shorter time period than widely used alkali treatment.

  20. Mesoscopic CH 3 NH 3 PbI 3 /TiO 2 Heterojunction Solar Cells

    KAUST Repository

    Etgar, Lioz

    2012-10-24

    We report for the first time on a hole conductor-free mesoscopic methylammonium lead iodide (CH 3NH 3PbI 3) perovskite/TiO 2 heterojunction solar cell, produced by deposition of perovskite nanoparticles from a solution of CH 3NH 3I and PbI 2 in γ-butyrolactone on a 400 nm thick film of TiO 2 (anatase) nanosheets exposing (001) facets. A gold film was evaporated on top of the CH 3NH 3PbI 3 as a back contact. Importantly, the CH 3NH 3PbI 3 nanoparticles assume here simultaneously the roles of both light harvester and hole conductor, rendering superfluous the use of an additional hole transporting material. The simple mesoscopic CH 3NH 3PbI 3/TiO 2 heterojunction solar cell shows impressive photovoltaic performance, with short-circuit photocurrent J sc= 16.1 mA/cm 2, open-circuit photovoltage V oc = 0.631 V, and a fill factor FF = 0.57, corresponding to a light to electric power conversion efficiency (PCE) of 5.5% under standard AM 1.5 solar light of 1000 W/m 2 intensity. At a lower light intensity of 100W/m 2, a PCE of 7.3% was measured. The advent of such simple solution-processed mesoscopic heterojunction solar cells paves the way to realize low-cost, high-efficiency solar cells. © 2012 American Chemical Society.

  1. The Alveolar Microenvironment of Patients Infected with Human Immunodeficiency Virus Does Not Modify Alveolar Macrophage Interactions with Streptococcus pneumoniae

    Science.gov (United States)

    Jagoe, R. Thomas; Jarman, Elizabeth R.; North, James C.; Pridmore, Alison; Musaya, Janelisa; French, Neil; Zijlstra, Eduard E.; Molyneux, Malcolm E.; Read, Robert C.

    2013-01-01

    We tested the hypothesis that HIV infection results in activation of alveolar macrophages and that this might be associated with impaired defense against pneumococcus. We compared alveolar macrophages and lymphocytes in 131 bronchoalveolar lavage samples from HIV-infected and healthy controls using inflammatory gene microarrays, flow cytometry, real-time PCR, and enzyme-linked immunosorbent assay (ELISA) to determine the pattern of macrophage activation associated with HIV infection and the effect of this activation on defense against pneumococcus. We used gamma interferon (IFN-γ) priming to mimic the cellular milieu in HIV-infected lungs. InnateDB and BioLayout 3D were used to analyze the interactions of the upregulated genes. Alveolar macrophages from HIV-infected adults showed increased gene expression and cytokine production in a classical pattern. Bronchoalveolar lavage from HIV-infected subjects showed excess CD8+ lymphocytes with activated phenotype. Toll-like receptor 4 (TLR4) expression was increased in macrophages from HIV-infected subjects, but function was similar between the groups; lung lavage fluid did not inhibit TLR function in transfected HeLa cells. Alveolar macrophages from HIV-infected subjects showed normal binding and internalization of opsonized pneumococci, with or without IFN-γ priming. Alveolar macrophages from HIV-infected subjects showed classical activation compared to that of healthy controls, but this does not alter macrophage interactions with pneumococci. PMID:23576675

  2. True Fibroma of Alveolar Mucosa

    Directory of Open Access Journals (Sweden)

    Shankargouda Patil

    2014-01-01

    Full Text Available Benign fibrous overgrowths are often found in the oral cavity, almost always being reactive/irritational in nature. However, benign mesenchymal neoplasms of the fibroblasts are extremely uncommon. Here we report a case of “True Fibroma of Alveolar Mucosa” for its rarity.

  3. Intravascular bronchio-alveolar tumor

    International Nuclear Information System (INIS)

    Mata, J.M.; Caceres, J.; Prat, J.; Lopez, J.I.; Velilla, O.

    1991-01-01

    In 1975 Dail and Liebow described the clinical and pathological characteristics of a pulmonary tumor which they dominated intravascular bronchio-alveolar tumor (IVBAT). Our aim is to acquaint radiologists with the existence of this tumor by describing the radiologic findings in 2 patients with IVBAT, 1 with hepatic involvement ant the other with pulmonary osteoarthropathy. (author). 7 refs.; 2 figs

  4. SaOS-2 cell response to macro-porous boron-incorporated TiO{sub 2} coating prepared by micro-arc oxidation on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qianli [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Elkhooly, Tarek A. [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Department of Ceramics, Inorganic Chemical Industries Division, National Research Centre, Dokki, 12622 Cairo (Egypt); Liu, Xujie [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Zhang, Ranran; Yang, Xing; Shen, Zhijian [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Feng, Qingling, E-mail: biomater@mail.tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2016-10-01

    The aims of the present study were to develop boron-incorporated TiO{sub 2} coating (B-TiO{sub 2} coating) through micro-arc oxidation (MAO) and subsequently evaluate the effect of boron incorporation on the in vitro biological performance of the coatings. The physicochemical properties of B-TiO{sub 2} coating and its response to osteoblast like cells (SaOS-2) were investigated compared to the control group without boron (TiO{sub 2} coating). The morphological and X-ray diffraction results showed that both coatings exhibited similar surface topography and phase composition, respectively. However, the incorporation of B led to an enhancement in the surface hydrophilicity of B-TiO{sub 2} coating. The spreading of SaOS-2 cells on B-TiO{sub 2} coating was faster than that on TiO{sub 2} coating. The proliferation rate of SaOS-2 cells cultured on B-TiO{sub 2} decreased after 5 days of culture compared to that on TiO{sub 2} coating. SaOS-2 cells cultured on B-TiO{sub 2} coating exhibited an enhanced alkaline phosphatase (ALP) activity, Collagen I synthesis and in vitro mineralization compared to those on TiO{sub 2} coating. The present findings suggest that B-TiO{sub 2} coating is a promising candidate surface for orthopedic implants. - Highlights: • SaOS-2 cell response to pure TiO{sub 2} and B-TiO{sub 2} coatings was investigated. • Initial cell spreading on B-TiO{sub 2} coating was accelerated compared to that on TiO{sub 2} coating. • Cell proliferation on B-TiO{sub 2} coating was inhibited compared to that on TiO{sub 2} coating. • Cell differentiation on B-TiO{sub 2} coating was enhanced compared to that on TiO{sub 2} coating.

  5. Hybrid Solar Cell with TiO2 Film: BBOT Polymer and Copper Phthalocyanine as Sensitizer

    Directory of Open Access Journals (Sweden)

    Saptadip Saha

    2016-01-01

    Full Text Available An organic-inorganic hybrid solar cell was fabricated using Titanium dioxide (TiO2: 2,5-bis(5-tert-butyl-2-benzoxazolyl thiophene (BBOT film and Copper Phthalocyanine (CuPc as a sensitizer. BBOT was used in photodetector in other reported research works, but as per best of our knowledge, it was not implemented in solar cells till date. The blend of TiO2: BBOT blend was used to fabricate the film on ITO-coated glass and further a thin layer of CuPc was coated on the film. This was acted as photoanode and another ITO coated glass with a platinum coating was used as a counter electrode (cathode. An optimal blend of acetonitrile (solvent (50-100%, 1,3-dimethylimidazolium iodide (10-25%, iodine (2.5-10% and lithium iodide, pyridine derivative and thiocyanate was used as electrolytes in the hybrid solar cell. The different structural, optical and electrical characteristics were measured. The Hybrid solar cell showed a maximum conversion efficiency of 6.51%.

  6. TiO2 Nanowire Networks Prepared by Titanium Corrosion and Their Application to Bendable Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Saera Jin

    2017-10-01

    Full Text Available TiO2 nanowire networks were prepared, using the corrosion of Ti foils in alkaline (potassium hydroxide, KOH solution at different temperatures, and then a further ion-exchange process. The prepared nanostructures were characterized by field emission scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The wet corroded foils were utilized as the photoanodes of bendable dye-sensitized solar cells (DSSCs, which exhibited a power conversion efficiency of 1.11% under back illumination.

  7. TiO₂ Nanowire Networks Prepared by Titanium Corrosion and Their Application to Bendable Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Jin, Saera; Shin, Eunhye; Hong, Jongin

    2017-10-12

    TiO₂ nanowire networks were prepared, using the corrosion of Ti foils in alkaline (potassium hydroxide, KOH) solution at different temperatures, and then a further ion-exchange process. The prepared nanostructures were characterized by field emission scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The wet corroded foils were utilized as the photoanodes of bendable dye-sensitized solar cells (DSSCs), which exhibited a power conversion efficiency of 1.11% under back illumination.

  8. Preparation of sol-gel TiO2/purified Na-bentonite composites and their photovoltaic application for natural dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Saelim, Ni-on; Magaraphan, Rathanawan; Sreethawong, Thammanoon

    2011-01-01

    Highlights: → Natural dye from red cabbage was successfully employed in DSSC. → A fast sol-gel method to produce TiO 2 /clay thin film was proposed. → The sol-gel-prepared TiO 2 /clay was applied as the scattering layer on top of TiO 2 electrode. → Thicker sol-gel-prepared TiO 2 /clay electrode showed higher DSSC efficiency. - Abstract: The sol-gel TiO 2 /purified natural clay electrodes having Ti:Si molar ratios of 95:5 and 90:10 were initially prepared, sensitized with natural red cabbage dye, and compared to the sol-gel TiO 2 electrode in terms of physicochemical characteristics and solar cell efficiency. The results showed that the increase in purified Na-bentonite content greatly increased the specific surface area and total pore volume of the prepared sol-gel TiO 2 /purified Na-bentonite composites because the clay platelets prevented TiO 2 particle agglomeration. The sol-gel TiO 2 /5 mol% Si purified Na-bentonite and sol-gel TiO 2 /10 mol% Si purified Na-bentonite composites could increase the film thickness of solar cells without cracking when they were coated as a scattering layer on the TiO 2 semiconductor-based film, leading to increasing the efficiency of the natural dye-sensitized solar cells in this work.

  9. Electrical Properties of Al, Ag, Cu, Ti and SS Thin Film for Electrode of Solar Cell

    International Nuclear Information System (INIS)

    Bambang Siswanto; Wirjoadi; Sudjatmoko; Tjipto Sujitno

    2003-01-01

    The Al, Ag, Cu, Ti and SS materials were deposited on the surface of glass substrate using plasma DC sputtering technique. The deposition process was done with the following plasma parameters : deposition time, gas pressure and substrate temperature with the aim to obtain a good conductance of thin films. Variation of substrate deposition time was 1 - 15 minutes, gas pressure was 5x10 -2 - 7x10 -2 torr and of temperature was 100 - 300 o C. The resistance measurement has been done by four points probes and the conductivity was calculated using mathematic formulation. It was obtained that the minimum resistance in the order of R = 0.07 Ω, was found at Ag materials and this was obtained at the following plasma parameters : deposition time 15 minutes, gas pressure 6x10 -2 torr and temperature 300 o C, while, the resistance of : Cu, Al, Ti and SS materials were R = 0.13 Ω, R = 450 Ω, R = 633 Ω, R = 911 Ω respectively, It could be concluded that the Ag thin film has a minimum resistance, high conductivity compared to the other materials Al, Cu, Ti and SS. Ag is therefore the suitable material for applying as electrode of solar cell. (author)

  10. M(Al,Ni)-TiO2-Based Photoanode for Photoelectrochemical Solar Cells

    Science.gov (United States)

    Navas, Javier; Reyes-Pérez, Fran; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Bernal, Juan Jesús Gallardo; Martín-Calleja, Joaquín

    2018-05-01

    This study presents the incorporation of Al and Ni cations onto the surface of TiO2 nanoparticles used as photoelectrode in dye sensitized solar cells (DSSCs). The incorporation of these cations was performed using the chemical bath deposition (CBD) technique. This process was applied up to three times to evaluate the semiconductors' properties with respect to the amount of Al and Ni. The M(Al,Ni)-TiO2-based semiconductors were widely characterized using techniques such as X-ray fluorescence, X-ray diffraction, Raman spectroscopy, UV-Vis spectroscopy and X-ray photoelectron spectroscopy. The presence of (hydr)oxide species of Al(III) and Ni(II) was confirmed and anatase was the predominant crystalline phase obtained. Moreover, for both elements, a decrease in the band gap energy was observed, this being more pronounced after the incorporation of Ni. Furthermore, the use of the M(Al,Ni)-TiO2-based semiconductors as photoelectrodes in DSSCs led to an increase in the open-circuit voltage of up to 22% and 10% for the incorporation of Al and Ni, respectively. This increase can be reasonably explained by the negative shift of the flat band potential of the photoelectrodes. EIS measurements were performed to study the electron transport kinetics in the photoelectrode and the internal resistance in the DSSCs to understand the photocurrent density values obtained.

  11. Dispersions of geometric TiO2 nanomaterials and their toxicity to RPMI 2650 nasal epithelial cells

    Science.gov (United States)

    Tilly, Trevor B.; Kerr, Lei L.; Braydich-Stolle, Laura K.; Schlager, John J.; Hussain, Saber M.

    2014-11-01

    Titanium dioxide (TiO2) based nanofilaments—nanotube, nanowire, nanorod—have gained interest for industrial, electrical, and as of recent, medical applications due to their superior performance over TiO2 nanoparticles. Safety assessment of these nanomaterials is critical to protect workers, patients, and bystanders as these technologies become widely implemented. Additionally, TiO2 based nanofilaments can easily be inhaled by humans and their high aspect ratio, much like asbestos fibers, may make them toxic in the respiratory system. The tendency of TiO2 nanofilaments to aggregate makes evaluating their nanotoxicity difficult and the results controversial, because incomplete dispersion results in larger particle sizes that are no longer in the nano dimensional size range. TiO2 nanofilaments are aggregated and difficult to disperse homogeneously in solution by conventional methods, such as sonication and vortexing. In this study, a microfluidic device was utilized to produce stable, homogeneous dosing solutions necessary for in vitro toxicity evaluation by eliminating any toxicity caused by aggregated TiO2 nanomaterials. The toxicity results could then be directly correlated to the TiO2 nanostructure itself. The toxicity of four TiO2 nanogeometries—nanotube, nanowire, nanorod, and nanoparticle—were assessed in RPMI 2650 human nasal epithelial cells at representative day, week, and month in vitro exposure dosages of 10, 50, 100 μg/ml, respectively. All TiO2 based nanomaterials dispersed by the microfluidic method were nontoxic to RPMI 2650 cells at the concentrations tested, whereas higher concentrations of 100 μg/ml of nanowires and nanotubes dispersed by sonication reduced viability up to 27 %, indicating that in vitro toxicity results may be controlled by the dispersion of dosing solutions.

  12. DA-Raf-Mediated Suppression of the Ras--ERK Pathway Is Essential for TGF-β1-Induced Epithelial-Mesenchymal Transition in Alveolar Epithelial Type 2 Cells.

    Science.gov (United States)

    Watanabe-Takano, Haruko; Takano, Kazunori; Hatano, Masahiko; Tokuhisa, Takeshi; Endo, Takeshi

    2015-01-01

    Myofibroblasts play critical roles in the development of idiopathic pulmonary fibrosis by depositing components of extracellular matrix. One source of lung myofibroblasts is thought to be alveolar epithelial type 2 cells that undergo epithelial-mesenchymal transition (EMT). Rat RLE-6TN alveolar epithelial type 2 cells treated with transforming growth factor-β1 (TGF-β1) are converted into myofibroblasts through EMT. TGF-β induces both canonical Smad signaling and non-canonical signaling, including the Ras-induced ERK pathway (Raf-MEK-ERK). However, the signaling mechanisms regulating TGF-β1-induced EMT are not fully understood. Here, we show that the Ras-ERK pathway negatively regulates TGF-β1-induced EMT in RLE-6TN cells and that DA-Raf1 (DA-Raf), a splicing isoform of A-Raf and a dominant-negative antagonist of the Ras-ERK pathway, plays an essential role in EMT. Stimulation of the cells with fibroblast growth factor 2 (FGF2), which activated the ERK pathway, prominently suppressed TGF-β1-induced EMT. An inhibitor of MEK, but not an inhibitor of phosphatidylinositol 3-kinase, rescued the TGF-β1-treated cells from the suppression of EMT by FGF2. Overexpression of a constitutively active mutant of a component of the Ras-ERK pathway, i.e., H-Ras, B-Raf, or MEK1, interfered with EMT. Knockdown of DA-Raf expression with siRNAs facilitated the activity of MEK and ERK, which were only weakly and transiently activated by TGF-β1. Although DA-Raf knockdown abrogated TGF-β1-induced EMT, the abrogation of EMT was reversed by the addition of the MEK inhibitor. Furthermore, DA-Raf knockdown impaired the TGF-β1-induced nuclear translocation of Smad2, which mediates the transcription required for EMT. These results imply that intrinsic DA-Raf exerts essential functions for EMT by antagonizing the TGF-β1-induced Ras-ERK pathway in RLE-6TN cells.

  13. Mechanisms of alveolar fibrosis after acute lung injury.

    Science.gov (United States)

    Marinelli, W A; Henke, C A; Harmon, K R; Hertz, M I; Bitterman, P B

    1990-12-01

    In patients who die after severe acute lung injury, a dramatic fibroproliferative response occurs within the alveolar air space, interstitium, and microvessels. Profound shunt physiology, dead space ventilation, and pulmonary hypertension are the physiologic consequences of this fibroproliferative response. The anatomic pattern of the response is unique within each alveolar compartment. For example, the air space is obliterated by granulation tissue, with replicating mesenchymal cells, their connective tissue products, and an expanding network of intra-alveolar capillaries. In contrast, the vascular fibroproliferative response is dominated by mesenchymal cell replication and connective tissue deposition within the walls of microvessels. Despite the unique anatomic features of these fibroproliferative processes, the regulatory signals involved are likely to be similar. Although our current understanding of the signals regulating the fibroproliferative response to acute lung injury is limited, inferences can be made from in vitro studies of mesenchymal cell behavior and several better understood fibroproliferative processes, including wound healing and chronic fibrotic lung diseases. As clinicians, our future ability to enhance effective lung repair will likely utilize therapeutic strategies specifically targeted to the signals that regulate the fibroproliferative process within the alveolar microenvironment.

  14. Hydrothermal growth of double-layer TiO{sub 2} nanostructure film for quantum dot sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Feng Shuanglong; Yang Junyou, E-mail: jyyang@mail.hust.edu.cn; Liu Ming; Zhu Hu; Zhang Jiansheng; Li Gen; Peng Jiangying; Liu Qiongzhen

    2012-01-31

    A double-layer (DL) film with a TiO{sub 2} nanosheet-layer on a layer of TiO{sub 2} nanorod-array, was synthesized on a transparent conductive fluorine-doped tin oxide substrate by a two-step hydrothermal method. Starting from the precursors of NaSeSO{sub 3}, CdSO{sub 4} and the complex of N(CH{sub 2}COOK){sub 3}, CdSe quantum dots (QDs) were grown on the DL-TiO{sub 2} substrate by chemical bath deposition method. The samples were characterized by X-ray diffraction, Scanning electron microscopy, Energy dispersion spectroscopy, and their optical scattering property was measured by light reflection spectrometry. Some CdSe QDs sensitized DL-TiO{sub 2} films serve as the photoanodes, were assembled into solar cell devices and their photovoltaic performance were also characterized. The short circuit current and open-circuit voltage of the solar cells range from 0.75 to 4.05 mA/cm{sup 2} and 0.20 - 0.42 V under the illumination of one sun (AM1.5, 100 mW/cm{sup 2}), respectively. The photocurrent density of the DL-TiO{sub 2} film is five times higher than that of a bare TiO{sub 2} nanorod array photoelectrode cell. - Highlights: Black-Right-Pointing-Pointer A two-step hydrothermal deposition method was used to deposit TiO{sub 2} films. Black-Right-Pointing-Pointer Double-layer TiO{sub 2} films were synthesized on transparent FTO substrate. Black-Right-Pointing-Pointer The bi-functional character of the electrode were confirmed. Black-Right-Pointing-Pointer Photocurrent density of DL-film electrode was enhanced 5 times than a single film.

  15. Polycrystalline thin-film TiO2/Se solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Nakada, T; Kunioka, A

    1985-07-01

    A new type of selenium solar cell with a titanium dioxide (TiO2)/Se heterojunction has been fabricated by low-cost process.An efficiency of 5.01 percent under AM 1.5 illumination (100 mW/sq cm) has been achieved without antireflection coatings. The corresponding short-circuit current density, open-circuit voltage, and fill factor are 10.8 mA/sq cm, 0.884 V, and 0.525, respectively.The efficiency is the highest among Se-based solar cells reported to date. These cells also have extremely high spectral response at short wavelengths, resulting in efficiencies of 11-13 percent under fluorescent light (500 lux). 10 references.

  16. Differential genomic effects of six different TiO2 nanomaterials on human liver HepG2 cells

    Science.gov (United States)

    Engineered nanoparticles are reported to cause liver toxicity in vivo. To better assess the mechanism of the in vivo liver toxicity, we used the human hepatocarcinoma cells (HepG2) as a model system. Human HepG2 cells were exposed to 6 TiO2 nanomaterials (with dry primary partic...

  17. Influence of different TiO{sub 2} blocking films on the photovoltaic performance of perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chenxi; Luo, Yudan; Chen, Xiaohong, E-mail: xhchen@phy.ecnu.edu.cn; Ou-Yang, Wei; Chen, Yiwei; Sun, Zhuo; Huang, Sumei, E-mail: smhuang@phy.ecnu.edu.cn

    2016-12-01

    Highlights: • TiO{sub 2} blocking layer (BL) was synthesized using various methods. • Effect of BL characteristics on performance of perovskite solar cell was studied. • Charge transfer kinetics of perovskite solar cells with different BLs was explored. • We demonstrated efficient solar cells employing chemical bath deposition based BLs. - Abstract: Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic (PV) cells. Cell structures based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive and brisk advances, holding great potential to grow into a mature PV technology. High power conversion efficiency (PCE) values have been obtained from the mesoscopic configuration in which a few hundred nano-meter thick mesoporous scaffold (e.g. TiO{sub 2} or Al{sub 2}O{sub 3}) infiltrated by perovskite absorber was sandwiched between the electron and hole transport layers. A uniform and compact hole-blocking layer is necessary for high efficient perovskite-based thin film solar cells. In this study, we investigated the characteristics of TiO{sub 2} compact layer using various methods and its effects on the PV performance of perovskite solar cells. TiO{sub 2} compact layer was prepared by a sol-gel method based on titanium isopropoxide and HCl, spin-coating of titanium diisopropoxide bis (acetylacetonate), screen-printing of Dyesol’s bocking layer titania paste, and a chemical bath deposition (CBD) technique via hydrolysis of TiCl{sub 4}, respectively. The morphological and micro-structural properties of the formed compact TiO{sub 2} layers were characterized by scanning electronic microscopy and X-ray diffraction. The analyses of devices performance characteristics showed that surface morphologies of TiO{sub 2} compact films played a critical role in affecting the efficiencies. The nanocrystalline TiO{sub 2} film deposited via the CBD route acts as the most efficient

  18. Enhanced photovoltaic properties in graphitic carbon nanospheres networked TiO{sub 2} nanocomposite based dye sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Radhe [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931 (United States); Sahoo, Satyaprakash, E-mail: satya504@gmail.com [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931 (United States); Chitturi, Venkateswara Rao [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931 (United States); Williams, Joseph D. [Department of Biomedical and Chemical Engineering, Syracuse University, L.C. Smith College of Engineering and Computer Science, Syracuse, NY (United States); Resto, Oscar [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931 (United States); Katiyar, Ram S., E-mail: rkatiyar@hpcf.uprrp.edu [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931 (United States)

    2015-08-25

    Highlights: • Nano size graphitic carbon nanospheres were prepared from MWCNTs. • TiO{sub 2}/GCNS composite was used as the photoanode in dye-sensitized solar cell. • An improved photovoltaic performance with GCNS–TiO{sub 2} composite was noticed. - Abstract: In this work, we report a novel carbon based TiO{sub 2} nanocomposite electron injection layer (photoanode) toward the improved performance of DSSCs. Graphitic carbon nanospheres (GCNSs) were synthesized by a unique acidic treatment of multi-wall carbon nanotubes. GCNS–TiO{sub 2} nanocomposites with different concentrations of GCNSs (ranging from 5 to 20 μL) were prepared to use as photoanodes in DSSCs. Structural and morphological properties of GCNS–TiO{sub 2} nanocomposites were analyzed by Raman spectroscopy and ultra-high resolution transmission electron microscopy techniques, respectively. A systematic increment in the short circuit current density (J{sub SC}) and open circuit voltage (V{sub OC}) of DSSC was observed by increasing GCNS concentration up to an optimal value, possibly due to the combined effect of slight rise in quasi-Fermi level and higher carrier transport rate in the resultant composite. Thus, a significant enhancement of ∼47% in the efficiency of DSSC containing GCNS–TiO{sub 2} photoanode was observed as compare to DSSC with pure TiO{sub 2} photoanode.

  19. Low-temperature fabrication of flexible TiO{sub 2} electrode for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Qinghui; Qi, Bin [Laboratory of Organic Optoelectronic Functional Materials and Molecular Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Zhong-guan-cun, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Zhong-guan-cun, Beijing 100190 (China); Yu, Yuan; Wu, Liangzhuan; Zhi, Jinfang [Laboratory of Organic Optoelectronic Functional Materials and Molecular Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Zhong-guan-cun, Beijing 100190 (China)

    2010-09-15

    A novel method for preparing flexible porous titania electrode from commercial TiO{sub 2} particles at low temperature for dye-sensitized solar cells (DSSCs) was introduced. In this method, hydroxypropyl methyl cellulose (HPMC) as an additive was added to form a good-quality TiO{sub 2}/HPMC film on indium-tin-oxide-coated polyethylene naphthalate flexible substrate (PEN/ITO). The additive was subsequently decomposed via the TiO{sub 2} photocatalytic degradation process under 365 nm UV-light illumination at room temperature to form flexible multiporous TiO{sub 2} electrode film. Electrochemistry impedance spectroscopy (EIS) analysis indicated that the resistance of TiO{sub 2} film markedly decreased, and photocurrent-voltage curves showed that the photocurrent dramatically increased when the additive (HPMC) was removed from the flexible titania electrode film. The photocurrent conversion efficiency was estimated at 3.25% under 100 mW/cm{sup 2} illuminations using this flexible film as the DSSC photoanode. Photocurrent versus voltages of the as-prepared flexible DSSCs under AM 1.5 at 100 mW/cm{sup 2} illumination: photoanode made from HPMC-free TiO{sub 2} paste ({open_square}) and photoanodes made from HPMC/TiO{sub 2} paste with UV-light illumination from 0 to 10 h. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  20. Three-dimensional self-branching anatase TiO{sub 2} nanorods with the improved carrier collection for SrTiO{sub 3}-based perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yajing; Wang, Chen; Tang, Ying; Huang, Lu [Department of Electronic Information Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Fu, Jianxun [Key Laboratory of Modern Metallurgy and Materials Processing, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Shi, Weimin; Wang, Linjun [Department of Electronic Information Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Yang, Weiguang, E-mail: wgyang@shu.edu.cn [Department of Electronic Information Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China)

    2016-09-15

    The organic–inorganic perovskite solar cells based on ternary oxide SrTiO{sub 3} shows a higher Voc, attributed to its slightly higher conduction band edge and better morphology of absorber material. However, its less efficient carrier collection and limited overall interfacial areas between the absorber material and the electron-transport layer (ETL), dramatically reducing the Jsc. Here, By adjusting the concentrations of the Ti(OBu){sub 4}, we successfully prepared the three-dimensional (3D) self-branching anatase TiO{sub 2} nanorod/SrTiO{sub 3} nanocomposites, and slightly tuned the particle size of SrTiO{sub 3}. With the incorporation of the three-dimensional (3D) self-branching anatase TiO{sub 2} nanorod, the Jsc of the device based on SrTiO{sub 3} was highly boosted. The best performing solar cell we obtained exhibited a PCE of 9.99% with a Jsc of 19.48 mA/cm{sup 2}. The excellent performance could be ascribed to the improvement of charge carrier collection of SrTiO{sub 3}, better surface coverage and crystallinity of CH{sub 3}NH{sub 3}PbI{sub 3}, and enhanced light scattering ability caused by 3D self-branching anatase TiO{sub 2} nanorods. - Highlights: • The three-dimensional (3D) self-branching anatase TiO{sub 2} nanorod/SrTiO{sub 3} nanocomposites were prepared. • The particle sizes of SrTiO{sub 3} can be slightly tuned. • The best performing solar cell we obtained exhibited a PCE of 9.99% with the Jsc of 19.48 mA/cm{sup 2}.

  1. TiO2 nanoparticles disrupt cell adhesion and the architecture of cytoskeletal networks of human osteoblast-like cells in a size dependent manner.

    Science.gov (United States)

    Ibrahim, Mohamed; Schoelermann, Julia; Mustafa, Kamal; Cimpan, Mihaela R

    2018-04-30

    Human exposure to titanium dioxide nanoparticles (nano-TiO 2 ) is increasing. An internal source of nano-TiO 2 is represented by titanium-based orthopedic and dental implants can release nanoparticles (NPs) upon abrasion. Little is known about how the size of NPs influences their interaction with cytoskeletal protein networks and the functional/homeostatic consequences that might follow at the implant-bone interface with regard to osteoblasts. We investigated the effects of size of anatase nano-TiO 2 on SaOS-2 human osteoblast-like cells exposed to clinically relevant concentrations (0.05, 0.5, 5 mg/L) of 5 and 40 nm spherical nano-TiO 2 . Cell viability and proliferation, adhesion, spread and migration were assessed, as well as the orientation of actin and microtubule cytoskeletal networks. The phosphorylation of focal adhesion kinase (p-FAK Y397 ) and the expression of vinculin in response to nano-TiO 2 were also assessed. Treatment with nano-TiO 2 disrupted the actin and microtubule cytoskeletal networks leading to morphological modifications of SaOS-2 cells. The phosphorylation of p-FAK Y397 and the expression of vinculin were also modified depending on the particle size, which affected cell adhesion. Consequently, the cell migration was significantly impaired in the 5 nm-exposed cells compared to unexposed cells. The present work shows that the orientation of cytoskeletal networks and the focal adhesion proteins and subsequently the adhesion, spread and migration of SaOS-2 cells were affected by the selected nano-TiO 2 in a size dependent manner. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

  2. Rapid fabrication of mesoporous TiO2 thin films by pulsed fibre laser for dye sensitized solar cells

    Science.gov (United States)

    Hadi, Aseel; Alhabradi, Mansour; Chen, Qian; Liu, Hong; Guo, Wei; Curioni, Michele; Cernik, Robert; Liu, Zhu

    2018-01-01

    In this paper we demonstrate for the first time that a fibre laser with a wavelength of 1070 nm and a pulse width of milliseconds can be applied to generate mesoporous nanocrystalline (nc) TiO2 thin films on ITO coated glass in ambient atmosphere, by complete vaporisation of organic binder and inter-connection of TiO2 nanoparticles, without thermally damaging the ITO layer and the glass substrate. The fabrication of the mesoporous TiO2 thin films was achieved by stationary laser beam irradiation of 1 min. The dye sensitized solar cell (DSSC) with the laser-sintered TiO2 photoanode reached higher power conversion efficiency (PCE) of 3.20% for the TiO2 film thickness of 6 μm compared with 2.99% for the furnace-sintered. Electrochemical impedance spectroscopy studies revealed that the laser sintering under the optimised condition effectively decreased charge transfer resistance and increased electron lifetime of the TiO2 thin films. The use of the fibre laser with over 40% wall-plug efficiency offers an economically-feasible, industrial viable solution to the major challenge of rapid fabrication of large scale, mass production of mesoporous metal oxide thin film based solar energy systems, potentially for perovskite and monolithic tandem solar cells, in the future.

  3. Ultrasonic Spray-Coating of Large-Scale TiO2 Compact Layer for Efficient Flexible Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Peng Zhou

    2017-02-01

    Full Text Available Flexible electronics have attracted great interest in applications for the wearable devices. Flexible solar cells can be integrated into the flexible electronics as the power source for the wearable devices. In this work, an ultrasonic spray-coating method was employed to deposit TiO2 nanoparticles on polymer substrates for the fabrication of flexible perovskite solar cells (PSCs. Pre-synthesized TiO2 nanoparticles were first dispersed in ethanol to prepare the precursor solutions with different concentrations (0.5 mg/mL, 1.0 mg/mL, 2.0 mg/mL and then sprayed onto the conductive substrates to produce compact TiO2 films with different thicknesses (from 30 nm to 150 nm. The effect of the different drying processes on the quality of the compact TiO2 film was studied. In order to further improve the film quality, titanium diisopropoxide bis(acetylacetonate (TAA was added into the TiO2-ethanol solution at a mole ratio of 1.0 mol % with respect to the TiO2 content. The final prepared PSC devices showed a power conversion efficiency (PCE of 14.32% based on the indium doped tin oxide coated glass (ITO-glass substrate and 10.87% on the indium doped tin oxide coated polyethylene naphthalate (ITO-PEN flexible substrate.

  4. Influence of VB group doped TiO2 on photovoltaic performance of dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Liu, Jia; Duan, Yandong; Zhou, Xiaowen; Lin, Yuan

    2013-01-01

    Dye-sensitized solar cell with V B group (vanadium (V), niobium (Nb) and tantalum (Ta)) doped TiO 2 prepared by hydrothermal method shows a higher photovoltaic efficiency compared with the undoped TiO 2 . All the V B doping shift the flat band potential positively and increase the doping density which is investigated by Mott–Schottky plot. The positive shift of flat band potential improves the driving force of injecting electron from the LUMO of dye to the conduction band of TiO 2 and the photocurrent. On the other hand, the increase of doping density accelerates transfer rate of electrons in TiO 2 than the un-doped, which is confirmed by intensity-modulated photocurrent. V-, Nb-, Ta-doped TiO 2 exhibited photovoltaic performance with 7.80%, 8.33%, 8.18%, respectively, compared with that of the cells based on pure TiO 2 (7.42%).

  5. Photochemical solar cells based on dye-sensitization of nanocrystalline TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Deb, S.K.; Ellingson, R.; Ferrere, S.; Frank, A.J.; Gregg, B.A.; Nozik, A.J.; Park, N.; Schlichthoerl, G. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    A photoelectrochemical solar cell that is based on the dye-sensitization of thin nanocrystalline films of TiO{sub 2} (anatase) nanoparticles in contact with a non-aqueous liquid electrolyte is described. The cell, fabricated at NREL, shows a conversion efficiency of {approximately} 9.2% at AM1.5, which approaches the best reported value of 10--11% by Graetzel at EPFL in Lausanne, Switzerland. The femtosecond (fs) pump-probe spectroscopy has been used to time resolve the injection of electrons into the conduction band of nanocrystalline TiO{sub 2} films under ambient conditions following photoexcitation of the adsorbed Ru(II)-complex dye. The measurement indicates an instrument-limited {minus}50 fs upper limit on the electron injection time. The authors also report the sensitization of nanocrystalline TiO{sub 2} by a novel iron-based dye, CIS-[Fe{sup II}(2,2{prime}-bipyridine-4,4,{prime}-dicarboxylic acid){sub 2}(CN){sub 2}], a chromophore with an extremely short-lived, nonemissive excited state. The dye also exhibits a unique band selective sensitization through one of its two absorption bands. The operational principle of the device has been studied through the measurement of electric field distribution within the device structure and studies on the pH dependence of dye-redox potential. The incorporation of WO{sub 3}-based electrochromic layer into this device has led to a novel photoelectrochromic device structure for smart window application.

  6. The Effect of Calcination Temperature on the Performance of TiO2 Aggregates-based Dye Solar Cells (DSCs)

    International Nuclear Information System (INIS)

    Siti Nur Azella Zaine; Norani Muti Mohamed; Mohamad Azmi Bustam

    2011-01-01

    In this paper, the effect of calcination temperature on the physicochemical properties of synthesized TiO 2 aggregates and their influence on overall light conversion efficiency of dye solar cell (DSc) were investigated. Samples of TiO 2 aggregates (mean size of 0.45 μm) composing of nano crystallites (10-40 nm) were synthesized through hydrolysis of dilute titanium alkoxide in ethanol. Phase and microstructure of the TiO 2 obtained have been characterized using FESEM, XRD and UV-Vis spectroscopy. I-V characterization shows that TiO 2 aggregates based DSC demonstrated better performance compared to nanoparticles (P-25)-based DSC. The optimum calcination temperature was found to be about 500 degree Celsius with efficiency of 4.456 %, which is 30 % increment compared to P-25-based DSC under the same condition. (author)

  7. Ion beam modification of TiO2 films prepared by Cat-CVD for solar cell

    International Nuclear Information System (INIS)

    Narita, Tomoki; Iida, Tamio; Ogawa, Shunsuke; Mizuno, Kouichi; So, Jisung; Kondo, Akihiro; Yoshida, Norimitsu; Itoh, Takashi; Nonomura, Shuichi; Tanaka, Yasuhito

    2008-01-01

    The effects of nitrogen ion bombardment on TiO 2 films prepared by the Cat-CVD method have been studied to improve the optical and electrical properties of the material for use in Si thin film solar cells. The refractive index n and the dark conductivity of the TiO 2 film increased with irradiation time. The refractive index n of the TiO 2 film was changed from 2.1 to 2.4 and the electrical conductivity was improved from 3.4 x 10 -2 to 1.2 x 10 -1 S/cm by the irradiation. These results are due to the formation of Ti-N bonds and oxygen vacancies in the film

  8. Improved performance of dye-sensitized solar cells with surface-treated TiO2 as a photoelectrode

    International Nuclear Information System (INIS)

    Park, Su Kyung; Chung, Chinkap; Kim, Dae-Hwan; Kim, Cham; Lee, Sang-Ju; Han, Yoon Soo

    2012-01-01

    We report on the effects of surface-modified TiO 2 on the performance of dye-sensitized solar cells (DSSCs). TiO 2 surface was modified with Na 2 CO 3 via a simple dip coating process and the modified TiO 2 was applied to photoelectrodes of DSSCs. By dipping of TiO 2 layer into aqueous Na 2 CO 3 solution, the DSSC showed a power conversion efficiency of 9.98%, compared to that (7.75%) of the reference device without surface treatment. The UV–vis absorption spectra, the impedance spectra and the dark current studies revealed that the increase of all parameters was attributed to the enhanced dye adsorption, the prolonged electron lifetime and the reduced interfacial resistance.

  9. Development of Perovskite Sensitized Thin Film Solar Cells Based on Graphene Oxide/TiO2 Photoanodes

    Directory of Open Access Journals (Sweden)

    Momina KHANNAM

    2017-03-01

    Full Text Available Graphene oxide/TiO2(GO/TiO2 nanocomposites with different concentrations of GO were prepared by a self-assemble method. The synthesized GO/TiO2 nanocomposites are characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopic (TEM analysis. Using these GO/TiO2 nanocomposites as an electron collection layer a series of solid state perovskite sensitized solar cells were fabricated. The photovoltaic properties like short circuit current density and photo conversion efficiency of the fabricated device were evaluated. It was noticed that the nanocomposites has significant effects on the photovoltaic properties of the device. With increase in the amount of GO in the nanocomposites the short circuit current density of the devices increased from 1.79 to 4.65 mAcm-2 and the photo conversion efficiency increased from 0.413 to 1.34 %.

  10. Nb-TiO{sub 2}/polymer hybrid solar cells with photovoltaic response under inert atmosphere conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lira-Cantu, Monica; Khoda Siddiki, Mahbube; Munoz-Rojas, David; Amade, Roger [Centre d' Investigacio en Nanociencia i Nanotecnologia (CIN2, CSIC), Laboratory of Nanostructured Materials for Photovoltaic Energy, Campus UAB, Barcelona (Spain); Gonzalez-Pech, Natalia I. [Centre d' Investigacio en Nanociencia i Nanotecnologia (CIN2, CSIC), Laboratory of Nanostructured Materials for Photovoltaic Energy, Campus UAB, Barcelona (Spain); Instituto Tecnologico y de Estudios Superiores de Monterrey (ITESM), Ave. Eugenio Garza Sada, 64640 Monterrey, N.L. (Mexico)

    2010-07-15

    Hybrid Solar Cells (HSC) applying Nb-TiO{sub 2} in direct contact with a conducting organic polymer, MEH-PPV, show higher stability than the bare TiO{sub 2}-based HSC when analyzed under inert atmosphere conditions. IPCE analyses revealed that inert atmospheres affect directly the semiconductor oxide in the first stages of the analyses but photovoltaic performance stabilizes after several hours. A 20 wt% Nb-doped TiO{sub 2} presented the highest stability and photovoltaic properties. The behavior has been attributed to the solubility limit of Nb within the TiO{sub 2} beyond 20 wt% doping level where the co-existence of NbO{sub 2} is observed. The HSCs were analyzed under controlled N{sub 2} atmosphere and 1000 W/m{sup 2} (AM 1.5) irradiation. (author)

  11. Preparation of TiO{sub 2} films by layer-by-layer assembly and their application in solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L. [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Anhui Key Laboratory of Spin Electron and Nanomaterials (Cultivating Base), Suzhou University, Suzhou 234000 (China); Xie, A.J. [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Shen, Y.H., E-mail: s_yuhua@163.co [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Li, S.K. [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China)

    2010-09-03

    Polyacrylate sodium (PAAS)/titania (TiO{sub 2}) multilayers have been fabricated through the electrostatic layer-by-layer assembly technique. The composite films display an excellent photovoltaic performance after sintering and sensitization by cyanine dye (CD), which can be applied in dye-sensitized solar cells. The properties of PAAS/TiO{sub 2} multilayers are investigated by ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), X-ray diffraction analysis (XRD), Thermogravimetric analysis (TGA), and photovoltaic measurements. The results indicate that the thermal stability of the PAAS has a direct influence on the performance of dye-sensitized solar cells. The energy conversion efficiency of approximately 1.29% was obtained for dye-sensitized solar cell with TiO{sub 2}/PAAS (40 bilayers) as precursor film. In addition, the composite films also show a good self-cleaning property for photocatalytic degradation of methylene blue.

  12. Eosin Y-sensitized nanostructured SnO{sup 2}/TiO{sup 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Tai, Weon-Pil [Institute of Advanced Materials, Inha University, Yonghyun-dong, Nam-ku, Inchon 402-751 (South Korea); Inoue, Kozo [National Institute of Advanced Industrial Science and Technology, Tosu, Saga 841-0052 (Japan)

    2003-02-01

    The photoelectrochemical behaviors of eosin Y (organic dye)-sensitized nanostructured SnO{sub 2}/TiO{sub 2} coupled and SnO{sub 2}+TiO{sub 2} composite solar cells were studied. The value of incident photon-to-current conversion efficiency (IPCE) in the coupled system was higher than the composite system. A maximum IPCE value, 63%, was reached at 525 nm wavelength in the coupled cell with 3.5-{mu}m-thick SnO{sub 2} and 7-{mu}m-thick TiO{sub 2}. The IPCE difference in the coupled and composite cells sensitized by eosin Y dye is discussed.

  13. BiOI/TiO{sub 2}-nanorod array heterojunction solar cell: Growth, charge transport kinetics and photoelectrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lingyun; Daoud, Walid A., E-mail: wdaoud@cityu.edu.hk

    2015-01-01

    Highlights: • BiOI/TiO{sub 2} photoanodes were fabricated by a simple solvothermal/hydrothermal method. • BiOI/TiO{sub 2} (PVP) showed a 13-fold increase in photocurrent density compared to TiO{sub 2}. • Charge transport kinetics within the BiOI/TiO{sub 2} heterojunctions are discussed. - Abstract: A series of BiOI/TiO{sub 2}-nanorod array photoanodes were grown on fluorine-doped tin oxide (FTO) glass using a simple two-step solvothermal/hydrothermal method. The effects of the hydrothermal process, such as TiO{sub 2} nanorod growth time, BiOI concentration and the role of surfactant, polyvinylpyrrolidone (PVP), on the growth of BiOI, were investigated. The heterojunctions were characterized by X-ray diffraction, UV–vis absorbance spectroscopy and scanning electron microscopy. The photoelectrochemical properties of the as-grown junctions, such as linear sweep voltammetry (LSV) behavior, photocurrent response and incident photon-to-electron conversion efficiency (IPCE) under Xenon lamp illumination, are presented. The cell with BiOI/TiO{sub 2} (PVP) as photoanode can reach a short current density (J{sub sc}) of 0.13 mA/cm{sup 2} and open circuit voltage (V{sub oc}) of 0.46 V vs. Ag/AgCl under the irradiation of a 300 W Xenon lamp. Compared to bare TiO{sub 2}, the IPCE of BiOI/TiO{sub 2} (PVP) increased 4–5 times at 380 nm. Furthermore, the charge transport kinetics within the heterojunction is also discussed.

  14. BiOI/TiO2-nanorod array heterojunction solar cell: Growth, charge transport kinetics and photoelectrochemical properties

    International Nuclear Information System (INIS)

    Wang, Lingyun; Daoud, Walid A.

    2015-01-01

    Highlights: • BiOI/TiO 2 photoanodes were fabricated by a simple solvothermal/hydrothermal method. • BiOI/TiO 2 (PVP) showed a 13-fold increase in photocurrent density compared to TiO 2 . • Charge transport kinetics within the BiOI/TiO 2 heterojunctions are discussed. - Abstract: A series of BiOI/TiO 2 -nanorod array photoanodes were grown on fluorine-doped tin oxide (FTO) glass using a simple two-step solvothermal/hydrothermal method. The effects of the hydrothermal process, such as TiO 2 nanorod growth time, BiOI concentration and the role of surfactant, polyvinylpyrrolidone (PVP), on the growth of BiOI, were investigated. The heterojunctions were characterized by X-ray diffraction, UV–vis absorbance spectroscopy and scanning electron microscopy. The photoelectrochemical properties of the as-grown junctions, such as linear sweep voltammetry (LSV) behavior, photocurrent response and incident photon-to-electron conversion efficiency (IPCE) under Xenon lamp illumination, are presented. The cell with BiOI/TiO 2 (PVP) as photoanode can reach a short current density (J sc ) of 0.13 mA/cm 2 and open circuit voltage (V oc ) of 0.46 V vs. Ag/AgCl under the irradiation of a 300 W Xenon lamp. Compared to bare TiO 2 , the IPCE of BiOI/TiO 2 (PVP) increased 4–5 times at 380 nm. Furthermore, the charge transport kinetics within the heterojunction is also discussed

  15. Effect of microstructure of TiN film on properties as bipolar plate coatings in polymer electrolyte membrane fuel cell prepared by inductively coupled plasma assisted magnetron sputtering

    International Nuclear Information System (INIS)

    Feng, Kai; Li, Zhuguo

    2013-01-01

    As potential application in bipolar plate of polymer electrolyte membrane fuel cell, the microstructure, corrosion resistance and the electrical conductivity of titanium nitride (TiN) and Si doped titanium nitride (Ti 0.9 Si 0.1 N) films deposited by magnetron sputtering with different bias voltages are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), electrochemical test and four-point probe method, respectively. XRD, SEM and AFM results reveal that the texture and topography of TiN film depend on the bias voltage and incorporation of Si. When the bias voltage is − 20 V and − 30 V, the TiN and Ti 0.9 Si 0.1 N films exhibit a dense (111) plane preferred growth, denser structure and smoother surface topography. The potentiodynamic test results indicate that the TiN and Ti 0.9 Si 0.1 N films have higher chemical inertness and better corrosion resistance. The films can satisfy the requirement of current density for bipolar plate materials. Incorporation of Si element into TiN film makes the passive current density more stable. Four-point probe measurement results show that the resistivity of both TiN and Ti 0.9 Si 0.1 N films reaches minimum when the deposition bias voltage is − 20 V. - Highlights: • Dense TiN and Ti 0.9 Si 0.1 N films are deposited by magnetron sputtering. • Preferred growth orientation of TiN depends on the bias voltage and Si doping. • TiN and Ti 0.9 Si 0.1 N films have excellent corrosion resistance. • Surface conductivity of TiN and Ti 0.9 Si 0.1 N films evolves with bias voltage

  16. Radon-induced bronchiolo-alveolar tumors in rats: cytologic and microinvasive characteristics

    International Nuclear Information System (INIS)

    Busch, R.H.; Cross, R.; Bair, W.

    1983-07-01

    A series of 39 rat lung tumors induced by radon and radon daughters alone or in conjunction with uranium ore dust exposure were studied by light microscopy, transmission electron microscopy, and scanning electron microscopy. Using absence of appreciable mucus, mucuos granules, tonofibrils, and desmosomes, and the presence of alveolar Type II cell inclusions as criteria, all were confirmed as bronchiolo-alveolar (B-A) tumors with predominantly Type II cell characteristics

  17. Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

    Directory of Open Access Journals (Sweden)

    Meng Qin

    2017-06-01

    Full Text Available This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La, Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries.

  18. Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

    Science.gov (United States)

    Qin, Meng; Li, Yueming; Lv, Xiao-Jun

    2017-01-01

    This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La), Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries. PMID:28632167

  19. Simulation of lung alveolar epithelial wound healing in vitro.

    Science.gov (United States)

    Kim, Sean H J; Matthay, Michael A; Mostov, Keith; Hunt, C Anthony

    2010-08-06

    The mechanisms that enable and regulate alveolar type II (AT II) epithelial cell wound healing in vitro and in vivo remain largely unknown and need further elucidation. We used an in silico AT II cell-mimetic analogue to explore and better understand plausible wound healing mechanisms for two conditions: cyst repair in three-dimensional cultures and monolayer wound healing. Starting with the analogue that validated for key features of AT II cystogenesis in vitro, we devised an additional cell rearrangement action enabling cyst repair. Monolayer repair was enabled by providing 'cells' a control mechanism to switch automatically to a repair mode in the presence of a distress signal. In cyst wound simulations, the revised analogue closed wounds by adhering to essentially the same axioms available for alveolar-like cystogenesis. In silico cell proliferation was not needed. The analogue recovered within a few simulation cycles but required a longer recovery time for larger or multiple wounds. In simulated monolayer wound repair, diffusive factor-mediated 'cell' migration led to repair patterns comparable to those of in vitro cultures exposed to different growth factors. Simulations predicted directional cell locomotion to be critical for successful in vitro wound repair. We anticipate that with further use and refinement, the methods used will develop as a rigorous, extensible means of unravelling mechanisms of lung alveolar repair and regeneration.

  20. Simulation on the Performance of Dye Solar Cell Incorporated with TiO2 Passivation Layer

    Directory of Open Access Journals (Sweden)

    Unan Yusmaniar Oktiawati

    2016-01-01

    Full Text Available Dye Solar Cell (DSC has started to gain interest in the recent years for practical application because of its ecofriendly, low cost, and easy fabrication. However, its efficiency is still not as competitive as the conventional silicon based solar cell. One of the research efforts to improve the efficiency of DSC is to use the passivation layer in between the photoelectrode material and the conductive oxide substrate. Thus, the objective of this simulation study is to investigate the effect of passivation layer on the performance of DSC. Properties from literatures which are based on physical work were captured as the input for the simulation using process, ATHENA, and device, ATLAS, simulator. Results have shown that the addition of two-20 nm TiO2 passivation layers on DSC can enhance the efficiency by 11% as the result of less recombination, higher electron mobility, and longer electron lifetime.

  1. Effect of various concentrations of Ti in hydrocarbon plasma polymer films on the adhesion, proliferation and differentiation of human osteoblast-like MG-63 cells

    Energy Technology Data Exchange (ETDEWEB)

    Vandrovcova, Marta, E-mail: marta.vandrovcova@fgu.cas.cz [Department of Biomaterials and Tissue Engineering, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4 (Czech Republic); Grinevich, Andrey; Drabik, Martin; Kylian, Ondrej; Hanus, Jan [Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 182 00 Prague 8 (Czech Republic); Stankova, Lubica; Lisa, Vera [Department of Biomaterials and Tissue Engineering, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4 (Czech Republic); Choukourov, Andrei; Slavinska, Danka; Biederman, Hynek [Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 182 00 Prague 8 (Czech Republic); Bacakova, Lucie [Department of Biomaterials and Tissue Engineering, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4 (Czech Republic)

    2015-12-01

    Graphical abstract: - Highlights: • Hydrocarbon plasma polymer films with Ti in concentration of 0–20 at.% were prepared. • The Ti concentration was positively correlated with the material surface wettability. • The optimum Ti concentrations for the MG-63 cells behavior were identified. • The Ti concentration also influenced the cell immune activation. - Abstract: Hydrocarbon polymer films (ppCH) enriched with various concentrations of titanium were deposited on microscopic glass slides by magnetron sputtering from a Ti target. The maximum concentration of Ti (about 20 at.%) was achieved in a pure argon atmosphere. The concentration of Ti decreased rapidly after n-hexane vapors were introduced into the plasma discharge, and reached zero values at n-hexane flow of 0.66 sccm. The decrease in Ti concentration was associated with decreasing oxygen and titanium carbide concentration in the films, decreasing wettability (the water drop contact angle increased from 20° to 91°) and decreasing root-mean-square roughness (from 3.3 nm to 1.0 nm). The human osteoblast-like MG-63 cells cultured on pure ppCH films and on films with 20 at.% of Ti showed relatively high concentrations of ICAM-1, a marker of cell immune activation. Lower concentrations of Ti (mainly 5 at.%) improved cell adhesion and osteogenic differentiation, as revealed by higher concentrations of talin, vinculin and osteocalcin. Higher Ti concentrations (15 at.%) supported cell growth, as indicated by the highest final cell population densities on day 7 after seeding. Thus, enrichment of ppCH films with appropriate concentrations of Ti makes these films more suitable for potential coatings of bone implants.

  2. Application of nitrogen-doped TiO{sub 2} nano-tubes in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Vy Anh; Truong, Trieu Thinh; Phan, Thu Anh Pham; Nguyen, Trang Ngoc [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Huynh, Tuan Van [Faculty of Physics and Engineering Physics, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Agresti, Antonio; Pescetelli, Sara [CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome Tor Vergata (Italy); Le, Tien Khoa [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Di Carlo, Aldo [CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome Tor Vergata (Italy); Lund, Torben [Department of Science and Environment, Roskilde University, DK-4000 (Denmark); Le, So-Nhu [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Nguyen, Phuong Tuyet, E-mail: ngtuyetphuong@gmail.com [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam)

    2017-03-31

    Highlights: • N-doped TiO{sub 2} nanotubes are synthesized by alkaline hydrothermal and reflux method. • Formation of TiO{sub 2} nanotube morphology and anatase phase is shown by TEM, XRD, Raman. • Coordination of NH{sub 4}{sup +} via Ti−O−NH{sub 4}{sup +} or H{sub 4}N{sup +}−Ti−O bonds is indicated by FT-IR and XPS. • Blocking effect of N-doped toward electron transfer on TiO{sub 2} anode is studied by CV. • N-doped TiO{sub 2} improved DSC performance up to 30–40% mainly due to an increase in J{sub sc}. - Abstract: Our research aimed to improve the overall energy conversion efficiency of DSCs by applying nitrogen-doped TiO{sub 2} nano-tubes (N-TNT) for the preparation of DSCs photo-anodes. The none-doped TiO{sub 2} nano-tubes (TNTs) were synthesized by alkaline hydrothermal treatment of Degussa P25 TiO{sub 2} particles in 10 M NaOH. The nano-tubes were N-doped by reflux in various concentrations of NH{sub 4}NO{sub 3}. The effects of nitrogen doping on the structure, morphology, and crystallography of N-TNT were analyzed by transmission electron microscopy (TEM), infrared spectroscopy (IR), Raman spectroscopy, and X-ray photoelectron spectra (XPS). DSCs fabricated with doped N-TNT and TNT was characterized by J-V measurements. Results showed that nitrogen doping significantly enhanced the efficiency of N-TNT cells, reaching the optimum value (η = 7.36%) with 2 M nitrogen dopant, compared to η = 4.75% of TNT cells. The high efficiency of the N-TNT cells was attributed to increased current density due to the reduction of dark current in the DSCs.

  3. Annealing Effect on Photovoltaic Performance of CdSe Quantum-Dots-Sensitized TiO2 Nanorod Solar Cells

    Directory of Open Access Journals (Sweden)

    Yitan Li

    2012-01-01

    Full Text Available Large area rutile TiO2 nanorod arrays were grown on F:SnO2 (FTO conductive glass using a hydrothermal method at low temperature. CdSe quantum dots (QDs were deposited onto single-crystalline TiO2 nanorod arrays by a chemical bath deposition (CBD method to make a photoelectrode. The solar cell was assembled using a CdSe-TiO2 nanostructure as the photoanode and polysulfide solution as the electrolyte. The annealing effect on optical and photovoltaic properties of CdSe quantum-dots-sensitized TiO2 nanorod solar cells was studied systematically. A significant change of the morphology and a regular red shift of band gap of CdSe nanoparticles were observed after annealing treatment. At the same time, an improved photovoltaic performance was obtained for quantum-dots-sensitized solar cell using the annealed CdSe-TiO2 nanostructure electrode. The power conversion efficiency improved from 0.59% to 1.45% as a consequence of the annealing effect. This improvement can be explained by considering the changes in the morphology, the crystalline quality, and the optical properties caused by annealing treatment.

  4. Study on copper oxide stability in photoelectrochemical cell composed of nanostructured TiO2 and CuxO electrodes

    International Nuclear Information System (INIS)

    Juodkazytė, J.; Šebeka, B.; Savickaja, I.; Jagminas, A.; Jasulaitienė, V.; Selskis, A.; Kovger, J.; Mack, P.

    2014-01-01

    Highlights: • Performance of Ti|TiO 2 | 0.1 M KOH |Cu x O|Cu photoelectrochemical cell is investigated. • Recrystallization of nanostructured Cu x O layer during photoelectrolysis is observed. • Comprehensive analysis of possible photoelectrochemical reactions is presented. • Factors influencing stability of Cu/Cu x O photocathode are discussed. • An important role of H 2 O 2 in operation of PEC is revealed. - Abstract: In the present study the performance of photoelectrochemical cell composed of nanostructurized Cu x O and TiO 2 photoelectrodes short-circuited in side by side configuration in 0.1 M KOH is investigated with the purpose to test the stability of Cu/Cu x O photocathode. The techniques employed are X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy and voltammetry. Comprehensive analysis of possible electrochemical reactions, involving participation of photogenerated charge carriers is presented. Recrystallization of Cu x O layer accompanied by the change in photocathode color is found to occur during the photoelectrolysis. The influence of structural factors, the potential of conjugated electrodes and hydrogen peroxide, which forms as intermediate during photoelectrolysis, on the balance of cathodic reactions and stability of operation of Ti|TiO 2 | 0.1 M KOH | Cu x O|Cu photoelectrochemical cell is discussed

  5. Microscopy of hierarchically organized TiO{sub 2} photoelectrode for dye solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Eskandar, A., E-mail: aeska07@gmail.com [Department of Electrical and Electronics, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia); Mohamed, N. M., E-mail: noranimuti-mohamed@petronas.com.my [Centre of Innovative Nanostructures and Nanodevices, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia)

    2015-07-22

    Research on improving the performance of dye solar cells has various aspects of the device being investigated. This paper analyzes the deliberately hierarchized photoelectrode configuration for DSC applications to improve the performance of DSCs. Multiple layers of differently composed TiO{sub 2} particle types namely aggregates and nanoparticles were deposited to form a photoelectrode with thickness of about 12 µm. The photoelectrodes were assembled into working DSCs with an active area of 1 cm{sup 2}. Measurement for solar power conversion performance was measured under 1 sun at AM1.5 spectrum simulated sunlight. Electron microscopy for photoelectrode analysis was conducted using Field Emission Scattering Electron Microscopy with enhanced resolution. External Quantum Efficiency was measured using a purpose built instrument. Kinetics were investigated using the Electrochemical Impedance Spectroscopy (EIS) measurement with a potentiostat. The best performing DSC is of the hierarchically organized photoelectrode with a photoconversion efficiency of 4.58%, an increase of 14% in comparison to the reference samples with fully aggregates configuration. Short circuit current density, Jsc increases by about 2.223 mA cm{sup −2} relative to the blanks. The electron microscopy confirmed expected thickness at around 10 µm and layers forming the photoelectrode being hierarchically deposited with ∼20 nm TiO{sub 2} nanoparticles and 450 nm TiO{sub 2} aggregates mixture composition. EQE improved especially for visible region of 500-550 nm light wavelengths with 12 % increase in the response of in that region. Improvement to the diffusion coefficient as measured by the EIS contributed to the performance increase of the photoelectrode configuration under investigation.

  6. Disturbed mitotic progression and genome segregation are involved in cell transformation mediated by nano-TiO2 long-term exposure

    International Nuclear Information System (INIS)

    Huang Shing; Chueh Pinju; Lin Yunwei; Shih Tungsheng; Chuang Showmei

    2009-01-01

    Titanium dioxide (TiO2) nano-particles (< 100 nm in diameter) have been of interest in a wide range of applications, such as in cosmetics and pharmaceuticals because of their low toxicity. However, recent studies have shown that TiO2 nano-particles (nano-TiO2) induce cytotoxicity and genotoxicity in various lines of cultured cells as well as tumorigenesis in animal models. The biological roles of nano-TiO2 are shown to be controversial and no comprehensive study paradigm has been developed to investigate their molecular mechanisms. In this study, we showed that short-term exposure to nano-TiO2 enhanced cell proliferation, survival, ERK signaling activation and ROS production in cultured fibroblast cells. Moreover, long-term exposure to nano-TiO2 not only increased cell survival and growth on soft agar but also the numbers of multinucleated cells and micronucleus (MN) as suggested in confocal microscopy analysis. Cell cycle phase analysis showed G2/M delay and slower cell division in long-term exposed cells. Most importantly, long-term TiO2 exposure remarkably affected mitotic progression at anaphase and telophase leading to aberrant multipolar spindles and chromatin alignment/segregation. Moreover, PLK1 was demonstrated as the target for nano-TiO2 in the regulation of mitotic progression and exit. Notably, a higher fraction of sub-G1 phase population appeared in TiO2-exposed cells after releasing from G2/M synchronization. Our results demonstrate that long-term exposure to nano-TiO2 disturbs cell cycle progression and duplicated genome segregation, leading to chromosomal instability and cell transformation.

  7. Particle Size Effects of TiO2 Layers on the Solar Efficiency of Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Ming-Jer Jeng

    2013-01-01

    Full Text Available Large particle sizes having a strong light scattering lead to a significantly decreased surface area and small particle sizes having large surface area lack light-scattering effect. How to combine large and small particle sizes together is an interesting work for achieving higher solar efficiency. In this work, we investigate the solar performance influence of the dye-sensitized solar cells (DSSCs by the multiple titanium oxide (TiO2 layers with different particle sizes. It was found that the optimal TiO2 thickness depends on the particle sizes of TiO2 layers for achieving the maximum efficiency. The solar efficiency of DSSCs prepared by triple TiO2 layers with different particle sizes is higher than that by double TiO2 layers for the same TiO2 thickness. The choice of particle size in the bottom layer is more important than that in the top layer for achieving higher solar efficiency. The choice of the particle sizes in the middle layer depends on the particle sizes in the bottom and top layers. The mixing of the particle sizes in the middle layer is a good choice for achieving higher solar efficiency.

  8. The Function of TiO2 with Respect to Sensitizer Stability in Nanocrystalline Dye Solar Cells

    Directory of Open Access Journals (Sweden)

    A. Barkschat

    2008-01-01

    Full Text Available Dyes of characteristically different composition have been tested with respect to long-term stability in operating standardized dye sensitized cells during a time period of up to 3600 hours. Selective solar illumination, the use of graded filters, and imaging of photocurrents revealed that degradation is linked to the density of photocurrent passed. Photoelectrochemical degradation was observed with all sensitizers investigated. Sensitization was less efficient and sensitizers were less photostable with nanostructured ZnO compared to nanostructured TiO2. The best performance was confirmed for cis-RuII(dcbpyH22(NCS2 on TiO2. However, it was 7–10 times less stable under other identical conditions on ZnO. Stability is favored by carboxylate anchoring and metal-centred electron transfer. In presence of TiO2, it is enhanced by formation of a stabilizing charge-transfer complex between oxidized Ru dye and back-bonding interfacial Ti3+ states. This is considered to be the main reason for the ongoing use of expensive Ru complexes in combination with TiO2. The local surface chemistry of the nanocrystalline TiO2 turned out to be a crucial factor for sensitizer stability and requires further investigation.

  9. Highly Stable and Active Pt/Nb-TiO2 Carbon-Free Electrocatalyst for Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Shuhui Sun

    2012-01-01

    Full Text Available The current materials used in proton exchange membrane fuel cells (PEMFCs are not sufficiently durable for commercial deployment. One of the major challenges lies in the development of an inexpensive, efficient, and highly durable and active electrocatalyst. Here a new type of carbon-free Pt/Nb-TiO2 electrocatalyst has been reported. Mesoporous Nb-TiO2 hollow spheres were synthesized by the sol-gel method using polystyrene (PS sphere templates. Pt nanoparticles (NPs were then deposited onto mesoporous Nb-TiO2 hollow spheres via a simple wet-chemical route in aqueous solution, without the need for surfactants or potentiostats. The growth densities of Pt NPs on Nb-TiO2 supports could be easily modulated by simply adjusting the experimental parameters. Electrochemical studies of Pt/Nb-TiO2 show much enhanced activity and stability than commercial E-TEK Pt/C catalyst. PtNP/Nb-TiO2 is a promising new cathode catalyst for PEMFC applications.

  10. Growth and self-assembly of BaTiO3 nanocubes for resistive switching memory cells

    International Nuclear Information System (INIS)

    Chu, Dewei; Lin, Xi; Younis, Adnan; Li, Chang Ming; Dang, Feng; Li, Sean

    2014-01-01

    In this work, the self-assembled BaTiO 3 nanocubes based resistive switching memory capacitors are fabricated with hydrothermal and drop-coating approaches. The device exhibits excellent bipolar resistance switching characteristics with ON/OFF ratio of 58–70, better reliability and stability over various polycrystalline BaTiO 3 nanostructures. It is believed that the inter cube junctions is responsible for such a switching behaviour and it can be described by the filament model. The effect of film thickness on switching ratio (ON/OFF) was also investigated in details. - Graphical abstract: This work describes a novel resistive switching memory cell based on self-assembled BaTiO 3 nanocubes. - Highlights: • BaTiO 3 nanocubes were prepared by one step facile hydrothermal method. • Self-assembled BaTiO 3 nanocubes thin films were obtained by drop-coating approach. • The BaTiO 3 nanocubes show excellent resistive switching properties for memory applications

  11. Quantitative GPCR and ion channel transcriptomics in primary alveolar macrophages and macrophage surrogates

    Directory of Open Access Journals (Sweden)

    Groot-Kormelink Paul J

    2012-10-01

    Full Text Available Abstract Background Alveolar macrophages are one of the first lines of defence against invading pathogens and play a central role in modulating both the innate and acquired immune systems. By responding to endogenous stimuli within the lung, alveolar macrophages contribute towards the regulation of the local inflammatory microenvironment, the initiation of wound healing and the pathogenesis of viral and bacterial infections. Despite the availability of protocols for isolating primary alveolar macrophages from the lung these cells remain recalcitrant to expansion in-vitro and therefore surrogate cell types, such as monocyte derived macrophages and phorbol ester-differentiated cell lines (e.g. U937, THP-1, HL60 are frequently used to model macrophage function. Methods The availability of high throughput gene expression technologies for accurate quantification of transcript levels enables the re-evaluation of these surrogate cell types for use as cellular models of the alveolar macrophage. Utilising high-throughput TaqMan arrays and focussing on dynamically regulated families of integral membrane proteins, we explore the similarities and differences in G-protein coupled receptor (GPCR and ion channel expression in alveolar macrophages and their widely used surrogates. Results The complete non-sensory GPCR and ion channel transcriptome is described for primary alveolar macrophages and macrophage surrogates. The expression of numerous GPCRs and ion channels whose expression were hitherto not described in human alveolar macrophages are compared across primary macrophages and commonly used macrophage cell models. Several membrane proteins known to have critical roles in regulating macrophage function, including CXCR6, CCR8 and TRPV4, were found to be highly expressed in macrophages but not expressed in PMA-differentiated surrogates. Conclusions The data described in this report provides insight into the appropriate choice of cell models for

  12. Nanosized TiN-SBR hybrid coating of stainless steel as bipolar plates for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Kumagai, Masanobu; Myung, Seung-Taek; Asaishi, Ryo; Sun, Yang-Kook; Yashiro, Hitoshi

    2008-01-01

    In attempt to improve interfacial electrical conductivity of stainless steel for bipolar plates of polymer electrolyte membrane fuel cells, TiN nanoparticles were electrophoretically deposited on the surface of stainless steel with elastic styrene butadiene rubber (SBR) particles. From transmission electron microscopic observation, it was found that the TiN nanoparticles (ca. 50 nm) surrounded the spherical SBR particles (ca. 300-600 nm), forming agglomerates. They were well adhered on the surface of the type 310S stainless steel. With help of elasticity of SBR, the agglomerates were well fitted into the interfacial gap between gas diffusion layer (GDL) and stainless steel bipolar plate, and the interfacial contact resistance (ICR), simultaneously, was successfully reduced. A single cell using the TiN nanoparticles-coated bipolar plates, consequently, showed comparable cell performance with the graphite employing cell at a current density of 0.5 A cm -2 (12.5 A). Inexpensive TiN nanoparticle-coated type 310S stainless steel bipolar plates would become a possible alternate for the expensive graphite bipolar plates as use in fuel cell applications

  13. Polyoxometalate-modified TiO2 nanotube arrays photoanode materials for enhanced dye-sensitized solar cells

    Science.gov (United States)

    Liu, Ran; Sun, Zhixia; Zhang, Yuzhuo; Xu, Lin; Li, Na

    2017-10-01

    In this work, we prepared for the first time the TiO2 nanotube arrays (TNAs) photoanode with polyoxometalate(POMs)-modified TiO2 electron-transport layer for improving the performance of zinc phthalocyanine(ZnPc)-sensitized solar cells. The as-prepared POMs/TNAs/ZnPc composite photoanode exhibited higher photovoltaic performances than the TNAs/ZnPc photoanode, so that the power conversion efficiency of the solar cell device based on the POMs/TNAs/ZnPc photoanode displayed a notable improvement of 45%. These results indicated that the POMs play a key role in reducing charge recombination in phthalocyanine-sensitized solar cells, together with TiO2 nanotube arrays being helpful for electron transport. The mechanism of the performance improvement was demonstrated by the measurements of electrochemical impedance spectra and open-circuit voltage decay curves. Although the resulting performance is still below that of the state-of-the-art dye-sensitized solar cells, this study presents a new insight into improving the power conversion efficiency of phthalocyanine-sensitized solar cells via polyoxometalate-modified TiO2 nanotube arrays photoanode.

  14. Sealed two-electrode photoelectrochemical cell based on nanocrystalline TiO2 analyzed as a UV sensor

    International Nuclear Information System (INIS)

    Forcade, Fresnel; Gonzalez, Bernardo; Maqueda, Ma. de la Luz; Curbelo, Larisa; Vigil, Elena; Jennings, James R.; Dunn, Halina; Wang, Hongxia; PeteR, Lauri M.

    2008-01-01

    Potentialities as UV sensor of a sealed two-electrode photoelectrochemical cell (PEC) based on nanocrystalline TiO 2 are analyzed. Ultraviolet component of solar light is responsible for a number of skin disorders and diseases. An inexpensive and simple UV sensor would be convenient to measure the UV intensity been exposed to. Nanocrystalline TiO 2 is a rather inexpensive material, innocuous and very stable which is intensively studied at the present moment because of its possible applications in dye-sensitized solar cells, photocatalysis, electrochromics, etc. The method for obtaining the sensor and its structure are described. Different TiO 2 layer structures for the photoelectrode are studied. Important parameters, such as, spectral response, external quantum efficiency, current vs light intensity and current-voltage curve are presented. Results show prospective for the implementation of this type of sensor. (Full text)

  15. Preparation of anatase TiO2 nanoparticles using low hydrothermal temperature for dye-sensitized solar cell

    Science.gov (United States)

    Sofyan, N.; Ridhova, A.; Yuwono, A. H.; Udhiarto, A.

    2018-03-01

    One device being developed as an alternative source of renewable energy by utilizing solar energy source is dye-sensitized solar cells (DSSC). This device works using simple photosynthetic-electrochemical principle in the molecular level. In this device, the inorganic oxide semiconductor of titanium dioxide (TiO2) has a great potential for the absorption of the photon energy from the solar energy source, especially in the form of TiO2 nanoparticle structure. This nanoparticle structure is expected to improve the performance of DSSC because the surface area to weight ratio of this nanostructures is very large. In this study, the synthesis of TiO2 nanoparticle from its precursors has been performed along with the fabrication of the DSSC device. Effort to improve the size of nanocrystalline anatase TiO2 was accomplished by low hydrothermal treatment at various temperatures whereas the crystallinity of the anatase phase in the structure was performed by calcination process. Characterization of the materials was performed using X-ray Diffraction (XRD) and scanning electron microscope (SEM), while the DSSC performance was examined through a high precision current versus voltage (I-V) curve analyzer. The results showed that pure anatase TiO2 nanoparticles could be obtained at low hydrothermal of 100, 125, and 150 °C followed by calcination at 450 °C. The best performance of photocurrent-voltage characteristic was given by TiO2 hydrothermally synthesized at 150 °C with power conversion efficiency (PCE) of 4.40 %, whereas the standard TiO2 nanoparticles has PCE only 4.02 %. This result is very promising in terms low temperature and thus low cost of anatase TiO2 semiconductor preparation for DSSC application.

  16. Improving microstructured TiO{sub 2} photoanodes for dye sensitized solar cells by simple surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Saquib; Birnie, Dunbar P. III [Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, 607 Taylor Road, Piscataway, NJ 08854 (United States); Du Pasquier, Aurelien [Energy Storage Research Group (ESRG), Rutgers, The State University of New Jersey, 671 US Highway 1, North Brunswick, NJ 08902 (United States); Asefa, Tewodros [Department of Chemistry and Chemical Biology and Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, NJ 08854 (United States)

    2011-10-15

    TiCl{sub 4} surface treatment studies of porous electrode structure of TiO{sub 2} aggregates synthesized using an acidic precursor and CTAB as a templating agent are carried out in order to understand and improve upon recombination kinetics in the photonanode film matrix, together with enhancing the intrinsic light scattering. The key beneficial features of the photoanode included high surface roughness, necessary for superior dye adsorption, nanocrystallite aggregates leading to diffuse light scattering within the film matrix, and a hierarchical macro- and mesopore structure allowing good access of electrolyte to the dye, thereby assisting in dye regeneration (enhanced charge transfer). Pre-treatment of the TiO{sub 2} electrodes reduced recombination at the fluorine-doped tin oxide (FTO)/electrolyte interface. The post-treatment study showed enhanced surface roughness through the deposition of a thin overlayer of amorphous TiO{sub 2} on the film structure. This led to a notable improvement in both dye adsorption and inherent light scattering effects by the TiO{sub 2} aggregates, resulting in enhanced energy harvesting. The thin TiO{sub 2} overlayer also acted as a barrier in a core-shell configuration within the porous TiO{sub 2} matrix, and thereby reduced recombination. This allowed the hierarchical macro- and mesoporosity of the film matrix to be utilized more effectively for enhanced charge transfer during dye regeneration. Post-treatment of the aggregated TiO{sub 2} matrix resulted in a 36% enhancement in power conversion efficiency from 4.41% of untreated cells to 6.01%. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Properties of CuInS₂ Nano-Particles on TiO₂ by Spray Pyrolysis for CuInS₂/TiO₂ Composite Solar Cell.

    Science.gov (United States)

    Park, Gye-Choon; Li, Zhen-Yu; Yang, O-Bong

    2017-04-01

    In this letter, for the absorption layer of a CuInS₂/TiO₂ composite solar cell, I–III–VI2 chalcopyrite semiconductor CuInS₂ nano-particles were deposited by using spray pyrolysis method on TiO2 porous film. Their material characteristics including structural and optical properties of CuInS₂ nano-particles on TiO₂ nanorods were analyzed as a function of its composition ratios of Cu:In:S. Crystalline structure, surface morphology and crystalline size were also investigated by X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and High-Resolution TEM (HRTEM), respectively. On the other hand, optical property was characterized by an UV-Visible Spectrophotometer. As a result, it was found that the size of CuInS₂ nano-particles, which was formed at 300±5 °C, was smaller than 16 nm from HRTEM analyses, and it was identified that the CuInS₂ particle size was increased as increasing the heat-treatment temperature and time. However, as the size of CuInS₂ nano-particle becomes smaller, optical absorption edge of ternary compound film tends to move to the blue wavelength band. It turns out that the optical energy-band gap of the compound films was ranging from 1.48 eV to 1.53 eV.

  18. PIIID-formed (Ti, O)/Ti, (Ti, N)/Ti and (Ti, O, N)/Ti coatings on NiTi shape memory alloy for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Sun Tao, E-mail: taosun@hotmail.com.hk [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Institute of Microelectronics, Agency for Science, Technology and Research (A-STAR) (Singapore); Wang Langping, E-mail: aplpwang@hit.edu.cn [State Key Lab of Advanced Welding and Joining, Harbin Institute of Technology (China); Wang Min; Tong Howang [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Lu, William W. [Department of Orthopedics and Traumatology, University of Hong Kong, Sassoon Road (Hong Kong)

    2012-08-01

    (Ti, O)/Ti, (Ti, N)/Ti and (Ti, O, N)/Ti composite coatings were fabricated on NiTi shape memory alloy via plasma immersion ion implantation and deposition (PIIID). Surface morphology of samples was investigated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Cross-sectional morphology indicated that the PIIID-formed coatings were dense and uniform. X-ray diffraction (XRD) was used to characterize the phase composition of samples. X-ray photoelectron spectroscopy (XPS) results showed that the surface of coated NiTi SMA samples was Ni-free. Nanoindentation measurements and pin-on-disc tests were carried out to evaluate mechanical properties and wear resistance of coated NiTi SMA, respectively. For the in vitro biological assessment of the composite coatings in terms of cell morphology and cell viability, osteoblast-like SaOS-2 cells and breast cancer MCF-7 cells were cultured on NiTi SMA samples, respectively. SaOS-2 cells attached and spread better on coated NiTi SMA. Viability of MCF-7 cells showed that the PIIID-formed composite coatings were noncytotoxic and coated samples were more biocompatible than uncoated samples. - Highlights: Black-Right-Pointing-Pointer PIIID-formed coatings were fabricated on NiTi SMA to improve its biocompatibility. Black-Right-Pointing-Pointer Microstructure, mechanical properties and biocompatibility of coatings were investigated. Black-Right-Pointing-Pointer All PIIID-formed composite coatings were noncytotoxic and cytocompatible.

  19. Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium

    Science.gov (United States)

    Shri, D. N. Awang; Tsuchiya, K.; Yamamoto, A.

    2017-09-01

    In recent years there are growing interest in fabrication of bulk nanostructured metals and alloys by using severe plastic deformation (SPD) techniques as new alternative in producing bulk nanocrystalline materials. These techniques allows for processing of bulk, fully dense workpiece with ultrafine grains. Metal undergoes SPD processing in certain techniques such as high pressure torsion (HPT), equal-channel angular pressing (ECAP) or multi-directional forging (MDF) are subjected to extensive hydrostatic pressure that may be used to impart a very high strain to the bulk solid without the introduction of any significant change in overall dimension of the sample. The change in the structure (small grain size and high-volume fraction of grain boundaries) of the material may result in the corrosion behavior different from that of the coarse-grained material. Electrochemical measurements were done to understand the corrosion behavior of TiNi alloys before and after HPT deformation. The experiment was carried out using standard three electrode setup (a sample as working electrode; a platinum wire as a counter electrode and a saturated calomel electrode in saturated KCl as a reference electrode) with the surface area of 26.42 mm2 exposed to the EMEM+10% FBS cell culture medium. The measurements were performed in an incubator with controlled environment at 37 °C and 5% CO2, simulating the cell culture condition. The potential of the specimen was monitored over 1 hour, and the stabilized potential was used as the open-circuit potential (EOCP). Potentiodynamic curves were scanned in the potential range from -0.5 V to 1.5 V relative to the EOCP, at a rate of 0.5 mV/s. The result of OCP-time measurement done in the cell culture medium shows that the OCP of HPT-deformed samples shifts towards to the more positive rather than that of BHPT samples. The OCP of deformed samples were ennobled to more than +70 mV for Ti-50mol%. The shift of OCP towards the nobler direction

  20. Bulky PAH-DNA induced by exposure of a co-culture model of human alveolar macrophages and embryonic epithelial cells to atmospheric particulate pollution

    International Nuclear Information System (INIS)

    Abbas, Imane; Garcon, Guillaume; Billet, Sylvain; Shirali, Pirouz; Andre, Veronique; Le Goff, Jeremie; Sichel, Francois; Roy Saint-Georges, Francoise; Mulliez, Philippe

    2012-01-01

    Because of their deep penetration in human lungs, fine airborne particulate matter were described as mainly responsible for the deleterious effects of exposure to air pollution on health. Organic constituents are adsorbed on particles surface and, after inhalation, some (polycyclic aromatic hydrocarbons, PAHs) can be activated into reactive metabolites and can bind to DNA. The formation of bulky DNA adducts has been researched after exposure of mono-and co-cultures of alveolar macrophages (AM) and human embryonic human lung epithelial (L132), to fine air pollution particulate matter Air samples have been collected with cascade impactor and characterized: size distribution (92.15% 2 /g), inorganic (Fe, AI, Ca, Na, K, Mg, Pb, etc.) and organic compounds (PAHs, etc.). 32 P post-labeling method was applied to detect bulky DNA adducts in AM and L132, in mono-and co-cultures, 72 h after their exposure to atmospheric particles at their Lethals and Effects concentrations or (LC or CE) to 50% (i.e. MA: EC 50 = 74.63 μg/mL and L132: LC-5-0 = 75.36 μg/mL). Exposure to desorbed particles (MA: C1= 61.11 μg/mL and L132 : C2 = 61.71 μg/mL) and B[a]P (1 μM) were included. Bulky PAH-DNA adducts were detected in AM in mono-culture after exposure to total particles (Pt), to B[a]P and desorbed particles (Pd). Whatever the exposure, no DNA adduct was detected in L132 in mono-culture. These results are coherent with the enzymatic activities of cytochrome P450 l Al in AM and L132. Exposure of co-culture to Pt, or Pd induced bulky adducts to DNA in AM but not in L132. Exposure to B[a]P alone has altered the DNA of AM and L132, in co-culture. Exposure to Pt is closer to the environmental conditions, but conferred an exposure to amounts of genotoxic agents compared to studies using organic extracts. The formation of bulky DNA adducts was nevertheless observed in AM exposed to Pt, in mono- or co-culture, indicating that they were competent in terms of metabolic activation of PAHs. The

  1. Uniform TiO2 nanoparticles induce apoptosis in epithelial cell lines in a size-dependent manner.

    Science.gov (United States)

    Sun, Qingqing; Ishii, Takayuki; Kanehira, Koki; Sato, Takeshi; Taniguchi, Akiyoshi

    2017-05-02

    The size of titanium dioxide (TiO 2 ) nanoparticles is a vital parameter that determines their cytotoxicity. However, most reported studies have employed irregular shapes and sizes of TiO 2 nanoparticles, as it is difficult to produce nanoparticles of suitable sizes for research. We produced good model TiO 2 nanoparticles of uniform shape and size for use in studying their cytotoxicity. In this work, spherical, uniform polyethylene glycol-modified TiO 2 (TiO 2 -PEG) nanoparticles of differing sizes (100, 200, and 300 nm) were prepared using the sol-gel method. A size-dependent decrease in cell viability was observed with increasing nanoparticle size. Furthermore, apoptosis was found to be positively associated with nanoparticle size, as evidenced by an increase in caspase-3 activity with increasing nanoparticle size. Larger nanoparticles exhibited higher cellular uptake, suggesting that larger nanoparticles more strongly induce apoptosis. In addition, the cellular uptake of different sizes of nanoparticles was energy dependent, suggesting that there are size-dependent uptake pathways. We found that 100 and 200 nm (but not 300 nm) nanoparticles were taken up via clathrin-mediated endocytosis. These results utilizing uniform nanoparticles suggest that the size-dependent cytotoxicity of nanoparticles involves active cellular uptake, caspase-3 activation, and apoptosis in the epithelial cell line (NCI-H292). These findings will hopefully aid in the future design and safe use of nanoparticles.

  2. A mixture of anatase and rutile TiO2 nanoparticles induces histamine secretion in mast cells

    Directory of Open Access Journals (Sweden)

    Chen Eric Y

    2012-01-01

    Full Text Available Abstract Background Histamine released from mast cells, through complex interactions involving the binding of IgE to FcεRI receptors and the subsequent intracellular Ca2+ signaling, can mediate many allergic/inflammatory responses. The possibility of titanium dioxide nanoparticles (TiO2 NPs, a nanomaterial pervasively used in nanotechnology and pharmaceutical industries, to directly induce histamine secretion without prior allergen sensitization has remained uncertain. Results TiO2 NP exposure increased both histamine secretion and cytosolic Ca2+ concentration ([Ca2+]C in a dose dependent manner in rat RBL-2H3 mast cells. The increase in intracellular Ca2+ levels resulted primarily from an extracellular Ca2+ influx via membrane L-type Ca2+ channels. Unspecific Ca2+ entry via TiO2 NP-instigated membrane disruption was demonstrated with the intracellular leakage of a fluorescent calcein dye. Oxidative stress induced by TiO2 NPs also contributed to cytosolic Ca2+ signaling. The PLC-IP3-IP3 receptor pathways and endoplasmic reticulum (ER were responsible for the sustained elevation of [Ca2+]C and histamine secretion. Conclusion Our data suggests that systemic circulation of NPs may prompt histamine release at different locales causing abnormal inflammatory diseases. This study provides a novel mechanistic link between environmental TiO2 NP exposure and allergen-independent histamine release that can exacerbate manifestations of multiple allergic responses.

  3. Morphology control for highly efficient organic–inorganic bulk heterojunction solar cell based on Ti-alkoxide

    International Nuclear Information System (INIS)

    Kato, Takehito; Hagiwara, Naoki; Suzuki, Eiji; Nasu, Yuki; Izawa, Satoru; Tanaka, Kouichi; Kato, Ariyuki

    2016-01-01

    The number of publications concerned with typical bulk-heterojunction solar cells that use fullerene derivatives and inorganic materials as electron acceptors has grown very rapidly. In this work, we focus on Ti-alkoxides as electron acceptors in the photoactive layers of fullerene-free bulk-heterojunction solar cells. We show that it is possible to control the morphology by adjusting the molecular structure and size of the Ti-alkoxides. The short-circuit current density (J_s_c) increased to 191 μA/cm"2 from 25 μA/cm"2 with a maximum, when the phase-separation structure was continuously formed to within about 20 nm below the exciton diffusion length by using either titanium(IV) ethoxide or isopropoxide as an electron acceptor. Within a thickness of 30 nm, the photoactive layer is not influenced by the electron transfer ability; thus, we demonstrate that the charge-separation efficiency is equivalent to that of a fullerene system. - Highlights: • An organic–inorganic bulk-heterojunction photoactive layer was used. • Electron donor was a semiconducting polymer and electron acceptor was Ti-alkoxide. • Demonstration of morphology control by Ti-alkoxide molecules. • Determination of Jsc value by the phase-separation structure in an ultra-thin film. • Charge-separation efficiency of Ti-alkoxide system equivalent to fullerene system.

  4. Enhancement of Dye-Sensitized Solar Cells Efficiency Using Mixed-Phase TiO2 Nanoparticles as Photoanode

    Directory of Open Access Journals (Sweden)

    Yi-Hua Fan

    2017-01-01

    Full Text Available Dye-sensitized solar cell (DSSC is a potential candidate to replace conventional silicon-based solar cells because of high efficiency, cheap cost, and lower energy consumption in comparison with silicon chip manufacture. In this report, mixed-phase (anatase and rutile nanoparticles TiO2 photoanode was synthesized to investigate material characteristics, carriers transport, and photovoltaic performance for future DSSC application. Field-emission scanning electron microscope (SEM, X-ray diffraction (XRD, photoluminescence (PL, and UV-visible spectroscopy were used to characterize mixed TiO2 particles. Subsequently, various mixed-phase TiO2 anodes in DSSC devices were measured by electrical impedance spectra (EIS and energy efficiency conversion. The overall energy conversion efficiency of DSSC chip was improved as a result of the increase of rutile phase of TiO2 (14% in anatase matrix. Synergistic effects including TiO2 crystallization, reduction of defect density level in energy band, longer lifetime of photoexcited electrons, and lower resistance of electron pathway all contributed to high efficiency of light energy conversion.

  5. Electron Beam Evaporated TiO2 Layer for High Efficiency Planar Perovskite Solar Cells on Flexible Polyethylene Terephthalate Substrates

    KAUST Repository

    Qiu, Weiming

    2015-09-30

    The TiO2 layer made by electron beam (e-beam) induced evaporation is demonstrated as electron transport layer (ETL) in high efficiency planar junction perovskite solar cells. The temperature of the substrate and the thickness of the TiO2 layer can be easily controlled with this e-beam induced evaporation method, which enables the usage of different types of substrates. Here, Perovskite solar cells based on CH3NH3PbI3-xClx achieve power conversion efficiencies of 14.6% on glass and 13.5% on flexible plastic substrates. The relationship between the TiO2 layer thickness and the perovskite morphology is studied with scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS). Our results indicate that pinholes in thin TiO2 layer lead to pinholes in the perovskite layer. By optimizing the TiO2 thickness, perovskite layers with substantially increased surface coverage and reduced pinhole areas are fabricated, increasing overall device performance.

  6. Investigation of physical properties and cell performance of Nafion/TiO{sub 2} nanocomposite membranes for high temperature PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Amjadi, M.; Peighambardoust, S.J. [School of Chemical Engineering, Iran University of Science and Technology, Tehran (Iran); Rowshanzamir, S. [School of Chemical Engineering, Iran University of Science and Technology, Tehran (Iran); Fuel Cell Research Laboratory, Green Research Centre, Iran University of Science and Technology, Tehran (Iran); Hosseini, M.G. [Electrochemistry Research Laboratory, Physical Chemistry Department, Chemistry Faculty, Tabriz University, Tabriz (Iran); Eikani, M.H. [Department of Chemical Industries, Iranian Research Organization for Science and Technology (IROST), Tehran (Iran)

    2010-09-15

    Synthesis and characterization of Nafion/TiO{sub 2} membranes for proton exchange membrane fuel cell (PEMFC) operating at high temperatures were investigated in this study. Nafion/TiO{sub 2} nanocomposite membranes have been prepared by in-situ sol-gel and casting methods. In the sol-gel method, preformed Nafion membranes were soaked in tetrabutylortotitanate (TBT) and methanol solution. In order to compare synthesis methods, a Nafion/TiO{sub 2} composite membrane was fabricated with 3 wt.% of TiO{sub 2} particles by the solution casting method. The structures of membranes were investigated by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Analysis (EDXA). Also, water uptake and proton conductivity of modified membranes were measured. Furthermore, the membranes were tested in a real PEMFC. X-Ray spectra of the composite membranes indicate the presence of TiO{sub 2} in the modified membranes. In case of the same doping level, sol-gel method produces more uniform distribution of Ti particles in Nafion/TiO{sub 2} composite membrane than the ones produced by casting method. Water uptake of Nafion/TiO{sub 2} membrane with 3 wt.% of doping level was found to be 51% higher than that of the pure Nafion membrane. EIS measurements showed that the conductivity of modified membranes decreases with increasing the amount of doped TiO{sub 2}. Finally, the membrane electrode assembly (MEA) prepared from Nafion/Titania nanocomposite membrane shows the highest PEMFC performance in terms of voltage vs. current density (V-I) at high temperature (110 C) which is the main goal of this study. (author)

  7. Performance improvement of CdS quantum dots sensitized TiO{sub 2} solar cells by introducing a dense TiO{sub 2} blocking layer

    Energy Technology Data Exchange (ETDEWEB)

    Tachibana, Yasuhiro; Umekita, Kazuya; Otsuka, Yasuhide; Kuwabata, Susumu [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamada-oka, Suita, Osaka 565-0871 (Japan)], E-mail: y.tachibana@chem.eng.osaka-u.ac.jp

    2008-05-21

    A dense TiO{sub 2} electron blocking layer was introduced on a conducting glass in CdS quantum dots sensitized solar cells to investigate electron leakage into the electrolyte. A ferricyanide/ferrocyanide redox couple was employed, as a model electrolyte, possessing a high standard rate constant. The analysis of the I-V characteristics, using a one-diode model, revealed that an increase in this layer, up to 50 nm, significantly suppresses the electron leakage, enhancing the shunt resistance by a factor of 200. An energy conversion efficiency of 1.0% was attained on account of the improved open circuit voltage and fill factor. (fast track communication)

  8. Enhanced Power Conversion Efficiency of Perovskite Solar Cells with an Up-Conversion Material of Er3+-Yb3+-Li+ Tri-doped TiO2.

    Science.gov (United States)

    Zhang, Zhenlong; Qin, Jianqiang; Shi, Wenjia; Liu, Yanyan; Zhang, Yan; Liu, Yuefeng; Gao, Huiping; Mao, Yanli

    2018-05-11

    In this paper, Er 3+ -Yb 3+ -Li + tri-doped TiO 2 (UC-TiO 2 ) was prepared by an addition of Li + to Er 3+ -Yb 3+ co-doped TiO 2 . The UC-TiO 2 presented an enhanced up-conversion emission compared with Er 3+ -Yb 3+ co-doped TiO 2 . The UC-TiO 2 was applied to the perovskite solar cells. The power conversion efficiency (PCE) of the solar cells without UC-TiO 2 was 14.0%, while the PCE of the solar cells with UC-TiO 2 was increased to 16.5%, which presented an increase of 19%. The results suggested that UC-TiO 2 is an effective up-conversion material. And this study provided a route to expand the spectral absorption of perovskite solar cells from visible light to near-infrared using up-conversion materials.

  9. Formation of double-layered TiO2 structures with selectively-positioned molecular dyes for efficient flexible dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Kim, Eun Yi; Yu, Sora; Moon, Jeong Hoon; Yoo, Seon Mi; Kim, Chulhee; Kim, Hwan Kyu; Lee, Wan In

    2013-01-01

    Graphical abstract: A novel flexible tandem dye-sensitized solar cell, selectively loading different dyes in discrete layers, was successfully formed on a plastic substrate by transferring the high-temperature-processed N719/TiO 2 over an organic dye-adsorbed TiO 2 film by a typical compression process at room temperature. -- Highlights: • A novel flexible dye-sensitized solar cell, selectively loading two different dyes in discrete layers, was successfully formed on a plastic substrate. • η of the flexible tandem cell obtained by transferring the high-temperature-processed TiO 2 layer was enhanced from 2.91% to 6.86%. • Interface control between two TiO 2 layers is crucial for the efficient transport of photo-injected electrons from the top to bottom TiO 2 layer. -- Abstract: To fabricate flexible dye-sensitized solar cells (DSCs) utilizing full solar spectrum, the double-layered TiO 2 films, selectively loading two different dyes in discrete layers, were formed on a plastic substrate by transferring the high-temperature-processed N719/TiO 2 over an organic dye (TA-St-CA)-sensitized TiO 2 film by a typical compression process at room temperature. It was found that interface control between two TiO 2 layers is crucial for the efficient transport of photo-injected electrons from the N719/TiO 2 to the TA-St-CA/TiO 2 layer. Electron impedance spectra (EIS) and transient photoelectron spectroscopic analyses exhibited that introduction of a thin interfacial TiO 2 layer between the two TiO 2 layers remarkably decreased the resistance at the interface, while increasing the electron diffusion constant (D e ) by ∼10 times. As a result, the photovoltaic conversion efficiency (η) of the flexible tandem DSC was 6.64%, whereas that of the flexible cell derived from the single TA-St-CA/TiO 2 layer was only 2.98%. Another organic dye (HC-acid), absorbing a short wavelength region of solar spectrum, was also applied to fabricate flexible tandem DSC. The η of the cell

  10. Influence of TiO{sub 2} nanoparticles on cellular antioxidant defense and its involvement in genotoxicity in HepG2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Petkovic, Jana; Zegura, Bojana; Filipic, Metka, E-mail: metka.filipic@nib.si [Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, SI-1000 Ljubljana (Slovenia)

    2011-07-06

    We investigated the effects of two types of TiO{sub 2} nanoparticles (<25 nm anatase, TiO{sub 2}-An; <100 nm rutile, TiO{sub 2}-Ru) on cellular antioxidant defense in HepG2 cells. We previously showed that in HepG2 cells, TiO{sub 2} nanoparticles are not toxic, although they induce oxidative DNA damage, production of intracellular reactive oxygen species, and up-regulation of mRNA expression of DNA-damage-responsive genes (p53, p21, gadd45{alpha} and mdm2). In the present study, we measured changes in mRNA expression of several antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase, nitric oxide synthase, glutathione reductase and glutamate-cysteine ligase. As reduced glutathione has a central role in cellular antioxidant defense, we determined the effects of TiO{sub 2} nanoparticles on changes in the intracellular glutathione content. To confirm a role for glutathione in protection against TiO{sub 2}-nanoparticle-induced DNA damage, we compared the extent of TiO{sub 2}-nanoparticle-induced DNA damage in HepG2 cells that were glutathione depleted with buthionine-(S,R)-sulfoximine pretreatment and in nonglutathione-depleted cells. Our data show that both types of TiO{sub 2} nanoparticles up-regulate mRNA expression of oxidative-stress-related genes, with TiO{sub 2}-Ru being a stronger inducer than TiO{sub 2}-An. Both types of TiO{sub 2} nanoparticles also induce dose-dependent increases in intracellular glutathione levels, and in glutathione-depleted cells, TiO{sub 2}-nanoparticle-induced DNA damage was significantly greater than in nonglutathione-depleted cells. Interestingly, the glutathione content and the extent of DNA damage were significantly higher in TiO{sub 2}-An- than TiO{sub 2}-Ru-exposed cells. Thus, we show that TiO{sub 2} nanoparticles cause activation of cellular antioxidant processes, and that intracellular glutathione has a critical role in defense against this TiO{sub 2}-nanoparticle-induced DNA damage.

  11. Fabrication of novel Ag−TiO_2 nanobelts as a photoanode for enhanced photovoltage performance in dye sensitized solar cells

    International Nuclear Information System (INIS)

    Wang, Yang; Li, Zhen; Cao, Ya; Li, Fei; Zhao, Wen; Liu, Xueqin; Yang, Jianbo

    2016-01-01

    TiO_2 nanobelts (TiO_2NBs) were successfully prepared using a solvothermal route via Ti foil as substrate in large scales. The morphology evolution process and formation mechanism of the as-obtained products were investigated in detail. On the basis of this novel structure, chemical sensitive Ag modified TiO_2NBs nanocomposites (Ag−TiO_2NBs) were fabricated. It was found that Ag−TiO_2NBs exhibit strong light absorption and efficient electron transport. According to Mott-Schottky analysis, Ag−TiO_2NBs show less surface trapping sites compared with TiO_2NBs. The Ag−TiO_2NBs photoanode fabricated in 0.01 M AgNO_3 demonstrates the best performance with a short-circuit current of 11.9 mA cm"−"2 corresponding to a photoelectric conversion efficiency of 4.89%, which is higher than that of pure TiO_2NBs based solar cell by 60%. - Graphical abstract: J-V curves of DSSCs based on TiO_2NPs, TiO_2NBs and Ag−TiO_2NBs—X under AM 1.5 conditions (100 mW cm"−"2). Ag−TiO_2NBs nanocomposites were prepared via a simple and effective method. Owing to strong light absorption and efficient electron transport, Ag−TiO_2NBs—0.01 M shows a PCE of 4.89% when prepared as a photoanode in DSSCs. - Highlights: • A facile route was adopted to construct well-dispersed Ag nanoparticles on TiO_2 nanobelts (Ag—TiO_2NBs). • Structure and photoelectrochemical properties of Ag—TiO_2NBs were studied. • Ag nanoparticles were found to modify the defects of TiO_2NBs. • Enhanced photovoltaic property of Ag—TiO_2NBs, compared to TiO_2NBs.

  12. Fabrication of novel Ag−TiO{sub 2} nanobelts as a photoanode for enhanced photovoltage performance in dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yang [Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Li, Zhen, E-mail: zhenli@cug.edu.cn [Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Cao, Ya; Li, Fei; Zhao, Wen; Liu, Xueqin; Yang, Jianbo [Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China)

    2016-08-25

    TiO{sub 2} nanobelts (TiO{sub 2}NBs) were successfully prepared using a solvothermal route via Ti foil as substrate in large scales. The morphology evolution process and formation mechanism of the as-obtained products were investigated in detail. On the basis of this novel structure, chemical sensitive Ag modified TiO{sub 2}NBs nanocomposites (Ag−TiO{sub 2}NBs) were fabricated. It was found that Ag−TiO{sub 2}NBs exhibit strong light absorption and efficient electron transport. According to Mott-Schottky analysis, Ag−TiO{sub 2}NBs show less surface trapping sites compared with TiO{sub 2}NBs. The Ag−TiO{sub 2}NBs photoanode fabricated in 0.01 M AgNO{sub 3} demonstrates the best performance with a short-circuit current of 11.9 mA cm{sup −2} corresponding to a photoelectric conversion efficiency of 4.89%, which is higher than that of pure TiO{sub 2}NBs based solar cell by 60%. - Graphical abstract: J-V curves of DSSCs based on TiO{sub 2}NPs, TiO{sub 2}NBs and Ag−TiO{sub 2}NBs—X under AM 1.5 conditions (100 mW cm{sup −2}). Ag−TiO{sub 2}NBs nanocomposites were prepared via a simple and effective method. Owing to strong light absorption and efficient electron transport, Ag−TiO{sub 2}NBs—0.01 M shows a PCE of 4.89% when prepared as a photoanode in DSSCs. - Highlights: • A facile route was adopted to construct well-dispersed Ag nanoparticles on TiO{sub 2} nanobelts (Ag—TiO{sub 2}NBs). • Structure and photoelectrochemical properties of Ag—TiO{sub 2}NBs were studied. • Ag nanoparticles were found to modify the defects of TiO{sub 2}NBs. • Enhanced photovoltaic property of Ag—TiO{sub 2}NBs, compared to TiO{sub 2}NBs.

  13. Plasma-assisted atomic layer deposition of TiO2 compact layers for flexible mesostructured perovskite solar cells

    NARCIS (Netherlands)

    Zardetto, V.; Di Giacomo, F.; Lucarelli, G.; Kessels, W.M.M.; Brown, T.M.; Creatore, M.

    2017-01-01

    In mesostructured perovskite solar cell devices, charge recombination processes at the interface between the transparent conductive oxide, perovskite and hole transport layer are suppressed by depositing an efficient compact TiO2 blocking layer. In this contribution we investigate the role of the

  14. Multifunctional Inverse Opal-Like TiO2 Electron Transport Layer for Efficient Hybrid Perovskite Solar Cells.

    Science.gov (United States)

    Chen, Xiao; Yang, Shuang; Zheng, Yi Chu; Chen, Ying; Hou, Yu; Yang, Xiao Hua; Yang, Hua Gui

    2015-09-01

    A novel multifunctional inverse opal-like TiO 2 electron transport layer (IOT-ETL) is designed to replace the traditional compact layer and mesoporous scaffold layer in perovskite solar cells (PSCs). Improved light harvesting efficiency and charge transporting performance in IOT-ETL based PSCs yield high power conversion efficiency of 13.11%.

  15. Biochemical Effects of six Ti02 and four Ce02 Nanomaterials in HepG2 cells

    Science.gov (United States)

    Abstract The potential mammalian hepatotoxicity of nanomaterials were explored in dose-response and structure-activity studies with human hepatic HepG2 cells exposed to between 10 and 1000 ug/ml of six different TiO2 and four CeO2 nanomaterials for 3 days. Var...

  16. CdSxSe1−x alloyed quantum dots-sensitized solar cells based on different architectures of anodic oxidation TiO2 film

    International Nuclear Information System (INIS)

    Li, Zhen; Yu, Libo; Liu, Yingbo; Sun, Shuqing

    2014-01-01

    Nanostructured TiO 2 translucent films with different architectures including TiO 2 nanotube (NT), TiO 2 nanowire (NW), and TiO 2 nanowire/nanotube (NW/NT) have been produced by second electrochemical oxidization of TiO 2 NT with diameter around 90–110 nm via modulation of applied voltage. These TiO 2 architectures are sensitized with CdS x Se 1−x alloyed quantum dots (QDs) in sizes of around 3–5 nm aiming to tune the response of the photoelectrochemical properties in the visible region. One-step hydrothermal method facilitates the deposition of CdS x Se 1−x QDs onto TiO 2 films. These CdS x Se 1−x QDs exhibit a tunable range of light absorption with changing the feed molar ratio of S:Se in precursor solution, and inject electrons into TiO 2 films upon excitation with visible light, enabling their application as photosensitizers in sensitized solar cells. Power conversion efficiency (PCE) of 2.00, 1.72, and 1.06 % are achieved with CdS x Se 1−x (obtained with S:Se = 0:4) alloyed QDs sensitized solar cells based on TiO 2 NW/NT, TiO 2 NW, and TiO 2 NT architectures, respectively. The significant enhancement of power conversion efficiency obtained with the CdS x Se 1−x /TiO 2 NW/NT solar cell can be attributed to the extended absorption of light region tuned by CdS x Se 1−x alloyed QDs and enlarged deposition of QDs and efficient electrons transport provided by TiO 2 NW/NT architecture

  17. Improved performance of dye-sensitized solar cells: An TiO{sub 2}-nano-SiO{sub 2} hybrid photoanode with post-treatment of TiCl{sub 4} aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Liu Ling; Niu Haihong; Zhang Shouwei; Wan Lei [School of Electrical Engineering and Automation, Hefei University of Technology (HFUT), School of Chemical Engineering, HFUT, Hefei 230009 (China); Miao Shiding, E-mail: miaosd@iccas.ac.cn [School of Electrical Engineering and Automation, Hefei University of Technology (HFUT), School of Chemical Engineering, HFUT, Hefei 230009 (China); Xu Jinzhang, E-mail: xujz@hfut.edu.cn [School of Electrical Engineering and Automation, Hefei University of Technology (HFUT), School of Chemical Engineering, HFUT, Hefei 230009 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer A TiO{sub 2}-nano-SiO{sub 2} hybrid film was prepared by depositing a paste of TiO{sub 2} (P{sub 25}) incorporated with SiO{sub 2}. Black-Right-Pointing-Pointer The optimal concentration of TiCl{sub 4} solution was found to be 75 mM for the post-treatment. Black-Right-Pointing-Pointer A photoelectron conversion efficiency of 6.39% was achieved for the prepared dye-sensitized solar cells (DSSCs). Black-Right-Pointing-Pointer SiO{sub 2} gives a significant improvement in the performance of the DSSCs. - Abstract: A TiO{sub 2}-nano-SiO{sub 2} hybrid film was prepared on a conductive F-doped tin oxide (FTO) substrate by depositing a mixture paste of TiO{sub 2} (P{sub 25}) and nano-sized SiO{sub 2} particles. The hybrid film was further treated by a titanium tetrachloride (TiCl{sub 4}) aqueous solution with different concentrations before it was assembled as a photoanode in dye sensitized solar cells (DSSCs). We studied the performance of DSSCs by using the dye molecule of cis-bis(isothiocy-anato)-bis-(2,2 Prime -bipyridyl-4,4 Prime -dicarboxylato) -ruthenium(II) bis-tetrabutylammonium (N719) as sensitizer. Results suggested that the post-treatment using TiCl{sub 4} could enhance the dye adsorption. The thin TiO{sub 2} layer hydrolyzed from TiCl{sub 4} could fill gaps between nanoparticles in the composite film, leading to a better electron transport than non-treated films, and improve the light harvesting efficiency. The optimal concentration was found to be 75 mM for the post-treatment of TiO{sub 2}-SiO{sub 2} hybrid film by TiCl{sub 4} solution. A photoelectron conversion efficiency of 6.39% was achieved in the back-side illuminated dye-sensitized solar cells, which is {approx}105% higher than the basic efficiency of the bare TiO{sub 2} sensitized sample. TiO{sub 2}-nano-SiO{sub 2} hybrid photoanode was prepared by incorporation of nano-sized SiO{sub 2} in the TiO{sub 2} film. The introduced SiO{sub 2} as a wide band

  18. Leukotriene B4 receptors on guinea pig alveolar eosinophils

    International Nuclear Information System (INIS)

    Maghni, K.; de Brum-Fernandes, A.J.; Foeldes-Filep, E.G.; Gaudry, M.; Borgeat, P.; Sirois, P.

    1991-01-01

    The existence of receptors for LTB4 on highly purified guinea pig alveolar eosinophils was investigated. Massive infiltration of eosinophils in alveolar spaces was induced in guinea pigs by i.v. injections of Sephadex beads G50 (16 mg/kg). Alveolar eosinophils (50 x 10(6) cells) were purified to approximately 98% by Percoll continuous density gradient centrifugation. The binding studies indicated that alveolar eosinophils bind LTB4 in a saturable, reversible and specific manner. Scatchard analysis indicated the existence of high-affinity binding sites (Kd1 = 1.00 ± 0.22 nM; Bmax1 = 966 ± 266 sites/cell) and low-affinity binding sites (Kd2 = 62.5 ± 8.9 nM; Bmax2 = 5557 ± 757 sites/cell). The metabolism of LTB4 by alveolar eosinophils in binding conditions was assessed by RP-HPLC and no significant degradation of [3H]LTB4 was observed. LTB4 dose-dependently stimulated eosinophil migration in both chemokinesis and chemotaxis assays with an EC50 value of 1.30 ± 0.14 and 18.14 ± 1.57 nM, respectively. LTB4 caused a dose-dependent increase in the production of superoxide anion with an apparent EC50 value of 50 x 10(-9) M in the authors experimental conditions. LTB4 also induced a dose-dependent increase in the generation of TxA2 with an EC50 value of 46.2 x 10(-9) M. Taken together, their results demonstrated that guinea pig alveolar eosinophils express two classes of specific receptors for LTB4. The high-affinity binding sites seem associated to chemokinesis and chemotaxis whereas the low-affinity binding sites seem associated to superoxide anion production and generation of TxA2. The existence of LTB4 receptors in eosinophils could explain the presence of these cells in hypersensitivity reactions

  19. Dye-sensitized solar cells based on anatase TiO2/multi-walled carbon nanotubes composite nanofibers photoanode

    International Nuclear Information System (INIS)

    Du, Pingfan; Song, Lixin; Xiong, Jie; Li, Ni; Wang, Lijun; Xi, Zhenqiang; Wang, Naiyan; Gao, Linhui; Zhu, Hongliang

    2013-01-01

    Highlights: ► TiO 2 /multi-walled carbon nanotubes (MWCNTs) hybrid nanofibers are prepared via electrospinning. ► Dye-sensitized solar cells (DSSCs) are assembled using TiO 2 /MWCNTs nanofibers film as photoanode. ► Energy conversion efficiency of DSSCs is greatly dependent on the content of MWCNTs. ► Moderate MWCNTs incorporation can substantially enhance the performance of DSSCs. - Abstract: Anatase TiO 2 /multi-walled carbon nanotubes (TiO 2 /MWCNTs) hybrid nanofibers (NFs) film was prepared via a facile electrospinning method. Dye-sensitized solar cells (DSSCs) based on TiO 2 /MWCNTs composite NFs photoanodes with different contents of MWCNTs (0, 0.1, 0.3, 0.5, 1 wt.%) were assembled using N719 dye as sensitizer. Field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), and Raman spectrometer were used to characterize the TiO 2 /MWCNTs electrode films. The photocurrent–voltage (I–V) characteristic, incident photo-to-current conversion efficiency (IPCE) spectrum, and electrochemical impedance spectroscopy (EIS) measurements were carried out to evaluate the photoelectric properties of the DSSCs. The results reveal that the energy conversion efficiency is greatly dependent on the content of MWCNTs in the composite NFs film, and a moderate incorporation of MWCNTs can substantially enhance the performance of DSSCs. When the electrode contains 0.3 wt.% MWCNTs, the corresponding solar cell yield the highest efficiency of 5.63%. This efficiency value is approximately 26% larger than that of the unmodified counterpart.

  20. The biocompatibility of titanium cardiovascular devices seeded with autologous blood-derived endothelial progenitor cells: EPC-seeded antithrombotic Ti implants.

    Science.gov (United States)

    Achneck, Hardean E; Jamiolkowski, Ryan M; Jantzen, Alexandra E; Haseltine, Justin M; Lane, Whitney O; Huang, Jessica K; Galinat, Lauren J; Serpe, Michael J; Lin, Fu-Hsiung; Li, Madison; Parikh, Amar; Ma, Liqiao; Chen, Tao; Sileshi, Bantayehu; Milano, Carmelo A; Wallace, Charles S; Stabler, Thomas V; Allen, Jason D; Truskey, George A; Lawson, Jeffrey H

    2011-01-01

    Implantable and extracorporeal cardiovascular devices are commonly made from titanium (Ti) (e.g. Ti-coated Nitinol stents and mechanical circulatory assist devices). Endothelializing the blood-contacting Ti surfaces of these devices would provide them with an antithrombogenic coating that mimics the native lining of blood vessels and the heart. We evaluated the viability and adherence of peripheral blood-derived porcine endothelial progenitor cells (EPCs), seeded onto thin Ti layers on glass slides under static conditions and after exposure to fluid shear stresses. EPCs attached and grew to confluence on Ti in serum-free medium, without preadsorption of proteins. After attachment to Ti for 15 min, less than 5% of the cells detached at a shear stress of 100 dyne / cm(2). Confluent monolayers of EPCs on smooth Ti surfaces (Rq of 10 nm), exposed to 15 or 100 dyne/cm(2) for 48 h, aligned and elongated in the direction of flow and produced nitric oxide dependent on the level of shear stress. EPC-coated Ti surfaces had dramatically reduced platelet adhesion when compared to uncoated Ti surfaces. These results indicate that peripheral blood-derived EPCs adhere and function normally on Ti surfaces. Therefore EPCs may be used to seed cardiovascular devices prior to implantation to ameliorate platelet activation and thrombus formation. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Effect of nano/micro-Ag compound particles on the bio-corrosion, antibacterial properties and cell biocompatibility of Ti-Ag alloys.

    Science.gov (United States)

    Chen, Mian; Yang, Lei; Zhang, Lan; Han, Yong; Lu, Zheng; Qin, Gaowu; Zhang, Erlin

    2017-06-01

    In this research, Ti-Ag alloys were prepared by powder metallurgy, casting and heat treatment method in order to investigate the effect of Ag compound particles on the bio-corrosion, the antibacterial property and the cell biocompatibility. Ti-Ag alloys with different sizes of Ag or Ag-compounds particles were successfully prepared: small amount of submicro-scale (100nm) Ti 2 Ag precipitates with solid solution state of Ag, large amount of nano-scale (20-30nm) Ti 2 Ag precipitates with small amount of solid solution state of Ag and micro-scale lamellar Ti 2 Ag phases, and complete solid solution state of Ag. The mechanical tests indicated that both nano/micro-scale Ti 2 Ag phases had a strong dispersion strengthening ability and Ag had a high solid solution strengthening ability. Electrochemical results shown the Ag content and the size of Ag particles had a limited influence on the bio-corrosion resistance although nano-scale Ti 2 Ag precipitates slightly improved corrosion resistance. It was demonstrated that the nano Ag compounds precipitates have a significant influence on the antibacterial properties of Ti-Ag alloys but no effect on the cell biocompatibility. It was thought that both Ag ions release and Ti 2 Ag precipitates contributed to the antibacterial ability, in which nano-scale and homogeneously distributed Ti 2 Ag phases would play a key role in antibacterial process. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Effect of porcine reproductive and respiratory syndrome virus (PRRSV) on alveolar lung macrophage survival and function

    DEFF Research Database (Denmark)

    Oleksiewicz, Martin B.; Nielsen, Jens

    1999-01-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) recently emerged as an important cause of reproductive disorders and pneumonia in domestic pigs throughout the world. Acute cytocidal replication of PRRSV in alveolar lung macrophages causes the acute pneumonia; however, it remains largely...... infection in this system. In short, in our minimal system containing only a single cell type, phagocytosis-suppressive effects of PRRSV infection were detected, that acted at the culture level by reducing the total number of alveolar lung macrophages....

  3. Laser surface treatment of polyamide and NiTi alloy and the effects on mesenchymal stem cell response

    Science.gov (United States)

    Waugh, D. G.; Lawrence, J.; Shukla, P.; Chan, C.; Hussain, I.; Man, H. C.; Smith, G. C.

    2015-07-01

    Mesenchymal stem cells (MSCs) are known to play important roles in development, post-natal growth, repair, and regeneration of mesenchymal tissues. What is more, surface treatments are widely reported to affect the biomimetic nature of materials. This paper will detail, discuss and compare laser surface treatment of polyamide (Polyamide 6,6), using a 60 W CO2 laser, and NiTi alloy, using a 100 W fiber laser, and the effects of these treatments on mesenchymal stem cell response. The surface morphology and composition of the polyamide and NiTi alloy were studied by scanning electron microscopy (SEM) and X-ray photoemission spectroscopy (XPS), respectively. MSC cell morphology cell counting and viability measurements were done by employing a haemocytometer and MTT colorimetric assay. The success of enhanced adhesion and spreading of the MSCs on each of the laser surface treated samples, when compared to as-received samples, is evidenced in this work.

  4. Low temperature grown ZnO@TiO{sub 2} core shell nanorod arrays for dye sensitized solar cell application

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Gregory Kia Liang [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research), 3 Research Link, 117602 Singapore (Singapore); Le, Hong Quang, E-mail: lehq@imre.a-star.edu.sg [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research), 3 Research Link, 117602 Singapore (Singapore); Huang, Tang Jiao; Hui, Benjamin Tan Tiong [Department of Materials Science and Engineering (DMSE), Faculty of Engineering National University of Singapore (NUS) BLK E3A, #04-10, 7 Engineering Drive 1, Singapore 117574 (Singapore)

    2014-06-01

    High aspect ratio ZnO nanorod arrays were synthesized on fluorine-doped tin oxide glasses via a low temperature solution method. By adjusting the growth condition and adding polyethylenimine, ZnO nanorod arrays with tunable length were successfully achieved. The ZnO@TiO{sub 2} core shells structures were realized by a fast growth method of immersion into a (NH{sub 4}){sub 2}·TiF{sub 6} solution. Transmission electron microscopy, X-ray Diffraction and energy dispersive X-ray measurements all confirmed the existence of a titania shell uniformly covering the ZnO nanorod's surface. Results of solar cell testing showed that addition of a TiO{sub 2} shell to the ZnO nanorod significantly increased short circuit current (from 4.2 to 5.2 mA/cm{sup 2}), open circuit voltage (from 0.6 V to 0.8 V) and fill factor (from 42.8% to 73.02%). The overall cell efficiency jumped from 1.1% for bare ZnO nanorod to 3.03% for a ZnO@TiO{sub 2} core shell structured solar cell with a 18–22 nm shell thickness, a nearly threefold increase. - Graphical abstract: The synthesis process of coating TiO{sub 2} shell onto ZnO nanorod core is shown schematically. A thin, uniform, and conformal shell had been grown on the surface of the ZnO core after immersing in the (NH{sub 4}){sub 2}·TiF{sub 6} solution for 5–15 min. - Highlights: • ZnO@TiO{sub 2} core shell nanorod has been grown on FTO substrate using low temperature solution method. • TEM, XRD, EDX results confirmed the existing of titana shell, uniformly covered rod's surface. • TiO{sub 2} shell suppressed recombination, demonstrated significant enhancement in cell's efficiency. • Core shell DSSC's efficiency achieved as high as 3.03%, 3 times higher than that of ZnO nanorods.

  5. Preparation of anatase TiO{sub 2} thin film by low temperature annealing as an electron transport layer in inverted polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Hongche [Department of Chemical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Oh, Seong-Geun, E-mail: seongoh@hanyang.ac.kr [Department of Chemical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Im, Seung Soon, E-mail: imss007@hanyang.ac.kr [Department of Organic and Nano Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-04-01

    Highlights: • Anatase thin film of TiO{sub 2} was prepared by low temperature annealing. • Anatase TiO{sub 2} colloidal solution was obtained from amorphous form through solvothermal process. • Anatase TiO{sub 2} colloidal solution was used to prepare thin film on ITO glass. • Polymer solar cell fabricated on anatase TiO{sub 2} thin film showed 2.6% of PCE. - Abstract: To prepare the anatase TiO{sub 2} thin films on ITO glass, amorphous TiO{sub 2} colloidal solution was synthesized through the simple sol-gel method by using titanium (IV) isopropoxide as a precursor. This amorphous TiO{sub 2} colloidal solution was spread on ITO glass by spin-coating, then treated at 450 °C to obtain anatase TiO{sub 2} film (for device A). For other TiO{sub 2} films, amorphous TiO{sub 2} colloidal solution was treated through solvothermal process at 180 °C to obtain anatase TiO{sub 2} colloidal solution. This anatase TiO{sub 2} colloidal solution was spread on ITO glass by spin coating, and then annealed at 200 °C (for device B) and 130 °C (for device C), respectively. The average particle size of amorphous TiO{sub 2} colloidal solution was about 1.0 nm and that of anatase TiO{sub 2} colloidal solution was 10 nm. The thickness of TiO{sub 2} films was about 15 nm for all cases. When inverted polymer solar cells were fabricated by using these TiO{sub 2} films as an electron transport layer, the device C showed the highest PCE (2.6%) due to the lack of defect, uniformness and high light absorbance of TiO{sub 2} films. The result of this study can be applied for the preparation of inverted polymer solar cell using TiO{sub 2} films as a buffer layer at low temperature on plastic substrate by roll-to roll process.

  6. TiO{sub 2}-enriched polymeric powder coatings support human mesenchymal cell spreading and osteogenic differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Mozumder, Mohammad Sayem; Zhu, Jesse [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, N6A 5B9 (Canada); Perinpanayagam, Hiran, E-mail: Hiran.Perinpanayagam@schulich.uwo.ca [Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A 5C1 (Canada)

    2011-06-15

    Novel polymeric powder coatings (PPC) were prepared by ultrafine powder coating technology and shown to support human mesenchymal cell attachment and growth. PPC surfaces enriched with nano-TiO{sub 2} (nTiO{sub 2}) showed enhanced cellular responses, and were compared to commercially pure titanium (cpTi). After cell attachment and growth, osteogenic differentiation and bone matrix formation ensures osseointegration for implantable biomaterials. Therefore, the objective of this study was to determine if mesenchymal cells grown on PPC could undergo osteogenic differentiation by inducing Runx2 and bone matrix proteins, and then initiate mineralization. Atomic force microscopy revealed intricate three-dimensional micro-topographies, and the measures of nano-roughness and porosity were similar for all PPC surfaces. Scanning electron microscopy showed that the cells attached and spread out over all of the surfaces. After 1 week in osteogenic media, RT-PCR analysis showed the induction of Runx2, the up-regulation of type I collagen, and the initial detection of alkaline phosphatase and bone sialoprotein. After 4 weeks, Alizarin Red staining showed mineral deposition. However, cell spreading and osteogenic differentiation were significantly (P < 0.05) higher on the cpTi controls than on the PPC surfaces. Furthermore, spreading and differentiation were consistently higher on the titanium-enriched PPC-2, -3 and -4 than on the titanium-free PPC-1. Therefore, despite the presence of complex micro-topographies and nano-features, titanium-enrichment enhanced the cellular response, and pure titanium still provided the best substrate. These findings confirm the cytocompatibility of these novel polymeric coatings and suggest that titanium-enrichment and nTiO{sub 2} additives may enhance their performance.

  7. Mn-doped CdS quantum dots sensitized hierarchical TiO2 flower-rod for solar cell application

    International Nuclear Information System (INIS)

    Yu, Libo; Li, Zhen; Liu, Yingbo; Cheng, Fa; Sun, Shuqing

    2014-01-01

    A double-layered TiO 2 film which three dimensional (3D) fl