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Sample records for air-liquid interface cell

  1. A dose-controlled system for air-liquid interface cell exposure and application to zinc oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Ferron George A

    2009-12-01

    Full Text Available Abstract Background Engineered nanoparticles are becoming increasingly ubiquitous and their toxicological effects on human health, as well as on the ecosystem, have become a concern. Since initial contact with nanoparticles occurs at the epithelium in the lungs (or skin, or eyes, in vitro cell studies with nanoparticles require dose-controlled systems for delivery of nanoparticles to epithelial cells cultured at the air-liquid interface. Results A novel air-liquid interface cell exposure system (ALICE for nanoparticles in liquids is presented and validated. The ALICE generates a dense cloud of droplets with a vibrating membrane nebulizer and utilizes combined cloud settling and single particle sedimentation for fast (~10 min; entire exposure, repeatable (2. The cell-specific deposition efficiency is currently limited to 0.072 (7.2% for two commercially available 6-er transwell plates, but a deposition efficiency of up to 0.57 (57% is possible for better cell coverage of the exposure chamber. Dose-response measurements with ZnO nanoparticles (0.3-8.5 μg/cm2 showed significant differences in mRNA expression of pro-inflammatory (IL-8 and oxidative stress (HO-1 markers when comparing submerged and air-liquid interface exposures. Both exposure methods showed no cellular response below 1 μg/cm2 ZnO, which indicates that ZnO nanoparticles are not toxic at occupationally allowed exposure levels. Conclusion The ALICE is a useful tool for dose-controlled nanoparticle (or solute exposure of cells at the air-liquid interface. Significant differences between cellular response after ZnO nanoparticle exposure under submerged and air-liquid interface conditions suggest that pharmaceutical and toxicological studies with inhaled (nano-particles should be performed under the more realistic air-liquid interface, rather than submerged cell conditions.

  2. Cell deformation at the air-liquid interface induces Ca2+-dependent ATP release from lung epithelial cells.

    Science.gov (United States)

    Ramsingh, Ronaldo; Grygorczyk, Alexandra; Solecki, Anna; Cherkaoui, Lalla Siham; Berthiaume, Yves; Grygorczyk, Ryszard

    2011-04-01

    Extracellular nucleotides regulate mucociliary clearance in the airways and surfactant secretion in alveoli. Their release is exquisitely mechanosensitive and may be induced by stretch as well as airflow shear stress acting on lung epithelia. We hypothesized that, in addition, tension forces at the air-liquid interface (ALI) may contribute to mechanosensitive ATP release in the lungs. Local depletion of airway surface liquid, mucins, and surfactants, which normally protect epithelial surfaces, facilitate such release and trigger compensatory mucin and fluid secretion processes. In this study, human bronchial epithelial 16HBE14o(-) and alveolar A549 cells were subjected to tension forces at the ALI by passing an air bubble over the cell monolayer in a flow-through chamber, or by air exposure while tilting the cell culture dish. Such stimulation induced significant ATP release not involving cell lysis, as verified by ethidium bromide staining. Confocal fluorescence microscopy disclosed reversible cell deformation in the monolayer part in contact with the ALI. Fura 2 fluorescence imaging revealed transient intracellular Ca(2+) elevation evoked by the ALI, which did not entail nonspecific Ca(2+) influx from the extracellular space. ATP release was reduced by ∼40 to ∼90% from cells loaded with the Ca(2+) chelator BAPTA-AM and was completely abolished by N-ethylmalemide (1 mM). These experiments demonstrate that in close proximity to the ALI, surface tension forces are transmitted directly on cells, causing their mechanical deformation and Ca(2+)-dependent exocytotic ATP release. Such a signaling mechanism may contribute to the detection of local deficiency of airway surface liquid and surfactants on the lung surface. PMID:21239538

  3. Effects of Female Sex Hormones on Susceptibility to HSV-2 in Vaginal Cells Grown in Air-Liquid Interface.

    Science.gov (United States)

    Lee, Yung; Dizzell, Sara E; Leung, Vivian; Nazli, Aisha; Zahoor, Muhammad A; Fichorova, Raina N; Kaushic, Charu

    2016-01-01

    The lower female reproductive tract (FRT) is comprised of the cervix and vagina, surfaces that are continuously exposed to a variety of commensal and pathogenic organisms. Sexually transmitted viruses, such as herpes simplex virus type 2 (HSV-2), have to traverse the mucosal epithelial lining of the FRT to establish infection. The majority of current culture systems that model the host-pathogen interactions in the mucosal epithelium have limitations in simulating physiological conditions as they employ a liquid-liquid interface (LLI), in which both apical and basolateral surfaces are submerged in growth medium. We designed the current study to simulate in vivo conditions by growing an immortalized vaginal epithelial cell line (Vk2/E6E7) in culture with an air-liquid interface (ALI) and examined the effects of female sex hormones on their growth, differentiation, and susceptibility to HSV-2 under these conditions, in comparison to LLI cultures. ALI conditions induced Vk2/E6E7 cells to grow into multi-layered cultures compared to the monolayers present in LLI conditions. Vk2 cells in ALI showed higher production of cytokeratin in the presence of estradiol (E2), compared to cells grown in progesterone (P4). Cells grown under ALI conditions were exposed to HSV-2-green fluorescent protein (GFP) and the highest infection and replication was observed in the presence of P4. Altogether, this study suggests that ALI cultures more closely simulate the in vivo conditions of the FRT compared to the conventional LLI cultures. Furthermore, under these conditions P4 was found to confer higher susceptibility to HSV-2 infection in vaginal cells. The vaginal ALI culture system offers a better alternative to study host-pathogen interactions. PMID:27589787

  4. The Air Liquid-interface, a Skin Microenvironment, Promotes Growth of Melanoma Cells, but not Their Apoptosis and Invasion, through Activation of Mitogen-activated Protein Kinase

    International Nuclear Information System (INIS)

    The air-liquid interface (ALI) is a common microenvironment of the skin, but it is unknown whether the ALI affects melanoma cell behaviors. Using a collagen gel invasion assay, immunohistochemistry, and Western blots, here we show that melanoma cell proliferation in cultures with an ALI is higher than melanoma cell proliferation in submerged cultures. Bromodeoxyuridine (BrdU) uptake, an indicator of cell proliferation, of melanoma cells at the ALI was about 3 times that of submerged cells, while ALI and submerged melanoma cells had similar levels of single-stranded DNA (a marker of apoptosis). The ALI enhanced the expression of Raf-1, MEK-1 and pERK-1/2 components of the mitogen-activated protein kinase (MAPK) cascade, in cells more than the submerged condition did. The increases in BrdU uptake and pERK-1/2 expression promoted by ALI was abolished by the MEK inhibitor, PD-98059. ALI-treated and submerged melanoma cells did not infiltrate into the collagen gel, and they showed no significant difference in the expression of the invasion- and motility-related molecules, matrix metalloproteinase-1 and -9, laminin 5, and filamin A. Our data indicate that the ALI, a skin microenvironment, accelerates the growth, but not the apoptosis or invasion, of melanoma cells through MAPK activation

  5. The CULTEX RFS: A Comprehensive Technical Approach for the In Vitro Exposure of Airway Epithelial Cells to the Particulate Matter at the Air-Liquid Interface

    Directory of Open Access Journals (Sweden)

    Michaela Aufderheide

    2013-01-01

    Full Text Available The EU Regulation on Registration, Evaluation, Authorization and Restriction of Chemicals (REACH demands the implementation of alternative methods for analyzing the hazardous effects of chemicals including particulate formulations. In the field of inhalation toxicology, a variety of in vitro models have been developed for such studies. To simulate the in vivo situation, an adequate exposure device is necessary for the direct exposure of cultivated lung cells at the air-liquid interface (ALI. The CULTEX RFS fulfills these requirements and has been optimized for the exposure of cells to atomized suspensions, gases, and volatile compounds as well as micro- and nanosized particles. This study provides information on the construction and functional aspects of the exposure device. By using the Computational Fluid Dynamics (CFD analysis, the technical design was optimized to realize a stable, reproducible, and homogeneous deposition of particles. The efficiency of the exposure procedure is demonstrated by exposing A549 cells dose dependently to lactose monohydrate, copper(II sulfate, copper(II oxide, and micro- and nanoparticles. All copper compounds induced cytotoxic effects, most pronounced for soluble copper(II sulfate. Micro- and nanosized copper(II oxide also showed a dose-dependent decrease in the cell viability, whereby the nanosized particles decreased the metabolic activity of the cells more severely.

  6. Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air-liquid interface

    Energy Technology Data Exchange (ETDEWEB)

    Mihai, Cosmin; Chrisler, William B.; Xie, Yumei; Hu, Dehong; Szymanski, Craig J.; Tolic, Ana; Klein, Jessica; Smith, Jordan N.; Tarasevich, Barbara J.; Orr, Galya

    2015-02-01

    Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn2+) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn2+, together with organelle-specific fluorescent proteins, we quantified Zn2+ in single cells and organelles over time. We found that at the ALI, intracellular Zn2+ values peaked 3 h post exposure and decayed to normal values by 12 h, while in submersed cultures, intracellular Zn2+ values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn2+ values that were nearly 3 folds lower than the peak values generated by the lowest toxic dose of NPs in submersed cultures, and 8 folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn2+. At the ALI, the majority of intracellular Zn2+ was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn2+ following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. Together, our observations indicate that low but critical levels of intracellular Zn2+ have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes underlying the potent toxicity of airborne ZnO NPs.

  7. ELECTROHYDRODYNAMIC ENHANCED TRANSPORT AND TRAPPING OF AIRBORNE PARTICLES TO A MICROFLUIDIC AIR-LIQUID INTERFACE

    OpenAIRE

    Sandström, Niklas; Frisk, Thomas; Stemme, Göran; van der Wijngaart, Wouter

    2008-01-01

    We introduce a novel approach for greatly improved transport and trapping of airborne sample to a microfluidic analysis system by integrating an electrohydrodynamic (EHD) air pump with a microfluidic air-liquid interface. In our system, a negative corona discharge partially ionizes the air around a sharp electrode tip while the electrostatic field accelerates airborne particles towards an electrically grounded liquid surface, where they absorb. The air-liquid interface is fixated at the micro...

  8. Protein denaturation by combined effect of shear and air-liquid interface.

    Science.gov (United States)

    Maa, Y F; Hsu, C C

    1997-06-20

    The effect of shear alone on the aggregation of recombinant human growth hormone (rhGH) and recombinant human deoxyribonuclease (rhDNase) has been found to be insignificant. This study focused on the synergetic effect of shear and gas-liquid interface on these two model proteins. Two shearing systems, the concentric-cylinder shear device (CCSD) and the rotor/stator homogenizer, were used to generate high shear (> 10(6)) in aqueous solutions in the presence of air. High shear in the presence of an air-liquid interface had no major effect on rhDNase but caused rhGH to form noncovalent aggregates. rhGH aggregation was induced by the air-liquid interface and was found to increase with increasing protein concentration and the air-liquid interfacial area. The aggregation was irreversible and exhibited a first-order kinetics with respect to the protein concentration and air-liquid interfacial area. Shear and shear rate enhanced the interaction because of its continuous generation of new air-liquid interfaces. In the presence of a surfactant, aggregation could be delayed or prevented depending upon the type and the concentration of the surfactant. The effect of air-liquid interface on proteins at low shear was examined using a nitrogen bubbling method. We found that foaming is very detrimental to rhGH even though the shear involved is low. The use of anti-foaming materials could prevent rhGH aggregation during bubbling. The superior stability exhibited by rhDNase may be linked to the higher surface tension and lower foaming tendency of its aqueous solution. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 503-512, 1997. PMID:18636406

  9. Efficiency of air/liquid interfaces in detaching bacteria from a surface

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    Khodaparast, Sepideh; Stone, Howard

    2015-11-01

    Gas/liquid interfaces are known to be significantly more effective than shear stress in detaching microscale colloids from substrates by inducing surface tension forces. Providing that a three-phase contact at the interface of a gas bubble, the liquid phase and the particle occurs, the magnitude of the surface tension force can potentially exceed by orders of magnitude the adhesion force, which keeps the micro particles on the surface. We investigate the ability of a moving air/liquid interface to stimulate the detachment of bacteria from a surface. Bacteria are micron-sized living organisms with strong tendency to attach to almost any substrate that they come into contact with. Attachment of bacteria on the surface is a complex process regulated by diverse characteristics of their growth medium, substrate, and cell surface. Moreover, once fixed on the surface, the microorganisms evolve in time to create intricate biofilm structures, which are highly challenging to be removed. The objective of this study to characterise the efficiency of this detachment process as a function of bacterial attachment as well as hydrodynamic parameters such the surface tension and the interface velocity. Swiss National Science Foundation P2ELP2-158896.

  10. Quantitative assessment of radiation force effect at the dielectric air-liquid interface

    OpenAIRE

    Otávio Augusto Capeloto; Vitor Santaella Zanuto; Luis Carlos Malacarne; Mauro Luciano Baesso; Gustavo Vinicius Bassi Lukasievicz; Stephen Edward Bialkowski; Nelson Guilherme Castelli Astrath

    2016-01-01

    We induce nanometer-scale surface deformation by exploiting momentum conservation of the interaction between laser light and dielectric liquids. The effect of radiation force at the air-liquid interface is quantitatively assessed for fluids with different density, viscosity and surface tension. The imparted pressure on the liquids by continuous or pulsed laser light excitation is fully described by the Helmholtz electromagnetic force density.

  11. The production of drops by the bursting of a bubble at an air liquid interface

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    Darrozes, J. S.; Ligneul, P.

    1982-01-01

    The fundamental mechanism arising during the bursting of a bubble at an air-liquid interface is described. A single bubble was followed from an arbitrary depth in the liquid, up to the creation and motion of the film and jet drops. Several phenomena were involved and their relative order of magnitude was compared in order to point out the dimensionless parameters which govern each step of the motion. High-speed cinematography is employed. The characteristic bubble radius which separates the creation of jet drops from cap bursting without jet drops is expressed mathematically. The corresponding numerical value for water is 3 mm and agrees with experimental observations.

  12. Solid mesostructured polymer-surfactant films at the air-liquid interface.

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    Pegg, Jonathan C; Eastoe, Julian

    2015-08-01

    Pioneering work by Edler et al. has spawned a new sub-set of mesostructured materials. These are solid, self-supporting films comprising surfactant micelles encased within polymer hydrogel; composite polymer-surfactant films can be grown spontaneously at the air-liquid interface and have defined and controllable mesostructures. Addition of siliconalkoxide to polymer-surfactant mixtures allows for the growth of mesostructured hybrid polymer-surfactant silica films that retain film geometry after calcinations and exhibit superior mechanical properties to typically brittle inorganic films. Growing films at the air-liquid interface provides a rapid and simple means to prepare ordered solid inorganic films, and to date the only method for generating mesostructured films thick enough (up to several hundred microns) to be removed from the interface. Applications of these films could range from catalysis to encapsulation of hydrophobic species and drug delivery. Film properties and mesostructures are sensitive to surfactant structure, polymer properties and polymer-surfactant phase behaviour: herein it will be shown how film mesostructure can be tailored by directing these parameters, and some interesting analogies will be drawn with more familiar mesostructured silica materials. PMID:25127447

  13. The Influence of Sorbitol on the Adsorption of Surfactants at the Air-Liquid Interface

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    Staples; Thompson; Tucker; Penfold; Thomas; Lu

    1996-12-25

    Neutron reflection and surface tension have been used to study the adsorption of the nonionic surfactant monododecyl hexaethylene glycol (C12E6) and the mixed nonionic-anionic surfactants n-dodecyl triethylene glycol (C12E3) and Sodium dodecyl sulfate (SDS) at the air-liquid interface. Water and a sorbitol (d-glucitol, CH2OH(HCOH)4CH2OH)/water mixture were selected as the solvents. The addition of 300 g/liter of sorbitol to an aqueous solution of C12E6 reduces the critical micellar concentration, cmc, from approximately 7 x 10(-5) to approximately 3 x 10(-5) M, and increases the surface pressure at the cmc; the effect on the C12E3/SDS mixture is less. Despite these changes, the pattern of adsorption at the air-liquid interface is essentially unaltered by the addition of sorbitol, and the surface tension and neutron reflectivity data are in good agreement. The consequences of the sorbitol addition are however seen directly in the structure of the C12E6 monolayer. The ethylene oxide (EO) chain is more extended than in water, and more displaced from the solvent, consistent with dehydration of the ethylene oxide group. PMID:8978541

  14. Characterisation of pellicles formed by Acinetobacter baumannii at the air-liquid interface.

    Directory of Open Access Journals (Sweden)

    Yassine Nait Chabane

    Full Text Available The clinical importance of Acinetobacter baumannii is partly due to its natural ability to survive in the hospital environment. This persistence may be explained by its capacity to form biofilms and, interestingly, A. baumannii can form pellicles at the air-liquid interface more readily than other less pathogenic Acinetobacter species. Pellicles from twenty-six strains were morphologically classified into three groups: I egg-shaped (27%; II ball-shaped (50%; and III irregular pellicles (23%. One strain representative of each group was further analysed by Brewster's Angle Microscopy to follow pellicle development, demonstrating that their formation did not require anchoring to a solid surface. Total carbohydrate analysis of the matrix showed three main components: Glucose, GlcNAc and Kdo. Dispersin B, an enzyme that hydrolyzes poly-N-acetylglucosamine (PNAG polysaccharide, inhibited A. baumannii pellicle formation, suggesting that this exopolysaccharide contributes to pellicle formation. Also associated with the pellicle matrix were three subunits of pili assembled by chaperon-usher systems: the major CsuA/B, A1S_1510 (presented 45% of identity with the main pilin F17-A from enterotoxigenic Escherichia coli pili and A1S_2091. The presence of both PNAG polysaccharide and pili systems in matrix of pellicles might contribute to the virulence of this emerging pathogen.

  15. Characterisation of pellicles formed by Acinetobacter baumannii at the air-liquid interface.

    Science.gov (United States)

    Nait Chabane, Yassine; Marti, Sara; Rihouey, Christophe; Alexandre, Stéphane; Hardouin, Julie; Lesouhaitier, Olivier; Vila, Jordi; Kaplan, Jeffrey B; Jouenne, Thierry; Dé, Emmanuelle

    2014-01-01

    The clinical importance of Acinetobacter baumannii is partly due to its natural ability to survive in the hospital environment. This persistence may be explained by its capacity to form biofilms and, interestingly, A. baumannii can form pellicles at the air-liquid interface more readily than other less pathogenic Acinetobacter species. Pellicles from twenty-six strains were morphologically classified into three groups: I) egg-shaped (27%); II) ball-shaped (50%); and III) irregular pellicles (23%). One strain representative of each group was further analysed by Brewster's Angle Microscopy to follow pellicle development, demonstrating that their formation did not require anchoring to a solid surface. Total carbohydrate analysis of the matrix showed three main components: Glucose, GlcNAc and Kdo. Dispersin B, an enzyme that hydrolyzes poly-N-acetylglucosamine (PNAG) polysaccharide, inhibited A. baumannii pellicle formation, suggesting that this exopolysaccharide contributes to pellicle formation. Also associated with the pellicle matrix were three subunits of pili assembled by chaperon-usher systems: the major CsuA/B, A1S_1510 (presented 45% of identity with the main pilin F17-A from enterotoxigenic Escherichia coli pili) and A1S_2091. The presence of both PNAG polysaccharide and pili systems in matrix of pellicles might contribute to the virulence of this emerging pathogen. PMID:25360550

  16. Optical Measurement of Surface Tension in a Miniaturized Air-Liquid Interface and its Application in Lung Physiology

    OpenAIRE

    C Bertocchi; Ravasio, A.; Bernet, S.; Putz, G; Dietl, P.; Haller, T.

    2005-01-01

    We have previously shown that lamellar body-like particles, the form in which pulmonary surfactant is secreted, spontaneously disintegrate when they contact an air-liquid interface, eventually creating an interfacial film. Here, we combined these studies with a new technique enabling the simultaneous and non-invasive measurement of surface tension (γ). This method is a refinement of the pendant-drop principle. A sapphire cone with a 300-μm aperture keeps the experimental fluid by virtue of su...

  17. Pulmonary surfactant and macrophages studied at the air/liquid interface revealed by Brewster angle microscopy (BAM)

    Science.gov (United States)

    Telesford, Dana-Marie; Allen, Heather; Carlson, Tracy; Schlesinger, Larry

    2012-04-01

    The alveolus is lined with a complex mixture of lipids and proteins called pulmonary surfactant (PS) that lower surface tension at the alveolar air/liquid interface. The surface area of the lung for a 70 kg adult human at total lung capacity is ˜70 m^2. The large surface area and the direct exposure to the environment with every inhalation make this organ more susceptible to invasion by viruses, bacteria, and small particles. The most abundant cell recovered in human lung lavage is the alveolar macrophage which accounts for 85% of the total. The primary function of the alveolar macrophage is to defend the lung against invasion, but also in the clearance of surfactant components in the lung. Quintero and Wright,^1 in an in vitro study observing alveolar macrophage metabolism of two lipid components dipalmitoyl phosphatidylglycerol (DPPG) and dipalmitoyl phosphatidylcholine (DPPC), noted that DPPG was removed at a faster rate. The mechanism by which this process takes place is not fully understood and our aim is to investigate the interactions of macrophages with different lipids using Brewster angle microscopy. Preliminary studies suggest that THP-1 differentiated macrophages do not significantly perturb DPPC and DPPG monolayers and research utilizing alveolar macrophages is underway. The effect of PS SP-A and SP-D is also discussed.

  18. Effects and uptake of gold nanoparticles deposited at the air-liquid interface of a human epithelial airway model

    International Nuclear Information System (INIS)

    The impact of nanoparticles (NPs) in medicine and biology has increased rapidly in recent years. Gold NPs have advantageous properties such as chemical stability, high electron density and affinity to biomolecules, making them very promising candidates as drug carriers and diagnostic tools. However, diverse studies on the toxicity of gold NPs have reported contradictory results. To address this issue, a triple cell co-culture model simulating the alveolar lung epithelium was used and exposed at the air-liquid interface. The cell cultures were exposed to characterized aerosols with 15 nm gold particles (61 ng Au/cm2 and 561 ng Au/cm2 deposition) and incubated for 4 h and 24 h. Experiments were repeated six times. The mRNA induction of pro-inflammatory (TNFα, IL-8, iNOS) and oxidative stress markers (HO-1, SOD2) was measured, as well as protein induction of pro- and anti-inflammatory cytokines (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, GM-CSF, TNFα, INFγ). A pre-stimulation with lipopolysaccharide (LPS) was performed to further study the effects of particles under inflammatory conditions. Particle deposition and particle uptake by cells were analyzed by transmission electron microscopy and design-based stereology. A homogeneous deposition was revealed, and particles were found to enter all cell types. No mRNA induction due to particles was observed for all markers. The cell culture system was sensitive to LPS but gold particles did not cause any synergistic or suppressive effects. With this experimental setup, reflecting the physiological conditions more precisely, no adverse effects from gold NPs were observed. However, chronic studies under in vivo conditions are needed to entirely exclude adverse effects.

  19. Drop Impact on Liquid Surfaces: Formation of Lens and Spherical Drops at the Air-Liquid Interface

    CERN Document Server

    Yakhshi-Tafti, Ehsan; Kumar, Ranganathan; 10.1016/j.jcis.2010.06.029

    2010-01-01

    Droplets at the air-liquid interface of immiscible liquids usually form partially-submerged lens shapes (e.g. water on oil). In addition to this structure, we showed that droplets released from critical heights above the target liquid can sustain the impact and at the end maintain a spherical ball-shape configuration above the surface, despite undergoing large deformation. Spherical drops are unstable and will transform into the lens mode due to slight disturbances. Precision dispensing needles with various tip diameter sizes were used to release pendant drops of deionized water onto the surface of fluorocarbon liquid (FC-43, 3M). A cubic relationship was found between the nozzle tip diameter and the released droplet diameter. Drop impact was recorded by a high speed camera at a rate of 2000 frames per second. In order for the water drops to sustain the impact and retain a spherical configuration at the surface of the target liquid pool, it is required that they be of a critical size and be released from a ce...

  20. Drying nano particles solution on an oscillating tip at an air liquid interface: what we can learn, what we can do

    Directory of Open Access Journals (Sweden)

    Mariolle Denis

    2007-01-01

    Full Text Available AbstractEvaporation of fluid at micro and nanometer scale may be used to self-assemble nanometre-sized particles in suspension. Evaporating process can be used to gently control flow in micro and nanofluidics, thus providing a potential mean to design a fine pattern onto a surface or to functionalize a nanoprobe tip. In this paper, we present an original experimental approach to explore this open and rather virgin domain. We use an oscillating tip at an air liquid interface with a controlled dipping depth of the tip within the range of the micrometer. Also, very small dipping depths of a few ten nanometers were achieved with multi walls carbon nanotubes glued at the tip apex. The liquid is an aqueous solution of functionalized nanoparticles diluted in water. Evaporation of water is the driving force determining the arrangement of nanoparticles on the tip. The results show various nanoparticles deposition patterns, from which the deposits can be classified in two categories. The type of deposit is shown to be strongly dependent on whether or not the triple line is pinned and of the peptide coating of the gold nanoparticle. In order to assess the classification, companion dynamical studies of nanomeniscus and related dissipation processes involved with thinning effects are presented.

  1. Influence of gold species (AuCl4(-) and AuCl2(-)) on self-assembly of PS-b-P2VP in solutions and morphology of composite thin films fabricated at the air/liquid interfaces.

    Science.gov (United States)

    Zhao, Xingjuan; Wang, Qian; Zhang, Xiaokai; Lee, Yong-Ill; Liu, Hong-Guo

    2016-01-21

    Composite thin films doped with Au species were fabricated at an air/liquid interface via a series of steps, including the mass transfer of polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) across the liquid/liquid interface between a DMF/CHCl3 solution and an aqueous solution containing either AuCl4(-) or AuCl2(-), self-assembly of PS-b-P2VP in a mixed DMF-water solution, and adsorption and further self-organization of the formed aggregates at the air/liquid interface. This is a new approach for fabricating composite polymer films and can be completed within a very short time. AuCl4(-) and AuCl2(-) ions were found to significantly influence the self-assembly behavior of the block copolymer and the morphologies of the composite films, leading to the formation of nanowire arrays and a foam structure at the air/liquid interface, respectively, which originated from rod-like micelles and microcapsules that had formed in the respective solutions. The effect of the metal complex was analyzed based on the packing parameters of the amphiphilic polymer molecules in different microenvironments and the interactions between the pyridine groups and the metal chloride anions. In addition, these composite thin films exhibited stable and durable performance as heterogeneous catalysts for the hydrogenation of nitroaromatics in aqueous solutions. PMID:26688280

  2. Air/liquid collectors

    DEFF Research Database (Denmark)

    Jensen, Søren Østergaard; Olesen, Ole; Kristiansen, Finn Harken

    1997-01-01

    This report determine efficiency equations for combined air/liquid solar collectors by measurements on to different air/liquid collectors. Equations which contain all relevant informations on the solar collectors. A simulation program (Kviksol) has been modified in order to be able to handle this...... kind of collectors. The modified simulation program has been used for the determination of the surplus in performance which solar heating systems with this type of solar collectors for combined preheating of ventilation air and domestic hot water will have. The simulation program and the efficiency...

  3. Nanostructured Interfaces in Hybrid Solar Cells

    OpenAIRE

    Weickert, Jonas

    2014-01-01

    Excitonic solar cells are an emerging technology which holds the great promise of generating clean and sustainable photovoltaic power at lower cost than conventional silicon solar cells. In excitonic solar cells, the light is absorbed by organic semiconductors and dye molecules, which typically exhibit higher exciton binding energies than inorganic semiconductors. Therefore, free charge carriers can be generated only at interfaces between donor and acceptor materials. These interfaces can pro...

  4. Interfacing nanostructures to biological cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xing; Bertozzi, Carolyn R.; Zettl, Alexander K.

    2012-09-04

    Disclosed herein are methods and materials by which nanostructures such as carbon nanotubes, nanorods, etc. are bound to lectins and/or polysaccharides and prepared for administration to cells. Also disclosed are complexes comprising glycosylated nanostructures, which bind selectively to cells expressing glycosylated surface molecules recognized by the lectin. Exemplified is a complex comprising a carbon nanotube functionalized with a lipid-like alkane, linked to a polymer bearing repeated .alpha.-N-acetylgalactosamine sugar groups. This complex is shown to selectively adhere to the surface of living cells, without toxicity. In the exemplified embodiment, adherence is mediated by a multivalent lectin, which binds both to the cells and the .alpha.-N-acetylgalactosamine groups on the nanostructure.

  5. Autologous Cell Delivery to the Skin-Implant Interface via the Lumen of Percutaneous Devices in vitro

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    Antonio Peramo

    2010-11-01

    Full Text Available Induced tissue regeneration around percutaneous medical implants could be a useful method to prevent the failure of the medical device, especially when the epidermal seal around the implant is disrupted and the implant must be maintained over a long period of time. In this manuscript, a novel concept and technique is introduced in which autologous keratinocytes were delivered to the interfacial area of a skin-implant using the hollow interior of a fixator pin as a conduit. Full thickness human skin explants discarded from surgeries were cultured at the air-liquid interface and were punctured to fit at the bottom of hollow cylindrical stainless steel fixator pins. Autologous keratinocytes, previously extracted from the same piece of skin and cultured separately, were delivered to the specimens thorough the interior of the hollow pins. The delivered cells survived the process and resembled undifferentiated epithelium, with variations in size and shape. Viability was demonstrated by the lack of morphologic evidence of necrosis or apoptosis. Although the cells did not form organized epithelial structures, differentiation toward a keratinocyte phenotype was evident immunohistochemically. These results suggest that an adaptation of this technique could be useful for the treatment of complications arising from the contact between skin and percutaneous devices in vivo.

  6. Emitter/absorber interface of CdTe solar cells

    Science.gov (United States)

    Song, Tao; Kanevce, Ana; Sites, James R.

    2016-06-01

    The performance of CdTe solar cells can be very sensitive to the emitter/absorber interface, especially for high-efficiency cells with high bulk lifetime. Performance losses from acceptor-type interface defects can be significant when interface defect states are located near mid-gap energies. Numerical simulations show that the emitter/absorber band alignment, the emitter doping and thickness, and the defect properties of the interface (i.e., defect density, defect type, and defect energy) can all play significant roles in the interface recombination. In particular, a type I heterojunction with small conduction-band offset (0.1 eV ≤ ΔEC ≤ 0.3 eV) can help maintain good cell efficiency in spite of high interface defect density, much like with Cu(In,Ga)Se2 (CIGS) cells. The basic principle is that positive ΔEC, often referred to as a "spike," creates an absorber inversion and hence a large hole barrier adjacent to the interface. As a result, the electron-hole recombination is suppressed due to an insufficient hole supply at the interface. A large spike (ΔEC ≥ 0.4 eV), however, can impede electron transport and lead to a reduction of photocurrent and fill-factor. In contrast to the spike, a "cliff" (ΔEC CdTe solar cells, but the CdS/CdTe interface is in the cliff category and is not favorable from the band-offset perspective. The ΔEC of other n-type emitter choices, such as (Mg,Zn)O, Cd(S,O), or (Cd,Mg)Te, can be tuned by varying the elemental ratio for an optimal positive value of ΔEC. These materials are predicted to yield higher voltages and would therefore be better candidates for the CdTe-cell emitter.

  7. Emitter/absorber interface of CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Song, Tao [Physics Department, Colorado State University, Fort Collins, Colorado 80523, USA; Kanevce, Ana [National Renewable Energy Laboratory, Golden, Colorado 80401, USA; Sites, James R. [Physics Department, Colorado State University, Fort Collins, Colorado 80523, USA

    2016-06-17

    The performance of CdTe solar cells can be very sensitive to their emitter/absorber interfaces, especially for high-efficiency cells with improved bulk properties. When interface defect states are located at efficient recombination energies, performance losses from acceptor-type interface defects can be significant. Numerical simulations show that the emitter/absorber band alignment, the emitter doping and thickness, and the defect properties of the interface (i.e. defect density, defect type, and defect energy) can all play significant roles in the interface recombination. In particular, a type I heterojunction with small conduction-band offset (0.1 eV cell efficiency in spite of high interface defect density, much like with Cu(In,Ga)Se2 (CIGS) cells. The basic principle is that positive ..delta..EC, often referred to as a 'spike', creates an absorber inversion and hence a large hole barrier adjacent to the interface. As a result, the electron-hole recombination is suppressed due to an insufficient hole supply at the interface. A large spike (..delta..EC >/= 0.4 eV), however, can impede electron transport and lead to a reduction of photocurrent and fill-factor. In contrast to the spike, a 'cliff' (.delta..EC < 0 eV) is likely to allow many holes in the vicinity of the interface, which will assist interface recombination and result in a reduced open-circuit voltage. In addition, a thin and highly-doped emitter can invert the absorber, form a large hole barrier, and decrease device performance losses due to high interface defect density. CdS is the most common emitter material used in CdTe solar cells, but the CdS/CdTe interface is in the cliff category and is not favorable from the band-offset perspective. Other n-type emitter choices, such as (Mg,Zn)O, Cd(S,O), or (Cd,Mg)Te, can be tuned by varying the elemental ratio for an optimal positive value of ..delta..EC. These materials are predicted

  8. Graphene-Based Interfaces Do Not Alter Target Nerve Cells.

    Science.gov (United States)

    Fabbro, Alessandra; Scaini, Denis; León, Verónica; Vázquez, Ester; Cellot, Giada; Privitera, Giulia; Lombardi, Lucia; Torrisi, Felice; Tomarchio, Flavia; Bonaccorso, Francesco; Bosi, Susanna; Ferrari, Andrea C; Ballerini, Laura; Prato, Maurizio

    2016-01-26

    Neural-interfaces rely on the ability of electrodes to transduce stimuli into electrical patterns delivered to the brain. In addition to sensitivity to the stimuli, stability in the operating conditions and efficient charge transfer to neurons, the electrodes should not alter the physiological properties of the target tissue. Graphene is emerging as a promising material for neuro-interfacing applications, given its outstanding physico-chemical properties. Here, we use graphene-based substrates (GBSs) to interface neuronal growth. We test our GBSs on brain cell cultures by measuring functional and synaptic integrity of the emerging neuronal networks. We show that GBSs are permissive interfaces, even when uncoated by cell adhesion layers, retaining unaltered neuronal signaling properties, thus being suitable for carbon-based neural prosthetic devices. PMID:26700626

  9. Corrosion protected, multi-layer fuel cell interface

    International Nuclear Information System (INIS)

    A fuel cell stack is described comprising stacked elements, including at least one corrosion resistant, electrically conductive, fluid impervious interface arranged between two of the elements which are not adjacent to one another. The interface consists of a non-cupreous metal coating formed on at least one of the elements and a conductive layer bonded to at least the metal-coated element by a hot-pressed resin. The resin substantially fills any pores in the conductive layer

  10. Enhanced invasion of metastatic cancer cells via extracellular matrix interface.

    Directory of Open Access Journals (Sweden)

    Jiangrui Zhu

    Full Text Available Cancer cell invasion is a major component of metastasis and is responsible for extensive cell diffusion into and major destruction of tissues. Cells exhibit complex invasion modes, including a variety of collective behaviors. This phenomenon results in the structural heterogeneity of the extracellular matrix (ECM in tissues. Here, we systematically investigated the environmental heterogeneity facilitating tumor cell invasion via a combination of in vitro cell migration experiments and computer simulations. Specifically, we constructed an ECM microenvironment in a microfabricated biochip and successfully created a three-dimensional (3D funnel-like matrigel interface inside. Scanning electron microscopy demonstrated that the interface was at the interior defects of the nano-scale molecular anisotropic orientation and the localized structural density variations in the matrigel. Our results, particularly the correlation of the collective migration pattern with the geometric features of the funnel-like interface, indicate that this heterogeneous in vitro ECM structure strongly guides and promotes aggressive cell invasion in the rigid matrigel space. A cellular automaton model was proposed based on our experimental observations, and the associated quantitative analysis indicated that cell invasion was initiated and controlled by several mechanisms, including microenvironment heterogeneity, long-range cell-cell homotype and gradient-driven directional cellular migration. Our work shows the feasibility of constructing a complex and heterogeneous in vitro 3D ECM microenvironment that mimics the in vivo environment. Moreover, our results indicate that ECM heterogeneity is essential in controlling collective cell invasive behaviors and therefore determining metastasis efficiency.

  11. Interference-robust Air Interface for 5G Small Cells

    DEFF Research Database (Denmark)

    Tavares, Fernando Menezes Leitão

    new 5th Generation (5G) RAT standard is expected to support data rates greater than 10 Gbps with very low latency, very low energy consumption and provide the required scalability that will allow the network to transport a 1000 to 10000 times more mobile data traffic in 2020 than a similar network...... would do in 2010. To meet these challenging network capacity expansion requirements, the design of the new 5G RAT standard will make use of three main strategies: more antennas, more spectrum and more cells. All these strategies will have important roles in the new system, but the deployment of a...... expected gains. Due to the fundamental role of inter-cell interference in this type of networks, the inter-cell interference problem must be addressed since the beginning of the design of the new standard. This Ph.D. thesis deals with the design of an interference-robust air interface for 5G small cell...

  12. Liquid chromatography/Fourier transform IR spectrometry interface flow cell

    Science.gov (United States)

    Johnson, Charles C.; Taylor, Larry T.

    1986-01-01

    A zero dead volume (ZDV) microbore high performance liquid chromatography (.mu.HPLC)/Fourier transform infrared (FTIR) interface flow cell includes an IR transparent crystal having a small diameter bore therein through which a sample liquid is passed. The interface flow cell further includes a metal holder in combination with a pair of inner, compressible seals for directly coupling the thus configured spectrometric flow cell to the outlet of a .mu.HPLC column end fitting to minimize the transfer volume of the effluents exiting the .mu.HPLC column which exhibit excellent flow characteristics due to the essentially unencumbered, open-flow design. The IR beam passes transverse to the sample flow through the circular bore within the IR transparent crystal, which is preferably comprised of potassium bromide (KBr) or calcium fluoride (CaF.sub.2), so as to minimize interference patterns and vignetting encountered in conventional parallel-plate IR cells. The long IR beam pathlength and lensing effect of the circular cross-section of the sample volume in combination with the refractive index differences between the solvent and the transparent crystal serve to focus the IR beam in enhancing sample detection sensitivity by an order of magnitude.

  13. Multifunctional Fullerene Derivative for Interface Engineering in Perovskite Solar Cells.

    Science.gov (United States)

    Li, Yaowen; Zhao, Yue; Chen, Qi; Yang, Yang Michael; Liu, Yongsheng; Hong, Ziruo; Liu, Zonghao; Hsieh, Yao-Tsung; Meng, Lei; Li, Yongfang; Yang, Yang

    2015-12-16

    In perovskite based planar heterojunction solar cells, the interface between the TiO2 compact layer and the perovskite film is critical for high photovoltaic performance. The deep trap states on the TiO2 surface induce several challenging issues, such as charge recombination loss and poor stability etc. To solve the problems, we synthesized a triblock fullerene derivative (PCBB-2CN-2C8) via rational molecular design for interface engineering in the perovskite solar cells. Modifying the TiO2 surface with the compound significantly improves charge extraction from the perovskite layer. Together with its uplifted surface work function, open circuit voltage and fill factor are dramatically increased from 0.99 to 1.06 V, and from 72.2% to 79.1%, respectively, resulting in 20.7% improvement in power conversion efficiency for the best performing devices. Scrutinizing the electrical properties of this modified interfacial layer strongly suggests that PCBB-2CN-2C8 passivates the TiO2 surface and thus reduces charge recombination loss caused by the deep trap states of TiO2. The passivation effect is further proven by stability testing of the perovskite solar cells with shelf lifetime under ambient conditions improved by a factor of more than 4, from ∼40 h to ∼200 h, using PCBB-2CN-2C8 as the TiO2 modification layer. This work offers not only a promising material for cathode interface engineering, but also provides a viable approach to address the challenges of deep trap states on TiO2 surface in planar perovskite solar cells. PMID:26592525

  14. Study of air-liquid flow patterns in hydrocyclone enhanced by air bubbles

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Z.; Wang, H.; Tu, S.T. [School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai (China)

    2009-01-15

    In order to improve the oil-water separation efficiency of a hydrocyclone, a new process utilizing air bubbles has been developed to enhance separation performance. Using the two-component phase Doppler particle analyzer (PDPA) technique, the velocities of two phases, air and liquid, and air bubble diameter were measured in a hydrocyclone. The air-liquid mixing pump can produce 15 to 60 {mu}m-diameter air bubbles in water. There is an optimum air-liquid ratio for oil-water separation of a hydrocyclone enhanced by air bubbles. An air core occurs in the hydrocyclone when the air-liquid ratio is more than 1 %. The velocities of air bubbles have a similar flow pattern to the water phase. The axial and tangential velocity differences of the air bubbles at different air-liquid ratio are greater near the wall and near the core of the hydrocyclone. The measured results show that the size distribution of the air bubbles produced by the air-liquid mixing pump is beneficial to the process where air bubbles capture oil droplets in the hydrocyclone. These studies are helpful to understand the separation mechanism of a hydrocyclone enhanced by air bubbles. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  15. Inverters for interfacing of solar cells with the power grid

    Science.gov (United States)

    Karamanzanis, G. N.; Jackson, R. D.

    In this work, based on a research course in the Engineering Dep. Cambridge University, some non-classical inverter circuits are studied. They can be used for interfacing solar cells with the power grid at low voltage (230V) and at low power level. They are based on d.c. choppers which have a fast switching transistor. Their theoretical efficiency is 100 percent and they provide a satisfactory output current waveform in phase to the a.c. line voltage. The problems of control are also studied using a suitable mathematical model.

  16. T cell behavior at the maternal-fetal interface.

    Science.gov (United States)

    Nancy, Patrice; Erlebacher, Adrian

    2014-01-01

    Understanding the function of T cells at the maternal-fetal interface remains one of the most difficult problems in reproductive immunology. A great deal of work over the last two decades has led to the view that the T cells that populate the decidua have important roles in both normal and pathological pregnancies, but the exact nature of these roles has remained unclear. Indeed, the old assumption that decidual T cells are uniformly threatening to fetal survival because the placenta is fundamentally an 'allograft' has given way to the idea that different T cell subsets contribute in different ways to pregnancy success or failure. Accordingly, some T cells are thought to protect the placenta from immune rejection and facilitate embryo implantation, while others are thought to contribute to pregnancy pathologies such as preeclampsia and spontaneous abortion. Here, we review the current state of information on the behavior of decidual T cells with a focus on both mouse and human studies, and with an emphasis on the many unresolved areas within this overall emerging framework. PMID:25023685

  17. Pneumocystis jirovecii Can Be Productively Cultured in Differentiated CuFi-8 Airway Cells

    OpenAIRE

    Schildgen, Verena; Mai, Stephanie; Khalfaoui, Soumaya; Lüsebrink, Jessica; Pieper, Monika; Tillmann, Ramona L.; Brockmann, Michael; Schildgen, Oliver

    2014-01-01

    ABSTRACT Although Pneumocystis jirovecii is a well-known and serious pathogen, all previous attempts to isolate, cultivate, and propagate this fungus have failed. This serious challenge in microbiology was addressed in the present study. We examined whether P. jirovecii could be cultured in a permanent three-dimensional air-liquid interface culture system formed by CuFi-8 cells, a differentiated pseudostratified airway epithelial cell line. Cultured pseudostratified cells were inoculated with...

  18. Crystalline architectures at the air-liquid interface: From nucleation to engineering

    DEFF Research Database (Denmark)

    Rapaport, H.; Kuzmenko, I.; Kjær, K.;

    1999-01-01

    Ordered molecular clusters with a length scale down to few nanometers are currently attracting wide attention in the physical and biological sciences. The design and preparation of functional materials such as thin-layered microstructures, reagent films for biosensors, and devices for...

  19. Morphological and proteomic analysis of early stage air-liquid interface biofilm formation in Mycobacterium smegmatis

    Czech Academy of Sciences Publication Activity Database

    Sochorová, Zuzana; Petráčková, Denisa; Sitařová, B.; Buriánková, Karolína; Bezoušková, Silvia; Benada, Oldřich; Kofroňová, Olga; Janeček, Jiří; Halada, Petr; Weiser, Jaroslav

    2014-01-01

    Roč. 160, JUL 2014 (2014), s. 1346-1356. ISSN 1350-0872 R&D Projects: GA AV ČR IAA500200913 Institutional support: RVO:61388971 Keywords : RHODOCOCCUS-JOSTII RHA1 * BACILLUS -SUBTILIS * GLASS-BEADS Subject RIV: EE - Microbiology, Virology Impact factor: 2.557, year: 2014

  20. Triglyceride metabolism in human keratinocytes cultured at the air-liquid interface

    NARCIS (Netherlands)

    M. Ponec (Maria); J. Kempenaar (Johanna); A. Weerheim (Arij); L. de Lannoy (Larissa); I. Kalkman (Ina); H. Jansen

    1995-01-01

    textabstractAlthough epidermis reconstructed in vitro histologically demonstrates the presence of fully differentiated tissue with cornified strata, it does not synthesize or release epidermal barrier lipids in the same proportions as does native skin, causing the barrier function to be impaired. Li

  1. Air-liquid interface biofilms of Bacillus cereus: formation, sporulation, and dispersion

    OpenAIRE

    Wijman, J.G.E.; Leeuw, van der, R.; Moezelaar, R.; Zwietering, M.H.; Abee, T.

    2007-01-01

    Biofilm formation by Bacillus cereus was assessed using 56 strains of B. cereus, including the two sequenced strains, ATCC 14579 and ATCC 10987. Biofilm production in microtiter plates was found to be strongly dependent on incubation time, temperature, and medium, as well as the strain used, with some strains showing biofilm formation within 24 h and subsequent dispersion within the next 24 h. A selection of strains was used for quantitative analysis of biofilm formation on stainless steel co...

  2. Interface engineering for efficient fullerene-free organic solar cells

    International Nuclear Information System (INIS)

    We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell

  3. Interface engineering for efficient fullerene-free organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shivanna, Ravichandran; Narayan, K. S., E-mail: rajaram@jncasr.ac.in, E-mail: narayan@jncasr.ac.in [Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India); Rajaram, Sridhar, E-mail: rajaram@jncasr.ac.in, E-mail: narayan@jncasr.ac.in [International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India)

    2015-03-23

    We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell.

  4. Directing cell migration and organization via nanocrater-patterned cell-repellent interfaces

    Science.gov (United States)

    Jeon, Hojeong; Koo, Sangmo; Reese, Willie Mae; Loskill, Peter; Grigoropoulos, Costas P.; Healy, Kevin E.

    2015-09-01

    Although adhesive interactions between cells and nanostructured interfaces have been studied extensively, there is a paucity of data on how nanostructured interfaces repel cells by directing cell migration and cell-colony organization. Here, by using multiphoton ablation lithography to pattern surfaces with nanoscale craters of various aspect ratios and pitches, we show that the surfaces altered the cells’ focal-adhesion size and distribution, thus affecting cell morphology, migration and ultimately localization. We also show that nanocrater pitch can disrupt the formation of mature focal adhesions to favour the migration of cells towards higher-pitched regions, which present increased planar area for the formation of stable focal adhesions. Moreover, by designing surfaces with variable pitch but constant nanocrater dimensions, we were able to create circular and striped cellular patterns. Our surface-patterning approach, which does not involve chemical treatments and can be applied to various materials, represents a simple method to control cell behaviour on surfaces.

  5. Advances in the Lightweight Air-Liquid Composite Heat Exchanger Development for Space Exploration Applications

    Science.gov (United States)

    Shin, E. Eugene; Johnston, J. Chris; Haas, Daniel

    2011-01-01

    An advanced, lightweight composite modular Air/Liquid (A/L) Heat Exchanger (HX) Prototype for potential space exploration thermal management applications was successfully designed, manufactured, and tested. This full-scale Prototype consisting of 19 modules, based on recommendations from its predecessor Engineering Development unit (EDU) but with improved thermal characteristics and manufacturability, was 11.2 % lighter than the EDU and achieves potentially a 42.7% weight reduction from the existing state-of-the-art metallic HX demonstrator. However, its higher pressure drop (0.58 psid vs. 0.16 psid of the metal HX) has to be mitigated by foam material optimizations and design modifications including a more systematic air channel design. Scalability of the Prototype design was validated experimentally by comparing manufacturability and performance between the 2-module coupon and the 19-module Prototype. The Prototype utilized the thermally conductive open-cell carbon foam material but with lower density and adopted a novel high-efficiency cooling system with significantly increased heat transfer contact surface areas, improved fabricability and manufacturability compared to the EDU. Even though the Prototype was required to meet both the thermal and the structural specifications, accomplishing the thermal requirement was a higher priority goal for this first version. Overall, the Prototype outperformed both the EDU and the corresponding metal HX, particularly in terms of specific heat transfer, but achieved 93.4% of the target. The next generation Prototype to achieve the specification target, 3,450W would need 24 core modules based on the simple scaling factor. The scale-up Prototype will weigh about 14.7 Kg vs. 21.6 Kg for the metal counterpart. The advancement of this lightweight composite HX development from the original feasibility test coupons to EDU to Prototype is discussed in this paper.

  6. Three dimensional vortices and interfaces in Hele-Shaw cells

    International Nuclear Information System (INIS)

    A model of nonviscous flow, based on the Biot-Savart equations is used to examine the existence of singularities in three dimensional, incompressible, hydrodynamic equations. The results suggest a fairly simple physical mechanism, which could lead to the formation of singularities in the nonviscous case: two vortex tubes with opposite circulations pair up and stretch each other, until the radii of the vortex cores become extremely small, causing a divergence of the vorticity. The cases of a perfect and a slightly viscous fluid are considered. The results are unclear as to whether the vorticity of a slightly viscous fluid can become infinite or not, and whether singularities exist. The dynamics of hydrodynamic interfaces are also investigated. The propagation of bubbles in a slightly viscous fluid, in a Hele-Shaw cell are described

  7. A glucose fuel cell for implantable brain-machine interfaces.

    Directory of Open Access Journals (Sweden)

    Benjamin I Rapoport

    Full Text Available We have developed an implantable fuel cell that generates power through glucose oxidation, producing 3.4 μW cm(-2 steady-state power and up to 180 μW cm(-2 peak power. The fuel cell is manufactured using a novel approach, employing semiconductor fabrication techniques, and is therefore well suited for manufacture together with integrated circuits on a single silicon wafer. Thus, it can help enable implantable microelectronic systems with long-lifetime power sources that harvest energy from their surrounds. The fuel reactions are mediated by robust, solid state catalysts. Glucose is oxidized at the nanostructured surface of an activated platinum anode. Oxygen is reduced to water at the surface of a self-assembled network of single-walled carbon nanotubes, embedded in a Nafion film that forms the cathode and is exposed to the biological environment. The catalytic electrodes are separated by a Nafion membrane. The availability of fuel cell reactants, oxygen and glucose, only as a mixture in the physiologic environment, has traditionally posed a design challenge: Net current production requires oxidation and reduction to occur separately and selectively at the anode and cathode, respectively, to prevent electrochemical short circuits. Our fuel cell is configured in a half-open geometry that shields the anode while exposing the cathode, resulting in an oxygen gradient that strongly favors oxygen reduction at the cathode. Glucose reaches the shielded anode by diffusing through the nanotube mesh, which does not catalyze glucose oxidation, and the Nafion layers, which are permeable to small neutral and cationic species. We demonstrate computationally that the natural recirculation of cerebrospinal fluid around the human brain theoretically permits glucose energy harvesting at a rate on the order of at least 1 mW with no adverse physiologic effects. Low-power brain-machine interfaces can thus potentially benefit from having their implanted units

  8. PRODUCT INNOVATION AND THE GROWTH OF THE LARGE FIRM: THE CASE OF AIR LIQUIDE, 1902-1930

    Directory of Open Access Journals (Sweden)

    Michael S. Smith

    1999-01-01

    Full Text Available This paper traces the early development of Air Liquide, the world’s largest producer of industrial gases. By illustrating the dynamism of French industrial capitalism in the early twentieth century, the Air Liquide story calls into question the image of the French as also-rans in the Second Industrial Revolution. The story of Air Liquide also shows that geographical expansion and product diversification do not always lead to adoption of the multidivisional form (as in the case of Du Pont. Instead, Air Liquide remained a relatively small corporation at the center of a cluster of related firms. This paper suggests that the timing of product diversification may explain the differing organizational histories of Air Liquide and Du Pont.

  9. Lineage-specific interface proteins match up the cell cycle and differentiation in embryo stem cells

    DEFF Research Database (Denmark)

    Re, Angela; Workman, Christopher; Waldron, Levi;

    2014-01-01

    The shortage of molecular information on cell cycle changes along embryonic stem cell (ESC) differentiation prompts an in silico approach, which may provide a novel way to identify candidate genes or mechanisms acting in coordinating the two programs. We analyzed germ layer specific gene expression...... changes during the cell cycle and ESC differentiation by combining four human cell cycle transcriptome profiles with thirteen in vitro human ESC differentiation studies. To detect cross-talk mechanisms we then integrated the transcriptome data that displayed differential regulation with protein...... interaction data. A new class of non-transcriptionally regulated genes was identified, encoding proteins which interact systematically with proteins corresponding to genes regulated during the cell cycle or cell differentiation, and which therefore can be seen as interface proteins coordinating the two...

  10. Interface Engineering of High Efficiency Organic-Silicon Heterojunction Solar Cells.

    Science.gov (United States)

    Yang, Lixia; Liu, Yaoping; Chen, Wei; Wang, Yan; Liang, Huili; Mei, Zengxia; Kuznetsov, Andrej; Du, Xiaolong

    2016-01-13

    Insufficient interface conformity is a challenge faced in hybrid organic-silicon heterojunction solar cells because of using conventional pyramid antireflection texturing provoking the porosity of interface. In this study, we tested alternative textures, in particular rounded pyramids and inverted pyramids to compare the performance. It was remarkably improved delivering 7.61%, 8.91% and 10.04% efficiency employing conventional, rounded, and inverted pyramids, respectively. The result was interpreted in terms of gradually improving conformity of the Ag/organic/silicon interface, together with the gradually decreasing serial resistance. Altogether, the present data may guide further efforts arising the interface engineering for mastering high efficient heterojunction solar cells. PMID:26701061

  11. Nanoemulsions obtained via bubble-bursting at a compound interface

    Science.gov (United States)

    Feng, Jie; Roché, Matthieu; Vigolo, Daniele; Arnaudov, Luben N.; Stoyanov, Simeon D.; Gurkov, Theodor D.; Tsutsumanova, Gichka G.; Stone, Howard A.

    2014-08-01

    Bursting of bubbles at an air/liquid interface is a familiar occurrence relevant to foam stability, cell cultures in bioreactors and ocean-atmosphere mass transfer. In the latter case, bubble-bursting leads to the dispersal of sea-water aerosols in the surrounding air. Here we show that bubbles bursting at a compound air/oil/water-with-surfactant interface can disperse submicrometre oil droplets in water. Dispersal results from the detachment of an oil spray from the bottom of the bubble towards water during bubble collapse. We provide evidence that droplet size is selected by physicochemical interactions between oil molecules and the surfactants rather than by hydrodynamics. We demonstrate the unrecognized role that this dispersal mechanism may play in the fate of the sea surface microlayer and of pollutant spills by dispersing petroleum in the water column. Finally, our system provides an energy-efficient route, with potential upscalability, for applications in drug delivery, food production and materials science.

  12. Nanoemulsions obtained via bubble bursting at a compound interface

    CERN Document Server

    Feng, Jie; Vigolo, Daniele; Arnaudov, Luben N; Stoyanov, Simeon D; Gurkov, Theodor D; Tsutsumanova, Gichka G; Stone, Howard A

    2013-01-01

    The bursting of bubbles at an air/liquid interface is a familiar occurrence important to foam stability, cell cultures in bioreactors and mass transfer between the sea and atmosphere. Here we document the hitherto unreported formation and dispersal into the water column of submicrometre oil droplets following bubble bursting at a compound air/oil/water-with-surfactant interface. We show that dispersal results from the detachment of an oil spray from the bottom of the bubble towards water during bubble collapse. We provide evidence that droplet size is selected by physicochemical interactions between oil molecules and the surfactants rather than by hydrodynamic effects. We illustrate the unrecognized role that this dispersal mechanism may play in the fate of the sea surface micro-layer and of pollutant spills by dispersing petroleum in the water column. Finally, our system provides an energy-efficient route, with potential upscalability and wide applicability, for applications in drug delivery, food production...

  13. An application programming interface for CellNetAnalyzer.

    Science.gov (United States)

    Klamt, Steffen; von Kamp, Axel

    2011-08-01

    CellNetAnalyzer (CNA) is a MATLAB toolbox providing computational methods for studying structure and function of metabolic and cellular signaling networks. In order to allow non-experts to use these methods easily, CNA provides GUI-based interactive network maps as a means of parameter input and result visualization. However, with the availability of high-throughput data, there is a need to make CNA's functionality also accessible in batch mode for automatic data processing. Furthermore, as some algorithms of CNA are of general relevance for network analysis it would be desirable if they could be called as sub-routines by other applications. For this purpose, we developed an API (application programming interface) for CNA allowing users (i) to access the content of network models in CNA, (ii) to use CNA's network analysis capabilities independent of the GUI, and (iii) to interact with the GUI to facilitate the development of graphical plugins. Here we describe the organization of network projects in CNA and the application of the new API functions to these projects. This includes the creation of network projects from scratch, loading and saving of projects and scenarios, and the application of the actual analysis methods. Furthermore, API functions for the import/export of metabolic models in SBML format and for accessing the GUI are described. Lastly, two example applications demonstrate the use and versatile applicability of CNA's API. CNA is freely available for academic use and can be downloaded from http://www.mpi-magdeburg.mpg.de/projects/cna/cna.html. PMID:21315797

  14. Fundamental processes of exciton scattering at organic solar-cell interfaces: One-dimensional model calculation

    Science.gov (United States)

    Masugata, Yoshimitsu; Iizuka, Hideyuki; Sato, Kosuke; Nakayama, Takashi

    2016-08-01

    Fundamental processes of exciton scattering at organic solar-cell interfaces were studied using a one-dimensional tight-binding model and by performing a time-evolution simulation of electron–hole pair wave packets. We found the fundamental features of exciton scattering: the scattering promotes not only the dissociation of excitons and the generation of interface-bound (charge-transferred) excitons but also the transmission and reflection of excitons depending on the electron and hole interface offsets. In particular, the dissociation increases in a certain region of an interface offset, while the transmission shows resonances with higher-energy bound-exciton and interface bound-exciton states. We also studied the effects of carrier-transfer and potential modulations at the interface and the scattering of charged excitons, and we found trap dissociations where one of the carriers is trapped around the interface after the dissociation.

  15. Understanding on Interface Contribution to the Electrode Performance of Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Grahl-Madsen, L.

    2016-01-01

    The commercialization of proton exchange membrane fuel cells (PEMFCs) is closer to the reality than ever before. Electrode interface development can bring a boost to the last few steps. Here, we explore electrode properties from its interface structure, especially the ionomer phase. Electrodes...

  16. Predicting the interface morphologies of silicon films on arbitrary substrates: application in solar cells.

    Science.gov (United States)

    Jovanov, Vladislav; Xu, Xu; Shrestha, Shailesh; Schulte, Melanie; Hüpkes, Jürgen; Knipp, Dietmar

    2013-08-14

    A three-dimensional model that predicts the interface morphologies of silicon thin-film solar cells prepared on randomly textured substrates was developed and compared to experimental data. The surface morphologies of silicon solar cells were calculated by using atomic force microscope scans of the textured substrates and the film thickness as input data. Calculated surface morphologies of silicon solar cells are in good agreement with experimentally measured morphologies. A detailed description of the solar cell interface morphologies is necessary to understand light-trapping in silicon single junction and micromorph tandem thin-film solar cells and derive optimal light-trapping structures. PMID:23889117

  17. Heterogeneous ceramic interfaces in solid oxide fuel cells and dense oxygen permeable membranes

    OpenAIRE

    Faaland, Sonia

    2000-01-01

    Solid oxide fuel cells and oxygen permeable membranes have received considerable attention during the last decade due to the increasing demand for electrical energy and easily transportable fuels combined with the requirement of low emission of CO2. This work concentrates on the stability of ceramic interfaces in general, and more specifically to heterophase solid state interfaces related to solid oxide fuel cells and oxygen permeable membranes. Reaction mechanisms are discussed and requireme...

  18. Development, characterization and modeling of interfaces for high efficiency silicon heterojunction solar cells

    OpenAIRE

    Varache, Renaud

    2012-01-01

    The interface between amorphous silicon (a-Si:H) and crystalline silicon (c-Si) is the building block of high efficiency solar cells based on low temperature fabrication processes. Three properties of the interface determine the performance of silicon heterojunction solar cells: band offsets between a-Si:H and c-Si, interface defects and band bending in c-Si. These three points are addressed in this thesis.First, an analytical model for the calculation of the band bending in c-Si is developed...

  19. The atomistic origin of interface confinement and enhanced conversion efficiency in Si nanowire solar cells.

    Science.gov (United States)

    He, Yan; Quan, Jun; Ouyang, Gang

    2016-03-01

    The photoelectric properties of Si nanowires (SiNWs) under interface confinement are investigated based on the atomic-bond-relaxation consideration and the detailed balance principle. An analytical model is developed to elucidate the interface confinement and power conversion efficiency (PCE). It is found that the band curvature and surface barrier height decrease with decreasing size. The interface recombination rate and PCE can be determined by the size, shell thickness and local interface conditions. Our theoretical results show evident improvement in the PCE of SiNWs under interface confinement compared to that of a bare nanowire, highlighting the feasibility of the epitaxial layer as a booster for highly efficient SiNW solar cells. PMID:26883245

  20. Organic Solar Cells Performances Improvement Induced by Interface Buffer Layers

    OpenAIRE

    Bernède, J. C.; Godoy, A.; Cattin, L; Diaz, F. R.; MORSLI, M; Valle, M. A. del

    2010-01-01

    In the last 22 years that have elapsed since the pioneering work of Tang [Tang, Appl. Phys. Lett., 1986], significant improvement in the fundamental understanding and cells construction have led to efficiencies higher than 6%. The new concept of polymer:fullerene BHJ solar cells has allowed dramatic improvements in devices efficiency. It has induced a healthy competition with the multi-heterojunction devices base on small organic molecules, which induces significant progress in both cells fam...

  1. Si nanoparticle interfaces in Si/SiO solar cell materials

    DEFF Research Database (Denmark)

    Kilpeläinen, S.; Kujala, J.; Tuomisto, F.;

    2013-01-01

    Novel solar cell materials consisting of Si nanoparticles embedded in SiO2 layers have been studied using positron annihilation spectroscopy in Doppler broadening mode and photoluminescence. Two positron-trapping interface states are observed after high temperature annealing at 1100 °C. One of the...... states is attributed to the (SiO2/Si bulk) interface and the other to the interface between the Si nanoparticles and SiO2. A small reduction in positron trapping into these states is observed after annealing the samples in N2 atmosphere with 5% H2. Enhanced photoluminescence is also observed from the...

  2. Design and Evaluation of Cell Phone Pointing Interface for Robot Control

    OpenAIRE

    Saso Koceski; Natasa Koceska; Ivica Kocev

    2012-01-01

    In this work a pointing interface based on human gestures using a mobile phone accelerometer for interaction with robots is proposed. Through this interface the user can sketch stroke gestures on a computer screen using the cell phone accelerometer to make a selection and instruct a robot to perform a task. Selection, cancelation and movement, as well as some additional commands such as stop, pause and resume are supported. All the projected gestures are processed using known image analysis a...

  3. Numerical study of metal oxide hetero-junction solar cells with defects and interface states

    International Nuclear Information System (INIS)

    Further to our previous work on ideal metal oxide (MO) hetero-junction solar cells, a systematic simulation has been carried out to investigate the effects of defects and interface states on the cells. Two structures of the window/absorber (WA) and window/absorber/voltage-enhancer (WAV) were modelled with defect concentration, defect energy level, interface state (ISt) density and ISt energy level as parameters. The simulation showed that the defects in the window layer and the voltage-enhancer layer have very limited effects on the performance of the cells, but those in the absorption layer have profound effects on the cell performance. The interface states at the W/A interface have a limited effect on the performance even for a density up to 1013 cm−2, while those at the A/V interface cause the solar cell to deteriorate severely even at a low density of lower than 1 × 1011 cm−2. It also showed that the back surface field (BSF) induced by band gap off-set in the WAV structure loses its function when defects with a modest concentration exist in the absorption layer and does not improve the open voltage at all. (paper)

  4. Mapping proteolytic cancer cell-extracellular matrix interfaces.

    NARCIS (Netherlands)

    Wolf, K.A.; Friedl, P.H.A.

    2009-01-01

    For cancer progression and metastatic dissemination, cancer cells migrate and penetrate through extracellular tissues. Cancer invasion is frequently facilitated by proteolytic processing of components of the extracellular matrix (ECM). The cellular regions mediating proteolysis are diverse and depen

  5. Air-Liquide 1.8 K refrigeration units for CERN LHC project

    CERN Document Server

    Hilbert, B; Caillaud, A

    2002-01-01

    The Large Hadron Collider (LHC) will be CERN's next research instrument for high energy physics. This 27 km long circular accelerator will make intensive use of superconducting magnets, operated below 2.0 K. It will thus require high capacity refrigeration below 2.0 K. Coupled to a refrigerator providing 18 kW equivalent at 4.5 K, these systems will be able to absorb a cryogenic power of 2.4 kW at 1.8 K in nominal conditions. Air Liquide has designed one Cold Compressor System (CCS) pre-series for CERN- preceding 3 more of them (among 8 in total located around the machine). These systems, making use of cryogenic centrifugal compressors in a series arrangement coupled to room temperature screw compressors, are presented. Key components characteristics will be given. (5 refs).

  6. CD1d and invariant NKT cells at the human maternal–fetal interface

    OpenAIRE

    Boyson, Jonathan E.; Rybalov, Basya; Koopman, Louise A.; Exley, Mark; Balk, Steven P.; Racke, Frederick K.; Schatz, Frederick; Masch, Rachel; Wilson, S. Brian; Strominger, Jack L.

    2002-01-01

    Invariant CD1d-restricted natural killer T (iNKT) cells comprise a small, but significant, immunoregulatory T cell subset. Here, the presence of these cells and their CD1d ligand at the human maternal–fetal interface was investigated. Immunohistochemical staining of human decidua revealed the expression of CD1d on both villous and extravillous trophoblasts, the fetal cells that invade the maternal decidua. Decidual iNKT cells comprised 0.48% of the decidual CD3+ T cell population, a frequency...

  7. Effects of the Molybdenum Oxide/Metal Anode Interfaces on Inverted Polymer Solar Cells

    International Nuclear Information System (INIS)

    Inverted polymer solar cells with molybdenum oxide (MoO3) as an anode buffer layer and different metals (Al or Ag) as anodes are studied. It is found that the inverted cell with a top Ag anode demonstrates enhanced charge collection and higher power conversion efficiency (PCE) compared to the cell with a top Al anode. An 18% increment of PCE is obtained by replacing Al with Ag as the top anode. Further studies show that an interfacial dipole pointing from MoO3 to Al is formed at MoO3/Al interfaces due to electron transfer from Al to MoO3 while this phenomenon cannot be observed at MoO3/Ag interfaces. It is speculated that the electric field at the MoO3/Al interface would hinder hole extraction, and hence reduce the short-circuit current

  8. Nanoscopy of cell architecture: The actin-membrane interface

    OpenAIRE

    Ahmed, Sohail

    2011-01-01

    It was light microscopy that first revealed the hidden world of bacteria and the unit of life the “cell.” From these first observations, made in the late 1600s, it has been clear that seeing is an important tool in biology. The merging of the fields of fluorescence and microscopy created the possibility to see subcellular structures and proteins. In the 1990s the use of the confocal microscopes, where cells/tissue could be optically sectioned, further improved the resolution of object visuali...

  9. Engineering the Interface Between Inorganic Materials and Cells

    Energy Technology Data Exchange (ETDEWEB)

    Schaffer, David

    2014-05-31

    To further optimize cell function in hybrid “living materials”, it would be advantageous to render mammalian cells responsive to novel “orthogonal” cues, i.e. signals they would not ordinarily respond to but that can be engineered to feed into defined intracellular signaling pathways. We recently developed an optogenetic method, based on A. thaliana Cry2, for rapid and reversible protein oligomerization in response to blue light. We also demonstrated the ability to use this method to channel the light input into several defined signaling pathways, work that will enhance communication between inorganic devices and living systems.

  10. Sliced Magnetic Polyacrylamide Hydrogel with Cell-Adhesive Microarray Interface: A Novel Multicellular Spheroid Culturing Platform.

    Science.gov (United States)

    Hu, Ke; Zhou, Naizhen; Li, Yang; Ma, Siyu; Guo, Zhaobin; Cao, Meng; Zhang, Qiying; Sun, Jianfei; Zhang, Tianzhu; Gu, Ning

    2016-06-22

    Cell-adhesive properties are of great significance to materials serving as extracellular matrix mimics. Appropriate cell-adhesive property of material interface can balance the cell-matrix interaction and cell-cell interaction and can promote cells to form 3D structures. Herein, a novel magnetic polyacrylamide (PAM) hydrogel fabricated via combining magnetostatic field induced magnetic nanoparticles assembly and hydrogel gelation was applied as a multicellular spheroids culturing platform. When cultured on the cell-adhesive microarray interface of sliced magnetic hydrogel, normal and tumor cells from different cell lines could rapidly form multicellular spheroids spontaneously. Furthermore, cells which could only form loose cell aggregates in a classic 3D cell culture model (such as hanging drop system) were able to be promoted to form multicellular spheroids on this platform. In the light of its simplicity in fabricating as well as its effectiveness in promoting formation of multicellular spheroids which was considered as a prevailing tool in the study of the microenvironmental regulation of tumor cell physiology and therapeutic problems, this composite material holds promise in anticancer drugs or hyperthermia therapy evaluation in vitro in the future. PMID:27258682

  11. An immersed interface method for the Vortex-In-Cell algorithm

    DEFF Research Database (Denmark)

    Morgenthal, G.; Walther, Jens Honore

    2007-01-01

    The paper presents a two-dimensional immersed interface for the Vortex-In-Cell (VIC) method for simulation of flows past bodies of complex geometry. The particle-mesh VIC algorithm is augmented by a local particle correction term in a Particle-Particle Particle-Mesh (P3M) context to resolve sub......-grid scales incurred by the presence of the immersed interface. The particle-particle correction furthermore allows to disjoin mesh and particle resolution by explicitly resolving sub-grid scales on the paticle. This P3M algorithm uses an influence matrix technique to annihilate the anisotropic sub...... sufficiently distant from the emmersed interfaces, thus maintaining a sufficient spatial representation of the vorticity field. Convergence of the present P3M algorithm is demonstrated for a circulat patch of vorticity. The immersed interface tchnique is applied to the flow past a circular cylinder at a...

  12. Topographical guidance of 3D tumor cell migration at an interface of collagen densities

    International Nuclear Information System (INIS)

    During cancer progression, metastatic cells leave the primary tumor and invade into the fibrous extracellular matrix (ECM) within the surrounding stroma. This ECM network is highly heterogeneous, and interest in understanding how this network can affect cell behavior has increased in the past several decades. However, replicating this heterogeneity has proven challenging. Here, we designed and utilized a method to create a well-defined interface between two distinct regions of high- and low-density collagen gels to mimic the heterogeneities in density found in the tumor stroma. We show that cells will invade preferentially from the high-density side into the low-density side. We also demonstrate that the net cell migration is a function of the density of the collagen in which the cells are embedded, and the difference in density between the two regions has minimal effect on cell net displacement and distance travelled. Our data further indicate that a low-to-high density interface promotes directional migration and induces formation of focal adhesion on the interface surface. Together, the current results demonstrate how ECM heterogeneities, in the form of interfacial boundaries, can affect cell migration. (paper)

  13. Dissecting the interface between signaling and transcriptional regulation in human B cells

    DEFF Research Database (Denmark)

    Wang, Kai; Alvarez, Mariano J; Bisikirska, Brygida C;

    2009-01-01

    manuscript we extend the MINDy algorithm for the identification of posttranslational modulators of transcription factor activity, to produce a first genome-wide map of the interface between signaling and transcriptional regulatory programs in human B cells. We show that the serine-threonine kinase STK38...

  14. Interference-Robust Air Interface for 5G Ultra-dense Small Cells

    DEFF Research Database (Denmark)

    Tavares, Fernando Menezes Leitão; Berardinelli, Gilberto; Mahmood, Nurul Huda;

    2016-01-01

    An ultra-dense deployment of small cells is foreseen as the solution to cope with the exponential increase of the data rate demand targeted by the 5th Generation (5G) radio access technology. In this article, we propose an interference-robust air interface built upon the usage of advanced receivers...

  15. A composite hydrogel platform for the dissection of tumor cell migration at tissue interfaces

    OpenAIRE

    Rape, AD; Kumar, S.

    2014-01-01

    Glioblastoma multiforme (GBM), the most prevalent primary brain cancer, is characterized by diffuse infiltration of tumor cells into brain tissue, which severely complicates surgical resection and contributes to tumor recurrence. The most rapid mode of tissue infiltration occurs along blood vessels or white matter tracts, which represent topological interfaces thought to serve as "tracks" that speed cell migration. Despite this observation, the field lacks experimental paradigms that capture ...

  16. Cell-free biology: exploiting the interface between synthetic biology and synthetic chemistry

    OpenAIRE

    Harris, D. Calvin; Jewett, Michael C.

    2012-01-01

    Just as synthetic organic chemistry once revolutionized the ability of chemists to build molecules (including those that did not exist in nature) following a basic set of design rules, cell-free synthetic biology is beginning to provide an improved toolbox and faster process for not only harnessing but also expanding the chemistry of life. At the interface between chemistry and biology, research in cell-free synthetic systems is proceeding in two different directions: using synthetic biology ...

  17. Operando X-ray Investigation of Electrode/Electrolyte Interfaces in Model Solid Oxide Fuel Cells

    OpenAIRE

    Volkov, Sergey; Vonk, Vedran; Khorshidi, Navid; Franz, Dirk; Kubicek, Markus; Kilic, Volkan; Felici, Roberto; Huber, Tobias M.; Navickas, Edvinas; Rupp, Ghislain M.; Fleig, Jürgen; Stierle, Andreas

    2016-01-01

    We employed operando anomalous surface X-ray diffraction to investigate the buried interface between the cathode and the electrolyte of a model solid oxide fuel cell with atomic resolution. The cell was studied under different oxygen pressures at elevated temperatures and polarizations by external potential control. Making use of anomalous X-ray diffraction effects at the Y and Zr K-edges allowed us to resolve the interfacial structure and chemical composition of a (100)-oriented, 9.5 mol % y...

  18. Counterclockwise Circular Motion of Bacteria Swimming at the Air-Liquid Interface▿ † ‡

    OpenAIRE

    Lemelle, Laurence; Palierne, Jean-François; Chatre, Elodie; Place, Christophe

    2010-01-01

    Flagellar propulsion of swimming Escherichia coli produces circling clockwise motions near planar solid surfaces. Counterclockwise motion was first reported near air-TN medium interfaces, showing that slip at the interface is a key parameter of bacterial swimming.

  19. Picosecond ultrasonics in single cells: Interface step motion for thin animal cells and Brillouin scattering for thick vegetal cells

    Science.gov (United States)

    Ducousso, M.; Dehoux, T.; Audoin, B.; Zouani, O.; Chollet, C.; Durrieu, M. C.

    2011-01-01

    The measurement of the mechanical properties of single biological cells using a picosecond laser-ultrasonic method is proposed. A pump-probe set-up based on ultrafast laser (100 fs pulses) is used to generate and detect acoustic frequencies in the GHz range in a cell on a metallic substrate. The time resolution is about 1 ps and the laser focusing allows a 1 μm lateral resolution. We carry out experiments in both animal and vegetal cells. A semi-analytical simulation model of the physical phenomena involved in experiments is presented. The coupled heat and stress equations are solved including a thermal boundary resistance at the cell/substrate interface and strong acoustic absorption. The optical detection resulting from the interaction between the acoustic wave and the laser light is also modelled. Simulations allow the analysis of experimental signals in both vegetal and animal cells. The results support the potentialities of the non-invasive technique for bioengineering and medical applications.

  20. Overview of Air Liquide refrigeration systems between 1.8 K and 200 K

    International Nuclear Information System (INIS)

    Cryogenic refrigeration systems are necessary for numerous applications. Gas purification and distillation require temperatures between 15 K and 200 K depending on the application, space simulation chambers down to 15 K, superconductivity between 1.8 K and up to 75 K (magnets, cavities or HTS devices like cables, FCL, SMES, etc), Cold Neutron Sources between 15 and 20 K, etc. Air Liquide Advanced Technologies is designing and manufacturing refrigerators since 60 years to satisfy those needs. The step by step developments achieved have led to machines with higher efficiency and reliability. In 1965, reciprocating compressors and Joule Thomson expansion valves were used. In 1969, centripetal expanders began to be used. In 1980, oil lubricated screw compressors took the place of reciprocating compressors and a standard range of Claude cycle refrigerators was developed: the HELIAL series. 1980 was also the time for cryogenic centrifugal compressor development. In 2011, driven by the need for lower operational cost (high efficiency and low maintenance), cycle oil free centrifugal compressors on magnetic bearings were introduced instead of screw compressors. The power extracted by centripetal expanders was recovered. Based on this technology, a range of Turbo-Brayton refrigerators has been designed for temperatures between 40 K and 150 K. On-going development will enable widening the range of Turbo-Brayton refrigerators to cryogenic temperatures down to 15 K.. Cryogenic centrifugal circulators have been developed in order to answer to an increasing demand of 4 K refrigerators able to distribute cold power

  1. Overview of Air Liquide refrigeration systems between 1.8 K and 200 K

    Energy Technology Data Exchange (ETDEWEB)

    Gondrand, C.; Durand, F.; Delcayre, F.; Crispel, S. [AL-AT, 2 rue de Clémencières, 38360 Sassenage (France); Baguer, G. M. Gistau [CRYOGUY, 44, chemin de la Buisse, 38330 Biviers (France)

    2014-01-29

    Cryogenic refrigeration systems are necessary for numerous applications. Gas purification and distillation require temperatures between 15 K and 200 K depending on the application, space simulation chambers down to 15 K, superconductivity between 1.8 K and up to 75 K (magnets, cavities or HTS devices like cables, FCL, SMES, etc), Cold Neutron Sources between 15 and 20 K, etc. Air Liquide Advanced Technologies is designing and manufacturing refrigerators since 60 years to satisfy those needs. The step by step developments achieved have led to machines with higher efficiency and reliability. In 1965, reciprocating compressors and Joule Thomson expansion valves were used. In 1969, centripetal expanders began to be used. In 1980, oil lubricated screw compressors took the place of reciprocating compressors and a standard range of Claude cycle refrigerators was developed: the HELIAL series. 1980 was also the time for cryogenic centrifugal compressor development. In 2011, driven by the need for lower operational cost (high efficiency and low maintenance), cycle oil free centrifugal compressors on magnetic bearings were introduced instead of screw compressors. The power extracted by centripetal expanders was recovered. Based on this technology, a range of Turbo-Brayton refrigerators has been designed for temperatures between 40 K and 150 K. On-going development will enable widening the range of Turbo-Brayton refrigerators to cryogenic temperatures down to 15 K.. Cryogenic centrifugal circulators have been developed in order to answer to an increasing demand of 4 K refrigerators able to distribute cold power.

  2. Overview of Air Liquide refrigeration systems between 1.8 K and 200 K

    Science.gov (United States)

    Gondrand, C.; Durand, F.; Delcayre, F.; Crispel, S.; Baguer, G. M. Gistau

    2014-01-01

    Cryogenic refrigeration systems are necessary for numerous applications. Gas purification and distillation require temperatures between 15 K and 200 K depending on the application, space simulation chambers down to 15 K, superconductivity between 1.8 K and up to 75 K (magnets, cavities or HTS devices like cables, FCL, SMES, etc), Cold Neutron Sources between 15 and 20 K, etc. Air Liquide Advanced Technologies is designing and manufacturing refrigerators since 60 years to satisfy those needs. The step by step developments achieved have led to machines with higher efficiency and reliability. In 1965, reciprocating compressors and Joule Thomson expansion valves were used. In 1969, centripetal expanders began to be used. In 1980, oil lubricated screw compressors took the place of reciprocating compressors and a standard range of Claude cycle refrigerators was developed: the HELIAL series. 1980 was also the time for cryogenic centrifugal compressor development. In 2011, driven by the need for lower operational cost (high efficiency and low maintenance), cycle oil free centrifugal compressors on magnetic bearings were introduced instead of screw compressors. The power extracted by centripetal expanders was recovered. Based on this technology, a range of Turbo-Brayton refrigerators has been designed for temperatures between 40 K and 150 K. On-going development will enable widening the range of Turbo-Brayton refrigerators to cryogenic temperatures down to 15 K.. Cryogenic centrifugal circulators have been developed in order to answer to an increasing demand of 4 K refrigerators able to distribute cold power.

  3. Development of Efficient and Stable Inverted Bulk Heterojunction (BHJ Solar Cells Using Different Metal Oxide Interfaces

    Directory of Open Access Journals (Sweden)

    Ivan Litzov

    2013-12-01

    Full Text Available Solution-processed inverted bulk heterojunction (BHJ solar cells have gained much more attention during the last decade, because of their significantly better environmental stability compared to the normal architecture BHJ solar cells. Transparent metal oxides (MeOx play an important role as the dominant class for solution-processed interface materials in this development, due to their excellent optical transparency, their relatively high electrical conductivity and their tunable work function. This article reviews the advantages and disadvantages of the most common synthesis methods used for the wet chemical preparation of the most relevant n-type- and p-type-like MeOx interface materials consisting of binary compounds AxBy. Their performance for applications as electron transport/extraction layers (ETL/EEL and as hole transport/extraction layers (HTL/HEL in inverted BHJ solar cells will be reviewed and discussed.

  4. Novel power electronic interface for grid-connected fuel cell power generation system

    International Nuclear Information System (INIS)

    Highlights: • A fuel cell power generation system was composed of a DC–DC power converter and a DC–AC inverter. • A voltage doubler based topology was adopted to configure the DC–DC power converter. • A dual buck power converter and a full-bridge power converter were applied to the DC–AC inverter. • The DC–AC inverter outputs a five-level voltage. • The DC–AC inverter performs the functions of DC–AC power conversion and active power filter. - Abstract: A novel power electronic interface for the grid-connected fuel cell power generation system is proposed in this paper. This power electronic interface is composed of a DC–DC power converter and a DC–AC inverter. A voltage doubler based topology is adopted to configure the DC–DC power converter to perform high step-up gain for boosting the output voltage of the fuel cell to a higher voltage. Moreover, the input current ripple of the fuel cell is suppressed by controlling the DC–DC power converter. The DC–AC inverter is configured by a dual buck power converter and a full-bridge power converter to generate a five-level AC output voltage. The DC–AC inverter can perform the functions of DC–AC power conversion and active power filtration. A 1.2 kW hardware prototype is developed to verify the performance of the proposed power electronic interface for the grid-connected fuel cell power generation system. The experimental results show that the proposed power electronic interface for the grid-connected fuel cell power generation system has the expected performance

  5. Polarization Energies at Organic-Organic Interfaces: Impact on the Charge Separation Barrier at Donor-Acceptor Interfaces in Organic Solar Cells.

    Science.gov (United States)

    Ryno, Sean M; Fu, Yao-Tsung; Risko, Chad; Brédas, Jean-Luc

    2016-06-22

    We probe the energetic landscape at a model pentacene/fullerene (C60) interface to investigate the interactions between positive and negative charges, which are critical to the processes of charge separation and recombination in organic solar cells. Using a polarizable force field, we find that polarization energy, i.e., the stabilization a charge feels due to its environment, is larger at the interface than in the bulk for both a positive and a negative charge. The combination of the charge being more stabilized at the interface and the Coulomb attraction between the charges results in a barrier to charge separation at the pentacene/C60 interface that can be in excess of 0.7 eV for static configurations of the donor and acceptor locations. However, the impact of molecular motions, i.e., the dynamics, at the interface at room temperature results in a distribution of polarization energies and in charge separation barriers that can be significantly reduced. The dynamic nature of the interface is thus critical, with the polarization energy distributions indicating that sites along the interface shift in time between favorable and unfavorable configurations for charge separation. PMID:27244215

  6. Polarization Energies at Organic–Organic Interfaces: Impact on the Charge Separation Barrier at Donor–Acceptor Interfaces in Organic Solar Cells

    KAUST Repository

    Ryno, Sean

    2016-05-31

    We probe the energetic landscape at a model pentacene/fullerene-C60 interface to investigate the interactions between positive and negative charges, which are critical to the processes of charge separation and recombination in organic solar cells. Using a polarizable force field, we find that polarization energy, i.e. the stabilization a charge feels due to its environment, is larger at the interface than in the bulk for both a positive and a negative charge. The combination of the charge being more stabilized at the interface and the Coulomb attraction between the charges, results in a barrier to charge separation at the pentacene-C60 interface that can be in excess of 0.7 eV for static configurations of the donor and acceptor locations. However, the impact of molecular motions, i.e., the dynamics, at the interface at room temperature results in a distribution of polarization energies and in charge separation barriers that can be significantly reduced. The dynamic nature of the interface is thus critical, with the polarization energy distributions indicating that sites along the interface shift in time between favorable and unfavorable configurations for charge separation.

  7. A Novel Approach for Ovine Primary Alveolar Epithelial Type II Cell Isolation and Culture from Fresh and Cryopreserved Tissue Obtained from Premature and Juvenile Animals.

    Directory of Open Access Journals (Sweden)

    Mariola M Marcinkiewicz

    Full Text Available The in vivo ovine model provides a clinically relevant platform to study cardiopulmonary mechanisms and treatments of disease; however, a robust ovine primary alveolar epithelial type II (ATII cell culture model is lacking. The objective of this study was to develop and optimize ovine lung tissue cryopreservation and primary ATII cell culture methodologies for the purposes of dissecting mechanisms at the cellular level to elucidate responses observed in vivo. To address this, we established in vitro submerged and air-liquid interface cultures of primary ovine ATII cells isolated from fresh or cryopreserved lung tissues obtained from mechanically ventilated sheep (128 days gestation-6 months of age. Presence, abundance, and mRNA expression of surfactant proteins was assessed by immunocytochemistry, Western Blot, and quantitative PCR respectively on the day of isolation, and throughout the 7 day cell culture study period. All biomarkers were significantly greater from cells isolated from fresh than cryopreserved tissue, and those cultured in air-liquid interface as compared to submerged culture conditions at all time points. Surfactant protein expression remained in the air-liquid interface culture system while that of cells cultured in the submerged system dissipated over time. Despite differences in biomarker magnitude between cells isolated from fresh and cryopreserved tissue, cells isolated from cryopreserved tissue remained metabolically active and demonstrated a similar response as cells from fresh tissue through 72 hr period of hyperoxia. These data demonstrate a cell culture methodology using fresh or cryopreserved tissue to support study of ovine primary ATII cell function and responses, to support expanded use of biobanked tissues, and to further understanding of mechanisms that contribute to in vivo function of the lung.

  8. A Novel Approach for Ovine Primary Alveolar Epithelial Type II Cell Isolation and Culture from Fresh and Cryopreserved Tissue Obtained from Premature and Juvenile Animals.

    Science.gov (United States)

    Marcinkiewicz, Mariola M; Baker, Sandy T; Wu, Jichuan; Hubert, Terrence L; Wolfson, Marla R

    2016-01-01

    The in vivo ovine model provides a clinically relevant platform to study cardiopulmonary mechanisms and treatments of disease; however, a robust ovine primary alveolar epithelial type II (ATII) cell culture model is lacking. The objective of this study was to develop and optimize ovine lung tissue cryopreservation and primary ATII cell culture methodologies for the purposes of dissecting mechanisms at the cellular level to elucidate responses observed in vivo. To address this, we established in vitro submerged and air-liquid interface cultures of primary ovine ATII cells isolated from fresh or cryopreserved lung tissues obtained from mechanically ventilated sheep (128 days gestation-6 months of age). Presence, abundance, and mRNA expression of surfactant proteins was assessed by immunocytochemistry, Western Blot, and quantitative PCR respectively on the day of isolation, and throughout the 7 day cell culture study period. All biomarkers were significantly greater from cells isolated from fresh than cryopreserved tissue, and those cultured in air-liquid interface as compared to submerged culture conditions at all time points. Surfactant protein expression remained in the air-liquid interface culture system while that of cells cultured in the submerged system dissipated over time. Despite differences in biomarker magnitude between cells isolated from fresh and cryopreserved tissue, cells isolated from cryopreserved tissue remained metabolically active and demonstrated a similar response as cells from fresh tissue through 72 hr period of hyperoxia. These data demonstrate a cell culture methodology using fresh or cryopreserved tissue to support study of ovine primary ATII cell function and responses, to support expanded use of biobanked tissues, and to further understanding of mechanisms that contribute to in vivo function of the lung. PMID:26999050

  9. Permissive Schwann Cell Graft/Spinal Cord Interfaces for Axon Regeneration

    OpenAIRE

    Williams, Ryan R.; Henao, Martha; Pearse, Damien D.; Bunge, Mary Bartlett

    2013-01-01

    The transplantation of autologous Schwann cells (SCs) to repair the injured spinal cord is currently being evaluated in a clinical trial. In support, this study determined properties of spinal cord/SC bridge interfaces that enabled regenerated brainstem axons to cross them, possibly leading to improvement in rat hindlimb movement Fluid bridges of SCs and Matrigel were placed in complete spinal cord transections. Compared to pregelled bridges of SCs and Matrigel, they improved regeneration of ...

  10. Transporting of a Cell-Sized Phospholipid Vesicle Across Water/Oil Interface

    OpenAIRE

    Hase, Masahiko; Yamada, Ayako; Hamada, Tsutomu; Yoshikawa, Kenichi

    2006-01-01

    When a cell-sized water droplet, with a diameter of several tens of micro meter, is placed in oil containing phospholipids, a stable cell-sized vesicle is spontaneously formed as a water-in-oil phospholipid emulsion (W/O CE) with a phospholipid monolayer. We transferred the lipid vesicle thus formed in the oil phase to the water phase across the water/oil interface by micromanipulation, which suggests that the vesicle is transformed from a phospholipid monolayer as W/O CE into a bilayer. The ...

  11. Atom-probe tomographic study of interfaces of Cu{sub 2}ZnSnS{sub 4} photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, S., E-mail: e0954@mosk.tytlabs.co.jp; Asahi, R.; Itoh, T.; Hasegawa, M.; Ohishi, K. [Toyota Central R and D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Isheim, D.; Seidman, D. N. [Northwestern University, Evanston, Illinois 60208-3108 (United States)

    2014-09-01

    The heterophase interfaces between the CdS buffer layer and the Cu{sub 2}ZnSnS{sub 4} (CZTS) absorption layers are one of the main factors affecting photovoltaic performance of CZTS cells. We have studied the compositional distributions at heterophase interfaces in CZTS cells using three-dimensional atom-probe tomography. The results demonstrate: (a) diffusion of Cd into the CZTS layer; (b) segregation of Zn at the CdS/CZTS interface; and (c) a change of oxygen and hydrogen concentrations in the CdS layer depending on the heat treatment. Annealing at 573 K after deposition of CdS improves the photovoltaic properties of CZTS cells probably because of the formation of a heterophase epitaxial junction at the CdS/CZTS interface. Conversely, segregation of Zn at the CdS/CZTS interface after annealing at a higher temperature deteriorates the photovoltaic properties.

  12. KGF-transfected cells can stimulate growth and proliferation of human cultured keratinocytes in vitro

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Objective: To establish two stably KGF-transfected, immortalized cell lines. Methods: HaCaT-keratinocytes and KMST-6-fibroblasts were transfected by liposome mediated gene transfer. Transfection effectivity, gene integration and configuration of the transgenic protein were investigated by ELISA, DANN-PCR and β-Gal-staining. Results: Most effective GF producing clones were tested by a colorimetric XTT-test. Conclusion: This is a significant acceleration of cell proliferation and mitosis of human keratinocytes in an Air Liquid Interface (ALI) test system.

  13. A hybrid microfluidic-vacuum device for direct interfacing with conventional cell culture methods

    Directory of Open Access Journals (Sweden)

    Monuki Edwin S

    2007-09-01

    Full Text Available Abstract Background Microfluidics is an enabling technology with a number of advantages over traditional tissue culture methods when precise control of cellular microenvironment is required. However, there are a number of practical and technical limitations that impede wider implementation in routine biomedical research. Specialized equipment and protocols required for fabrication and setting up microfluidic experiments present hurdles for routine use by most biology laboratories. Results We have developed and validated a novel microfluidic device that can directly interface with conventional tissue culture methods to generate and maintain controlled soluble environments in a Petri dish. It incorporates separate sets of fluidic channels and vacuum networks on a single device that allows reversible application of microfluidic gradients onto wet cell culture surfaces. Stable, precise concentration gradients of soluble factors were generated using simple microfluidic channels that were attached to a perfusion system. We successfully demonstrated real-time optical live/dead cell imaging of neural stem cells exposed to a hydrogen peroxide gradient and chemotaxis of metastatic breast cancer cells in a growth factor gradient. Conclusion This paper describes the design and application of a versatile microfluidic device that can directly interface with conventional cell culture methods. This platform provides a simple yet versatile tool for incorporating the advantages of a microfluidic approach to biological assays without changing established tissue culture protocols.

  14. The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells.

    Directory of Open Access Journals (Sweden)

    Nezha Ahmad Agha

    Full Text Available Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys is studied for up to 14 days. Several parameters such as composition of the degradation interface (directly beneath the cells are analysed with a scanning electron microscope equipped with energy dispersive X-ray and focused ion beam. Furthermore, influence of the materials on cell metabolism is examined via different parameters like active mineralisation process. The results are highlighting the influences of the selected alloying element on the initial cells metabolic activity.

  15. Immature, Semi-mature and Fully mature Dendritic Cells: Towards a DC-cancer cells interface that augments anticancer immunity

    Directory of Open Access Journals (Sweden)

    Aleksandra Maria Dudek

    2013-12-01

    Full Text Available Dendritic cells (DCs are the sentinel antigen-presenting cells of the immune system; such that their productive interface with the dying cancer cells is crucial for proper communication of the non-self status of cancer cells to the adaptive immune system. Efficiency and the ultimate success of such a communication hinges upon the maturation status of the DCs, attained following their interaction with cancer cells. Immature DCs facilitate tolerance towards cancer cells (observed for many apoptotic inducers while fully mature DCs can strongly promote anticancer immunity if they secrete the correct combinations of cytokines (observed when DCs interact with cancer cells undergoing immunogenic cell death (ICD. However, an intermediate population of DC maturation, called semi-mature DCs exists, which can potentiate either tolerogenicity or pro-tumourigenic responses (as happens in the case of certain chemotherapeutics and agents exerting ambivalent immune reactions. Specific combinations of DC phenotypic markers, DC-derived cytokines/chemokines, dying cancer cell-derived danger signals and other less characterized entities (e.g. exosomes can define the nature and evolution of the DC maturation state. In the present review, we discuss these different maturation states of DCs, how they might be attained and which anticancer agents or cell death modalities (e.g. tolerogenic cell death vs. ICD may regulate these states.

  16. Interface Engineering of Organic Schottky Barrier Solar Cells and Its Application in Enhancing Performances of Planar Heterojunction Solar Cells

    Science.gov (United States)

    Jin, Fangming; Su, Zisheng; Chu, Bei; Cheng, Pengfei; Wang, Junbo; Zhao, Haifeng; Gao, Yuan; Yan, Xingwu; Li, Wenlian

    2016-05-01

    In this work, we describe the performance of organic Schottky barrier solar cells with the structure of ITO/molybdenum oxide (MoOx)/boron subphthalocyanine chloride (SubPc)/bathophenanthroline (BPhen)/Al. The SubPc-based Schottky barrier solar cells exhibited a short-circuit current density (Jsc) of 2.59 mA/cm2, an open-circuit voltage (Voc) of 1.06 V, and a power conversion efficiency (PCE) of 0.82% under simulated AM1.5 G solar illumination at 100 mW/cm2. Device performance was substantially enhanced by simply inserting thin organic hole transport material into the interface of MoOx and SubPc. The optimized devices realized a 180% increase in PCE of 2.30% and a peak Voc as high as 1.45 V was observed. We found that the improvement is due to the exciton and electron blocking effect of the interlayer and its thickness plays a vital role in balancing charge separation and suppressing quenching effect. Moreover, applying such interface engineering into MoOx/SubPc/C60 based planar heterojunction cells substantially enhanced the PCE of the device by 44%, from 3.48% to 5.03%. Finally, we also investigated the requirements of the interface material for Schottky barrier modification.

  17. Interface Engineering of Organic Schottky Barrier Solar Cells and Its Application in Enhancing Performances of Planar Heterojunction Solar Cells

    Science.gov (United States)

    Jin, Fangming; Su, Zisheng; Chu, Bei; Cheng, Pengfei; Wang, Junbo; Zhao, Haifeng; Gao, Yuan; Yan, Xingwu; Li, Wenlian

    2016-01-01

    In this work, we describe the performance of organic Schottky barrier solar cells with the structure of ITO/molybdenum oxide (MoOx)/boron subphthalocyanine chloride (SubPc)/bathophenanthroline (BPhen)/Al. The SubPc-based Schottky barrier solar cells exhibited a short-circuit current density (Jsc) of 2.59 mA/cm2, an open-circuit voltage (Voc) of 1.06 V, and a power conversion efficiency (PCE) of 0.82% under simulated AM1.5 G solar illumination at 100 mW/cm2. Device performance was substantially enhanced by simply inserting thin organic hole transport material into the interface of MoOx and SubPc. The optimized devices realized a 180% increase in PCE of 2.30% and a peak Voc as high as 1.45 V was observed. We found that the improvement is due to the exciton and electron blocking effect of the interlayer and its thickness plays a vital role in balancing charge separation and suppressing quenching effect. Moreover, applying such interface engineering into MoOx/SubPc/C60 based planar heterojunction cells substantially enhanced the PCE of the device by 44%, from 3.48% to 5.03%. Finally, we also investigated the requirements of the interface material for Schottky barrier modification. PMID:27185635

  18. The Phase Transition of Nematic Liquid Crystal Cells Bounded by Surfactant-Laden Interfaces

    International Nuclear Information System (INIS)

    Taking into account the surface-coupling strength effect, we discuss the phase transitions of a finite thickness cell bounded by surfactant-laden interfaces in a magnetic field perpendicular to the substrate and it is compared with that of a semi-infinite system. It is found that the larger the thickness, the closer the three-dimensional phase transition surface of the finite system to that of the semi-infinite one. The simulation also shows that when a magnetic field is applied to a nematic semi-infinite sample, an orientational phase transition first takes place close to the interface and then extends to the inner space as the temperature increases. (condensed matter: structure, mechanical and thermal properties)

  19. A composite hydrogel platform for the dissection of tumor cell migration at tissue interfaces.

    Science.gov (United States)

    Rape, Andrew D; Kumar, Sanjay

    2014-10-01

    Glioblastoma multiforme (GBM), the most prevalent primary brain cancer, is characterized by diffuse infiltration of tumor cells into brain tissue, which severely complicates surgical resection and contributes to tumor recurrence. The most rapid mode of tissue infiltration occurs along blood vessels or white matter tracts, which represent topological interfaces thought to serve as "tracks" that speed cell migration. Despite this observation, the field lacks experimental paradigms that capture key features of these tissue interfaces and allow reductionist dissection of mechanisms of this interfacial motility. To address this need, we developed a culture system in which tumor cells are sandwiched between a fibronectin-coated ventral surface representing vascular basement membrane and a dorsal hyaluronic acid (HA) surface representing brain parenchyma. We find that inclusion of the dorsal HA surface induces formation of adhesive complexes and significantly slows cell migration relative to a free fibronectin-coated surface. This retardation is amplified by inclusion of integrin binding peptides in the dorsal layer and expression of CD44, suggesting that the dorsal surface slows migration through biochemically specific mechanisms rather than simple steric hindrance. Moreover, both the reduction in migration speed and assembly of dorsal adhesions depend on myosin activation and the stiffness of the ventral layer, implying that mechanochemical feedback directed by the ventral layer can influence adhesive signaling at the dorsal surface. PMID:25047626

  20. Regeneration of tracheal epithelium using mouse induced pluripotent stem cells.

    Science.gov (United States)

    Ikeda, Masakazu; Imaizumi, Mitsuyoshi; Yoshie, Susumu; Otsuki, Koshi; Miyake, Masao; Hazama, Akihiro; Wada, Ikuo; Omori, Koichi

    2016-04-01

    Conclusion The findings demonstrated the potential use of induced pluripotent stem cells for regeneration of tracheal epithelium. Objective Autologous tissue implantation techniques using skin or cartilage are often applied in cases of tracheal defects with laryngeal inflammatory lesions and malignant tumor invasion. However, these techniques are invasive with an unstable clinical outcome. The purpose of this study was to investigate regeneration in a tracheal defect site of nude rats after implantation of ciliated epithelium that was differentiated from induced pluripotent stem cells. Method Embryoid bodies were formed from mouse induced pluripotent stem cells. They were cultured with growth factors for 5 days, and then cultured at the air-liquid interface. The degree of differentiation achieved prior to implantation was determined by histological findings and the results of real-time polymerase chain reaction. Embryoid bodies including ciliated epithelium were embedded into collagen gel that served as an artificial scaffold, and then implanted into nude rats, creating an 'air-liquid interface model'. Histological evaluation was performed 7 days after implantation. Results The ciliated epithelial structure survived on the lumen side of regenerated tissue. It was demonstrated histologically that the structure was composed of ciliated epithelial cells. PMID:26755348

  1. Temperature-responsive intelligent interfaces for biomolecular separation and cell sheet engineering.

    Science.gov (United States)

    Nagase, Kenichi; Kobayashi, Jun; Okano, Teruo

    2009-06-01

    Temperature-responsive intelligent surfaces, prepared by the modification of an interface with poly(N-isopropylacrylamide) and its derivatives, have been used for biomedical applications. Such surfaces exhibit temperature-responsive hydrophilic/hydrophobic alterations with external temperature changes, which, in turn, result in thermally modulated interactions with biomolecules and cells. In this review, we focus on the application of these intelligent surfaces to chromatographic separation and cell cultures. Chromatographic separations using several types of intelligent surfaces are mentioned briefly, and various effects related to the separation of bioactive compounds are discussed, including wettability, copolymer composition and graft polymer architecture. Similarly, we also summarize temperature-responsive cell culture substrates that allow the recovery of confluent cell monolayers as contiguous living cell sheets for tissue-engineering applications. The key factors in temperature-dependent cell adhesion/detachment control are discussed from the viewpoint of grafting temperature-responsive polymers, and new methodologies for effective cell sheet culturing and the construction of thick tissues are summarized. PMID:19324682

  2. Interface characterization of nanometer scale CdS buffer layer in chalcopyrite solar cell

    Science.gov (United States)

    Lin, Shih-Hung; Cheng, Tzu-Huan

    2016-06-01

    The buffer layer of a chalcopyrite solar cell plays an important role in optical responses of open circuit voltage (V oc) and short circuit current (J sc). A CdS buffer layer is applicable on the nanometer scale owing to its high carrier concentration and n-type semiconductor behavior in chalcopyrite solar cells. The thin buffer layer also contributes to the passivation of the absorber surface to reduce defect recombination loss. Non-destructive metrological parameters such as photoluminescence (PL) intensity, external quantum efficiency (EQE), and depth-resolved photovoltage are used to characterize the interface quality of CdS/chalcopyrite. The defects and dangling bonds at the absorber surface will cause interface recombination and reduce the cell performance in build-in voltage distribution. Post annealing can improve Cd ion diffusion from the buffer layer to the absorber surface and reduce the density of defects and dangling bonds. After thermal annealing, the EQE, PL intensity, and minority carrier lifetime are improved.

  3. Similarity of coupled heat and mass transfer between air-water and air-liquid desiccant direct-contact systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiao-Hua; Jiang, Yi [Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084 (China); Li, Zhen [Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China)

    2009-12-15

    Packed-bed heat and mass transfer devices are widely used in air-conditioning systems, such as cooling tower, evaporative cooler of air-water direct-contact devices, dehumidifier and regenerator of air-liquid desiccant direct-contact devices. Similarities of heat and mass transfer characteristics between air-water and air-liquid desiccant devices are considered and investigated in this paper. Same reachable handling region of outlet air can be obtained for both air-water and air-liquid desiccant devices, which is among three boundary lines, isenthalpic line of inlet air, iso-relative humidity line of inlet fluid (water or desiccant), and the connecting line of inlet statuses of air and fluid. Inlet conditions of air and fluid affect heat and mass transfer characteristics to some extent, so that a zonal method is proposed only according to the relative statuses of inlet air to inlet fluid. Four zones, dehumidification zones A, D and regeneration zones B, C, are divided for air-desiccant direct-contact devices. The first three zones A, B and C are divided for air-water direct-contact devices, with the same zonal properties as those of air-desiccant devices. In order to obtain better humidification performance, fluid should be heated (in zone C) rather than air (in zone B). And fluid should be cooled (in zone A) rather than air (in zone D) to obtain better dehumidification performance. Counter-flow pattern should be applied for best mass transfer performance in the same conditions within the recommended zone A or C, while parallel-flow pattern is the best in zone B or D. (author)

  4. Permissive Schwann cell graft/spinal cord interfaces for axon regeneration.

    Science.gov (United States)

    Williams, Ryan R; Henao, Martha; Pearse, Damien D; Bunge, Mary Bartlett

    2015-01-01

    The transplantation of autologous Schwann cells (SCs) to repair the injured spinal cord is currently being evaluated in a clinical trial. In support, this study determined properties of spinal cord/SC bridge interfaces that enabled regenerated brainstem axons to cross them, possibly leading to improvement in rat hindlimb movement. Fluid bridges of SCs and Matrigel were placed in complete spinal cord transections. Compared to pregelled bridges of SCs and Matrigel, they improved regeneration of brainstem axons across the rostral interface. The regenerating brainstem axons formed synaptophysin(+) bouton-like terminals and contacted MAP2A(+) dendrites at the caudal interface. Brainstem axon regeneration was directly associated with glial fibrillary acidic protein (GFAP(+)) astrocyte processes that elongated into the SC bridge. Electron microscopy revealed that axons, SCs, and astrocytes were enclosed together within tunnels bounded by a continuous basal lamina. Neuroglycan (NG2) expression was associated with these tunnels. One week after injury, the GFAP(+) processes coexpressed nestin and brain lipid-binding protein, and the tips of GFAP(+)/NG2(+) processes extended into the bridges together with the regenerating brainstem axons. Both brainstem axon regeneration and number of GFAP(+) processes in the bridges correlated with improvement in hindlimb locomotion. Following SCI, astrocytes may enter a reactive state that prohibits axon regeneration. Elongation of astrocyte processes into SC bridges, however, and formation of NG2(+) tunnels enable brainstem axon regeneration and improvement in function. It is important for spinal cord repair to define conditions that favor elongation of astrocytes into lesions/transplants. PMID:24152553

  5. Probing the PEDOT:PSS/cell interface with conductive colloidal probe AFM-SECM

    Science.gov (United States)

    Knittel, P.; Zhang, H.; Kranz, C.; Wallace, G. G.; Higgins, M. J.

    2016-02-01

    Conductive colloidal probe Atomic Force-Scanning Electrochemical Microscopy (AFM-SECM) is a new approach, which employs electrically insulated AFM probes except for a gold-coated colloid located at the end of the cantilever. Hence, force measurements can be performed while biasing the conductive colloid under physiological conditions. Moreover, such colloids can be modified by electrochemical polymerization resulting, e.g. in conductive polymer-coated spheres, which in addition may be loaded with specific dopants. In contrast to other AFM-based single cell force spectroscopy measurements, these probes allow adhesion measurements at the cell-biomaterial interface on multiple cells in a rapid manner while the properties of the polymer can be changed by applying a bias. In addition, spatially resolved electrochemical information e.g., oxygen reduction can be obtained simultaneously. Conductive colloid AFM-SECM probes modified with poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) are used for single cell force measurements in mouse fibroblasts and single cell interactions are investigated as a function of the applied potential.Conductive colloidal probe Atomic Force-Scanning Electrochemical Microscopy (AFM-SECM) is a new approach, which employs electrically insulated AFM probes except for a gold-coated colloid located at the end of the cantilever. Hence, force measurements can be performed while biasing the conductive colloid under physiological conditions. Moreover, such colloids can be modified by electrochemical polymerization resulting, e.g. in conductive polymer-coated spheres, which in addition may be loaded with specific dopants. In contrast to other AFM-based single cell force spectroscopy measurements, these probes allow adhesion measurements at the cell-biomaterial interface on multiple cells in a rapid manner while the properties of the polymer can be changed by applying a bias. In addition, spatially resolved electrochemical

  6. Impedance and Interface Properties of Al/Methyl-Red/p-In P Solar Cell

    International Nuclear Information System (INIS)

    An Al/methyl-red/p-In P solar cell was fabricated via solution-processing method and was characterized by using current-voltage (I-V) and capacitance-voltage-frequency (C-V-f) measurements at room temperature. From dark I-V characteristics, the values of ideality factor and barrier height of the device were calculated as 1.11 eV and 2.02, respectively. It has been seen that the device exhibited a good photovoltaic behavior with a maximum open circuit voltage Voc of 0.38 V and short-circuit current Isc of 2.8 nA under only 200 lx light intensity. The barrier height and acceptor carrier concentration values for the Al/methyl-red/p-InP devices were extracted as 1.27 eV and 3.46 x1017cm-3 from linear region of its C-2-V characteristics, respectively. The difference between Fb (I-V) and Fb (C-V) for Al/methyl-red/p-InP device was attributed the different nature of the I-V and C-V measurements. Also, the energy distribution curves of the interface states and their time constants were obtained from the experimental conductance properties of the Al/methyl-red/p-InP structure at room temperature. The interface state densities and their relaxation times of the device have ranged from 2.96x1012 cm-2eV-1 and 4.96x10-6 s at (1.11-Ev) eV to 5.19x1012 cm-2 eV-1 and 9.39x10-6 s at (0.79-Ev) eV, respectively. It was seen that both the interface state density and the relaxation time of the interface states have decreased with bias voltage from experimental results

  7. Surface and interface characterization of thin-film silicon solar cell structures

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, Dominic

    2013-02-21

    The properties of Si thin films for solar cells, the interaction with different substrates and the influence of dopants are examined with synchrotron based x-ray spectroscopy - primarily X-ray emission spectroscopy (XES) and hard X-ray photoelectron spectroscopy (HAXPES). The films are studied as-deposited (i.e., amorphous, a-Si) and after conversion into polycrystalline (poly-Si) employing solid phase crystallization (SPC). Si L{sub 2,3} XES spectra of thin-film Si samples can be described by a superposition of a-Si and monocrystalline Si-wafer (c-Si) reference spectra. According to a quantification based on that superposition principle, none of the investigated samples are completely crystallized - a measurable a-Si component always remains (5-20 %) regardless of deposition and treatment conditions. Based on additional results from electron back scattering diffraction different models are developed which may explain this finding. According to these models, the remnant a-Si component can be attributed to amorphous/disordered material at the grain boundaries. Using one of these models, the thickness of this grain-surrounding material s could be approximated to be (1.5 {+-} 0.5) nm. Further investigations of the SPC process reveal a faster crystallization for boron-doped samples, and a slower crystallization for phosphorous-doped samples, when compared to the crystallization of undoped a Si:H thin films. The peculiarities of B K XES spectra (and observed changes upon SPC) indicate that boron could act as a nucleation center promoting crystallization. Si L{sub 2,3} XES spectra of a-Si:H and P-doped poly-Si exhibit spectral features above the valence band maximum at 100 eV that could be attributed to a-Si defect states and n{sup +}-dopant states, respectively. The SPC crystallization velocity of Si thin films on ZnO:Al/glass is found to be faster than that on SiNx/glass substrate. Multiple indications for oxidization at the poly-Si/ZnO:Al interface are found based on

  8. Towards active microfluidics: Interface turbulence in thin liquid films with floating molecular machines

    OpenAIRE

    Alonso, S.; Mikhailov, A.

    2009-01-01

    Thin liquid films with floating active protein machines are considered. Cyclic mechanical motions within the machines, representing microscopic swimmers, lead to molecular propulsion forces applied to the air-liquid interface. We show that, when the rate of energy supply to the machines exceeds a threshold, the flat interface becomes linearly unstable. As the result of this instability, the regime of interface turbulence, characterized by irregular traveling waves and propagating machine clus...

  9. A futuristic approach towards interface layer modifications for improved efficiency in inverted organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, J. P., E-mail: jai-ti2002@yahoo.com, E-mail: tiwarijp@mail.nplindia.org; Ali, Farman; Sharma, Abhishek; Chand, Suresh [Physics of Energy Harvesting Division (Organic and Hybrid Solar Cell Group), CSIR-National Physical Laboratory, CSIR-Network of Institutes for Solar Energy (NISE), Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Pillai, Sriraj; Parakh, Sonal [Physics of Energy Harvesting Division (Organic and Hybrid Solar Cell Group), CSIR-National Physical Laboratory, CSIR-Network of Institutes for Solar Energy (NISE), Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Department of Physics, Delhi Technological University, Bawana Road, Delhi 110042 (India)

    2014-01-27

    Inverted polymer Solar Cells of the classical poly (3-hexylthiophene) (P3HT):(6,6)-phenyl-C{sub 61}butyric acid methyl ester (PC{sub 61}BM) blend on indium tin oxide substrates were fabricated, which shows improved device performance, by using a facile solution–processed ZnO-polyelectrolytes [poly (diallyldimethylammonium chloride) (PDADMAC), Poly (acrylic acid sodium salt) (PAS), poly (4-styrenesulfonic acid) (PSS), and Polyvinylpyrrolidone (PVP)] nanocomposite as a cathode interface layer compared to devices using pristine ZnO as cathode buffer layer in ambient conditions. The devices with different combinations of polyelectrolyte with ZnO show different improvements in the device efficiency. The combinations of ZnO with PVP and PDADMAC show highest amount of improvements in the efficiency by a factor of ∼17–19. The improvement of the efficiency may be due to various phenomena, such as the passivation of ZnO surface as well as bulk traps, work function modification, improved energy level alignment, improved electronic coupling of the inorganic/organic interface, improved light harvesting, and decrease of surface as well as bulk charge recombination in the device. The introduction of polyelectrolyte into ZnO inhibits the aggregation of ZnO nanoparticles yielding the large area ZnO nanoclusters; and hence, forming the uniform film of ZnO resulting in the modifications of morphology as well as electronic structure of ZnO-polyelectrolyte nano-composite favouring better electronic coupling between cathode and active layer and hence enhancing the current and, consequently, the efficiency. This simple low temperature ZnO-polyelectrolyte nanocomposite based protocol proposed for cathode interface layer modification may be very much useful for roll to roll industrial manufacturing of organic solar cells.

  10. A futuristic approach towards interface layer modifications for improved efficiency in inverted organic solar cells

    International Nuclear Information System (INIS)

    Inverted polymer Solar Cells of the classical poly (3-hexylthiophene) (P3HT):(6,6)-phenyl-C61butyric acid methyl ester (PC61BM) blend on indium tin oxide substrates were fabricated, which shows improved device performance, by using a facile solution–processed ZnO-polyelectrolytes [poly (diallyldimethylammonium chloride) (PDADMAC), Poly (acrylic acid sodium salt) (PAS), poly (4-styrenesulfonic acid) (PSS), and Polyvinylpyrrolidone (PVP)] nanocomposite as a cathode interface layer compared to devices using pristine ZnO as cathode buffer layer in ambient conditions. The devices with different combinations of polyelectrolyte with ZnO show different improvements in the device efficiency. The combinations of ZnO with PVP and PDADMAC show highest amount of improvements in the efficiency by a factor of ∼17–19. The improvement of the efficiency may be due to various phenomena, such as the passivation of ZnO surface as well as bulk traps, work function modification, improved energy level alignment, improved electronic coupling of the inorganic/organic interface, improved light harvesting, and decrease of surface as well as bulk charge recombination in the device. The introduction of polyelectrolyte into ZnO inhibits the aggregation of ZnO nanoparticles yielding the large area ZnO nanoclusters; and hence, forming the uniform film of ZnO resulting in the modifications of morphology as well as electronic structure of ZnO-polyelectrolyte nano-composite favouring better electronic coupling between cathode and active layer and hence enhancing the current and, consequently, the efficiency. This simple low temperature ZnO-polyelectrolyte nanocomposite based protocol proposed for cathode interface layer modification may be very much useful for roll to roll industrial manufacturing of organic solar cells

  11. New trends in enzyme immobilization at nanostructured interfaces for efficient electrocatalysis in biofuel cells

    International Nuclear Information System (INIS)

    Biofuel cells, and among them enzymatic biofuel cells, are expected to take part in a sustainable economy in a next future. The development of such biodevices requires significant improvements in terms of efficiency of enzyme immobilization at the electrodes, so as to enable direct electron transfer, and to increase and stabilize the current densities. Many works during the last years aimed at reaching higher current densities, thus power densities, while increasing the long term stability of the enzymatic bioelectrodes. Search for new enzymes, wild type or mutants, new entrapment procedures, but also new electrode architectures, have been targeted. This review focuses on the materials developed and involved during the last few years to meet these demands via nanostructuration of electrode interfaces. Discussion is essentially focused on cases where direct electron transfer between enzymes and electrochemical interfaces are involved. After having introduced the main reasons for the need of nanostructuration, the materials and methods that are newly developed are described. The consequences on improved performances for enzymatic bioelectrodes are discussed, and finally major challenges for future research are addressed

  12. Transporting of a Cell-Sized Phospholipid Vesicle Across Water/Oil Interface

    CERN Document Server

    Hase, M; Hamada, T; Yoshikawa, K; Hase, Masahiko; Yamada, Ayako; Hamada, Tsutomu; Yoshikawa, Kenichi

    2006-01-01

    When a cell-sized water droplet, with a diameter of several tens of micro meter, is placed in oil containing phospholipids, a stable cell-sized vesicle is spontaneously formed as a water-in-oil phospholipid emulsion (W/O CE) with a phospholipid monolayer. We transferred the lipid vesicle thus formed in the oil phase to the water phase across the water/oil interface by micromanipulation, which suggests that the vesicle is transformed from a phospholipid monolayer as W/O CE into a bilayer. The lipid vesicle can then be transported back into the oil phase. This novel experimental procedure may be a useful tool for creating a model cellular system, which, together with a microreactor, is applicable as a micrometer-scale biochemical reaction field.

  13. A Janus-paper PDMS platform for air–liquid interface cell culture applications

    International Nuclear Information System (INIS)

    A commercially available Janus paper with one hydrophobic (polyethylene-coated) face and a hygroscopic/hydrophilic one is irreversibly bonded to a polydimethylsiloxane (PDMS) substrate incorporating microfluidic channels via corona discharge surface treatment. The bond strength between the polymer-coated side and PDMS is characterized as a function of corona treatment time and annealing temperature/time. A maximum strength of 392 kPa is obtained with a 2 min corona treatment followed by 60 min of annealing at 120 °C. The water contact angle of the corona-treated polymer side decreases with increased discharge duration from 98° to 22°. The hygroscopic/hydrophilic side is seeded with human lung fibroblast cells encapsulated in a methacrylated gelatin (GelMA) hydrogel to show the potential of this technology for nutrient and chemical delivery in an air–liquid interface cell culture. (paper)

  14. KCN Chemical Etch for Interface Engineering in Cu2ZnSnSe4 Solar Cells.

    Science.gov (United States)

    Buffière, Marie; Brammertz, Guy; Sahayaraj, Sylvester; Batuk, Maria; Khelifi, Samira; Mangin, Denis; El Mel, Abdel-Aziz; Arzel, Ludovic; Hadermann, Joke; Meuris, Marc; Poortmans, Jef

    2015-07-15

    The removal of secondary phases from the surface of the kesterite crystals is one of the major challenges to improve the performances of Cu2ZnSn(S,Se)4 (CZTSSe) thin film solar cells. In this contribution, the KCN/KOH chemical etching approach, originally developed for the removal of CuxSe phases in Cu(In,Ga)(S,Se)2 thin films, is applied to CZTSe absorbers exhibiting various chemical compositions. Two distinct electrical behaviors were observed on CZTSe/CdS solar cells after treatment: (i) the improvement of the fill factor (FF) after 30 s of etching for the CZTSe absorbers showing initially a distortion of the electrical characteristic; (ii) the progressive degradation of the FF after long treatment time for all Cu-poor CZTSe solar cell samples. The first effect can be attributed to the action of KCN on the absorber, that is found to clean the absorber free surface from most of the secondary phases surrounding the kesterite grains (e.g., Se0, CuxSe, SnSex, SnO2, Cu2SnSe3 phases, excepting the ZnSe-based phases). The second observation was identified as a consequence of the preferential etching of Se, Sn, and Zn from the CZTSe surface by the KOH solution, combined with the modification of the alkali content of the absorber. The formation of a Cu-rich shell at the absorber/buffer layer interface, leading to the increase of the recombination rate at the interface, and the increase in the doping of the absorber layer after etching are found to be at the origin of the deterioration of the FF of the solar cells. PMID:26039042

  15. Particles dispersion on fluid-liquid interfaces

    Institute of Scientific and Technical Information of China (English)

    Sathish Gurupatham; Bhavin Dalal; Md. Shahadat Hossain; Ian S. Fischer; Pushpendra Singh; Daniel D. Joseph

    2011-01-01

    This paper is concerned with the dispersion of particles on the fluid-liquid interface. In a previous study we have shown that when small particles,e.g.,flour,pollen,glass beads,etc.,contact an air-liquid interface,they disperse rapidly as ifthey were in an explosion. The rapid dispersion is due to the fact that the capillary force pulls particles into the interface causing them to accelerate to a large velocity. In this paper we show that motion of particles normal to the interface is inertia dominated: they oscillate vertically about their equilibrium position before coming to rest under viscous drag. This vertical motion of a particle causes a radially-outward lateral (secondary) flow on the interface that causes nearby particles to move away. The dispersion on a liquid-liquid interface,which is the primary focus of this study,was relatively weaker than on an air-liquid interface,and occurred over a longer period of time. When falling through an upper liquid the particles have a slower velocity than when falling through air because the liquid has a greater viscosity. Another difference for the liquid-liquid interface is that the separation of particles begins in the upper liquid before the particles reach the interface. The rate of dispersion depended on the size of the particles,the densities of the particle and liquids,the viscosities of the liquids involved,and the contact angle. For small particles,partial pinning and hysteresis of the three-phase contact line on the surface of the particle during adsorption on liquid-liquid interfaces was also important. The frequency of oscillation of particles about their floating equilibrium increased with decreasing particle size on both air-water and liquid-liquid interfaces,and the time to reach equilibrium decreased with decreasing particle size. These results are in agreement with our analysis.

  16. Electron density profile at the interfaces of bulk heterojunction solar cells and its implication on the S-kink characteristics

    Science.gov (United States)

    Gusain, Abhay; Singh, Surendra; Chauhan, A. K.; Saxena, Vibha; Jha, P.; Veerender, P.; Singh, Ajay; Varde, P. V.; Basu, Saibal; Aswal, D. K.; Gupta, S. K.

    2016-02-01

    The efficiency of a bulk heterojunction (BHJ) solar cell critically depends upon quality of its interfaces. The imperfect interfaces can lead to S-kink in the current-voltage characteristics that reduce the efficiency of BHJ solar cells. In this letter, using PCDTBT:PCBM based BHJ solar cells, we demonstrate that non-destructive X-ray reflectivity is powerful technique to estimate the electron density profile across the BHJ solar cells. A direct correlation is observed between the enhanced electron density at PEDOT:PSS/PCDTBT:PCBM interface and appearance of S-kink in J-V characteristics, which is also supported by X-ray photoelectron spectroscopy and Kelvin probe measurements.

  17. Immune Cell Targets of Infection at the Tick-Skin Interface during Powassan Virus Transmission.

    Directory of Open Access Journals (Sweden)

    Meghan E Hermance

    Full Text Available Powassan virus (POWV is a tick-borne flavivirus that can result in a severe neuroinvasive disease with 50% of survivors displaying long-term neurological sequelae. Human POWV cases have been documented in Canada, the United States, and Russia. Although the number of reported POWV human cases has increased in the past fifteen years, POWV remains one of the less studied human pathogenic flaviviruses. Ixodes ticks are the vectors for POWV, and the virus is transmitted to a host's skin very early during the tick feeding process. Central to the successful transmission of a tick-borne pathogen are complex interactions between the host immune response and early tick-mediated immunomodulation, all of which initially occur at the skin interface. In our prior work, we examined the cutaneous immune gene expression during the early stages of POWV-infected Ixodes scapularis feeding. The present study serves to further investigate the skin interface by identifying early cell targets of infection at the POWV-infected tick feeding site. An in vivo infection model consisting of POWV-infected ticks feeding on mice for short durations was used in this study. Skin biopsies from the tick feeding sites were harvested at various early time points, enabling us to examine the skin histopathology and detect POWV viral antigen in immune cells present at the tick feeding site. The histopathology from the present study demonstrates that neutrophil and mononuclear cell infiltrates are recruited earlier to the feeding site of a POWV-infected tick versus an uninfected tick. This is the first report demonstrating that macrophages and fibroblasts contain POWV antigens, which suggests that they are early cellular targets of infection at the tick feeding site. These data provide key insights towards defining the complex interactions between the host immune response and early tick-mediated immunomodulation.

  18. Hydrogenases as catalysts for fuel cells: Strategies for efficient immobilization at electrode interfaces

    International Nuclear Information System (INIS)

    Highlights: ► This review examines hydrogenases as suitable biocatalysts for H2/O2 biofuel cells. ► It focuses on a O2, CO and temperature-resistant hydrogenase from Aquifex aeolicus. ► Electrically connected hydrogenase amount increases on carbon nanotube network. ► Hydrogenase orientation at the interface controls the electron transfer process. ► Hydrogenase insertion into liposomes enhances its stability. - Abstract: Hydrogenases are the key enzymes for hydrogen metabolism in many microorganisms. Due to the high efficiency they develop for H2 oxidation, research in the last five years has aimed towards their use as biocatalysts for H2/O2 biofuel cells to replace platinum-based chemical catalysts. We report in this review the major issues that have been addressed in view of the future development of such a novel biotechnological device. This includes enhancing the stability of either the enzyme itself or its immobilization onto conductive supports, increasing the amount of electrically connected enzymes and, finally, controlling hydrogenase orientation at the electrode surface, and hence the electron transfer process. We specifically focus on a particular [NiFe] membrane-bound hydrogenase purified from the hyperthermophilic and microaerophilic bacterium Aquifex aeolicus. This enzyme resists to O2, CO, and high temperatures making it potentially efficient as a biocatalyst. Recent progress in these domains strengthens the credibility of a viable H2/O2 biofuel cell and opens new avenues for biofuel cell design.

  19. Three-Dimensional BC/PEDOT Composite Nanofibers with High Performance for Electrode-Cell Interface.

    Science.gov (United States)

    Chen, Chuntao; Zhang, Ting; Zhang, Qi; Feng, Zhangqi; Zhu, Chunlin; Yu, Yalin; Li, Kangming; Zhao, Mengyao; Yang, Jiazhi; Liu, Jian; Sun, Dongping

    2015-12-30

    There is an increasing need to synthesize biocompatible nanofibers with excellent mechanical and electrical performance for electrochemical and biomedical applications. Here we report a facile approach to prepare electroactive and flexible 3D nanostructured biomaterials with high performance based on bacterial cellulose (BC) nanofibers. Our approach can coat BC nanofibers with poly(3,4-ethylenedioxythiophene) (PEDOT) by in situ interfacial polymerization in a controllable manner. The PEDOT coating thickness is adjustable by the monomer concentration or reaction time during polymerization, producing nanofibers with a total diameter ranging from 30 to 200 nm. This fabrication process also provides a convenient method to tune different parameters such as the average pore size and electrical conductivity on the demands of actual applications. Our experiments have demonstrated that the 3D BC/PEDOT nanofibers exhibit high specific surface area, excellent mechanical properties, electroactive stability, and low cell cytotoxicity. With electrical stimulation, calcium imaging of PC12 neural cells on BC/PEDOT nanofibers has revealed a significant increase in the percentage of cells with higher action potentials, suggesting an enhanced capacitance effect of charge injection. As an attractive solution to the challenge of designing better electrode-cell interfaces, 3D BC/PEDOT nanofibers promise many important applications such as biosensing devices, smart drug delivery systems, and implantable electrodes for tissue engineering. PMID:26550840

  20. Electrochemical behavior of LSCF/GDC interface in symmetric cell: An application in solid oxide fuel cells

    International Nuclear Information System (INIS)

    Highlights: • Symmetric cell has been studied to understand electrode/electrolyte interface. • Powder synthesized at fuel to oxidant ratio of 2 possesses agglomerates of 74 nm. • TPR and TPO exhibit the reduction and oxidation behavior at 860 and 388 °C. • Symmetric cell shows charge transfer resistance of 6.3 Ω cm2 at 550 °C. - Abstract: In present paper, La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF)/Ce0.9Gd0.1O1.95 (GDC)/LSCF structure has been studied to understand electrode/electrolyte interface. The nanocrystalline powder required for screen printing was obtained through solution combustion synthesis with glycine as a fuel. The LSCF powder synthesized at fuel to oxidant ratio of two is calcined at 900 °C as TG–DTA reveals thermal stability only beyond 900 °C. The X-ray diffraction pattern of calcined powder demonstrates rhombohedral perovskite structured LSCF with 27 nm crystallite size. However, dynamic laser scattering shows 0.9 μm sized agglomerates while TEM shows 74 nm particles. For potential application in solid oxide fuel cells, the temperature programmed reduction and oxidation were done on the LSCF. The results exhibit strong reduction and oxidation behavior around 860 and 388 °C, respectively. The cell with LSCF as an electrode shows minimum charge transfer resistance of 6.3 Ω cm2 at 550 °C

  1. Electrochemical behavior of LSCF/GDC interface in symmetric cell: An application in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Jamale, Atul P.; Bhosale, C.H. [Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India); Jadhav, L.D., E-mail: ldjadhav.phy@gmail.com [Department of Physics, Rajaram College, Kolhapur 416004, Maharashtra (India)

    2015-02-25

    Highlights: • Symmetric cell has been studied to understand electrode/electrolyte interface. • Powder synthesized at fuel to oxidant ratio of 2 possesses agglomerates of 74 nm. • TPR and TPO exhibit the reduction and oxidation behavior at 860 and 388 °C. • Symmetric cell shows charge transfer resistance of 6.3 Ω cm{sup 2} at 550 °C. - Abstract: In present paper, La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3−δ} (LSCF)/Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95} (GDC)/LSCF structure has been studied to understand electrode/electrolyte interface. The nanocrystalline powder required for screen printing was obtained through solution combustion synthesis with glycine as a fuel. The LSCF powder synthesized at fuel to oxidant ratio of two is calcined at 900 °C as TG–DTA reveals thermal stability only beyond 900 °C. The X-ray diffraction pattern of calcined powder demonstrates rhombohedral perovskite structured LSCF with 27 nm crystallite size. However, dynamic laser scattering shows 0.9 μm sized agglomerates while TEM shows 74 nm particles. For potential application in solid oxide fuel cells, the temperature programmed reduction and oxidation were done on the LSCF. The results exhibit strong reduction and oxidation behavior around 860 and 388 °C, respectively. The cell with LSCF as an electrode shows minimum charge transfer resistance of 6.3 Ω cm{sup 2} at 550 °C.

  2. Band alignment measurements at heterojunction interfaces in layered thin film solar cells & thermoelectrics

    Science.gov (United States)

    Fang, Fang

    2011-12-01

    Public awareness of the increasing energy crisis and the related serious environmental concerns has led to a significantly growing demand for alternative clean and renewable energy resources. Thin film are widely applied in multiple renewable energy devices owing to the reduced amount of raw materials and increase flexibility of choosing from low-cost candidates, which translates directly into reduced capital cost. This is a key driving force to make renewable technology competitive in the energy market. This thesis is focused on the measurement of energy level alignments at interfaces of thin film structures for renewable energy applications. There are two primary foci: II -VI semiconductor ZnSe/ZnTe thin film solar cells and Bi2Te3/Sb2Te3 thin film structures for thermoelectric applications. In both cases, the electronic structure and energy band alignment at interfaces usually controls the carrier transport behavior and determines the quality of the device. High-resolution photoemission spectroscopy (lab-based XPS & synchrotron-based UPS) was used to investigate the chemical and electronic properties of epitaxial Bi2Te3 and Sb2Te3 thin films, in order to validate the anticipated band alignment at interfaces in Bi 2Te3/Sb2Te3 superlattices as one favoring electron-transmission. A simple, thorough two-step treatment of a chemical etching in dilute hydrochloric acid solution and a subsequent annealing at ˜150°C under ultra-high vacuum environment is established to remove the surface oxides completely. It is an essential step to ensure the measurements on electronic states are acquired on stoichimetric, oxide-free clean surface of Bi 2Te3 and Sb2Te3 films. The direct measurement of valence band offsets (VBO) at a real Sb 2Te3/Bi2Te3 interface is designed based on the Kraut model; a special stacking film structure is prepared intentionally: sufficiently thin Sb2Te3 film on top of Bi2Te 3 that photoelectrons from both of them are collected simultaneously. From a

  3. Animal and plant cell technology: a critical evaluation of the technology/society interface.

    Science.gov (United States)

    Spier, R E

    1998-10-27

    The rate at which technology progresses is dependent on the nature of the technology/society interface. This is a complex interaction which involves the production of people capable of making technical advances, the physical opportunities for the deployment of those trained individuals in this task as well as cultural and social factors which will motivate the innovators to produce the advances we need to maintain the momentum of our continually improving situation. One particular aspect of the social situation which may be singled out for special attention is that of the ethics of the society in which people make and use the products of the innovation process. The ethical aspects of biotechnological activities has commanded a great deal of attention recently both from the professional and societal stake-holders. This paper, therefore examines in some detail the ethical aspects of the technology/society interface as it applies, in particular, to the development of animal and plant cell biotechnology. It focuses on the role of the regulatory agency and on the need for biotechnologists to acquire professional status so that they may develop a more trustworthy relationship with society. PMID:9828457

  4. Estimation of defect activation energy around pn interfaces of Cu(In,Ga)Se2 solar cells using impedance spectroscopy

    Science.gov (United States)

    Sakakura, Hidenori; Itagaki, Masayuki; Sugiyama, Mutsumi

    2016-01-01

    We investigate the defect activation energy around the pn interface of Cu(In,Ga)Se2 (CIGS)-based solar cells using a simple electrochemical impedance spectroscopy. By applying AC and DC voltages to the solar cells, we observed an “inductive” element around the pn interface, which is ignored in conventional deep-level transient spectroscopy or admittance spectroscopy. A defect model is evaluated by proposing an equivalent circuit that includes a positive/negative constant phase element (CPE) to represent the area around the CdS/CIGS interface. By fitting the impedance data, the CPE index and CPE constant show a relationship with the defect activation energy or defect concentration. This result is significant because it may help reveal the defect properties of CIGS solar cells or any other semiconductor devices.

  5. Enhanced photovoltaic performance in TiO2/P3HT hybrid solar cell by interface modification

    International Nuclear Information System (INIS)

    A TiO2/P3HT hybrid solar cell was fabricated by infiltrating P3HT into the pores of TiO2 nanorod arrays. To further enhance the photovoltaic performance, anthracene-9-carboxylic acid was employed to modify the interface of TiO2/P3HT before P3HT was coated. Results revealed that the interface treatment significantly enhances the photovoltaic performance of the cell. The efficiency of the hybrid solar cells reaches 0.28% after interface modification, which is three times higher compared with the un-modified one. We find that except for the increased exciton dissociation efficiency recognized by the previous reports, the suppressing of electron back recombination is another important factor leading to the enhanced photovoltaic performance. (semiconductor materials)

  6. Tubulin and actin interplay at the T cell and Antigen-presenting cell interface

    Directory of Open Access Journals (Sweden)

    Noa B Martín-Cófreces

    2011-07-01

    Full Text Available T cells reorganize their actin and tubulin-based cytoskeletons to provide a physical basis to the immune synapse. However, growing evidence shows that their roles on T cell activation are more dynamic than merely serving as tracks or scaffold for different molecules. The cross-talk between both skeletons may be important for the formation and movement of the lamella at the IS by increasing the adhesion of the T cell to the APC, thus favoring the transport of components towards the plasma membrane and in turn regulating the T-APC intercellular communication. Microtubules and F-actin appear to be essential for the transport of the different signaling microclusters along the membrane, therefore facilitating the propagation of the signal. Finally, they can also be important for regulating the endocytosis, recycling and degradation of the TCR signaling machinery, thus helping both to sustain the activated state and to switch it off.

  7. Impedance and Interface Properties of Al/Methyl-Red/p-InP Solar Cell

    Directory of Open Access Journals (Sweden)

    Ömer Güllü

    2009-01-01

    Full Text Available An Al/methyl-red/p-InP solar cell was fabricated via solution-processing method and was characterized by using current-voltage (I-V and capacitance-voltage-frequency (C-V-f measurements at room temperature. From dark I-V characteristics, the values of ideality factor and barrier height of the device were calculated as 1.11 eV and 2.02, respectively. It has been seen that the device exhibited a good photovoltaic behavior with a maximum open circuit voltage Voc of 0.38 V and short-circuit current Isc of 2.8 nA under only 200 lx light intensity. The barrier height and acceptor carrier concentration values for the Al/methyl-red/p-InP devices were extracted as 1.27 eV and 3.46×1017 cm-3 from linear region of its C-2-V characteristics, respectively. The difference between Φb (I-V and Φb (C-V for Al/methyl-red/p-InP device was attributed the different nature of the I-V and C-V measurements. Also, the energy distribution curves of the interface states and their time constants were obtained from the experimental conductance properties of the Al/methyl-red/p-InP structure at room temperature. The interface state densities and their relaxation times of the device have ranged from 2.96×1012 cm-2eV-1 and 4.96×10-6 s at (1.11-Ev eV to 5.19×1012 cm-2 eV-1 and 9.39×10-6 s at (0.79-Ev eV, respectively. It was seen that both the interface state density and the relaxation time of the interface states have decreased with bias voltage from experimental results.

  8. Parallel macromolecular delivery and biochemical/electrochemical interface to cells employing nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, Timothy E; Melechko, Anatoli V; Griffin, Guy D; Guillorn, Michael A; Merkulov, Vladimir L; Simpson, Michael L

    2015-03-31

    Systems and methods are described for parallel macromolecular delivery and biochemical/electrochemical interface to whole cells employing carbon nanostructures including nanofibers and nanotubes. A method includes providing a first material on at least a first portion of a first surface of a first tip of a first elongated carbon nanostructure; providing a second material on at least a second portion of a second surface of a second tip of a second elongated carbon nanostructure, the second elongated carbon nanostructure coupled to, and substantially parallel to, the first elongated carbon nanostructure; and penetrating a boundary of a biological sample with at least one member selected from the group consisting of the first tip and the second tip.

  9. High efficiency solution processed sintered CdTe nanocrystal solar cells: the role of interfaces.

    Science.gov (United States)

    Panthani, Matthew G; Kurley, J Matthew; Crisp, Ryan W; Dietz, Travis C; Ezzyat, Taha; Luther, Joseph M; Talapin, Dmitri V

    2014-02-12

    Solution processing of photovoltaic semiconducting layers offers the potential for drastic cost reduction through improved materials utilization and high device throughput. One compelling solution-based processing strategy utilizes semiconductor layers produced by sintering nanocrystals into large-grain semiconductors at relatively low temperatures. Using n-ZnO/p-CdTe as a model system, we fabricate sintered CdTe nanocrystal solar cells processed at 350 °C with power conversion efficiencies (PCE) as high as 12.3%. JSC of over 25 mA cm(-2) are achieved, which are comparable or higher than those achieved using traditional, close-space sublimated CdTe. We find that the VOC can be substantially increased by applying forward bias for short periods of time. Capacitance measurements as well as intensity- and temperature-dependent analysis indicate that the increased VOC is likely due to relaxation of an energetic barrier at the ITO/CdTe interface. PMID:24364381

  10. In-operando temperature measurement across the interfaces of a lithium-ion battery cell

    International Nuclear Information System (INIS)

    In this work an experimental setup for in-operando temperature measurements across the interfaces anode – separator/electrolyte – cathode of a lithium-ion battery cell is developed to get a better understanding of the heat generating mechanisms. The results show differences in the heat evolution rates of the anode, the separator and the cathode according to the electrochemical reactions, the state of charge, the overvoltage and the electric current density. The LiCoO2 cathode was identified as the most decisive component for the heat evolution in the investigated battery stack. Changes of the ohmic resistance and the entropy of LiCoO2 with the state of charge were reflected by the temperature measurements

  11. Interface electric properties of Si/organic hybrid solar cells using impedance spectroscopy analysis

    Science.gov (United States)

    Wang, Dan; Zhu, Juye; Ding, Li; Gao, Pingqi; Pan, Xiaoyin; Sheng, Jiang; Ye, Jichun

    2016-05-01

    The internal resistance and capacitance of Si/organic hybrid solar cells (Si-HSC) based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) are investigated by electrochemical impedance spectroscopy (EIS). Three types of Nyquist plots in Si-HSC are observed firstly at different bias voltages, while suitable equivalent circuit models are established to evaluate the details of interface carrier transfer and recombination. In particular, the carrier transport property of the PEDOT:PSS film responds at a high frequency (6 × 104-1 × 106 Hz) in three-arc spectra. Therefore, EIS could help us deeply understand the electronic properties of Si-HSC for developing high performance devices.

  12. ZnO interface layer and CO{sub 2} plasma treatment for improving efficiency of micromorph silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Limmanee, A.; Sriprapha, K.; Sritharathikhun, J.; Piromjit, C. [Institute of Solar Energy Technology Development, National Science and Technology Development Agency, 111 Thailand Science Park, Phahonyothin Road, Klong 1, Klong Luang, Pathumthani 12120 (Thailand)

    2011-01-15

    We have developed zinc oxide (ZnO) film and CO{sub 2} plasma treatment for the use as an intermediate layer between top and bottom cell in order to improve performance of micromorph silicon solar cells. The CO{sub 2} plasma treatment was performed by very high frequency plasma-enhanced chemical vapor deposition (VHF PECVD) technique, and the ZnO interface layer was deposited by DC-magnetron sputtering method. Effects of both techniques on the cell performance were comparatively investigated. We found that the ZnO interface layer and CO{sub 2} plasma treatment were effective in enhancing V{sub oc}, J{sub sc} as well as FF of the cells as the same. The micromorph solar cells using an optimized ZnO interface layer and the CO{sub 2} plasma treatment indicated initial conversion efficiency of 11.4% and 11.2%, respectively. Experimental results indicated that the CO{sub 2} plasma treatment technique is more suitable for using in cell fabrication process than the ZnO interface layer since it is simpler and has no negative impact of possible shunts. (author)

  13. Interface properties of Cd-free buffer layers on on CIGSe thin film solar cells

    International Nuclear Information System (INIS)

    In order to replace the toxic Cadmium, the substitution of the CdS buffer layer in thin film solar cells based on Cu(In,Ga)(S,Se)2 (CIGSSe) is of great interest. Alternative buffer layers like (In,Al)2S3, In2S3, or (Zn1-x,Mgx)O deposited by conventional sputter and chemical bath deposition techniques, have shown efficiencies close to or comparable to those of CdS containing solar cells. To understand the chemical and electronic properties of these buffer layers and its influence on the absorber, we studied the buffer-absorber interface using photoelectron spectroscopy (XPS, UPS) and inverse photoelectron spectroscopy (IPES). The combination of these non-destructive techniques provides detailed information about the chemical properties of the studied surface, as well as can be used for a direct determination of the conduction and valence band alignment at the heterojunction. Band-gap values at the surface as derived by UPS and IPES are also verified by electron energy loss spectroscopy (EELS). The results are discussed in conjunction with the respective cell parameters.

  14. Understanding dielectrophoretic trapping of neuronal cells: modelling electric field, electrode-liquid interface and fluid flow

    International Nuclear Information System (INIS)

    By application of dielectrophoresis neuronal cells can be trapped successfully. Several trapping experiments have been performed using a quadrupole electrode structure at different amplitudes (1, 3, and 5 Vpp) and frequencies (10-50 MHz). Due to the high conductivity of the suspending medium negative dielectrophoretic forces are created. The dielectrophoretic force is determined by the gradient of the electric field. However, the electrode-liquid interfaces are responsible for decreased electric field strengths, and thus decreased field gradients, inside the medium, especially at lower frequencies. Circuit modelling is used to determine the frequency-dependent electric field inside the medium. The creation of an electric field in high conductivity of the medium results in local heating, which in turn induces fluid flow. This flow also drives the neurons and was found to enhance the trapping effect of the dielectrophoretic force. With the use of finite element modelling, this aspect was investigated. The results show that the dielectrophoretic force is dominating just above the substrate. When the upward dielectrophoretic force is large enough to levitate the cells, they may be dragged along with the fluid flow. The result is that more cells may be trapped than expected on the basis of dielectrophoresis alone. (author)

  15. A cell-phone-based brain-computer interface for communication in daily life

    Science.gov (United States)

    Wang, Yu-Te; Wang, Yijun; Jung, Tzyy-Ping

    2011-04-01

    Moving a brain-computer interface (BCI) system from a laboratory demonstration to real-life applications still poses severe challenges to the BCI community. This study aims to integrate a mobile and wireless electroencephalogram (EEG) system and a signal-processing platform based on a cell phone into a truly wearable and wireless online BCI. Its practicality and implications in a routine BCI are demonstrated through the realization and testing of a steady-state visual evoked potential (SSVEP)-based BCI. This study implemented and tested online signal processing methods in both time and frequency domains for detecting SSVEPs. The results of this study showed that the performance of the proposed cell-phone-based platform was comparable, in terms of the information transfer rate, with other BCI systems using bulky commercial EEG systems and personal computers. To the best of our knowledge, this study is the first to demonstrate a truly portable, cost-effective and miniature cell-phone-based platform for online BCIs.

  16. Interface engineering of layer-by-Layer stacked graphene anodes for high-performance organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu; Tong, Shi Wun; Loh, Kian Ping [Department of Chemistry, National University of Singapore (Singapore); Xu, Xiang Fan; Oezyilmaz, Barbaros [Department of Physics, National University of Singapore (Singapore)

    2011-04-05

    An interface engineering process to deploy graphene film as the anode in poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM)-based polymer solar cells is demonstrated. By modifying the interface between the graphene anode and the photoactive layer with MoO{sub 3} and poly(3,4-ethylenedioythiophene):poly(styrenesulfonate) (PEDOT:PSS), the power conversion efficiency of the solar cells reaches {approx}83.3% of control devices that use an indium tin oxide (ITO) anode. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Biofunctionalization of conductive hydrogel coatings to support olfactory ensheathing cells at implantable electrode interfaces.

    Science.gov (United States)

    Hassarati, Rachelle T; Marcal, Helder; John, L; Foster, R; Green, Rylie A

    2016-05-01

    Mechanical discrepancies between conventional platinum (Pt) electrodes and neural tissue often result in scar tissue encapsulation of implanted neural recording and stimulating devices. Olfactory ensheathing cells (OECs) are a supportive glial cell in the olfactory nervous system which can transition through glial scar tissue while supporting the outgrowth of neural processes. It has been proposed that this function can be used to reconnect implanted electrodes with the target neural pathways. Conductive hydrogel (CH) electrode coatings have been proposed as a substrate for supporting OEC survival and proliferation at the device interface. To determine an ideal CH to support OECs, this study explored eight CH variants, with differing biochemical composition, in comparison to a conventional Pt electrodes. All CH variants were based on a biosynthetic hydrogel, consisting of poly(vinyl alcohol) and heparin, through which the conductive polymer (CP) poly(3,4-ethylenedioxythiophene) was electropolymerized. The biochemical composition was varied through incorporation of gelatin and sericin, which were expected to provide cell adherence functionality, supporting attachment, and cell spreading. Combinations of these biomolecules varied from 1 to 3 wt %. The physical, electrical, and biological impact of these molecules on electrode performance was assessed. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrated that the addition of these biological molecules had little significant effect on the coating's ability to safely transfer charge. Cell attachment studies, however, determined that the incorporation of 1 wt % gelatin in the hydrogel was sufficient to significantly increase the attachment of OECs compared to the nonfunctionalized CH. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 104B: 712-722, 2016. PMID:26248597

  18. Endotoxemia-induced cytokine-mediated responses of hippocampal astrocytes transmitted by cells of the brain–immune interface

    Science.gov (United States)

    Hasegawa-Ishii, Sanae; Inaba, Muneo; Umegaki, Hiroyuki; Unno, Keiko; Wakabayashi, Keiji; Shimada, Atsuyoshi

    2016-01-01

    Systemic inflammation shifts the brain microenvironment towards a proinflammatory state. However, how peripheral inflammation mediates changes in the brain remains to be clarified. We aimed to identify hippocampal cells and cytokines that respond to endotoxemia. Mice were intraperitoneally injected with lipopolysaccharide (LPS) or saline, and examined 1, 4, and 24 h after injection. Tissue cytokine concentrations in the spleens and hippocampi were determined by multiplex assays. Another group of mice were studied immunohistologically. Fourteen cytokines showed an increased concentration in the spleen, and 10 showed an increase in the hippocampus after LPS injection. Cytokines increased at 4 h (CCL2, CXCL1, CXCL2, and interleukin-6) were expressed by leptomeningeal stromal cells, choroid plexus stromal cells, choroid plexus epithelial cells, and hippocampal vascular endothelial cells, all of which were located at the brain–immune interface. Receptors for these cytokines were expressed by astrocytic endfeet. Cytokines increased at 24 h (CCL11, CXCL10, and granulocyte-colony stimulating factor) were expressed by astrocytes. Cells of the brain–immune interface therefore respond to endotoxemia with cytokine signals earlier than hippocampal parenchymal cells. In the parenchyma, astrocytes play a key role in responding to signals by using endfeet located in close apposition to the interface cells via cytokine receptors. PMID:27149601

  19. Endotoxemia-induced cytokine-mediated responses of hippocampal astrocytes transmitted by cells of the brain-immune interface.

    Science.gov (United States)

    Hasegawa-Ishii, Sanae; Inaba, Muneo; Umegaki, Hiroyuki; Unno, Keiko; Wakabayashi, Keiji; Shimada, Atsuyoshi

    2016-01-01

    Systemic inflammation shifts the brain microenvironment towards a proinflammatory state. However, how peripheral inflammation mediates changes in the brain remains to be clarified. We aimed to identify hippocampal cells and cytokines that respond to endotoxemia. Mice were intraperitoneally injected with lipopolysaccharide (LPS) or saline, and examined 1, 4, and 24 h after injection. Tissue cytokine concentrations in the spleens and hippocampi were determined by multiplex assays. Another group of mice were studied immunohistologically. Fourteen cytokines showed an increased concentration in the spleen, and 10 showed an increase in the hippocampus after LPS injection. Cytokines increased at 4 h (CCL2, CXCL1, CXCL2, and interleukin-6) were expressed by leptomeningeal stromal cells, choroid plexus stromal cells, choroid plexus epithelial cells, and hippocampal vascular endothelial cells, all of which were located at the brain-immune interface. Receptors for these cytokines were expressed by astrocytic endfeet. Cytokines increased at 24 h (CCL11, CXCL10, and granulocyte-colony stimulating factor) were expressed by astrocytes. Cells of the brain-immune interface therefore respond to endotoxemia with cytokine signals earlier than hippocampal parenchymal cells. In the parenchyma, astrocytes play a key role in responding to signals by using endfeet located in close apposition to the interface cells via cytokine receptors. PMID:27149601

  20. Transcriptome sequencing reveals e-cigarette vapor and mainstream-smoke from tobacco cigarettes activate different gene expression profiles in human bronchial epithelial cells

    OpenAIRE

    Yifei Shen; Michael J. Wolkowicz; Tatyana Kotova; Lonjiang Fan; Timko, Michael P.

    2016-01-01

    Electronic cigarettes (e-cigarettes) generate an aerosol vapor (e-vapor) thought to represent a less risky alternative to main stream smoke (MSS) of conventional tobacco cigarettes. RNA-seq analysis was used to examine the transcriptomes of differentiated human bronchial epithelial (HBE) cells exposed to air, MSS from 1R5F tobacco reference cigarettes, and e-vapor with and without added nicotine in an in vitro air-liquid interface model for cellular exposure. Our results indicate that while e...

  1. Interface Modification of Dye-sensitized Solar Cells with Pivalic Acid to Enhance the Open-circuit Voltage

    KAUST Repository

    Li, Xin

    2009-01-01

    Pivalic acid (PVA) was used as a new coadsorbent to dye-sensitized solar cells (DSCs) to modify the interface between the TiO2 films and electrolyte. The addition of PVA improved the light-to-electricity conversion efficiency of devices by 8% by enhancing the open-circuit voltage. Copyright © 2009 The Chemical Society of Japan.

  2. Combination of fluid and solid mechanical stresses contribute to cell death and detachment in a microfluidic alveolar model.

    Science.gov (United States)

    Douville, Nicholas J; Zamankhan, Parsa; Tung, Yi-Chung; Li, Ran; Vaughan, Benjamin L; Tai, Cheng-Feng; White, Joshua; Christensen, Paul J; Grotberg, James B; Takayama, Shuichi

    2011-02-21

    Studies using this micro-system demonstrated significant morphological differences between alveolar epithelial cells (transformed human alveolar epithelial cell line, A549 and primary murine alveolar epithelial cells, AECs) exposed to combination of solid mechanical and surface-tension stresses (cyclic propagation of air-liquid interface and wall stretch) compared to cell populations exposed solely to cyclic stretch. We have also measured significant differences in both cell death and cell detachment rates in cell monolayers experiencing combination of stresses. This research describes new tools for studying the combined effects of fluid mechanical and solid mechanical stress on alveolar cells. It also highlights the role that surface tension forces may play in the development of clinical pathology, especially under conditions of surfactant dysfunction. The results support the need for further research and improved understanding on techniques to reduce and eliminate fluid stresses in clinical settings. PMID:21152526

  3. Interface engineering of hybrid perovskite solar cells with poly(3-thiophene acetic acid) under ambient conditions.

    Science.gov (United States)

    Shit, Arnab; Nandi, Arun K

    2016-04-21

    The properties of methyl ammonium lead iodide (MAPbI3) perovskite solar cells with poly(3-thiophene acetic acid) (P3TAA) as a hole transporting material (HTM) and a dense layer of ZnO nanoparticle film as an electron transporting material (ETM) are described using the conventional ZnO (n)/perovskite (i)/P3TAA (p) (n-i-p) architecture. The FT-IR spectra of a MAPbI3/P3TAA mixture indicate a shift of the N-H stretching and the abolition of the N-H bending peak indicating the interaction between the components. UV-Vis spectra of the mixture exhibit a large red shift of the π-π* transition peak of the conjugated chain arising from the interaction causing an increase of the conjugation length. The cross-sectional SEM image of the device shows the sequence of the individual layers of ZnO, MAPbI3, P3TAA and Ag, respectively. The current density (J)-voltage (V) curves obtained upon illumination with a light of 100 mW cm(-2) indicate the average PCE to be 7.38 ± 0.59% under ambient conditions. The IPCE values of these cells reach about 63% across a broad range of wavelength (300-800 nm). The HOMO and the LUMO of P3TAA are measured using cyclic voltammetry and the optical band gap and the relative energy level of the components explain the operation of photocurrent in the cell. For comparison purposes a device using poly(3-hexyl thiophene) (P3HT) as the HTM is fabricated under similar conditions and it exhibits a lower PCE (5.85 ± 0.51%) than that of the P3TAA based device. The longevity of the P3TAA based cell is also found to be better than that of the P3HT based cell for storing in air. The UV-Vis and impedance spectral results clearly explain the above results, signifying the influence of the interface on the performance of hybrid solar cells. PMID:27020145

  4. Emulsification efficiency of adsorbed chitosan for bacterial cells accumulation at the oil-water interface.

    Science.gov (United States)

    Archakunakorn, Somwit; Charoenrat, Nattapat; Khamsakhon, Somruethai; Pongtharangkul, Thunyarat; Wongkongkatep, Pravit; Suphantharika, Manop; Wongkongkatep, Jirarut

    2015-04-01

    The use of bacterial cell or biocatalyst for industrial synthetic chemistry is on the way of significant growth since the biocatalyst requires low energy input compared to the chemical synthesis and can be considered as a green technology. However, majority of natural bacterial cell surface is hydrophilic which allows poor access to the hydrophobic substrate or product. In this study, Escherichia coli (E. coli) as a representative of hydrophilic bacterial cells were accumulated at the oil-water interface after association with chitosan at a concentration range of 0.75-750 mg/L. After association with negatively charged E coli having a ζ potential of -19.9 mV, a neutralization of positively charged chitosan occurred as evidenced by an increase in the ζ potential value of the mixtures with increasing chitosan concentration up to +3.5 mV at 750 mg/L chitosan. Both emulsification index and droplet size analysis revealed that chitosan-E. coli system is an excellent emulsion stabilizer to date because the threshold concentration was as low as 7.5 mg/L or 0.00075% w/v. A dramatic increase in the surface hydrophobicity of the E. coli as evidenced by an increase in contact angle from 19 to 88° with increasing chitosan concentration from 0 to 750 mg/L, respectively, resulted in an increase in the stability of oil-in-water emulsions stabilized by chitosan-E. coli system. The emulsion was highly stable even the emulsification was performed under 20% salt condition, or temperature ranged between 20 and 50 °C. Emulsification was failed when the oil volume fraction was higher than 0.5, indicating that no phase inversion occurred. The basic investigation presented in this study is a crucial platform for its application in biocatalyst industry and bioremediation of oil spill. PMID:25341365

  5. Controlling mesenchymal stem cells differentiate into contractile smooth muscle cells on a TiO2 micro/nano interface: Towards benign pericytes environment for endothelialization.

    Science.gov (United States)

    Li, Jingan; Qin, Wei; Zhang, Kun; Wu, Feng; Yang, Ping; He, Zikun; Zhao, Ansha; Huang, Nan

    2016-09-01

    Building healthy and oriented smooth muscle cells (SMCs) environment is an effective method for improving the surface endothelialization of the cardiovascular implants. However, a long-term and stable source of SMCs for implantation without immune rejection and inflammation has not been solved, and mesenchymal stem cells (MSCs) differentiation may be a good choice. In this work, two types of TiO2 micro/nano interfaces were fabricated on titanium surface by photolithography and anodic oxidation. These TiO2 micro/nano interfaces were used to regulate the differentiation of the MSCs. The X-ray diffraction (XRD) detection showed that the TiO2 micro/nano interfaces possessed the anatase crystal structure, suggesting good cytocompatibility. The CCK-8 results indicated the TiO2 micro/nano interfaces improved MSC proliferation, further immunofluorescence staining and calculation of the cell morphology index proved the micro/nano surfaces also elongated MSCs and regulated MSCs oriented growth. The specific staining of α-SMA, CNN-1, vWF, CD44 and CD133 markers revealed that the micro/nano surfaces induced MSCs differentiation to contractile SMCs, and the endothelial cells (ECs) culture experiment indicated that the MSCs induced by micro/nano interfaces contributed to the ECs attachment and proliferation. This method will be further studied and applied for the surface modification of the cardiovascular implants. PMID:27232304

  6. Engineered interfaces and nano-scale thin films for solid oxide fuel cell electrolytes

    Science.gov (United States)

    Nandasiri, Manjula I.

    Solid state electrolytes with high oxygen ionic conductivity at low temperatures are required to develop cost effective and efficient solid oxide fuel cells. This study investigates the influence of engineered interfaces on the oxygen ionic conductivity of nano-scale multilayer thin film electrolytes. The epitaxial Sm2O3 doped CeO2 (SDC) and Sc2O3 stabilized ZrO2 (ScSZ) are selected as the alternative layers for the proposed multilayer thin film electrolyte based on the optimum structural, chemical, and electrical properties reported in the previous studies. The epitaxial SDC(111)/ScSZ(111) multilayer thin films are grown on high purity Al2O3(0001) substrates by oxygen-plasma assisted molecular beam epitaxy. Prior to the deposition of multilayers, the growth parameters are optimized for epitaxial CeO 2, ZrO2, SDC, and ScSZ thin films. The epitaxial orientation and surface morphology of CeO2 thin films shows dependency on the growth rate. Epitaxial CeO2(111) is obtained at relatively high growth rates (>9 A/min) at a substrate temperature of 650°C and an oxygen partial pressure of 2 x 10 -5 Torr. The same growth parameters are used for the deposition of ZrO2 thin films. ZrO2 exhibits both monoclinic and cubic phases, which is stabilized in the cubic structure by doping with Sc 2O3. The Sm and Sc evaporation rates are varied during the growth to obtain thin films of 15 mol % SmO1.5 doped CeO2 and 20 mol % ScO1.5 stabilized ZrO2, respectively. The SDC/ScSZ multilayer thin films are grown using the same growth parameters by varying the number of layers. The SDC/ScSZ multilayer thin films show significant enhancement in the oxygen ionic conductivity in comparison to single layer SDC and ScSZ thin films. The increase in the oxygen ionic conductivity with the increase in number of layers can be attributed to lattice mismatch induced ionic conductivity along the interfaces. The 8-layer film exhibits the maximum oxygen ionic conductivity with one order of magnitude

  7. Sticky water surfaces: helix-coil transitions suppressed in a cell-penetrating peptide at the air-water interface.

    Science.gov (United States)

    Schach, Denise; Globisch, Christoph; Roeters, Steven J; Woutersen, Sander; Fuchs, Adrian; Weiss, Clemens K; Backus, Ellen H G; Landfester, Katharina; Bonn, Mischa; Peter, Christine; Weidner, Tobias

    2014-12-14

    GALA is a 30 amino acid synthetic peptide consisting of a Glu-Ala-Leu-Ala repeat and is known to undergo a reversible structural transition from a disordered to an α-helical structure when changing the pH from basic to acidic values. In its helical state GALA can insert into and disintegrate lipid membranes. This effect has generated much interest in GALA as a candidate for pH triggered, targeted drug delivery. GALA also serves as a well-defined model system to understand cell penetration mechanisms and protein folding triggered by external stimuli. Structural transitions of GALA in solution have been studied extensively. However, cell penetration is an interfacial effect and potential biomedical applications of GALA would involve a variety of surfaces, e.g., nanoparticles, lipid membranes, tubing, and liquid-gas interfaces. Despite the apparent importance of interfaces in the functioning of GALA, the effect of surfaces on the reversible folding of GALA has not yet been studied. Here, we use sum frequency generation vibrational spectroscopy (SFG) to probe the structural response of GALA at the air-water interface and IR spectroscopy to follow GALA folding in bulk solution. We combine the SFG data with molecular dynamics simulations to obtain a molecular-level picture of the interaction of GALA with the air-water interface. Surprisingly, while the fully reversible structural transition was observed in solution, at the water-air interface, a large fraction of the GALA population remained helical at high pH. This "stickiness" of the air-water interface can be explained by the stabilizing interactions of hydrophobic leucine and alanine side chains with the water surface. PMID:25494788

  8. Sticky water surfaces: Helix-coil transitions suppressed in a cell-penetrating peptide at the air-water interface

    Science.gov (United States)

    Schach, Denise; Globisch, Christoph; Roeters, Steven J.; Woutersen, Sander; Fuchs, Adrian; Weiss, Clemens K.; Backus, Ellen H. G.; Landfester, Katharina; Bonn, Mischa; Peter, Christine; Weidner, Tobias

    2014-12-01

    GALA is a 30 amino acid synthetic peptide consisting of a Glu-Ala-Leu-Ala repeat and is known to undergo a reversible structural transition from a disordered to an α-helical structure when changing the pH from basic to acidic values. In its helical state GALA can insert into and disintegrate lipid membranes. This effect has generated much interest in GALA as a candidate for pH triggered, targeted drug delivery. GALA also serves as a well-defined model system to understand cell penetration mechanisms and protein folding triggered by external stimuli. Structural transitions of GALA in solution have been studied extensively. However, cell penetration is an interfacial effect and potential biomedical applications of GALA would involve a variety of surfaces, e.g., nanoparticles, lipid membranes, tubing, and liquid-gas interfaces. Despite the apparent importance of interfaces in the functioning of GALA, the effect of surfaces on the reversible folding of GALA has not yet been studied. Here, we use sum frequency generation vibrational spectroscopy (SFG) to probe the structural response of GALA at the air-water interface and IR spectroscopy to follow GALA folding in bulk solution. We combine the SFG data with molecular dynamics simulations to obtain a molecular-level picture of the interaction of GALA with the air-water interface. Surprisingly, while the fully reversible structural transition was observed in solution, at the water-air interface, a large fraction of the GALA population remained helical at high pH. This "stickiness" of the air-water interface can be explained by the stabilizing interactions of hydrophobic leucine and alanine side chains with the water surface.

  9. Variation of carrier concentration and interface trap density in 8MeV electron irradiated c-Si solar cells

    International Nuclear Information System (INIS)

    The capacitance and conductance measurements were carried out for c-Si solar cells, irradiated with 8 MeV electrons with doses ranging from 5kGy – 100kGy in order to investigate the anomalous degradation of the cells in the radiation harsh environments. Capacitance – Voltage measurements indicate that there is a slight reduction in the carrier concentration upon electron irradiation due to the creation of radiation induced defects. The conductance measurement results reveal that the interface state densities and the trap time constant increases with electron dose due to displacement damages in c-Si solar cells

  10. Contact resistance of ceramic interfaces between materials used for solid oxide fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Koch, S.

    2002-01-01

    The contact resistance can be divided into two main contributions. The small area of contact between ceramic components results in resistance due to current constriction. Resistive phases or potential barriers at the interface result in an interface contribution to the contact resistance, which may be smaller or larger than the constriction resistance. The contact resistance between pairs of three different materials were analysed (strontium doped lanthanum manganite, yttria stabilised zirconia and strontium and nickel doped lanthanum cobaltite), and the effects of temperature, atmosphere, polarisation and mechanical load on the contact resistance were investigated. The investigations revealed that the mechanical load of a ceramic contact has a high influence on the contact resistance, and generally power law dependence between the contact resistance and the mechanical load was found. The influence of the mechanical load on the contact resistance was ascribed to an area effect. The contact resistance of the investigated materials was dominated by current constriction at high temperatures. The measured contact resistance was comparable to the resistance calculated on basis of the contact areas found by optical and electron microscopy. At low temperatures, the interface contribution to the contact resistance was dominating. The cobaltite interface could be described by one potential barrier at the contact interface, whereas the manganite interfaces required several consecutive potential barriers to model the observed behaviour. The current-voltage behaviour of the YSZ contact interfaces was only weakly non-linear, and could be described by 22{+-}1 barriers in series. Contact interfaces with sinterable contact layers were also investigated, and the measured contact resistance for these interfaces were more than 10 times less than for the other interfaces. (au)

  11. Designing a binding interface for control of cancer cell adhesion via 3D topography and metabolic oligosaccharide engineering.

    Science.gov (United States)

    Du, Jian; Che, Pao-Lin; Wang, Zhi-Yun; Aich, Udayanath; Yarema, Kevin J

    2011-08-01

    This study combines metabolic oligosaccharide engineering (MOE), a technology where the glycocalyx of living cells is endowed with chemical features not normally found in sugars, with custom-designed three-dimensional biomaterial substrates to enhance the adhesion of cancer cells and control their morphology and gene expression. Specifically, Ac(5)ManNTGc, a thiol-bearing analog of N-acetyl-d-mannosamine (ManNAc) was used to introduce thiolated sialic acids into the glycocalyx of human Jurkat T-lymphoma derived cells. In parallel 2D films and 3D electrospun nanofibrous scaffolds were prepared from polyethersulfone (PES) and (as controls) left unmodified or aminated. Alternately, the materials were malemided or gold-coated to provide bio-orthogonal binding partners for the thiol groups newly expressed on the cell surface. Cell attachment was modulated by both the topography of the substrate surface and by the chemical compatibility of the binding interface between the cell and the substrate; a substantial increase in binding for normally non-adhesive Jurkat line for 3D scaffold compared to 2D surfaces with an added degree of adhesion resulting from chemoselective binding to malemidede-derivatived or gold-coated surfaces. In addition, the morphology of the cells attached to the 3D scaffolds via MOE-mediated adhesion was dramatically altered and the expression of genes involved in cell adhesion changed in a time-dependent manner. This study showed that cell adhesion could be enhanced, gene expression modulated, and cell fate controlled by introducing the 3D topograhical cues into the growth substrate and by creating a glycoengineered binding interface where the chemistry of both the cell surface and biomaterials scaffold was controlled to facilitate a new mode of carbohydrate-mediated adhesion. PMID:21549424

  12. Constructing skin-equivalents using hair follicle stem cells

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective: To establish the method of constructing skin-equivalents (SE) using hair follicle stem cells(HFSC).Methods: K19 positive cells derived from hair were cultivated using serum-free medium KGM and seeded on dermal equivalents (DE).After the culture between the air-liquid interface for 14 days, SE were harvested and used for evaluation. Results: K19 positive cells chosen as HFSC were located in bulge of out root sheet in hair follicle. Cultivated HFSC could build a fully developed, multi-layered epidermis on the basis of DE, resembling the skin structure. Conclusion: HFSC located in out root sheet can differentiate into keratinocyte in vitro and be used for SE construction.

  13. Nanoscale Interfaces in Colloidal Quantum Dot Solar Cells: Physical Insights and Materials Engineering Strategies

    Science.gov (United States)

    Kemp, Kyle Wayne

    With growing global energy demand there will be an increased need for sources of renewable energy such as solar cells. To make these photovoltaic technologies more competitive with conventional energy sources such as coal and natural gas requires further reduction in manufacturing costs that can be realized by solution processing and roll-to-roll printing. Colloidal quantum dots are a bandgap tunable, solution processible, semiconductor material which may offer a path forward to efficient, inexpensive photovoltaics. Despite impressive progress in performance with these materials, there remain limitations in photocarrier collection that must be overcome. This dissertation focuses on the characterization of charge recombination and transport in colloidal quantum dot photovoltaics, and the application of this knowledge to the development of new and better materials. Core-shell, PbS-CdS, quantum dots were investigated in an attempt to achieve better surface passivation and reduce electronic defects which can limit performance. Optimization of this material led to improved open circuit voltage, exceeding 0.6 V for the first time, and record published performance of 6% efficiency. Using temperature-dependent and transient photovoltage measurements we explored the significance of interface recombination on the operation of these devices. Careful engineering of the electrode using atomic layer deposition of ZnO helped lead to better TiO2 substrate materials and allowed us to realize a nearly two-fold reduction in recombination rate and an enhancement upwards of 50 mV in open circuit voltage. Carrier extraction efficiency was studied in these devices using intensity dependent current-voltage data of an operational solar cell. By developing an analytical model to describe recombination loss within the active layer of the device we were able to accurately determine transport lengths ranging up to 90 nm. Transient absorption and photoconductivity techniques were used to study

  14. ZnO/aSi interface charge carriers transport in Li-ion secondary cell anodes

    International Nuclear Information System (INIS)

    Electron and Li-ion transport at the n-ZnO/p-aSi (amorphous Si) heterojunction interface is analyzed for the initial charging conditions of a secondary battery anode. The ohmic and diode-type current–voltage characteristics of the junction are investigated for varying doping levels of aSi and ZnO layers. The interface potential barrier impacts the electrons supply to control the Li + ZnO → Li2O + LixZn reaction. The interface electric field could exceed ∼105 V cm−1 and draws in Li ions from zinc oxide into the silicon layer. Relatively low-level doping (∼1018 cm−3) of the semiconductors is preferred for the optimum draw-in effect. During the initial charging, when the Li content in ZnO (as substitution LiZn acceptors) does not exceed the solubility level (∼1019 cm−3), the overall doping maintains the n-type, and the interface electric field continues to draw in Li ions towards silicon. Under further increase of Li content at interstitials, the layer conductivity is converted, and the heterojunction becomes n−–n–p (or even p–n–p) type. During the subsequent transport of Li ions, the interface potential barrier diminishes and vanishes, and the current–voltage characteristics become ohmic. The importance of doping level control for both the materials is emphasized. The results are applicable for interface engineering in LIB anodes. - Highlights: • n-ZnO/p-aSi interface potential barrier controls electrons supply for Li coupling reaction. • The interface electric field exceeds 105 V cm−1 to draws in Li ions from ZnO into aSi. • n-ZnO/p-aSi heterojunction could have ohmic or diode type behavior under initial charging

  15. Design of Pt-CeOx hetero-interface on electrodes in polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Pt-CeOx interface on Pt electrodes was prepared for improvement of both oxygen reduction reaction (ORR) activity of Pt cathode and CO tolerance of Pt anode. The surface of Pt-CeOx nano-particle/C electrode mainly consists of metallic Pt, ionized Pt (i.e. Pt2+) and Ce3+ species. The ORR activity on Pt was improved by the formation of Pt-CeOx interface. In-situ XAFS analysis suggests that cerium oxide surface in the Pt-CeOx/C was oxidized instead of Pt surface by electrochemical redox reaction of CeOx at room temperature. This suggests that the Pt-CeOx interface plays key role for improvement of cathode performance. Also, CO tolerance of Pt was improved by the formation of aforementioned interface. The improvement of CO tolerance of Pt was also observed by using in-situ IR analysis. Based on all experimental data, it is concluded that the design of defect structure in Pt-CeOx provides us opportunity to make the breakthrough electrodes for fuel cell application

  16. Roles of Energy/Charge Cascades and Intermixed Layers at Donor/Acceptor Interfaces in Organic Solar Cells

    Science.gov (United States)

    Nakano, Kyohei; Suzuki, Kaori; Chen, Yujiao; Tajima, Keisuke

    2016-01-01

    The secret to the success of mixed bulk heterojunctions (BHJs) in yielding highly efficient organic solar cells (OSCs) could reside in the molecular structures at their donor/acceptor (D/A) interfaces. In this study, we aimed to determine the effects of energy and charge cascade structures at the interfaces by using well-defined planar heterojunctions (PHJs) as a model system. The results showed that (1) the charge cascade structure enhanced VOC because it shuts down the recombination pathway through charge transfer (CT) state with a low energy, (2) the charge cascade layer having a wider energy gap than the bulk material decreased JSC because the diffusion of the excitons from the bulk to D/A interface was blocked; the energy of the cascade layers must be appropriately arranged for both the charges and the excitons, and (3) molecular intermixing in the cascade layer opened the recombination path through the low-energy CT state and decreased VOC. Based on these findings, we propose improved structures for D/A interfaces in BHJs. PMID:27404948

  17. Transport and metabolism at blood-brain interfaces and in neural cells: relevance to bilirubin-induced encephalopathy

    Directory of Open Access Journals (Sweden)

    Silvia eGazzin

    2012-05-01

    Full Text Available Bilirubin, the end-product of heme catabolism, circulates in non pathological plasma mostly as a protein-bound species. When bilirubin concentration builds up, the free fraction of the molecule increases. Unbound bilirubin then diffuses across blood-brain interfaces into the brain, where it accumulates and exerts neurotoxic effects. In this classical view of bilirubin neurotoxicity, blood-brain interfaces act merely as structural barriers impeding the penetration of the pigment-bound carrier protein, and neural cells are considered as passive targets of its toxicity. Yet, the role of blood-brain interfaces in the occurrence of bilirubin encephalopathy appears more complex than being simple barriers to the diffusion of bilirubin, and neural cells such as astrocytes and neurons can play an active role in controlling the balance between the neuroprotective and neurotoxic effects of bilirubin. This article reviews the emerging in vivo and in vitro data showing that transport and metabolic detoxification mechanisms at the blood-brain and blood-CSF barriers may modulate bilirubin flux across both cellular interfaces, and that these protective functions can be affected in chronic hyperbilirubinemia. Then the in vivo and in vitro arguments in favor of the physiological antioxidant function of intracerebral bilirubin are presented, as well as with the potential role of transporters such as ABCC-1 and metabolizing enzymes such as cytochromes P-450 in setting the cerebral cell- and structure-specific toxicity of bilirubin following hyperbilirubinemia. The relevance of these data to the pathophysiology of bilirubin-induced neurological diseases is discussed.

  18. Progress in the integration of Test Blanket Systems in ITER equatorial port cells and in the interfaces definition

    International Nuclear Information System (INIS)

    Highlights: ► The design integration of two test blanket systems in ITER port cell is addressed. ► Definition of interfaces of TBSs with building and other ITER systems is done. ► Designs of pipe forest, bioshield plug and ancillary equipment unit are described. ► The maintenance of the two test blanket systems in ITER port cell is considered. ► The management of the heat and tritium releases in the TBM port cell is described. - Abstract: In the framework of the TBM Program, three ITER vacuum vessel equatorial ports (no. 16, no. 18 and no. 02) have been allocated for the testing of up to six mock-ups of six different DEMO tritium breeding blankets. Each one is called a Test Blanket System (TBS). A TBS consists mainly of the Test Blanket Module (TBM), the in-vessel component facing the plasma, and several ancillary systems, in particular the cooling system and the tritium extraction system. Each port accommodates two TBMs and therefore the two TBSs have to share the corresponding port cell. This paper deals with the design integration aspects of the two TBSs in each port cell performed at ITER Organization (IO) with the corresponding definition of interfaces with other ITER systems. The performed activities have raised several issues that are discussed in the paper and for which design solutions are proposed.

  19. A LytM Domain Dictates the Localization of Proteins to the Mother Cell-Forespore Interface during Bacterial Endospore Formation▿ †

    OpenAIRE

    Meisner, Jeffrey; Moran, Charles P.

    2010-01-01

    A large number of proteins are known to reside at specific subcellular locations in bacterial cells. However, the molecular mechanisms by which many of these proteins are anchored at these locations remains unclear. During endospore formation in Bacillus subtilis, several integral membrane proteins are located specifically at the interface of the two adjacent cells of the developing sporangium, the mother cell and forespore. The mother cell membrane protein SpoIIIAH recognizes the cell-cell i...

  20. Dynamics of Metal Partitioning at the Cell-Solution Interface: Implications for Toxicity Assessment under Growth-Inhibiting Conditions.

    Science.gov (United States)

    Duval, Jérôme F L; Paquet, Nathalie; Lavoie, Michel; Fortin, Claude

    2015-06-01

    Metal toxicity toward microorganisms is usually evaluated by determining growth inhibition. To achieve a mechanistic interpretation of such toxic effects, the intricate coupling between cell growth kinetics and metal partitioning dynamics at the cell-solution interface over time must be considered on a quantitative level. A formalism is elaborated to evaluate cell-surface-bound, internalized, and extracellular metal fractions in the limit where metal uptake kinetics is controlled by internalization under noncomplexing medium conditions. Cell growth kinetics is tackled using the continuous logistic equation modified to include growth inhibition by metal accumulation to intracellular or cell surface sites. The theory further includes metal-proton competition for adsorption at cell-surface binding sites, as well as possible variation of cell size during exposure to metal ions. The formalism elucidates the dramatic impacts of initial cell concentration on metal bioavailability and toxicity over time, in agreement with reported algae bioassays. It further highlights that appropriate definition of toxicity endpoints requires careful inspection of the ratio between exposure time scale and time scale of metal depletion from bulk solution. The latter depends on metal internalization-excretion rate constants, microorganism growth, and the extent of metal adsorption on nonspecific, transporter, and growth inhibitory sites. As an application of the theory, Cd toxicity in the algae Pseudokirchneriella subcapitata is interpreted from constrained modeling of cell growth kinetics and of interfacial Cd-partitioning dynamics measured under various exposure conditions. PMID:25945520

  1. Study of interface layer effect in organic solar cells by electric-field-induced optical second-harmonic generation measurement

    International Nuclear Information System (INIS)

    By using electric-field-induced optical second-harmonic generation (EFISHG) measurement, we studied the effect of the use of bathocuproine (BCP) interface layer. The EFISHG measurements of indium–zinc–oxide (IZO)/C60/Al diodes showed that the BCP layer inserted between C60 and Al formed an electrostatic field |Ei| = 2.5 × 104 V/cm in the C60 layer, pointing in a direction from the Al to the IZO. Accordingly, in the IZO/pentacene/C60/BCP/Al organic solar cells (OSCs), holes (electrons) move to the IZO (Al) electrode, enhancing the short-circuit current. The EFISHG measurement is capable of directly probing internal fields in the layers used for OSCs, and is helpful for studying the contribution of the interface layer in OSCs. - Highlights: • Internal field in organic solar cells (OSCs) were directly probed. • Interface layer formed internal electric field, enhancing the OSC performance. • Maxwell–Wagner effect accounts for the internal electric field formation

  2. Study of interface layer effect in organic solar cells by electric-field-induced optical second-harmonic generation measurement

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, Dai; Sumiyoshi, Ryota; Chen, Xiangyu; Manaka, Takaaki; Iwamoto, Mitsumasa, E-mail: iwamoto@pe.titech.ac.jp

    2014-03-03

    By using electric-field-induced optical second-harmonic generation (EFISHG) measurement, we studied the effect of the use of bathocuproine (BCP) interface layer. The EFISHG measurements of indium–zinc–oxide (IZO)/C{sub 60}/Al diodes showed that the BCP layer inserted between C{sub 60} and Al formed an electrostatic field |E{sub i}| = 2.5 × 10{sup 4} V/cm in the C{sub 60} layer, pointing in a direction from the Al to the IZO. Accordingly, in the IZO/pentacene/C{sub 60}/BCP/Al organic solar cells (OSCs), holes (electrons) move to the IZO (Al) electrode, enhancing the short-circuit current. The EFISHG measurement is capable of directly probing internal fields in the layers used for OSCs, and is helpful for studying the contribution of the interface layer in OSCs. - Highlights: • Internal field in organic solar cells (OSCs) were directly probed. • Interface layer formed internal electric field, enhancing the OSC performance. • Maxwell–Wagner effect accounts for the internal electric field formation.

  3. Investigations of Pulmonary Epithelial Cell Damage due to Air-Liquid Interfacial Stresses in a Microgravity Environment

    Science.gov (United States)

    Gaver, Donald P., III; Bilek, A. M.; Kay, S.; Dee, K. C.

    2004-01-01

    Pulmonary airway closure is a potentially dangerous event that can occur in microgravity environments and may result in limited gas exchange for flight crew during long-term space flight. Repetitive airway collapse and reopening subjects the pulmonary epithelium to large, dynamic, and potentially injurious mechanical stresses. During ventilation at low lung volumes and pressures, airway instability leads to repetitive collapse and reopening. During reopening, air must progress through a collapsed airway, generating stresses on the airway walls, potentially damaging airway tissues. The normal lung can tolerate repetitive collapse and reopening. However, combined with insufficient or dysfunctional pulmonary surfactant, repetitive airway collapse and reopening produces severe lung injury. Particularly at risk is the pulmonary epithelium. As an important regulator of lung function and physiology, the degree of pulmonary epithelial damage influences the course and outcome of lung injury. In this paper we present experimental and computational studies to explore the hypothesis that the mechanical stresses associated with airway reopening inflict injury to the pulmonary epithelium.

  4. Single-cell RNA-seq reveals cell type-specific transcriptional signatures at the maternal–foetal interface during pregnancy

    Science.gov (United States)

    Nelson, Andrew C.; Mould, Arne W.; Bikoff, Elizabeth K.; Robertson, Elizabeth J.

    2016-01-01

    Growth and survival of the mammalian embryo within the uterine environment depends on the placenta, a highly complex vascularized organ comprised of both maternal and foetal tissues. Recent experiments demonstrate that the zinc finger transcriptional repressor Prdm1/Blimp1 is essential for specification of spiral artery trophoblast giant cells (SpA-TGCs) that invade and remodel maternal blood vessels. To learn more about functional contributions made by Blimp1+ cell lineages here we perform the first single-cell RNA-seq analysis of the placenta. Cell types of both foetal and maternal origin are profiled. Comparisons with microarray datasets from mutant placenta and in vitro differentiated trophoblast stem cells allow us to identify Blimp1-dependent transcripts enriched in SpA-TGCs. Our experiments provide new insights into the functionally distinct cell types present at the maternal–foetal interface and advance our knowledge of dynamic gene expression patterns controlling placental morphogenesis and vascular mimicry. PMID:27108815

  5. Hot-cell design considerations for interfacing eddy-current systems

    International Nuclear Information System (INIS)

    The Hot Fuel Examination Facility/North conducts remote eddy-current examination of irradiated fuel elements. Applications include cladding breach detection and irradiation-induced ferrite examination. The seccussful use of remote eddy-current techniques is achieved by applying basic test parameters and interfacing considerations. These include impedance matching, operating frequency, and feedthrough considerations

  6. Characterisation of the Ni/ScYSZ interface in a model solid oxide fuel cell anode

    DEFF Research Database (Denmark)

    Schmidt, Michael Stenbæk; Hansen, Karin Vels; Norrman, Kion;

    2008-01-01

    impedance spectroscopy data with time-of-flight secondary ion mass spectrometry, scanning electron microscopy and atomic force microscopy data. A semi-quantitative analysis of the electrolyte surfaces showed that the levels of surface impurities inside the electrode/electrolyte interface in close proximity...

  7. Evolution of the electrochemical interface in high-temperature fuel cells and electrolysers

    DEFF Research Database (Denmark)

    Irvine, John T.S.; Neagu, Dragos; Verbraeken, Maarten C.;

    2016-01-01

    The critical region determining the performance and lifetime of solid oxide electrochemical systems is normally at the electrode side of the electrode/electrolyte interface. Typically this electrochemically active region only extends a few micrometres and for best performance involves intricate s...

  8. EDITORIAL: Nanotechnology at the interface of cell biology, materials science and medicine Nanotechnology at the interface of cell biology, materials science and medicine

    Science.gov (United States)

    Engel, Andreas; Miles, Mervyn

    2008-09-01

    The atomic force microscope (AFM) and related scanning probe microscopes have become resourceful tools to study cells, supramolecular assemblies and single biomolecules, because they allow investigations of such structures in native environments. Quantitative information has been gathered about the surface structure of membrane proteins to lateral and vertical resolutions of 0.5 nm and 0.1 nm, respectively, about the forces that keep protein-protein and protein-nucleic acid assemblies together as well as single proteins in their native conformation, and about the nanomechanical properties of cells in health and disease. Such progress has been achieved mainly because of constant development of AFM instrumentation and sample preparation methods. This special issue of Nanotechnology presents papers from leading laboratories in the field of nanobiology, covering a wide range of topics in the form of original and novel scientific contributions. It addresses achievements in instrumentation, sample preparation, automation and in biological applications. These papers document the creativity and persistence of researchers pursuing the goal to unravel the structure and dynamics of cells, supramolecuar structures and single biomolecules at work. Improved cantilever sensors, novel optical probes, and quantitative data on supports for electrochemical experiments open new avenues for characterizing biological nanomachines down to the single molecule. Comparative measurements of healthy and metastatic cells promise new methods for early detection of tumors, and possible assessments of drug efficacy. High-speed AFMs document possibilities to monitor crystal growth and to observe large structures at video rate. A wealth of information on amyloid-type fibers as well as on membrane proteins has been gathered by single molecule force spectroscopy—a technology now being automated for large-scale data collection. With the progress of basic research and a strong industry supporting

  9. Promotion of water-mediated carbon removal by nanostructured barium oxide/nickel interfaces in solid oxide fuel cells

    OpenAIRE

    Yang, Lei; Choi, YongMan; Qin, Wentao; Chen, Haiyan; Blinn, Kevin; Liu, Mingfei; Liu, Ping; Bai, Jianming; Trevor A. Tyson; Liu, Meilin

    2011-01-01

    The existing Ni-yttria-stabilized zirconia anodes in solid oxide fuel cells (SOFCs) perform poorly in carbon-containing fuels because of coking and deactivation at desired operating temperatures. Here we report a new anode with nanostructured barium oxide/nickel (BaO/Ni) interfaces for low-cost SOFCs, demonstrating high power density and stability in C3H8, CO and gasified carbon fuels at 750°C. Synchrotron-based X-ray analyses and microscopy reveal that nanosized BaO islands grow on the Ni su...

  10. Storable droplet interface lipid bilayers for cell-free ion channel studies.

    Science.gov (United States)

    Jung, Sung-Ho; Choi, Sangbaek; Kim, Young-Rok; Jeon, Tae-Joon

    2012-01-01

    An artificially created lipid bilayer is an important platform in studying ion channels and engineered biosensor applications. However, a lipid bilayer created using conventional techniques is fragile and short-lived, and the measurement of ion channels requires expertise and laborious procedures, precluding practical applications. Here, we demonstrate a storable droplet lipid bilayer precursor frozen with ion channels, resulting in a droplet interface bilayer upon thawing. A small vial with an aqueous droplet in organic solution was flash frozen in -80 °C methanol immediately after an aqueous droplet was introduced into the organic solution and gravity draws the droplet down to the interface upon thawing. A lipid bilayer created along the interface using this method had giga-ohm resistance and typical specific capacitance values. The noise level of this system is favorably comparable to the conventional system. The subsequent incorporation of ion channels, alpha-hemolysin and gramicidin A, showed typical conductance values consistent with those in previous literatures. This novel system to create a lipid bilayer as a whole can be automated from its manufacture to use and indefinitely stored when frozen. As a result, ion channel measurements can be carried out in any place, increasing the accessibility of ion channel studies as well as a number of applications, such as biosensors, ion channel drug screening, and biophysical studies. PMID:21909672

  11. Bluetooth wireless monitoring, diagnosis and calibration interface for control system of fuel cell bus in Olympic demonstration

    Science.gov (United States)

    Hua, Jianfeng; Lin, Xinfan; Xu, Liangfei; Li, Jianqiu; Ouyang, Minggao

    With the worldwide deterioration of the natural environment and the fossil fuel crisis, the possible commercialization of fuel cell vehicles has become a hot topic. In July 2008, Beijing started a clean public transportation plan for the 29th Olympic games. Three fuel cell city buses and 497 other low-emission vehicles are now serving the Olympic core area and Beijing urban areas. The fuel cell buses will operate along a fixed bus line for 1 year as a public demonstration of green energy vehicles. Due to the specialized nature of fuel cell engines and electrified power-train systems, measurement, monitoring and calibration devices are indispensable. Based on the latest Bluetooth wireless technology, a novel Bluetooth universal data interface was developed for the control system of the fuel cell city bus. On this platform, a series of wireless portable control auxiliary systems have been implemented, including wireless calibration, a monitoring system and an in-system programming platform, all of which are ensuring normal operation of the fuel cell buses used in the demonstration.

  12. Bluetooth wireless monitoring, diagnosis and calibration interface for control system of fuel cell bus in Olympic demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Hua, Jianfeng; Lin, Xinfan; Xu, Liangfei; Li, Jianqiu; Ouyang, Minggao [Tsinghua University, State Key Laboratory of Automotive Safety and Energy, Beijing100084 (China)

    2009-01-15

    With the worldwide deterioration of the natural environment and the fossil fuel crisis, the possible commercialization of fuel cell vehicles has become a hot topic. In July 2008, Beijing started a clean public transportation plan for the 29th Olympic games. Three fuel cell city buses and 497 other low-emission vehicles are now serving the Olympic core area and Beijing urban areas. The fuel cell buses will operate along a fixed bus line for 1 year as a public demonstration of green energy vehicles. Due to the specialized nature of fuel cell engines and electrified power-train systems, measurement, monitoring and calibration devices are indispensable. Based on the latest Bluetooth wireless technology, a novel Bluetooth universal data interface was developed for the control system of the fuel cell city bus. On this platform, a series of wireless portable control auxiliary systems have been implemented, including wireless calibration, a monitoring system and an in-system programming platform, all of which are ensuring normal operation of the fuel cell buses used in the demonstration. (author)

  13. IL-10 and TGF-β Control of Dendritic Cells at Environmental Interfaces

    OpenAIRE

    Girard-Madoux, Mathilde

    2014-01-01

    markdownabstract__Abstract__ Dendritic cells (DC) are necessary to maintain homeostasis and are essential in regulating immune responses. DC induce effector T cell responses to invading pathogens and promote regulatory T cell (Treg) differentiation to harmless antigens. Interleukin-10 (IL-10) and transforming growth factor β (TGF-β) are anti-inflammatory cytokines displaying potent tolerogenic abilities. Both cytokines are secreted by and act on a plethora of (non-) immune cells including T c...

  14. IL-10 and TGF-β Control of Dendritic Cells at Environmental Interfaces

    NARCIS (Netherlands)

    M.J.H. Girard-Madoux (Mathilde)

    2014-01-01

    markdownabstract__Abstract__ Dendritic cells (DC) are necessary to maintain homeostasis and are essential in regulating immune responses. DC induce effector T cell responses to invading pathogens and promote regulatory T cell (Treg) differentiation to harmless antigens. Interleukin-10 (IL-10) and t

  15. Interface oxygen and heat sensitivity of Cu(In,Ga)Se2 and CuGaSe2 solar cells

    Science.gov (United States)

    Ishizuka, Shogo; Fons, Paul J.; Yamada, Akimasa; Kamikawa-Shimizu, Yukiko; Shibata, Hajime

    2016-05-01

    Combined oxygen and heat exposure processes after p-CuGaSe2/n-CdS junction formation degrade CuGaSe2 solar cell efficiency, whereas such annealing processes can improve high In content Cu(In,Ga)Se2 device performance. This result is chiefly attributable to different interface structures consisting of oxygen-sensitive CuGaSe2 or relatively oxygen-insensitive Cu(In,Ga)Se2. To reduce CuGaSe2 interfacial recombination, reduction of the process temperature of the front contact layer deposition process is found to be the key. In this work, fill factor values exceeding 0.7 are reproducibly obtained from CuGaSe2 solar cells, though such high fill factor values have been very challenging to demonstrate to date using CuGaSe2 photoabsorber layers.

  16. Surface and Interface Properties of 10–12 Unit Cells Thick Sputter Deposited Epitaxial CeO2 Films

    Directory of Open Access Journals (Sweden)

    L. V. Saraf

    2008-01-01

    Full Text Available Ultrathin and continuous epitaxial films with relaxed lattice strain can potentially maintain more of its bulk physical and chemical properties and are useful as buffer layers. We study surface, interface, and microstructural properties of ultrathin (∼10–12 unit cells thick epitaxial ceria films grown on single crystal YSZ substrates. The out-of -plane and in-plane lattice parameters indicate relaxation in the continuous film due to misfit dislocations seen by high-resolution transmission electron microscopy (HRTEM and substrate roughness of ∼1-2 unit cells, confirmed by atomic force microscopy and HRTEM. A combination of secondary sputtering, lattice mismatch, substrate roughness, and surface reduction creating secondary phase was likely the cause of surface roughness which should be reduced to a minimum level for effective use of it as buffer layers.

  17. A novel nano-sized bionic function interface for enhancing the ability of red blood cells to carry oxygen

    International Nuclear Information System (INIS)

    A nano-sized bionic function interface was prepared by immobilizing red blood cells onto a silver electrode, which was modified with cysteamine and colloidal gold. Scanning electron microscopy and electrochemical impedance spectroscopy were used to characterize its surface. Cyclic voltammograms in phosphate buffer solution of pH 7.0 exhibited a pair of redox peaks for oxygen at -378 and -207 mV, respectively. The reduction peak currents at -378 mV were linearly proportional to the oxygen concentration in the range from 12.6 μM to 1.39 mM. Cyclic voltammetry also indicated that the functional surface enhanced the ability of red blood cells to transport oxygen. (author)

  18. Special Morphological Features at the Interface of the Renal Stem/Progenitor Cell Niche Force to Reinvestigate Transport of Morphogens During Nephron Induction

    OpenAIRE

    Minuth, Will W.; Denk, Lucia

    2016-01-01

    Abstract Formation of a nephron depends on reciprocal signaling of different morphogens between epithelial and mesenchymal cells within the renal stem/progenitor cell niche. Previously, it has been surmised that a close proximity exists between both involved cell types and that morphogens are transported between them by diffusion. However, actual morphological data illustrate that mesenchymal and epithelial stem/progenitor cell bodies are separated by a striking interface. Special fixation of...

  19. Ciprofloxacin Is Actively Transported across Bronchial Lung Epithelial Cells Using a Calu-3 Air Interface Cell Model

    OpenAIRE

    Ong, Hui Xin; Traini, Daniela; Bebawy, Mary; Young, Paul M.

    2013-01-01

    Ciprofloxacin is a well-established broad-spectrum fluoroquinolone antibiotic that penetrates well into the lung tissues; still, the mechanisms of its transepithelial transport are unknown. The contributions of specific transporters, including multidrug efflux transporters, organic cation transporters, and organic anion-transporting polypeptide transporters, to the uptake of ciprofloxacin were investigated in vitro using an air interface bronchial epithelial model. Our results demonstrate tha...

  20. Differential expression of the metastasis suppressor KAI1 in decidual cells and trophoblast giant cells at the feto-maternal interface

    Directory of Open Access Journals (Sweden)

    Tae Bon Koo

    2013-10-01

    Full Text Available Invasion of trophoblasts into maternal uterine tissue is essentialfor establishing mature feto-maternal circulation. The trophoblastinvasion associated with placentation is similar to tumorinvasion. In this study, we investigated the role of KAI1, ananti-metastasis factor, at the maternal-fetal interface duringplacentation. Mouse embryos were obtained from gestationaldays 5.5 (E5.5 to E13.5. Immunohistochemical analysis revealedthat KAI1 was expressed on decidual cells around the trackmade when a fertilized ovum invaded the endometrium, at daysE5.5 and E7.5, and on trophoblast giant cells, along the centralmaternal artery of the placenta at E9.5. KAI1 in trophoblast giantcells was increased at E11.5, and then decreased at E13.5.Furthermore, KAI1 was upregulated during the forskolinmediatedtrophoblastic differentiation of BeWo cells. Collectively,these results indicate that KAI1 is differentially expressedin decidual cells and trophoblasts at the maternal-fetal interface,suggesting that KAI1 prevents trophoblast invasion duringplacentation. [BMB Reports 2013; 46(10: 507-512

  1. Investigation of the origin of stromal and endothelial cells at the desmoplastic interface in xenograft tumor in mice.

    Science.gov (United States)

    Jung, Minsun; Ryu, Young-joon; Kang, Gu

    2015-12-01

    Carcinoma-associated fibroblasts found at the interface between a tumor and the normal stroma play several roles in the development of cancer, including cancer initiation, growth, and progression, thereby also affecting patient prognosis. Although recent studies have focused on carcinoma-associated fibroblasts as potential treatment targets, the origin of these fibroblasts remains unclear. One theory suggests that these cells arise from tumor cells undergoing the epithelial-mesenchymal transition, i.e., tumor cells transform into carcinoma-associated fibroblasts. Therefore, in this study, we aimed to elucidate the cellular origin of carcinoma-associated fibroblasts in a mouse xenograft model. Mice were transplanted with human lung cancer cells (H226 and A549 cells). After sacrifice, tumor masses and surrounding tissues were excised. Interestingly, the excised xenograft tissues contained a significant proportion of desmoplastic fibroblasts that exhibited strong expression of α-smooth muscle actin (SMA). Immunohistochemical staining with pan-cytokeratin, vimentin, β-catenin, E-cadherin, and CD34 showed no evidence of the epithelial-mesenchymal transition. Additional evaluation using dual-color silver in situ hybridization with dinitrophenyl-labeled human epidermal growth factor receptor 2 (HER2) and digoxigenin-labeled chromosome 17 centromere probes also showed similar results. In conclusion, our results revealed that the epithelial-mesenchymal transition may not occur in tumor xenograft models, regardless of evidence supporting this phenomenon in humans. PMID:26564105

  2. Relation between photovoltaic characteristics and acceptor concentration at the interface of indium oxide/indium phosphide heterojunction solar cell

    International Nuclear Information System (INIS)

    Photovoltaic characteristics of a heterojunction solar cell composed of reactively evaporated indium oxide (In2O3) film and single crystalline p-type indium phosphide (InP) was found to depend on acceptor concentration at the interface. The value of acceptor concentration was preferable to be high to obtain a high performance cell because larger open-circuit voltage can be obtained due to decrease of diode saturation current of the cell with the increase of the acceptor concentration. The acceptor concentration of the cell was increased by annealing during forming an ohmic contact. The increase of acceptor concentration by annealing thought to be able to explain in terms of out diffusion of the interstitial zinc atoms in InP bulk. Further, the value of acceptor concentration is modified by substrate heating during deposition of transparent and conductive In2O3 film. In order to produce a high performance cell, low substrate temperature (200 deg C) was preferable during deposition of In2O3 (Authors)

  3. Indications for presence and importance of interface states in CdTe/CdS solar cells

    International Nuclear Information System (INIS)

    Quantum efficiency measurements under forward voltage bias conditions often show a large response in the wavelength region from 350 to 500 nm. It is seen that the light induced changes do not only cause a higher current in the illuminated case than in the dark case at forward bias (the situation which is explained in earlier work), but also often on the contrary a lower current at moderate forward bias (the current direction can be deduced from the phase shift between input signal and response signal). This second situation can be studied in detail by comparing the I-V curves in dark to the ones illuminated with the monochromatic light under consideration. Also the dependence of the response on the illumination intensity can be clearly shown in these measurements. A model for this situation is built up, making use of traps at the CdTe/CdS interface and extending a previously presented model. This model shows that the quantum efficiency measurement is a sensitive method to determine the presence of interface states

  4. A Nanoscale Interface Promoting Molecular and Functional Differentiation of Neural Cells.

    Science.gov (United States)

    Posati, Tamara; Pistone, Assunta; Saracino, Emanuela; Formaggio, Francesco; Mola, Maria Grazia; Troni, Elisabetta; Sagnella, Anna; Nocchetti, Morena; Barbalinardo, Marianna; Valle, Francesco; Bonetti, Simone; Caprini, Marco; Nicchia, Grazia Paola; Zamboni, Roberto; Muccini, Michele; Benfenati, Valentina

    2016-01-01

    Potassium channels and aquaporins expressed by astrocytes are key players in the maintenance of cerebral homeostasis and in brain pathophysiologies. One major challenge in the study of astrocyte membrane channels in vitro, is that their expression pattern does not resemble the one observed in vivo. Nanostructured interfaces represent a significant resource to control the cellular behaviour and functionalities at micro and nanoscale as well as to generate novel and more reliable models to study astrocytes in vitro. However, the potential of nanotechnologies in the manipulation of astrocytes ion channels and aquaporins has never been previously reported. Hydrotalcite-like compounds (HTlc) are layered materials with increasing potential as biocompatible nanoscale interface. Here, we evaluate the effect of the interaction of HTlc nanoparticles films with primary rat neocortical astrocytes. We show that HTlc films are biocompatible and do not promote gliotic reaction, while favouring astrocytes differentiation by induction of F-actin fibre alignment and vinculin polarization. Western Blot, Immunofluorescence and patch-clamp revealed that differentiation was accompanied by molecular and functional up-regulation of both inward rectifying potassium channel Kir 4.1 and aquaporin 4, AQP4. The reported results pave the way to engineering novel in vitro models to study astrocytes in a in vivo like condition. PMID:27503424

  5. Optically tunable spin-exchange energy at donor:acceptor interfaces in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mingxing; Wang, Hongfeng; He, Lei; Zang, Huidong; Xu, Hengxing; Hu, Bin, E-mail: bhu@utk.edu [Department of Materials Science and Engineering, University of Tennessee Knoxville, Tennessee 37996 (United States)

    2014-07-14

    Spin-exchange energy is a critical parameter in controlling spin-dependent optic, electronic, and magnetic properties in organic materials. This article reports optically tunable spin-exchange energy by studying the line-shape characteristics in magnetic field effect of photocurrent developed from intermolecular charge-transfer states based on donor:acceptor (P3HT:PCBM) system. Specifically, we divide magnetic field effect of photocurrent into hyperfine (at low field < 10 mT) and spin-exchange (at high field > 10 mT) regimes. We observe that increasing photoexcitation intensity can lead to a significant line-shape narrowing in magnetic field effect of photocurrent occurring at the spin-exchange regime. We analyze that the line-shape characteristics is essentially determined by the changing rate of magnetic field-dependent singlet/triplet ratio when a magnetic field perturbs the singlet-triplet transition through spin mixing. Based on our analysis, the line-shape narrowing results indicate that the spin-exchange energy at D:A interfaces can be optically changed by changing photoexcitation intensity through the interactions between intermolecular charge-transfer states. Therefore, our experimental results demonstrate an optical approach to change the spin-exchange energy through the interactions between intermolecular charge-transfer states at donor:acceptor interface in organic materials.

  6. Optically tunable spin-exchange energy at donor:acceptor interfaces in organic solar cells

    International Nuclear Information System (INIS)

    Spin-exchange energy is a critical parameter in controlling spin-dependent optic, electronic, and magnetic properties in organic materials. This article reports optically tunable spin-exchange energy by studying the line-shape characteristics in magnetic field effect of photocurrent developed from intermolecular charge-transfer states based on donor:acceptor (P3HT:PCBM) system. Specifically, we divide magnetic field effect of photocurrent into hyperfine (at low field  10 mT) regimes. We observe that increasing photoexcitation intensity can lead to a significant line-shape narrowing in magnetic field effect of photocurrent occurring at the spin-exchange regime. We analyze that the line-shape characteristics is essentially determined by the changing rate of magnetic field-dependent singlet/triplet ratio when a magnetic field perturbs the singlet-triplet transition through spin mixing. Based on our analysis, the line-shape narrowing results indicate that the spin-exchange energy at D:A interfaces can be optically changed by changing photoexcitation intensity through the interactions between intermolecular charge-transfer states. Therefore, our experimental results demonstrate an optical approach to change the spin-exchange energy through the interactions between intermolecular charge-transfer states at donor:acceptor interface in organic materials.

  7. Kinetic Interface

    DEFF Research Database (Denmark)

    2009-01-01

    A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises.......A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises....

  8. Phosphatidylinositol 3-phosphates-at the interface between cell signalling and membrane traffic.

    Science.gov (United States)

    Marat, Andrea L; Haucke, Volker

    2016-03-15

    Phosphoinositides (PIs) form a minor class of phospholipids with crucial functions in cell physiology, ranging from cell signalling and motility to a role as signposts of compartmental membrane identity. Phosphatidylinositol 3-phosphates are present at the plasma membrane and within the endolysosomal system, where they serve as key regulators of both cell signalling and of intracellular membrane traffic. Here, we provide an overview of the metabolic pathways that regulate cellular synthesis of PI 3-phosphates at distinct intracellular sites and discuss the mechanisms by which these lipids regulate cell signalling and membrane traffic. Finally, we provide a framework for how PI 3-phosphate metabolism is integrated into the cellular network. PMID:26888746

  9. Chemical and electronic interface structure of spray pyrolysis deposited undoped and Al-doped ZnO thin films on a commercial Cz-Si solar cell substrate

    Energy Technology Data Exchange (ETDEWEB)

    Gabas, M.; Ramos-Barrado, J.R. [Dpto. de Fisica Aplicada I, Lab. de Materiales y Superficies, Universidad de Malaga 29071 Malaga (Spain); Barrett, N.T. [CEA DSM/IRAMIS/SPCSI, CEA Saclay, 91191 Gif sur Yvette (France); Gota, S. [Laboratoire Leon Brillouin, UMR 012 CEA-CNRS CEA Saclay, 91191 Gif sur Yvette (France); Rojas, T.C. [Instituto de Ciencia de Materiales de Sevilla, CSIC, Americo Vespucio 49, 41092 Sevilla (Spain); Lopez-Escalante, M.C. [Isofoton S.A., Parque Tecnologico de Andalucia, Severo Ochoa, 50, 29590 Malaga (Spain)

    2009-08-15

    We have studied differences in the interface between undoped and Al-doped ZnO thin films deposited on commercial Si solar cell substrates. The undoped ZnO film is significantly thicker than the Al-doped film for the same deposition time. An extended silicate-like interface is present in both samples. Transmission electron microscopy (TEM) and photoelectron spectroscopy (PES) probe the presence of a zinc silicate and several Si oxides in both cases. Although Al doping improves the conductivity of ZnO, we present evidence for Al segregation at the interface during deposition on the Si substrate and suggest the presence of considerable fixed charge near the oxidized Si interface layer. The induced distortion in the valence band, compared to that of undoped ZnO, could be responsible for considerable reduction in the solar cell performance. (author)

  10. Recent Advances in Interface Engineering for Planar Heterojunction Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Wei Yin

    2016-06-01

    Full Text Available Organic-inorganic hybrid perovskite solar cells are considered as one of the most promising next-generation solar cells due to their advantages of low-cost precursors, high power conversion efficiency (PCE and easy of processing. In the past few years, the PCEs have climbed from a few to over 20% for perovskite solar cells. Recent developments demonstrate that perovskite exhibits ambipolar semiconducting characteristics, which allows for the construction of planar heterojunction (PHJ perovskite solar cells. PHJ perovskite solar cells can avoid the use of high-temperature sintered mesoporous metal oxides, enabling simple processing and the fabrication of flexible and tandem perovskite solar cells. In planar heterojunction materials, hole/electron transport layers are introduced between a perovskite film and the anode/cathode. The hole and electron transporting layers are expected to enhance exciton separation, charge transportation and collection. Further, the supporting layer for the perovskite film not only plays an important role in energy-level alignment, but also affects perovskite film morphology, which have a great effect on device performance. In addition, interfacial layers also affect device stability. In this review, recent progress in interfacial engineering for PHJ perovskite solar cells will be reviewed, especially with the molecular interfacial materials. The supporting interfacial layers for the optimization of perovskite films will be systematically reviewed. Finally, the challenges remaining in perovskite solar cells research will be discussed.

  11. Recent Advances in Interface Engineering for Planar Heterojunction Perovskite Solar Cells.

    Science.gov (United States)

    Yin, Wei; Pan, Lijia; Yang, Tingbin; Liang, Yongye

    2016-01-01

    Organic-inorganic hybrid perovskite solar cells are considered as one of the most promising next-generation solar cells due to their advantages of low-cost precursors, high power conversion efficiency (PCE) and easy of processing. In the past few years, the PCEs have climbed from a few to over 20% for perovskite solar cells. Recent developments demonstrate that perovskite exhibits ambipolar semiconducting characteristics, which allows for the construction of planar heterojunction (PHJ) perovskite solar cells. PHJ perovskite solar cells can avoid the use of high-temperature sintered mesoporous metal oxides, enabling simple processing and the fabrication of flexible and tandem perovskite solar cells. In planar heterojunction materials, hole/electron transport layers are introduced between a perovskite film and the anode/cathode. The hole and electron transporting layers are expected to enhance exciton separation, charge transportation and collection. Further, the supporting layer for the perovskite film not only plays an important role in energy-level alignment, but also affects perovskite film morphology, which have a great effect on device performance. In addition, interfacial layers also affect device stability. In this review, recent progress in interfacial engineering for PHJ perovskite solar cells will be reviewed, especially with the molecular interfacial materials. The supporting interfacial layers for the optimization of perovskite films will be systematically reviewed. Finally, the challenges remaining in perovskite solar cells research will be discussed. PMID:27347923

  12. Enhancement of open-circuit voltage and the fill factor in CdTe nanocrystal solar cells by using interface materials.

    Science.gov (United States)

    Zhu, Jiaoyan; Yang, Yuehua; Gao, Yuping; Qin, Donghuan; Wu, Hongbin; Hou, Lintao; Huang, Wenbo

    2014-09-12

    Interface states influence the operation of nanocrystal (NC) solar cell carrier transport, recombination and energetic mechanisms. In a typical CdTe NC solar cell with a normal structure of a ITO/p-CdTe NCs/n-acceptor (or without)/Al configuration, the contact between the ITO and CdTe is a non-ohm contact due to a different work function (for an ITO, the value is ~4.7 eV, while for CdTe NCs, the value is ~5.3 eV), which results in an energetic barrier at the ITO/CdTe interface and decreases the performance of the NC solar cells. This work investigates how interface materials (including Au, MoO(x) and C₆₀) affect the performance of NC solar cells. It is found that devices with interface materials have shown higher V(oc) than those without interface materials. For the case in which we used Au as an interface, we obtained a high open-circuit voltage of 0.65 V, coupled with a high fill factor (62%); this resulted in a higher energy conversion efficiency (ECE) of 5.3%, which showed a 30% increase in the ECE compared with those without the interlayer. The capacitance measurements indicate that the increased V(oc) in the case in which Au was used as the interface is likely due to good ohm contact between the Au's and the CdTe NCs' thin film, which decreases the energetic barrier at the ITO/CdTe interface. PMID:25140734

  13. Enhancement of open-circuit voltage and the fill factor in CdTe nanocrystal solar cells by using interface materials

    International Nuclear Information System (INIS)

    Interface states influence the operation of nanocrystal (NC) solar cell carrier transport, recombination and energetic mechanisms. In a typical CdTe NC solar cell with a normal structure of a ITO/p-CdTe NCs/n-acceptor (or without)/Al configuration, the contact between the ITO and CdTe is a non-ohm contact due to a different work function (for an ITO, the value is ∼4.7 eV, while for CdTe NCs, the value is ∼5.3 eV), which results in an energetic barrier at the ITO/CdTe interface and decreases the performance of the NC solar cells. This work investigates how interface materials (including Au, MoOx and C60) affect the performance of NC solar cells. It is found that devices with interface materials have shown higher Voc than those without interface materials. For the case in which we used Au as an interface, we obtained a high open-circuit voltage of 0.65 V, coupled with a high fill factor (62%); this resulted in a higher energy conversion efficiency (ECE) of 5.3%, which showed a 30% increase in the ECE compared with those without the interlayer. The capacitance measurements indicate that the increased Voc in the case in which Au was used as the interface is likely due to good ohm contact between the Au’s and the CdTe NCs’ thin film, which decreases the energetic barrier at the ITO/CdTe interface. (paper)

  14. Controlling the processable ZnO and polythiophene interface for dye-sensitized thin film organic solar cells

    International Nuclear Information System (INIS)

    Dye-sensitized thin film hybrid solar cells (DS thin film solar cell) were fabricated by one-pot process using solution processable zinc oxide (ZnO) precursor as electron acceptor, ester-functionalized polythiophene copolymer as donor and a squaraine dye. Incorporation of slight amount of ester functionality (6%) in the regioregular poly-3-hexylthiophene (P3HT) main chain leads to enhancement in the photoconversion efficiency of the ester functionalized polymer (P3HT-E) from 0.8% to about 1% (AM1.5, 100 mw/cm2). Photocurrent associated with both of the P3HT-E (400–650 nm) and the squaraine dye (650–750 nm) were observed in incident photon to current efficiency curve of the DS thin film solar cell. This proves that the ZnO/dye/P3HT-E interface could be fabricated by one-pot coating process from ternary mixture based on a ZnO precursor. - Highlights: • Single step and one pot fabrication of dye-sensitized polymer-ZnO hybrid solar cells. • In situ generation of ZnO using its diethyl zinc precursor. • Enhanced photovoltaic performance by introduction of ester functionalized polymers. • Demonstration of far-red photon harvesting by polymer-dye-ZnO ternary blend

  15. N-Glycosylation at the SynCAM (Synaptic Cell Adhesion Molecule) Immunoglobulin Interface Modulates Synaptic Adhesion

    Energy Technology Data Exchange (ETDEWEB)

    A Fogel; Y Li; Q Wang; T Lam; Y Modis; T Biederer

    2011-12-31

    Select adhesion molecules connect pre- and postsynaptic membranes and organize developing synapses. The regulation of these trans-synaptic interactions is an important neurobiological question. We have previously shown that the synaptic cell adhesion molecules (SynCAMs) 1 and 2 engage in homo- and heterophilic interactions and bridge the synaptic cleft to induce presynaptic terminals. Here, we demonstrate that site-specific N-glycosylation impacts the structure and function of adhesive SynCAM interactions. Through crystallographic analysis of SynCAM 2, we identified within the adhesive interface of its Ig1 domain an N-glycan on residue Asn(60). Structural modeling of the corresponding SynCAM 1 Ig1 domain indicates that its glycosylation sites Asn(70)/Asn(104) flank the binding interface of this domain. Mass spectrometric and mutational studies confirm and characterize the modification of these three sites. These site-specific N-glycans affect SynCAM adhesion yet act in a differential manner. Although glycosylation of SynCAM 2 at Asn(60) reduces adhesion, N-glycans at Asn(70)/Asn(104) of SynCAM 1 increase its interactions. The modification of SynCAM 1 with sialic acids contributes to the glycan-dependent strengthening of its binding. Functionally, N-glycosylation promotes the trans-synaptic interactions of SynCAM 1 and is required for synapse induction. These results demonstrate that N-glycosylation of SynCAM proteins differentially affects their binding interface and implicate post-translational modification as a mechanism to regulate trans-synaptic adhesion.

  16. Fuzzy control of the DC-DC converter used as power interface for a fuel cell

    International Nuclear Information System (INIS)

    In this paper it is analyzed a feed-forward fuzzy control for PWM control of the DC-DC converter using a fuel cell as energy source. For a dynamic load the fuel cell output voltage vary in large DC range and the high DC voltage stabilization can not be a difficult task. The advantages of the forward loop after the fuel cell output voltage concerning the stability and robustness of fuzzy control are compared with the best results obtained using a well designed proportional-integral control. The Simulink models for the used blocks, simulation results, and some design consideration are presented, too. (authors)

  17. Impact of micro-porous layer on liquid water distribution at the catalyst layer interface and cell performance in a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Tabe, Yutaka; Aoyama, Yusuke; Kadowaki, Kazumasa; Suzuki, Kengo; Chikahisa, Takemi

    2015-08-01

    In polymer electrolyte membrane fuel cells, a gas diffusion layer (GDL) with a micro-porous layer (MPL) gives better anti-flooding performance than GDLs without an MPL. To investigate the function and mechanism of the MPL to suppress water flooding, the liquid water distribution at the cathode catalyst layer (CL) surface are observed by a freezing method; in the method liquid water is immobilized in ice form by rapid freezing, followed by disassembling the cell for observations. The ice covered area is quantified by image processing and cells with and without an MPL are compared. The results show that the MPL suppresses water accumulation at the interface due to smaller pore size and finer contact with the CL, and this results in less water flooding. Investigation of ice formed after -10 °C cold start shutdowns and the temporary performance deterioration at ordinary temperatures also indicates a significant influence of the liquid water accumulating at the interface. The importance of the fine contact between CL and MPL, the relative absence of gaps, is demonstrated by a gas diffusion electrode (GDE) which is directly coated with catalyst ink on the surface of the MPL achieving finer contact of the layers.

  18. Shear Force at the Cell-Matrix Interface: Enhanced Analysis for Microfabricated Post Array Detectors

    OpenAIRE

    Lemmon, Christopher A.; Sniadecki, Nathan J.; Ruiz, Sami Alom; Tan, John L.; Romer, Lewis H.; Chen, Christopher S.

    2005-01-01

    The interplay of mechanical forces between the extracellular environment and the cytoskeleton drives development, repair, and senescence in many tissues. Quantitative definition of these forces is a vital step in understanding cellular mechanosensing. Microfabricated post array detectors (mPADs) provide direct measurements of cell-generated forces during cell adhesion to extracellular matrix. A new approach to mPAD post labeling, volumetric imaging, and an analysis of post bending mechanics d...

  19. Extremely sensitive light-induced reorientation in nondoped nematic liquid crystal cells due to photoelectric activation of the interface

    International Nuclear Information System (INIS)

    We report an investigation of the extremely sensitive molecular reorientation in pure nematic liquid crystal film induced by the combined application of low dc electric field (less than 0.1 V/μm) and very low intensity optical irradiation (few mW/cm2). The effect is observed in planar cells of well-known commercial nematic mixture (E7) aligned with rubbed polyvinyl alcohol layers, which exhibit photorefractive-like effect. We analyze the dependence of the photoinduced changes in birefringence upon the applied dc voltage and the light intensity. According to our results we believe that the effect is due to photoinduced recombination of the opposite charged carriers accumulated near the interface. In the low dc voltage regime (a few volts) the voltage mainly drops on the electric double layers at the interfaces as a consequence of dc field collected charge carriers from liquid crystalline and polymeric films to the border surfaces. Irradiation with appropriate wavelength reduces the interfacial charges density, because of photoinduced carrier injection and recombination processes, and consequently, induces a relocation of the electric field from the surface to the liquid crystal bulk. The light-induced additional electric field component in the nematic film results in a lowering of the Freedericksz threshold or an enhanced molecular reorientation

  20. Aberration-corrected transmission electron microscopy analyses of GaAs/Si interfaces in wafer-bonded multi-junction solar cells

    International Nuclear Information System (INIS)

    Aberration-corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) investigations have been applied to investigate the structure and composition fluctuations near interfaces in wafer-bonded multi-junction solar cells. Multi-junction solar cells are of particular interest since efficiencies well above 40% have been obtained for concentrator solar cells which are based on III-V compound semiconductors. In this methodologically oriented investigation, we explore the potential of combining aberration-corrected high-angle annular dark-field STEM imaging (HAADF-STEM) with spectroscopic techniques, such as EELS and energy-dispersive X-ray spectroscopy (EDXS), and with high-resolution transmission electron microscopy (HR-TEM), in order to analyze the effects of fast atom beam (FAB) and ion beam bombardment (IB) activation treatments on the structure and composition of bonding interfaces of wafer-bonded solar cells on Si substrates. Investigations using STEM/EELS are able to measure quantitatively and with high precision the widths and the fluctuations in element distributions within amorphous interface layers of nanometer extensions, including those of light elements. Such measurements allow the control of the activation treatments and thus support assessing electrical conductivity phenomena connected with impurity and dopant distributions near interfaces for optimized performance of the solar cells. - Highlights: • Aberration-corrected TEM and EELS reveal structural and elemental profiles across GaAs/Si bond interfaces in wafer-bonded GaInP/GaAs/Si - multi-junction solar cells. • Fluctuations in elemental concentration in nanometer-thick amorphous interface layers, including the disrubutions of light elements, are measured using EELS. • The projected widths of the interface layers are determined on the atomic scale from STEM-HAADF measurements. • The effects of atom and ion beam activation treatment on the bonding

  1. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces

    International Nuclear Information System (INIS)

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions

  2. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Benjamin J. [Department of Physics and Astronomy, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089-0484 (United States); El-Naggar, Mohamed Y., E-mail: mnaggar@usc.edu [Department of Physics and Astronomy, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089-0484 (United States); Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-0484 (United States); Department of Chemistry, University of Southern California, Los Angeles, California 90089-0484 (United States)

    2015-06-15

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions.

  3. Optical chirality of protonated tetraphenylporphyrin J-aggregate formed at the liquid liquid interface in a centrifugal liquid membrane cell

    Science.gov (United States)

    Wada, Sayaka; Fujiwara, Kazuhiko; Monjushiro, Hideaki; Watarai, Hitoshi

    2007-09-01

    J-aggregation of an achiral hydrophobic porphyrin, 5,10,15,20-tetraphenylporphyrin (H2TPP), at a toluene-4 M sulfuric acid interface was studied by a centrifugal liquid membrane-circular dichroism (CLM-CD) method. It was found for the first time that the exciton chirality sign of the interfacial J-aggregate of H4TPP2+ was affected by the rotational direction of the cylindrical CLM cell: a negative sign for clockwise (CW) rotation and a positive sign for anticlockwise (ACW) rotation. The sign of the measured optical chirality also depended on the injection position of the H2TPP stock solution in the rotating cell. Furthermore, it was observed that the rotational linear velocity of the aqueous phase was faster than that of the toluene phase, when the CLM cell was rotated at 7000 rpm. The effects of rotational direction and sample injection position on the optical chirality were overcome by the effect of chiral counter-ions such as (+)- or (-)-camphorsulfonic anions. From the observed results, a possible mechanism for the generation of the optical chirality of the interfacial J-aggregate was proposed taking into account an interfacial shear force and the spreading direction of H2TPP in the toluene phase.

  4. Generation of ESC-derived Mouse Airway Epithelial Cells Using Decellularized Lung Scaffolds.

    Science.gov (United States)

    Shojaie, Sharareh; Lee, Joyce; Wang, Jinxia; Ackerley, Cameron; Post, Martin

    2016-01-01

    Lung lineage differentiation requires integration of complex environmental cues that include growth factor signaling, cell-cell interactions and cell-matrix interactions. Due to this complexity, recapitulation of lung development in vitro to promote differentiation of stem cells to lung epithelial cells has been challenging. In this protocol, decellularized lung scaffolds are used to mimic the 3-dimensional environment of the lung and generate stem cell-derived airway epithelial cells. Mouse embryonic stem cell are first differentiated to the endoderm lineage using an embryoid body (EB) culture method with activin A. Endoderm cells are then seeded onto decellularized scaffolds and cultured at air-liquid interface for up to 21 days. This technique promotes differentiation of seeded cells to functional airway epithelial cells (ciliated cells, club cells, and basal cells) without additional growth factor supplementation. This culture setup is defined, serum-free, inexpensive, and reproducible. Although there is limited contamination from non-lung endoderm lineages in culture, this protocol only generates airway epithelial populations and does not give rise to alveolar epithelial cells. Airway epithelia generated with this protocol can be used to study cell-matrix interactions during lung organogenesis and for disease modeling or drug-discovery platforms of airway-related pathologies such as cystic fibrosis. PMID:27214388

  5. Reactivity of the cement-bentonite interface with alkaline solutions using transport cells

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Raul [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Cuevas, Jaime [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain)]. E-mail: jaime.cuevas@uam.es; Sanchez, Laura [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Villa, Raquel Vigil de la [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Leguey, Santiago [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain)

    2006-06-15

    Clayey formations are considered as suitable host rocks to develop a Deep Geological Repository (DGR) for nuclear wastes. A concrete ring, located between the clayey formation and the bentonite barrier, is needed as structural support for the galleries. This material will act as a source of alkaline fluids when the formation's pore water saturates the system. This investigation evaluates the performance of the concrete-bentonite system by means of both geochemical codes and experimental results. A column made of compacted bentonite from La Serrata (Almeria, Spain) (1.4 g/cm{sup 3}, dry density) was held in contact with an ordinary Portland cement (OPC) mortar. Two alkaline solutions (Ca(OH){sub 2} saturated and NaOH 0.25 M) were injected from the mortar's side at 25, 60 and 120 deg. C. The permeability of the system and the effluent fluid composition were determined periodically. Finally, the solid phase was sampled and analyzed after 1 year of treatment. Ca(OH){sub 2} saturated fluids does not alter the mineralogy over the experiment time scale. NaOH fluids produced minor changes at 60-25 deg. C but at 120 deg. C a thin tobermorite layer of 1.5 mm precipitates in the clay aggregate surfaces at the interface. After this layer, analcime nucleates in heterogeneous patches affecting the whole compacted bentonite probe (2 cm thickness). The use of the PHREEQC code thermodynamic approach predicts the mineralogical transformations. However, it is necessary to introduce kinetic laws and to consider the existence of stagnant zones in the model in order to simulate the heterogeneous spatial alteration observed.

  6. Enhanced photon management in silicon thin film solar cells with different front and back interface texture.

    Science.gov (United States)

    Tamang, Asman; Hongsingthong, Aswin; Jovanov, Vladislav; Sichanugrist, Porponth; Khan, Bakhtiar A; Dewan, Rahul; Konagai, Makoto; Knipp, Dietmar

    2016-01-01

    Light trapping and photon management of silicon thin film solar cells can be improved by a separate optimization of the front and back contact textures. A separate optimization of the front and back contact textures is investigated by optical simulations taking realistic device geometries into consideration. The optical simulations are confirmed by experimentally realized 1 μm thick microcrystalline silicon solar cells. The different front and back contact textures lead to an enhancement of the short circuit current by 1.2 mA/cm(2) resulting in a total short circuit current of 23.65 mA/cm(2) and an energy conversion efficiency of 8.35%. PMID:27481226

  7. Enhanced photon management in silicon thin film solar cells with different front and back interface texture

    Science.gov (United States)

    Tamang, Asman; Hongsingthong, Aswin; Jovanov, Vladislav; Sichanugrist, Porponth; Khan, Bakhtiar A.; Dewan, Rahul; Konagai, Makoto; Knipp, Dietmar

    2016-08-01

    Light trapping and photon management of silicon thin film solar cells can be improved by a separate optimization of the front and back contact textures. A separate optimization of the front and back contact textures is investigated by optical simulations taking realistic device geometries into consideration. The optical simulations are confirmed by experimentally realized 1 μm thick microcrystalline silicon solar cells. The different front and back contact textures lead to an enhancement of the short circuit current by 1.2 mA/cm2 resulting in a total short circuit current of 23.65 mA/cm2 and an energy conversion efficiency of 8.35%.

  8. Silicon nitride anti-reflection coating on the glass and transparent conductive oxide interface for thin film solar cells and modules

    Science.gov (United States)

    Iwahashi, T.; Morishima, M.; Fujibayashi, T.; Yang, R.; Lin, J.; Matsunaga, D.

    2015-10-01

    Anti-reflection coating (ARC) is well known as an important technique to enhance solar cell performance. Typical ARC has been applied on the glass surface to reduce light reflection loss at the air/glass interface. However, reflection loss occurs not only at glass surface but also at other interfaces such as glass/transparent conductive oxide (TCO) interface. The refractive index of SiNx is tunable from 1.6 to 2.7, and the range from 1.7 to 2.0 is suitable for ARC at glass/TCO interface. In this study, we examined the AR effect of silicon nitride (SiNx) deposited by plasma enhanced chemical vapor deposition at the glass/TCO interface with thin film silicon solar cell and module. Reflectivity reduction of 1.6% for glass/ZnO substrate has been obtained with optimal SiNx layer, which contribute 2.0% gain in cell efficiency. Besides, we also confirmed the relative efficiency gain of around 2% for large-sized solar module, leading to a world-record large area stabilized module conversion efficiency of 12.34%.

  9. The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells

    OpenAIRE

    Ahmad Agha, Nezha; Willumeit-Römer, Regine; Laipple, Daniel; Luthringer, Bérengère; Feyerabend, Frank

    2016-01-01

    Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys) is studied for up to 14 days. Se...

  10. NeuroArray: A Universal Interface for Patterning and Interrogating Neural Circuitry with Single Cell Resolution

    OpenAIRE

    Li, Wei; Xu, Zhen; Huang, Junzhe; Lin, Xudong; Luo, Rongcong; Chen, Chia-Hung; Shi, Peng

    2014-01-01

    Recreation of neural network in vitro with designed topology is a valuable tool to decipher how neurons behave when interacting in hierarchical networks. In this study, we developed a simple and effective platform to pattern primary neurons in array formats for interrogation of neural circuitry with single cell resolution. Unlike many surface-chemistry-based patterning methods, our NeuroArray technique is specially designed to accommodate neuron's polarized morphologies to make regular arrays...

  11. Human Coronary Artery Smooth Muscle Cell Responses to Bioactive Polyelectrolyte Multilayer Interfaces

    Directory of Open Access Journals (Sweden)

    Robert G. Newcomer

    2011-01-01

    Full Text Available Under normal physiological conditions, mature human coronary artery smooth muscle cells (hCASMCs exhibit a “contractile” phenotype marked by low rates of proliferation and protein synthesis, but these cells possess the remarkable ability to dedifferentiate into a “synthetic” phenotype when stimulated by conditions of pathologic stress. A variety of polyelectrolyte multilayer (PEMU films are shown here to exhibit bioactive properties that induce distinct responses from cultured hCASMCs. Surfaces terminated with Nafion or poly(styrenesulfonic acid (PSS induce changes in the expression and organization of intracellular proteins, while a hydrophilic, zwitterionic copolymer of acrylic acid and 3-[2-(acrylamido-ethyl dimethylammonio] propane sulfonate (PAA-co-PAEDAPS is resistant to cell attachment and suppresses the formation of key cytoskeletal components. Differential expression of heat shock protein 90 and actin is observed, in terms of both their magnitude and cellular localization, and distinct cytoplasmic patterns of vimentin are seen. The ionophore A23187 induces contraction in confluent hCASMC cultures on Nafion-terminated surfaces. These results demonstrate that PEMU coatings exert direct effects on the cytoskeletal organization of attaching hCASMCs, impeding growth in some cases, inducing changes consistent with phenotypic modulation in others, and suggesting potential utility for PEMU surfaces as a coating for coronary artery stents and other implantable medical devices.

  12. SAP(E) - A cell-penetrating polyproline helix at lipid interfaces.

    Science.gov (United States)

    Franz, Johannes; Lelle, Marco; Peneva, Kalina; Bonn, Mischa; Weidner, Tobias

    2016-09-01

    Cell-penetrating peptides (CPPs) are short membrane-permeating amino acid sequences that can be used to deliver cargoes, e.g. drugs, into cells. The mechanism for CPP internalization is still subject of ongoing research. An interesting family of CPPs is the sweet arrow peptides - SAP(E) - which are known to adopt a polyproline II helical secondary structure. SAP(E) peptides stand out among CPPs because they carry a net negative charge while most CPPs are positively charged, the latter being conducive to electrostatic interaction with generally negatively charged membranes. For SAP(E)s, an internalization mechanism has been proposed, based on polypeptide aggregation on the cell surface, followed by an endocytic uptake. However, this process has not yet been observed directly - since peptide-membrane interactions are inherently difficult to monitor on a molecular scale. Here, we use sum frequency generation (SFG) vibrational spectroscopy to investigate molecular interactions of SAP(E) with differently charged model membranes, in both mono- and bi-layer configurations. The data suggest that the initial binding mechanism is accompanied by structural changes of the peptide. Also, the peptide-model membrane interaction depends on the charge of the lipid headgroup with phosphocholine being a favorable binding site. Moreover, while direct penetration has also been observed for some CPPs, the spectroscopy reveals that for SAP(E), its interaction with model membranes remains limited to the headgroup region, and insertion into the hydrophobic core of the lipid layer does not occur. PMID:27237727

  13. Studying the glial cell response to biomaterials and surface topography for improving the neural electrode interface

    Science.gov (United States)

    Ereifej, Evon S.

    Neural electrode devices hold great promise to help people with the restoration of lost functions, however, research is lacking in the biomaterial design of a stable, long-term device. Current devices lack long term functionality, most have been found unable to record neural activity within weeks after implantation due to the development of glial scar tissue (Polikov et al., 2006; Zhong and Bellamkonda, 2008). The long-term effect of chronically implanted electrodes is the formation of a glial scar made up of reactive astrocytes and the matrix proteins they generate (Polikov et al., 2005; Seil and Webster, 2008). Scarring is initiated when a device is inserted into brain tissue and is associated with an inflammatory response. Activated astrocytes are hypertrophic, hyperplastic, have an upregulation of intermediate filaments GFAP and vimentin expression, and filament formation (Buffo et al., 2010; Gervasi et al., 2008). Current approaches towards inhibiting the initiation of glial scarring range from altering the geometry, roughness, size, shape and materials of the device (Grill et al., 2009; Kotov et al., 2009; Kotzar et al., 2002; Szarowski et al., 2003). Literature has shown that surface topography modifications can alter cell alignment, adhesion, proliferation, migration, and gene expression (Agnew et al., 1983; Cogan et al., 2005; Cogan et al., 2006; Merrill et al., 2005). Thus, the goals of the presented work are to study the cellular response to biomaterials used in neural electrode fabrication and assess surface topography effects on minimizing astrogliosis. Initially, to examine astrocyte response to various materials used in neural electrode fabrication, astrocytes were cultured on platinum, silicon, PMMA, and SU-8 surfaces, with polystyrene as the control surface. Cell proliferation, viability, morphology and gene expression was measured for seven days in vitro. Results determined the cellular characteristics, reactions and growth rates of astrocytes

  14. Pathway to low-cost metallization of silicon solar cell through understanding of the silicon metal interface and plating chemistry

    International Nuclear Information System (INIS)

    Metallization is crucial to silicon solar cell performance. It is the second most expensive process step in the fabrication of a solar cell. In order to reduce the cost of solar cell, the metallization cost has to be cut down by using less metal without compromising the efficiency. Screen-printing has been used in metallizing the commercial solar cell because of the high throughput and low cost at the expense of performance. However, because of the variability in the screen-printed gridlines, the amount of Ag metal used cannot be controlled. More so, the dependence of the contact resistance on doping necessitates the use of low sheet resistance emitters, which exacerbates losses in the blue response and hence the efficiency. To balance the contact resistance and improve blue response, several approaches have been undertaken including, use of Ag pastes incorporating nanoparticle glass frits that will not diffuse excessively into a lightly doped emitter, Ni plating on lightly doped emitter through SiNx dielectric plus NiSi formation followed by Cu and/or Ag plating, light induced plating (LIP) of Ag or Cu on fired through dielectric metal seed layers formed by aerosol or inkjet or screen-printing. All these approaches require excellent adhesion and gridline conductivity to minimize the total series resistance, which impedes the collection of electrons. This paper presents the issues and the pathway to achieving high efficiency using low cost metallization technology involving inkjet-printed Ag fine gridline having 38 μm width and 3 μm height fired through the SiNx followed by Ni and Cu plating. A comprehensive analysis of silicon/metal interface, using high precision microscopy, has shown that the investigated metallization technology is appropriate for the longevity of the device

  15. Grazing incidence X-ray fluorescence analysis of buried interfaces in periodically structured crystalline silicon thin-film solar cells

    International Nuclear Information System (INIS)

    We present grazing incidence X-ray fluorescence (GIXRF) experiments on 3D periodically textured interfaces of liquid phase crystallized silicon thin-film solar cells on glass. The influence of functional layers (SiOx or SiOx/SiCx) - placed between glass substrate and silicon during crystallization - on the final carbon and oxygen contaminations inside the silicon was analyzed. Baring of the buried structured silicon surface prior to GIXRF measurement was achieved by removal of the original nano-imprinted glass substrate by wet-chemical etching. A broad angle of incidence distribution was determined for the X-ray radiation impinging on this textured surface. Optical simulations were performed in order to estimate the incident radiation intensity on the structured surface profile considering total reflection and attenuation effects. The results indicate a much lower contamination level for SiOx compared to the SiOx/SiCx interlayers, and about 25% increased contamination when comparing structured with planar silicon layers, both correlating with the corresponding solar cell performances. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. SXPS characterization of a donor / acceptor hetero junction for organic solar cells: High photovoltage at the merocyanine / fullerene interface

    Energy Technology Data Exchange (ETDEWEB)

    Mankel, Eric; Reckers, Philip; Konrad, Ludmila; Hein, Corinna; Mayer, Thomas; Jaegermann, Wolfram [Technische Universitaet Darmstadt, Materials Science Institute, Surface Science Division, Petersenstrasse 32, 64287 Darmstadt (Germany)

    2011-07-01

    Novel absorber molecules are investigated for high efficient organic solar cells. Especially merocyanines provide high photovoltages as donor materials in photoactive organic hetero junction cells. The electronic alignment of a merocyanine/fullerene hetero junction is presented. The band diagram was determined by synchrotron induced photoelectron spectroscopy on in situ stepwise deposited fullerene on a merocyanine layer using the TGM7 dipole beamline at Bessy II. The merocyanine/fullerene HOMO offset is determined to be 850 meV leading to a high LUMO offset, the driving force for exciton splitting. In situ bias illumination of the interface with 150 W/m{sup 2} of a halogen lamp leads to a reversible shift of the C{sub 60} emission features of about 800 meV, indicating a high photovoltage. The height of the photovoltage depends on the fullerene layer thickness. It starts at 200 mV for submonolayer coverage and increases up to approximately 1V for coverages of some ten nanometers.

  17. Grazing incidence X-ray fluorescence analysis of buried interfaces in periodically structured crystalline silicon thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Eisenhauer, David; Preidel, Veit; Becker, Christiane [Young Investigator Group Nanostructured Silicon for Photovoltaic and Photonic Implementations (Nano-SIPPE), Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Pollakowski, Beatrix; Beckhoff, Burkhard [Physikalisch-Technische Bundesanstalt, Berlin (Germany); Baumann, Jonas; Kanngiesser, Birgit [Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin (Germany); Amkreutz, Daniel; Rech, Bernd [Institut Silizium Photovoltaik, Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Back, Franziska; Rudigier-Voigt, Eveline [SCHOTT AG, Mainz (Germany)

    2015-03-01

    We present grazing incidence X-ray fluorescence (GIXRF) experiments on 3D periodically textured interfaces of liquid phase crystallized silicon thin-film solar cells on glass. The influence of functional layers (SiO{sub x} or SiO{sub x}/SiC{sub x}) - placed between glass substrate and silicon during crystallization - on the final carbon and oxygen contaminations inside the silicon was analyzed. Baring of the buried structured silicon surface prior to GIXRF measurement was achieved by removal of the original nano-imprinted glass substrate by wet-chemical etching. A broad angle of incidence distribution was determined for the X-ray radiation impinging on this textured surface. Optical simulations were performed in order to estimate the incident radiation intensity on the structured surface profile considering total reflection and attenuation effects. The results indicate a much lower contamination level for SiO{sub x} compared to the SiO{sub x}/SiC{sub x} interlayers, and about 25% increased contamination when comparing structured with planar silicon layers, both correlating with the corresponding solar cell performances. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Reactivity of nitrate and organic acids at the concrete–bitumen interface of a nuclear waste repository cell

    Energy Technology Data Exchange (ETDEWEB)

    Bertron, A., E-mail: bertron@insa-toulouse.fr [Université de Toulouse (France); UPS, INSA (France); LMDC (Laboratoire Matériaux et Durabilité des Constructions), 135, avenue de Rangueil, F-31 077, Toulouse Cedex 04 (France); Jacquemet, N. [Université de Toulouse (France); UPS, INSA (France); LMDC (Laboratoire Matériaux et Durabilité des Constructions), 135, avenue de Rangueil, F-31 077, Toulouse Cedex 04 (France); Erable, B. [Université de Toulouse (France); INPT, UPS (France); CNRS, Laboratoire de Génie Chimique, 4, Allée Emile Monso, F-31030 Toulouse (France); Sablayrolles, C. [Université de Toulouse (France); INP (France); LCA (Laboratoire de Chimie Agro-Industrielle), ENSIACET, 4 allée Emile Monso, BP 44 362, 31432 Toulouse Cedex 4 (France); INRA (France); LCA (Laboratoire de Chimie Agro-Industrielle), F-31029 Toulouse (France); Escadeillas, G. [Université de Toulouse (France); UPS, INSA (France); LMDC (Laboratoire Matériaux et Durabilité des Constructions), 135, avenue de Rangueil, F-31 077, Toulouse Cedex 04 (France); Albrecht, A. [Andra, 1-7, rue Jean-Monnet, 92298 Châtenay-Malabry (France)

    2014-03-01

    Highlights: • Interactions of cement paste and organic acid–nitrate solutions were investigated. • Cement leaching imposed alkaline pH (>10) very rapidly in the liquid media. • Acetic acid action on cement paste was similar to that of classical leaching. • Oxalic acid attack formed Ca-oxalate salts; organic matter in solution decreased. • Nitrate was stable under abiotic conditions and with organic matter. - Abstract: This study investigates the fate of nitrate and organic acids at the bitumen–concrete interface within repository cell for long-lived, intermediate-level, radioactive wastes. The interface was simulated by a multiphase system in which cementitious matrices (CEM V cement paste specimens) were exposed to bitumen model leachates consisting of nitrates and acetic acid with and without oxalic acid, chemical compounds likely to be released by bitumen. Leaching experiments were conducted with daily renewal of the solutions in order to accelerate reactions. The concentrations of anions (acetate, oxalate, nitrate, and nitrite) and cations (calcium, potassium) and the pH were monitored over time. Mineralogical changes of the cementitious matrices were analysed by XRD. The results confirmed the stability of nitrates in the abiotic conditions of the experiments. The action of acetic acid on the cementitious matrix was similar to that of ordinary leaching in the absence of organic acids (i.e. carried out with water or strong acids); no specific interaction was detected between acetate and cementitious cations. The reaction of oxalic acid with the cementitious phases led to the precipitation of calcium oxalate salts in the outer layer of the matrix. The concentration of oxalate was reduced by 65% inside the leaching medium.

  19. Reactivity of nitrate and organic acids at the concrete–bitumen interface of a nuclear waste repository cell

    International Nuclear Information System (INIS)

    Highlights: • Interactions of cement paste and organic acid–nitrate solutions were investigated. • Cement leaching imposed alkaline pH (>10) very rapidly in the liquid media. • Acetic acid action on cement paste was similar to that of classical leaching. • Oxalic acid attack formed Ca-oxalate salts; organic matter in solution decreased. • Nitrate was stable under abiotic conditions and with organic matter. - Abstract: This study investigates the fate of nitrate and organic acids at the bitumen–concrete interface within repository cell for long-lived, intermediate-level, radioactive wastes. The interface was simulated by a multiphase system in which cementitious matrices (CEM V cement paste specimens) were exposed to bitumen model leachates consisting of nitrates and acetic acid with and without oxalic acid, chemical compounds likely to be released by bitumen. Leaching experiments were conducted with daily renewal of the solutions in order to accelerate reactions. The concentrations of anions (acetate, oxalate, nitrate, and nitrite) and cations (calcium, potassium) and the pH were monitored over time. Mineralogical changes of the cementitious matrices were analysed by XRD. The results confirmed the stability of nitrates in the abiotic conditions of the experiments. The action of acetic acid on the cementitious matrix was similar to that of ordinary leaching in the absence of organic acids (i.e. carried out with water or strong acids); no specific interaction was detected between acetate and cementitious cations. The reaction of oxalic acid with the cementitious phases led to the precipitation of calcium oxalate salts in the outer layer of the matrix. The concentration of oxalate was reduced by 65% inside the leaching medium

  20. Design, construction and start up by Air Liquide of two 18 kW at 45 K helium refrigerators for the new CERN accelerator (LHC)

    CERN Document Server

    Dauguet, P; Delcayre, F; Ghisolfi, A; Gistau-Baguer, Guy M; Guerin, C A; Hilbert, B; Marot, G; Monneret, E

    2004-01-01

    CERN in Switzerland is presently building a new particle accelerator labeled as the LHC. This 27 km accelerator will, for the first time at such a large scale, operate at cryogenic temperatures with superconducting magnets and radio-frequency cavities. For that purpose, Air Liquide has designed, constructed and started up two custom designed refrigerators. The cryogenic power of each of these refrigerators is equivalent to 18 kW at 4.5 K. In order to produce the cryogenic power requested by the LHC accelerator at the different temperature levels with a very high efficiency, a custom design thermodynamic cycle has been chosen. This cycle, the major components of the refrigerators and the results obtained during the reception tests of the refrigerators are presented in this paper.

  1. Interface models

    DEFF Research Database (Denmark)

    Ravn, Anders P.; Staunstrup, Jørgen

    1994-01-01

    This paper proposes a model for specifying interfaces between concurrently executing modules of a computing system. The model does not prescribe a particular type of communication protocol and is aimed at describing interfaces between both software and hardware modules or a combination of the two....... The model describes both functional and timing properties of an interface...

  2. Effective improvement of interface modified strontium titanate based solid oxide fuel cell anodes by infiltration with nano-sized palladium and gadolinium-doped cerium oxide

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Høgh, Jens Valdemar Thorvald; Zhang, Wei; Blennow Tullmar, Peter; Bonanos, Nikolaos; Boukamp, Bernard A.

    2013-01-01

    The development of low temperature solid oxide fuel cell (SOFC) anodes by infiltration of Pd/Gd-doped cerium oxide (CGO) electrocatalysts in Nb-doped SrTiO3 (STN) backbones has been investigated. Modification of the electrode/electrolyte interface by thin layer of spin-coated CGO (400-500 nm) con...

  3. Adhesion frequency assay for in situ kinetics analysis of cross-junctional molecular interactions at the cell-cell interface.

    Science.gov (United States)

    Zarnitsyna, Veronika I; Zhu, Cheng

    2011-01-01

    The micropipette adhesion assay was developed in 1998 to measure two-dimensional (2D) receptor-ligand binding kinetics. The assay uses a human red blood cell (RBC) as adhesion sensor and presenting cell for one of the interacting molecules. It employs micromanipulation to bring the RBC into contact with another cell that expresses the other interacting molecule with precisely controlled area and time to enable bond formation. The adhesion event is detected as RBC elongation upon pulling the two cells apart. By controlling the density of the ligands immobilized on the RBC surface, the probability of adhesion is kept in mid-range between 0 and 1. The adhesion probability is estimated from the frequency of adhesion events in a sequence of repeated contact cycles between the two cells for a given contact time. Varying the contact time generates a binding curve. Fitting a probabilistic model for receptor-ligand reaction kinetics to the binding curve returns the 2D affinity and off-rate. The assay has been validated using interactions of Fcγ receptors with IgG Fc, selectins with glycoconjugate ligands, integrins with ligands, homotypical cadherin binding, T cell receptor and coreceptor with peptide-major histocompatibility complexes. The method has been used to quantify regulations of 2D kinetics by biophysical factors, such as the membrane microtopology, membrane anchor, molecular orientation and length, carrier stiffness, curvature, and impingement force, as well as biochemical factors, such as modulators of the cytoskeleton and membrane microenvironment where the interacting molecules reside and the surface organization of these molecules. The method has also been used to study the concurrent binding of dual receptor-ligand species, and trimolecular interactions using a modified model. The major advantage of the method is that it allows study of receptors in their native membrane environment. The results could be very different from those obtained using purified

  4. Nanoscale investigation of the interface situation of plated nickel and thermally formed nickel silicide for silicon solar cell metallization

    International Nuclear Information System (INIS)

    Highlights: • Adhesion of metallization of fully plated nickel–copper contacts on silicon solar cells can be achieved by formation of nickel silicide at the cost of degraded cell performance. • Understanding of silicide growth mechanisms and controlled growth may lead to high performance together with excellent adhesion. • Silicide formation is well known from CMOS production from PVD-Ni on flat surfaces. Yet the deposition methods and therefore layer characteristics and the surface topography are different for plated metallization. • TEM analysis is performed for differently processed samples. • A nickel silicide growth model is created for plated Ni on textured silicon solar cells. - Abstract: In the context of nickel silicide formation from plated nickel layers for solar cell metallization, there are several open questions regarding contact adhesion and electrical properties. Nanoscale characterization by transmission electron microscopy has been employed to support these investigations. Interfacial oxides and silicide phases were investigated on differently prepared samples by different analytical methods associated with transmission electron microscopy analysis. Processing variations included the pre-treatment of samples before nickel plating, the used plating solution and the thermal budget for the nickel–silicon solid-state reaction. It was shown that interface oxides of only few nm thickness on both silicon and nickel silicide are present on the samples, depending on the chosen process sequence, which have been shown to play an important role in adhesion of nickel on silicide in an earlier publication. From sample pretreatment variations, conclusions about the role of an interfacial oxide in silicide formation and its influence on phase formation were drawn. Such an oxide layer hinders silicide formation except for pinhole sites. This reduces the availability of Ni and causes a silicide with low Ni content to form. Without an interfacial oxide

  5. An imbalance between innate and adaptive immune cells at the maternal-fetal interface occurs prior to endotoxin-induced preterm birth.

    Science.gov (United States)

    Arenas-Hernandez, Marcia; Romero, Roberto; St Louis, Derek; Hassan, Sonia S; Kaye, Emily B; Gomez-Lopez, Nardhy

    2016-07-01

    Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. A transition from an anti-inflammatory state to a pro-inflammatory state in the mother and at the maternal-fetal interface has been implicated in the pathophysiology of microbial-induced preterm labor. However, it is unclear which immune cells mediate this transition. We hypothesized that an imbalance between innate and adaptive immune cells at the maternal-fetal interface will occur prior to microbial-induced preterm labor. Using an established murine model of endotoxin-induced PTB, our results demonstrate that prior to delivery there is a reduction of CD4+ regulatory T cells (Tregs) in the uterine tissues. This reduction is neither linked to a diminished number of Tregs in the spleen, nor to an impaired production of IL10, CCL17, or CCL22 by the uterine tissues. Endotoxin administration to pregnant mice does not alter effector CD4+ T cells at the maternal-fetal interface. However, it causes an imbalance between Tregs (CD4+ and CD8+), effector CD8+ T cells, and Th17 cells in the spleen. In addition, endotoxin administration to pregnant mice leads to an excessive production of CCL2, CCL3, CCL17, and CCL22 by the uterine tissues as well as abundant neutrophils. This imbalance in the uterine microenvironment is accompanied by scarce APC-like cells such as macrophages and MHC II+ neutrophils. Collectively, these results demonstrate that endotoxin administration to pregnant mice causes an imbalance between innate and adaptive immune cells at the maternal-fetal interface. PMID:25849119

  6. Nanoscale investigation of the interface situation of plated nickel and thermally formed nickel silicide for silicon solar cell metallization

    Science.gov (United States)

    Mondon, A.; Wang, D.; Zuschlag, A.; Bartsch, J.; Glatthaar, M.; Glunz, S. W.

    2014-12-01

    In the context of nickel silicide formation from plated nickel layers for solar cell metallization, there are several open questions regarding contact adhesion and electrical properties. Nanoscale characterization by transmission electron microscopy has been employed to support these investigations. Interfacial oxides and silicide phases were investigated on differently prepared samples by different analytical methods associated with transmission electron microscopy analysis. Processing variations included the pre-treatment of samples before nickel plating, the used plating solution and the thermal budget for the nickel-silicon solid-state reaction. It was shown that interface oxides of only few nm thickness on both silicon and nickel silicide are present on the samples, depending on the chosen process sequence, which have been shown to play an important role in adhesion of nickel on silicide in an earlier publication. From sample pretreatment variations, conclusions about the role of an interfacial oxide in silicide formation and its influence on phase formation were drawn. Such an oxide layer hinders silicide formation except for pinhole sites. This reduces the availability of Ni and causes a silicide with low Ni content to form. Without an interfacial oxide a continuous nickel silicide of greater depth, polycrystalline modification and expected phase according to thermal budget is formed. Information about the nature of silicide growth on typical solar cell surfaces could be obtained from silicide phase and geometric observations, which were supported by FIB tomography. The theory of isotropic NiSi growth and orientation dependent NiSi2 growth was derived. By this, a very well performing low-cost metallization for silicon solar cells has been brought an important step closer to industrial introduction.

  7. Bioelectrochemical interface engineering: toward the fabrication of electrochemical biosensors, biofuel cells, and self-powered logic biosensors.

    Science.gov (United States)

    Zhou, Ming; Dong, Shaojun

    2011-11-15

    Over the past decade, researchers have devoted considerable attention to the integration of living organisms with electronic elements to yield bioelectronic devices. Not only is the integration of DNA, enzymes, or whole cells with electronics of scientific interest, but it has many versatile potential applications. Researchers are using these ideas to fabricate biosensors for analytical applications and to assemble biofuel cells (BFCs) and biomolecule-based devices. Other research efforts include the development of biocomputing systems for information processing. In this Account, we focus on our recent progress in engineering at the bioelectrochemical interface (BECI) for the rational design and construction of important bioelectronic devices, ranging from electrochemical (EC-) biosensors to BFCs, and self-powered logic biosensors. Hydrogels and sol-gels provide attractive materials for the immobilization of enzymes because they make EC-enzyme biosensors stable and even functional in extreme environments. We use a layer-by-layer (LBL) self-assembly technique to fabricate multicomponent thin films on the BECI at the nanometer scale. Additionally, we demonstrate how carbon nanomaterials have paved the way for new and improved EC-enzyme biosensors. In addition to the widely reported BECI-based electrochemical impedance spectroscopy (EIS)-type aptasensors, we integrate the LBL technique with our previously developed "solid-state probe" technique for redox probes immobilization on electrode surfaces to design and fabricate BECI-based differential pulse voltammetry (DPV)-type aptasensors. BFCs can directly harvest energy from ambient biofuels as green energy sources, which could lead to their application as simple, flexible, and portable power sources. Porous materials provide favorable microenvironments for enzyme immobilization, which can enhance BFC power output. Furthermore, by introducing aptamer-based logic systems to BFCs, such systems could be applied as self

  8. The distribution of impurities in the interfaces and window layers of thin-film solar cells

    International Nuclear Information System (INIS)

    We report a systematic multielement study of impurities in CdS window layers by dynamic and quantitative secondary-ion-mass spectrometry (SIMS) with high depth resolution. The study was carried out on CdTe/CdS solar cell structures, with the glass substrate removed. The analysis proceeded from the transparent conductive oxide free surface to the CdTe absorbing layer with a view to examining the influence of the CdCl2 heat treatment on the distribution and concentration of impurities in the structures. Special attention was paid to the impurities present in the CdS window layer that may be electrically active, and therefore affect the characteristics of the CdTe/CdS device. It was shown that Cl, Na, and Sb impurities had higher concentrations in CdS following cadmium chloride (CdCl2) heat treatment while Pb, O, Sn, and Cu conserved the same concentration. Furthermore, Zn, Si, and In showed slightly lower concentrations on CdCl2 treatment. Possible explanations of these changes are discussed and the results compared with previous SIMS measurements from the 'back wall' (i.e., from the CdTe free surface through the glass substrate) obtained from the same structures

  9. Performance improvement of P3HT/TiO2 coaxial heterojunction polymer solar cells by introducing a CdS interface modifier

    International Nuclear Information System (INIS)

    Coaxial heterojunction polymer solar cells consisting of vertical aligned crystalline TiO2 nanotube arrays transferred onto FTO-coated glass and ordered interpenetrating poly(3-hexylthiophene-2,5-diyl) (P3HT) have been fabricated through interface sensitization of CdS quantum dots on TiO2 nanotube walls. The performances of structurally identical polymer solar cells with and without CdS quantum dots sensitization were investigated and compared. The sensitized P3HT/CdS-TiO2 cell demonstrated an open-circuit photovoltage of 0.72 V and a short-circuit current of 8.29 mA/cm2 while the P3HT/TiO2 cell was 0.41 V and 5.64 mA/cm2. The efficiency of this sensitized cell represents a more than four-fold improvement compared to the non-sensitized cell. By probing the charge transport characteristics at interfaces and the mechanism of photoelectric conversion, it is found the moderately interfacial CdS QDs plays the role of assisting charge separation and suppression of back recombination at interfaces, which accounts for the observed enhanced Jsc and Voc in photovoltaic performance. - Graphical abstract: Schematic illustration of the Au/P3HT/CdS-TiO2/FTO coaxial heterojunction polymer solar cell and its photovoltaic property compared with Au/P3HT/TiO2/FTO cell. Highlights: ► CdS QDs sensitized P3HT/TiO2 solid coaxial heterojunction solar cells are fabricated. ► The Voc of such sensitized polymer solar cell reaches the value as high as 0.72 V. ► 4.5 times higher PCE obtains as compared with the non-sensitized cell. ► The dominate roles of CdS QDs sensitization on the PCE enhancement are investigated.

  10. Interface modification effect between p-type a-SiC:H and ZnO:Al in p-i-n amorphous silicon solar cells

    OpenAIRE

    Baek, Seungsin; Lee, Jeong Chul; Lee, Youn-Jung; Iftiquar, Sk Md; Kim, Youngkuk; Park, Jinjoo; Yi, Junsin

    2012-01-01

    Aluminum-doped zinc oxide (ZnO:Al) [AZO] is a good candidate to be used as a transparent conducting oxide [TCO]. For solar cells having a hydrogenated amorphous silicon carbide [a-SiC:H] or hydrogenated amorphous silicon [a-Si:H] window layer, the use of the AZO as TCO results in a deterioration of fill factor [FF], so fluorine-doped tin oxide (Sn02:F) [FTO] is usually preferred as a TCO. In this study, interface engineering is carried out at the AZO and p-type a-SiC:H interface to obtain a b...

  11. Interface stability in solid oxide fuel cells for intermediate temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Solak, N.

    2007-06-15

    This thesis aims to determine the phase equilibria and the thermodynamics of the relevant phases in the systems La-Sr-Ga-Mg-Ni-O, Ce-Gd-Sr-Ni-O, and Ce-Gd-La-Ni-O. Subsystems of these multi-component systems were thermodynamically modeled, based on the available literature and experimental data obtained from this work. The experimental and computational results were used to predict the compatibility/reactivity of IT-SOFC components under fabrication and/or operation conditions. Various experimental techniques were employed for determination of the phase equilibria such as Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX), X-ray Diffraction (XRD), Differential Scanning and Adiabatic Calorimetry, and Mass Spectrometry (MS). The CALPHAD-method (CALculation of PHAse Diagrams) and THERMOCALC software were used to obtain self-consistent sets of Gibbs energy functions. The following systems were investigated experimentally: La-Ni-O, La-Ga-Ni-O, La-Sr-Ni-O, La-Mg-Ni-O, La-Ga-Mg-Ni-O, La-Sr-Ga-Ni-O, La-Sr-Ga-Mg-Ni-O, Ce-Ni-O, Ce-Sr-O, Gd-Ni-O, Gd-Sr-O, Ce-Gd-Ni-O, Ce-Gd-Sr-O, Ce-Sr-Ni-O, Gd-Sr-Ni-O, Ce-Gd-Sr-Ni-O and Ce-Gd-La-Ni-O. Using results from this experimental work and data from the literature, the following systems were thermodynamically modeled: La-Ni-O, La-Ga-Ni-O, La-Sr-Ni-O, La-Mg-Ni-O, Ce-Ni-O, Ce-Sr-O, Gd-Ni-O and Gd-Sr-O. It could be concluded that doped ceria-based materials are chemically compatible with NiO during conditions typical for both the fabrication and the operation of IT-SOFC's, whereas LSGM-type electrolytes react with NiO under the fuel cell fabrication conditions. Moreover, although La{sub 2}NiO{sub 4} is a high-performance cathode, it cannot be used in combination with LSGM- or CGO-type electrolytes, due to its reactivity with both of these materials under fabrication conditions. (orig.)

  12. Special Morphological Features at the Interface of the Renal Stem/Progenitor Cell Niche Force to Reinvestigate Transport of Morphogens During Nephron Induction.

    Science.gov (United States)

    Minuth, Will W; Denk, Lucia

    2016-01-01

    Formation of a nephron depends on reciprocal signaling of different morphogens between epithelial and mesenchymal cells within the renal stem/progenitor cell niche. Previously, it has been surmised that a close proximity exists between both involved cell types and that morphogens are transported between them by diffusion. However, actual morphological data illustrate that mesenchymal and epithelial stem/progenitor cell bodies are separated by a striking interface. Special fixation of specimens by glutaraldehyde (GA) solution including cupromeronic blue, ruthenium red, or tannic acid for electron microscopy depicts that the interface is not void but filled in extended areas by textured extracellular matrix. Surprisingly, projections of mesenchymal cells cross the interface to contact epithelial cells. At those sites the plasma membranes of a mesenchymal and an epithelial cell are connected via tunneling nanotubes. Regarding detected morphological features in combination with involved morphogens, their transport cannot longer be explained solely by diffusion. Instead, it has to be sorted according to biophysical properties of morphogens and to detected environment. Thus, the new working hypothesis is that morphogens with good solubility such as glial cell line-derived neurotrophic factor (GDNF) or fibroblast growth factors (FGFs) are transported by diffusion. Morphogens with minor solubility such as bone morphogenetic proteins (BMPs) are secreted and stored for delivery on demand in illustrated extracellular matrix. In contrast, morphogens with poor solubility such as Wnts are transported in mesenchymal cell projections along the plasma membrane or via illustrated tunneling nanotubes. However, the presence of an intercellular route between mesenchymal and epithelial stem/progenitor cells by tunneling nanotubes also makes it possible that all morphogens are transported this way. PMID:26862472

  13. Efficiency Enhancement in Organic Solar Cells by Incorporating Silica-coated Gold Nanorods at the Buffer/Active interface

    CERN Document Server

    Zhao, Haoyang; Tong, Peiqian; Cui, Yanxia; Hao, Yuying; Sun, Qinjun; Shi, Fang; Zhan, Qiuqiang; Wang, Hua; Zhu, Furong

    2015-01-01

    The performance of organic solar cells (OSCs) can be greatly improved by incorporating silica-coated gold nanorods (Au@SiO2 NRs) at the interface between the hole transporting layer and the active layer due to the plasmonic effect. The silica shell impedes the aggregation effect of the Au NRs in ethanol solution as well as the server charge recombination on the surface of the Au NRs otherwise they would bring forward serious reduction in open circuit voltage when incorporating the Au NRs at the positions in contact with the active materials. As a result, while the high open circuit voltage being maintained, the optimized plasmonic OSCs possess an increased short circuit current, and correspondingly an elevated power conversion efficiency with the enhancement factor of ~11%. The origin of performance improvement in OSCs with the Au@SiO2 NRs was analyzed systematically using morphological, electrical, optical characterizations along with theoretical simulation. It is found that the broadband enhancement in abso...

  14. Measurement of capillary pressure in fuel cell diffusion media, micro-porous layers, catalyst layers, and interfaces

    Science.gov (United States)

    LaManna, Jacob M.; Bothe, James V.; Zhang, Feng Yuan; Mench, Matthew M.

    2014-12-01

    In this work, semi-empirical Leverett J-Function relationships relating capillary pressure and water saturation are experimentally derived for commercial and experimental polymer electrolyte fuel cell materials developed for automotive applications. Relationships were derived for Mitsubishi Rayon Corp. (MRC) U105 and General Motors (GM) experimental high tortuosity diffusion media (DM), the micro-porous layer (MPL), and the catalyst layer (CL). The standard Leverett J-Function under-predicted drainage curves for the DM at high saturation levels and significantly under-predicted the capillary pressure requirements for the MPL and CL across the entire saturation range. Composite structures were tested to understand interfacial effects for DM|MPL and MPL|CL. Each additional layer was found to superimpose its effects on capillary pressure onto the previous layers. The MPL formulation tested increased in porosity from a 136 nm peak average to a 153 nm peak average with increased surface porosity of the substrate. Additionally, small voids and pockets that accumulate liquid water were found to exist in the MPL|CL interface. The results of this work are useful for computational modelers seeking to enhance the resolution of their macroscopic multi-phase flow models which underestimate capillary pressure using the standard Leverett J-Function.

  15. Interface-engineering additives of poly(oxyethylene tridecyl ether) for low-band gap polymer solar cells consisting of PCDTBT:PCBM₇₀ bulk-heterojunction layers.

    Science.gov (United States)

    Huh, Yoon Ho; Park, Byoungchoo

    2013-01-14

    We herein report on the improved photovoltaic (PV) effects of using a polymer bulk-heterojunction (BHJ) layer that consists of a low-band gap electron donor polymer of poly(N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)) (PCDTBT) and an acceptor of [6,6]-phenyl C₇₁ butyric acid methyl ester (PCBM₇₀), doped with an interface-engineering surfactant additive of poly(oxyethylene tridecyl ether) (PTE). The presence of an interface-engineering additive in the PV layer results in excellent performance; the addition of PTE to a PCDTBT:PCBM₇₀ system produces a power conversion efficiency (PCE) of 6.0%, which is much higher than that of a reference device without the additive (4.9%). We attribute this improvement to an increased charge carrier lifetime, which is likely to be the result of the presence of PTE molecules oriented at the interfaces between the BHJ PV layer and the anode and cathode, as well as at the interfaces between the phase-separated BHJ domains. Our results suggest that the incorporation of the PTE interface-engineering additive in the PCDTBT:PCBM₇₀ PV layer results in a functional composite system that shows considerable promise for use in efficient polymer BHJ PV cells. PMID:23389265

  16. Interface modification effect between p-type a-SiC:H and ZnO:Al in p-i-n amorphous silicon solar cells.

    Science.gov (United States)

    Baek, Seungsin; Lee, Jeong Chul; Lee, Youn-Jung; Iftiquar, Sk Md; Kim, Youngkuk; Park, Jinjoo; Yi, Junsin

    2012-01-01

    Aluminum-doped zinc oxide (ZnO:Al) [AZO] is a good candidate to be used as a transparent conducting oxide [TCO]. For solar cells having a hydrogenated amorphous silicon carbide [a-SiC:H] or hydrogenated amorphous silicon [a-Si:H] window layer, the use of the AZO as TCO results in a deterioration of fill factor [FF], so fluorine-doped tin oxide (Sn02:F) [FTO] is usually preferred as a TCO. In this study, interface engineering is carried out at the AZO and p-type a-SiC:H interface to obtain a better solar cell performance without loss in the FF. The abrupt potential barrier at the interface of AZO and p-type a-SiC:H is made gradual by inserting a buffer layer. A few-nanometer-thick nanocrystalline silicon buffer layer between the AZO and a-SiC:H enhances the FF from 67% to 73% and the efficiency from 7.30% to 8.18%. Further improvements in the solar cell performance are expected through optimization of cell structures and doping levels. PMID:22257671

  17. Study of the interface behaviour of SiC/Si/sub 3/N/sub 4/ composites using a 3-D unit cell model

    International Nuclear Information System (INIS)

    A 3-D unit cell model has been developed to investigate the interface failure behavior of SiC/sub f//Si/sub 3/N/sub 4/ composites under tensile loading at room and elevated temperatures. The model idealizes the composite as a regular rectangular array of fibers embedded in matrix, and it introduces 3-D contact elements between the fiber and the matrix to simulate the interface conditions. Slippage between 0 and 90 degree layers are also considered by introducing another set of contact elements at the layer separation planes. Two interface conditions, namely, infinitely strong and weakly bonded are considered to establish the correlation with the experimental data. To simulate the weak interface, the fiber and matrix are assumed to side over one another with shear stress through Coulomb mechanism. Same assumption has also been adopted for the layer separation planes. A finite element program utilizing these concepts has been developed. Stress strain behavior and the local stress distributions at various temperatures within the unit cell are presented. The investigation has also been conducted with the consideration of residual stress that are invariably developed in composite materials during the curing process because of the thermal expansion mismatch of the fibers and the matrix. (author) 16 figs.; 10 refs

  18. Stability of templated and nanoparticles dye-sensitized solar cells: photovoltaic and electrochemical investigation of degradation mechanisms at the photoelectrode interface

    International Nuclear Information System (INIS)

    Graphical abstract: Highly porous templated TiO2 films are promising alternative to nanoparticle layers for dye-sensitized solar cell applications. However, the increase of the electron transfer surface could promote detrimental side reactions and accelerate cell degradation upon ageing. Therefore, stability of templated cells under UV exposure, visible light soaking and thermal stress was studied in comparison to nanoparticle cells. -- Highlights: •Stability of templated and nanoparticle dye-sensitized solar cells is compared. •Templated cells are more sensitive to UV degradation than nanoparticle cells. •Templated cells are as stable as nanoparticle cells under light soaking. •Templated cells are more stable than nanoparticle cells under thermal stress. •Templated cells present better overall performances than nanoparticle cells. -- Abstract: A key issue in the commercialization of dye-sensitized solar cells is to maintain high efficiency and long lifetime. As reported in the literature, dye-sensitized solar cells are stable under visible light soaking but thermal stress and UV exposure lead to efficiency degradation. However, all the stability studies published so far have been performed on cells whose TiO2 electrodes were prepared by tape casting or screen printing of nanoparticle pastes/inks. The present study concerns cells based on highly porous templated TiO2 electrodes, whose larger surface area could enhance the negative effects of thermal stress, light soaking and UV exposure. The long-term stability of these cells is compared with a classical nanoparticle-based cell using current-voltage measurements (I-V curves) and electrochemical impedance spectroscopy. Due to their higher active interface, templated cells are more sensitive than nanoparticle cells to UV illumination, although this can be easily solved in both cases by the use of a UV filter. The templated cells are as stable as the nanoparticle cells under visible light soaking (UV

  19. Electrodes/electrolyte interfaces in the presence of a surface-modified photopolymer electrolyte: application in dye-sensitized solar cells.

    Science.gov (United States)

    Sacco, Adriano; Bella, Federico; De La Pierre, Stefano; Castellino, Micaela; Bianco, Stefano; Bongiovanni, Roberta; Pirri, Candido Fabrizio

    2015-04-01

    Since hundreds of studies on photoanodes and cathodes show that the electrode/electrolyte interfaces represent a key aspect at the base of dye-sensitized solar cell (DSSC) performances, it is reported here that these interfaces can be managed by a smart design of the spatial composition of quasi-solid electrolytes. By means of a cheap, rapid, and green process of photoinduced polymerization, composition-tailored polymer electrolyte membranes (PEMs) with siloxane-enriched surfaces are prepared, and their properties are thoroughly described. When assembled in DSSCs, the interfacial action promoted by the composition-tailored PEMs enhances the photocurrent and fill factor values, thus increasing the global photovoltaic conversion efficiency with respect to the non-modified PEMs. Moreover, the presence of the siloxane-chain-enriched surface increases the hydrophobicity and reduces the water vapor permeation into the device, thus enhancing the cell's durability. PMID:25677499

  20. Research on the boron contamination at the p/i interface of microcrystalline silicon solar cells deposited in a single PECVD chamber

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiao-Dan; Sun Fu-He; Wei Chang-Chun; Sun Jian; Zhang De-Kun; Geng Xin-Hua; Xiong Shao-Zhen; Zhao Ying

    2009-01-01

    This paper studies boron contamination at the interface between the p and i layers of μc-Si:H solar cells deposited in a single-chamber PECVD system. The boron depth profile in the i layer was measured by Secondary Ion Mass Spectroscopy. It is found that the mixed-phase μc-Si:H materials with 40% crystalline volume fraction is easy to be affected by the residual boron in the reactor. The experimental results showed that a 500-nm thick μc-Si:H covering layer or a 30-seconds of hydrogen plasma treatment can effectively reduce the boron contamination at the p/i interface. However, from viewpoint of cost reduction, the hydrogen plasma treatment is desirable for solar cell manufacture because the substrate is not moved during the hydrogen plasma treatment.

  1. Interface and charge transport studies in organic solar cells based on P3HT:PCBM bulk heterojunctions

    Science.gov (United States)

    Rujisamphan, Nopporn

    Interfaces and charge transport in organic solar cells based on P3HT:PCBM bulk heterojunctions (BHJ) were studied. State-of-the-art TEM sample preparation techniques, including in-situ lift-out, were used with a dual focused ion beam (FIB) system on a typical device (ITO/PEDOT:PSS/P3HT:PCBM/Al). Through bright field (BF) TEM micrographs a mixed layer between the Al electrode and the organic active layer (P3HT:PCBM) was clearly observed in both as-fabricated and annealed devices. The effect of Al contact resistance before and after annealing was studied using the vertical transmission line model (TLM). It was found that by annealing after Al evaporation, the contact resistivity decreased by 38%. Energy filtered transmission electron microscopy (EFTEM) clearly revealed a nanoscopic phase separation. From the EFTEM images, the average length and the diameter of P3HT fibrils were found to be approximately 70 nm and 15 nm, respectively. Combining the EFTEM, selected area electron diffraction (SAED) patterns and X-ray diffraction (XRD) results, the number and spacing of the ordered polymer chains in P3HT fibrils were calculated. There were about 18 repeating units of P3HT perpendicular to the fibril, about 184 layers of pi-pi* stacking along the fibril and about 9 layers of interchain stacking within the fibril. Accompanied by cross-section samples prepared by the FIB technique, the vertical morphology of each phase was analyzed. By collecting 30 eV energy loss images, the phase separation in the blend of P3HT:PCBM was distinguishable. A higher P3HT concentration was observed at the top of the cell. The temperature dependent charge separation and charge transport were studied using modulated surface photovoltage spectroscopy (SPV) on layers of P3HT, PCBM, and the blend. The unchanged character of the SPV spectra on the P3HT provides evidence that the mechanisms of charge separation, recombination and charge transport does not change qualitatively after cooling. It was

  2. Development of tissue engineered strategies combining stem cells and scaffolds aimed to regenerate bone and osteochondral interfaces

    OpenAIRE

    Márcia T Rodrigues

    2011-01-01

    Bone is a specialized tissue characterized by its rigidity and hardness, yet light weighed to fulfill diverse functions as mineral storage, organ protection or body support and locomotion. Despite its extraordinary healing ability, bone response may be unsuccessful to repair severe damage caused by injury or degenerative diseases. Furthermore, when bone is affected, other tissues and interfaces might be quite distressed as well. Cartilage and bone interface of the joints (osteo...

  3. Air/Liquid-pressure and heartbeat-driven flexible fiber nanogenerators as a micro/nano-power source or diagnostic sensor.

    Science.gov (United States)

    Li, Zetang; Wang, Zhong Lin

    2011-01-01

    We present a new approach for fabricating flexible fiber nanogenerators (FNGs) that can be used for smart shirts, flexible electronics, and medical applications. These FNGs are based on carbon fibers that are covered cylindrically by textured zinc oxide (ZnO) thin films. Once subjected to uni-compression by applying a pressure, the cylindrical ZnO thin film is under a compressive strain, resulting in a macroscopic piezopotential across its inner and exterior surfaces owing to the textured structure of the film, which is the driving force for generating an electric current in the external load. Using such a structure, an output peak voltage of 3.2 V and average current density of 0.15 μA cm(-2) are demonstrated. The FNGs rely on air pressure, so that it can work in a non-contact mode in cases of rotating tires, flowing air/liquid, and even in blood vessels. Pressure-driven FNGs added to a syringe show potential to harvest energy in blood vessels, gas pipes, and oil pipes, as long as there is a fluctuation in pressure (or turbulence). Heart-pulse driven FNGs can serve as ultrasensitive sensors for monitoring the behavior of the human heart, which may possibly be applied to medical diagnostics as sensors and measurement tools. PMID:21080378

  4. Microprocessor interfacing

    CERN Document Server

    Vears, R E

    2014-01-01

    Microprocessor Interfacing provides the coverage of the Business and Technician Education Council level NIII unit in Microprocessor Interfacing (syllabus U86/335). Composed of seven chapters, the book explains the foundation in microprocessor interfacing techniques in hardware and software that can be used for problem identification and solving. The book focuses on the 6502, Z80, and 6800/02 microprocessor families. The technique starts with signal conditioning, filtering, and cleaning before the signal can be processed. The signal conversion, from analog to digital or vice versa, is expl

  5. Insight into the CH3NH3PbI3/C interface in hole-conductor-free mesoscopic perovskite solar cells.

    Science.gov (United States)

    Li, Jiangwei; Niu, Guangda; Li, Wenzhe; Cao, Kun; Wang, Mingkui; Wang, Liduo

    2016-08-01

    Perovskite solar cells (PSCs) with hole-conductor-free mesoscopic architecture have shown superb stability and great potential in practical application. The printable carbon counter electrodes take full responsibility of extracting holes from the active CH3NH3PbI3 absorbers. However, an in depth study of the CH3NH3PbI3/C interface properties, such as the structural formation process and the effect of interfacial conditions on hole extraction, is still lacking. Herein, we present, for the first time, an insight into the spatial confinement induced CH3NH3PbI3/C interface formation by in situ photoluminescence observations during the crystallization process of CH3NH3PbI3. The derived reaction kinetics allows a quantitative description of the perovskite formation process. In addition, we found that the interfacial contact between carbon and perovskite was dominant for hole extraction efficiency and associated with the photovoltaic parameter of short circuit current density (JSC). Consequently, we conducted a solvent vapor assisted process of PbI2 diffusion to carefully control the CH3NH3PbI3/C interface with less unreacted PbI2 barrier. The improvement of interface conditions thereby contributes to a high hole extraction proved by the charge extraction resistance and PL lifetime change, resulting in the increased JSC valve. PMID:27385565

  6. The silicon/zinc oxide interface in amorphous silicon-based thin-film solar cells: Understanding an empirically optimized contact

    Science.gov (United States)

    Gerlach, D.; Wilks, R. G.; Wippler, D.; Wimmer, M.; Lozac'h, M.; Félix, R.; Mück, A.; Meier, M.; Ueda, S.; Yoshikawa, H.; Gorgoi, M.; Lips, K.; Rech, B.; Sumiya, M.; Hüpkes, J.; Kobayashi, K.; Bär, M.

    2013-07-01

    The electronic structure of the interface between the boron-doped oxygenated amorphous silicon "window layer" (a-SiOx:H(B)) and aluminum-doped zinc oxide (ZnO:Al) was investigated using hard x-ray photoelectron spectroscopy and compared to that of the boron-doped microcrystalline silicon (μc-Si:H(B))/ZnO:Al interface. The corresponding valence band offsets have been determined to be (-2.87 ± 0.27) eV and (-3.37 ± 0.27) eV, respectively. A lower tunnel junction barrier height at the μc-Si:H(B)/ZnO:Al interface compared to that at the a-SiOx:H(B)/ZnO:Al interface is found and linked to the higher device performances in cells where a μc-Si:H(B) buffer between the a-Si:H p-i-n absorber stack and the ZnO:Al contact is employed.

  7. A 3D immersed finite element method with non-homogeneous interface flux jump for applications in particle-in-cell simulations of plasma-lunar surface interactions

    Science.gov (United States)

    Han, Daoru; Wang, Pu; He, Xiaoming; Lin, Tao; Wang, Joseph

    2016-09-01

    Motivated by the need to handle complex boundary conditions efficiently and accurately in particle-in-cell (PIC) simulations, this paper presents a three-dimensional (3D) linear immersed finite element (IFE) method with non-homogeneous flux jump conditions for solving electrostatic field involving complex boundary conditions using structured meshes independent of the interface. This method treats an object boundary as part of the simulation domain and solves the electric field at the boundary as an interface problem. In order to resolve charging on a dielectric surface, a new 3D linear IFE basis function is designed for each interface element to capture the electric field jump on the interface. Numerical experiments are provided to demonstrate the optimal convergence rates in L2 and H1 norms of the IFE solution. This new IFE method is integrated into a PIC method for simulations involving charging of a complex dielectric surface in a plasma. A numerical study of plasma-surface interactions at the lunar terminator is presented to demonstrate the applicability of the new method.

  8. Generation of airway epithelial cells with native characteristics from mouse induced pluripotent stem cells.

    Science.gov (United States)

    Yoshie, Susumu; Imaizumi, Mitsuyoshi; Nakamura, Ryosuke; Otsuki, Koshi; Ikeda, Masakazu; Nomoto, Yukio; Wada, Ikuo; Omori, Koichi

    2016-05-01

    Airway epithelial cells derived from induced pluripotent stem (iPS) cells are expected to be a useful source for the regeneration of airway epithelium. Our preliminary study of embryoid body (EB) formation and the air-liquid interface (ALI) method suggested that mouse iPS cells can differentiate into airway epithelial cells. However, whether the cells generated from mouse iPS cells had the character and phenotype of native airway epithelial cells remained uninvestigated. In this study, we generated airway epithelial cells from EBs by culturing them under serum-free conditions supplemented with Activin and bFGF and by the ALI method and characterized the iPS cell-derived airway epithelial cells in terms of their gene expression, immunoreactivity, morphology, and function. Analysis by quantitative real-time reverse transcription-polymerase chain reaction(RT-PCR) revealed that the expression of the undifferentiated cell marker Nanog decreased time-dependently after the induction of differentiation, whereas definitive endoderm markers Foxa2 and Cxcr4 were transiently up-regulated. Thereafter, the expression of airway epithelium markers such as Tubb4a, Muc5ac, and Krt5 was detected by RT-PCR and immunostaining. The formation of tight junctions was also confirmed by immunostaining and permeability assay. Analysis by hematoxylin and eosin staining and scanning electron microscopy indicated that the cells generated from mouse iPS cells formed airway-epithelium-like tissue and had cilia, the movement of which was visualized and observed to be synchronized. These results demonstrate that the airway epithelial cells generated by our method have native characteristics and open new perspectives for the regeneration of injured airway epithelium. PMID:26590823

  9. Estradiol increases mucus synthesis in bronchial epithelial cells.

    Directory of Open Access Journals (Sweden)

    Anthony Tam

    Full Text Available Airway epithelial mucus hypersecretion and mucus plugging are prominent pathologic features of chronic inflammatory conditions of the airway (e.g. asthma and cystic fibrosis and in most of these conditions, women have worse prognosis compared with male patients. We thus investigated the effects of estradiol on mucus expression in primary normal human bronchial epithelial cells from female donors grown at an air liquid interface (ALI. Treatment with estradiol in physiological ranges for 2 weeks caused a concentration-dependent increase in the number of PAS-positive cells (confirmed to be goblet cells by MUC5AC immunostaining in ALI cultures, and this action was attenuated by estrogen receptor beta (ER-β antagonist. Protein microarray data showed that nuclear factor of activated T-cell (NFAT in the nuclear fraction of NHBE cells was increased with estradiol treatment. Estradiol increased NFATc1 mRNA and protein in ALI cultures. In a human airway epithelial (1HAE0 cell line, NFATc1 was required for the regulation of MUC5AC mRNA and protein. Estradiol also induced post-translational modification of mucins by increasing total fucose residues and fucosyltransferase (FUT-4, -5, -6 mRNA expression. Together, these data indicate a novel mechanism by which estradiol increases mucus synthesis in the human bronchial epithelium.

  10. An in-situ surface electrochemistry approach toward whole-cell studies: Charge transfer between Geobacter sulfurreducens and electrified metal/electrolyte interfaces through linker molecules

    International Nuclear Information System (INIS)

    Electrochemical reactivity and structure properties of electrogenic bacteria, Geobacter sulfurreducens (Gs) were studied to explore the heterogeneous electron transfer at the bacteria/electrode interface using electrochemical and in-situ spectroscopic techniques. The redox behavior of Gs adsorbed on a gold electrode, which is modified with a ω-functionalized self-assembled monolayer (SAM) of alkanethiols, depends strongly on the terminal group. The latter interacts directly with outermost cytochromes embedded into the outer membrane of the Gs cells. The redox potential of bacterial cells bound electrostatically to a carboxyl-terminated SAM is close to that observed for bacteria attached to a bare gold electrode, revealing a high electronic coupling at the cell/SAM interface. The redox potentials of bacterial cells adsorbed on amino- and pyridyl-terminated SAMs are significantly different suggesting that the outermost cytochromes changes their conformation upon adsorption on these SAMs. No redox activity of Gs was found with CH3-, N(CH3)3+- and OH-terminated SAMs. Complementary in-situ spectroscopic studies on bacteria/SAMs/Au electrode assemblies were carried out to monitor structure changes of the bacterial cells upon polarization. Spectro-electrochemical techniques revealed the electrochemical turnover of the oxidized and reduced states of outer membrane cytochromes (OMCs) in Gs, providing evidence that the OMCs are responsible for the direct electron transfer to metal electrodes, such as gold or silver, during the electricity production. Furthermore, we observed spectroscopic signatures of the native structure of the OMCs and no conformational change during the oxidation/reduction process of the microorganisms. These findings indicate that the carboxyl-anchoring group provides biocompatible conditions for the outermost cytochromes of the Gs, which facilitate the heterogeneous electron transfer at the microorganism/electrode interface

  11. Wavelength-resolved simultaneous photoelectrochemical bifunctional sensor on single interface: A newly in vitro approach for multiplexed DNA monitoring in cancer cells.

    Science.gov (United States)

    Zheng, Yingning; Liang, Wenbin; Yuan, Yali; Xiong, Chengyi; Xie, Shunbi; Wang, Haijun; Chai, Yaqin; Yuan, Ruo

    2016-07-15

    Currently, the photoelectrochemical (PEC) strategies can just achieve single analyte detection on a single interface with limited detection efficiency. It is highly valuable but full of challenge to develop a PEC biosensor for multiple analytes evaluation on a single interface. For this point, the wavelength-selective photoactive materials, which could generate separated photocurrents under excitation lights with certain wavelengths, were mainly important to overcome this challenge. Herein, these wavelength-selective photoactive materials were successfully synthesized and served as signal indicators to construct a novel PEC biosensor for multiple analytes evaluation on a single interface for the first time. Moreover, an enzyme-assisted target recycling amplification strategy was introduced for ultrasensitive monitoring. As a result, the proposed PEC biosensor showed excellent analytical performance for both oral cancer (ORVOA 1) gene and p53 gene down to attomolar level. In addition, the fabricated PEC biosensor was employed to evaluate ORVOA 1 gene and p53 gene in Hela cells. This assay has laid the foundation for fabrication of simple, ultrasensitive and economical PEC diagnostic devices to detect multiple analytes in cells, which paved a new avenue for early diagnosis of cancer with higher efficiency and accuracy. PMID:27003607

  12. A study of interfaces between organic and metal materials and their application in polymer light-emitting diodes and polymer photovoltaic solar cells

    Science.gov (United States)

    Li, Juo-Hao

    2009-12-01

    In the past few decades, it attracts a lot of attention for the researches of organic semiconductor due to its new and interesting properties, compared with conventional soft material and inorganic semiconductor. Several kinds of electronic devices such as light emitting diodes, thin film transistors and photovoltaic solar cell based on these organic semiconductors are also proposed and studied. This dissertation will focus on interface between organic and metal, which is one of the mysteries and critical issues remaining in the material properties and limiting the device performance. In the first chapter, a brief review and introduction of the organic semiconductor and organic electronics will be described. The purpose is to introduce the research background, motivation and methodology. Chapter two demonstrates the concept of top-emitting light-emitting diodes and the research focus on the interfaces between the light-emitting polymer and electrodes. An interfacial layer is introduced to improve the hole-injection from the anode. Except for alternating the electrode architecture, surface treatment or modification also have significant influences on interfacial electronic structure. Chapter three describes the discovery of solvent treatment on top of the light-emitting polymer and its application on organic electrophosphorescent devices. To further study the interfaces in organic electronics, an interface layer of sol-gel processed titanium oxide is introduced into organic electronic devices. Chapter four describes the amorphous titanium oxide and its application on polymer light-emitting diodes, while Chapter five demonstrates nanocrystalline titanium dioxide and its application in both light-emitting devices and polymer photovoltaic solar cells.

  13. Transport, Interfaces, and Modeling in Amorphous Silicon Based Solar Cells: Final Technical Report, 11 February 2002 - 30 September 2006

    Energy Technology Data Exchange (ETDEWEB)

    Schiff, E. A.

    2008-10-01

    Results for a-Si characteristics/modeling; photocarrier drift mobilities in a-Si;H, ..mu..c-Si:H, CIGS; hole-conducting polymers as p-layer for a-Si and c-Si; IR spectra of p/i and n/i interfaces in a-Si.

  14. Interface superconductivity

    International Nuclear Information System (INIS)

    Highlights: • We discuss interfacial superconductivity, a field boosted by the discovery of the superconducting interface between LaAlO. • This system allows the electric field control and the on/off switching of the superconducting state. • We compare superconductivity at the interface and in bulk doped SrTiO. • We discuss the role of the interfacially induced Rashba type spin–orbit. • We briefly discuss superconductivity in cuprates, in electrical double layer transistor field effect experiments. • Recent observations of a high Tc in a monolayer of FeSe deposited on SrTiO3 are presented. - Abstract: Low dimensional superconducting systems have been the subject of numerous studies for many years. In this article, we focus our attention on interfacial superconductivity, a field that has been boosted by the discovery of superconductivity at the interface between the two band insulators LaAlO3 and SrTiO3. We explore the properties of this amazing system that allows the electric field control and on/off switching of superconductivity. We discuss the similarities and differences between bulk doped SrTiO3 and the interface system and the possible role of the interfacially induced Rashba type spin–orbit. We also, more briefly, discuss interface superconductivity in cuprates, in electrical double layer transistor field effect experiments, and the recent observation of a high Tc in a monolayer of FeSe deposited on SrTiO3

  15. Upregulation of RNA Processing Factors in Poorly Differentiated Lung Cancer Cells

    Directory of Open Access Journals (Sweden)

    Kenneth G. Geles

    2016-04-01

    Full Text Available Intratumoral heterogeneity in non–small cell lung cancer (NSCLC has been appreciated at the histological and cellular levels, but the association of less differentiated pathology with poor clinical outcome is not understood at the molecular level. Gene expression profiling of intact human tumors fails to reveal the molecular nature of functionally distinct epithelial cell subpopulations, in particular the tumor cells that fuel tumor growth, metastasis, and disease relapse. We generated primary serum-free cultures of NSCLC and then exposed them to conditions known to promote differentiation: the air-liquid interface (ALI and serum. The transcriptional network of the primary cultures was associated with stem cells, indicating a poorly differentiated state, and worse overall survival of NSCLC patients. Strikingly, the overexpression of RNA splicing and processing factors was a prominent feature of the poorly differentiated cells and was also observed in clinical datasets. A genome-wide analysis of splice isoform expression revealed many alternative splicing events that were specific to the differentiation state of the cells, including an unexpectedly high frequency of events on chromosome 19. The poorly differentiated cells exhibited alternative splicing in many genes associated with tumor progression, as exemplified by the preferential expression of the short isoform of telomeric repeat-binding factor 1 (TERF1, also known as Pin2. Our findings demonstrate the utility of the ALI method for probing the molecular mechanisms that underlie NSCLC pathogenesis and provide novel insight into posttranscriptional mechanisms in poorly differentiated lung cancer cells.

  16. Designing Interfaces

    CERN Document Server

    Tidwell, Jenifer

    2010-01-01

    Despite all of the UI toolkits available today, it's still not easy to design good application interfaces. This bestselling book is one of the few reliable sources to help you navigate through the maze of design options. By capturing UI best practices and reusable ideas as design patterns, Designing Interfaces provides solutions to common design problems that you can tailor to the situation at hand. This updated edition includes patterns for mobile apps and social media, as well as web applications and desktop software. Each pattern contains full-color examples and practical design advice th

  17. Exploiting the MDM2-CK1α protein-protein interface to develop novel biologics that induce UBL-kinase-modification and inhibit cell growth.

    Directory of Open Access Journals (Sweden)

    Anne-Sophie Huart

    Full Text Available Protein-protein interactions forming dominant signalling events are providing ever-growing platforms for the development of novel Biologic tools for controlling cell growth. Casein Kinase 1 α (CK1α forms a genetic and physical interaction with the murine double minute chromosome 2 (MDM2 oncoprotein resulting in degradation of the p53 tumour suppressor. Pharmacological inhibition of CK1 increases p53 protein level and induces cell death, whilst small interfering RNA-mediated depletion of CK1α stabilizes p53 and induces growth arrest. We mapped the dominant protein-protein interface that stabilizes the MDM2 and CK1α complex in order to determine whether a peptide derived from the core CK1α-MDM2 interface form novel Biologics that can be used to probe the contribution of the CK1-MDM2 protein-protein interaction to p53 activation and cell viability. Overlapping peptides derived from CK1α were screened for dominant MDM2 binding sites using (i ELISA with recombinant MDM2; (ii cell lysate pull-down towards endogenous MDM2; (iii MDM2-CK1α complex-based competition ELISA; and (iv MDM2-mediated ubiquitination. One dominant peptide, peptide 35 was bioactive in all four assays and its transfection induced cell death/growth arrest in a p53-independent manner. Ectopic expression of flag-tagged peptide 35 induced a novel ubiquitin and NEDD8 modification of CK1α, providing one of the first examples whereby NEDDylation of a protein kinase can be induced. These data identify an MDM2 binding motif in CK1α which when isolated as a small peptide can (i function as a dominant negative inhibitor of the CK1α-MDM2 interface, (ii be used as a tool to study NEDDylation of CK1α, and (iii reduce cell growth. Further, this approach provides a technological blueprint, complementing siRNA and chemical biology approaches, by exploiting protein-protein interactions in order to develop Biologics to manipulate novel types of signalling pathways such as cross

  18. Interface Study of ITO/ZnO and ITO/SnO2 Complex Transparent Conductive Layers and Their Effect on CdTe Solar Cells

    Directory of Open Access Journals (Sweden)

    Tingliang Liu

    2013-01-01

    Full Text Available Transparent ITO/ZnO and ITO/SnO2 complex conductive layers were prepared by DC- and RF-magnetron sputtering. Their structure and optical and electronic performances were studied by XRD, UV/Vis Spectroscopy, and four-probe technology. The interface characteristic and band offset of the ITO/ZnO, ITO/SnO2, and ITO/CdS were investigated by Ultraviolet Photoelectron Spectroscopy (UPS and X-ray Photoelectron Spectroscopy (XPS, and the energy band diagrams have also been determined. The results show that ITO/ZnO and ITO/SnO2 films have good optical and electrical properties. The energy barrier those at the interface of ITO/ZnO and ITO/SnO2 layers are almost 0.4 and 0.44 eV, which are lower than in ITO/CdS heterojunctions (0.9 eV, which is beneficial for the transfer and collection of electrons in CdTe solar cells and reduces the minority carrier recombination at the interface, compared to CdS/ITO. The effects of their use in CdTe solar cells were studied by AMPS-1D software simulation using experiment values obtained from ZnO, ITO, and SnO2. From the simulation, we confirmed the increase of Eff, FF, Voc, and Isc by the introduction of ITO/ZnO and ITO/SnO2 layers in CdTe solar cells.

  19. Fast Crystallization and improved Stability of Perovskite Solar Cells with Zn 2 SnO 4 Electron Transporting Layer: Interface Matters

    KAUST Repository

    Bera, Ashok

    2015-12-03

    Here we report that mesoporous ternary oxide Zn2SnO4 can significantly promotes the crystallization of hybrid perovskite layers and serves as an efficient electron transporting material in perovskite solar cells. Such devices exhibit an energy conversion efficiency of 13.34%, which is even higher than that achieved with the commonly used TiO2 in the similar experimental conditions (9.1%). Simple one-step spin coating of CH3NH3PbI3−xClx on Zn2SnO4 is found to lead to rapidly crystalized bilayer perovskite structure without any solvent engineering. Furthermore, ultrafast transient absorption measurement reveals efficient charge transfer at the Zn2SnO4/perovskite interface. Most importantly, solar cells with Zn2SnO4 as the electron-transporting material exhibit negligible electrical hysteresis and exceptionally high stability without encapsulation for over one month. Besides underscoring Zn2SnO4 as a highly promising electron transporting material for perovskite solar cells, our results demonstrate the significant role of interfaces on improving the perovskite crystallization and photovoltaic performance.

  20. Optimization of operating parameters to maximize the current density without flooding at the cathode membrane interface of a PEM fuel cell using Taguchi method and genetic algorithm

    Directory of Open Access Journals (Sweden)

    S.S.L. Rao, A. Shaija, S. Jayaraj

    2014-01-01

    Full Text Available A mathematical model was developed to investigate water accumulation at the cathode membrane interface by varying different operating parameters like fuel cell operating temperature and pressure, cathode and anode humidification temperatures and cathode stoichiometry. Taguchi optimization methodology is then combined with this model to determine the optimal combination of the operating parameters to maximize current density without flooding. Results of analysis of variance (ANOVA show that fuel cell operating temperature and cathode humidification temperature are the two most significant parameters in the ratio of 56.07% and 27.89% respectively and also that higher fuel cell temperature and lower cathode humidification temperature are favourable to get the maximum current draw without flooding at the cathode membrane interface. The global optimum value of the operating parameters to maximize the current density without flooding was obtained by formulating as an optimization problem using genetic algorithm (GA. These results were compared with the results obtained using Taguchi method and it was found to be similar and slightly better.

  1. Reduced interface recombination in Cu2ZnSnS4 solar cells with atomic layer deposition Zn1-xSnxO buffer layers

    OpenAIRE

    Platzer-Björkman, Charlotte; Frisk, Christoper; Larsen, Jes; Ericson, Tove; Li, Shuyi; Scragg, Jonathan; Keller, Jan; Larsson, Fredrik; Törndahl, Tobias

    2015-01-01

    Cu2ZnSnS4 (CZTS) solar cells typically include a CdS buffer layer in between the CZTS and ZnO front contact. For sulfide CZTS, with a bandgap around 1.5 eV, the band alignment between CZTS and CdS is not ideal ("cliff-like"), which enhances interface recombination. In this work, we show how a Zn1-xSnxOy (ZTO) buffer layer can replace CdS, resulting in improved open circuit voltages (V-oc) for CZTS devices. The ZTO is deposited by atomic layer deposition (ALD), with a process previously develo...

  2. Characterization of side population cells from human airway epithelium.

    Science.gov (United States)

    Hackett, Tillie-Louise; Shaheen, Furquan; Johnson, Andrew; Wadsworth, Samuel; Pechkovsky, Dmitri V; Jacoby, David B; Kicic, Anthony; Stick, Stephen M; Knight, Darryl A

    2008-10-01

    The airway epithelium is the first line of contact with the inhaled external environment and is continuously exposed to and injured by pollutants, allergens, and viruses. However, little is known about epithelial repair and in particular the identity and role of tissue resident stem/progenitor cells that may contribute to epithelial regeneration. The aims of the present study were to identify, isolate, and characterize side population (SP) cells in human tracheobronchial epithelium. Epithelial cells were obtained from seven nontransplantable healthy lungs and four asthmatic lungs by pronase digestion. SP cells were identified by verapamil-sensitive efflux of the DNA-binding dye Hoechst 33342. Using flow cytometry, CD45(-) SP, CD45(+) SP, and non-SP cells were isolated and sorted. CD45(-) SP cells made up 0.12% +/- 0.01% of the total epithelial cell population in normal airway but 4.1% +/- 0.06% of the epithelium in asthmatic airways. All CD45(-) SP cells showed positive staining for epithelial-specific markers cytokeratin-5, E-cadherin, ZO-1, and p63. CD45(-) SP cells exhibited stable telomere length and increased colony-forming and proliferative potential, undergoing population expansion for at least 16 consecutive passages. In contrast with non-SP cells, fewer than 100 CD45(-) SP cells were able to generate a multilayered and differentiated epithelium in air-liquid interface culture. SP cells are present in human tracheobronchial epithelium, exhibit both short- and long-term proliferative potential, and are capable of generation of differentiated epithelium in vitro. The number of SP cells is significantly greater in asthmatic airways, providing evidence of dysregulated resident SP cells in the asthmatic epithelium. Disclosure of potential conflicts of interest is found at the end of this article. PMID:18653771

  3. Insight into the CH3NH3PbI3/C interface in hole-conductor-free mesoscopic perovskite solar cells

    Science.gov (United States)

    Li, Jiangwei; Niu, Guangda; Li, Wenzhe; Cao, Kun; Wang, Mingkui; Wang, Liduo

    2016-07-01

    Perovskite solar cells (PSCs) with hole-conductor-free mesoscopic architecture have shown superb stability and great potential in practical application. The printable carbon counter electrodes take full responsibility of extracting holes from the active CH3NH3PbI3 absorbers. However, an in depth study of the CH3NH3PbI3/C interface properties, such as the structural formation process and the effect of interfacial conditions on hole extraction, is still lacking. Herein, we present, for the first time, an insight into the spatial confinement induced CH3NH3PbI3/C interface formation by in situ photoluminescence observations during the crystallization process of CH3NH3PbI3. The derived reaction kinetics allows a quantitative description of the perovskite formation process. In addition, we found that the interfacial contact between carbon and perovskite was dominant for hole extraction efficiency and associated with the photovoltaic parameter of short circuit current density (JSC). Consequently, we conducted a solvent vapor assisted process of PbI2 diffusion to carefully control the CH3NH3PbI3/C interface with less unreacted PbI2 barrier. The improvement of interface conditions thereby contributes to a high hole extraction proved by the charge extraction resistance and PL lifetime change, resulting in the increased JSC valve.Perovskite solar cells (PSCs) with hole-conductor-free mesoscopic architecture have shown superb stability and great potential in practical application. The printable carbon counter electrodes take full responsibility of extracting holes from the active CH3NH3PbI3 absorbers. However, an in depth study of the CH3NH3PbI3/C interface properties, such as the structural formation process and the effect of interfacial conditions on hole extraction, is still lacking. Herein, we present, for the first time, an insight into the spatial confinement induced CH3NH3PbI3/C interface formation by in situ photoluminescence observations during the crystallization

  4. Interface superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gariglio, S., E-mail: stefano.gariglio@unige.ch [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland); Gabay, M. [Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud 11, Centre d’Orsay, 91405 Orsay Cedex (France); Mannhart, J. [Max Planck Institute for Solid State Research, 70569 Stuttgart (Germany); Triscone, J.-M. [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland)

    2015-07-15

    Highlights: • We discuss interfacial superconductivity, a field boosted by the discovery of the superconducting interface between LaAlO. • This system allows the electric field control and the on/off switching of the superconducting state. • We compare superconductivity at the interface and in bulk doped SrTiO. • We discuss the role of the interfacially induced Rashba type spin–orbit. • We briefly discuss superconductivity in cuprates, in electrical double layer transistor field effect experiments. • Recent observations of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3} are presented. - Abstract: Low dimensional superconducting systems have been the subject of numerous studies for many years. In this article, we focus our attention on interfacial superconductivity, a field that has been boosted by the discovery of superconductivity at the interface between the two band insulators LaAlO{sub 3} and SrTiO{sub 3}. We explore the properties of this amazing system that allows the electric field control and on/off switching of superconductivity. We discuss the similarities and differences between bulk doped SrTiO{sub 3} and the interface system and the possible role of the interfacially induced Rashba type spin–orbit. We also, more briefly, discuss interface superconductivity in cuprates, in electrical double layer transistor field effect experiments, and the recent observation of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3}.

  5. The Secretome of Human Bronchial Epithelial Cells Exposed to Fine Atmospheric Particles Induces Fibroblast Proliferation

    Directory of Open Access Journals (Sweden)

    Laurent Martinon

    2013-08-01

    Full Text Available Chronic exposure to particulate pollution is suspected to exacerbate inflammatory respiratory diseases such as asthma characterized by an airway remodelling involving fibrosis. Our study aims to investigate whether the secretome from human bronchial epithelial (HBE cells exposed to fine particulate matter (PM induces fibroblast proliferation. Primary HBE cells grown on air liquid interface were repeatedly exposed to fine PM at 5 and 10 µg/cm² (four treatments, 48 hours apart and maintained in culture for five weeks. Collected basolateral culture medium was used as a conditioned medium for the subsequent treatment of fibroblasts. We observed that the conditioned medium collected from HBE cells treated with fine PM increased the growth rate of fibroblasts compared to the conditioned medium collected from control HBE cells. Fibroblast phenotype assessed by the observation of the vimentin network was well preserved. The mitogenic effect of conditioned medium was reduced in the presence of anti-epidermal growth factor receptor (EGFR, anti-amphiregulin or anti-TGFa, underlining the role of EGFR ligands in fibroblast proliferation. When fibroblasts were co-cultured with HBE cells treated once with fine PM, they exhibited a higher growth rate than fibroblasts co-cultured with non-treated HBE cells. Altogether these data show that the exposure of HBE cells to fine PM induced the production of EGFR ligands in sufficient amount to stimulate fibroblast proliferation providing insight into the role of PM in airway remodelling.

  6. Cells and Culture Systems Used to Model the Small Airway Epithelium.

    Science.gov (United States)

    Bhowmick, Rudra; Gappa-Fahlenkamp, Heather

    2016-06-01

    The pulmonary epithelium is divided into upper, lower, and alveolar (or small) airway epithelia and acts as the mechanical and immunological barrier between the external environment and the underlying submucosa. Of these, the small airway epithelium is the principal area of gas exchange and has high immunological activity, making it a major area of cell biology, immunology, and pharmaceutical research. As animal models do not faithfully represent the human pulmonary system and ex vivo human lung samples have reliability and availability issues, cell lines, and primary cells are widely used as small airway epithelial models. In vitro, these cells are mostly cultured as monolayers (2-dimensional cultures), either media submerged or at air-liquid interface. However, these 2-dimensional cultures lack a three dimension-a scaffolding extracellular matrix, which establishes the intercellular network in the in vivo airway epithelium. Therefore, 3-dimensional cell culture is currently a major area of development, where cells are cultured in a matrix or are cultured in a manner that they develop ECM-like scaffolds between them, thus mimicking the in vivo phenotype more faithfully. This review focuses on the commonly used small airway epithelial cells, their 2-dimensional and 3-dimensional culture techniques, and their comparative phenotype when cultured under these systems. PMID:27071933

  7. Surface Tension Drives the Orientation of Crystals at the Air-Water Interface.

    Science.gov (United States)

    Chevalier, Nicolas R; Guenoun, Patrick

    2016-07-21

    The fabrication of oriented crystalline thin films is essential for a range of applications ranging from semiconductors to optical components, sensors, and catalysis. Here we show by depositing micrometric crystal particles on a liquid interface from an aerosol phase that the surface tension of the liquid alone can drive the crystallographic orientation of initially randomly oriented particles. The X-ray diffraction patterns of the particles at the interface are identical to those of a monocrystalline sample cleaved along the {104} (CaCO3) or {111} (CaF2) face. We show how this orientation effect can be used to produce thin coatings of oriented crystals on a solid substrate. These results also have important implications for our understanding of heterogeneous crystal growth beneath amphiphile monolayers and for 2D self-assembly processes at the air-liquid interface. PMID:27389283

  8. Rate-dependent interface capture beyond the coffee-ring effect

    Science.gov (United States)

    Li, Yanan; Yang, Qiang; Li, Mingzhu; Song, Yanlin

    2016-04-01

    The mechanism of droplet drying is a widely concerned fundamental issue since controlling the deposition morphology of droplet has significant influence on printing, biology pattern, self-assembling and other solution-based devices fabrication. Here we reveal a striking different kinetics-controlled deposition regime beyond the ubiquitous coffee-ring effect that suspended particles tend to kinetically accumulate at the air-liquid interface and deposit uniformly. As the interface shrinkage rate exceeds the particle average diffusion rate, particles in vertical evaporation flow will be captured by the descending surface, producing surface particle jam and forming viscous quasi-solid layer, which dramatically prevents the trapped particles from being transported to drop edge and results in uniform deposition. This simple, robust drying regime will provide a versatile strategy to control the droplet deposition morphology, and a novel direction of interface assembling for fabricating superlattices and high quality photonic crystal patterns.

  9. Bio-hybrid interfaces to study neuromorphic functionalities: New multidisciplinary evidences of cell viability on poly(anyline) (PANI), a semiconductor polymer with memristive properties.

    Science.gov (United States)

    Juarez-Hernandez, Leon J; Cornella, Nicola; Pasquardini, Laura; Battistoni, Silvia; Vidalino, Laura; Vanzetti, Lia; Caponi, Silvia; Dalla Serra, Mauro; Iannotta, Salvatore; Pederzolli, Cecilia; Macchi, Paolo; Musio, Carlo

    2016-01-01

    The interfacing of artificial devices with biological systems is a challenging field that crosses several disciplines ranging from fundamental research (biophysical chemistry, neurobiology, material and surface science) to frontier technological application (nanotechnology, bioelectronics). The memristor is the fourth fundamental circuit element, whose electrical properties favor applications in signal processing, neural networks, and brain-computer interactions and it represents a new frontier for technological applications in many fields including the nanotechnologies, bioelectronics and the biosensors. Using multidisciplinary approaches, covering surface science, cell biology and electrophysiology, we successfully implemented a living bio-hybrid system constituted by cells adhering to films of poly(aniline) (PANI), a semiconductor polymer having memristive properties assembled with polyelectrolytes. Here we tested whether the PANI devices could support survivor, adhesion and differentiation of several cell lines, including the neuron-like SHSY5Y cells. Moreover, we performed electrophysiology on these cells showing that the biophysical properties are retained with differences occurring in the recorded ion currents. Taken together, the cell viability here reported is the key requirement to design and develop a reliable functional memristor-based bio-hybrid able to mimic neuronal activity and plasticity. PMID:26263829

  10. Differentiation of embryonic stem cells into corneal epithelium

    Institute of Scientific and Technical Information of China (English)

    WANG Zhichong; LIU Jingbo; GE Jian; HUANG Bing; GAO Qianying; LIU Bingqian; WANG Linghua; YU Ling; FAN Zhigang; LU Xiaoming

    2005-01-01

    Our project was to determine whether embryonic stem (ES) cells could be induced to differentiate into corneal epithelia by superficial corneoscleral limbal stroma. To achieve this goal, ES-GFP cell line D3 was pre-induced by retinoic acid (RA). The pre-induced cells were seeded on deepithelialized superficial corneoscleral slices (SCSS) to form a monolayer, and divided into three groups. Group 1 was cultured and passaged in vitro for direct detection. Group 2 was exposed to air-liquid interfaces for 10 days and implanted into the subcutaneous layer of nude mice for 2 weeks for further induction in vivo. Group 3 was cultured in vitro without any inducing factors for control. There were no teratomas found in nude mice which were implanted with differentiated ES cells after two weeks. The differentiated cells showed an appearance of epithelia both in vitro and in vivo. Expression of CK3, P63 and PCNA was detected by immunohistochemical staining in the differentiated cells in group 1 and 2. Microvillis and zonula occludens were observed on the surface of the differentiated cells under an electron microscope. In the control group, ES cells differentiated freely without any inducing factors. Most cells were shed and formed a neuronal dendrite-like structure, and a minority of cells appeared polymorphic. These results demonstrate that ES cells can differentiate into corneal epithelia on the surface of SCSS under the controlled condition. Differentiated ES cells could be used as epithelial seeding cells for the reconstruction of ocular surface and corneal tissue engineering in the future.

  11. Soft Interfaces

    Science.gov (United States)

    Gilles de Gennes, Pierre; Edwards, Introduction By Sam

    1997-04-01

    Paul Adrien Maurice Dirac, one of the greatest physicists of the twentieth century, died in 1984. Dirac's college, St. John's of Cambridge, generously endowed annual lectures to be held at Cambridge University in his memory. This volume contains a much expanded version of the 1994 Dirac Lecture by Nobel Laureate Pierre Gilles de Gennes. The book presents an impressionistic tour of the physics of soft interfaces. Full of insight and interesting asides, it not only provides an accessible introduction to this topic, but also lays down many markers and signposts that will be of interest to researchers in physics or chemistry. Features discussions of wetting and dewetting, the dynamics of different types of interface and adhesion and polymer/polymer welding.

  12. Interface learning

    DEFF Research Database (Denmark)

    Thorhauge, Sally

    2014-01-01

    students. The research focuses on the learning that the students experience in the interface of the two learning environments: The formal learning environment of the upper secondary school and the informal learning environment of the museum. Focus is also on the learning that the teachers and museum......"Interface learning - New goals for museum and upper secondary school collaboration" investigates and analyzes the learning that takes place when museums and upper secondary schools in Denmark work together in local partnerships to develop and carry out school-related, museum-based coursework for...... professionals experience as a result of their collaboration. The dissertation demonstrates how a given partnership’s collaboration affects the students’ learning experiences when they are doing the coursework. The dissertation presents findings that museum-school partnerships can use in order to develop the...

  13. Hypoxia-inducible factor regulates expression of surfactant protein in alveolar type II cells in vitro.

    Science.gov (United States)

    Ito, Yoko; Ahmad, Aftab; Kewley, Emily; Mason, Robert J

    2011-11-01

    Alveolar type II (ATII) cells cultured at an air-liquid (A/L) interface maintain differentiation, but they lose these properties when they are submerged. Others showed that an oxygen tension gradient develops in the culture medium as ATII cells consume oxygen. Therefore, we wondered whether hypoxia inducible factor (HIF) signaling could explain differences in the phenotypes of ATII cells cultured under A/L interface or submerged conditions. ATII cells were isolated from male Sprague-Dawley rats and cultured on inserts coated with a mixture of rat-tail collagen and Matrigel, in medium including 5% rat serum and 10 ng/ml keratinocyte growth factor, with their apical surfaces either exposed to air or submerged. The A/L interface condition maintained the expression of surfactant proteins, whereas that expression was down-regulated under the submerged condition, and the effect was rapid and reversible. Under submerged conditions, there was an increase in HIF1α and HIF2α in nuclear extracts, mRNA levels of HIF inducible genes, vascular endothelial growth factor, glucose transporter-1 (GLUT1), and the protein level of pyruvate dehydrogenase kinase isozyme-1. The expression of surfactant proteins was suppressed and GLUT1 mRNA levels were induced when cells were cultured with 1 mM dimethyloxalyl glycine. The expression of surfactant proteins was restored under submerged conditions with supplemented 60% oxygen. HIF signaling and oxygen tension at the surface of cells appears to be important in regulating the phenotype of rat ATII cells. PMID:21454802

  14. Museets interface

    DEFF Research Database (Denmark)

    Pold, Søren

    Søren Pold gør sig overvejelser med udgangspunkt i museumsprojekterne Kongedragter.dk og Stigombord.dk. Han argumenterer for, at udviklingen af internettets interfaces skaber nye måder at se, forstå og interagere med kulturen på. Brugerne får nye medievaner og perceptionsmønstre, der må medtænkes...

  15. Enhancing Perovskite Solar Cell Performance by Interface Engineering Using CH3NH3PbBr0.9I2.1 Quantum Dots.

    Science.gov (United States)

    Cha, Mingyang; Da, Peimei; Wang, Jun; Wang, Weiyi; Chen, Zhanghai; Xiu, Faxian; Zheng, Gengfeng; Wang, Zhong-Sheng

    2016-07-13

    To improve the interfacial charge transfer that is crucial to the performance of perovskite solar cells, the interface engineering in a device should be rationally designed. Here we have developed an interface engineering method to tune the photovoltaic performance of planar-heterojunction perovskite solar cells by incorporating MAPbBr3-xIx (MA = CH3NH3) quantum dots (QDs) between the MAPbI3 perovskite film and the hole-transporting material (HTM) layer. By adjustment of the Br:I ratio, the as-synthesized MAPbBr3-xIx QDs show tunable fluorescence and band edge positions. When the valence band (VB) edge of MAPbBr3-xIx QDs is located below that of the MAPbI3 perovskite, the hole transfer from the MAPbI3 perovskite film to the HTM layer is hindered, and hence, the power conversion efficiency decreases. In contrast, when the VB edge of MAPbBr3-xIx QDs is located between the VB edge of the MAPbI3 perovskite film and the highest occupied molecular orbital of the HTM layer, the hole transfer from the MAPbI3 perovskite film to the HTM layer is well-facilitated, resulting in significant improvements in the fill factor, short-circuit photocurrent, and power conversion efficiency. PMID:27345104

  16. Evolution of a Native Oxide Layer at the a-Si:H/c-Si Interface and Its Influence on a Silicon Heterojunction Solar Cell.

    Science.gov (United States)

    Liu, Wenzhu; Meng, Fanying; Zhang, Xiaoyu; Liu, Zhengxin

    2015-12-01

    The interface microstructure of a silicon heterojunction (SHJ) solar cell was investigated. We found an ultrathin native oxide layer (NOL) with a thickness of several angstroms was formed on the crystalline silicon (c-Si) surface in a very short time (∼30 s) after being etched by HF solution. Although the NOL had a loose structure with defects that are detrimental for surface passivation, it acted as a barrier to restrain the epitaxial growth of hydrogenated amorphous silicon (a-Si:H) during the plasma-enhanced chemical vapor deposition (PECVD). The microstructure change of the NOL during the PECVD deposition of a-Si:H layers with different conditions and under different H2 plasma treatments were systemically investigated in detail. When a brief H2 plasma was applied to treat the a-Si:H layer after the PECVD deposition, interstitial oxygen and small-size SiO2 precipitates were transformed to hydrogenated amorphous silicon suboxide alloy (a-SiO(x):H, x ∼ 1.5). In the meantime, the interface defect density was reduced by about 50%, and the parameters of the SHJ solar cell were improved due to the post H2 plasma treatment. PMID:26565116

  17. Histopathology and immune histochemistry of red tattoo reactions. Interface dermatitis is the lead pathology, with increase in T-lymphocytes and Langerhans cells suggesting an allergic pathomechanism

    DEFF Research Database (Denmark)

    Høgsberg, T; Thomsen, B M; Serup, J

    2015-01-01

    BACKGROUND: The majority of tattoo reactions are affiliated to red pigmented areas and often suspected to be allergic in nature. A sizeable series of biopsies of such reactions has not previously been performed. The aim of this study was to type and grade epidermal and dermal changes in tattoo...... reactions to red/red nuances by microscopy and immunochemistry relevant for the assessment of a possible allergic pathomechanism. METHODS: Skin biopsies were taken from red tattoo reactions, graded by conventional microscopy and stained for T and B-lymphocytes, Langerhans cells, macrophages and tumour......-α was common. CONCLUSION: The predominant histological pattern of chronic tattoo reactions in red/red nuances is interface dermatitis. T-lymphocytes and Langerhans cells are increased suggesting an allergic pathomechanism. TNF-α may contribute to reactions. In many cases, overlapping reactive patterns...

  18. Surface properties of fluoroethylene carbonate-derived solid electrolyte interface on graphite negative electrode by narrow-range cycling in cell formation process

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • A new method to improve cell performance through an FEC-derived SEI layer on the graphite anode using narrow-range cycling in the formation process is presented. • A linkage structure of submicron-sized particles on the SEI film layer largely developed by narrow-range cycling in the formation process. • The application of narrow-range cycling with an FEC additive in the formation process improves the cycling performance and Coulombic efficiency of the cell. - Abstract: A modified solid electrolyte interface (SEI) on a graphite negative electrode with a fluoroethylene carbonate (FEC) additive was prepared by narrow-range cycling in a cell formation process. The SEI surface properties were investigated by extreme high-resolution scanning electron microscopy (XHR-SEM) under low acceleration voltage and X-ray photoelectron spectroscopy (XPS). A linkage structure of submicron-sized particles on the SEI film layer largely developed by narrow-range cycling in the formation process; these particles were mainly composed of the inorganic component (P-F bonding states, LiPxOyFz) from the FEC. The application of narrow-range cycling with an FEC additive in the formation process improves the cycling performance and Coulombic efficiency of the cell. It is suggested that the SEI layer modified with FEC-derived SEI components on the graphite anode electrode by narrow-range cycling in the formation process, could improve the cell performance

  19. Tissue engineering and the use of stem/progenitor cells for airway epithelium repair

    Directory of Open Access Journals (Sweden)

    GM Roomans

    2010-06-01

    Full Text Available Stem/progenitor cells can be used to repair defects in the airway wall, resulting from e.g., tumors, trauma, tissue reactions following long-time intubations, or diseases that are associated with epithelial damage. Several potential sources of cells for airway epithelium have been identified. These can be divided into two groups. The first group consists of endogenous progenitor cells present in the respiratory tract. This group can be subdivided according to location into (a a ductal cell type in the submucosal glands of the proximal trachea, (b basal cells in the intercartilaginous zones of the lower trachea and bronchi, (c variant Clara cells (Clarav-cells in the bronchioles and (d at the junctions between the bronchioles and the alveolar ducts, and (e alveolar type II cells. This classification of progenitor cell niches is, however, controversial. The second group consists of exogenous stem cells derived from other tissues in the body. This second group can be subdivided into: (a embryonic stem (ES cells, induced pluripotent stem (iPS cells, or amniotic fluid stem cells, (b side-population cells from bone marrow or epithelial stem cells present in bone marrow or circulation and (c fat-derived mesenchymal cells. Airway epithelial cells can be co-cultured in a system that includes a basal lamina equivalent, extracellular factors from mesenchymal fibroblasts, and in an air-liquid interface system. Recently, spheroid-based culture systems have been developed. Several clinical applications have been suggested: cystic fibrosis, acute respiratory distress syndrome, chronic obstructive lung disease, pulmonary fibrosis, pulmonary edema, and pulmonary hypertension. Clinical applications so far are few, but include subglottic stenosis, tracheomalacia, bronchiomalacia, and emphysema.

  20. Illustration of extensive extracellular matrix at the epithelial-mesenchymal interface within the renal stem/progenitor cell niche

    Directory of Open Access Journals (Sweden)

    Minuth Will W

    2012-09-01

    Full Text Available Abstract Background Stem/progenitor cells are promising candidates to treat diseased renal parenchyma. However, implanted stem/progenitor cells are exposed to a harmful atmosphere of degenerating parenchyma. To minimize hampering effects after an implantation investigations are in progress to administer these cells within an artificial polyester interstitum supporting survival. Learning from nature the renal stem/progenitor cell niche appears as a valuable model. At this site epithelial stem/progenitor cells within the collecting duct ampulla face mesenchymal stem/progenitor cells. Both cell types do not have close contact but are separated by a wide interstitium. Methods To analyze extracellular matrix in this particular interstitium, special contrasting for transmission electron microscopy was performed. Kidneys of neonatal rabbits were fixed in solutions containing glutaraldehyde (GA or in combination with cupromeronic blue, ruthenium red and tannic acid. Results GA revealed a basal lamina at the ampulla and a bright but inconspicuously looking interstitial space. In contrast, GA containing cupromeronic blue exhibits numerous proteoglycan braces lining from the ampulla towards the interstitial space. GA containing ruthenium red or tannic acid demonstrates clouds of extracellular matrix protruding from the basal lamina of the ampulla to the surface of mesenchymal stem/progenitor cells. Conclusions The actual data show that the interstitium between epithelial and mesenchymal stem/progenitor cells contains much more and up to date unknown extracellular matrix than earlier observed by classical GA fixation.

  1. Artificial skin--culturing of different skin cell lines for generating an artificial skin substitute on cross-weaved spider silk fibres.

    Directory of Open Access Journals (Sweden)

    Hanna Wendt

    Full Text Available BACKGROUND: In the field of Plastic Reconstructive Surgery the development of new innovative matrices for skin repair is in urgent need. The ideal biomaterial should promote attachment, proliferation and growth of cells. Additionally, it should degrade in an appropriate time period without releasing harmful substances, but not exert a pathological immune response. Spider dragline silk from Nephila spp meets these demands to a large extent. METHODOLOGY/PRINCIPAL FINDINGS: Native spider dragline silk, harvested directly out of Nephila spp spiders, was woven on steel frames. Constructs were sterilized and seeded with fibroblasts. After two weeks of cultivating single fibroblasts, keratinocytes were added to generate a bilayered skin model, consisting of dermis and epidermis equivalents. For the next three weeks, constructs in co-culture were lifted on an originally designed setup for air/liquid interface cultivation. After the culturing period, constructs were embedded in paraffin with an especially developed program for spidersilk to avoid supercontraction. Paraffin cross-sections were stained in Haematoxylin & Eosin (H&E for microscopic analyses. CONCLUSION/SIGNIFICANCE: Native spider dragline silk woven on steel frames provides a suitable matrix for 3 dimensional skin cell culturing. Both fibroblasts and keratinocytes cell lines adhere to the spider silk fibres and proliferate. Guided by the spider silk fibres, they sprout into the meshes and reach confluence in at most one week. A well-balanced, bilayered cocultivation in two continuously separated strata can be achieved by serum reduction, changing the medium conditions and the cultivation period at the air/liquid interphase. Therefore spider silk appears to be a promising biomaterial for the enhancement of skin regeneration.

  2. The majority of murine γδ T cells at the maternal-fetal interface in pregnancy produce IL-17.

    Science.gov (United States)

    Pinget, Gabriela V; Corpuz, Theresa M; Stolp, Jessica; Lousberg, Erin L; Diener, Kerrilyn R; Robertson, Sarah A; Sprent, Jonathan; Webster, Kylie E

    2016-08-01

    Compared with lymphoid tissues, the immune cell compartment at mucosal sites is enriched with T cells bearing the γδ T-cell receptor (TCR). The female reproductive tract, along with the placenta and uterine decidua during pregnancy, are populated by γδ T cells predominantly expressing the invariant Vγ6(+)Vδ1(+) receptor. Surprisingly little is understood about the function of these cells. We found that the majority of γδ T cells in the non-pregnant uterus, pregnant uterus, decidua and placenta of mice express the transcription factor RORγt and produce interleukin-17 (IL-17). In contrast, IFNγ-producing γδ T cells were markedly reduced in gestational tissues compared with uterine-draining lymph nodes and spleen. Both uterine-resident invariant Vγ6(+) and Vγ4(+) γδ T cells which are more typically found in lymphoid tissues and circulating blood, were found to express IL-17. Vγ4(+) γδ T cells were particularly enriched in the placenta, suggesting a pregnancy-specific recruitment or expansion of these cells. A small increase in IL-17-producing γδ T cells was observed in allogeneic compared with syngeneic pregnancy, suggesting a contribution to regulating the maternal response to paternally-derived alloantigens. However, their high proportions also in non-pregnant uteri and gestational tissues of syngeneic pregnancy imply a role in the prevention of intrauterine infection or quality control of fetal development. These data suggest the need for a more rigorous evaluation of the role of IL-17 in sustaining normal pregnancy, particularly as emerging data points to a pathogenic role for IL-17 in pre-eclampsia, pre-term birth, miscarriage and maternal immune activation-induced behavioral abnormalities in offspring. PMID:27241697

  3. Evaluation of E-Cigarette Liquid Vapor and Mainstream Cigarette Smoke after Direct Exposure of Primary Human Bronchial Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Stefanie Scheffler

    2015-04-01

    Full Text Available E-cigarettes are emerging products, often described as “reduced-risk” nicotine products or alternatives to combustible cigarettes. Many smokers switch to e-cigarettes to quit or significantly reduce smoking. However, no regulations for e-cigarettes are currently into force, so that the quality and safety of e-liquids is not necessarily guaranteed. We exposed primary human bronchial epithelial cells of two different donors to vapor of e-cigarette liquid with or without nicotine, vapor of the carrier substances propylene glycol and glycerol as well as to mainstream smoke of K3R4F research cigarettes. The exposure was done in a CULTEX® RFS compact  module, allowing the exposure of the cells at the air-liquid interface. 24 h post-exposure, cell viability and oxidative stress levels in the cells were analyzed. We found toxicological effects of e-cigarette vapor and the pure carrier substances, whereas the nicotine concentration did not have an effect on the cell viability. The viability of mainstream smoke cigarette exposed cells was 4.5–8 times lower and the oxidative stress levels 4.5–5 times higher than those of e-cigarette vapor exposed cells, depending on the donor. Our experimental setup delivered reproducible data and thus provides the opportunity for routine testing of e-cigarette liquids to ensure safety and quality for the user.

  4. Soft Interfaces

    International Nuclear Information System (INIS)

    This book presents an extended form of the 1994 Dirac Memorial Lecture delivered by Pierre Gilles de Gennes at Cambridge University. The main task of the presentation is to show the beauty and richness of structural forms and phenomena which are observed at soft interfaces between two media. They are much more complex than forms and phenomena existing in each phase separately. Problems are discussed including both traditional, classical techniques, such as the contact angle in static and dynamic partial wetting, as well as the latest research methodology, like 'environmental' scanning electron microscopes. The book is not a systematic lecture on phenomena but it can be considered as a compact set of essays on topics which particularly fascinate the author. The continuum theory widely used in the book is based on a deep molecular approach. The author is particularly interested in a broad-minded rheology of liquid systems at interfaces with specific emphasis on polymer melts. To study this, the author has developed a special methodology called anemometry near walls. The second main topic presented in the book is the problem of adhesion. Molecular processes, energy transformations and electrostatic interaction are included in an interesting discussion of the many aspects of the principles of adhesion. The third topic concerns welding between two polymer surfaces, such as A/A and A/B interfaces. Of great worth is the presentation of various unsolved, open problems. The kind of topics and brevity of description indicate that this book is intended for a well prepared reader. However, for any reader it will present an interesting picture of how many mysterious processes are acting in the surrounding world and how these phenomena are perceived by a Nobel Laureate, who won that prize mainly for his investigations in this field. (book review)

  5. Effect of the interface glass on electrical performance of screen printed Ag thick-film contacts of Si solar cells

    International Nuclear Information System (INIS)

    Glasses with compositions (40 - x)PbO--xZnO--60(B2O3--SiO2) (x = 5, 10, 15, 20) have been prepared. Substitution of ZnO for PbO increased glass bandgap (Eg) and crystallization ability greatly. Crystalline phases of bulk glasses after rapid thermal processing (RTP) were identified by X-ray diffraction (XRD). Transmission line model (TLM) was employed to measure the electrical performance of Ag electrodes screen printed on polycrystalline Si substrates using Ag thick-film pastes and by RTP. The conductivity (σ) decreased while specific contact resistance (ρc) was not monotonic varied with increasing ZnO content. The correlation between electrical performance and glass barrier formed on the Ag gridline and Si emitter interface has been investigated.

  6. Design of the integration interface between the EU HCPB TBM and the ITER TBM port plug including hot cell operations for connection

    International Nuclear Information System (INIS)

    In the frame of the activities of the EU Breeder Blanket Programme and of the Test Blanket Working Group, the Helium Cooled Pebble Bed Test Blanket Module- (HCPB-TBM) System is developed. The TBM test schedule foresees four different campaigns for simulation of DEMO relevant conditions, campaign requires a dedicate TBM. Therefore a concept for TBM integration into ITER is designed with attention to simplify the mounting/dismounting operations. This paper presents the status of this concept with regard to the operations in hot cell required to install a new TBM into an equatorial TBM Port Plug (PP). This includes the establishment of the connection for the attachment, supply- and diagnostic lines in the environment of the interface (IF 1) between the TBM rear part and the PP backside shield. The connection of IF 1 has to be designed to cope with a temperature difference between TBM and PP (∝200 K) and the EM-loads during normal operation and disruption scenarios. The reference attachment concept based on shear keys and flexible cartridges is revised to cope with new conditions on the load and at the interface to the PP. According to the latest results of EM analysis, a radial component of the Maxwell forces (due to the ferromagnetic structural material) has been identified as an additional challenging load for the attachment. Furthermore, the replacing operations at IF 1 are influenced by the design of the PP; the recent ITER proposal based on a removable back side shield allows access to the IF 1 from the periphery after the frame of the PP surrounding the TBM is removed. As for the mechanical attachment, the tools and operations for connection of the TBM supply lines (Helium-, Purge- and measurement lines for different purpose depending on the test schedule) are strongly influenced by the restrictions to access IF 1, too. Dismantling of the frame would allow direct access to the interface by e.g. orbital welding tools. The concept for connection of the TBM

  7. Design of the integration interface between the EU HCPB TBM and the ITER TBM port plug including hot cell operations for connection

    Energy Technology Data Exchange (ETDEWEB)

    Neuberger, H.; Boccaccini, L.V.; Roccella, R. [Forschungszentrum Karlsruhe (Germany). Euratom Association; Tesini, A.; Bede, O. [ITER International Team-Cadarache Joint Work Site, Saint-Paul-lez-Durance (France)

    2007-07-01

    In the frame of the activities of the EU Breeder Blanket Programme and of the Test Blanket Working Group, the Helium Cooled Pebble Bed Test Blanket Module- (HCPB-TBM) System is developed. The TBM test schedule foresees four different campaigns for simulation of DEMO relevant conditions, campaign requires a dedicate TBM. Therefore a concept for TBM integration into ITER is designed with attention to simplify the mounting/dismounting operations. This paper presents the status of this concept with regard to the operations in hot cell required to install a new TBM into an equatorial TBM Port Plug (PP). This includes the establishment of the connection for the attachment, supply- and diagnostic lines in the environment of the interface (IF 1) between the TBM rear part and the PP backside shield. The connection of IF 1 has to be designed to cope with a temperature difference between TBM and PP ({proportional_to}200 K) and the EM-loads during normal operation and disruption scenarios. The reference attachment concept based on shear keys and flexible cartridges is revised to cope with new conditions on the load and at the interface to the PP. According to the latest results of EM analysis, a radial component of the Maxwell forces (due to the ferromagnetic structural material) has been identified as an additional challenging load for the attachment. Furthermore, the replacing operations at IF 1 are influenced by the design of the PP; the recent ITER proposal based on a removable back side shield allows access to the IF 1 from the periphery after the frame of the PP surrounding the TBM is removed. As for the mechanical attachment, the tools and operations for connection of the TBM supply lines (Helium-, Purge- and measurement lines for different purpose depending on the test schedule) are strongly influenced by the restrictions to access IF 1, too. Dismantling of the frame would allow direct access to the interface by e.g. orbital welding tools. The concept for connection of

  8. Structure and interface chemistry of MoO3 back contacts in Cu(In,Ga)Se2 thin film solar cells

    International Nuclear Information System (INIS)

    Molybdenum oxide (MoO3) is considered as a possible primary back contact for Cu(InGa)Se2 thin film solar cells for its potential as a transparent back contact for superstrate and bifacial devices. MoO3 films were deposited on Mo or ITO-coated soda lime glass substrates by reactive rf sputtering in an ambient of Ar + O2 with O2/(O2 + Ar) = 35% on which Cu(In0.7Ga0.3)Se2 alloy absorber layers were deposited using multi-source elemental evaporation. Scanning Electron Microscopy studies showed uniform coverage of the as-deposited MoO3 layer and good adhesion was obtained in all cases. X-ray Photoelectron Spectroscopy depth profile analysis showed that MoSe2 was not formed at the Cu(InGa)Se2 interface with either the Mo-MoO3 or ITO-MoO3 back contacts. Determination of the valence band offsets showed that the MoO3 layer at the interface changes the energy band alignment with Cu(InGa)Se2, producing a primary contact with lower valence band offset than ITO. Cu(In,Ga)Se2 thin film solar cells prepared using an as-deposited Mo-MoO3 back contact yielded a best conversion efficiency of 14%, with VOC = 647 mV, JSC = 28.4 mA/cm2, and FF = 78.1%. Cells with ITO-MoO3 back contact showed a best efficiency of 12%, with VOC = 642 mV, JSC = 26.8 mA/cm2, and FF = 69.2%

  9. Structure and interface chemistry of MoO3 back contacts in Cu(In,Ga)Se2 thin film solar cells

    Science.gov (United States)

    Simchi, Hamed; McCandless, Brian E.; Meng, T.; Shafarman, William N.

    2014-01-01

    Molybdenum oxide (MoO3) is considered as a possible primary back contact for Cu(InGa)Se2 thin film solar cells for its potential as a transparent back contact for superstrate and bifacial devices. MoO3 films were deposited on Mo or ITO-coated soda lime glass substrates by reactive rf sputtering in an ambient of Ar + O2 with O2/(O2 + Ar) = 35% on which Cu(In0.7Ga0.3)Se2 alloy absorber layers were deposited using multi-source elemental evaporation. Scanning Electron Microscopy studies showed uniform coverage of the as-deposited MoO3 layer and good adhesion was obtained in all cases. X-ray Photoelectron Spectroscopy depth profile analysis showed that MoSe2 was not formed at the Cu(InGa)Se2 interface with either the Mo-MoO3 or ITO-MoO3 back contacts. Determination of the valence band offsets showed that the MoO3 layer at the interface changes the energy band alignment with Cu(InGa)Se2, producing a primary contact with lower valence band offset than ITO. Cu(In,Ga)Se2 thin film solar cells prepared using an as-deposited Mo-MoO3 back contact yielded a best conversion efficiency of 14%, with VOC = 647 mV, JSC = 28.4 mA/cm2, and FF = 78.1%. Cells with ITO-MoO3 back contact showed a best efficiency of 12%, with VOC = 642 mV, JSC = 26.8 mA/cm2, and FF = 69.2%.

  10. Interfaces between dendritic cells, other immune cells, and nerve fibres in mouse Peyer's patches: potential sites for neuroinvasion in prion diseases.

    Science.gov (United States)

    Defaweux, Valérie; Dorban, Gauthier; Demonceau, Caroline; Piret, Joëlle; Jolois, Olivier; Thellin, Olivier; Thielen, Caroline; Heinen, Ernst; Antoine, Nadine

    2005-01-01

    In this study, we examined where immune cells and nerve fibres are located in mouse Peyer's patches, with a view to identifying potential sites for neuroinvasion by prions. Special attention was paid to dendritic cells, viewed as candidate transporters of infectious prion. Double immunofluorescence labellings with anti-CD11c antibody and marker for other immune cells (B cells, T cells, follicular dendritic cells) were carried out and analysed by confocal microscopy on Peyer's patch cryosections. To reveal the extensive ganglionated networks of the myenteric and submucosal plexi and the sparse meshworks of nerve strands, we used antibodies directed against different neurofilament subunits or against glial fibrillary acidic protein. In the suprafollicular dome, dendritic cells connect, via their cytoplasmic extensions, enterocytes with M cells of the follicle-associated epithelium. They are also close to B and T cells. Nerve fibres are detected in the suprafollicular dome, notably in contact with dendritic cells. Similar connections between dendritic cells, T cells, and nerve fibres are seen in the interfollicular region. Germinal centres are not innervated; inside them dendritic cells establish contacts with follicular dendritic cells and with B cells. After immunolabelling of normal prion protein, dendritic cells of the suprafollicular dome are intensely positive labelled. PMID:15816033

  11. Optical Neural Interfaces

    OpenAIRE

    Warden, Melissa R.; Cardin, Jessica A.; Deisseroth, Karl

    2014-01-01

    Genetically encoded optical actuators and indicators have changed the landscape of neuroscience, enabling targetable control and readout of specific components of intact neural circuits in behaving animals. Here, we review the development of optical neural interfaces, focusing on hardware designed for optical control of neural activity, integrated optical control and electrical readout, and optical readout of population and single-cell neural activity in freely moving mammals.

  12. Integration of Rabbit Adipose Derived Mesenchymal Stem Cells to Hydroxyapatite Burr Hole Button Device for Bone Interface Regeneration

    Science.gov (United States)

    Gayathri, Viswanathan; Harikrishnan, Varma; Mohanan, Parayanthala Valappil

    2016-01-01

    Adipose Derived Mesenchymal Stem Cells, multipotent stem cells isolated from adipose tissue, present close resemblance to the natural in vivo milieu and microenvironment of bone tissue and hence widely used for in bone tissue engineering applications. The present study evaluates the compatibility of tissue engineered hydroxyapatite burr hole button device (HAP-BHB) seeded with Rabbit Adipose Derived Mesenchymal Stem Cells (ADMSCs). Cytotoxicity, oxidative stress response, apoptotic behavior, attachment, and adherence of adipose MSC seeded on the device were evaluated by scanning electron and confocal microscopy. The results of the MTT (3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium bromide) assay indicated that powdered device material was noncytotoxic up to 0.5 g/mL on cultured cells. It was also observed that oxidative stress related reactive oxygen species production and apoptosis on cell seeded device were similar to those of control (cells alone) except in 3-day period which showed increased reactive oxygen species generation. Further scanning electron and confocal microscopy indicated a uniform attachment of cells and viability up to 200 μm deep inside the device, respectively. Based on the results, it can be concluded that the in-house developed HAP-BHB device seeded with ADMSCs is nontoxic/safe compatible device for biomedical application and an attractive tissue engineered device for calvarial defect regeneration. PMID:26880922

  13. Barrier height determination on Schottky contacts formed at the back contact-semiconductor interface of degraded solar cells

    Science.gov (United States)

    Misiakos, K.; Lathrop, J. W.

    A method is described of determining an equivalent circuit for solar cells which have degraded as a result of the formation of a rectifying Schottky barrier at the back contact. An excellent fit of experimental data has been achieved using SCEPTRE with an equivalent circuit derived from the shape of the measured current voltage characteristics. One key parameter of the Schottky barrier diode, the reverse saturation current, can be used to determine the barrier potential. The barrier potential increases as the cell is stressed with 0.5 volts being a typical experimentally determined value for a degraded cell.

  14. Gastrointestinal cell lines form polarized epithelia with an adherent mucus layer when cultured in semi-wet interfaces with mechanical stimulation.

    Directory of Open Access Journals (Sweden)

    Nazanin Navabi

    Full Text Available Mucin glycoproteins are secreted in large quantities by mucosal epithelia and cell surface mucins are a prominent feature of the glycocalyx of all mucosal epithelia. Currently, studies investigating the gastrointestinal mucosal barrier use either animal experiments or non-in vivo like cell cultures. Many pathogens cause different pathology in mice compared to humans and the in vitro cell cultures used are suboptimal because they are very different from an in vivo mucosal surface, are often not polarized, lack important components of the glycocalyx, and often lack the mucus layer. Although gastrointestinal cell lines exist that produce mucins or polarize, human cell line models that reproducibly create the combination of a polarized epithelial cell layer, functional tight junctions and an adherent mucus layer have been missing until now. We trialed a range of treatments to induce polarization, 3D-organization, tight junctions, mucin production, mucus secretion, and formation of an adherent mucus layer that can be carried out using standard equipment. These treatments were tested on cell lines of intestinal (Caco-2, LS513, HT29, T84, LS174T, HT29 MTX-P8 and HT29 MTX-E12 and gastric (MKN7, MKN45, AGS, NCI-N87 and its hTERT Clone5 and Clone6 origins using Ussing chamber methodology and (immunohistology. Semi-wet interface culture in combination with mechanical stimulation and DAPT caused HT29 MTX-P8, HT29 MTX-E12 and LS513 cells to polarize, form functional tight junctions, a three-dimensional architecture resembling colonic crypts, and produce an adherent mucus layer. Caco-2 and T84 cells also polarized, formed functional tight junctions and produced a thin adherent mucus layer after this treatment, but with less consistency. In conclusion, culture methods affect cell lines differently, and testing a matrix of methods vs. cell lines may be important to develop better in vitro models. The methods developed herein create in vitro mucosal surfaces

  15. Interfacing of science, medicine and law: The stem cell patent controversy in the United States and the European Union

    Directory of Open Access Journals (Sweden)

    Sonya eDavey

    2015-11-01

    Full Text Available The patent eligibility of stem cells – particularly those derived from human embryos – has long been under debate in both the scientific and legal communities. On the basis of moral grounds, the European Patent Office (EPO has refrained from granting patents for stem cells obtained through the destruction of human embryos. On the contrary, the United States Patent and Trademark Office (USPTO has historically granted patents regarding the isolation and use of human embryonic and other stem cells. To date, these US patents remain valid despite an increasing onslaught of challenges in court. However, recent precedents established in US courts significantly narrow the scope of patent eligibility within biotechnology. This article compares the implications of recent legal changes on stem cell patent eligibility between the EU and US.

  16. Interfacing of Science, Medicine and Law: The Stem Cell Patent Controversy in the United States and the European Union.

    Science.gov (United States)

    Davey, Sonya; Davey, Neil; Gu, Qian; Xu, Na; Vatsa, Rajet; Devalaraja, Samir; Harris, Paul; Gannavaram, Sreenivas; Dave, Raj; Chakrabarty, Ananda

    2015-01-01

    The patent eligibility of stem cells-particularly those derived from human embryos-has long been under debate in both the scientific and legal communities. On the basis of moral grounds, the European Patent Office (EPO) has refrained from granting patents for stem cells obtained through the destruction of human embryos. On the contrary, the United States Patent and Trademark Office (USPTO) has historically granted patents regarding the isolation and use of human embryonic and other stem cells. To date, these US patents remain valid despite an increasing onslaught of challenges in court. However, recent precedents established in US courts significantly narrow the scope of patent eligibility within biotechnology. This article compares the implications of recent legal changes on stem cell patent eligibility between the EU and US. PMID:26618158

  17. OEFinder: a user interface to identify and visualize ordering effects in single-cell RNA-seq data

    OpenAIRE

    Leng, Ning; Choi, Jeea; Chu, Li-Fang; Thomson, James A.; Kendziorski, Christina; Stewart, Ron

    2016-01-01

    Summary: A recent article identified an artifact in multiple single-cell RNA-seq (scRNA-seq) datasets generated by the Fluidigm C1 platform. Specifically, Leng et al. showed significantly increased gene expression in cells captured from sites with small or large plate output IDs. We refer to this artifact as an ordering effect (OE). Including OE genes in downstream analyses could lead to biased results. To address this problem, we developed a statistical method and software called OEFinder to...

  18. Interfacing of Science, Medicine and Law: The Stem Cell Patent Controversy in the United States and the European Union

    OpenAIRE

    Davey, Sonya; Davey, Neil; Gu, Qian; Xu, Na; Vatsa, Rajet; Devalaraja, Samir; Harris, Paul; Gannavaram, Sreenivas; Dave, Raj; Chakrabarty, Ananda

    2015-01-01

    The patent eligibility of stem cells–particularly those derived from human embryos–has long been under debate in both the scientific and legal communities. On the basis of moral grounds, the European Patent Office (EPO) has refrained from granting patents for stem cells obtained through the destruction of human embryos. On the contrary, the United States Patent and Trademark Office (USPTO) has historically granted patents regarding the isolation and use of human embryonic and other stem cells...

  19. Interfacing of science, medicine and law: The stem cell patent controversy in the United States and the European Union

    OpenAIRE

    Sonya eDavey; Neil eDavey; Qian eGu; Na eXu; Rajet eVatsa; Samir eDevalaraja; Paul eHarris; Sreenivas eGannavaram; Raj eDave; Ananda eChakrabarty

    2015-01-01

    The patent eligibility of stem cells – particularly those derived from human embryos – has long been under debate in both the scientific and legal communities. On the basis of moral grounds, the European Patent Office (EPO) has refrained from granting patents for stem cells obtained through the destruction of human embryos. On the contrary, the United States Patent and Trademark Office (USPTO) has historically granted patents regarding the isolation and use of human embryonic and other stem c...

  20. Regeneration of the lung: Lung stem cells and the development of lung mimicking devices.

    Science.gov (United States)

    Schilders, Kim A A; Eenjes, Evelien; van Riet, Sander; Poot, André A; Stamatialis, Dimitrios; Truckenmüller, Roman; Hiemstra, Pieter S; Rottier, Robbert J

    2016-01-01

    Inspired by the increasing burden of lung associated diseases in society and an growing demand to accommodate patients, great efforts by the scientific community produce an increasing stream of data that are focused on delineating the basic principles of lung development and growth, as well as understanding the biomechanical properties to build artificial lung devices. In addition, the continuing efforts to better define the disease origin, progression and pathology by basic scientists and clinicians contributes to insights in the basic principles of lung biology. However, the use of different model systems, experimental approaches and readout systems may generate somewhat conflicting or contradictory results. In an effort to summarize the latest developments in the lung epithelial stem cell biology, we provide an overview of the current status of the field. We first describe the different stem cells, or progenitor cells, residing in the homeostatic lung. Next, we focus on the plasticity of the different cell types upon several injury-induced activation or repair models, and highlight the regenerative capacity of lung cells. Lastly, we summarize the generation of lung mimics, such as air-liquid interface cultures, organoids and lung on a chip, that are required to test emerging hypotheses. Moreover, the increasing collaboration between distinct specializations will contribute to the eventual development of an artificial lung device capable of assisting reduced lung function and capacity in human patients. PMID:27107715

  1. Interleukin-1β mediates human airway epithelial cell migration via NF-κB

    Science.gov (United States)

    White, Steven R.; Fischer, Bernard M.; Marroquin, Bertha A.; Stern, Randi

    2008-01-01

    Migration of airway epithelial cells (AEC) is a necessary component of airway mucosal repair after injury. The cytokine IL-1β, present in airway inflammation, has protean effects on constituent cells within the mucosa, but its effects on epithelial repair are not known. We examined migration in differentiated primary human AEC grown in air-liquid interface culture for up to 3 wk and in the 16HBE14o− cell line. Wounds were created by mechanical abrasion and followed to closure using digital microscopy. Concurrent treatment with IL-1β (≤10 ng/ml) significantly accelerated migration in primary differentiated cells and in the 16HBE14o− cell line but did not accelerate migration in primary differentiated AEC collected from asthmatic donors. IL-1β treatment did not augment phosphorylation of stress-activated protein kinases normally activated by mechanical injury, such as heat shock protein 27, ERK1/2, and JNK, and did not elicit phosphorylation of signal transducer and activator of transcription-3. However, introduction of a silencing RNA to block expression of the p65 component of NF-κB blocked IL-1β-accelerated migration substantially. Our data demonstrate that IL-1β accelerates migration of normal, but not asthmatic, differentiated AEC by a mechanism that requires activation of the NF-κB signaling complex and suggests a trophic role for this cytokine in airway epithelial repair after injury. PMID:18849440

  2. Investigation into the diffusion and oxidation behavior of the interface between a plasma-sprayed anode and a porous steel support for solid oxide fuel cells

    Science.gov (United States)

    Zhang, Shan-Lin; Li, Cheng-Xin; Li, Chang-Jiu; Liu, Meilin; Yang, Guan-Jun

    2016-08-01

    Porous metal-supported solid oxide fuel cells (SOFCs) have attracted much attention because their potential to dramatically reduce the cost while enhancing the robustness and manufacturability. In particular, 430 ferritic steel (430L) is one of the popular choice for SOFC support because of its superior performance and low cost. In this study, we investigate the oxidation and diffusion behavior of the interface between a Ni-based anode and porous 430L support exposed to a humidified (3% H2O) hydrogen atmosphere at 700 °C. The Ni-GDC (Ce0.8Gd0.2O2-δ) cermet anodes are deposited on the porous 430L support by atmospheric plasma spraying (APS). The effect of exposure time on the microstructure and phase structure of the anode and the supports is studied and the element diffusion across the support/anode interface is characterized. Results indicate that the main oxidation product of the 430L support is Cr2O3, and that Cr and Fe will diffuse to the anode and the diffusion thickness increases with the exposure time. The diffusion thickness of Cr and Fe reach about 5 and 2 μm, respectively, after 1000 h exposure. However, the element diffusion and oxidation has little influence on the area-specific resistance, indicating that the porous 430L steel and plasma sprayed Ni-GDC anode are promising for durable SOFCs.

  3. Interface studies on the tunneling contact of a MOCVD-prepared tandem solar cell; Grenzflaechenuntersuchungen am Tunnelkontakt einer MOCVD-praeparierten Tandemsolarzelle

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, U.

    2007-07-10

    In this thesis a tandem solar cell with a novel tunneling contact was developed. For the development of the monolithic preparation especailly critical hetero-interfaces were studied in the region of the tunneling contact with surface-sensitive measuring method. The tandem solar cell consisted of single solar cells with absorber layers of In{sub 0.53}Ga{sub 0.47}As (E{sub g}=0.73 eV) and In{sub 0.78}Ga{sub 0.22}As{sub 0.491}P{sub 0.51} (E{sub g}=1.03 eV), the serial switching of which was pursued with a tunneling contact (ESAKI diode, which consisted of a very thin n-doped InGaAs and a p-doped GaAsSb layer. The III-V semiconductor layers were prepared by metalorganic gas phase epitaxy (MOCVD) monocrystallinely on an InP(100) substrate lattice-matchedly. Especially the influence of the preparation of InGaAs surfaces on the sharpness of the InGaAs/GaAsSb interface was in-situ studied by reflection-anisotropy spectroscopy and after a contamination-free transfer into the ultrahigh vacuum with photoelectron spectroscopy and with low-energetic electron diffraction (LEED). Thereby for the first time three different reconstructions of the MOCVD-prepared InGaAs surfaces could be observed, which were dependent on the heating temperature under pure hydrogen. The arsenic-rich InGaAs surface was observed for temperatures less than 300 C and showed in the LEED picture a (4 x 3) reconstruction. In the temperature range from 300 C until about 500 C a (2 x 4) reconstruction was observed, above 500 C the InGaAs surface 94 x 2)/c(8 x 2) was reconstructed. Subsequently the study of the growth of thin GaAsSb layers on these three InGaAs surface reconstructions followed. XPS measurements showed that the Sb/As ratio in GaAsSb at the growth on the As-rich (4 x 3) reconstructed surface in the first monolayers was too low. The preparation of the GaAsSb on the two other InGaAs surfaces yielded however in both cases a distinctly higher Sb/As ratio. Finally tandem solar cells with differently

  4. Interface-related switching behaviors of amorphous Pr0.67Sr0.33MnO3-based memory cells

    Institute of Scientific and Technical Information of China (English)

    Zhang Ting; Bai Ying; Jia Cai-Hong; Zhang Wei-Feng

    2012-01-01

    The resistive switching properties in amorphous Pr0.67Sr0.33MnO3 films deposited by pulsed laser deposition are investigated. Reproducible and bipolar counter-8-shape and 8-shape switching behaviours of Au/Pr0.67Sr0.33MnOa/F:SnO2 junctions are obtained at room temperature. Dramatically,the coexistence of two switching polarities could be reversibly adjusted by an applied voltage range.The results allocated those two switching types to areas of different defect densities beneath the same electrode.The migration of oxygen vacancies and the trapping effect of electrons under an applied electric field play an important role.An interface-effect-related resistance switching is proposed in an amorphous Pr0.67Sr0.33MnO3-based memory cell.

  5. Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells

    Science.gov (United States)

    Hassen, Diab; El-Safty, Sherif A.; Tsuchiya, Koichi; Chatterjee, Abhijit; Elmarakbi, Ahmed; Shenashen, Mohamed. A.; Sakai, Masaru

    2016-04-01

    Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes.

  6. Interface-related switching behaviors of amorphous Pr0.67Sr0.33MnO3-based memory cells

    International Nuclear Information System (INIS)

    The resistive switching properties in amorphous Pr0.67Sr0.33MnO3 films deposited by pulsed laser deposition are investigated. Reproducible and bipolar counter-8-shape and 8-shape switching behaviours of Au/Pr0.67Sr0.33MnO3/F:SnO2 junctions are obtained at room temperature. Dramatically, the coexistence of two switching polarities could be reversibly adjusted by an applied voltage range. The results allocated those two switching types to areas of different defect densities beneath the same electrode. The migration of oxygen vacancies and the trapping effect of electrons under an applied electric field play an important role. An interface-effect-related resistance switching is proposed in an amorphous Pr0.67Sr0.33MnO3-based memory cell

  7. Electronic structure of the Zn(O,S)/Cu(In,Ga)Se2 thin-film solar cell interface

    Energy Technology Data Exchange (ETDEWEB)

    Mezher, Michelle [Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), Las Vegas NV 89154 USA; Garris, Rebekah [National Renewable Energy Laboratory (NREL), Golden CO 80401 USA; Mansfield, Lorelle M. [National Renewable Energy Laboratory (NREL), Golden CO 80401 USA; Horsley, Kimberly [Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), Las Vegas NV 89154 USA; Weinhardt, Lothar [Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), Las Vegas NV 89154 USA; Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen Germany; ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen Germany; Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe Germany; Duncan, Douglas A. [Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), Las Vegas NV 89154 USA; Blum, Monika [Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), Las Vegas NV 89154 USA; Rosenberg, Samantha G. [Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), Las Vegas NV 89154 USA; Bär, Marcus [Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), Las Vegas NV 89154 USA; Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 14109 Berlin Germany; Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus-Senftenberg, 03046 Cottbus Germany; Ramanathan, Kannan [National Renewable Energy Laboratory (NREL), Golden CO 80401 USA; Heske, Clemens [Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), Las Vegas NV 89154 USA; Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen Germany; ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen Germany; Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe Germany

    2016-03-10

    The electronic band alignment of the Zn(O,S)/Cu(In,Ga)Se2 interface in high-efficiency thin-film solar cells was derived using X-ray photoelectron spectroscopy, ultra-violet photoelectron spectroscopy, and inverse photoemission spectroscopy. Similar to the CdS/Cu(In,Ga)Se2 system, we find an essentially flat (small-spike) conduction band alignment (here: a conduction band offset of (0.09 +/- 0.20) eV), allowing for largely unimpeded electron transfer and forming a likely basis for the success of high-efficiency Zn(O,S)-based chalcopyrite devices. Furthermore, we find evidence for multiple bonding environments of Zn and O in the Zn(O,S) film, including ZnO, ZnS, Zn(OH)2, and possibly ZnSe.

  8. Reduced interface recombination in Cu2ZnSnS4 solar cells with atomic layer deposition Zn1-xSnxOy buffer layers

    Science.gov (United States)

    Platzer-Björkman, C.; Frisk, C.; Larsen, J. K.; Ericson, T.; Li, S.-Y.; Scragg, J. J. S.; Keller, J.; Larsson, F.; Törndahl, T.

    2015-12-01

    Cu2ZnSnS4 (CZTS) solar cells typically include a CdS buffer layer in between the CZTS and ZnO front contact. For sulfide CZTS, with a bandgap around 1.5 eV, the band alignment between CZTS and CdS is not ideal ("cliff-like"), which enhances interface recombination. In this work, we show how a Zn1-xSnxOy (ZTO) buffer layer can replace CdS, resulting in improved open circuit voltages (Voc) for CZTS devices. The ZTO is deposited by atomic layer deposition (ALD), with a process previously developed for Cu(In,Ga)Se2 solar cells. By varying the ALD process temperature, the position of the conduction band minimum of the ZTO is varied in relation to that of CZTS. A ZTO process at 95 °C is found to give higher Voc and efficiency as compared with the CdS reference devices. For a ZTO process at 120 °C, where the conduction band alignment is expected to be the same as for CdS, the Voc and efficiency is similar to the CdS reference. Further increase in conduction band minimum by lowering the deposition temperature to 80 °C shows blocking of forward current and reduced fill factor, consistent with barrier formation at the junction. Temperature-dependent current voltage analysis gives an activation energy for recombination of 1.36 eV for the best ZTO device compared with 0.98 eV for CdS. We argue that the Voc of the best ZTO devices is limited by bulk recombination, in agreement with a room temperature photoluminescence peak at around 1.3 eV for both devices, while the CdS device is limited by interface recombination.

  9. Optical chirality of protonated tetraphenylporphyrin J-aggregate formed at the liquid-liquid interface in a centrifugal liquid membrane cell

    International Nuclear Information System (INIS)

    J-aggregation of an achiral hydrophobic porphyrin, 5,10,15,20-tetraphenylporphyrin (H2TPP), at a toluene-4 M sulfuric acid interface was studied by a centrifugal liquid membrane-circular dichroism (CLM-CD) method. It was found for the first time that the exciton chirality sign of the interfacial J-aggregate of H4TPP2+ was affected by the rotational direction of the cylindrical CLM cell: a negative sign for clockwise (CW) rotation and a positive sign for anticlockwise (ACW) rotation. The sign of the measured optical chirality also depended on the injection position of the H2TPP stock solution in the rotating cell. Furthermore, it was observed that the rotational linear velocity of the aqueous phase was faster than that of the toluene phase, when the CLM cell was rotated at 7000 rpm. The effects of rotational direction and sample injection position on the optical chirality were overcome by the effect of chiral counter-ions such as (+)- or (-)-camphorsulfonic anions. From the observed results, a possible mechanism for the generation of the optical chirality of the interfacial J-aggregate was proposed taking into account an interfacial shear force and the spreading direction of H2TPP in the toluene phase

  10. 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.

  11. Are there generic mechanisms governing interactions between nanoparticles and cells? Epitope mapping the outer layer of the protein material interface

    Science.gov (United States)

    Lynch, Iseult

    2007-01-01

    In this paper we discuss the possibility of a general paradigm for cell-biomaterial and cell-nanoparticle interactions. The basis of the paradigm is that the nature of the biomaterial or nanoparticle surface is not the important parameter, but rather the nature of the outermost layer of adsorbed proteins as well as long-lived misfolded proteins shed from the surfaces. If the adsorbed protein is irreversibly adsorbed onto the surface it may be sufficiently disrupted so that a variety of peptide units (here termed “cryptic epitopes”) not usually expressed in nature at the surface of the protein become exposed. Similarly, where there is a slow exchange time with the surface, surface-induced perturbations may lead to long-lived misfolded proteins being shed from the surface and continuing to express altered surface peptide sequences. In cases where the proteins have lost most of their tertiary structure, anomalous peptide sequences and geometries that are not displayed at the surface by the native protein may in fact be presented after surface adsorption of a protein. Such anomalous surface expressions could contain novel epitopes that trigger various signalling pathways or even diseases. Thus, future approaches to understanding cell-biomaterial and cell-nanoparticle interactions should focus on characterising the outer layer of the adsorbed proteins, or “epitope mapping” as well as examining the possibility of formation of essentially “new” proteins as a result of desorption of conformationally or geometrically altered proteins.

  12. Testing Interfaces

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Henriksen, Mogens; Nilson, Jesper K.;

    1999-01-01

    the insulation and eventually cause breakdown.It is difficult to make a model of the real-life components that can be used to examine all of these phenomena. Some decisions have to be made on how to approach this problem, how to design a test cell and how the tests should be carried out. In this paper......, four suggestions on test cells are considered....

  13. Testing Interfaces

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Henriksen, Mogens; Nilson, Jesper K.;

    1999-01-01

    , destroy the insulation and eventually cause breakdown. It is difficult to make a model of the real-life components that can be used to examine all of these phenomena. Some decisions have to be made on how to approach this problem, how to design a test cell and how the tests should be carried out. In this...... paper, four suggestions on test cells are considered....

  14. The Ni-YSZ interface

    DEFF Research Database (Denmark)

    Jensen, Karin Vels

    The anode/electrolyte interface in solid oxide fuel cells (SOFC) is known to cause electrical losses. Geometrically simple Ni/yttria-stabilised zirconia (YSZ) interfaces were examined to gain information on the structural and chemical changes occurring during experiments at 1000°C in an atmosphere...... content (99.8% Ni and 99.995% Ni) were used to examine the impact of impurities on the polarisation resistance and contact area morphology. The electropolished nickel wires were pressed against a polished 8 mol% YSZ surface. Extensive structural changes from a flat interface to a hill and valley structure...

  15. Plasticity of airway epithelial cell transcriptome in response to flagellin.

    Directory of Open Access Journals (Sweden)

    Joan G Clark

    Full Text Available Airway epithelial cells (AEC are critical components of the inflammatory and immune response during exposure to pathogens. AECs in monolayer culture and differentiated epithelial cells in air-liquid interface (ALI represent two distinct and commonly used in vitro models, yet differences in their response to pathogens have not been investigated. In this study, we compared the transcriptional effects of flagellin on AECs in monolayer culture versus ALI culture using whole-genome microarrays and RNA sequencing. We exposed monolayer and ALI AEC cultures to flagellin in vitro and analyzed the transcriptional response by microarray and RNA-sequencing. ELISA and RT-PCR were used to validate changes in select candidates. We found that AECs cultured in monolayer and ALI have strikingly different transcriptional states at baseline. When challenged with flagellin, monolayer AEC cultures greatly increased transcription of numerous genes mapping to wounding response, immunity and inflammatory response. In contrast, AECs in ALI culture had an unexpectedly muted response to flagellin, both in number of genes expressed and relative enrichment of inflammatory and immune pathways. We conclude that in vitro culturing methods have a dramatic effect on the transcriptional profile of AECs at baseline and after stimulation with flagellin. These differences suggest that epithelial responses to pathogen challenges are distinctly different in culture models of intact and injured epithelium.

  16. Plasticity of airway epithelial cell transcriptome in response to flagellin.

    Science.gov (United States)

    Clark, Joan G; Kim, Kyoung-Hee; Basom, Ryan S; Gharib, Sina A

    2015-01-01

    Airway epithelial cells (AEC) are critical components of the inflammatory and immune response during exposure to pathogens. AECs in monolayer culture and differentiated epithelial cells in air-liquid interface (ALI) represent two distinct and commonly used in vitro models, yet differences in their response to pathogens have not been investigated. In this study, we compared the transcriptional effects of flagellin on AECs in monolayer culture versus ALI culture using whole-genome microarrays and RNA sequencing. We exposed monolayer and ALI AEC cultures to flagellin in vitro and analyzed the transcriptional response by microarray and RNA-sequencing. ELISA and RT-PCR were used to validate changes in select candidates. We found that AECs cultured in monolayer and ALI have strikingly different transcriptional states at baseline. When challenged with flagellin, monolayer AEC cultures greatly increased transcription of numerous genes mapping to wounding response, immunity and inflammatory response. In contrast, AECs in ALI culture had an unexpectedly muted response to flagellin, both in number of genes expressed and relative enrichment of inflammatory and immune pathways. We conclude that in vitro culturing methods have a dramatic effect on the transcriptional profile of AECs at baseline and after stimulation with flagellin. These differences suggest that epithelial responses to pathogen challenges are distinctly different in culture models of intact and injured epithelium. PMID:25668187

  17. THE INVESTIGATION ON INTERFACE CHARACTERISTIC OF CERAMIC SEALANTS PRODUCED FROM NATURAL ROCKS FOR SOLID OXIDE FUEL CELLS

    OpenAIRE

    Çiçekli, A Elif; ERCENK, Ediz; Yılmaz, Şenol

    2015-01-01

    Solid oxide fuel cells (SOFC), which are green electrochemical devices, transform directly chemical energy of fuel to electricity, and striking heat energy by using solid fuels as electrolyte [1-3].One of the essential problems for SOFC is to mix the gases, which used in anode and cathode, reacting electrochemically at high temperature before the reaction and/or the gas infiltration to outside of SOFC. It makes security problem and low efficiency. To use safe sealing material for SOFC is very...

  18. Endotoxemia-induced cytokine-mediated responses of hippocampal astrocytes transmitted by cells of the brain–immune interface

    OpenAIRE

    Hasegawa-Ishii, Sanae; Inaba, Muneo; Umegaki, Hiroyuki; Unno, Keiko; Wakabayashi, Keiji; Shimada, Atsuyoshi

    2016-01-01

    Systemic inflammation shifts the brain microenvironment towards a proinflammatory state. However, how peripheral inflammation mediates changes in the brain remains to be clarified. We aimed to identify hippocampal cells and cytokines that respond to endotoxemia. Mice were intraperitoneally injected with lipopolysaccharide (LPS) or saline, and examined 1, 4, and 24 h after injection. Tissue cytokine concentrations in the spleens and hippocampi were determined by multiplex assays. Another group...

  19. Interface-designed Membranes with Shape-controlled Patterns for High-performance Polymer Electrolyte Membrane Fuel Cells

    OpenAIRE

    Yukwon Jeon; Dong Jun Kim; Jong Kwan Koh; Yunseong Ji; Jong Hak Kim; Yong-Gun Shul

    2015-01-01

    Polymer electrolyte membrane fuel cell is a promising zero-emission power generator for stationary/automotive applications. However, key issues, such as performance and costs, are still remained for an economical commercialization. Here, we fabricated a high-performance membrane electrode assembly (MEA) using an interfacial design based on well-arrayed micro-patterned membranes including circles, squares and hexagons with different sizes, which are produced by a facile elastomeric mold method...

  20. Anodization parameters influencing the morphology and electrical properties of TiO2 nanotubes for living cell interfacing and investigations.

    Science.gov (United States)

    Khudhair, D; Bhatti, A; Li, Y; Hamedani, H Amani; Garmestani, H; Hodgson, P; Nahavandi, S

    2016-02-01

    Nanotube structures have attracted tremendous attention in recent years in many applications. Among such nanotube structures, titania nanotubes (TiO2) have received paramount attention in the medical domain due to their unique properties, represented by high corrosion resistance, good mechanical properties, high specific surface area, as well as great cell proliferation, adhesion and mineralization. Although lot of research has been reported in developing optimized titanium nanotube structures for different medical applications, however there is a lack of unified literature source that could provide information about the key parameters and experimental conditions required to develop such optimized structure. This paper addresses this gap, by focussing on the fabrication of TiO2 nanotubes through anodization process on both pure titanium and titanium alloys substrates to exploit the biocompatibility and electrical conductivity aspects, critical factors for many medical applications from implants to in-vivo and in-vitro living cell studies. It is shown that the morphology of TiO2 directly impacts the biocompatibility aspects of the titanium in terms of cell proliferation, adhesion and mineralization. Similarly, TiO2 nanotube wall thickness of 30-40nm has shown to exhibit improved electrical behaviour, a critical factor in brain mapping and behaviour investigations if such nanotubes are employed as micro-nano-electrodes. PMID:26652471

  1. Expression of polycomb protein BMI-1 maintains the plasticity of basal bronchial epithelial cells.

    Science.gov (United States)

    Torr, Elizabeth; Heath, Meg; Mee, Maureen; Shaw, Dominick; Sharp, Tyson V; Sayers, Ian

    2016-08-01

    The airway epithelium is altered in respiratory disease and is thought to contribute to disease etiology. A caveat to disease research is that the technique of isolation of bronchial epithelial cells from patients is invasive and cells have a limited lifespan. The aim of this study was to extensively characterize the plasticity of primary human bronchial epithelial cells that have been engineered to delay cell senescence including the ability of these cells to differentiate. Cells were engineered to express BMI-1 or hTERT using viral vector systems. Cells were characterized at passage (p) early (p5), mid (p10), and late (p15) stage for: BMI-1, p16, and CK14 protein expression, viability and the ability to differentiate at air-liquid interface (ALI), using a range of techniques including immunohistochemistry (IHC), immunofluorescence (IF), transepithelial electrical resistance (TEER), scanning electron microscopy (SEM), MUC5AC and beta tubulin (BTUB) staining. BMI-1-expressing cells maintained elevated levels of the BMI-1 protein and the epithelial marker CK14 and showed a suppression of p16. BMI-1-expressing cells had a viability advantage, differentiated at ALI, and had a normal karyotype. In contrast, hTERT-expressing cells had a reduced viability, showed limited differentiation, and had an abnormal karyotype. We therefore provide extensive characterization of the plasticity of BMI-1 expressing cells in the context of the ALI model. These cells retain properties of wild-type cells and may be useful to characterize respiratory disease mechanisms in vitro over sustained periods. PMID:27558999

  2. Interfaces habladas

    Directory of Open Access Journals (Sweden)

    María Teresa Soto Sanfiel

    2012-04-01

    Full Text Available Este artículo describe y piensa al fenómeno de las Interfaces habladas (IH desde variados puntos de vista y niveles de análisis. El texto se ha concebido con los objetivos específicos de: 1.- procurar una visión panorámica de aspectos de la producción y consumo comunicativo de las IH; 2.- ofrecer recomendaciones para su creación y uso eficaz, y 3.- llamar la atención sobre su proliferación e inspirar su estudio desde la comunicación. A pesar de la creciente presencia de las IF en nues-tras vidas cotidianas, hay ausencia de textos que las caractericen y analicen por sus aspectos comunicativos. El trabajo es pertinente porque el fenómeno significa un cambio respecto a estadios comunica-tivos precedentes con consecuencias en las concepciones intelectuales y emocionales de los usuarios. La proliferación de IH nos abre a nue-vas realidades comunicativas: hablamos con máquinas.

  3. Lipoxin A4 prevents tight junction disruption and delays the colonization of cystic fibrosis bronchial epithelial cells by Pseudomonas aeruginosa.

    Science.gov (United States)

    Higgins, Gerard; Fustero Torre, Coral; Tyrrell, Jean; McNally, Paul; Harvey, Brian J; Urbach, Valerie

    2016-06-01

    The specialized proresolution lipid mediator lipoxin A4 (LXA4) is abnormally produced in cystic fibrosis (CF) airways. LXA4 increases the CF airway surface liquid height and stimulates airway epithelial repair and tight junction formation. We report here a protective effect of LXA4 (1 nM) against tight junction disruption caused by Pseudomonas aeruginosa bacterial challenge together with a delaying action against bacterial invasion in CF airway epithelial cells from patients with CF and immortalized cell lines. Bacterial invasion and tight junction integrity were measured by gentamicin exclusion assays and confocal fluorescence microscopy in non-CF (NuLi-1) and CF (CuFi-1) bronchial epithelial cell lines and in primary CF cultures, grown under an air/liquid interface, exposed to either a clinical or laboratory strains of P. aeruginosa LXA4 delayed P. aeruginosa invasion and transepithelial migration in CF and normal bronchial epithelial cell cultures. These protective effects of LXA4 were inhibited by the ALX/FPR2 lipoxin receptor antagonist BOC-2. LXA4 prevented the reduction in mRNA biosynthesis and protein abundance of the tight junction protein ZO-1 and reduced tight junction disruption induced by P. aeruginsosa inoculation. In conclusion, LXA4 plays a protective role in bronchial epithelium by stimulating tight junction repair and by delaying and reducing the invasion of CF bronchial epithelial cells by P. aeruginsosa. PMID:27084849

  4. Structure and interface chemistry of MoO{sub 3} back contacts in Cu(In,Ga)Se{sub 2} thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Simchi, Hamed; Shafarman, William N. [Institute of Energy Conversion, University of Delaware, Newark, Delaware 19716 (United States); Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716 (United States); McCandless, Brian E.; Meng, T. [Institute of Energy Conversion, University of Delaware, Newark, Delaware 19716 (United States)

    2014-01-21

    Molybdenum oxide (MoO{sub 3}) is considered as a possible primary back contact for Cu(InGa)Se{sub 2} thin film solar cells for its potential as a transparent back contact for superstrate and bifacial devices. MoO{sub 3} films were deposited on Mo or ITO-coated soda lime glass substrates by reactive rf sputtering in an ambient of Ar + O{sub 2} with O{sub 2}/(O{sub 2} + Ar) = 35% on which Cu(In{sub 0.7}Ga{sub 0.3})Se{sub 2} alloy absorber layers were deposited using multi-source elemental evaporation. Scanning Electron Microscopy studies showed uniform coverage of the as-deposited MoO{sub 3} layer and good adhesion was obtained in all cases. X-ray Photoelectron Spectroscopy depth profile analysis showed that MoSe{sub 2} was not formed at the Cu(InGa)Se{sub 2} interface with either the Mo-MoO{sub 3} or ITO-MoO{sub 3} back contacts. Determination of the valence band offsets showed that the MoO{sub 3} layer at the interface changes the energy band alignment with Cu(InGa)Se{sub 2}, producing a primary contact with lower valence band offset than ITO. Cu(In,Ga)Se{sub 2} thin film solar cells prepared using an as-deposited Mo-MoO{sub 3} back contact yielded a best conversion efficiency of 14%, with V{sub OC} = 647 mV, J{sub SC} = 28.4 mA/cm{sup 2}, and FF = 78.1%. Cells with ITO-MoO{sub 3} back contact showed a best efficiency of 12%, with V{sub OC} = 642 mV, J{sub SC} = 26.8 mA/cm{sup 2}, and FF = 69.2%.

  5. Exciton-Dissociation and Charge-Recombination Processes in Pentacene/C 60 Solar Cells: Theoretical Insight into the Impact of Interface Geometry

    KAUST Repository

    Yi, Yuanping

    2009-11-04

    The exciton-dissociation and charge-recombination processes in organic solar cells based on pentacene/C60 heterojunctions are investigated by means of quantum-mechanical calculations. The electronic couplings and the rates of exciton dissociation and charge recombination have been evaluated for several geometrical configurations of the pentacene/C60 complex, which are relevant to bilayer and bulk heterojunctions. The results suggest that, irrespective of the actual pentacene-fullerene orientation, both pentacene-based and C60-based excitons are able to dissociate efficiently. Also, in the case of parallel configurations of the molecules at the pentacene/C60 interface, the decay of the lowest charge-transfer state to the ground state is calculated to be very fast; as a result, it can compete with the dissociation process into mobile charge carriers. Since parallel configurations are expected to be found more frequently in bulk heterojunctions than in bilayer heterojunctions, the performance of pentacene/C60 bulk-heterojunction solar cells is likely to be more affected by charge recombination than that of bilayer devices. © 2009 American Chemical Society.

  6. Nanoscale characterization of the electrical properties of oxide electrodes at the organic semiconductor-oxide electrode interface in organic solar cells

    Science.gov (United States)

    MacDonald, Gordon Alex

    This dissertation focuses on characterizing the nanoscale and surface averaged electrical properties of transparent conducting oxide electrodes such as indium tin oxide (ITO) and transparent metal-oxide (MO) electron selective interlayers (ESLs), such as zinc oxide (ZnO), the ability of these materials to rapidly extract photogenerated charges from organic semiconductors (OSCs) used in organic photovoltaic (OPV) cells, and evaluating their impact on the power conversion efficiency (PCE) of OPV devices. In Chapter 1, we will introduce the fundamental principles, benefits, and the key innovations that have advanced this technology. In Chapter 2 of this dissertation, we demonstrate an innovative application of conductive probe atomic force microscopy (CAFM) to map the nanoscale electrical heterogeneity at the interface between ITO, and a well-studied OSC, copper phthalocyanine (CuPc).(MacDonald et al. (2012) ACS Nano, 6, p. 9623) In this work we collected arrays of current-voltage (J-V) curves, using a CAFM probe as the top contact of CuPc/ITO systems, to map the local J-V responses. By comparing J-V responses to known models for charge transport, we were able to determine if the local rate-limiting-step for charge transport is through the OSC (ohmic) or the CuPc/ITO interface (non-ohmic). Chapter 3 focus on the electrical property characterization of RF-magnetron sputtered ZnO (sp-ZnO) ESL films on ITO substrates. We have shown that the energetic alignment of ESLs and the OSC active materials plays a critical role in determining the PCE of OPV devices and UV light soaking sensitivity. We have used a combination of device testing, modeling, and impedance spectroscopy to characterize the effects that energetic alignment has on the charge carrier transport and distribution within the OPV device. In Chapter 4 we demonstrate that the local properties of sp-ZnO films varies as a function of the underlying ITO crystal face. We show that the local ITO crystal face determines

  7. The ER to Golgi interface is the major concentration site of secretory proteins in the exocrine pancreatic cell.

    Science.gov (United States)

    Oprins, A; Rabouille, C; Posthuma, G; Klumperman, J; Geuze, H J; Slot, J W

    2001-11-01

    By using quantitative immuno-electron microscopy of two-sided labeled resin sections of rat exocrine pancreatic cells, we have established the relative concentrations of the secretory proteins amylase and chymotrypsinogen in the compartments of the secretory pathway. Their total concentration over the entire pathway was approximately 11 and approximately 460 times, respectively. Both proteins exhibited their largest increase in concentration between the endoplasmic reticulum and cis-Golgi, where they were concentrated 3-4 and 50-70 times, respectively. Over the further pathway, increases in concentration were moderate, albeit two times higher for chymotrypsinogen than for amylase. From trans-Golgi to secretory granules, where the main secretory protein concentration is often thought to occur, relatively small concentration increases were observed. Additional observations on a third secretory protein, procarboxypeptidase A, showed a concentration profile very similar to chymotrypsinogen. The relatively high concentration of amylase in the early compartments of the secretory route is consistent with its exceptionally slow intracellular transport. Our data demonstrate that secretory proteins undergo their main concentration between the endoplasmic reticulum and cis-Golgi, where we have previously found concentration activity associated with vesicular tubular clusters (Martínez-Menárguez JA, Geuze HJ, Slot JW, Klumperman J. Cell 1999; 98: 81-90). PMID:11733050

  8. Differentiation of porcine mesenchymal stem cells into epithelial cells as a potential therapeutic application to facilitate epithelial regeneration.

    Science.gov (United States)

    Kokubun, Kelsey; Pankajakshan, Divya; Kim, Min-Jung; Agrawal, Devendra K

    2016-02-01

    Epithelial denudation is one of the characteristics of chronic asthma. To restore its functions, the airway epithelium has to rapidly repair the injuries and regenerate its structure and integrity. Mesenchymal stem cells (MSCs) have the ability to differentiate into many cell lineages. However, the differentiation of MSCs into epithelial cells has not been fully studied. Here, we examined the differentiation of MSCs into epithelial cells using three different media compositions with various growth supplementations. The MSCs were isolated from porcine bone marrow by density gradient centrifugation. The isolated MSCs were CD11(-) CD34(-) CD45(-) CD44(+) CD90(+) and CD105(+) by immunostaining and flow cytometry. MSCs were stimulated with EpiGRO (Millipore), BEpiCM (ScienCell) and AECGM (PromoCell) media for 5 and 10 days, and epithelial differentiation was assessed by qPCR (keratin 14, 18 and EpCAM), fluorometry (cytokeratin 7-8, cytokeratin 14-15-16-19 and EpCAM), western blot analysis (pancytokeratin, EpCAM) and flow cytometry (cytokeratin 7-8, cytokeratin 14-15-16-19 and EpCAM). The functional marker MUC1 was also assessed after 10 days of air-liquid interface (ALI) culture in optimized media. Cells cultured in BEpiCM containing fibroblast growth factor and prostaglandin E2 showed the highest expression of the epithelial markers: CK7-8 (85.90%); CK-14-15-16-19 (10.14%); and EpCAM (64.61%). The cells also expressed functional marker MUC1 after ALI culture. The differentiated MSCs when cultured in BEpiCM medium ex vivo in a bioreactor on a decellularized trachea for 10 days retained the epithelial-like phenotype. In conclusion, porcine bone marrow-derived MSCs demonstrate commitment to the epithelial lineage and might be a potential therapy for facilitating the repair of denuded airway epithelium. PMID:23696537

  9. Exploring the heterogeneous interfaces in organic or ruthenium dye-sensitized liquid- and solid-state solar cells.

    Science.gov (United States)

    Kwon, Young Soo; Song, Inwoo; Lim, Jong Chul; Song, In Young; Siva, Ayyanar; Park, Taiho

    2012-06-27

    The interfacial properties were systematically investigated using an organic sensitizer (3-(5'-{4-[(4-tert-butyl-phenyl)-p-tolyl-amino]-phenyl}-[2,2']bithiophenyl-5-yl)-2-cyano-acrylic acid (D)) and inorganic sensitizer (bis(tetrabutylammonium) cis-bis(thiocyanato)bis(2,2'-bipyridine-4,4'-dicarboxylato) ruthenium(II) (N719)) in a liquid-state and a solid-state dye-sensitized solar cell (DSC). For liquid-DSCs, the faster charge recombination for the surface of D-sensitized TiO2 resulted in shorter diffusion length (LD) of ∼3.9 μm than that of N719 (∼7.5 μm), limiting the solar cell performance at thicker films used in liquid-DSCs. On the other hand, for solid-DSCs using thin TiO2 films (∼ 2 μm), D-sensitized device outperforms the N719-sensitized device in an identical fabrication condition, mainly due to less perfect wetting ability of solid hole conductor into the porous TiO2 network, inducing the dye monolayer act as an insulation layer, while liquid electrolyte is able to fully wet the surface of TiO2. Such insulation effect was attributed to the fact that the significant increase in recombination resistance (from 865 to 4,400 Ω/cm(2)) but shorter electron lifetime (from 10.8 to 0.8 ms) when compared to liquid-DSCs. Higher recombination resistance for solid-DSCs induced the electron transport-limited situation, showing poor performance of N719-sensitized device which has shorter electron transport time and similar LD (2.9 μm) with D-sensitized device (3.0 μm). PMID:22658859

  10. Active matter clusters at interfaces.

    Science.gov (United States)

    Copenhagen, Katherine; Gopinathan, Ajay

    2016-03-01

    Collective and directed motility or swarming is an emergent phenomenon displayed by many self-organized assemblies of active biological matter such as clusters of embryonic cells during tissue development, cancerous cells during tumor formation and metastasis, colonies of bacteria in a biofilm, or even flocks of birds and schools of fish at the macro-scale. Such clusters typically encounter very heterogeneous environments. What happens when a cluster encounters an interface between two different environments has implications for its function and fate. Here we study this problem by using a mathematical model of a cluster that treats it as a single cohesive unit that moves in two dimensions by exerting a force/torque per unit area whose magnitude depends on the nature of the local environment. We find that low speed (overdamped) clusters encountering an interface with a moderate difference in properties can lead to refraction or even total internal reflection of the cluster. For large speeds (underdamped), where inertia dominates, the clusters show more complex behaviors crossing the interface multiple times and deviating from the predictable refraction and reflection for the low velocity clusters. We then present an extreme limit of the model in the absence of rotational damping where clusters can become stuck spiraling along the interface or move in large circular trajectories after leaving the interface. Our results show a wide range of behaviors that occur when collectively moving active biological matter moves across interfaces and these insights can be used to control motion by patterning environments.

  11. Active matter clusters at interfaces.

    Directory of Open Access Journals (Sweden)

    Katherine eCopenhagen

    2016-03-01

    Full Text Available Collective and directed motility or swarming is an emergent phenomenon displayed by many self-organized assemblies of active biological matter such as clusters of embryonic cells during tissue development, cancerous cells during tumor formation and metastasis, colonies of bacteria in a biofilm, or even flocks of birds and schools of fish at the macro-scale. Such clusters typically encounter very heterogeneous environments. What happens when a cluster encounters an interface between two different environments has implications for its function and fate. Here we study this problem by using a mathematical model of a cluster that treats it as a single cohesive unit that moves in two dimensions by exerting a force/torque per unit area whose magnitude depends on the nature of the local environment. We find that low speed (overdamped clusters encountering an interface with a moderate difference in properties can lead to refraction or even total internal reflection of the cluster. For large speeds (underdamped, where inertia dominates, the clusters show more complex behaviors crossing the interface multiple times and deviating from the predictable refraction and reflection for the low velocity clusters. We then present an extreme limit of the model in the absence of rotational damping where clusters can become stuck spiraling along the interface or move in large circular trajectories after leaving the interface. Our results show a wide range of behaviors that occur when collectively moving active biological matter moves across interfaces and these insights can be used to control motion by patterning environments.

  12. Interface-designed Membranes with Shape-controlled Patterns for High-performance Polymer Electrolyte Membrane Fuel Cells

    Science.gov (United States)

    Jeon, Yukwon; Kim, Dong Jun; Koh, Jong Kwan; Ji, Yunseong; Kim, Jong Hak; Shul, Yong-Gun

    2015-11-01

    Polymer electrolyte membrane fuel cell is a promising zero-emission power generator for stationary/automotive applications. However, key issues, such as performance and costs, are still remained for an economical commercialization. Here, we fabricated a high-performance membrane electrode assembly (MEA) using an interfacial design based on well-arrayed micro-patterned membranes including circles, squares and hexagons with different sizes, which are produced by a facile elastomeric mold method. The best MEA performance is achieved using patterned Nafion membrane with a circle 2 μm in size, which exhibited a very high power density of 1906 mW/cm2 at 75 °C and Pt loading of 0.4 mg/cm2 with 73% improvement compared to the commercial membrane. The improved performance are attributed to the decreased MEA resistances and increased surface area for higher Pt utilization of over 80%. From these enhanced properties, it is possible to operate at lower Pt loading of 0.2 mg/cm2 with an outstanding performance of 1555 mW/cm2 and even at air/low humidity operations.

  13. Effect of guaifenesin on mucin production, rheology, and mucociliary transport in differentiated human airway epithelial cells.

    Science.gov (United States)

    Seagrave, JeanClare; Albrecht, Helmut; Park, Yong Sung; Rubin, Bruce; Solomon, Gail; Kim, K Chul

    2011-12-01

    Guaifenesin is widely used to alleviate symptoms of excessive mucus accumulation in the respiratory tract. However, its mechanism of action is poorly understood. The authors hypothesized that guaifenesin improves mucociliary clearance in humans by reducing mucin release, by decreasing mucus viscoelasticity, and by increasing mucociliary transport. To test these hypotheses, human differentiated airway epithelial cells, cultured at an air-liquid interface, were treated with clinically relevant concentrations of guaifenesin by addition to the basolateral medium. To evaluate the effect on mucin secretion, the authors used an anzyme-linked immunosorbent assay (ELISA) to measure the amounts of MUC5AC protein in apical surface fluid and cell lysates. To measure mucociliary transportability, additional cultures were treated for 1 or 6 hours with guaifenesin, and the movement of cell debris was measured from video data. Further, the authors measured mucus dynamic viscoelasticity using a micro cone and plate rheometer with nondestructive creep transformation. Guaifenesin suppressed mucin production in a dose-dependent manner at clinically relevant concentrations. The reduced mucin production was associated with increased mucociliary transport and decreased viscoelasticity of the mucus. Viability of the cultures was not significantly affected. These results suggest that guaifenesin could improve mucociliary clearance in humans by reducing the release and/or production of mucins, thereby altering mucus rheology. PMID:22044398

  14. Structural organization of liquid crystals at liquid crystal-air interface: Synchrotron X-ray reflectivity and computational simulations

    Science.gov (United States)

    Sadati, Monirosadat; Ramezani-Dakhel, Hadi; Bu, Wei; Sevgen, Emre; Liang, Zhu; Erol, Cem; Taheri Qazvini, Nader; Rahimi, Mohammad; Lin, Binhua; Roux, Benoit; Schlossman, Mark; de Pablo, Juan J.

    Numerous applications of liquid crystals (LC) rely on control of molecular orientation at an interface. However, little is known about the precise molecular structure of such interfaces. In this work, we have performed synchrotron X-ray reflectivity measurements accompanied by an advanced theoretical and computational analysis to study the structural organization of liquid crystals at the air-liquid crystal interface. The X-ray reflectivity was measured from two nematic (5CB) and smectic (8CB) liquid crystals at several temperatures, in the nematic phase and above the nematic-isotropic transition. Our computational simulations and X-ray reflectivity results indicate that in the case of 8CB nematic phase, incipient bulk smectic fluctuations are pinned at the interface to form temperature-dependent multilayers at the interface. Such layers can extend far from the interface. However, the interface of 5CB in the nematic phase exhibits a relatively small number of layers. These measurements will be extended to the study of the LC-aqueous electrolyte interfaces to understand the effects of electrostatic interactions and external stimuli on the interfacial anchoring energy and LC orientational ordering.

  15. Equivalent circuit representation of hysteresis in solar cells that considers interface charge accumulation: Potential cause of hysteresis in perovskite solar cells

    Science.gov (United States)

    Seki, Kazuhiko

    2016-07-01

    If charge carriers accumulate in the charge transport layer of a solar cell, then the transient response of the electric field that originates from these accumulated charges results in hysteresis in the current-voltage (J-V) characteristics. While this mechanism was previously known, a theoretical model to explain these J-V characteristics has not been considered to date. We derived an equivalent circuit from the proposed hysteresis mechanism. By solving the equivalent circuit model, we were able to reproduce some of the features of hysteresis in perovskite solar cells.

  16. Enhanced Oxygen and Hydroxide Transport in a Cathode Interface by Efficient Antibacterial Property of a Silver Nanoparticle-Modified, Activated Carbon Cathode in Microbial Fuel Cells.

    Science.gov (United States)

    Li, Da; Qu, Youpeng; Liu, Jia; Liu, Guohong; Zhang, Jie; Feng, Yujie

    2016-08-17

    A biofilm growing on an air cathode is responsible for the decreased performance of microbial fuel cells (MFCs). For the undesired biofilm to be minimized, silver nanoparticles were synthesized on activated carbon as the cathodic catalyst (Ag/AC) in MFCs. Ag/AC enhanced maximum power density by 14.6% compared to that of a bare activated carbon cathode (AC) due to the additional silver catalysis. After operating MFCs over five months, protein content on the Ag/AC cathode was only 38.3% of that on the AC cathode, which resulted in a higher oxygen concentration diffusing through the Ag/AC cathode. In addition, a lower pH increment (0.2 units) was obtained near the Ag/AC catalyst surface after biofouling compared to 0.8 units of the AC cathode, indicating that less biofilm on the Ag/AC cathode had a minor resistance on hydroxide transported from the catalyst layer interfaces to the bulk solution. Therefore, less decrements of the Ag/AC activity and MFC performance were obtained. This result indicated that accelerated transport of oxygen and hydroxide, benefitting from the antibacterial property of the cathode, could efficiently maintain higher cathode stability during long-term operation. PMID:27441786

  17. Study of surfaces and interfaces in CdS-Cu2S and (Cd sub(x) Zn sub(1-x))S-Cu2S solar cells

    International Nuclear Information System (INIS)

    Auger microprobe was used for the analysis of interfaces and surfaces in several stages involved in the preparation of solar cells, in order to study the origin of adhesion problems and to study the formation of CdS-Cu2S barrier by the wet method. The detachment of the first CdS and (Cd sub(x) Zn sub(1-x))S films, during the dip process, was attributed to the contamination of Cr-Ag metallic substrates by existing chlorine from the environment next to the sea, due to long film stocking, by degasified species from the evaporating material and by the ejection of particles together with CdS vapour during deposition. The formation of conical mounds on the surface and of the CdS-Cu2S barrier at aproximatelly 3000 A depth in the dipped samples were observed. The migration of copper towards surface direction and the formation of a superficial thin layer of copper oxide after treatment in H2 plasma and air heating, were also verified. (C.L.B.)

  18. Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells.

    Science.gov (United States)

    Hassen, Diab; El-Safty, Sherif A; Tsuchiya, Koichi; Chatterjee, Abhijit; Elmarakbi, Ahmed; Shenashen, Mohamed A; Sakai, Masaru

    2016-01-01

    Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes. PMID:27075551

  19. Revisiting a many-body model for water based on a single polarizable site: From gas phase clusters to liquid and air/liquid water systems

    Science.gov (United States)

    Réal, Florent; Vallet, Valérie; Flament, Jean-Pierre; Masella, Michel

    2013-09-01

    We present a revised version of the water many-body model TCPE [M. Masella and J.-P. Flament, J. Chem. Phys. 107, 9105 (1997)], which is based on a static three charge sites and a single polarizable site to model the molecular electrostatic properties of water, and on an anisotropic short range many-body energy term specially designed to accurately model hydrogen bonding in water. The parameters of the revised model, denoted TCPE/2013, are here developed to reproduce the ab initio energetic and geometrical properties of small water clusters (up to hexamers) and the repulsive water interactions occurring in cation first hydration shells. The model parameters have also been refined to reproduce two liquid water properties at ambient conditions, the density and the vaporization enthalpy. Thanks to its computational efficiency, the new model range of applicability was validated by performing simulations of liquid water over a wide range of temperatures and pressures, as well as by investigating water liquid/vapor interfaces over a large range of temperatures. It is shown to reproduce several important water properties at an accurate enough level of precision, such as the existence liquid water density maxima up to a pressure of 1000 atm, the water boiling temperature, the properties of the water critical point (temperature, pressure, and density), and the existence of a "singularity" temperature at about 225 K in the supercooled regime. This model appears thus to be particularly well-suited for characterizing ion hydration properties under different temperature and pressure conditions, as well as in different phases and interfaces.

  20. Equivalent circuit representation of hysteresis in solar cells that considers interface charge accumulation: Potential cause of hysteresis in perovskite solar cells

    OpenAIRE

    Seki, Kazuhiko

    2016-01-01

    If charge carriers accumulate in the charge transport layer of a solar cell, then the transient response of the electric field that originates from these accumulated charges results in hysteresis in the current-voltage ($J$-$V$) characteristics. While this mechanism was previously known, a theoretical model to explain these $J$-$V$ characteristics has not been considered to date. We derived an equivalent circuit from the proposed hysteresis mechanism. By solving the equivalent circuit model, ...

  1. Recent work on material interface reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Mosso, S.J.; Swartz, B.K. [Los Alamos National Lab., NM (United States)

    1997-12-31

    For the last 15 years, many Eulerian codes have relied on a series of piecewise linear interface reconstruction algorithms developed by David Youngs. In a typical Youngs` method, the material interfaces were reconstructed based upon nearly cell values of volume fractions of each material. The interfaces were locally represented by linear segments in two dimensions and by pieces of planes in three dimensions. The first step in such reconstruction was to locally approximate an interface normal. In Youngs` 3D method, a local gradient of a cell-volume-fraction function was estimated and taken to be the local interface normal. A linear interface was moved perpendicular to the now known normal until the mass behind it matched the material volume fraction for the cell in question. But for distorted or nonorthogonal meshes, the gradient normal estimate didn`t accurately match that of linear material interfaces. Moreover, curved material interfaces were also poorly represented. The authors will present some recent work in the computation of more accurate interface normals, without necessarily increasing stencil size. Their estimate of the normal is made using an iterative process that, given mass fractions for nearby cells of known but arbitrary variable density, converges in 3 or 4 passes in practice (and quadratically--like Newton`s method--in principle). The method reproduces a linear interface in both orthogonal and nonorthogonal meshes. The local linear approximation is generally 2nd-order accurate, with a 1st-order accurate normal for curved interfaces in both two and three dimensional polyhedral meshes. Recent work demonstrating the interface reconstruction for curved surfaces will /be discussed.

  2. Electronic structure of semiconductor interfaces

    International Nuclear Information System (INIS)

    The study of semiconductor interfaces is one of the most active and exciting areas of current semiconductor research. Because interfaces play a vital role in modern semiconductor technology (integrated circuits, heterojunction lasers, solar cells, infrared detectors, etc.), there is a strong incentive to understand interface properties at a fundamental level and advance existing technology thereby. At the same time, technological advances such as molecular beam epitaxy have paved the way for the fabrication of semiconductor heterojunctions and superlattices of novel design which exhibit unusual electronic, optical, and magnetic properties and offer unique opportunities for fundamental scientific research. A general perspective on this subject is offered treating such topics as the atomic and electronic structure of semiconductor surfaces and interfaces; oxidation and oxide layers; semiconductor heterojunctions and superlattices; rectifying metal-semiconductor contacts; and interface reactions. Recent progress is emphasized and some future directions are indicated. In addition, the role that large-scale scientific computation has played in furthering our theoretical understanding of semiconductor surfaces and interfaces is discussed. Finally, the nature of theoretical models, and the role they play in describing the physical world is considered. (Author)

  3. Modifying the organic/electrode interface in Organic Solar Cells (OSCs) and improving the efficiency of solution-processed phosphorescent Organic Light-Emitting Diodes (OLEDs)

    Science.gov (United States)

    Xiao, Teng

    Organic semiconductors devices, such as, organic solar cells (OSCs), organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs) have drawn increasing interest in recent decades. As organic materials are flexible, light weight, and potentially low-cost, organic semiconductor devices are considered to be an alternative to their inorganic counterparts. This dissertation will focus mainly on OSCs and OLEDs. As a clean and renewable energy source, the development of OSCs is very promising. Cells with 9.2% power conversion efficiency (PCE) were reported this year, compared to behavior of the devices are not satisfactory. All these limitations invoke the demand for new organic materials, improved device architectures, low-cost fabrication methods, and better understanding of device physics. For OSCs, we attempted to improve the PCE by modifying the interlayer between active layer/metal. We found that ethylene glycol (EG) treated poly(3,4-ethylenedioxy-thiophene):polystyrenesulfonate (PEDOT: PSS) improves hole collection at the metal/polymer interface, furthermore it also affects the growth of the poly(3-hexylthiophene) (P3HT):phenyl-C 61-butyric acid methyl ester (PCBM) blends, making the phase segregation more favorable for charge collection. We then studied organic/inorganic tandem cells. We also investigated the effect of a thin LiF layer on the hole-collection of copper phthalocyanine (CuPc)/C70-based small molecular OSCs. A thin LiF layer serves typically as the electron injection layer in OLEDs and electron collection interlayer in the OSCs. However, several reports showed that it can also assist in hole-injection in OLEDs. Here we first demonstrate that it assists hole-collection in OSCs, which is more obvious after air-plasma treatment, and explore this intriguing dual role. For OLEDs, we focus on solution processing methods to fabricate highly efficient phosphorescent OLEDs. First, we investigated OLEDs with a polymer host matrix, and

  4. Quantifying charge transfer energies at donor–acceptor interfaces in small-molecule solar cells with constrained DFTB and spectroscopic methods

    International Nuclear Information System (INIS)

    Charge transfer states around the donor–acceptor interface in an organic solar cell determine the device performance in terms of the open circuit voltage. In the present work, we propose a computational scheme based on constrained density functional tight binding theory (c-DFTB) to assess the energy of the lowest charge transfer (CT) state in such systems. A comparison of the c-DFTB scheme with Hartree–Fock based configuration interaction of singles (CIS) and with time-dependent density functional theory (TD-DFT) using the hybrid functional B3LYP reveals that CIS and c-DFTB reproduce the correct Coulomb asymptotics between cationic donor and anionic acceptor configurations, whereas TD-DFT gives a qualitatively wrong excitation energy. Together with an embedding scheme accounting for the polarizable medium, this c-DFTB scheme is applied to several donor–acceptor combinations used in molecular solar cells. The external quantum efficiency of photovoltaic cells based on zinc phthalocyanine–C60 blends reveals a CT band remaining much narrower than the density of states of acceptor HOMO and donor LUMO, an observation which can be interpreted in a natural way in terms of Marcus transfer theory. A detailed comparison with c-DFTB calculations reveals an energy difference of 0.32 eV between calculated and observed absorption from the electronic ground state into the CT state. In a blend of a functionalized thiophene and C60, the photoluminescence spectra differ significantly from neat films, allowing again an assignment to CT states. The proposed computational scheme reproduces the observed trends of the observed open circuit voltages in photovoltaic devices relying on several donor–acceptor blends, finding an offset of 1.16 eV on average. This value is similar as in polymer–fullerene photovoltaic systems where it amounts to about 0.9 eV, indicating that the photophysics of CT states in molecular donor–acceptor blends and in polymer–fullerene blends are

  5. Interface solutions for interface side effects?

    Directory of Open Access Journals (Sweden)

    Stoffregen Thomas A.

    2011-12-01

    Full Text Available Human-computer interfaces often give rise to a variety of side effects, including eyestrain, headache, fatigue, and motion sickness (aka cybersickness, simulator sickness. We might hope that improvements in interface design would tend to reduce these side effects. Unfortunately, history reveals just the opposite: The incidence and severity of motion sickness (for example is positively related to the progressive sophistication of display technology and systems. In this presentation, I enquire about the future of interface technologies in relation to side effects. I review the types of side effects that occur and what is known about the causes of interface side effects. I suggest new ways of understanding relations between interface technologies and side effects, and new ways to approach the problem of interface side effects.

  6. A new Pharmaceutical Aerosol Deposition Device on Cell Cultures (PADDOCC) to evaluate pulmonary drug absorption for metered dose dry powder formulations.

    Science.gov (United States)

    Hein, Stephanie; Bur, Michael; Schaefer, Ulrich F; Lehr, Claus-Michael

    2011-01-01

    Absorption studies with aerosol formulation delivered by metered dose inhalers across cell- and tissue-based in vitro models of the pulmonary epithelia are not trivial due to the complexity of the processes involved: (i) aerosol generation and deposition, (ii) drug release from the carrier, and (iii) absorption across the epithelial air-blood barrier. In contrast to the intestinal mucosa, pulmonary epithelia are only covered by a thin film of lining fluid. Submersed cell culture systems would not allow to studying the deposition of aerosol particles and their effects on this delicate epithelial tissue. We developed a new Pharmaceutical Aerosol Deposition Device on Cell Cultures (PADDOCC) to mimic the inhalation of a single metered aerosol dose and its subsequent deposition on filter-grown pulmonary epithelial cell monolayers exposed to an air-liquid interface. The reproducibility of deposition of these dry powder aerosols and subsequent drug transport across Calu-3 monolayers with commercially available dry powder inhalers containing salbutamol sulphate or budesonide could be demonstrated. In the context of developing new dry powder aerosol formulations, PADDOCC appears as a useful tool, allowing reducing animal testing and faster translation into clinical trials. PMID:20951200

  7. Changes in human Langerhans cells following intradermal injection of influenza virus-like particle vaccines.

    Directory of Open Access Journals (Sweden)

    Marc Pearton

    Full Text Available There is a significant gap in our fundamental understanding of early morphological and migratory changes in human Langerhans cells (LCs in response to vaccine stimulation. As the vast majority of LCs studies are conducted in small animal models, substantial interspecies variation in skin architecture and immunity must be considered when extrapolating the results to humans. This study aims to determine whether excised human skin, maintained viable in organ culture, provides a useful human model for measuring and understanding early immune response to intradermally delivered vaccine candidates. Excised human breast skin was maintained viable in air-liquid-interface organ culture. This model was used for the first time to show morphological changes in human LCs stimulated with influenza virus-like particle (VLP vaccines delivered via intradermal injection. Immunohistochemistry of epidermal sheets and skin sections showed that LCs in VLP treated skin lost their typical dendritic morphology. The cells were more dispersed throughout the epidermis, often in close proximity to the basement membrane, and appeared vertically elongated. Our data provides for increased understanding of the complex morphological, spatial and temporal changes that occur to permit LC migration through the densely packed keratinocytes of the epidermis following exposure to vaccine. Significantly, the data not only supports previous animal data but also provides new and essential evidence of host response to this vaccination strategy in the real human skin environment.

  8. Establishment of 3D organotypic cultures using human neonatal epidermal cells.

    Science.gov (United States)

    Gangatirkar, Pradnya; Paquet-Fifield, Sophie; Li, Amy; Rossi, Ralph; Kaur, Pritinder

    2007-01-01

    This protocol describes an ex vivo three-dimensional coculture system optimized to study the skin regenerative ability of primary human keratinocytes grown at the air-liquid interface on collagen matrices embedded with human dermal fibroblasts. An option for enrichment of keratinocyte stem cells and their progeny using fluorescence-activated cell sorting is also provided. Initially, dermal equivalents, comprising human passaged fibroblasts seeded in a collagen matrix, are grown on porous filters (3 mum) placed in transwells. After 1 week, primary human keratinocytes are seeded on this base. One week later, an air-lift transition is performed, leading to the differentiation of the keratinocytes, which are macroscopically visible as artificial skin after a couple of days. The cultures can be harvested 1 week after the air-lift and processed for immunohistochemistry or gene expression analysis. The overall procedure can be completed in 3 weeks, including the preparation of the dermal equivalent and the seeding of the primary keratinocytes. PMID:17401352

  9. FXYD1 negatively regulates Na(+)/K(+)-ATPase activity in lung alveolar epithelial cells.

    Science.gov (United States)

    Wujak, Łukasz A; Blume, Anna; Baloğlu, Emel; Wygrecka, Małgorzata; Wygowski, Jegor; Herold, Susanne; Mayer, Konstantin; Vadász, István; Besuch, Petra; Mairbäurl, Heimo; Seeger, Werner; Morty, Rory E

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is clinical syndrome characterized by decreased lung fluid reabsorption, causing alveolar edema. Defective alveolar ion transport undertaken in part by the Na(+)/K(+)-ATPase underlies this compromised fluid balance, although the molecular mechanisms at play are not understood. We describe here increased expression of FXYD1, FXYD3 and FXYD5, three regulatory subunits of the Na(+)/K(+)-ATPase, in the lungs of ARDS patients. Transforming growth factor (TGF)-β, a pathogenic mediator of ARDS, drove increased FXYD1 expression in A549 human lung alveolar epithelial cells, suggesting that pathogenic TGF-β signaling altered Na(+)/K(+)-ATPase activity in affected lungs. Lentivirus-mediated delivery of FXYD1 and FXYD3 allowed for overexpression of both regulatory subunits in polarized H441 cell monolayers on an air/liquid interface. FXYD1 but not FXYD3 overexpression inhibited amphotericin B-sensitive equivalent short-circuit current in Ussing chamber studies. Thus, we speculate that FXYD1 overexpression in ARDS patient lungs may limit Na(+)/K(+)-ATPase activity, and contribute to edema persistence. PMID:26410457

  10. Cellular response of mucociliary differentiated primary bronchial epithelial cells to diesel exhaust.

    Science.gov (United States)

    Zarcone, Maria C; Duistermaat, Evert; van Schadewijk, Annemarie; Jedynska, Aleksandra; Hiemstra, Pieter S; Kooter, Ingeborg M

    2016-07-01

    Diesel emissions are the main source of air pollution in urban areas, and diesel exposure is linked with substantial adverse health effects. In vitro diesel exposure models are considered a suitable tool for understanding these effects. Here we aimed to use a controlled in vitro exposure system to whole diesel exhaust to study the effect of whole diesel exhaust concentration and exposure duration on mucociliary differentiated human primary bronchial epithelial cells (PBEC). PBEC cultured at the air-liquid interface were exposed for 60 to 375 min to three different dilutions of diesel exhaust (DE). The DE mixture was generated by an engine at 47% load, and characterized for particulate matter size and distribution and chemical and gas composition. Cytotoxicity and epithelial barrier function was assessed, as well as mRNA expression and protein release analysis. DE caused a significant dose-dependent increase in expression of oxidative stress markers (HMOX1 and NQO1; n = 4) at 6 h after 150 min exposure. Furthermore, DE significantly increased the expression of the markers of the integrated stress response CHOP and GADD34 and of the proinflammatory chemokine CXCL8, as well as release of CXCL8 protein. Cytotoxic effects or effects on epithelial barrier function were observed only after prolonged exposures to the highest DE dose. These results demonstrate the suitability of our model and that exposure dose and duration and time of analysis postexposure are main determinants for the effects of DE on differentiated primary human airway epithelial cells. PMID:27190060

  11. Modification of photoelectrode with thiol-functionalized Calix[4]arenes as interface energy barrier for high efficiency in dye-sensitized solar cells

    Science.gov (United States)

    Akın, Seçkin; Gülen, Mahir; Sayın, Serkan; Azak, Hacer; Yıldız, Hüseyin Bekir; Sönmezoğlu, Savaş

    2016-03-01

    We successfully synthesize a series of bis-thiol-substituted calix[4]arene derivatives bearing diverse groups on the upper-rim/lower-rim (C@SH-1, C@SH-2, C@SH-3, C@SH-4, C@SH-5). For the first time, we apply these derivatives as interface modifiers for improving the photovoltaic response of a Ru-bipy dye (N-719)-sensitized TiO2 photoanode in dye-sensitized solar cells (DSSCs). We use FT-IR, H- and C-NMR, UV-vis spectrophotometry, and elemental analysis techniques to characterize the structures of the calix[4]arene derivatives. We achieve an overall photon-to-electron conversion efficiency (PCE) of 12.97% with the DSSCs based on 25,27-bis(5-thiol-1-oxypentane)-26,28-dihydroxycalix[4]arene (C@SH-3)-modified TiO2 photoanode (Jsc = 9.49 mA cm-2, Voc = 672 mV, FF = 61.1%) compared with a system of bare TiO2 (PCE: 6.82%) under AM 1.5G illumination of 300 W/m2. In addition, we also study the influence of the chain length (C@SH-2; with 3 carbons and C@SH-3; with 5 carbons) and subsidiary ligand groups such as alkyl (C@SH-1), nitro (C@SH-4), and amine (C@SH-5) on the surface morphology, spectral response, and photovoltaic performance. Our results reveal that the C@SH-3 calixarene is the best derivative for modifiying the TiO2 photoanode. Thiol-functionalized Calix[4]arene molecules play a role in assisting charge separation and preventing back recombination, which accounts for the observed enhancement in photovoltaic performance.

  12. Interface Simulation Distances

    Directory of Open Access Journals (Sweden)

    Pavol Černý

    2012-10-01

    Full Text Available The classical (boolean notion of refinement for behavioral interfaces of system components is the alternating refinement preorder. In this paper, we define a distance for interfaces, called interface simulation distance. It makes the alternating refinement preorder quantitative by, intuitively, tolerating errors (while counting them in the alternating simulation game. We show that the interface simulation distance satisfies the triangle inequality, that the distance between two interfaces does not increase under parallel composition with a third interface, and that the distance between two interfaces can be bounded from above and below by distances between abstractions of the two interfaces. We illustrate the framework, and the properties of the distances under composition of interfaces, with two case studies.

  13. Modifying the organic/electrode interface in Organic Solar Cells (OSCs) and improving the efficiency of solution-processed phosphorescent Organic Light-Emitting Diodes (OLEDs)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Teng [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    Organic semiconductors devices, such as, organic solar cells (OSCs), organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs) have drawn increasing interest in recent decades. As organic materials are flexible, light weight, and potentially low-cost, organic semiconductor devices are considered to be an alternative to their inorganic counterparts. This dissertation will focus mainly on OSCs and OLEDs. As a clean and renewable energy source, the development of OSCs is very promising. Cells with 9.2% power conversion efficiency (PCE) were reported this year, compared to < 8% two years ago. OSCs belong to the so-called third generation solar cells and are still under development. While OLEDs are a more mature and better studied field, with commercial products already launched in the market, there are still several key issues: (1) the cost of OSCs/OLEDs is still high, largely due to the costly manufacturing processes; (2) the efficiency of OSCs/OLEDs needs to be improved; (3) the lifetime of OSCs/OLEDs is not sufficient compared to their inorganic counterparts; (4) the physics models of the behavior of the devices are not satisfactory. All these limitations invoke the demand for new organic materials, improved device architectures, low-cost fabrication methods, and better understanding of device physics. For OSCs, we attempted to improve the PCE by modifying the interlayer between active layer/metal. We found that ethylene glycol (EG) treated poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT: PSS) improves hole collection at the metal/polymer interface, furthermore it also affects the growth of the poly(3- hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blends, making the phase segregation more favorable for charge collection. We then studied organic/inorganic tandem cells. We also investigated the effect of a thin LiF layer on the hole-collection of copper phthalocyanine (CuPc)/C70-based small molecular OSCs. A

  14. Interface localization near criticality

    CERN Document Server

    Delfino, Gesualdo

    2016-01-01

    The theory of interface localization in near-critical planar systems at phase coexistence is formulated from first principles. We show that mutual delocalization of two interfaces, amounting to interfacial wetting, occurs when the bulk correlation length critical exponent $\

  15. 柔性衬底非晶硅薄膜太阳电池界面处理的研究%Interface treatment of amorphous silicon thin film solar cells on flexible substrate

    Institute of Scientific and Technical Information of China (English)

    蔡宏琨; 陶科; 王林申; 赵敬芳; 隋妍萍; 张德贤

    2009-01-01

    The experiment and AMPS modeling have been used to analyze the characteristics of a-Si solar cells on flexible substrate with different buffer layers at the i/p interface. Combining with technology parameters, this paper uses different band gap and the defect density of states of the interface layer to simulate the characteristics of solar ceils. The modeling results show that the solar cells are deteriorated by the interface layer with a big band gap and large defect density of states. By optimizing treatment of i/p interface, the amorphous silicon solar cell on polyimide substrate has been achieved with an efficiency of 7.09%.%通过实验和模拟计算对比分析了i/p界面过渡层对太阳电池性能的影响.结合具体实验工艺参数,模拟计算了不同带隙和缺陷态密度的过渡层对太阳电池的影响,同时结合实验情况重现了宽带隙高缺陷态密度过渡层对太阳电池的损伤,为实验结果提供了理论依据.通过优化调整i/p界面过渡层的制备方法得到了转换效率为7.09%的聚酰亚胺衬底非晶硅薄膜太阳电池.

  16. Transcriptome sequencing reveals e-cigarette vapor and mainstream-smoke from tobacco cigarettes activate different gene expression profiles in human bronchial epithelial cells.

    Science.gov (United States)

    Shen, Yifei; Wolkowicz, Michael J; Kotova, Tatyana; Fan, Lonjiang; Timko, Michael P

    2016-01-01

    Electronic cigarettes (e-cigarettes) generate an aerosol vapor (e-vapor) thought to represent a less risky alternative to main stream smoke (MSS) of conventional tobacco cigarettes. RNA-seq analysis was used to examine the transcriptomes of differentiated human bronchial epithelial (HBE) cells exposed to air, MSS from 1R5F tobacco reference cigarettes, and e-vapor with and without added nicotine in an in vitro air-liquid interface model for cellular exposure. Our results indicate that while e-vapor does not elicit many of the cell toxicity responses observed in MSS-exposed HBE cells, e-vapor exposure is not benign, but elicits discrete transcriptomic signatures with and without added nicotine. Among the cellular pathways with the most significantly enriched gene expression following e-vapor exposure are the phospholipid and fatty acid triacylglycerol metabolism pathways. Our data suggest that alterations in cellular glycerophopholipid biosynthesis are an important consequences of e-vapor exposure. Moreover, the presence of nicotine in e-vapor elicits a cellular response distinct from e-vapor alone including alterations of cytochrome P450 function, retinoid metabolism, and nicotine catabolism. These studies establish a baseline for future analysis of e-vapor and e-vapor additives that will better inform the FDA and other governmental bodies in discussions of the risks and future regulation of these products. PMID:27041137

  17. Microcomputer interfacing and applications

    CERN Document Server

    Mustafa, M A

    1990-01-01

    This is the applications guide to interfacing microcomputers. It offers practical non-mathematical solutions to interfacing problems in many applications including data acquisition and control. Emphasis is given to the definition of the objectives of the interface, then comparing possible solutions and producing the best interface for every situation. Dr Mustafa A Mustafa is a senior designer of control equipment and has written many technical articles and papers on the subject of computers and their application to control engineering.

  18. Antimicrobial activity of murine lung cells against Staphylococcus aureus is increased in vitro and in vivo after elafin gene transfer.

    Science.gov (United States)

    McMichael, J W; Maxwell, A I; Hayashi, K; Taylor, K; Wallace, W A; Govan, J R; Dorin, J R; Sallenave, J-M

    2005-06-01

    Staphylococcus aureus is a pathogen often found in pneumonia and sepsis. In the context of the resistance of this organism to conventional antibiotics, an understanding of the regulation of natural endogenous antimicrobial molecules is of paramount importance. Previous studies have shown that both human and mouse airways express a variety of these molecules, including defensins, cathelicidins, and the four-disulfide core protein secretory leukocyte protease inhibitor. We demonstrate here by culturing mouse tracheal epithelial cells at an air-liquid interface that, despite the production of Defb1, Defb14, and Defr1 in this system, these cells are unable to clear S. aureus when exposed to this respiratory pathogen. Using an adenovirus (Ad)-mediated gene transfer strategy, we show that overexpression of elafin, an anti-elastase/antimicrobial molecule (also a member of the four-disulfide core protein family), dramatically improves the clearance of S. aureus. In addition, we also demonstrate that this overexpression is efficient in vivo and that intratracheal instillation of Ad-elafin significantly reduced the lung bacterial load and demonstrates concomitant anti-inflammatory activity by reducing neutrophil numbers and markers of lung inflammation, such as bronchoalveolar lavage levels of tumor necrosis factor and myeloperoxidase. These findings show that an increased antimicrobial activity phenotype is provided by the elafin molecule and have implications for its use in S. aureus-associated local and systemic infections. PMID:15908390

  19. Comparison of the toxicity of diesel exhaust produced by bio- and fossil diesel combustion in human lung cells in vitro

    Science.gov (United States)

    Steiner, Sandro; Czerwinski, Jan; Comte, Pierre; Popovicheva, Olga; Kireeva, Elena; Müller, Loretta; Heeb, Norbert; Mayer, Andreas; Fink, Alke; Rothen-Rutishauser, Barbara

    2013-12-01

    Alternative fuels are increasingly combusted in diesel- and gasoline engines and the contribution of such exhausts to the overall air pollution is on the rise. Recent findings on the possible adverse effects of biodiesel exhaust are contradictive, at least partly resulting from the various fuel qualities, engine types and different operation conditions that were tested. However, most of the studies are biased by undesired interactions between the exhaust samples and biological culture media. We here report how complete, freshly produced exhausts from fossil diesel (B0), from a blend of 20% rapeseed-methyl ester (RME) and 80% fossil diesel (B20) and from pure rapeseed methyl ester (B100) affect a complex 3D cellular model of the human airway epithelium in vitro by exposing the cells at the air-liquid interface. The induction of pro-apoptotic and necrotic cell death, cellular morphology, oxidative stress, and pro-inflammatory responses were assessed. Compared to B0 exhaust, B20 exhaust decreased oxidative stress and pro-inflammatory responses, whereas B100 exhaust, depending on exposure duration, decreased oxidative stress but increased pro-inflammatory responses. The effects are only very weak and given the compared to fossil diesel higher ecological sustainability of biodiesel, it appears that - at least RME - can be considered a valuable alternative to pure fossil diesel.

  20. Water at Interfaces

    DEFF Research Database (Denmark)

    Björneholm, Olle; Hansen, Martin Hangaard; Hodgson, Andrew;

    2016-01-01

    The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives...

  1. Complex Interfaces Under Change

    DEFF Research Database (Denmark)

    Rosbjerg, Dan

    mechanical processes that develop within this structure. Water-related processes at the interfaces between the compartments are complex, depending both on the interface itself, and on the characteristics of the interfaced compartments. Various aspects of global change directly or indirectly impact these...

  2. Active matter clusters at interfaces

    CERN Document Server

    Copenhagen, Katherine

    2016-01-01

    Collective and directed motility or swarming is an emergent phenomenon displayed by many self-organized assemblies of active biological matter such as clusters of embryonic cells during tissue development, cancerous cells during tumor formation and metastasis, colonies of bacteria in a biofilm, or even flocks of birds and schools of fish at the macro-scale. Such clusters typically encounter very heterogeneous environments. What happens when a cluster encounters an interface between two different environments has implications for its function and fate. Here we study this problem by using a mathematical model of a cluster that treats it as a single cohesive unit that moves in two dimensions by exerting a force/torque per unit area whose magnitude depends on the nature of the local environment. We find that low speed (overdamped) clusters encountering an interface with a moderate difference in properties can lead to refraction or even total internal reflection of the cluster. For large speeds (underdamped), wher...

  3. Water at Interfaces.

    Science.gov (United States)

    Björneholm, Olle; Hansen, Martin H; Hodgson, Andrew; Liu, Li-Min; Limmer, David T; Michaelides, Angelos; Pedevilla, Philipp; Rossmeisl, Jan; Shen, Huaze; Tocci, Gabriele; Tyrode, Eric; Walz, Marie-Madeleine; Werner, Josephina; Bluhm, Hendrik

    2016-07-13

    The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives many electrochemical reactions, and the liquid/vapor interface, which governs the uptake and release of trace gases by the oceans and cloud droplets. In this article we review some of the recent experimental and theoretical advances in our knowledge of the properties of aqueous interfaces and discuss open questions and gaps in our understanding. PMID:27232062

  4. Quantization of interface currents

    Energy Technology Data Exchange (ETDEWEB)

    Kotani, Motoko [AIMR, Tohoku University, Sendai (Japan); Schulz-Baldes, Hermann [Department Mathematik, Universität Erlangen-Nürnberg, Erlangen (Germany); Villegas-Blas, Carlos [Instituto de Matematicas, Cuernavaca, UNAM, Cuernavaca (Mexico)

    2014-12-15

    At the interface of two two-dimensional quantum systems, there may exist interface currents similar to edge currents in quantum Hall systems. It is proved that these interface currents are macroscopically quantized by an integer that is given by the difference of the Chern numbers of the two systems. It is also argued that at the interface between two time-reversal invariant systems with half-integer spin, one of which is trivial and the other non-trivial, there are dissipationless spin-polarized interface currents.

  5. Anti-inflammatory effects of antibacterials on human bronchial epithelial cells

    Directory of Open Access Journals (Sweden)

    Hatz Rudolf

    2009-09-01

    Full Text Available Abstract Background Human Bronchial epithelial cells (hu-BEC have been claimed to play a significant role in the pathogenesis of chronic inflammatory airway diseases like COPD. In this context IL-8 and GM-CSF have been shown to be key cytokines. Some antibiotics which are routinely used to treat lower respiratory tract infections have been shown to exert additional immunomodulatory or anti-inflammatory effects. We investigated whether these effects can also be detected in hu-BEC. Methods Hu-BEC obtained from patients undergoing lung resections were transferred to air-liquid-interface (ALI culture. These cultures were incubated with cefuroxime (CXM, 10-62.5 mg/l, azithromycin (AZM, 0.1-1.5 mg/l, levofloxacin (LVX, 1-8 mg/l and moxifloxacin (MXF, 1-16 mg/l. The spontaneous and TNF-α (10 ng/ml induced expression and release of IL-8 and GM-CSF were measured using PCR and ELISA in the absence or presence of these antibiotics. Results The spontaneous IL-8 and GM-CSF release was significantly reduced with MXF (8 mg/l by 37 ± 20% and 45 ± 31%, respectively (both p Conclusion Using ALI cultures of hu-BEC we observed differential effects of antibiotics on spontaneous and TNF-α induced cytokine release. Our data suggest that MXF and AZM, beyond bactericidal effects, may attenuate the inflammatory process mediated by hu-BEC.

  6. Insulin receptor substrate-1/2 mediates IL-4-induced migration of human airway epithelial cells

    Science.gov (United States)

    White, Steven R.; Martin, Linda D.; Abe, Mark K.; Marroquin, Bertha A.; Stern, Randi; Fu, Xiaoying

    2009-01-01

    Migration of airway epithelial cells (AEC) is an integral component of airway mucosal repair after injury. The inflammatory cytokine IL-4, abundant in chronic inflammatory airways diseases such as asthma, stimulates overproduction of mucins and secretion of chemokines from AEC; these actions enhance persistent airway inflammation. The effect of IL-4 on AEC migration and repair after injury, however, is not known. We examined migration in primary human AEC differentiated in air-liquid interface culture for 3 wk. Wounds were created by mechanical abrasion and followed to closure using digital microscopy. Concurrent treatment with IL-4 up to 10 ng/ml accelerated migration significantly in fully differentiated AEC. As expected, IL-4 treatment induced phosphorylation of the IL-4 receptor-associated protein STAT (signal transducer and activator of transcription)6, a transcription factor known to mediate several IL-4-induced AEC responses. Expressing a dominant negative STAT6 cDNA delivered by lentivirus infection, however, failed to block IL-4-stimulated migration. In contrast, decreasing expression of either insulin receptor substrate (IRS)-1 or IRS-2 using a silencing hairpin RNA blocked IL-4-stimulated AEC migration completely. These data demonstrate that IL-4 can accelerate migration of differentiated AEC after injury. This reparative response does not require STAT6 activation, but rather requires IRS-1 and/or IRS-2. PMID:19447894

  7. Anionic Pulmonary Surfactant Phospholipids Inhibit Inflammatory Responses from Alveolar Macrophages and U937 Cells by Binding the Lipopolysaccharide-interacting Proteins CD14 and MD-2*♦

    OpenAIRE

    Kuronuma, Koji; Mitsuzawa, Hiroaki; Takeda, Katsuyuki; Nishitani, Chiaki; Chan, Edward D.; Kuroki, Yoshio; Nakamura, Mari; Voelker, Dennis R.

    2009-01-01

    Lipopolysaccharide (LPS), derived from Gram-negative bacteria, is a major cause of acute lung injury and respiratory distress syndrome. Pulmonary surfactant is secreted as a complex mixture of lipids and proteins onto the alveolar surface of the lung. Surfactant phospholipids are essential in reducing surface tension at the air-liquid interface and preventing alveolar collapse at the end of the respiratory cycle. In the present study, we determined that palmitoyl-oleoyl-phosphatidylglycerol a...

  8. Reduction in (pro-)inflammatory responses of lung cells exposed in vitro to diesel exhaust treated with a non-catalyzed diesel particle filter

    OpenAIRE

    Steiner, Sandro; Czerwinski, Jan; Comte, Pierre; Müller, Loretta L.; Heeb, Norbert V.; Mayer, Andreas; Petri-Fink, Alke; Rothen-Rutishauser, Barbara

    2014-01-01

    Increasingly stringent regulation of particulate matter emissions from diesel vehicles has led to the widespread use of diesel particle filters (DPFs), the effect of which on exhaust toxicity is so far poorly understood. We exposed a cellular model of the human respiratory epithelium at the air-liquid interface to non-catalyzed wall-flow DPF-filtered diesel exhaust and compared the resulting biological responses to the ones observed upon exposure to unfiltered exhaust. Filtered diesel exhaust...

  9. Interface stoichiometry control to improve device voltage and modify band alignment in ZnO/Cu2O heterojunction solar cells

    OpenAIRE

    Watson, Graeme

    2014-01-01

    PUBLISHED The interface stoichiometry of cuprous oxide (Cu2O) prepared by thermal oxidation was controlled by adjusting the O2 and Zn partial pressures during ZnO sputter deposition and measured by high-resolution X-ray photoelectron spectroscopy of ultrathin (

  10. Origin of HfO2/GaAs interface states and interface passivation: A first principles study

    International Nuclear Information System (INIS)

    First principles calculations of HfO2/GaAs interfaces indicate that the interface states originate from the charge mismatch between HfO2 and GaAs surfaces. We find that a model neutral interface (HfO2 and GaAs surfaces terminated with two O and one Ga atoms per surface unit cell) removes gap states due to the balance of the interface charge. F and H can neutralize the HfO2/GaAs interface resulting in useful band offsets, thus becoming possible candidates to passivate the interface states.

  11. Proton Transfer Controlled Reactions at Liquid-Liquid Interfaces

    OpenAIRE

    Peljo, Pekka

    2013-01-01

    Electrochemistry at liquid-liquid interfaces has been a versatile area of contemporary electrochemistry for almost 40 years, with research mainly focusing on the aqueous-organic solution interface. The Galvani potential difference across such an interface, controlling the distribution of ions between the phases, can be generated either chemically or with an external voltage source. An aqueous-organic solvent interface shares similarities with the cell membrane, where several important biologi...

  12. Shape-changing interfaces:

    DEFF Research Database (Denmark)

    Rasmussen, Majken Kirkegård; Pedersen, Esben Warming; Petersen, Marianne Graves; Hornbæk, Kasper

    2015-01-01

    Shape change is increasingly used in physical user interfaces, both as input and output. Yet, the progress made and the key research questions for shape-changing interfaces are rarely analyzed systematically. We review a sample of existing work on shape-changing interfaces to address these...... shortcomings. We identify eight types of shape that are transformed in various ways to serve both functional and hedonic design purposes. Interaction with shape-changing interfaces is simple and rarely merges input and output. Three questions are discussed based on the review: (a) which design purposes may...... shape-changing interfaces be used for, (b) which parts of the design space are not well understood, and (c) why studying user experience with shape-changing interfaces is important....

  13. Universal computer interfaces

    CERN Document Server

    Dheere, RFBM

    1988-01-01

    Presents a survey of the latest developments in the field of the universal computer interface, resulting from a study of the world patent literature. Illustrating the state of the art today, the book ranges from basic interface structure, through parameters and common characteristics, to the most important industrial bus realizations. Recent technical enhancements are also included, with special emphasis devoted to the universal interface adapter circuit. Comprehensively indexed.

  14. Definition of interfaces

    OpenAIRE

    Almaghout, Hala; Bicici, Ergun; Doherty, Stephen; Gaspari, Federico; Groves, Declan; Toral, Antonio; Vangenabith, Josef; Popovic, Maja; Piperidis, Stelios

    2013-01-01

    The aim of this report is to define the interfaces for the tools used in the MT development and evaluation scenarios as included in the QTLaunchPad (QTLP) infrastructure. Specification of the interfaces is important for the interaction and interoperability of the tools in the developed QTLP infrastructure. In addressing this aim, the report provides: 1. Descriptions of the common aspects of the tools and their standardized data formats; 2. Descriptions of the interfaces for the tools f...

  15. Electromagnetic Interface Testing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Electromagnetic Interface Testing facilitysupports such testing asEmissions, Field Strength, Mode Stirring, EMP Pulser, 4 Probe Monitoring/Leveling System, and...

  16. Energetics of molecular interfaces

    Directory of Open Access Journals (Sweden)

    David Cahen

    2005-07-01

    Full Text Available Transport of charge carriers through interfaces is crucial to all electronic and optoelectronic devices, in particular devices based on organic molecular films and, especially, monomolecular layers and single molecules. The energetics of molecular interfaces are exceedingly important, therefore, and must be understood in detail so that we can model and control their behavior. This knowledge, however, is not always sufficient, as the very physics of charge carrier transport through molecular interfaces remains, at times, unclear. This article provides an overview of the main issues being researched actively in the field of interfaces involving organic molecules, and points out areas where progress has been made and where basic questions remain unanswered.

  17. Active liquid/liquid interfaces: contributions of non linear optics and tensiometry

    International Nuclear Information System (INIS)

    Liquid-liquid extraction processes are widely used in the industrial fields of selective separation. Despite its numerous applications, the microscopic mechanisms which occur during a liquid-liquid extraction processes are really unknown specially at the liquid/liquid interface. Thus, this work deals on the understanding of the phenomena which drive the mass transfer across a liquid/liquid interface. Two experimental techniques were used in this work: dynamic interfacial tension measurement and non-linear optical experiments. Along with the use of this experimental approach, a numerical model describing the mass transfer dynamic has been developed. This model works under the assumption that both diffusion and a chemical step describing adsorption and desorption processes contribute to the global transfer kinetics. Model systems of surfactant molecules, chromophore molecules and complexing molecule were investigated at liquid/liquid and air/liquid interface. Interfacial phenomena like adsorption, surface aggregation and ion complexing were studied. Finally, the methodology developed in this work was applied to studied an extractant molecule with potential industrial application. (author)

  18. Interface identification in magnetic fluid dynamics

    Directory of Open Access Journals (Sweden)

    Brauer Hartmut

    2003-01-01

    Full Text Available In magnetic fluid dynamics appears the problem of reconstruction of free boundary between conducting fluids, e.g. in aluminum electrolysis cells. We have investigated how the interface between two fluids of different conductivity of a highly simplified model of an aluminum electrolysis cell could be reconstructed by means of external magnetic field measurements using simple genetic algorithm.

  19. Soft matter at aqueous interfaces

    CERN Document Server

    Liu, Yi

    2016-01-01

    This book covers the science of interfaces between an aqueous phase and a solid, another liquid or a gaseous phase, starting from the basic physical chemistry all the way to state-of-the-art research developments. Both experimental and theoretical methods are treated thanks to the contributions of a distinguished list of authors who are all active researchers in their respective fields. The properties of these interfaces are crucial for a wide variety of processes, products and biological systems and functions, such as the formulation of personal care and food products, paints and coatings, microfluidic and lab-on-a-chip applications, cell membranes, and lung surfactants. Accordingly, research and expertise on the subject are spread over a broad range of academic disciplines and industrial laboratories. This book brings together knowledge from these different places with the aim of fostering education, collaborations and research progress.

  20. Modeling and simulation of the motion of deformable interfaces in a confined geometry : application to the study of the flow of red blood cells in microcirculation

    OpenAIRE

    Aouane, Othmane

    2015-01-01

    Vesicles are extensively used as a model for understanding dynamics and deformation of red blood cells at the individual level but also regarding collective phenomena and rheology. Vesicles’ membranes withstand to bending but do not have a shear resistance, unlike red blood cells, but they still share several dynamical properties with red blood cells, like tank-treading and tumbling under linear shear flow, or parachute and slipper shapes under Poiseuille flow. The red blood cells are known t...

  1. Functional effects of TGF-β1 on mesenchymal stem cell mobilization in cockroach allergen-induced asthma.

    Science.gov (United States)

    Gao, Peisong; Zhou, Yufeng; Xian, Lingling; Li, Changjun; Xu, Ting; Plunkett, Beverly; Huang, Shau-Ku; Wan, Mei; Cao, Xu

    2014-05-15

    Mesenchymal stem cells (MSCs) have been suggested to participate in immune regulation and airway repair/remodeling. TGF-β1 is critical in the recruitment of stem/progenitor cells for tissue repair, remodeling, and cell differentiation. In this study, we sought to investigate the role of TGF-β1 in MSC migration in allergic asthma. We examined nestin expression (a marker for MSCs) and TGF-β1 signaling activation in airways in cockroach allergen extract (CRE)-induced mouse models. Compared with control mice, there were increased nestin(+) cells in airways and higher levels of active TGF-β1 in serum and p-Smad2/3 expression in lungs of CRE-treated mice. Increased activation of TGF-β1 signaling was also found in CRE-treated MSCs. We then assessed MSC migration induced by conditioned medium from CRE-challenged human epithelium in air/liquid interface culture in Transwell assays. MSC migration was stimulated by epithelial-conditioned medium, but was significantly inhibited by either TGF-β1-neutralizing Ab or TβR1 inhibitor. Intriguingly, increased migration of MSCs from blood and bone marrow to the airway was also observed after systemic injection of GFP(+) MSCs and from bone marrow of Nes-GFP mice following CRE challenge. Furthermore, TGF-β1-neutralizing Ab inhibited the CRE-induced MSC recruitment, but promoted airway inflammation. Finally, we investigated the role of MSCs in modulating CRE-induced T cell response and found that MSCs significantly inhibited CRE-induced inflammatory cytokine secretion (IL-4, IL-13, IL-17, and IFN-γ) by CD4(+) T cells. These results suggest that TGF-β1 may be a key promigratory factor in recruiting MSCs to the airways in mouse models of asthma. PMID:24711618

  2. Interface or Interlace?

    DEFF Research Database (Denmark)

    Hansen, Lone Koefoed; Wamberg, Jacob

    2005-01-01

    Departing from an analysis of the computer's indeterminate location between medium and machine, this paper problematises the idea of a clear-cut interface in complex computing, especially Augmented Reality. The idea and pratice of the interface is derived from the medium as a representational...... art works, especially Phunsombatlert's Path of Illusion, Dobson's Blendie, the Canadian collective Whisper and Rinaldo's Augmented Fish Reality....

  3. Icinga Monitoring System Interface

    CERN Document Server

    Neculae, Alina Georgiana

    2014-01-01

    The aim of this project is to develop a web interface that would be used by the Icinga monitoring system to manage the CMS online cluster, in the experimental site. The interface would allow users to visualize the information in a compressed and intuitive way, as well as modify the information of each individual object and edit the relationships between classes.

  4. Interface colloidal robotic manipulator

    Energy Technology Data Exchange (ETDEWEB)

    Aronson, Igor; Snezhko, Oleksiy

    2015-08-04

    A magnetic colloidal system confined at the interface between two immiscible liquids and energized by an alternating magnetic field dynamically self-assembles into localized asters and arrays of asters. The colloidal system exhibits locomotion and shape change. By controlling a small external magnetic field applied parallel to the interface, structures can capture, transport, and position target particles.

  5. User Interface History

    DEFF Research Database (Denmark)

    Jørgensen, Anker Helms; Myers, Brad A

    2008-01-01

    User Interfaces have been around as long as computers have existed, even well before the field of Human-Computer Interaction was established. Over the years, some papers on the history of Human-Computer Interaction and User Interfaces have appeared, primarily focusing on the graphical interface era...... and early visionaries such as Bush, Engelbart and Kay. With the User Interface being a decisive factor in the proliferation of computers in society and since it has become a cultural phenomenon, it is time to paint a more comprehensive picture of its history. This SIG will investigate the possibilities...... of  launching a concerted effort towards creating a History of User Interfaces. ...

  6. Improvement of In{sub 2}S{sub 3}/ZnCuInS{sub 2} interfaces for wide-gap solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Teruaki; Negami, Takayuki [Panasonic Corporation, 1006 Kadoma, Kadoma City, Osaka 571-8501 (Japan); Matsubara, Koji; Niki, Shigeru [AIST, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8561 (Japan)

    2015-06-15

    We have fabricated superstrate In{sub 2}S{sub 3}/ZnCuInS{sub 2} (Zn{sub 2x}Cu{sub 1-x}In{sub 1-x}S{sub 2}, ZCIS) solar cells as the top cell of multi-junction solar cells. The ZCIS and In{sub 2}S{sub 3} thin films were deposited by spray pyrolysis deposition (SPD) and an efficiency of 4.4% was achieved with bandgap of 1.8 eV. However, in the structure of superstrate type solar cells, interdiffusion have been caused between the buffer layer and the ZCIS layer. In order to suppress the interdiffusion, we have fabricated In{sub 2}S{sub 3}/ZCIS substrate type solar cells. The thickness of the interdiffusion region decreased from 70 nm of the superstrate cell to 15 nm of the substrate cell. As a result, the substrate cell with bandgap of 1.8 eV showed V{sub OC} of 0.71 V and FF of 0.55 higher than those of the superstrate cells. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. The Java Legacy Interface

    DEFF Research Database (Denmark)

    Korsholm, Stephan

    2007-01-01

    The Java Legacy Interface is designed to use Java for encapsulating native legacy code on small embedded platforms. We discuss why existing technologies for encapsulating legacy code (JNI) is not sufficient for an important range of small embedded platforms, and we show how the Java Legacy...... Interface offers this previously missing functionality. We describe an implementation of the Java Legacy Interface for a particular virtual machine, and how we have used this virtual machine to integrate Java with an existing, commercial, soft real-time, C/C++ legacy platform....

  8. The computer graphics interface

    CERN Document Server

    Steinbrugge Chauveau, Karla; Niles Reed, Theodore; Shepherd, B

    2014-01-01

    The Computer Graphics Interface provides a concise discussion of computer graphics interface (CGI) standards. The title is comprised of seven chapters that cover the concepts of the CGI standard. Figures and examples are also included. The first chapter provides a general overview of CGI; this chapter covers graphics standards, functional specifications, and syntactic interfaces. Next, the book discusses the basic concepts of CGI, such as inquiry, profiles, and registration. The third chapter covers the CGI concepts and functions, while the fourth chapter deals with the concept of graphic obje

  9. The Java Legacy Interface

    DEFF Research Database (Denmark)

    Korsholm, Stephan

    The Java Legacy Interface is designed to use Java for encapsulating native legacy code on small embedded platforms. We discuss why existing technologies for encapsulating legacy code (JNI) is not sufficient for an important range of small embedded platforms, and we show how the Java Legacy...... Interface offers this previously missing functionality. We describe an implementation of the Java Legacy Interface for a particular virtual machine, and how we have used this virtual machine to integrate Java with an existing, commercial, soft real-time, C/C++ legacy platform....

  10. The interface effect

    CERN Document Server

    Galloway, Alexander R

    2013-01-01

    Interfaces are back, or perhaps they never left. The familiar Socratic conceit from the Phaedrus, of communication as the process of writing directly on the soul of the other, has returned to center stage in today's discussions of culture and media. Indeed Western thought has long construed media as a grand choice between two kinds of interfaces. Following the optimistic path, media seamlessly interface self and other in a transparent and immediate connection. But, following the pessimistic path, media are the obstacles to direct communion, disintegrating self and other into misunderstanding

  11. Satellite formation during bubble transition through an interface between immiscible liquids

    KAUST Repository

    Li, Erqiang

    2014-03-12

    When a bubble rises to an interface between two immiscible liquids, it can pass through the interface, if this is energetically favourable, i.e. The bubble preferring the side of the interface with the lower air-liquid surface tension. Once the intermediate film between the bubble and the interface has drained sufficiently, the bubble makes contact with the interface, forming a triple-line and producing strong capillary waves which travel around the bubble and can pinch off a satellite on the opposite side, akin to the dynamics in the coalescence cascade. We identify the critical Ohnesorge numbers where such satellites are produced and characterize their sizes. The total transition time scales with the bubble size and differential surface tension, while the satellite pinch-off time scales with the capillary-inertial time of the pool liquid, which originally surrounds the bubble. We also use high-speed video imaging to study the motion of the neck of the contact. For low viscosity we show that it grows in time with a power-law exponent between 0.44 and 0.50, with a prefactor modified by the net sum of the three interfacial tensions. Increasing the viscosity of the receiving liquid drop drastically slows down the motion of the triple-line, when the Ohnesorge number exceeds ${\\\\sim }$0.08. This differs qualitatively from the coalescence of two miscible drops of different viscosities, where the lower viscosity sets the coalescence speed. We thereby propose a strong resistance from the triple-line. © 2014 Cambridge University Press.

  12. Nanoscale interface for organic electronics

    CERN Document Server

    Iwamoto, Mitsumasa; Lee, Takhee

    2010-01-01

    The scope of this book will be focused on the interface issues and problems in organic materials as electronic device applications. The organic material electronics is a rapidly progressing field for potential applications in flexible field effect transistors, plastic solar cells, organic luminescent devices, etc. However, the performance of these organic devices is still not sufficient. To enhance the understanding and practical applications of organic devices, we need to understand the fundamental organic device physics which is somewhat different from the conventional inorganic device physi

  13. Isolation and characterization of alveolar epithelial type II cells derived from mouse embryonic stem cells.

    Science.gov (United States)

    Sun, Huanhuan; Quan, Yuan; Yan, Qing; Peng, Xinmiao; Mao, Zhengmei; Wetsel, Rick A; Wang, Dachun

    2014-06-01

    The use of embryonic stem cells (ESCs) to regenerate distal lung epithelia damaged by injuries or diseases requires development of safe and efficient methodologies that direct ESC differentiation into transplantable distal lung epithelial progenitors. Time-consuming culture procedure and low differentiation efficiency are major problems that are associated with conventional differentiation approaches via embryoid body formation. The use of a growth factor cocktail or a lung-specific cell-conditioned medium to enrich definitive endoderm for efficient differentiation of mouse ESCs (mESC) into alveolar epithelial progenitor type II cells (ATIICs) has been reported, but not yet successful for generating a homogenous population of ATIICs for tissue regeneration purpose, and it remains unclear whether or not those mESC-derived ATIICs possess normal biological functions. Here, we report a novel method using a genetically modified mESC line harboring an ATIIC-specific neomycin(R) transgene in Rosa 26 locus. We showed that ATIICs can be efficiently differentiated from mESCs as early as day 7 by culturing them directly on Matrigel-coated plates in DMEM containing 15% knockout serum replacement. With this culture condition, the genetically modified mESCs can be selectively differentiated into a homogenous population (>99%) of ATIICs. Importantly, the mESC-derived ATIICs (mESC-ATIICs) exhibited typical lamellar bodies and expressed surfactant protein A, B, and C as normal control ATIICs. When cultured with an air-liquid-interface culture system in Small Airway Epithelial Cell Growth Medium, the mESC-ATIICs can be induced to secrete surfactant proteins after being treated with dibutyryl cAMP+dexamethasone. These mESC-ATIICs can synthesize and secrete surfactant lipid in response to secretagogue, demonstrating active surfactant metabolism in mESC-ATIICs as that seen in normal control ATIICs. In addition, we demonstrated that the selected mESC-ATIICs can be maintained on Matrigel

  14. The ATLAS metadata interface

    International Nuclear Information System (INIS)

    AMI was chosen as the ATLAS dataset selection interface in July 2006. It is the main interface for searching for ATLAS data using physics metadata criteria. AMI has been implemented as a generic database management framework which allows parallel searching over many catalogues, which may have differing schema. The main features of the web interface will be described; in particular the powerful graphic query builder. The use of XML/XLST technology ensures that all commands can be used either on the web or from a command line interface via a web service. We also describe the overall architecture of ATLAS metadata and the different actors and granularity involved, and the place of AMI within this architecture. We discuss the problems involved in the correlation of metadata of differing granularity, and propose a solution for information mediation

  15. Interface Anywhere Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To illustrate the viability of this technology, a prototype Natural User Interface (NUI) was developed as a proof-of-concept for system control.  Gesture and...

  16. Electrons at helium interfaces

    OpenAIRE

    Leiderer, Paul

    1984-01-01

    Two-dimensional layers of charges trapped at the boundaries between the various helium phases strongly interact with these interfaces at high electric fields. The coupling, which leads to an electrohydrodynamic instability, provides new methods for studying helium properties.

  17. Scalable coherent interface

    International Nuclear Information System (INIS)

    The Scalable Coherent Interface (IEEE P1596) is establishing an interface standard for very high performance multiprocessors, supporting a cache-coherent-memory model scalable to systems with up to 64K nodes. This Scalable Coherent Interface (SCI) will supply a peak bandwidth per node of 1 GigaByte/second. The SCI standard should facilitate assembly of processor, memory, I/O and bus bridge cards from multiple vendors into massively parallel systems with throughput far above what is possible today. The SCI standard encompasses two levels of interface, a physical level and a logical level. The physical level specifies electrical, mechanical and thermal characteristics of connectors and cards that meet the standard. The logical level describes the address space, data transfer protocols, cache coherence mechanisms, synchronization primitives and error recovery. In this paper we address logical level issues such as packet formats, packet transmission, transaction handshake, flow control, and cache coherence. 11 refs., 10 figs

  18. Effect of co-adsorption dye on the electrode interface (Ru complex/TiO2 of dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    M. Honda

    2013-07-01

    Full Text Available The co-adsorption interface structure of isothiocyanate (R-N=C=S in N719 dye was investigated using a system of N719 alone and an N719 + D131 co-adsorption system. The sulfur core level (S 1s and sulfur K absorption edge (S K-edge were examined in detail using X-ray photoelectron spectroscopy (XPS and near-edge X-ray absorption fine structure (NEXAFS, respectively. The S 1s XPS spectra revealed that the binding energies were shifted approximately 9 eV higher in N719 alone because of interactions between the R-N=C=S of N719 and nanocrystalline TiO2. However, this strong interaction disappeared in the N719 + D131 co-adsorption system. Comparing the S K-edge NEXAFS spectra against the case of N719 alone revealed that the resonance adsorption peak at 2483 eV, which was attributed to an interaction between sulfur and the substrate, did not appear in the N719 + D131 co-adsorption system. This peak was observed under oblique incidence, but was almost indiscernible under normal incidence. These results indicate that the interface structure of sulfur atoms that strongly interacts with nanocrystalline TiO2 substrate changes to become non-interacting in the N719 + D131 co-adsorption system. We conclude that the co-adsorption dye has the unique property of inhibiting strong interactions between the S atom in the R-N=C=S group of the N719 dye and the nanocrystalline TiO2 surface.

  19. Silent Speech Interfaces

    OpenAIRE

    Denby, B; Schultz, T.; Honda, K.; Hueber, T.; Gilbert, J.M.; Brumberg, J.S.

    2010-01-01

    Abstract The possibility of speech processing in the absence of an intelligible acoustic signal has given rise to the idea of a `silent speech? interface, to be used as an aid for the speech handicapped, or as part of a communications system operating in silence-required or high-background-noise environments. The article first outlines the emergence of the silent speech interface from the fields of speech production, automatic speech processing, speech pathology research, and telec...

  20. Intelligent Multimedia Interfaces

    OpenAIRE

    Maybury, Mark T.

    1992-01-01

    On Monday, 15 July 1991, prior to the Ninth National Conference on Artificial Intelligence (AAAI-91) in Anaheim, California, over 50 scientists and engineers attended the AAAI-91 Workshop on Intelligent Multimedia Interfaces. The purpose of the workshop was threefold: (1) bring together researchers and practitioners to report on current advances in intelligent multimedia interface systems and their underlying theories, (2) foster scientific interchange among these individuals, and (3) evaluat...

  1. Serial interface controller

    Energy Technology Data Exchange (ETDEWEB)

    Kandasamy, A.

    1995-04-14

    The idea of building a Serial Interface Controller (SIC) proposed by Paul O`Connor, Instrumentation Division, BNL is to determine the feasibility of incorporating a Serial Interface Controlled CMOS IC`s for charge amplification, shaping, analog storage and multiplexing used in particle detectors for high energy physics experiments. The serial data pumped into the CMOS ICs will be used to control many circuit parameters like digitally controlled gain, shaping time, precision preamplifier calibration circuits and many other parameters like timing discriminators mode of operation. The SIC board built will be tested on a Serial Interface Controlled Digital - to - Analog Convertor, which follows either Motorola`s SPI/QSPI or National Semiconductors Microwire interface technique. The DAC chosen for this was MAXIM`s MAX537, a Quad, 12-bit DAC. The function of this controller can be achieved by using some on-shelf micro-controllers like the Motorola`s MC68HC11, which offers dedicated SPI ports. The drawback encountered in using this controller is the overhead involved in putting together an user interface where the user can dynamically change its settings and load the SIC device. This is very critical in testing fewer number of CMOS IC`s having SIC. The SIC board described here takes care of this dynamic user interface issue.

  2. CdSe magic-sized quantum dots incorporated in biomembrane models at the air-water interface composed of components of tumorigenic and non-tumorigenic cells.

    Science.gov (United States)

    Goto, Thiago E; Lopes, Carla C; Nader, Helena B; Silva, Anielle C A; Dantas, Noelio O; Siqueira, José R; Caseli, Luciano

    2016-07-01

    Cadmium selenide (CdSe) magic-sized quantum dots (MSQDs) are semiconductor nanocrystals with stable luminescence that are feasible for biomedical applications, especially for in vivo and in vitro imaging of tumor cells. In this work, we investigated the specific interaction of CdSe MSQDs with tumorigenic and non-tumorigenic cells using Langmuir monolayers and Langmuir-Blodgett (LB) films of lipids as membrane models for diagnosis of cancerous cells. Surface pressure-area isotherms and polarization modulation reflection-absorption spectroscopy (PM-IRRAS) showed an intrinsic interaction between the quantum dots, inserted in the aqueous subphase, and Langmuir monolayers constituted either of selected lipids or of tumorigenic and non-tumorigenic cell extracts. The films were transferred to solid supports to obtain microscopic images, providing information on their morphology. Similarity between films with different compositions representing cell membranes, with or without the quantum dots, was evaluated by atomic force microscopy (AFM) and confocal microscopy. This study demonstrates that the affinity of quantum dots for models representing cancer cells permits the use of these systems as devices for cancer diagnosis. PMID:27107554

  3. The Fetal Allograft Revisited: Does the Study of an Ancient Invertebrate Species Shed Light on the Role of Natural Killer Cells at the Maternal-Fetal Interface?

    Directory of Open Access Journals (Sweden)

    Breton F. Barrier

    2008-07-01

    Full Text Available Human pregnancy poses a fundamental immunological problem because the placenta and fetus are genetically different from the host mother. Classical transplantation theory has not provided a plausible solution to this problem. Study of naturally occurring allogeneic chimeras in the colonial marine invertebrate, Botryllus schlosseri, has yielded fresh insight into the primitive development of allorecognition, especially regarding the role of natural killer (NK cells. Uterine NK cells have a unique phenotype that appears to parallel aspects of the NK-like cells in the allorecognition system of B. schlosseri. Most notably, both cell types recognize and reject “missing self” and both are involved in the generation of a common vascular system between two individuals. Chimeric combination in B. schlosseri results in vascular fusion between two individual colonies; uterine NK cells appear essential to the establishment of adequate maternal-fetal circulation. Since human uterine NK cells appear to de-emphasize primary immunological function, it is proposed that they may share the same evolutionary roots as the B. schlosseri allorecognition system rather than a primary origin in immunity.

  4. E-Cigarette Affects the Metabolome of Primary Normal Human Bronchial Epithelial Cells.

    Directory of Open Access Journals (Sweden)

    Argo Aug

    Full Text Available E-cigarettes are widely believed to be safer than conventional cigarettes and have been even suggested as aids for smoking cessation. However, while reasonable with some regards, this judgment is not yet supported by adequate biomedical research data. Since bronchial epithelial cells are the immediate target of inhaled toxicants, we hypothesized that exposure to e-cigarettes may affect the metabolome of human bronchial epithelial cells (HBEC and that the changes are, at least in part, induced by oxidant-driven mechanisms. Therefore, we evaluated the effect of e-cigarette liquid (ECL on the metabolome of HBEC and examined the potency of antioxidants to protect the cells. We assessed the changes of the intracellular metabolome upon treatment with ECL in comparison of the effect of cigarette smoke condensate (CSC with mass spectrometry and principal component analysis on air-liquid interface model of normal HBEC. Thereafter, we evaluated the capability of the novel antioxidant tetrapeptide O-methyl-l-tyrosinyl-γ-l-glutamyl-l-cysteinylglycine (UPF1 to attenuate the effect of ECL. ECL caused a significant shift in the metabolome that gradually gained its maximum by the 5th hour and receded by the 7th hour. A second alteration followed at the 13th hour. Treatment with CSC caused a significant initial shift already by the 1st hour. ECL, but not CSC, significantly increased the concentrations of arginine, histidine, and xanthine. ECL, in parallel with CSC, increased the content of adenosine diphosphate and decreased that of three lipid species from the phosphatidylcholine family. UPF1 partially counteracted the ECL-induced deviations, UPF1's maximum effect occurred at the 5th hour. The data support our hypothesis that ECL profoundly alters the metabolome of HBEC in a manner, which is comparable and partially overlapping with the effect of CSC. Hence, our results do not support the concept of harmlessness of e-cigarettes.

  5. Differentiation of human bronchial epithelial cells: role of hydrocortisone in development of ion transport pathways involved in mucociliary clearance.

    Science.gov (United States)

    Zaidman, Nathan A; Panoskaltsis-Mortari, Angela; O'Grady, Scott M

    2016-08-01

    Glucocorticoids strongly influence the mucosal-defense functions performed by the bronchial epithelium, and inhaled corticosteroids are critical in the treatment of patients with inflammatory airway diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. A common pathology associated with these diseases is reduced mucociliary clearance, a defense mechanism involving the coordinated transport of salt, water, and mucus by the bronchial epithelium, ultimately leading to retention of pathogens and particles in the airways and to further disease progression. In the present study we investigated the role of hydrocortisone (HC) in differentiation and development of the ion transport phenotype of normal human bronchial epithelial cells under air-liquid interface conditions. Normal human bronchial epithelial cells differentiated in the absence of HC (HC0) showed significantly less benzamil-sensitive short-circuit current than controls, as well as a reduced response after stimulation with the selective β2-adrenergic receptor agonist salbutamol. Apical membrane localization of epithelial Na(+) channel α-subunits was similarly reduced in HC0 cells compared with controls, supporting a role of HC in the trafficking and density of Na(+) channels in the plasma membrane. Additionally, glucocorticoid exposure during differentiation regulated the transcription of cystic fibrosis transmembrane conductance regulator and β2-adrenergic receptor mRNAs and appeared to be necessary for the expression of cystic fibrosis transmembrane conductance regulator-dependent anion secretion in response to β2-agonists. HC had no significant effect on surface cell differentiation but did modulate the expression of mucin mRNAs. These findings indicate that glucocorticoids support mucosal defense by regulating critical transport pathways essential for effective mucociliary clearance. PMID:27306366

  6. Effects of interface modification with self-assembled monolayers on the photovoltaic performance of CdS quantum dots sensitized solar cells

    International Nuclear Information System (INIS)

    We employ 3-PPA, BPA and APPA as self-assembled monolayers (SAMs), who owns the same phosphonic acid headgroup but different tail group, to modify the surface of ZnO nanorods. Their effects on the photovoltaic performance of quantum dots sensitized soar cells are systematically investigated. The results indicate that the deposition of SAMs not only passivates the surface defects of ZnO nanorods, but also tunes their surface work function to adjust the band alignment of solar cells. In particular, the 3-PPA modification exhibits the best passivation effect and makes the surface work function of ZnO decreases by 1.04 eV to realize a better band alignment due to its electron-withdrawing tailgroup, which results in an enhancement in photovoltaic conversion efficiency of solar cells

  7. β-Phase poly(vinylidene fluoride) films encouraged more homogeneous cell distribution and more significant deposition of fibronectin towards the cell–material interface compared to α-phase poly(vinylidene fluoride) films

    Energy Technology Data Exchange (ETDEWEB)

    Low, Y.K.A.; Zou, X. [School of Materials Science and Engineering, Nanyang Technological University, N4.1 50 Nanyang Avenue, Singapore 639798 (Singapore); Fang, Y.M. [School of Computer Engineering, Nanyang Technological University, N4 50 Nanyang Avenue, Singapore 639798 (Singapore); Wang, J.L. [School of Materials Science and Engineering, Nanyang Technological University, N4.1 50 Nanyang Avenue, Singapore 639798 (Singapore); Lin, W.S. [School of Computer Engineering, Nanyang Technological University, N4 50 Nanyang Avenue, Singapore 639798 (Singapore); Boey, F.Y.C. [School of Materials Science and Engineering, Nanyang Technological University, N4.1 50 Nanyang Avenue, Singapore 639798 (Singapore); Ng, K.W., E-mail: kwng@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, N4.1 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2014-01-01

    The piezoelectric response from β-phase poly(vinylidene fluoride) (PVDF) can potentially be exploited for biomedical application. We hypothesized that α and β-phase PVDF exert direct but different influence on cellular behavior. α- and β-phase PVDF films were synthesized through solution casting and characterized with FT-IR, XRD, AFM and PFM to ensure successful fabrication of α and β-phase PVDF films. Cellular evaluation with L929 mouse fibroblasts over one-week was conducted with AlamarBlue® metabolic assay and PicoGreen® proliferation assay. Immunostaining of fibronectin investigated the extent and distribution of extracellular matrix deposition. Image saliency analysis quantified differences in cellular distribution on the PVDF films. Our results showed that β-phase PVDF films with the largest area expressing piezoelectric effect elicited highest cell metabolic activity at day 3 of culture. Increased fibronectin adsorption towards the cell–material interface was shown on β-phase PVDF films. Image saliency analysis showed that fibroblasts on β-phase PVDF films were more homogeneously distributed than on α-phase PVDF films. Taken collectively, the different molecular packing of α and β-phase PVDF resulted in differing physical properties of films, which in turn induced differences in cellular behaviors. Further analysis of how α and β-phase PVDF may evoke specific cellular behavior to suit particular application will be intriguing. - Highlights: • β-Phase PVDF exhibited strongest piezoelectric effects compared to α-phase PVDF. • β-Phase PVDF induced more homogeneous cell distribution than α-phase PVDF. • β-Phase PVDF encouraged more fibronectin deposition at the cell–material interface.

  8. β-Phase poly(vinylidene fluoride) films encouraged more homogeneous cell distribution and more significant deposition of fibronectin towards the cell–material interface compared to α-phase poly(vinylidene fluoride) films

    International Nuclear Information System (INIS)

    The piezoelectric response from β-phase poly(vinylidene fluoride) (PVDF) can potentially be exploited for biomedical application. We hypothesized that α and β-phase PVDF exert direct but different influence on cellular behavior. α- and β-phase PVDF films were synthesized through solution casting and characterized with FT-IR, XRD, AFM and PFM to ensure successful fabrication of α and β-phase PVDF films. Cellular evaluation with L929 mouse fibroblasts over one-week was conducted with AlamarBlue® metabolic assay and PicoGreen® proliferation assay. Immunostaining of fibronectin investigated the extent and distribution of extracellular matrix deposition. Image saliency analysis quantified differences in cellular distribution on the PVDF films. Our results showed that β-phase PVDF films with the largest area expressing piezoelectric effect elicited highest cell metabolic activity at day 3 of culture. Increased fibronectin adsorption towards the cell–material interface was shown on β-phase PVDF films. Image saliency analysis showed that fibroblasts on β-phase PVDF films were more homogeneously distributed than on α-phase PVDF films. Taken collectively, the different molecular packing of α and β-phase PVDF resulted in differing physical properties of films, which in turn induced differences in cellular behaviors. Further analysis of how α and β-phase PVDF may evoke specific cellular behavior to suit particular application will be intriguing. - Highlights: • β-Phase PVDF exhibited strongest piezoelectric effects compared to α-phase PVDF. • β-Phase PVDF induced more homogeneous cell distribution than α-phase PVDF. • β-Phase PVDF encouraged more fibronectin deposition at the cell–material interface

  9. Environmental materials and interfaces

    International Nuclear Information System (INIS)

    A workshop that explored materials and interfaces research needs relevant to national environmental concerns was conducted at Pacific Northwest Laboratory. The purposes of the workshop were to refine the scientific research directions being planned for the Materials and Interface Program in the Molecular Science Research Center (MSRC) and further define the research and user equipment to the included as part of the proposed Environmental and Molecular Science Laboratory (EMSL). Three plenary information sessions served to outline the background, objectives, and status of the MSRC and EMSL initiatives; selected specific areas with environmentally related materials; and the status of capabilities and facilities planned for the EMSL. Attention was directed to four areas where materials and interface science can have a significant impact on prevention and remediation of environmental problems: in situ detection and characterization of hazardous wastes (sensors), minimization of hazardous waste (separation membranes, ion exchange materials, catalysts), waste containment (encapsulation and barrier materials), and fundamental understanding of contaminant transport mechanisms. During all other sessions, the participants were divided into three working groups for detailed discussion and the preparation of a written report. The working groups focused on the areas of interface structure and chemistry, materials and interface stability, and materials synthesis. These recommendations and suggestions for needed research will be useful for other researchers in proposing projects and for suggesting collaborative work with MSRC researchers. 1 fig

  10. Refraction of $e^-$ beams due to plasma lensing at a plasma-vacuum interface -- applied to beam deflection in a Copper cell with electrical RF-breakdown plasma

    CERN Document Server

    Sahai, Aakash A

    2014-01-01

    We formulate a possible description of the deflection of a relativistic $e^-$ beam in an inhomogeneous copper plasma, encountered by the beam when propagating through a accelerating cell that has undergone a high electric-field RF-breakdown. It is well known that an inhomogeneous plasma forms and may last for up to a few micro-seconds, until recombination in an accelerating structure where a field-emission triggers melting and ionization of RF-cell wall deformity. We present a preliminary model for the beam deflection due to collective plasma response based upon the beam density, plasma density and interaction length.

  11. User interface description languages for next generation user interfaces

    OpenAIRE

    Shaer, Orit; Jacob, Robert; Green, Mark; LUYTEN, Kris

    2008-01-01

    In recent years HCI researchers have developed a broad range of new interfaces that diverge from the "window, icon, menu, pointing device" (WIMP) paradigm, employing a variety of novel interaction techniques and devices. Developers of these next generation user interfaces face challenges that are currently not addressed by state of the art user interface software tools. As part of the user interface software community’s effort to address these challenges, the concept of a User Interface Descr...

  12. Fluidic Dielectrophoresis of Aqueous Electrical Interfaces

    Science.gov (United States)

    Gagnon, Zachary

    2014-11-01

    To date, alternating current (AC) electric fields have been exploited to dielectrophoretically manipulate bubbles, liquid drops, particles, biomolecules and cells. Research and applications in this area, however, has been primarily limited to the interfaces formed between two immiscible metal-liquid, particle-liquid, or gas-liquid surfaces on particles. The influence of AC electric fields across aqueous liquid-liquid interfaces remains relatively unexplored. Fundamentally, many electrokinetic phenomena arise from discontinuities in ionic flux and charge accumulation at electrical interfaces, and here I explore the influence of AC electric fields on the electrical interface created between two aqueous liquids with disparaging electrical properties Using a microfluidic channel with embedded electrodes, two fluid streams - one with a greater electrical conductivity, the other a greater dielectric constant - were made to flow side-by-side. An AC electric field was applied across the flow channel and fluid was observed to displace across the phase interface. The displacement direction is AC frequency dependent, and is attributed to the Maxwell-Wagner interfacial polarization at the liquid-liquid electrical interface. At low AC frequency, below the interfacial charge relaxation time, the high conductive stream is observed to displace into the high dielectric stream. Above this frequency, the direction of liquid injection reverses, and the high dielectric stream injects into the high conductivity stream. An analytical model is presented for this liquid crossover frequency, and applied towards biosensing applications.

  13. Wettability alteration by novel betaines at polymer-aqueous solution interfaces

    Science.gov (United States)

    Hu, Song-Shuang; Zhang, Lei; Xu, Zhi-Cheng; Gong, Qing-Tao; Jin, Zhi-Qiang; Luo, Lan; Zhang, Lu; Zhao, Sui

    2015-11-01

    The wettability of alkyl carboxylbetaine (18C) and alkyl sulfobetaine (18S) at polytetrafluoroethylene (PTFE) and polymethylmethacrylate (PMMA) surfaces have been investigated and the different physicochemical parameters such as critical micelle concentration (CMC), surface tension, contact angle, surface excess, adhesional tension and work of adhesion have been estimated. The results show that the contact angle of 18C and 18S for both solids keep almost a constant value in a wide range of surfactant concentration, but the sharp decrease of contact angle appears after CMC of individual surfactant solution because of the continued increase in surfactant molecules adsorption at solid-liquid interface above CMC, which is quite different from traditional surfactants reported in the literature. In addition, 18C has significantly lower contact angle values on PTFE at high concentrations. For PTFE and PMMA there is a linear relationship existing between the adhesional and surface tension in a range of certain concentrations for all investigated surfactants. The values of slope suggest that adsorption of 18C and 18S at PTFE/PMMA-liquid interfaces are less than that at air-liquid, and the orientation of the surfactant molecules at PTFE-liquid and PMMA-liquid interfaces should not be the same. Moreover, the decrease of PTFE-liquid interfacial tension has been observed while the PMMA-liquid interfacial tension increases at first and decreases afterwards for 18C and 18S. Especially for PTFE, the decrease of γSL for 18C is larger than that for 18S, which indicates that 18S molecules may be vertical orientation due to steric effect while the hemimicelle has been formed for 18C at the PTFE interface. On the other hand, the addition of surfactant molecules will adsorb onto monolayer at PMMA surface again through hydrophobic interaction with hydrophilic group toward the bulk phase of solution above CMC.

  14. The song of lipids and proteins: dynamic lipid-protein interfaces in the regulation of plant cell polarity at different scales

    Czech Academy of Sciences Publication Activity Database

    Sekereš, Juraj; Pleskot, Roman; Pejchar, Přemysl; Žárský, Viktor; Potocký, Martin

    2015-01-01

    Roč. 66, č. 6 (2015), s. 1587-1598. ISSN 0022-0957 R&D Projects: GA ČR GA13-19073S Grant ostatní: GA MŠk(CZ) LO1417 Institutional support: RVO:61389030 Keywords : Cell polarity * endocytosis * exocytosis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.526, year: 2014

  15. High temperature interface superconductivity

    Science.gov (United States)

    Gozar, A.; Bozovic, I.

    2016-02-01

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both 'passive' hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  16. Workshop on Interface Phenomena

    CERN Document Server

    Kreuzer, Hans

    1987-01-01

    This book contains the proceedings of the first Workshop on Interface Phenomena, organized jointly by the surface science groups at Dalhousie University and the University of Maine. It was our intention to concentrate on just three topics related to the kinetics of interface reactions which, in our opinion, were frequently obscured unnecessarily in the literature and whose fundamental nature warranted an extensive discussion to help clarify the issues, very much in the spirit of the Discussions of the Faraday Society. Each session (day) saw two principal speakers expounding the different views; the session chairmen were asked to summarize the ensuing discussions. To understand the complexity of interface reactions, paradigms must be formulated to provide a framework for the interpretation of experimen­ tal data and for the construction of theoretical models. Phenomenological approaches have been based on a small number of rate equations for the concentrations or mole numbers of the various species involved i...

  17. Carbon nanotube thermal interfaces on gadolinium foil

    OpenAIRE

    McCarthy, Patrick T.; Marinero, Ernesto E.; Fisher, Timothy S.

    2012-01-01

    We report the thermal behavior of gadolinium foils to be used in magneto thermoelectric generator cells. Magneto thermoelectric generator cell technology exploits the ferromagnetic phase transition of gadolinium to drive the movement of a diaphragm 'shuttle' whose mechanical energy is converted to electrical form and which enhances heat transfer through both conduction and convection. Efficient heat transfer at mechanical interfaces is critical to increase shuttle speed and the commensurate r...

  18. Energy barrier at the N719-dye/CsSnI3 interface for photogenerated holes in dye-sensitized solar cells

    Science.gov (United States)

    Zhang, Jin; Yu, Chunhui; Wang, Lili; Li, Yizhi; Ren, Yuhang; Shum, Kai

    2014-01-01

    This report is to address the question if black γ-polymorph of cesium tin tri-iodide (B-γ-CsSnI3) can be used as a solid-state hole-transport material in the conventional DSSCs with the N719 dye to replace the liquid electrolyte as reported by I. Chung et al. on Nature 485, 486, (2012). Here we demonstrate rigorously that B-γ-CsSnI3 is not energetically possible to collect photogenerated holes because of the large energy barrier at the interface of N719/B-γ-CsSnI3. Therefore, it cannot serve as a hole-transporter for the conventional DSSCs although it is a good hole-conducting material. A solution-based method was employed to synthesize the B-γ-CsSnI3 polycrystalline thin-films used for this work. These thin-films were then characterized by X-ray diffraction, Hall measurements, optical reflection, and photoluminescence (PL). Particularly, spatially resolved PL intensity images were taken after B-γ-CsSnI3 was incorporated in the DSSC structure to insure the material integrity. The means of ultraviolet photoemission spectroscopy (UPS) was used to reveal why B-γ-CsSnI3 could not act as the substitute of liquid electrolyte in the conventional DSSCs. For the completeness, other two related compounds, one is the yellow polymorph of CsSnI3 and other is Cs2SnI6 with tetravalent tin instead of double-valent tin in CsSnI3 were also investigated by UPS. PMID:25378076

  19. Nonlinear optics at interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.K.

    1980-12-01

    Two aspects of surface nonlinear optics are explored in this thesis. The first part is a theoretical and experimental study of nonlinear intraction of surface plasmons and bulk photons at metal-dielectric interfaces. The second part is a demonstration and study of surface enhanced second harmonic generation at rough metal surfaces. A general formulation for nonlinear interaction of surface plasmons at metal-dielectric interfaces is presented and applied to both second and third order nonlinear processes. Experimental results for coherent second and third harmonic generation by surface plasmons and surface coherent antiStokes Raman spectroscopy (CARS) are shown to be in good agreement with the theory.

  20. Modal Interfaces in Hawaii

    Science.gov (United States)

    Wright, E. Alvey

    1974-01-01

    Hawaii, an archipelago where transportation distances are short but the interfaces are many, seeks elimination of modal changes by totally-submerged hydrofoil craft operating at the water surface directly between tourist resort destinations, by dual mode rapid transit vehicles operating directly between the deplaning bridges at Honolulu International Airport and hotel porte-cochere at Waikiki, by demand responsive vehicles for collection and distribution operating on fixed guideways for line haul, and by roll-on/roll-off inter-island ferries for all models of manually operated ground vehicles. The paper also describes facilitation of unavoidable interfaces by innovative sub-systems.

  1. CAMAC to GPIB interface

    International Nuclear Information System (INIS)

    A CAMAC module developed at the Los Alamos Scientific Laboratory allows any device conforming to the GPIB standard to be connected to a CAMAC system. This module incorporates a microprocessor to control up to 14 GPIB-compatible instruments using a restricted set of CAMAC F-N-A commands. The marriage of a device-independent bus (IEEE Standard 488-1975) to a computer-independent bus (IEEE Standard 583-1975) provides a general method for interfacing a system of programmable instruments to any computer. This module is being used to interface a variety of interactive devices on a control console to a control computer

  2. UIL -User Interface Language

    CERN Document Server

    Lewis, J; CERN. Geneva

    1990-01-01

    Some widget examples, widget categories, the push button widget, menus, the FORM widget, using UIL for an application program, the MOTIF Resource Manager (MRM), execution thread of an application using UIL and MRM, opening hierarchies, binding UIL names to application addresses, fetching widget hierarchies and managing them, changing widget resources using UIL and MRM, fetching literal values from the UID file. Introduction to the User Interface Language, defining a user interface, advantages of using UIL, accessing UID files from the application, UIL Syntax, the UIL module structure, defining a widget instance hierarchy, declaration of literals colors, icons, fonts

  3. Interfacing to accelerator instrumentation

    International Nuclear Information System (INIS)

    As the sensory system for an accelerator, the beam instrumentation provides a tremendous amount of diagnostic information. Access to this information can vary from periodic spot checks by operators to high bandwidth data acquisition during studies. In this paper, example applications will illustrate the requirements on interfaces between the control system and the instrumentation hardware. A survey of the major accelerator facilities will identify the most popular interface standards. The impact of developments such as isochronous protocols and embedded digital signal processing will also be discussed

  4. Distributed User Interfaces

    CERN Document Server

    Gallud, Jose A; Penichet, Victor M R

    2011-01-01

    The recent advances in display technologies and mobile devices is having an important effect on the way users interact with all kinds of devices (computers, mobile devices, laptops, tablets, and so on). These are opening up new possibilities for interaction, including the distribution of the UI (User Interface) amongst different devices, and implies that the UI can be split and composed, moved, copied or cloned among devices running the same or different operating systems. These new ways of manipulating the UI are considered under the emerging topic of Distributed User Interfaces (DUIs). DUIs

  5. Unstable nonlocal interface dynamics.

    Science.gov (United States)

    Nicoli, Matteo; Cuerno, Rodolfo; Castro, Mario

    2009-06-26

    Nonlocal effects occur in many nonequilibrium interfaces, due to diverse physical mechanisms like diffusive, ballistic, or anomalous transport, with examples from flame fronts to thin films. While dimensional analysis describes stable nonlocal interfaces, we show the morphologically unstable condition to be nontrivial. This is the case for a family of stochastic equations of experimental relevance, paradigmatically including the Michelson-Sivashinsky system. For a whole parameter range, the asymptotic dynamics is scale invariant with dimension-independent exponents reflecting a hidden Galilean symmetry. The usual Kardar-Parisi-Zhang nonlinearity, albeit irrelevant in that parameter range, plays a key role in this behavior. PMID:19659099

  6. Advanced Power Electronic Interfaces for Distributed Energy Systems Part 1: Systems and Topologies

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, W.; Chakraborty, S.; Kroposki, B.; Thomas, H.

    2008-03-01

    This report summarizes power electronic interfaces for DE applications and the topologies needed for advanced power electronic interfaces. It focuses on photovoltaic, wind, microturbine, fuel cell, internal combustion engine, battery storage, and flywheel storage systems.

  7. Site-specific, cross-sectional imaging of biomaterials and the cell/biomaterial interface using focused ion beam/scanning electron microscopy

    International Nuclear Information System (INIS)

    Focused ion beam / scanning electron microscopy (FIBSEM) procedures are examined for the sectioning of biological cell / biomedical implant materials. Conventional site-specific lift-out techniques enable the structural characterisation of hydroxyapatite/Ti coatings. Cryo-FIBSEM procedures, as used to investigate human osteoblasts/ hydroxyapatite/Ti structures, emphasise the need for the repeated deposition of coating layers to protect such delicate structures and to minimise beam curtaining effects.

  8. Second-harmonic generation of biological interfaces: probing the membrane protein bacteriorhodopsin and imaging membrane potential around GFP molecules at specific sites in neuronal cells of C. elegans

    Science.gov (United States)

    Lewis, Aaron; Khatchatouriants, Artium; Treinin, Millet; Chen, Zhongping; Peleg, Gadi; Friedman, Noga; Bouevitch, Oleg; Rothman, Zvi; Loew, Leslie; Sheres, Mordechai

    1999-07-01

    Second-harmonic generation (SHG) is applied to problems of probing membrane proteins and functionally imaging around selective sites and at single molecules in biological membranes. The membrane protein bacteriorhodopsin (bR) has been shown to have large second-harmonic (SH) intensities that are modulated by protein/retinylidene chromophore interactions. The nonlinear optical properties of model compounds, which simulate these protein chromophore interactions in retinal proteins, are studied in this work by surface SHG and by hyper-Rayleigh scattering. Our results indicate that non-conjugated charges and hydrogen bonding effects have a large effect on the molecular hyperpolarizability of the retinal chromophore. However, mbR, the model system studies suggest that polarizable amino acids strongly affect the vertically excited state of the retinylidene chromophore and appear to play the major role in the observed protein enhancement (>50%) of the retinylidene chromophore molecular hyperpolarizability and associated induced dipole. Furthermore, the data provide insights on emulating these interactions for the design of organic nonlinear optical materials. Our studies have also led to the development of dyes with large SH intensities that can be embedded in cell membranes and can functionally image membrane potential. Single molecules of such dyes in selected single molecular regions of a cell membrane have been detected. SHG from green fluorescent protein (GFP) selectively expressed in concert with a specific protein in neuronal cells in a transgenic form of the worm C. elegans is also reported. The membrane potential around the GFP molecules expressed in these cells has been imaged with SHG in live animals.

  9. Facile realization of efficient blocking from ZnO/TiO2 mismatch interface in dye-sensitized solar cells and precise microscopic modeling adapted by circuit analysis

    Science.gov (United States)

    Ameri, Mohsen; Samavat, Feridoun; Mohajerani, Ezeddin; Fathollahi, Mohammad-Reza

    2016-06-01

    In the present research, the effect of \\text{ZnO} -based blocking layers on the operational features of \\text{Ti}{{\\text{O}}2} -based dye-sensitized solar cells is investigated. A facile solution-based coating method is applied to prepare an interfacial highly transparent \\text{ZnO} compact blocking layer (CBL) to enhance the efficiency of dye-sensitized solar cells. Different precursor molar concentration were tested to find the optimum concentration. Optical and electrical measurements were carried out to confirm the operation of the CBLs. Morphological characterizations were performed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to investigate the structure of the compact layers. We have also developed a set of modeling procedures to extract the effective electrical parameters including the parasitic resistances and charged carrier profiles to investigate the effect of CBLs on the dye-sensitized solar cell (DSSC) performance. The adopted modeling approach should establish a versatile framework for diagnosis of DSSCs and facilitates the exploration of critical factors influencing device performance.

  10. Electron Barrier Formation at the Organic-Back Contact Interface is the First Step in Thermal Degradation of Polymer Solar Cells

    KAUST Repository

    Sachs-Quintana, I. T.

    2014-03-24

    Long-term stability of polymer solar cells is determined by many factors, one of which is thermal stability. Although many thermal stability studies occur far beyond the operating temperature of a solar cell which is almost always less than 65 °C, thermal degradation is studied at temperatures that the solar cell would encounter in real-world operating conditions. At these temperatures, movement of the polymer and fullerenes, along with adhesion of the polymer to the back contact, creates a barrier for electron extraction. The polymer barrier can be removed and the performance can be restored by peeling off the electrode and depositing a new one. X-ray photoelectron spectroscopy measurements reveal a larger amount of polymer adhered to electrodes peeled from aged devices than electrodes peeled from fresh devices. The degradation caused by hole-transporting polymer adhering to the electrode can be suppressed by using an inverted device where instead of electrons, holes are extracted at the back metal electrode. The problem can be ultimately eliminated by choosing a polymer with a high glass transition temperature. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Designing groundwater visualization interfaces

    OpenAIRE

    Médard De Chardon, Cyrille

    2009-01-01

    Groundwater systems are inherently complex owing to their three-dimensional nature. The impacts of land use activities on groundwater quality and quantity, groundwater pumping, and the interaction of groundwater with surface waters are fundamental hydrogeologic concepts that require effective communication strategies. Using interactive visual interfaces may improve upon current educational techniques and encourage increased public participation in groundwater protection, conservation, and man...

  12. Photochemistry at Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Eisenthal, Kenneth B

    2015-02-24

    We have advanced our capabilities to investigate ultrafast excited state dynamics at a liquid interface using a pump to excite molecules to higher electronic states and then probe the subsequent time evolution of the interfacial molecules with femtosecond time delayed vibrational SFG.

  13. The Liquid Vapour Interface

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1985-01-01

    In this short review we are concerned with the density variation across the liquid-vapour interface, i.e. from the bulk density of the liquid to the essentially zero density of the vapour phase. This density variation can in principle be determined from the deviation of the reflectivity from...

  14. Semantic form as interface

    OpenAIRE

    Bierwisch, Manfred

    2009-01-01

    The term interface had a remarkable career over the past several decades, motivated largely by its use in computer science. Although the concept of a "surface common to two areas" (Oxford Advanced Learner's Dictionary, 1980) is intuitively clear enough, the range of its application is not very sharp and well defined, a "common surface" is open to a wide range of interpretations.

  15. Photovoltaics module interface: General purpose primers

    Science.gov (United States)

    Boerio, J.

    1985-01-01

    The interfacial chemistry established between ethylene vinyl acetate (EVA) and the aluminized back surface of commercial solar cells was observed experimentally. The technique employed is called Fourier Transform Infrared (FTIR) spectroscopy, with the infrared signal being reflected back from the aluminum surface through the EVA film. Reflection infrared (IR) spectra are given and attention is drawn to the specific IR peak at 1080/cm which forms on hydrolytic aging of the EVA/aluminum system. With this fundamental finding, and the workable experimental techniques, candidate silane coupling agents are employed at the interface, and their effects on eliminating or slowing hydrolytic aging of the EVA/aluminum interface are monitored.

  16. Development of a methodology for the propagation of 'Calcutta 4' (AA) and plantain genotypes from embryogenic cell suspensions and its interface with mutation breeding

    International Nuclear Information System (INIS)

    Bananas and plantains represent a major staple food for many millions of people in the tropics and subtropics. In Cuba, this crop constitutes a high priority of the national food program because of its capacity of producing fruit all year round, high demand and diversity of use, however, Black Sigatoka disease, caused by the leaf pathogen Mycosphaerella fijiensis, and pests and stress climatic conditions, has resulted in significant yield losses in this culture, which increases the production costs considerably. Somatic embryogenesis combined with mutation induction into in vitro culture mutations has not been studied in depth probably due to the low plant regeneration percentage of different Musa genotypes. Taking into consideration, the previous information following research objects are being developed: to develop a new methodology for developing somatic embryogenesis in different cultivar AAB, and cv. 'Calcutta 4', to develop a methodology for mutation induction with irradiations gamma rays to embryogenic cell suspensions and study anther culture of diploid cultivars. The genetic stability of plants obtained via embryogenesis through embryogenic cell suspensions showed the possibility to use the new methodology for developing somatic embryogenesis in different cultivar. From the results obtained for each cultivar, it is recommended to irradiate cv. 'Calcutta 4' at 50 Gy and cv. 'CEMSA 3/4' at 80 Gy. Irradiations with gamma rays to embryogenic cell suspensions resulted in a shorter stature in regenerated plants. Besides, plants of French plantain type were obtained from cultivar CEMSA 3/4. In Calcutta 4 the irradiation effect caused colour changes in plant pseudo-stems, and also deformed leaves were shown, but did not cause changes in the cultivar susceptibility to Black Sigatoka disease. In anther culture of diploid, callus induced from the state of uninuclate development was higher in relation to the other states studied and the regeneration plants are in

  17. Nitric oxide gas phase release in human small airway epithelial cells

    Directory of Open Access Journals (Sweden)

    Suresh Vinod

    2009-01-01

    Full Text Available Abstract Background Asthma is a chronic airway inflammatory disease characterized by an imbalance in both Th1 and Th2 cytokines. Exhaled nitric oxide (NO is elevated in asthma, and is a potentially useful non-invasive marker of airway inflammation. However, the origin and underlying mechanisms of intersubject variability of exhaled NO are not yet fully understood. We have previously described NO gas phase release from normal human bronchial epithelial cells (NHBEs, tracheal origin. However, smaller airways are the major site of morbidity in asthma. We hypothesized that IL-13 or cytomix (IL-1β, TNF-α, and IFN-γ stimulation of differentiated small airway epithelial cells (SAECs, generation 10–12 and A549 cells (model cell line of alveolar type II cells in culture would enhance NO gas phase release. Methods Confluent monolayers of SAECs and A549 cells were cultured in Transwell plates and SAECs were allowed to differentiate into ciliated and mucus producing cells at an air-liquid interface. The cells were then stimulated with IL-13 (10 ng/mL or cytomix (10 ng/mL for each cytokine. Gas phase NO release in the headspace air over the cells was measured for 48 hours using a chemiluminescence analyzer. Results In contrast to our previous result in NHBE, baseline NO release from SAECs and A549 is negligible. However, NO release is significantly increased by cytomix (0.51 ± 0.18 and 0.29 ± 0.20 pl.s-1.cm-2, respectively reaching a peak at approximately 10 hours. iNOS protein expression increases in a consistent pattern both temporally and in magnitude. In contrast, IL-13 only modestly increases NO release in SAECs reaching a peak (0.06 ± 0.03 pl.s-1.cm-2 more slowly (30 to 48 hours, and does not alter NO release in A549 cells. Conclusion We conclude that the airway epithelium is a probable source of NO in the exhaled breath, and intersubject variability may be due, in part, to variability in the type (Th1 vs Th2 and location (large vs small airway

  18. PREFACE: Water at interfaces Water at interfaces

    Science.gov (United States)

    Gallo, P.; Rovere, M.

    2010-07-01

    This special issue is devoted to illustrating important aspects and significant results in the field of modeling and simulation of water at interfaces with solutes or with confining substrates, focusing on a range of temperatures from ambient to supercooled. Understanding the behavior of water, in contact with different substrates and/or in solutions, is of pivotal importance for a wide range of applications in physics, chemistry and biochemistry. Simulations of confined and/or interfacial water are also relevant for testing how different its behavior is with respect to bulk water. Simulations and modeling in this field are of particular importance when studying supercooled regions where water shows anomalous properties. These considerations motivated the organization of a workshop at CECAM in the summer of 2009 which aimed to bring together scientists working with computer simulations on the properties of water in various environments with different methodologies. In this special issue, we collected a variety of interesting contributions from some of the speakers of the workshop. We have roughly classified the contributions into four groups. The papers of the first group address the properties of interfacial and confined water upon supercooling in an effort to understand the relation with anomalous behavior of supercooled bulk water. The second group deals with the specific problem of solvation. The next group deals with water in different environments by considering problems of great importance in technological and biological applications. Finally, the last group deals with quantum mechanical calculations related to the role of water in chemical processes. The first group of papers is introduced by the general paper of Stanley et al. The authors discuss recent progress in understanding the anomalies of water in bulk, nanoconfined, and biological environments. They present evidence that liquid water may display 'polymorphism', a property that can be present in

  19. Easy-to-use interface

    Energy Technology Data Exchange (ETDEWEB)

    Blattner, M M; Blattner, D O; Tong, Y

    1999-04-01

    Easy-to-use interfaces are a class of interfaces that fall between public access interfaces and graphical user interfaces in usability and cognitive difficulty. We describe characteristics of easy-to-use interfaces by the properties of four dimensions: selection, navigation, direct manipulation, and contextual metaphors. Another constraint we introduced was to include as little text as possible, and what text we have will be in at least four languages. Formative evaluations were conducted to identify and isolate these characteristics. Our application is a visual interface for a home automation system intended for a diverse set of users. The design will be expanded to accommodate the visually disabled in the near future.

  20. Easy-to-use interface

    International Nuclear Information System (INIS)

    Easy-to-use interfaces are a class of interfaces that fall between public access interfaces and graphical user interfaces in usability and cognitive difficulty. We describe characteristics of easy-to-use interfaces by the properties of four dimensions: selection, navigation, direct manipulation, and contextual metaphors. Another constraint we introduced was to include as little text as possible, and what text we have will be in at least four languages. Formative evaluations were conducted to identify and isolate these characteristics. Our application is a visual interface for a home automation system intended for a diverse set of users. The design will be expanded to accommodate the visually disabled in the near future

  1. Science at the interface

    International Nuclear Information System (INIS)

    Laboratories have advantages One of these is that a laboratory science does not have to put up with its objects of investigation as they occur in nature. First, it does not need to accommodate a natural object where it is, anchored in a natural environment; laboratory sciences bring objects inside and manipulate them on their own terms in the lab. Second, a laboratory science need not accommodate an event when it happens; it can dispense with natural cycles of occurrence and make events happen frequently enough for continuous study. Third, a laboratory science does not have to put up with an object as it is; it can substitute transformed and partial versions. Dissociating natural objects from their environment and re-configuring them in the lab is not simple, but it has epistemic advantages when it can be accomplished. For example, the objects of interest tend to become miniaturized (cell cultures rather than whole plants, image measurements rather than cosmological objects), they tend to become continually available in laboratories world-wide for inquiry, and planetary and stellar time scales are replaced by the time scales of the social order. Laboratories also impose conditions, for example sharp boundaries between the internal and the external world. Most laboratories in the natural sciences have procedures (and walls) to fend off unwanted transgressions of objects from the natural and human environment which they see as potential contaminants. A wild-type mouse in a molecular biology lab is not, for example, an animal caught in the wild. It is a special mouse strain inbred over many generations in breeding labs to serve as a control in relevant experiments. Animals that live in the wild (or in the buildings where labs are located) are strictly prohibited from entering a lab facility as potential disease carriers and pollutants. Laboratories, then, are not only specialized places, they are places that set up barriers against the environment and attempt to raise

  2. Effective elastic moduli and interface effects of nano- crystalline materials

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Many properties of nanocrystalline materials are associated with interface effects. Based on their microstructural features, the influence of interfaces on the effective elastic property of nanocrystalline materials is investigated. First, the Mori-Tanaka method is employed to determine the overall effective elastic moduli by considering a nanocrystalline material as a binary composite solid consisting of a crystal or inclusion phase with regular lattice connected by an amorphous-like interface or matrix phase. The effects of strain gradients are then examined on the effective elastic property by using the strain gradient theory to analyze a representative unit cell. Two interface mechanisms are elucidated that influence the effective stiffness and other mechanical properties of materials. One is the softening effect due to the distorted atomic structures and the increased atomic spacings in interface regions, and the other is the baffling effect due to the existence of boundary layers near interfaces.

  3. Design of a bioelectrocatalytic electrode interface for oxygen reduction in biofuel cells based on a specifically adapted Os-complex containing redox polymer with entrapped Trametes hirsuta laccase

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, Yvonne; Guschin, Dmitrii A.; Eckhard, Kathrin; Schuhmann, Wolfgang [Analytische Chemie - Elektroanalytik and Sensorik, Ruhr-Universitaet Bochum, Universitaetsstr. 150, D-44780 Bochum (Germany); Shleev, Sergey [Biomedical Laboratory Science, Faculty of Health and Society, Malmoe University, Soedra Foerstadsgatan 101, SE-20506 Malmoe (Sweden)

    2010-05-15

    The design of the coordination shell of an Os-complex and its integration within an electrodeposition polymer enables fast electron transfer between an electrode and a polymer entrapped high-potential laccase from the basidiomycete Trametes hirsuta. The redox potential of the Os{sup 3+/2+}-centre tethered to the polymer backbone (+ 720 mV vs. NHE) is perfectly matching the potential of the enzyme (+ 780 mV vs. NHE at pH 6.5). The laccase and the Os-complex modified anodic electrodeposition polymer were simultaneously precipitated on the surface of a glassy carbon electrode by means of a pH-shift to 2.5. The modified electrode was investigated with respect to biocatalytic O{sub 2} reduction to H{sub 2}O. The proposed modified electrode has potential applications as biofuel cell cathode. (author)

  4. Poly (3,4-ethylenedioxythiophene) promotes direct electron transfer at the interface between Shewanella loihica and the anode in a microbial fuel cell

    Science.gov (United States)

    Liu, Xing; Wu, Wenguo; Gu, Zhongze

    2015-03-01

    Anode modification is an effective method for enhancing extracellular electron transportation and improving the power density of microbial fuel cells (MFCs). In this study, a new conductive polymer called poly (3,4-ethylenedioxythiophene) (PEDOT) is electrochemically polymerized to modify the anode. The surface of the electrochemically polymerized PEDOT layer has a widespread porous structure. Both the anode electrochemical discharge experiment and MFC discharge test demonstrate the improved performance of the PEDOT-modified anode compared with a plain anode. Cyclic voltammetry and electrochemical impedance spectroscopy analyses show that the PEDOT modification increases the availability of redox active sites and reduces the interfacial electron transfer resistance of the anode. Compared with the unmodified anode, the PEDOT anodic modification improves the power density by 43%-140 mW m-2. Possible mechanisms are proposed to help understand the function of the PEDOT-modified anodic layer.

  5. Politics at the interface

    DEFF Research Database (Denmark)

    Kannabiran, Gobinaath; Petersen, Marianne Graves

    2010-01-01

    At the birth of participatory design, there was a strong political consciousness surrounding the design of new technology, the design process in particular, establishing a rich set of methods and tools for user-centered design. Today, the term design has extended its scope of concern beyond...... the process of design and into how users interact with the designed product on a day-to-day basis. This paper is an attempt to call to attention the need for a new set of methods, attitudes and approaches, along with the existing, to discuss, analyze and reflect upon the politics at the interface....... By presenting a critical analysis of two design cases, we elicit the importance of such an agenda and the implications for design in doing so. We use the Foucauldian notion of power to analyze the power relationships in these two cases and to articulate the politics at the interface. We conclude by emphasizing...

  6. Urban Media and Interfaces

    DEFF Research Database (Denmark)

    Halse, Joachim; Damsholt, Tine

    2013-01-01

    For ten weeks in 2013, nineteen eclectic students from Anthropology, Ethnology and Design formed cross-disciplinary teams to research existing practices and possible futures in Blågården. Social media is radically changing how urban space is explored, experienced and communicated. For example......, Wonderful Copenhagen and Socialsquare jointly raise these questions: What is the role of social media as interface between the area around Blågårds Plads, its local communities and (potential) visitors, considering perspectives of security, control and planning? What are the challenges and opportunities...... pertaining to local knowledge and social media? Our students' projects are displayed for your enjoyment and exploration! (http://cargocollective.com/umai/About-Urban-Media-and-Interfaces) Tine Damsholt, Karen Waltorp & Joachim Halse – Faculties of Social Sciences, Humanities and Design...

  7. User interface design considerations

    DEFF Research Database (Denmark)

    Andersen, Simon Engedal; Jakobsen, Arne; Rasmussen, Bjarne D.

    1999-01-01

    user interface of EESCoolTools these issues led to a series of simulation tools each with a specific purpose and a carefully selected set of input and output variables. To allow a more wide range of questions to be answered by the same model, the user can change between different sets of input and...... have a lot of flexibility in choosing input variables and in assigning values of parameters....

  8. Computer Interfaced Gauss Meter

    OpenAIRE

    Lo, Steven; Lai, Alan; Dao, Christine; Hung Vu, Hung

    2013-01-01

    Goal: Gauss Meter Model X01.  Gauss meter model X01 is the hand-held device designed to meet the needs of magnetic industry to measure magnetic fields accurately, provided high-end functionality and performance in an affordable laptop instrument. Magnet testing and sorting have never been easier. Additional features including calculating magnetic field intensity versus time and displaying magnetic field direction on a Graphical User Interface on Computer.  Introduction/Background:  Magnetic f...

  9. Practical Brain Computer Interfacing

    OpenAIRE

    Valbuena Varon, Diana Alexandra

    2011-01-01

    A brain-computer interface (BCI) is a communication system that enables users to voluntary send messages or commands without movement. The classical goal of BCI research is to support communication and control for users with impaired communication due to illness or injury. Typical BCI applications are the operation of computer cursors, spelling programs or external devices, such as wheelchairs, robots and neural prostheses. The user sends modulated information to the BCI by engaging in mental...

  10. Standard interface file handbook

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, A.; Huria, H.C. [Cincinnati Univ., OH (United States)

    1992-10-01

    This handbook documents many of the standard interface file formats that have been adopted by the US Department of Energy to facilitate communications between and portability of, various large reactor physics and radiation transport software packages. The emphasis is on those files needed for use of the VENTURE/PC diffusion-depletion code system. File structures, contents and some practical advice on use of the various files are provided.

  11. SNE Industrial Fieldbus Interface

    Science.gov (United States)

    Lucena, Angel; Raines, Matthew; Oostdyk, Rebecca; Mata, Carlos

    2011-01-01

    Programmable logic controllers (PLCs) have very limited diagnostic and no prognostic capabilities, while current smart sensor designs do not have the capability to communicate over Fieldbus networks. The aim is to interface smart sensors with PLCs so that health and status information, such as failure mode identification and measurement tolerance, can be communicated via an industrial Fieldbus such as ControlNet. The SNE Industrial Fieldbus Interface (SIFI) is an embedded device that acts as a communication module in a networked smart sensor. The purpose is to enable a smart sensor to communicate health and status information to other devices, such as PLCs, via an industrial Fieldbus networking protocol. The SNE (Smart Network Element) is attached to a commercial off-the-shelf Any bus-S interface module through the SIFI. Numerous Anybus-S modules are available, each one designed to interface with a specific Fieldbus. Development of the SIFI focused on communications using the ControlNet protocol, but any of the Anybus-S modules can be used. The SIFI communicates with the Any-bus module via a data buffer and mailbox system on the Anybus module, and supplies power to the module. The Anybus module transmits and receives data on the Fieldbus using the proper protocol. The SIFI is intended to be connected to other existing SNE modules in order to monitor the health and status of a transducer. The SIFI can also monitor aspects of its own health using an onboard watchdog timer and voltage monitors. The SIFI also has the hardware to drive a touchscreen LCD (liquid crystal display) unit for manual configuration and status monitoring.

  12. Adaptive Brain Interfaces

    OpenAIRE

    Millán, José del R.

    2003-01-01

    Severely disabled people are largely excluded from the benefits information and communication technologies have brought to our industries, economies, appliances, and general quality of life. But what if that technology would allow them to communicate their wishes or control electronic devices directly through their thoughts alone? This is the goal and promise of the Adaptive Brain Interfaces (ABI) project, which aims to augment natural human capabilities by enabling people to interact with co...

  13. MAN – MACHINE INTERFACE

    OpenAIRE

    S.Bhuvaneswari; R.Hemachandran; Suman Kumar Pandey

    2012-01-01

    Agents trained by learning techniques provide a powerful approximation of state spaces in games that are too large for naive approaches. In the study Genetic Algorithms and Manual Interface was implemented and used to train agents for the board game LUDO. The state space of LUDO is generalized to a small set and encoded to suit the different techniques. The impact of variables and tactics applied in training are determined. Agents based on the techniques performed satisfactory aga...

  14. Standard interface file handbook

    International Nuclear Information System (INIS)

    This handbook documents many of the standard interface file formats that have been adopted by the US Department of Energy to facilitate communications between and portability of, various large reactor physics and radiation transport software packages. The emphasis is on those files needed for use of the VENTURE/PC diffusion-depletion code system. File structures, contents and some practical advice on use of the various files are provided

  15. Interface Microstructures in Concrete

    Directory of Open Access Journals (Sweden)

    Puertas, Francisca

    1991-03-01

    Full Text Available This paper constitutes a compilation as well as an interpretation of the present state of knowledge about the different microstructures developed in the interface areas of concrete, that is, the cement paste-aggregates, the cement paste-reinforcement, the cement paste-fiber, etc. The Chemical reactions taking place in interface areas, the development and morphology of such areas and their strength ^since interfaces are taken as the weakest points of concrete are the aspects dealt with in some detail in this work.

    El presente trabajo constituye un resumen y también una interpretación del estado actual del conocimiento respecto de las diferentes microestructuras que se desarrollan en las zonas interfaciales de los hormigones, es decir: pasta de cemento-áridos, pasta de cemento-armaduras, pasta de cemento-fibras, etc. Las reacciones químicas que tienen lugar en la zona interfacial, el desarrollo y morfología de dicha zona y su resistencia (las interfases se consideran como uno de los puntos débiles del hormigón son los aspectos que con cierto detalle se tratan en el trabajo.

  16. Assessing Electromyographic Interfaces

    Directory of Open Access Journals (Sweden)

    Joaquim Armando Pires Jorge

    2009-01-01

    Full Text Available Electronic apppliances are increasingly a part of our everyday lives. In particular, mobile devices, with their reduced dimensions with power rivaling desktop computers, have substantially augmented our communication abilities offering instant availability, anywhere, to everyone. These devices have become essential for human communication but also include a more comprehensive tool set to support productivity and leisure applications.However, the many applications commonly available are not adapted to people with special needs. Rather, most popular devices are targeted at teenagers or young adults with excellent eyesight and coordination. What is worse, most of the commonly used assistive control interfaces are not available in a mobile environment where user's position, accommodation and capacities can vary even widely.To try and address people with special needs new approaches and techniques are sorely needed. This paper presents a control interface to allow tetraplegic users to interact with electronic devices. Our method uses myographic information (Electromyography or EMG collected from residually controlled body areas. User evaluations validate electromyography as a daily wearable interface. In particular our results show that EMG can be used even in mobility contexts.

  17. Reduced interface recombination in Cu{sub 2}ZnSnS{sub 4} solar cells with atomic layer deposition Zn{sub 1−x}Sn{sub x}O{sub y} buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    Platzer-Björkman, C.; Frisk, C.; Larsen, J. K.; Ericson, T.; Li, S.-Y.; Scragg, J. J. S.; Keller, J.; Larsson, F.; Törndahl, T. [Ångström Solar Center, Solid State Electronics, Engineering Sciences, Uppsala University, Box 534, 75121 Uppsala (Sweden)

    2015-12-14

    Cu{sub 2}ZnSnS{sub 4} (CZTS) solar cells typically include a CdS buffer layer in between the CZTS and ZnO front contact. For sulfide CZTS, with a bandgap around 1.5 eV, the band alignment between CZTS and CdS is not ideal (“cliff-like”), which enhances interface recombination. In this work, we show how a Zn{sub 1−x}Sn{sub x}O{sub y} (ZTO) buffer layer can replace CdS, resulting in improved open circuit voltages (V{sub oc}) for CZTS devices. The ZTO is deposited by atomic layer deposition (ALD), with a process previously developed for Cu(In,Ga)Se{sub 2} solar cells. By varying the ALD process temperature, the position of the conduction band minimum of the ZTO is varied in relation to that of CZTS. A ZTO process at 95 °C is found to give higher V{sub oc} and efficiency as compared with the CdS reference devices. For a ZTO process at 120 °C, where the conduction band alignment is expected to be the same as for CdS, the V{sub oc} and efficiency is similar to the CdS reference. Further increase in conduction band minimum by lowering the deposition temperature to 80 °C shows blocking of forward current and reduced fill factor, consistent with barrier formation at the junction. Temperature-dependent current voltage analysis gives an activation energy for recombination of 1.36 eV for the best ZTO device compared with 0.98 eV for CdS. We argue that the V{sub oc} of the best ZTO devices is limited by bulk recombination, in agreement with a room temperature photoluminescence peak at around 1.3 eV for both devices, while the CdS device is limited by interface recombination.

  18. An Approach to Interface Synthesis

    DEFF Research Database (Denmark)

    Madsen, Jan; Hald, Bjarne

    1995-01-01

    Presents a novel interface synthesis approach based on a one-sided interface description. Whereas most other approaches consider interface synthesis as optimizing a channel to existing client/server modules, we consider the interface synthesis as part of the client/server module synthesis (which...... may contain the re-use of existing modules). The interface synthesis approach describes the basic transformations needed to transform the server interface description into an interface description on the client side of the communication medium. The synthesis approach is illustrated through a point......-to-point communication, but is applicable to synthesis of a multiple client/server environment. The interface description is based on a formalization of communication events....

  19. Small-angle reflectometry of milk protein (β -casein) at the air/serum interface and its conformational changes due to fat content and temperature

    International Nuclear Information System (INIS)

    Full text: The surface structure of dispersed emulsions play a key role in stability of the system. Proteins being one of the most important surface-active components in foods stabilise interfaces by self-interaction, resulting in a stiff visco-elastic adsorbed layer. These interactions are sensitive to disruptive effects of lipids. Previous kinetics studies by the group 1 using the X-ray reflectivity method to investigate the surface adsorption of milk proteins indicate that β -casein had a stronger affinity for the air-liquid interface compared to whey proteins. It has been shown that initially a dense protein layer, with the thickness of 20 Angstroms is formed then a second more diffuse layer with lower volume density of protein follows. Here we report the conformational changes (with particular emphasise on the β -casein tail) occurred at the air-milk serum interface due to the effects of milk fat content, temperature and the milk preparation technique (ie homogenisation vs microfluidisation). In the effect of fat content on the adsorption of protein into the interface the key conclusion is that at lower temperatures the surface composition remains unchanged. The compositional changes, however, become significant at room temperature indicating adsorption of less reflective-water-soluble components into the surface layer. Repulsive interactions between casein aggregates are also involved. Microfluidised samples having the advantage of smaller particle size prove to be more stable to fat or temperature effects compared to the corresponding homogenised milks

  20. Effects of acetyl acetone-typed co-adsorbents on the interface charge recombination in dye-sensitized solar cell photoanodes

    International Nuclear Information System (INIS)

    Acetyl acetone and its derivatives, 3-butyl-2,4-pentanedione and 3-phenyl-2, 4-pentanedione are investigated as co-adsorbents of photoelectrodes for dye-sensitized solar cells (DSSC). The DSSC based on 3-phenyl-2,4-pentanedione co-adsorbent shows the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 67.3%, a short-circuit photocurrent density (JSC) of 15.73 mA cm2, an open-circuit photo-voltage (VOC) of 0.74 V and a fill factor (FF) of 0.69, corresponding to an overall conversion efficiency of 8.07% under the standard global AM 1.5 solar light condition. Electrochemical impedance (EIS) data and open-circuit voltage decay (OCVD) data indicate that the electron lifetime is improved by co-adsorption of 3-phenyl-2,4-pentanedione, it is associated with the 3-phenyl-2,4-pentanedione co-adsorbent forms a protect layer of TiO2 which can inhibit the electron recombination efficiently. The results confirm that the acetyl acetone-typed co-adsorbents with less effect on the adsorption of dye, more hydrophobic structure and stronger electron donating ability, such as 3-phenyl-2,4-pentanedione, can improve the performance of DSSC

  1. ITO electrode/photoactive layer interface engineering for efficient inverted polymer solar cells based on P3HT and PCBM using a solution-processed titanium chelate

    International Nuclear Information System (INIS)

    We report efficient inverted polymer solar cells (PSCs) based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) using alcohol-soluble titanium (diisopropoxide) bis (2,4-pentanedionate) (TIPD) as an electron selective layer between the indium tin oxide (ITO) electrode and the photoactive layer. The thermally annealed TIPD layer is highly transparent in the visible range and shows effective electron collection ability. By optimizing the electron-collecting layer, the photoactive layer and the hole-collecting layer, the power conversion efficiency (PCE) of the inverted device with the structure ITO/TIPD/P3HT : PCBM/MoO3/Ag reaches 4.10% under the illumination of AM1.5G, 100 mW cm-2, which is among the highest values for inverted PSCs based on P3HT : PCBM. The PCE of the inverted device is improved in comparison with the conventional device (3.77%) under the same experimental conditions. (paper)

  2. A new titanium biofunctionalized interface based on poly(pyrrole-3-acetic acid) coating: proliferation of osteoblast-like cells and future perspectives.

    Science.gov (United States)

    De Giglio, Elvira; Cometa, Stefania; Calvano, Cosima-Damiana; Sabbatini, Luigia; Zambonin, Pier Giorgio; Colucci, Silvia; Benedetto, Adriana Di; Colaianni, Graziana

    2007-09-01

    In recent years, many procedures based on surface modification have been suggested to improve the biocompatibility and biofunctionality of orthopedic titanium-based implants. In this contest, the development of a new titanium-based biomaterial that could be covalently modified with biologically active molecules (i.e., RGD-peptides, growth factors, etc.) able to improve osteoblasts response was investigated. The strategy followed was based on a preliminary coating of the implant material by an adherent thin polymer film to which bioactive molecules could be grafted exploiting the polymer surface chemical reactivity. In this work, we focused our attention on pyrrole-3-acetic acid (Py-3-acetic), a pyrrole with carboxylic acid substituent, whose electrosynthesis and characterization on titanium substrates were already accomplished and whose potentialities in the design of new biocompatible surfaces are well evident. As first step, the biocompatibility of the electrochemically grown PPy-3-acetic films was investigated performing in vitro tests (adhesion and proliferation) with mouse bone marrow cells. Successively, the availability and reactivity of surface carboxylic groups were tested through the grafting of an aminoacidic residue to PPy-3-acetic films. PMID:17483896

  3. Influence of Electrode Interfaces on the Stability of Perovskite Solar Cells: Reduced Degradation Using MoOx/Al for Hole Collection

    Energy Technology Data Exchange (ETDEWEB)

    Sanehira, Erin M.; Tremolet de Villers, Bertrand J.; Schulz, Philip; Reese, Matthew O.; Ferrere, Suzanne; Zhu, Kai; Lin, Lih Y.; Berry, Joseph J.; Luther, Joseph M.

    2016-07-08

    We investigated and characterized the stability of the power output from methylammonium lead iodide perovskite photovoltaic devices produced with various hole-collecting anode configurations consisting of Au, Ag, MoOx/Au, MoOx/Ag, and MoOx/Al. The unencapsulated devices were operated under constant illumination and constant load conditions in laboratory ambient with periodic current-voltage testing. Although the initial efficiencies of devices were comparable across these configurations, the stability of these devices varied significantly due to subtle differences in the electrode structure. Specifically, we found that devices with MoOx/Al electrodes are more stable than devices with more conventional, and more costly, Au and Ag electrodes. We demonstrate that a thin MoOx layer inhibits decomposition of the perovskite films under illumination in ambient laboratory conditions and greater improvements in device stability are achieved specifically with MoOx/Al electrodes. We investigated the role of the MoOx interlayer in the MoOx/Al electrodes by exploring the effect of relative humidity and the MoOx interlayer thickness on the perovskite solar cell stability.

  4. Study of charge separation and interface formation in a single nanorod CdS–CuxS heterojunction solar cell using Kelvin probe force microscopy

    International Nuclear Information System (INIS)

    In the present investigation, Kelvin probe force microscopy (KPFM) is used to study the charge separation, shift in Fermi level position and interfacial depletion region formation in a single cadmium sulfide (CdS)–copper sulfide (CuxS) nanorod heterojunction fabricated using hydrothermal synthesis and a topotaxial conversion reaction. A detailed analysis of KPFM images in the dark shows work function (or Fermi energy) values of CdS and CuxS regions consistent with the energy band diagram of the CdS–CuxS junction. Under illumination, Fermi energy levels of both the CuxS and CdS shift away from the vacuum level by 0.2 and 0.4 eV, respectively, which is very different from the behaviour expected in the case of a bulk p–n junction. The existence of interfacial regions topographically placed between ITO–CdS and CdS–CuxS with intermediate work function values as well as the observed narrowing of the work function spread under illumination are important for understanding the fundamental process of charge separation and junction formation in semiconductor nanorod solar cells. (paper)

  5. Growth of Cu2O on Ga-doped ZnO and their interface energy alignment for thin film solar cells

    International Nuclear Information System (INIS)

    Cu2O thin films are deposited by direct current reactive magnetron sputtering on borofloat glass and indium tin oxide (ITO) coated glass at room temperature. The effect of oxygen partial pressure on the structures and properties of Cu2O thin films are investigated. We show that oxygen partial pressure is a crucial parameter in achieving pure phases of CuO and Cu2O. Based on this finding, we fabricate heterojunctions of p-type Cu2O with n-type gallium doped ZnO (GZO) on ITO coated glass substrates by pulsed laser deposition for GZO thin films. The energy band alignment for thin films of Cu2O/GZO on ITO glass is characterized using high-resolution x-ray photoelectron spectroscopy. The energy band alignment for the Cu2O/GZO heterojunctions is determined to be type II with a valence band offset of 2.82 eV and shows negligible effects of variation with gallium doping. The higher conduction band of the Cu2O relative to that of GZO in the obtained band alignment shows that the heterojunctions are suitable for solar cell application based on energy levels consideration.

  6. Vibrational spectroscopy at electrified interfaces

    CERN Document Server

    Wieckowski, Andrzej; Braunschweig, Björn

    2013-01-01

    Reviews the latest theory, techniques, and applications Surface vibrational spectroscopy techniques probe the structure and composition of interfaces at the molecular level. Their versatility, coupled with their non-destructive nature, enables in-situ measurements of operating devices and the monitoring of interface-controlled processes under reactive conditions. Vibrational Spectroscopy at Electrified Interfaces explores new and emerging applications of Raman, infrared, and non-linear optical spectroscopy for the study of charged interfaces. The book draws from hu

  7. Progress report (interface segment)

    International Nuclear Information System (INIS)

    Full text: 1. Presentations and status reports. T. Fukahori (JAEA) reported on the plans for the www interface layout. Discussions included which functions were needed for new RIPL-3 web pages. The results are summarized in next section. 2. Layout of the interfaces and retrieval tools and web. RIPL-3 home page will include some description about RIPL-3 and link to the Technical report in pdf-format. The web page for 'mass' segment contains same contents as RIPL-2 except the removal of the information about ground state deformation. The abundance data will be replaced by data from the new BNL wallet card (2005 version). The Q-value calculation tool will be also improved. The 'Nuclear Matter Density' will be renamed 'Nucleon Density Distribution'. 'Levels' segment will be same as before, and the deformation parameters for excited levels will be moved from 'optical' segment and given the name 'deformation'. 'Resonances' segment will be same as before - may be replaced with the new Mughabghab tables. 'Optical' segment will be same as before, and the deformation parameters for excited levels will be moved to 'optical' segment and given the name 'deformation'. The optical model calculation with ECIS and OPTMAN will be considered and double-folding calculation tool will possibly be provided. 'Densities' segment will be same as before, and the plotting programs will be checked. The 3-7 sets of combination of GC, BSFG, GSFM with/without enhancement factors will be given. 'Gamma' segment will be same as before, with addition of MLO and theoretical GDR calculation. 'Fission' segment will be same as before, and 'Exp.' will be renamed. New barrier evaluations will be added, for example, transition (2+) states. The fission spectrum calculation tool (codes and inputs) may be added. The fundamental format will be kept as before. For new items such as deformed 'nucleon density distribution', double-folding potential, evaluated fission barrier (extension into 3 or more) and fission

  8. A Computational Method for Sharp Interface Advection

    CERN Document Server

    Roenby, Johan; Jasak, Hrvoje

    2016-01-01

    We devise a numerical method for passive advection of a surface, such as the interface between two incompressible fluids, across a computational mesh. The method is called isoAdvector, and is developed for general meshes consisting of arbitrary polyhedral cells. The algorithm is based on the volume of fluid (VOF) idea of calculating the volume of one of the fluids transported across the mesh faces during a time step. The novelty of the isoAdvector concept consists in two parts: First, we exploit an isosurface concept for modelling the interface inside cells in a geometric surface reconstruction step. Second, from the reconstructed surface, we model the motion of the face-interface intersection line for a general polygonal face to obtain the time evolution within a time step of the submerged face area. Integrating this submerged area over the time step leads to an accurate estimate for the total volume of fluid transported across the face. The method was tested on simple 2D and 3D interface advection problems ...

  9. Spherical model of growing interfaces

    OpenAIRE

    Henkel, Malte; Durang, Xavier

    2015-01-01

    Building on an analogy between the ageing behaviour of magnetic systems and growing interfaces, the Arcetri model, a new exactly solvable model for growing interfaces is introduced, which shares many properties with the kinetic spherical model. The long-time behaviour of the interface width and of the two-time correlators and responses is analysed. For all dimensions $d\

  10. A Large Interface Model for two-phase CFD

    International Nuclear Information System (INIS)

    Highlights: ► CFD of PTS involves interfaces generally much larger than the computational cells. ► A two-phase model is developed to better take them into account. ► It includes interface recognition, friction, heat and mass transfer. ► The models are written in a three-cell stencil in a wall law-like format. -- Abstract: In the context of the Pressurized Thermal Shock (PTS) studies related to PWR life extension, a two-phase CFD (Eulerian two-field 3D transient) approach has been developed and validated during the last decade. The PTS CFD involves interfaces between liquid and vapour which are generally much larger than the computational cells size: the large interfaces. Special models to deal with them were developed and implemented in the NEPTUNECFD code: it is the Large Interface Model (LIM). It includes large interface recognition, interfacial transfer of momentum (friction), heat and mass transfer with direct contact condensation. The LIM takes into account large interfaces which can be smooth, wavy or rough. The models are written within a three-cell stencil around the large interface position. This stencil is used to calculate, on both the liquid and gas sides, the distance from the first computational cell to the large interface. Both distances are used in the models written in a wall law-like format. Some assumptions made to write the LIM were deduced from the picture given by the experimental data base which was defined for the CFD validation in the context of the PTS issue

  11. Particulate Matter from Both Heavy Fuel Oil and Diesel Fuel Shipping Emissions Show Strong Biological Effects on Human Lung Cells at Realistic and Comparable In Vitro Exposure Conditions

    Science.gov (United States)

    Dilger, Marco; Paur, Hanns-Rudolf; Schlager, Christoph; Mülhopt, Sonja; Diabaté, Silvia; Weiss, Carsten; Stengel, Benjamin; Rabe, Rom; Harndorf, Horst; Torvela, Tiina; Jokiniemi, Jorma K.; Hirvonen, Maija-Riitta; Schmidt-Weber, Carsten; Traidl-Hoffmann, Claudia; BéruBé, Kelly A.; Wlodarczyk, Anna J.; Prytherch, Zoë; Michalke, Bernhard; Krebs, Tobias; Prévôt, André S. H.; Kelbg, Michael; Tiggesbäumker, Josef; Karg, Erwin; Jakobi, Gert; Scholtes, Sorana; Schnelle-Kreis, Jürgen; Lintelmann, Jutta; Matuschek, Georg; Sklorz, Martin; Klingbeil, Sophie; Orasche, Jürgen; Richthammer, Patrick; Müller, Laarnie; Elsasser, Michael; Reda, Ahmed; Gröger, Thomas; Weggler, Benedikt; Schwemer, Theo; Czech, Hendryk; Rüger, Christopher P.; Abbaszade, Gülcin; Radischat, Christian; Hiller, Karsten; Buters, Jeroen T. M.; Dittmar, Gunnar; Zimmermann, Ralf

    2015-01-01

    Background Ship engine emissions are important with regard to lung and cardiovascular diseases especially in coastal regions worldwide. Known cellular responses to combustion particles include oxidative stress and inflammatory signalling. Objectives To provide a molecular link between the chemical and physical characteristics of ship emission particles and the cellular responses they elicit and to identify potentially harmful fractions in shipping emission aerosols. Methods Through an air-liquid interface exposure system, we exposed human lung cells under realistic in vitro conditions to exhaust fumes from a ship engine running on either common heavy fuel oil (HFO) or cleaner-burning diesel fuel (DF). Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling including isotope labelling methods to characterise the lung cell responses. Results The HFO emissions contained high concentrations of toxic compounds such as metals and polycyclic aromatic hydrocarbon, and were higher in particle mass. These compounds were lower in DF emissions, which in turn had higher concentrations of elemental carbon (“soot”). Common cellular reactions included cellular stress responses and endocytosis. Reactions to HFO emissions were dominated by oxidative stress and inflammatory responses, whereas DF emissions induced generally a broader biological response than HFO emissions and affected essential cellular pathways such as energy metabolism, protein synthesis, and chromatin modification. Conclusions Despite a lower content of known toxic compounds, combustion particles from the clean shipping fuel DF influenced several essential pathways of lung cell metabolism more strongly than particles from the unrefined fuel HFO. This might be attributable to a higher soot content in DF. Thus the role of diesel soot, which is a known carcinogen in acute air pollution-induced health effects should be further investigated. For the

  12. Particulate matter from both heavy fuel oil and diesel fuel shipping emissions show strong biological effects on human lung cells at realistic and comparable in vitro exposure conditions.

    Directory of Open Access Journals (Sweden)

    Sebastian Oeder

    Full Text Available Ship engine emissions are important with regard to lung and cardiovascular diseases especially in coastal regions worldwide. Known cellular responses to combustion particles include oxidative stress and inflammatory signalling.To provide a molecular link between the chemical and physical characteristics of ship emission particles and the cellular responses they elicit and to identify potentially harmful fractions in shipping emission aerosols.Through an air-liquid interface exposure system, we exposed human lung cells under realistic in vitro conditions to exhaust fumes from a ship engine running on either common heavy fuel oil (HFO or cleaner-burning diesel fuel (DF. Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling including isotope labelling methods to characterise the lung cell responses.The HFO emissions contained high concentrations of toxic compounds such as metals and polycyclic aromatic hydrocarbon, and were higher in particle mass. These compounds were lower in DF emissions, which in turn had higher concentrations of elemental carbon ("soot". Common cellular reactions included cellular stress responses and endocytosis. Reactions to HFO emissions were dominated by oxidative stress and inflammatory responses, whereas DF emissions induced generally a broader biological response than HFO emissions and affected essential cellular pathways such as energy metabolism, protein synthesis, and chromatin modification.Despite a lower content of known toxic compounds, combustion particles from the clean shipping fuel DF influenced several essential pathways of lung cell metabolism more strongly than particles from the unrefined fuel HFO. This might be attributable to a higher soot content in DF. Thus the role of diesel soot, which is a known carcinogen in acute air pollution-induced health effects should be further investigated. For the use of HFO and DF we recommend a

  13. Quasi-reflected interface conditions for variational nodal lattice calculations

    International Nuclear Information System (INIS)

    Quasi-reflected interface conditions are formulated to partially decouple periodic lattice effects from the pin-cell to pin-cell flux variation in the finite sub-element form of the variational nodal code VARIANT. With fuel-coolant homogenization eliminated, the interface variables that couple pin-cell sized nodes are divided into low-order and high-order spherical harmonic terms, and reflected interface conditions are applied to the high-order terms. This approach dramatically reduces the dimension of the resulting response matrices and leads to sharply reduced memory and CPU requirements for the solution of the resulting response matrix equations. The method is applied to a two-dimensional OECD/NEA PWR benchmark containing MOX and UO2 fuel assemblies. Results indicate that the quasi-reflected interface conditions result in very little loss of accuracy relative to the corresponding full spherical harmonics expansion. (authors)

  14. A way for studying the impact of PEDOT:PSS interface layer on carrier transport in PCDTBT:PC71BM bulk hetero junction solar cells by electric field induced optical second harmonic generation measurement

    International Nuclear Information System (INIS)

    Electric-field-induced optical second-harmonic generation (EFISHG) measurement was employed to study the impact of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) interface layer on the carrier transport mechanism of the PCDTBT:PC71BM bulk heterojunction (BHJ) organic solar cells (OSCs). We revealed that the electric fields in the PCDTBT and PC71BM were allowed to be measured individually by choosing fundamental laser wavelengths of 1000 nm and 1060 nm, respectively, in dark and under illumination. The results showed that the direction of the internal electric fields in the PCDTBT:PC71BM BHJ layer is reversed by introducing the PEDOT:PSS layer, and this results in longer electron transport time in the BHJ layer. We conclude that TR-EFISHG can be used as a novel way for studying the impact of interfacial layer on the transport of electrons and holes in the bulk-heterojunction OSCs

  15. Challenges in the simulation of dye-sensitized ZnO solar cells: quantum confinement, alignment of energy levels and excited state nature at the dye/semiconductor interface.

    Science.gov (United States)

    Amat, Anna; De Angelis, Filippo

    2012-08-14

    We report a first principles density functional theory/time-dependent density functional theory (DFT/TDDFT) computational investigation on a prototypical perylene dye anchored to realistic ZnO nanostructures, approaching the size of the ZnO nanowires used in dye-sensitized solar cells devices. DFT calculations were performed on (ZnO)(n) clusters of increasing size, with n up to 222, of 1.3 × 1.5 × 3.4 nm dimensions, and for the related dye-sensitized models. We show that quantum confinement in the ZnO nanostructures substantially affects the dye/semiconductor alignment of energy levels, with smaller ZnO models providing unfavourable electron injection. An increasing broadening of the dye LUMO is found moving to larger substrates, substantially contributing to the interfacial electronic coupling. TDDFT excited state calculations for the investigated dye@(ZnO)(222) system are fully consistent with experimental data, quantitatively reproducing the red-shift and broadening of the visible absorption spectrum observed for the ZnO-anchored dye compared to the dye in solution. TDDFT calculations on the fully interacting system also introduce a contribution to the dye/semiconductor admixture, due to configurational excited state mixing. Our results highlight the importance of quantum confinement in dye-sensitized ZnO interfaces, and provide the fundamental insight lying at the heart of the associated DSC devices. PMID:22743544

  16. A way for studying the impact of PEDOT:PSS interface layer on carrier transport in PCDTBT:PC{sub 71}BM bulk hetero junction solar cells by electric field induced optical second harmonic generation measurement

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Zubair, E-mail: zubairtarar@um.edu.my; Abdullah, Shahino Mah; Sulaiman, Khaulah [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Taguchi, Dai; Iwamoto, Mitsumasa [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2015-04-28

    Electric-field-induced optical second-harmonic generation (EFISHG) measurement was employed to study the impact of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) interface layer on the carrier transport mechanism of the PCDTBT:PC{sub 71}BM bulk heterojunction (BHJ) organic solar cells (OSCs). We revealed that the electric fields in the PCDTBT and PC{sub 71}BM were allowed to be measured individually by choosing fundamental laser wavelengths of 1000 nm and 1060 nm, respectively, in dark and under illumination. The results showed that the direction of the internal electric fields in the PCDTBT:PC{sub 71}BM BHJ layer is reversed by introducing the PEDOT:PSS layer, and this results in longer electron transport time in the BHJ layer. We conclude that TR-EFISHG can be used as a novel way for studying the impact of interfacial layer on the transport of electrons and holes in the bulk-heterojunction OSCs.

  17. Photovoltaic performance improvement of dye-sensitized solar cells through introducing In-doped TiO2 film at conducting glass and mesoporous TiO2 interface as an efficient compact layer

    International Nuclear Information System (INIS)

    In-doped TiO2 thin film was introduced at the interface of fluorine-doped tin oxide (FTO) substrate and mesoporous TiO2 film by spin-coating method, and its application as a new compact layer material for dye-sensitized solar cells (DSSCs) was investigated. The scanning electron microscopy (SEM), UV-visible spectroscopy, current-voltage characteristics, Mott-Schottky analysis, electrochemical impedance spectroscopy (EIS) analysis and open-circuit voltage decay (OCVD) technique are used to characterize the morphology, optical transmittance and flat-band potentials (Vfb) of In-doped titania compact film and its effect to the photoelectron conversion process. It was found that In-doping increased the transmittance of TiO2 compact layer, the interfacial resistance between FTO substrate and porous TiO2 film and the flat-band potential of TiO2 film. The In-doped TiO2 compact layer effectively suppressed the charge recombination from FTO to the electrolyte, increased the optical absorption of dye and then increased the short-circuit photocurrent density (Jsc). Furthermore, In-doped TiO2 compact layer acted as a weak energy barrier, which increased the electron density in the mesoporous TiO2 film, thus improved open-circuit photovoltage (Voc). As a result, the overall energy conversion efficiency of the DSSC with In-doped TiO2 compact layer was enhanced by 11.9% and 6.9% compared to the DSSC without compact layer and with pure TiO2 compact layer, respectively. It indicated that In-doped TiO2 is a promising compact layer material for dye-sensitized solar cells

  18. REAL- ESTATE INTERFACE

    OpenAIRE

    Jawad, Mohamad

    2016-01-01

    The purpose of the thesis was to implement the most efficient user interface (UI) for Real-estate in Finland for client companies due to their desire of having this feature in their system. The prototype was supposed to show the clients how the feature works to get needed data for real-estate properties in Finland in their map system. National Land Survey MML of Finland was chosen for tracking the real-estate properties data in the system. The real-estate prototype was developed by Micros...

  19. User interface concerns

    Science.gov (United States)

    Redhed, D. D.

    1978-01-01

    Three possible goals for the Numerical Aerodynamic Simulation Facility (NASF) are: (1) a computational fluid dynamics (as opposed to aerodynamics) algorithm development tool; (2) a specialized research laboratory facility for nearly intractable aerodynamics problems that industry encounters; and (3) a facility for industry to use in its normal aerodynamics design work that requires high computing rates. The central system issue for industry use of such a computer is the quality of the user interface as implemented in some kind of a front end to the vector processor.

  20. Sistema Brain Computer Interface

    OpenAIRE

    Martín Barraza, Juan Ignacio

    2015-01-01

    En este trabajo de final de grado se realizará una aplicación de un sistema Brain Computer Interface en el cual, a partir del dipositivo Mind Wave de la compañía Neurosky, se pretenderá controlar el prototipo de una mano humana. Esta será controlada a partir de las ondas cerebrales medidas por el sensor que el dispositivo dispone. A continuación, la información captada por nuestro medidor de señales de electroencefalográficas será enviada por radiofrecuencia a un stick USB que viene incorpora...

  1. Urban Sound Interfaces

    DEFF Research Database (Denmark)

    Breinbjerg, Morten

    2012-01-01

    This paper draws on the theories of Michel de Certeau and Gaston Bachelard to discuss how media architecture, in the form of urban sound interfaces, can help us perceive the complexity of the spaces we inhabit, by exploring the history and the narratives of the places in which we live. In this...... paper, three sound works are discussed in relation to the iPod, which is considered as a more private way to explore urban environments, and as a way to control the individual perception of urban spaces....

  2. MAN – MACHINE INTERFACE

    Directory of Open Access Journals (Sweden)

    S.Bhuvaneswari

    2012-02-01

    Full Text Available Agents trained by learning techniques provide a powerful approximation of state spaces in games that aretoo large for naive approaches. In the study Genetic Algorithms and Manual Interface was implementedand used to train agents for the board game LUDO. The state space of LUDO is generalized to a small setand encoded to suit the different techniques. The impact of variables and tactics applied in training aredetermined. Agents based on the techniques performed satisfactory against a baseline finite agent, and aGenetic Algorithm based agent performed satisfactory against competitors from the course. Better statespace representations will improve the success of learning based agents.

  3. Interfacing with the Night

    OpenAIRE

    McLean, Alex; Parkinson, Adam

    2014-01-01

    In  this  paper,  the  authors  consider  the  interfaces  between academia and dance music. Dance music and club culture are, we argue, important to computer music and the live performance of electronic music, but there are many different difficulties encountered when trying to present electronic dance music within academic contexts. The authors draw upon their experiences as promoters, performers, researchers and audience members to discuss these difficulties and how and why we might negoti...

  4. Man - Machine Interface

    Directory of Open Access Journals (Sweden)

    S.Bhuvaneswari

    2012-01-01

    Full Text Available Agents trained by learning techniques provide a powerful approximation of state spaces in games that are too large for naive approaches. In the study Genetic Algorithms and Manual Interface was implemented and used to train agents for the board game LUDO. The state space of LUDO is generalized to a small set and encoded to suit the different techniques. The impact of variables and tactics applied in training are determined. Agents based on the techniques performed satisfactory against a baseline finite agent, and a Genetic Algorithm based agent performed satisfactory against competitors from the course. Better state space representations will improve the success of learning based agents.

  5. Bubble and drop interfaces

    CERN Document Server

    Miller

    2011-01-01

    The book aims at describing the most important experimental methods for characterizing liquid interfaces, such as drop profile analysis, bubble pressure and drop volume tensiometry, capillary pressure technique, and oscillating drops and bubbles. Besides the details of experimental set ups, also the underlying theoretical basis is presented in detail. In addition, a number of applications based on drops and bubbles is discussed, such as rising bubbles and the very complex process of flotation. Also wetting, characterized by the dynamics of advancing contact angles is discussed critically. Spec

  6. Modelling biological invasions: Individual to population scales at interfaces

    KAUST Repository

    Belmonte-Beitia, J.

    2013-10-01

    Extracting the population level behaviour of biological systems from that of the individual is critical in understanding dynamics across multiple scales and thus has been the subject of numerous investigations. Here, the influence of spatial heterogeneity in such contexts is explored for interfaces with a separation of the length scales characterising the individual and the interface, a situation that can arise in applications involving cellular modelling. As an illustrative example, we consider cell movement between white and grey matter in the brain which may be relevant in considering the invasive dynamics of glioma. We show that while one can safely neglect intrinsic noise, at least when considering glioma cell invasion, profound differences in population behaviours emerge in the presence of interfaces with only subtle alterations in the dynamics at the individual level. Transport driven by local cell sensing generates predictions of cell accumulations along interfaces where cell motility changes. This behaviour is not predicted with the commonly used Fickian diffusion transport model, but can be extracted from preliminary observations of specific cell lines in recent, novel, cryo-imaging. Consequently, these findings suggest a need to consider the impact of individual behaviour, spatial heterogeneity and especially interfaces in experimental and modelling frameworks of cellular dynamics, for instance in the characterisation of glioma cell motility. © 2013 Elsevier Ltd.

  7. Laparoscopic simulation interface

    Science.gov (United States)

    Rosenberg, Louis B.

    2006-04-04

    A method and apparatus for providing high bandwidth and low noise mechanical input and output for computer systems. A gimbal mechanism provides two revolute degrees of freedom to an object about two axes of rotation. A linear axis member is coupled to the gimbal mechanism at the intersection of the two axes of rotation. The linear axis member is capable of being translated along a third axis to provide a third degree of freedom. The user object is coupled to the linear axis member and is thus translatable along the third axis so that the object can be moved along all three degrees of freedom. Transducers associated with the provided degrees of freedom include sensors and actuators and provide an electromechanical interface between the object and a digital processing system. Capstan drive mechanisms transmit forces between the transducers and the object. The linear axis member can also be rotated about its lengthwise axis to provide a fourth degree of freedom, and, optionally, a floating gimbal mechanism is coupled to the linear axis member to provide fifth and sixth degrees of freedom to an object. Transducer sensors are associated with the fourth, fifth, and sixth degrees of freedom. The interface is well suited for simulations of medical procedures and simulations in which an object such as a stylus or a joystick is moved and manipulated by the user.

  8. Portraying User Interface History

    DEFF Research Database (Denmark)

    Jørgensen, Anker Helms

    The user interface is coming of age. Papers adressing UI history have appeared in fair amounts in the last 25 years. Most of them address particular aspects such as an in­novative interface paradigm or the contribution of a visionary or a research lab. Contrasting this, papers addres­sing UI...... history. Next the paper analyses a selected sample of papers on UI history at large. The analysis shows that the current state-of-art is featured by three aspects: Firstly internalism, in that the papers adress the tech­nologies in their own right with little con­text­ualization, secondly whiggism in that...... they largely address prevailing UI techno­logies, and thirdly history from above in that they focus on the great deeds of the visionaries. The paper then compares this state-of-art in UI history to the much more mature fields history of computing and history of technology. Based hereon, some...

  9. Nanomechanics based investigation into interface -thermomechanics of collagen and chitin based biomaterials

    OpenAIRE

    Qu, Tao; Tomar, Vikas

    2014-01-01

    From the biological/chemical perspective, interface concepts related to cell surface/synthetic biomaterial interface and extracellular matrix/biomolecule interface have wide applications in medical and biological technology. Some findings regarding interfaces controlling biological reactions are like surfaces provide high accessibility for reaction, high surface area geometries that can be created to enhance reaction turnover rates, unique organic microenvironments that can enhance specific a...

  10. Distinctive glial and neuronal interfacing on nanocrystalline diamond.

    Directory of Open Access Journals (Sweden)

    Amel Bendali

    Full Text Available Direct electrode/neuron interfacing is a key challenge to achieve high resolution of neuronal stimulation required for visual prostheses. Neuronal interfacing on biomaterials commonly requires the presence of glial cells and/or protein coating. Nanocrystalline diamond is a highly mechanically stable biomaterial with a remarkably large potential window for the electrical stimulation of tissues. Using adult retinal cell cultures from rats, we found that glial cells and retinal neurons grew equally well on glass and nanocrystalline diamond. The use of a protein coating increased cell survival, particularly for glial cells. However, bipolar neurons appeared to grow even in direct contact with bare diamond. We investigated whether the presence of glial cells contributed to this direct neuron/diamond interface, by using purified adult retinal ganglion cells to seed diamond and glass surfaces with and without protein coatings. Surprisingly, these fully differentiated spiking neurons survived better on nanocrystalline diamond without any protein coating. This greater survival was indicated by larger cell numbers and the presence of longer neurites. When a protein pattern was drawn on diamond, neurons did not grow preferentially on the coated area, by contrast to their behavior on a patterned glass. This study highlights the interesting biocompatibility properties of nanocrystalline diamond, allowing direct neuronal interfacing, whereas a protein coating was required for glial cell growth.

  11. Effect of a-Si:H interface buffer layer on the performance of hydrogenated amorphous silicon germanium thin film solar cell%非晶硅界面缓冲层对非晶硅锗电池性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘伯飞; 白立沙; 张德坤; 魏长春; 孙建; 侯国付; 赵颖; 张晓丹

    2013-01-01

    In the light of the open circuit voltage and fill factor reduction resulting from band gap discontinuities and high defect densities at interfaces when more germanium is mixed into the intrinsic layer of hydrogenated amorphous silicon germanium solar cell, the insertion of a-Si:H buffer layer with proper band gap into PI interface not only mitigates band gap discontinuities and interface recombination, but also improves the electric field distribution by reducing the defect densities at PI interface, thus the collection efficiency of a-SiGe:H solar cell is enhanced. By inserting a-Si:H buffer layer into IN interface and designing band gap profile along the a-SiGe:H intrinsic layer further, the 8.72%conversion efficiency of single junction a-SiGe:H solar cell is achieved when only Al back reflector is added as back contact.%针对非晶硅锗电池本征层高锗含量时界面带隙失配以及高界面缺陷密度造成电池开路电压和填充因子下降的问题,通过在PI界面插入具有合适带隙的非晶硅缓冲层,不仅有效缓和了带隙失配,降低界面复合,同时也通过降低界面缺陷密度改善内建电场分布,从而提高了电池的收集效率.进一步引入IN界面缓冲层以及对非晶硅锗本征层进行能带梯度设计,在仅采用Al背电极时,单结非晶硅锗电池转换效率达8.72%.

  12. Charge Transfer Excitons at van der Waals Interfaces.

    Science.gov (United States)

    Zhu, Xiaoyang; Monahan, Nicholas R; Gong, Zizhou; Zhu, Haiming; Williams, Kristopher W; Nelson, Cory A

    2015-07-01

    The van der Waals interfaces of molecular donor/acceptor or graphene-like two-dimensional (2D) semiconductors are central to concepts and emerging technologies of light-electricity interconversion. Examples include, among others, solar cells, photodetectors, and light emitting diodes. A salient feature in both types of van der Waals interfaces is the poorly screened Coulomb potential that can give rise to bound electron-hole pairs across the interface, i.e., charge transfer (CT) or interlayer excitons. Here we address common features of CT excitons at both types of interfaces. We emphasize the competition between localization and delocalization in ensuring efficient charge separation. At the molecular donor/acceptor interface, electronic delocalization in real space can dictate charge carrier separation. In contrast, at the 2D semiconductor heterojunction, delocalization in momentum space due to strong exciton binding may assist in parallel momentum conservation in CT exciton formation. PMID:26001297

  13. Switchable bioelectronics on graphene interface (Presentation Recording)

    Science.gov (United States)

    Parlak, Onur; Tiwari, Ashutosh; Turner, Anthony P. F.

    2015-08-01

    Smart and flexible bioelectronics on graphene have emerged as a new frontier in the field of biosensors and bioelectronics. Graphene has begun to be seen as an ideal signal transducer and a promising alternative for the production of low-cost bioelectronic devices.1-2 However, biological systems used in these devices suffer from a lack of control and regulation. There is an obvious need to develop "switchable" and "smart" interfaces for both fundamental and applied studies. Here, we report the fabrication of a stimuli-responsive graphene interface, which is used to regulate biomolecular reactions. The present study aims to address the design and development of a novel auto-switchable graphene bio-interface that is capable of positively responding, by creating smart nanoarchitectures. By changing the external conditions such as temperature, light and pH of the medium, we acheived control of the biochemical interactions. In the negative mode, access of an associated enzyme to its substrate is largely restricted, resulting in a decrease in the diffusion of reactants and the consequent activity of the system. In contrast, the biosubstrate could freely access the enzyme facilitating bioelectrocatalysis in a positive response. Using electrochemical techniques, we demonstrated that interfacial bio-electrochemical properties can be tuned by modest changes in conditions. Such an ability to independently regulate the behaviour of the interface has important implications for the design of novel bioreactors, biofuel cells and biosensors with inbuilt self-control features.

  14. Size-dependent protein segregation at membrane interfaces

    Science.gov (United States)

    Schmid, Eva M.; Bakalar, Matthew H.; Choudhuri, Kaushik; Weichsel, Julian; Ann, Hyoung Sook; Geissler, Phillip L.; Dustin, Michael L.; Fletcher, Daniel A.

    2016-07-01

    Membrane interfaces formed at cell-cell junctions are associated with characteristic patterns of membrane proteins whose organization is critical for intracellular signalling. To isolate the role of membrane protein size in pattern formation, we reconstituted model membrane interfaces in vitro using giant unilamellar vesicles decorated with synthetic binding and non-binding proteins. We show that size differences between membrane proteins can drastically alter their organization at membrane interfaces, with as little as a ~5 nm increase in non-binding protein size driving its exclusion from the interface. Combining in vitro measurements with Monte Carlo simulations, we find that non-binding protein exclusion is also influenced by lateral crowding, binding protein affinity, and thermally driven membrane height fluctuations that transiently limit access to the interface. This sensitive and highly effective means of physically segregating proteins has implications for cell-cell contacts such as T-cell immunological synapses (for example, CD45 exclusion) and epithelial cell junctions (for example, E-cadherin enrichment), as well as for protein sorting at intracellular contact points between membrane-bound organelles.

  15. Local Electronic And Dielectric Properties at Nanosized Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bonnell, Dawn A. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2015-02-23

    Final Report to the Department of Energy for period 6/1/2000 to 11/30/2014 for Grant # DE-FG02-00ER45813-A000 to the University of Pennsylvania Local Electronic And Dielectric Properties at Nanosized Interfaces PI: Dawn Bonnell The behavior of grain boundaries and interfaces has been a focus of fundamental research for decades because variations of structure and composition at interfaces dictate mechanical, electrical, optical and dielectric properties in solids. Similarly, the consequence of atomic and electronic structures of surfaces to chemical and physical interactions are critical due to their implications to catalysis and device fabrication. Increasing fundamental understanding of surfaces and interfaces has materially advanced technologies that directly bear on energy considerations. Currently, exciting developments in materials processing are enabling creative new electrical, optical and chemical device configurations. Controlled synthesis of nanoparticles, semiconducting nanowires and nanorods, optical quantum dots, etc. along with a range of strategies for assembling and patterning nanostructures portend the viability of new devices that have the potential to significantly impact the energy landscape. As devices become smaller the impact of interfaces and surfaces grows geometrically. As with other nanoscale phenomena, small interfaces do not exhibit the same properties as do large interfaces. The size dependence of interface properties had not been explored and understanding at the most fundamental level is necessary to the advancement of nanostructured devices. An equally important factor in the behavior of interfaces in devices is the ability to examine the interfaces under realistic conditions. For example, interfaces and boundaries dictate the behavior of oxide fuel cells which operate at extremely high temperatures in dynamic high pressure chemical environments. These conditions preclude the characterization of local properties during fuel cell

  16. Human-computer interface

    Science.gov (United States)

    Anderson, Thomas G.

    2004-12-21

    The present invention provides a method of human-computer interfacing. Force feedback allows intuitive navigation and control near a boundary between regions in a computer-represented space. For example, the method allows a user to interact with a virtual craft, then push through the windshield of the craft to interact with the virtual world surrounding the craft. As another example, the method allows a user to feel transitions between different control domains of a computer representation of a space. The method can provide for force feedback that increases as a user's locus of interaction moves near a boundary, then perceptibly changes (e.g., abruptly drops or changes direction) when the boundary is traversed.

  17. Space as interface

    DEFF Research Database (Denmark)

    Lykke-Olesen, Andreas

    2006-01-01

    This Ph.D. dissertation takes its offset in the migration of technology and computing power into our physical environment. The consequence of this movement, termed ubiquitous computing (Wieser, 1991), is a new relationship between humans, technology and spaces. In this new context, I seek...... to conceptualize space as more than the physical container for human activity. I do this by investigating space as interface. Based on a theory of space and place set forth by Tuan (Tuan, 1977), and informed by an explorative research approach, I make the distinction between space and place as a Euclidian space...... and a Phenomenological experienced place. In this perspective, place is created by humans as they appropriate space in investing it with emotions and memories and hereby making it meaningful. Space consists of formable physical and digital space, whereas place is made up by four dimensions relating to personal, physical...

  18. Oscars and Interfaces

    Directory of Open Access Journals (Sweden)

    Antony Unwin

    2012-06-01

    Full Text Available Graphical user interfaces (GUIs are gradually becoming more powerful and more accepted. They are the standard way of interacting with the web and play an increasing role in many software applications. Nevertheless, they have not been generally adopted, and critics point to particular weaknesses and disadvantages. Many of these are due more to flaws in design and implementation than to the basic concepts of GUIs. More attention could be paid to what users want to do and how a GUI might be developed to support these goals. Using a dataset about Oscar nominees and winners, this paper considers what analyses statisticians might carry out and what kind of GUI would be appropriate for these tasks. (It also offers some insights into the Oscars dataset.

  19. Nuclear data interface retrospective

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Mark G [Los Alamos National Laboratory

    2008-01-01

    The Nuclear Data Interface (NDI) code library and data formats are the standards for multigroup nuclear data at Los Alamos National Laboratory. NDI's analysis, design, implementation, testing, integration, and maintenance required a ten person-year and ongoing effort by the Nuclear Data Team. Their efforts provide a unique, contemporary experience in producing a standard component library. In reflection upon that experience at NDI's decennial, we have identified several factors critical to NDI's success: it addressed real problems with appropriate simplicity, it fully supported all users, it added extra value through the code to the raw nuclear data, and its team went the distance from analysis through maintenance. In this report we review these critical success factors and discuss their implications for future standardization projects.

  20. Ions at hydrophobic interfaces

    International Nuclear Information System (INIS)

    We review the present understanding of the behavior of ions at the air–water and oil–water interfaces. We argue that while the alkali metal cations remain strongly hydrated and are repelled from the hydrophobic surfaces, the anions must be classified into kosmotropes and chaotropes. The kosmotropes remain strongly hydrated in the vicinity of a hydrophobic surface, while the chaotropes lose their hydration shell and can become adsorbed to the interface. The mechanism of adsorption is still a subject of debate. Here, we argue that there are two driving forces for anionic adsorption: the hydrophobic cavitational energy and the interfacial electrostatic surface potential of water. While the cavitational contribution to ionic adsorption is now well accepted, the role of the electrostatic surface potential is much less clear. The difficulty is that even the sign of this potential is a subject of debate, with the ab initio and the classical force field simulations predicting electrostatic surface potentials of opposite sign. In this paper, we will argue that the strong anionic adsorption found in the polarizable force field simulations is the result of the artificial electrostatic surface potential present in the classical water models. We will show that if the adsorption of anions were as large as predicted by the polarizable force field simulations, the excess surface tension of the NaI solution would be strongly negative, contrary to the experimental measurements. While the large polarizability of heavy halides is a fundamental property and must be included in realistic modeling of the electrolyte solutions, we argue that the point charge water models, studied so far, are incompatible with the polarizable ionic force fields when the translational symmetry is broken. The goal for the future should be the development of water models with very low electrostatic surface potential. We believe that such water models will be compatible with the polarizable force fields