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Sample records for air-liquid interface cell

  1. Exposure of Mammalian Cells to Air-Pollutant Mixtures at the Air-Liquid Interface

    Science.gov (United States)

    It has been widely accepted that exposure of mammalian cells to air-pollutant mixtures at the air-liquid interface is a more realistic approach than exposing cell under submerged conditions. The VITROCELL systems, are commercially available systems for air-liquid interface expo...

  2. 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.

  3. Growth of human bronchial epithelial cells at an air-liquid interface alters the response to particle exposure

    Science.gov (United States)

    Abstract: We tested the hypothesis that relative to submerged cells, airway epithelial cells grown at an air-liquid interface would have an altered response to particle exposure. RNA for IL-8, IL-6, heme oxygenase 1 and cyclooxygenase 2 increased following exposure of submer...

  4. Culturing of Human Nasal Epithelial Cells at the Air Liquid Interface

    Science.gov (United States)

    Müller, Loretta; Brighton, Luisa E.; Carson, Johnny L.; Fischer, William A.; Jaspers, Ilona

    2013-01-01

    In vitro models using human primary epithelial cells are essential in understanding key functions of the respiratory epithelium in the context of microbial infections or inhaled agents. Direct comparisons of cells obtained from diseased populations allow us to characterize different phenotypes and dissect the underlying mechanisms mediating changes in epithelial cell function. Culturing epithelial cells from the human tracheobronchial region has been well documented, but is limited by the availability of human lung tissue or invasiveness associated with obtaining the bronchial brushes biopsies. Nasal epithelial cells are obtained through much less invasive superficial nasal scrape biopsies and subjects can be biopsied multiple times with no significant side effects. Additionally, the nose is the entry point to the respiratory system and therefore one of the first sites to be exposed to any kind of air-borne stressor, such as microbial agents, pollutants, or allergens. Briefly, nasal epithelial cells obtained from human volunteers are expanded on coated tissue culture plates, and then transferred onto cell culture inserts. Upon reaching confluency, cells continue to be cultured at the air-liquid interface (ALI), for several weeks, which creates more physiologically relevant conditions. The ALI culture condition uses defined media leading to a differentiated epithelium that exhibits morphological and functional characteristics similar to the human nasal epithelium, with both ciliated and mucus producing cells. Tissue culture inserts with differentiated nasal epithelial cells can be manipulated in a variety of ways depending on the research questions (treatment with pharmacological agents, transduction with lentiviral vectors, exposure to gases, or infection with microbial agents) and analyzed for numerous different endpoints ranging from cellular and molecular pathways, functional changes, morphology, etc. In vitro models of differentiated human nasal epithelial

  5. Culturing of human nasal epithelial cells at the air liquid interface.

    Science.gov (United States)

    Müller, Loretta; Brighton, Luisa E; Carson, Johnny L; Fischer, William A; Jaspers, Ilona

    2013-10-08

    In vitro models using human primary epithelial cells are essential in understanding key functions of the respiratory epithelium in the context of microbial infections or inhaled agents. Direct comparisons of cells obtained from diseased populations allow us to characterize different phenotypes and dissect the underlying mechanisms mediating changes in epithelial cell function. Culturing epithelial cells from the human tracheobronchial region has been well documented, but is limited by the availability of human lung tissue or invasiveness associated with obtaining the bronchial brushes biopsies. Nasal epithelial cells are obtained through much less invasive superficial nasal scrape biopsies and subjects can be biopsied multiple times with no significant side effects. Additionally, the nose is the entry point to the respiratory system and therefore one of the first sites to be exposed to any kind of air-borne stressor, such as microbial agents, pollutants, or allergens. Briefly, nasal epithelial cells obtained from human volunteers are expanded on coated tissue culture plates, and then transferred onto cell culture inserts. Upon reaching confluency, cells continue to be cultured at the air-liquid interface (ALI), for several weeks, which creates more physiologically relevant conditions. The ALI culture condition uses defined media leading to a differentiated epithelium that exhibits morphological and functional characteristics similar to the human nasal epithelium, with both ciliated and mucus producing cells. Tissue culture inserts with differentiated nasal epithelial cells can be manipulated in a variety of ways depending on the research questions (treatment with pharmacological agents, transduction with lentiviral vectors, exposure to gases, or infection with microbial agents) and analyzed for numerous different endpoints ranging from cellular and molecular pathways, functional changes, morphology, etc. In vitro models of differentiated human nasal epithelial

  6. Growth of airway epithelial cells at an air-liquid interface changes both the response to particle exposure and iron homeostasis

    Science.gov (United States)

    We tested the hypothesis that 1) relative to submerged cells, airway epithelial cells grown at an air-liquid interface and allowed to differentiate would have an altered response to particle exposure and 2) that these differences would be associated with indices of iron homeostas...

  7. 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

    2016-08-30

    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.

  8. Aerosol generation and characterization of multi-walled carbon nanotubes exposed to cells cultured at the air-liquid interface.

    Science.gov (United States)

    Polk, William W; Sharma, Monita; Sayes, Christie M; Hotchkiss, Jon A; Clippinger, Amy J

    2016-04-23

    Aerosol generation and characterization are critical components in the assessment of the inhalation hazards of engineered nanomaterials (NMs). An extensive review was conducted on aerosol generation and exposure apparatus as part of an international expert workshop convened to discuss the design of an in vitro testing strategy to assess pulmonary toxicity following exposure to aerosolized particles. More specifically, this workshop focused on the design of an in vitro method to predict the development of pulmonary fibrosis in humans following exposure to multi-walled carbon nanotubes (MWCNTs). Aerosol generators, for dry or liquid particle suspension aerosolization, and exposure chambers, including both commercially available systems and those developed by independent researchers, were evaluated. Additionally, characterization methods that can be used and the time points at which characterization can be conducted in order to interpret in vitro exposure results were assessed. Summarized below is the information presented and discussed regarding the relevance of various aerosol generation and characterization techniques specific to aerosolized MWCNTs exposed to cells cultured at the air-liquid interface (ALI). The generation of MWCNT aerosols relevant to human exposures and their characterization throughout exposure in an ALI system is critical for extrapolation of in vitro results to toxicological outcomes in humans.

  9. Hydrodynamical entrapment of ciliates at the air-liquid interface

    Science.gov (United States)

    Ferracci, Jonathan; Ueno, Hironori; Numayama-Tsuruta, Keiko; Imai, Yohsuke; Yamaguchi, Takami; Ishikawa, Takuji

    2012-11-01

    We found the new phenomenon of the entrapment of ciliates at the air-water interface, though they are not trapped by a solid interface. We first characterize the behaviours of cells at the interface by comparing it to those away from interfaces. The results showed that the cell's swimming velocity is considerably reduced at the air-water interface. In order to experimentally verify the possible physiological causes of the entrapment, we observed their behaviours in absence of positive chemotaxis for oxygen and the negative geotaxis. The results illustrated that the entrapment phenomenon was not dependent on these physiological conditions. The experiments using surfactant revealed that the entrapment phenomenon was strongly affected by the velocity-stress conditions at the interface. This fact was confirmed numerically by a boundary element method, i.e. the stress-free condition at the air-liquid interface is one of the main mechanisms of the entrapment phenomenon found in the experiments. Since the entrapment phenomenon found in this study affects the cell-cell interactions and the mass transport at the interface, the knowledge obtained in this study is useful for better understanding the complex behaviours of swimming microorganisms in nature. PhD student in the Physiological Flow Studies Laboratory.

  10. A new computer-controlled air-liquid interface cultivation system for the generation of differentiated cell cultures of the airway epithelium.

    Science.gov (United States)

    Aufderheide, Michaela; Förster, Christine; Beschay, Morris; Branscheid, Detlev; Emura, Makito

    2016-01-01

    The increased application of in vitro systems in pharmacology and toxicology requires cell culture systems that facilitate the cultivation process and ensure stable, reproducible and controllable cultivation conditions. Up to now, some devices have been developed for the cultivation of cells under submersed conditions. However, systems meeting the requirements of an air-liquid interface (ALI) cultivation for the special needs of bronchial epithelial cells for example are still lacking. In order to obtain in vivo like organization and differentiation of these cells they need to be cultivated under ALI conditions on microporous membranes in direct contact with the environmental atmosphere. For this purpose, a Long-Term-Cultivation system was developed (CULTEX(®) LTC-C system) for the computer-controlled cultivation of such cells. The transwell inserts are placed in an incubator module (24 inserts), which can be adjusted for the medium level (ultrasonic pulse-echosensor), time and volume-dependent medium exchange, and frequency for mixing the medium with a rotating disc for homogeneous distribution of medium and secretion components. Normal primary freshly isolated bronchial epithelial cells were cultivated for up to 38 days to show the efficiency of such a cultivation procedure for generating 3D cultures exhibiting in vivo-like pseudostratified organization of the cells as well as differentiation characteristics like mucus-producing and cilia-forming cells.

  11. Toxicity of copper oxide nanoparticles in lung epithelial cells exposed at the air-liquid interface compared with in vivo assessment.

    Science.gov (United States)

    Jing, Xuefang; Park, Jae Hong; Peters, Thomas M; Thorne, Peter S

    2015-04-01

    The toxicity of spark-generated copper oxide nanoparticles (CuONPs) was evaluated in human bronchial epithelial cells (HBEC) and lung adenocarcinoma cells (A549 cells) using an in vitro air-liquid interface (ALI) exposure system. Dose-response results were compared to in vivo inhalation and instillation studies of CuONPs. Cells were exposed to filtered, particle-free clean air (controls) or spark-generated CuONPs. The number median diameter, geometric standard deviation and total number concentration of CuONPs were 9.2 nm, 1.48 and 2.27×10(7)particles/cm(3), respectively. Outcome measures included cell viability, cytotoxicity, oxidative stress and proinflammatory chemokine production. Exposure to clean air (2 or 4h) did not induce toxicity in HBEC or A549 cells. Compared with controls, CuONP exposures significantly reduced cell viability, increased lactate dehydrogenase (LDH) release and elevated levels of reactive oxygen species (ROS) and IL-8 in a dose-dependent manner. A549 cells were significantly more susceptible to CuONP effects than HBEC. Antioxidant treatment reduced CuONP-induced cytotoxicity. When dose was expressed per area of exposed epithelium there was good agreement of toxicity measures with murine in vivo studies. This demonstrates that in vitro ALI studies can provide meaningful data on nanotoxicity of metal oxides.

  12. Evaluation of air-liquid interface exposure systems for in vitro assessment of airborne pollutants

    Science.gov (United States)

    Exposure of cells to airborne pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of submerged cells. The published literature, however, describes irreproducible and/or unrealistic experimental conditions using ALI systems. We have compared fi...

  13. Critical Evaluation of Air-Liquid Interface Exposure Devices for In Vitro Assessment of Atmospheric Pollutants

    Science.gov (United States)

    Exposure of cells to atmospheric pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of attached cells submerged in liquid medium. However, there is still limited understanding of the ideal ALI device design features that permit reproducible a...

  14. Culture of primary ciliary dyskinesia epithelial cells at air-liquid interface can alter ciliary phenotype but remains a robust and informative diagnostic aid.

    Directory of Open Access Journals (Sweden)

    Robert A Hirst

    Full Text Available BACKGROUND: The diagnosis of primary ciliary dyskinesia (PCD requires the analysis of ciliary function and ultrastructure. Diagnosis can be complicated by secondary effects on cilia such as damage during sampling, local inflammation or recent infection. To differentiate primary from secondary abnormalities, re-analysis of cilia following culture and re-differentiation of epithelial cells at an air-liquid interface (ALI aids the diagnosis of PCD. However changes in ciliary beat pattern of cilia following epithelial cell culture has previously been described, which has brought the robustness of this method into question. This is the first systematic study to evaluate ALI culture as an aid to diagnosis of PCD in the light of these concerns. METHODS: We retrospectively studied changes associated with ALI-culture in 158 subjects referred for diagnostic testing at two PCD centres. Ciliated nasal epithelium (PCD n = 54; non-PCD n  111 was analysed by high-speed digital video microscopy and transmission electron microscopy before and after culture. RESULTS: Ciliary function was abnormal before and after culture in all subjects with PCD; 21 PCD subjects had a combination of static and uncoordinated twitching cilia, which became completely static following culture, a further 9 demonstrated a decreased ciliary beat frequency after culture. In subjects without PCD, secondary ciliary dyskinesia was reduced. CONCLUSIONS: The change to ciliary phenotype in PCD samples following cell culture does not affect the diagnosis, and in certain cases can assist the ability to identify PCD cilia.

  15. Use of a feline respiratory epithelial cell culture system grown at the air-liquid interface to characterize the innate immune response following feline herpesvirus 1 infection.

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    Nelli, Rahul K; Maes, Roger; Kiupel, Matti; Hussey, Gisela Soboll

    2016-03-02

    Infection with feline herpesvirus-1 (FHV-1) accounts for 50% of viral upper respiratory diseases in domestic cats and is a significant cause of ocular diseases. Despite the clinical significance and high prevalence of FHV-1 infection, currently available vaccines cannot completely protect cats from infection and lifelong latency. FHV-1 infects via the mucous membranes and replicates in respiratory epithelial cells, but very little is known about the early innate immunity at this site. To address questions about immunity to FHV-1, feline respiratory epithelial cells cultured at air-liquid interface (ALI-FRECs) were established by collecting respiratory tracts from 6 healthy cats after euthanasia. Cells were isolated, cultured and characterized histologically and immunologically before infection with FHV-1. The expression of Toll-like receptors (TLRs), cytokine and chemokine responses were measured by real time PCR. ALI-FRECs morphologically resembled the natural airways of cats with multilayered columnar epithelial cells and cilia. Immunological properties of the natural airways were maintained in ALI-FRECs, as evidenced by the expression of TLRs, cytokines, chemokines, interferons, beta-defensins, and other regulatory genes. Furthermore, ALI-FRECs were able to support infection and replication of FHV-1, as well as modulate transcriptional regulation of various immune genes in response to infection. IL-1β and TNFα were increased in ALI-FRECs by 24hpi, whereas expression levels of IFN-α and TLR9 were not increased until 36hpi. In contrast, TLR3, GM-CSF and TGF-1β expression was down-regulated at 36hpi. The data presented show the development of a system ideal for investigating the molecular pathogenesis and immunity of FHV-1 or other respiratory pathogens.

  16. Critical Evaluation of Air-Liquid Interface Cell Exposure Systems for in Vitro Assessment of Atmospheric Pollutants

    Science.gov (United States)

    We compared various in vitro exposure systems for their ability to expose cells to particles and gases. The systems tested use different mechanisms to deliver multi-pollutants to the cells: diffusion, sedimentation, thermophoresis (THP) and electrostatic precipitation (ESP). Vari...

  17. A novel method for pulmonary research: assessment of bioenergetic function at the air-liquid interface.

    Science.gov (United States)

    Xu, Weiling; Janocha, Allison J; Leahy, Rachel A; Klatte, Ryan; Dudzinski, Dave; Mavrakis, Lori A; Comhair, Suzy A A; Lauer, Mark E; Cotton, Calvin U; Erzurum, Serpil C

    2014-01-01

    Air-liquid interface cell culture is an organotypic model for study of differentiated functional airway epithelium in vitro. Dysregulation of cellular energy metabolism and mitochondrial function have been suggested to contribute to airway diseases. However, there is currently no established method to determine oxygen consumption and glycolysis in airway epithelium in air-liquid interface. In order to study metabolism in differentiated airway epithelial cells, we engineered an insert for the Seahorse XF24 Analyzer that enabled the measure of respiration by oxygen consumption rate (OCR) and glycolysis by extracellular acidification rate (ECAR). Oxidative metabolism and glycolysis in airway epithelial cells cultured on the inserts were successfully measured. The inserts did not affect the measures of OCR or ECAR. Cells under media with apical and basolateral feeding had less oxidative metabolism as compared to cells on the inserts at air-interface with basolateral feeding. The design of inserts that can be used in the measure of bioenergetics in small numbers of cells in an organotypic state may be useful for evaluation of new drugs and metabolic mechanisms that underlie airway diseases.

  18. Phenotypic modification of human airway epithelial cells in air-liquid interface culture induced by exposure to the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK).

    Science.gov (United States)

    Carson, Johnny L; Brighton, Luisa E; Jaspers, Ilona

    2015-04-01

    The nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent tobacco-specific carcinogen. We used an air-liquid interface epithelial cell culture system to model changes associated with NNK exposure relative to pathologies documented in human tobacco-related illnesses. Although in vitro systems exhibit certain limitations, they often offer accentuation of subtle pathologies. While the distribution of cell types in control cultures typically favors the ciliated cell phenotype, NNK-exposed cultures transitioned to non-ciliated cell phenotypes as well as reflecting features consistent with squamous metaplasia. We conclude that NNK impacts normal growth and differentiation of human airway epithelium in a short interval of time in vitro.

  19. Alveolar epithelial cells (A549) exposed at the air-liquid interface to diesel exhaust: First study in TNO's powertrain test center

    NARCIS (Netherlands)

    Kooter, I.M.; Alblas, M.J.; Jedynska, A.D.; Steenhof, M.; Houtzager, M.M.G.; Ras, M.G. van

    2013-01-01

    Air–liquid interface (ALI) exposures enable in vitro testing ofmixtures of gases and particles such as diesel exhaust (DE). The main objective of this study was to investigate the feasibility of exposing human lung epithelial cells at the ALI to complete DE generated by a heavy-duty truck in the sta

  20. Particle separation by a moving air-liquid interface in a microchannel.

    Science.gov (United States)

    Wang, Fengkun; Chon, Chan Hee; Li, Dongqing

    2010-12-15

    Particle separation is an important topic in microfluidic field and has recently gained significant attention in sample preparations for biological and chemical studies. In this paper, a novel particle separation method was proposed. In this method, the particles were separated by the air-liquid interface in a microchannel. The motion of the air-liquid interface was controlled with a syringe pump. Depending on the air-liquid interface speed, the liquid film thickness and the viscous force on particles were changed and the particles were separated by sizes. We observed the separation of 1.01 μm particles from the larger particles when the air-liquid interface speed was less than 11 μm/s, and the separation of both 1.01 μm and 5.09 μm particles from the larger particles when the interface speed was between 11 μm/s and 120 μm/s. When the speed was higher than 120 μm/s, the drag force of the liquid flow generated by the advancing interface on particles was so strong that the flow removed all particles off from the bottom channel wall and there were no particles left behind the advancing interface.

  1. Repeated whole cigarette smoke exposure alters cell differentiation and augments secretion of inflammatory mediators in air-liquid interface three-dimensional co-culture model of human bronchial tissue.

    Science.gov (United States)

    Ishikawa, Shinkichi; Ito, Shigeaki

    2017-02-01

    In vitro models of human bronchial epithelium are useful for toxicological testing because of their resemblance to in vivo tissue. We constructed a model of human bronchial tissue which has a fibroblast layer embedded in a collagen matrix directly below a fully-differentiated epithelial cell layer. The model was applied to whole cigarette smoke (CS) exposure repeatedly from an air-liquid interface culture while bronchial epithelial cells were differentiating. The effects of CS exposure on differentiation were determined by histological and gene expression analyses on culture day 21. We found a decrease in ciliated cells and perturbation of goblet cell differentiation. We also analyzed the effects of CS exposure on the inflammatory response, and observed a significant increase in secretion of IL-8, GRO-α, IL-1β, and GM-CSF. Interestingly, secretion of these mediators was augmented with repetition of whole CS exposure. Our data demonstrate the usefulness of our bronchial tissue model for in vitro testing and the importance of exposure repetition in perturbing the differentiation and inflammation processes.

  2. A Method To Measure Protein Unfolding at an Air-Liquid Interface.

    Science.gov (United States)

    Leiske, Danielle L; Shieh, Ian C; Tse, Martha Lovato

    2016-10-04

    Proteins are surface-active molecules that have a propensity to adsorb to hydrophobic interfaces, such as the air-liquid interface. Surface flow can increase aggregation of adsorbed proteins, which may be an undesirable consequence depending on the application. As changes in protein conformation upon adsorption are thought to induce aggregation, the ability to measure the folded state of proteins at interfaces is of particular interest. However, few techniques currently exist to measure protein conformation at interfaces. Here we describe a technique capable of measuring the hydrophobicity, and therefore the conformation and folded state, of proteins at air-liquid interfaces by exploiting the environmentally sensitive fluorophore Nile red. Two monoclonal antibodies (mAbs) with high (mAb1) and low (mAb2) surface activity were used to highlight the technique. Both mAbs showed low background fluorescence of Nile red in the liquid subphase and at a glass-liquid interface. In contrast, at the air-liquid interface Nile red fluorescence for mAb1 increased immediately after protein adsorption, whereas the Nile red fluorescence of the mAb2 film evolved more slowly in time even though the adsorbed quantity of protein remained constant. The results demonstrate that hydrophobicity upon mAb adsorption to the air-liquid interface evolves in a time-dependent manner. Interfacial hydrophobicity may be indicative of protein conformation or folded state, where rapid unfolding of mAb1 upon adsorption would be consistent with increased protein aggregation compared to mAb2. The ability to measure protein hydrophobicity at interfaces using Nile red, combined with small sample requirements and minimal sample preparation, fills a gap in existing interfacial techniques.

  3. UV-Vis reflection spectroscopy under variable angle incidence at the air-liquid interface.

    Science.gov (United States)

    Roldán-Carmona, Cristina; Rubia-Payá, Carlos; Pérez-Morales, Marta; Martín-Romero, María T; Giner-Casares, Juan J; Camacho, Luis

    2014-03-07

    The UV-Vis reflection spectroscopy (UV-Vis-RS) in situ at the air-liquid interface provides information about tilt and aggregation of chromophores in Langmuir monolayers. This information is particularly important given in most cases the chromophore is located at the polar region of the Langmuir monolayer. This region of the Langmuir monolayers has been hardly accessible by other experimental techniques. In spite of its enormous potential, the application of UV-Vis-RS has been limited mainly to reflection measurements under light normal incidence or at lower incidence angles than the Brewster angle. Remarkably, this technique is quite sensitive to the tilt of the chromophores at values of incidence angles close to or larger than the Brewster angle. Therefore, a novel method to obtain the order parameter of the chromophores at the air-liquid interface by using s- and p-polarized radiation at different incidence angles is proposed. This method allowed for the first time the experimental observation of the two components with different polarization properties of a single UV-Vis band at the air-liquid interface. The method of UV-Vis spectroscopy under variable angle incidence is presented as a new tool for obtaining rich detailed information on Langmuir monolayers.

  4. Biofilm formation at the solid-liquid and air-liquid interfaces by Acinetobacter species

    Directory of Open Access Journals (Sweden)

    Seifert Harald

    2011-01-01

    Full Text Available Abstract Background The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections. Among them, Acinetobacter baumannii has emerged as the most common pathogenic species involved in hospital-acquired infections. One reason for this emergence may be its persistence in the hospital wards, in particular in the intensive care unit; this persistence could be partially explained by the capacity of these microorganisms to form biofilm. Therefore, our main objective was to study the prevalence of the two main types of biofilm formed by the most relevant Acinetobacter species, comparing biofilm formation between the different species. Findings Biofilm formation at the air-liquid and solid-liquid interfaces was investigated in different Acinetobacter spp. and it appeared to be generally more important at 25°C than at 37°C. The biofilm formation at the solid-liquid interface by the members of the ACB-complex was at least 3 times higher than the other species (80-91% versus 5-24%. In addition, only the isolates belonging to this complex were able to form biofilm at the air-liquid interface; between 9% and 36% of the tested isolates formed this type of pellicle. Finally, within the ACB-complex, the biofilm formed at the air-liquid interface was almost 4 times higher for A. baumannii and Acinetobacter G13TU than for Acinetobacter G3 (36%, 27% & 9% respectively. Conclusions Overall, this study has shown the capacity of the Acinetobacter spp to form two different types of biofilm: solid-liquid and air-liquid interfaces. This ability was generally higher at 25°C which might contribute to their persistence in the inanimate hospital environment. Our work has also demonstrated for the first time the ability of the members of the ACB-complex to form biofilm at the air-liquid interface, a feature that was not

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

    Science.gov (United States)

    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.

  6. In vitro toxicity testing of cigarette smoke based on the air-liquid interface exposure: A review.

    Science.gov (United States)

    Li, Xiang

    2016-10-01

    Cigarette smoke is a complex aerosol comprising particulate phase and gaseous vapour phase. The air-liquid interface exposure provides a possible technical means to implement whole smoke exposure for the assessment of tobacco products. In this review, the research progress in the in vitro toxicity testing of cigarette smoke based on the air-liquid interface exposure is summarized. The contents presented involve mainly cytotoxicity, genotoxicity, oxidative stress, inflammation, systems toxicology, 3D culture and cigarette smoke dosimetry related to cigarette smoke, as well as the assessment of electronic cigarette aerosol. Prospect of the application of the air-liquid interface exposure method in assessing the biological effects of tobacco smoke is discussed.

  7. An Air-Liquid Interface Culture System for 3D Organoid Culture of Diverse Primary Gastrointestinal Tissues.

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    Li, Xingnan; Ootani, Akifumi; Kuo, Calvin

    2016-01-01

    Conventional in vitro analysis of gastrointestinal epithelium usually relies on two-dimensional (2D) culture of epithelial cell lines as monolayer on impermeable surfaces. However, the lack of context of differentiation and tissue architecture in 2D culture can hinder the faithful recapitulation of the phenotypic and morphological characteristics of native epithelium. Here, we describe a robust long-term three-dimensional (3D) culture methodology for gastrointestinal culture, which incorporates both epithelial and mesenchymal/stromal components into a collagen-based air-liquid interface 3D culture system. This system allows vigorously expansion of primary gastrointestinal epithelium for over 60 days as organoids with both proliferation and multilineage differentiation, indicating successful long-term intestinal culture within a microenvironment accurately recapitulating the stem cell niche.

  8. An electrical conductivity based method of determining the particle deposition rate in air-liquid interface devices.

    Science.gov (United States)

    Wiegand, Harald; Meyer, Jörg; Kasper, Gerhard

    2015-08-01

    A new in-situ method of determining the particle deposition rate onto cell cultures inside air-liquid interface devices is described. It is based on depositing a surrogate aerosol of salt particles onto the water filled wells of a culture plate while measuring the resulting change in electrical conductivity of the solution in situ, in order to derive the accumulated particle mass. For evaluation purposes, the wells of a six-well cell culture plate were equipped with custom designed electrodes and calibrated with a series of commercially available standard solutions. After the necessary corrections prescribed by theory, the calibration resulted in an accuracy and comparability between cells of ±3% in terms of measured conductivity. The method was then applied to a specific ALI device consisting essentially of the calibrated six-well culture plate inside an electrostatic cross-flow precipitator, and tested with submicron NaCl aerosol of defined size distribution produced by nebulization of a salt solution. 2h of particle accumulation were sufficient to accumulate between 30 and 10 μg of salt per well, depending on the location in the precipitator. Resulting deposition rates varied narrowly between the wells by about 2 ng min(-1) cm(-2). Factors affecting the overall accuracy and reproducibility are discussed.

  9. 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...

  10. Validation of an air-liquid interface toxicological set-up using Cu, Pd, and Ag well-characterized nanostructured aggregates and spheres

    Science.gov (United States)

    Svensson, C. R.; Ameer, S. S.; Ludvigsson, L.; Ali, N.; Alhamdow, A.; Messing, M. E.; Pagels, J.; Gudmundsson, A.; Bohgard, M.; Sanfins, E.; Kåredal, M.; Broberg, K.; Rissler, J.

    2016-04-01

    Systems for studying the toxicity of metal aggregates on the airways are normally not suited for evaluating the effects of individual particle characteristics. This study validates a set-up for toxicological studies of metal aggregates using an air-liquid interface approach. The set-up used a spark discharge generator capable of generating aerosol metal aggregate particles and sintered near spheres. The set-up also contained an exposure chamber, The Nano Aerosol Chamber for In Vitro Toxicity (NACIVT). The system facilitates online characterization capabilities of mass mobility, mass concentration, and number size distribution to determine the exposure. By dilution, the desired exposure level was controlled. Primary and cancerous airway cells were exposed to copper (Cu), palladium (Pd), and silver (Ag) aggregates, 50-150 nm in median diameter. The aggregates were composed of primary particles Viability was measured by WST-1 assay, cytokines (Il-6, Il-8, TNF-a, MCP) by Luminex technology. Statistically significant effects and dose response on cytokine expression were observed for SAEC cells after exposure to Cu, Pd, or Ag particles. Also, a positive dose response was observed for SAEC viability after Cu exposure. For A549 cells, statistically significant effects on viability were observed after exposure to Cu and Pd particles. The set-up produced a stable flow of aerosol particles with an exposure and dose expressed in terms of number, mass, and surface area. Exposure-related effects on the airway cellular models could be asserted.

  11. Self-Assembling of Colloidal Particles Dispersed in Mixture of Ethanol and Water at the Air-Liquid Interface of Colloidal Suspension at Room Temperature

    Institute of Scientific and Technical Information of China (English)

    WANG Ai-Jun; CHEN Sheng-Li; DONG Peng; ZHOU Qian; YUAN Gui-Mei; SU Gu-Cong

    2009-01-01

    Self-assembling of colloidal particles dispersed in a mixture of ethanol and water at the air-liquid interface of the colloidal suspension at room temperature is investigated,and a method of rapidly assembling colloidal particles is proposed.By this method,a uniform colloidal crystal thin 61m over ten square centimeters in area can be fabricated in 10 min without special facilities and heating the suspension.SEM images and a normal incidence transmission spectrum of the sample show that the colloidal crystal film fabricated by this method is of high quality.In addition,this method is very suitable for fabricating colloidal crystal heterostructures.

  12. A method to form semiconductor quantum dot (QD) thin films by igniting a flame at air-liquid interface: CdS and WO3.

    Science.gov (United States)

    Jadhav, Aarti H; Patil, Sagar H; Sathaye, Shivaram D; Patil, Kashinath R

    2015-02-01

    We reveal an easy, inexpensive, efficient one stepflame synthesis of semiconductor/metal oxide thin films at air-liquid interface, subsequently, transferred on suitable substrate. The method has been illustrated by the formation of CdS and WO3 QDs thin films. The features of the present method are (1) Growth of thin films consisting of0.5-2.0nm sized Quantum Dots (QDs)/(ultra-small nanoparticles) in a short time, at the air-liquid interface which can be suitably transferred by a well-known Blodgett technique to an appropriate substrate, (2) The method is suitable to apply layer by layer (LbL) technique to increase the film thickness as well as forming various compositions as revealed by AFM measurements. The films are characterized for their structure (SAED), morphology (TEM), optical properties (UV-Vis.) and photoluminescence (PL). Possible mechanism of formation of QDs thin film and effect of capping in case of CdS QDs is discussed.

  13. Effects of aggregates on mixed adsorption layers of poly(ethylene imine) and sodium dodecyl sulfate at the air/liquid interface.

    Science.gov (United States)

    Tonigold, Katrin; Varga, Imre; Nylander, Tommy; Campbell, Richard A

    2009-04-07

    We have exploited the spatial and kinetic resolution of ellipsometry to monitor the lateral movement of inhomogeneous patches of material in mixed adsorption layers of poly(ethylene imine) and sodium dodecyl sulfate at the air/liquid interface. We show that the choice of sample preparation methods can have a profound effect on the state of the interface for chemically equivalent samples. The extent of aggregation in the bulk solution on relevant time scales is affected by specific details of the polymer/surfactant mixing process, which produces varying numbers of aggregates that can become trapped in the interfacial layer, resulting in an enhanced and fluctuating ellipsometry signal. It can be beneficial to apply the surface-cleaning method of aspiration prior to physical measurements to remove trapped aggregates through the creation of a fresh interface. At low pH, the ellipsometry signal of samples prepared with surface cleaning is remarkably constant over a factor of >500 in the bulk composition below charge equivalence, which is discussed in terms of possible adsorption mechanisms. At high pH, through observing temporal fluctuations in the ellipsometry signal of samples prepared with surface cleaning, we reveal two important processes: there is the spontaneous adsorption of aggregates > 0.2 microm in diameter into the interfacial layer, and with time there is the fusion of smaller aggregates to generate new large surface aggregates. We attribute the favorability of the adsorption and fusion processes at high pH to reduced electrostatic barriers resulting from the low surface charge density of the aggregates. It is inappropriate in this case to consider the interface to comprise a homogeneous adsorption layer that is in dynamic equilibrium with the bulk solution. Our work shows that it can be helpful to consider whether there are macroscopic particles embedded in molecular layers at the air/liquid interface for systems where there is prior knowledge of

  14. Anomalous effective polarity of an air/liquid-mixture interface: a heterodyne-detected electronic and vibrational sum frequency generation study.

    Science.gov (United States)

    Mondal, Sudip Kumar; Inoue, Ken-ichi; Yamaguchi, Shoichi; Tahara, Tahei

    2015-10-07

    We study the effective polarity of an air/liquid-mixture interface by using interface-selective heterodyne-detected electronic sum frequency generation (HD-ESFG) and vibrational sum frequency generation (HD-VSFG) spectroscopies. With water and N,N-dimethylformamide (DMF) chosen as two components of the liquid mixture, the bulk polarity of the mixture is controlled nearly arbitrarily by the mixing ratio. The effective polarity of the air/mixture interface is evaluated by HD-ESFG with a surface-active solvatochromic molecule used as a polarity indicator. Surprisingly, the interfacial effective polarity of the air/mixture interface increases significantly, when the bulk polarity of the mixture decreases (i.e. when the fraction of DMF increases). Judging from the hydrogen-bond structure at the air/mixture interface clarified by HD-VSFG, this anomalous change of the interfacial effective polarity is attributed to the interface-specific solvation structure around the indicator molecule at the air/mixture interface.

  15. 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...

  16. Contact angle and adsorption energies of nanoparticles at the air-liquid interface determined by neutron reflectivity and molecular dynamics

    Science.gov (United States)

    Reguera, Javier; Ponomarev, Evgeniy; Geue, Thomas; Stellacci, Francesco; Bresme, Fernando; Moglianetti, Mauro

    2015-03-01

    Understanding how nanomaterials interact with interfaces is essential to control their self-assembly as well as their optical, electronic, and catalytic properties. We present here an experimental approach based on neutron reflectivity (NR) that allows the in situ measurement of the contact angles of nanoparticles adsorbed at fluid interfaces. Because our method provides a route to quantify the adsorption and interfacial energies of the nanoparticles in situ, it circumvents problems associated with existing indirect methods, which rely on the transport of the monolayers to substrates for further analysis. We illustrate the method by measuring the contact angle of hydrophilic and hydrophobic gold nanoparticles, coated with perdeuterated octanethiol (d-OT) and with a mixture of d-OT and mercaptohexanol (MHol), respectively. The contact angles were also calculated via atomistic molecular dynamics (MD) computations, showing excellent agreement with the experimental data. Our method opens the route to quantify the adsorption of complex nanoparticle structures adsorbed at fluid interfaces featuring different chemical compositions.Understanding how nanomaterials interact with interfaces is essential to control their self-assembly as well as their optical, electronic, and catalytic properties. We present here an experimental approach based on neutron reflectivity (NR) that allows the in situ measurement of the contact angles of nanoparticles adsorbed at fluid interfaces. Because our method provides a route to quantify the adsorption and interfacial energies of the nanoparticles in situ, it circumvents problems associated with existing indirect methods, which rely on the transport of the monolayers to substrates for further analysis. We illustrate the method by measuring the contact angle of hydrophilic and hydrophobic gold nanoparticles, coated with perdeuterated octanethiol (d-OT) and with a mixture of d-OT and mercaptohexanol (MHol), respectively. The contact angles were

  17. 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.

  18. Quantum chemical approach in the description of the amphiphile clusterization at the air/liquid and liquid/liquid interfaces with phase nature accounting. I. Aliphatic normal alcohols at the air/water interface.

    Science.gov (United States)

    Vysotsky, Yuri B; Belyaeva, Elena A; Kartashynska, Elena S; Fainerman, Valentine B; Smirnova, Natalia A

    2015-02-19

    A new model based on the quantum chemical approach is proposed to describe structural and thermodynamic parameters of clusterization for substituted alkanes at the air/liquid and liquid/liquid interfaces. The new model by the authors, unlike the previous one, proposes an explicit account of the liquid phase (phases) influence on the parameters of monomers, clusters and monolayers of substituted alkanes at the regarded interface. The calculations were carried out in the frameworks of the quantum chemical semiempirical PM3 method (Mopac 2012), using the COSMO procedure. The new model was tested in the calculations of the clusterization parameters of fatty alcohols under the standard conditions at the air/water interface. The enthalpy, Gibbs' energy and absolute entropy of formation for alcohol monomers alongside with clusterization parameters for the cluster series including the monolayer at air/water interface were calculated. In our calculations the sinkage of monomers, molecules in clusters and monolayers was varied from 1 up to 5 methylene groups. Thermodynamic parameters calculated using the proposed model for the alcohol monolayers are in a good agreement with the corresponding experimental data. However, the proposed model cannot define the most energetically preferable immersion of the monolayer molecules in the water phase.

  19. Polysaccharide films at an air/liquid and a liquid/silicon interface: effect of the polysaccharide and liquid type on their physical properties.

    Science.gov (United States)

    Taira, Yasunori; McNamee, Cathy E

    2014-11-14

    We investigated the effect of the polysaccharide type, the subphase on which the Langmuir monolayers were prepared, and the liquid in which the properties of the transferred monolayers were measured on the physical properties of the polysaccharide films at an air/aqueous interface and at a silicon substrate, and the forces and friction of the polysaccharide transferred films when measured in solution against a silica probe. Chitosan was modified with a silane coupling agent to make chitosan derived compounds with a low and a medium molecular weight. Chitin and the chitosan-derived compounds were used to make Langmuir monolayers at air/water and air/pH 9 buffer interfaces. The monolayers were transferred to silicon substrates via Langmuir-Blodgett deposition, and the chitosan-derived compounds subsequently chemically reacted with the silicon substrates. Atomic force microscope force and friction measurements were made in water and in the pH 9 buffer, where the water and the pH 9 buffer acted as a good and a bad solvent for the polysaccharides, respectively. The polysaccharide type affected the friction of the polysaccharide film, where the physically adsorbed chitin gave the lowest friction. The friction of L-chitosan was higher than that of M-chitosan in water, suggesting that the molecular weight of the polymer affects its lubricating ability. The forces and friction of the polysaccharide films changed when the subphase on which the Langmuir monolayers were formed was changed or when the liquid in which the properties of the films adsorbed at the silicon substrate were measured was changed. The friction increased significantly when the liquid was changed from water to the pH 9 buffer. This increase was explained by the reduced charge of the chitin and chitosan-derived materials due to the pH increase, the screening of the charges by the salts in the buffer, and the possible hardening of the monolayer caused by the adsorption of salts from the buffer.

  20. Electronic Interfacing with Living Cells

    Science.gov (United States)

    Fleming, James T.

    The direct interfacing of living cells with inorganic electronic materials, components or systems has led to the development of two broad categories of devices that can (1) transduce biochemical signals generated by biological components into electrical signals and (2) transduce electronically generated signals into biochemical signals. The first category of devices permits the monitoring of living cells, the second, enables control of cellular processes. This review will survey this exciting area with emphasis on the fundamental issues and obstacles faced by researchers. Devices and applications that use both prokaryotic (microbial) and eukaryotic (mammalian) cells will be covered. Individual devices described include microbial biofuel cells that produce electricity, bioelectrical reactors that enable electronic control of cellular metabolism, living cell biosensors for the detection of chemicals and devices that permit monitoring and control of mammalian physiology.

  1. Interfacing nanostructures to biological cells

    Science.gov (United States)

    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.

  2. Nanoporous Aluminium Oxide Membranes as Cell Interfaces

    Directory of Open Access Journals (Sweden)

    Dorothea Brüggemann

    2013-01-01

    Full Text Available Nanoporous anodic aluminium oxide (AAO has become increasingly important in biomedical applications over the past years due to its biocompatibility, increased surface area, and the possibility to tailor this nanomaterial with a wide range of surface modifications. AAO nanopores are formed in an inexpensive anodisation process of pure aluminium, which results in the self-assembly of highly ordered, vertical nanochannels with well-controllable pore diameters, depths, and interpore distances. Because of these outstanding properties AAO nanopores have become excellent candidates as nanostructured substrates for cell-interface studies. In this comprehensive review previous surveys on cell adhesion and proliferation on different AAO nanopore geometries and surface modifications are highlighted and summarised tabularly. Future applications of nanoporous alumina membranes in biotechnology and medicine are also outlined, for instance, the use of nanoporous AAO as implant modifications, coculture substrates, or immunoisolation devices.

  3. Plastic solar cell interface and morphological characterization

    Science.gov (United States)

    Guralnick, Brett W.

    Plastic solar cell research has become an intense field of study considering these devices may be lightweight, flexible and reduce the cost of photovoltaic devices. The active layer of plastic solar cells are a combination of two organic components which blend to form an internal morphology. Due to the poor electrical transport properties of the organic components it is important to understand how the morphology forms in order to engineer these materials for increased efficiency. The focus of this thesis is a detailed study of the interfaces between the plastic solar cell layers and the morphology of the active layer. The system studied in detail is a blend of P3HT and PCBM that acts as the primary absorber, which is the electron donor, and the electron acceptor, respectively. The key morphological findings are, while thermal annealing increases the crystallinity parallel to the substrate, the morphology is largely unchanged following annealing. The deposition and mixing conditions of the bulk heterojunction from solution control the starting morphology. The spin coating speed, concentration, solvent type, and solution mixing time are all critical variables in the formation of the bulk heterojunction. In addition, including the terminals or inorganic layers in the analysis is critical because the inorganic surface properties influence the morphology. Charge transfer in the device occurs at the material interfaces, and a highly resistive transparent conducting oxide layer limits device performance. It was discovered that the electron blocking layer between the transparent conducting oxide and the bulk heterojunction is compromised following annealing. The electron acceptor material can diffuse into this layer, a location which does not benefit device performance. Additionally, the back contact deposition is important since the organic material can be damaged by the thermal evaporation of Aluminum, typically used for plastic solar cells. Depositing a thin thermal and

  4. Corrosion protected, multi-layer fuel cell interface

    Science.gov (United States)

    Feigenbaum, Haim; Pudick, Sheldon; Wang, Chiu L.

    1986-01-01

    An improved interface configuration for use between adjacent elements of a fuel cell stack. The interface is impervious to gas and liquid and provides resistance to corrosion by the electrolyte of the fuel cell. The multi-layer configuration for the interface comprises a non-cupreous metal-coated metallic element to which is film-bonded a conductive layer by hot pressing a resin therebetween. The multi-layer arrangement provides bridging electrical contact.

  5. A Voronoi Interface approach to cell aggregate electropermeabilization

    Science.gov (United States)

    Guittet, Arthur; Poignard, Clair; Gibou, Frederic

    2017-03-01

    We present a Voronoi Interface approach to the study of cell electropermeabilization. We consider the nonlinear electropermeabilization model of Poignard et al. [20], which takes into account the jump in the voltage potential across cells' membrane. The jump condition is imposed in a sharp manner, using the Voronoi Interface Method of Guittet et al. [14], while adaptive Quad/Oc-tree grids are employed to automatically refine near the cells boundary for increased accuracy. Numerical results are provided to illustrate the accuracy of the methods. We also carry out simulations in three spatial dimensions to investigate the influence of shadowing and of the cells shape on the degree of permeabilization.

  6. 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

  7. Infrared modulation spectroscopy of interfaces in amorphous silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Kai; Schiff, E.A. [Department of Physics, Syracuse University, 13244-1130 Syracuse, NY (United States); Ganguly, G. [BP Solar, 23168 Toano, VA (United States)

    2002-04-01

    We report infrared depletion modulation spectra for near-interface states in a-Si pin solar cells. The effect of additional visible illumination (optical bias) was explored as a means to separate the spectra for n/i and p/i interface states. We found a sharp, optical bias-induced spectral line near 0.8 eV. We attribute this line due to internal optical transitions of dopant-defect complexes in the a-SiC:H:B p-layer of the cells. We discuss the spatial location of the depletion modulation regions, and suggest that this location shifts across the n/i and p/i interfaces for cells with differing deposition and illumination conditions.

  8. On interfaces between cell populations with different mobilities

    KAUST Repository

    Lorenzi, Tommaso

    2016-11-18

    Partial differential equations describing the dynamics of cell population densities from a fluid mechanical perspective can model the growth of avascular tumours. In this framework, we consider a system of equations that describes the interaction between a population of dividing cells and a population of non-dividing cells. The two cell populations are characterised by different mobilities. We present the results of numerical simulations displaying two-dimensional spherical waves with sharp interfaces between dividing and non-dividing cells. Furthermore, we numerically observe how different ratios between the mobilities change the morphology of the interfaces, and lead to the emergence of finger-like patterns of invasion above a threshold. Motivated by these simulations, we study the existence of one-dimensional travelling wave solutions.

  9. The air-liquid flow in a microfluidic airway tree.

    Science.gov (United States)

    Song, Yu; Baudoin, Michael; Manneville, Paul; Baroud, Charles N

    2011-09-01

    Microfluidic techniques are employed to investigate air-liquid flows in the lung. A network of microchannels with five generations is made and used as a simplified model of a section of the pulmonary airway tree. Liquid plugs are injected into the network and pushed by a flow of air; they divide at every bifurcation until they reach the exits of the network. A resistance, associated with the presence of one plug in a given generation, is defined to establish a linear relation between the driving pressure and the total flow rate in the network. Based on this resistance, good predictions are obtained for the flow of two successive plugs in different generations. The total flow rate of a two-plug flow is found to depend not only on the driving pressure and lengths of the plugs, but also the initial distance between them. Furthermore, long range interactions between daughters of a dividing plug are observed and discussed, particularly when the plugs are flowing through the bifurcations. These interactions lead to different flow patterns for different forcing conditions: the flow develops symmetrically when subjected to constant pressure or high flow rate forcing, while a low flow rate driving yields an asymmetric flow.

  10. Air Liquide's pulse tube cryocooler systems for space applications

    Science.gov (United States)

    Trollier, T.; Tanchon, J.; Rey, J. C.; Ravex, A.; Buquet, J.

    2009-05-01

    Thanks to important development efforts completed internally and with the European Space Agency (ESA) funding, Air Liquide Advanced Technology Division (AL/DTA) is now in position to propose two Pulse Tube cooler systems in the 40-80K temperature range for coming Earth Observation missions such as Meteosat Third Generation (MTG), SIFTI, etc... The Miniature Pulse Tube Cooler (MPTC) is lifting up to 2.47W@80K with 50W maximal compressor input power and 10°C rejection temperature. The weight is 2.8 kg. The Large Pulse Tube Cooler (LPTC) is providing 2.3W@50K for 160W input power and 10°C rejection temperature. This product is weighing 5.1 kg. The two pulse tube coolers thermo-mechanical units are qualified against environmental constraints as per ESA ECSS-E-30. They are both using dual opposed pistons flexure bearing compressor with moving magnet linear motors in order to ensure very high lifetime. The associated Cooler Drive Electronics is also an important aspect specifically regarding the active control of the cooler thermo-mechanical unit during the launch phase and the active reduction of the vibrations induced by the compressor (partly supported by the French Agency CNES). This paper details the presentation of the two Pulse Tube Coolers together with the Cooler Drive Electronics aspects.

  11. Interface

    DEFF Research Database (Denmark)

    Computerens interface eller grænseflade har spredt sig overalt. Mobiltelefoner, spilkonsoller, pc'er og storskærme indeholder computere – men computere indbygges også i tøj og andre hverdagslige genstande, så vi konstant har adgang til digitale data. Interface retter fokus mod, hvordan den digita...

  12. Interface engineering of Graphene-Silicon heterojunction solar cells

    Science.gov (United States)

    Xu, Dikai; Yu, Xuegong; Yang, Lifei; Yang, Deren

    2016-11-01

    Graphene has attracted great research interests due to its unique mechanical, electrical and optical properties, which opens up a huge number of opportunities for applications. Recently, Graphene-Silicon (Grsbnd Si) solar cell has been recognized as one interesting candidate for the future photovoltaic. Since the first Grsbnd Si solar cell reported in 2010, Grsbnd Si solar cell has been intensively investigated and the power converse efficiency (PCE) of it has been developed to 15.6%. This review presents and discusses current development of Grsbnd Si solar cell. Firstly, the basic concept and mechanism of Grsbnd Si solar cell are introduced. Then, several key technologies are introduced to improve the performance of Grsbnd Si solar cells, such as chemical doping, annealing, Si surface passivation and interlayer insertion. Particular emphasis is placed on strategies for Grsbnd Si interface engineering. Finally, new pathways and opportunities of "MIS-like structure" Grsbnd Si solar cells are described.

  13. interfaces

    Directory of Open Access Journals (Sweden)

    Dipayan Sanyal

    2005-01-01

    macroscopic conservation equations with an order parameter which can account for the solid, liquid, and the mushy zones with the help of a phase function defined on the basis of the liquid fraction, the Gibbs relation, and the phase diagram with local approximations. Using the above formalism for alloy solidification, the width of the diffuse interface (mushy zone was computed rather accurately for iron-carbon and ammonium chloride-water binary alloys and validated against experimental data from literature.

  14. 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.

  15. 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.)

  16. Interface reactions in CdTe solar cell processing

    Energy Technology Data Exchange (ETDEWEB)

    Albin, D.; Dhere, R.; Swartzlander-Guest, A. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1998-12-31

    Currently, the best performing CdS/CdTe solar cells use a superstrate structure in which CdTe is deposited on a heated CdS/SnO{sub 2}/Glass substrate. In the close-spaced-sublimation (CSS) process, substrate temperatures in the range 550 C to 620 C are common. Understanding how these high processing temperatures impact reactions at the CdS/CdTe interface in addition to reactions between previously deposited layers is critical. At the SnO{sub 2}/CdS interface the authors have determined that SnO{sub 2} can be susceptible to reduction, particularly in H{sub 2} ambients. Room-temperature sputtered SnO{sub 2} shows the most susceptibility. In contrast, higher growth temperature chemical vapor deposited (CVD) SnO{sub 2} appears to be much more stable. Elimination of unstable SnO{sub 2} layers, and the substitution of thermal treatments for H{sub 2} anneals has produced total-area solar conversion efficiencies of 13.6% using non-optimized SnO{sub 2} substrates and chemical-bath deposited (CBD) CdS. Alloying and interdiffusion at the CdS/CdTe interface was studied using a new lift-off approach which allows enhanced compositional and structural analysis at the interface. Small-grained CdS, grown by a low-temperature CBD process, results in more CdTe{sub 1{minus}x}S{sub x} alloying (x = 12--13%) relative to larger-grained CdS grown by high-temperature CSS (x{approximately}2--3%). Interdiffusion of S and Te at the interface, measured with lift-off samples, appears to be inversely proportional to the amount of oxygen used during the CSS CdTe deposition. The highest efficiency to date using CSS-grown CdS is 10.7% and was accomplished by eliminating oxygen during the CdTe deposition.

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

    DEFF Research Database (Denmark)

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

    1999-01-01

    here shall encompass the spontaneous separation of racemates of amphiphilic molecules into enantiomorphous two-dimensional (2D) domains, the formation of alkane multilayers, the assembly of trilayers containing interdigitated molecules, the self-organization of supramolecular thin film architectures...

  18. 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

  19. Design and Fabrication of Nanodevice for Cell Interfacing

    Science.gov (United States)

    Chinnappan, Prema

    The goal of this thesis is to (a) design and fabricate a nanodevice that interface with cells and (b) optimize neuronal cell culturing protocol. The long term objective of this thesis is to perform intracellular electrical signal recording and stimulation of neuronal cells. To achieve this objective, a nanodevice with "Fin" shaped electrodes was designed that increases the electrode area and conductance so that it reduces the signal loss as shown in the case of traditional circular Nanopillar design. The overarching goal of neuroscience is to target and discover the relationships between the functional connectivity-map of neuronal circuits and their physiological or pathological functions. For recording large number of neurons, technologies such as gold mushroom-shaped microelectrodes (Hai et al.), vertical nanowire electrode arrays (VNEAs) (Robinson et al.) and nanoFET technology (Tian et al.) are currently under development. The gold mushroom-shaped electrodes in order of microns are invasive for smaller cells with no successful recording for long durations. The VNEAs show high electrode impedance which causes large signal loss. The nanoFET shows higher noise levels and the manipulation of a single nanotube to penetrate a single cell is very challenging. This thesis presents the design and fabrication of a "Fin" shaped nanoelectrode which seeks to overcome the restrictions between electrode impedance and electrode size. Compared to the 3x3 array of 200nm diameter nanowire electrodes, the "Fin" electrodes reduces the interfacial impedance. The fabrication was done in Silicon on insulator wafer with conducting lines and contact pads completely insulated by Silicon dioxide layer and gold coated nanofins. Nanofins of width 200 nm were fabricated using Focused Ion Beam (FIB) milling. Both high density and low density nanofins were optimized and cells were cultured over them. The optimization of cell culture, adherence and differentiation protocols were done to grow

  20. 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.

  1. 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.

  2. Interface and Composition Analysis on Perovskite Solar Cells.

    Science.gov (United States)

    Matteocci, Fabio; Busby, Yan; Pireaux, Jean-Jacques; Divitini, Giorgio; Cacovich, Stefania; Ducati, Caterina; Di Carlo, Aldo

    2015-12-02

    Organometal halide (hybrid) perovskite solar cells have been fabricated following four different deposition procedures and investigated in order to find correlations between the solar cell characteristics/performance and their structure and composition as determined by combining depth-resolved imaging with time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), and analytical scanning transmission electron microscopy (STEM). The interface quality is found to be strongly affected by the perovskite deposition procedure, and in particular from the environment where the conversion of the starting precursors into the final perovskite is performed (air, nitrogen, or vacuum). The conversion efficiency of the precursors into the hybrid perovskite layer is compared between the different solar cells by looking at the ToF-SIMS intensities of the characteristic molecular fragments from the perovskite and the precursor materials. Energy dispersive X-ray spectroscopy in the STEM confirms the macroscopic ToF-SIMS findings and allows elemental mapping with nanometer resolution. Clear evidence for iodine diffusion has been observed and related to the fabrication procedure.

  3. 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

  4. 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...

  5. Modeling of the cell-electrode interface noise for microelectrode arrays.

    Science.gov (United States)

    Guo, Jing; Yuan, Jie; Chan, Mansun

    2012-12-01

    Microelectrodes are widely used in the physiological recording of cell field potentials. As microelectrode signals are generally in the μV range, characteristics of the cell-electrode interface are important to the recording accuracy. Although the impedance of the microelectrode-solution interface has been well studied and modeled in the past, no effective model has been experimentally verified to estimate the noise of the cell-electrode interface. Also in existing interface models, spectral information is largely disregarded. In this work, we developed a model for estimating the noise of the cell-electrode interface from interface impedances. This model improves over existing noise models by including the cell membrane capacitor and frequency dependent impedances. With low-noise experiment setups, this model is verified by microelectrode array (MEA) experiments with mouse muscle myoblast cells. Experiments show that the noise estimated from this model has models. With this model, noise of the cell-electrode interface can be estimated by simply measuring interface impedances. This model also provides insights for micro- electrode design to achieve good recording signal-to-noise ratio.

  6. Comparative SAXS and DSC study on stratum corneum structural organization in an epidermal cell culture model (ROC)

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Herre, Angela; Fahr, Alfred

    2013-01-01

    Cell cultured skin equivalents present an alternative for dermatological in vitro evaluations of drugs and excipients as they provide the advantage of availability, lower variability and higher assay robustness compared to native skin. For penetration/permeation studies, an adequate stratum corneum...... barrier similar to that of human stratum corneum is, however, a prerequisite. In this study, the stratum corneum lipid organization in an epidermal cell culture model based on rat epidermal keratinocytes (REK organotypic culture, ROC) was investigated by small-angle X-ray scattering (SAXS) in dependence...... of ROC SC obtained at different cultivation times (7, 14 and 21days at the air-liquid interface) was connected with an increase in structural order of the SC lipids in SAXS measurements: Already cultivation for 14days at the air-liquid interface resulted overall in a competent SC permeability barrier...

  7. Initial formation and development of CdS/CuInSe2 solar cell interfaces

    Science.gov (United States)

    Kazmerski, L. L.; Russell, P. E.; Jamjoum, O.; Ireland, P. J.; Matson, R. J.; Hermann, A.; Ahrenkiel, R. K.; Mickelsen, R. A.; Chen, W. S.; Bachmann, K. J.

    Fundamental properties of interface formation in the CdS and Cd(Zn)S/CuInSe2 solar cell are investigated using surface analysis and microelectrical characterizations. The formation of a binary semiconductor transition layer during the initial stages of heterojunction growth is reported. The effects of annealing on the integrity of the various device interfaces and the performance of the cells are discussed. The evaluation of heterojunction and electrical response at other internal interfaces is studied using high resolution EBIC on fractured cell cross-sections. The importance and effects of post-deposition oxygen heat-treatments on the cell performance are discussed.

  8. Numerical simulation of red blood cell suspensions behind a moving interface in a capillary

    CERN Document Server

    Zhao, Shihai

    2013-01-01

    Computational modeling and simulation are presented on the motion of red blood cells behind a moving interface in a capillary. The methodology is based on an immersed boundary method and the skeleton structure of the red blood cell (RBC) membrane is modeled as a spring network. The computational domain is moving with either a designated RBC or an interface in an infinitely long two-dimensional channel with an undisturbed flow field in front of the domain. The tanking-treading and the inclination angle of a cell in a simple shear flow are briefly discussed for the validation purpose. We then present the results of the motion of red blood cells behind a moving interface in a capillary, which show that the RBCs with higher velocity than the interface speed form a concentrated slug behind the interface.

  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. 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.

  11. Recent progress in interface modification for dye-sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Interface modification on the TiO2/dye/electrolyte interface of dye-sensitized solar cells (DSCs) is one of the most effective approaches to suppress the charge recombination,improve electron injection and transportation,and thus ameliorate the conversion efficiency and stability of DSCs.Conventional research focusing on the photoanodes interface modification before sensitization in dye-sensitized solar cells has been carried out and reviewed.However,recent studies showed that post-modification after sensitization of the TiO2 electrode also plays a significant role on the TiO2/dye/electrolyte interface.This post-modification using the immersing method could deprotonate dye molecules,prohibit the dye aggregation and retard the recombination reaction.As a result,it has great influence on the devices’ photovoltaic performance.This interface modification could also provide an approach to broaden the response of the solar spectrum by introducing an alternative assembling structure.An in-situ meaning of using a co-adsorbent is employed to modify the interface in the DSCs,which could retard the aggregation of the dye molecules and enhance the conversion efficiency.In addition,electrolyte additives can be used to modify the TiO2/dye/electrolyte interface through some unique mechanisms.Based on the background of interface modification of photoanodes before sensitization,this review introduces various interface modifications after sensitization of dye-sensitized solar cells and their mechanisms.

  12. 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...

  13. Carrier collection losses in interface passivated amorphous silicon thin-film solar cells

    Science.gov (United States)

    Neumüller, A.; Bereznev, S.; Ewert, M.; Volobujeva, O.; Sergeev, O.; Falta, J.; Vehse, M.; Agert, C.

    2016-07-01

    In silicon thin-film solar cells the interface between the i- and p-layer is the most critical. In the case of back diffusion of photogenerated minority carriers to the i/p-interface, recombination occurs mainly on the defect states at the interface. To suppress this effect and to reduce recombination losses, hydrogen plasma treatment (HPT) is usually applied. As an alternative to using state of the art HPT we apply an argon plasma treatment (APT) before the p-layer deposition in n-i-p solar cells. To study the effect of APT, several investigations were applied to compare the results with HPT and no plasma treatment at the interface. Carrier collection losses in resulting solar cells were examined with spectral response measurements with and without bias voltage. To investigate single layers, surface photovoltage and X-ray photoelectron spectroscopy (XPS) measurements were conducted. The results with APT at the i/p-interface show a beneficial contribution to the carrier collection compared with HPT and no plasma treatment. Therefore, it can be concluded that APT reduces the recombination centers at the interface. Further, we demonstrate that carrier collection losses of thin-film solar cells are significantly lower with APT.

  14. 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...

  15. Smart interface materials integrated with microfluidics for on-demand local capture and release of cells.

    Science.gov (United States)

    Gurkan, Umut Atakan; Tasoglu, Savas; Akkaynak, Derya; Avci, Oguzhan; Unluisler, Sebnem; Canikyan, Serli; Maccallum, Noah; Demirci, Utkan

    2012-09-01

    Stimuli responsive, smart interface materials are integrated with microfluidic technologies creating new functions for a broad range of biological and clinical applications by controlling the material and cell interactions. Local capture and on-demand local release of cells are demonstrated with spatial and temporal control in a microfluidic system.

  16. 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...

  17. Le financement d'une start-up:L'Air Liquide 1898 - 1913

    OpenAIRE

    2003-01-01

    (VF)Au début du 20e siècle, L'air Liquide est une jeune entreprise française créée pour appliquer à l'échelle industrielle les découvertes de la chimie minérale : la liquéfaction de l'air. Les différentes étapes du financement de cette "start-up" ou "société en germe de développement" à l'époque, sont analysées dans le contexte d'incertitude sur la technologie et la production future avec l'implication des différentes classes d'investisseurs et le recours au marché Over The Counter:"la Coulis...

  18. Cell membrane conformation at vertical nanowire array interface revealed by fluorescence imaging

    Science.gov (United States)

    Berthing, Trine; Bonde, Sara; Rostgaard, Katrine R.; Hannibal Madsen, Morten; Sørensen, Claus B.; Nygård, Jesper; Martinez, Karen L.

    2012-10-01

    The perspectives offered by vertical arrays of nanowires for biosensing applications in living cells depend on the access of individual nanowires to the cell interior. Recent results on electrical access and molecular delivery suggest that direct access is not always obtained. Here, we present a generic approach to directly visualize the membrane conformation of living cells interfaced with nanowire arrays, with single nanowire resolution. The method combines confocal z-stack imaging with an optimized cell membrane labelling strategy which was applied to HEK293 cells interfaced with 2-11 μm long and 3-7 μm spaced nanowires with various surface coatings (bare, aminosilane-coated or polyethyleneimine-coated indium arsenide). We demonstrate that, for all commonly used nanowire lengths, spacings and surface coatings, nanowires generally remain enclosed in a membrane compartment, and are thereby not in direct contact with the cell interior.

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

    DEFF Research Database (Denmark)

    Tavares, Fernando Menezes Leitão

    . 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 massive number of small...... cells, especially indoors, is expected to provide the largest improvement in network capacity. However, the benefits of this type of ultra-dense deployment do not come for free; strong inter-cell interference, an inherent problem of dense networks, has the potential to limit the expected gains. Due...... robustness is achieved by the clever design of the radio frame structure in such a way that interference suppression receivers can efficiently and effectively mitigate the effects of inter-cell interference. A detailed receiver model is derived (including also receiver imperfections, such as estimation...

  20. Spin Coated Plasmonic Nanoparticle Interfaces for Photocurrent Enhancement in Thin Film Si Solar Cells

    Directory of Open Access Journals (Sweden)

    Miriam Israelowitz

    2014-01-01

    Full Text Available Nanoparticle (NP arrays of noble metals strongly absorb light in the visible to infrared wavelengths through resonant interactions between the incident electromagnetic field and the metal’s free electron plasma. Such plasmonic interfaces enhance light absorption and photocurrent in solar cells. We report a cost-effective and scalable room temperature/pressure spin-coating route to fabricate broadband plasmonic interfaces consisting of silver NPs. The NP interface yields photocurrent enhancement (PE in thin film silicon devices by up to 200% which is significantly greater than previously reported values. For coatings produced from Ag nanoink containing particles with average diameter of 40 nm, an optimal NP surface coverage ϕ of 7% is observed. Scanning electron microscopy of interface morphologies revealed that for low ϕ, particles are well separated, resulting in broadband PE. At higher ϕ, formation of particle strings and clusters causes red-shifting of the PE peak and a narrower spectral response.

  1. Photovoltaics. Interface engineering of highly efficient perovskite solar cells.

    Science.gov (United States)

    Zhou, Huanping; Chen, Qi; Li, Gang; Luo, Song; Song, Tze-bing; Duan, Hsin-Sheng; Hong, Ziruo; You, Jingbi; Liu, Yongsheng; Yang, Yang

    2014-08-01

    Advancing perovskite solar cell technologies toward their theoretical power conversion efficiency (PCE) requires delicate control over the carrier dynamics throughout the entire device. By controlling the formation of the perovskite layer and careful choices of other materials, we suppressed carrier recombination in the absorber, facilitated carrier injection into the carrier transport layers, and maintained good carrier extraction at the electrodes. When measured via reverse bias scan, cell PCE is typically boosted to 16.6% on average, with the highest efficiency of ~19.3% in a planar geometry without antireflective coating. The fabrication of our perovskite solar cells was conducted in air and from solution at low temperatures, which should simplify manufacturing of large-area perovskite devices that are inexpensive and perform at high levels.

  2. 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.

  3. Optimization of Organic Solar Cells: Materials, Devices and Interfaces

    Science.gov (United States)

    Zhou, Nanjia

    Due to the increasing demand for sustainable clean energy, photovoltaic cells have received intensified attention in the past decade in both academia and industry. Among the types of cells, organic photovoltaic (OPV) cells offer promise as alternatives to conventional inorganic-type solar cells owning to several unique advantages such as low material and fabrication cost. To maximize power conversion efficiencies (PCEs), extensive research efforts focus on frontier molecular orbital (FMO) energy engineering of photoactive materials. Towards this objective, a series of novel donor polymers incorporating a new building block, bithiophene imide (BTI) group are developed, with narrow bandgap and low-lying highest occupied molecular orbital (HOMO) energies to increase short circuit current density, Jsc, and open circuit voltage, Voc.. Compared to other PV technologies, OPVs often suffer from large internal recombination loss and relatively low fill factors (FFs) thin film morphology, OPVs with PCEs up to 8.7% and unprecedented FF approaching 80% are obtained. Such high FF are close to those typically achieved in amorphous Si solar cells. Systematic variations of polymer chemical structures lead to understanding of structure-property relationships between polymer geometry and the resulting blend film morphology characteristics which are crucial for achieving high local mobilities and long carrier lifetimes. Instead of using fullerene as the acceptors, an alternative type of OPV is developed employing a high electron mobility polymer, P(NDI2OD-T2), as the acceptor. To improve the all-polymer blend film morphology, the influence of basic solvent properties such as solvent boiling point and solubility on polymer phase separation and charge transport properties is investigated, yielding to a high PCE of 2.7% for all-polymer solar cells. To take advantages of the inherent mechanical flexibility associated with organic materials, the development of transparent, flexible

  4. Organic and perovskite solar cells: Working principles, materials and interfaces.

    Science.gov (United States)

    Marinova, Nevena; Valero, Silvia; Delgado, Juan Luis

    2017-02-15

    In the last decades organic solar cells (OSCs) have been considered as a promising photovoltaic technology with the potential to provide reasonable power conversion efficiencies combined with low cost and easy processability. Unexpectedly, Perovskite Solar Cells (PSCs) have experienced unprecedented rise in Power Conversion Efficiency (PCE) thus emerging as a highly efficient photovoltaic technology. OSCs and PSCs are two different kind of devices with distinct charge generation mechanism, which however share some similarities in the materials processing, thus standard strategies developed for OSCs are currently being employed in PSCs. In this article, we recapitulate the main processes in these two types of photovoltaic technologies with an emphasis on interfacial processes and interfacial modification, spotlighting the materials and newest approaches in the interfacial engineering. We discuss on the relevance of well-known materials coming from the OSCs field, which are now being tested in the PSCs field, while maintaining a focus on the importance of the material design for highly efficient, stable and accessible solar cells.

  5. Evaluating effect of surface state density at the interfaces in degraded bulk heterojunction organic solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Swati, E-mail: drswatia@yahoo.com [Department of Physics, Zakir Husain College, University of Delhi, Delhi 110002 (India); Singh, Vinamrita [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Arora, Manoj [Department of Physics, Ramjas College, University of Delhi, Delhi 110007 (India); Pal Tandon, Ram [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2012-08-01

    Degradation and short shelf life have been observed experimentally in poly(3-hexylthiophene) (P3HT): 6,6-phenyl C61-butyric acid methyl ester (PCBM) based blend solar cells. Both dark and illuminated current-voltage characteristics could be explained quantitatively with a proposed single model for a typical degraded organic solar cell-glass/ITO/PEDOT:PSS/P3HT:PCBM/Al. It has been found that surface state density, interface thickness, tunneling coefficient and occupation probabilities of the interface states becomes important with the passage of time. To look into the problem the activity at ITO/PEDOT:PSS and P3HT:PCBM/Al interfaces are studied using realistic values of the interfaces. The experimental J-V characteristics is well explained with the inclusion of tunneling current through these surface states and becomes the dominant current component for the degraded cell. It is also found that surface state density increases to 10{sup 12}-10{sup 13} cm{sup -2} eV{sup -1}, which has been verified with C-V measurements and also is in agreement with our proposed model for BHJ solar cell after 150 h of fabrication.

  6. The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures.

    Science.gov (United States)

    Gerlach, D; Wimmer, M; Wilks, R G; Félix, R; Kronast, F; Ruske, F; Bär, M

    2014-12-21

    The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization.

  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.

    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.

  8. Interface dermatitis

    Directory of Open Access Journals (Sweden)

    Rajiv Joshi

    2013-01-01

    Full Text Available Interface dermatitis includes diseases in which the primary pathology involves the dermo-epidermal junction. The salient histological findings include basal cell vacuolization, apoptotic keratinocytes (colloid or Civatte bodies, and obscuring of the dermo-epidermal junction by inflammatory cells. Secondary changes of the epidermis and papillary dermis along with type, distribution and density of inflammatory cells are used for the differential diagnoses of the various diseases that exhibit interface changes. Lupus erythematosus, dermatomyositis, lichen planus, graft versus host disease, erythema multiforme, fixed drug eruptions, lichen striatus, and pityriasis lichenoides are considered major interface diseases. Several other diseases (inflammatory, infective, and neoplastic may show interface changes.

  9. A Hybrid Immersed Boundary-Immersed Interface Method for Cell Tracking in Microdevices

    Science.gov (United States)

    Hossan, Mohammad; Dutta, Prashanta; Dillon, Robert

    2011-11-01

    The manipulation of cells in microfluidic devices has become routine for biomedical applications such as cell sorting and trapping. To date most of the designs used for cell manipulation are based on experimental trial and error. A fast and accurate numerical algorithm can provide important insight into the design of these devices. In this study, a hybrid immersed boundary-immersed interface method is developed to study the complex behavior of cells in liquid. The immersed boundary method provides an accurate prediction of particle motion in a fluid while the immersed interface method gives second-order accurate solutions for the ion concentrations and electrostatic potential in the presence of moving cells. Both methods employ a fixed computational grid without the need for remeshing at each time step. Cells of different size, shape and charge are allowed to move under both hydrodynamic and electrokinetic forces. Moreover different channel geometries are considered to obtain the best trapping and separation performance. The present immersed boundary-immersed interface model is particularly suitable for bioMEMS devices as this method can accurately predict viscous and electrostatic forces as well as particle velocity, location, and particle membrane deflection.

  10. 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.

  11. 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.

  12. 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.

  13. Ab initio Description of Optoelectronic Properties at Defective Interfaces in Solar Cells

    CERN Document Server

    Czaja, Philippe; Giusepponi, Simone; Gusso, Michele; Aeberhard, Urs

    2016-01-01

    In order to optimize the optoelectronic properties of novel solar cell architectures, such as the amorphous-crystalline interface in silicon heterojunction devices, we calculate and analyze the local microscopic structure at this interface and in bulk a-Si:H, in particular with respect to the impact of material inhomogeneities. The microscopic information is used to extract macroscopic material properties, and to identify localized defect states, which govern the recombination properties encoded in quantities such as capture cross sections used in the Shockley-Read-Hall theory. To this end, atomic configurations for a-Si:H and a-Si:H/c-Si interfaces are generated using molecular dynamics. Density functional theory calculations are then applied to these configurations in order to obtain the electronic wave functions. These are analyzed and characterized with respect to their localization and their contribution to the (local) density of states. GW calculations are performed for the a-Si:H configuration in order...

  14. Nano-Bio Electrochemical Interfacing-Linking Cell Biology and Micro-Electronics

    Science.gov (United States)

    Shacham-Diamand, Y.; Popovtzer, R.; Rishpon, Y.

    Integration of biological substance within electronic devices is an innovative and challenging area combining recent progress in molecular biology and micro technology. First, we introduce the concept of integrating living cells with Micro Electro Mechanical Systems (MEMS). Following a brief overview on "whole cell based biosensors" we describe the design, fabrication, and process of a biocompatible electrochemical "Lab-on-a-Chip" system. Demonstrating the application of electrochemical interfacing based whole cell bio chips, we present two different configurations: a. integration of prokaryotic cells (bacteria) for water toxicity detection, and b. integration of eukaryotic cells (human colon cancer cells) for rapid evaluation of the effectiveness of drug treatments. Both applications, with either microbes or mammalian cells integrated onto MEMS based biochips with liquid volume in the range of 100 nL-1 μL, function well and yield a detectable signal much higher than noise level after few minutes.

  15. Experimental Results Obtained with Air Liquide Cold Compression System: CERN LHC and SNS Projects

    Science.gov (United States)

    Delcayre, F.; Courty, J.-C.; Hamber, F.; Hilbert, B.; Monneret, E.; Toia, J.-L.

    2006-04-01

    Large scale collider facilities will make intensive use of superconducting magnets, operating below 2.0 K. This dictates high-capacity refrigeration systems operating below 2.0 K. These systems, making use of cryogenic centrifugal compressors in a series arrangement with room temperature screw compressors will be coupled to a refrigerator, providing a certain power at 4.5 K. A first Air Liquide Cold Compression System (CCS) unit was built and delivered to CERN in 2001. Installed at the beginning of 2002, it was commissioned and tested successfully during year 2002. A series of four sets of identical CCS were then tested in 2004. Another set of four cryogenic centrifugal compressors (CCC) has been delivered to Thomas Jefferson National Accelerator Facility (JLAB) for the Spallation Neutron Source (SNS) in 2002. These compressors were tested and commissioned from December 2004 to July 2005. The experimental results obtained with these systems will be presented and discussed: the characteristics of the CCC will be detailed. The principles of control for the CCC in series will be detailed.

  16. 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.

  17. 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.

  18. Versatile dual organic interface layer for performance enhancement of polymer solar cells

    Science.gov (United States)

    Li, Zhiqi; Liu, Chunyu; Zhang, Zhihui; Li, Jinfeng; Zhang, Liu; Zhang, Xinyuan; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2016-11-01

    The electron transport layer plays a crucial role on determining electron injection and extraction, resulting from the effect of balancing charge transport and reducing the interfacial energy barrier. Decreasing the inherent incompatibility and enhancing electrical contact via employing appropriate buffer layer at the surface of hydrophobic organic active layer and hydrophilic inorganic electrode are also essential for charge collection. Herein, we demonstrate that an efficient dual polyelectrolytes interfacial layer composed of polyethylenimine (PEI) and conducting poly(9,9-dihexylfluorenyl-2,7-diyl) (PDHFD) is incorporated to investigate the interface energetics and electron transport in polymer solar cells (PSCs). The composited PEI/PDHFD interface layer (PPIL) overcomed the low conductivity of bare PEI polymer, which decreased series resistance and facilitated electron extraction at the ITO/PPIL-active layer interface. The introduction of the interface energy state of the PPIL reduced the work function of ITO so that it can mate the top of the valence band of the photoactive materials and promoted the formation of ohmic contact at ITO electrode interface. As a result, the composited PPIL tuned energy alignment and accelerated the electron transfer, leading to significantly increased photocurrent and power conversion efficiency (PCE) of the devices based on various representative polymer:fullerene systems.

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

    Institute of Scientific and Technical Information of China (English)

    ZENG Ming-Ying; CUI Wei; TAN Xiao-Qin; WU Chen-Xu

    2011-01-01

    @@ 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 surfacc 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 thcn extends to the inner space as the temperature increases.%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 nernatic 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.

  20. 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.

  1. Tuning back contact property via artificial interface dipoles in Si/organic hybrid solar cells

    Science.gov (United States)

    Wang, Dan; Sheng, Jiang; Wu, Sudong; Zhu, Juye; Chen, Shaojie; Gao, Pingqi; Ye, Jichun

    2016-07-01

    Back contact property plays a key role in the charge collection efficiency of c-Si/poly(3,4-ethylthiophene):poly(styrenesulfonate) hybrid solar cells (Si-HSCs), as an alternative for the high-efficiency and low-cost photovoltaic devices. In this letter, we utilize the water soluble poly (ethylene oxide) (PEO) to modify the Al/Si interface to be an Ohmic contact via interface dipole tuning, decreasing the work function of the Al film. This Ohmic contact improves the electron collection efficiency of the rear electrode, increasing the short circuit current density (Jsc). Furthermore, the interface dipoles make the band bending downward to increase the total barrier height of built-in electric field of the solar cell, enhancing the open circuit voltage (Voc). The PEO solar cell exhibits an excellent performance, 12.29% power conversion efficiency, a 25.28% increase from the reference solar cell without a PEO interlayer. The simple and water soluble method as a promising alternative is used to develop the interfacial contact quality of the rear electrode for the high photovoltaic performance of Si-HSCs.

  2. Soft X-rays shedding light on thin-film solar cell surfaces and interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bär, M., E-mail: marcus.baer@helmholtz-berlin.de [Solar Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), D-14109 Berlin (Germany); Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus, D-03046 Cottbus (Germany); Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Pookpanratana, S. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Weinhardt, L. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen (Germany); ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen (Germany); Wilks, R.G.; Schubert, B.A.; Marsen, B.; Unold, T. [Solar Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), D-14109 Berlin (Germany); Blum, M.; Krause, S. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Zhang, Y. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Department of Physics, Xiamen University, Xiamen, Fujian 361005 (China); Ranasinghe, A. [Department of Chemistry, University of Nevada, Las Vegas (UNLV), Las Vegas, NV 89154 (United States); Ramanathan, K.; Repins, I.; Contreras, M.A. [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States); Nishiwaki, S. [Institute for Energy Conversion (IEC), University of Delaware, Newark, DE 19716 (United States); and others

    2013-10-15

    Highlights: ► S/Se gradient-driven chemical interaction at the CdS/CIG(S)Se interface. ► Depth-dependent band gap in chalcopyrites. ► Band alignment at the CdS/Cu{sub 2}ZnSnS{sub 4} solar cell heterojunction. ► Post-deposition treatment induces intermixing in the CdTe/CdS solar cell structure. -- Abstract: Thin-film solar cells based on compound semiconductors consist of a multilayer structure with various interfaces and contain a multitude of elements and impurities, etc. A rapid progress of these photovoltaic technologies can only be achieved by an insight-driven optimization/development. Hence it is crucial to characterize and understand the relationship between the chemical and electronic properties of these components. This paper reviews some examples of our recent work characterizing compound semiconductor thin films using laboratory- and synchrotron-based electron and soft X-ray spectroscopic characterization methods. It is demonstrated how these different analytical techniques are extraordinarily powerful to reveal the material characteristics from many different perspectives, ultimately resulting in a comprehensive picture of the related electronic and chemical properties. As examples, the paper will discuss the electronic surface structure of chalcopyrite thin-film solar cell absorbers, the chemical structure of the CdS/chalcopyrite interface, present the band alignment at the CdS/kesterite interface, and report on how post-deposition treatments cause chemical interaction/interdiffusion processes in CdTe/CdS thin-film solar cell structures.

  3. Indium sulfide buffer/CIGSSe interface engineering: Improved cell performance by the addition of zinc sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Allsop, N.A. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany)]. E-mail: allsop@hmi.de; Camus, C. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Haensel, A. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Gledhill, S.E. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Lauermann, I. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Lux-Steiner, M.C. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Fischer, Ch.-H. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany)

    2007-05-31

    Indium sulfide buffer layers deposited by the spray-ion layer gas reaction (Spray-ILGAR) technique are a viable alternative to the traditional cadmium sulfide buffer layer in thin film solar cells. In the present work we report on the results of manipulating the absorber/buffer interface between the chalcopyrite Cu(In,Ga)(S,Se){sub 2} absorber (CIGSSe) and the indium sulfide buffer. It is shown that the deposition of a small amount of zinc sulfide at the absorber/buffer interface can be used to increase the open circuit voltage. A small but significant increase of 20 mV (up to 580 mV), as compared to the pure indium sulfide buffered cells is possible leading to an increase in the overall efficiency.

  4. Robotics, Stem Cells and Brain Computer Interfaces in Rehabilitation and Recovery from Stroke; Updates and Advances

    Science.gov (United States)

    Boninger, Michael L; Wechsler, Lawrence R.; Stein, Joel

    2014-01-01

    Objective To describe the current state and latest advances in robotics, stem cells, and brain computer interfaces in rehabilitation and recovery for stroke. Design The authors of this summary recently reviewed this work as part of a national presentation. The paper represents the information included in each area. Results Each area has seen great advances and challenges as products move to market and experiments are ongoing. Conclusion Robotics, stem cells, and brain computer interfaces all have tremendous potential to reduce disability and lead to better outcomes for patients with stroke. Continued research and investment will be needed as the field moves forward. With this investment, the potential for recovery of function is likely substantial PMID:25313662

  5. Interface Characterization of Single-Crystal CdTe Solar Cells With VOC > 950 mV

    Energy Technology Data Exchange (ETDEWEB)

    Burst, James M.; Duenow, Joel N.; Kanevce, Ana; Moutinho, Helio R.; Jiang, Chun Sheng; Al-Jassim, Mowafak M.; Reese, Matthew Owen; Albin, David S.; Aguiar, Jeffrey A.; Colegrove, Eric; Ablekim, Tursun; Swain, Santosh K.; Lynn, Kelvin G.; Kuciauskas, Darius; Barnes, Teresa M.; Metzger, Wyatt K.

    2016-11-01

    Advancing CdTe solar cell efficiency requires improving the open-circuit voltage (VOC) above 900 mV. This requires long carrier lifetime, high hole density, and high-quality interfaces, where the interface recombination velocity is less than about 104 cm/s. Using CdTe single crystals as a model system, we report on CdTe/CdS electrical and structural interface properties in devices that produce open-circuit voltage exceeding 950 mV.

  6. Interfaces in Dye-Sensitized Oxide / Hole-Conductor Heterojunctions for Solar Cell Applications

    OpenAIRE

    Johansson, Erik

    2006-01-01

    Nanoporous dye-sensitized solar cells (DSSC) are promising devices for solar to electric energy conversion. In this thesis photoelectron spectroscopy (PES), x-ray absorption spectroscopy (XAS) and photovoltaic measurements are used for studies of the key interfaces in the DSSC. Photovoltaic properties of new combinations of TiO2/dye/hole-conductor heterojunctions were demonstrated and their interfacial structures were studied. Three different types of hole-conductor materials were investigate...

  7. Mathematical modeling of channel-porous layer interfaces in PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ehrhardt, M.; Fuhrmann, J.; Holzbecher, E.; Linke, A.

    2008-07-01

    In proton exchange membrane (PEM) fuel cells, the transport of the fuel to the active zones, and the removal of the reaction products are realized using a combination of channels and porous diffusion layers. In order to improve existing mathematical and numerical models of PEM fuel cells, a deeper understanding of the coupling of the flow processes in the channels and diffusion layers is necessary. After discussing different mathematical models for PEM fuel cells, the work focuses on the description of the coupling of the free flow in the channel region with the filtration velocity in the porous diffusion layer as well as interface conditions between them. The difficulty in finding effective coupling conditions at the interface between the channel flow and the membrane lies in the fact that often the orders of the corresponding differential operators are different, e.g., when using stationary (Navier-)Stokes and Darcy's equation. Alternatively, using the Brinkman model for the porous media this difficulty does not occur. We review different interface conditions, including the well-known Beavers-Joseph-Saffman boundary condition and its recent improvement by Le Bars and Worster. (orig.)

  8. Photoelectrical stimulation of neuronal cells by an organic semiconductor-electrolyte Interface

    DEFF Research Database (Denmark)

    Abdullaeva, Oliya S.; Schulz, Matthias; Balzer, Frank

    2016-01-01

    As a step toward the realization of neuroprosthetics for vision restoration, we follow an electrophysiological patch-clamp approach to study the fundamental photoelectrical stimulation mechanism of neuronal model cells by an organic semiconductor–electrolyte interface. Our photoactive layer...... consisting of an anilino-squaraine donor blended with a fullerene acceptor is supporting the growth of the neuronal model cell line (N2A cells) without an adhesion layer on it and is not impairing cell viability. The transient photocurrent signal upon illumination from the semiconductor–electrolyte layer...... is able to trigger a passive response of the neuronal cells under physiological conditions via a capacitive coupling mechanism. We study the dynamics of the capacitive transmembrane currents by patch-clamp recordings and compare them to the dynamics of the photocurrent signal and its spectral responsivity...

  9. 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.

  10. 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

    . In this 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......A key role of signal transduction pathways is to control transcriptional programs in the nucleus as a function of signals received by the cell via complex post-translational modification cascades. This determines cell-context specific responses to environmental stimuli. Given the difficulty...... of quantitating protein concentration and post-translational modifications, signaling pathway studies are still for the most part conducted one interaction at the time. Thus, genome-wide, cell-context specific dissection of signaling pathways is still an open challenge in molecular systems biology...

  11. 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

    2016-05-17

    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/cm(2), 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/cm(2). 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.

  12. 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.

  13. 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.

  14. Simple way to engineer metal-semiconductor interface for enhanced performance of perovskite organic lead iodide solar cells.

    Science.gov (United States)

    Xu, Yuzhuan; Shi, Jiangjian; Lv, Songtao; Zhu, Lifeng; Dong, Juan; Wu, Huijue; Xiao, Yin; Luo, Yanhong; Wang, Shirong; Li, Dongmei; Li, Xianggao; Meng, Qingbo

    2014-04-23

    A thin wide band gap organic semiconductor N,N,N',N'-tetraphenyl-benzidine layer has been introduced by spin-coating to engineer the metal-semiconductor interface in the hole-conductor-free perovskite solar cells. The average cell power conversion efficiency (PCE) has been enhanced from 5.26% to 6.26% after the modification and a highest PCE of 6.71% has been achieved. By the aid of electrochemical impedance spectroscopy and dark current analysis, it is revealed that this modification can increase interfacial resistance of CH3NH3PbI3/Au interface and retard electron recombination process in the metal-semiconductor interface.

  15. The role of buffer/kesterite interface recombination and minority carrier lifetime on kesterite thin film solar cells

    Science.gov (United States)

    Courel, Maykel; Andrade-Arvizu, J. A.; Vigil-Galán, O.

    2016-09-01

    This paper presents for the first time a theoretical study of the impact of kesterite/buffer interface recombination and kesterite minority carrier lifetime on both CZTS and CZTSe solar cells. It demonstrates that only an 11% efficiency can be reached in CZTS solar cells by improving absorber crystalline quality, pointing out the need for an improved CdS/CZTS interface. It further demonstrates that a CZTS solar cell efficiency enhancement of up to 18%, with an open-circuit voltage value of up to 918 mV, can be achieved depending on CZTS minority carrier lifetime and CdS/CZTS interface recombination speed values. Moreover, this paper shows that by improving CZTSe crystalline quality, a record efficiency value of 17% could be achieved without focusing on improving CdS/CZTSe interface quality. Consequently, CZTSe is presented as a better candidate for solar cell applications. Conditions under which CdS/kesterite interface recombination and trap-assisted tunneling recombination become dominant are provided. In particular, we find that CdS/CZTS interface recombination is the dominant transport mechanism for CZTS minority carrier lifetime values higher than 5 ns, while for CZTSe minority carrier lifetime values lower than 0.1 μs, CdS/CZTSe interface losses are negligible.

  16. Organic solar cells: a rigorous model of the donor-acceptor interface for various bulk heterojunction morphologies

    Science.gov (United States)

    Raba, Adam; Leroy, Yann; Cordan, Anne-Sophie

    2014-02-01

    Theoretical studies of organic solar cells are mostly based on one dimensional models. Despite their accuracy to reproduce most of the experimental trends, they intrinsically cannot correctly integrate the effects of morphology in cells based on a bulk heterojunction structure. Therefore, accounting for these effects requires the development of two dimensional models, in which donor and acceptor domains are explicitly distinct. In this context, we propose an analytical approach, which focuses on the description of the interface between the two domains. Assuming pinned charge transfer states, we rigorously derive the corresponding boundary conditions and explore the differences between this model and other existing models in the literature for various morphologies of the active layer. On one hand, all tested models are equivalent for an ideal interdigitated bulk heterojunction solar cell with a planar donor-acceptor interface, but divergences between the models rise for small sizes of the donor domain. On the other hand, we carried out a comparison on a less ideal case of cell, with a rough interface between the two domains. Simulations with such cells exhibit distinct behaviors for each model. We conclude that the boundary condition for the interface between the materials is of great importance for the study of solar cells with a non-planar interface. The model must account initially for the roughness of the interface.

  17. Graphene-enhanced thermal interface materials for heat removal from photovoltaic solar cells

    Science.gov (United States)

    Saadah, M.; Gamalath, D.; Hernandez, E.; Balandin, A. A.

    2016-09-01

    The increase in the temperature of photovoltaic (PV) solar cells affects negatively their power conversion efficiency and decreases their lifetime. The negative effects are particularly pronounced in concentrator solar cells. Therefore, it is crucial to limit the PV cell temperature by effectively removing the excess heat. Conventional thermal phase change materials (PCMs) and thermal interface materials (TIMs) do not possess the thermal conductivity values sufficient for thermal management of the next generation of PV cells. In this paper, we report the results of investigation of the increased efficiency of PV cells with the use of graphene-enhanced TIMs. Graphene reveals the highest values of the intrinsic thermal conductivity. It was also shown that the thermal conductivity of composites can be increased via utilization of graphene fillers. We prepared TIMs with up to 6% of graphene designed specifically for PV cell application. The solar cells were tested using the solar simulation module. It was found that the drop in the output voltage of the solar panel under two-sun concentrated illumination can be reduced from 19% to 6% when grapheneenhanced TIMs are used. The proposed method can recover up to 75% of the power loss in solar cells.

  18. Profilin as a regulator of the membrane-actin cytoskeleton interface in plant cells

    Directory of Open Access Journals (Sweden)

    Tiantian eSun

    2013-12-01

    Full Text Available Membrane structures and cytoskeleton dynamics are intimately inter-connected in the eukaryotic cell. Recently, the molecular mechanisms operating at this interface have been progressively addressed. Many experiments have revealed that the actin cytoskeleton can interact with membranes through various discrete membrane domains. The actin-binding protein, profilin has been proven to inhibit actin polymerization and to promote F-actin elongation. This is dependent on many factors, such as the profilin/G-actin ratio and the ionic environment of the cell. Additionally, profilin has specific domains that interact with phosphoinositides and poly-L-proline rich proteins; theoretically, this gives profilin the opportunity to interact with membranes, and a large number of experiments have confirmed this possibility. In this article, we summarize recent findings in plant cells, and discuss the evidence of the connections among actin cytoskeleton, profilin and biomembranes through direct or indirect relationships.

  19. Hydrogen related phenomena at the ITO/a-Si:H/Si heterojunction solar cell interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ulyashin, Alexander [SINTEF Materials and Chemistry, Forskningsveien 1, P.O. Box 124, 0314 Oslo (Norway); Sytchkova, Anna [Optical Coatings Laboratory, ENEA Casaccia C.R.E., via Anguillarese 301, 00123 Rome (Italy)

    2013-04-15

    Properties of thin a-Si:H and indium-tin oxide (ITO) layers as well as properties of interfaces of Si based heterojunction (HJ) ITO/(p)a-Si:H/n-Si structures were analyzed by means of atomic force microscopy (AFM) and scanning spreading resistance microscopy. It is shown that the morphology of thin ITO layers grown on n-type polished crystalline Si or on (p)a-Si:H/n-Si substrates depends on the deposition temperature and has peculiarities on nano-scale. Formation of highly conductive nano-dots on the surface and in the bulk of ITO layers is found. The observed nano-spots and nano-dots are attributed to the influence of hydrogen initiated reduction process, which occurs upon deposition of ITO films on an a-Si:H layer during the fabrication process of a HJ solar cell. This fact is confirmed by investigation of morphological properties of ITO surfaces after treatment by hydrogen plasma. It is shown that formation of conductive nano-particles on the ITO surface initiated by hydrogen does not change essentially transparency of an ITO layer. It is concluded that conductive nano-dots at the ITO/a-Si:H interface can be considered as local conductive channels, which provide a current flow through the ITO/(p)a-Si:H interface without essential shadowing of the solar cell structure. This finding opens an interesting way for the optimization of properties of the ITO/Si-based HJ solar cells. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Interface control in organic heterojunction photovoltaic cells by phase separation processes

    Science.gov (United States)

    Heier, Jakob; Castro, Fernando A.; Nüesch, Frank; Hany, Roland

    2007-09-01

    Significant progress is being made in the photovoltaic energy conversion using organic semiconducting materials. One of the focuses of attention is the nanoscale morphology of the donor-acceptor mixture, to ensure efficient charge generation and loss-free charge transport at the same time. Using small molecule and polymer blend systems, recent efforts highlight the problems to ensure an optimized relationship between molecular structure, morphology and device properties. Here, we present two examples using a host/guest mixture approach for the controlled, sequential design of bilayer organic solar cell architectures that consist of a large interface area with connecting paths to the respective electrodes at the same time. In the first example, we employed polymer demixing during spin coating to produce a rough interface: surface directed spinodal decomposition leads to a 2-dimensional spinodal pattern with submicrometer features at the polymer-polymer interface. The second system consists of a solution of a blend of small molecules, where phase separation into a bilayer during spin coating is followed by dewetting. For both cases, the guest can be removed using a selective solvent after the phase separation process, and the rough host surface can be covered with a second active, semiconducting component. We explain the potential merits of the resulting interdigitated bilayer films, and explore to which extent polymer-polymer and surface interactions can be employed to create surface features in the nanometer range.

  1. FLOW CURVES OF AN ADSORBED PROTEIN LAYER AT THE SALIVA-AIR INTERFACE

    NARCIS (Netherlands)

    HOLTERMAN, HJ; SGRAVENMADE, EJ; WATERMAN, HA; BLOM, C; Mellema, J.

    1990-01-01

    At the air-liquid interface of human saliva a protein layer is absorbed. An apparatus is described with which a flow curve of this layer was measured. In the majority of samples the viscosity of the surface layer changed gradually and could be described by a power-law dependence on the shear rate. T

  2. 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...... as main interference mitigation technique. Both Interference Rejection Combining (IRC) and Successive Interference Cancellation (SIC) principles are considered. An efficient usage of such receivers is ensured by a proper frame structure design and system assumptions. Different approaches for the rank...

  3. 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

  4. In situ imaging of multiphase bio-interfaces at the micro-/nanoscale.

    Science.gov (United States)

    Chen, Peipei; Jiang, Lei; Han, Dong

    2011-10-17

    The multiphase bio-interfacial system constituted by biological surfaces and their surrounding environment is usually considered to be an essential clue for exploring the mysterious relationship between surface architecture and function. As a visualizing method to understand these systems, in situ imaging of multiphase interfaces (e.g., air/liquid/solid and oil/water/solid systems) at the micro-/nanoscale, still remains a huge challenge, as a result of their heterogeneity and complexity. Here, recent progress on real-space micro-/nanoscale imaging of multiphase bio-interfacial systems is reviewed; this includes several techniques and imaging results on bio-interfaces, such as the lotus leaf, fish scale, living cell's surface, and fresh tissue surface. The results evidently show that interfacial structures have a significant impact on the state of the microscopic multiphase interface, further influencing specific functions. Based on this research, technical innovations, some more complicated multiphase interface systems, and structure-function coupling mechanism are proposed.

  5. Dispersion of Particles on Fluid-Liquid Interfaces

    Science.gov (United States)

    Dalal, B.; Gurupatham, S.; Hossain, M.; Fischer, I.; Singh, P.; Joseph, D.

    2011-11-01

    This talk is concerned with the dispersion of particles on the fluid-liquid interface. In our previous studies we have shown that when small particles, e.g., flour, pollen, etc., come in contact with an air-liquid interface, they disperse in a manner that appears explosive. This is due to the fact that the capillary force pulls particles into the interface causing them to accelerate to a relatively-large velocity. The motion of particles in the direction normal to the interface is inertia dominated, and so they oscillate vertically about the equilibrium position before coming to a stop under viscous drag. This causes a radially-outward lateral flow on the interface that causes nearby particles to move away. In experiments the strength of the lateral flow was measured using tracer particles that were placed on the interface for this purpose. The dispersion on a liquid-liquid interface was relatively weaker than on an air-liquid interface, and occurred over a longer period of time. This partly was a consequence of the fact that particles became separated while sedimenting through the upper liquid and reached the interface over a time interval that lasted for several seconds. The rate of dispersion depended on the size of particles, the particle and liquids densities, the viscosities of the liquids involved, and the contact angle.

  6. 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.

  7. 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.

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

    Science.gov (United States)

    Harris, D Calvin; Jewett, Michael C

    2012-10-01

    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 for synthetic chemistry and using synthetic chemistry to reprogram or mimic biology. In the coming years, the impact of advances inspired by these approaches will make possible the synthesis of nonbiological polymers having new backbone compositions, new chemical properties, new structures, and new functions.

  9. Investigation of engineered bacterial adhesins for opportunity to interface cells with abiotic materials

    Science.gov (United States)

    Terrell, Jessica L.; Dong, Hong; Holthoff, Ellen L.; Small, Meagan C.; Sarkes, Deborah A.; Hurley, Margaret M.; Stratis-Cullum, Dimitra N.

    2016-05-01

    The convenience of cellular genetic engineering has afforded the power to build `smart' synthetic biological tools with novel applications. Here, we have explored opportunities to hybridize engineered cells with inorganic materials toward the development of 'living' device-compatible systems. Cellular structural biology is engineerable based on the ability to rewrite genetic code to generate recombinant, foreign, or even unnatural proteins. With this capability on the biological end, it should be possible to achieve superior abio-compatibility with the inorganic materials that compose current microfabricated technology. This work investigated the hair-like appendages of Escherichia coli known as Type 1 fimbriae that enable natural adhesion to glycosylated substrates. Sequence alterations within the fimbrial gene cluster were found to be well-tolerated, evidenced by tagging the fimbriae with peptide-based probes. As a further development, fimbriae tips could be reconfigured to, in turn, alter cell binding. In particular, the fimbriae were fused with a genetically optimized peptide-for-inorganics to enable metal binding. This work established methodologies to systematically survey cell adhesion properties across a suite of fimbriae-modified cell types as well as to direct patterned cell adhesion. Cell types were further customized for added complexity including turning on secondary gene expression and binding to gold surfaces. The former demonstrates potential for programmable gene switches and the latter for interfacing biology with inorganic materials. In general, the incorporation of 'programmed' cells into devices can be used to provide the feature of dynamic and automated cell response. The outcomes of this study are foundational toward the critical feature of deliberate positioning of cells as configurable biocomponentry. Overall, cellular integration into bioMEMs will yield advanced sensing and actuation.

  10. 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.

  11. The effects of the band bending caused by interface states in CdTe and CIS solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youn-Jung; Gray, J.L. [Purdue Univ., Lafayette, IN (United States). School of Electrical Engineering

    1994-12-31

    In this paper, the effects of interface states in the Z-nO/CdS/CuinSe{sub 2}, and CdS/CdTe solar cells are presented. The effects are investigated through numerical modeling using ADEPT (A Device Emulation Program and Tool). The results show that donor-like interface states have very little effect but acceptor-like interface states at the resistive ZnO/CdS can cause pinning of the bands at the interface, thus leading to non-exponential illuminated I-V curves when the interface state densities are high enough. High density of acceptor-like states between the CdS and In-rich CIS does not result in the two-diode like IV curves. Instead they can significantly lower the fill factor. In the CdS/CdTe solar cells. either donor- or acceptor-like interface states have little effect since almost all the depletion region lies in the CdTe. Thus, the metallurgical junction where the interface states are located is away from the electrical junction where the conductivity type changes.

  12. 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.

  13. Development of human nervous tissue upon differentiation of embryonic stem cells in three-dimensional culture.

    Science.gov (United States)

    Preynat-Seauve, Olivier; Suter, David M; Tirefort, Diderik; Turchi, Laurent; Virolle, Thierry; Chneiweiss, Herve; Foti, Michelangelo; Lobrinus, Johannes-Alexander; Stoppini, Luc; Feki, Anis; Dubois-Dauphin, Michel; Krause, Karl Heinz

    2009-03-01

    Researches on neural differentiation using embryonic stem cells (ESC) require analysis of neurogenesis in conditions mimicking physiological cellular interactions as closely as possible. In this study, we report an air-liquid interface-based culture of human ESC. This culture system allows three-dimensional cell expansion and neural differentiation in the absence of added growth factors. Over a 3-month period, a macroscopically visible, compact tissue developed. Histological coloration revealed a dense neural-like neural tissue including immature tubular structures. Electron microscopy, immunochemistry, and electrophysiological recordings demonstrated a dense network of neurons, astrocytes, and oligodendrocytes able to propagate signals. Within this tissue, tubular structures were niches of cells resembling germinal layers of human fetal brain. Indeed, the tissue contained abundant proliferating cells expressing markers of neural progenitors. Finally, the capacity to generate neural tissues on air-liquid interface differed for different ESC lines, confirming variations of their neurogenic potential. In conclusion, this study demonstrates in vitro engineering of a human neural-like tissue with an organization that bears resemblance to early developing brain. As opposed to previously described methods, this differentiation (a) allows three-dimensional organization, (b) yields dense interconnected neural tissue with structurally and functionally distinct areas, and (c) is spontaneously guided by endogenous developmental cues.

  14. 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.

  15. Architecture of the Interface between the Perovskite and Hole-Transport Layers in Perovskite Solar Cells.

    Science.gov (United States)

    Moriya, Masahiro; Hirotani, Daisuke; Ohta, Tsuyoshi; Ogomi, Yuhei; Shen, Qing; Ripolles, Teresa S; Yoshino, Kenji; Toyoda, Taro; Minemoto, Takashi; Hayase, Shuzi

    2016-09-22

    The interface between the perovskite (PVK, CH3 NH3 PbI3 ) and hole-transport layers in perovskite solar cells is discussed. The device architecture studied is as follows: F-doped tin oxide (FTO)-coated glass/compact TiO2 /mesoporous TiO2 /PVK/2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-MeOTAD)/Au. After a thin layer of 4,4,4-trifluorobutylammonium iodide (TFBA) was inserted at the interface between PVK and Spiro-MeOTAD, the photovoltaic efficiency increased from 11.6-14.5 % to 15.1-17.6 %. TFBA (10 ppm) was added in the PVK solution before coating. Owing to the low surface tension of TFBA, TFBA rose to the surface of the PVK layer spontaneously during spin-coating to make a thin organic layer. The PVK grain boundaries also seemed to be passivated with the addition of TFBA. However, large differences in Urbach energies and valence band energy level were not observed for the PVK layer with and without the addition of TFBA. The charge recombination time constant between the PVK and the Spiro-MeOTAD became slower (from 8.4 to 280 μsec) after 10 ppm of TFBA was added in the PVK. The experimental results using TFBA conclude that insertion of a very thin layer at the interface between PVK and Spiro-MeOTAD is effective for suppressing charge recombination and increasing photovoltaic performances.

  16. The origin of the eukaryotic cell based on conservation of existing interfaces.

    Science.gov (United States)

    de Roos, Albert D G

    2006-01-01

    Current theories about the origin of the eukaryotic cell all assume that during evolution a prokaryotic cell acquired a nucleus. Here, it is shown that a scenario in which the nucleus acquired a plasma membrane is inherently less complex because existing interfaces remain intact during evolution. Using this scenario, the evolution to the first eukaryotic cell can be modeled in three steps, based on the self-assembly of cellular membranes by lipid-protein interactions. First, the inclusion of chromosomes in a nuclear membrane is mediated by interactions between laminar proteins and lipid vesicles. Second, the formation of a primitive endoplasmic reticulum, or exomembrane, is induced by the expression of intrinsic membrane proteins. Third, a plasma membrane is formed by fusion of exomembrane vesicles on the cytoskeletal protein scaffold. All three self-assembly processes occur both in vivo and in vitro. This new model provides a gradual Darwinistic evolutionary model of the origins of the eukaryotic cell and suggests an inherent ability of an ancestral, primitive genome to induce its own inclusion in a membrane.

  17. 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

  18. Air–liquid interface enhances oxidative phosphorylation in intestinal epithelial cell line IPEC-J2

    Science.gov (United States)

    Klasvogt, Sonja; Zuschratter, Werner; Schmidt, Anke; Kröber, Andrea; Vorwerk, Sandra; Wolter, Romina; Isermann, Berend; Wimmers, Klaus; Rothkötter, Hermann-Josef; Nossol, Constanze

    2017-01-01

    The intestinal porcine epithelial cell line IPEC-J2, cultured under the air–liquid interface (ALI) conditions, develops remarkable morphological characteristics close to intestinal epithelial cells in vivo. Improved oxygen availability has been hypothesised to be the leading cause of this morphological differentiation. We assessed oxygen availability in ALI cultures and examined the influence of this cell culture method on glycolysis and oxidative phosphorylation in IPEC-J2 using the submerged membrane culture (SMC) and ALI cultures. Furthermore, the role of HIF-1 as mediator of oxygen availability was analysed. Measurements of oxygen tension confirmed increased oxygen availability at the medium–cell interface and demonstrated reduced oxygen extraction at the basal compartment in ALI. Microarray analysis to determine changes in the genetic profile of IPEC-J2 in ALI identified 2751 modified transcripts. Further examinations of candidate genes revealed reduced levels of glycolytic enzymes hexokinase II and GAPDH, as well as lactate transporting monocarboxylate transporter 1 in ALI, whereas expression of the glucose transporter GLUT1 remained unchanged. Cytochrome c oxidase (COX) subunit 5B protein analysis was increased in ALI, although mRNA level remained at constant level. COX activity was assessed using photometric quantification and a three-fold increase was found in ALI. Quantification of glucose and lactate concentrations in cell culture medium revealed significantly reduced glucose levels and decreased lactate production in ALI. In order to evaluate energy metabolism, we measured cellular adenosine triphosphate (ATP) aggregation in homogenised cell suspensions showing similar levels. However, application of the uncoupling agent FCCP reduced ATP levels in ALI but not in SMC. In addition, HIF showed reduced mRNA levels in ALI. Furthermore, HIF-1α protein was reduced in the nuclear compartment of ALI when compared to SCM as confirmed by confocal microscopy

  19. 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.

  20. Interfacing polymeric scaffolds with primary pancreatic ductal adenocarcinoma cells to develop 3D cancer models.

    Science.gov (United States)

    Ricci, Claudio; Mota, Carlos; Moscato, Stefania; D'Alessandro, Delfo; Ugel, Stefano; Sartoris, Silvia; Bronte, Vincenzo; Boggi, Ugo; Campani, Daniela; Funel, Niccola; Moroni, Lorenzo; Danti, Serena

    2014-01-01

    We analyzed the interactions between human primary cells from pancreatic ductal adenocarcinoma (PDAC) and polymeric scaffolds to develop 3D cancer models useful for mimicking the biology of this tumor. Three scaffold types based on two biocompatible polymeric formulations, such as poly(vinyl alcohol)/gelatin (PVA/G) mixture and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymer, were obtained via different techniques, namely, emulsion and freeze-drying, compression molding followed by salt leaching, and electrospinning. In this way, primary PDAC cells interfaced with different pore topographies, such as sponge-like pores of different shape and size or nanofiber interspaces. The aim of this study was to investigate the influence played by the scaffold architecture over cancerous cell growth and function. In all scaffolds, primary PDAC cells showed good viability and synthesized tumor-specific metalloproteinases (MMPs) such as MMP-2, and MMP-9. However, only sponge-like pores, obtained via emulsion-based and salt leaching-based techniques allowed for an organized cellular aggregation very similar to the native PDAC morphological structure. Differently, these cell clusters were not observed on PEOT/PBT electrospun scaffolds. MMP-2 and MMP-9, as active enzymes, resulted to be increased in PVA/G and PEOT/PBT sponges, respectively. These findings suggested that spongy scaffolds supported the generation of pancreatic tumor models with enhanced aggressiveness. In conclusion, primary PDAC cells showed diverse behaviors while interacting with different scaffold types that can be potentially exploited to create stage-specific pancreatic cancer models likely to provide new knowledge on the modulation and drug susceptibility of MMPs.

  1. Interface Engineering of Metal Oxides using Ammonium Anthracene in Inverted Organic Solar Cells.

    Science.gov (United States)

    Jeon, Il; Zeljkovic, Sasa; Kondo, Kei; Yoshizawa, Michito; Matsuo, Yutaka

    2016-11-09

    In this work, by casting water-soluble ammonium anthracene on metal oxides, the organic surface modifier re-engineered the interface of the metal oxide to improve charge transport. The energy level of ammonium anthracene increased the work function of indium tin oxide (ITO), functioning as a hole-blocker (electron-transporter). Solar cells in which ITO was treated by the ammonium anthracene produced an average power conversion efficiency (PCE) of 5.8% without ZnO, the electron-transporting layer. When the ammonium anthracene was applied to ZnO, an average PCE of 8.1% was achieved, which is higher than the average PCE of 7.5% for nontreated ZnO-based devices.

  2. 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.

  3. Characterization of Organic Solar Cell Devices and their Interfaces under Degradation: Imaging, Electrical and Mechanical Methods

    DEFF Research Database (Denmark)

    Corazza, Michael

    techniques were also employed in order to study the effect of degradation on the device structure and its interfaces. This was done by exploiting different techniques that measured different properties of the device: mechanical, imaging, and electrical. Mechanical characterization of roll-to-roll processed....... Finally, imaging of cross sections of an ITO-free roll-to-roll processed device was performed successfully using transmission electron microscopy. The cross sections were prepared both with focused-ion-beam and ultramicrotomy, which gave the possibility for effectively comparing these two techniques...... energy is one of the answers for renewable energy. In this thesis, the research has been conducted on polymer solar cells. In particular, the thesis deals with the extensive study of device lifetime, characterized with several methods: from bare benchmarking of the lifetimes, to more advanced...

  4. Surface and interface properties of Zn3P2 solar cells

    Science.gov (United States)

    Kazmerski, L. L.; Ireland, P. J.; Catalano, A.

    1981-03-01

    The compositional properties of Zn3P2 thin films are studied using surface analysis techniques. Relative sensitivity factors of S(Zn sub LMM) = 0.29 and S(P sub LMM) = 0.34 are determined for this semiconductor with the aid of Auger electron spectroscopy standard spectra. The interfacial properties of the Mg/Zn3P2 thin-film solar cell are studied using Auger electron spectroscopy depth-compositional profiling in conjunction with complementary secondary ion mass spectroscopy and X-ray photoelectron spectroscopy data. Evidence is adduced for the formation of Mg3P2 at the metal-semiconductor interface. It is noted that this compound has a bandgap near that of Zn3P2. Attention is given to the possible formation of a heterojunction as a result of the interfacial reaction.

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

    Energy Technology Data Exchange (ETDEWEB)

    Theisen, J.P.; Erfurth, F.; Weinhardt, L. [University of Wuerzburg (Germany). Experimental Physics VII; Duarte, R.; Baer, M. [Helmholtz Institut, Berlin (Germany); Niesen, T.; Palm, J. [Avancis GmbH, Muenchen (Germany); Barreau, N.; Couzinie-Devy, F.; Kessler, J. [Institut des Materiaux, Nantes (France); Reinert, F. [University of Wuerzburg (Germany). Experimental Physics VII; Forschungszentrum Karlsruhe GmbH (Germany). Gemeinschaftslabor fuer Nanoanalytik

    2010-07-01

    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){sub 2} (CIGSSe) is of great interest. Alternative buffer layers like (In,Al){sub 2}S{sub 3}, In{sub 2}S{sub 3}, or (Zn{sub 1-x},Mg{sub x})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.

  6. Electronic Interfacing Between a Living Cell and a Nanodevice: A Bio-Nano Hybrid System

    Energy Technology Data Exchange (ETDEWEB)

    Saraf, Ravi F. [Univ. of Nebraska, Lincoln, NE (United States). Dept. of Chemical and Biomolecular Engineering

    2013-12-31

    The primary goal of this program was to couple physical electronics with live cells to leverage the highly sophisticated functions of a biological system to ultimately create advanced functionality. The study was built on a unique self-assembled architecture of nanoparticles that exhibits transport properties that are sensitive to single-electron charge modulation. At room temperature, the energy of switching due to single-electron charge modulation was in the range of 4 to 100 kT. The structure invented in the principal investigator’s lab is a two-dimensional (2D) network of one-dimensional (1D) necklaces of 10 nm Au nanoparticles. The electron transport through the necklace network is regulated by quantum mechanical single-electron traps. As a result of the single electron traps, the all metal nanoparticle network array displays a conduction band gap. Fundamental studies on the transport properties of the network in air and water were studied to regulate the band gap by tailoring the network structure to demonstrate the first electrochemical single electron transistor operating in water. Cells were interfaced with the network to observe electrochemical activity in a cell during photosynthesis and single viral infection.

  7. 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.

  8. High-Efficiency Silicon/Organic Heterojunction Solar Cells with Improved Junction Quality and Interface Passivation.

    Science.gov (United States)

    He, Jian; Gao, Pingqi; Ling, Zhaoheng; Ding, Li; Yang, Zhenhai; Ye, Jichun; Cui, Yi

    2016-12-27

    Silicon/organic heterojunction solar cells (HSCs) based on conjugated polymers, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and n-type silicon (n-Si) have attracted wide attention due to their potential advantages of high efficiency and low cost. However, the state-of-the-art efficiencies are still far from satisfactory due to the inferior junction quality. Here, facile treatments were applied by pretreating the n-Si wafer in tetramethylammonium hydroxide (TMAH) solution and using a capping copper iodide (CuI) layer on the PEDOT:PSS layer to achieve a high-quality Schottky junction. Detailed photoelectric characteristics indicated that the surface recombination was greatly suppressed after TMAH pretreatment, which increased the thickness of the interfacial oxide layer. Furthermore, the CuI capping layer induced a strong inversion layer near the n-Si surface, resulting in an excellent field effect passivation. With the collaborative improvements in the interface chemical and electrical passivation, a competitive open-circuit voltage of 0.656 V and a high fill factor of 78.1% were achieved, leading to a stable efficiency of over 14.3% for the planar n-Si/PEDOT:PSS HSCs. Our findings suggest promising strategies to further exploit the full voltage as well as efficiency potentials for Si/organic solar cells.

  9. 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.

  10. Critical interfaces in organic solar cells and their influence on the open-circuit voltage.

    Science.gov (United States)

    Potscavage, William J; Sharma, Asha; Kippelen, Bernard

    2009-11-17

    Organic photovoltaics, which convert sunlight into electricity with thin films of organic semiconductors, have been the subject of active research over the past 20 years. The global energy challenge has greatly increased interest in this technology in recent years. Low-temperature processing of organic small molecules from the vapor phase or of polymers from solution can confer organic semiconductors with a critical advantage over inorganic photovoltaic materials since the high-temperature processing requirements of the latter limit the range of substrates on which they can be deposited. Unfortunately, despite significant advances, the power conversion efficiency of organic solar cells remains low, with maximum values in the range of 6%. A better understanding of the physical processes that determine the efficiency of organic photovoltaic cells is crucial to enhancing their competitiveness with other thin-film technologies. Maximum values for the photocurrent can be estimated from the light-harvesting capability of the individual molecules or polymers in the device. However, a better understanding of the materials-level processes, particularly those in layer-to-layer interfaces, that determine the open-circuit voltage (V(OC)) in organic solar cells is critical and remains the subject of active research. The conventional wisdom is to use organic semiconductors with smaller band gaps to harvest a larger portion of the solar spectrum. This method is not always an effective prescription for increasing efficiency: it ignores the fact that the value of V(OC) is generally decreased in devices employing materials with smaller band gaps, as is the case with inorganic semiconductors. In this Account, we discuss the influence of the different interfaces formed in organic multilayer photovoltaic devices on the value of V(OC); we use pentacene-C(60) solar cells as a model. In particular, we use top and bottom electrodes with different work function values, finding that V(OC) is

  11. Polarization Force Microscopy of the Cell-Mineral Interface: Insights Into the Bioelectric Signature

    Science.gov (United States)

    Bartosik, E. M.; Kendall, T. A.

    2007-12-01

    The success of bioremediation strategies is dependent upon effective monitoring of microorganisms in the subsurface. Induced polarization (IP) may represent a cost-effective, complementary technique to existing borehole-based microbe detection schemes. Recent studies show a significant, yet poorly understood IP effect associated with the presence of bacteria in aqueous and porous media. This effect is believed to be rooted in the physicochemical surface interactions between cells and minerals which we probe using polarization and electric force microscopy. Dispersions of the local permittivity inferred from polarization force data that was collected over a hydrated mineral surface correspond to dispersions modeled for a bacterium. In each case, absolute permittivities and frequency cut-off values increase with surface potential and ion mobility, respectively. Potentially similar polarization mechanisms between the inorganic and organic condition are inferred. Further polarization force microscopy measurements of the mineral-microbe interface will provide molecular-level insight that complements column and field-scale IP observations. Anticipated is a more comprehensive mechanisitic description of the bioelectric IP response that facilitates application of IP to bioremediation.

  12. Engineering the cell-semiconductor interface: a materials modification approach using II-VI and III-V semiconductor materials.

    Science.gov (United States)

    Bain, Lauren E; Ivanisevic, Albena

    2015-02-18

    Developing functional biomedical devices based on semiconductor materials requires an understanding of interactions taking place at the material-biosystem interface. Cell behavior is dependent on the local physicochemical environment. While standard routes of material preparation involve chemical functionalization of the active surface, this review emphasizes both biocompatibility of unmodified surfaces as well as use of topographic features in manipulating cell-material interactions. Initially, the review discusses experiments involving unmodified II-VI and III-V semiconductors - a starting point for assessing cytotoxicity and biocompatibility - followed by specific surface modification, including the generation of submicron roughness or the potential effect of quantum dot structures. Finally, the discussion turns to more recent work in coupling topography and specific chemistry, enhancing the tunability of the cell-semiconductor interface. With this broadened materials approach, researchers' ability to tune the interactions between semiconductors and biological environments continues to improve, reaching new heights in device function.

  13. Anomalous system-size dependence of electrolytic cells with an electrified oil-water interface

    NARCIS (Netherlands)

    Westbroek, Marise; Boon, Niels; van Roij, Rene

    2015-01-01

    Manipulation of the charge of the dielectric interface between two bulk liquids not only enables the adjustment of the interfacial tension but also controls the storage capacity of ions in the ionic double layers adjacent to each side of the interface. However, adjusting this interfacial charge by s

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Sathyanarayana, E-mail: asharao76@gmail.com; Rao, Asha, E-mail: asharao76@gmail.com [Department of Physics, Mangalore Institute of Technology and Engineering, Moodabidri, Mangalore-574225 (India); Krishnan, Sheeja [Department of Physics, Sri Devi Institute of Technology, Kenjar, Mangalore-574142 (India); Sanjeev, Ganesh [Microtron Centre, Department of Physics, Mangalore University, Mangalagangothri-574199 (India); Suresh, E. P. [Solar Panel Division, ISRO Satellite Centre, Bangalore-560017 (India)

    2014-04-24

    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.

  16. Energy level alignment in TiO2/metal sulfide/polymer interfaces for solar cell applications.

    Science.gov (United States)

    Lindblad, Rebecka; Cappel, Ute B; O'Mahony, Flannan T F; Siegbahn, Hans; Johansson, Erik M J; Haque, Saif A; Rensmo, Håkan

    2014-08-28

    Semiconductor sensitized solar cell interfaces have been studied with photoelectron spectroscopy to understand the interfacial electronic structures. In particular, the experimental energy level alignment has been determined for complete TiO2/metal sulfide/polymer interfaces. For the metal sulfides CdS, Sb2S3 and Bi2S3 deposited from single source metal xanthate precursors, it was shown that both driving forces for electron injection into TiO2 and hole transfer to the polymer decrease for narrower bandgaps. The energy level alignment results were used in the discussion of the function of solar cells with the same metal sulfides as light absorbers. For example Sb2S3 showed the most favourable energy level alignment with 0.3 eV driving force for electron injection and 0.4 eV driving force for hole transfer and also the most efficient solar cells due to high photocurrent generation. The energy level alignment of the TiO2/Bi2S3 interface on the other hand showed no driving force for electron injection to TiO2, and the performance of the corresponding solar cell was very low.

  17. 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...... be involved, describe the evolution of these interface structures and finally explore the new chemistries that allow control and manipulation of these architectures to optimize both performance and durability....

  18. Anomalous system-size dependence of electrolytic cells with an electrified oil-water interface.

    Science.gov (United States)

    Westbroek, Marise; Boon, Niels; van Roij, René

    2015-10-14

    Manipulation of the charge of the dielectric interface between two bulk liquids not only enables the adjustment of the interfacial tension but also controls the storage capacity of ions in the ionic double layers adjacent to each side of the interface. However, adjusting this interfacial charge by static external electric fields is difficult since the external electric fields are readily screened by ionic double layers that form in the vicinity of the external electrodes. This leaves the liquid-liquid interface, which is at a macroscopic distance from the electrodes, unaffected. In this study we show theoretically, in agreement with recent experiments, that control over this surface charge at the liquid-liquid interface is nonetheless possible for macroscopically large but finite closed systems in equilibrium, even when the distance between the electrode and interface is orders of magnitude larger than the Debye screening lengths of the two liquids. We identify a crossover system-size below which the interface and the electrodes are effectively coupled. Our calculations of the interfacial tension for various electrode potentials are in good agreement with recent experimental data.

  19. SuperSILAC Quantitative Proteome Profiling of Murine Middle Ear Epithelial Cell Remodeling with NTHi.

    Directory of Open Access Journals (Sweden)

    Stéphanie Val

    Full Text Available Chronic Otitis Media with effusion (COME develops after sustained inflammation and is characterized by secretory middle ear epithelial metaplasia and effusion, most frequently mucoid. Non-typeable Haemophilus influenzae (NTHi, the most common acute Otitis Media (OM pathogen, is postulated to promote middle ear epithelial remodeling in the progression of OM from acute to chronic. The goals of this study were to examine histopathological and quantitative proteomic epithelial effects of NTHi challenge in a murine middle ear epithelial cell line.NTHi lysates were generated and used to stimulate murine epithelial cells (mMEEC cultured at air-liquid interface over 48 hours- 1 week. Conditional quantitative Stable Isotope Labeling with Amino Acids in Cell Culture (SILAC of cell lysates was performed to interrogate the global protein production in the cells, using the SuperSILAC technique. Histology of the epithelium over time was done to measure bacterial dependent remodeling.Mass spectrometry analysis identified 2,565 proteins across samples, of which 74 exhibited differential enrichment or depletion in cell lysates (+/-2.0 fold-change; p value<0.05. The key molecular functions regulated by NTHi lysates exposure were related to cell proliferation, death, migration, adhesion and inflammation. Finally, chronic exposure induced significant epithelial thickening of cells grown at air liquid interface.NTHi lysates drive pathways responsible of cell remodeling in murine middle ear epithelium which likely contributes to observed epithelial hyperplasia in vitro. Further elucidation of these mediators will be critical in understanding the progression of OM from acute to chronic at the molecular level.

  20. 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

    2016-07-12

    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.

  1. 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.

  2. Fabrication of CuInS2-sensitized solar cells via an improved SILAR process and its interface electron recombination.

    Science.gov (United States)

    Xu, Xueqing; Wan, Qingcui; Luan, Chunyan; Mei, Fengjiao; Zhao, Qian; An, Ping; Liang, Zhurong; Xu, Gang; Zapien, Juan Antonio

    2013-11-13

    Tetragonal CuInS2 (CIS) has been successfully deposited onto mesoporous TiO2 films by in-sequence growth of InxS and CuyS via a successive ionic layer absorption and reaction (SILAR) process and postdeposition annealing in sulfur ambiance. X-ray diffraction and Raman measurements showed that the obtained tetragonal CIS consisted of a chalcopyrite phase and Cu-Au ordering, which related with the antisite defect states. For a fixed Cu-S deposition cycle, an interface layer of β-In2S3 formed at the TiO2/CIS interface with suitable excess deposition of In-S. In the meantime, the content of the Cu-Au ordering phase decreased to a reasonable level. These facts resulted in the retardance of electron recombination in the cells, which is proposed to be dominated by electron transfer from the conduction band of TiO2 to the unoccupied defect states in CIS via exponentially distributed surface states. As a result, a relatively high efficiency of ~0.92% (V(oc) = 0.35 V, J(sc) = 8.49 mA cm(-2), and FF = 0.31) has been obtained. Last, but not least, with an overloading of the sensitizers, a decrease in the interface area between the sensitized TiO2 and electrolytes resulted in deceleration of hole extraction from CIS to the electrolytes, leading to a decrease in the fill factor of the solar cells. It is indicated that the unoccupied states in CIS with energy levels below EF0 of the TiO2 films play an important role in the interface electron recombination at low potentials and has a great influence on the fill factor of the solar cells.

  3. Finite Bias Calculations to Model Interface Dipoles in Electrochemical Cells at the Atomic Scale

    DEFF Research Database (Denmark)

    Hansen, Martin Hangaard; Jin, Chengjun; Thygesen, Kristian Sommer

    2016-01-01

    The structure of an electrochemical interface is not determined by any external electrostatic field, but rather by external chemical potentials. This paper demonstrates that the electric double layer should be understood fundamentally as an internal electric field set up by the atomic structure t...... to satisfy the thermodynamic constraints imposed by the environment. This is captured by the generalized computational hydrogen electrode model, which enables us to make efficient first-principles calculations of atomic scale properties of the electrochemical interface.......The structure of an electrochemical interface is not determined by any external electrostatic field, but rather by external chemical potentials. This paper demonstrates that the electric double layer should be understood fundamentally as an internal electric field set up by the atomic structure...

  4. 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.

  5. Self-assembly of microscopic chiplets at a liquid-liquid-solid interface forming a flexible segmented monocrystalline solar cell.

    Science.gov (United States)

    Knuesel, Robert J; Jacobs, Heiko O

    2010-01-19

    This paper introduces a method for self-assembling and electrically connecting small (20-60 micrometer) semiconductor chiplets at predetermined locations on flexible substrates with high speed (62500 chips/45 s), accuracy (0.9 micrometer, 0.14 degrees), and yield (> 98%). The process takes place at the triple interface between silicone oil, water, and a penetrating solder-patterned substrate. The assembly is driven by a stepwise reduction of interfacial free energy where chips are first collected and preoriented at an oil-water interface before they assemble on a solder-patterned substrate that is pulled through the interface. Patterned transfer occurs in a progressing linear front as the liquid layers recede. The process eliminates the dependency on gravity and sedimentation of prior methods, thereby extending the minimal chip size to the sub-100 micrometer scale. It provides a new route for the field of printable electronics to enable the integration of microscopic high performance inorganic semiconductors on foreign substrates with the freedom to choose target location, pitch, and integration density. As an example we demonstrate a fault-tolerant segmented flexible monocrystalline silicon solar cell, reducing the amount of Si that is used when compared to conventional rigid cells.

  6. A macroscopic model of proton transport through the membrane-ionomer interface of a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Kumar, Milan; Edwards, Brian J.; Paddison, Stephen J.

    2013-02-01

    The membrane-ionomer interface is the critical interlink of the electrodes and catalyst to the polymer electrolyte membrane (PEM); together forming the membrane electrode assembly in current state-of-the-art PEM fuel cells. In this paper, proton conduction through the interface is investigated to understand its effect on the performance of a PEM fuel cell. The water containing domains at this interface were modeled as cylindrical pores/channels with the anionic groups (i.e., -SO3-) assumed to be fixed on the pore wall. The interactions of each species with all other species and an applied external field were examined. Molecular-based interaction potential energies were computed in a small test element of the pore and were scaled up in terms of macroscopic variables. Evolution equations of the density and momentum of the species (water molecules and hydronium ions) were derived within a framework of nonequilibrium thermodynamics. The resulting evolution equations for the species were solved analytically using an order-of-magnitude analysis to obtain an expression for the proton conductivity. Results show that the conductivity increases with increasing water content and pore radius, and strongly depends on the separation distance between the sulfonate groups and their distribution on the pore wall. It was also determined that the conductivity of two similar pores of different radii in series is limited by the pore with the smaller radius.

  7. Simulation of compressible two-phase flows with topology change of fluid-fluid interface by a robust cut-cell method

    Science.gov (United States)

    Lin, Jian-Yu; Shen, Yi; Ding, Hang; Liu, Nan-Sheng; Lu, Xi-Yun

    2017-01-01

    We develop a robust cut-cell method for numerical simulation of compressible two-phase flows with topology change of the fluid-fluid interface. In cut cell methods the flows can be solved in the finite volume framework and the jump conditions at the interface are resolved by solving a local Riemann problem. Therefore, cut cell methods can obtain interface evolution with high resolution, and at the same time satisfactorily maintain the conservation of flow quantities. However, it remains a challenge for the cut cell methods to handle interfaces with topology change or very high curvature, where the mesh is not sufficiently fine to resolve the interface. Inappropriate treatment could give rise to either distorted interface advection or unphysical oscillation of flow variables, especially when the regularization process (e.g. reinitialization in the level set methods) is implemented. A robust cut-cell method is proposed here, with the interface being tracked by a level set function. The local unphysical oscillation of flow variables in the presence of topology change is shown to be greatly suppressed by using a delayed reinitialization. The method can achieve second-order accuracy with respect to the interface position in the absence of topology changes of interface, while locally degrading to first-order at the interface region where topology change occurs. Its performance is examined through a variety of numerical tests, such as Rayleigh collapse, shock-bubble interaction, and shock-induced bubble collapse in water. Numerical results are compared against either benchmark solutions or experimental observations, and good agreement has been achieved qualitatively and/or quantitatively. Finally, we apply the method to investigating the collapse process of two tandem bubbles in water.

  8. Innate immune response of human alveolar type II cells infected with severe acute respiratory syndrome-coronavirus.

    Science.gov (United States)

    Qian, Zhaohui; Travanty, Emily A; Oko, Lauren; Edeen, Karen; Berglund, Andrew; Wang, Jieru; Ito, Yoko; Holmes, Kathryn V; Mason, Robert J

    2013-06-01

    Severe acute respiratory syndrome (SARS)-coronavirus (CoV) produces a devastating primary viral pneumonia with diffuse alveolar damage and a marked increase in circulating cytokines. One of the major cell types to be infected is the alveolar type II cell. However, the innate immune response of primary human alveolar epithelial cells infected with SARS-CoV has not been defined. Our objectives included developing a culture system permissive for SARS-CoV infection in primary human type II cells and defining their innate immune response. Culturing primary human alveolar type II cells at an air-liquid interface (A/L) improved their differentiation and greatly increased their susceptibility to infection, allowing us to define their primary interferon and chemokine responses. Viral antigens were detected in the cytoplasm of infected type II cells, electron micrographs demonstrated secretory vesicles filled with virions, virus RNA concentrations increased with time, and infectious virions were released by exocytosis from the apical surface of polarized type II cells. A marked increase was evident in the mRNA concentrations of interferon-β and interferon-λ (IL-29) and in a large number of proinflammatory cytokines and chemokines. A surprising finding involved the variability of expression of angiotensin-converting enzyme-2, the SARS-CoV receptor, in type II cells from different donors. In conclusion, the cultivation of alveolar type II cells at an air-liquid interface provides primary cultures in which to study the pulmonary innate immune responses to infection with SARS-CoV, and to explore possible therapeutic approaches to modulating these innate immune responses.

  9. PRESERVATION OF THE CELL-BIOMATERIAL INTERFACE AT THE ULTRASTRUCTURAL LEVEL

    NARCIS (Netherlands)

    SCHAKENRAAD, JM; OOSTERBAAN, JA; BLAAUW, EH

    1991-01-01

    Studying the tissue-biomaterial interface at the ultrastructural level is not without problems. Dissolution of the biomaterial in one of the dehydration or embedding media causes holes and shatter during sectioning or dislodgement of the biomaterial. The fine tuning of the hardness of both biomateri

  10. Photoelectron spectroscopy and modeling of interface properties related to organic photovoltaic cells

    NARCIS (Netherlands)

    Fahlman, Mats; Sehati, Parisa; Osikowicz, Wojciech; Braun, Slawomir; Jong, de Michel P.; Brocks, Geert

    2013-01-01

    In this short review, we will give examples on how photoelectron spectroscopy (PES) assisted by models on interface energetics can be used to study properties important to bulk heterojunction type organic photovoltaic devices focusing on the well-known bulk heterojunction blend of poly(3-hexylthioph

  11. 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

  12. Characterization of the interface of the bone marrow stromal cell antigen 2-Vpu protein complex via computational chemistry.

    Science.gov (United States)

    Zhou, Jinming; Zhang, Zhixin; Mi, Zeyun; Wang, Xin; Zhang, Quan; Li, Xiaoyu; Liang, Chen; Cen, Shan

    2012-02-14

    Bone marrow stromal cell antigen 2 (BST-2) inhibits the release of enveloped viruses from the cell surface. Various viral counter measures have been discovered, which allow viruses to escape BST-2 restriction. Human immunodeficiency virus type 1 (HIV-1) encodes viral protein U (Vpu) that interacts with BST-2 through their transmembrane domains and causes the downregulation of cell surface BST-2. In this study, we used a computer modeling method to establish a molecular model to investigate the binding interface of the transmembrane domains of BST-2 and Vpu. The model predicts that the interface is composed of Vpu residues I6, A10, A14, A18, V25, and W22 and BST-2 residues L23, I26, V30, I34, V35, L41, I42, and T45. Introduction of mutations that have been previously reported to disrupt the Vpu-BST-2 interaction led to a calculated higher binding free energy (MMGBSA), which supports our molecular model. A pharmacophore was also generated on the basis of this model. Our results provide a precise model that predicts the detailed interaction occurring between the transmembrane domains of Vpu and BST-2 and should facilitate the design of anti-HIV agents that are able to disrupt this interaction.

  13. Progress and prospects in neurorehabilitation: clinical applications of stem cells and brain-computer interface for spinal cord lesions.

    Science.gov (United States)

    Gongora, Mariana; Peressutti, Caroline; Machado, Sergio; Teixeira, Silmar; Velasques, Bruna; Ribeiro, Pedro

    2013-04-01

    Spinal cord injury (SCI) is a disease that affects millions of people worldwide, causing a temporary or permanent impairment of neuromotor functions. Mostly associated to traumatic lesions, but also to other forms of disease, the appropriate treatment is still unsure. In this review, several ongoing studies are presented that aim to provide methods of prevention that ensure quality of life, and rehabilitation trends to patients who suffer from this injury. Stem cell research, highlighted in this review, seeks to reduce damage caused to the tissue, as also provide spinal cord regeneration through the application of several types of stem cells. On the other hand, research using brain-computer interface (BCI) technology proposes the development of interfaces based on the interaction of neural networks with artificial tools to restore motor control and full mobility of the injured area. PubMed, MEDLINE and SciELO data basis analyses were performed to identify studies published from 2000 to date, which describe the link between SCI with stem cells and BCI technology.

  14. Study of the CdS/CdTe interface and its relevance to solar cell properties

    Science.gov (United States)

    Dhere, Ramesh Gurupad

    CdTe based devices have shown significant progress over the last decade. CdS/CdTe devices fabricated by close-spaced sublimation have resulted in 15.8% efficiency. To understand the effect of CdS/CdTe interface properties on device properties, a detailed investigation of the dependence of properties of CdS, CdTe and CdS/CdTe interface on various processing parameters is reported. Analysis of CdS/CdTe devices fabricated under identical conditions, was carried out to determine any correlation between the interface properties and device characteristics. Possible mechanisms to explain the correlation are presented. The CdS layers were deposited by chemical bath deposition (CBD) on glass/SnOsb2 substrates. The CdTe layers were grown by close-spaced sublimation (CSS) on glass/SnOsb2/CdS substrates. Post-deposition CdClsb2 heat-treatment was carried out using different concentrations of CdClsb2/methanol solution. CBD CdS gives conformal coverage on rough SnOsb2 layers at a thickness as low as 30 nm. Under optimal conditions, CdS films with refractive index close to bulk index are obtained indicating that the layers are void-free. The grain-size of CBD CdS films is independent of film thickness and is established during the early part of growth. AFM analysis of CSS CdTe shows that the films are faceted for the entire temperature range (475sp°C-625sp°C) investigated, the grain-size increases with substrate temperature, and the films are free of voids. X-ray diffraction analysis reveals that CdTe films grown at substrate temperatures ≥525sp°C have preferred orientation and the orientation is not affected by the CdClsb2 heat-treatment, indicating that the films deposited at these temperatures are more compact. TEM analysis of CdS/CdTe structures suggests that the majority of structural defects in the CdTe layers are generated at the interface and are caused by lattice mismatch and growth conditions. Cathodoluminescence and photoluminescence analysis shows that CdClsb2

  15. Interfaces Select Specific Stereochemical Conformations: The Isomerization of Glyoxal at the Liquid Water Interface.

    Science.gov (United States)

    Zhu, Chongqin; Kais, Sabre; Zeng, Xiao Cheng; Francisco, Joseph S; Gladich, Ivan

    2017-01-11

    Interfacial chemistry involving glyoxal at aerosol surfaces is postulated to catalyze aerosol growth. This chemistry remains speculative due to a lack of detailed information concerning the physicochemical behavior of glyoxal at the interface of atmospheric aerosols. Here, we report results from high-level electronic structure calculations as well as both classical and Born-Oppenheimer ab initio molecular dynamics simulations of glyoxal solvation at the air/liquid water interface. When compared to the gas phase, the trans to cis isomerization of glyoxal at the liquid water interface is found to be catalyzed; additionally, the trans conformation is selectively solvated within the bulk to a greater degree than is the cis conformation. These two processes, i.e., the catalytic effect at the water interface and the differentially selective solvation, act to enhance the concentration of the cis isomer of glyoxal at the water interface. This has important consequences for the interpretation of experiments and for the modeling of glyoxal chemistry both at the interface of water clouds and at aerosols. Broader implications of this work relate to describing the role of interfaces in selecting specific stereo molecular structures at interfacial environments.

  16. Mammalian skin cell biology: at the interface between laboratory and clinic.

    Science.gov (United States)

    Watt, Fiona M

    2014-11-21

    Mammalian skin research represents the convergence of three complementary disciplines: cell biology, mouse genetics, and dermatology. The skin provides a paradigm for current research in cell adhesion, inflammation, and tissue stem cells. Here, I discuss recent insights into the cell biology of skin. Single-cell analysis has revealed that human epidermal stem cells are heterogeneous and differentiate in response to multiple extrinsic signals. Live-cell imaging, optogenetics, and cell ablation experiments show skin cells to be remarkably dynamic. High-throughput, genome-wide approaches have yielded unprecedented insights into the circuitry that controls epidermal stem cell fate. Last, integrative biological analysis of human skin disorders has revealed unexpected functions for elements of the skin that were previously considered purely structural.

  17. 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....

  18. 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

  19. Interface reactions in Mg/Zn3P2 solar cells

    Science.gov (United States)

    Kazmerski, L. L.; Ireland, P. J.; Catalano, A.

    1981-05-01

    The composition and chemistry of the Mg/Zn3P2 interface was studied using surface analysis techniques. For higher carrier concentrations (p 10 to the 17th power/cu cm), a heterojunction occurs by the chemical interaction of the Mg with Zn3P2 to form Mg3P2. For lower carrier concentrations this reaction does not take place, and Mg diffuses into the Zn3P2. Diffusion coefficients of Mg in Zn3P2 are determined. Grain (crystalline) and grain boundary components of the diffusion coefficient are evaluated. These data compare very well with that reported using electron beam induced currents and spectral response measurements.

  20. 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.

  1. 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)

  2. 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

    2016-08-01

    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.

  3. 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

  4. Formation of the physical vapor deposited CdS Cu In,Ga Se2 interface in highly efficient thin film solar cells

    OpenAIRE

    Rusu, M.; Glatzel, Th.; Neisser, A.; Kaufmann, C.A.; Sadewasser, S.; Lux Steiner, M. Ch.

    2006-01-01

    We report on the buffer absorber interface formation in highly efficient 14.5 , AM1.5 ZnO CdS Cu In,Ga Se2 solar cells with a physical vapor deposited CdS buffer. For Se decapped Cu In,Ga Se2 CIGSe absorbers we observe sulfur passivation of the CIGSe grain boundaries during CdS growth and at the interface a thermally stimulated formation of a region with a higher band gap than that of the absorber bulk, determining the height of the potential barrier at the CdS CIGSe interface. For air ex...

  5. 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

  6. 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.

  7. Mobility-lifetime product and interface property in amorphous silicon solar cells

    Science.gov (United States)

    Okamoto, H.; Kida, H.; Nonomura, S.; Fukumoto, K.; Hamakawa, Y.

    1983-06-01

    A technique for evaluating the mobility-lifetime product of electrons and holes for amorphous Si solar cells is reported and used to assay the variation of the products with impurity doping, temperature, and prolonged light exposure. The product was examined as a significant indicator of solar cell performance and durability. The a-Si:H cells examined were prepared by an rf technique, and the spectral response of the photocurrent was examined in monochromatic light. The maximum products were observed when small amounts of boron atoms were used as the dopant. The hole lifetime dominated the photoconductivity in undoped and phosphorus doped cells, while the electron lifetime was dominant in boron doped cells. The mobility-lifetime product controlled the effective surface recombination factor. The method was concluded useful for optimizing the material, structure, and manufacturing processes for producing higher performance, reproducible, and stable a-Si:H pin solar cells.

  8. Interfacial Energy Alignment at the ITO/Ultra-Thin Electron Selective Dielectric Layer Interface and Its Effect on the Efficiency of Bulk-Heterojunction Organic Solar Cells.

    Science.gov (United States)

    Itoh, Eiji; Goto, Yoshinori; Saka, Yusuke; Fukuda, Katsutoshi

    2016-04-01

    We have investigated the photovoltaic properties of an inverted bulk heterojunction (BHJ) cell in a device with an indium-tin-oxide (ITO)/electron selective layer (ESL)/P3HT:PCBM active layer/MoOx/Ag multilayered structure. The insertion of only single layer of poly(diallyl-dimethyl-ammonium chloride) (PDDA) cationic polymer film (or poly(ethyleneimine) (PEI) polymeric interfacial dipole layer) and titanium oxide nanosheet (TN) films as an ESL effectively improved cell performance. Abnormal S-shaped curves were observed in the inverted BHJ cells owing to the contact resistance across the ITO/active layer interface and the ITO/PDDA/TN/active layer interface. The series resistance across the ITO/ESL interface in the inverted BHJ cell was successfully reduced using an interfacial layer with a positively charged surface potential with respect to ITO base electrode. The positive dipole in PEI and the electronic charge phenomena at the electrophoretic deposited TN (ED-TN) films on ITO contributed to the reduction of the contact resistance at the electrode interface. The surface potential measurement revealed that the energy alignment by the transfer of electronic charges from the ED-TN to the base electrodes. The insertion of the ESL with a large positive surface potential reduced the potential barrier for the electron injection at ITO/TN interface and it improved the photovoltaic properties of the inverted cell with an ITO/TN/active layer/MoOx/Ag structure.

  9. Structural and Optical Investigations of GaN-Si Interface for a Heterojunction Solar Cell

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Joshua J.; Jeffries, April M.; Bertoni, Mariana I.; Williamson, Todd L.; Bowden, Stuart G.; Honsberg, Christiana B.

    2014-06-08

    In recent years the development of heterojunction silicon based solar cells has gained much attention, lea largely by the efforts of Panasonic’s HIT cell. The success of the HIT cell prompts the scientific exploration of other thin film layers, besides the industrially accepted amorphous silicon. In this paper we report upon the use of gallium nitride, grown by MBE at “low temperatures” (~200°C), on silicon wafers as one possible candidate for making a heterojunction solar cell; the first approximation of band alignments between GaN and Si; and the material quality as determined by X-ray diffraction.

  10. Interfaces in nanoscale photovoltaics

    NARCIS (Netherlands)

    Öner, S.Z.

    2016-01-01

    This thesis deals with material interfaces in nanoscale photovoltaics. Interface properties between the absorbing semiconductor and other employed materials are crucial for an efficient solar cell. While the optical properties are largely unaffected by a few nanometer thin layer, the electronic prop

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

    Science.gov (United States)

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

    2016-06-25

    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.

  12. 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.

  13. Müller glial cells--the mediators of vascular disorders with vitreomacular interface pathology in diabetic maculopathy.

    Science.gov (United States)

    Robaszkiewicz, Jacek; Chmielewska, Katarzyna; Figurska, Małgorzata; Wierzbowska, Joanna; Stankiewicz, Andrzej

    2010-01-01

    The key to identifying the type of diabetic maculopathy is determining the status of posterior vitreous adhesion. In the pathological state, the breakdown of the internal and external blood-retina barrier is evident, however the mechanism is usually complex. The common denominator for these disorders are Müller glial cells, which mediate in maintaining the blood-retina barrier by linking the vessels, neurons and the vitreous in anatomical network and into functional dependence. The breakdown of the blood-retina barrier results in proliferation of Müller cells. Molecular changes in these cells increase endothelial barrier properties, but also induce pathological processes on the vitreo-retinal junction, resulting in increased adhesiveness of the collagen fibers of vitreous to retinal internal limiting membrane. The ability of Müller cells to reactive gliosis is influenced by the healthy functioning of the retinal pigment epithelium, which is a source of trophic factors necessary for appropriate Müller cells morphogenesis. Vitrectomy with the removal of ILM eliminates the vitreofoveal interface pathology, additionally provoking reactive gliosis within the macula. Intraoperative use of anti-VEGF supports short-term tightness of the blood-retina barrier in the perioperative neuralgic period. In the future, supplying astrocytes may be a strategy that will allow not only the inhibition of pathological neovascularization but also the restoration of the physiological network of capillaries in avascular retina areas. The delivery of recombinant PEDF allows for the recovery of Müller cells, and thus creates the conditions favourable for the survival of nerve cells in loss of retinal homeostasis.

  14. The effect of grain size on the biocompatibility, cell-materials interface, and mechanical properties of microwave-sintered bioceramics.

    Science.gov (United States)

    Veljović, Djordje; Colić, Miodrag; Kojić, Vesna; Bogdanović, Gordana; Kojić, Zvezdana; Banjac, Andrijana; Palcevskis, Eriks; Petrović, Rada; Janaćković, Djordje

    2012-11-01

    The effect of decreasing the grain size on the biocompatibility, cell-material interface, and mechanical properties of microwave-sintered monophase hydroxyapatite bioceramics was investigated in this study. A nanosized stoichiometric hydroxyapatite powder was isostatically pressed at high pressure and sintered in a microwave furnace in order to obtain fine grained dense bioceramics. The samples sintered at 1200°C, with a density near the theoretical one, were composed of micron-sized grains, while the grain size decreased to 130 nm on decreasing the sintering temperature to 900°C. This decrease in the grain size certainly led to increases in the fracture toughness by much as 54%. An in vitro investigation of biocompatibility with L929 and human MRC-5 fibroblast cells showed noncytotoxic effects for both types of bioceramics, while the relative cell proliferation rate, cell attachment and metabolic activity of the fibroblasts were improved with decreasing of grain size. An initial in vivo investigation of biocompatibility by the primary cutaneous irritation test showed that both materials exhibited no irritation properties.

  15. Efficient Light Harvester Layer Prepared by Solid/Mist Interface Reaction for Perovskite Solar Cells.

    Science.gov (United States)

    Xia, Xiang; Li, Hongcui; Wu, Wenyi; Li, Yanhua; Fei, Dehou; Gao, Chunxiao; Liu, Xizhe

    2015-08-12

    A solid/mist reaction method is developed to produce well-crystallized light harvester layers without pinhole defects for perovskite solar cells. The reaction based on mist precursor can be facilely operated with low process temperature. And it can effectively control the volume of CH3NH3I solution and the reaction temperature, which affect the quality of perovskite harvester layers and the performance of perovskite solar cells remarkably. Under optimized condition, the efficiencies of devices reach 16.2% with the average efficiency of 14.9%. The solid/mist reaction is also used to fabricate planar junction solar cells and a PCE of 14.9% is obtained.

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

    Energy Technology Data Exchange (ETDEWEB)

    Häussler, Dietrich [Institute for Materials Science, Christian-Albrechts-University Kiel, Kaiserstraße 2, 24143 Kiel (Germany); Houben, Lothar [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Research Centre Juelich GmbH, 52425 Juelich (Germany); Essig, Stephanie [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstraße 2, 79110 Freiburg (Germany); Kurttepeli, Mert [Institute for Materials Science, Christian-Albrechts-University Kiel, Kaiserstraße 2, 24143 Kiel (Germany); Dimroth, Frank [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstraße 2, 79110 Freiburg (Germany); Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Research Centre Juelich GmbH, 52425 Juelich (Germany); Jäger, Wolfgang, E-mail: wolfgang.jaeger@tf.uni-kiel.de [Institute for Materials Science, Christian-Albrechts-University Kiel, Kaiserstraße 2, 24143 Kiel (Germany)

    2013-11-15

    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

  17. Highly Fluorescent and Photostable Polymeric Nanofibers as Scaffolds for Cell Interfacing and Long-Term Tracking.

    Science.gov (United States)

    Diao, Hua Jia; Wang, Kai; Long, Hong Yan; Wang, Mingfeng; Chew, Sing Yan

    2016-03-09

    Highly fluorescent polymeric nanofibers fabricated via electrospinning of PCL-DPP-PCL (photostable polycaprolactones-di(thiophene-2-yl)-diketopyrrolopyrrole-photostable polycaprolactones) and commercial PCL mixture show superior photostability and cytocompatibility for long-term tracking of cell-substrate interaction. As a proof of concept, these PCL-DPP-PCL nanofibers enable clear visualization of intricate cell-substrate interactions such as oligodendrocyte myelination.

  18. Pericyte actomyosin-mediated contraction at the cell-material interface can modulate the microvascular niche

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sunyoung; Zeiger, Adam; Maloney, John M; Van Vliet, Krystyn J [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Kotecki, Maciej; Herman, Ira M, E-mail: krystyn@mit.ed, E-mail: ira.herman@tufts.ed [Department of Physiology, Tufts University School of Medicine, 145 Harrison Avenue, Boston, MA 02111 (United States)

    2010-05-19

    Pericytes physically surround the capillary endothelium, contacting and communicating with associated vascular endothelial cells via cell-cell and cell-matrix contacts. Pericyte-endothelial cell interactions thus have the potential to modulate growth and function of the microvasculature. Here we employ the experimental finding that pericytes can buckle a freestanding, underlying membrane via actin-mediated contraction. Pericytes were cultured on deformable silicone substrata, and pericyte-generated wrinkles were imaged via both optical and atomic force microscopy (AFM). The local stiffness of subcellular domains both near and far from these wrinkles was investigated by using AFM-enabled nanoindentation to quantify effective elastic moduli. Substratum buckling contraction was quantified by the normalized change in length of initially flat regions of the substrata (corresponding to wrinkle contour lengths), and a model was used to relate local strain energies to pericyte contractile forces. The nature of pericyte-generated wrinkling and contractile protein-generated force transduction was further explored by the addition of pharmacological cytoskeletal inhibitors that affected contractile forces and the effective elastic moduli of pericyte domains. Actin-mediated forces are sufficient for pericytes to exert an average buckling contraction of 38% on the elastomeric substrata employed in these in vitro studies. Actomyosin-mediated contractile forces also act in vivo on the compliant environment of the microvasculature, including the basement membrane and other cells. Pericyte-generated substratum deformation can thus serve as a direct mechanical stimulus to adjacent vascular endothelial cells, and potentially alter the effective mechanical stiffness of nonlinear elastic extracellular matrices, to modulate pericyte-endothelial cell interactions that directly influence both physiologic and pathologic angiogenesis.

  19. Morphological stability of an interface between two non-Newtonian fluids moving in a Hele-Shaw cell.

    Science.gov (United States)

    Martyushev, L M; Birzina, A I

    2015-01-01

    The problem of the morphological stability of an interface in the case of the displacement of one non-Newtonian fluid by another non-Newtonian fluid in a radial Hele-Shaw cell has been considered. Both fluids have been described by the two-parameter Ostwald-de Waele power-law model. The nonzero viscosity of the displacing fluid has been taken into account. A generalized Darcy's law for the system under consideration, as well as an equation for the determination of the critical size of morphological stability with respect to harmonic perturbations (linear analysis), has been derived. Morphological phase diagrams have been constructed, and the region of the parameters in which nonequilibrium reentrant morphological transitions are possible has been revealed.

  20. Numerical algorithms based on Galerkin methods for the modeling of reactive interfaces in photoelectrochemical (PEC) solar cells

    Science.gov (United States)

    Harmon, Michael; Gamba, Irene M.; Ren, Kui

    2016-12-01

    This work concerns the numerical solution of a coupled system of self-consistent reaction-drift-diffusion-Poisson equations that describes the macroscopic dynamics of charge transport in photoelectrochemical (PEC) solar cells with reactive semiconductor and electrolyte interfaces. We present three numerical algorithms, mainly based on a mixed finite element and a local discontinuous Galerkin method for spatial discretization, with carefully chosen numerical fluxes, and implicit-explicit time stepping techniques, for solving the time-dependent nonlinear systems of partial differential equations. We perform computational simulations under various model parameters to demonstrate the performance of the proposed numerical algorithms as well as the impact of these parameters on the solution to the model.

  1. Interfacing Sca-1pos Mesenchymal Stem Cells with Biocompatible Scaffolds with Different Chemical Composition and Geometry

    Directory of Open Access Journals (Sweden)

    G. Forte

    2009-01-01

    Full Text Available An immortalized murine mesenchymal stem cell line (mTERT-MSC enriched for Linneg/Sca-1pos fraction has been obtained through the transfection of MSC with murine TERT and single-cell isolation. Such cell line maintained the typical MSC self-renewal capacity and continuously expressed MSC phenotype. Moreover, mTERT-MSC retained the functional features of freshly isolated MSC in culture without evidence of senescence or spontaneous differentiation events. Thus, mTERT-MSC have been cultured onto PLA films, 30 and 100 μm PLA microbeads, and onto unpressed and pressed HYAFF-11 scaffolds. While the cells adhered preserving their morphology on PLA films, clusters of mTERT-MSC were detected on PLA beads and unpressed fibrous scaffolds. Finally, mTERT-MSC were not able to colonize the inner layers of pressed HYAFF-11. Nevertheless, such cell line displayed the ability to preserve Sca-1 expression and to retain multilineage potential when appropriately stimulated on all the scaffolds tested.

  2. Size dependent gold nanoparticle interaction at nano-micro interface using both monolayer and multilayer (tissue-like) cell models

    Science.gov (United States)

    Yohan, Darren; Yang, Celina; Lu, Xiaofeng; Chithrani, Devika B.

    2016-03-01

    Gold nanoparticles (GNPs) can be used as a model NP system to improve the interface between nanotechnology and medicine since their size and surface properties can be tailored easily. GNPs are being used as radiation dose enhancers and as drug carriers in cancer research. Hence, it is important to know the optimum NP size for uptake not only at monolayer level but also at tissue level. Once GNPs leave tumor vasculature, they enter the tumor tissue. Success of any therapeutic technique using NPs depends on how well NPs penetrate the tumor tissue and reach individual tumor cells. In this work, multicellular layers (MCLs) were grown to model the post-vascular tumor environment. GNPs of 20 nm and 50 nm diameters were used to elucidate the effects of size on the GNP penetration and distribution dynamics. Larger NPs (50 nm) were better at monolayer level, but smaller NPs (20 nm) were at tissue level. The MCLs exhibited a much more extensive extracellular matrix (ECM) than monolayer cell cultures. This increased ECM created a barrier for NP transport and ECM was also dependent on the tumor cell lines. Smaller NPs penetrated better compared to larger NPs. Transport of NPs was better in MDA-MB231 vs MCF-7. This MCL model tissue structures are better tools to optimize NP transport through tissue before using them in animal models. Based on our study, we believe that smaller NPs are better for improved outcome in future cancer therapeutics.

  3. High-performance cadmium sulphide-based planar perovskite solar cell and the cadmium sulphide/perovskite interfaces

    Science.gov (United States)

    Peng, Haitao; Sun, Weihai; Li, Yunlong; Yan, Weibo; Yu, Pingrong; Zhou, Huanping; Bian, Zuqiang; Huang, Chunhui

    2016-04-01

    Planar heterojunction perovskite solar cell is one of the most competitive photovoltaic technologies, while charge transport materials play a crucial role. We successfully demonstrated an effective electron transport material, namely chemical bath deposited cadmium sulphide (CdS) film under low temperature, in perovskite-based solar cells. Power conversion efficiency of 16.1% has been achieved, which is comparable to that of devices based on TiO2 film prepared via low-temperature processes. Electronic impedance spectra reveal that the CdS-based device presents a higher recombination resistance than TiO2-based devices, which reduces carrier recombination and increases the open circuit voltage. The interface between CdS and perovskite was characterized with improved characteristics when compared to TiO2, e.g., efficient carrier extraction and reduced surface defect-associated degradation in the devices, which help to alleviate anomalous hysteresis and long-term instability. Furthermore, the entire device was fabricated via solution process with a processing temperature below 100°C, suggesting a promising method of further development of perovskite solar cells and commercial manufacturing.

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

    Science.gov (United States)

    Gross, Benjamin J.; El-Naggar, Mohamed Y.

    2015-06-01

    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.

  5. 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.

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

    OpenAIRE

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

    2015-01-01

    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: (...

  7. 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.

  8. Electron transfer at the cell-uranium interface in Geobacter spp.

    Science.gov (United States)

    Reguera, Gemma

    2012-12-01

    The in situ stimulation of Fe(III) oxide reduction in the subsurface stimulates the growth of Geobacter spp. and the precipitation of U(VI) from groundwater. As with Fe(III) oxide reduction, the reduction of uranium by Geobacter spp. requires the expression of their conductive pili. The pili bind the soluble uranium and catalyse its extracellular reductive precipitation along the pili filaments as a mononuclear U(IV) complexed by carbon-containing ligands. Although most of the uranium is immobilized by the pili, some uranium deposits are also observed in discreet regions of the outer membrane, consistent with the participation of redox-active foci, presumably c-type cytochromes, in the extracellular reduction of uranium. It is unlikely that cytochromes released from the outer membrane could associate with the pili and contribute to the catalysis, because scanning tunnelling microscopy spectroscopy did not reveal any haem-specific electronic features in the pili, but, rather, showed topographic and electronic features intrinsic to the pilus shaft. Pili not only enhance the rate and extent of uranium reduction per cell, but also prevent the uranium from traversing the outer membrane and mineralizing the cell envelope. As a result, pili expression preserves the essential respiratory activities of the cell envelope and the cell's viability. Hence the results support a model in which the conductive pili function as the primary mechanism for the reduction of uranium and cellular protection in Geobacter spp.

  9. Interfacing polymeric scaffolds with primary pancreatic ductal adenocarcinoma cells to develop 3D cancer models

    NARCIS (Netherlands)

    Ricci, C.; Mota, C.M.; Moscato, S.; Alessandro, D' D.; Ugel, S.; Sartoris, S.; Bronte, V.; Boggi, U.; Campani, D.; Funel, N.; Moroni, L.; Danti, S.

    2014-01-01

    We analyzed the interactions between human primary cells from pancreatic ductal adenocarcinoma (PDAC) and polymeric scaffolds to develop 3D cancer models useful for mimicking the biology of this tumor. Three scaffold types based on two biocompatible polymeric formulations, such as poly(vinyl alcohol

  10. Boron Concentration Measurements at the I/P Interface in Nip a-Si Solar Cells

    DEFF Research Database (Denmark)

    Aken, Van; Duchamp, Martial; Boothroyd, Chris

    2011-01-01

    The p-type Si layer in n-i-p a-Si and μc-Si solar cells on foil has several important requirements with respect to conductivity and optical transmission. We control the optical band gap and activation energy of p-a-SiC by varying the B2H6 and CH4 flows in the process chamber. Modelling shows...... that the optimum efficiency in n-i-p solar cells is obtained when the p-a-SiC band gap is just above the band gap of the absorber layer. We have assessed the potential of core-loss electron energy-loss spectroscopy (EELS) for detecting B and C and of low-loss EELS, in a spatially resolved manner, as probe of local...

  11. High Performance Nano-Crystalline Oxide Fuel Cell Materials. Defects, Structures, Interfaces, Transport, and Electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Scott [Northwestern Univ., Evanston, IL (United States); Poeppelmeier, Ken [Northwestern Univ., Evanston, IL (United States); Mason, Tom [Northwestern Univ., Evanston, IL (United States); Marks, Lawrence [Northwestern Univ., Evanston, IL (United States); Voorhees, Peter [Northwestern Univ., Evanston, IL (United States)

    2016-09-07

    This project addresses fundamental materials challenges in solid oxide electrochemical cells, devices that have a broad range of important energy applications. Although nano-scale mixed ionically and electronically conducting (MIEC) materials provide an important opportunity to improve performance and reduce device operating temperature, durability issues threaten to limit their utility and have remained largely unexplored. Our work has focused on both (1) understanding the fundamental processes related to oxygen transport and surface-vapor reactions in nano-scale MIEC materials, and (2) determining and understanding the key factors that control their long-term stability. Furthermore, materials stability has been explored under the “extreme” conditions encountered in many solid oxide cell applications, i.e, very high or very low effective oxygen pressures, and high current density.

  12. Tailoring the Interface to Improve Voc in Dye-Sensitized Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Neale, N. R.; Kopidakis, N.; van de Lagemaat, J.; Frank, A. J.

    2005-01-01

    Adding certain adsorbents in conjunction with the sensitizing dye employed in high-efficiency TiO2 nanoparticle solar cells has been shown to increase the photovoltage. It is has been speculated that the increased photovoltage is due to these hydrophobic adsorbents passivating surface states that mitigate the recombination of photoinjected electrons with redox species in the electrolyte. In collaboration with the DOE Office of Science Program, we are conducting transient-photovoltage measurements to determine the mechanism for the improved photovoltage.

  13. Brownian nanoimaging of interface dynamics and ligand-receptor binding at cell surfaces in 3-D.

    Science.gov (United States)

    Kuznetsov, Igor R; Evans, Evan A

    2013-04-01

    We describe a method for nanoimaging interfacial dynamics and ligand-receptor binding at surfaces of live cells in 3-D. The imaging probe is a 1-μm diameter glass bead confined by a soft laser trap to create a "cloud" of fluctuating states. Using a facile on-line method of video image analysis, the probe displacements are reported at ~10 ms intervals with bare precisions (±SD) of 4-6 nm along the optical axis (elevation) and 2 nm in the transverse directions. We demonstrate how the Brownian distributions are analyzed to characterize the free energy potential of each small probe in 3-D taking into account the blur effect of its motions during CCD image capture. Then, using the approach to image interactions of a labeled probe with lamellae of leukocytic cells spreading on cover-glass substrates, we show that deformations of the soft distribution in probe elevations provide both a sensitive long-range sensor for defining the steric topography of a cell lamella and a fast telemetry for reporting rare events of probe binding with its surface receptors. Invoking established principles of Brownian physics and statistical thermodynamics, we describe an off-line method of super resolution that improves precision of probe separations from a non-reactive steric boundary to ~1 nm.

  14. 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.

  15. The ER-mitochondria interface: the social network of cell death.

    Science.gov (United States)

    Grimm, Stefan

    2012-02-01

    When cellular organelles communicate bad things can happen. Recent findings uncovered that the junction between the endoplasmic reticulum (ER) and the mitochondria holds a crucial role for cell death regulation. Not only does this locale connect the two best-known organelles in apoptosis, numerous regulators of cell death are concentrated at this spot, providing a terrain for intense signal transfers. Ca2+ is the most prominent signalling factor that is released from the ER and, at high concentration, mediates the transfer of an apoptosis signal to mitochondria as the executioner organelle for cell death. An elaborate array of checks and balances is fine-tuning this process including Bcl-2 family members. Moreover, MAMs, "mitochondria-associated membranes", are distinct membrane sections at the ER that are in close contact with mitochondria and have been found to exchange lipids and lipid-derived molecules such as ceramide for apoptosis induction. Recent work has also described a reverse transfer of apoptosis signals, from mitochondria to the ER, via cytochrome c release and prolonged IP3R opening or through the mitochondrial fission factor Fis1 and Bap31 at the ER, which form the ARCosome, a novel caspase-activation complex.

  16. 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.

  17. Cytotoxic Evaluation of e-Liquid Aerosol using Different Lung-Derived Cell Models

    Directory of Open Access Journals (Sweden)

    Stefanie Scheffler

    2015-10-01

    Full Text Available The in vitro toxicological evaluation of e-liquid aerosol is an important aspect of consumer protection, but the cell model is of great significance. Due to its water solubility, e-liquid aerosol is deposited in the conducting zone of the respiratory tract. Therefore, primary normal human bronchial epithelial (NHBE cells are more suitable for e-liquid aerosol testing than the widely used alveolar cell line A549. Due to their prolonged lifespan, immortalized cell lines derived from primary NHBE cells, exhibiting a comparable in vitro differentiation, might be an alternative for acute toxicity testing. In our study, A549 cells freshly isolated NHBE cells and the immortalized cell line CL-1548 were exposed at the air-liquid interface to e-liquid aerosol and cigarette mainstream smoke in a CULTEX® RFS compact module. The cell viability was analyzed 24 h post-exposure. In comparison with primary NHBE cells, the CL-1548 cell line showed lower sensitivity to e-liquid aerosol but significantly higher sensitivity compared to A549 cells. Therefore, the immortalized cell line CL-1548 is recommended as a tool for the routine testing of e-liquid aerosol and is preferable to A549 cells.

  18. 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

  19. 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.

  20. 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)

  1. Highly ordered large-scale neuronal networks of individual cells - toward single cell to 3D nanowire intracellular interfaces.

    Science.gov (United States)

    Kwiat, Moria; Elnathan, Roey; Pevzner, Alexander; Peretz, Asher; Barak, Boaz; Peretz, Hagit; Ducobni, Tamir; Stein, Daniel; Mittelman, Leonid; Ashery, Uri; Patolsky, Fernando

    2012-07-25

    The use of artificial, prepatterned neuronal networks in vitro is a promising approach for studying the development and dynamics of small neural systems in order to understand the basic functionality of neurons and later on of the brain. The present work presents a high fidelity and robust procedure for controlling neuronal growth on substrates such as silicon wafers and glass, enabling us to obtain mature and durable neural networks of individual cells at designed geometries. It offers several advantages compared to other related techniques that have been reported in recent years mainly because of its high yield and reproducibility. The procedure is based on surface chemistry that allows the formation of functional, tailormade neural architectures with a micrometer high-resolution partition, that has the ability to promote or repel cells attachment. The main achievements of this work are deemed to be the creation of a large scale neuronal network at low density down to individual cells, that develop intact typical neurites and synapses without any glia-supportive cells straight from the plating stage and with a relatively long term survival rate, up to 4 weeks. An important application of this method is its use on 3D nanopillars and 3D nanowire-device arrays, enabling not only the cell bodies, but also their neurites to be positioned directly on electrical devices and grow with registration to the recording elements underneath.

  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

    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...

  3. Chemical interaction at the buried silicon/zinc oxide thin-film solar cell interface as revealed by hard X-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wimmer, M., E-mail: mark.wimmer@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Gerlach, D.; Wilks, R.G.; Scherf, S.; Félix, R. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Lupulescu, C. [Institute for Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Ruske, F.; Schondelmaier, G.; Lips, K. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Hüpkes, J. [Institute for Energy Research, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany); Gorgoi, M. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Eberhardt, W. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institute for Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Rech, B. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Bär, M., E-mail: marcus.baer@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus, Konrad-Wachsmann-Allee 1, 03046 Cottbus (Germany)

    2013-10-15

    Highlights: •We used HAXPES to identify chemical interactions at the buried silicon/aluminum-doped zinc oxide thin-film solar cell interface. •The results indicate a diffusion of zinc and aluminum into the silicon upon annealing procedures which are part of the solar cell processing. •The contamination of the silicon may be detrimental for the solar cell performance. -- Abstract: Hard X-ray photoelectron spectroscopy (HAXPES) is used to identify chemical interactions (such as elemental redistribution) at the buried silicon/aluminum-doped zinc oxide thin-film solar cell interface. Expanding our study of the interfacial oxidation of silicon upon its solid-phase crystallization (SPC), in which we found zinc oxide to be the source of oxygen, in this investigation we address chemical interaction processes involving zinc and aluminum. In particular, we observe an increase of zinc- and aluminum-related HAXPES signals after SPC of the deposited amorphous silicon thin films. Quantitative analysis suggests an elemental redistribution in the proximity of the silicon/aluminum-doped zinc oxide interface – more pronounced for aluminum than for zinc – as explanation. Based on these insights the complex chemical interface structure is discussed.

  4. 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.

  5. Boron concentration measurements at the I/P interface in nip a-Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Van Aken, B.B.; Soppe, W.J. [ECN Solar Energy, P.O. Box 1, NL-1755 ZG Petten (Netherlands); Duchamp, M.; Boothroyd, C.B. [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Dunin-Borkowski, R.E. [Institute for Microstructure Research, Forschungszentrum Juelich, D-52425 Juelich (Germany); Barnes, J.P.; Veillerot, M. [CEA-Leti, MINATEC Campus, 17 rue des Martyrs, FR-38054 Grenoble Cedex 9 (France)

    2011-09-15

    The p-type Si layer in n-i-p a-Si and {mu}c-Si solar cells on foil has several important requirements with respect to conductivity and optical transmission. We control the optical band gap and activation energy of p-a-SiC by varying the B2H6 and CH4 flows in the process chamber. Modelling shows that the optimum efficiency in n-i-p solar cells is obtained when the p-a-SiC band gap is just above the band gap of the absorber layer. We have assessed the potential of core-loss electron energy-loss spectroscopy (EELS) for detecting B and C and of low-loss EELS, in a spatially resolved manner, as probe of local variations in bulk plasmon energy. EELS in the transmission electron microscope (TEM) combines the necessary spatial resolution to investigate the boundary between p-a-SiC and i-a-Si with sufficient sensitivity to the boron content.

  6. The Interface between FTO and the TiO2 Compact Layer Can Be One of the Origins to Hysteresis in Planar Heterojunction Perovskite Solar Cells.

    Science.gov (United States)

    Jena, Ajay Kumar; Chen, Hsin-Wei; Kogo, Atsushi; Sanehira, Yoshitaka; Ikegami, Masashi; Miyasaka, Tsutomu

    2015-05-13

    Organometal halide perovskite solar cells have shown rapid rise in power conversion efficiency, and therefore, they have gained enormous attention in the past few years. However, hysteretic photovoltaic characteristics, found in these solid-state devices, have been a major problem. Although it is being proposed that the ferroelectric property of perovskite causes hysteresis in the device, we observed hysteresis in a device made of nonferroelectric PbI2 as a light absorber. This result evidently supports the fact that ferroelectric property cannot be the sole reason for hysteresis. The present study investigates the roles of some key interfaces in a planar heterojunction perovskite (CH3NH3PbI(3-x)Cl(x)) solar cell that can potentially cause hysteresis. The results confirm that the interface between fluorine doped tin oxide (FTO) substrate and the TiO2 compact layer has a definite contribution to hysteresis. Although this interface is one of the origins to hysteresis, we think that other interfaces, especially the interface of the TiO2 compact layer with perovskite, can also play major roles. Nevertheless, the results indicate that hysteresis in such devices can be reduced/eliminated by changing the interlayer between FTO and perovskite.

  7. 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.)

  8. 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...

  9. Effect of TCO/μc-Si:H Interface Modification on Hydrogenated Microcrystalline Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Shin-Wei Liang

    2013-01-01

    Full Text Available The effects of H2 plasma exposure on optical, electrical, and structural properties of fluorine-doped tin oxide (FTO and AZO/FTO substrates have been investigated. With increasing the time of H2-plasma exposure, the hydrogen radical and ions penetrated through the FTO surface to form more suboxides such as SnO and metallic Sn, which was confirmed by the XPS analysis. The Sn reduction on the FTO surface can be effectively eliminated by capping the FTO with a very thin layer of sputtered aluminum-doped zinc oxide (AZO, as confirmed by the XPS analysis. By using the AZO/FTO as front TCO with the subsequent annealing, the p-i-n μc-Si:H cell exhibited a significantly enhanced JSC from 15.97 to 19.40 mA/cm2 and an increased conversion efficiency from 5.69% to 7.09%. This significant enhancement was ascribed to the effective elimination of the Sn reduction on the FTO surface by the thin AZO layer during the Si-based thin-film deposition with hydrogen-rich plasma exposure. Moreover, the subsequent annealing of the sputtered AZO could lead to less defects as well as a better interface of AZO/FTO.

  10. Formation of the physical vapor deposited CdS /Cu(In,Ga)Se2 interface in highly efficient thin film solar cells

    Science.gov (United States)

    Rusu, M.; Glatzel, Th.; Neisser, A.; Kaufmann, C. A.; Sadewasser, S.; Lux-Steiner, M. Ch.

    2006-04-01

    We report on the buffer/absorber interface formation in highly efficient (14.5%, air mass 1.5) ZnO /CdS/Cu(In,Ga)Se2 solar cells with a physical vapor deposited CdS buffer. For Se-decapped Cu (In,Ga)Se2 (CIGSe) absorbers we observe sulfur passivation of the CIGSe grain boundaries during CdS growth and at the interface a thermally stimulated formation of a region with a higher band gap than that of the absorber bulk, determining the height of the potential barrier at the CdS /CIGSe interface. For air-exposed CIGSe samples the grain boundary passivation is impeded by a native oxide/adsorbate layer at the CIGSe surface determining the thermal stability of the potential barrier height.

  11. 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...

  12. Fluid Interfaces

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius

    2001-01-01

    Fluid interaction, interaction by the user with the system that causes few breakdowns, is essential to many user interfaces. We present two concrete software systems that try to support fluid interaction for different work practices. Furthermore, we present specificity, generality, and minimality...... as design goals for fluid interfaces....

  13. Testing Interfaces

    DEFF Research Database (Denmark)

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

    1999-01-01

    The wide use of solid insulating materials combinations in combinations has introduced problems in the interfaces between components. The most common insulating materials are cross-linked polyethylene (XLPE), silicone rubber (SIR) and ethylene-propylene rubbers (EPR). Assemblies of these materials...... have caused major failures. In the Netherlands, a major black out was caused by interface problems in 150kV cable terminations, causing a cascade of breakdowns. There is a need to investigate the reasons for this and other similar breakdowns.The major problem is expected to lie in the interface between...... two different materials. Environmental influence, surface treatment, defects in materials and interface, design, pressure and rubbing are believed to have an effect on interface degradation. These factors are believed to increase the possibility of partial discharges (PD). PD will, with time, destroy...

  14. Comparative SAXS and DSC study on stratum corneum structural organization in an epidermal cell culture model (ROC): impact of cultivation time.

    Science.gov (United States)

    Kuntsche, Judith; Herre, Angela; Fahr, Alfred; Funari, Sérgio S; Garidel, Patrick

    2013-12-18

    Cell cultured skin equivalents present an alternative for dermatological in vitro evaluations of drugs and excipients as they provide the advantage of availability, lower variability and higher assay robustness compared to native skin. For penetration/permeation studies, an adequate stratum corneum barrier similar to that of human stratum corneum is, however, a prerequisite. In this study, the stratum corneum lipid organization in an epidermal cell culture model based on rat epidermal keratinocytes (REK organotypic culture, ROC) was investigated by small-angle X-ray scattering (SAXS) in dependence on ROC cultivation time and in comparison to native human and rat stratum cornea. In addition, the thermal phase behavior was studied by differential scanning calorimetry (DSC) and barrier properties were checked by measurements of the permeability of tritiated water. The development of the barrier of ROC SC obtained at different cultivation times (7, 14 and 21 days at the air-liquid interface) was connected with an increase in structural order of the SC lipids in SAXS measurements: Already cultivation for 14 days at the air-liquid interface resulted overall in a competent SC permeability barrier and SC lipid organization. Cultivation for 21 days resulted in further minor changes in the structural organization of ROC SC. The SAXS patterns of ROC SC had overall large similarities with that of human SC and point to the presence of a long periodicity phase with a repeat distance of about 122Å, e.g. slightly smaller than that determined for human SC in the present study (127Å). Moreover, SAXS results also indicate the presence of covalently bound ceramides, which are crucial for a proper SC barrier, although the corresponding thermal transitions were not clearly detectable by DSC. Due to the competent SC barrier properties and high structural and organizational similarity to that of native human SC, ROC presents a promising alternative for in vitro studies, particularly as

  15. Impact of Annealing-Induced Intermixing on the Electronic Level Alignment at the In2S3/Cu(In,Ga)Se2 Thin-Film Solar Cell Interface.

    Science.gov (United States)

    Bär, Marcus; Barreau, Nicolas; Couzinié-Devy, François; Weinhardt, Lothar; Wilks, Regan G; Kessler, John; Heske, Clemens

    2016-01-27

    The interface between a nominal In2S3 buffer and a Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorber was investigated by direct and inverse photoemission to determine the interfacial electronic structure. On the basis of a previously reported heavy intermixing at the interface (S diffuses into the absorber; Cu diffuses into the buffer; and Na diffuses through it), we determine here the band alignment at the interface. The results suggest that the pronounced intermixing at the In2S3/CIGSe interface leads to a favorable electronic band alignment, necessary for high-efficiency solar cell devices.

  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

    2012-01-18

    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.

  17. 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

  18. 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.

  19. Monocyte Subsets Coregulate Inflammatory Responses by Integrated Signaling through TNF and IL-6 at the Endothelial Cell Interface

    Science.gov (United States)

    Chimen, Myriam; Yates, Clara M.; McGettrick, Helen M.; Ward, Lewis S. C.; Harrison, Matthew J.; Apta, Bonita; Dib, Lea H.; Imhof, Beat A.; Harrison, Paul; Nash, Gerard B.

    2017-01-01

    Two major monocyte subsets, CD14+CD16− (classical) and CD14+/dimCD16+ (nonclassical/intermediate), have been described. Each has different functions ascribed in its interactions with vascular endothelial cells (EC), including migration and promoting inflammation. Although monocyte subpopulations have been studied in isolated systems, their influence on EC and on the course of inflammation has been ignored. In this study, using unstimulated or cytokine-activated EC, we observed significant differences in the recruitment, migration, and reverse migration of human monocyte subsets. Associated with this, and based on their patterns of cytokine secretion, there was a difference in their capacity to activate EC and support the secondary recruitment of flowing neutrophils. High levels of TNF were detected in cocultures with nonclassical/intermediate monocytes, the blockade of which significantly reduced neutrophil recruitment. In contrast, classical monocytes secreted high levels of IL-6, the blockade of which resulted in increased neutrophil recruitment. When cocultures contained both monocyte subsets, or when conditioned supernatant from classical monocytes cocultures (IL-6hi) was added to nonclassical/intermediate monocyte cocultures (TNFhi), the activating effects of TNF were dramatically reduced, implying that when present, the anti-inflammatory activities of IL-6 were dominant over the proinflammatory activities of TNF. These changes in neutrophil recruitment could be explained by regulation of E-selectin on the cocultured EC. This study suggests that recruited human monocyte subsets trigger a regulatory pathway of cytokine-mediated signaling at the EC interface, and we propose that this is a mechanism for limiting the phlogistic activity of newly recruited monocytes. PMID:28193827

  20. The Effect of Lymphocyte Immunotherapy on CD80+ Cells at the Fetomaternal Interface and Cyesis Result of Mice Model of Spontaneous Abortion

    Institute of Scientific and Technical Information of China (English)

    林羿; 曾耀英; 何贤辉; 曾山; 詹美意; 关洁宾; 狄静芳; 肇静娴; 全世明

    2001-01-01

    Objectives To explore the relationship between CD80 expression on lymphocytes at the fetomaternal interface and the fertility characteristics in CBA/J × DBA/2 mice as a model of recurrent spontaneous abortion (RSA) and to investigate the effects of lym phocyte immunotherapy (LIT) on the level of CD80 expression.Materials & Methods The characteristics of fertility in CBA/J × DBA/2 mice were observed in a 120-day period and compared with four normal fertile groups. In anoth er 15 pairs of CBA/J × DBA/2 breedings, resorption rate on day 13 of pregnancy were calculated and the proportion of CD80+ cells at the fetomaternal interface were determined by using two-color flow cytometric analysis, mainly stained with CD80 FITC and CD45-PE. In order to determine the identity of CD80+ cells, the expression levels of CD3(T cell marker), DX 5(NK cell marker), and MHC-Ⅱ(antigen present ing cell marker) were detected in this cell population. Furthermore, the resorption rate and the proportion of CD80+ cells among CBA/J × DBA/2 breedings with and with out immunotherapy were also determined and compared with normal fertile controls.Results The characteristics of abortion in CBA/J × DBA/2 mice were recurrent abor tion on about day 10 of gestation. The resorption rate in CBA/J × DBA/2 mice was significantly higher than that in BALB/c×DBA/2 mice (30. 8% ± 16. 6% vs. 7. 7%± 6. 7%, P< 0. 01). Accordingly, the proportion of CD80+ cells evaluated at the fetomaternal interface in CBA/J × DBA/2 mice was also significantly higher (11. 7%± 5. 8% vs. 3. 9% ± 1. 8%, P< 0. 01). Resorption rate of CBA/J × DBA/2 mice un derwent of LIT was significantly lower than that without LIT, and this decreased rate was correlated with decreased proportion of CD80+ cells.Conclusion In CBA/J × DBA/2 mice model, the characteristics of abortion seem to be peri-implantation embryo-resorption. A correlation between early embryonic waste and higher CD80 proportion at the fetomaternal interface

  1. IFPA meeting 2015 workshop report IV: placenta and obesity; stem cells of the feto-maternal interface; placental immunobiology and infection.

    Science.gov (United States)

    Abumaree, M H; Almutairi, A; Cash, S; Boeuf, P; Chamley, L W; Gamage, T; James, J L; Kalionis, B; Khong, T Y; Kolahi, K S; Lim, R; Liong, S; Morgan, T K; Motomura, K; Peiris, H N; Pelekanos, R A; Pelzer, E; Shafiee, A; Lash, G E; Natale, D

    2016-12-01

    Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At the 2015 IFPA annual meeting there were 12 themed workshops, three of which are summarized in this report. These workshops related to various aspects of placental biology and collectively covered areas of obesity and the placenta, stem cells of the feto-maternal interface, and placental immunobiology and infection.

  2. Interface Realisms

    DEFF Research Database (Denmark)

    Pold, Søren

    2005-01-01

    This article argues for seeing the interface as an important representational and aesthetic form with implications for postmodern culture and digital aesthetics. The interface emphasizes realism due in part to the desire for transparency in Human-Computer Interaction (HCI) and partly to the devel......This article argues for seeing the interface as an important representational and aesthetic form with implications for postmodern culture and digital aesthetics. The interface emphasizes realism due in part to the desire for transparency in Human-Computer Interaction (HCI) and partly...... to the development of illusionistic realism within computer graphics and games. The article compares the pragmatic realism of HCI with aesthetic notions of realism in the computer game Max Payne (illusionistic realism), the artist Jodi's game modifications (media realism), and Adrian Ward's software art work......, "Signwave Auto Illustrator" (functional realism)....

  3. A single cell functions as a tissue-specific stem cell and the in vitro niche-forming cell.

    Science.gov (United States)

    Ghosh, Moumita; Helm, Karen M; Smith, Russell W; Giordanengo, Matthew S; Li, Bilan; Shen, Hongmei; Reynolds, Susan D

    2011-09-01

    Tissue-specific stem cell (TSC) behavior is determined by the stem cell niche. However, delineation of the TSC-niche interaction requires purification of both entities. We reasoned that the niche could be defined by the location of the TSC. We demonstrate that a single CD49f(bright)/Sca1(+)/ALDH(+) basal cell generates rare label-retaining cells and abundant label-diluting cells. Label-retaining and label-diluting cells were located in the rimmed domain of a unique clone type, the rimmed clone. The TSC property of self-renewal was tested by serial passage at clonal density and analysis of clone-forming cell frequency. A single clone could be passaged up to five times and formed only rimmed clones. Thus, rimmed clone formation was a cell-intrinsic property. Differentiation potential was evaluated in air-liquid interface cultures. Homogenous cultures of rimmed clones were highly mitotic but were refractory to standard differentiation signals. However, rimmed clones that were cocultured with unfractionated tracheal cells generated each of the cell types found in the tracheal epithelium. Thus, the default niche is promitotic: Multipotential differentiation requires adaptation of the niche. Because lung TSCs are typically evaluated after injury, the behavior of CD49f(bright)/Sca1(+)/ALDH(+) cells was tested in normal and naphthalene-treated mice. These cells were mitotically active in the normal and repaired epithelium, their proliferation rate increased in response to injury, and they retained label for 34 days. We conclude that the CD49f(bright)/Sca1(+)/ALDH(+) tracheal basal cell is a TSC, that it generates its own niche in vitro, and that it participates in tracheal epithelial homeostasis and repair.

  4. 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.

  5. 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

    2011-01-04

    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.

  6. On the Role of Interfaces in Planar-Structured HC(NH2 )2 PbI3 Perovskite Solar Cells.

    Science.gov (United States)

    Seol, Dong-Jin; Lee, Jin-Wook; Park, Nam-Gyu

    2015-07-20

    Planar-structured HC(NH2 )2 PbI3 (FAPbI3 ) perovskite solar cells were prepared via a two-step deposition process. To investigate the role of interface, the perovskite morphology was intentionally modified by varying HC(NH2 )2 I concentration. Surface and grain sizes of the deposited FAPbI3 became rougher and larger as the HC(NH2 )2 I concentration decreased from 58.2 to 40.7 mM. Average photocurrent was improved but photovoltage deteriorated slightly with decreasing concentration. Consequently, the average efficiency was improved from 7.82 % to 10.70 % and the best efficiency of 12.17 % was obtained at 40.7 mM. Photoluminescence (PL) at TiO2 /FAPbI3 interface was reduced with decreasing concentration, which was, however, reversed at FAPbI3 /spiro-MeOTAD one. By correlating PL data and the photovoltaic performance, we concluded that the TiO2 /perovskite interface plays a crucial role in determining photocurrent while the perovskite/spiro-MeOTAD interface is important in governing photovoltage.

  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. Comparison of on-line flow-cell and off-line solvent-elimination interfaces for size-exclusion chromatography and Fourier-transform infrared spectroscopy in polymer analysis.

    Science.gov (United States)

    Kok, S J; Wold, C A; Hankemeier, Th; Schoenmakers, P J

    2003-10-31

    Two commercial liquid chromatography-Fourier-transform infrared spectroscopy interfaces (LC-FTIR), viz. a flow cell and a solvent-elimination interface have been assessed for use in size-exclusion chromatography (SEC) with respect to their chromatographic integrity (i.e. peak asymmetry, chromatographic resolution), quantitative and qualitative aspects. A polycarbonate/aliphatic polyester (PC/APE) blend and a polycarbonate-co-polydimethylsiloxane (PC-co-PDMS) copolymer were selected for the assessment. Both samples were successfully and selectively analyzed. The relatively large volume of the flow cell and the inherent deposition characteristics of the solvent-elimination interface led to a comparable decrease in the chromatographic resolution. The separation of oligomers was diminished in comparison with SEC-ultra-violet (UV). However, the peak asymmetry was not significantly affected by either interface. For both interfaces, a linear relationship was obtained for the FTIR response versus the injected concentration. The sensitivity was found to be higher for the solvent-elimination interface. For the current model compounds, the flow-cell interface detection limits are worse. However, the repeatability of flow-cell SEC-FTIR, evaluated by means of four SEC-FTIR analyses of polycarbonate, was considerably better than for solvent-elimination SEC-FTIR. This is probably due to the well-defined optical path length of the sample in the flow cell. By spectral subtraction, it was very well possible to obtain qualitative (functional group) information for compound identification also with flow-cell SEC-FTIR.

  9. Comparison of on-line flow-cell and off-line solvent-elimination interfaces for size-exclusion chromatography and Fourier-transform infrared spectroscopy in polymer analysis

    NARCIS (Netherlands)

    Kok, S.J.; Wold, C.A.; Hankemeier, Th.; Schoenmakers, P.J.

    2003-01-01

    Two commercial liquid chromatography-Fourier-transform infrared spectroscopy interfaces (LC-FTIR), viz. a flow cell and a solvent-elimination interface have been assessed for use in size-exclusion chromatography (SEC) with respect to their chromatographic integrity (i.e. peak asymmetry, chromatograp

  10. Inhibitory NK receptor recognition of HLA-G: regulation by contact residues and by cell specific expression at the fetal-maternal interface.

    Directory of Open Access Journals (Sweden)

    Tsufit Gonen-Gross

    Full Text Available The non-classical HLA-G protein is distinguished from the classical MHC class I molecules by its expression pattern, low polymorphism and its ability to form complexes on the cell surface. The special role of HLA-G in the maternal-fetal interface has been attributed to its ability to interact with specific receptors found on maternal immune cells. However this interaction is restricted to a limited number of receptors. In this study we elucidate the reason for this phenomenon by comparing the specific contact residues responsible for MHC-KIR interactions. This alignment revealed a marked difference between the HLA-G molecule and other MHC class I molecules. By mutating these residues to the equivalent classical MHC residues, the HLA-G molecule regained an ability of interacting with KIR inhibitory receptors found on NK cells derived either from peripheral blood or from the decidua. Functional NK killing assays further substantiated the binding results. Furthermore, double immunofluorescent staining of placental sections revealed that while the conformed form of HLA-G was expressed in all extravillous trophoblasts, the free heavy chain form of HLA-G was expressed in more distal cells of the column, the invasion front. Overall we suggest that HLA-G protein evolved to interact with only some of the NK inhibitory receptors thus allowing a control of inhibition, while permitting appropriate NK cell cytokine and growth factor production necessary for a viable maternal fetal interface.

  11. Electronic level alignment at the deeply buried absorber/Mo interface in chalcopyrite-based thin film solar cells

    Science.gov (United States)

    Bär, M.; Nishiwaki, S.; Weinhardt, L.; Pookpanratana, S.; Shafarman, W. N.; Heske, C.

    2008-07-01

    We have investigated the electronic structure of the absorber/back contact interface for S-free [Cu(In ,Ga)Se2 ("CIGSe")] and S-containing [Cu(In ,Ga)(S,Se)2 ("CIGSSe")] chalcopyrites with direct and inverse photoemission. Comparison of the electronic levels of the cleavage planes reveals a pronounced cliff in the conduction band at the CIG(S )Se/Mo interface. For the valence band, we find a flat alignment and a small spike for the CIGSe- and CIGSSe-based structures, respectively.

  12. Establishment and characterization of a differentiated epithelial cell culture model derived from the porcine cervix uteri

    Directory of Open Access Journals (Sweden)

    Miessen Katrin

    2012-03-01

    Full Text Available Abstract Background Cervical uterine epithelial cells maintain a physiological and pathogen-free milieu in the female mammalian reproductive tract and are involved in sperm-epithelium interaction. Easily accessible, differentiated model systems of the cervical epithelium are not yet available to elucidate the underlying molecular mechanisms within these highly specialized cells. Therefore, the aim of the study was to establish a cell culture of the porcine cervical epithelium representing in vivo-like properties of the tissue. Results We tested different isolation methods and culture conditions and validated purity of the cultured cells by immunohistochemistry against keratins. We could reproducibly culture pure epithelial cells from cervical tissue explants. Based on a morphology score and the WST-1 Proliferation Assay, we optimized the growth medium composition. Primary porcine cervical cells performed best in conditioned Ham's F-12, containing 10% FCS, EGF and insulin. After cultivation in an air-liquid interface for three weeks, the cells showed a discontinuously multilayered phenotype. Finally, differentiation was validated via immunohistochemistry against beta catenin. Mucopolysaccharide production could be shown via alcian blue staining. Conclusions We provide the first suitable protocol to establish a differentiated porcine epithelial model of the cervix uteri, based on easily accessible cells using slaughterhouse material.

  13. 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.

  14. 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

  15. Porcine reproductive and respiratory syndrome virus infection is associated with an increased number of Sn-positive and CD8-positive cells in the maternal-fetal interface.

    Science.gov (United States)

    Karniychuk, U U; De Spiegelaere, W; Nauwynck, H J

    2013-09-01

    It is already known that porcine reproductive and respiratory syndrome virus (PRRSV) infection in lungs changes a local cell pattern and cytokine profile. However, there is no information about cellular and immunological events upon PRRSV infection in the maternal-fetal interface yet. The altered number and/or function of macrophages and NK cells in the maternal-fetal interface during infection may have a functional importance for virus replication. In addition, local cellular and immunological disbalance may also disrupt fragile homeostasis and contribute to the PRRSV-related reproductive disorders. Sialoadhesin (Sn)-positive macrophages are target cells for PRRSV and Sn overexpression has been observed upon chronic inflammatory and infectious diseases. It is also known that mouse Sn-positive macrophages in lymph nodes are able to closely interact with and activate NK cells in response to viral particles. Therefore, the main purpose of the present study was to examine if PRRSV infection is associated with altered Sn expression on endometrial and placental macrophages. In addition, CD8-positive cells (porcine endometrial NK cells were previously described as CD8(+)CD3(-) cells) were localized and quantified in the PRRSV-positive and control tissues. Tissue samples were obtained from three PRRSV-inoculated and three non-inoculated control sows at 100 days of gestation. Real-time RT-PCR showed a clear upregulation of Sn mRNA expression in the PRRSV-positive endometrium/placenta (pPRRSV-inoculated sows had a significantly higher number of Sn-positive macrophages in the endometrium and placenta due to de novo Sn expression on local CD163-positive macrophages. Along with the increased number of Sn-positive macrophages an increased number of CD8-positive cells, which were mostly CD3-negative, was observed in the PRRSV-positive endometrium. The effects of the observed cellular changes on virus replication and potential contribution to placental damage and reproductive

  16. The interaction of eugenol with cell membrane models at the air-water interface is modulated by the lipid monolayer composition.

    Science.gov (United States)

    Gonçalves, Giulia E G; de Souza, Fernanda S; Lago, João Henrique G; Caseli, Luciano

    2015-12-01

    Eugenol, a natural phenylpropanoid derivative with possible action in biological surfaces as microbicide, anesthetic and antioxidant, was incorporated in lipid monolayers of selected lipids at the air-water interface, representing cell membrane models. Interaction of eugenol with the lipids dipalmitoylphosphatidylcholine (DPPC), dioctadecyldimethylammonium bromide (DODAB), and dipalmitoylphosphatidylserine (DPPS) could be inferred by means of surface pressure-area isotherms and Polarization-Modulation Reflection-Absorption Spectroscopy. The interaction showed different effects on the different lipids. A higher monolayer expansion was observed for DPPS and DODAB, while more significant effects on the polar groups of the lipids were observed for DPPS and DPPC. These results pointed to the fact that the interaction of eugenol with lipid monolayers at the air-water interface is modulated by the lipid composition, which may be important to comprehend at the molecular level the interaction of this drug with biological surfaces.

  17. 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.

  18. Testing Interfaces

    DEFF Research Database (Denmark)

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

    1999-01-01

    The wide use of solid insulating materials combinations in combinations has introduced problems in the interfaces between components. The most common insulating materials are cross-linked polyethylene (XLPE), silicone rubber (SIR) and ethylene-propylene rubbers (EPR). Assemblies of these materials...

  19. Gesture Interfaces

    NARCIS (Netherlands)

    Fikkert, F.W.

    2007-01-01

    Take away mouse and keyboard. Now, how do you interact with a computer? Especially one that has a display that is the size of an entire wall. One possibility is through gesture interfaces. Remember Minority Report? Cool stuff, but that was already five years ago.. So, what is already possible now an

  20. Manufacturing Interfaces

    NARCIS (Netherlands)

    Houten, van F.J.A.M.

    1992-01-01

    The paper identifies the changing needs and requirements with respect to the interfacing of manufacturing functions. It considers the manufacturing system, its components and their relationships from the technological and logistic point of view, against the background of concurrent engineering. Desi

  1. XPS characterization of different thermal treatments in the ITO-Si interface of a carbonate-textured monocrystalline silicon solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Montesdeoca-Santana, A.; Jimenez-Rodriguez, E.; Marrero, N.; Gonzalez-Diaz, B. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez, 2, 38206 La Laguna, S/C de Tenerife (Spain); Borchert, D. [Institut fuer Solare Energiesysteme, Fraunhofer Institut, Auf der Reihe 2, 45884 Gelsenkirchen (Germany); Guerrero-Lemus, R., E-mail: rglemus@ull.e [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez, 2, 38206 La Laguna, S/C de Tenerife (Spain); Fundacion de Estudios de Economia Aplicada, Catedra Focus-Abengoa, Jorge Juan 46, 28001 Madrid (Spain)

    2010-02-15

    In this work we have applied the X-ray photoelectron spectroscopy (XPS) in depth to study, for the first time, the influence of different thermal treatments in the ITO-Si interface of a monocrystalline Si-based solar cell where the Si surface is carbonate-textured and covered by an ITO sputtered layer. The efficiency of the solar cells significantly increases when thermal treatments are applied just after the ITO deposition. The efficiency is also dependent on the characteristics of the pyramidal relief of the silicon surface previously obtained by immersion of the Si wafers in a sodium carbonate/bicarbonate solution. An efficiency of 15.5% has been obtained with an optimized texturization of the silicon substrates and an annealing treatment of the solar cells at 400 deg. C just after the ITO deposition.

  2. 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.

  3. Interaction of oral bacteria with gingival epithelial cell multilayers.

    Science.gov (United States)

    Dickinson, B C; Moffatt, C E; Hagerty, D; Whitmore, S E; Brown, T A; Graves, D T; Lamont, R J

    2011-06-01

    Primary gingival epithelial cells were cultured in multilayers as a model for the study of interactions with oral bacteria associated with health and periodontal disease. Multilayers maintained at an air-liquid interface in low-calcium medium displayed differentiation and cytokeratin properties characteristic of junctional epithelium. Multilayers were infected with fluorescently labeled Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum or Streptococcus gordonii, and bacterial association was determined by confocal microscopy and quantitative image analysis. Porphyromonas gingivalis invaded intracellularly and spread from cell to cell; A. actinomycetemcomitans and F. nucleatum remained extracellular and showed intercellular movement through the multilayer; whereas S. gordonii remained extracellular and predominantly associated with the superficial cell layer. None of the bacterial species disrupted barrier function as measured by transepithelial electrical resistance. P. gingivalis did not elicit secretion of proinflammatory cytokines. However, A. actinomycetemcomitans and S. gordonii induced interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-6 and IL-8 secretion; and F. nucleatum stimulated production of IL-1β and TNF-α. Aggregatibacter actinomycetemcomitans, F. nucleatum and S. gordonii, but not P. gingivalis, increased levels of apoptosis after 24 h infection. The results indicate that the organisms with pathogenic potential were able to traverse the epithelium, whereas the commensal bacteria did not. In addition, distinct host responses characterized the interaction between the junctional epithelium and oral bacteria.

  4. 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.

  5. Fast Crystallization and Improved Stability of Perovskite Solar Cells with Zn2SnO4 Electron Transporting Layer: Interface Matters.

    Science.gov (United States)

    Bera, Ashok; Sheikh, Arif D; Haque, Md Azimul; Bose, Riya; Alarousu, Erkki; Mohammed, Omar F; Wu, Tom

    2015-12-30

    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 crystallized 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.

  6. Investigating the role of microbes in mineral weathering: nanometre-scale characterisation of the cell-mineral interface using FIB and TEM.

    Science.gov (United States)

    Ward, Michael B; Kapitulčinová, Dana; Brown, Andrew P; Heard, Peter J; Cherns, David; Cockell, Charles S; Hallam, Keith R; Ragnarsdóttir, K Vala

    2013-04-01

    Focused ion beam (FIB) sample preparation in combination with subsequent transmission electron microscopy (TEM) analysis are powerful tools for nanometre-scale examination of the cell-mineral interface in bio-geological samples. In this study, we used FIB-TEM to investigate the interaction between a cyanobacterium (Hassallia byssoidea) and a common sheet silicate mineral (biotite) following a laboratory-based bioweathering, incubation experiment. We discuss the FIB preparation of cross-sections of the cell mineral interface for TEM investigation. We also establish an electron fluence threshold (at 200keV) in biotite for the transition from scanning (S)TEM electron beam induced contamination build up on the surface of biotite thin sections to mass loss, or hole-drilling within the sections. Working below this threshold fluence nanometre-scale structural and elemental information has been obtained from biotite directly underneath cyanobacterial cells incubated on the biotite for 3 months. No physical alteration of the biotite was detected by TEM imaging and diffraction with little or no elemental alteration detected by STEM-energy dispersive X-ray (EDX) elemental line-scanning or by energy filtered TEM (EF-TEM) jump ratio elemental mapping. As such we present evidence that the cyanobacterial strain of H. byssoidea did not cause any measurable alteration of biotite, within the resolution limits of the analysis techniques used, after 3 months of incubation on its surface.

  7. 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.

  8. A generalized crystal-cutting method for modeling arbitrarily oriented crystals in 3D periodic simulation cells with applications to crystal-crystal interfaces

    Science.gov (United States)

    Kroonblawd, Matthew P.; Mathew, Nithin; Jiang, Shan; Sewell, Thomas D.

    2016-10-01

    A Generalized Crystal-Cutting Method (GCCM) is developed that automates construction of three-dimensionally periodic simulation cells containing arbitrarily oriented single crystals and thin films, two-dimensionally (2D) infinite crystal-crystal homophase and heterophase interfaces, and nanostructures with intrinsic N-fold interfaces. The GCCM is based on a simple mathematical formalism that facilitates easy definition of constraints on cut crystal geometries. The method preserves the translational symmetry of all Bravais lattices and thus can be applied to any crystal described by such a lattice including complicated, low-symmetry molecular crystals. Implementations are presented with carefully articulated combinations of loop searches and constraints that drastically reduce computational complexity compared to simple loop searches. Orthorhombic representations of monoclinic and triclinic crystals found using the GCCM overcome some limitations in standard distributions of popular molecular dynamics software packages. Stability of grain boundaries in β-HMX was investigated using molecular dynamics and molecular statics simulations with 2D infinite crystal-crystal homophase interfaces created using the GCCM. The order of stabilities for the four grain boundaries studied is predicted to correlate with the relative prominence of particular crystal faces in lab-grown β-HMX crystals. We demonstrate how nanostructures can be constructed through simple constraints applied in the GCCM framework. Example GCCM constructions are shown that are relevant to some current problems in materials science, including shock sensitivity of explosives, layered electronic devices, and pharmaceuticals.

  9. In vitro investigation of a tissue-engineered cell-tendon complex mimicking the transitional architecture at the ligament-bone interface.

    Science.gov (United States)

    Wang, Zhibing; Zhang, Yuan; Zhu, Jie; Dong, Shiwu; Jiang, Tao; Zhou, Yue; Zhang, Xia

    2015-03-01

    Restoration of the transitional ligament-bone interface is critical for graft-bone integration. We postulated that an allogenic scaffold mimicking the fibrogenic, chondrogenic, and osteogenic transition gradients could physiologically promote ligament-bone incorporation. The aim of this study was to construct and characterize a composite tendon scaffold with a continuous and heterogeneous transition region mimicking a native ligament insertion site. Genetically modified heterogeneous cell populations were seeded within specific regions of decellularized rabbit Achilles tendons to fabricate a stratified scaffold containing three biofunctional regions supporting fibrogenesis, chondrogenesis, and osteogenesis. The observed morphology, architecture, cytocompatibility, and biomechanics of the scaffolds demonstrated their improved bio-physico-chemical properties. The formation of the transitional regions was augmented via enhanced delivery of two transcription factors, sex determining region Y-box 9 and runt-related transcription factor 2, which also triggered early up-regulated expression of cartilage- and bone-relevant markers, according to quantitative PCR and immunoblot analyses. Gradient tissue-specific matrix formation was also confirmed within the predesignated regions via histological staining and immunofluorescence assays. These results suggest that a transitional interface could be replicated on an engineered tendon through stratified tissue integration. The scaffold offers the advantages of a multitissue transition involving controlled cellular interactions and matrix heterogeneity, which can be applied for the regeneration of the ligament-bone interface.

  10. Development and analysis of Cu-doped ZnTe for use as a back contact interface for CdS/CdTe solar cells

    Science.gov (United States)

    Gessert, T. A.; Coutts, T. J.

    1994-06-01

    It is well known that the losses associated with the back contact of typical CdS/CdTe solar cell devices can be a substantial part of the total external loss. Previous modeling has indicated that these losses will be significant, unless the value of specific contact resistance (rc) at this interface is reduced to ˜0.10 Ω-cm2 or less. Although several studies have inferred values of rc near this level, few have attempted to measure directly the value of rc as a function of various processing conditions. One reason for this situation is the difficulty in fabricating the appropriate patterns for direct analysis of rc. In the following paper, initial characterization studies of sputter-deposited, Cu-doped ZnTe are documented. Additionally, recent attempts to measure directly the contact resistance associated with the two interfaces of the Ni/ZnTe/CdTe contact stack, are presented and discussed. Preliminary testing of these processes has been conducted using sputter-deposited test structures representing the individual interfaces of a typical Ni/ZnTe/CdTe contact stack. Contact resistance analysis of these structures has allowed for the estimation of rc suggesting that, for the conditions studied, the contact stack appears to meet the criterion of yielding an rc value <0.1 Ω-cm2.

  11. 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

  12. Interface learning

    DEFF Research Database (Denmark)

    Thorhauge, Sally

    2014-01-01

    for 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...... 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...

  13. Mo/Cu(In, Ga)Se{sub 2} back interface chemical and optical properties for ultrathin CIGSe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Erfurth, F.; Jehl, Z. [Institut de Recherche et Developpement sur l' Energie Photovoltaieque IRDEP (EDF/CNRS/Chimie-ParisTech UMR 7174), 6 quai Watier, 78401 Chatou (France); Bouttemy, M. [ILV - UMR 8180, Universite de Versailles St Quentin, 45 Av. des Etats Unis, 78035 Versailles (France); Dahan, N. [Institut d' Optique, CNRS, Campus Polytechnique, RD 128, 91127 Palaiseau Cedex (France); Tran-Van, P.; Gerard, I.; Etcheberry, A. [ILV - UMR 8180, Universite de Versailles St Quentin, 45 Av. des Etats Unis, 78035 Versailles (France); Greffet, J.-J. [Institut d' Optique, CNRS, Campus Polytechnique, RD 128, 91127 Palaiseau Cedex (France); Powalla, M. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung (ZSW), Industriestr. 6, 70565 Stuttgart (Germany); Voorwinden, G. [Wuerth Elektronik Research GmbH, Industriestr. 4, 70565 Stuttgart (Germany); Lincot, D.; Guillemoles, J.F. [Institut de Recherche et Developpement sur l' Energie Photovoltaieque IRDEP (EDF/CNRS/Chimie-ParisTech UMR 7174), 6 quai Watier, 78401 Chatou (France); Naghavi, N., E-mail: negar.naghavi@edf.fr [Institut de Recherche et Developpement sur l' Energie Photovoltaieque IRDEP (EDF/CNRS/Chimie-ParisTech UMR 7174), 6 quai Watier, 78401 Chatou (France)

    2012-01-15

    Chemical and optical properties of the interface between a coevaporated Cu(In,Ga)Se{sub 2} (CIGSe) absorber thin film and the Mo back contact are investigated with the objective to reduce markedly the thickness of CIGSe layers from two microns down to about 100 nm. First a mechanical lift off technique allowed to separate Mo and CIGSe layers and perform X-ray photoelectron spectroscopy (XPS) and elipsometry studies on as prepared surfaces. On the Mo side small amounts of In and Ga are observed together with the formation of an MoSe{sub 2} layer. There is no evidence of the presence of Cu. On the opposite CIGSe side a clear depletion of Cu together with an enrichment of Ga is evidenced. There is no evidence of Mo. Optical reflectivity of the interface CIGSe/Mo is studied by ellipsometry showing a low reflectivity of the interface attributed to the formation of MoSe{sub 2} layer. The enhance light absorption in ultrathin absorbers using alternative, highly reflective back contacts are finally discussed.

  14. Mo/Cu(In, Ga)Se 2 back interface chemical and optical properties for ultrathin CIGSe solar cells

    Science.gov (United States)

    Erfurth, F.; Jehl, Z.; Bouttemy, M.; Dahan, N.; Tran-Van, P.; Gerard, I.; Etcheberry, A.; Greffet, J.-J.; Powalla, M.; Voorwinden, G.; Lincot, D.; Guillemoles, J. F.; Naghavi, N.

    2012-01-01

    Chemical and optical properties of the interface between a coevaporated Cu(In,Ga)Se2 (CIGSe) absorber thin film and the Mo back contact are investigated with the objective to reduce markedly the thickness of CIGSe layers from two microns down to about 100 nm. First a mechanical lift off technique allowed to separate Mo and CIGSe layers and perform X-ray photoelectron spectroscopy (XPS) and elipsometry studies on as prepared surfaces. On the Mo side small amounts of In and Ga are observed together with the formation of an MoSe2 layer. There is no evidence of the presence of Cu. On the opposite CIGSe side a clear depletion of Cu together with an enrichment of Ga is evidenced. There is no evidence of Mo. Optical reflectivity of the interface CIGSe/Mo is studied by ellipsometry showing a low reflectivity of the interface attributed to the formation of MoSe2 layer. The enhance light absorption in ultrathin absorbers using alternative, highly reflective back contacts are finally discussed.

  15. Museets interface

    DEFF Research Database (Denmark)

    Pold, Søren

    2007-01-01

    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 i...

  16. Artificial Skin – Culturing of Different Skin Cell Lines for Generating an Artificial Skin Substitute on Cross-Weaved Spider Silk Fibres

    Science.gov (United States)

    Reimers, Kerstin; Kuhbier, Joern W.; Schäfer-Nolte, Franziska; Allmeling, Christina; Kasper, Cornelia; Vogt, Peter M.

    2011-01-01

    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. PMID:21814557

  17. 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.

  18. 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.

  19. SPLUNC1 regulation in airway epithelial cells: role of toll-like receptor 2 signaling

    Directory of Open Access Journals (Sweden)

    Smith Sean

    2010-11-01

    Full Text Available Abstract Background Respiratory infections including Mycoplasma pneumoniae (Mp contribute to various chronic lung diseases. We have shown that mouse short palate, lung, and nasal epithelium clone 1 (SPLUNC1 protein was able to inhibit Mp growth. Further, airway epithelial cells increased SPLUNC1 expression upon Mp infection. However, the mechanisms underlying SPLUNC1 regulation remain unknown. In the current study, we investigated if SPLUNC1 production following Mp infection is regulated through Toll-like receptor 2 (TLR2 signaling. Methods Airway epithelial cell cultures were utilized to reveal the contribution of TLR2 signaling including NF-κB to SPLUNC1 production upon bacterial infection and TLR2 agonist stimulation. Results Mp and TLR2 agonist Pam3CSK4 increased SPLUNC1 expression in tracheal epithelial cells from wild type, but not TLR2-/- BALB/c mice. RNA interference (short-hairpin RNA of TLR2 in normal human bronchial epithelial cells under air-liquid interface cultures significantly reduced SPLUNC1 levels in Mp-infected or Pam3CSK4-treated cells. Inhibition and activation of NF-κB pathway decreased and increased SPLUNC1 production in airway epithelial cells, respectively. Conclusions Our data for the first time suggest that airway epithelial TLR2 signaling is pivotal in mycoplasma-induced SPLUNC1 production, thus improving our understanding of the aberrant SPLUNC1 expression in airways of patients suffering from chronic lung diseases with bacterial infections.

  20. 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.

  1. Characterization of the TiO2/dye/electrolyte interfaces in dye-sensitized solar cells by means of a titania-binding nitroxide.

    Science.gov (United States)

    Fattori, Alberto; Cangiotti, Michela; Fiorani, Luigi; Lucchi, Susanna; Ottaviani, Maria Francesca

    2014-11-18

    Dye-sensitized solar cells (DSSCs) have been characterized in several literature examples by using relatively complex methods and/or modified DSSC conditions with respect to the usual working ones. In this study, we propose a method for the investigation of the interfaces TiO2/dye/electrolyte in a DSSC at its usual working conditions. This method implies the use of a computer-aided analysis of the electron paramagnetic resonance (EPR) spectra of the spin probe 4-carboxy-2,2,6,6-tetramethylpiperidine 1-oxyl (4-carboxy-TEMPO, indicated as 4-cT). This probe well-mimics the dyes in their interactions with TiO2 surface, but does not perturb dye adsorption onto TiO2 surface, as verified by UV-vis measurements. First, we investigated the interacting ability toward 4-cT of commercially available TiO2 used for assembling the DSSC. It was found that interactions are modulated by the different distribution of interacting sites at the solid surface and powder aggregation. Further, experiments on 4-cT were carried out in the presence of a series of other molecules coded as N3, N719, and D149, which are commonly used as dyes in DSSCs. Then, the effect of solutions added to the electrodes was investigated. On the basis of the interactions occurring at the TiO2/dye/electrolyte interfaces, we selected the ingredients of the DSSCs. Electrical and EPR characterizations of these DSSCs miniaturized to enter the EPR cavity, together with time-dependent laser-light on-off experiments, were carried out, which demonstrated the ability of the EPR analysis to monitor the types and strengths of the interactions occurring at the cell's different interfaces. This method using the standard continuous wave EPR technique at room temperature may be profitably used to characterize the quality and performances of a DSSC.

  2. Mechanism of Action of Thymol on Cell Membranes Investigated through Lipid Langmuir Monolayers at the Air-Water Interface and Molecular Simulation.

    Science.gov (United States)

    Ferreira, João Victor N; Capello, Tabata M; Siqueira, Leonardo J A; Lago, João Henrique G; Caseli, Luciano

    2016-04-05

    A major challenge in the design of biocidal drugs is to identify compounds with potential action on microorganisms and to understand at the molecular level their mechanism of action. In this study, thymol, a monoterpenoid found in the oil of leaves of Lippia sidoides with possible action in biological surfaces, was incorporated in lipid monolayers at the air-water interface that represented cell membrane models. The interaction of thymol with dipalmitoylphosphatidylcholine (DPPC) at the air-water interface was investigated by means of surface pressure-area isotherms, Brewster angle microscopy (BAM), polarization-modulation reflection-absorption spectroscopy (PM-IRRAS), and molecular dynamics simulation. Thymol expands DPPC monolayers, decreases their surface elasticity, and changes the morphology of the lipid monolayer, which evidence the incorporation of this compound in the lipid Langmuir film. Such incorporation could be corroborated by PM-IRRAS since some specific bands for DPPC were changed upon thymol incorporation. Furthermore, potential of mean force obtained by molecular dynamics simulations indicates that the most stable position of the drug along the lipid film is near the hydrophobic regions of DPPC. These results may be useful to understand the interaction between thymol and cell membranes during biochemical phenomena, which may be associated with its pharmaceutical properties at the molecular level.

  3. The influence of annealing temperature on the interface and photovoltaic properties of CdS/CdSe quantum dots sensitized ZnO nanorods solar cells.

    Science.gov (United States)

    Qiu, Xiaofeng; Chen, Ling; Gong, Haibo; Zhu, Min; Han, Jun; Zi, Min; Yang, Xiaopeng; Ji, Changjian; Cao, Bingqiang

    2014-09-15

    Arrays of ZnO/CdS/CdSe core/shell nanocables with different annealing temperatures have been investigated for CdS/CdSe quantum dots sensitized solar cells (QDSSCs). CdS/CdSe quantum dots were synthesized on the surface of ZnO nanorods that serve as the scaffold via a simple ion-exchange approach. The uniform microstructure was verified by scanning electron microscope and transmission electron microscope. UV-Visible absorption spectrum and Raman spectroscopy analysis indicated noticeable influence of annealing temperature on the interface structural and optical properties of the CdS/CdSe layers. Particularly, the relationship between annealing temperatures and photovoltaic performance of the corresponding QDSSCs was investigated employing photovoltaic conversion, quantum efficiency and electrochemical impedance spectra. It is demonstrated that higher cell efficiency can be obtained by optimizing the annealing temperature through extending the photoresponse range and improving QD layer crystal quality.

  4. 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 were...

  5. 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.

  6. 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.

  7. Interface properties of (Cd,Zn)S/CuInSe/sub 2/ single-crystal solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Elfotouh, F.A.; Kazmerski, L.L.; Coutts, T.J.; Matson, R.J.; Asher, S.E.; Nelson, A.J.; Swartzlander-Franz, A.B.

    1989-05-01

    Metal contacts to p-type CuInSe/sub 2/ and heterojunctions of the form n-(CdZn)S/p-CuInSe/sub 2/ have been prepared, to investigate the electrical behavior and chemical composition of the resulting interfaces and to correlate the results with the composition and corresponding electrical properties of CuInSe/sub 2/ . The results indicate that the observed variability of the back contacts and front junctions of different CuInSe/sub 2/ samples can be attributed to the variable initial equilibrium concentration of the intrinsic defect states which dominate the crystals. The type and concentration of the dominant defects can be changed by thermal treatments and by interface induced effects due to the junction electric field and the chemical potential gradients. Diffusion into or out of the CuInSe/sub 2/ crystals was not detected. More over, no composition or other chemical variation due to the deposition of the sulfide layer was observed.

  8. 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

    2016-04-23

    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.

  9. A model of human nasal epithelial cells adapted for direct and repeated exposure to airborne pollutants.

    Science.gov (United States)

    Bardet, Gaëlle; Achard, Sophie; Loret, Thomas; Desauziers, Valérie; Momas, Isabelle; Seta, Nathalie

    2014-08-17

    Airway epithelium lining the nasal cavity plays a pivotal role in respiratory tract defense and protection mechanisms. Air pollution induces alterations linked to airway diseases such as asthma. Only very few in vitro studies to date have succeeded in reproducing physiological conditions relevant to cellular type and chronic atmospheric pollution exposure. We therefore, set up an in vitro model of human Airway Epithelial Cells of Nasal origin (hAECN) close to real human cell functionality, specifically adapted to study the biological effects of exposure to indoor gaseous pollution at the environmental level. hAECN were exposed under air-liquid interface, one, two, or three-times at 24 h intervals for 1 h, to air or formaldehyde (200 μg/m(3)), an indoor air gaseous pollutant. All experiments were ended at day 4, when both cellular viability and cytokine production were assessed. Optimal adherence and confluence of cells were obtained 96 h after cell seeding onto collagen IV-precoated insert. Direct and repeated exposure to formaldehyde did not produce any cellular damage or IL-6 production change, although weak lower IL-8 production was observed only after the third exposure. Our model is significantly better than previous ones due to cell type and the repeated exposure protocol.

  10. A cell-based computational modeling approach for developing site-directed molecular probes.

    Directory of Open Access Journals (Sweden)

    Jing-Yu Yu

    Full Text Available Modeling the local absorption and retention patterns of membrane-permeant small molecules in a cellular context could facilitate development of site-directed chemical agents for bioimaging or therapeutic applications. Here, we present an integrative approach to this problem, combining in silico computational models, in vitro cell based assays and in vivo biodistribution studies. To target small molecule probes to the epithelial cells of the upper airways, a multiscale computational model of the lung was first used as a screening tool, in silico. Following virtual screening, cell monolayers differentiated on microfabricated pore arrays and multilayer cultures of primary human bronchial epithelial cells differentiated in an air-liquid interface were used to test the local absorption and intracellular retention patterns of selected probes, in vitro. Lastly, experiments involving visualization of bioimaging probe distribution in the lungs after local and systemic administration were used to test the relevance of computational models and cell-based assays, in vivo. The results of in vivo experiments were consistent with the results of in silico simulations, indicating that mitochondrial accumulation of membrane permeant, hydrophilic cations can be used to maximize local exposure and retention, specifically in the upper airways after intratracheal administration.

  11. Effect of surface active compounds on growth and adhesion of anchorage-dependent animal cells at liquid/liquid interface; Eki/ekikaimen ni okeru fuchaku izonsei dobutsu saibo no zoshoku oyobi fuchaku ni taisuru kaimen kassei busshitsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, Y.; Oshima, T.; Sato, M. [Gunma Univ., Kiryu (Japan). Faculty of Technology

    1998-03-01

    A cell cultivation using a liquid/liquid (culture medium/fluorocarbon) interface has been practiced as a novel culturing method for anchorage-dependent animal cells, and it is known that cell adhesion at the interface is dependent on the contaminants contained in the hydrophobic liquid. Substances effective for the adhesion and growth of cells are investigated using various surfactants. As a result of comparison of ionic and nonionic surfactants, cell adhesion is observed when ionic surfactant is used, indicating the importance of the electric charge of surfactant. Cell growth is better when ionic surfactant is added to fluorocarbon than when surfactant is added to the culture medium. The cell growth using fluorocarbon added with pentafluorobenzoyl chloride and perfluorooctanoyl chloride is similar to that of culturing using polystyrene, and the importance of surfactant addition to fluorocarbon is indicated. 7 refs., 4 figs.

  12. Gene expression profiling of monkeypox virus-infected cells reveals novel interfaces for host-virus interactions

    Directory of Open Access Journals (Sweden)

    Ichou Mohamed

    2010-07-01

    Full Text Available Abstract Monkeypox virus (MPV is a zoonotic Orthopoxvirus and a potential biothreat agent that causes human disease with varying morbidity and mortality. Members of the Orthopoxvirus genus have been shown to suppress antiviral cell defenses, exploit host cell machinery, and delay infection-induced cell death. However, a comprehensive study of all host genes and virus-targeted host networks during infection is lacking. To better understand viral strategies adopted in manipulating routine host biology on global scale, we investigated the effect of MPV infection on Macaca mulatta kidney epithelial cells (MK2 using GeneChip rhesus macaque genome microarrays. Functional analysis of genes differentially expressed at 3 and 7 hours post infection showed distinctive regulation of canonical pathways and networks. While the majority of modulated histone-encoding genes exhibited sharp copy number increases, many of its transcription regulators were substantially suppressed; suggesting involvement of unknown viral factors in host histone expression. In agreement with known viral dependence on actin in motility, egress, and infection of adjacent cells, our results showed extensive regulation of genes usually involved in controlling actin expression dynamics. Similarly, a substantial ratio of genes contributing to cell cycle checkpoints exhibited concerted regulation that favors cell cycle progression in G1, S, G2 phases, but arrest cells in G2 phase and inhibits entry into mitosis. Moreover, the data showed that large number of infection-regulated genes is involved in molecular mechanisms characteristic of cancer canonical pathways. Interestingly, ten ion channels and transporters showed progressive suppression during the course of infection. Although the outcome of this unusual channel expression on cell osmotic homeostasis remains unknown, instability of cell osmotic balance and membrane potential has been implicated in intracellular pathogens egress. Our

  13. Applications of cell-free protein synthesis in synthetic biology: Interfacing bio-machinery with synthetic environments.

    Science.gov (United States)

    Lee, Kyung-Ho; Kim, Dong-Myung

    2013-11-01

    Synthetic biology is built on the synthesis, engineering, and assembly of biological parts. Proteins are the first components considered for the construction of systems with designed biological functions because proteins carry out most of the biological functions and chemical reactions inside cells. Protein synthesis is considered to comprise the most basic levels of the hierarchical structure of synthetic biology. Cell-free protein synthesis has emerged as a powerful technology that can potentially transform the concept of bioprocesses. With the ability to harness the synthetic power of biology without many of the constraints of cell-based systems, cell-free protein synthesis enables the rapid creation of protein molecules from diverse sources of genetic information. Cell-free protein synthesis is virtually free from the intrinsic constraints of cell-based methods and offers greater flexibility in system design and manipulability of biological synthetic machinery. Among its potential applications, cell-free protein synthesis can be combined with various man-made devices for rapid functional analysis of genomic sequences. This review covers recent efforts to integrate cell-free protein synthesis with various reaction devices and analytical platforms.

  14. Airborne acrolein induces keratin-8 (Ser-73) hyperphosphorylation and intermediate filament ubiquitination in bronchiolar lung cell monolayers.

    Science.gov (United States)

    Burcham, Philip C; Raso, Albert; Henry, Peter J

    2014-05-07

    The combustion product acrolein is a key mediator of pulmonary edema in victims of smoke inhalation injury. Since studying acrolein toxicity in conventional in vitro systems is complicated by reactivity with nucleophilic culture media constituents, we explored an exposure system which delivers airborne acrolein directly to lung cell monolayers at the air-liquid interface. Calu-3 lung adenocarcinoma cells were maintained on membrane inserts such that the basal surface was bathed in nucleophile-free media while the upper surface remained in contact with acrolein-containing air. Cells were exposed to airborne acrolein for 30 min before they were allowed to recover in fresh media, with cell sampling at defined time points to allow evaluation of toxicity and protein damage. After prior exposure to acrolein, cell ATP levels remained close to controls for 4h but decreased in an exposure-dependent manner by 24h. A loss of transepithelial electrical resistance and increased permeability to fluorescein isothiocyanate-labeled dextran preceded ATP loss. Use of antibody arrays to monitor protein expression in exposed monolayers identified strong upregulation of phospho-keratin-8 (Ser(73)) as an early consequence of acrolein exposure. These changes were accompanied by chemical damage to keratin-8 and other intermediate filament family members, while acrolein exposure also resulted in controlled ubiquitination of high mass proteins within the intermediate filament extracts. These findings confirm the usefulness of systems allowing delivery of airborne smoke constituents to lung cell monolayers during studies of the molecular basis for acute smoke intoxication injury.

  15. 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.

  16. 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.

  17. Characterization of a-SiNx:H layer. Bulk properties, interface with Si and solar cell efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Lamers, M.; Weeber, A. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands); Butler, K.; Harding, J. [University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Vullum, P.E. [SINTEF, Box 4760 Sluppen, 7465 Trondheim (Norway)

    2013-04-15

    In this paper two front-side a-SiNx:H layers that can be used in the solar cell industry are extensively characterized and related to solar cell efficiency. Variations in layer build up, atomic density, optical properties, bulk passivation and surface passivation are discussed. The build up of these two layers are considered against a background of over 80 SiNx:H layers. These layers differ in stoichiometry, atomic content, optical properties and surface passivation, as the refractive index is varied between 1.8 and 3.0. Additionally, comparable data output of different characterization equipment is discussed on validity. On solar cells, the effect of different layer build up is investigated and it is found that a wide process window is allowed for similar cell efficiencies regarding the optical transmission, bulk and surface passivation.

  18. Current Constriction at Electrode/Electrolyte Interfaces in Solid Oxide Cell Electrochemical Devices Calculated Via 3D Reconstructions

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Jørgensen, Peter Stanley; Graves, Christopher R.

    2016-01-01

    Electrochemical devices such as batteries, fuel cells, electrolysers, electrochemical reactors and electrochemical sensors are important technologies for the present and the future society. For further improvement or maturing of the various technologies it is important to understand, characterize...

  19. 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.

  20. 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.

  1. 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.

  2. Dung biomass smoke activates inflammatory signaling pathways in human small airway epithelial cells.

    Science.gov (United States)

    McCarthy, Claire E; Duffney, Parker F; Gelein, Robert; Thatcher, Thomas H; Elder, Alison; Phipps, Richard P; Sime, Patricia J

    2016-12-01

    Animal dung is a biomass fuel burned by vulnerable populations who cannot afford cleaner sources of energy, such as wood and gas, for cooking and heating their homes. Exposure to biomass smoke is the leading environmental risk for mortality, with over 4,000,000 deaths each year worldwide attributed to indoor air pollution from biomass smoke. Biomass smoke inhalation is epidemiologically associated with pulmonary diseases, including chronic obstructive pulmonary disease (COPD), lung cancer, and respiratory infections, especially in low and middle-income countries. Yet, few studies have examined the mechanisms of dung biomass smoke-induced inflammatory responses in human lung cells. Here, we tested the hypothesis that dung biomass smoke causes inflammatory responses in human lung cells through signaling pathways involved in acute and chronic lung inflammation. Primary human small airway epithelial cells (SAECs) were exposed to dung smoke at the air-liquid interface using a newly developed, automated, and reproducible dung biomass smoke generation system. The examination of inflammatory signaling showed that dung biomass smoke increased the production of several proinflammatory cytokines and enzymes in SAECs through activation of the activator protein (AP)-1 and arylhydrocarbon receptor (AhR) but not nuclear factor-κB (NF-κB) pathways. We propose that the inflammatory responses of lung cells exposed to dung biomass smoke contribute to the development of respiratory diseases.

  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 enhanced superconductivity in single unit-cell FeSe films on SrTiO3(110)

    Science.gov (United States)

    Wang, Lili

    The advent of enhanced superconductivity in FeSe/STO(001) has instigated great interests in other interfacial systems both experimentally and theoretically. To figure out the key role of substrate, STO(110) substrate is of great interest because it resembles STO(001) in high density subsurface oxygen vacancies but distinguishes itself by anisotropic in-plane lattice constants and dielectric constant. Here, we investigated molecular beam epitaxy growth of 1-UC FeSe films on STO(110) substrates and studied the superconducting properties by combined in-situ scanning tunneling spectroscopy (STS) and ex-situ transport measurement. By STS we observed a superconducting gap as large as 17 meV. Transport measurements on 1-UC FeSe/STO(110) capped with FeTe layers reveal superconductivity with an onset transition temperature (TC) of 31.6 K and an upper critical magnetic field of 30.2 T. We also find that TC can be further increased by an external electric field, but the effect is weaker than that on STO(001) substrate. Our study highlights the important roles of interface related charge transfer and electron-phonon coupling in the high temperature superconductivity of FeSe/STO. References: [1] Q. Y. Wang, et al., Chin. Phys. Lett., 29, 037402 (2012). [2] J. J. Lee, Nature 515, 245 (2014).

  5. 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.

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

    Science.gov (United States)

    Morton, Charles Oliver; Fliesser, Mirjam; Dittrich, Marcus; Mueller, Tobias; Bauer, Ruth; Kneitz, Susanne; Hope, William; Rogers, Thomas Richard; Einsele, Hermann; Loeffler, Juergen

    2014-01-01

    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.

  7. 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.

  8. INTERFACE STRUCTURE AND SCHOTTKY BARRIERS AT EPITAXIAL SI(111)/PB INTERFACES

    NARCIS (Netherlands)

    WEITERING, HH; HIBMA, T; HESLINGA, DR; KLAPWIJK, TM

    1991-01-01

    Two different epitaxial Si(111)/Pb interfaces can be prepared, i.e. a metastable interface with a (7 x 7) and a stable interface with an incommensurate but close to (square-root 3 x square-root 3)R30-degrees surface unit cell. Schottky barrier heights of diodes made by depositing thick Pb layers on

  9. Cell cycle arrest by prostaglandin A1 at the G1/S phase interface with up-regulation of oncogenes in S-49 cyc- cells

    Science.gov (United States)

    Hughes-Fulford, M.

    1994-01-01

    Our previous studies have implied that prostaglandins inhibit cell growth independent of cAMP. Recent reports, however, have suggested that prostaglandin arrest of the cell cycle may be mediated through protein kinase A. In this report, in order to eliminate the role of c-AMP in prostaglandin mediated cell cycle arrest, we use the -49 lymphoma variant (cyc-) cells that lack adenylate cyclase activity. We demonstrate that dimethyl prostaglandin A1 (dmPGA1) inhibits DNA synthesis and cell growth in cyc- cells. DNA synthesis is inhibited 42% by dmPGA1 (50 microM) despite the fact that this cell line lacks cellular components needed for cAMP generation. The ability to decrease DNA synthesis depends upon the specific prostaglandin structure with the most effective form possessing the alpha, beta unsaturated ketone ring. Dimethyl PGA1 is most effective in inhibiting DNA synthesis in cyc- cells, with prostaglandins PGE1 and PGB1 being less potent inhibitors of DNA synthesis. DmPGE2 caused a significant stimulation of DNA synthesis. S-49 cyc- variant cells exposed to (30-50 microns) dmPGA1, arrested in the G1 phase of the cell cycle within 24 h. This growth arrest was reversed when the prostaglandin was removed from the cultured cells; growth resumed within hours showing that this treatment is not toxic. The S-49 cyc- cells were chosen not only for their lack of adenylate cyclase activity, but also because their cell cycle has been extensively studied and time requirements for G1, S, G2, and M phases are known. Within hours after prostaglandin removal the cells resume active DNA synthesis, and cell number doubles within 15 h suggesting rapid entry into S-phase DNA synthesis from the G1 cell cycle block.(ABSTRACT TRUNCATED AT 250 WORDS).

  10. Molecular Dynamics Simulations of Interface Failure

    Science.gov (United States)

    Bachlechner, Martina E.; Cao, Deng; Leonard, Robert H.; Owens, Eli T.; Swan, Wm. Trevor, III; Ducatman, Samuel C.

    2007-03-01

    The mechanical integrity of silicon/silicon nitride interfaces is of great importance in their applications in micro electronics and solar cells. Large-scale molecular dynamics simulations are an excellent tool to study mechanical and structural failure of interfaces subjected to externally applied stresses and strains. When pulling the system parallel to the interface, cracks in silicon nitride and slip and pit formation in silicon are typical failure mechanisms. Hypervelocity impact perpendicular to the interface plane leads to structural transformation and delamination at the interface. Influence of system temperature, strain rate, impact velocity, and system size on type and characteristics of failure will be discussed.

  11. Solvation Dynamics of CO₂(g) by Monoethanolamine at the Gas-Liquid Interface: A Molecular Mechanics Approach.

    Science.gov (United States)

    Huang, I-Shou; Li, Jia-Jen; Tsai, Ming-Kang

    2016-12-23

    A classical force field approach was used to characterize the solvation dynamics of high-density CO₂(g) by monoethanolamine (MEA) at the air-liquid interface. Intra- and intermolecular CO₂ and MEA potentials were parameterized according to the energetics calculated at the MP2 and BLYP-D2 levels of theory. The thermodynamic properties of CO₂ and MEA, such as heat capacity and melting point, were consistently predicted using this classical potential. An approximate interfacial simulation for CO₂(g)/MEA(l) was performed to monitor the depletion of the CO₂(g) phase, which was influenced by amino and hydroxyl groups of MEA. There are more intramolecular hydrogen bond interactions notably identified in the interfacial simulation than the case of bulk MEA(l) simulation. The hydroxyl group of MEA was found to more actively approach CO₂ and overpower the amino group to interact with CO₂ at the air-liquid interface. With artificially reducing the dipole moment of the hydroxyl group, CO₂-amino group interaction was enhanced and suppressed CO₂(g) depletion. The hydroxyl group of MEA was concluded to play dual but contradictory roles for CO₂ capture.

  12. Gene Expression Profiling of Monkeypox Virus-Infected Cells Reveals Novel Interfaces for Host-Virus Interactions

    Science.gov (United States)

    2010-07-28

    translocation. J Biol Chem 2004, 279:8076-8083. 36. Earnshaw WC, Martins LM, Kaufmann SH: Mammalian caspases: structure, activation, substrates, and functions...Oncogene 2000, 19:5703-5711. 48. King KL, Cidlowski JA: Cell cycle regulation and apoptosis. Annu Rev Physiol 1998, 60:601-617. 49. Martin LG, Demers...regulation by Wnts and other signaling pathways. Adv Cancer Res 2002, 84:203-229. 59. Sakamoto K, Creamer BA, Triplett AA, Wagner KU: The Janus kinase 2 is

  13. 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.

  14. Serial block face-scanning electron microscopy: a tool for studying embryonic development at the cell-matrix interface.

    Science.gov (United States)

    Starborg, Tobias; Kadler, Karl E

    2015-03-01

    Studies of gene regulation, signaling pathways, and stem cell biology are contributing greatly to our understanding of early embryonic vertebrate development. However, much less is known about the events during the latter half of embryonic development, when tissues comprising mostly extracellular matrix (ECM) are formed. The matrix extends far beyond the boundaries of individual cells and is refractory to study by conventional biochemical and molecular techniques; thus major gaps exist in our knowledge of the formation and three-dimensional (3D) organization of the dense tissues that form the bulk of adult vertebrates. Serial block face-scanning electron microscopy (SBF-SEM) has the ability to image volumes of tissue containing numerous cells at a resolution sufficient to study the organization of the ECM. Furthermore, whereas light microscopy was once relatively straightforward and electron microscopy was performed in specialist laboratories, the tables are turned; SBF-SEM is relatively straightforward and is becoming routine in high-end resolution studies of embryonic structures in vivo. In this review, we discuss the emergence of SBF-SEM as a tool for studying embryonic vertebrate development.

  15. A new 3-D ray tracing method based on LTI using successive partitioning of cell interfaces and traveltime gradients

    Science.gov (United States)

    Zhang, Dong; Zhang, Ting-Ting; Zhang, Xiao-Lei; Yang, Yan; Hu, Ying; Qin, Qian-Qing

    2013-05-01

    We present a new method of three-dimensional (3-D) seismic ray tracing, based on an improvement to the linear traveltime interpolation (LTI) ray tracing algorithm. This new technique involves two separate steps. The first involves a forward calculation based on the LTI method and the dynamic successive partitioning scheme, which is applied to calculate traveltimes on cell boundaries and assumes a wavefront that expands from the source to all grid nodes in the computational domain. We locate several dynamic successive partition points on a cell's surface, the traveltimes of which can be calculated by linear interpolation between the vertices of the cell's boundary. The second is a backward step that uses Fermat's principle and the fact that the ray path is always perpendicular to the wavefront and follows the negative traveltime gradient. In this process, the first-arriving ray path can be traced from the receiver to the source along the negative traveltime gradient, which can be calculated by reconstructing the continuous traveltime field with cubic B-spline interpolation. This new 3-D ray tracing method is compared with the LTI method and the shortest path method (SPM) through a number of numerical experiments. These comparisons show obvious improvements to computed traveltimes and ray paths, both in precision and computational efficiency.

  16. 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.

  17. Development and interface/surface characterization of titanium dioxide and zinc oxide electron-collection interlayer materials for organic solar cells

    Science.gov (United States)

    Ou, Kai-Lin

    My research on metal oxide electron-harvesting interlayers for organic solar cells was focused as three interrelated projects in this dissertation: i) development of a chemical vapor deposition (CVD) system for TiO 2 film; ii) an electrochemical methodology to evaluate ZnO thin film charge (hole) blocking ability; iii) the effects of plasma modifications on sol-gel ZnO and sol-gel ZnO/organic (active layer) interfaces. In i), we showed that nanoscale (12-36 nm) CVD TiO2 film deposited at 210 oC obtains properties of conformal growth, superior hole blocking ability, stoichiometric metal to oxide ratio. The introduction of CVD TiO2 film as an electron transport layer into organic solar cell significantly improves its J-V characteristics. The optimum TiO2 thickness in the OPV device applications was found to be 24 nm with a high fill factor (0.58) and power conversion efficiency (3.7%) obtained. In ii), simple electrochemical methods, i.e., cyclic voltammetry, impedance spectroscopy have been used to evaluate sol-gel derived ZnO (sg-ZnO) and sputtered ZnO (sp-ZnO) porosity and pinhole density. We showed that sg-ZnO with high surface area porous structure allows the probe molecules and poly-thiophene (P3HT) thin layer to direct contact ITO substrate, whereas sp-ZnO with dense structural property efficiently eliminates these electroactivities. This electrochemical property difference also directly reflects on the device shunt resistance (Rp), where we observed larger leakage current for the devices using sg-ZnO than that of devices using sp-ZnO. In iii), we demonstrated low power radio frequency (RF) O2 and Ar plasma treatments have significant impacts on sg-ZnO near-surface chemical compositions, which in turn influence the onset potential of sg-ZnO electron injection and its energetic alignment with electron acceptors, e.g., C60. Using UPS, we found the presence of localized mid-gap states near the Fermi-level of sg-ZnO, which induces the most favorable band bending

  18. 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

  19. Room-Temperature Chemical Solution Treatment for Flexible ZnS(O,OH)/Cu(In,Ga)Se2 Solar Cell: Improvements in Interface Properties and Metastability.

    Science.gov (United States)

    Ho, Wei-Hao; Hsu, Chia-Hao; Yeh, Tzu-Hsuan; Chang, Yu-Han; Wei, Shih-Yuan; Lin, Tzu-Ying; Lai, Chih-Huang

    2016-03-01

    We demonstrate an effective room-temperature chemical solution treatment, by using thioacetamide (S treatment) or thioacetamide-InCl3 (In-S treatment) solution, on Cu(In,Ga)Se2 (CIGSe) surface to engineer the ZnS(O,OH)/CIGSe interface and junction quality, leading to enhanced efficiency and minimized metastability of flexible solar cells. The control device without treatment reveals a relatively low efficiency of 8.15%, which is significantly improved to 9.74% by In-S treatment, and 10.39% by S treatment. Results of X-ray photoelectron spectroscopy suggest that S is incorporated into CIGSe surface forming CIGSSe by S treatment, whereas a thin In-S layer is formed on CIGSe surface by In-S treatment with reduced amount of S diffusing into CIGSe. PL spectra and TRPL lifetime further reveal that S incorporation into CIGS surface may substitute the OSe and/or directly occupy the vacant anion site (VSe), resulting in the effective passivation of the recombination centers at CIGSe surface. Moreover, reducing the concentrations of VSe may thereby decrease the density of (VCu-VSe) acceptors, which can minimize the metastability of ZnS(O,OH)/CIGSe solar cells. With S treatment, the light soaking (LS) time of ZnS(O,OH)/CIGSe device is reduced approximately to one-half of control one. Our approach can be potentially applied for alternative Cd-free buffer layers to achieve high efficiency and low metastability.

  20. 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.

  1. Evaluation of layers of the rat airway epithelial cell line RL-65 for permeability screening of inhaled drug candidates.

    Science.gov (United States)

    Hutter, V; Hilgendorf, C; Cooper, A; Zann, V; Pritchard, D I; Bosquillon, C

    2012-09-29

    A rat respiratory epithelial cell culture system for in vitro prediction of drug pulmonary absorption is currently lacking. Such a model may however enhance the understanding of interspecies differences in inhaled drug pharmacokinetics by filling the gap between human in vitro and rat in/ex vivo drug permeability screens. The rat airway epithelial cell line RL-65 was cultured on Transwell inserts for up to 21 days at an air-liquid (AL) interface and cell layers were evaluated for their suitability as a drug permeability measurement tool. These layers were found to be morphologically representative of the bronchial/bronchiolar epithelium when cultured for 8 days in a defined serum-free medium. In addition, RL-65 layers developed epithelial barrier properties with a transepithelial electrical resistance (TEER) >300 Ω cm(2) and apparent (14)C-mannitol permeability (P(app)) values between 0.5-3.0 × 10(-6)cm/s; i.e., in the same range as established in vitro human bronchial epithelial absorption models. Expression of P-glycoprotein was confirmed by gene analysis and immunohistochemistry. Nevertheless, no vectorial transport of the established substrates (3)H-digoxin and Rhodamine123 was observed across the layers. Although preliminary, this study shows RL-65 cell layers have the potential to become a useful in vitro screening tool in the pre-clinical development of inhaled drug candidates.

  2. Silica nanoparticles are less toxic to human lung cells when deposited at the air–liquid interface compared to conventional submerged exposure

    Directory of Open Access Journals (Sweden)

    Alicja Panas

    2014-09-01

    Full Text Available Background: Investigations on adverse biological effects of nanoparticles (NPs in the lung by in vitro studies are usually performed under submerged conditions where NPs are suspended in cell culture media. However, the behaviour of nanoparticles such as agglomeration and sedimentation in such complex suspensions is difficult to control and hence the deposited cellular dose often remains unknown. Moreover, the cellular responses to NPs under submerged culture conditions might differ from those observed at physiological settings at the air–liquid interface.Results: In order to avoid problems because of an altered behaviour of the nanoparticles in cell culture medium and to mimic a more realistic situation relevant for inhalation, human A549 lung epithelial cells were exposed to aerosols at the air–liquid interphase (ALI by using the ALI deposition apparatus (ALIDA. The application of an electrostatic field allowed for particle deposition efficiencies that were higher by a factor of more than 20 compared to the unmodified VITROCELL deposition system. We studied two different amorphous silica nanoparticles (particles produced by flame synthesis and particles produced in suspension by the Stöber method. Aerosols with well-defined particle sizes and concentrations were generated by using a commercial electrospray generator or an atomizer. Only the electrospray method allowed for the generation of an aerosol containing monodisperse NPs. However, the deposited mass and surface dose of the particles was too low to induce cellular responses. Therefore, we generated the aerosol with an atomizer which supplied agglomerates and thus allowed a particle deposition with a three orders of magnitude higher mass and of surface doses on lung cells that induced significant biological effects. The deposited dose was estimated and independently validated by measurements using either transmission electron microscopy or, in case of labelled NPs, by fluorescence

  3. Electrical characterization of CIGSe solar cells metastability with Zn(S,O,OH)-ZnMgO interface buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    Serhan, J.; Darga, A.; Mencaraglia, D. [LGEP, UMR 8507 CNRS-SUPELEC-UPMC-Univ. Paris-Sud 11, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette Cedex (France); Djebbour, Z. [LGEP, UMR 8507 CNRS-SUPELEC-UPMC-Univ. Paris-Sud 11, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette Cedex (France); Department of Physics and Engineering Science, University of Versailles UVSQ, 45 Av. Des Etats Unis, 78035 Versailles (France); Naghavi, N.; Renou, G.; Lincot, D.; Guillemeoles, J.-F. [IRDEP, UMR 7174 CNRS-EDF-ENSCP, 6 Quai Watier-BP 49, 78401 Chatou Cedex (France)

    2010-11-15

    We have studied ZnO:Al/ZnMgO/Zn(S,O,OH)/Cu(In,Ga)Se{sub 2} solar cell (SC) metastability appearing during the measurement of its photovoltaic (PV) performances under AM 1.5 conditions, that is an increase with time of the PV parameters values before saturation, after about 20 min. These maximum values are not definitive since the SC returns to its initial state after about several hours. C-V profiling performed before and after the SC illumination exhibits a light soaking assisted charge redistribution within the absorber. This redistribution has been improved by thermal annealing at 200 C. This improvement is correlated with a decrease in defects density, measured with sub-gap photocurrent. (author)

  4. 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.

  5. 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.

  6. 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.

  7. Toxic effects of brake wear particles on epithelial lung cells in vitro

    Directory of Open Access Journals (Sweden)

    Perrenoud Alain

    2009-11-01

    Full Text Available Abstract Background Fine particulate matter originating from traffic correlates with increased morbidity and mortality. An important source of traffic particles is brake wear of cars which contributes up to 20% of the total traffic emissions. The aim of this study was to evaluate potential toxicological effects of human epithelial lung cells exposed to freshly generated brake wear particles. Results An exposure box was mounted around a car's braking system. Lung cells cultured at the air-liquid interface were then exposed to particles emitted from two typical braking behaviours („full stop“ and „normal deceleration“. The particle size distribution as well as the brake emission components like metals and carbons was measured on-line, and the particles deposited on grids for transmission electron microscopy were counted. The tight junction arrangement was observed by laser scanning microscopy. Cellular responses were assessed by measurement of lactate dehydrogenase (cytotoxicity, by investigating the production of reactive oxidative species and the release of the pro-inflammatory mediator interleukin-8. The tight junction protein occludin density decreased significantly (p Conclusion These findings suggest that the metals on brake wear particles damage tight junctions with a mechanism involving oxidative stress. Brake wear particles also increase pro-inflammatory responses. However, this might be due to another mechanism than via oxidative stress.

  8. 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.

  9. 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.

  10. Helicobacter pylori exploits a unique repertoire of type IV secretion system components for pilus assembly at the bacteria-host cell interface.

    Directory of Open Access Journals (Sweden)

    Carrie L Shaffer

    2011-09-01

    Full Text Available Colonization of the human stomach by Helicobacter pylori is an important risk factor for development of gastric cancer. The H. pylori cag pathogenicity island (cag PAI encodes components of a type IV secretion system (T4SS that translocates the bacterial oncoprotein CagA into gastric epithelial cells, and CagL is a specialized component of the cag T4SS that binds the host receptor α5β1 integrin. Here, we utilized a mass spectrometry-based approach to reveal co-purification of CagL, CagI (another integrin-binding protein, and CagH (a protein with weak sequence similarity to CagL. These three proteins are encoded by contiguous genes in the cag PAI, and are detectable on the bacterial surface. All three proteins are required for CagA translocation into host cells and H. pylori-induced IL-8 secretion by gastric epithelial cells; however, these proteins are not homologous to components of T4SSs in other bacterial species. Scanning electron microscopy analysis reveals that these proteins are involved in the formation of pili at the interface between H. pylori and gastric epithelial cells. ΔcagI and ΔcagL mutant strains fail to form pili, whereas a ΔcagH mutant strain exhibits a hyperpiliated phenotype and produces pili that are elongated and thickened compared to those of the wild-type strain. This suggests that pilus dimensions are regulated by CagH. A conserved C-terminal hexapeptide motif is present in CagH, CagI, and CagL. Deletion of these motifs results in abrogation of CagA translocation and IL-8 induction, and the C-terminal motifs of CagI and CagL are required for formation of pili. In summary, these results indicate that CagH, CagI, and CagL are components of a T4SS subassembly involved in pilus biogenesis, and highlight the important role played by unique constituents of the H. pylori cag T4SS.

  11. Interface failure by cavity growth to coalescence

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2000-01-01

    For a thin metal layer between ceramics ductile failure by the growth of voids along one of the interfaces is studied numerically. An axisymmetric cell model is used to represent an array of uniformly distributed hemispherical interface voids. The bonding to the ceramics gives rise to highly...

  12. Macrophages are required for dendritic cell uptake of respiratory syncytial virus from an infected epithelium.

    Science.gov (United States)

    Ugonna, Kelechi; Bingle, Colin D; Plant, Karen; Wilson, Kirsty; Everard, Mark L

    2014-01-01

    We have previously shown that the respiratory syncytial virus [RSV] can productively infect monocyte derived dendritic cells [MoDC] and remain dormant within the same cells for prolonged periods. It is therefore possible that infected dendritic cells act as a reservoir within the airways of individuals between annual epidemics. In the present study we explored the possibility that sub-epithelial DCs can be infected with RSV from differentiated bronchial epithelium and that in turn RSV from DCs can infect the epithelium. A dual co-culture model was established in which a differentiated primary airway epithelium on an Air Liquid Interface (ALI) was cultured on a transwell insert and MoDCs were subsequently added to the basolateral membrane of the insert. Further experiments were undertaken using a triple co-culture model in which in which macrophages were added to the apical surface of the differentiated epithelium. A modified RSV [rr-RSV] expressing a red fluorescent protein marker of replication was used to infect either the MoDCs or the differentiated epithelium and infection of the reciprocal cell type was assessed using confocal microscopy. Our data shows that primary epithelium became infected when rr-RSV infected MoDCs were introduced onto the basal surface of the transwell insert. MoDCs located beneath the epithelium did not become infected with virus from infected epithelial cells in the dual co-culture model. However when macrophages were present on the apical surface of the primary epithelium infection of the basal MoDCs occurred. Our data suggests that RSV infected dendritic cells readily transmit infection to epithelial cells even when they are located beneath the basal layer. However macrophages appear to be necessary for the transmission of infection from epithelial cells to basal dendritic cells.

  13. 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

    2013-09-21

    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.

  14. 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.

  15. Engineering graded tissue interfaces.

    Science.gov (United States)

    Phillips, Jennifer E; Burns, Kellie L; Le Doux, Joseph M; Guldberg, Robert E; García, Andrés J

    2008-08-26

    Interfacial zones between tissues provide specialized, transitional junctions central to normal tissue function. Regenerative medicine strategies focused on multiple cell types and/or bi/tri-layered scaffolds do not provide continuously graded interfaces, severely limiting the integration and biological performance of engineered tissue substitutes. Inspired by the bone-soft tissue interface, we describe a biomaterial-mediated gene transfer strategy for spatially regulated genetic modification and differentiation of primary dermal fibroblasts within tissue-engineered constructs. We demonstrate that zonal organization of osteoblastic and fibroblastic cellular phenotypes can be engineered by a simple, one-step seeding of fibroblasts onto scaffolds containing a spatial distribution of retrovirus encoding the osteogenic transcription factor Runx2/Cbfa1. Gradients of immobilized retrovirus, achieved via deposition of controlled poly(L-lysine) densities, resulted in spatial patterns of transcription factor expression, osteoblastic differentiation, and mineralized matrix deposition. Notably, this graded distribution of mineral deposition and mechanical properties was maintained when implanted in vivo in an ectopic site. Development of this facile and robust strategy is significant toward the regeneration of continuous interfacial zones that mimic the cellular and microstructural characteristics of native tissue.

  16. After Rigid Interfaces

    DEFF Research Database (Denmark)

    Troiano, Giovanni Maria

    Deformable and shape-changing interfaces are rapidly emerging in the field of human-computer interaction (HCI). Deformable interfaces provide users with newer input possibilities such as bending, squeezing, or stretching, which were impossible to achieve with rigid interfaces. Shape-changing inte......Deformable and shape-changing interfaces are rapidly emerging in the field of human-computer interaction (HCI). Deformable interfaces provide users with newer input possibilities such as bending, squeezing, or stretching, which were impossible to achieve with rigid interfaces. Shape...

  17. Adsorption of surfactants and polymers at interfaces

    Science.gov (United States)

    Rojas, Orlando Jose

    Surface tension and high-resolution laser light scattering experiments were used to investigate the adsorption of isomeric sugar-based surfactants at the air/liquid interface in terms of surfactant surface packing and rheology. Soluble monolayers of submicellar surfactant solutions exhibited a relatively viscous behavior. It was also proved that light scattering of high-frequency thermally-induced capillary waves can be utilized to study surfactant exchange between the surface and the bulk solution. Such analysis revealed the existence of a diffusional relaxation mechanism. A procedure based on XPS was developed for quantification, on an absolute basis, of polymer adsorption on mica and Langmuir-Blodgett cellulose films. The adsorption of cationic polyelectrolytes on negatively-charged solid surfaces was highly dependent on the polymer ionicity. It was found that the adsorption process is driven by electrostatic mechanisms. Charge overcompensation (or charge reversal) of mica occurred after adsorption of polyelectrolytes of ca. 50% charge density, or higher. It was demonstrated that low-charge-density polyelectrolytes adsorb on solid surfaces with an extended configuration dominated by loops and tails. In this case the extent of adsorption is limited by steric constraints. The conformation of the polyelectrolyte in the adsorbed layer is dramatically affected by the presence of salts or surfactants in aqueous solution. The phenomena which occur upon increasing the ionic strength are consistent with the screening of the electrostatic attraction between polyelectrolyte segments and solid surface. This situation leads to polyelectrolyte desorption accompanied by both an increase in the layer thickness and the range of the steric force. Adsorbed polyelectrolytes and oppositely charged surfactants readily associate at the solid/liquid interface. Such association induces polyelectrolyte desorption at a surfactant concentration which depends on the polyelectrolyte charge

  18. 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 $\

  19. Pseudomonas aeruginosa pyocyanin causes airway goblet cell hyperplasia and metaplasia and mucus hypersecretion by inactivating the transcriptional factor FoxA2.

    Science.gov (United States)

    Hao, Yonghua; Kuang, Zhizhou; Walling, Brent E; Bhatia, Shikha; Sivaguru, Mayandi; Chen, Yin; Gaskins, H Rex; Lau, Gee W

    2012-03-01

    The redox-active exotoxin pyocyanin (PCN) can be recovered in 100 µM concentrations in the sputa of bronchiectasis patients chronically infected with Pseudomonas aeruginosa (PA). However, the importance of PCN within bronchiectatic airways colonized by PA remains unrecognized. Recently, we have shown that PCN is required for chronic PA lung infection in mice, and that chronic instillation of PCN induces goblet cell hyperplasia (GCH), pulmonary fibrosis, emphysema and influx of immune cells in mouse airways. Many of these pathological features are strikingly similar to the mouse airways devoid of functional FoxA2, a transcriptional repressor of GCH and mucus biosynthesis. In this study, we postulate that PCN causes and exacerbates GCH and mucus hypersecretion in bronchiectatic airways chronically infected by PA by inactivating FoxA2. We demonstrate that PCN represses the expression of FoxA2 in mouse airways and in bronchial epithelial cells cultured at an air-liquid interface or conventionally, resulting in GCH, increased MUC5B mucin gene expression and mucus hypersecretion. Immunohistochemical and inhibitor studies indicate that PCN upregulates the expression of Stat6 and EGFR, both of which in turn repress the expression of FoxA2. These studies demonstrate that PCN induces GCH and mucus hypersecretion by inactivating FoxA2.

  20. 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.

  1. 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.

  2. Complex Interfaces Under Change

    DEFF Research Database (Denmark)

    Rosbjerg, Dan

    and 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...

  3. 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...

  4. 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

  5. Interfacing with the WEB

    CERN Document Server

    Dönszelmann, M

    1995-01-01

    Interfacing to the Web or programming interfaces for the Web is used to provide dynamic information for Web users. Using the Web as a transport system of information poses three constraints: namespace, statelessness and performance. To build interfaces on either server or client side of the Web one has to meet these constraints. Several examples, currently in use in High Energy Physics Experiments are described. They range from an interface to show where buildings are located to an interface showing active values of the On-line System of the DELPHI (CERN)..

  6. 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.

  7. Entanglement and topological interfaces

    CERN Document Server

    Brehm, Enrico M; Jaud, Daniel; Schmidt-Colinet, Cornelius

    2015-01-01

    In this paper we consider entanglement entropies in two-dimensional conformal field theories in the presence of topological interfaces. Tracing over one side of the interface, the leading term of the entropy remains unchanged. The interface however adds a subleading contribution, which can be interpreted as a relative (Kullback-Leibler) entropy with respect to the situation with no defect inserted. Reinterpreting boundaries as topological interfaces of a chiral half of the full theory, we rederive the left/right entanglement entropy in analogy with the interface case. We discuss WZW models and toroidal bosonic theories as examples.

  8. 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.

  9. 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...

  10. Mutual diffusion occurring at the interface between La₀.₆Sr₀.₄Co₀.₈Fe₀.₂O₃ cathode and Gd-doped ceria electrolyte during IT-SOFC cell preparation.

    Science.gov (United States)

    Li, Zhi-Peng; Toshiyuki, Mori; Auchterlonie, Graeme John; Zou, Jin; John, Drennan

    2011-07-01

    The microstructure and local chemistry of the interface between the screen-printed La(0.6)Sr(0.4)Co(0.8)Fe(0.2)O(3) (LSCF) thin film cathode and Gd-doped ceria (GDC) electrolyte substrate have been investigated. Elemental distribution analyses, by energy-dispersive X-ray spectroscopy operated in scanning transmission electron microscopy (STEM) mode, illustrate that all constituent elements in GDC and LSCF mutually diffuse across the LSCF/GDC interface, with equal diffusion length. This leads to the formation of mutual diffusion zones at the LSCF/GDC interfaces, with the resultant mixture of diffusing ions being associated with specific valence state changes, as verified by STEM electron energy loss spectroscopy analyses. Moreover, this mutual diffusion can result in microstructural changes, where superstructure formation is accompanied by enhancement of oxygen vacancy ordering at this region. Such mutual diffusion and associated microstructure evolution is considered to be detrimental to fuel cell efficiency and should be suppressed by lowering cell fabrication temperatures.

  11. Air bubble contact with endothelial cells causes a calcium-independent loss in mitochondrial membrane potential.

    Directory of Open Access Journals (Sweden)

    Peter Sobolewski

    Full Text Available OBJECTIVE: Gas microembolism remains a serious risk associated with surgical procedures and decompression. Despite this, the signaling consequences of air bubbles in the vasculature are poorly understood and there is a lack of pharmacological therapies available. Here, we investigate the mitochondrial consequences of air bubble contact with endothelial cells. METHODS AND RESULTS: Human umbilical vein endothelial cells were loaded with an intracellular calcium indicator (Fluo-4 and either a mitochondrial calcium indicator (X-Rhod-1 or mitochondrial membrane potential indicator (TMRM. Contact with 50-150 µm air bubbles induced concurrent rises in intracellular and mitochondrial calcium, followed by a loss of mitochondrial membrane potential. Pre-treating cells with 1 µmol/L ruthenium red, a TRPV family calcium channel blocker, did not protect cells from the mitochondrial depolarization, despite blocking the intracellular calcium response. Mitigating the interactions between the air-liquid interface and the endothelial surface layer with 5% BSA or 0.1% Pluronic F-127 prevented the loss of mitochondrial membrane potential. Finally, inhibiting protein kinase C-α (PKCα, with 5 µmol/L Gö6976, protected cells from mitochondrial depolarization, but did not affect the intracellular calcium response. CONCLUSIONS: Our results indicate that air bubble contact with endothelial cells activates a novel, calcium-independent, PKCα-dependent signaling pathway, which results in mitochondrial depolarization. As a result, mitochondrial dysfunction is likely to be a key contributor to the pathophysiology of gas embolism injury. Further, this connection between the endothelial surface layer and endothelial mitochondria may also play an important role in vascular homeostasis and disease.

  12. In vitro assessment of the soft tissue/implant interface using porcine gingival explants.

    Science.gov (United States)

    Abdulmajeed, Aous A; Willberg, Jaana; Syrjänen, Stina; Vallittu, Pekka K; Närhi, Timo O

    2015-01-01

    The biologic seal of peri-implant soft tissue is crucial for long-term prognosis of oral implants. This in vitro study describes a novel tissue culture model using porcine gingival explants to evaluate the soft tissue/implant interface. Two different types of substrates were investigated: (a) plain polymer: BisGMA-TEGDMA (50-50 %) and (b) unidirectional fiber-reinforced composite (FRC). Porcine gingival explants were obtained from a local slaughterhouse. The experimental implants (n = 4) were inserted into the middle of freshly excised porcine gingival explants and cultured at the air/liquid interface up to 14 days. Porcine gingival explants with no implants served as baseline controls. The specimens were fixed and processed for the preparation of undecalcified samples. Histological analysis of the soft tissue/implant interface was carried out using a light-microscope. Microscopic evaluation suggests that the gingival explants established epithelial and connective tissue attachment to both implant types over the incubation period. FRC surfaces seemed to have a favorable tissue response with a sign of an outward epithelial migration. However, tissue degeneration was observed at the end of the experiment. In conclusion, this in vitro model maintains mucosal viability and ability to histologically evaluate soft tissue attachment to biomaterials rendering it a time efficient and cost effective model that may reduce the need for animal experiments.

  13. Interleukin-13-induced MUC5AC expression is regulated by a PI3K-NFAT3 pathway in mouse tracheal epithelial cells.

    Science.gov (United States)

    Yan, Fugui; Li, Wen; Zhou, Hongbin; Wu, Yinfang; Ying, Songmin; Chen, Zhihua; Shen, Huahao

    2014-03-28

    Interleukin-13 (IL-13) plays a critical role in asthma mucus overproduction, while the mechanisms underlying this process are not fully elucidated. Previous studies showed that nuclear factor of activated T cells (NFAT) is involved in the pathogenesis of asthma, but whether it can directly regulate IL-13-induced mucus (particularly MUC5AC) production is still not clear. Here we showed that IL-13 specifically induced NFAT3 activation through promoting its dephosphorylation in air-liquid interface (ALI) cultures of mouse tracheal epithelial cells (mTECs). Furthermore, both Cyclosporin A (CsA, a specific NFAT inhibitor) and LY294002 (a Phosphoinositide 3-kinase (PI3K) inhibitor) significantly blocked IL-13-induced MUC5AC mRNA and protein production through the inhibition of NFAT3 activity. We also confirmed that CsA could not influence the forkhead Box A2 (Foxa2) and mouse calcium dependent chloride channel 3 (mClca3) expression in IL-13-induced MUC5AC production, which both are known to be important in IL-13-stimulated mucus expression. Our study is the first to demonstrate that the PI3K-NFAT3 pathway is positively involved in IL-13-induced mucus production, and provided novel insights into the molecular mechanism of asthma mucus hypersecretion.

  14. Spray algorithm without interface construction

    Science.gov (United States)

    Al-Kadhem Majhool, Ahmed Abed; Watkins, A. P.

    2012-05-01

    This research is aimed to create a new and robust family of convective schemes to capture the interface between the dispersed and the carrier phases in a spray without the need to build up the interface boundary. The selection of the Weighted Average Flux (WAF) scheme is due to this scheme being designed to deal with random flux scheme which is second-order accurate in space and time. The convective flux in each cell face utilizes the WAF scheme blended with Switching Technique for Advection and Capturing of Surfaces (STACS) scheme for high resolution flux limiters. In the next step, the high resolution scheme is blended with the WAF scheme to provide the sharpness and boundedness of the interface by using switching strategy. In this work, the Eulerian-Eulerian framework of non-reactive turbulent spray is set in terms of theoretical proposed methodology namely spray moments of drop size distribution, presented by Beck and Watkins [1]. The computational spray model avoids the need to segregate the local droplet number distribution into parcels of identical droplets. The proposed scheme is tested on capturing the spray edges in modelling hollow cone sprays without need to reconstruct two-phase interface. A test is made on simple comparison between TVD scheme and WAF scheme using the same flux limiter on convective flow hollow cone spray. Results show the WAF scheme gives a better prediction than TVD scheme. The only way to check the accuracy of the presented models is by evaluating the spray sheet thickness.

  15. A scattering model for nano-textured interfaces and its application in opto-electrical simulations of thin-film silicon solar cells

    NARCIS (Netherlands)

    Jäger, K.; Fischer, M.; Van Swaaij, R.A.C.M.M.; Zeman, M.

    2012-01-01

    We present a scattering model based on the scalar scattering theory that allows estimating far field scattering properties in both transmission and reflection for nano-textured interfaces. We first discuss the theoretical formulation of the scattering model and validate it for nano-textures with dif

  16. Turbomachine Interface Sealing

    Science.gov (United States)

    Hendricks, Robert C.; Chupp, Raymond E.; Lattime, Scott B.; Steinetz, Bruce M.

    2005-01-01

    Sealing interfaces and coatings, like lubricants, are sacrificial, giving up their integrity for the benefit of the component. Clearance control is a major issue in power systems turbomachine design and operational life. Sealing becomes the most cost-effective way to enhance system performance. Coatings, films, and combined use of both metals and ceramics play a major role in maintaining interface clearances in turbomachine sealing and component life. This paper focuses on conventional and innovative materials and design practices for sealing interfaces.

  17. Popeye Project: ROV interface

    Energy Technology Data Exchange (ETDEWEB)

    Scates, C.R.; Hernandez, D.A.; Hickok, D.D.

    1996-12-31

    This paper discusses the Remote Operated Vehicle (ROV) interface with the Popeye Project Subsea System. It describes the ROV-related plans, design philosophies, intervention tasks, tooling/equipment requirements, testing activities, and offshore installation experiences. Early identification and continuous consideration of the ROV interfaces significantly improved the overall efficiency of equipment designs and offshore operations. The Popeye Project helped advance the technology and standardization of ROV interfaces for deep water subsea production systems.

  18. 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.

  19. 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...

  20. Shape-changing interfaces:

    DEFF Research Database (Denmark)

    Rasmussen, Majken Kirkegård; Pedersen, Esben Warming; Petersen, Marianne Graves;

    2015-01-01

    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 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...

  1. Mycoplasma ovipneumoniae induces inflammatory response in sheep airway epithelial cells via a MyD88-dependent TLR signaling pathway.

    Science.gov (United States)

    Xue, Di; Ma, Yan; Li, Min; Li, Yanan; Luo, Haixia; Liu, Xiaoming; Wang, Yujiong

    2015-01-15

    Mycoplasma ovipneumoniae (M. ovipneumoniae) is a bacterium that specifically infects sheep and goat and causes ovine infectious pleuropneumonia. In an effort to understand the pathogen-host interaction between the M. ovipneumoniae and airway epithelial cells, we investigated the host inflammatory response using a primary air-liquid interface (ALI) epithelial culture model generated from bronchial epithelial cells of Ningxia Tan sheep (Ovis aries). The ALI culture of sheep bronchial epithelial cells showed a fully differentiated epithelium comprising distinct epithelial types, including the basal, ciliated and goblet cells. Exposure of ALI cultures to M. ovipneumoniae led to increased expression of Toll-like receptors (TLRs), and components of the myeloid differentiation factor 88 (MyD88)-dependent TLR signaling pathway, including the MyD88, TNF receptor-associated factor 6 (TRAF6), IL-1 receptor-associated kinases (IRAKs) and nuclear factor-kappa B (NF-κB), as well as subsequent pro-inflammatory cytokines in the epithelial cells. Of interest, infection with M. ovipneumoniae failed to induce the expression of TANK-binding kinase 1 (TBK1), TRAF3 and interferon regulatory factor 3 (IRF3), key components of the MyD88-independent signaling pathway. These results suggest that the MyD88-dependent TLR pathway may play a crucial role in sheep airway epithelial cells in response to M. ovipneumoniae infection, which also indicate that the ALI culture system may be a reliable model for investigating pathogen-host interactions between M. ovipneumoniae and airway epithelial cells.

  2. Ex vivo 2D and 3D HSV-2 infection model using human normal vaginal epithelial cells.

    Science.gov (United States)

    Zhu, Yaqi; Yang, Yan; Guo, Juanjuan; Dai, Ying; Ye, Lina; Qiu, Jianbin; Zeng, Zhihong; Wu, Xiaoting; Xing, Yanmei; Long, Xiang; Wu, Xufeng; Ye, Lin; Wang, Shubin; Li, Hui

    2017-01-27

    Herpes simplex virus type 2 (HSV-2) infects human genital mucosa and establishes life-long latent infection. It is unmet need to establish a human cell-based microphysiological system for virus biology and anti-viral drug discovery. One of barriers is lacking of culture system of normal epithelial cells in vitro over decades. In this study, we established human normal vaginal epithelial cell (HNVEC) culture using co-culture system. HNVEC cells were then propagated rapidly and stably in a defined culture condition. HNVEC cells exhibited a normal diploid karyotype and formed the well-defined and polarized spheres in matrigel three-dimension (3D) culture, while malignant cells (HeLa) formed disorganized and nonpolar solid spheres. HNVEC cells had a normal cellular response to DNA damage and had no transforming property using soft agar assays. HNVEC expressed epithelial marker cytokeratin 14 (CK14) and p63, but not cytokeratin 18 (CK18). Next, we reconstructed HNVEC-derived 3D vaginal epithelium using air-liquid interface (ALI) culture. This 3D vaginal epithelium has the basal and apical layers with expression of epithelial markers as its originated human vaginal tissue. Finally, we established an HSV-2 infection model based on the reconstructed 3D vaginal epithelium. After inoculation of HSV-2 (G strain) at apical layer of the reconstructed 3D vaginal epithelium, we observed obvious pathological effects gradually spreading from the apical layer to basal layer with expression of a viral protein. Thus, we established an ex vivo 2D and 3D HSV-2 infection model that can be used for HSV-2 virology and anti-viral drug discovery.

  3. Controlling the assembly of hydrophobized gold nanoparticles at the air-water interface by varying the interfacial tension

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Shweta; Singh, Nahar [Material Characterization Division, National Physical Laboratory, New Delhi-110012 (India); Sastry, Murali [Tata Chemical Innovation Center, Anmol Pride, Baner Road, Pune-45 (India); Kakkar, Rita [Department of Chemistry, Delhi University, Delhi-110007 (India); Pasricha, Renu, E-mail: pasrichar@mail.nplindia.ernet.i [Material Characterization Division, National Physical Laboratory, New Delhi-110012 (India)

    2010-11-30

    Controlled assembly is the key to harness the nanoscale properties of nanoparticles in most technological applications and it has been an important challenge as it leads to the manipulation of interparticle properties. The present work depicts the control of the assembly of nanoparticles in the monolayers by evaporation kinetics and particle interactions at the air-liquid interface. In the presence of attractive particle-particle and particle-monolayers interactions, nanoparticles self assemble into a superlattice structure upon drying from a colloidal suspension on to the preformed lipid monolayers. This self-assembly mechanism produces monolayers with long-range ordering. However, rapid dewetting and high rate of evaporation can significantly undermine the extent of ordering. Using gold nanoparticles as vehicles for experimentation and by changing the monolayers and solvent, we here demonstrate that the extent of ordering of nanoparticles can be controlled.

  4. Acute toxicity of silver and carbon nanoaerosols to normal and cystic fibrosis human bronchial epithelial cells.

    Science.gov (United States)

    Jeannet, Natalie; Fierz, Martin; Schneider, Sarah; Künzi, Lisa; Baumlin, Nathalie; Salathe, Matthias; Burtscher, Heinz; Geiser, Marianne

    2016-01-01

    Inhalation of engineered nanoparticles (NP) poses a still unknown risk. Individuals with chronic lung diseases are expected to be more vulnerable to adverse effects of NP than normal subjects, due to altered respiratory structures and functions. Realistic and dose-controlled aerosol exposures were performed using the deposition chamber NACIVT. Well-differentiated normal and cystic fibrosis (CF) human bronchial epithelia (HBE) with established air-liquid interface and the human bronchial epithelial cell line BEAS-2B were exposed to spark-generated silver and carbon nanoaerosols (20 nm diameter) at three different doses. Necrotic and apoptotic cell death, pro-inflammatory response, epithelial function and morphology were assessed within 24 h after aerosol exposure. NP exposure resulted in significantly higher necrosis in CF than normal HBE and BEAS-2B cells. Before and after NP treatment, CF HBE had higher caspase-3 activity and secreted more IL-6 and MCP-1 than normal HBE. Differentiated HBE had higher baseline secretion of IL-8 and less caspase-3 activity and MCP-1 secretion compared to BEAS-2B cells. These biomarkers increased moderately in response to NP exposure, except for MCP-1, which was reduced in HBE after AgNP treatment. No functional and structural alterations of the epithelia were observed in response to NP exposure. Significant differences between cell models suggest that more than one and fully differentiated HBE should be used in future toxicity studies of NP in vitro. Our findings support epidemiologic evidence that subjects with chronic airway diseases are more vulnerable to adverse effects of particulate air pollution. Thus, this sub-population needs to be included in nano-toxicity studies.

  5. 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.

  6. The User Interface.

    Science.gov (United States)

    Lindeman, Martha J.; And Others

    1989-01-01

    The first of three articles on the design of user interfaces for information retrieval systems discusses the need to examine types of display, prompting, and input as separate entities. The second examines the use of artificial intelligence in creating natural language interfaces, and the third outlines standards for case studies in human computer…

  7. 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...

  8. Verden som interface

    DEFF Research Database (Denmark)

    2007-01-01

    Oversættelse af Peter Weibels tekst "The World as Interface" i Passepartout # 27. Interfacekulturens æstetik. Udgivelsesdato: 28.04.07......Oversættelse af Peter Weibels tekst "The World as Interface" i Passepartout # 27. Interfacekulturens æstetik. Udgivelsesdato: 28.04.07...

  9. Designing the Instructional Interface.

    Science.gov (United States)

    Lohr, L. L.

    2000-01-01

    Designing the instructional interface is a challenging endeavor requiring knowledge and skills in instructional and visual design, psychology, human-factors, ergonomic research, computer science, and editorial design. This paper describes the instructional interface, the challenges of its development, and an instructional systems approach to its…

  10. Entanglement and topological interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Brehm, E.; Brunner, I.; Jaud, D.; Schmidt-Colinet, C. [Arnold Sommerfeld Center, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333, Muenchen (Germany)

    2016-06-15

    In this paper we consider entanglement entropies in two-dimensional conformal field theories in the presence of topological interfaces. Tracing over one side of the interface, the leading term of the entropy remains unchanged. The interface however adds a subleading contribution, which can be interpreted as a relative (Kullback-Leibler) entropy with respect to the situation with no defect inserted. Reinterpreting boundaries as topological interfaces of a chiral half of the full theory, we rederive the left/right entanglement entropy in analogy with the interface case. We discuss WZW models and toroidal bosonic theories as examples. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. 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. ...

  12. Understanding 3C-SiC/SiO2 interfaces in SiC-nanofiber based solar cells from ab initio theory

    Science.gov (United States)

    Nugraha, Taufik Adi; Wippermann, Stefan

    2015-03-01

    Nanostructured materials - such as e. g. hybrid nanocomposites consisting of inorganic semiconducting nanofibers and organic surfactants - provide genuinely novel pathways to exceed the Shockley-Queisser limit for solar energy conversion. The synthesis of such functionalized nanofibers can be performed completely using only inexpensive wet chemical solution processing. However, the synthesis conditions often lead to complex interfacial structures involving thin oxide layers between the nanofiber and surfactants, whose atomistic details are poorly understood at best. Here we present a combined density functional theory and tight binding investigation of interfaces between 3C-SiC nanofiber surfaces and SiO2. Considering a wide variety of possible interfacial structures we utilize a grand canonical approach to generate a phase diagram and predict the structural details of the interface as a function of the chemical potentials of Si, O and H. This study provides directions about how the synthesis conditions lead to specific types of interfacial structures and their impact on the electronic properties of the interface. The authors wish to thank U. Gerstmann, S. Greulich-Weber and W. G. Schmidt for helpful discussions. S. W. acknowledges BMBF NanoMatFutur Grant No. 13N12972.

  13. 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.

  14. Hypervelocity Impact on Interfaces: A Molecular-Dynamics Simulations Study

    Science.gov (United States)

    Bachlechner, Martina E.; Owens, Eli T.; Leonard, Robert H.; Cockburn, Bronwyn C.

    2008-03-01

    Silicon/silicon nitride interfaces are found in micro electronics and solar cells. In either application the mechanical integrity of the interface is of great importance. Molecular-dynamics simulations are performed to study the failure of interface materials under the influence of hypervelocity impact. Silicon nitride plates impacting on silicon/silicon nitride interface targets of different thicknesses result in structural phase transformation and delamination at the interface. Detailed analyses of atomic velocities, bond lengths, and bond angles are used to qualitatively examine the respective failure mechanisms.

  15. Cellular nanotechnology: making biological interfaces smarter.

    Science.gov (United States)

    Mendes, Paula M

    2013-12-21

    Recently, there has been an outburst of research on engineered cell-material interfaces driven by nanotechnology and its tools and techniques. This tutorial review begins by providing a brief introduction to nanostructured materials, followed by an overview of the wealth of nanoscale fabrication and analysis tools available for their development. This background serves as the basis for a discussion of early breakthroughs and recent key developments in the endeavour to develop nanostructured materials as smart interfaces for fundamental cellular studies, tissue engineering and regenerative medicine. The review covers three major aspects of nanostructured interfaces - nanotopographical control, dynamic behaviour and intracellular manipulation and sensing - where efforts are continuously being made to further understand cell function and provide new ways to control cell behaviour. A critical reflection of the current status and future challenges are discussed as a conclusion to the review.

  16. Phagocytosis of Aspergillus fumigatus conidia by primary nasal epithelial cells in vitro

    Directory of Open Access Journals (Sweden)

    Khoufache Khaled

    2008-06-01

    Full Text Available Abstract Background Invasive aspergillosis, which is mainly caused by the fungus Aspergillus fumigatus, is an increasing problem in immunocompromised patients. Infection occurs by inhalation of airborne conidia, which are first encountered by airway epithelial cells. Internalization of these conidia into the epithelial cells could serve as a portal of entry for this pathogenic fungus. Results We used an in vitro model of primary cultures of human nasal epithelial cells (HNEC at an air-liquid interface. A. fumigatus conidia were compared to Penicillium chrysogenum conidia, a mould that is rarely responsible for invasive disease. Confocal microscopy, transmission electron microscopy, and anti-LAMP1 antibody labeling studies showed that conidia of both species were phagocytosed and trafficked into a late endosomal-lysosomal compartment as early as 4 h post-infection. In double immunolabeling experiments, the mean percentage of A. fumigatus conidia undergoing phagocytosis 4 h post-infection was 21.8 ± 4.5%. Using combined staining with a fluorescence brightener and propidium iodide, the mean rate of phagocytosis was 18.7 ± 9.3% and the killing rate 16.7 ± 7.5% for A. fumigatus after 8 h. The phagocytosis rate did not differ between the two fungal species for a given primary culture. No germination of the conidia was observed until 20 h of observation. Conclusion HNEC can phagocytose fungal conidia but killing of phagocytosed conidia is low, although the spores do not germinate. This phagocytosis does not seem to be specific to A. fumigatus. Other immune cells or mechanisms are required to kill A. fumigatus conidia and to avoid further invasion.

  17. 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....

  18. 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

  19. 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

  20. Hard-Soft Tissue Interface Engineering.

    Science.gov (United States)

    Armitage, Oliver E; Oyen, Michelle L

    2015-01-01

    The musculoskeletal system is comprised of three distinct tissue categories: structural mineralized tissues, actuating muscular soft tissues, and connective tissues. Where connective tissues - ligament, tendon and cartilage - meet with bones, a graded interface in mechanical properties occurs that allows the transmission of load without creating stress concentrations that would cause tissue damage. This interface typically occurs over less than 1 mm and contains a three order of magnitude difference in elastic stiffness, in addition to changes in cell type and growth factor concentrations among others. Like all engineered tissues, the replication of these interfaces requires the production of scaffolds that will provide chemical and mechanical cues, resulting in biologically accurate cellular differentiation. For interface tissues however, the scaffold must provide spatially graded chemical and mechanical cues over sub millimetre length scales. Naturally, this complicates the manufacture of the scaffolds and every stage of their subsequent cell seeding and growth, as each region has different optimal conditions. Given the higher degree of difficulty associated with replicating interface tissues compared to surrounding homogeneous tissues, it is likely that the development of complex musculoskeletal tissue systems will continue to be limited by the engineering of connective tissues interfaces with bone.

  1. Interface high-temperature superconductivity

    Science.gov (United States)

    Wang, Lili; Ma, Xucun; Xue, Qi-Kun

    2016-12-01

    Cuprate high-temperature superconductors consist of two quasi-two-dimensional (2D) substructures: CuO2 superconducting layers and charge reservoir layers. The superconductivity is realized by charge transfer from the charge reservoir layers into the superconducting layers without chemical dopants and defects being introduced into the latter, similar to modulation-doping in the semiconductor superlattices of AlGaAs/GaAs. Inspired by this scheme, we have been searching for high-temperature superconductivity in ultra-thin films of superconductors epitaxially grown on semiconductor/oxide substrates since 2008. We have observed interface-enhanced superconductivity in both conventional and unconventional superconducting films, including single atomic layer films of Pb and In on Si substrates and single unit cell (UC) films of FeSe on SrTiO3 (STO) substrates. The discovery of high-temperature superconductivity with a superconducting gap of ∼20 meV in 1UC-FeSe/STO has stimulated tremendous interest in the superconductivity community, for it opens a new avenue for both raising superconducting transition temperature and understanding the pairing mechanism of unconventional high-temperature superconductivity. Here, we review mainly the experimental progress on interface-enhanced superconductivity in the three systems mentioned above with emphasis on 1UC-FeSe/STO, studied by scanning tunneling microscopy/spectroscopy, angle-resolved photoemission spectroscopy and transport experiments. We discuss the roles of interfaces and a possible pairing mechanism inferred from these studies.

  2. Reduction in (pro-)inflammatory responses of lung cells exposed in vitro to diesel exhaust treated with a non-catalyzed diesel particle filter

    Science.gov (United States)

    Steiner, Sandro; Czerwinski, Jan; Comte, Pierre; Müller, Loretta L.; Heeb, Norbert V.; Mayer, Andreas; Petri-Fink, Alke; Rothen-Rutishauser, Barbara

    2013-12-01

    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 acted highly oxidative, even though to a lesser extent than unfiltered exhaust (quantification of total reduced glutathione), and both exhaust types triggered comparable responses to oxidative stress (measurement of heme-oxygenase 1 (HMOX1) and superoxide-dismutase (SOD1) gene expression). Further, diesel exhaust filtration significantly reduced pro-inflammatory responses (measurement of tumor necrosis factor (TNF) and interleukin-8 (IL-8) gene expression and quantification of the secretion of their gene products TNF-α and IL-8). Because inflammatory processes are central to the onset of adverse respiratory health effects caused by diesel exhaust inhalation, our results imply that DPFs may make a valuable contribution to the detoxification of diesel vehicle emissions. The induction of significant oxidative stress by filtered diesel exhaust however, also implies that the non-particulate exhaust components also need to be considered for lung cell risk assessment.

  3. Deposition of a thin film of TiOx from a titanium metal target as novel blocking layers at conducting glass/TiO2 interfaces in ionic liquid mesoscopic TiO2 dye-sensitized solar cells.

    Science.gov (United States)

    Xia, Jiangbin; Masaki, Naruhiko; Jiang, Kejian; Yanagida, Shozo

    2006-12-21

    In dye-sensitized TiO2 solar cells, charge recombination processes at interfaces between fluorine-doped tin oxide (FTO), TiO2, dye, and electrolyte play an important role in limiting the photon-to-electron conversion efficiency. From this point of view, a high work function material such as titanium deposited by sputtering on FTO has been investigated as an effective blocking layer for preventing electron leakage from FTO without influencing electron injection. X-ray photoelectron spectroscopy analysis indicates that different species of Ti (Ti4+, Ti3+, Ti2+, and a small amount of Ti0) exist on FTO. Electrochemical and photoelectrochemical measurements reveal that thin films of titanium species, expressed as TiOx, work as a compact blocking layer between FTO and TiO2 nanocrystaline film, improving Voc and the fill factor, finally giving a better conversion efficiency for dye-sensitized TiO2 solar cells with ionic liquid electrolytes.

  4. 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...

  5. Galaxy-like organization of floaters at the air-water interface of Faraday waves

    Science.gov (United States)

    Alarcón, Héctor; Périnet, Nicolas; Gutiérrez, Pablo; Gordillo, Leonardo; Mujica, Nicolás

    2016-11-01

    The fluid properties mismatch across an air-liquid interface allows to trap particles at it. These particles are called floaters and appear in nature at different scales: plankton, organic residues, and garbage, all relevant for the oceanic ecosystem. In static systems they tend to attract or repel each other, depending on their wetting properties and buoyancy. When they are subjected to a flow, such as surface waves, they may drift and form structures at the interface. In a recent work using PIV on Faraday waves, we have measured a streaming flow that emerges inside the bulk, leading to a slow circulation of fluid particles across the liquid. The flow is mainly generated by the viscous shearing at the walls of the container. Our new experiments show that this flow has a remarkable effect on the drift of small hydrophilic particles (floaters), which leads to a rare arrangement of the floaters that resemble rotating galaxies. The forcing amplitude determines the galaxy shape, controlling the number and the length of its arms as well as its rotation velocity. Thanks to FONDECYT POSTDOCTORADO N°3160341, N°3140522, N°3140550.

  6. Thermal coupling at aqueous and biomolecular interfaces

    Science.gov (United States)

    Shenogina, Natalia B.

    Heat flow in the materials with nanoscopic features is dominated by thermal properties of the interfaces. While thermal properties of the solid-solid and solid-liquid interfaces are well studied, research of the thermal transport properties across soft (liquid-liquid) interfaces is very limited. Such interfaces are, however, plentiful in biological systems. In such systems the temperature control is of a great importance, because biochemical reactions, conformation of biomolecules as well as processes in biological cells and membranes have strong temperature sensitivity. The critical ingredient to temperature control in biological systems is the understanding of heat flow and thermal coupling across soft interfaces. To investigate heat transfer across biological and aqueous interfaces we chose to study a number of soft interfacial systems by means of molecular dynamic simulations. One of the interfaces under our investigation is the interface between protein (specifically green fluorescent protein) and water. Using this model we concentrated on the importance of vibrational frequency on coupling between water and proteins, and on significant differences between the roles of low and high frequency vibrations. Our thermal interfacial analysis allowed us to shed new light on to the issue of protein to water slaving, i.e., the concept of water controlling protein dynamics. Considering that the surface of the protein is composed of a complicated mixture of the hydrophobic and hydrophilic domains, to systematically explore the role of interfacial interactions we studied less complicated models with homogenous interfaces whith interfacial chemistry that could be changed in a controlled manner. We demonstrated that thermal transport measurements can be used to probe interfacial environments and to quantify interfacial bonding strength. Such ability provides a unique opportunity to characterize a variety of interfaces, which can be difficult to achieve with more direct

  7. Interface-Based Design

    Science.gov (United States)

    2004-01-01

    Lecture Notes in Computer Science 1466, pages 163–178. Springer-Verlag, 1998. A. Chakrabarti, L. de Alfaro, T.A...Henzinger, M. Jurdziński, and F.Y.C. Mang. Interface compatibility checking for software modules. In Proc. Computer-Aided Verification, Lecture Notes in Computer Science 2404...bidirectional component interfaces. In Proc. Computer-Aided Verification, Lecture Notes in Computer Science 2404, pages 414–427.

  8. Ab initioelectron paramagnetic resonance study of 3C-SiC/SiO2 interfaces in SiC-nanofiber based solar cells

    Science.gov (United States)

    Nugraha, Taufik Adi; Gerstmann, Uwe; Schmidt, Wolfgang Gero; Wippermann, Stefan

    Semiconducting nanocomposites, e. g. hybrid materials based on inorganic semiconducting 3C-SiC nanofibers and organic surfactants, provide genuinely novel pathways to exceed the Shockley-Queisser limit for solar energy conversion. The synthesis of such functionalized fibers can be performed completely using only inexpensive wet chemical solution processing. During synthesis a thin passivation layer is introduced between the SiC-fiber and surfactants, e. g. the native oxide, whose atomistic details are poorly understood. In this study, we utilize unpaired spins in interfacial defects to probe the local chemical environment with ab initio EPR (Electron Paramagnetic Resonance) calculations, which can be directly compared to experiment. Considering a wide variety of possible interfacial structures, a grand canonical approach is used to generate a phase diagram of the 3C-SiC/SiO2 interface as a function of the chemical potentials of Si, O and H, to provide favorable interfacial structures for g-tensor calculations. This study provides directions about specific types of interfacial defects and their impact on the electronic properties of the interface. The authors wish to thank S. Greulich-Weber for helpful discussions. S. W. acknowledges BMBF NanoMatFutur Grant No. 13N12972.

  9. Interfaces: nanometric dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, T J [School of Informatics, University of Wales Bangor, Dean Street, Bangor, Gwynedd, LL70 9PX (United Kingdom)

    2005-01-21

    The incorporation of nanometric size particles in a matrix to form dielectric composites shows promise of materials (nanodielectrics) with new and improved properties. It is argued that the properties of the interfaces between the particles and the matrix, which will themselves be of nanometric dimensions, will have an increasingly dominant role in determining dielectric performance as the particle size decreases. The forces that determine the electrical and dielectric properties of interfaces are considered, with emphasis on the way in which they might influence composite behaviour. A number of examples are given in which interfaces at the nanometric level exercise both passive and active control over dielectric, optical and conductive properties. Electromechanical properties are also considered, and it is shown that interfaces have important electrostrictive and piezoelectric characteristics. It is demonstrated that the process of poling, namely subjecting macroscopic composite materials to electrical stress and raised temperatures to create piezoelectric materials, can be explained in terms of optimizing the collective response of the nanometric interfaces involved. If the electrical and electromechanical features are coupled to the long-established electrochemical properties, interfaces represent highly versatile active elements with considerable potential in nanotechnology.

  10. Interfaces: nanometric dielectrics

    Science.gov (United States)

    Lewis, T. J.

    2005-01-01

    The incorporation of nanometric size particles in a matrix to form dielectric composites shows promise of materials (nanodielectrics) with new and improved properties. It is argued that the properties of the interfaces between the particles and the matrix, which will themselves be of nanometric dimensions, will have an increasingly dominant role in determining dielectric performance as the particle size decreases. The forces that determine the electrical and dielectric properties of interfaces are considered, with emphasis on the way in which they might influence composite behaviour. A number of examples are given in which interfaces at the nanometric level exercise both passive and active control over dielectric, optical and conductive properties. Electromechanical properties are also considered, and it is shown that interfaces have important electrostrictive and piezoelectric characteristics. It is demonstrated that the process of poling, namely subjecting macroscopic composite materials to electrical stress and raised temperatures to create piezoelectric materials, can be explained in terms of optimizing the collective response of the nanometric interfaces involved. If the electrical and electromechanical features are coupled to the long-established electrochemical properties, interfaces represent highly versatile active elements with considerable potential in nanotechnology.

  11. Lectures on random interfaces

    CERN Document Server

    Funaki, Tadahisa

    2016-01-01

    Interfaces are created to separate two distinct phases in a situation in which phase coexistence occurs. This book discusses randomly fluctuating interfaces in several different settings and from several points of view: discrete/continuum, microscopic/macroscopic, and static/dynamic theories. The following four topics in particular are dealt with in the book. Assuming that the interface is represented as a height function measured from a fixed-reference discretized hyperplane, the system is governed by the Hamiltonian of gradient of the height functions. This is a kind of effective interface model called ∇φ-interface model. The scaling limits are studied for Gaussian (or non-Gaussian) random fields with a pinning effect under a situation in which the rate functional of the corresponding large deviation principle has non-unique minimizers. Young diagrams determine decreasing interfaces, and their dynamics are introduced. The large-scale behavior of such dynamics is studied from the points of view of the hyd...

  12. Metabolic detoxification pathways for 5-methoxy-sterigmatocystin in primary tracheal epithelial cells.

    Science.gov (United States)

    Cabaret, Odile; Puel, Olivier; Botterel, Françoise; Delaforge, Marcel; Bretagne, Stéphane

    2014-01-01

    1.  The health effects of inhaled mycotoxins remain poorly documented despite their presence in bioaerosols. 5-methoxy-sterigmatocystin is produced in association with sterigmatocystin by some Aspergillus spp., sometimes in larger amounts than sterigmatocystin. Whereas sterigmatocystin can be metabolized through cytochromes P450 (CYP), UDP-glucuronosyltransferases and sulfotransferases in airway epithelial cells, little is known about 5-methoxy-sterigmatocystin. 2.  The 5-methoxy-sterigmatocystin metabolites were analyzed using human recombinant CYP and porcine tracheal epithelial cell (PTEC) primary cultures at an air-liquid interface. The induction of xenobiotic-metabolizing enzymes was examined by real-time quantitative PCR for mRNA expression and 7-ethoxyresorufin O-deethylation activity. 3.  CYP1A1 metabolized 5-methoxy-sterigmatocystin into hydroxy-nor-methoxy-sterigmatocystin, nor-methoxy-sterigmatocystin and dihydroxy-methoxy-sterigmatocystin. CYP1A2 led to monohydroxy-methoxy-sterigmatocystin. In PTEC, 5-methoxy-sterigmatocystin metabolism resulted into a glucuroconjugate of 5-methoxy-sterigmatocystin, a sulfoconjugate and a glucuroconjugate of monohydroxy-methoxy-sterigmatocystin. The exposure of PTEC for 24 h to 1 µM 5-methoxy-sterigmatocystin induced a significant increase in the mRNA levels of CYP1A1, without significant induction of the 7-ethoxyresorufin O-deethylation activity. 4.  These data suggest that 5-methoxy-sterigmatocystin is mainly detoxified in airway cells through conjugation, as sterigmatocystin. However, while CYP produced a reactive metabolite of sterigmatocystin, no such metabolite was detected with 5-methoxy-sterigmatocystin. Nevertheless, 5-methoxy-sterigmatocystin increases the CYP1A1 mRNA levels. The long-term consequences remain unknown.

  13. 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.

  14. 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.

  15. Bile acids stimulate chloride secretion through CFTR and calcium-activated Cl- channels in Calu-3 airway epithelial cells.

    Science.gov (United States)

    Hendrick, Siobhán M; Mroz, Magdalena S; Greene, Catherine M; Keely, Stephen J; Harvey, Brian J

    2014-09-01

    Bile acids resulting from the aspiration of gastroesophageal refluxate are often present in the lower airways of people with cystic fibrosis and other respiratory distress diseases. Surprisingly, there is little or no information on the modulation of airway epithelial ion transport by bile acids. The secretory effect of a variety of conjugated and unconjugated secondary bile acids was investigated in Calu-3 airway epithelial cells grown under an air-liquid interface and mounted in Ussing chambers. Electrogenic transepithelial ion transport was measured as short-circuit current (Isc). The taurine-conjugated secondary bile acid, taurodeoxycholic acid (TDCA), was found to be the most potent modulator of basal ion transport. Acute treatment (5 min) of Calu-3 cells with TDCA (25 μM) on the basolateral side caused a stimulation of Isc, and removal of extracellular Cl(-) abolished this response. TDCA produced an increase in the cystic fibrosis transmembrane conductance regulator (CFTR)-dependent current that was abolished by pretreatment with the CFTR inhibitor CFTRinh172. TDCA treatment also increased Cl(-) secretion through calcium-activated chloride (CaCC) channels and increased the Na(+)/K(+) pump current. Acute treatment with TDCA resulted in a rapid cellular influx of Ca(2+) and increased cAMP levels in Calu-3 cells. Bile acid receptor-selective activation with INT-777 revealed TGR5 localized at the basolateral membrane as the receptor involved in TDCA-induced Cl(-) secretion. In summary, we demonstrate for the first time that low concentrations of bile acids can modulate Cl(-) secretion in airway epithelial cells, and this effect is dependent on both the duration and sidedness of exposure to the bile acid.

  16. HO-1 inhibits IL-13-induced goblet cell hyperplasia associated with CLCA1 suppression in normal human bronchial epithelial cells.

    Science.gov (United States)

    Mishina, Kei; Shinkai, Masaharu; Shimokawaji, Tadasuke; Nagashima, Akimichi; Hashimoto, Yusuke; Inoue, Yoriko; Inayama, Yoshiaki; Rubin, Bruce K; Ishigatsubo, Yoshiaki; Kaneko, Takeshi

    2015-12-01

    Mucus hypersecretion and goblet cell hyperplasia are common features that characterize asthma. IL-13 increases mucin (MUC) 5AC, the major component of airway mucus, in airway epithelial cells. According to the literature, IL-13 receptor activation leads to STAT6 activation and consequent induction of chloride channel accessory 1 (CLCA1) gene expression, associated with the induction of MUC5AC. Heme oxygenase-1 (HO-1) is an enzyme that catalyzes oxidation of heme to biliverdin, and has anti-inflammatory and anti-oxidant properties. We examined the effects of HO-1 on mucin production and goblet cell hyperplasia induced by IL-13. Moreover, we assessed the cell signaling intermediates that appear to be responsible for mucin production. Normal human bronchial epithelial (NHBE) cells were grown at air liquid interface (ALI) in the presence or absence of IL-13 and hemin, a HO-1 inducer, for 14 days. Protein concentration was analyzed using ELISA, and mRNA expression was examined by real-time PCR. Histochemical analysis was performed using HE staining, andWestern blotting was performed to evaluate signaling transduction pathway. Hemin (4 μM) significantly increased HO-1 protein expression (p b 0.01) and HO-1 mRNA expression (p b 0.001). IL-13 significantly increased goblet cells, MUC5AC protein secretion (p b 0.01) and MUC5AC mRNA (p b 0.001), and these were decreased by hemin by way of HO-1. Tin protoporphyrin (SnPP)-IX, a HO-1 inhibitor, blocked the effect of hemin restoring MUC5AC protein secretion (p b 0.05) and goblet cell hyperplasia. Hemin decreased the expression of CLCA1 mRNA (p b 0.05) and it was reversed by SnPP-IX, but could not suppress IL-13-induced phosphorylation of STAT6 or SAM pointed domain-containing ETS transcription factor (SPDEF) and Forkhead box A2 (FOXA2) mRNA expression. In summary, HO-1 overexpression suppressed IL-13-induced goblet cell hyperplasia and MUC5AC production, and involvement of CLCA1 in the mechanism was suggested.

  17. A protein domain interaction interface database: InterPare

    Directory of Open Access Journals (Sweden)

    Lee Jungsul

    2005-08-01

    Full Text Available Abstract Background Most proteins function by interacting with other molecules. Their interaction interfaces are highly conserved throughout evolution to avoid undesirable interactions that lead to fatal disorders in cells. Rational drug discovery includes computational methods to identify the interaction sites of lead compounds to the target molecules. Identifying and classifying protein interaction interfaces on a large scale can help researchers discover drug targets more efficiently. Description We introduce a large-scale protein domain interaction interface database called InterPare http://interpare.net. It contains both inter-chain (between chains interfaces and intra-chain (within chain interfaces. InterPare uses three methods to detect interfaces: 1 the geometric distance method for checking the distance between atoms that belong to different domains, 2 Accessible Surface Area (ASA, a method for detecting the buried region of a protein that is detached from a solvent when forming multimers or complexes, and 3 the Voronoi diagram, a computational geometry method that uses a mathematical definition of interface regions. InterPare includes visualization tools to display protein interior, surface, and interaction interfaces. It also provides statistics such as the amino acid propensities of queried protein according to its interior, surface, and interface region. The atom coordinates that belong to interface, surface, and interior regions can be downloaded from the website. Conclusion InterPare is an open and public database server for protein interaction interface information. It contains the large-scale interface data for proteins whose 3D-structures are known. As of November 2004, there were 10,583 (Geometric distance, 10,431 (ASA, and 11,010 (Voronoi diagram entries in the Protein Data Bank (PDB containing interfaces, according to the above three methods. In the case of the geometric distance method, there are 31,620 inter-chain domain

  18. Designing interfaces patterns for effective interaction design

    CERN Document Server

    Tidwell, Jenifer

    2005-01-01

    This convenient resource offers advice on creating user-friendly interface designs--whether they're delivered on the Web, a CD, or a smart" devices like a cell phone. Solutions to common UI design problems are expressed as a collection of patterns--each one containing concrete examples, recommendations, and warnings. Intended for designers with basic UI design knowledge

  19. Portraying User Interface History

    DEFF Research Database (Denmark)

    Jørgensen, Anker Helms

    2008-01-01

    history at large have been sparse. However, a small spate of publications appeared recently, so a reasonable number of papers are available. Hence this work-in-progress paints a portrait of the current history of user interfaces at large. The paper first describes a theoretical framework recruited from...... 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......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...

  20. 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...

  1. A conservative interface-interaction model with insoluble surfactant

    Science.gov (United States)

    Schranner, Felix S.; Adams, Nikolaus A.

    2016-12-01

    In this paper we extend the conservative interface-interaction method of Hu et al. (2006) [34], adapted for weakly-compressible flows by Luo et al. (2015) [37], to include the effects of viscous, capillary, and Marangoni stresses consistently as momentum-exchange terms at the sharp interface. The interface-interaction method is coupled with insoluble surfactant transport which employs the underlying sharp-interface representation. Unlike previous methods, we thus achieve discrete global conservation in terms of interface interactions and a consistently sharp interface representation. The interface is reconstructed locally, and a sub-cell correction of the interface curvature improves the evaluation of capillary stresses and surfactant diffusion in particular for marginal mesh resolutions. For a range of numerical test cases we demonstrate accuracy and robustness of the method. In particular, we show that the method is at least as accurate as previous diffuse-interface models while exhibiting throughout the considered test cases improved computational efficiency. We believe that the method is attractive for high-resolution level-set interface-tracking simulations as it straightforwardly incorporates the effects of variable surface tension into the underlying conservative interface-interaction approach.

  2. Urban water interfaces

    Science.gov (United States)

    Gessner, M. O.; Hinkelmann, R.; Nützmann, G.; Jekel, M.; Singer, G.; Lewandowski, J.; Nehls, T.; Barjenbruch, M.

    2014-06-01

    Urban water systems consist of large-scale technical systems and both natural and man-made water bodies. The technical systems are essential components of urban infrastructure for water collection, treatment, storage and distribution, as well as for wastewater and runoff collection and subsequent treatment. Urban aquatic ecosystems are typically subject to strong human influences, which impair the quality of surface and ground waters, often with far-reaching impacts on downstream aquatic ecosystems and water users. The various surface and subsurface water bodies in urban environments can be viewed as interconnected compartments that are also extensively intertwined with a range of technical compartments of the urban water system. As a result, urban water systems are characterized by fluxes of water, solutes, gases and energy between contrasting compartments of a technical, natural or hybrid nature. Referred to as urban water interfaces, boundaries between and within these compartments are often specific to urban water systems. Urban water interfaces are generally characterized by steep physical and biogeochemical gradients, which promote high reaction rates. We hypothesize that they act as key sites of processes and fluxes with notable effects on overall system behaviour. By their very nature, urban water interfaces are heterogeneous and dynamic. Therefore, they increase spatial heterogeneity in urban areas and are also expected to contribute notably to the temporal dynamics of urban water systems, which often involve non-linear interactions and feedback mechanisms. Processes at and fluxes across urban water interfaces are complex and less well understood than within well-defined, homogeneous compartments, requiring both empirical investigations and new modelling approaches at both the process and system level. We advocate an integrative conceptual framework of the urban water system that considers interfaces as a key component to improve our fundamental

  3. Semiconductor Oxide Interface States.

    Science.gov (United States)

    1981-05-01

    0C for 30 minutes. B 9 7 and B17 curves were taken before forming gas annealing and A297 and A77 were taken after annealing in forming gas... A297 and A77’ AL .show a substantial reduction of interface states and a slight increase of positive oxide charges. The reduction of the interface...states is deduced from the voltage differences between A297 and the A77 C-V curves both above and below the cross-over point which are smaller than the

  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. 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.

  6. 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.

  7. 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.

  8. Introduction to diffuse interfaces and transformation fronts modelling in compressible media

    OpenAIRE

    Saurel Richard; Petitpas Fabien

    2013-01-01

    Computation of interfaces separating compressible materials is related to mixture cells appearance. These mixture cells are consequences of fluid motion and artificial smearing of discontinuities. The correct computation of the entire flow field requires perfect fulfillment of the interface conditions. In the simplest situation of contact interfaces with perfect fluids, these conditions correspond to equal normal velocities and equal pressures. To compute compressible flows with interfac...

  9. User interface design considerations

    DEFF Research Database (Denmark)

    Andersen, Simon Engedal; Jakobsen, Arne; Rasmussen, Bjarne D.

    1999-01-01

    When designing a user interface for a simulation model there are several important issues to consider: Who is the target user group, and which a priori information can be expected. What questions do the users want answers to and what questions are answered using a specific model?When developing...

  10. 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...

  11. Photochemistry at Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Eisenthal, Kenneth B [Columbia Univ., New York, NY (United States)

    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.

  12. 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.

  13. Observations of a monotectic solidification interface morphology

    Science.gov (United States)

    Kaukler, W. F.; Frazier, D. O.

    1985-01-01

    For detailed studies of the region around a solidification interface on a microscopic scale, a very thin (essentially two-dimensional) test cell may be translated across two temperature-controlled heating/cooling blocks and viewed with a microscope. Such a device is sometimes referred to as a temperature gradient microscope stage (TGS). Of particular interest in this study is the behavior of a monotectic type solution during solidification. Succinonitrile based model systems for metallic monotectic alloys, when solidified on a TGS, form an unusual 'worm-like' micromorphology. These interfaces are observable in situ under high optical magnification during growth.

  14. Tissue-engineered skin preserving the potential of epithelial cells to differentiate into hair after grafting.

    Science.gov (United States)

    Larouche, Danielle; Cuffley, Kristine; Paquet, Claudie; Germain, Lucie

    2011-03-01

    The aim of this study was to evaluate whether tissue-engineered skin produced in vitro was able to sustain growth of hair follicles in vitro and after grafting. Different tissues were designed. Dissociated newborn mouse keratinocytes or newborn mouse hair buds (HBs) were added onto dermal constructs consisting of a tissue-engineered cell-derived matrix elaborated from either newborn mouse or adult human fibroblasts cultured with ascorbic acid. After 7-21 days of maturation at the air-liquid interface, no hair was noticed in vitro. Epidermal differentiation was observed in all tissue-engineered skin. However, human fibroblast-derived tissue-engineered dermis (hD) promoted a thicker epidermis than mouse fibroblast-derived tissue-engineered dermis (mD). In association with mD, HBs developed epithelial cyst-like inclusions presenting outer root sheath-like attributes. In contrast, epidermoid cyst-like inclusions lined by a stratified squamous epithelium were present in tissues composed of HBs and hD. After grafting, pilo-sebaceous units formed and hair grew in skin elaborated from HBs cultured 10-26 days submerged in culture medium in association with mD. However, the number of normal hair follicles decreased with longer culture time. This hair-forming capacity after grafting was not observed in tissues composed of hD overlaid with HBs. These results demonstrate that epithelial stem cells can be kept in vitro in a permissive tissue-engineered dermal environment without losing their potential to induce hair growth after grafting.

  15. 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.

  16. Charge transfer and recombination at the metal oxide/CH3NH3PbClI2/spiro-OMeTAD interfaces: uncovering the detailed mechanism behind high efficiency solar cells.

    Science.gov (United States)

    Shen, Qing; Ogomi, Yuhei; Chang, Jin; Tsukamoto, Syota; Kukihara, Kenji; Oshima, Takuya; Osada, Naoya; Yoshino, Kenji; Katayama, Kenji; Toyoda, Taro; Hayase, Shuzi

    2014-10-07

    In recent years, organometal halide perovskite-based solid-state hybrid solar cells have attracted unexpected increasing interest because of their high efficiency (the record power conversion efficiency has been reported to be over 15%) and low fabrication cost. It has been accepted that the high efficiency was mainly attributed to the strong optical absorption (absorption coefficient: 15,000 cm(-1) at 550 nm) over a broader range (up to 800 nm) and the long lifetimes of photoexcited charge carriers (in the order of 10 ns - a few 100 ns) of the perovskite absorbers. However, much of the fundamental photophysical properties of perovskite relating to the high photovoltaic performance are remained to be investigated. The charge separation and recombination processes at the material interfaces are particularly important for solar cell performances. To better understand the high efficiency of perovskite solar cells, we systematically investigated the charge separation (electron and hole injection) and charge recombination dynamics of CH3NH3PbClI2 hybrid solar cells employing TiO2 nanostructures as the electron transfer material (ETM) and spiro-OMeTAD as the hole transfer material (HTM). The measurements were carried out using transient absorption (TA) techniques on a time scale from sub-picoseconds to milliseconds. We clarified the timescales of electron injection, hole injection, and recombination processes in TiO2/CH3NH3PbClI2/spiro-OMeTAD solar cells. Charge separation and collection efficiency of the perovskite-based solar cells were discussed. In addition, the effect of TiO2 size on the charge separation and recombination dynamics was also investigated. It was found that all TiO2-based perovskite solar cells possessed similar charge separation processes, but quite different recombination dynamics. Our results indicate that charge recombination was crucial to the performance of the perovskite solar cells, which could be effectively suppressed through optimising

  17. 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.

  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. 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.

  20. Dynamic actuation using nano-bio interfaces

    Directory of Open Access Journals (Sweden)

    Ian Y. Wong

    2010-06-01

    Full Text Available The nanoscale dimensions, sensitive electronic control, and flexible architecture of new generations of nanomaterials and nanofabrication techniques hold immense promise not only for electronic devices, but also biological interfaces. As the size scales of these materials approach biological species, interfaces with characteristics designed to emulate their nanoscale biological counterparts are becoming possible. These new systems have higher biocompatibility, functionality, and lower cell toxicity than their microscale predecessors. While stellar examples have been demonstrated for biomolecular detection and imaging, exciting new possibilities for long-term integration and dynamic stimulation are now emerging, including protein activation, membrane integration and intracellular delivery. These tailored interfaces may lead to improved regenerative medicine, gene therapy and neural prosthetics.

  1. Apple cuticle: the perfect interface

    Science.gov (United States)

    Curry, Eric; Arey, Bruce

    2010-06-01

    The domestic apple might well be called an 'extreme' fruit. In the arid Northwest United States, the fruit often tolerates surface temperatures ranging from -2 °C in the early spring to 50 °C in the heat of summer, and again to -2 °C during controlled postharvest storage for up to 12 months. During its 18-month existence, the apple maintains a cuticle that is dynamic and environmentally responsive to protect against 1) cellular water loss during desiccation stress and 2) excessive uptake of standing surface moisture. Physiological disorders of the peel such as russeting, cracking, splitting, flecking and lenticel marking, develop as epidermal cells respond to rapid changes in ambient conditions at specific developmental stages during the growing season. Resultant market losses underlie research investigating the nature of apple cuticle growth and development. Ultrastructural analysis of the pro-cuticle using scanning electron microscopy indicates an overlapping network of lipid-based distally-elongating microtubules--produced by and connected to epidermal cells--which co-polymerize to form an organic solvent-insoluble semi-permeable cutin matrix. Microtubule elongation, aggregation, and polymerization function together as long as the fruit continues to enlarge. The nature of lipid transport from the epidermal cells through the cell wall to become part of the cuticular matrix was explored using an FEI Helios NanoLabTM DualBeamTM focused ion beam/scanning electron microscope on chemically- and cryo-fixed peel tissue from mature or freshly harvested apples. Based on microtubule dimensions, regular projections found at the cell/cuticle interface suggest an array of microtubule-like structures associated with the epidermal cell.

  2. 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

  3. 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.

  4. 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.

  5. Popeye Project: ROV interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Scates, C.R. [Shell Oil Inc., New Orleans, LA (United States); Hickok, D.D. [Dvaerner FSSL Inc., Houston, TX (United States); Hernandez, D.A.

    1997-04-01

    The Popeye Project in the Gulf of Mexico helped advance the technology and standardization of ROV interfaces for deepwater subsea production systems. Some of the many successful ROV operations during installation and completion were {open_quotes}first-of-it`s-kind{close_quotes} activities-enabled by many technical advances. The use and reliance upon ROV systems for support of deepwater drilling and installation operations significantly increased in the past 10 years. Shell Offshore Inc.`s (SOI) confidence in this increased capability was an important factor in many of the design decisions which characterized the innovative system. Technology advancements, which depended on effective ROV intervention, were implemented with no significant difficulties. These advancements, in particular the flying leads and seabed position methods, are available to the industry for other deepwater subsea systems. In addition, several Popeye ROV interfaces have helped advance the subsea standardization initiative; e.g., hot stabs, torque-tool end effectors, and paint color.

  6. 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...

  7. An Approach to Interface Synthesis

    DEFF Research Database (Denmark)

    Madsen, Jan; Hald, Bjarne

    1995-01-01

    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......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......-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....

  8. 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.

  9. Noise at the Interface

    DEFF Research Database (Denmark)

    Prior, Andrew

    2011-01-01

    The notion of noise occupies a contested territory, in which it is framed as pollution and detritus even as it makes its opposite a possibility - noise is always defined in opposition to something else, even if this ‘other’ is not quite clear. This paper explores noise in the context of ‘the...... interface’ asking what its affordances as an idea may contribute to our understanding of interface. I draw historically on information theory in particular to initiate this exploration....

  10. Microsystem Interfaces for Space

    OpenAIRE

    2006-01-01

    Microsystem interfaces to the macroscopic surroundings and within the microsystems themselves are formidable challenges that this thesis makes an effort to overcome, specifically for enabling a spacecraft based entirely on microsystems. The NanoSpace-1 nanospacecraft is a full-fledged satellite design with mass below 10 kg. The high performance with respect to mass is enabled by a massive implementation of microsystem technology – the entire spacecraft structure is built from square silicon p...

  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. Electrokinetics of heterogeneous interfaces.

    Science.gov (United States)

    Zembala, Maria

    2004-12-31

    The influence of surface heterogeneity of various types on electrokinetic parameters is reviewed. The scope of the paper covers classical electrokinetic phenomena characterized by linear dependence of electrokinetic parameters vs. related driving forces. Neither non-linear effects nor the effects of non-equilibrium electric double layer are considered. A historical description of hydrodynamic aspect of electrokinetic phenomena exploiting the slip plane idea is briefly outlined. Attempts to estimate the slip plane location by comparing the diffuse layer and zeta potential values for some model systems are presented. The surface heterogeneity was divided into three categories. Heterogeneity of the first type was related to geometrical morphology of an interfacial region characterized by a considerable surface development producing a three-dimensional interfacial region. The effects of solid roughness, hairy surface, dense polymer layers and gel-like layers are discussed here. The very high surface conductivity detected for such interfaces seems to be a good indicator of the presence of structured layers of this type. Heterogeneous interfaces of the second class cover systems exhibiting non-uniform distribution of surface charge. The non-uniform surface charge distribution can be either of a molecular (discrete charges) or of a microscale (two-dimensional micropatches or three-dimensional structures formed by polyelectrolyte multilayers). The last class of systems examined includes interfaces composed of charged substrate covered by charged bulky objects (particles). In comparison to the homogeneous surfaces, adsorbed charged particles modify both hydrodynamic flow and the electrostatic field significantly altering the electrokinetic parameters. The new description of electrokinetics of composed interfaces presented here takes into account both hydrodynamic and electric field modification and is free of the previously assumed slip plane shift caused by adsorbed

  13. 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.

  14. The Role of LORELEI in Pollen Tube Reception at the Interface of the Synergid Cell and Pollen Tube Requires the Modified Eight-Cysteine Motif and the Receptor-Like Kinase FERONIA.

    Science.gov (United States)

    Liu, Xunliang; Castro, Claudia; Wang, Yanbing; Noble, Jennifer; Ponvert, Nathaniel; Bundy, Mark; Hoel, Chelsea; Shpak, Elena; Palanivelu, Ravishankar

    2016-05-01

    In angiosperms, pollen tube reception by the female gametophyte is required for sperm release and double fertilization. In Arabidopsis thaliana lorelei (lre) mutants, pollen tube reception fails in most female gametophytes, which thus remain unfertilized. LRE encodes a putative glycosylphosphatidylinositol (GPI)-anchored surface protein with a modified eight-cysteine motif (M8CM). LRE fused to citrine yellow fluorescent protein (LRE-cYFP) remains functional and localizes to the synergid plasma membrane-rich filiform apparatus, the first point of contact between the pollen tube and the female gametophyte. Structure-function analysis using LRE-cYFP showed that the role of LRE in pollen tube reception requires the M8CM, but not the domains required for GPI anchor addition. Consistently, LRE-cYFP-TM, where GPI anchor addition domains were replaced with a single-pass transmembrane domain, fully complemented the pollen tube reception defect in lre-7 female gametophytes. Ectopically expressed and delivered LRE-cYFP from pollen tubes could non-cell-autonomously complement the pollen tube reception defect in lre female gametophytes, only if they expressed FERONIA. Additionally, pollen tube-expressing LRE variants lacking domains critical for GPI anchor addition also rescued lre female gametophyte function. Therefore, LRE and FERONIA jointly function in pollen tube reception at the interface of the synergid cell and pollen tube.

  15. Multilayer Dye Aggregation at Dye/TiO2 Interface via π…π Stacking and Hydrogen Bond and Its Impact on Solar Cell Performance: A DFT Analysis

    Science.gov (United States)

    Zhang, Lei; Liu, Xiaogang; Rao, Weifeng; Li, Jingfa

    2016-10-01

    Multilayer dye aggregation at the dye/TiO2 interface of dye-sensitized solar cells is probed via first principles calculations, using p-methyl red azo dye as an example. Our calculations suggest that the multilayer dye aggregates at the TiO2 surface can be stabilized by π…π stacking and hydrogen bond interactions. Compared with previous two-dimensional monolayer dye/TiO2 model, the multilayer dye aggregation model proposed in this study constructs a three-dimensional multilayer dye/TiO2 interfacial structure, and provides a better agreement between experimental and computational results in dye coverage and dye adsorption energy. In particular, a dimer forms by π…π stacking interactions between two neighboring azo molecules, while one of them chemisorbs on the TiO2 surface; a trimer may form by introducing one additional azo molecule on the dimer through a hydrogen bond between two carboxylic acid groups. Different forms of multilayer dye aggregates, either stabilized by π…π stacking or hydrogen bond, exhibit varied optical absorption spectra and electronic properties. Such variations could have a critical impact on the performance of dye sensitized solar cells.

  16. 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

  17. Interface Input/Output Automata

    DEFF Research Database (Denmark)

    Larsen, Kim Guldstrand; Nyman, Ulrik; Wasowski, Andrzej

    2006-01-01

    Building on the theory of interface automata by de Alfaro and Henzinger we design an interface language for Lynch’s I/O, a popular formalism used in the development of distributed asynchronous systems, not addressed by previous interface research. We introduce an explicit separation of assumption...

  18. Effect of pre-cleaning treatment and contact wetting angle in the interface between P-doped Si surfaces and selective solar cell electrodes

    Science.gov (United States)

    Cui, Yinhua; Choi, Eunmi; Kim, Areum; Oh, Leeseul; Lee, Seon Jea; Ryang, Ayeon; Park, Hansoo; Lim, Kyunghee; Pyo, Sung Gyu

    2013-07-01

    Prior to electroless plating of the solar cell electrode, the sample was cleaned with a mixture of a sulfuric acid and peroxide solution and a H2NCH2CH2CH2Si(OC2H5) solution. We measured the de-wetting and contact angles of the solar cell thin film electrode. After SPM and APTES treatments, an excellent hydrophilic contact angle was observed. Our results show that it is more effective to remove oxidizer with SiO2 than HF mixed solutions. When comparing the efficiency, pre-treatment with a NH4F:HF mixed solution was more efficient than pre-treatment with a diluted HF solution. After NH4F:HF mixed solution cleaning, when the electrode was formed, the contact resistance that most directly affected the cleaning effect was 0.8194 ohm/sq, which had three times more improvement effect. It is expected that if an optimum cleaning time and process conditions for each cleaning chemical is developed, more improved contact resistance will be secured when each cleaning chemical is applied.

  19. A computational method for sharp interface advection

    Science.gov (United States)

    Roenby, Johan; Bredmose, Henrik; Jasak, Hrvoje

    2016-11-01

    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 of 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 two-dimensional and three-dimensional interface advection problems on both structured and unstructured meshes. The results are very satisfactory in terms of volume conservation, boundedness, surface sharpness and efficiency. The isoAdvector method was implemented as an OpenFOAM extension and is published as open source.

  20. 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 ...

  1. Radial fingering at an active interface

    Science.gov (United States)

    Nagilla, Amarender; Prabhakar, Ranganathan; Jadhav, Sameer

    2016-11-01

    It has been suggested that the shapes of single cells crawling on surfaces and those of the fronts of thin layers of cells collectively expanding to close a wound are the results of fingering instabilities. Motivated by these studies, we investigate the conditions under which an actively forced interface between a pair of immiscible viscous fluids will destabilize under Hele-Shaw confinement. The case of a circular active interface with surface tension and bending resistance is considered. Active forces exerted by the inner fluid at the interfacial region can be either completely internal or due to interactions with the confining substrate. In addition, the effects of cell growth or actin depolymerization or external injection of cell suspensions are modeled by including a distributed source and a point source of arbitrary strengths. Linear stability analysis reveals that at any given mean radius of the interface, its stability is dictated by two key dimensionless parameters. We discuss the different regions in a state space of these parameters.

  2. The interaction of mefloquine hydrochloride with cell membrane models at the air-water interface is modulated by the monolayer lipid composition.

    Science.gov (United States)

    Goto, Thiago Eichi; Caseli, Luciano

    2014-10-01

    The antiparasitic properties of antiparasitic drugs are believed to be associated with their interactions with the protozoan membrane, encouraging research on the identification of membrane sites capable of drug binding. In this study, we investigated the interaction of mefloquine hydrochloride, known to be effective against malaria, with cell membrane models represented by Langmuir monolayers of selected lipids. It is shown that even small amounts of the drug affect the surface pressure-area isotherms as well as surface vibrational spectra of some lipid monolayers, which points to a significant interaction. The effects on the latter depend on the electrical charge of the monolayer-forming molecules, with the drug activity being particularly distinctive for negatively charged lipids. Therefore, the lipid composition of the monolayer modulates the interaction with the lipophilic drug, which may have important implications in understanding how the drug acts on specific sites of the protozoan membrane.

  3. Interface-Induced High-Temperature Superconductivity in Single Unit-Cell FeSe Films on SrTiO3

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-Yan; CHANG Kai; WEN Jing; SONG Can-Li; HE Ke; JIA Jin-Feng; JI Shuai-Hua; WANG Ya-Yu; WANG Li-Li; CHEN Xi; MA Xu-Cun; LI Zhi; XUE Qi-Kun; ZHANG Wen-Hao; ZHANG Zuo-Cheng; ZHANG Jin-Song; LI Wei; DING Hao; OU Yun-Bo; DENG Peng

    2012-01-01

    We report high transition temperature superconductivity in one unit-cell (UC) thick FeSe films grown on a Seetched SrTiO3 (001) substrate by molecular beam epitaxy (MBE).A superconducting gap as large as 20 meV and the magnetic field induced vortex state revealed by in situ scanning tunneling microscopy (STM) suggest that the superconductivity of the 1 UC FeSe films could occur around 77K.The control transport measurement shows that the onset superconductivity temperature is well above 50K.Our work not only demonstrates a powerful way for finding new superconductors and for raising Tc,but also provides a well-defined platform for systematic studies of the mechanism of unconventional superconductivity by using different superconducting materials and substrates.

  4. Single-interface Casimir torque

    Science.gov (United States)

    Morgado, Tiago A.; Silveirinha, Mário G.

    2016-10-01

    A different type of Casimir-type interaction is theoretically predicted: a single-interface torque at a junction of an anisotropic material and a vacuum or another material system. The torque acts to reorient the polarizable microscopic units of the involved materials near the interface, and thus to change the internal structure of the materials. The single-interface torque depends on the zero-point energy of the interface localized and extended modes. Our theory demonstrates that the single-interface torque is essential to understand the Casimir physics of material systems with anisotropic elements and may influence the orientation of the director of nematic liquid crystals.

  5. 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

  6. Conceptual Framework for Aquatic Interfaces

    Science.gov (United States)

    Lewandowski, J.; Krause, S.

    2015-12-01

    Aquatic interfaces are generally characterized by steep gradients of physical, chemical and biological properties due to the contrast between the two adjacent environments. Innovative measurement techniques are required to study the spatially heterogeneous and temporally variable processes. Especially the different spatial and temporal scales are a large challenge. Due to the steep biogeochemical gradients and the intensive structural and compositional heterogeneity, enhanced biogeochemical processing rates are inherent to aquatic interfaces. Nevertheless, the effective turnover depends strongly on the residence time distribution along the flow paths and in sections with particular biogeochemical milieus and reaction kinetics. Thus, identification and characterization of the highly complex flow patterns in and across aquatic interfaces are crucial to understand biogeochemical processing along exchange flow paths and to quantify transport across aquatic interfaces. Hydrodynamic and biogeochemical processes are closely coupled at aquatic interfaces. However, interface processing rates are not only enhanced compared to the adjacent compartments that they connect; also completely different reactions might occur if certain thresholds are exceeded or the biogeochemical milieu differs significantly from the adjacent environments. Single events, temporal variability and spatial heterogeneity might increase overall processing rates of aquatic interfaces and thus, should not be neglected when studying aquatic interfaces. Aquatic interfaces are key zones relevant for the ecological state of the entire ecosystem and thus, understanding interface functioning and controls is paramount for ecosystem management. The overall aim of this contribution is a general conceptual framework for aquatic interfaces that is applicable to a wide range of systems, scales and processes.

  7. Matched Interface and Boundary Method for Elasticity Interface Problems

    Science.gov (United States)

    Wang, Bao; Xia, Kelin; Wei, Guo-Wei

    2015-01-01

    Elasticity theory is an important component of continuum mechanics and has had widely spread applications in science and engineering. Material interfaces are ubiquity in nature and man-made devices, and often give rise to discontinuous coefficients in the governing elasticity equations. In this work, the matched interface and boundary (MIB) method is developed to address elasticity interface problems. Linear elasticity theory for both isotropic homogeneous and inhomogeneous media is employed. In our approach, Lamé’s parameters can have jumps across the interface and are allowed to be position dependent in modeling isotropic inhomogeneous material. Both strong discontinuity, i.e., discontinuous solution, and weak discontinuity, namely, discontinuous derivatives of the solution, are considered in the present study. In the proposed method, fictitious values are utilized so that the standard central finite different schemes can be employed regardless of the interface. Interface jump conditions are enforced on the interface, which in turn, accurately determines fictitious values. We design new MIB schemes to account for complex interface geometries. In particular, the cross derivatives in the elasticity equations are difficult to handle for complex interface geometries. We propose secondary fictitious values and construct geometry based interpolation schemes to overcome this difficulty. Numerous analytical examples are used to validate the accuracy, convergence and robustness of the present MIB method for elasticity interface problems with both small and large curvatures, strong and weak discontinuities, and constant and variable coefficients. Numerical tests indicate second order accuracy in both L∞ and L2 norms. PMID:25914439

  8. Brain-computer interface

    DEFF Research Database (Denmark)

    2014-01-01

    A computer-implemented method of providing an interface between a user and a processing unit, the method comprising : presenting one or more stimuli to a user, each stimulus varying at a respective stimulation frequency, each stimulation frequency being associated with a respective user......-selectable input; receiving at least one signal indicative of brain activity of the user; and determining, from the received signal, which of the one or more stimuli the user attends to and selecting the user-selectable input associated with the stimulation frequency of the determined stimuli as being a user...

  9. 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 pa....... 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....

  10. 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...

  11. 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

  12. 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.

  13. 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.

  14. Differential responses of healthy and chronic obstructive pulmonary diseased human bronchial epithelial cells repeatedly exposed to air pollution-derived PM4.

    Science.gov (United States)

    Leclercq, B; Happillon, M; Antherieu, S; Hardy, E M; Alleman, L Y; Grova, N; Perdrix, E; Appenzeller, B M; Lo Guidice, J-M; Coddeville, P; Garçon, G

    2016-11-01

    While the knowledge of the underlying mechanisms by which air pollution-derived particulate matter (PM) exerts its harmful health effects is still incomplete, detailed in vitro studies are highly needed. With the aim of getting closer to the human in vivo conditions and better integrating a number of factors related to pre-existing chronic pulmonary inflammatory, we sought to develop primary cultures of normal human bronchial epithelial (NHBE) cells and chronic obstructive pulmonary disease (COPD)-diseased human bronchial epithelial (DHBE) cells, grown at the air-liquid interface. Pan-cytokeratin and MUC5AC immunostaining confirmed the specific cell-types of both these healthy and diseased cell models and showed they are closed to human bronchial epithelia. Thereafter, healthy and diseased cells were repeatedly exposed to air pollution-derived PM4 at the non-cytotoxic concentration of 5 μg/cm(2). The differences between the oxidative and inflammatory states in non-exposed NHBE and COPD-DHBE cells indicated that diseased cells conserved their specific physiopathological characteristics. Increases in both oxidative damage and cytokine secretion were reported in repeatedly exposed NHBE cells and particularly in COPD-DHBE cells. Diseased cells repeatedly exposed had lower capacities to metabolize the organic chemicals-coated onto the air-pollution-derived PM4, such as benzo[a]pyrene (B[a]P), but showed higher sensibility to the formation of OH-B[a]P DNA adducts, because their diseased state possibly affected their defenses. Differential profiles of epigenetic hallmarks (i.e., global DNA hypomethylation, P16 promoter hypermethylation, telomere length shortening, telomerase activation, and histone H3 modifications) occurred in repeatedly exposed NHBE and particularly in COPD-DHBE cells. Taken together, these results closely supported the highest responsiveness of COPD-DHBE cells to a repeated exposure to air pollution-derived PM4. The use of these innovative in

  15. Metabolic detoxication pathways for sterigmatocystin in primary tracheal epithelial cells.

    Science.gov (United States)

    Cabaret, Odile; Puel, Olivier; Botterel, Françoise; Pean, Michel; Khoufache, Khaled; Costa, Jean-Marc; Delaforge, Marcel; Bretagne, Stéphane

    2010-11-15

    Human health effects of inhaled mycotoxins remain poorly documented, despite the large amounts present in bioaerosols. Among these mycotoxins, sterigmatocystin is one of the most prevalent. Our aim was to study the metabolism and cellular consequences of sterigmatocystin once it is in contact with the airway epithelium. Metabolites were analyzed first in vitro, using recombinant P450 1A1, 1A2, 2A6, 2A13, and 3A4 enzymes, and subsequently in porcine tracheal epithelial cell (PTEC) primary cultures at an air-liquid interface. Expressed enzymes and PTECs were exposed to sterigmatocystin, uniformly enriched with (13)C to confirm the relationship between sterigmatocystin and metabolites. Induction of the expression of xenobiotic-metabolizing enzymes upon sterigmatocystin exposure was examined by real-time quantitative real-time polymerase chain reaction. Incubation of 50 μM sterigmatocystin with recombinant P450 1A1 led to the formation of three metabolites: monohydroxy-sterigmatocystin (M1), dihydroxy-sterigmatocystin (M2), and one glutathione adduct (M3), the latter after the formation of a transient epoxide. Recombinant P450 1A2 also led to M1 and M3. P450 3A4 led to only M3. In PTEC, 1 μM sterigmatocystin metabolism resulted in a glucuro conjugate (M4) mainly excreted at the basal side of cells. If PTEC were treated with β-naphthoflavone prior to sterigmatocystin incubation, two other products were detected, i.e., a sulfo conjugate (M5) and a glucoro conjugate (M6) of hydroxy-sterigmatocystin. Exposure of PTEC for 24 h to 1 μM sterigmatocystin induced an 18-fold increase in the mRNA levels of P450 1A1, without significantly induced 7-ethoxyresorufin O-deethylation activity. These data suggest that sterigmatocystin is mainly detoxified and is unable to produce significant amounts of reactive epoxide metabolites in respiratory cells. However, sterigmatocystin increases the P450 1A1 mRNA levels with unknown long-term consequences. These in vitro results obtained in

  16. 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.

  17. Laparoscopic simulation interface

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Flexible DCP interface. [environmental sensor and signal conditioning interface

    Science.gov (United States)

    Kanemasu, E. T.; Schimmelpfenning, H.

    1974-01-01

    The author has identified the following significant results. A user of an ERTS data collection system (DCS) must supply the sensors and signal-conditioning interface. The electronic interface must be compatible with the NASA-furnished data collection platform. A universal signal-conditioning system for use with a wide range of environmental sensors is described. The interface is environmentally and electronically compatible with the DCP and has operated satisfactorily for a complete winter wheat growing season in Kansas.

  19. 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.

  20. Understanding Interfaces in Metal-Graphitic Hybrid Nanostructures”

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Mengning; Tang, Yifan; Star, Alexander

    2013-01-03

    Metal–graphitic interfaces formed between metal nanoparticles (MNPs) and carbon nanotubes (CNTs) or graphene play an important role in the properties of such hybrid nanostructures. This Perspective summarizes different types of interfaces that exist within the metal–carbon nanoassemblies and discusses current efforts on understanding and modeling the interfacial conditions and interactions. Characterization of the metal–graphitic interfaces is described here, including microscopy, spectroscopy, electrochemical techniques, and electrical measurements. Recent studies on these nanohybrids have shown that the metal–graphitic interfaces play critical roles in both controlled assembly of nanoparticles and practical applications of nanohybrids in chemical sensors and fuel cells. Better understanding, design, and manipulation of metal–graphitic interfaces could therefore become the new frontier in the research of MNP/CNT or MNP/graphene hybrid systems.

  1. 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

  2. Proceedings Foundations for Interface Technologies

    CERN Document Server

    Legay, Axel; 10.4204/EPTCS.46

    2011-01-01

    FIT stands for Foundations of Interface Technologies. Component-based design is widely considered as a major approach to developing systems in a time and cost effective way. Central in this approach is the notion of an interface. Interfaces summarize the externally visible properties of a component and are seen as a key to achieving component interoperability and to predict global system behavior based on the component behavior. To capture the intricacy of complex software products, rich interfaces have been proposed. These interfaces do not only specify syntactic properties, such as the signatures of methods and operations, but also take into account behavioral and extra-functional properties, such as quality of service, security and dependability. Rich interfaces have been proposed for describing, e.g., the legal sequences of messages or method calls accepted by components, or the resource and timing constraints in embedded software. The development of a rigorous framework for the specification and analysis...

  3. 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.

  4. Distinctive glial and neuronal interfacing on nanocrystalline diamond.

    Science.gov (United States)

    Bendali, Amel; Agnès, Charles; Meffert, Simone; Forster, Valérie; Bongrain, Alexandre; Arnault, Jean-Charles; Sahel, José-Alain; Offenhäusser, Andreas; Bergonzo, Philippe; Picaud, Serge

    2014-01-01

    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.

  5. Distinctive Glial and Neuronal Interfacing on Nanocrystalline Diamond

    Science.gov (United States)

    Bendali, Amel; Agnès, Charles; Meffert, Simone; Forster, Valérie; Bongrain, Alexandre; Arnault, Jean-Charles; Sahel, José-Alain; Offenhäusser, Andreas; Bergonzo, Philippe; Picaud, Serge

    2014-01-01

    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. PMID:24664111

  6. 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...

  7. Porphyrins at interfaces

    Science.gov (United States)

    Auwärter, Willi; Écija, David; Klappenberger, Florian; Barth, Johannes V.

    2015-02-01

    Porphyrins and other tetrapyrrole macrocycles possess an impressive variety of functional properties that have been exploited in natural and artificial systems. Different metal centres incorporated within the tetradentate ligand are key for achieving and regulating vital processes, including reversible axial ligation of adducts, electron transfer, light-harvesting and catalytic transformations. Tailored substituents optimize their performance, dictating their arrangement in specific environments and mediating the assembly of molecular nanoarchitectures. Here we review the current understanding of these species at well-defined interfaces, disclosing exquisite insights into their structural and chemical properties, and also discussing methods by which to manipulate their intramolecular and organizational features. The distinct characteristics arising from the interfacial confinement offer intriguing prospects for molecular science and advanced materials. We assess the role of surface interactions with respect to electronic and physicochemical characteristics, and describe in situ metallation pathways, molecular magnetism, rotation and switching. The engineering of nanostructures, organized layers, interfacial hybrid and bio-inspired systems is also addressed.

  8. 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.

  9. A note on charged interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Luo Huaqiang [Courant Institute of Mathematical Sciences, New York University, New York, NY 10012 (United States); Yu, M Y [Institute for Theoretical Physics I, Ruhr-University, D-44780 Bochum (Germany)

    2006-12-15

    A condition associated with the plasma boundary or other charged interface is reviewed. It is pointed out that in comparing theories and simulations of such interfaces, in order to avoid conflicting results it should be ascertained that the systems under consideration are thermodynamically equivalent. For the plasma-wall interface in equilibrium, the rate of change of the surface-charge density with respect to the surface potential must be positive.

  10. Intelligent interface design and evaluation

    Science.gov (United States)

    Greitzer, Frank L.

    1988-01-01

    Intelligent interface concepts and systematic approaches to assessing their functionality are discussed. Four general features of intelligent interfaces are described: interaction efficiency, subtask automation, context sensitivity, and use of an appropriate design metaphor. Three evaluation methods are discussed: Functional Analysis, Part-Task Evaluation, and Operational Testing. Design and evaluation concepts are illustrated with examples from a prototype expert system interface for environmental control and life support systems for manned space platforms.

  11. Capillary flows with forming interfaces

    CERN Document Server

    Shikhmurzaev, Yulii D

    2007-01-01

    PREFACEINTRODUCTION Free-surface flows in nature and industryScope of the bookFUNDAMENTALS OF FLUID MECHANICS Main concepts Governing equations Elements of thermodynamics Classical boundary conditions Physically meaningful solutions and paradoxes of modelingMOVING CONTACT LINES: AN OVERVIEW Essence of the problem Experimental observations Molecular dynamics simulations Review of theoriesThe key to the moving contact-line problemBOUNDARY CONDITIONS ON FORMING INTERFACES Modeling of interfacesConservation lawsLiquid-gas and liquid-solid interfacesLiquid-liquid interfaces SummaryOpen questions an

  12. Interface-assisted molecular spintronics

    Energy Technology Data Exchange (ETDEWEB)

    Raman, Karthik V. [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012 (India)

    2014-09-15

    Molecular spintronics, a field that utilizes the spin state of organic molecules to develop magneto-electronic devices, has shown an enormous scientific activity for more than a decade. But, in the last couple of years, new insights in understanding the fundamental phenomena of molecular interaction on magnetic surfaces, forming a hybrid interface, are presenting a new pathway for developing the subfield of interface-assisted molecular spintronics. The recent exploration of such hybrid interfaces involving carbon based aromatic molecules shows a significant excitement and promise over the previously studied single molecular magnets. In the above new scenario, hybridization of the molecular orbitals with the spin-polarized bands of the surface creates new interface states with unique electronic and magnetic character. This study opens up a molecular-genome initiative in designing new handles to functionalize the spin dependent electronic properties of the hybrid interface to construct spin-functional tailor-made devices. Through this article, we review this subject by presenting a fundamental understanding of the interface spin-chemistry and spin-physics by taking support of advanced computational and spectroscopy tools to investigate molecular spin responses with demonstration of new interface phenomena. Spin-polarized scanning tunneling spectroscopy is favorably considered to be an important tool to investigate these hybrid interfaces with intra-molecular spatial resolution. Finally, by addressing some of the recent findings, we propose novel device schemes towards building interface tailored molecular spintronic devices for applications in sensor, memory, and quantum computing.

  13. Apical Localization of Zinc Transporter ZnT4 in Human Airway Epithelial Cells and Its Loss in a Murine Model of Allergic Airway Inflammation

    Directory of Open Access Journals (Sweden)

    Chiara Murgia

    2011-10-01

    Full Text Available The apical cytoplasm of airway epithelium (AE contains abundant labile zinc (Zn ions that are involved in the protection of AE from oxidants and inhaled noxious substances. A major question is how dietary Zn traffics to this compartment. In rat airways, in vivo selenite autometallographic (Se-AMG-electron microscopy revealed labile Zn-selenium nanocrystals in structures resembling secretory vesicles in the apical cytoplasm. This observation was consistent with the starry-sky Zinquin fluorescence staining of labile Zn ions confined to the same region. The vesicular Zn transporter ZnT4 was likewise prominent in both the apical and basal parts of the epithelium both in rodent and human AE, although the apical pools were more obvious. Expression of ZnT4 mRNA was unaffected by changes in the extracellular Zn concentration. However, levels increased 3-fold during growth of cells in air liquid interface cultures and decreased sharply in the presence of retinoic acid. When comparing nasal versus bronchial human AE cells, there were significant positive correlations between levels of ZnT4 from the same subject, suggesting that nasal brushings may allow monitoring of airway Zn transporter expression. Finally, there were marked losses of both basally-located ZnT4 protein and labile Zn in the bronchial epithelium of mice with allergic airway inflammation. This study is the first to describe co-localization of zinc vesicles with the specific zinc transporter ZnT4 in airway epithelium and loss of ZnT4 protein in inflamed airways. Direct evidence that ZnT4 regulates Zn levels in the epithelium still needs to be provided. We speculate that ZnT4 is an important regulator of zinc ion accumulation in secretory apical vesicles and that the loss of labile Zn and ZnT4 in airway inflammation contributes to AE vulnerability in diseases such as asthma.

  14. 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%.

  15. Playful user interfaces: interfaces that invite social and physical interaction

    NARCIS (Netherlands)

    Nijholt, Anton

    2014-01-01

    This book is about user interfaces to applications that can be considered as ‘playful’. The interfaces to such applications should be ‘playful’ as well. The application should be fun, and interacting with such an application should, of course, be fun as well. Maybe more. Why not expect that the inte

  16. Ferroelectric Graphene-Perovskite Interfaces.

    Science.gov (United States)

    Volonakis, George; Giustino, Feliciano

    2015-07-02

    Owing to their record-breaking energy conversion efficiencies, hybrid organometallic perovskites have emerged as the most promising light absorbers and ambipolar carrier transporters for solution-processable solar cells. Simultaneously, due to its exceptional electron mobility, graphene represents a prominent candidate for replacing transparent conducting oxides. Thus, it is possible that combining these wonder materials may propel the efficiency toward the Schokley-Queisser limit. Here, using first-principles calculations on graphene-CH3NH3PbI3 interfaces, we find that graphene suppresses the octahedral tilt in the very first perovskite monolayer, leading to a nanoscale ferroelectric distortion with a permanent polarization of 3 mC/m(2). This interfacial ferroelectricity drives electron extraction from the perovskite and hinders electron-hole recombination by keeping the electrons and holes separated. The interfacial ferroelectricity identified here simply results from the interplay between graphene's planar structure and CH3NH3PbI3's octahedral connectivity; therefore, this mechanism may be effective in a much broader class of perovskites, with potential applications in photovoltaics and photocatalysis.

  17. GRAPHIC INTERFACES FOR ENGINEERING APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Ion PANA,

    2012-05-01

    Full Text Available Using effective the method of calculating Fitness for Service requires the achievement of graphical interfaces. This paper presents an example of such interfaces, made with Visual Basic program and used in the evaluation of pipelines in a research contract [4

  18. The interface at the skin

    DEFF Research Database (Denmark)

    Hansen, Lone Koefoed

    2011-01-01

    In the development of and discourses around interfaces there has always been a strong urge to bypass representation and ‘jack’ directly in to the human brain, consciousness, perceptions and feelings. In her article ”The interface at the skin” Lone Koefoed Hansen looks at how two contemporary...

  19. Playful Interfaces: Introduction and History

    NARCIS (Netherlands)

    Nijholt, Anton; Nijholt, Anton

    2014-01-01

    In this short survey we have some historical notes about human-computer interface development with an emphasis on interface technology that has allowed us to design playful interactions with applications. The applications do not necessarily have to be entertainment applications. We can have playful

  20. A species-specific activation of Toll-like receptor signaling in bovine and sheep bronchial epithelial cells triggered by Mycobacterial infections.

    Science.gov (United States)

    Ma, Yan; Han, Fei; Liang, Jinping; Yang, Jiali; Shi, Juan; Xue, Jing; Yang, Li; Li, Yong; Luo, Meihui; Wang, Yujiong; Wei, Jun; Liu, Xiaoming

    2016-03-01

    Pulmonary tuberculosis caused by a Mycobacterium infection remains a major public health problem in most part of the world, in part owing to the transmission of its pathogens between hosts including human, domestic and wild animals. To date, molecular mechanisms of the pathogenesis of TB are still incompletely understood. In addition to alveolar macrophages, airway epithelial cells have also been recently recognized as main targets for Mycobacteria infections. In an effort to understand the pathogen-host interaction between Mycobacteria and airway epithelial cells in domestic animals, in present study, we investigated the Toll-like receptor (TLR) signaling in bovine and sheep airway epithelial cells in response to an infection of Mycobacterium tuberculosis avirulent H37Ra stain or Mycobacterium bovis BCG vaccine strain, using primary air-liquid interface (ALI) bronchial epithelial culture models. Our results revealed a host and pathogen species-specific TLR-mediated recognition of pathogen-associated molecular patterns (PAMPs), induction and activation of TLR signaling pathways, and substantial induction of inflammatory response in bronchial epithelial cells in response to Mycobacteria infections between these two species. Interestingly, the activation TLR signaling in bovine bronchial epithelial cells induced by Mycobacteria infection was mainly through a myeloid differentiation factor 88 (MyD88)-independent TLR signaling pathway, while both MyD88-dependent and independent TLR signaling cascades could be induced in sheep epithelial cells. Equally noteworthy, a BCG infection was able to induce both MyD88-dependent and independent signaling in sheep and bovine airway epithelial cells, but more robust inflammatory responses were induced in sheep epithelial cells relative to the bovines; whereas an H37Ra infection displayed an ability to mainly trigger a MyD88-independent TLR signaling cascade in these two host species, and induce a more extent expression of

  1. In Situ Adsorption Studies at the Solid/Liquid Interface:Characterization of Biological Surfaces and Interfaces Using SumFrequency Generation Vibrational Spectroscopy, Atomic Force Microscopy,and Quartz Crystal Microbalance

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Diana Christine [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    Sum frequency generation (SFG) vibrational spectroscopy, atomic force microscopy (AFM), and quartz crystal microbalance (QCM) have been used to study the molecular surface structure, surface topography and mechanical properties, and quantitative adsorbed amount of biological molecules at the solid-liquid interface. The molecular-level behavior of designed peptides adsorbed on hydrophobic polystyrene and hydrophilic silica substrates has been examined as a model of protein adsorption on polymeric biomaterial surfaces. Proteins are such large and complex molecules that it is difficult to identify the features in their structure that lead to adsorption and interaction with solid surfaces. Designed peptides which possess secondary structure provide simple model systems for understanding protein adsorption. Depending on the amino acid sequence of a peptide, different secondary structures (α-helix and β-sheet) can be induced at apolar (air/liquid or air/solid) interfaces. Having a well-defined secondary structure allows experiments to be carried out under controlled conditions, where it is possible to investigate the affects of peptide amino acid sequence and chain length, concentration, buffering effects, etc. on adsorbed peptide structure. The experiments presented in this dissertation demonstrate that SFG vibrational spectroscopy can be used to directly probe the interaction of adsorbing biomolecules with a surface or interface. The use of well designed model systems aided in isolation of the SFG signal of the adsorbing species, and showed that surface functional groups of the substrate are sensitive to surface adsorbates. The complementary techniques of AFM and QCM allowed for deconvolution of the effects of surface topography and coverage from the observed SFG spectra. Initial studies of biologically relevant surfaces are also presented: SFG spectroscopy was used to study the surface composition of common soil bacteria for use in bioremediation of nuclear waste.

  2. Events at the host-microbial interface of the gastrointestinal tract III. Cell-to-cell signaling among microbial flora, host, and pathogens: there is a whole lot of talking going on.

    Science.gov (United States)

    Clarke, Marcie B; Sperandio, Vanessa

    2005-06-01

    Humans have an important association with their intestinal microbial flora. The microbial flora helps to shape the mammalian innate immune system, absorbs nutrients, and plays an intricate role on intestinal development. Microbes and mammals communicate with each other through an array of hormone and hormonelike chemical compounds. These "signals," however, are hijacked by bacterial pathogens, such as enterohemorrhagic Eschrichia coli (EHEC), to activate its virulence genes, colonize the host, and start the disease process. This review explores the cell-to-cell signaling events in the gastrointestinal tract that lead EHEC to regulate its virulence genes in a coordinate manner.

  3. Enhanced performance of CH3NH3PbI3-x Cl x perovskite solar cells by CH3NH3I modification of TiO2-perovskite layer interface.

    Science.gov (United States)

    Wang, Wen; Zhang, Zongbao; Cai, Yangyang; Chen, Jinshan; Wang, Jianming; Huang, Riyan; Lu, Xubing; Gao, Xingsen; Shui, Lingling; Wu, Sujuan; Liu, Jun-Ming

    2016-12-01

    In this work, perovskite solar cells (PSCs) with CH3NH3PbI3-x Cl x as active layer and spiro-OMeTAD as hole-transport media have been fabricated by one-step method. The methylammonium iodide (CH3NH3I) solution with different concentrations is used to modify the interface between mesoporous TiO2 (meso-TiO2) film and CH3NH3PbI3-x Cl x perovskite layer. Several techniques including X-ray diffraction, scanning electron microscopy, optical absorption, electrochemical impedance spectroscopy (EIS) and photoluminescence are used to investigate the effect of the interfacial modification. It is found that the interfacial modification by CH3NH3I enhance the crystallinity and increase the grain size of CH3NH3PbI3-x Cl x layer, and improve the surface wetting properties of perovskite precursor on meso-TiO2 film. The sunlight absorption and external quantum efficiency of PSCs in the visible region with wavelength less than 600 nm have been improved. The Nyquist plots obtained from the EIS suggest that the CH3NH3I modification can reduce the charge recombination rates. The photoluminescence measurement shows that the exciton dissociation in the modified devices is more effective than that in the control samples. The photovoltaic performance of the modified devices can be significantly improved with respect to the reference (control) devices. The CH3NH3I modified devices at the optimized concentration demonstrate the average power conversion efficiency of 12.27 % in comparison with the average efficiency of 9.68 % for the reference devices.

  4. Enhanced performance of CH3NH3PbI3- x Cl x perovskite solar cells by CH3NH3I modification of TiO2-perovskite layer interface

    Science.gov (United States)

    Wang, Wen; Zhang, Zongbao; Cai, Yangyang; Chen, Jinshan; Wang, Jianming; Huang, Riyan; Lu, Xubing; Gao, Xingsen; Shui, Lingling; Wu, Sujuan; Liu, Jun-Ming

    2016-06-01

    In this work, perovskite solar cells (PSCs) with CH3NH3PbI3- x Cl x as active layer and spiro-OMeTAD as hole-transport media have been fabricated by one-step method. The methylammonium iodide (CH3NH3I) solution with different concentrations is used to modify the interface between mesoporous TiO2 (meso-TiO2) film and CH3NH3PbI3- x Cl x perovskite layer. Several techniques including X-ray diffraction, scanning electron microscopy, optical absorption, electrochemical impedance spectroscopy (EIS) and photoluminescence are used to investigate the effect of the interfacial modification. It is found that the interfacial modification by CH3NH3I enhance the crystallinity and increase the grain size of CH3NH3PbI3- x Cl x layer, and improve the surface wetting properties of perovskite precursor on meso-TiO2 film. The sunlight absorption and external quantum efficiency of PSCs in the visible region with wavelength less than 600 nm have been improved. The Nyquist plots obtained from the EIS suggest that the CH3NH3I modification can reduce the charge recombination rates. The photoluminescence measurement shows that the exciton dissociation in the modified devices is more effective than that in the control samples. The photovoltaic performance of the modified devices can be significantly improved with respect to the reference (control) devices. The CH3NH3I modified devices at the optimized concentration demonstrate the average power conversion efficiency of 12.27 % in comparison with the average efficiency of 9.68 % for the reference devices.

  5. Power User Interface

    Science.gov (United States)

    Pfister, Robin; McMahon, Joe

    2006-01-01

    Power User Interface 5.0 (PUI) is a system of middleware, written for expert users in the Earth-science community, PUI enables expedited ordering of data granules on the basis of specific granule-identifying information that the users already know or can assemble. PUI also enables expert users to perform quick searches for orderablegranule information for use in preparing orders. PUI 5.0 is available in two versions (note: PUI 6.0 has command-line mode only): a Web-based application program and a UNIX command-line- mode client program. Both versions include modules that perform data-granule-ordering functions in conjunction with external systems. The Web-based version works with Earth Observing System Clearing House (ECHO) metadata catalog and order-entry services and with an open-source order-service broker server component, called the Mercury Shopping Cart, that is provided separately by Oak Ridge National Laboratory through the Department of Energy. The command-line version works with the ECHO metadata and order-entry process service. Both versions of PUI ultimately use ECHO to process an order to be sent to a data provider. Ordered data are provided through means outside the PUI software system.

  6. ATLAS Detector Interface Group

    CERN Multimedia

    Mapelli, L

    Originally organised as a sub-system in the DAQ/EF-1 Prototype Project, the Detector Interface Group (DIG) was an information exchange channel between the Detector systems and the Data Acquisition to provide critical detector information for prototype design and detector integration. After the reorganisation of the Trigger/DAQ Project and of Technical Coordination, the necessity to provide an adequate context for integration of detectors with the Trigger and DAQ lead to organisation of the DIG as one of the activities of Technical Coordination. Such an organisation emphasises the ATLAS wide coordination of the Trigger and DAQ exploitation aspects, which go beyond the domain of the Trigger/DAQ project itself. As part of Technical Coordination, the DIG provides the natural environment for the common work of Trigger/DAQ and detector experts. A DIG forum for a wide discussion of all the detector and Trigger/DAQ integration issues. A more restricted DIG group for the practical organisation and implementation o...

  7. Evaluation of a single cell and candidate materials with high water content hydrogen in a generic solid oxide fuel cell stack test fixture, Part II: materials and interface characterization

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Y. S.; Stevenson, Jeffry W.; Choi, Jung-Pyung

    2013-01-01

    A generic solid oxide fuel cell (SOFC) test fixture was developed to evaluate candidate materials under realistic conditions. A commerical 50 mm x 50 mm NiO-YSZ anode supported thin YSZ electrolyte cell with lanthanum strontium manganite (LSM) cathode was tested to evaluate the stability of candidate materials. The cell was tested in two stages at 800oC: stage I of low (~3% H2O) humidity and stage II of high (~30% H2O) humidity hydrogen fuel at constant voltage or constant current mode. Part I of the work was published earlier with information of the generic test fixture design, materials, cell performance, and optical post-mortem analysis. In part II, detailed microstructure and interfacial characterizations are reported regarding the SOFC candidate materials: (Mn,Co)-spinel conductive coating, alumina coating for sealing area, ferritic stainless steel interconnect, refractory sealing glass, and their interactions with each other. Overall, the (Mn,Co)-spinel coating was very effective in minimizing Cr migration. No Cr was identified in the cathode after 1720h at 800oC. Aluminization of metallic interconnect also proved to be chemically compatible with alkaline-earth silicate sealing glass. The details of interfacial reaction and microstructure development are discussed.

  8. Nanoparticle Assemblies at Fluid Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Thomas P. [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Polymer Science and Engineering

    2015-03-10

    A systematic study of the structure and dynamics of nanoparticles (NP) and NP-surfactants was performed. The ligands attached to both the NPs and NP-surfactants dictate the manner in which the nanoscopic materials assemble at fluid interfaces. Studies have shown that a single layer of the nanoscpic materials form at the interface to reduce the interactions between the two immiscible fluids. The shape of the NP is, also, important, where for spherical particles, a disordered, liquid-like monolayer forms, and, for nanorods, ordered domains at the interface is found and, if the monolayers are compressed, the orientation of the nanorods with respect to the interface can change. By associating end-functionalized polymers to the NPs assembled at the interface, NP-surfactants are formed that increase the energetic gain in segregating each NP at the interface which allows the NP-surfactants to jam at the interface when compressed. This has opened the possibility of structuring the two liquids by freezing in shape changes of the liquids.

  9. Playful user interfaces interfaces that invite social and physical interaction

    CERN Document Server

    2014-01-01

    The book is about user interfaces to applications that have been designed for social and physical interaction. The interfaces are ‘playful’, that is, users feel challenged to engage in social and physical interaction because that will be fun. The topics that will be present in this book are interactive playgrounds, urban games using mobiles, sensor-equipped environments for playing, child-computer interaction, tangible game interfaces, interactive tabletop technology and applications, full-body interaction, exertion games, persuasion, engagement, evaluation, and user experience. Readers of the book will not only get a survey of state-of-the-art research in these areas, but the chapters in this book will also provide a vision of the future where playful interfaces will be ubiquitous, that is, present and integrated in home, office, recreational, sports and urban environments, emphasizing that in the future in these environments game elements will be integrated and welcomed.

  10. Through the Interface - a human activity approach to user interfaces

    DEFF Research Database (Denmark)

    Bødker, Susanne

    In providing a theoretical framework for understanding human- computer interaction as well as design of user interfaces, this book combines elements of anthropology, psychology, cognitive science, software engineering, and computer science. The framework examines the everyday work practices...

  11. Interface gateways: defining the solutions.

    Science.gov (United States)

    Johnson, R; Zobian, M

    1994-02-01

    In summary, an interface gateway is able to quickly create and support relationships. In the healthcare environment of the 1990s, organization executives will be faced with an exponential increase in the number of provider, payor and employer alliances, affiliations and acquisitions. One of the recurring requirements in this scenario is the need to share information. Most of the data standards in existence today do not address the vast interface requirements of these organizations. However, the capabilities, flexibility and capacity of interface gateways can allow these relationships to be created and supported in a fraction of the time that conventional methods require.

  12. Practical speech user interface design

    CERN Document Server

    Lewis, James R

    2010-01-01

    Although speech is the most natural form of communication between humans, most people find using speech to communicate with machines anything but natural. Drawing from psychology, human-computer interaction, linguistics, and communication theory, Practical Speech User Interface Design provides a comprehensive yet concise survey of practical speech user interface (SUI) design. It offers practice-based and research-based guidance on how to design effective, efficient, and pleasant speech applications that people can really use. Focusing on the design of speech user interfaces for IVR application

  13. Superconducting interfaces between insulating oxides.

    Science.gov (United States)

    Reyren, N; Thiel, S; Caviglia, A D; Kourkoutis, L Fitting; Hammerl, G; Richter, C; Schneider, C W; Kopp, T; Rüetschi, A-S; Jaccard, D; Gabay, M; Muller, D A; Triscone, J-M; Mannhart, J

    2007-08-31

    At interfaces between complex oxides, electronic systems with unusual electronic properties can be generated. We report on superconductivity in the electron gas formed at the interface between two insulating dielectric perovskite oxides, LaAlO3 and SrTiO3. The behavior of the electron gas is that of a two-dimensional superconductor, confined to a thin sheet at the interface. The superconducting transition temperature of congruent with 200 millikelvin provides a strict upper limit to the thickness of the superconducting layer of congruent with 10 nanometers.

  14. The molecule-metal interface

    CERN Document Server

    Koch, Norbert; Wee, Andrew Thye Shen

    2013-01-01

    Reviewing recent progress in the fundamental understanding of the molecule-metal interface, this useful addition to the literature focuses on experimental studies and introduces the latest analytical techniques as applied to this interface.The first part covers basic theory and initial principle studies, while the second part introduces readers to photoemission, STM, and synchrotron techniques to examine the atomic structure of the interfaces. The third part presents photoelectron spectroscopy, high-resolution UV photoelectron spectroscopy and electron spin resonance to study the electroni

  15. Designing end-user interfaces

    CERN Document Server

    Heaton, N

    1988-01-01

    Designing End-User Interfaces: State of the Art Report focuses on the field of human/computer interaction (HCI) that reviews the design of end-user interfaces.This compilation is divided into two parts. Part I examines specific aspects of the problem in HCI that range from basic definitions of the problem, evaluation of how to look at the problem domain, and fundamental work aimed at introducing human factors into all aspects of the design cycle. Part II consists of six main topics-definition of the problem, psychological and social factors, principles of interface design, computer intelligenc

  16. Search-User Interface Design

    CERN Document Server

    Wilson, Max

    2011-01-01

    Search User Interfaces (SUIs) represent the gateway between people who have a task to complete, and the repositories of information and data stored around the world. Not surprisingly, therefore, there are many communities who have a vested interest in the way SUIs are designed. There are people who study how humans search for information, and people who study how humans use computers. There are people who study good user interface design, and people who design aesthetically pleasing user interfaces. There are also people who curate and manage valuable information resources, and people who desi

  17. Predicting where small molecules bind at protein-protein interfaces.

    Directory of Open Access Journals (Sweden)

    Peter Walter

    Full Text Available Small molecules that bind at protein-protein interfaces may either block or stabilize protein-protein interactions in cells. Thus, some of these binding interfaces may turn into prospective targets for drug design. Here, we collected 175 pairs of protein-protein (PP complexes and protein-ligand (PL complexes with known three-dimensional structures for which (1 one protein from the PP complex shares at least 40% sequence identity with the protein from the PL complex, and (2 the interface regions of these proteins overlap at least partially with each other. We found that those residues of the interfaces that may bind the other protein as well as the small molecule are evolutionary more conserved on average, have a higher tendency of being located in pockets and expose a smaller fraction of their surface area to the solvent than the remaining protein-protein interface region. Based on these findings we derived a statistical classifier that predicts patches at binding interfaces that have a higher tendency to bind small molecules. We applied this new prediction method to more than 10,000 interfaces from the protein data bank. For several complexes related to apoptosis the predicted binding patches were in direct contact to co-crystallized small molecules.

  18. Correlation analysis between the interface membrane and loose hip prosthesis

    Institute of Scientific and Technical Information of China (English)

    Jian-bing Ma; Yu-ming Zhang; Xiang-dong Meng; Miao Liu

    2009-01-01

    Objective To analyze the cause of prosthesis loosening by observing the interface membranes harvested during the hip restoration operation. Methods A total of 28 specimens of interface membrane around the loose prosthesis were harvested from 28 patients undergoing the restoration of total hip replacement. All the specimens underwent the observation of appearance, light microscopy and scanning electronic microscopy(SEM). Results All the gaps around the loose prosthesis were filled with interface membrane of different thickness. The color of the most interface membrane was madder red, and the other one third of membrane was black. The comparatively thicker membrane was similar to scar connective tissue while the thinner was similar to fiber membrane. A large number of wear debris, macrophages and foreign-body giant cells were found under light microscope. With SEM observation a large number of different diameter collagen fibra structures that looked like scar tissues were arranged disorderly in a great mass, foreign particles and bone debris of different size were distributed unevenly, and the fibroblast was distributed in the collagen fiber. Conclusion Wear debris is related to inflammatory cell response around the interface membrane of the loose prosthesis. The wear debris engulfed by macrophage stimulates the interface membrane to release bone resorption factors (such as TNF) which lead to osteolysis, and this is one of the most important causes of the prosthesis loosening.

  19. Accumulation of swimming bacteria near an interface

    Science.gov (United States)

    Tang, Jay; Li, Guanglai

    2012-11-01

    Microbes inhabit planet earth over billions of years and have adapted to diverse physical environment of water, soil, and particularly at or near interfaces. We focused our attention on the locomotion of Caulobacter crescentus, a singly flagellated bacterium, at the interface of water/solid or water/air. We measured the distribution of a forward swimming strain of C. crescentus near a surface using a three-dimensional tracking technique based on dark field microscopy and found that the swimming bacteria accumulate heavily within a micrometer from the surface. We attribute this accumulation to frequent collisions of the swimming cells with the surface, causing them to align parallel to the surface as they continually move forward. The extent of accumulation at the steady state is accounted for by balancing alignment caused by these collisions with rotational Brownian motion of the micrometer-sized bacteria. We performed a simulation based on this model, which reproduced the measured results. Additional simulations demonstrate the dependence of accumulation on swimming speed and cell size, showing that longer and faster cells accumulate more near a surface than shorter and slower ones do. The overarching goal of our study is to describe interfacial microbial behavior through detailed analysis of their motion. We acknowledge support by NSF PHY 1058375.

  20. Crustal fingering: solidification on a moving interface

    Science.gov (United States)

    Fu, Xiaojing; Jimenez-Martinez, Joaquin; Porter, Mark; Cueto-Felgueroso, Luis; Juanes, Ruben

    2016-11-01

    Viscous fingering-the hydrodynamic instability that takes place when a less viscous fluid displaces a more viscous fluid-is a well known phenomenon. Motivated by the formation of gas hydrates in seafloor sediments and during the ascent of gas bubbles through ocean water, here we study the interplay of immiscible viscous fingering with solidification of the evolving unstable interface. We present experimental observations of the dynamics of a bubble of Xenon in a water-filled and pressurized Hele-Shaw cell. The evolution is controlled by two processes: (1) the formation of a hydrate "crust" around the bubble, and (2) viscous fingering from bubble expansion. To reproduce the experimental observations, we propose a phase-field model that describes the nucleation and thickening of a porous solid shell on a moving gas-liquid interface. We design the free energy of the three-phase system (gas-liquid-hydrate) to rigorously account for interfacial effects, mutual solubility, and phase transformations (hydrate formation and disappearance). We introduce a pseudo-plasticity model with large variations in viscosity to describe the plate-like rheology of the hydrate shell. We present high-resolution numerical simulations of the model, which illustrate the emergence of complex "crustal fingering" patterns as a result of gas fingering dynamics modulated by hydrate growth at the interface.